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Alkali and Alkaline Earth Metal Compounds:Core-Valence Basis Sets and Importance of Subvalence Correlation Mark A.Iron,Mikhal Oren,and Jan M.L.Martin Department of Organic Chemistry,Weizmann Institute of Science,76100Reh .ovot,Israel ?(Dated:Mol.Phys.,in press (W.G.Richards special issue))Abstract Core-valence basis sets for the alkali and alkaline earth metals Li,Be,Na,Mg,K,and Ca are proposed.The basis sets are validated by calculating spectroscopic constants of a variety of di-atomic molecules involving these elements.Neglect of (3s,3p )correlation in K and Ca compounds will lead to erratic results at best,and chemically nonsensical ones if chalcogens or halogens are present.The addition of low-exponent p functions to the K and Ca basis sets is essential for smooth convergence of molecular properties.Inclusion of inner-shell correlation is important for accurate spectroscopic constants and binding energies of all the compounds.In basis set extrapo-lation/convergence calculations,the explicit inclusion of alkali and alkaline earth metal subvalence correlation at all steps is essential for K and Ca,strongly recommended for Na,and optional for Li and Mg,while in Be compounds,an additive treatment in a separate ‘core correlation’step is probably su?cient.Consideration of (1s )inner-shell correlation energy in ?rst-row elements requires inclusion of (2s,2p )‘deep core’correlation energy in K and Ca for consistency.The latter requires special CCV n Z ‘deep core correlation’basis sets.For compounds involving Ca bound to electronegative elements,additional d functions in the basis set are strongly recommended.For optimal basis set convergence in such cases,we suggest the sequence CV(D+3d )Z,CV(T+2d )Z,CV(Q+d )Z,and CV5Z on calcium.
I.INTRODUCTION
The rate-determining step in accurate wavefunction ab initio calculations is the determi-nation of the correlation energy.Moderately reliable methods like CCSD(coupled cluster with all single and double substitutions[1])have theoretical CPU time scalings∝n2N4, where n and N represent the numbers of electrons and basis functions,respectively.For the CCSD(T)(i.e.,CCSD with a quasiperturbative estimate of the e?ect of connected triple substitutions[2])method—which has been termed the“gold standard of quantum chem-istry”(T.H.Dunning)—the corresponding scaling is∝n3N4.
For this reason,the idea of only including the‘chemically relevant’valence electrons in the correlation problem and constraining the inner-shell or‘core’orbitals to be doubly occupied gained currency early on.Bauschlicher et al.[3]were the?rst to propose a partitioning of the inner-shell correlation energy into a core-core(CC)component—involving excitations exclusively out of the inner-shell orbitals—and a core-valence(CV)component—involving simultaneous excitations out of the valence and inner-shell orbitals.While,at least in elements with a large core-valence gap(see below),the CC component can be expected to roughly cancel between a molecule and its separated atoms,the CV component may a?ect chemically relevant molecular properties to some degree.
Over time,it has become recognized that the inclusion of inner-shell correlation—even in?rst-row systems—is important for accurate binding energies(e.g.[4,5]),molecular geometries(e.g.[4]),and harmonic frequencies(e.g.[4]).The treatment of inner-shell cor-relation requires special basis sets which not only have additional radial?exibility,but also include‘hard’or‘tight’(i.e.,high-exponent)d,f,...functions in order to cover angular correlation from the inner-shell orbitals.Special basis sets of this type have been developed, such as the cc-pCV n Z(correlation consistent polarized core-valence n-tuple zeta)basis sets of Woon and Dunning[6]for B–Ne,the MT(Martin-Taylor[7])and MTsmall[8]basis sets for Li–Ar,the rather small G3large basis set[9]of Pople and coworkers for the main group elements of the?rst three rows,and very recently the cc-pwCV n Z(i.e.core-valence weighted cc-pCV n Z)basis sets of Peterson and Dunning[10]for B–Ne and Al–Ar.
While the CC+CV contribution to absolute correlation energies may rival or exceed the valence contribution,its di?erential contribution to the molecular binding energy is gener-ally small compared to the SCF and valence correlation contributions(typically less than
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1%for1st-row systems).For that reason—as well as the formidable cost of core corre-lation calculations—computational thermochemistry schemes(e.g.G3theory[9],W1/W2 theory[8,11])that account for inner-shell correlation generally treat the latter as a small additive contribution obtained with a relatively compact core correlation basis set.(The ?nding[8]that connected triple substitutions are surprisingly important for CV contribu-tions ensures that the core correlation step often is the rate-determining one for benchmark thermochemistry calculations,particularly beyond the?rst row of the Periodic Table.)Re-cently,some attempts have been made to replace the core correlation step by bond additivity approximations[12,and references therein],and promising results have been obtained[13]by means of core polarization potentials[14].
Despite repeated warnings in the literature against the practice(e.g.,by Taylor[15],by one of the present authors[4],and by Woon and Dunning[6]),core correlation is often included —for technical reasons or‘because it cannot hurt’—in calculations using basis sets(e.g. the standard Dunning correlation consistent basis sets[16,17],which are of minimal basis set quality in the inner-shell orbitals)which are not adapted for nonvalence correlation.This can often cause errors on computed properties well in excess of the basis set incompleteness error:For instance,a comparison between valence-only[18]and all-electron[19]CCSD(T)/cc-pVTZ harmonic frequency calculations on the cyclic isomer of C4suggests core correlation contributions to the harmonic frequencies of up to50cm?1,a factor of?ve more than the true correction obtained[18]with a core correlation basis set.
For the elements B–Ne and Al–Ar,the gap between valence and inner-shell orbital energies is large enough that a conventional core-valence separation of the orbital energies is easily made.Things are less simple further down the periodic table.Bauschlicher[20,21]noted that for gallium and indium halides,the valence(2s)orbitals of the halogen are below the Ga(3d)or In(4d)‘core’orbitals in energy.At the very least,these d orbitals should be added to the correlation space;suitable basis sets for this purpose have been developed by Martin and Sundermann[22]for Ga and Ge,and by Bauschlicher[21]for In.
But similar issues arise with Group1and2elements.Radom and coworkers[23,24] recently noted catastrophic failures of G2theory and related methods in predicting the heats of formation of various alkali and alkaline earth metal oxides and hydroxides:for example,the binding energy of K2O is underestimated by no less than256kJ/mol!Upon correlating all electrons,this error decreases to60kJ/mol,which is further decreased to17
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kJ/mol when more sophisticated electron correlation methods are used.Inspection of an atomic orbital energy table[25]quickly reveals why:the oxygen2s and2p valence orbitals lie below the potassium3s and3p inner-shell orbitals,rendering the conventional separation between‘valence’and‘core’orbitals essentially meaningless.Inclusion of Group1and2 subvalence correlation—termed‘relaxed inner valence’(RIV)by Radom and coworkers[23]—may in fact be the appropriate treatment,not just for K(and Ca)compounds,but for alkali and alkaline earth metal compounds in general.(One of the?rst papers to recognize the importance of inner-shell correlation for alkali metals may have been that by Liu and coworkers.[26])
This problem is far from academic,considering the great importance of K+,Ca2+,Na+, and Mg2+complexes in molecular biology.In addition,a number of these interactions(e.g., of the cation-πtype)are not necessarily amenable to density functional treatments without validation of some kind by means of ab initio methods.Clearly,the availability of high-quality core-valence basis sets for the elements Li,Be,Na,Mg,K,and Ca would bene?t the high-accuracy computational thermochemistry and spectroscopy communities as well as biomolecular modelers.The purpose of the present work is the development and validation of CVnZ(core-valence n-tuple zeta,n=D,T,Q,5)basis sets for these elements.
https://www.doczj.com/doc/d28720733.html,PUTATIONAL DETAILS
All electronic structure calculations carried out in the present work were carried out using the MOLPRO2000.1and2002.3program systems[27,28]running on SGI Origin2000(12×MIPS R10000,300MHz and4×MIPS R10000,195MHz,IRIX6.5)and Compaq ES40 (4×EV67,667MHz,Tru64Unix4.0f)minisupercomputers,as well as Compaq XP1000 (EV6,500MHz,Tru64Unix4.0f)and dual Intel Xeon(1.7,2.0and2.4GHz,RedHat Linux 7.2and7.3)workstations.
Unless explicitly noted otherwise,energy calculations were carried out at the CCSD(T) level;for open-shell systems,single-determinant ROHF reference functions were used,but the de?nition of the CCSD(T)energy according to Watts et al.[29]was employed throughout.
Validation calculations on diatomic molecules were carried out as follows.Energies were computed at21equidistant points around the putative bond distance with interpoint spac-ings of0.01–0.03?A,depending on the curvature of the surface.Energies at these points
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were converged as precisely as feasible,with integral evaluation thresholds being tightened as necessary.Polynomials of increasing order were then?t through the points,and the signi?cance of the additional order terms subjected to a Fisher-Snedecor test.The expan-sion was truncated at the point where the two-way signi?cance of the next higher order dropped below99%.The retained expansion was generally of order between six and eight. The minimum of this curve was then sought by means of a Newton-Raphson method,and the curve re-expanded around the minimum.A Dunham analysis[30]was then carried out on the?nal curve.The computed dissociation energies at0K,D0,reported in the tables include anharmonic zero-point corrections from the computedωe andωe x e at the same level of theory.
As for the accompanying basis sets,standard cc-pV n Z basis sets were used throughout on H.For O and F,aug-cc-pV n Z basis sets[31]were used in valence calculations and aug-cc-pCV n Z basis sets[6]in calculation where the O and F(1s)cores were correlated.For S and Cl,the aug-cc-pV(n+d)Z basis sets of Wilson et al.[32]were used in valence calculations, and the cc-pCV n Z basis sets of Peterson[10]in calculations where the(2s,2p)cores of these elements were correlated.
Where deemed necessary,scalar relativistic e?ects were assessed by means of CCSD(T) calculations within the Douglas-Kroll-Hess approximation[33,34]as implemented in MOL-PRO2002.3[28].
III.OPTIMIZATION OF CV n Z BASIS SETS
A.General procedure
The basis set optimizations were carried out using a Fortran program developed in-house. Derivatives were obtained numerically using central di?erences,yielding both the gradient and the diagonal of the Hessian.The step thus obtained—essentially Newton-Raphson with neglect of o?-diagonal Hessian elements—was combined with a Brent line search.Our experience with this simple but fairly robust optimization algorithm is quite good as long as optimization parameters are not too strongly coupled.In the presence of signi?cant coupling, DIIS(Direct Inversion of the Iterative Subspace)[35]dramatically sped up convergence.
Finite di?erence step sizes were made roughly proportional to the parameters themselves,
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and increased as necessary if the parameter surface in the a?ected direction was found to be particularly‘?at’.
Some additional optimizations were carried out using an adaptation of the DOMIN program by P.Spellucci[36],which is an implementation of the BFGS(Broyden-Fletcher-Goldfarb-Shanno)variable-metric method.Numerical derivatives of order two,four,and six were used:the lower orders until an approximate minimum was reached,after which the optimization was re?ned using the higher orders.In most cases,however,the simple procedure outlined above appeared to be more robust.
For the purposes of the optimization(and since only very small systems are involved), integral evaluation,SCF and CI convergence thresholds in MOLPRO were tightened to essentially machine precision.Basis set parameters were converged to at least four signi?cant digits,and?ve where at all possible.
In cases where many primitives of a particular angular symmetry are required,we initially constrained these functions to follow an even-tempered sequenceζi=αβ(i?n?1)/2,where n is the total number of primitives.Only when optimumαandβhad been reached were the individual exponents optimized further without any constraints.If a set of(n?1)primitives of that symmetry was already available(in casu,from a previously optimized smaller basis set),the geometric mean of their exponents was taken as the starting value forα,and the arithmetic mean of the ratios between successive primitives as the initial value forβ.
A few‘checks and balances’can generally be applied to the?nal exponents:
1.within a row,the geometric mean of the exponents should increase roughly as(Z?)2,
where Z?is the‘shielded’nuclear charge(?rst Ahlrichs-Taylor rule[37]);
2.exponents in a larger set(e.g.3d)should mesh with the next smaller set(e.g.2d);
3.the ratio of successive exponents in a set should be about two or higher,and all gaps
within the core or valence parts should roughly be of the same order;
4.the geometric mean of the exponents for each angular momentum should roughly
increase by a factor of1.2for each step up in L(second Ahlrichs-Taylor rule[37]).
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B.Li and Be
For Li and Be,the‘uno?cial’cc-pV n Z basis sets of Feller[38]supplied in the MOLPRO 2000.1basis set library were taken as starting points.The quantity optimized for is the(1s) correlation energy at the CISD level for the Li(2S)and Be(1S)ground states,respectively. This happens to be equivalent to E[CISD,full]?E[SCF]for Li,but is equal to E[CISD,full]-E[CISD,valence]for Be.
There exists a tradition of optimizing basis sets for correlated calculations at the CISD level,since CISD is a variational method.However,optimizations for the CCSD or CCSD(T) counterparts of the abovementioned correlation energies yield very similar basis sets,which would have been of identical quality in molecular calculations.(A table of these exponents for the CVDZ,CVTZ,and CVQZ cases can be found in the Supplementary Material[39].) By analogy with the cc-pCV n Z basis sets for B–Ne[40],1s1p,2s2p1d,3s3p2d1f,and 4s4p3d2f1g sets of primitives were added to the cc-pVDZ,cc-pVTZ,cc-pVQZ,and cc-pV5Z basis sets,respectively.Successive angular momenta were optimized individually,after which the complete set of exponents was further optimized together.
Multiple local minima exist for the larger sets,and care was taken to ensure that the ?nal optimized basis set re?ects the most‘contiguous’(or most‘even-tempered’)solution in the sense of having no obvious‘gaps’between exponents.
Aside from this issue,the basis set optimizations proceeded uneventfully.
C.Na and Mg
Likewise,for Na and Mg,unpublished cc-pV n Z basis sets of Feller[38]were taken as the starting point.In this case,we optimized for the2s2p correlation energy,found as E[CISD,2s2p3s]-E[CISD,3s]for Mg and as simply E[CISD,2s2p3s]-E[SCF]for Na.Note that the1s orbitals are constrained to be doubly occupied throughout:not only will the e?ect of this’deep core’orbital on chemically signi?cant properties be negligible,but including it in the optimization would bias the exponents towards the large—but chemically quite invariant—core-core correlation energy rather than the chemically more signi?cant2s2p core-core and core-valence correlation energies.
Since the highest core correlation orbital is of p symmetry in this case,the basis sets
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are rather larger,involving addition of1s1p1d,2s2p2d1f,3s3p3d2f1g,4s4p4d3f2g1h core correlation sets to the cc-pVDZ,cc-pVTZ,cc-pVQZ,and cc-pV5Z sets,respectively.
For the CV5Z basis sets for Na and Mg,simply optimizing a set of core correlation s functions leads to such serious near-linear dependence problems that the basis would in practice be unusable.For want of an alternative,we simply uncontracted an additional four s primitives instead.
D.K and Ca
The core-valence gap in Ca,and particularly K,is so small that the optimization of regular cc-pV n Z basis sets would be of largely academic interest.Feller and coworkers previously published CVDZ,CVTZ,and CVQZ basis sets for K[41];the sp exponents for the CVDZ and CVTZ basis sets were taken from(15s,12p)and(18s,15p)basis sets,respectively,of Ahlrichs and coworkers[42],while those for the CVQZ basis set were taken from the Partridge-1 set[43],which is of(23s,19p)uncontracted size.
Initially we employed these basis sets unaltered,and merely added a CV5Z basis set. This was obtained as follows,starting from the Partridge-3basis set:
?the basis set was contracted to miminal(i.e.[4s3p])in an atomic calculation on the ground state
?the four outermost s and p primitives each were decontracted
?[4d3f2g1h]functions were optimized at the valence-only CISD level for the K2molecule at its experimental bond distance,yielding an intermediate cc-pV5Z basis set
?core correlation functions were obtained by optimizing the atomic E[CISD,3s3p4s]-E[SCF]energy.The optimization of the s and p functions was plagued by insur-mountable near-linear dependence problems,and we ended up merely decontracting an additional four primitives of s and p symmetries each.In addition,a crossover occurred between the highest d exponent of the underlying cc-pV5Z basis set and the lowest d exponent required for the inner-shell correlation,and it was decided to merely keep the outermost three d primitives constant while optimizing all?ve remaining d primitives for3s3p correlation.
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Thus,our original CV5Z basis set was obtained.However,as evidenced in Table I, basis set convergence of properties for K2and KH was less than satisfactory.In particular, inspection of the dissociation energy as a function of the basis set reveals that for K2,the CVTZ,CVQZ,and CV5Z results are nearly collinear,which is obviously undesirable.For this reason,the d,f,...exponents of the K CVTZ and CVQZ basis sets were reoptimized in the same manner as the CV5Z basis set.In the process we found the‘valence correlation’d and f exponents in the original Feller basis sets to be excessively‘tight’,and with the adjusted basis sets(denoted‘version0.1’in Table I),increases of6.5and7.0kJ/mol are seen in the CVTZ and CVQZ D0values.Other molecular constants are also a?ected quite signi?cantly.While the Feller CVTZ and CVQZ were not found to be as problematic for the other K compounds considered in this work,they are clearly unsuitable for K2or any other system with similar long-distance bonding.
Analogously,we optimized CV n Z(n=D,T,Q,5)basis sets for Ca,starting from Ahlrichs 14s9p,Partridge-120s12p,Partridge-223s16p,and Partridge-326s16p primitive sets.Ini-tial attempts to optimize basis sets for the3P atomic excited state(analogously to the sp-hybridized state of Be)yielded exceedingly poor basis set convergence of molecular prop-erties,and these basis sets were abandoned in favor of1S ground-state optimized basis sets. (We also attempted optimizations in the CaH2molecule,and found basis set parameters obtained there to be very similar to those for the1S atomic ground state.)Valence correla-tion functions were optimized for the valence correlation energy of the ground-state calcium atom,and core-valence functions for E[CISD,3s3p4s]-E[CISD,4s].For the CVQZ and CV5Z basis sets,the optimized‘valence’and‘subvalence’d and f shells interlock,and as a result only the outermost2d2f were held at their valence-optimized values and the remainder reoptimized for inner-shell correlation.No such issues arose with the g and h functions. Once again,basis set convergence of molecular properties(e.g.for CaH,but also for other diatomics,not displayed here)was found to be somewhat unsatisfactory.
For both atoms,we then optimized a sequence of four‘stretch-tuned’basis sets[44], i.e.basis sets in which the exponents of each angular momentum obey the following four-parameter relation:
lnζn=α+n(β+(n?1)(γ+(n?2)δ))(1) (A total of only eight parameters thus had to be optimized for each basis set.)The particular sequence of contraction sizes chosen was(20s12p),(22s14p),(24s16p),and(26s18p).The
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valence and inner-shell correlation functions were optimized as before.
These basis sets(denoted‘version0.2’in Table I)appeared to have better convergence properties.However,something was clearly still not satisfactory.For instance,basis set convergence for the ionization potentials of K and Ca atoms was found to be atypically slow (Table II).
It then occurred to us that,as the4s orbital of these atoms is very di?use,the atom-optimized p functions may be too‘tight’(as they were optimized for atoms with vacant 4p orbitals)to contain suitable?rst polarization/angular correlation functions for the outer part of the4s orbital.This assumption was veri?ed by optimizing single‘probe’basis functions of various symmetries on top of CV n Z basis sets held constant.(Only valence electrons were correlated,as otherwise the functions would have fallen into the‘gravity well’of the inner-shell electrons.)A very noticeable lowering of the total energy was seen upon adding a single p function,the optimum exponent of which indeed turned out to be ‘looser’than any of the existing p functions.An additional‘loose’p function led to a further improvement for the K CV n Z(n=D,T,Q)basis sets,but not for the K CV5Z basis set(the outer p primitive of which is already quite‘loose’)or any of the Ca basis sets.Consequently, the valence correlation parts of the CV n Z basis sets were reoptimized with two and one additional p functions added,respectively,for K and Ca,and afterwards the inner-shell part was reoptimized for consistency.Thus our?nal CV n Z basis sets were obtained.As seen in Table I,basis set convergence of molecular parameters is now satisfactory.For IP(K)and IP(Ca),nearly exact values are now obtained(Table II).
Since the primitive K and Ca basis sets may be somewhat bulky for some applications, we have also generated SDB-CV n Z basis sets,which are combinations of the valence and subvalence parts of the CV n Z basis sets with small-core Stuttgart-Dresden-Bonn[45]rel-ativistic e?ective core potentials.The latter replace the(1s2s2p)electrons.Unlike the situation with large-core basis set where reoptimization of the basis set is essential[22],we have kept all exponents at their all-electron values and merely‘pruned’and recontracted the basis set.Speci?cally,the atomic SCF calculation was repeated with the(1s2s2p)orbitals replaced by the SDB pseudopotential denoted‘ECP10MWB’.Then all primitives with ab-solute coe?cients of less than10?5in any valence orbitals were deleted,and the orbitals recontracted.
All basis sets obtained in this work are available in machine-readable form(Gaussian and
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MOLPRO formats)as supplementary material[39]to the present paper.Contracted basis set sizes and numbers of basis functions for each element are given in Table IV.
IV.V ALIDATION FOR DIATOMIC MOLECULES
A.Diatomic metal hydrides
Since hydrogen has no core electrons,there are no di?erential core-core contributions (just core-valence)to the molecular https://www.doczj.com/doc/d28720733.html,puted and experimental data for the diatomic hydrides are given in Table V.
As noted previously,the inner-shell contribution to the LiH spectroscopic constants is quite appreciable,as can be expected from the small Li(1s)-H(2s)gap of about2a.u.We note that the CCSD(T,riv)/CV5Z results reproduce the Born-Oppenheimer bond distance and harmonic frequency to within0.0002?A and0.2cm?1,respectively.Neglect of Li(1s)cor-relation leads to errors of0.012?A and13.5cm?1,respectively.Nevertheless,the contribution to D e does not exceed1.2kJ/mol.
The corresponding core-valence gap for BeH is almost doubled,which translates into sub-stantially reduced core-valence contributions(relatively speaking)to r e andωe.Interestingly, the contribution to D0reaches nearly2kJ/mol.
In contrast,the Na(2p)-H(1s)gap narrows to no more than1a.u.,and in NaH we see inner-shell correlation contributions of33cm?1toωe and0.035?A to r e.Interestingly,once more D e is nearly una?ected.Once more,the CCSD(T,riv)/CV5Z results are in excellent agreement with experiment for the spectroscopic constants:applying a W2-type extrapola-tion for D0results in a value of182.35kJ/mol,within0.3kJ/mol of experiment.
Given that the Mg(2p)-H(1s)gap is not dissimilar from the corresponding one in LiH, it is not greatly surprising that the importance of core-valence contributions is again much smaller than in NaH.However,the8kJ/mol contribution to D0is considerably more sig-ni?cant.
In KH,the K(3p)and H(1s)orbitals are closer than0.5a.u.,and the contributions of nearly0.1?A and44cm?1to r e andωe,respectively,clearly suggest that any sort of‘valence correlation only’calculation on a K compound should be viewed with great suspicion.Note that the core-valence contribution to D0is negative in this case,as was previously found
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(e.g.[12])for aluminum and silicon hydrides.
In comparison,the Ca(3p)–H(1s)gap widens to0.84a.u.,and core-valence e?ects on the molecular properties are mitigated accordingly.Like for MgH and KH,inner-shell correlation in fact slightly reduces the dissociation energy.
With the exception of KH and CaH,the di?erential core-valence contributions appear to have converged with respect to the basis set at the CVQZ stage.This in itself satis-?es a minimum requirement for treating the inner-shell correlation contribution separately, something which is de?nitely inappropriate for KH.
On the whole,agreement between CCSD(T,riv)/CV5Z and experiment can only be de-scribed as quite satisfactory.For systems other than LiH and NaH,imperfections in the CCSD(T)electron correlation method may account for most of the remaining discrepancy between computed and observed harmonic frequencies[46].
B.Metal diatomics
The alkaline earth metal dimers(particularly Be2)exhibit such severe multireference character that they warrant studies in themselves(which would,however,focus on electron correlation methods rather than basis sets,see e.g.[47]and references therein).Results for species other than Be2can be found in Table VI.
In Li2,subvalence correlation accounts for0.024?A,which is sizable by spectroscopist’s standards.In Na2,this is drastically increased to nearly0.1?A,and reaches a whopping 0.23?A in K2.Interestingly,these contributions are quite close to double their metal hydride counterparts.As expected,LiNa and NaK represent scenarios intermediate between the homonuclear diatomics of the constituent elements.Changes inωe are modest in absolute numbers,but for these molecules represent relative errors of up to5%.It is quite clear how-ever that,with the possible exception of Li2,inclusion of subvalence correlation is essential for reliable molecular parameters.Once again we see,however,that bond energies are only a?ected mildly:0.8kJ/mol in Li2,1.7kJ/mol in LiNa,1.6kJ/mol in Na2,and only0.5 kJ/mol in K2.
Once again,a basis set of CVQZ quality appears to be close to convergence for the di?erential core-valence e?ects.
E?ects for Mg2and Ca2are considerably milder than for their alkali neighbors,yet(3s,3p)
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correlation reduces the Ca2bond distance by0.07–0.08?A,not negligible by any reasonable standard.The discrepancies between theory and experiment for Mg2primarily re?ect the inadequacy of the CCSD(T)method for this highly multireference system.In contrast,Ca2 yields quite satisfying results compared to experiment.
Agreement between our best calculations and experiment can only be described as excel-lent for Li2.The same would be true of Na2if it were not for the bond length which is still 0.003?A too long at the CCSD(T,riv)/CV5Z level.However,at the DK-CCSD(T)/CVQZ level,we?nd a scalar relativistic correction to the bond length of-0.006?A.(If this correc-tion would seem to be exaggerated,we note that the Na2potential curve is quite?at,and that already for OH?and HF,scalar relativistic corrections were found to be required for spectroscopic-quality results[48].)In K2,our best calculated results are likewise in excellent agreement with the experimental spectroscopic data except for r e,which is calculated to be 0.014?A longer than the observed value.At the DK-CCSD(T)/CVQZ level,we?nd a rela-tivistic contribution of-0.013?A to the bond length,which explains most of the discrepancy. In addition,the(2s,2p)‘deep core’orbitals are energetically in the same range as the(1s) orbitals in C and N,so it cannot be entirely ruled out that‘deep core’correlation may a?ect molecular properties in K compounds.
We optimized a CCVTZ(deep core valence triple zeta)basis set for K.In these calcu-lations,the CVTZ basis set was held constant and exponents of2s2p2d1f basis functions optimized for E[CISD,2s2p3s3p4s]?E[CISD,3s3p4s],i.e.for deep-core correlation energy taken in isolation.As can be seen in Table III,these exponents are obviously much‘tighter’, by almost an order of magnitude,than those required for subvalence correlation.Hence,any ‘deep core’result in a mere valence and subvalence CV n Z(let alone a valence-only cc-pV n Z set)should be regarded with skepticism at best.
The only change of note we see in the molecular properties when using this CCVTZ basis set for K2is a shortening of the K–K bond by another0.0018?A.We also attempted to optimize a CCVQZ basis set but ran into insurmountable near-linear-dependence prob-lems;however,the CCVTZ result should at least give an indication of the(fairly modest) magnitude of this e?ect.
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C.Diatomic metal halides
This set of molecules is particularly revelant because of the deep-lying valence s orbitals on the halogen atoms.Relevant results are collected in Table VII.
Firstly,for LiF the contribution of Li(1s)correlation to the binding energy is somewhat more noticeable(4kJ/mol).Its inclusion also causes a contraction of the bond by0.015?A and an increase inωe of12cm?1.The further e?ect of permitting F(1s)correlation is nearly negligible in comparison.The Cl(2s,2p)correlation e?ect is somewhat more noticeable but still Li(1s)correlation accounts for the lion’s share of the changes.
The F(2s)and Na(2p)orbitals are nearly degenerate,and hence one would expect valence-only calculations on NaF to be problematic,to say the least.Nevertheless,while the e?ect of Na(2s,2p)correlation on the molecular constants is quite noticeable and its inclusion clearly essential for accurate calculations,the results obtained are not outright nonsensical.Of course,considering the di?erence in electronegativity between the elements,the combination of Na+and F?would yield a more appropriate(if perhaps extreme)‘atoms in molecules’picture—and the corresponding orbital energy gap in this admittedly extreme scenario is
0.72a.u.with the Partridge3basis set.The corresponding‘ionic’gap for NaCl amounts to
1.07a.u.,explaining why also for NaCl,valence-only results are not totally unreasonable.
The person carrying out calculations on KF and KCl has no such luck.The inclusion of K(3s3p)correlation shiftsωe in KF upwards by no less than20%,and the contribution to D e is seen to be on the order of170kJ/mol.In fact,the‘valence’results are better described as referring to correlating the z component of K(3p)and freezing the F(2s),which obviously makes no chemical sense at all.The valence-computed dissociation energy of KCl agrees deceptively well with experiment,but an error of0.3?A in the bond distance and of a factor of three in the anharmonicity constant should discourage any quantum chemist from performing valence-only calculations on this type of species.
While obviously signi?cant for spectroscopic purposes,the e?ects of metal subvalence correlation in MgF and MgCl are clearly less prominent than in NaF and NaCl,respectively, and with the beryllium halides,one clearly could‘get away’with a di?erential treatment. In contrast,in CaF a calcium subvalence contribution to D0of180kJ/mol is found,not to mention+46cm?1onωe and a factor of two onωe x e.Oddly,the e?ect on the bond length is comparatively small(0.04?A).The opposite scenario is seen for CaCl,with a?r e of0.1?A
14
but otherwise not outlandishly erroneous values for the other spectroscopic constants.CaF and CaCl results resemble more the potassium halides.
And once again,the CCSD(T,riv)/CV5Z results agree as well with experiment as can reasonably be expected.
We have also considered calculations in which subvalence correlation on the halide was permitted.However,for K and Ca compounds with{C,N,O,F},the(1s)orbital of these latter elements is in fact below the K(2s,2p)‘deep core’orbitals in energy,and therefore any such calculation will require the use of CCV n Z‘deep core’basis sets on the metal.Such calculations are su?ciently costly that one might want to limit them to single-point energy calculations in high-accuracy thermodynamic work.For MCl,the most noticeable e?ect of including(2s,2p)subvalence correlation on chlorine is a contraction of r e by0.003?A.
D.The metal chalcogenides
We will primarily focus on the oxides.Results can be found in Table VIII.
Clearly,changes of13cm?1and6kJ/mol,respectively,forωe and D e of BeO suggest the importance of metal(1s)correlation in this system;contributions from O(1s)correla-tion are an order of magnitude less important.Note that the experimental data can be reproduced almost exactly at the CCSD(T,all)/CV5Z level,despite BeO having pronounced multireference character and in fact being on the borderline of applicability of CCSD(T)(see e.g.[49]).In the isovalent BeS system,Be(1s)correlation is still noticeably more important than S(2s,2p)correlation,although the di?erence is not as pronounced as its counterpart in BeO.
Changes between valence-only and RIV treatment of0.017?A in r e(MgO)and23cm?1 inωe(MgO)speak for themselves.The MgO molecule has very pronounced multireference character,and accurate reproduction of the experimental spectroscopic constants would required an elaborate multireference treatment.Subvalence correlation e?ects in MgS are rather milder.
In contrast,inspection of the computed spectroscopic constants for CaO immediately reveals that valence-only calculations on this system are essentially exercises in wasting computer time.Valence-only bond distances and dissociation energies are o?by a quarter of an?A,and a factor of six in D0.Respectable agreement with experiment can however
15
be reached by correlating the Ca(3s,3p)electrons.Obviously,the large uncertainties in the measured dissociation energies preclude really?ne comparisons with experiment:on the basis of the preceding,it can perhaps be stated that the calculated binding energies are more reliable than the experimental ones for the alkali(ne earth)metal chalcogenides.
Once again,correlating the(1s)orbital on O would require including(2s,2p)deep-core correlation in Ca,otherwise meaningless results are obtained.
E.Additional d functions on Ca
Wesolowski et al.[50],in a study of calcium oxide,observed especially poor performance for a valence-only atomic natural orbital(ANO)basis set[51].This was considerably im-proved when high-exponent d functions were added.They noted that Ca+has a low-lying 2D state only1.7eV above the2S ground state,and showed that said ANO basis set over-estimates this separation by nearly a factor of three.Addition of several very high-exponent d functions,taken from the6-311G(2df)basis set for Ca[52](which treats the(3d)orbital on a valence footing),results in an at least semiquantitatively correct result.
As the present basis sets were developed from the ground up with inner-shell correlation in mind,they intrinsically contain high-exponent d functions and should therefore be much less susceptible to the problem.As shown in Table IX,quite good agreement with the experimental transition energy is obtained for CVQZ and CV5Z basis sets,but the smaller basis sets leave something to be desired.
We therefore proceeded to optimize CV(n+d)Z,CV(n+2d)Z,and CV(n+3d)Z basis sets in the following fashion.(Both the nomenclature and the procedure bear resemblance to the cc-pV(n+d)Z basis sets for second-row elements[32].)All angular momenta other than d were kept constant,as were the valence-optimized d functions(see above).The remaining d functions were reoptimized for inner-shell correlation with one,two,or three additional d functions added.(In the CV(Q+d)Z and CV(Q+2d)Z basis sets,it was found necessary to constrain the exponents to stretch-tuned and even-tempered sequences,respectively.) As can be seen in Table IX,the2D←2S excitation energy indeed converges considerably faster for the CV(n+d)Z and CV(n+2d)Z series than for the CV n Z series.After applying a scalar relativistic correction by means of the Douglas-Kroll method in an uncontracted CV(Q+d)Z basis sets,very good agreement with experiment can be achieved.As for the
16
molecular properties of CaO(Table VIII),the e?ect of additional d functions is quite dra-matic in the CVDZ case and still quite important in the CVTZ case,but tapers o?for CVQZ and becomes quite insigni?cant for CV5Z.We noticed similar behavior in the other CaX systems considered in this paper(Tables V,VI,and VII).Convergence as a function of the number of additional d functions appears to be approached for CV(D+3d)Z,CV(T+2d)Z, CV(Q+d)Z,and CV5Z(note particularly Table VIII).Basis set convergence of molecular properties along this sequence is clearly much smoother than for the unmodi?ed CV n Z basis sets.This is particularly true for CaO and,to a somewhat lesser extent,for CaF,least so for CaH and Ca2where basis set convergence was adequate to begin with.
V.CONCLUSIONS
Core-valence basis sets have been developed for the alkali and alkaline earth metals Li, Be,Na,Mg,K,and Ca.Validation calculations for a number of diatomics involving these systems reveal basis set convergence to be satisfactory.
The addition of low-exponent p functions to the K and Ca basis set is found to be essential for smooth basis set convergence of molecular properties.These functions accommodate angular correlation from the outer part of the4s orbital.
Valence-only calculations on K and Ca chalcogenides and halides yield large errors at best, and chemically nonsensical results at worst.In general,inclusion of subvalence correlation in K and Ca compounds is absolutely essential for even reliable(let alone accurate)results, while for accurate calculations,subvalence correlation in Na(and,to a lesser extent,Li and Mg)should be included,preferably as a‘baseline’treatment rather than an additive correction.The latter appears to be su?cient for Be compounds.Any study that seeks to address the importance of?rst-row element core correlation in K and Ca compounds should also consider deep-core(2s,2p)correlation from these latter elements.
For compounds involving Ca bound to highly electronegative elements,we strongly rec-ommend basis sets with additional d functions on Ca:our suggested sequence for basis set convergence studies would be CV(D+3d)Z,CV(T+2d)Z,CV(Q+d)Z,CV5Z.
17
Acknowledgments
JM is a member of the Lise Meitner Center for Computational Quantum Chemistry (Israel-Germany)and the Helen and Martin Kimmel Center for Molecular Design(Weizmann Institute).This research was supported by the Tashtiyot program of the Ministry of Science and Technology(Israel)and by the Minerva Foundation,Munich,Germany.MAI and MO acknowledge Ph.D.and M.Sc.Fellowships,respectively,from the Feinberg Graduate School (Weizmann Institute of Science).We thank a referee for bringing Ref.[50]to our attention.
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学外语 学习外语是我一生中最艰苦也是最有意义的经历之一。虽然时常遭遇挫折，但却非常有价值。 我学外语的经历始于初中的第一堂英语课。老师很慈祥耐心，时常表扬学生。由于这种积极的教学方法，我踊跃回答各种问题，从不怕答错。两年中，我的成绩一直名列前茅。 到了高中后，我渴望继续学习英语。然而，高中时的经历与以前大不相同。以前，老师对所有的学生都很耐心，而新老师则总是惩罚答错的学生。每当有谁回答错了，她就会用长教鞭指着我们，上下挥舞大喊：“错！错！错！”没有多久，我便不再渴望回答问题了。我不仅失去了回答问题的乐趣，而且根本就不想再用英语说半个字。 好在这种情况没持续多久。到了大学，我了解到所有学生必须上英语课。与高中老师不同，大学英语老师非常耐心和蔼，而且从来不带教鞭！不过情况却远不尽如人意。由于班大，每堂课能轮到我回答的问题寥寥无几。上了几周课后，我还发现许多同学的英语说得比我要好得多。我开始产生一种畏惧感。虽然原因与高中时不同，但我却又一次不敢开口了。看来我的英语水平要永远停步不前了。 直到几年后我有机会参加远程英语课程，情况才有所改善。这种课程的媒介是一台电脑、一条电话线和一个调制解调器。我很快配齐了必要的设备并跟一个朋友学会了电脑操作技术，于是我每周用5到7天在网上的虚拟课堂里学习英语。 网上学习并不比普通的课堂学习容易。它需要花许多的时间，需要学习者专心自律，以跟上课程进度。我尽力达到课程的最低要求，并按时完成作业。 我随时随地都在学习。不管去哪里，我都随身携带一本袖珍字典和笔记本，笔记本上记着我遇到的生词。我学习中出过许多错，有时是令人尴尬的错误。有时我会因挫折而哭泣，有时甚至想放弃。但我从未因别的同学英语说得比我快而感到畏惧，因为在电脑屏幕上作出回答之前，我可以根据自己的需要花时间去琢磨自己的想法。突然有一天我发现自己什么都懂了，更重要的是，我说起英语来灵活自如。尽管我还是常常出错，还有很多东西要学，但我已尝到了刻苦学习的甜头。 学习外语对我来说是非常艰辛的经历，但它又无比珍贵。它不仅使我懂得了艰苦努力的意义，而且让我了解了不同的文化，让我以一种全新的思维去看待事物。学习一门外语最令人兴奋的收获是我能与更多的人交流。与人交谈是我最喜欢的一项活动，新的语言使我能与陌生人交往，参与他们的谈话，并建立新的难以忘怀的友谊。由于我已能说英语，别人讲英语时我不再茫然不解了。我能够参与其中，并结交朋友。我能与人交流，并能够弥合我所说的语言和所处的文化与他们的语言和文化之间的鸿沟。
煤层气地球物理测井技术的思考 发表时间：2018-08-06T10:35:55.557Z 来源：《科技中国》2018年3期作者：唐万亨 [导读] 摘要：近一二十年来，随着大气污染，环保形势越来越严峻，煤层气作为一种热值高，燃烧后清洁，被重新审视，成为国际国内崛起的洁净、优质能源和化工原料。作为传统的煤田地质勘探行业，对煤层气这一新型的非常规能源的开采利用须要引起足够的重视。煤层气可以作为能源利用的开采方法，现在主要参照天然气开采模式，即采用地面钻井抽采。作为非传统能源，煤层气的勘探开采工艺肯定区别于传统煤田的工艺，这对勘探开采中起重要作用的 摘要：近一二十年来，随着大气污染，环保形势越来越严峻，煤层气作为一种热值高，燃烧后清洁，被重新审视，成为国际国内崛起的洁净、优质能源和化工原料。作为传统的煤田地质勘探行业，对煤层气这一新型的非常规能源的开采利用须要引起足够的重视。煤层气可以作为能源利用的开采方法，现在主要参照天然气开采模式，即采用地面钻井抽采。作为非传统能源，煤层气的勘探开采工艺肯定区别于传统煤田的工艺，这对勘探开采中起重要作用的测井工作也提出了新的要求。煤层气作为煤田伴生的一种非传统能源，因其的环保性，越来越受到广泛重视，本文就煤层气勘探开采过程中需要用到的测井技术浅谈下想法。 关键词：煤层气；测井技术；勘探开采 煤层气，指储存在煤层中以甲烷为主要成分、以吸附在煤基质颗粒表面为主、部分游离于煤孔隙中或溶解于煤层水中的烃类气体，俗称“瓦斯”，瓦斯是古代植物在堆积成煤的初期，纤维素和有机质经厌氧菌的作用分解而成。在高温、高压的环境中，在成煤的同时，由于物理和化学作用，继续生成瓦斯。瓦斯是无色、无味的气体，但有时可以闻到类似苹果的香味，这是由于芳香族的碳氢气体同瓦斯同时涌出的缘故。瓦斯对空气的相对密度是0.554，在标准状态下瓦斯的密度为0.716kg/m3，瓦斯的渗透能力是空气的1.6倍，难溶于水，不助燃也不能维持呼吸，达到一定浓度时，能使人因缺氧而窒息，并能发生燃烧或爆炸。瓦斯在煤体或围岩中是以游离状态和吸着状态存在的。瓦斯是煤的伴生矿产资源，属非常规天然气，其主要成分是烷烃，其中甲烷占绝大多数，另有少量的乙烷、丙烷和丁烷，此外一般还含有硫化氢、二氧化碳、氮和水气，以及微量的惰性气体，如氦和氩等。在标准状况下，甲烷至丁烷以气体状态存在，戊烷以上为液体。如遇明火，即可燃烧，发生“瓦斯”爆炸，直接威胁着矿工的生命安全。因此，矿井工作对“瓦斯”十分重视，除去采取一些必要的安全措施外，有的矿工会提着一个装有金丝雀的鸟笼下到矿井，把鸟笼挂在工作区内。原来，金丝雀对“瓦斯”或其他毒气特别敏感，只要有非常淡薄的“瓦斯”产生，对人体还远不能有致命作用时，金丝雀就已经失去知觉而昏倒。矿工们察觉到这种情景后，可立即撤出矿井，避免伤亡事故的发生。瓦斯爆炸一直是煤矿安全生产的一个重大隐患。近一二十年来，随着大气污染，环保形势越来越严峻，煤层气作为一种热值高，燃烧后清洁，被重新审视，成为国际国内崛起的洁净、优质能源和化工原料。 作为传统的煤田地质勘探行业，对煤层气这一新型的非常规能源的开采利用须要引起足够的重视。煤层气可以作为能源利用的开采方法，现在主要参照天然气开采模式，即采用地面钻井抽采。作为非传统能源，煤层气的勘探开采工艺肯定区别于传统煤田的工艺，这对勘探开采中起重要作用的测井工作也提出了新的要求。下面就煤层气的勘探开采对于测井工作所需要解决的的技术需求，浅谈下想法。 一、勘探过程中的测井 众所周知，气体能够长期保存在地下，有其必要的条件，因而应该从其赋存条件选择合适的测井方法。煤层气作为一种气体，评价其储量，必须有含气量、饱和度、孔隙度、渗透率（绝对渗透率和相对渗透率）、储层压力等。常规的煤田地质测井参数双侧向（DLL）、自然伽玛（GR）、自然电位（SP）、补偿密度（DEN）、补偿声波（AC）、井温（TEMP）、顶角（DEV）、方位角（AZIM）、双井径（CAL）等曲线。这些曲线显然不能满足对煤层气的评价，应引入新的测井参数，对煤层及所赋存的煤层气进行综合评价。补偿中子（CNL）测井，是在贴井壁的滑板上安装同位素中子源和远、近两个热中子探测器，用远、近探测器计数率比值来测量地层含氢指数的一种测井方法。目前广泛使用补偿中子来进行孔隙度测井。利用孔隙度和其它参数结合可以推算出渗透率、饱和度等相关评价参数。这些参数可以有效的对煤层气钻孔中煤层气的储量进行评价。 二、完井开采过程中的测井 固井阶段 煤层气开采井在裸眼井完工后，为了保证抽取生产，需要进行固井完井工艺。在此过程中，需要对固井完井质量进行检查，需要引入水泥胶结测井（CBL）和声波变密度测井（VDL）。两种方法的原理是通过声波幅度进行测井。水泥胶结测井（CBL）可以判断固井水泥环和套管的胶结程度，再引入声波变密度测井（VDL）可以评价水泥环和地层、套管的胶结程度。这些基本上可以解决固井质量评价。基于这两种原理的基础上，最新发展起来了水泥评价测井（CET）和脉冲回声测井（PET）,可以更好的不受外界微小环境及自身所处环境状态的影响，更好的完成水泥胶结评价。 射孔阶段 射孔是采用特殊聚能器材进入井眼预定层位进行爆炸开孔让井下地层内流体进入孔眼的作业活动。煤层气裸眼井固井完成后，需要进行目的层射孔。参考中国石油天然气集团对旗下的五大钻探工程公司（大庆、川庆、西部、渤海、长城）的测井分公司及中国石油天然气集团测井公司的分工，射孔属于测井公司业务的一部分。目前世界各国的射孔技术按输送方式可以分为两类：一是电缆输送射孔；二是油管输送射孔。按其穿孔作用原理可分为子弹射孔技术、聚能式射孔技术、水力喷射射孔技术、机械割缝式射孔技术、复合射孔技术等。煤层气抽采井在固井完成之后，要投入生产阶段，必须要进行目的层的射孔作业，因此射孔作业，也是煤层气测井需要关注的一个方面。 三、结语 煤层气测井是指根据煤层气储层(煤层) 与围岩在岩性物性上的差别，利用自然电位、双侧向（或感应）、微电极、补偿密度、自然伽马、声波时差、声波全波列、中子孔隙度以及井径测井等对其进行测井，煤层不仅是储存甲烷的储层，而且是生成甲烷的源岩。煤层的物理结构是一个双重孔隙，即煤层中有由基质孔隙和裂缝孔隙的孔隙系统，其裂缝孔隙又由主割理(面割理)和次级割理(端割理)组成。煤层甲烷呈三种状态存在于煤中，即以分子状态吸附在基质孔隙的内表面上；以游离气体状态存在于孔隙和裂缝；或溶于煤层的地层水中。由于煤层的物理结构以及煤层气(甲烷)的存储、运移等方面区别于常规天然气，因而传统的常规天然气储层的评价方法不适合于评价煤层气层。综上所述，煤层气测井对于我们传统煤田地质勘探系统的测井工作，面临诸多的新技术、问题和挑战，但是也有我们自身的优势。我们对
井下物探管理办法
文档仅供参考 附件7： 矿井物探管理办法 为规范矿井物探工作，提高地质、水文地质预测预报准确率，全面落实“物探先行，钻探跟进”的防治水要求，制定本办 法。 一、适用范围 各区域公司及矿井公司、各生产（基建）矿井。 二、地面物探管理 1、矿井地面物探工程立项、方法选择、观测系统确定必须参 考《汾西矿区地面物探总体规划》。 2、地面物探工程计划必须上报集团公司审查同意。 3、地面物探项目的招投标必须符合集团公司相关规定，参加 招标的单位必须具有乙级（含乙级）以上物探资质。 4、地面物探项目招标前必须编制工程设计并报集团公司组织 审查，未经集团公司审查不予审查报告。审查后确定的设计做为 招投标和施工的技术依据，设计变更必须经建设方、监理方同 意。 5、大中型物探项目（2km2及以上）必须聘请具有物探监理 资质的单位进行监理。小型物探项目，矿井必须参与项目开工、 试验、竣工验收全过程监督管理，并有详细的监管工作日志。 6、集团公司负责物探工程设计、报告的审查并批复。 7、地面物探项目设计、施工方法、质量管理、报告编制等必 须符合国家相关规程、规范要求。
三、井下物探管理 1、各矿井必须成立3人以上（包括3人）的物探技术小组，指定专职的物探技术人员，确保物探工作正常开展。同时按照集团公司要求派出物探技术人员学习培训，并按周积极开展内部自主培训，不断提高矿井的物探技术水平。 2、各矿井必须配备超前探测水情和构造的物探仪器，以及探测回采工作面地质异常的无线电波透视仪。 3、区域公司可根据实际情况以公司组建物探队伍，保证所属矿井物探工作正常开展。 4、各区域公司、矿井应制定物探仪器保管、维护、使用和交接管理制度，定期对物探仪器进行维护，仪器每两年须送到厂家对技术指标检校或大修。 5、所有开拓、掘进工作面必须使用电法仪器循环探测，要求探测全覆盖。物探范围内如过空巷，应重新探测。 6、为实现物探与钻探相匹配，使用大功率瞬变电磁仪，相邻两次探测间距不大于100米；使用小功率瞬变电磁仪的矿井，相邻两次探测间距不大于75米。 对可能存在地质构造的区段应使用地震类物探仪器探测。 7、受小窑采空区积水及富水构造影响严重矿井（柳湾、水峪、高阳、正文、正旺、正帮、正佳、正珠等）的采掘工作面，应采用瞬变电磁法、直流电法、地质探测仪法多种手段综合验证探查小窑采空区范围及其赋水性。
新编大学英语（第二版）第一册阅读文参考译文 Unit One 以生命相赠 1 炸弹落在了这个小村庄里。在可怕的越南战争期间，谁也不知道这些炸弹要轰炸什么目标，而他们却落在了一所有传教士们办的小孤儿院内。 2 传教士和一两个孩子已经丧生，还有几个孩子受了伤，其中有一个小女孩，8岁左右，她的双腿被炸伤。 3 几小时后，医疗救援小组到了。救援小组由一名年轻的美国海军医生和一名同样年轻的海军护士组成。他们很快发现有个小女孩伤势严重。如果不立即采取行动，显然她就会因失血过多和休克而死亡。 4 他们明白必须给小女孩输血，但是他们的医药用品很有限，没有血浆，因此需要相配血型的血。快速的血型测定显示两名美国人的血型都不合适，而几个没有受伤的孤儿却有相配的血型。 5 这位医生会讲一点越南语，忽视会讲一点法语，但只有中学的法语水平。孩子们不会说英语，只会说一点法语。医生和护士用少得可怜的一点共同语言，结合大量的手势，努力向这些受惊吓的孩子们解释说，除非他们能输一些血给自己的小伙伴，否则她将必死无疑。接着问他们是否有人愿意献血来救小女孩。 6 对医生和护士的请求，孩子们（只是）瞪大眼睛，一声不吭。此时小病人生命垂危。然而，只有这些受惊吓的孩子中有人自愿献血，他们才能够得到血。过了好一会儿，一只小手慢慢地举了起来，然后垂了下去，一会儿又举了起来。 7 “噢，谢谢，”护士用法语说。“你叫什么名字？” 8 “兴，”小男孩回答道。 9 兴很快被抱到一张床上，手臂用酒精消毒后，针就扎了进去。在整个过程中，兴僵直地躺着，没有出声。 10 过了一会儿，他发出了一声长长的抽泣，但立即用那只可以活动的手捂住了自己的脸。 11 “兴，疼吗？”医生问。 12 兴默默地摇了摇头，但一会儿忍不住又抽泣起来，并又一次试图掩饰自己的哭声。医生又问是不是插在手臂上的针弄疼了他，兴又摇了摇头。
煤田地球物理测井中塌孔对煤层解释的影响分析 在煤田地质勘探的过程中常常会因为钻探技术和泥浆材料问题，导致钻孔井壁出现残缺，产生塌孔现象，给煤层解释准确性造成一定的影响。为了能够更好的分析这个问题，文章对地球物理测井技术进行了相应的阐述，以及塌孔对煤田测井各参数曲线造成的影响，并采取相应的措施来解决问题。 标签：煤田地球物理测井；塌孔；煤层解释 Abstract：In the process of coalfield geological exploration，drilling technology and mud material problems often lead to drilling hole wall incomplete，resulting in hole collapse phenomenon，which has a certain impact on the accuracy of coal seam interpretation. In order to better analyze this problem，this paper expounds the geophysical logging technology，and the impact of borehole collapse on the parameters of coal logging curve，and takes the corresponding measures to solve the problem. Keywords：coalfield geophysical logging；caving hole；coal seam interpretation 众所周知，随着我国经济飞速的发展，对能源的消耗也随着快速的增加，尤其是传统能源之一的煤炭。煤田地质勘探和煤矿开采的技术也因此大发展，其中煤田地球物理测井技术备受关注，因为其便捷性的操作，广泛性的运用范围及精准的测量数据。 1 地球物理测井技术 1.1 地球物理测井技术的概述 地球物理测井技术是煤矿地质勘查和探索中一种不可或缺的勘探的方法。其是使用地下岩层的各种特性——导电性、放射性、电化学特性和声学特性等来测量地球相关的物理参数，显示地下岩层的构成情况的地质勘察的方法。煤田测井技术通过使用各式各样的测井机器能够在地面以下很深的地方进行实地探查，地球物理测井技术是采用先进的电子及传感器、计算机信息论、层析成像和数据处理等技术，借助专门的探测仪器设备，沿钻井剖面观测岩层的物理性质，以研究和解决地质问题，进而发现油气、煤、放射性、地下水等矿产资源。这样就突破了单一的地面勘探的不足，是测井技术最大的特点和优势所在，使得勘察和测试所得到的数据更具准确性和参考价值。 1.2 地球物理测井技术的分类 测井有三种基础的方式，分别是声、电、放射测井。而根据相关的物理特性测井又可以可划分成地层倾角测井、井温测井及声波测井等等。不管是哪一种测
地球物理探矿法 一、地球物理探矿法的基本原理 物探的基本特点是研究地球物理场或某些物理现象。如地磁场、地电场、放射性场等，而不是直接研究岩石或矿石，它与地质学方法有着本质上的不同。通过场的研究可以了解掩盖区的地质构造和产状。它的理论基础是物理学或地球物理学，系把物理学上的理论(地电学、地磁学等)应用于地质找矿。因此具有下列特点和工作前提： (一)物探的特点 1．必须实行两个转化才能完成找矿任务。先将地质问题转化成地球物理探矿的问题，才能使用物探方法去观测。在观测取得数据之后(所得异常)，只能推断具有某种或某些物理性质的地质体，然后通过综合研究，并根据地质体与物理现象间存在的特定关系，把物探的结果转化为地质的语言和图示，从而去推断矿产的埋藏情况与成矿有关的地质问题，最后通过探矿工程验证，肯定其地质效果。 2．物探异常具有多解性。产生物探异常的原因，往往是多种多样的。这是由于不同的地质体可以有相同的物理场，故造成物探异常推断的多解性。如磁铁矿、磁黄铁矿、超基性岩，都可以引起磁异常。所以工作中采用单一的物探方法，往往不易得到较肯定的地质结论。一般情况应合理地综合运用几种物探方法，并与地质研究紧密结合，才能得到较为肯定的结论。 3．每种物探方法都有要求严格的应用条件和使用范围。因为矿床地质、地球物理特征及自然地理条件因地而异，从而影响物探方法的有效性。 (二)物探工作的前提 在确定物探任务时，除地质研究的需要外，还必须具备物探工作前提，才能达
到预期的目的。物探工作的前提主要有下列几方面： 1．物性差异，即被调查研究的地质体与周围地质体之间，要有某种物理性质上的差异。 2．被调查的地质体要具有一定的规模和合适的深度，用现有的技术方法能发现它所 引起的异常。若规模很小、埋藏又深的矿体，则不能发现其异常；有时虽然地质体埋藏较深，但规模很大，也可能发现异常。故找矿效果应根据具体情况而定。 3．能区分异常，即从各种干扰因素的异常中，区分所调查的地质体的异常。如铬铁矿和纯橄榄岩都可引起重力异常，蛇纹石化等岩性变化也可引起异常，能否从干扰异常中找出矿异常，是方法应用的重要条件之一。 二、地球物理探矿法的应用及其地质效果 (一)应用物探找矿的有利条件与不利条件 1．物探找矿有利条件：地形平坦，因物理场是以水平面做基面，越平坦越好；矿体形态规则；具有相当的规模，矿物成分较稳定；干扰因素少；有较详细的地质资料。最好附近有勘探矿区或开采矿山，有已知的地质资料便于对比。 2．物探找矿的不利条件：物性差异不明显或物理性质不稳定的地质体；寻找的地质体或矿体过小过深，地质条件复杂；干扰因素多，不易区分矿与非矿异常等。 (二)物探方法的种类、应用条件及地质效果简要列于表4—5。 物探方法的选择，一般是依据工作区的下列三方面情况，结合各种物探方法的特点进行选择：一是地质特点，即矿体产出部位、矿石类型(是决定物探方法的依据)、矿体的形态和产状(是确定测网大小、测线方向、电极距离大小与排列方式等决定因素)；二是地球物理特性，即岩矿物性参数，利用物性统计参数分析地质构
大学英语精读1课文翻译 Unit1 Some Strategies or Learning English 学习英语绝非易事。它需要刻苦和长期努力。 虽然不经过持续的刻苦努力便不能期望精通英语，然而还是有各种有用的学习策略可以用来使这一任务变得容易一些。以下便是其中的几种。 1. 不要以完全同样的方式对待所有的生词。你可曾因为简直无法记住所学的所有生词而抱怨自己的记忆力太差？其实，责任并不在你的记忆力。如果你一下子把太多的生词塞进头脑，必定有一些生词会被挤出来。你需要做的是根据生词日常使用的频率以不同的方式对待它们。积极词汇需要经常练习，有用的词汇必须牢记，而在日常情况下不常出现的词只需见到时认识即可。你会发现把注意力集中于积极有用的词上是扩大词汇量最有效的途径。 2．密切注意地道的表达方式。你可曾纳闷过，为什么我们说 "我对英语感兴趣"是"I'm interested in English"，而说"我精于法语"则是"I'm good at French"？你可曾问过自己，为什么以英语为母语的人说"获悉消息或秘密"是"learn the news or secret"，而"获悉某人的成功或到来"却是"learn of someone's success or arrival"？这些都是惯用法的例子。在学习英语时，你不仅必须注意词义，还必须注意以英语为母语的人在日常生活中如何使用它。 3．每天听英语。经常听英语不仅会提高你的听力，而且有助你培养说的技能。除了专为课程准备的语言磁带外，你还可以听英语广播，看英语电视和英语电影。第一次听录好音的英语对话或语段，你也许不能听懂很多。先试着听懂大意，然后再反复地听。你会发现每次重复都会听懂更多的东西。 4．抓住机会说。的确，在学校里必须用英语进行交流的场合并不多，但你还是可以找到练习讲英语的机会。例如，跟你的同班同学进行交谈可能就是得到一些练习的一种轻松愉快的方式。还可以找校园里以英语为母语的人跟他们随意交谈。或许练习讲英语最容易的方式是高声朗读，因为这在任何时间，任何地方，不需要搭档就可以做到。例如，你可以看着图片或身边的物件，试着对它们详加描述。你还可以复述日常情景。在商店里购物或在餐馆里吃完饭付过账后，假装这一切都发生在一个讲英语的国家，试着用英语把它表演出来。
煤田地质勘探技术及特点分析 发表时间：2017-06-27T15:05:23.963Z 来源：《基层建设》2017年6期作者：李蒙召[导读] 摘要：煤田地质勘探技术，是在煤炭开发前利用多技术手段精确了解煤层厚度和深度的一种技术方式，可以说，它是设计开采方案、建立矿井和开采实施的基本依据。新疆煤田地质局一六一煤田地质勘探队新疆乌鲁木齐 830000 摘要：煤田地质勘探技术，是在煤炭开发前利用多技术手段精确了解煤层厚度和深度的一种技术方式，可以说，它是设计开采方案、建立矿井和开采实施的基本依据。在数字化和电子化飞速发展的新时期，我国煤炭开采工作在不断摸索和对实际新技术理念的广泛吸收之 后，形成了具有中国特色的煤田地质勘探学科的理论和勘探方法。随着新型科技技术的问世，我国煤田地质勘探技术发展将再上新台阶。本文就煤田地质勘探技术及特点进行了分析，以供参考。关键词：煤田地质；勘探技术；特点引言 我国地大物博，各种矿产资源丰富，煤炭的储藏量位居世界第三位!，但随着经济的发展和人民整体素质的提高，环保意识不断增强，对煤炭能源的需求也越来越高，需要一整套更加完善的技术来支撑，首当其冲的就是在煤炭开采前的勘探技术。虽然经过几十年的发展，我国煤炭的勘探技术不断发展，已近国际先进水平，但是已然跟不上时代发展的速度。为此，本文就目前煤炭勘探技术的特点进行分析总结，找到弱点，改善不足，同时探讨未来技术的发展方向，不断创新勘探技术，确保后续工作正常展开。 1 煤田地质勘探技术 1.1 地面地震勘查技术的应用在勘探实践中，高分辨二维地震、三维地震和多波多分量地震是最为常用的三种方法。应用该方法，需在采区设计前注意以下两方面问题：第一，搞清煤层赋存情况，底板的起伏形态，及断层法律规律，以此为依据圈定煤层分叉合并区。第二，客观评价对可能会给开采工作带来影响的含水层富水性，找准可采煤层的波及范围和各陷落柱的具体位置，根据评价结果制定相应的防水害预案。当地表条件适当时，实践工作中通常会选用三维高分辨率地震勘探技术进行勘探。 1.2 遥感技术的应用煤炭遥感技术是一种空间遥感新技术，由于这种技术具有实时性强!探测速度快!结果精准、整体性强等优势，因此，在探测、煤田地质和煤炭工业领域被广泛应用。随着计算机网络的飞速发展，煤炭遥感科学体系逐步完善，在煤田自燃环境监测，煤矿区环境监测，煤矿区水资源调查，煤炭资源调查，中小比例尺填图和区域地质研究的应用中成果显著，近年来它开始和物探!钻探仪器一起，被并称为煤田资源勘探的三大利器，随着煤田遥感技术与GIS及GPS等的深入结合应用，相继出现了中国煤田地质和煤炭资源调查信息系统。中国北方煤田自燃环境监测信息系统!中国煤矿区环境监测信息系统，煤矿区水资源调查信息系统!煤炭生产控制与土地复垦监测信息系统，一方面提升了各信息系统的智能化和半自动化水平，提高了探测的精准度和实时性。另一方面也实现了各信息系统的网络化、可视化和社会化，这一进步将为煤炭工业的可持续发展奠定坚实的基础。 1.3 测井勘查技术的应用主要是通过物理手段得到相关的物理参数对矿井进行实地勘察的一项技术，能够准确取得煤层的厚度和深度，也可以对没有煤层的地质进行勘察，根据地质特点进行分析，免做无用功。在地质调查过程中，地球物理测井技术主要是用来测量在矿区建设了矿区的地表温度，在施工开始前对表面温度区调查首次启动参数，在每个区域的表面温度分布和煤矿煤田详查温度值在工程勘察煤田的重要环节。用测井方法研究和检测的水文地质，从测井曲线，此方法可对一般分布和水的价值层面看，有一个大致的了解，所以在水文地质工作在修建性详细规划开始，其次在水文地质工作可以直接把水文测井方法。可以看出，与传统的抽油作业相比，测井对地质勘探工作的重要性更为精确、操作更方便、开采成本更低。虽然每个钻孔的测井资料反映了该井的地质剖面，但各井的数据之间必然存在一定的内在联系。钻井测井数据之间的关系的研究和分析，发现煤岩的曲线相互区别的特殊标志所示的形态特征、综合测井曲线对比的一些地区，为了解决矿、断层、煤层、岩层和地质问题的变化规律。 2 煤田地质勘探技术的主要特点 2.1 针对性、局部性针对性和局部性是地质勘探工作的主要特点。多年来，随着相关技术的不断进步和改善，方法越来越优良!有些甚至只需要对局部定点勘测就可以分析出煤层的分布状况!而针对性则具体表现在，对一些煤层分布较多的重点区域的环境情况进行重点勘探，以确保施工的安全问题和开采的工作效率。 2.2 资料丰富，手段多样我国煤矿分布的地理特点多种多样，环境也不尽相同，要针对不同的地区采取相应的方法，就要求相关科技工作人员要有不同的解决方案，综合素质要高。历经多年的努力，勘探技术不断完善，已经形成了体系!对不同的情况可以采取科学的方法，对症下药。我国勘探的相关数据资料也越来越丰富，方案的设计过程中，工作人员可以通过对相似的工程情况进行比较分析，提出高效率，少预算和安全稳定的施工方法。 2.3 继承性、补充性由于我国煤炭资源的开采率不断上升，相关技术也日趋完善，一些难开发的地段也可以进行安全的施工，但是，对于一些没有办法进行高效开采的地段我们还会采取稳健的方法，先开发好的地段，减少不必要的浪费，等日后技术更加成熟时再做打算。结束语 总而言之，在实际工程中，需要根据不同的条件，采取不同的勘探方式，将各项共有有机结合起来，严格的进行工程顺序，全面的研究地质信息，提交评估报告，科学的开采!这才是一整套完整的工作流程。只有这样，才能不断完善相关方面的技术工作，保障人们生命财产安全，提高企业的经济效益。参考文献：
环境地球物理勘查技术与方法探究 在工业化进程中，经济的发展伴随着地球环境的恶化，成为各个技术领域面临的问题。环境问题的解决一方面靠积极的预防，更要对已经产生的环境污染及危害进行治理，而作为一种环境监测方法，地球物理勘查技术的应用为环境监测与治理提供了技术支持。本文就环境地球物理勘查技术与方法进行探讨，希望会对我国的环境建设起到一定作用。 标签：环境保护地球物理勘查 0前言 科技的不断发展带来各项技术水平的不断提高，在环境治理方面也具备了一定的技术支撑。环境地球物理方法充分的发挥着环境科学与物理技术的两项优势，无论是进行大区域的环境物理变化，还是区域性的环境污染都具备了实用性及实效性的优势，为我国的环境监测以及保护提供科学的技术参考。 1对地下水污染的勘查技术 工业的发展与人类各种生活垃圾的出现，直接影响到了地下水源的质量，地下水污染问题也受到各个学术界的关注。地下水的主要污染源还是工业企业的污水排放以及工业垃圾没有进行进一步处理，其中还包括城市生活中所产生的大量垃圾，对垃圾的填埋直接影响了地下水质。地下水的质量直接与我们的生活用水息息相关，如果地下水一直受到污染，会使我们的生活水平直线下降，所以，对地下水污染的治理与预防是各个领域都在研究的问题。而在对地下水污染进行防治的过程中，首先要了解地下污染源的所在地点、污染的严重程度、地下水的流向以及污染源的分布等因素，才能在治理当中制定相应的方案。 1.1对垃圾填埋场的渗漏检测 大型的垃圾填埋场会对本地区的土质以及水质产生一定的影响，垃圾渗滤液在渗入地下后会使地层中介质的物理性能发生改变。通过对地球物理仪器设备的应用，可以检测出垃圾渗滤液导致的介质变化，进而分析出渗漏的范围以及地下水的污染程度，这种方法方便快捷，不需要进行大量的采样和打钻。 而针对不同的垃圾填埋状况以及工作目的，应该选用不同的工作方法。常用的方法有雷达法、电磁法、放射性法等，可以用来进行污染治理的前后对比当中。而对小范围内的垃圾填埋产生的影响做检测的话，可以采用激发极化法、探地雷达法等。在进行不同物理检测方法选择时，应该根据实地需要选择可行性的对策，具体为使污染体育背景之间具有明显的物性差别，也就是根据仪器的检测数据能够明显的得到相应的结论，使检测结果更科学。 1.2对地下运输管道的检测
M D 模型空间数据空间地球物理探测空间变换示意图 球物理探测方法简介及应用范围 地球物理学是用物理学的原理和方法，对地球的各种物理场分布及其变化进行观测，探索地球本体及近地空间的介质结构、物质组成、形成和演化，研究与其相关的各种自然现象及其变化规律。在此基础上为探测地球内部结构与构造、寻找能源、资源和环境监测提供理论、方法和技术，为灾害预报提供重要依据。 地球物理学的研究内容总体上可分为应用地球物理和理论地球物理两大类。应用地球物理(又称勘探地球物理)主要包括能源勘探、金属与非金属勘探、环境与项目探测等。勘探地球物理学利用地球物理学发展起来的方法进行找矿、找油、项目和环境监测以及构造研究等，方法手段包括地震勘探、电法勘探、重力勘探、磁法勘探、地球物理测井和放射性勘探等，通过先进的地球物理测量仪器，测量来自地下的地球物理场信息，对测得的信息进行分析、处理、反演、解释，进而推测地下的结构构造和矿产分布。勘探地球物理学是石油、金属与非金属矿床、地下水资源及大型项目基址等的勘察及探测的主要学科。 从数学角度讲，地球物理勘 探的过程可以抽象成从模型空 间通过某种映射关系，映射成可 以感知的数据空间，再通过逆映 射变换到模型空间，其映射关系 见右图。这种映射关系遵循地球 物理学的两大模型原理：滤波器 模型原理和场效应模型原理。因 此地球物理数据处理：一是基于 信号分析理论的信号处理技术， 主要目的是去杂、增益、提取有效信号；二是基于物理场效应理论的反演技术。 地球物理反演，就是在模型空间寻找一组参数向量，这组向量通过某种映射关系，能再现数据空间的观测数据，因此在一定的假设条件下，反演问题可以表示为某种误差泛函的极小化问题 min ‖G cal (M)-D obs ‖2 也就是地球物理反演是利用模型参数和模型正演来获取合成数据，再通过合成数据与观测数据的匹配估算出最佳M 参数。由此可见，地球物理反演实质上是正
????????????????? ????????????????????????????????????????????????????????????????????????????????????????????梯度法电位法充电法激电测深法各类剖面法激发极化法多级测深法偶极测深三级测深法对称四级测深法电测深偶极剖面法复合对称四级剖面法对称四级剖面法联合剖面法电剖面电阻率法充电法电位法天然场法直流电法法）无线电波透视法（阴影变频法（交流激电法）甚低频法（长波法）电磁法低频点测法 天然场法交流电法电法勘探???????????声波法横波法纵波法面波法反射波法 折射波法地震勘探 测量均匀大地的电阻率，原则上可以采用任意形式的电极排列来进行，即在地表任意两点(A 、B)供电，然后在任意两点(M 、N)测量其间的电位差，根据 （5.2.10)式便可求出M 、N 两点的电位. AB 在MN 间产生的电位差由上式解出大地电阻率,大地电阻率的 计算公式为 上式即为在均匀大地的地表采用任意电极装置(或电极排列)测量电阻率的基本公式。 其中K 为电极装置系数。 电法勘探的基本概念 电法勘探是以研究地壳中各种岩石、矿石电学性质之间的差异为基础，利用电场或电磁场（天然或人工）空间和时间分布规律来解决地质构造或寻找有用矿产的)11(2BM AM I U M -=πρ)11(2BN AN I U N -=πρ)1111(2BN BM AN AM I U MN +--=?πρI U K MN ?=ρBN BM AN AM K 11112+--=π
一类地球物理勘探方法，通称为电法。 场源 稳定电流场：点电源电场、两异极性点电源电场、偶极子源电场。 变化电流场：电磁场 装置类型：对称四极、三极、偶极 视电阻率均匀介质电阻率计算公式 实际上大地介质常不满足均匀介质条件，地形往往起伏不平，地下介质也不均匀，各种岩石相互重叠，断层裂隙纵横交错，或者有矿体充填其中，这时由上式得到的电阻率值在一般情况下既不是围岩电阻率，也不是矿体电阻率，我们称之为视电阻率。用ρs 表示 视电阻率与真电阻率在概念上有本质的不同，决定视电阻率值大小的因素有： 1） 不均匀体的电阻率及围岩电阻率； 2） 不均匀地质体的分布状态（形状大小、深浅及产状等）； 3） 供电电极和测量电极间的相互位置； 4） 工作装置和地质体的相对位置 电测深 电测深法是根据岩石和矿石导电性的差异，在地面上不断改变供电电极和测置电极的位置，观测和研究所供直流电场在地下介质中的分布，了解测点电阻率I U K MN ?= ρ
Unit 3 近年来，随着互联网技术的迅猛发展，互联网经济已成为一个热门话题。以蓬勃发展的电子商务为代表的互联网经济已成为经济发展的重要引擎。我国政府高度重视发展互联网经济，提出了“互联网+”的概念，以推动互联网与医疗、交通、教育、金融、公共服务等领域的结合。这将为互联网经济的发展提供极大的发展潜力和更广阔的发展空间。随着“互联网+”战略的深入实施，互联网必将与更多传统行业进一步融合，助力打造“中国经济升级版”。 In recent years, with the rapid development of Internet technology, the Internet economy has become a hot issue. As represented by the promising E-commerce, the Internet economy has become a strong driving force for the economic development. Our government attaches great importance to developing the I nternet economy and proposes the concept of “Internet Plus”, aiming to integrate the Internet with other industries, such as health care, transportation, education, finance, and public service. This will create great potential and broad prospects for the development of the Internet economy. With the implementation of the “Internet Plus” strategy, the Internet is certain to be integrated with more traditional industries and help build “the upgraded version of the Chinese economy”.
地球物理勘探知识点 一、名词解释 1.动校正：校正因炮检距不等而存在的正常时差的影响。 2.时距曲线：若测线是沿一条线进行的，则测线上各观测点坐标与波至时间的关系图称为时距曲线。 3.多次覆盖：指采用一定的观测系统获得对地下每个反射点多次重复观测的采集地震波讯号的方法。 4.电阻率剖面法：当保持供电电极距AB不动时，电极系探测深度一定，移动电极系时就可以反应一定深度范围内的地下电阻率的变化情况，这种方法称之为电阻率剖面法。 5.电法勘探：是以岩石、矿石的导电性、电化学活动性、介电性和导磁性的差异为物质基础，使用专用的仪器设备观测和研究地壳周围物理场的变化和分布规律，进而达到解决地质问题的目的的一组地球物理勘查方法。 6.转换波：与入射波波形不同的反射波和透射波。 7.高密度电法：是集电测深和剖面法于一体的一种多装置，多极距的组合方法。 8.槽波地震勘探：是在井下煤层开采工作面内进行的，地震测线接受点和激发点沿煤巷布设，直接探测煤层内地质构造或其他地质异常体的勘探方法。 9.温纳四极装置：一种三电位电极装置，一次组合，可以获得三种电极排列的测量参数。 10.横波：质点振动方向与传播方向垂直。 11.地电断面：根据地下地质体电阻率的差异而划分界限的断面。 12.视电阻率：在电场有效作用范围内各种地质体电阻率综合反映。 13.正常时差：各观测点有不同的炮检距，因而有不同的旅行时，他们相对于自激自收时的差称为正常时差。 14.静校正：设法消除地表因素影响的校正过程。 15.观测系统：测线上激发点和接收点的相对位置关系。 16.同类波：与入射波波形相同的反射波和透射波。 17.纵波：质点振动方向与传播方向一致。 18.电测深：电测深法是根据岩石和矿石导电性的差异，在地面上不断改变供电电极和测量电极的位置，观测和研究所供直流电场在地下介质中的分布，了解测点电阻率沿深度的变化，达到测深、找矿和解决其他地质问题的目的。 19.瞬变电磁法：是利用不接地回线或电极向地下发送脉冲式一次电磁场，用线圈或接地电极观测由该脉冲电磁场感应的地下涡流产生的二次电磁场的空间和时间分布，从而来解决有关地质问题的时间域电磁法。 20.水平叠加：又称为共反射点叠加或共中心点叠加，就是把不同激发点、不同接收点上接收到的来自于同一反射点的地震记录进行叠加。 二、填空题 1.地震勘探的三个主要步骤是采集、处理、解释 2.地震勘探的横波有SV波、SH波 3.联合剖面法曲线中的正交点和反交点分别反映低阻和高阻特征 4.常用电阻率法测量方法有：电阻率测深法、电阻率剖面法、高密度电阻率法 5.观测系统图示方法有视距平面法、普通平面法、综合平面法 6.从实用性出发，地震波可分为有效波和干扰波
物探方法简介 一、瞬变电磁法简介 1、瞬变电磁法技术原理 瞬变电磁法（Transient ElectromagneticsMethod, TEM）是以地壳中岩（矿）石的导电性与导磁性差异为主要物质基础，根据电磁感应原理，利用不接地回线或接地线源向地下发送一次脉冲磁场，在一次脉冲磁场的间隙期间，利用线圈或接地电极观测二次涡流场，并研究该场的空间与时间分布规律, 来寻找地下矿产资源或解决其它地质问题的一支时间域电磁法。下图即为瞬变电磁法原理的图解。 2、瞬变电磁法应用领域 瞬变电磁法施工简便、低阻探测能力强、精度高、探测深度大（地面1000m、井下150m），井下、井上均可施工。具有许多传统直流电法不可比拟的优点，可应用于： ◆地下水探测。瞬变电磁法可用于找水、咸淡水区分、地下电性
分层、圈定地下充水溶洞； ◆寻找金属矿床； ◆煤层顶底板富水性探测、巷道迎头超前探、圈定煤层采空（塌陷）区； ◆陡倾角、断层、岩脉等地质构造探测。 二、高密度电法简介 其原理与普通电阻率法相同，不同的是在观测中设置了高密度的观测点，工作装置组合实现了密点距陈列布设电极，是一种阵列勘探方法，现场测量时只需将全部电极（几十至上百根）置于测点上，然后利用程控电极转换开关和微机工程电测仪便可实现数据的快速和自动采集，增加了空间供电和采样的密度，提高了纵、横向分辨能力和工作效率。 在众多直流电阻率方法中，高密度电阻率法以其工作效率高、反映的地电信息量大、工作成本低、测量简便等突出优势，在物探领域中发挥着越来越重要的作用。主要应用于： ◆寻找地下水、管线探测、岩土工程勘察； ◆煤矿采空区调查，煤矿井下富水性探测； ◆水库大坝的坝体稳定性评价、坝基渗漏勘查、堤坝裂缝检测、建筑地基勘探； ◆涵洞和溶洞位置勘查、岩溶塌陷和地裂缝探测 三、矿井直流电法简介 主要应用于井下，其原理与地面直流电法相似，不同之处为：矿井直流电法属全空间电法勘探、采用本安防爆设备，它以岩石的电性
Unit1 大一新生日记 星期日 从家里出发后，我们开车开了很长一段时间才到达我住的宿舍楼。我进去登记。宿舍管理员给了我一串钥匙，并告诉了我房间号。我的房间在6楼，可电梯坏了。等我们终于找到8号房的时候，妈妈已经涨红了脸，上气不接下气。我打开门锁，我们都走了进去。 但爸爸马上就从里面钻了出来。这个房间刚刚够一个人住，一家人都进去，肯定装不下。我躺在床上，不动弹就可以碰到三面墙。 幸亏我哥哥和我的狗没一起来。 后来，爸爸妈妈就走了，只剩下我孤零零一个人。周围只有书和一个箱子。接下来我该做什么？ 星期一 早上，有一个为一年级新生举办的咖啡早茶会。我见到了我的导师，他个子高高的，肩膀厚实，好像打定了主意要逗人开心。 “你是从很远的地方来的吗？”他问我。他边说话边晃悠脑袋，咖啡都洒到杯托里了。“我家离爱丁堡不太远，开车大约6个小时，”我说。 “好极了！”他说，接着又走向站在我旁边的那个女孩儿。“你是从很远的地方来的吗？”他问。但不等那女孩儿作出任何回答，他就说到，“好极了！”然后就继续向前走。他啜了一口咖啡，却惊讶地发现杯子是空的。 妈妈打来电话。她问我是不是见到了导师。 星期二 我觉得有点儿饿，这才意识到我已经两天没吃东西了。我下楼去，得知一天三餐我可以在餐厅里吃。我下到餐厅排进了长队。 “早餐吃什么？”我问前面的男生。 “不知道。我来得太晚了，吃不上早餐了。这是午餐。”
午餐是自助餐，今天的菜谱是鸡肉、米饭、土豆、沙拉、蔬菜、奶酪、酸奶和水果。前面的男生每样儿都取一些放到托盘上，付了钱，坐下来吃。 我再也不觉得饿了。 妈妈打电话来。她问我有没有好好吃饭。 星期三 早上9点钟我要去听一个讲座。我醒时已经8:45了。竟然没有人叫我起床。奇怪。 我穿好衣服，急匆匆地赶到大讲堂。我在一个睡眼惺忪的女生旁边坐下。她看了看我，问：“刚起床？”她是怎么看出来的？ 讲座进行了1个小时。结束时我看了看笔记，我根本就看不懂自己写的字。 那个女生名叫苏菲，和我一样，也是英语文学专业的学生。她看起来惊人地聪明。听完讲座后我们一起闲聊。她告诉我在空档年( 高中毕业后等着上大学的一年) 里，她已经把这学期书单上的书都读完了。她给我留下了深刻的印象，我觉得自己太无知了，甚至不配跟她呼吸同样的空气。 妈妈来电话问我睡得好不好。 星期四 今天是新生集会（社团招新活动）。我和苏菲跑去看看我们能加入几个俱乐部。我们俩都认为我们应该结交很多朋友，所以我报名参加了交谊舞俱乐部、人工智能协会、手铃俱乐部和极限运动俱乐部。苏菲则报名参加了业余剧社和莫扎特合唱团。 我不知道我和苏菲还能不能继续做好朋友。 妈妈来电话。她告诉我哥哥曾试图把我在家住的那间卧室租出去。妈妈向我保证只要我需要，那房间永远是我的。她还说那是我的家，他们都非常想我，尤其是我的狗。我一下子就哭了起来。 星期五 早上我去了图书馆。可是好像我需要一个能验明我身份的证件才能进图书馆。不知为什么，我必须发誓不损坏书籍、不违反图书馆的规定，否则我就要被当作罪犯被送进监狱。（什么！？就因为说话声音太大？）图书馆看起来很古老，学校以此为豪。 今晚有个迪斯科舞会，可我已经没有干净衣服穿了。我只知道把脏衣服扔进衣篮中，但并不清楚衣服是如何洗净，熨平并叠好放进衣柜里的。也许妈妈快来电话了。