Investigation of the conjectured nucleon deformation at low momentum transfer

人教版高二英语科研项目实施困难重重练习题30题含答案解析1. In the implementation of scientific research projects, effective ______ among team members is crucial for the success.A. communicationB. transportationC. constructionD. destruction答案解析：A。

本题考查词汇辨析。

A选项“communication”意为沟通，在科研项目中，团队成员间有效的沟通对项目成功很关键。

B 选项“transportation”是运输的意思，与科研项目中的人员互动无关。

C 选项“construction”表示建设，与题意不符。

D选项“destruction”是破坏的意思，明显不符合语境。

2. When allocating resources in a scientific research project, we should first consider the ______ of each part.A. importanceB. happinessC. sadnessD. angriness答案解析：A。

这题考查词汇。

A选项“importance”重要性，在分配资源时，首先要考虑各部分的重要性。

B选项“happiness”快乐、C 选项“sadness”悲伤、D选项“angriness”愤怒，这三个选项都是表示情绪的词汇，与资源分配毫无关系。

3. The lack of ______ in a scientific research project may lead to the waste of resources.A. managementB. amusementC. movementD. measurement答案解析：A。

Estim ation of B iological N itrogen Fixation Capacity by Sugarcane U sing15NY ANG Rong 2zhong1,23,T AN Yu 2mo 2,G U I Yi 2yun 1,T AN Fang 1,L I Yang 2rui2,31.Guangxi Sugarcane Research Institute,N anning 530007;2.Sugarcane Research Center ,Chinese Acade m y of Agricultural Science,N anning,530007;3.Guangxi Acade m y of Agricultural Sciences,N anning,530007Abstrac t [O bjecti ve]The study ai m ed t o reveal the bi ol ogical nitr ogen fixati on capacity by sugarcane fr o m B razil under the ecol ogical conditi ons of Guangxi,and t o p r ovide reference for study on the bi ol ogical nitr ogen fixati on capacity by sugarcane and related generalizati on and applicati on .[M ethod]The 15N is ot opic fertilizer was s olely app lied on plants of three sugarcane cultivars planted in greenhouse with no other fertilizer f or ms applied,meanwhilevirus 2free ste m seedlingwas regarded as contr ol,t o measure their bi ol ogical nitr ogen fixati on capacity using 15N is ot ope .[Result]The nitr ogen fixati on rate of B8fr o m B razil reached 26.91%,while Guitang 11and R I C16p resented no or poor nitr ogen fixati on capacity .[Conclusi on]The sugarcane cultivar B8fr o m B razil sho wed s o me nitr ogen fixati on capacity under the ecol ogical conditi ons of Guangxi .Key wo rds Sugarcane;B i ol ogical nitr ogen fixati on;15N is ot opeReceived:June 2,2008 Accep ted:June 14,2008Supported by Nati onal Natural Science Foundati on of China (30260054;30660085);Key Pr oject of Guangxi Academy of Agricultural Sciences (2004002)and Natural Science Foundati on in Guangxi Zhuang Aut onomous Regi on (0639011).3Corres ponding author .E 2mail:r ozyang@ Sugarcane industry in Guangxi has occup ied an i m por 2tant position in total sugar industry in China for a long ti m e .Recent years yield of both the sugarcane and sucr ose in Guangxi accounted for 60%of the total in China .Ho wever,the cost of sugarcane p r oducti on in Guangxi is al w ays higher than that in the countries with advanced sugarcane industry containing B razil and Australia,which results not only fr o m natural p r oduction conditi ons,but als o fr o m excessive fertil 2izer app licati on .The nitr ogen app licati on a mount in sugar 2cane p r oduction at ho me was 500-700kg/h m 2[1-2],in s o me other countries including Australia,Thailand and I ndia was100-200kg/h m 2[3-5].The sugarcane yield in B razilreached about 80t/h m 2,but the cost was just 1/10of that in Guangxi due t o the app licati on of sugarcane cultivars with ni 2tr ogen fixati on capacity and corres ponding nitr ogen fixati on technique in B razil,which made the N fertilizer app licati on a mount was greatly l o wer than the N a mount in sugarcane p lants abs orbing fr o m the s oil when harvested .Thus,the study focusing on the nitr ogen fixation technique of sugarcane may contribute to the decrease of fertilizer app licati on a mounts in sugarcane p r oduction,further avail t o reduce sug 2arcane p r oducti on cost and envir on ment pollution and i m 2p r ove co mpetitive abilities in sugarcane industry .To reveal the bi ol ogical nitr ogen fixati on capacity by sugarcane fr o m B razil under the ecological conditi ons of Guangxi and p r ovide reference for study on the bi ol ogical nitr ogen fixati on capacity by sugarcane and related generalizati on and app lication,weconducted a 15N is ot ope dilution test in the p r ocess of stud 2ying on the nitr ogen fixation characteristics of sugarcane .M a te ri a ls and M e tho dsThe sugarcane cultivars for test were Guitang 11,ROC 16and B8,a mong which B8with nitr ogen fixation capacity were intr oduced fr o m B razil .The sugarcane cultivars for testwere samp led fr o m the regi ons with no N fertilizer app lied inN sensitivity test in the p revi ous year .The trial was carried out in glasshouse with five repeats for each treat m ent .Plants of each cultivar for test were p lanted int o 2barrels with three p lants for each barrel .Water for irrigati on is deep phreatic water that meets drinking water standard .The res pective 60kg unifor m s oil was p laced into each 55L barrel .The fertili 2ty situation for the tested s oil was as follo wing:pH 5.9,or 2ganic matter 1.4%,t otal N 0.11%,available N 56mg/kg,available P 22mg/kg,available N 166mg/kg .I n the nitr o 2gen fixation capacity test,the contr ol was hot 2water virus 2free ste m seedlings and the s oil was sterilized at 121℃for1h .2g a mmoniu m sulfate containing 10.64%15N (p r ovid 2ed by Shanghai Research I nstitute of Petr oche mical Technol 2ogy )was app lied for each treat ment at j ointing stage and oth 2er manage ments were in accordance with r outine p r ocedures .To ensure the nor mal function of nitr ogen fixation by the sug 2arcane with nitr ogen fixation capacity,40g/h m 2molybdenu mfertilizer was s p rayed once entering j ointing stage [6].Accord 2ing to the reports of Oliveira [7],t w o +2leaves of sugarcane p lants (t wo leaves for each barrel )were samp led at latter ma 2ture stage to measure the contents of N and 15N using the ZHT203Mass Spectr ograph fr o m I nstitute of Genetics and Physiology,Hebei Acade my of Agriculture and Forestry Sci 2ences .The average values of the yield data were used to cal 2culate the p l ot value of tested sugarcane cultivars .The for mula for calculating nitr ogen fixation capacity:%Ndfa =100-15N ato m percent excess in nitr ogen fix 2ati on p lant/15N ato m percent excess in non 2nitr ogen fixation p lant .15N at o m percent excess =15N ato m percent -0.3663.Re sults and Ana l ysisN conten t and 15N%i n the leaves of different sugarcane cultivarsA s sho wn in Table 1,N content varied in the leaves fr o m different sugarcane cultivars .I n three test cultivars,maxi mu m N content was observed in the leaves of Guitang 11foll o wed by ROC16,thirdly the B8fr o mB razil .Analysis of variance sho wed that significant differences were observed a 2Agr onom yAgri cultura l Sci ence &Techno l o gy,2008,9(2):154-156Copyri ght Ζ2008,I nfo r m a ti o n I nstitute of HAAS.A ll ri ghts re se rved.mong various cultivars,a mong which the N content in leaves of Guitang11was significantly higher than that in leaves of B8.By contrast,no significant differences in15N%were de2 tected a mong the different cultivars.According t o the N con2 tent,15N%p resented an increasing trend with the increase of N content in leaves,the variation coefficients a mong N contents were lo wer than that of15N%.Table1　N content and15N%i n the leaves of d i fferen t sugarcane culti2 vars%Test cultivarN content in leavesContent Variati on coefficient15N%ContentVariati on coefficientGuitang111.001A#6.611.074a9.33 ROC160.931AB7.501.057a11.21B80.855B4.520.971a8.03#denotes the result of multi p le comparis on.The data were used for variance analysis after conversi on arc2sine.Table2　N itrogen f i xa ti on rates of the three sugarcane culti vars i n di f2 ferent repeats%NdfaCultivar Guitang11ROC16B8Repeat103012.85Repeat20　019.71Repeat30　010.67Repeat432.0440.5546.84Repeat518.6139.7244.503denotes that the%Ndfa value is negative and regarded as0.N fi xa tion capacities of di fferent cultivarsFor the three test cultivars,just the B8fr o m B razil suc2 cessfully fixed N fr o m air in5repeats,the maxi mu m and mini m u m N fixation rates were46.84%and10.67%,re2 s pectively,with an average of26.91%,suggesting that the intr oduced cultivar has s o me nitr ogen fixati on capacity under the ecol ogical conditi ons of Guangxi.Fr o m the nitr ogen fixa2 tion rates in different repeats,the nitr ogen fixation capacity of B8varied greatly,which indicats that biological nitr ogen fixation capacity of B8is easily influenced by ecol ogical mi2 cr oenvir on ment.The results als o sho wed that other t wo culti2 vars just sho wed nitr ogen fixation capacity in1or2repeats, indicating s o me nitr ogen fixation capacity of Guitang11and ROC16.The ROC16p lanted in large scale at ho me in re2 cent years,the average nitr ogen fixation rate in the t wo re2 peats p resenting nitr ogen fixation capacity was3.51%, which indicate the poor nitr ogen fixation capacity of this cul2tivar.Thr ough Guitang11sho wed nitr ogen fixation capacity in t wo repeats,but the average nitr ogen fixati on rate was just negative2.47%,indicating that Guitang11has no nitr ogen fixati on capacity.Concl usi o nThe p resent study revealed that sugarcane cultivar B8 fr o m B razil sho wed s o me fixation capacity under the ecologi2 cal conditions of Guangxi,while other cultivars p resented no or poor nitr ogen fixation capacity,which is consistent with other gr oup s,that is t o say nitr ogen fixati on capacity is obvi2 ously influenced by different cultivars and envir on2 ments[7-10].Mean while,under the ecological conditi ons of Guangxi,the sugarcane cultivars with nitr ogen fixati on po2 tential p resented poor,which may be related with the differ2 ent endophytic diaz otr ophs and s oil envir on ment[6].R efe rence s[1]T AN Y M,WANGL W,WANG TS,et al.Study on the sensitivity t o nitr o2gen of sugarcane nitr ogen2fixed variety RB722454in the field[J].Guan2 gxi Sugarcane&Canesugar,2002(1):12-15.(in Chinese).[2]Z HANG Y B,WU ZK,L I U S C,et al.Study and applicati on of main fac2t ors of s pring sugarcane planted in arid area[J].Sugarcane,2002(4):16 -19.(in Chinese).[3]MUT HUK U MARAS A MY R,RE NAT H I G,LAKS H M I N ARASI M HAN C.I nfluence of N fertilizati on on the is olati on of Acetobacter diazotr ophicusand Herbaspirillu m s pp.fr o m I ndia sugarcane varieties[J].Bi ol Fertil S oil,1999,29:157-164.[4]MAG AREY RC.Devel opment of the Australian sugar industry:1970-2000[M]//L I Y R,S OLO MON S.Sustainable sugarcane and sugar pr o2 ducti on technol ogy.Beijing:China Agriculture Press,2004:84-88. [5]LEE TSG.Sugarcane industry in Brazil[M]//L I Y R,S OLO MON S.Sustainable sugarcane and sugar pr oducti on technol ogy.Beijing:China Agriculture press,2004:29-30.[6]ROBERT MB,URQU I A G A S,BRUNO JR,et al.Endophytic nitr ogenfixati on in sugarcane:Psent kno wledge and future applicati ons[J].Plant and S oil,2003,252:139-149.[7]OL I V EI RA AL M,URQU I A G A S,DOBEREI N ER J,et al.The effect ofinoculating endophytic N22fixing bacteria on micr opr opagated sugarcane plants[J].Plant S oil,2002,242(2):205-215.[8]L I M A E,BODDEY R M,DOBEREI N ER J.Quantificati on of bi ol ogical ni2tr ogen fixati on ass ociated with sugarcane using a15N aided nitr ogen bal2 ance[J].S oil Bi ol Bi oche m,1987,19:165-170.[9]URQU I A G A S,CRUZ K HS,BODDEY R M.Contributi on of nitr ogen fixa2ti on t o sugarcane:Nitr ogen215and nitr ogen balance esti m ates[J].S oil Sci S oc Am J,1992,56:105-114.[10]Y ONEY A MA T,MURAOK A T,KI M T H,et al.The natural15N abun2dance of sugarcane and neighbouring plants in Brazil,the Phili ppines and M iyako(Japan)[J].Plant S oil,1997,189:239-244.15N测定甘蔗生物固氮能力研究杨荣仲1,23,谭裕模2,桂意云1,谭芳1,李杨瑞2,3　(1.广西甘蔗研究所,广西南宁530007;2.中国农科院甘蔗研究中心,广西南宁530007;3.广西农业科学院,广西南宁530007) 国内、外甘蔗生产中的氮肥施用量分别为500～750、100～200kg/h m2。

嫌疑与证据英语作文模板Title: Suspicion and Evidence。

Introduction。

In the field of law and justice, the concepts of suspicion and evidence play a crucial role in determining the guilt or innocence of an individual. Suspicion refers to the belief or feeling that someone is involved in a criminal activity, while evidence is the information or material that proves or disproves a fact. This essay will explore the significance of suspicion and evidence in the legal system, their impact on the process of investigation and trial, and the ethical considerations surrounding their use.The Role of Suspicion。

Suspicion is often the starting point of a criminal investigation. Law enforcement agencies and legal authorities rely on suspicion to identify potential suspects and gather information about their possible involvement in a crime. However, it is important to note that suspicion alone is not sufficient to establish guilt. In a democratic society, individuals are presumed innocent until proven guilty, and suspicion should not be used as a basis for prejudgment or discrimination.The process of forming suspicion involves a careful analysis of various factors, including witness statements, circumstantial evidence, and behavioral patterns. Law enforcement officers and investigators must exercise caution and objectivity in their approach to avoid jumping to conclusions based on personal biases or stereotypes. Moreover, suspicion should be supported by reasonable grounds and factual information to justify the initiation of a criminal investigation.The Significance of Evidence。

• 1198•中国病原生物学杂志2020年10月第15卷第10期Journal o f Pathogen B iology Oct. 2020，Vol. 15* No. 10D()I：10. 13350/j. cjpb. 201014 •调查研究•2016 —2019年重症科多耐药菌分布研究*梅海峰，梁宗敏，孙文斌，邰慧宇，朱尚，薛露，朱志云…(泰州市人民医院重症医学科.江苏泰州225300)【摘要】目的调查医院重症科多耐药菌分布情况.指导临床抗感染防治。

方法收集2016 — 2019年重症科患者2 332例临床资料.分离多药耐药菌。

采用全自动微生物鉴定仪鉴定病原菌类型，分析病原菌耐药性。

采用P C R扩增检测 多重耐药鲍曼不动杆菌耐药基因分布情况。

采用统计学分析影响感染发生相关因素。

结果2016 — 2019年重症科患者多重耐药菌感染率分别为2. 10%、2. 80%、2. 20%和3. 27%。

经卡方检验，抗菌药物使用种类、住院时间、气管插 管、机械通气时间、合并恶性肿瘤是影响多药耐药菌感染发生的因素（P<0. 05)。

61株多药耐药菌中，鲍曼不动杆菌27 株、金黄色葡萄球菌15株、铜绿假单胞菌9株、肺炎克雷伯菌4株及其他多药耐药菌6株，分别占44. 26%、24. 59%、U. 75%、6. 56%、9. 84%;分离(51株多药耐药菌.在痰液、尿液、血液、伤口、脏器腔隙、烧伤皮肤、腹水液、脑脊液、血管导 管、胆汁及其他标本中的分离率分别为 4.86%、2. 34%、2. 36%、2. 19%、2.23%、2.06%、1. 99%、1. 96%、1. 89%、0. 83% 和4.55%;27株多药耐药鲍曼不动杆菌中，27株（100.00%)OXA-51检测阳性，27株（100.00%)qaC E A l-s u l l检测阳 性，20 株（74. 07%)OXA-23 检测阳性，13 株（48. 15%)AmpC 检测阳性，5 株（18. 52%)TEM检测阳性，4 株（14. 81%)D H A检测阳性，2株（7. 41%)PE R检测阳性；此外，OXA-24、OXA-58、IM P-l、IMP-4、V IM-2在重症科分离的多药耐药鲍曼不动杆菌中均未检出。

9Organic CompoundsWhile there has always been some interest in the nature of the organic com-pounds in seawater,identification of actual compounds has progressed slowly because of the low concentrations present.With a total organic carbon concen-tration of0.5–1.5mg/l of carbon,the total concentration of any single organic compound is likely to be less than10–7M.Therefore,in the past,identification of individual compounds has been limited to those few for which specific, sensitive chemical methods existed.These methods were usually spectropho-tometric,and were often developments of methods originally used in clinical chemistry.The advent of the newer physical methods of separation and identification, together with the impetus given to thefield by the imposition of anti-pollution legislation,has resulted in aflood of new and often unproven methods.While most of these methods were specifically designed to measure materials added to the environment by man’s activities,in many cases they have added greatly to our knowledge of the naturally occurring compounds as well.Until the advent of modern instrumental methods of analysis,the best we could hope to do was to measure the amounts of certain broad classes of compounds present,as,for example,the total protein or total carbohydrate.Using the newer methods,such as gas chromatography,liquid–liquid chro-matography,fluorometry,and mass spectrometry,it is possible to measure many compounds at the parts-per-billion level,and a few selected compounds with special characteristics at the parts-per-trillion level.Even with these sen-sitivities,however,a considerable concentration must usually be undertaken to permit the chemical or physical fractionation necessary to render thefinal analyses interpretable.A major effort has therefore been expended on the study of methods of separation and concentration,and this is discussed further in Chap.8.A problem which has been less well recognised is that of contamination in sampling and sample handling.The oceanographic vessel itself is a major source of contamination;from the moment that the ship stops on station, a surfacefilm of oil,flakes of metal and rust spreads out in all directions. The means of sampling also often acts as a source of contamination.Once the sample is on board,along with the normal problems of contamination through sample handling and through high blank values from the reagents used,we3669Organic Compounds must also attempt to cope with chemical and biological changes occurring during storage,since many of the modern instruments are not easily taken to sea.In environmental chemistry,the work of Analyst does not begin with the delivery of the sample to the laboratory;every aspect of sampling,storage, and pretreatment must be considered part of the analyst’s domain.This is discussed further in Chap.1.HydrocarbonsProbably the most studied group of organic compounds in seawater is the hydrocarbons,not because of the importance of the naturally occurring ma-terials,but because of the continuing threat of large-scale pollution.However, the methods devised for the measurement of anthropogenic hydrocarbons will also measure the natural materials.A major problem,not altogether solved,is that of distinguishing between the two sources.There have been many reviews of analytical methods for hydrocarbons, particularly those given in[1–11].Burgess[538]has reviewed the charactisation and identification of organic toxicants in marine waters9.1Aliphatic Hydrocarbons9.1.1SpectrofluorometryFam et al.[11]determined hydrocarbons in run-off water from catchments in San Francisco Bay using liquid chromatography and high-resolution gas chromatography.Wade and Quinn[12]measured the hydrocarbon content of sea surface and subsurface samples.Hydrocarbons were extracted from the samples and analysed by thin-layer and gas–liquid chromatography.The hydrocarbon con-tent of the surface micro layer samples ranged from14to599µg/l with an average of155µg/l,and the concentration in the subsurface samples ranged from13to239µg/l and averaged73µg/l.Several isolated hydrocarbon frac-tions were analysed by infrared spectrometry and each fraction was found to contain a minimum of95%hydrocarbon material,including both alkenes and aromatics.9.1.2Dynamic Headspace AnalysisMay et al.[13]have described a gas chromatographic method for analysing hydrocarbons in marine sediments and seawater which is sensitive at the9.1Aliphatic Hydrocarbons367 sub microgram per kilogram level.Dynamic headspace sampling for volatile hydrocarbon components,followed by coupled-column chromatography for analysing the nonvolatile components,requires minimal sample handling,thus reducing the risk of sample component loss and/or sample contamination. The volatile components are concentrated on a Tenax gas chromatographic precolumn and determined by gas chromatography or gas chromatography–mass spectrometry.Other workers have discussed the application of dynamic headspace analysis to the determination of aliphatic hydrocarbons in seawater[14–18].A second system,the removal of volatiles by vacuum,can be set up in two ways;either as aflow-through or as a batch process.As aflow-through process, the sample is drawn continuously through the system,and the gases taken off by the vacuum pass through a sampling loop.Periodically,the material in the loop is injected into the gas chromatograph.In this manner it is possible to derive almost continuous profiles of volatile hydrocarbon concentrations[19].In the batch mode,a larger sample can be treated over a longer period, and the volatiles collected by cold-trapping or adsorption.These techniques are not as fast asflow-through sampling,nor do they permit semi-continuous profiling,but they result in greater concentrations of the hydrocarbons,and thus in greater sensitivity[20].The third technique,stripping-out,is by far the most common.In this tech-nique,an inert gas is bubbled through the sample to remove the volatile ma-terials.When the concentration of hydrocarbons is great enough,as,perhaps, after a petroleum spill,the emergent gas stream can be sampled directly[21]. This is seldom the case in true oceanic samples,however,and some form of concentration is needed.It is possible to collect the volatiles in a cold trap[22].A more favoured technique is the collection of the gases by adsorption on some support such as one of the Chromosorbs,or Tenax GC[13,22,23].The volatiles are then desorbed by heating and injected into a gas chromatograph.Of the three general methods,the last seems to be the most practical.Theo-retically,with high enough concentrations of hydrocarbons,thefirst method, the headspace analysis,should be both the most accurate and the easiest to cal-ibrate.Operationally,it leaves much to be desired both because of the problems of sensitivity and those of the accommodation of the larger molecules in water. The second method,vacuum degassing,requires much more equipment than the third method and requires that large amounts of water vapor be removed before the sample is injected into the gas chromatograph.The last method is so much less complicated that even with its calibration problems it has been adopted almost universally.While the gases used in stripping are usually air,nitrogen,or helium, electrolytically evolved hydrogen has been used as a collector for hydrocar-bons[24].In this technique the gas is not passed through a column of adsor-bent,but instead collects in the headspace of the container.Since the volume3689Organic Compounds of seawater and of hydrogen is known,the hydrocarbon concentration in the headspace can be used to calculate the partition coefficients and the concen-trations of hydrocarbon in the seawater.This method is capable of determining 1µg/l of volatile hydrocarbons in seawater.9.1.3Raman SpectroscopyAhmadyian and Brown[25]have used laser Raman spectroscopy to identify petroleums.9.1.4Flow CalorimetryZsolnay and Kiel[26]have usedflow calorimetry to determine total hydro-carbons in seawater.In this method the seawater(1litre)was extracted with trichlorotrifluoroethane(10ml)and the extract was concentrated,first in a vac-uum desiccator,then with a stream of nitrogen to10µl.A50µl portion of this solution was injected into a stainless steel column(5cm×1.8mm)packed with silica gel(0.063–0.2mm)deactivated with10%of water.Elution was ef-fected,under pressure of helium,with trichlorotrifluoroethane at5.2ml per hour and the eluate passed through the calorimeter.In this the solutionflowed over a reference thermistor and thence over a detector thermistor.The latter was embedded in porous glass beads on which the solutes were adsorbed with evolution of heat.The difference in temperature between the two thermistors was recorded.The area of the desorption peak was proportional to the amount of solute present.9.2Aromatic Hydrocarbons9.2.1SpectrofluorometryBooksh et al.[27]employed an excitation/emission matrix imaging spectroflu-orometer for quantitation of twofluorescent compounds,naphthalene and styrene,contained in ocean water exposed to gasoline.Multidimensional par-allel factor(PARAFAC)analysis models were used to resolve the naphthalene and styrenefluorescence spectra from a complex background signal and over-lapping spectral interferents not included in the calibration set.Linearity was demonstrated over2orders of magnitude for determination of naphthalene with a detection limit of8parts per billion.Similarly,nearly2orders of mag-nitude of linearity were demonstrated in the determination of styrene with an9.3Polyaromatic Hydrocarbons369 11ppb limit of detection.Furthermore,the synthesis of the EEM spectroflu-orometer and the PARAFAC analysis for unbiased prediction of naphthalene and styrene concentration in mixture samples containing uncalibrated spectral interferents was demonstrated.9.2.2High-Performance Liquid Chromatography(HPLC)By its very nature,the gas chromatograph is only useful with those compounds which can be made volatile in some pounds that are nonvolatile at the temperatures that can be achieved in the gas chromatograph injection port, or those that degrade and polymerise,will be left as a residue in the injection port or at the top of the column.For these compounds,high-performance liquid chromatography is the natural technique.The weak point of this technique has been the sensitivity of the detectors;the common commercially available detectors measure refractive index,and light absorption andfluorescence in the ultraviolet and visible.Of these,only thefluorescence detector can approach the sensitivity of the gas chromatograph detectors,and it is useful only for those few compounds that are naturallyfluorescent.There have also been attempts to link the liquid chromatograph toflame ionisation detectors and atomic absorption spectrometers.HPLC has been used,with an ultraviolet absorption detector set for254nm, for the determination of aromatic hydrocarbons and with aflow calorimeter for the detection of all hydrocarbons.Increased sensitivity and decreased inter-ference can be achieved with the ultraviolet absorption detector by measuring absorption at two wavelengths and using the ratios of the absorption at those wavelengths[28].9.3Polyaromatic HydrocarbonsHiltabrand[29]has investigated thefluorometric determination of polyaro-matic aromatic hydrocarbons in seawater.Payne[30]carried out afield investigation of benzopyrene hydrolysate induction as monitor for marine petroleum pollution.Isaaq et al.[31]isolated stable mutagenic ultraviolet photodecomposition products of benzo(a)pyrene by thin-layer chromatography.Fuoco et al.[539]has reported the analysis of priority pollutants in seawater using online supercriticalfluid chromatography,cryotrap gas chromatogra-phy–mass ing this system polynuclear aromatic hydrocarbons and polychlorobiphenyls were measured in seawater with recoveries better than75%.Law et al.[540]have recently reviewed methods for the analysis of polyaro-matic hydrocarbons in marine water.3709Organic Compounds 9.4Oil SpillsIn the early days of pollution research,many methods were investigated in the hope offinding a single technique which would infallibly link the deed and the doer,the oil spill and the leaking container.The research was aided by a number of cases in which the provenance was obvious;the Torrey Canyon and the Arrow incidents are two examples.Thus it was possible to study the changes brought about by weathering and to discover how these changes would hamper identification of the source of the spill.The difficulty of attempting such identification using only a single technique was clearly shown by the number of proposals to add radioactive or chemical labels to petroleum products as they were loaded into the tankers.Of the methods developed for the identification of hydrocarbon mixtures, only coupled gas chromatography–mass spectrometry holds any real promise of certain identification and this only at a prohibitive cost in time spent charac-terising minor peaks.It would be far more efficient to develop rapid screening procedures which would eliminate all but a few possibilities,and then use gas chromatography–mass spectrometry to isolate and identify a few key peaks to confirm the characterisation.This is precisely the scheme adopted indepen-dently by a number of laboratories.9.4.1SpectrofluorometryThis method was originally used to detect oil in surveys of oil in seawater (Zitko and Carson[32];Michalik and Gordon[33];Levy[34,35];Levy[36]).Van Duuren[37]examined the use of emission and excitation spectra in the identification of aromatic hyorocarbons.Contour diagrams offluorescence activity at various excitation and emission wavelengths have been used as a means of identifying petroleum residues.However,the main use offluorescence has been in the semi-quantitative determination of aromatic hydrocarbons by extraction into an organic solvent, followed by excitation at a standard wavelength and comparison with the emission from a chosen standard.These techniques have been studied by many workers[38–42].The difficulties in the use offluorescence for quantitative measurement of hydrocarbons are much like those for the ultraviolet absorption methods.Each compound has its own excitation and emission maxima,with thefluorescence quantum yields varying sometimes by an order of magnitude.Thus the amount of hydrocarbon reported by an analysis will depend upon the emission and ex-citation wavelengths chosen,and upon the compound selected as the standard.Petroleum products contain manyfluorescing compounds,e.g.,aromatic hydrocarbons,polycyclic aromatic hydrocarbons,and various heterocyclic9.4Oil Spills371 compounds.The use offluorescence technique and instrumentation has led to the use of this technique for the identification of crude and residual oil pollutants in a marine environment[43,44]and of motor oils and related petroleum products[45–48].Maher[49]usedfluorescence spectroscopy for monitoring petroleum hy-drocarbon contamination in estuarine and ocean waters.An ingenious variation on the standardfluorescence methods was proposed by Red’kin et al.[50].Water samples were extracted with non-polar solvents, transferred into hexane and the hexane solution frozen at77K.At that temper-ature the normally diffuse luminescence emission bands are present as sharp emission lines,making identification offluorescing compounds considerably simpler.In the case of a complex mixture,some separation by column or thin layer chromatography might be necessary.Second-order and fourth-order derivative synchronous spectrometry has been used tofingerprint crude oil and fuel oil spills in seawater[51].9.4.2Infrared SpectroscopyKawahara[52–54]has described an infrared spectroscopic method applicable to essentially nonvolatile petroleum products.Heavy residual fuel oils and asphalts are not amenable to gas chromatogra-phy and give similar infrared spectra.However,a differentiation can be made by comparing certain absorption intensities[52].Samples were extracted with chloroform,filtered,dried,and the solvent evaporated off at100◦C for a few minutes using an infrared lamp.A rock salt smear was prepared from the residue in a little chloroform,and thefinal traces of solvent removed using the infrared lamp.The method,which in effect compares the paraffinic and aromatic nature of the sample,involves calculation of the following absorption intensity ratios:•(13.88µm polymethylene chain)/(7.27µm methyl groups)•(3.28µm aromatic C–H)/(3.42µm aliphatic C–H)•(12.34µm aromatic rings)/(7.27µm methyl groups)•(6.25µm aromatic C–C)/(7.27µm methyl groups)•(12.34µm aromatic rings)/(13.88µm polymethylene chain)•(6.25µm aromatic C–C)/(13.88µm polymethylene chain)Peaks observed at5.90µm and8.70µm were thought to reflect oxidative effects on the asphaltic material,while asphaltic sulfoxide and sulfone were tentatively inferred from bands at9.76,8.66,and7.72µm.The12.34/13.88,12.34/7.27, and6.25/13.88µm ratios tended to show the greatest difference between dif-ferent samples.When the ratio12.34/7.27µm versus12.34/13.88µm were plot-ted graphically,the intermediate fuel oils behaved similarly[53].Weathering caused fuel oils to fall below the curve although with asphalts the effect was3729Organic Compoundssignificantly less.Since no prior purification was employed the method relies on an uncontaminated,unweathered sample of oil being available.Mattson and Mark[55,56]reported some criticism of Kawahara’s technique. They claim that evaporation of the solvent chloroform by infrared heating re-moves volatiles and causes large changes in the ratios.An oil sample was shown to suffer such alteration by the infrared during repeated analysis.The absorp-tion of all bands decreased nonuniformly between20and100%over a period of30min.They propose the application of internal reflection spectrometry as a rapid,direct qualitative technique requiring no sample pretreatment.In contrast to infrared spectrometry there is no decrease in relative sen-sitivity in the lower energy region of the spectrum,and since no solvent is required,no part of the spectrum contains solvent absorptions.Oil samples contaminated with sand,sediment,and other solid substances have been anal-ysed directly,after being placed between0.5mm23-reflection crystals.Crude oils,which were relatively uncontaminated and needed less sensitivity,were smeared on a2mm5-reflection crystal.The technique has been used to differ-entiate between crude oils from natural marine seepage,and accidental leaks from a drilling platform.The technique overcomes some of the faults of in-frared spectroscopy,but is still affected by weathering and contamination of samples by other organic matter.The absorption bands shown in Table9.1are important in petroleum product identification.Kawahara and Ballinger[53,57]has used their method to characterise a number of known and unknown petroleum samples.All of these studies used the normal transmission method to obtain infrared spectra;however, the feasibility of using internal reflection to obtain infrared spectra has been demonstrated by several groups(Mattson and Mark[55],Mark et al.[58], Table9.1.Absorption bands important in petroleum products identificationBand(µm)Compound3.23–2.78Water3.28Aromatic CH3.29–CH33.42>CH23.51>CH25.88>C=O6.25Aromatic C–C6.90>CH27.27–CH39.71>S=O,PO411.63Aromatic CH13.60Aromatic CH13.98Long chain–CH2–Source:Author’s ownfiles9.4Oil Spills373 Baier[59]).The advantage of the latter method is that chemical extraction of petroleum from such as sand and water is unnecessary.Pierre[60]has reported a study of the characterisation of the surface of oil slicks by infrared reflective spectroscopy.A double-beam spectrophotometer was modified for studying the reflectance spectra(at angles of incidence45◦, 60◦,70◦)of oil layers(20–30µm thick)on the surface of water using pure water as reference.Various other workers have discussed the application of this technique to oil spill analysis[61–63].9.4.3Gas ChromatographyVarious workers have discussed this technique[43,64–72].Ramsdale and Wilkinson[66]have identified petroleum sources of beach pollution by gas chromatography.Samples containing up to90%of sand or up to80%of emulsified water were identified,without pretreatment by gas chromatography,on one of a pair of matched stainless steel columns (750×3.2mm id)fitted with precolumns(100mm)to retain material of high molecular weight,the second column being used as a blank.The column packing is5%of silicone E301on Celite(52–60mesh),the temperature is programmed at5◦C per minute from50◦C to300◦C,nitrogen was used as carrier gas,and twinflame ionisation detectors were used.Adlard et al.[74]improved the method of Ramsdale and Wilkinson[66] by using an S-selectiveflame photometric detector in parallel with theflame ionisation detector.Obtaining two independent chromatograms in this way greatly assists identification of a sample.Evaporative weathering of the oil samples has less effect on the information attainable byflame photometric detection than on that attainable byflame ionisation detection.A stainless steel column(1m×3mm id)packed with3%of OV-1on A WDMCS Chro-mosorb G(85–100mesh)was used,temperature programmed from60◦C to 295◦C per minute with helium(35ml/min)as carrier gas,but the utility of the two-detector system is enhanced if it is used in conjunction with a stainless steel capillary column(20×0.25mm)coated with OV-101and temperature programmed from60◦C to300◦C at5◦per minute,because of the greater detail shown by the chromatograms.Brunnock et al.[67]have also determined beach pollutants.They showed that weathered crude oil,crude oil sludge,and fuel oil can be differentiated by the n-paraffin profile as shown by gas chromatography,wax content,wax melting point,and asphaltene content.The effects of weathering at sea on crude oil were studied;parameters unaffected by evaporation and exposure are the contents of vanadium,nickel,and n-paraffins.The scheme developed for the identification of certain weathered crude oils includes the determination of these constituents,together with the sulfur content of the sample.3749Organic Compounds Adlard and Matthews[75]applied theflame photometric sulfur detector to pollution identification.A sample of the oil pollutant was submitted to gas chromatography on a stainless steel column(1m×3mm)packed with3%of OV-1on A WDMCS Chromosorb G(85–100mesh).Helium was used as carrier gas(35ml/min)and the column temperature was programmed from60◦C to295◦C at5◦per minute.The column effluent was split between aflame ionisation and aflame photometric detector.Adlard and Matthews[75]claim that the origin of oil pollutants can be deduced from the two chromatograms. The method can also be used to measure the degree of weathering of oil samples.Boylan and Tripp[76]determined hydrocarbons in seawater extracts of crude oil and crude oil fractions.Samples of polluted seawater and the aqueous phases of simulated samples(prepared by agitation of oil–kerosene mixtures and unpolluted seawater to various degrees)were extracted with pentane. Each extract was subjected to gas chromatography on a column(8ft×0.06in) packed with0.2%of Apiezon L on glass beads(80–100mesh)and temper-atures programmed from60◦C to220◦C at4◦C per minute.The compo-nents were identified by means of ultraviolet and mass spectra.Polar aro-matic compounds in the samples were extracted with methanol-dichlorome-thane(1:3).Investigations on pelagic tar in the North West Atlantic have been car-ried out using gas chromatography[77].This report collects together the results of various preliminary investigations.It is in the Sargasso Sea where the highest concentrations(2–40mg/m2)occur,and on beaches of isolated islands,such as Bermuda.These workers discuss the occurrence,structure, possible sources,and possible fate of tar lumps found on the surface of the ocean.Zafiron and Oliver[78]have developed a method for characterising envi-ronmental hydrocarbons using gas chromatography.Solutions of samples con-taining oil were separated on an open-tubular column(50ft×0.02in)coated with OV-101and temperature programmed from75◦C to275◦C at6◦C per minute;helium(50ml/min)was used as carrier gas and detection was byflame ionisation.To prevent contamination of the columns from sample residues the sample was injected into a glass-lined injector assembly,operated at175◦C, from which gases passed into a splitter before entering the column.Analysis of an oil on three columns gave signal intensity ratios similar enough for direct comparison or for comparison with a standard.The method was adequate for correlating artificially weathered oils with sources and for differentiating most of30oils found in a sea port.Garra and Muth[80]and Wasik and Brown[81]characterised crude,semi-refined,and refined oils by gas chromatography.Separation followed by dual-response detection(flame ionisation for hydrocarbons andflame photometric detection for S-containing compounds)was used as a basis for identifying oil samples.By examination of chromatograms,it was shown that refinery9.4Oil Spills375 oils can be artificially weathered so that the source of the oils can be deter-mined.Hertz et al.[79]have discussed the methodology for the quantitative and qualitative assessment of oil spills.They describe an integrated chromato-graphic technique for studies of oil spills.Dynamic headspace sampling, gas chromatography,and coupled-column liquid chromatography are used to quantify petroleum-containing samples,and the individual components in these samples are identified by gas chromatography and mass spectrometry.Rasmussen[82]describes a gas chromatographic analysis and a method for data interpretation that he has successfully used to identify crude oil and bunker fuel spills.Samples were analysed using a Dexsil-300support coated open tube(SCOT)column and aflame ionisation detector.The high-resolution chromatogram was mathematically treated to give“GC patterns”that were a characteristic of the oil and were relatively unaffected by moderate weath-ering.He compiled the“GC patterns”of20crude oils.Rasmussen[82]uses metal and sulfur determinations and infrared spectroscopy to complement the capillary gas chromatographic technique.The gas chromatograms of most oil samples examined had similar basic features.All were dominated by the n-paraffins,with as many as13resolved but unidentified smaller peaks appearing between the n-paraffin peaks of adjacent carbon numbers.Each oil had the same basic peaks,but their relative size within bands of one carbon number varied significantly with crude source.9.4.4Gas Chromatography–Mass Spectrometry(GC–MS)In some cases it is necessary unambiguously to identify selected components separated during gas chromatographic examination of oil spill material.Such methods are needed from the standpoint of the enforcement of pollution control laws.The coupling of a mass spectrometer to the separated components emerging from a gas chromatographic separation column enables such positive identifications to be made.Smith[83]classified large sets of hydrocarbon oil infrared spectral data by computer into“correlation sets”for individual classes of compounds.The correlation sets were then used to determine the class to which an unknown compound belongs from its mass spectral parameters.A correlation set is constructed by use of an ion-source summation,in which a low resolution mass spectrum is expressed as a set of numbers representing the contribution to the total ionisation of each of14ion series.The technique is particularly valuable in the examination of results from coupled gas chromatography–mass spectrometry of complex organic mixtures.Walker et al.[84]examined several methods and solvents for use in the extraction of petroleum hydrocarbons from estuarine water and sediments, during an in situ study of petroleum degradation in sea water.The use of。

EVALUATION OF ZEFREH DOLOMITE (CENTRAL IRAN)FOR PRODUCTION OF MAGNESIUM VIA THE PIDGEON PROCESSBehzad Mehrabi 1,Masud Abdellatif 2,and Fariborz Masoudi 31Geology Department,Tehran Tarbiat Moallem University,Tehran,Iran 2Mintek Corporate,Randburg,South Africa 3Faculty of Earth Sciences,Shahid Beheshti University,Tehran,IranThis study evaluates the production of magnesium metal from the Zefreh dolomite ore of Central Iran using the Pidgeon process.The investigation consisted of mineralogical and chemical characterization of the dolomite ore,calcining,chemical characterization,LOI (loss on ignition)determination,reduction tests on the calcined dolomite (dolime),using Iranian (Semnan)ferrosilicon and mineralogical,and chemical characterization of the reactants and products.Calcining of dolomite samples was carried out at approximately 1400 C in order to remove CO 2,moisture,and other easily volatilized impurities.The dolime was then milled,along with ferrosilicon,thoroughly mixed,and briquetted.The briquettes were heated at 1125 C–1150 C and 500Pa in a tube reactor for 10–12hours to extract the magnesium.The ferrosilicon to dolime ratio was determined based on the chemical analyses of the two reactants,using as a guide,and Mintek’s Pyrosim software package.Magnesium extraction varied with ferrosilicon addition and with the dolime used,and reach about 80%under optimal conditions.The levels of major impurities encountered in the magnesium crown were similar to those in the crude metal production.Keywords :Mg metal,Pidgeon process,Semnan ferrosilicon,silicothemric,Zefreh dolomiteINTRODUCTIONThe use of metallic magnesium is growing very rapidly,mainly for the production of light metal alloys,with applications in the aircraft and automotive industry,desulphurization of iron and steel,production of light weight mainly Al–Mg alloys,and some chemical applications (Habashi 1997).Approximately,80%of the worlds demand for magnesium is currently supplied by China and nearly 95%of the primary magnesium output of China is produced using the Pidgeon pro-cess primarily because of the low labor and energy costs as well as lax environmental controls (Ding and Zang 2001;Zang and Ding 2001;Cherubini,Raugei,and Ulgiati 2008).There are two major industrial processes for magnesium metal production.The first involves thermal reduction of magnesium oxide,mainly from dolomite,withAddress correspondence to Behzad Mehrabi,Geology Department,Tarbiat Moallem University,No.49,Mofateh Ave.,Tehran,15614,Iran.E-mail:mehrabi@tmu.ac.irMineral Processing &Extractive Metall.Rev.,33:316–326,2012Copyright #Taylor &Francis Group,LLC ISSN:0882-7508print =1547-7401online DOI:10.1080/08827508.2011.601478316D o w n l o a d e d b y [M a s u d A b d e l l a t i f ] a t 02:34 22 M a y 2012ferrosilicon known as silicothermic process.The second recovers magnesium chlor-ide from raw material and converts it to metal through molten salt electrolysis.Industrial thermal magnesium processes are based on the silicothermic reduction of calcined dolomite.The major processes for the thermal reduction of magnesium oxide in dolime are the Pidgeon,the Magnetherm,and the Bolzano pro-cess (Aghion and Golub 2006).The first commercial thermal process was the Pidgeon process (Pidgeon and Alexander 1944).The process was invented and developed in Canada by Dr L.M.Pidgeon,in the early 1940s.This batch process is carried out in gas-or coal-fired retorts and consists of the solid-state reaction of calcined dolo-mite (CaO ÁMgO)and ferrosilicon at 13Pa and 1150 C.The magnesium vapor con-denses and forms a solid crystalline ‘‘crown’’at the water-cooled end of the retort.The process is heat-transfer limited,labor intensive,and involves long cycle times.It is used by Timminco at the original Pidgeon plant in Canada,and by Chinese mag-nesium producers.The production rate per retort is only 50kg of magnesium per day.The primary magnesium producing reactions in these thermal processes are between silicon,in the ferrosilicon (75%Si,25%Fe),and the magnesium oxide in the dolime (CaO ÁMgO):2ðCaO ÁMgO Þðs Þþðx Fe ÞSi ðs Þ!2Mg ðs Þþ2ðCaO ÁSiO2Þðs ÞþFe ðs Þð1Þ½D G ¼600:6À0:269T ð K Þ;kJ and ½D H ¼519:3À9:374ln T ð K Þ;kJ Although there are huge amounts of dolomite ore,two ferrosilicon manufacturers,and relatively cheap energy,magnesium is not currently being produced in Iran.The Iranian market conditions favor the Pidgeon process,over the electrolytic pro-cess (Mehrabi 2005).Therefore,it is necessary to technically evaluate the dolomite resources that are available in Iran as a first step towards selecting the most suitable ore that can be used for the production of magnesium in the Pidgeon process.A careful review and sampling from major dolomite deposits in Iran (Mehrabi 2005)shows that the Zefreh dolomite is one of the most suitable dolomite deposits in Iran.It is also located in an area where the infrastructures exist for future development of a magnesium production plant (Mehrabi 2005;Mehrabi and Masoudi 2009).In this study,we have characterized the Zefreh dolomite ore,and investigated the parameters affecting the silicothermic reduction of the Zefreh dolomite,using Semnan ferrosilicon,in the Pidgeon process.RAW MATERIALThe Zefreh dolomite mine is located 80km northeast of the city of Isfahan in Central Iran.The annual dolomite production is 100kt =y from the Permian and Triassic dolomitic units.In this study,samples were collected during two field sea-sons.The petrography of 60samples,for dolomite and calcite,was carried out using a Zeiss Axioplan2polarized light microscope after staining with alizarin red and potassium ferricyanide (Dickson 1965).Twenty-five samples were analyzed by WD-XRF (Wavelength dispersive X-ray fluorescence;Philips Magic-Pro),10sam-ples by quantitative XRD (X-ray diffraction;Philips Expert-Pro)using RietveldEVALUATION OF ZEFREH DOLOMITE 317D o w n l o a d e d b y [M a s u d A b d e l l a t i f ] a t 02:34 22 M a y 2012method,and four samples by DTA (differential thermal analysis)–TGA (thermogra-vimetric Analysis)(Netzsch STA 409PC).The run off mine and a composite sample (prepared from the collected samples)were analyzed by WD-XRF,and due to the similarity and comply with the industry standard,run off mine sample was selected as a representative sample for the calcining and reduction tests.The full analytical results are available from the corresponding author.EXPERIMENTALIn the Pidgeon process,magnesium metal is produced from calcined dolomite under vacuum at high temperatures using ferrosilicon as a reducing agent.In this process,the finely crushed dolomite is feed into kilns where it is calcined and then pulverized in a mill prior to mixing with finely ground ferrosilicon.After weighing and homogenizing,the calcined dolomite and ferrosilicon mixture is made into bri-quettes which are charged in a retort and placed in the reduction furnace.The reduction operation is a batch process releasing magnesium in vapor form,which condenses in the cooled end of the retort outside furnace wall.After removal from the furnace,the magnesium ‘‘crown’’is removed from the sleeves.The experimental assessment of the dolomite was carried out in the Mintek Laboratories in South Africa.The calcining of a representative dolomite sample from Zefreh was carried out in an induction furnace,consisting of a steel housing,alumina insulating bricks,and copper induction coils.A programmable temperature controller was used to adjust the heating rate and to control the temperature at the desired value for a certain period of time.A K-type thermocouple was used to mea-sure the sample temperature and was positioned just above the magnesia crucible that contained the sample.Briquettes of known proportions of ferrosilicon and cal-cined dolomite were prepared using a press machine.Both reactants were milled to À150m m in a conventional steel ball mill and mixed prior to briquetting.The reduction tests were performed on the briquetted mixture using the retort setup shown in Figure 1.The assembly consisted of 316stainless steel tube (100mm ID and 480mm long).The tube (retort)was housed inside an electrically heated fur-nace (silicon carbide elements).The furnace is insulated with alumina bricks,and is provided with a programmable temperature controller.The retort contained a gas outlet which was connected to a vacuum system,consisting of a vacuum pump,pressure transducer,pressure and temperature read-outs,a shut-off valve,and an argon purge line.Two thermocouples were used to measure and control the temperature.The first was placed just outside the retort,while the second was located inside it to measure and record the reaction tempera-ture.The pressure and temperature readings were recorded throughout the test using a data logger.Calcining was carried out for 4hours at 1400 C in order to drive off almost all of the carbon dioxide and moisture,as well as the easily volatilized components.After cooling,the mass loss was measured and samples were taken and analyzed (see Table 1).Calcining of dolomite can be broadly described as follows:ðCaCO 3ÁMgCO 3Þðs ÞþHeat ¼ðCaO ÁMgO Þðs Þþ2CO 2ðg Þð2Þ318 B.MEHRABI ET AL.D o w n l o a d e d b y [M a s u d A b d e l l a t i f ] a t 02:34 22 M a y 2012½D G ¼291:96À0:3313ð K Þ;kJ and ½D H ¼292:14À0:0187T À2Â10À5T 2ð K Þ;kJ The calcining work was intended to prepare sufficient material for the reduction tests and was based on the DTA-TGA data,industrial practice,and Mintek’s experience in this field.Briquetting of Semnan ferrosilicon and Zefreh dolime involved accurately weighing predetermined amounts of each reactant,mixing,and pulverizing to À150m m in a ball mill.Particle size analysis was carried out on the mixture.The bestTable 1.Chemical analyses of Zefreh dolomite,dolime,and Semnan ferrosilicon (%)Dolomite MgO CaO Al 2O 3SiO 2Fe 2O 3MnO Ni LOI 20.6031.100.090.410.530.06<0.0546.90Dolime MgO CaO Al 2O 3SiO 2Fe 2O 3MnO Ni LOI 37.7558.280.240.831.160.09<0.05<0.1Ferrosilicon Mg Ca ÃAl Si Fe Mn Ni ÃC 0.03<201.2672.1019.110.11650.08Ãppm.Figure 1The setup used for experimental work in the Mintek Laboratory,South Africa.EVALUATION OF ZEFREH DOLOMITE 319D o w n l o a d e d b y [M a s u d A b d e l l a t i f ] a t 02:34 22 M a y 2012size distribution (for the Test 2repeat onward)using standard sieve of þ75,À75þ53,À53þ38,and À38m m was measured as 48.59%,12.98%,12.37%,and 26.17%respectively.The mixture was then pressed to produce briquettes of 30mm in diameter and 15mm thick using a hydraulic press (pressure was set at 20MPa in Tests 1and 2and 30MPa in subsequent tests).The final mass of the briquettes was then recorded prior to being placed inside the retort.After sealing,the retort was pressure-tested by applying vacuum of 500–700Pa,switching off the vacuum pump,and monitoring the pressure readings.A leakage rate of 0.5cm 3=min,or less,was considered to be acceptable to initiate the reduction test.Once the leak test was successful,the retort was heated to 700 C over a 2-hour period,followed by a degassing period of 2hours (at 700 C)in order to drive off any residual moisture and =or carbon dioxide that may have been present in the reactants.For a short period,the retort pressure would increase slowly by 100–300Pa before dropping back to 500–700Pa.The temperature was then increased to 1150 C over a 2-hour period and the reduction reaction allowed continuing for about 8hours.The pressure tended to increase slightly when the temperature approached 1100 C–1150 C.This pressure change was similar to that observed during the degassing period and lasted for only a few minutes.The furnace power was then switched off (as well the vacuum pump),and the system was brought up to just above atmospheric pressure by introducing argon into the retort.Finally,the facility was allowed to cool down to near room temperature before opening the retort and collecting the products.Both the mass of briquette residue (slag)and magnesium crown were measured,and clean samples were taken for chemical analysis.In most tests,a small amount of powdery material formed on the side walls of the retort (less than 1gram),particularly near the flange area.This material was recovered,weighed,and analyzed separately.In addition to the commissioning test,three tests were carried out in order to evaluate the effect of the FeSi =dolime ratio,grinding rate,and briquette making conditions on the extraction of magnesium.RESULT AND DISCUSSIONSThe chemical composition of Semnan ferrosilicon and Zefreh dolomite sample is shown in Table 1.The ferrosilicon contains about 72%silicon and 19%iron,whereas the normal composition of the material used for magnesium production contains 75%Si,with the balance being mostly Fe.The products of each reduction test consisted of three distinct phases:magnesium crown that condensed mainly on the side at the end of the retort,as this is the coldest section of the setup;a white deposit that tended to stick to the side walls of the retort (about 1g per test);and the reacted briquettes.Each product was carefully removed from the retort,weighed,and analyzed.The briquette residues produced in Tests 1and 2(as well as the commissioning Test)were relatively high in MgO (see Table 2).This is believed to be related,in part,to the milling and mixing of the reactants and the pressing of the briquettes in relation to the particle size and the FeSi =dolime contact surface area.The surface contact area between FeSi and dolime particles has a major impact on the reaction320 B.MEHRABI ET AL.D o w n l o a d e d b y [M a s u d A b d e l l a t i f ] a t 02:34 22 M a y 2012(Morsi et al.2002),as magnesium reduction under the experimental conditions used is a solid–solid reaction.When the contact area is relatively small (large particles and =or inadequate mixing and pressing),the reduction reaction does not proceed to completion.In addition,the initial contact area can easily be blocked by the reac-tion products,leading to a lower magnesium extraction efficiency and hence a higher MgO in the resulting briquette residue.Further milling and mixing (Test 2repeat onward)and briquetting at higher pressures resulted in a lower MgO content in the briquette residue,as can be seen in the results of Test 2and Test 2repeat (2R).These two tests used 19.8%FeSi ing Mintek’s Pyrosym software (Jones 1987)and experimental data,the FeSi addition was increased to about 21%(Test 3and 3R)leading to a further reduction of the MgO content in the briquette residue which reached about 7.6%.Notice that in Table 2,both iron and silicon in the briquette residue are expressed as oxides.This is not entirely true,as most of the iron and unreacted silicon tend to form a FeSi alloy (residual ferrosilicon).Other metals (Mn,Ni,etc.)tend to concentrate in this FeSi product.Chemical analysis of samples taken from the condensed magnesium (referred to as crown)suggests that impurity levels are not significantly different from those contained in crude magnesium produced either in the Magnetherm or Mintek ther-mal magnesium processes (Abdellatif 2006a,2006b).In Tests 1and 2where dolime was used with a FeSi addition of 18.0%and 19.8%,the purest crown product was produced (see Table 2).In subsequent tests,the crown tended to contain higher levels of calcium,and in some cases silicon.In these tests,the ferrosilicon addition was 21%of the dolime mass,an addition level that could have contributed to increased volatilization of calcium and silicon (mostly as SiO).Table 2.Chemical analyses of briquette residue and crown magnesiumBriquette residueMgOCaO Al 2O 3SiO 2FeO MnO TiO 2Cr 2O 3Co Ni Comm.17.8547.45 2.4526.207.700.200.11 1.09<0.050.24Test 112.2049.500.8735.10 6.860.380.180.31<0.05<0.05Test 213.0051.540.6529.80 6.550.070.05<0.01<0.05<0.05Test 2R 9.5052.220.9627.647.130.130.08<0.01<0.05<0.05Test 37.8152.800.9435.559.380.110.03<0.01<0.05<0.05Test 3R7.6354.041.0237.297.650.140.10<0.01<0.05<0.05Magnesium crownMgCa Al Si Fe Mn Ti Cr Co Ni Comm.75.740.740.250.240.560.020.03<0.050.020.12Test 197.150.770.07<0.20<0.500.030.02<0.050.020.04Test 21000.26<0.05<0.20<0.50<0.010.02<0.050.010.03Test 2R 97.50 2.72<0.05<0.20<0.50<0.01<0.01<0.05<0.010.03Test 395.23 2.390.300.66<0.500.07<0.01<0.05<0.010.03Test 3R97.052.23<0.05<0.20<0.50<0.01<0.01<0.05<0.010.03Note :Comm.,commissioning test;R,repeat test.EVALUATION OF ZEFREH DOLOMITE321D o w n l o a d e d b y [M a s u d A b d e l l a t i f ] a t 02:34 22 M a y 2012Nickel analysis may have been affected by the use of a nickel grease to ease the tightening and loosening of the bolts of the flange.Iron,nickel,manganese,and chromium could have entered into the metal from the retort itself where scaling was observed in certain tests.Magnesium extraction was calculated based on the mass of briquette residue and its magnesium content (see Table 3)and is defined as follows:(Magnesium in feed ÀMagnesium in briquette residue Þ=Magnesium in feed Âð100%Þ;where:Magnesium in feed ¼Dolime mass ÂMg analysis in dolimeMagnesium in briquette residue ¼Briquette residue mass ÂMg analysis in Briquette residue massThe magnesium extraction efficiency was relatively low in Tests 1and 2,where the ferrosilicon addition was 18%and 19.8%,respectively.This may be due to various factors including the particle size of the milled reactants and the briquetting con-ditions.Therefore,for the subsequent tests,the dolime and ferrosilicon were milled further and briquetted at higher pressure in order to increase the surface contact between ferrosilicon and the dolime particles.Doing so resulted in higher extractionTable 3.Magnesium extraction and condensation efficiencyTest no.Extraction (%)Condensation efficiency (%)Comm.50.78NA Test 167.1260.3Test 265.0199.3Test 2R 75.02101.3Test 379.4797.0Test 3R79.7597.5Note :Comm.,commissioning test;R,repeat test.Table 4.Overall mass balanceMaterials in (g)Materials out (g)Test no.Dolime FeSi Total Mg crown B.res.MgO Total Acc.(%)Comm.100.0018.00118.007.75126.300.00134.05113.60Test 1167.8830.62198.5016.36174.700.83191.8996.67Test 2167.0033.00200.0024.92169.620.43194.9797.49Test 2R 156.9831.02188.0028.22157.800.67186.6999.30Test 3166.5835.82202.4030.70165.300.00196.0096.84Test 3R168.4335.37208.8032.50168.700.62201.8296.66Note :Comm.,commissioning test;R,repeat test;Acc.,accountability.322 B.MEHRABI ET AL.D o w n l o a d e d b y [M a s u d A b d e l l a t i f ] a t 02:34 22 M a y 2012Figure 2XRD pattern of Zefreh dolomite,Mg crown,white precipitated material inside the flange,and briquette residue(slag).Figure 3BSE image of Mg crown and the chemical composition of the white area (EDAX).The Mg content is from Mg crown and probably the Fe and Si are impurities.In some of the point analysis,Ca was recorded.EVALUATION OF ZEFREH DOLOMITE 323D o w n l o a d e d b y [M a s u d A b d e l l a t i f ] a t 02:34 22 M a y 2012efficiency in the repetition of Test 2.Increasing the ferrosilicon content to 21%resulted in a magnesium extraction efficiency of about 80%in Test 3.The last column in Table 3is an estimate of the magnesium condensation efficiency.Although the data are very preliminary as no attempt was made to opti-mize the condensation efficiency,the calculated values are very high for all the tests.It should be noted that the measured flange temperature where most of the conden-sation took place was about 300 C.Magnesium condensation was defined as follows:Mg condensation ¼Magnesium in the crown =Magnesium extracted Â100%Figure 4SEM image of crown magnesium showing a small deposition of a calcium compound.The image has been acquired few weeks after reduction,and it seems that calcium has been blossomed.324 B.MEHRABI ET AL.D o w n l o a d e d b y [M a s u d A b d e l l a t i f ] a t 02:34 22 M a y 2012As previously stated,increased ferrosilicon,addition relative to dolime,may lead to higher levels of impurities in the condensed magnesium.Therefore,a compro-mise between magnesium extraction and metal refining requirement is usually sought based upon economic considerations.As shown in Table 4,the overall mass recovery was consistently high and ran-ged from about 97.0%to 99.3%during the tests,except for the commissioning run.The samples of crown magnesium,briquette residue,and the white deposit on the side of retort were analyzed by XRD (see Figure 2).The crown magnesium was studied by Cameca SX-100EPMA (see Figure 3)and TESCAN SEM (see Figure 4).The area covered by crystalline magnesium is pure,while in poorly crystalline areas,there are traces of calcium,silica,and iron.On the surface of magnesium crystals,there were small deposits of calcium compound which was also found inside the crystals (back scattered electron (BSE)image on polished sample).CONCLUSIONChemical and mineralogical analysis of the Zefreh dolomite sample indicates that it is suitable for magnesium production in a thermal process (such as Pidgeon).Test works using the Zefreh calcined dolomite and its reduction by Semnan ferrosi-licon in the Pidgeon process were carried out in 500Pa,1150 C,for 10–12hours,and yield a suitable magnesium metal in terms of magnesium extraction and crude mag-nesium metal quality.In spite of the low Si content of the Semnan ferrosilicon (72%)compared with the industry standard (75%)and with no addition of fluorite as a catalyst,magnesium extraction efficiency was determined as 79.75%.Changing the ratio of Zefreh calcined dolomite to the FeSi addition allowed the extraction efficiency to be optimized.Reducing the particle size to À150m m,increasing ferrosilicon content to 21%,and using a briquetting pressure of 30MPa resulted in a magnesium extraction of 79.75%and condensation efficiency of 97.5%,although it does produce higher levels of impurities in the crown magnesium.The temperature of cool end of retort,during condensation,was set about 300 C which resulted in a very high condensation efficiency for all the tests.The levels of major impurities in the magnesium crown were similar to those in the crude metal production.ACKNOWLEDGMENTSAuthors wish to thank Dr.David Banks,School of Earth and Environment,Leeds University,for reading and improving the manuscript.We would like to thank Prof.S.K.Kawatra and five anonymous reviewers whose constructive comments significantly improved the manuscript.This work was financially supported by Iranian Ministry of Industries and Mines (Makta grant)and Tehran Tarbiat Moallem University research vice-chancellor.REFERENCESAbdellatif,M.,2006a,‘‘Pilot plant demonstration of the Mintek Thermal MagnesiumProcess.’’In Proceedings of the International Symposium on Magnesium Technology inEVALUATION OF ZEFREH DOLOMITE 325D o w n l o a d e d b y [M a s u d A b d e l l a t i f ] a t 02:34 22 M a y 2012the Global Age ,(M.O.Pekguleryuz and L.W.F.Mackenzie,Eds.),Conference of the Metallurgist,Montreal,Quebec,Canada,Met.Soc.of CIMM,pp.67–80.Abdellatif,M.,2006b,‘‘Refining testwork on crude magnesium produced in the Mintek Thermal Magnesium Process.’’In Southern African Pyrometallurgy 2006International Conference ,(R.T.Jones,Ed.)Johannesburg,South Africa:SAIMM,pp.343–355.Aghion,E.and Golub,G.,2006,‘‘Production technologies of magnesium.’’In Magnesium Technology:Metallurgy,Design,Applications ,(H. E.Friedrich and B.L.Mordike,Eds.),Heidelberg:Springer,pp.29–62.Cherubini,F.,Raugei,M.,and Ulgiati,S.,2008,‘‘LCA of magnesium production;techno-logical overview and worldwide estimation of environmental burdens.’’Resources,Conservation and Recycling ,52,pp.1093–1100.Dickson,J.A.D.,1965,‘‘A modified technique for carbonates in thin section.’’Nature ,205(4971),p.587.Ding,W.and Zang,J.,2001,‘‘The Pidgeon process in China,’’3rd Annual Australasian Magnesium Conference,Sydney,Australia,pp.7.Habashi,F.,1997,Handbook of Extractive Metallurgy,Vol.2,Weinheim:Wiley.Jones,R.T.,1987,‘‘Computer Simulation of Pyrometallurgical Processes.’’In Proceedings of the Twentieth International Symposium on the Application of Mathematics and Compu-ters in the Minerals Industries,Vol.2.Metallurgy,Johannesburg,SAIMM,p.265.Mehrabi, B.,2005,‘‘The Most Suitable Technology for Magnesium Production from Mg-bearing Minerals in Iran’’(in Persian).University of Industries and Mines,Makta1324-MIM grant,Final Report.Mehrabi,B.and Masoudi,F.,2009,‘‘Magnesium Metal Production Using Lloyd Pidgeon Process’’(in Persian).University of Industries and Mines,Makta 17238-MIM grant,Final Report.Morsi,I.M.,El-Barawy,K.A.,Morsi,M.B.,and Abdel-Gawad,S.R.,2002,‘‘Silicothermic reduction of dolomite ore under inert atmosphere.’’Canadian Metallurgical Quarterly ,41(1),pp.15–28.Pidgeon,L.M.and Alexander,W.A.,1944,‘‘Thermal production of magnesium–-pilot plant studies on the retort ferrosilicon process.’’Transactions AIME ,159,pp.315–352.Zang,J.and Ding,W.,2001,‘‘The Pidgeon process in China and its future,’’Magnesium Technology,Warrendale,PA:Minerals,Metals,and Materials Society,pp.7–10.326 B.MEHRABI ET AL.D o w n l o a d e d b y [M a s u d A b d e l l a t i f ] a t 02:34 22 M a y 2012。

The subsequent developments of a case are crucial in the legal process,as they determine the final outcome and the justice served.Here is a detailed account of how a case might progress after its initial stages:1.Investigation:After a case is filed,the first step is an indepth investigation.This involves gathering evidence,interviewing witnesses,and understanding the circumstances surrounding the incident.The police or a detective agency is typically responsible for this.2.PreTrial Proceedings:Once the investigation is complete,the case moves to pretrial proceedings.This phase includes bail hearings,preliminary hearings,and the exchange of evidence between the prosecution and defense.It is a critical time for both parties to prepare their cases and negotiate possible plea deals.3.Discovery:During this phase,both the prosecution and defense have the opportunity to request and receive evidence from one another.This process helps ensure a fair trial by allowing both sides to understand the case against them and prepare their arguments accordingly.4.Plea Bargaining:In many cases,before the trial begins,the defendant may choose to negotiate a plea bargain with the prosecution.This is an agreement where the defendant pleads guilty to a lesser charge or to the original charge in exchange for a lighter sentence.5.Trial:If a plea bargain is not reached,the case proceeds to trial.During the trial,both sides present their arguments,call witnesses,and present evidence to support their case. The judge ensures that the trial is conducted according to the law,and the jury if applicable is responsible for determining the guilt or innocence of the defendant.6.Deliberation and Verdict:After all the evidence has been presented,the jury retires to deliberate.They review the evidence and arguments presented during the trial and decide whether the defendant is guilty or not guilty.In some cases,a unanimous decision is required,while in others,a majority verdict may suffice.7.Sentencing:If the defendant is found guilty,the next phase is sentencing.The judge considers various factors,including the nature of the crime,the defendants criminal history,and any mitigating or aggravating circumstances,before determining the appropriate punishment.8.Appeal:Following the verdict and sentencing,either the prosecution or the defense may choose to appeal the decision to a higher court.This can be based on variousgrounds,such as procedural errors,legal misinterpretations,or new evidence that was not available during the trial.9.PostConviction Relief:If the appeal is unsuccessful,the defendant may seek postconviction relief through various means,such as filing a motion for a new trial, seeking clemency,or pursuing habeas corpus.10.Execution of Sentence:Once all legal avenues have been exhausted,the defendant begins serving their sentence,which could include imprisonment,probation,fines,or community service.Throughout these stages,the legal system aims to balance the rights of the defendant with the need to uphold justice and protect society.Each case is unique,and the specific details of the subsequent developments will vary based on the nature of the crime,the jurisdiction,and the individuals involved.。

·16·2018 3Neutrino NatureNeutrinoless double-beta decay(0νββ)experiment is a powerful tool for determining the nature of neutrino: Majorana or Dirac fermion.This is one of the few most foundermental physics questions beyond the successful Standard Model.The0νββdecay has been pursed ever since it is suggested in1930s.The limit on the effective Majorana mass has been pushed down to∼100meV in recent years,corresponding to a decay half-time of∼1026 a.The primary goal of the Neutrino Nature group at QMRC is to establish a next generation high sensitivity experiment in order to search for the0νββand to identify the dominant decay mechanism.We will propose an experiment:No neutrino Double-beta Experiment(NνDEx)to be located in the underground laboratory CJPL in Jingping,China.The NνDEx project aims to take advantage of the recent development of the Topmetal sensors and the gainless TPC to have a high energy resolution,together with the choice of large Q-value isotope82Se with Q=2.995MeV to achieve high sensitivity.The projected limit on the effective Majorana mass for one tonne,five-year data is about5∼14MeV,corresponding to a half-time of1028a.The low cosmic background environment in CPJL makes it the ideal place for this experiment.In addition,the group will work on high precision calculations of various observables such as decay half-lives and electron spectra,etc.through a collaborative effort from the nuclear theorists and particle physicists.The ultimate goal is tofind the new physics behind the decay and answer the question on the origin of neutrino mass. References[1]T.D.Lee,G.C.Wick,Phys.Rev.D,9a(1974)2291.[2]P.Braun-Munzinger,J.Stachel,Nature,448,(2007)302.[3]J.Adams,et al.,[STAR Collaboration],Nucl.Phys.A757,(2005)102.[4]M.Gyulassy,L.McLerran,Nucl.Phys.A,750(2005)30.[5]Y.Aoki,G.Endrodi,Z.Fodor,et al.,Nature,443,(2006)675.[6]S.Gupta,X.Luo,B.Monhanty,et al.,Science,332,(2011)1525.[7]Z.G.Xiao,Eur.Phys.J.A,50(2014)37.[8]eRHIC Homepage:[/WWW/publish/abhay/HomeofEIC].[9]JLab EIC Homepage:[https:///wiki/index.php/MainPage].[10]EIC-White Paper:“Electron-Ion Collider:Next QCD Frontier”,arXiv:1212.1701.[11]INT-Write-Up:“Gluons and the Quark Sea at High Energies:Distributions,Report on the Physics and Design Concepts forMachine and Detector”,arXiv:1206.2913.Polarization,Tomography”,arXiv:1108.1713.[12]J.L.Abelleira Fernandez,“A Large Hadron Electron Collider at CERN:[13]Y.T.Liang,“A Conceptual Design for EicC Detector”,(2019).[14]JLab E12-16-007:[https:///abs/1609.00676].[15]For reference see[https:///experiment/DVCS/].2-2Cosmic-ray Charge Measurement by DAMPE PlasticScintillator Detector∗Zhang Yapeng and Ding MengPrecisely measuring the energy spectra of cosmic-rays is vital to constrain the cosmic-ray production mechanism[1] and their propagation in the stellar medium[2].DArk Matter Particle Explorer(DAMPE)[3]is a high-resolution multi-purpose device for detecting cosmic-rays including electrons,γ-rays,protons and heavy ions in an energy range of a few GeV to100TeV.DAMPE has been launched on December17th,2015and operates on a sun-synchronous orbit at the altitude of500km.DAMPE consists of four sub-detectors:a Plastic Scintillator Detector(PSD),a Silicon-Tungsten Tracker(STK),a Bismuth Germanate Oxid Calorimeter(BGO)and a NeUtron Detector(NUD).The PSD is designed to fulfill two major tasks:(a)to measure the charge of incident high-energy particles with the charge number Z from1to26;(b)to serve as a veto detector for discriminatingγ-rays from charged particles.The on-orbit temperature variation of the PSD is verified to be less than1℃,which is a crucial factor for maintaining a stable performance of the PSD.After the calibration steps of pedestal,dynode ratio,response to minimum ionizing particles,light attenuation function and energy reconstruction,the charge of incident cosmic-ray particle can be obtained by comparing its energy deposition to the one of minimum-ionizing protons.The detailed calibration of PSD is presented in Ref.[4].The reconstructed charge of incid.ent particles(Q L/R/Crec)could be extracted by following expression:Q L/R/Crec =√E L/R/CA L/R/C(x)×sD,(1)2018·17·where,E L/R/C is the energy of left/right/combined side of a PSD bar(E C=√E L E R),s is the path length of theparticle inside the volume of the PSD bar,D=10mm is the thickness of the PSD bar,A L/R/C(x)is the corresponding light attenuation function and x is the hit position given by a selected track.Due to the quenching effect,the energy loss of high Z particles in matter is smaller than the one given by the Bethe equation.In order to correct the above mentioned effects,the mean of visible peaks in reconstructed charge spectra(Q L/R/C distribution)of each PSD bar are obtained by a series of Gaussianfits.Based on the obtained peak position and nominal charge number pairs,a third-order spline function(SP3)for each charge measurement (left/right/combined side)of a PSD bar is constructed,respectively.For each reconstructed charge(see Eq.(1)), a quenching-effect corrected charge can be obtained from the corresponding third-order spline function.For the reconstructed charge above Fe i.e.Q rec>Q Ferec,a linear function is used to correct the quenching effect,which is fitted from the pairs of peak position and nominal charge number with Q rec>10.Fig.1shows a typical data pairs of the obtained peak position and charge number(open circles),the constructed third-order spline function and thefitted linear function are depicted by the solid line and dotted line,respectively.The dash-dotted line is the bisector(ordinate=abscissa)as a reference.After applying this correction,the charge spectra reconstructed from different PSD bars are aligned on a bisector(Q rec=Z).Fig.2shows a charge spectrum reconstructed by the PSD of DAMPE,the major cosmic-ray elements from H-Ni can be identified clearly.Fig.1(color online)Peak positions obtained from a re-constructed charge spectrum versus charge numbers.Fig.2(color online)Charge spectrum reconstructed by the PSD of DAMPE.References[1]L.Drury,Astropart.Phys,39-40(2012)52.[2]I.Grenier.Ann.Rev.Astron.Astrophys,53(2015)199.[3]J.Astropart.Phys,95(2017)6.[4]M.Ding.Research in Astronomy and Astrophysics,19(2019)47.∗Foundation item:National Natural Science Foundation of China(11673047,U1738127)2-3Upsilon Production at an Electron-Ion Collider in China∗Cao Xu and Yang ZhiVector meson photo-and electro-production on nucleon at high energies are important reactions to study the gluon component within nucleon.One of the main concerns of the planned Electron-Ion Collider in China(EicC) is near-threshold Upsilon(Υ(1S))production,where another two topics are critically relevant.First,it is an ideal machine to search for exotic nucleon states with hidden bottom(P b),whose lowest mass in many theoretical models is expected to be a bit higher than Upsilon production threshold.Second,it is a promising platform to measure directly trace anomaly term in the proton mass decomposition,resulting into a deep exploration of the origin of the nucleon mass.In order to study the near-threshold Upsilon production,we need to know its cross section as a premise.The。

交叉询问制度合理性反思—Jill Hunter教授《颠覆美好的认知：反思证据法的失败》*述评戴晓东*（中国政法大学，北京 100088 ）【摘要】交叉询问制度有其固有缺陷，盲目引入并不能真正促进庭审中心主义发挥实效。

所以，我们需要对交叉询问制度进行必要的反思，这也是Jill Hunter教授《颠覆美好的认知：反思证据法的失败》一文的中心思想。

通过对该文的介绍和评述，可以从中获取对我国交叉询问制度构建的有益启示。

【关键词】交叉询问；固有缺陷；反思；启示【中图分类号】D915.13【文献标识码】A【文章编号】1674-1226（2017）01-0030-13Examining the reasonableness of the cross-examination system: reviewing professor jill hunter’s “battlinga good story: cross-examining the failure of the law of evidence”. Dai Xiaodong. China University of PoliticalScience and Law, Beijing 100088.【Abstract】The system of cross-examination has its inherent defects,blindly transplanting whichinto China legal system cannot really promote the substantial effects of the trial centralism. Therefore, we need to reconsiderthe cross-examination system, which has been discussed in Professor Jill Hunter’s "Battling a Good Story: Cross-examining the Failure of the Law of Evidence”. Byreviewing this article, we could obtain many useful insights onhow to construct a cross-examination system in China.【Key Words】 Cross-examination, Inherent defects, Rethinking, Enlightenment2016年6月27日，中央全面深化改革领导小组第25次会议审议通过了《关于推进以审判为中心的刑事诉讼制度改革的意见》，要求“规范法庭调查程序，确保诉讼证据出示在法庭、案件事*该文是Jill Hunter教授在2004年7月诺丁汉大学举办的“证据教学学术”研讨会上的参会文章，得到了英美澳等国证据法学者的普遍好评。