简介：摘要：新型材料的引入可以提供更好的导电性能、更低的损耗和更轻的重量，新型材料还可以提供更好的抗腐蚀性能和耐候性，从而延长天线的使用寿命。结构设计的改进也可以显著影响短波发射天线的性能，优化天线的尺寸和形状，以适应不同的工作频率和传输距离，也可以提高天线的性能。新型材料和结构设计对于短波发射天线的性能具有重要影响，通过引入新材料和优化结构设计，可以提高天线的导电性能、轻量化、抗腐蚀性能等，从而改善短波发射机的性能。本文将对LF2001A型发射机的性能进行研究，探讨新型材料和结构设计对其性能的影响，并提出相应的改进措施。

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简介：Therehavebeenreportsformanyyearsthattheionosphereisverysensitivetoseismiceffects,andthedetectionofionosphericperturbationsassociatedwithearthquakes(EQs)attractsalotofattentionasaverypromisingcandidateforshort-termEQprediction.InthisreviewwepresentapossibleuseofVLF/LF(verylowfrequency(3-30kHz)/lowfrequency(30-300kHz))radiosoundingofseismo-ionosphericperturbations.Inordertoavoidtheoverlappingwithmyownpreviousreviews,wefirstshowsomepioneeringresultsfortheKobeEQandwetrytopresentthelatestresultsincludingthestatisticalevidenceonthecorrelationbetweentheVLF/LFpropagationanomalies(ionosphericperturbations)andEQs(especiallywithlargemagnitudeandwithshallowdepth),medium-distance(6-8Mm)propagationanomalies,thefluctuationspectraofsubionosphericVLF/LFdata(theeffectofatmosphericgravitywaves,theeffectofEarth’stides,etc.),andthemechanismoflithosphere-atmosphere-ionospherecoupling.Finally,weindicatethepresentsituationofthiskindofVLF/LFactivitiesgoingonindifferentpartsoftheglobeandwesuggesttheimportanceofinternationalcollaborationinthisseismo-electromagneticstudy.

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简介：IllustrationAllthedatainthiscatalogarechosenfromthe(PreliminarySeismologicalReportofChineseSeismicStations((Itsabbreviationis(MonthlyReport().ThecatalogincludestheeventsofM(4.7inandnearChinaandM(6allovertheworld.The(MonthlyReport(ismonthlycompiledbytheNinthSectionofInstituteofGeophysics,CSB.Theorigintimesofearthquakesinthecatalogadoptcoordinateduniversaltime(UTC)inaccordancewithinternationalconvention.Thelocationofeveryepicenterisexpressedbyitslatitudeandlongitude,atthesametimebythecorrespondinggeographicalregionproposedbyFlinnandEngdahl.Theregionalnamesareonlyforreferencesanddonotimplyanypoliticalsignificance.Thenumberofstationsusedandstandarddeviationarealsogiveninordertoillustratetheprecisionoflocation.

简介：Morethanahalfofstrongearthquakesintheworldarelocatedinshallowdepthatthesubductingplateboundaryinsqueezedzones.Owingtothedifferenceinspeedbetweenthemovingseaplates,thestrainenergyisaccumulatedandreleasedcyclicallyinsqueezedzones.Severalmethodsweredevelopedtoanalyzethemedium-andshort-termpotentialofmainshocks.Thesemethodscanbeclassifiedinto(1)lessdatasystemsusingthetheoryofgreymodelforearthquakeprediction,(2)quasi-periodicsystemsusingearthquakeactivityanalysis,(3)systemsofgroupedactivityusingorderanalysis,and(4)nonlinearsystemsusingbackpropagation(BP)ofneuralnetworkforpredictionanalysis.Basedupontheseanalyticmethods,riskmapsforthepredictionofstrongearthquakescanbedrawnusingtherecordsofstrongearthquakesinTaiwanforthepast100years.Theseriskmapsinclude(1)aseismicriskmap,(2)alossriskmap,(3)ahazarddegreemap,and(4)alossdegreemap.Theseriskmapsmakeitpossibletodoamedium-termpredictionofmainshocksonthe10-yearscale.

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简介：TheSimplifiedSimpleBiospheremodel(SSiB)isvalidatedinoff-linesimulationsagainstfieldmeasurementsinthesummerof2001fromtheChinaHeavyRainfallExperimentandStudy(CHeRES)overagrasslandsitelocatedinthelowerreachesoftheYangtzeRiver.Wheninitializedanddrivenbytheobservedatmosphericforcing,themodelreproducedtheobservedsurfaceheatfluxesandsurfaceskintemperaturerealistically.Themodelwasalsoabletowellsimulatethevariationofsoilwatercontent.Thesensitivityexperimentsfoundthattheleafreflectancewasthemostsignificantparameterinimprovingtheestimationofsurfacealbedoduringbothwetanddryperiods.Thisstudysuggeststhatthemodeliscapableofsimulatingthephysicalprocessesandofassessingtheimpactofbiophysicalparametersthatrelatetoland-atmosphereinteractionsovertheeasternAsianmonsoonregions,whichiscrucialformesoscaleatmosphericmodels.

简介：OnOctober27,2001,alargeearthquakewithMs6.0,namedtheYongshengearthquake,occurredalongtheJinshajiangsegmentofChenghaifaultinYongshengCounty,YunnanProvince.ItisthelargesteventtooccuralongtheChenghaifaultinthelast200years.Theseismo-geologicalsurveyshowsthattheseismogenicfault,whichistheJinshajiangsegmentofChenghalfault,takesleft-lateralstrike-slipasitsdominantmovementpattern.Accordingtodifferencesinverticalmotion,motiontime,landformsandscales,theChenhalfaultcanbedividedintoeightsegments.TheJinshajiangsegmenthasaverticaldislocationrateof0.4mm/a,farlowerthanthemeanrateoftheChenghaifault,about2.0mm/a.It'sdeducedthatthetwosidesofJinshajiangsegment'stuck'tightlyandhinderedthestrike-slipoftheChenghaifault.ThestrongearthquakedistributionbeforethiseventshowsthattheJinshajiangsegmentwasintheseismicgap.TheChenghaifault,asaboundaryoftectonicsub-blocks,makestheNorthwestYunnanblockandtheMiddleYunnanblockmoveclockwise,andtheirmarginsmoveoppositelyalongtheChenghalfault.InthemotionprocessoftheChenghaifault,structuralhindranceandtheseismicgapofstrongearthquakesarepropitioustotheconcentrationandaccumulationofstructurestress.Asaresult,theYongshengMs6.0earthquakeoccurred.TheSujiazhuang-ShangangfusegmentissimilartotheJinshajiangsegmentwithalowverticalmotionrateof0.3mm/aandintheseismicgap.Soit'spostulatedthatthesegmentmaybecomeanewstructurehindrance,andtheYongshengMs6.0earthquakemaytriggertheoccurrenceoffuturelargeearthquakesalongthissegment.

简介：21世纪的第一个十年，陨石学与天体化学研究在中国迎来了一个前所未有的发展时期。在南极格罗夫山地区共开展了5次科学考察，收集到超过1万块陨石，提供了珍贵的研究样品；嫦娥工程的立项和一期工程的成功实施，是陨石学与天体化学发展的重大机遇，也是挑战；高精度原位微区分析平台建设的完成，则为地外物质样品的分析提供了关键的技术保证。更为重要的是，通过大量南极陨石的分类工作，培养和锻炼了陨石学研究的青年人才。在此基础上，通过对各化学群陨石的研究，取得了许多重要的成果，包括陨石中前太阳颗粒的发现和研究、陨石中的灭绝核素、太阳星云在不同条件下的凝聚过程、月球陨石和火星陨石的岩石学成因与同位素定年、陨石的冲击变质与高压矿物、以及中国第一个陨石坑的证实等。

简介：Inthispaperchangesinfocalmechanisms,parametersofwavespectra,andstressdropsfortheMS=5.0foreshockandMS=6.0mainshockinFebruary2001inYajiangCounty,Sichuan,andseismicityinepicentralregionarestudied.ComparisonoffocalmechanismsfortheYajiangearthquakeswithdistributionpatternsofaftershocks,thenodalplaneI,strikinginthedirectionofNEN,oftheYajiangM=5.0eventischosenasthefaultingplane;thenodalplaneII,strikinginthedirectionofWNW,oftheM=6.0eventasthefaultingplane.Thestrikesofthetwofaultingplanesarenearlyperpendiculartoeachother.ThelevelofstressdropsintheepicentralregionbeforetheoccurrenceoftheM=6.0earthquakeincreases,whichisconsistentwithincreaseofseismicityintheepicentralregion.TheratedecayoftheYajiangearthquakesequence,changesinwavespectraforforeshocksandaftershocks,andfocalmechanismsarecomplex.

简介：NewObservationsonphosphatizedSpheroidalFossilsinSinianDoushantuoanPhosphoritesinWeng'an,GuizhouProvinceInrecentyearsmuchattentionhasbeenpaidtophosphatizedspheroidalfossilsfoundintheSinianDoushantuoanphosphoritesinweng'an,GuizhouProvince.Disputeshavebeenlongexistedabouttheirphylogeneticaffinity.Basedonsomenewdiscoveriesandthepresentknowledge,someresearchersinterpretsomeofthephosphatizedspheroidalfossilsasanimalembryos,whereasothersholodtheutterlyidifferentviewthattheypaper,basedonnewdataofsomespheriodalfossilsindiscussedandreinterpreted.Itisobviousthatthephosphatizedspheroidalfossilassemblagefoundinweng'anconsistsofcyanobacteria,benthicmelticellularalgae,planktonicacritarchsandotherfossilswithuncertainassignments,andprovideanexceptionallywell-preservedphosphatizedLagerstatten.

简介：1气候概况今年秋季全区气温偏高,降水中西部地区偏多,东部区偏少;初霜冻中西部地区偏晚,东部大部地区偏早,全区未出现严重霜冻灾害,日照充足,秋末局部地区出现降雪、降温天气,大风偏少.

简介：摘要：本文研究了基于数学模型的LF-RH冶炼过程中C成分控制精度的预测与优化方法。通过建立LF和RH设备的数学模型，并结合实际工艺数据进行模拟和优化，提出了一种改进的控制策略，以提高C成分的控制精度和冶炼效果。

简介：2001年6月11～13日，三明市出现了一场连续性暴雨到大暴雨天气过程，强降水集中在我市的西北部，建宁、将乐、宁化、清流、明溪等县出现了暴雨或大暴雨，大暴雨中心在清流，6月13日雨量达195．9毫米，宁化次之，该日雨量为154．9毫米（见表1）。这次连续性暴雨过程的特点是：持续时间长、强度大、灾情重。

简介：利用MICAPS系统资料和台站网络系统资料对2001年6月23日宁波地区4个测站出现暴雨和大暴雨过程的环境形势、物理量场、单站要素、卫星云图及多普勒雷达回波图进行了天气学诊断分析,揭示其主要环境条件特征,研究其变化规律,结合多年业务实践,利用相似的气候背景条件和物理量、要素图象特征,试图为大暴雨前0～24小时的预报提供背景依据.

简介：TheYajiangearthquakesequencein2001,withthemajoreventsofMs5.1onFeb.14andofMs6.0onFeb.23,aresignificanteventsintheSichuanregionduringthelast13years.Eighty-eightearthquakesinthesequencewithatleast5distinctonsetparametersforeachrecordedbytheSichuanSeismicNetworkintheperiodofJan.1throughJune30,2001werechosenforthisstudy.TheeventsarerelocatedandthefocalmechanismisderivedfromP-waveonsetsfor13eventswithrelativelylargermagnitudes.Thefocaldepthofallearthquakesfallbetweenarangeof2kmto16km,withdominantdistributionbetween9kmto11km.Theforeshocks,theMs5.1earthquakeandtheMs6.0earthquakeandtheiraftershocksarealllocatedclosetotheZihefaultandthedominantepicentraldistributionisinNWdirection,identicaltothatofthefault.ThefracturesurfaceofthefocalmechanismisdeterminedinaccordancetothemasstransferorientationintherecentearthdeformationfieldintheYajiangregion.ThePaxesoftheprincipalcompressivestressinfocalmechanismsolutionsofthe13eventsshowbiggerverticalcomponents,andthehorizontalprojectiontrendingSE.Theearthquakesareofleft-lateral,strike-slipnormal,andnormalstrike-sliptypes.TherupturesurfaceofmostearthquakesstrikeNW-SE,dippingSW.Basedontheaboveinformation,weconcludethattheZihefaultthatcrossestheearthquakearea,strikingNWanddippingSW,istheseismogenicfaultfortheYajiangearthquakesequence.

简介：Usingthe78focalmechanismsolutionsoftheforeshocks,mainshockandaftershocksoftheearthquakesequencefortheYao'anearthquake,thecharacteristicsofthefocalfaultsandstressfieldfortheearthquakesequenceareanalyzed.TheresultsshowthatthemainruptureplaneoftheYao'anearthquakesequenceisatectonicfaultwithN50°Wstrikeandsteepdipandallthemainshock,theforeshocksandthevastmajorityofaftershocksoccurredonthemainruptureplane.AtectonicfracturewithNNE-NEstrikealsoparticipatedindevelopmentprocessofthesequencedominatedbyprincipalcompressionalstresswithnearlyhorizontalorientationSSEisconsistentwiththeregionaltectonicstressfield.Inthesequencedevelopment,thestressfieldinthefocalregionwascomplexwithmultiaximuthsandmulti-actionmodelsandthefocalruptureshowedcomplexfeatureswithmulti-directionsandmulti-patterns.