简介:ToreducetheproductioncostofBi-2223superconductingtapes,Bi-2223/Ag/Nitapeswerefabricatedbythepowder-in-tubeprocess.TheeffectofheattreatmentonthemicrostructureandcriticalcurrentoftheBi-2223/Ag/Nitapeswerestudied.ThephasecompositionsofthesampleswerecharacterizedusingXRD.ThemicrostructurewasobservedusingSEM.ExperimentalresultsindicatethathighertemperatureismoreconducivetotheformationofBi-2223phaseatanatmosphereof8.5%O2.Afterthetwo-steph...
简介:以前,无论是空战、海战,还是陆战,对于实力相当的作战部队来说,武器装备基本势均力敌。可是近海作战就不一样了,火力强大的舰艇吨位一般都比较大,难以到达近海,因此登陆部队只能选择橡皮艇、快艇等小型舰艇靠岸。海上隐蔽环境有限,岸边的防守部队可以在海岸线安置各种武器装备,神出鬼没地发起进攻,而登陆部队却只能依靠运输舰艇的掩护和他们手中的单兵武器反击……在地理优势和武器装备都稍逊一筹的登陆战中,如何确保近海作战的胜利呢?濒海战斗舰、特种快艇、近海支援舰……各种提升近海作战能力的舰艇出现了。其中,作为专门输送特种兵的新概念装备——M80"短剑"高速隐形快艇更是大大提高
简介:Theequilibriumgeometries,relativestabilities,andelectronicpropertiesofMnAgm(M=Na,Li;n+m≤7)aswellaspureAgn,Nan,Lin(n≤7)clustersaresystematicallyinvestigatedbymeansofthedensityfunctionaltheory.Theoptimizedgeometriesrevealthatfor2≤n≤7,therearesignificantsimilaritiesingeometryamongpureAgn,Nan,andLinclusters,andthetransitionsfromplanartothree-dimensionalconfigurationsoccuratn=7,7,and6,respectively.Incontrast,thefirstthree-dimensional(3D)structuresareobservedatn+m=5forbothNanAgmandLinAgmclusters.Whenn+m≥5,astrikingfeatureisthatthetrigonalbipyramidbecomesthemainsubunitofLinAgm.Furthermore,dramaticodd-evenalternativebehavioursareobtainedinthefragmentationenergies,secondorderdifferenceenergies,highestoccupiedandlowestunoccupiedmolecularorbitalenergygaps,andchemicalhardnessforbothpureanddopedclusters.Theanalyticresultsexhibitthatclusterswithanevenelectronicconfiguration(2,4,6)possesstheweakestchemicalreactivityandmoreenhancedstability.
简介:Theintensityandpositionofthecouplingpointsinhighbirefringence(Hi-Bi)fiberscanbedetectedeffectivelyusingdistributedpolarizationcoupling(DPC)detection.Thedetectionsensitivitycandecreaseduetomechanicalvibrationdisturbanceandenvironmentnoise.Thus,amethodbasedonempiricalmodedecompositionisproposedtodetectweakmodecouplingpoints.Thesimulationandexperimentalresultsillustratethattheproposedmethodcansuppressthenoiseeffectivelyandimprovesensitivitysignificantly.Themethodcanidentifycouplingpointsasweakas-60dBembeddedinnoiseautomaticallyandeffectively.ThealgorithmisapplicableforDPC,andtheexperimentalsensitivityisimprovedby10dB.
简介:用构造法研究了路和圈的Mycielski图的点可区别均匀边染色,得到了路和圈的Mycielski图的点可区别均匀边色数,验证了它们满足点可区别均匀边染色猜想(VDEECC).
简介:Thispaperproposesasimplegeometricalraybasedapproachtosolvethestereocorrespondenceproblemforthesingle-lensbi-prismstereovisionsystem.Eachimagecapturedusingthissystemcanbedividedintotwosub-imagesontheleftandrightandthesesub-imagesaregeneratedbytwovirtualcameraswhichareproducedbythebi-prism.Thisstereovisionsystemisequivalenttotheconventionaltwocamerasystemandthetwosub-imagescapturedhavedisparitieswhichcanbeusedtoreconstructbackthe3-dimensional(3D)scene.ThestereocorrespondenceproblemofthissystemwillbesolvedgeometricallybyapplyingtheepipolargeometryconstraintonthegeneratedvirtualcamerasinsteadoftherealCCDcamera.Experimentsareconductedtovalidatetheproposedmethodandtheresultsarecomparedtothecalibrationbasedapproachtoconfirmitsaccuracyandeffectiveness.
简介:为在的盒子象差错为高级放射性的原子废物在一个仓库的近的域里在包围岩石团以内存在一样的大地质的结构,浸透不饱和的无所不在关节的岩石质量的双孔的媒介的一个种联合thermo-hydro-mechanical-migratory模型被建立。在现在的模型,渗出物域和集中域是双的,但是压力域和温度域是集合的单身者,和影响,空格,角度,连续性比率,媒介的组成的关系上的破裂的僵硬能被考虑。同时,有限元素方法的一个二维的节目被开发。拿在是不饱和的一个岩石团定位的一个假想原子浪费仓库是的双孔的媒介一个计算例子,为联合的thermo-hydro-mechanical-migratory的女性的分析在有或没有一个差错,和温度为盒子漏的放射性的核种的条件下面被执行,毛孔压力,流动速度,在岩石团中的核种集中和主要压力被调查。在差错的破裂水流动的结果表演是基本上沿着差错方向,和它的流动速度比在岩石质量中的破裂水的高几乎三个数量级;没有差错,在差错的核种集中也比那高得多,并且核种更快沿着差错移动;而且,差错在岩石团中在毛孔压力和主要压力上有明显的影响。
简介:目的探讨超声检查BI-RADS3级的乳腺不可扪及病变(nonpalpablebreastlesion,NPBL)微创活组织检查(活检)的临床价值。方法回顾性分析2007年1月至2010年12月在本院接受微创活检、超声BI—RADS3级的542例NPBL病例的临床、影像及病理资料,采用卡方检验比较即时活检组(首次超声诊断后3个月之内活检)与随访活检组(随访6个月后活检)发现恶性病变的概率以及两组恶性肿瘤情况的差异。结果全组542例病例,病理确诊恶性病变5例,总体恶性率为0.92%(5/542);50—59岁患者的恶性率为9.68%(3/31),明显高于其他年龄组(20~29岁组0,30~39岁组0.40%,40—49岁组0.57%,60~71岁组0)。即时活检组中恶性病变4例,恶性率为0.91%(4/435);随访活检组中恶性病变1例,恶性率为0.93%(1/107),两者差异无统计学意义(P〉O.05),且两组发现的恶性肿瘤的病灶大小,TNM分期相似。结论超声检查BI—RADS3级的NPBL恶性率低,随访活检是安全的。但对于年龄50岁及以上,超声评估为BI—RADS3级的患者需提高警惕,建议积极进行活检。
简介:ConstantineM.Dafermoshasdoneextensiveresearchattheinterfaceofpartialdifferentialequationsandcontinuumphysics.Heisaworldleaderinnonlinearhyperbolicconservationlaws,whereheintroducedseveralfundamentalmethodsinthesubjectincludingthemethodsofrelativeentropy,generalizedcharacteristics,andwave-fronttracking,aswellastheentropyratecriterionfortheselectionofadmissiblewavefans.Hehasalsomadefundamentalcontributionsonthemathematicaltheoryoftheequationsofthermomechanicsasitpertainsinmodelingandanalysisofmaterialswithmemory,thermoelasticity,andthermoviscoelasticity.Hisworkisdistinctlycharacterizedbyanunderstandingofthefundamentalissuesofcontinuumphysicsandtheirroleindevelopingnewtechniquesofmathematicalanalysis.