简介：Thetitlecomplex[NH_3CH_2CH(NH_2)CH_3]_2[M(Ⅵ)O_2(OC_6H_4O)_2](M=Mo_(0.6)W_(0.4))wassynthesizedviaasimplesolution-phasechemicalroute.ThedeterminationofsinglecrystalX-raydiffractionrevealedthatthetitlecompoundiscrystallizedinamonoclinicsystemwithP2(1)/nspacegroup,a=1.0913(10)nm,b=1.0442(10)nm,c=1.8842(19)nm,α=90°,β=96.530(17)°,γ=90°,Z=4,andV=2.133(4)nm3.Themononuclearanionicunit[M(Ⅵ)O2(OC6H4O)2]2-displayschiralpseudo-octahedral[MO_6]coordinationgeometryandislinkedbychiralcationsviahydrogenbondandπ…πstackinginteraction.Thetransmissionelectronmicroscopyimagesshowthatthetitlecomplexiscomprisedofnano-particleswithdiametersrangingfrom20to50nm.TheNMRstudyshowsthe1Hdownfieldchemicalshiftsof[NH_3CHaHbCH(NH_2)CH_3]+cationsinthetitlecomplexwhenitismixedwithadenosine-triphosphate(ATP),andthechemicalshiftdifferencebetweenHaandHbisincreasedgreatly,andmostofthecatecholateligandsdissociatefromthecentralmetalatoms.TheDNAcleavageactivityexperimentrevealsthatDNAcleavagepromotedbythetitlecomplexislowerthanthatbyNa_2MoO_4whichpossessesantitumorpro-perty,buthigherthanthatbyNa_2WO_4.

简介：

简介：首先通过讨论具有可选服务和无等待空间的M/G/1排队模型的主算子生成的C0-半群的本质增长界指出0是该主算子的一级极点,然后运用残数定理证明该模型的时间依赖解指数收敛于其稳态解.

简介：采用密度泛函方法(B3LYP)优化了MX2(AsH3)2[M=Pd;X=Cl(1),Br(2),I(3)和M=Pt;X=Cl(4),Br(5),I(6)]的基态结构,得到的几何参数与实验结果符合.以基态几何为基础,将TD-DFT方法用于计算标题配合物的电子吸收光谱.研究结果表明,金属的dx2-y2与配体所组成的反键轨道为LUMO轨道,从而该类配合物具有d-d跃迁属性的吸收带;在多数跃迁过程中,配体也有较大的贡献.

简介：

简介：

简介：借助密度泛函理论，用B3LYP和BP86方法，对一系列潜在的新型高能密度材料分子H2N5MN5H2（M=Be，Mg，Ca，Zn，和Cd）进行了理论预测研究．结果表明，这些材料分子都非常稳定，不容易分解，其中H2N5MN5H2最稳定．金属离子的配位作用对化合物的稳定起了重要作用．配体H2N5也因从金属M获得一个电子变成H2N^-离子而变得更稳定．

简介：合成了三价态过渡金属取代的钨硅杂多配合物αＳｉＷ１１Ｍｘ－（Ｍ＝ＭｎⅢ、ＦｅⅢ、ＣｏⅢ）的Ｋ（或Ｃｓ）盐，通过元素分析、红外、紫外、可见光谱、循环伏安等手段进行了表征．研究了配合物的热稳定性、水溶液中的酸碱稳定性、催化活性以及磁性，常温和变温（８２Ｋ～２７２Ｋ）磁化率数据表明配合物具有顺磁性特征．

简介：Wehavedemonstratedahigh-average-power,high-repetition-rateopticalterahertz（THz）sourcebasedondifferencefrequencygeneration（DFG）intheGaSecrystalbyusinganear-degenerate2μmintracavityKTPopticalparametricoscillatorasthepumpsource.Thepowerofthe2μmdual-wavelengthlaserwasupto12.33Wwithcontinuoustuningrangesof1988.0–2196.2nm/2278.4–2065.6nmfortwowaves.DifferentGaSecystallengthshavebeenexperimentallyinvestigatedfortheDFGTHzsourceinordertooptimizetheTHzoutputpower,whichwasingoodagreementwiththetheoreticalanalysis.Basedonan8mmlongGaSecrystal,theTHzwavewascontinuouslytunedfrom0.21to3THz.ThemaximumTHzaveragepowerof1.66μWwasobtainedatrepetitionrateof10kHzunder1.48THz.Thesinglepulseenergyamountedto166pJandtheconversionefficiencyfrom2μmlasertoTHzoutputwas1.68×10-6.Thesignal-to-noiseratioofthedetectedTHzvoltagewas23dB.TheacceptanceangleofDFGintheGaSecrystalwasmeasuredtobe0.16°.

简介：

简介：该规划的目的是重新研究物理教育的内容和结构，这是由于在三个方面有了重大的发展：①过去的三十年里，物理知识爆炸性地增长；③认知心理学的研究，对学习进程有了新的认识，③计算机技术及其功能不断提高。

简介：

简介：提出了一种求解离子晶体等价格点的单粒子离子Dirac方程方法，确定离子晶体的点电荷电量。利用阴阳离子上分配的价电子数之比，给出了计算离子晶体化学键性质的关单式计算了MX（M=Li、Na、K、Rb、X=F、Cl、Br、I）系列晶体点电产电量值和化学键性质，得到了比较好的结果

简介：ZnOfilmscontainingErandGenanocrystals（nc-Ge）weresynthesizedandtheirphotoluminescence（PL）propertieswerestudied.Visibleandnear-infraredPLintensitiesarefoundtobegreatlyincreasedinnc-Ge-containingfilm.Er-related1.54μmemissionhasbeeninvestigatedunderseveralexcitationconditionsupondifferentkindsofGe,ErcodopedZnOthinfilms.1.54μmPLenhancementaccompaniedbytheappearanceofnc-Geimpliesasignificantcorrelationbetweennc-GeandPLemissionofEr3+.Theincreasedintensityof1.54μminGe:Er:ZnOfilmisconsideredtocomefromthejointeffectofthelocalpotentialdistortionaroundEr3+andthepossibleenergytransferfromnc-GetoEr3+.

简介：Anumberofnaphthalenedonorcompoundsthatpossessanadamantanaminebindingmoietyandan(OCH2CH2)n(nn1,2,3,4,6,8)spacerweresynthesized.Thefluorescencequenchingbetweenthesedonorsubstratesandmono-6-O-p-nitrobenzoyl-β-cyclodextrin(pNBCD)andmono-6-O-m-nitrobenzoyl-β-cyclodextrin(mNBCD)wasstudiedindetail.Itwasfoundthatveryefficientfluorescencequenchingcouldoccurinthesesupramolecularsystems.Thisquenchingwasattributedtothephotoinducedelectrontransferinsidethesupramolecularassemblybetweenthenaphthalenedonorsandcyclodextrinacceptors.DetailedStern-VolmerconstantsweremeasuredandtheywerepartitionedintodynamicStern-Volmerquenchingconstantsandstaticbindingconstants.Itwasdemonstratedthatthebindingconstantsbetweenallthenaphthalenecompoundsandcyclodextrinsarethesameastheypossessthesamebindingsite,i.e.,adamantanamine.

简介：用离子交换法将具有Keggin结构TBA4H3PW7Mo3Cu2O38（H2O）2（M=Fe2＋，Co2＋，Cu2＋，Ni2＋和Mn2＋）嵌入到Zn2A1黏土中，得到层状化合物LDH-PW7Mo3Cu2O38（H2O）2（M=Fe2＋，Co2＋，Cu2＋，Ni2＋和Mn2＋），并用XRD，IR，uV对其进行了表征．结果表明：杂多阴离子进入黏土后，仍保留了其Keggin结构．利用合成的层状化合物为催化剂，以顺丁烯二酸与HzO。的环氧化反应为模型反应考察其催化活性，结果表明：层状化合物在环氧化反应中显示优良的催化性能．