简介:摘要:电缆是煤矿电力传输,安全生产的关键设备之一,担负着安全生产的重要任务。煤矿井下环境恶劣,在长期运行过程中,电缆绝缘水平逐渐降低,可能导致漏电、接地、短路等故障,造成供电系统停电等。长此以往,多数电缆一般都是定期检修,不仅需要大量的人力和财力,而且不能及时发现电缆绝缘水平的下降。开发矿用高压动力电缆绝缘故障监测系统,实时监测电缆在运行过程中的绝缘性能。提取预警信息,有效预警电缆故障。
简介:【摘要】针对2017-2019年在注水管理过程中对注水场站管理粗放、地质配注完成率低、在线配注合格率低的问题,为树立、宣传正面典型,起到示范带动全区注水管理工作在2020年全面提升,对岭19增在注水管理中好的做法在全区进行推广。
简介:Theeffectofhydrogenpassivationonmulticrystallinesilicon(mc-Si)usedforsolarcellsisdescribed,andthemechanismofhydrogendiffusionandpassivationisalsoinvestigated.Then,thehydrogenpassivationprocessesappliedinindustriesandresearchlaboratoriesareintroduced.Finallytheexistingproblemsandtheprospectsofhydrogenpassivationarereviewed.
简介:Thisstudytestedfivemethodswidelyusedinestimatingthecompletemagnitudes(MC)ofearthquakecatalogs.Usingcatalogsofobservedearthquakeproperties,wetesttheperformanceofthesefivealgorithmsunderseveralchallengingconditions,suchassmallvolumeofeventsandspatial-temporalheterogeneity,inordertoseewhetherthealgorithmsarestableandinagreementwithknowndata.Wefindthatthemaximumcurvaturemethod(MAXC)hasperfectstability,butwillsignificantlyunderestimateMCunlessheterogeneityisabsent.MCestimatedbytheb-valuestabilitymethod(MBS)requiresmanyeventstoreachastableresult.Resultsfromthegoodnessoffitmethod(GFT)wereunstablewhenheterogeneityloweredthefitnesslevel.Theentiremagnituderangemethod(EMR)isrelativelystableinmostconditions,andcanreflectthechangeinMCwhenheterogeneityexists,butwhentheincompletepartoftheearthquakecatalogisdismissed,thismethodfails.Themedian-basedanalysisofthesegmentslopemethod(MBASS)cantoleratesmallsamplesize,butisincapableofreflectingthemissingdegreeofsmalleventsinaftershocksequences.InconditionswhereMCchangesrapidly,suchasinaftershocksequences,observingthetimesequencedirectlycangiveapreciseestimationofthecompletesub-catalog,butonlywhenthenumberofeventsavailableforstudyislargeenoughcantheMAXC,GFT,andMBSmethodsgiveasimilarlyreliableestimation.
简介:TotesttheantigenicactivityofMprotein(Mcprotein)intheinnermembraneofSARS-CoV,SARS-CoVMcprotein'sbaseslocatinginsidethemembranewerecloned,theHis-fusionproteinwasexpressedinE.coliandanalyzedforitsantigenicactivity.Amongthose7clinicallydiagnosedpatients'sera,therewere5positiveand2negativeinreactionwithHis-fusionprotein.Allofthe20healthypersons'seraandrabbitanti-OC43and229EwereofnegativereactionwithHis-fusionprotein.TheanimalsimmunizedwithHis-fusionproteinhaveproducedmulti-clonalantibody.TheHis-fusionproteincouldspeciallyreactwithclinicallydiagnosedSARSpatients'seraandtheanimalsimmunizedwithHis-fusionproteincouldproducespecificallymulti-clonalantibody,butitcouldnotreactwiththeseraofhealthypersonsandtherabbitanti-OC43and229E.
简介:代数课本中指出:“在a>0时,|x|>a(?)x<-a或x>a;|x|0”。其实,这一等价性在a≤0时也同样成立。现证明如下:①当a=0吋,i|x|>a即|x|>0的解集显然是:x<0或x>0即x<-a或x>a。
简介:本文介绍了下一代移动通信系统中关键技术——正交频分复用(OFDM),它具有良好的抗多径干扰性能和高频谱利用率。然后给出多载波调制和CDMA结合的MC-CDMA系统,此系统可以支持高数据传输率和高用户容量。接着简述了可以充分利用空间资源,提高无线信道容量和信道可靠性的MIMO技术,并给出结合MIMO和MC-CDMA即MIMO-MC—CDMA系统模型,最后简要介绍了此系统中所涉及的同步及信道估计技术。