简介：在介绍B．VANROOTSELAAR的解方程组x′=Ax的一种新方法的基础上，对矩阵F（0）求法作了补充，对照以往通常的解法，分析了它的优越性．文章用完全开放性的Maple语言程序在计算机上实现了这种方法的应用，并通过生动的例子说明了同样是借助计算机强大的计算功能，新的解法在速度上要提高上百倍，更有实用价值．

简介：拉制金属表被合拢与11%变硬工作。这些随后被使用，抵抗焊接构造X类型格子捆绑有0.17的核心亲戚密度的三明治面板。三明治面板在单轴的压缩被测试，为比较，有限元素的方法被采用模仿测量压缩压力紧张曲线。山峰压缩力量比金字塔形的核心三明治的高是32%。变硬工作的X类型格子结构的提高的机械性质主要与弯曲并且工作变硬的低度从直神气的贡献发源，而非二维的蹒跚的节点。

简介：由一种计算分圆多项式系数的简捷算法给出和证明了分圆多项式的系数绝对值不大于1的若干条件，并对分圆多项式的系数的一些性质进行了研究。

简介：

简介：

简介：Veryrecently,BelleannouncedtheirobservationofΥ(5S)!bJ!(J=0;1;2),indicatingthattheΥ(5S)!bJ!decaysalsohavelargedecaywidths,i.e.,themeasuredbranchratiosofΥ(5S)!bJ!are<3:410??3,(1:640:23+0:30??0:22)10??3,and(0:570:220:07)10??3withJ=0;1;2,respectively[1].ItshouldbenoticedthateventhoughthetreelevelcontributionstoΥ(5S)!bJ!(J=0;1;2)shouldbestronglysuppressedduetotheOkubo-Zweig-Iizuka(OZI)rule,suchlargedecaywidthsareobserved,whichagaininspiresourinterestinunderstandingsuchquantities.Inthiswork,weproposethatthecontributionfromthehadronicloopshouldbeconsideredinstudyingΥ(5S)!bJ!.

简介：Inthisarticle,wetaketheX(5568)asthediquark-antidiquarktypetetraquarkstatewiththespin-parityJ~P=0~+,constructthescalar-diquark-scalar-antidiquarktypecurrent,carryouttheoperatorproductexpansionuptothevacuumcondensatesofdimension-10,andstudythemassandpoleresidueindetailswiththeQCDsumrules.WeobtainthevalueM_X=(5.57±0.12)GeV,whichisconsistentwiththeexperimentaldata.ThepresentpredictionfavorsassigningtheX(5568)tobethescalartetraquarkstate.

简介：在脉冲X射线测量中,当出射X射线粒子总数低于108时,通过闪烁体成像测量角分布的方法难以获得结果。提出了一种将准直孔阵列、快时间响应闪烁体和多路延时光纤相结合的电流型测量方法,通过记录不同角度的瞬时脉冲波形,能够实现ns以下小焦斑快脉冲X射线角分布的测量。基于该方法研制的测量系统在亚ns重复频率快脉冲硬X射线源上进行了实验验证,获得了距源20cm处的角分布数据。

简介：

简介：Anewseriesofliquidcrystalscomprisingeightheterocyclicisoflavoneesters,7-alkanoyloxy-3-[4’-(3-methylbutyloxyphenyl)]-4H-1-benzopyran-4-onesexhibitingenantiotropicnematic(N)andsmecticC(SmC)phasesweresynthesizedandinvestigated.Themesomorphicpropertiesofallderivativeswereinvestigatedbymeansofdifferentialcalorimetryandpolarizedopticalmicroscopy.WideangleX-raydiffractiontechniquewasemployedtoinvestigatethemolecularpackingassociatedwiththeintermolecularinteractionaswellasthecorrelationbetweenthethermalbehaviourofthesecompoundswiththeiranisotropypropertieswithinamesophase.

简介：

简介：ThispaperconstructstheinteractionpotentialoftheSH(X2Π)radicalbyusingthecoupled-clustersinglesdoubles-approximate-triplestheorycombiningthecorrelation-consistentquintuplebasissetaugmentedwiththediffusefunctions,aug-cc-pV5Z,inthevalencerange.Employingthepotential,itaccuratelydeterminesthespectroscopicparameters.ThepresentDe,Re,ωe,ωeχe,αeandBevaluesareof3.7767eV,0.13424nm,2699.846cm?1,47.7055cm-1,0.2639cm-1and9.4414cm-1,respectively,whichareinexcellentagreementwiththoseobtainedfromthemeasurements.Atotalof19vibrationalstateshasbeenfoundwhenJ=0bysolvingtheradialSchrdingerequationofnuclearmotion.Thecompletevibrationallevels,classicalturningpoints,initialrotationandcentrifugaldistortionconstantswhenJ=0arereportedforthefirsttime,whichareingoodaccordwiththeexperimentalresults.Thetotalandvariouspartial-wavecrosssectionsarecomputedfortheelasticcollisionsofsulfurandhydrogenintheirgroundstatesatlowtemperatureswhentwoatomsapproacheachotheralongtheSH(X2Π)potentialenergycurve.Overtheimpactenergyrangefrom1.0×10-11to1.0×10-4a.u.,eightshaperesonanceshavebeenfoundinthetotalelasticcrosssections.Foreachshaperesonance,theresonantenergyisaccuratelycalculated.Carefulinvestigationshavepointedoutthattheseresonancesresultfromthel=0,1,2,3,4,6,7,8partial-wavecontributions.

简介：采用X射线衍射技术（XRD）对白云石原矿和不同温度煅烧的白云石原矿进行了物相分析，白云石原矿中主相为CaMg（CO3）2，相对含量约为98．6％，杂质相为SiO2，相对含量约为1．4％。白云石原矿经过300和500℃，煅烧2h未见主相CaMg（CO3）2分解，在750℃煅烧2h，主相CaMg（CO3）2部分分解为碳酸钙和氧化镁，在1000℃煅烧2hCaMg（CO3）2全部分解为氧化镁和氧化钙。

简介：

简介：由用计算机模拟调查的相对论的电子过时的人或物短脉搏激光散布的线性Thomson。它被看那～3的强烈激光脉搏散布3fs在半最大值的完整的宽度，与γ_的一个电子0=10起始的精力，在向后的方向与2.5nm的光子波长产生76attoseconds的超短波的、搏动的放射。一个高度相对论的电子产生的散布放射与更低的相对论的精力电子产生的那相比以它的脉搏宽度和尖分发有优异质量。

简介：TheelectronicpropertiesandtopologicalphasesofThXY(X=Pb,Au,Pt,PdandY=Sb,Bi,Sn)compoundsinthepresenceofspin–orbitcoupling,usingdensityfunctionaltheoryareinvestigated.TheThPtSncompoundisstableintheferromagneticphaseandtheotherThXYcompoundsarestableinnonmagneticphases.Bandstructuresofthesecompoundsintopologicalphases(insulatorormetal)andnormalphaseswithingeneralizedgradientapproximation(GGA)andEngel–Voskogeneralizedgradientapproximation(GGAEV)arecompared.TheThPtSn,ThPtBi,ThPtSb,ThPdBi,andThAuBicompoundshavetopologicalphasesandtheotherThXYcompoundshavenormalphases.Bandinversionstrengthsandtopologicalphasesofthesecompoundsatdifferentpressurearestudied.Itisseenthatthebandinversionstrengthsofthesecompoundsaresensitivetopressureandforeachcompoundasecond-orderpolynomialfittedonthebandinversionstrengths–pressurecurves.

简介：应用波长色散X射线荧光光谱法对中低合金钢、电工钢、高锰钢、不锈钢中锰元素进行测定。采用经验系数法校正元素间的增强-吸收效应和光谱重叠干扰,元素检测限为2.1μg/g,线性相关系数大于0.9998。考察了分析方法的精密度和准确度,元素的测定结果与认定值一致,相对标准偏差小于2%。

简介：

简介：Acompositebeamissymmetricifboththematerialpropertyandsupportaresymmetricwithrespecttothemiddlepoint.Inordertostudythefreevibrationperformanceofthesymmetriccompositebeamswithdifferentcomplexnonsmooth/discontinuousinterfaces,wedevelopanR(x)-orthonormaltheory,whereR(x)isanintegrableflexuralrigidityfunction.TheR(x)-orthonormalbasesinthelinearspaceofboundaryfunctionsareconstructed,ofwhichthesecond-orderderivativesoftheboundaryfunctionsareaskedtobeorthonormalwithrespecttotheweightfunctionR(x).WhenthevibrationmodesofthesymmetriccompositebeamareexpressedintermsoftheR(x)-orthonormalbaseswecanderiveaneigenvalueproblemendowedwithaspecialstructureofthecoefficientmatrixA:=[aij],aij=0ifi+jisodd.Basedonthespecialstructurewecanprovetwonewtheorems,whichindicatethatthecharacteristicequationofAcanbedecomposedintotheproductofthecharacteristicequationsoftwosub-matriceswithdimensionshalflower.Hence,wecansequentiallysolvethenaturalfrequenciesinclosed-formowingtothespecialtyofA.Weusethispowerfulnewtheorytoanalyzethefreevibrationperformanceandthevibrationmodesofsymmetriccompositebeamswiththreedifferentinterfaces.

简介：建立了X射线荧光光谱法测定矿石样品中铀、钍含量的快速分析方法。采用高压粉末制样法,对不同含量的放射性样品的压片压力、粒径、含水率、用量等处理条件到进行单因素实验。在400MPa压力下压制,克服了低压制样的弊端,制备的样片表面光滑、致密,大幅改善了制样重现性,有效地减少了部分基体效应,铀校准曲线的标准偏差从0.053%降到0.0071%,钍校准曲线的标准偏差从0.062%降到0.0057%。经国家一级标准物质验证,表明方法准确、可靠,能满足样品中铀、钍含量日常分析要求。