简介：TheemergenceofZhangHeng’sseismoscopehasaprofoundhistoricalbackground.ThispaperintendstoexploretheformationandmaterialbasisofZhangHeng’sscientificthought.Itappearsthatthesimpleintentionof"observingvisionsanddistinguishinggoodfortuneormisfortune"washismotivationtodeveloptheseismoscope.Tracingitshistoricalbackground,theauthorsproposedinthispaperthatthedevelopmentofthisseismoscopestartedaround128A.D.,andbasedonperceptualknowledge,twoideasaboutearthquakescameintobeing,i.e.,earthquakelocationcouldbejudgedaccordingtotheinstrumentshakingdirection,andtheearthquakeandearthsplitwereessentiallydifferent.Intheinstrumentmanufacture,ZhangHengadvocatedaprincipleof"makingutensilstoimitatecosmos".Bythisprinciple,thefollowingthreeproblemswerereadilysolved:theseismoscopeimitatedtheresponseofthesuspensionsystemtoearthquakes(i.e.naturalseismoscope).Technically,thetriggermechanismofthelatchwasusedforreference,anditrecordedthephysicalevidenceofearthquakeoccurrencebyaningeniouswayofaballdroppingfromadragon’smouth.Thesolutionofthesethreekeyproblemsleadtotheemergenceoftheseismoscopein132A.D.andthesuccessfuldetectionofanearthquakein134A.D.Hisinventiondeepenedhumanity’sknowledgeofnaturallaws,andpromotedthedevelopmentofscienceandtechnologyinthattimeandlater.

简介：HistoricaldataregardingZhangHeng'sseismoscopeisnotsingularproof.Actually,thefourearliesthistoricaldocuments,i.e.,ContinuationofHistoriographyofHanDynasty,HistoriographyoftheLaterHan,BookoftheLaterHanandDingRecordallhaverelevantrecordsofitsstructure,size,principle,responsetoearthquakeandactualapplications.Thesefiveaspectsaresupportedbyarchaeologicalresearch,unearthedculturalrelics,historicalearthquakesandmodernseismologicalstudy.Thesehistoricalmaterialscontainagreatdealofspecificinformationaboutthisancientseismoscope.Inconclusion,theauthenticityandreliabilityofZhangHeng'sseismoscopeareverified.

简介：基于其体积小、重量轻、一致性好等特点,单片微波集成电路的低噪声放大器在射电天文中有着重要作用。本文采用稳懋公司150nm和100nm赝高电子迁移率晶体管(pseudomorphichighelectronmobilitytransistor,pHEMT)工艺设计了两款低噪声放大器电路,成功流片,并进行比较。两款放大器的工作频率范围均为8-20GHz,增益约为23~28dB,噪声温度低于150K,输入输出回波损耗大于10dB。

简介：EstimationofThomsen＇sanisotropicparametersisveryimportantforaccuratetime-to-depthconversionanddepthmigrationdataprocessing.Comparedwithothermethods,itismucheasierandmorereliabletoestimateanisotropicparametersthatarerequiredforsurfaceseismicdepthimagingfromverticalseismicprofile（VSP）data,becausethefirstarrivalsofVSPdatacanbepickedwithmuchhigheraccuracy.Inthisstudy,wedevelopedamethodforestimatingThomsen＇sP-waveanisotropicparametersinVTImediausingthefirstarrivalsfromwalkawayVSPdata.Modelfirst-arrivaltraveltimesarecalculatedonthebasisofthenear-offsetnormalmoveoutcorrectionvelocityinVTImediaandraytracingusingThomsen＇sP-wavevelocityapproximation.Then,theanisotropicparameters0andearedeterminedbyminimizingthedifferencebetweenthecalculatedandobservedtraveltimesforthenearandfaroffsets.Numericalforwardmodeling,usingtheproposedmethodindicatesthaterrorsbetweentheestimatedandmeasuredanisotropicparametersaresmall.Usingfielddatafromaneight-azimuthwalkawayVSPinTarimBasin,weestimatedtheparameters0andeandbuiltananisotropicdepth-velocitymodelforprestackdepthmigrationprocessingofsurface3Dseismicdata.Theresultsshowimprovementinimagingthecarbonatereservoirsandminimizingthedeptherrorsofthegeologicaltargets.

简介：摘要本文简要分析我国起重机检验中存在的一些问题，并从钢丝绳、吊钩、焊接环形链、滑轮与护罩以及制动器等方面浅谈如何提高起重机检测质量与效率。

简介：摘要随着微机的硬件，软件的跨越式发展，"3s"技术作为一项新技术手段，结合抽样技术、数学方法、计算机网络技术、通讯技术和数据库技术，使森林资源管理与信息技术紧密相结合，在现代化林业建设中建立森林资源动态监测体系、森林资产价值评估系统、森林生态环境监测与管理系统等方面，发挥重要作用，使林业走上现代化高速发展的道路。

简介：Thepost-earthquakerapidaccurateassessmentofmacroinfluenceofseismicgroundmotionisofsignificanceforearthquakeemergencyrelief,post-earthquakereconstructionandscientificresearch.TheseismicintensitydistributionmapreleasedbytheLushanearthquakefieldteamoftheChinaEarthquakeAdministration(CEA)fivedaysafterthestrongearthquake(M7.0)occurredinLushanCountyofSichuanYa’anCityat8:02onApril20,2013providesascientificbasisforemergencyrelief,economiclossassessmentandpost-earthquakereconstruction.Inthispaper,themeansforblindestimationofmacroscopicintensity,fieldestimationofmacrointensity,andreviewofintensity,aswellascorrespondingproblemsarediscussedindetail,andtheintensitydistributioncharacteristicsoftheLushan'4.20'M7.0earthquakeanditsinfluentialfactorsareanalyzed,providingareferenceforfutureseismicintensityassessments.

简介：Ingeneral,earthquakecyclerelatedtoearthquakefaultingcouldincludefourmajorprocesseswhichcouldbedescribedby(1)faultlocking,(2)self-accelerationornucleation(possibleforeshocks),(3)coseismicslip,and(4)post-stressrelaxationandafterslip.Asuddenstaticstresschange/perturbationinthesurroundingcrustcanadvance/delaythefaultinstabilityorfailuretimeandmodifyearthquakerates.Basedonasimpleone-dimensionalspring-sliderblockmodelwiththecombinationofrate-and-statedependentfrictionrelation,inthisstudy,wehaveapproximatelyderivedthesimpleanalyticalsolutionsofclockadvance/delayoffaultfailurescausedbyasuddenstaticCoulombstresschangeappliedinthedifferenttemporalevolutionperiodsduringanearthquakefaulting.Theresultshavebeenusedinthephysics-basedexplanationofdelayedcharacteristicearthquakeinParkfieldregion,California,inwhichthenextcharacteristicearthquakeofM6.0after1966occurredin2004insteadofaround1988accordingtoitscharacteristicreturnperiodof22years.Atthesametime,theanalyticalsolutionsalsoindicatethatthetimeadvance/delayinCoulombstresschangederivedbythedislocationmodelhasacertainlimitationandfundamentalflaw.Furthermore,wediscussedtheessentialdifferencebetweenrate-andstate-variableconstitutive(R–S)modelandCoulombstressmodelusedcommonlyincurrentearthquaketriggeringstudy,anddemonstratedthat,infact,theCoulombstressmodelcouldbeinvolvedintheR–Smodel.Theresults,wehaveobtainedinthisstudy,couldbeusedinthedevelopmentoftime-dependentfaultinteractionmodelandtheprobabilitycalculationrelatedtothetime-dependentandrenewalearthquakepredictionmodel.

简介：摘要水轮机是水电站中最主要的动力设备之一，它关系到水电站工程投资、安全运行、动能指标及经济效益等重大问题，正确地进行水轮机选择是水电站设计中的主要任务之一。影响水电站水机选型设计的因素众多，本文通过对水机选型设计原则的分析介绍了水电站水机选型的一般内容，并分别以大小水电站为例探讨了水机选型的一些要点问题。

简介：摘要土压平衡盾构是集机、电、液、气一体的复杂设备，在使用过程中所发生的故障也是多样的，土压平衡盾构机故障发生后如不及时处理就会影响工程的质量和安全。本文重点对三种土压平衡盾构机典型故障的处理进行了研究。

简介：摘要富源信德矿区上部地层结构松散、破碎、钻孔坍塌严重。而且存在少量石灰岩，灰岩裂隙大，漏水严重。而设计的钻孔深度大。给施工带来很大困难，通过采取多级钻孔结构，并在钻进参数，冲洗液、钻头扩孔器上的合理应用，解决了施工难题，顺利完成了1204米深ZK502#钻孔。

简介：摘要由于桥式起重机在各个行业中的应用越来越多，范围越来越广，所以其检修工作也应该越来越被人所重视，以保证其正常稳定运行，减少不必要的安全风险。本文结合多年来的工作经验，对于桥式起重机常见的一些检修项目以及流程和方法进行了总结，希望能为相关单位和人员提供一定的参考。

简介：摘要材料试验机在开发新材料和材料质量控制领域的应用越来越广泛，作为大型精密仪器，对它的控制精确性、智能性及人机交互便利性都提出了很高的要求。然而，目前的材料试验机使用中容易出现一些测量误差，必须采取措施确保控制系统的精确性。本文分析了试验机产生误差的规律，并重点探讨了材料试验机误差问题的几个方面及控制措施。

简介：摘要盾构始发时，需要安装一个为盾构机提供反作用力的构件，即反力架。在盾构始发施工时，反力架的支撑作用位置一般有两种一种是采用直撑直接作用于后方端墙，另一种是采用斜撑作用于底板。本文首先分析了盾构机反力架结构的设计原则，然后结合具体工程案例详细阐述了盾构机反力架结构的设计及应用要点。

简介：TheresistivityexperimentalmeasurementsofcoresamplesdrilledfromlowpermeabilityreservoirsofOrdosBasin,NorthwestChina,illustratethatthecementationfactorsarenotagminate,butvaryfrom1.335to1.749.Thisleadstoachallengefortheestimationofwaterandhydrocarbonsaturation.BasedontheanalysisofPurcellequationandassumptionthatrockresistivityisdeterminedbytheparallelconnectionofnumerouscapillaryresistances,atheoreticalexpressionofcementationfactorintermsofporosityandpermeabilityisestablished.Then,cementationfactorcanbecalculatediftheparametersofporosityandpermeabilityaredetermined.Inthefieldapplication,porositycanbeeasilyobtainedbyconventionallogs.However,itisatoughchallengetoestimatepermeabilityduetothestrongheterogeneityoflowpermeabilityreservoirs.Thus,theSchlumbergerDollResearch(SDR)modelderivedfromNMRlogshasbeenproposedtoestimatepermeability.BasedontheanalysisofthetheoreticalexpressionsofcementationfactorandSDRmodel,anovelcementationfactorpredictionmodel,whichisrelevanttoporosityandlogarithmicmeanofNMRT2spectrum(T2lm),isderived.TheadvantageofthismodelisthatalltheinputinformationcanbeacquiredfromNMRlogsaccurately.Inordertoconfirmthecredibilityofthenovelmodel,theresistivityandcorrespondinglaboratoryNMRmeasurementsof27coresamplesareconducted.Thecredibilityofthemodelisconfirmedbycomparingthepredictedcementationfactorswiththecoreanalyzedresults.Theabsoluteerrorsforallcoresamplesarelowerthan0.071.Oncethismodelisextendedtofieldapplication,theaccuracyofwaterandhydrocarbonsaturationestimationwillbesignificantlyimproved.

简介：摘要沥青拌合机的生产能力决定沥青拌合料的供应情况，是保证沥青路面施工工期的可控技术措施，本文简要地说明沥青拌合机拌合能力的控制要点。

简介：利用2000年和2010年遥感影像，分析了四川省隆昌县10a间土地利用/覆被变化情况，并进行驱动力分析。研究表明，2000~2010年，耕地（包括水田和旱地）、水域、未利用地面积减少，林地、城镇、交通用地面积增加。分析表明，隆昌县土地利用/覆被变化的驱动力主要有人口因素、社会经济因素、城市化因素、政策导向，各因素间相互影响和制约。

简介：摘要随着铁路建设的发展，铁路架桥机的使用日益频繁，虽然国家为特种设备的安全使用制定了相应的法律法规，使用单位也专门制定了完善的安全管理制度，但近几年来，由于各种各样的原因，架桥机脱轨、倾覆事故时有发生，往往造成机毁人亡的重大后果，需要引起人们足够的重视，本文以中铁七局郑徐铁路客运专线08标段箱梁架设为例，简述架桥机在施工过程中的安全管理措施，希望可以提供一些有价值的参考意见。

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简介：摘要本文介绍了DPF800碟式分离机的结构及其工作原理，并重点介绍了对于喷嘴及碟片组的设计改进，提高碟式分离机的装配效率和分离性能。