有机希土金属含硫族化合物的研究进展

本文概述了有机希土(Sc、Y、La-Lu)含硫族元素(S、Se、Te)配位化合物的化学进展,从这类化合物的合成方法、结构特征进行了总结。     

Photocatalytic reduction of dichromate by titanium dioxide supported on hollow glass microbeads

The photocatalytic reduction of dichromate using TiO2/beads as a photocatalyst was studied. The results showed that 3.8 × 10-4 mol/dm3 of dichromate can be completely reduced into Cr3 after illumination for 35 min with a 375 W medium pressure mercury lamp. The effects of factors such as the amount of TiO2/beads , initial concentration of dichromate, initial pH, nitrogen and oxygen atmosphere, and concentration of Fe3 on the photocatalytic reduction of dichromate were investigated. A possible mechamism of the photocatalytic reaction was proposed. After illumination for 200 h, no significant loss of photocatalytic activity of TiO2/beads was observed.     

Efficient Isomerization for Preparing thans-2,2-Dimethyl-3-(2,2-dichloroethenyl) cyclopropanecarbonyl Chloride

2,2-Dimethyl-3-(2,2-dichloroethecyclopropanecarbonylchloride(hereafterreferredtoaspermethricacidchloride)isausefulintermediateforthepreparationofsomesyntheticpyrethroids,suchaspermethrinandcypermethrin.Permethricacidchloridehasageometricalisomericpair,oiLyandtrans,owingtoitscyclopropanering.Itisknownthat,ingeneral,theestersderivedfromtheirans-isomerarelesstoxictomammalsthanthosederivedfromtheets-isomerl--3.Thepermethricacidproducedindustriallyisalwaysinformsofmixturesoftrans-andets-isomers.Ac…     

Synthesis of Asymmetric 4H-1, 3, 2-Benzodioxaphosphorin 2-Sulfides from Intramolecular Cyclization Reaction

Avarietyofbiologicalactivitiesofsome4H-l,3,2-benzodioxaphosphorin2-sulfideshavebeenreported,forexampletheinsecticideSalithionl.Thecyclicphosphonothionateshavebeenpreparedbyintermolecularcondensationofphosphorodichloridothioateswithsalicylalcoholoritsderivativesinthepresenceofabase=,andbyintramolecularcyclizationreactionofthesalicylalasthestartingmaterial3.However,theintramolecularcyclizationreactionofthe2-hydrobenzophenonesandstereochemicalstudieshavenotbeenreported.Wenowdescribeanewsynthesis…     

UNIQUE CONTINUATION ON A HYPERPLANE FOR WAVE EQUATION

51.IntroductionTheuniquecontinuationisthat,ifasolutionofapartialdifferentialequationvanishesinanopenset,thenitmustvanishontheconnectedcomponentwhichcontainsthisopenset.Itiswellunderstoodforellipticoperatorsofthesecondorder.In1939,Carleman[2]showedauniquecontinuationtheoremforsystemsofpartialdifferentia1equationsinthetwodimensionalcasewhosecoefficientsarenotanalytic.Thepowerfu1techniquewhichheproposediscal1edaCaJrlemanestimateandhasplayedacentralroleinthedevelopmentofuIilquecontinuationaJrgum…     

含弥散平面两相渗流驱动问题有限元方法的误差分析

研究了平面两相渗流可压缩问题含弥散情形的矩形有限元格式．引进一类插值算子,通过插值函数证明了有限元解的最优误差估计．     

保面积单调扭转映射的非Birkhoff周期轨的存在性 *

主要研究无穷圆柱面上的恰当的保面积单调扭转映射的Birkhoff不稳定性区域内的动力学性质 .运用Aubry-Mather理论的变分方法 ,给出了无穷多的非Birkhoff周期轨的存在性 :若以某无理数ω为旋转数的不变曲线不存在 ,则对固定的充分接近ω的有理数p/q ,存在无穷多的非Birkhoff周期轨 .     

钠原子光电离过程中角分布参数β的计算

运用多体微扰理论方法 ,对开壳层钠原子的内壳层电子的光电离过程2p⁶3s→ 2p⁵ 3skl中分波散射截面和角分布参数进行了计算 .在计算中包括了 2s→ 3p的共振结构 .同时利用多体微扰理论的图式 ,对主要的电子关联相互作用进行了分析 ,并对RPA和BO关联的主要贡献项计算达到了无穷级近似 .计算结果与实验吻合较好 .     

城市规划监察管理信息系统的设计开发

利用数据库技术及网络技术,经过程序设计,动态链接和CAD绘图,城市规划监察管理信息系统可以提供建立、编辑、查询、统计、打印案卷以及系统维护等一系列功能,从而实现了规划监察的办公自动化,可供其他城市参考。     

清代红绿彩瓷器无损分析研究

红绿彩瓷器是我国陶瓷史上一种重要的釉上彩瓷器,分析其彩料的化学组成和物相结构对其烧制工艺的研究有很重要的意义.但由于瓷器表面的不平整和彩料分布的不均匀性,导致其不满足传统的1 mm×10 m m线光源的X射线衍射仪对样品的测试要求.而毛细管聚焦的X射线衍射仪采用点光源的方式照射样品,毛细管X光透镜对Cu-Kα 的能量有...