Dispersionless Toda hierarchy and two-dimensional string theory

高分子化合物（High Molecular Compound）：the compound which many atom or atom group mai nly conbined by covalent bond ,relative molecular weight is above 10^4.单体（Monomer）：The raw material used to form polymer.重复单元（Repeating Unit）：The smallest basic unit which repeatedly emergence and component are the same in the lagre molecular chain of polymer .单体单元（Monomer Unit）：结构单元与原料相比，除了电子结构变化外，其原子种类和各种原子的个数完全相同，这种结构单元又称为单体单元。

结构单元（Structural Unit）：The unit monomers formed in the macromolecular chain .聚合度（DP、X n）(Degree of Polymerization) the average number of repeating unit of polymer ma cromolecular.聚合物分子量（Molecular Weight of Polymer）：The molecular weight of repeating units multiplied with the number of repeating units数均分子量(Number-average Molecular Weight)：Polymer molecules with a different numberaverag e molecular weight average molecular weight of statistics.重均分子量（Weight-average Molecular Weight）：Using different molecular weight polymermolecula r weight average molecular weight ofthe statistical average.粘均分子量（Viscosity-average Molecular Weight）：Using viscosity method to measure the molecu lar weight of polymer.分子量分布（Molecular Weight Distribution, MWD ）：Because different molecular weight polymersa re generally composed of a mixture ofhomologues, it has a certain molecular weightdistribution,多分散性（Polydispersity）：Used to express the size of the polymermolecular weight does not equ al more technical terms is called dispersion.分布指数(Distribution Index) ：The ratio of Molecular Weight and Number-average Molecular Weigh t。

Atomic Absorption AAnalyst 400 AASpectrometerControl and Data SystemUser Interface Complete PC control of all functions of the AAnalyst™ 400 using WinLab32™ for AA software. WinLab32 for AA includes an innovative user interface that makes the software easy to learn and use, including a clear graphical design, task-oriented organization of the windows, an understandablevocabulary, extensive tool tips in multiple languages, simple data displays and Wizards for the simplification of many tasks.WinLab32 is fully multitasking, allowing the analyst to report analytical results, view data or add priority samples without interrupting the analysis in progress.Using WinLab32 software, setup is flexible and easy. Standard operating conditions for flame, graphite furnace and FIAS techniques are included.Auto Analysis Control links methods for each technique with a sample-information file. The sample list can be created by third-party software orLIMS and downloaded to the system.WinLab32 software provides many tools to increase lab productivity. With WinLab32 Offline, method and sample-information files can be createdand data reviewed or reprocessed without interrupting the current analysis.WinLab32 software provides extensive QC protocols to meet internal and regulatory requirements. Data Reprocessing allows changes to manymethod and sample-information parameters after data collection and the recalculation of the results using the new parameters. With DataReprocessing, the raw data are never altered, thereby ensuring data integrity is maintained.WinLab32 Reporter provides the ability to generate post-run reports in a variety of formats. The Export feature of Data Manager can be used toexport results as comma-delimited ASCII files for compatibility with commercial third-party programs such as Microsoft® Excel®, Access® and Word.21 CFR Part 11 An optional WinLab32 Enhanced Security™ package is available for labs needing to be compliant with 21 CFR Part 11 regulations.HardwareSystem True double-beam echelle optical system. Front surfaced, reflecting optics with protective coating. Deuterium background corrector and two built-in EDL power supplies.Optical System Echelle monochromator. Focal length: 300 mm. Grating: 36 x 185 mm area, 79 lines/mm, blaze angle 76˚. Fused-quartz prism: 95 x 40 mm, 60°.Wavelength: 189-900 nm. Spectral bandpass: 0.15 nm at 200 nm. Reciprocal linear dispersion: 2.4 nm/mm. The photometer optics are covered toprotect against dust and corrosive vapors. For maximum protection, the optical system can be purged with an inert gas.Detector High-efficiency, segmented solid-state detector.Light Sources Hollow cathode or electrodeless discharge lamps (EDLs). EDLs provide much higher light output and longer lifetime when compared to conventional hollow cathode lamps. Lamp elements, recommended operating currents and slit selection are automatically recognized and set when usingPerkinElmer® Lumina™ series AA lamps. Lamp alignment is completely automatic with the four-lamp turret.E-box All electronics are located in a single user-replaceable module that the operator can easily replace without requiring a service visit.For a complete listing of our global offices, visit /ContactUsCopyright ©2004-2010, PerkinElmer, Inc. All rights reserved. PerkinElmer ® is a registered trademark of PerkinElmer, Inc. All other trademarks are the property of their respective owners. PerkinElmer reserves the right to change this document at any time without notice and disclaims liability for editorial, pictorial or typographical errors. 006675E_01PerkinElmer, Inc. 940 Winter Street Waltham, MA 02451 USA P: (800) 762-4000 or (+1) Gas Controls and Burner SystemFlame GasFully automated gas box with computer-controlled oxidant selection, automatic gas sequencing, oxidant and fuel monitoring and control.ControlSoftware-actuated ignition with air/acetylene. Acetylene flow is automatically adjusted when switching to or from nitrous-oxide/acetylene operation.Flame SafetyFully interlocked operation prevents ignition if the proper burner head, the nebulizer, end cap or burner drain system are not correctly Featuresinstalled, the level of the liquid in the drain vessel is incorrect, or gas pressures are too low. Interlocks will automatically shut d own thegases if a flame is not detected. The flame is automatically and safely extinguished in the event of a power failure or when theemergency flame-off button is used.Burner SystemAn inert-polymer mixing chamber provides superior analysis of corrosive and high-solid matrices. The spray chamber is manufactured froma high-strength composite, eliminating the need for pressure-relief devices. The high-precision inert nebulizer maximizes stability andsensitivity. A 10-cm single-slot solid titanium burner head for air/acetylene operation is included. Optional burner heads include: 5-cmnitrous-oxide/acetylene, 10-cm three-slot air/acetylene and 5-cm single-slot air/acetylene.Sample Area 25 cm wide x 25 cm deep sample compartment for easy access to burner components.Accessories for the AAnalyst 400AutosamplersFlame autosamplers automate standard and sample introductions for instrument calibration and sample analysis, extending thespectrometer’s capabilities to those of a fully automated analytical workstation. Sample Dilution The AutoPrep 50 sample-dilution system provides an optimized tool for truly automated flame AA. With automatic, intelligent on-line dilution capabilities, the AutoPrep 50 eliminates the time-consuming, manual, error-prone portion of your flame AA analyses.Mercury/Hydride For the analysis of mercury or hydride-forming elements, an optional automated flow injection system or a manual mercury/hydride System system can be added. Flow Injection Atomic Spectroscopy (FIAS) combines the advantages of mercury/hydride AA with those of the flow injection, enabling mercury/hydride AA procedures to be truly automated.System SpecificationsDimensions70 x 65 (0.46 m 2) x 65 cm (W x D x H)Weight49 kg Power100-230 V (±10%), 50/60 Hz (±1%), 300 VA (maximum)TechnicalClassified as a laboratory instrument. Complies with the applicable European Union directives and standards for safety and electro-magnetic compatibility for CE Marking, the safety requirements for Canada and the United States for CSA/NRTL certification and the FCC requirements for radio-frequency emissions. The instrument was developed and produced in compliance with ISO 9001.Environmental Dust-free, free of vibrations, ambient temperatures: +15 ˚C to +35 ˚C with a change rate of a maximum 3 ˚C per hour. Relative humidity: 20% to 80% non-condensing.。

Literary history as a challenge to literary theoryHans Robert JaussIn our time literary history has increasingly fallen into disrepute,and not at all without reason.The history of this worthy discipline in the last one hundred and fty years unmistakably describes the path of a steady decline.Its greatest achievements all belong to the nineteenth century.To write the history of a national literature counted,in the times of Gervinus and Scherer,De Sanctis and Lanson,as the crowning life’s work of the philologist.The patriarchs of the discipline saw their highest goal therein,to represent in the history of literary works[Dichtwerke] the idea of national individuality on its way to itself.This high point is already a distant memory.The received form of literary history scarcely scratches out a living for itself in the intellectual life of our time.It has maintained itself in requirements for examinations by the state system of examinations that are themselves ready for dismantling.As a compulsory subject in the high school curriculum,it has almost disappeared in Germany.Beyond that,literary histories are still to be found only, if at all,on the bookshelves of the educated bourgeoisie who for the most part opens them,lacking a more appropriate literary dictionary,to answer literary quiz questions.In university course catalogs literary history is clearly disappearing.It has long been no secret that the philologists of my generation even rather pride themselves in having replaced the traditional presentation of their national literature by periods and as a whole with lectures on the history of a problem or with other systematic approaches.Scholarly production o ers a corresponding picture:collective projects in the form of handbooks,encyclopedias,and(as the latest o shoot of the so-called “publisher’s synthesis”)series of collected interpretations have driven out literary histories as unserious and presumptuous.Signi cantly,such pseudohistorical col-lections seldom derive from the initiative of scholars,rather most often from the whim of some restless publisher.Serious scholarship on the other hand precipitates into monographs in scholarly journals and presupposes the stricter standard of the literary critical methods of stylistics,rhetoric,textual philology,semantics,poetics, morphology,historical philology,and the history of motifs and genres.Philolog-ical scholarly journals today are admittedly in good part still lled with articles that content themselves with a literary historical approach.But their authors nd themselves facing a twofold critique.Their formulations of the question are,from the perspective of neighboring disciplines,quali ed publicly or privately as pseudo-problems,and their results put aside as mere antiquarian knowledge.The critique of literary theory scarcely sees the problem any more clearly.It nds fault with classical literary history in that the latter pretends to be only one form of history writing,but in truth operates outside the historical dimension and thereby lacks the foundation of aesthetic judgment demanded by its object—literature as one of the arts.This critique should rst be made clear.Literary history of the most convenient forms tries to escape from the dilemma of a mere annal-like lining-up of the facts by arranging its material according to general tendencies,genres,and what-have-you, in order then to treat within these rubrics the individual works in chronological series.In the form of an excursis,the author’s biography and the evaluation of their oeuvre pop up in some accidental spot here,in the manner of an occasional aside.Or this literary history arranges its material unilinearly,according to the chronology of great authors,and evaluates them in accordance with the schema of“life and works;”the lesser authors are here overlooked(they are settled in the interstices), and the development of genres must thereby also unavoidably be dismembered. The second form is more appropriate to the canon of authors of the classics;the rst is found more often in the modern literatures that have to struggle with the di culty—growing up to and in the present—of making a selection from a scarcely surveyable list of authors and works.But a description of literature that follows an already sanctioned canon and simply sets the life and work of the writers one after another in a chronological series is,as Gervinus already remarked,“no history;it is scarcely the skeleton of a history.”By the same token,no historian would consider historical a presentation of literature by genres that,registering changes from work to work,followed the unique laws of the forms of development of the lyric,drama,and novel and merely framed the unclari ed character of the literary development with a general obser-vation(for the most part borrowed from historical studies)concerning the Zeitgeist and the political tendencies of the age.On the other hand it is not only rare but al-most forbidden that a literary historian should hold judgments of quality concern-ing the works of past ages.Rather,he prefers to appeal to the ideal of objectivity of historiography,which only has to describe“how it really was.”His aesthetic absti-nence has good grounds.For the quality and rank of a literary work result neither from the biographical or historical conditions of its origin[Entstehung],nor from its place in the sequence of the development of a genre alone,but rather from the criteria of in uence,reception,and posthumous fame,criteria that are more di -cult to grasp.And if a literary historian,bound by the ideal of objectivity,limits himself to the presentation of a closed past,leaving the judgment of the literature of his own,still-un nished age to the responsible critics and limiting himself to the secure canon of“masterpieces,”he remains in his historical distance most often one to two generations behind the latest development in literature.At best he partakes of the contemporary engagement with literary phenomena of the present as a pas-sive reader,and thereby becomes in the formation of his judgment a parasite of acriticism that he silently despises as“unscholarly.”What then should a historical study of literature still be today,a study that—taking up a classical de nition of the interest in history,that of Friedrich Schiller—can promise so little instruction to the “thoughtful observer,”no imitative model at all to the“active man of the world,”no important information to the“philosopher,”and everything else but a“source of the noblest pleasure”to the reader?Thesis .A renewal of literary history demands the removal of the prejudices of historical objectivism and the grounding of the traditional aesthetics of production and representation in an aesthetics of reception and in uence.The historicity of literature rests not on an organization of“literary facts”that is established post festum,but rather on the preceding experience of the literary work by its readers.R.G.Collingwood’s postulate,posed in his critique of the prevailing ideology of objectivity in history—“History is nothing but the re-enactment of past thought in the historian’s mind”—is even more valid for literary history.For the positivistic view of history as the“objective”description of a series of events in an isolated past neglects the artistic character as well as the speci c historicity of literature.A literary work is not an object that stands by itself and that o ers the same view to each reader in each period.It is not a monument that monologically reveals its timeless essence.It is much more like an orchestration that strikes ever new reso-nances among its readers and that frees the text from the material of the words and brings it to a contemporary existence:“words that must,at the same time that they speak to him,create an interlocutor capable of understanding them.”This dialogical character of the literary work also establishes why philological understanding can exist only in a perpetual confrontation with the text,and cannot be allowed to be reduced to a knowledge of facts.Philological understanding always remains related to interpretation that must set as its goal,along with learning about the object,the re ection on and description of the completion of this knowledge as a moment of new understanding.History of literature is a process of aesthetic reception and production that takes place in the realization of literary texts on the part of the receptive reader,the re- ective critic,and the author in his continuing productivity.The endlessly growing sum of literary“facts”that winds up in the conventional literary histories is merely left over from this process;it is only the collected and classi ed past and therefore not history at all,but pseudo-history.Anyone who considers a series of such liter-ary facts as a piece of the history of literature confuses the eventful character of a work of art with that of historical matter-of-factness.The Perceval of Chrétien de Troyes,as a literary event,is not“historical”in the same sense as,for example,the Third Crusade,which was occurring at about the same time.It is not a“fact”that could be explained as caused by a series of situational preconditions and motives, by the intent of a historical action as it can be reconstructed,and by the necessary and secondary consequences of this deed.The historical context in which a literary work appears is not a factical,independent series of events that exists apart from an observer.Perceval becomes a literary event only for its reader,who reads thislast work of Chrétien with a memory of his earlier works and who recognizes its individuality in comparison with these and other works that he already knows,so that he gains a new criterion for evaluating future works.In contrast to a politi-cal event,a literary event has no unavoidable consequences subsisting on their own that no succeeding generation can ever escape.A literary event can continue to have an e ect only if those who come after it still or once again respond to it—if there are readers who again appropriate the past work or authors who want to imitate, outdo,or refute it.The coherence of literature as an event is primarily mediated in the horizon of expectations of the literary experience of contemporary and later readers,critics,and authors.Whether it is possible to comprehend and represent the history of literature in its unique historicity depends on whether this horizon of expectations can be objecti ed.。

沉淀法的英语The Precipitation Method。

The precipitation method is a widely used technique in various scientific fields, including chemistry, material science, and environmental science. It involves the formation of a solid precipitate from a solution by adding a precipitating agent. This method is valuable for the synthesis of new materials, the purification of substances, and the removal of pollutants from wastewater. In this article, we will explore the principles, applications, and advantages of the precipitation method.The principle behind the precipitation method lies in the solubility of different compounds in a solvent. When two solutions containing ions that can react with each other are mixed, the solubility product is exceeded, resulting in the formation of an insoluble compound or precipitate. The precipitate can then be separated from the solution through filtration or centrifugation.One of the key applications of the precipitation method is in the synthesis of new materials. By carefully controlling the reaction conditions, researchers can produce nanoparticles, nanowires, and other nanostructures with specific properties. For example, by varying the concentration and pH of the solutions, the size and morphology of the precipitate can be controlled, leading to materials with different optical, electrical, or catalytic properties.Another important application of the precipitation method is in the purification of substances. Impurities can be selectively removed by precipitating them out of the solution. This is particularly useful in the pharmaceutical industry, where the purity of drugs is of utmost importance. By adding a suitable precipitating agent, impurities can be removed, resulting in a higher purity product.The precipitation method also finds application in environmental science, particularly in the treatment of wastewater. Many pollutants, such as heavy metals and organic compounds, can be removed from wastewater by precipitating them as insolublecompounds. This is an effective and economical method for the removal of pollutants before the treated water is discharged into the environment.One of the advantages of the precipitation method is its simplicity and cost-effectiveness. The equipment required for the process is relatively simple and inexpensive, making it accessible to researchers and industries with limited resources. Additionally, the precipitation method can be easily scaled up for large-scale production, making it suitable for industrial applications.However, the precipitation method also has its limitations. One challenge is the control of the size and morphology of the precipitate. The formation of unwanted by-products or the aggregation of particles can occur, affecting the desired properties of the final product. Therefore, careful optimization of the reaction conditions is necessary to achieve the desired results.In conclusion, the precipitation method is a valuable technique in various scientific fields. It allows for the synthesis of new materials, the purification of substances, and the removal of pollutants from wastewater. With its simplicity and cost-effectiveness, it is widely used in research and industrial applications. However, careful control of the reaction conditions is crucial to obtain the desired properties of the precipitate. Further research and development in this area will continue to enhance the effectiveness and efficiency of the precipitation method.。

1087 APPARENT INTRINSIC DISSOLUTION—DISSOLUTION TESTING PROCEDURES FOR ROTATING DISK ANDSTATIONARY DISKThis general information chapter Apparent Intrinsic Dissolution—Dissolution Testing Procedures for Rotating Disk and Stationary Disk 1087 discusses the determination of dissolution rates from nondisintegrating compacts exposing a fixed surface area to a given solvent medium. Compact, as used here, is a nondisintegrating mass resulting from compression of the material under test using appropriate pressure conditions. A single surface having specified physical dimensions is presented for dissolution. Determination of the rate of dissolution can be important during the course of the development of new chemical entities because it sometimes permits prediction of potential bioavailability problems and may also be useful to characterize compendial articles such as excipients or drug substances. Intrinsic dissolution studies are characterization studies and are not referenced in individual monographs. Information provided in this general information chapter is intended to be adapted via a specific protocol appropriate to a specified material.Dissolution rate generally is expressed as the mass of solute appearing in the dissolution medium per unit time (e.g., mass sec–1), but dissolution flux is expressed as the rate per unit area (e.g., mass cm–2 sec–1). Reporting dissolution flux is preferred because it is normalized for surface area, and for a pure drug substance is commonly called intrinsic dissolution rate. Dissolution rate is influenced by intrinsic solid-state properties such as crystalline state, including polymorphs and solvates, as well as degree of noncrystallinity. Numerous procedures are available for modifying the physicochemical properties of chemical entities so that their solubility and dissolution properties are enhanced. Among these are coprecipitates and the use of racemates and enantiomeric mixtures. The effect of impurities associated with a material can also significantly alter its dissolution properties. Dissolution properties are also influenced by extrinsic factors such as surface area, hydrodynamics, and dissolution medium properties, including solvent (typically water), presence of surfactants, temperature, fluid viscosity, pH, buffer type, and buffer strength.Rotating disk and stationary disk dissolution procedures are sufficiently versatile to allow the study of characteristics of compounds of pharmaceutical interest under a variety of test conditions. Characteristics common to both apparatuses include the following:1.They are adaptable to use with standard dissolution testing stations, and both use a tablet die to hold the nondisintegratingcompact during the dissolution test.2.They rely on compression of the test compound into a compact that does not flake or fall free during the dissolution test.3. A single surface of known geometry and physical dimension is presented for dissolution.4.The die is located at a fixed position in the vessel, which decreases the variation of hydrodynamic conditions.A difference between the two procedures is the source of fluid flow over the dissolving surface. In the case of the rotating disk procedure, fluid flow is generated by the rotation of the die in a quiescent fluid, but fluid flow is generated by a paddle or other stirring device for the stationary disk procedure.EXPERIMENTAL PROCEDUREThe procedure for carrying out dissolution studies with the two types of apparatus consists of preparing a nondisintegrating compact of material using a suitable compaction device, placing the compact and surrounding die assembly in a suitable dissolution medium, subjecting the compact to the desired hydrodynamics near the compact surface, and measuring the amount of dissolved solute as a function of time.Compacts are typically prepared using an apparatus that consists of a die, an upper punch, and a lower surface plate fabricated out of hardened steel or other material that allows the compression of material into a nondisintegrating compact. An alternative compaction apparatus consists of a die and two punches. Other configurations that achieve a nondisintegrating compact of constant surface area also may be used. The nondisintegrating compact typically has a diameter of 0.2 cm to 1.5 cm.Compact PreparationAttach the smooth lower surface plate to the underside of the die, or alternatively, insert the lower punch using an appropriate clamping system. Accurately weigh a quantity of material necessary to achieve an acceptable compact and transfer to the die cavity. Place the upper punch into the die cavity, and compress the powder on a hydraulic press at a compression pressure required to form a nondisintegrating compact that will remain in the die assembly for the length of the test. Compression for 1 minute at 15 MPa usually is sufficient for many organic crystalline compounds, but alternative compression conditions that avoid the formation of capillaries should be evaluated. For a given substance, the compact preparation, once optimized is standardized to facilitate comparison of different samples of the substance.Changes in crystalline form may occur during compression; therefore, confirmation of solid state form should be performed by powder X-ray diffraction or other similar technique. Remove the surface plate or lower punch. Remove loose powder from the surface of the compact and die by blowing compressed air or nitrogen over the surface.Dissolution MediumThe choice of dissolution medium is an important consideration. Whenever possible, testing should be performed under sink conditions to avoid artificially retarding the dissolution rate due to approach of solute saturation of the medium. Dissolutionmeasurements are typically made in aqueous media. To approximate in vivo conditions, measurements may be run in the physiological pH range at 37. The procedure when possible is carried out under the same conditions that are used to determine the intrinsic solubility of the solid state form being tested. Dissolution media should be deaerated immediately prior to use to avoid air bubbles forming on the compact or die surface.1The medium temperature and pH must be controlled, especially when dealing with ionizable compounds and salts. In the latter cases, the dissolution rate may depend strongly on the pH, buffer species, and buffer concentration. A simplifying assumption in constant surface area dissolution testing is that the pH at the surface of the dissolving compact is the same as the pH of the bulk dissolution medium. For nonionizable compounds, this is relatively simple because no significant pH dependence on dissolution rate is expected. For acids and bases, the solute can alter the pH at and near the surface of the compact as it dissolves. Under these conditions, the pH at the surface of the compact may be quite different from the bulk pH due to the self-buffering capacity of the solute. To assess intrinsic solubility, experimental conditions should be chosen to eliminate the effect of solute buffering, alteration of solution pH, and precipitation of other solid state forms at the surface of the compact. For weak acids, the pH of the dissolution medium should be one to two pH units below the pKa of the dissolving species. For weak bases, the pH of the dissolution medium should be one to two pH units above the pKa of the dissolving species.ApparatusRotating Disk— A typical apparatus (Figure 1) consists of a punch and die fabricated out of hardened steel. The base of the die has three threaded holes for the attachment of a surface plate made of polished steel, providing a mirror-smooth base for the compacted pellet. The die has a cavity into which is placed a measured amount of the material whose intrinsic dissolution rate is to be determined. The punch is then inserted in the die cavity and the test material is compressed with a hydraulic press. [NOTE—A hole through the head of the punch allows insertion of a metal rod to facilitate removal from the die after the test.] A compacted pellet of the material is formed in the cavity with a single face of defined area exposed on the bottom of the die.Figure 1The die assembly is then attached to a shaft constructed of an appropriate material (typically steel). The shaft holding the die assembly is positioned so that when the die assembly is lowered into the dissolution medium (Figure 2) the exposed surface of the compact will be not less than 1.0 cm from the bottom of the vessel and nominally in a horizontal position. The die assembly should be aligned to minimize wobble, and air bubbles should not be allowed to form on the compact or die surface.Figure 2A rotating disk speed of 300 rpm is recommended. Typical rotation speeds may range from 60 rpm to 500 rpm. The dissolution rate depends on the rotation speed used. This parameter should be selected in order to admit at least five sample points during the test, but excessive stirring speeds may create shear patterns on the surface of the dissolving material that could cause aberrant results (i.e., nonlinearity). Typically, the concentration of the test specimen is measured as a function of time, and the amount dissolved is then calculated. The sampling interval will be determined by the speed of the dissolution process. If samples are removed from the dissolution medium, the cumulative amount dissolved at each time point should be corrected for losses due to sampling.Stationary Disk— The apparatus (Figure 3) consists of a steel punch, die, and a base plate. The die base has three holes for the attachment of the base plate. The three fixed screws on the base plate are inserted through the three holes on the die and then fastened with three washers and nuts. The test material is placed into the die cavity. The punch is then inserted into the cavity and compressed, with the aid of a bench top press. The base plate is then disconnected from the die to expose a smooth compact pellet surface. A gasket is placed around the threaded shoulder of the die and a polypropylene cap is then screwed onto the threaded shoulder of the die.The die assembly is then positioned at the bottom of a specially designed dissolution vessel with a flat bottom (Figure 4). The stirring unit (e.g., paddle) is positioned at an appropriate distance (typically 2.54 cm) from the compact surface. The die assembly and stirring unit should be aligned to ensure consistent hydrodynamics, and air bubbles should not be present on the compact surface during testing. Alternative configurations may be utilized if adequate characterization and control of the hydrodynamics can be established.Figure 3Figure 4The dissolution rate depends on the rotation speed and precise hydrodynamics that exist. Typically, the concentration of the test specimen is measured as a function of time, and the amount dissolved is then calculated. The sampling interval will be determined by the speed of the dissolution process (see Rotating Disk). If samples are removed from the dissolution medium, the cumulative amount dissolved at each time point should be corrected for losses due to sampling.DATA ANALYSIS AND INTERPRETATIONThe dissolution rate is determined by plotting the cumulative amount of solute dissolved against time. Linear regression analysis is performed on data points in the initial linear region of the dissolution curve. The slope corresponds to the dissolution rate (mass sec–1). (More precise estimates of slope can be obtained using a generalized linear model that takes into account correlations among the measurements of the cumulative amounts dissolved at the various sampling times.)The amount versus time profiles may show curvature. When this occurs, only the initial linear portion of the profile is used todetermine the dissolution rate. Upward curvature (positive second derivative) of the concentration versus time data is typicallyindicative of a systematic experimental problem. Possible problems include physical degradation of the compact by cracking, delaminating, or disintegration. Downward (negative second derivative) curvature of the dissolution profile is often indicative of a transformation of the solid form of the compact at the surface or when saturation of the dissolution medium is inadvertently being approached. This often occurs when a less thermodynamically stable crystalline form converts to a more stable form. Examples include conversion from an amorphous form to a crystalline form or from an anhydrous form to a hydrate form, or the formation of a salt or a salt converting to the corresponding free acid or free base. If such curvature is observed, the crystalline form of the compact may be assessed by removing it from the medium and examining it by powder X-ray diffraction or another similar technique to determine if the exposed surface area is changing.The constant surface area dissolution rate is reported in units of mass sec –1, and the dissolution flux is reported in units of mass cm –2 sec –1. The dissolution flux is calculated by dividing the dissolution rate by the surface area of the compact. Test conditions, typically a description of the apparatus, rotation speed, temperature, buffer species and strength, pH, and ionic strength should also be reported with the analyses.1 One method of deaeration is as follows: Heat the medium, while stirring gently, to about 41, immediately filter under vacuum using a filter having a porosity of 0.45 µm or less, with vigorous stirring, and continue stirring under vacuum for about 5 minutes. Other deaeration techniques for removal of dissolved gases may be used.Auxiliary Information— Please check for your question in the FAQs before contacting USP.USP32–NF27 Page 549Pharmacopeial Forum : Volume No. 33(2) Page 269 Topic/QuestionContact Expert Committee General Chapter William E. BrownSenior Scientist1-301-816-8380(BPC05) Biopharmaceutics05。

抑制锂枝晶的有效途径——高浓度LiFSI电解液随着科技发展，人类对能源的需求与日俱增，而目前商业化的锂离子电池（理论容量372mAh/g）已不能满足该需求，高容量密度电池的开发已成为研究热点。

锂金属具有高理论比容量（3860mAh/g），在储能领域有很大应用潜力。

然而锂枝晶的生长，不仅降低了电池性能，而且容易发生短路，造成安全隐患。

这些问题严重阻碍了锂金属电池的发展和实际应用。

为解决上述问题，科学家们提出了各种方案，如制备三维嵌锂基体、锂金属表面包覆、隔膜改性等。

但这些方式增加了电池整体重量，且制备过程繁琐，不利于商业化生产。

最近，Qian等通过对比不同电解液环境对锂枝晶生长的影响，提出高浓度LiFSI醚类电解液环境下，即使没有嵌锂基体，仍可有效抑制锂枝晶在铜集流体上的生长，同时，电池库伦效率也有显著提高。

Figure 1. Schematicillustrations of battery configurations. a) State-of-the-art Li-ion battery,i.e., Cu|C6||LiFePO4|Al. b) Anode-free battery,i.e.,Cu||LiFePO4|Al. 实验以Cu-LiFePO4电池为研究体系，分别选用1 MLiPF6-EC/DMC(1/2 v/v)酯类电解液和4 MLiFSI-DME醚类电解液进行对比。

实验结果表明随着循环次数增加，酯类电解液环境下电池电阻增加明显，而4 MLiFSI-DME醚类电解液环境下，电阻增幅较小。

而且在4 MLiFSI-DME环境下，多次循环后平均库伦效率大于99%。

即使在2 mA cm-2电流密度下，库伦效率仍接近100%。

另外，该研究发现通过调节测试条件，也可提高库伦效率。

当锂以0.2 mA cm-2沉积，2mA cm-2脱出时，平均库伦效率可达99.6%，高于一直以0.2 mA cm-2/2mAcm-2进行循环的库伦效率。

OIKOS 90:7–19.Copenhagen 2000Minireviews provides an opportunity to summarize existing knowledge of selected ecological areas,with special emphasis on current topics where rapid and significant advances are occurring.Reviews should be concise and not too wide-ranging.All key references should be cited.A summary is required.MINI-REVIEWOn the usage and measurement of landscape connectivityLutz Tischendorf and Lenore FahrigTischendorf,L.and Fahrig,L.2000.On the usage and measurement of landscape connectivity.–Oikos 90:7–19.This paper examines the usage and measurement of ‘‘landscape connectivity’’in 33recent studies.Connectivity is defined as the degree to which a landscape facilitates or impedes movement of organisms among resource patches.However,connectivity is actually used in a variety of ways in the literature.This has led to confusion and lack of clarity related to (1)function vs structure,(2)patch isolation vs landscape connectivity and,(3)corridors vs connectivity.We suggest the term connectivity should be reserved for its original purpose.We highlight nine studies;these include modeling studies that actually measured connectivity in accordance with the defini-tion,and empirical studies that measured key components of connectivity.We found that measurements of connectivity provide results that can be interpreted as recom-mending habitat fragmentation to enhance landscape connectivity.We discuss rea-sons for this misleading conclusion,and suggest a new way of quantifying connectivity,which avoids this problem.We also recommend a method for reducing sampling intensity in landscape-scale empirical studies of connectivity.L .Tischendorf and L .Fahrig ,Ottawa -Carleton Inst .of Biology ,Carleton Uni 6.,Ottawa ,ON ,Canada K 1S 5B 6(present address of LT :Busestrasse 76,D -28213Bremen ,Germany [tischendorf@cla 6is -bremen .de ]).What is landscape connectivity?The effects of spatial structure (patchiness)on popu-lation dynamics were first examined in patch-based population models beginning in the early 1970s (e.g.,Levins 1969,Reddingius and den Boer 1970,Levin 1974,1976,Roff 1974).Further modeling studies showed that assumptions about movement among habitat patches greatly influence the predictions of such models (e.g.,Lefkovitch and Fahrig 1985,Fahrig 1988,1990,Fahrig and Paloheimo 1988,Henein and Merriam 1990,Adler and Nuernberger 1994,Lindenmayer and Lacy 1995,Lindenmayer and Possingham 1996,Frank and Wissel 1998,Henein et al.1998).Movement among habitat patches is,how-ever,not simply a function of an organism itself,but also depends on the landscape through which it must move.To emphasize the interaction between species’attributes and landscape structure in determining movement of organisms among habitat patches,Mer-riam (1984)introduced the concept of ‘‘landscape connectivity’’.OIKOS 90:1(2000)7Accepted 31January 2000Copyright ©OIKOS 2000ISSN 0030-1299Printed in Ireland –all rights reservedTaylor et al.(1993)defined landscape connectivity as ‘‘the degree to which the landscape facilitates or im-pedes movement among resource patches’’.Similarly, With et al.(1997)defined landscape connectivity as ‘‘the functional relationship among habitat patches, owing to the spatial contagion of habitat and the movement responses of organisms to landscape struc-ture’’.These definitions accentuate the dependence of movement on landscape structure,which suggests that connectivity is species-and landscape-specific.One must therefore describe landscape structure from a species’point of view(Wiens and Milne1989).This starts with defining the species’habitat.The next step is to determine the scale at which the species responds to landscape structure,through itsfine-scale(grain)and large-scale(extent)movement(Wiens1997).This deter-mines the scale of habitat pattern as perceived by the organism.Finally,one must determine how the species responds to the different elements of a landscape.This comprises the species movement pattern and mortality risk on landscape elements(patches)as well as reactions at boundaries.Note that all of these behavioral facets contribute toward facilitating or impeding movement among resource patches.In summary,landscape connectivity encapsulates the combined effects of(1)landscape structure and(2)the species’use,ability to move and risk of mortality in the various landscape elements,on the movement rate among habitat patches in the landscape. Objective and approachWe reviewed the literature covered by the Agriculture, Biology&Environmental Sciences Edition of the Cur-rent Contents database(CC1998),from May1993to November1998.We searched article titles and key words for the term connecti6ity in combination with landscape or patch or habitat.The search resulted in49 papers.However,17of these papers did not use con-nectivity at all.We omitted these from the review,and included one other paper(Doak et al.1992)leaving33 papers,which are assembled in descending chronologi-cal and alphabetical order in Table1,and classified in Fig.1.Our objective was to examine the current usage and measurement of landscape connectivity.We start with a critical discussion of the diverse usage of connectivity, followed by a description of modeling and empirical studies that actually attempted to quantify connectivity or key components of it.We then discuss crucial model-ing assumptions and reveal the deceptive paradox of patch-based connectivity measurements,and its poten-tial for misleading conclusions.We end by suggesting ways to streamline and focus research on landscape connectivity.Current usage of connectivityStructure or function?The literature review revealed that the term connectiv-ity is sometimes used as a functional concept and other times in a structural way.Structural connectivity is equated with habitat contiguity and is measured by analyzing landscape structure,independent of any at-tributes of the organism(s)of interest(Collinge and Forman1998).The functional concept of connectivity explicitly con-siders the behavioral responses of an organism to the various landscape elements(patches and boundaries). Consequently,functional connectivity covers situations where organisms venture into non-habitat(matrix), where they may(1)face higher mortality risks(e.g., Lidicker1975,Gaines and McGlenaghan1980,Krohne and Burgin1987,Henein and Merriam1990,Schippers et al.1996,Charrier et al.1997,Poole1997,Sakai and Noon1997),(2)express different movement patterns (e.g.,Baars1979,Rijnsdorp1980,Wallin and Ekbom 1988,Wegner and Merriam1990,Hansson1991,John-son et al.1992a,Andreassen et al.1996b,Matter1996, Charrier et al.1997,Collins and Barrett1997),and(3) cross boundaries(e.g.,Mader1984,Wiens et al.1985, Bakowski and Kozakiewicz1988,Merriam et al.1989, Duelli et al.1990,Mader et al.1990,Frampton et al. 1995,Mauremooto et al.1995,Charrier et al.1997, Sakai and Noon1997).Depending on the movement attributes of the organ-ism,structural and functional connectivity can be syn-onymous.This occurs when the organism’s movement is confined to its preferred habitat,i.e.,individuals do not cross the habitat/matrix boundary,and the organ-ism moves freely within the preferred habitat(e.g., Bascompte and Sole´1996).This is the assumption behind most percolation-based connectivity measures (Gardner et al.1987,Gardner and O’Neill1991,Green 1994).The fact that structural connectivity is relatively easy to measure could lead to the conclusion that connectiv-ity is a generalized feature of a landscape.This would be erroneous.In fact,the same landscape will have different connectivities for different organisms.Struc-turally connected habitat patches still may not be func-tionally connected and even non-contiguous habitat patches may be functionally connected,depending on the species(With1997).For example,if the only two habitat patches in a landscape are structurally con-nected by an inappropriate corridor for the species in question(too narrow or too long),structural connectiv-ity would exist without successful movement(functional response)from one patch to the other.Likewise,non-contiguous habitat patches may functionally be con-nected if the species can cross the non-habitat area (matrix)successfully and move between habitat8OIKOS90:1(2000)OIKOS 90:1(2000)9T a b l e 1.C h r o n o l o g i c a l a n d a l p h a b e t i c a l a s s e m b l a g e o f t h e 33r e v i e w e d c o n n e c t i v i t y s t u d i e s .S t u d y t y p e a n d d u r a t i o nS t u d yN o .M e a s u r e m e n t /u s a g e o f c o n n e c t i v i t yC o m m e n t s /s t u d y t a r g e t S p a t i a l s c a l e A n d r e a s s e n e t l a n d s c a p e e f f e c t s o n m o v e m e n t f r e q u e n c i e s e x p e r i m e n t ,r a d i o -t r a c k i n g ,13w k ,3p r e s e n c e /a b s e n c e o f c o r r i d o r s1g e n e r a t i o n s a l .1998e f f e c t o f s t r u c t u r a l p a t c h i s o l a t i o n o n s u m m e d i n flu e n c e o f s i z e a n d s p a t i a l p a t c h o b s e r v a t i o n a l ,2y rA u l t a n d 2a r r a n g e m e n t o f n e i g hb o r i n g p a tc h e sc o m m u n i t y s t r u c t u r e a nd p o p u l a t i o n J o h n s o n 1998d e n s i t y e x p e r i m e n t ,l i v e -t r a p p i n g ,13w k ,3e f f e c t o n d i s p e r s a l d i s t a n c e s a n d s p a t i a l p r e s e n c e /a b s e n c e o f c o r r i d o r s l a n d s c a p eB j o r n s t a d e t a l .3a g g r e g a t i o n g e n e r a t i o n 1998l a n d s c a p e ,10e x p e r i m e n tp e r c e n t o f e q u a l l y s p a c e d s t r a i g h t l i n e s 4C o l l i n g e a n d e f f e c t o f s t r u c t u r a l c o n n e c t i v i t y m ×10mm e a s u r e m e n t o n i n s e c t d e n s i t y ,r i c h n e s s ,F o r m a n 1998c o v e r i n g h a b i t a t w i t h i n a l a nd s c a pe a n d c o m m u n i t y s t r u c t u r e d i s c u s s i o nr a t i o n a l e o n t h e q u a n t i fic a t i o n o f l a n d s c a p es t r u c t u r a l p a t c h i s o l a t i o n D a v i d s o n 19985l a n d s c a p e f r a g m e n t a t i o n l a n d s c a p em o v e m e n t o f w a t e r b i r d s a m o n g h a b i t a t d i s c u s s i o nH a i g e t a l .1998r a t i o n a l e o n t h e i m p o r t a n c e o f f u n c t i o n a l 6p a t c h e s c o n n e c t i v i t y f o r w a t e r b i r d c o n s e r v a t i o n s p a t i a l l y e x p l i c i t s i m u l a t i o n m o d e l ,25y rH e n e i n e t a l .p r e s e n c e ,a b s e n c e a n d q u a l i t y o f f e n c e r o w s 7e f f e c t s o n p o p u l a t i o n s u r v i v a l l a n d s c a p ei n s i m u l a t e d l a n d s c a p e 1998e f f e c t o f s t r u c t u r a l a n d f u n c t i o n a l 8l a n d s c a p ee x p e r i m e n t ,o n e s e a s o nP e t i t a n d B u r e l d i s t a n c e s (e u c l i d i a n ,a l o n g h e d g e r o w s a n d ,w e i g h t e d b y m o v e m e n t i n t e n s i t y a n d c o n n e c t i v i t y o n s p e c i e s ’l o c a l a b u n d a n c e 1998bm o r t a l i t y i n d i f f e r e n t h a b i t a t t y p e s )b e t w e e n s a m p l e s i t e s 9l a n d s c a p ee x p e r i m e n t ,o n e s e a s o n‘‘f u n c t i o n a l d i s t a n c e ’’(w e i g h t e d b y P e t i t a n d B u r e l e f f e c t o f f u n c t i o n a l c o n n e c t i v i t y o n 1998am o v e m e n t i n t e n s i t y a n d m o r t a l i t y i n s p e c i e s ’l o c a l a b u n d a n c e d i f f e r e n t h a b i t a t t y p e s )l a n d s c a p em a n i p u l a t i v e m a r k -r e c a p t u r e e x p e r i m e n t ,e f f e c t s o f l a n d s c a p e s t r u c t u r e o n m o v e m e n t a b i l i t y o f d a m s e l fli e s t h r o u g h 10P i t h e r a n d d i f f e r e n t h a b i t a t t y p e s m o v e m e n t f r e q u e n c i e s o n e s e a s o n T a y l o r 1998e f f e c t o f s t r u c t u r a l c o n n e c t i v i t y o n l a n d s c a p eG I S b a s e d p o p u l a t i o n d y n a m i c s m o d e l n e a r e s t n e i g h b o r d i s t a n c e (c o m b i n e d w i t h 11R o o t 1998d i s pe r s a lf r e q u e n c y d i s t r i b u t i o n )b e t w e e n (m e t a )p o p u l a t i o n s i z e (R A M A S )h a b i t a t p a t c h e s 12p a t c hv e g e t a t i o n s u r v e ya m o u n t o f f o r e s t h ab i t a t a r o u n d p a tc h e s e f f e c t o f s t r u c t u r a l p a t c h i s o l a t i o n o n G r a s h o f b o kd a m 1997w i t h i n t h r e e z o n e s u p t o 1000m z o o c h o r o u s a n d a n e m o c h o r o u s p l a n t s p e c i e s l a n d s c a p es t a t i c o p t i m i z a t i o n a n d s i m u l a t i o n m o d e lp o p u l a t i o n a b u n d a n c e r e l a t i o n s h i p 13H o f a n d c o n n e c t i v i t y m e a s u r e a s s u m e d t o b e b e t w e e n a d j a c e n t c e l l s i n a g r i d m o d e l s p a t i a l l i m i t a t i o n f a c t o r R a p h a e l 1997c o n n e c t i v i t y c o m p o n e n t s :a )d e g r e e o f r a t i o n a l e o n t h e e f f e c t o f c o n n e c t i v i t y o n l a n d s c a p ec o n c e p t u a l m ode l ,d i s c u s s i o n14M e t z g e r a n d h a b i t a t p e r c o l a t i o n ,b )c o r r i d o r a n d b i o d i v e r s i t y D e ´c a m p s 1997s t e p p i n g s t o n e n e t w o r k s ,c )m a t r i x p e r m e a b i l i t y e f f e c t o n l o c a l b i r d c o m m u n i t y (s p e c i e s S c h m i e g e l o w e t p a t c he x p e r i m e n t ,1y rc o r r id o r s (r i p a r i a n b u f fe r s t r i p s )b e t w e e n 15f o r e s t f r ag m e n t s a b u n d a n c e s )a l .1997e f f e c t s o f s i m u l a t e d l a n d s c a p e ch a n g e s o n p r o xi m i t y i n d e x -s u m m a r i z e d (p a t c h p a t c hq u a n t i fic a t i o n o f s p a t i a l p a t t e r n i n G I SS p e t i c h e t a l .161997m a p ss t r u c t u r a l p a t c h i s o l a t i o n (p r o x i m i t y )a r e a /d i s t a n c e t o f o c a l p a t c h )r e l a t i o n s h i p f o r a l l p a t c h e s l o c a t e d w i t h i n r e c t a n g u l a r b u f f e r z o n e a r o u n d f o c a l p a t c h e s t i m a t i o n o f e f f e c t s o n s p e c i a l i s t l a n d s c a p ec o n c e p t u a l m ode li n t r i n s i c (j u x t a p o s i t i o n o f s i m i l a r h a b i t a t )T i e b o u t a n d 17c o l o n i z i n g a b i l i t y a nde x t r i n s i c (c o r r i d o r )c o n n e c t i v i t y A n d e r s o n 1997W i t h e t a l .ef f e c t o f l a n d s c a p e s p a t i a l s t r u c t u r e o n a v e r ag e d i s t a n c e b e t w e e n t w o s i t e s o f a l a n d s c a p e r a n d o m w a l k s i m u l a t i o n m o d e l o n 18n e u t r a l (r a n d o m a n d f r a c t a l )l a n d s c a p e 1997g r i d b e l o n g i n g t o t h e s a m e (p e r c o l a t i o n )p e r c o l a t i o n t h r e s h o l d a n d p o p u l a t i o n s ’s p a t i a l d i s t r i b u t i o nm a p sc l u s t e r ,p o p u l a t i o n s ’s p a t i a ld i s t r i b u t i o n10OIKOS 90:1(2000)T a b l e 1.(C o n t i n u e d )S p a t i a l s c a l e S t u d y t y p e a n d d u r a t i o nS t u d yN o .M e a s u r e m e n t /u s a g e o f c o n n e c t i v i t yC o m m e n t s /s t u d y t a r g e t p a t c h (c o r r i d o r )e x p e r i m e n t ,3m oA n d r e a s s e n e t a l .19s t r u c t u r a l d i s c o n t i n u i t i e s i n c o r r i d o r s e f f e c t s o n m o v e m e n t r a t e s 1996b e f f e c t s o n m o v e m e n t r a t e s p a t c h (c o r r i d o r )w i d t h o f c o r r i d o r s e x p e r i m e n t ,3m oA n d r e a s s e n e t a l .201996a l a n d s c a p e p h y s i c a l c o n n e c t i o n b e t w e e n p a t c h e s m e t a p o p u l a t i o n m o d e lH e s s 1996e f f e c t o n r e c o l o n i z a t i o n a n d e x t i n c t i o n 21(c o r r i d o r s )r a t e e f f e c t o f f u n c t i o n a l p a t c h i s o l a t i o n o n p a t c h h a b i t a t i s o l a t i o n b a s e d o n d i s p e r s a l o b s e r v a t i o n a l ,2y rH j e r m a n n a n d 22s p e c i e s p a t c h o c c u p a n c y d i s t a n c e d i s t r i b u t i o n s a n d n e g a t i v e I m s 1996e x p o n e n t i a l d i s p e r s a l f u n c t i o n e f f e c t o n p o p u l a t i o n m e a n s a n d 23p a t c h o p t i m i z a t i o n m o d e lb e t w e e n -p a tc h m o v e m e n t p r o b a b i l i t y H o f a nd F l a t he r v a r i a n c e s 1996d e p e n d e n t o n a )s p e c i e s d i s p e r s a l c a p a b i l i t y ,b )h a r s h n e s s of i n t e r -p a t c h e n v i r o n m e n t ,c )i n t e r -p a t c h d i s t a n c e e x p e r i m e n t ,1y rL e c o m t e a n d s i m u l a t e d p r e s e n c e /a b s e n c e o f 24e f f e c t s o n i n t e r -p a t c h d i s p e r s a l p a t c h C l o b e r t 1996c o r r i d o r s i n a n e x p e r i m e n t a l l a n d s c a p e p a t c h o b s e r v a t i o n a l ,1y rt o t a l l e n g t h o f h e d g e s i n a 0.5-k m P a i l l a t a n d B u t e t e f f e c t o f s t r u c t u r a l p a t c h i s o l a t i o n o n 25r a d i u s a r o u n d a s a m p l i n g p l o t (p a t c h )s p e c i e s a b u n d a n c e a n d flu c t u a t i o n s 1996e f f e c t o f r e a l l a n d s c a p e s t r u c t u r e o n l a n d s c a p e G I S -r e l a t e d r a n d o m w a l k s i m u l a t i o n m o d e l26S c h i p p e r s e t a l .m o v e m e n t p r o b a b i l i t i e s b e t w e e n a l l f u n c t i o n a l c o n n e c t i v i t y p a i r s o f h a b i t a t p a t c h e s 1996G I S -r e l a t e d r a n d o m w a l k s i m u l a t i o n m o d e ld i s pe r s a l s u c c e s s r a t e ,f r a c t i o n o f S c h u m a k e r 1996e f f e c t o f l a n d s c a p e s t r u c t u r e o n 27l a n d s c a p e f u n c t i o n a l c o n n e c t i v i t y i n d i v i d u a l s t h a t l o c a t e d n e w t e r r i t o r i e s p r e s e n c e /a b s e n c e o f c o r r i d o r s i n e f f e c t o n m e t a p o p u l a t i o n p e r s i s t e n c e S w a r t a n d L a w e s l a n d s c a p e 28m o d e lm e t a p o p u l a t i o n m o d e l 1996G I S -r e l a t e d r a n d o m w a l k a n d p o p u l a t i o n d y n a m i c s 29D e m e r s e t a l .l a n d s c a p e e f f e c t o f r e a l l a n d s c a p e s t r u c t u r e o n d i s p e r s a l (c o l o n i z a t i o n )s u c c e s s s i m u l a t i o n m o d e l f u n c t i o n a l c o n n e c t i v i t y 1995l a n d s c a p e o b s e r v a t i o n a l ,3y rp r e s e n c e /a b s e n c e o f c o r r i d o r s a n d /o r 30e f f e c t o n m o v e m e n t r a t e s a n d d i s t a n c e s A r n o l d e t a l .1993s t e p p i n g s t o n e s s t a t i c o p t i m i z a t i o n m o d e ll a n d s c a p e o p t i m i z a t i o n o f h a b i t a t p l a c e m e n t p r o b a b i l i s t i c ,d i s t a n c e d e p e n d e n t H o f a n d J o y c e 31i s o l a t i o n o f a c e l l i n a g r i d m o d e l 1993d e g r e e t o w h i c h t h e l a n d s c a p e l a n d s c a p e c o n c e p t u a l d i s c u s s i o nT a y l o r e t a l .199332d e fin i t i o n o f f u n c t i o n a l c o n n e c t i v i t y f a c i l i t a t e s o r i m p e d e s m o v e m e n t a m o n g r e s o u r c e p a t c h e s e f f e c t o f s c a l e o f c l u s t e r i n g o n s e a r c h t i m e -n u m b e r o f m o v e m e n t l a n d s c a p e r a n d o m w a l k s i m u l a t i o n m o d e l o n h i e r a r c h i c a l ,n e u t r a l 33D o a k e t a l .1992l a n d s c a p e m a p ss t e p s r e q u i r e d t o fin d a n e w h a b i t a t f u n c t i o n a l c o n n e c t i v i t y p a t c hpatches.Research is needed to determine what,if any, simple measures of landscape structure can be used as measures of landscape connectivity.Patch isolation or landscape connectivity?Patch isolation is determined by the rate of immigration into the patch;the lower the immigration rate,the more isolated is the patch.Immigration rate depends on(1) the amount of occupied habitat surrounding the focal patch,(2)the number of emigrants leaving the sur-rounding habitat,(3)the nature of the intervening matrix,(4)the movement and perceptual abilities of the organism,and(5)the mortality risk of dispersers (Wiens et al.1993).Since(1)and(3)are landscape structural features and(4)and(5)are the organisms’responses to landscape structure,patch isolation de-pends on‘‘the degree to which the landscape facilitates or impedes movement...’’(Taylor et al.1993).Patch isolation is therefore imbedded within the concept of landscape connectivity.In fact,landscape connectivity is essentially equivalent to the inverse of the average degree of patch isolation over the landscape;a land-scape including mostly patches with a high degree of isolation will be less connected than vice versa.Five of the33studies we reviewed equated patch isolation with connectivity(Hjermann and Ims1996, Paillat and Butet1996,Grashofbokdam1997,Spetich et al.1997,Ault and Johnson1998).Even though patch isolation is clearly part of landscape connectivity (above),none of these studies estimated immigration rates into patches.Rather,they related a species’abun-dance or presence/absence in a patch to structural attributes of the surrounding landscape,such as dis-tance to the nearest occupied patch,or amount of habitat in a circle surrounding the patch.Such studies may reveal the relative importance of local patch vs surrounding landscape effects.However,they do not directly contribute to determining landscape connectiv-ity,because they do not actually determine rates of movement among patches.Corridors or connectivity?Corridors are narrow,continuous strips of habitat that structurally connect two otherwise non-contiguous habitat patches.The corridor concept(e.g.,Forman 1983,Bennett1990,Merriam1991,Saunders and Hobbs1991,Lindenmayer and Nix1993,Merriam and Saunders1993,Bonner1994,Dawson1994,Rosenberg et al.1997,Tischendorf1997a)originated from the generalized assumption that organisms do not venture into non-habitat.Under this assumption,addition of any habitat to a landscape increases the ability of organisms to move.Corridors in a landscape may therefore be a component of its connectivity if they promote movement among habitat patches,but they do not determine its connectivity.The degree to which corridors contribute to landscape connectivity depends on the nature of the corridors,the nature of the matrix and the response of the organism to both(Rosenberg et al.1997,Beier and Noss1998).Six of the reviewed studies equated the term connec-tivity with the presence/absence of corridors(Hess 1996,Lecomte and Clobert1996,Swart and Lawes 1996,Schmiegelow et al.1997,Andreassen et al.1998, Bjornstad et al.1998),and two studies associated con-nectivity with corridor width(Andreassen et al.1996a) or corridor continuity(Andreassen et al.1996b).The studies investigated(1)what features of a corridorFig.1.Classification of the33reviewed studiesaccording to study type(a),year of publication(b),andusage of the termconnectivity(c).OIKOS90:1(2000)11determine its use by the organism,(2)space-use of organisms as a function of corridor presence/absence, and(3)population or community responses to corridors, e.g.,species richness,diversity or abundance.None of the studies explicitly recognized that corridors are only a component of the concept of landscape connectivity;they actually equated the connecting function of corridors with connectivity.Measurements of connectivityIn this section we review studies that quantified connec-tivity or key components of it.Recall that connectivity is defined as the degree to which the landscape facilitates or impedes movement among resource patches.Only four of the studies(Doak et al.1992,Demers et al.1995, Schippers et al.1996,Schumaker1996)measured move-ments among resource patches over the entire landscape and actually quantified connectivity in accordance with its definition.All of these were modeling studies and were based on simulated movements across heterogeneous landscapes.We also reviewfive other studies which we think made an important contribution toward the con-cept of landscape connectivity(as explained below),even though they did not measure movement among resource patches directly(Arnold et al.1993,With et al.1997,Petit and Burel1998a,b,Pither and Taylor1998). Modeling studiesDispersal successDispersal success is usually defined as the proportion of individuals that successfully immigrate into a new habitat patch during the course of a simulation run.Three of the modeling studies quantified connectivity using dispersal success.Schippers et al.(1996)(no.26in Table1)simulated the badger’s(Meles meles)response(movement proba-bility and mortality risk)to landscape structure using a classified GIS grid map and empirical expertise.Move-ment probabilities between cells were derived by compar-ing the quality(for badger use)of adjacent cells.Higher quality cells attracted moving individuals.Mortality rates were higher in low-quality cells.The number of simulated movement steps corresponded to an estimated actual time of badger movement within a four-year period.The authors produced inter-patch transition probabilities and movement frequency maps(visits per grid cell),based on dispersal success.Schumaker(1996)(no.27in Table1)analyzed the potential of indices of landscape structure to predict dispersal success.He created landscape models in two ways:(1)sample landscapes were randomly drawn from a GIS data set to cover a range of different landscape configurations;(2)artificial landscape grids were created by randomly designating habitat cells.Cells of the grid represented territories.An individual-based correlated random walk model was used to simulate movements across the landscape.Individuals were released in a randomly selected50%of habitat territories,and were allowed to settle in any unoccupied territory,which then became unavailable to subsequent nd-scape boundaries reflected approaching individuals. Connectivity was measured as the mean fraction(over several runs)of individuals that successfully dispersed into new territories during the course of a simulation.The results revealed correlations between each of ten indices of landscape structure and dispersal success(connectiv-ity).Demers et al.(1995)(no.29in Table1)investigated the relationship between colonization success of edge-preferring organisms,and the amount and change of edge habitat,in real agricultural landscapes.A vector-based GIS data set containing fencerow and forest-edge cover-ages was used as a model landscape.Individuals were allowed to move only in suitable habitat after being dropped at random points across the landscape.Individ-uals could cross inhospitable habitat(matrix)up to a maximum distance,after any edge habitat in the land-scape was successfully colonized.Occupied habitat could not be colonized by subsequent dispersers.The authors measured connectivity as the‘‘total length and area of hedgerow and forest edge colonized by the offspring of each successful virtual organism’’.The results showed higher connectivity in landscapes with more and longer overall edge habitat.Search timeOne paper(Doak et al.1992)(no.33in Table1)used search time to quantify connectivity.Search time is the number of movement steps individuals require tofind a new habitat patch.Doak et al.(1992)examined the effect of spatial scale on the success of dispersing individuals.An artificial landscape was modeled by a hierarchical grid of three layers(spatial scales).Clusters of habitat cells were created on different spatial scales.Virtual individuals were released in the habitat and followed a random walk until a new habitat patch(different from the origin)was ndscape boundaries acted as reflecting borders. For each individual the number of movement steps required tofind a new habitat patch(search time)was recorded.The mean and standard deviation over all individual search times were calculated and related to the scale of rge-scale clustering(few large patches)induced longer search times than small-scale clustering(more smaller patches)(see also Ruckelshaus et al.1997).Population spatial distributionWith et al.(1997)(no.18in Table1)investigated the effects of landscape spatial structure on(1)the probabil-12OIKOS90:1(2000)。

2022年考研考博-考博英语-湘潭大学考试预测题精选专练VII（附带答案）第1套一.综合题(共25题)1.单选题Lines of latitude run horizontally and are parallel to the Equator and lines of longitude run vertically. They（）at the North and South Poles.问题1选项A.convergeB.convokeC.convoyD.convulse【答案】A【解析】动词词义辨析。

根据句意‘纬线水平平行于赤道和经线相垂直。

它们在南北两极聚集。

’可知这里是说经线和纬线的位置，根据常识可知经线和纬线相互垂直，在南极和北极两个地方是聚集的，A选项converge"聚集，靠拢”；B选项convoke“召集”； C选项convoy“护送”；D选项convulse“震撼”。

根据句意确定A选项正确。

2.翻译题Like waistlines in many prosperous countries, cell phones are going XXL and some of their owners are struggling to tuck them in.Jeremy Roche, 47 years old, owns a Samsung Galaxy Note II phone that is about 75% larger than the original Apple Inc. iPhone, and roughly the size and heft of an extra-large Hershey’s chocolate bar, with about an inch nibbled off the end. It “did feel weird” at first to hold his big phone to his head for calls, he says, but now he loves his ample screen. After years of evolution from brick-size monstrosities into slim pocket devices, cell phones are going in reverse. South Korea's Samsung Electronics Co. is credited —or blamed 一 with bringing big phones back into the mainstream with devices like the original 5.3-inch Note, introduced outside the U.S. in late 2011.Some tech reviewers at the time derided the big phone as “silly”，and “a phone designed for giants.” But sales boomed, and other makers have followed with still-bigger “phablets”, as techiesarc beginning to call them—a cross between a phone and a tablet.Fares Fay ad, a 39-year-old consultant in Dubai, says he used to think a 3.5-inch cell phone screen was just right, until he tried the iPhone 5, which has a 4-inch screen. “I don’t believe I can go back to the slightly smaller screen,” Mr. Fay ad says,Some ergonomics experts wor ry lame phones could pose an injury risk. “As the stretch to reach all areas of the screen increases, we might start to see more serious repetitive stress injuries --- likely to the thumbs --- in larger touch-screen devices”, says Anthony Andre, a professor of human factors and ergonomics at San Jose State University.【答案】就像许多富裕国家居民的腰围一样，如今手机的尺寸也在逐渐增大，一些手机用户在费尽心思想把它们塞进自己的兜里。

《欧洲文化入门》知识点笔记1、There are many elements constituting(组成) European Culture.2、There are two major elements：Greco-Roman element and Judeo-Christian element.3、The richness(丰富性) of European Culture was created by Greco-Roman element and Judeo-Christian element.第一章1、The 5th century closed with civil war between Athens and Sparta.2、The economy of Athens rested on(依赖) an immense(无限的)amount of slave labour.3、Olympus mount, Revived in 1896(当代奥运会)4、Ancient Greece(古希腊)’s epics was created by Homer.5、They events of Homer’s own time. (错)(They are not about events of Homer’s own time, probably in the period 1200-1100 B.C.)6、The Homer’s epics consisted of Iliad and Odyssey.7、Agamemnon,Hector, Achilles are in Iliad.8、Odysseus and Penelope are in Odyssey.9、Odyssey(对其作品产生影响)—→James Joyoe’s Ulysses(描述一天的生活) In the 20th century.10、Drama in Ancient Greece was floured in the 5th century B.C.11、三大悲剧大师① Aeschylus《Prometheus Bound》—→模仿式作品Shelly《Prometheus Unbound》② Sophocles(之首)《Oedipus the King》—→ Freud’s “the Oedipus complex” (恋母情结)—→ David Herbert Lawrence’s《Sons and lovers》(劳伦斯)447页③ EuripidesA.《Trojan Women》B.He is the first writer of “problem plays”(社会问题剧) 在肖伯纳手中达到高潮，属于存在主义戏剧的人物C.Elizabeth Browning called him “Euripides human”(一个纯粹的人)D.Realism can be traced back(追溯到) to the Ancient Greece.To be specific(具体来说)，Euripides.12、The only representative of Greek comedy is Aristophanes. 18页Aristophanes writes about nature. —→浪漫主义湖畔派(The lakers)华兹华兹(新古典主义代表作家《格列夫游记》《大人国小人国》《温和的提议》用讽刺的写作手法)13、History (Historical writing)史学创作※“Father of History” —→ Herodotus —→ war(between Greeks and Persians)This war is called Peleponicion wars. 博罗奔泥撒，3只是陈述史实，并没有得出理论。

C H A P T E R O N EDissolved Organic Matter:Biogeochemistry,Dynamics,and Environmental Significance in SoilsNanthi S.Bolan,*,†Domy C.Adriano,‡Anitha Kunhikrishnan,*,†Trevor James,§Richard McDowell,}and Nicola Senesi #Contents1.Introduction32.Sources,Pools,and Fluxes of Dissolved Organic Matter in Soils 53.Properties and Chemical Composition of Dissolved Organic Matter in Soils133.1.Structural components133.2.Fulvic acid—The dominant component 153.3.Elemental composition204.Mechanisms Regulating Dynamics of Dissolved Organic Matter in Soils204.1.Sorption/complexation 234.2.Biodegradation 274.3.Photodegradation 284.4.Leaching295.Factors Influencing Dynamics of Dissolved Organic Matter in Soils 305.1.Vegetation and land use 315.2.Cultivation325.3.Soil amendments 335.4.Soil pH366.Environmental Significance of Dissolved Organic Matter in Soils 376.1.Soil aggregation and erosion control 376.2.Mobilization and export of nutrients386.3.Bioavailability and ecotoxicology of heavy metals43Advances in Agronomy,Volume 110#2011Elsevier Inc.ISSN 0065-2113,DOI:10.1016/B978-0-12-385531-2.00001-3All rights reserved.*Centre for Environmental Risk Assessment and Remediation (CERAR),University of South Australia,Australia {Cooperative Research Centre for Contaminants Assessment and Remediation of the Environment (CRC CARE),University of South Australia,Australia {University of Georgia,Savannah River Ecology Laboratory,Drawer E,Aiken,South Carolina,USA }AgResearch,Ruakura Research Centre,Hamilton,New Zealand }AgResearch,Invermay Agricultural Centre,Mosgiel,New Zealand #Department of Agroforestal and Environmental Biology and Chemistry,University of Bari,Bari,Italy 12Nanthi S.Bolan et al.6.4.Transformation and transport of organic contaminants506.5.Gaseous emission and atmospheric pollution587.Summary and Research Needs607.1.Macroscale(landscape to global)617.2.Microscale(water bodies and soil profile)617.3.Molecular scale(carbon fractions,organic acids,andmicroorganisms)61 Acknowledgments62 References62“Dissolved organic matter comprises only a small part of soil organicmatter;nevertheless,it affects many processes in soil and water includ-ing the most serious environmental problems like soil and waterpollution and global warming.”(Kalbitz and Kaiser,2003)AbstractDissolved organic matter(DOM)is defined as the organic matter fraction in solution that passes through a0.45m m filter.Although DOM is ubiquitous in terrestrial and aquatic ecosystems,it represents only a small proportion of the total organic matter in soil.However,DOM,being the most mobile and actively cycling organic matter fraction,influences a spectrum of biogeochemical pro-cesses in the aquatic and terrestrial environments.Biological fixation of atmo-spheric CO2during photosynthesis by higher plants is the primary driver of global carbon cycle.A major portion of the carbon in organic matter in the aquatic environment is derived from the transport of carbon produced in the terrestrial environment.However,much of the terrestrially produced DOM is consumed by microbes,photo degraded,or adsorbed in soils and sediments as it passes to the ocean.The majority of DOM in terrestrial and aquatic environ-ments is ultimately returned to atmosphere as CO2through microbial respira-tion,thereby renewing the atmospheric CO2reserve for photosynthesis.Dissolved organic matter plays a significant role in influencing the dynamics and interactions of nutrients and contaminants in soils and microbial functions, thereby serving as a sensitive indicator of shifts in ecological processes.This chapter aims to highlight knowledge on the production of DOM in soils under different management regimes,identify its sources and sinks,and integrate its dynamics with various soil processes.Understanding the significance of DOM in soil processes can enhance development of strategies to mitigate DOM-induced environmental impacts.This review encourages greater interactions between terrestrial and aquatic biogeochemists and ecologists,which is essential for unraveling the fundamental biogeochemical processes involved in the synthesis of DOM in terrestrial ecosystem,its subsequent transport to aquatic ecosystem, and its role in environmental sustainability,buffering of nutrients and pollutants (metal(loid)s and organics),and the net effect on the global carbon cycle.Dissolved Organic Matter31.IntroductionThe total organic matter(TOM)in terrestrial and aquatic environ-ments consists of two operationally defined phases:particulate organic matter(POM)and dissolved organic matter(DOM).For all practical purposes,DOM is defined as the organic matter fraction in solution that passes through a0.45m m filter(Thurman,1985;Zsolnay,2003).Some workers have used finer filter paper(i.e.,0.2m m)in an effort to separate “true”DOM from colloidal materials,but0.45m m filtration appears to be standard(Buffle et al.,1982;Dafner and Wangersky,2002).In some litera-ture,the term dissolved organic carbon(DOC)is used,which represents total organic carbon in solution that passes through a0.45m m filter (Zsolnay,2003).Since carbon represents the bulk of the elemental compo-sition of the organic matter(ca.67%),DOM is often quantified by its carbon content and referred to as DOC.In the case of studies involving soils,the term water-soluble organic matter(WSOM)or water-extractable organic matter(WEOM)is also used when measuring the fraction of the soil organic matter(SOM)extracted with water or dilute salt solution(e.g.,0.5 M K2SO4)that passes through a0.45m m filter(Bolan et al.,1996;Herbert et al.,1993).Recently,the distinction between POM and DOM in the marine environment is being replaced by the idea of an organic matter continuum of gel-like polymers,replete with colloids and crisscrossed by “transparent”polymer strings,sheets,and bundles,from a few to hundreds of micrometers—referred to as oceanic“dark matter”(Dafner and Wangersky,2002).Dissolved organic matter is ubiquitous in terrestrial and aquatic ecosys-tems,but represents only a small proportion of the total organic matter in soil(McGill et al.,1986).However,it is now widely recognized that because DOM is the most mobile and actively cycling organic matter fraction,it influences a myriad of biogeochemical processes in aquatic and terrestrial environments as well as key environmental parameters (Chantigny,2003;Kalbitz et al.,2000;McDowell,2003;Stevenson, 1994;Zsolnay,2003).Dissolved organic carbon has been identified as one of the major components responsible for determining the drinking water quality.For example,DOM leads to the formation of toxic disinfection by-products(DBPs),such as trihalomethanes,after reacting with disinfectants (e.g.,chlorine)during water treatment.Similarly,DOM can be related to bacterial proliferation within the drinking water distribution system.There-fore,the control of DOM has been identified as an important part of the operation of drinking water plants and distribution systems(Volk et al., 2002).In aquatic environments,the easily oxidizable compounds in the DOM can act as chemical and biological oxygen demand compounds, thereby depleting the oxygen concentration of aquifers and influencing4Nanthi S.Bolan et al. aquatic biota(Jones,1992).Dissolved organic carbon can act as a readily available carbon source for anaerobic soil organisms,thereby inducing the reduction of nitrate(denitrification)resulting in the release of green house gases,such as nitrous oxide(N2O)and nitric oxide(NO),which are implicated in ozone depletion(Siemens et al.,2003).Organic pesticides added to soil and aquifers are partitioned preferentially onto DOM,which can act as a vehicle for the movement of pesticide residues to groundwater (Barriuso et al.,1992).Similarly,the organic acids present in the DOM can act as chelating agents,thereby enhancing the mobilization of toxic heavy metals and metalloids[metal(loid)s](Antoniadis and Alloway,2002).The release and retention of DOM are the driving forces controlling a number of pedological processes including podzolization(Hedges,1987).Biological fixation of atmospheric CO2by higher plants during photo-synthesis is the primary driver of global carbon cycle.A major portion of the carbon in aquatic environments is derived from the transport of carbon produced on land.It has been estimated that worldwide about210Mt DOM and170Mt POM are transported annually to oceans from land. Carbon in the ocean is recognized as one of the three main reservoirs of organic material on the planet,equal to the carbon stored in terrestrial plants or soil humus(Hedges,1987).The terrestrially produced DOM is subject to microbial-and photodegradation and adsorption by soil and sediments.The majority of DOM in terrestrial and aquatic environments is returned to the atmosphere as CO2through microbial respiration,thereby ultimately replenishing the atmospheric CO2reserve for photosynthesis and reinvi-gorating the global carbon cycle.Dissolved organic carbon can be envisioned both as a link and bottle-neck among various ecological bined with its dynamic nature,this enables DOM to serve as a sensitive indicator of shifts in ecological processes,especially in aquatic systems.Recently,the significance of DOM in the terrestrial environment has been realized and attempts have been made to extend this knowledge to DOM dynamics in aquatic envir-onments.However,DOM dynamics on land are fundamentally different from those in water,where biomass of primary producers is relatively small, allochthonous sources of DOM are dominant,the surface area of reactive solid particles(i.e.,sediments)is smaller,and the fate of DOM is strongly influenced by photolysis and other light-mediated reactions.In contrast,the dynamics of DOM on land are largely controlled by its interactions with abiotically and biotically reactive solid components.Although there have been a number of reviews on the individual components of DOM in soils(e.g.,sources and sink—Kalbitz et al. (2000);microbial degradation—Marschner and Kalbitz(2003);sorption by soils—Kaiser et al.(1996)),there has been no comprehensive review linking the dynamics of DOM to its environmental significance.This chapter aims to elaborate on the production and degradation of DOM inDissolved Organic Matter5 soils under different landscape conditions,identify its sources and sinks,and integrate its dynamics with environmental impacts.Understanding the long-term control on DOM production and flux in soils will be particularly important in predicting the effects of various environmental changes and management practices on soil carbon dynamics.Improved knowledge on the environmental significance of DOM can enhance the development of strategies to mitigate DOM-induced environmental impacts.It is hoped that this chapter will encourage greater interaction between terrestrial and aquatic biogeochemists and ecologists and stimulate the unraveling of fundamental biogeochemical processes involved in the synthesis and trans-port of DOM in terrestrial and aquatic ecosystems.2.Sources,Pools,and Fluxes of DissolvedOrganic Matter in SoilsNearly all DOM in soils comes from photosynthesis.This represents the various C pools including recent photosynthates,such as leaf litter, throughfall and stemflow(in the case of forest ecosystems),root exudates, and decaying fine roots,as well as decomposition and metabolic by-pro-ducts and leachates of older,microbiologically processed SOM(Figure1) (Guggenberger,et al.,1994a;McDowell,2003;McDowell,et al.,1998). The majority of DOM in soils and aquifers originates from the solubilization of SOM accumulated through vegetation and the addition of biological waste materials(Guggenberger,et al.,1994b;McDowell,2003;McDowell, et al.,1998;Tate and Meyer,1983).The addition of biological waste materials,such as poultry and animal manures and sewage sludges,increases the amount of DOM in soils either by acting as a source of DOM or by enhancing the solubilization of the SOM.Most biological waste materials of plant origin contain large amounts of DOM(Table1)and the addition of certain organic manures such as poultry manure increases the pH and thereby enhances the solubilization of SOM(Schindler et al.,1992).The concentrations of DOM in soils and aquifers are highly susceptible to changes induced by humans,such as cultivation,fire,clear-cutting, wetland drainage,acidic precipitation,eutrophication,and climate change (Kreutzweiser et al.,2008;Laudon et al.,2009;Martinez-Mena et al.,2008; Mattsson et al.,2009;Yallop and Clutterbuck,2009).Dissolved organic matter in environmental samples,such as soils and manures,is often extracted with water or dilute aqueous salt solutions.Various methods have been used to measure the concentration of DOM in extracts (Table2).These methods are grouped into three categories(Moore, 1985;Sharp et al.,2004;Stewart and Wetzel,1981;Tue-Ngeun et al., 2005).The most frequently used method involves the measurement ofabsorption of light by the DOM using a spectrophotometer (Stewart and Wetzel,1981).The second method involves wet oxidation of samples containing DOM and the subsequent measurement of the CO 2released or the amount of oxidant consumed (Ciavatta et al.,1991).This method is often referred to as chemical oxygen demand (COD).Dichromates or permanganates are the most common oxidizing agents used in the wet oxidation of DOM,and the amount of oxidant consumed in the oxidation of DOM is measured either by titration with a reducing agent or by calorimetric methods.The third method involves dry oxidation of DOM to CO 2at high temperature in the presence of a stream of oxygen.The amount of CO 2produced is measured either by infrared (IR)detector or by titration after absorbing in an alkali,or by weight gain after absorbing in ascarite (Bremner and Tabatabai,1971).The most commonly used dry combustion techniques include LECO TM combustion and total organic carbon (TOC)analyzer.B horizonA horizonDOMDOMLitter layer Crop residueC horizonAquiferAgricultural soilForest soil 1111101099886677CO 2CO 2PhotosynthesisPhotosynthesis554433212Parent/geologicmaterialFigure 1Pathways of inputs and outputs of dissolved organic matter (DOM)in forest and agricultural soils.Inputs:1,throughfall and stemflow;2,root exudates;3,microbial lysis;4,humification;5,litter/and crop residue decomposition;6,organic amendments;outputs;7,microbial degradation;8,microbial assimilation;9,lateral flow;10,sorp-tion;11,leaching.6Nanthi S.Bolan et al.Plant litter and humus are the most important sources of DOM in soil,which is confirmed by both field and laboratory (including greenhouse)studies (Kalbitz et al.,2000;Kalbitz et al.,2007;Muller et al.,2009;Table 1Sources of dissolved organic matter input to soilsSourcesTotal organic matter (g C kg À1)Dissolvedorganic matterReference(g C kg À1)(%of total organic matter)Pasture leys Brome grass 13.30.0410.31Shen et al .(2008)Clover 15.10.0390.26Shen et al .(2008)Crowtoe10.40.0360.35Shen et al .(2008)Lucerne Cv.Longdong 11.40.0380.32Shen et al .(2008)Lucerne Cv.Saditi 10.90.0360.33Shen et al .(2008)Sainfoin 13.80.0400.29Shen et al .(2008)Sweet pea 10.20.0340.33Shen et al .(2008)SoilForest soil—litter leachate 60.00.0260.04Jaffrain et al.(2007)Arable soil12.00.150 1.25Gonet et al.(2008)Soil under bermuda grass turf 8.100.300 3.70Provin et al.(2008)Pasture soil 32.0 1.02 3.18Bolan et al.(1996)Pasture soil82.5 3.12 3.80Bolan et al.(1996)Organic amendments Sewage sludge 420 2.420.58Hanc et al.(2009)Sewage sludge 321 6.00 1.87Bolan et al.(1996)Paper sludge 2817.19 2.56Bolan et al.(1996)Poultry manure 4258.18 1.92Bolan et al.(1996)Poultry litter a37775.720.1Guo et al.(2009)Mushroom compost 3857.10 1.84Bolan et al.(1996)Fresh spent mushroom substrate28813346.2Marin-Benito et al.(2009)Composted spentmushroom substrate 27443.415.8Marin-Benito et al.(2009)Separated cow manure 4569.80 2.15Zmora-Nahuma et al.(2005)Poultry manure 4258.18 1.92Bolan et al.(1996)Pig manure2966.132.07Bolan et al.(1996)aBisulfate amended,phytase-diet Delmarva poultry litter.Dissolved Organic Matter 7Table2Selected references on methods of extraction and analysis of DOM in environmental samplesSamples Extraction of DOM Measurement of DOM ReferenceVolcanic ash soils Soil solutions collected by centrifugation ofcores at7200rpm;filtration(0.45m mfilters)DOC by Shimadzu TOC-5000analyzerKawahigashi et al.(2003)Peat—moorsh soil Soil samples were crushed an passed througha1mm sieve,then heated in a redistilledwater at100 C for2h under a reflexcondenser;filtration(0.45m mfilters)DOC by Shimadzu TOC5050A analyzerSzajdak et al.(2007)Soils(medial,amorphic thermic,Humic Haploxerands)Extraction with0.5mol LÀ1K2SO4solution1:5(w/v);filtration(AdvantecMFS Nº5C paper).TOC by combustion at675 Cin an analyzer(Shimadzu—model TOC-V CPN)Undurraga et al.(2009)Moss,litter and topsoil (0–5cm)Aqueous samples were estimated for DOCby oxidation of the sample with asulfochromic mixture(4.9g dmÀ3K2Cr2O7and H2SO4,1:1,w/w)withcolorimetric detection of the reduced Cr3þColorimeter KFK-3at590nm Prokushkin et al.(2006)Soil solutions from forested watersheds of North Carolina Samples werefiltered through a WhatmanG/F glassfiberfilters.Wet combustion persulfatedigestion followed byTOC analyzerQualls and Haines(1991)Organic fertilizer Extracted DOC by0.01M CaCl2solutionwith a solid to solution ratio of1:10(w/v),mixed for30min at200rpm;filtration(0.45m mfilter)Shimadzu TOC-5000ATOC analyzerLi et al.(2005)Soil solution and stream waters along a natural soil catena Soil solution collected by tension-freelysimetersDOC by infrared detectionfollowing persulfateoxidationPalmer et al.(2004)Liquid and solid sludge,farm slurry,fermented straw,soil, and drainage water Water extraction followed by centrifugation(40,000Âg)andfiltration(0.45m mfilter)Dry combustion(DhormannCarbon Analyzer DC-80)Barriuso et al.(1992)Soils,peat extract,sludge,pig and poultry manure and mushroom compost Extracted with water(1:3solid:solution ratio);centrifugation(12,000rpm)andfiltration(0.45m mfilter)Wet chemical oxidation withdichromate followed byback titrationBaskaran et al.(1996)Soil(Entic Haplothord)Extraction with deionized water(1:10solid:solution ratio);filtered through0.45m mpolysulfore membrane Dry combustion(TOCanalyzer Shimadzu5050)Kaiser et al.(1996)Pig manure Extracted with water(1:3solid:solution ratio);shaken at200rpm for16h at4o C;centrifugation(12,000rpm)andfiltration(0.45m mfilter)DOC by Shimadzu TOC-5000A TOC analyzerCheng and Wong(2006)Cow manure slurryfiltered through0.45m m polysulforemembrane TOC analyzer using UVabsorbanceAguilera et al.(2009)Sewage sludge DOC was extracted in a soil:water ratio of1:10(w/v)after1h agitation.Wet combustion withchromate followed by backtitrationGasco´and Lobo(2007)River water Natural water from riverfiltered by0.22m mfilter DOC by wet oxidation TOCanalyzerKrachler et al.(2005)Peat water Peat waterfiltered through0.45m mmembranefilters DOC was analyzed using ahigh-temperature catalyticoxidation method(Dohrman DC-190analyzer)Rixen et al.(2008)River water Filtered through0.7m m glassfiberfilter In situ optical technologyusingfluorescenceSpencer et al.(2007)(continued)Table2(continued)Samples Extraction of DOM Measurement of DOM ReferenceSea water Filtered through0.45m m polysulforemembrane High-temperaturecombustion instrument tomeasure isotopecomposition of DOCLang et al.(2007)Freshwater Filtered through0.7m m glassfiberfilter Acid-peroxydisulfatedigestion and high-temperature catalyticoxidation(HTCO)withUV detectionTue-Ngeun et al.(2005) Effluent water–In situ UV spectrophotometer Rieger et al.(2004)Groundwater,lake water, and effluent –High-performance liquidchromatography-sizeexclusion chromatography-UVAfluorescence systemHer et al.(2003)Sea water and effluent Filtered through0.7m m glassfiberfilter Measurement of carbonatomic emission intensity ininductively coupled plasmaatomic emissionspectrometry(ICP-OES)Maestre et al.(2003)Lake water Water samplesfiltered using precombustedGF/Ffilters TOC analyzer(TOC5000;Shimadzu)Ishikawa et al.(2006)Soil solution and stream water from forested catchments Samples werefiltered through0.45m mfiltersDOC by Shimadzu TOC5050A analyzerVestin et al.(2008)Dissolved Organic Matter11 Sanderman et al.,2008).In forest ecosystems,which are the most intensively studied with regard to C cycling and its associated DOM dynamics,the canopy and forest floor layers are the primary sources of DOM(Kaiser et al., 1996;Kalbitz et al.,2007;Park and Matzner,2003).However,it is still unclear whether DOM originates primarily from recently deposited litter or from relatively stable organic matter in the deeper part of the organic horizon(Kalbitz et al.,2007).In a temperate,deciduous forest,the source of DOM leaching from the forest floor(O layer)is generally a water-soluble material from freshly fallen leaf litter and throughfall(Kalbitz et al.,2007;Qualls et al.,1991).Appar-ently all of the DOM and dissolved organic N(DON)could have origi-nated from the Oi(freshly fallen litter)and Oe(partially decomposed litter) horizons.They further observed that,while about27%of the freshly shed litter C was soluble,only18.4%of the C input in litterfall was leached in solutions from the bottom of the forest floor.Virtually all the DOM leached from the forest floor appeared to have originated from the upper forest floor,with none coming from the lower forest floor—an indication of the role of this litter layer as a sink.The role of freshly deposited litter as DOM source was further corroborated by laboratory studies(Magill and Aber, 2000;Moore and Dalva,2001;Muller et al.,2009;Sanderman et al.,2008). Michalzik and Matzner(1999)found high fluxes of DOM from the Oi layer than from the Oe and Oa layers and indicated that the bottom organic layers acted instead as a sink rather than as a source of DOM.Logically,however, because of the more advanced state of decomposition,the bottom litter layers could produce more DOM than the surface layer.Indeed,Solinger et al.(2001)measured greater DOM fluxes out of the Oa than out of the Oi layer.Recently,Froberg et al.(2003)and Uselman et al.(2007)confirmed with14C data that the Oi layer is not a major source of DOM leached from the Oe layer.In a comprehensive synthesis of42case studies in temperate forests, Michalzik et al.(2001)observed that,although concentrations and fluxes differed widely among sites,the greatest concentrations of DOM(and DON)were generally observed in forest floor leachates from the A horizon and were heavily influenced by annual precipitation.However,somewhat surprisingly,there were no meaningful differences in DOM concentrations and fluxes in forest floor leachates between coniferous and hardwood sites. The flux of soluble organic compounds from throughfall and the litter layer could amount to1–19%of the total litterfall C flux and1–5%of the net primary productivity(Froberg et al.,2007;McDowell and Likens,1988; Qualls et al.,1991).Nearly one-third of the DOM leaving the bottom of the forest floor originated from throughfall and stemflow(Qualls et al.,1991; Uselman et al.,2007).Values for the potential solubility of litter in the field and in laboratory studies are in the5–25%range of the litter dry mass and 5–15%of the litter C content(Hagedorn and Machwitz,2007;McDowell12Nanthi S.Bolan et al. and Likens,1988;Muller et al.,2009;Sanderman et al.,2008;Zsolnay and Steindl,1991).In typical soils,DOM concentrations may decrease by50–90%from the surface organic layers to mineral subsoils(Cronan and Aiken,1985;Dosskey and Bertsch,1997;Worrall and Burt,2007).Similarly,fluxes of DOM in surface soil range from10to85g C mÀ2yrÀ1,decreasing to2–40g C mÀ2 yrÀ1in the subsoils(Neff and Asner,2001).In cultivated and pastoral soils,plant residues provide the major source of DOM,while in forest soils,litter and throughfall serve as the major source (Ghani et al.,2007;Laik et al.,2009).In forest soils,DOM represents a significant proportion of the total C budget.For example,Liu et al.(2002) calculated the total C budgets of Ontario’s forest ecosystems(excluding peat lands)to be12.65Pg(1015g),including1.70Pg in living biomass and10.95 Pg in DOM in soils.Koprivnjak and Moore(1992)determined DOM concentrations and fluxes in a small subarctic catchment,which is composed of an upland component with forest over mineral soils and peat land in the lower section.DOM concentrations were low(1–2mg LÀ1)in precipita-tion and increased in tree and shrub throughfall(17–150mg LÀ1),the leachate of the surface lichens and mosses(30mg LÀ1),and the soil A horizon(40mg LÀ1).Concentrations decreased in the B horizon(17mg LÀ1)and there was evidence of strong DOM adsorption by the subsoils.Khomutova et al.(2000)examined the production of organic matter in undisturbed soil monoliths of a deciduous forest,a pine plantation,and a pasture under constant temperature(20 C)and moisture.After20weeks of leaching with synthetic rain water at pH5,the cumulative values of DOM production followed:coniferous forest>deciduous forest>pasture,the difference being attributed to the nature of carbon compounds in the original residues.The residues from the coniferous forest were found to contain more labile organic components.Among ecosystems types,Zsolnay(1996)indicated that DOM tends to be greater in forest than agricultural soils:5–440mg LÀ1from the forest floor compared with0–70mg LÀ1from arable soils.Other studies have also indicated greater concentrations of DOM and concentrations in grasslands than in arable soils(Ghani et al.,2007;Gregorich et al.,2000;Haynes, 2000).In general,DOM concentration decreases in the order:forest floor> grassland A horizon>arable A horizon(Chantigny,2003).The rhizosphere is commonly associated with large C flux due to root decay and exudation(Muller et al.,2009;Uselman et al.,2007;Vogt et al., 1983).Microbial activity in the rhizosphere is enhanced by readily available organic substances that serve as an energy source for these organisms (Paterson et al.,2007;Phillips et al.,2008).Because of their turnover,soil microbial biomass is also considered as an important source of DOM in soils (Ghani et al.,2007;Steenwerth and Belina,2008;Williams and Edwards, 1993).Thus,microbial metabolites may represent a substantial proportionDissolved Organic Matter13 of the soil’s DOM.It may well be that the rate of DOM production and extent of DOM dynamics in soil is regulated by the rate of litter/residue incorporation in soils,kinetics of their decomposition,and various biotic and abiotic factors(Ghani et al.,2007;Kalbitz et al.,2000;Michalzik and Matzner,1999;Zech et al.,1996).In summary,the various C pools in an ecosystem represent the sources of DOM in soils.Due to their abundance,recently deposited litter and humus are considered the two most important sources of DOM in forest soils. Similarly,recently deposited crop residues and application of organic amendment such as biosolids and manures are the most important sources of DOM in arable soils.However,the role of root decay and/or exudates and microbial metabolites cannot be downplayed in both forested and arable ecosystems.3.Properties and Chemical Composition ofDissolved Organic Matter in Soils3.1.Structural componentsBecause DOM is a heterogeneous composite of soluble organic compounds arising from the decomposition of various carbonaceous materials of plant origin,including soluble microbial metabolites from the organic layers in the case of forest ecosystem,DOM constituents can be grouped into “labile”DOM and“recalcitrant”DOM(Marschner and Kalbitz,2003). Labile DOM consists mainly of simple carbohydrate compounds(i.e., glucose and fructose),low molecular weight(LMW)organic acids,amino sugars,and LMW proteins(Guggenberger et al.,1994b;Kaiser et al.,2001; Qualls and Haines,1992).Recalcitrant DOM consists of polysaccharides (i.e.,breakdown products of cellulose and hemicellulose)and other plant compounds,and/or microbially derived degradation products(Marschner and Kalbitz,2003)(Table3).Soil solution DOM consists of LMW carbox-ylic acids,amino acids,carbohydrates,and fulvic acids—the first comprising less than10%of total DOM in most soil solutions and the last(i.e.,fulvic acid)being typically the most abundant fractions of DOM(Strobel et al., 1999,2001;Thurman,1985;van Hees et al.,1996).Dissolved organic matter is separated into fractions based on solubility, molecular weight,and sorption chromatography.Fractionation of DOM by molecular size and sorption chromatography separate DOM according to properties(hydrophobic and hydrophilic)which regulate its interaction with organic contaminants and soil surfaces.The most common technique for the fractionation of aquatic DOM is based on its sorption to non-ionic and ion-exchange resins(Leenheer,1981).。

两级分化英语Navigating the Dichotomy: English in a World of DualitiesEnglish, once merely a tool for communication, now stands as a symbol of globalization's double-edged sword. Its ubiquity in both professional and personal spheres unveils a stark dichotomy: one of empowerment and exclusion, of cultural convergence and divergence. As we delve into the nuances of this linguistic landscape, it becomes evident that the bifurcation of English is not a mere happenstance but a reflection of broader socio-economic and geopolitical dynamics.On one end of the spectrum lies the allure of proficiencyin English, akin to possessing a golden ticket to the global arena. Those fluent in the language find themselves at a distinct advantage, unlocking access to a plethora of opportunities ranging from higher education in prestigious institutions to lucrative job prospects in multinational corporations. English proficiency becomes synonymous with upward mobility, enabling individuals to transcendgeographical and cultural boundaries with ease. Yet, this very proficiency erects barriers for those left behind, accentuating disparities within societies and perpetuating a cycle of inequality.The phenomenon of linguistic imperialism looms large, with English asserting its dominance in spheres far beyond its Anglophone origins. In the realms of academia and research, English serves as the lingua franca, relegating indigenous languages to the periphery and endangering linguistic diversity. This hegemonic imposition of English not only undermines the cultural heritage of non-native speakers but also reinforces a power dynamic where linguistic capital equates to social capital. Consequently, marginalized communities find themselves grappling with the erasure of their linguistic identity, caught in a struggle for preservation amidst the tide of anglicization.Moreover, the globalization of English engenders a paradoxical fusion of cultures while simultaneously exacerbating cultural homogenization. Through the medium of English, diverse narratives converge, facilitating cross-cultural exchange and fostering a sense of global interconnectedness. However, this very amalgamation often comes at the cost of cultural authenticity, as nuances and intricacies inherent to native languages are lost in translation. As English permeates various facets of life, from literature to entertainment, the line between cultural appreciation and appropriation blurs, raising questions about the commodification of identity in the global marketplace.The dichotomy of English extends beyond individual experiences to shape geopolitical landscapes and international relations. English proficiency serves as a barometer of a nation's global standing, influencing diplomatic negotiations and strategic alliances. Countries invest heavily in English education, viewing linguistic prowess as a means to assert soft power on the world stage. Consequently, the divide between English-speaking nations and non-English-speaking nations widens, perpetuating asymmetrical power dynamics and reinforcing existing hierarchies in the global order.In conclusion, the phenomenon of two-tiered differentiation in English reflects the multifaceted nature ofglobalization and its repercussions on language, culture, and society. As we navigate this linguistic dichotomy, itis imperative to recognize the inherent complexities and tread cautiously towards a future where linguisticdiversity is celebrated, and linguistic imperialism is dismantled. Only through concerted efforts to bridge the gap between the haves and the have-nots in the realm of English proficiency can we aspire towards a more inclusive and equitable global discourse.。

分离变量法英文Separation of VariablesThe separation of variables is a powerful mathematical technique used to solve a wide range of differential equations. This method is particularly useful for solving linear partial differential equations, where the dependent variable can be expressed as a product of functions of the independent variables. By breaking down the equation into simpler components, the separation of variables allows for the identification of solutions that satisfy the given boundary conditions.One of the key advantages of the separation of variables method is its ability to simplify complex partial differential equations into a set of ordinary differential equations. This approach is often used in various fields of science and engineering, including heat transfer, fluid dynamics, and quantum mechanics, where the underlying equations can be expressed in terms of multiple independent variables.To apply the separation of variables method, the first step is to identify the type of partial differential equation you are dealing with.This typically involves determining the number of independent variables and the order of the equation. Once the equation has been identified, the next step is to assume a solution in the form of a product of functions, each dependent on a single independent variable.For example, consider the following partial differential equation:∂u/∂t = ∂²u/∂x² + ∂²u/∂y²This is a second-order linear partial differential equation with two independent variables, x and y, and a dependent variable, u, that represents a function of both x and y, as well as time, t.To solve this equation using the separation of variables method, we assume that the solution can be expressed as:u(x, y, t) = X(x)Y(y)T(t)where X(x), Y(y), and T(t) are functions of the respective independent variables.By substituting this assumed solution into the original partial differential equation and rearranging the terms, we can obtain a set of ordinary differential equations for each of the functions X(x), Y(y),and T(t). These equations can then be solved independently, and the final solution is obtained by combining the individual solutions.The separation of variables method is not limited to linear partial differential equations. It can also be applied to nonlinear equations, though the process may be more involved. In these cases, the assumption of a product-form solution may still be valid, but the resulting ordinary differential equations may be more complex to solve.One important consideration when using the separation of variables method is the choice of the separation constants. These constants are introduced during the process of separating the variables and can have a significant impact on the final solution. The appropriate choice of separation constants is crucial to ensuring that the solution satisfies the given boundary conditions.In addition to its applications in solving differential equations, the separation of variables method has found use in various other areas of mathematics and physics. For example, it is commonly employed in the study of eigenvalue problems, where the separation of variables can lead to the identification of the eigenfunctions and eigenvalues of a system.Furthermore, the separation of variables technique is closely relatedto the method of variable separation, which is used to solve ordinary differential equations. The two methods share a common approach of breaking down a complex problem into simpler, manageable components.In conclusion, the separation of variables is a powerful and versatile mathematical technique that has been extensively used in various fields of study. Its ability to simplify complex partial differential equations and provide solutions that satisfy given boundary conditions makes it an invaluable tool in the arsenal of mathematical problem-solving.。

Cable Modeling Technique in Virtual Assembly for Satellite SystemLiu Yuan, Li Hui , Dong LiminSchool of Astronautics, Harbin Institute of TechnologyHarbin 150001, ChinaAbstract-At present, physical verification of cable assemblies is mainly through simulation assembly in actual project. However, it leads to problems of a long period of production design and high cost. Virtual assembly technology and the development of related technologies provides a new idea for solving problems in cable assembly wiring, and provides a new platform for integrated wiring system. The non-uniform cubic B-spline curve is used to interpolate key path points considering process demand. To reduce singular points in the interpolation curve generated with methods proposed, smoothing treatment towards cable centre line is carried out after calculation of cable curve. These technologies are important parts to design a comprehensive wiring automation software analysis system combined with the computer technology become necessary.Keywords-Virtual assembly, Cable assembly, Non-uniform cubic B-spline curve, Smoothing treatmentI.INTRODUCTIONCable, widely used in electromechanic products such as weapons and equipment, aircraft, automobile and computer is indispensable part of electromechanical system. It is the important component in transmission of current and signals. Cable assemblies wiring has a complicated process and is big difference to the quality of mechanical and electrical products. Cable wiring quality and assembly reliability directly affects product performance and reliability. At present, physical verification of cable assemblies is mainly through simulation assembly in actual project. However, it leads to problems of a long period of production design and high cost.The current cable assembly in complex products mainly depends on hand sampling in construction site. Non-standard assembly process, poor tolerance and low reliability between electrical connectors have become important factors influencing assembly quality of mechanical and electronic products. At present, the development of mechanical and electronic products in cable is usually divided into the following four processes. The first step is electrical diagram design. The second, design cable according to electrical logic diagram and form wiring harness. The third, wiring scheme and assembly process scheme are determined by repeatedly changing outfits of cables in product prototype. And the last one is cable installation. At this stage, assembly workers assemble cable according to cable assembly drawings in process card. With miniaturization, lightweight, high precision process of complex equipment of aircraft and light, machine, electricity integration development, the irrationality of cable path planning and non-standard assembly process have become one of the important reasons influencing product assembly quality.At present, many commercial software such as Pro/E, CATIA, provides the cable 3D modeling function modules. However, modeling operating modes provided by these modules are not intuitive and they cannot directly provided cable assemblies wiring interference detection. These will seriously hinder the wide application in the enterprise.Virtual assembly technology and the development of related technologies provides a new idea for solving problems in cable assembly wiring, and provides a new platform for integrated wiring system. To design a comprehensive wiring automation software analysis system combined with the computer technology becomes necessary.In research, a number of researchers have long devoted themselves to virtual assembly of cable[1-5]. Cable modeling technique in virtual assembly for satellite system is introduced in this paper.II.G ENERATION OF CABLE CENTRE LINE To complete the virtal cable assembly in satellite system, the primary task is to find an adaptive method in reprsenting the cable with the effective mathematical model. Choosing appropriate math function to describe cable centre line is one of key problems in establishing cable mathematical model. In this paper, the non-uniform cubic B-spline curve is choosen as the expression builder in cable generation for making full use of its advantage in curve expression. Each cable is generated by a series of key path points considering process demand. We suppose the key path points {}01,,,np p p. The non-uniform cubic B-spline curve ()up through the set of key path points is calculated, with a result()(0,1,,)iu i n∈=p p.At the first stage, the knot vector of ()up is calculated using a method of standard-chord-length parameterization used widely in Computer-Aided Geometric Design (CAGD). The knot vector calculated is U([]016,,,nu u u+=U)，in which [][]33,0,1nu u+∈，0123u u u u====and 34561n n n nu u u u++++====.The internal knot vector of the non-uniform cubic B-spline curve ()up is calculated with Hartley－Judd method as follows in which the parameter k equals to three.11111,1,2,,1i jj i k i i n s jjs k j s klu u i k k n l l−=−−+−=+=−−==+++∑∑∑(1)where 1jj j l −=−d dThe node values finally calculated are as follows.110(),1,2,,1k i j j n u u u u j k k n u −+==−=++=∑ (2)The control points for ()u p ,(0,1,,)j j m = d , where m is equal to 2n +, can be achieved as follows[6].111222222111m m m m m m a b c a b c a b c a b c −−−−−−⎡⎤⎢⎥⎢⎥⎢⎥⎢⎥⎢⎥⎢⎥⎣⎦11222211m m m m −−−−⎡⎤⎡⎤⎢⎥⎢⎥⎢⎥⎢⎥⎢⎥⎢⎥=⎢⎥⎢⎥⎢⎥⎢⎥⎢⎥⎢⎥⎣⎦⎣⎦d e d e d e d e (3) where()2212211231212321123121()(),2,3,,2()()i i i i i i i i i i i i i i i i i i i i i i i ii i i a b i m c +++++++++++++++++++−⎧Δ=⎪Δ+Δ+Δ⎪⎪ΔΔ+ΔΔΔ+Δ⎪=+=−⎪Δ+Δ+ΔΔ+Δ+Δ⎨⎪Δ⎪=⎪Δ+Δ+Δ⎪=Δ+Δ⎪⎩ e pand 1i i i u u +Δ=−.1111,,,a b c e and 1111,,,m m m m a b c −−−−ecan be given out consulting the Ref.[11]. 121,,,m − d d d can be calculated by Eq.(3). (0,1,,)j j m = d will be confirmed after a supposition00=d p and m n =d p . With knot vector U and control points (0,1,,)j j m = d , the non-uniform rational B-spline interpolation curve ()u p is confirmed.III. S MOOTHING TREATMENT OF CABLE CENTRE LINEThe interpolation curve generated with methods introduced in section 1 may have singular points, which can not meet curvatures requirements of the cable. So, smoothing treatment towards cable centre line will be carried out after calculation of cable curve.There are two ways to smooth the curve interpolating the cable. The comprehensive wiring automation softwarefor cable assembly wiring firstly judges the fairness of curve, then revises the bad points in the curve, and finally carrys out related operation towards the calculated curve in section 2. For curves of big deflection, energy methods are adopted and selected-point method is used for curves of small deflection.The basic principle of selected-point method according to the standards for local light, checking points time after time, is gradually finding out points not accord with the light of the conditions of the type of point (what say normally namely "bad point"), which in turn to bad point is revised. This process is carried out as a reciprocating modification operation, until the curve accords with the light of the criterion conditions.We suppose the given path points {1,2,,}i i n =P , and ()t p is a curve through the set of key path points. We project (1,2,,)i i n =P and ()t p to the plane XOY and the plane ZOX respectively. The fairing process will be carried out towards project curves.Supposing the relative curvature of ()t p at{1,2,,}i i n =P i k , we find out points meet thefollowing conditions.⎩⎨⎧<<+−0.0.11i i i i k k k k (4)There can be several points meet the conditions and they may be extreme points. We suppose)3(+i f and)3(−i f are the third derivatives of this curve at the i th path point.)3()3(max −+−=i i i f f N (5)Calculating all N values of the bad points, the point which corresponds the bigest N value is the one to be revise up at the front.Supposing the worst point ),(i i y x , this bad point will be eliminated and the remaining type point will be used to generate a new spline interpolation function structure. Using i x and the function generated, the value i Y will be calculated out. The distance between i Y and i y will be calculated out as follows.i i i L y Y =− (6)The value i y will be replace with i Y if the condition followed established. Inversely, i y will be replace withii iL y L ε+ (7)The energy methods are discussed in detail in this paper. We suppose the key path points {}01,,,n p p p . The non-uniform cubic B-spline curve through the set of key path points is ()u p . The path points after smoothing treatment is {1,2,,}i i n =q , and the interpolation curve is ()t q . The curve strain-energy of ()u p applied elastic force is shown by Eq.(8).221()()22n i i i i E k ds αβ==++∑⎰p q (8)We can find that the curve energy is consisted of two parts: strain energy of the curve and elasticity energy of the curve. Strain energy shows fairing performance of the curve and elasticity energy presents deviate degree of the new curve towards the original curve. And so, coefficient α is called smooth factor, and β approximation factor. We suppose curve ()t p expressed by 2,30()()n o o j j j t N t +==∑p d,and curve ()t q by 2,3()()n jj j t Nt +==∑q d , in which oj dand j d are called control points. ,3()oj N t and ,3()j N t are basis functions. There is a linear equation group shown by Eq.(9) with an assumption that 012(,,,)Tn +=D d d d .=AD C (9) In Eq.(5), coefficient matrix A is square matrix of3n +dimensional. And matrix elements ,i j a （0,1,,2i n =+ ；0,1,2j n =+） is calculated by Eq.(10). 32'''',,3,3,33,3310()()()()k k n n t i j i j k i k j K t k k a N t N t dt N t N t αβ++++===+∑∑⎰(10)i C , in matrix 012(,,,)n +=C C C C , is calculated by Eq.(11). ,330(),0,1,,n i k k i k k N t i n β+===∑C p (11) Knot values of curve()t p is put into the equation ()t q in turn and data points sequence (1,2,,)i i n =qis calculated. Then we calculate maximum values of(1,2,,)i i i L i n =−=p q , and compare them withmaximum tolerance ε. If there is a condition i L ε≤, the curve ()t qis the satisfied curve. Otherwise, with parameters /2,/4,/8αααα= , control points jd （0,1,,2j n =+ ）is calculated once more till it meetmaximum tolerance requirements.IV. S UMMARIESCable modeling technique in virtual assembly forsatellite system is introduced in this paper. The non-uniform cubic B-spline curve is used to interpolate key path points considering process demand. To reduce singular points in the interpolation curve generated with methods proposed, smoothing treatment towards cable centre line is carried out after calculation of cable curve. These technologies are important parts to design a comprehensive wiring automation software analysis system combined with the computer technology becomes necessary.REFERENCES[1] Caudell T P; Mizell D W. Augmented reality: an application ofheads-up display technology to manual manufacturing processes[J].Proc. IEEE Hawaii Int. Conference on System Sciences,1992, PP:635~643[2] LIU Jian-hua; WAN Bi-le; NING Ru-xin. 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