用罗丹明B和钼酸铵水相光度法测定痕量锇

本研究在聚乙烯醇存在下，锇与钼酸铵形成络阴离子，继而与罗丹明Ｂ（ＲＢ）形成离子缔合物，该缔合物的摩尔吸光系数ε值为２．６２×１０＾６Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，性范围０－１．２μｇ／２５ｍＬ，检测限为１．３ｎｇ／ｍＬ（ｎ＝８），ＲＳＤ为２．２％（ｎ＝７），缔合物稳定４周，考察了３０多种共存离子的影响，除贵金属和能形成杂多酸的元素外，大多数贱金属不干扰。方法已用于测定某些催化剂和岩矿中的锇，结果     

聚(L-丙交酯)/聚(DL-丙交酯)的结晶性能及相溶性

用共溶液沉淀法制备了聚 (L 丙交酯 ) 聚 (DL 丙交酯 )共混物 (PLLA PDLLA) ,然后用成纤模压法压制成3 2mm的棒材 .用差示扫描量热法研究了共混物的结晶性能和相溶性 .结果表明 ,PLLA组分在共溶液沉淀过程中可生成结晶 ,共混物中PDLLA含量直到 30 %时 ,PLLA组分的结晶熔融温度和结晶度与纯PLLA相同 ,但PDLLA含量为 5 0 %时 ,PLLA组分的结晶熔融温度和结晶度明显下降 .由于加工成型条件的不一致性 ,共混物棒材中的PLLA组分的结晶熔融温度和结晶度呈较大的分散性 .共混物从熔体降温 ,在其后的升温DSC扫描中出现分别相应于PDLLA和PLLA的玻璃化转变 ,表明PDLLA与未结晶的PLLA形成的非晶相是不相溶的     

Optical Isomers of 5-Methyl-1- (1-naphthyl) -1,2,3-triazole in the Crystal Structure

( ± )-5-Methyl-1-( 1-naphthyl )-1,2, 3-triazole by which 5-methyl-1-( 1-naphthyl )-1,2, 3-triazol-4-carboxylic acid was prepared from aromatic amine was reported. The product was investigated with X-ray crystallography. Compound, C13H 11N3, Mr = 209.25, crystallized in the orthorhombic space group Pbca with unit cell parameters a = 1.0373(2) nm, b=1.1691(2) nm, c=1.7579(4) nm, α=90.00°, β=90.00°, γ=90.00°, V=2.1318(7)nm3, Z = 8, Dm = 1. 304 Mg/m3. The optical isomers of 5-methyl-1-(1-naphthyl)-1, 2,3-triazole was investigated in the crystal structure.     

Bi2212相插层化合物的制备及其应用

我们通过气相输运插层化合反应成功制备了高温超导Bi2212相的碘插层化合物IxBi2212,进而制备出碘化汞插层化合物(HgI2)xBi2212.在此基础上,对碘化汞插层化合物(HgI2)xBi2212在丙酮溶液中进行超声剥落,成功制备出了高温超导Bi2212相的纳米粉体.我们对样品进行了表征,并就样品制备技术过程和纳米Bi2212相粉体的应用作了讨论.     

圆弧曲线的有理五次Bézier表示

给出了有理五次Bézier曲线精确表示0<2θ<2π(θ为圆心角)的圆弧及整圆的充要条件,加以了证明并给出了图例..     

低压电子水处理方法的阻垢特性

通过静态和动态两种方法对低压电子阻垢性能进行了实验研究.在静态实验中选用了不同波形的电压信号进行实验,结果表明,阻垢效果最好的为恒压直流,其后依次是三角波、正弦波、方波.恒压直流的动态实验结果表明,增大处理电流,污垢热阻降低,阻垢率增大.低压电子阻垢方法通过电化学反应使成垢离子减少以产生阻垢效果.     

Scheme for Generalized Quantum State Sharing of a Single-Qubit State in Cavity QED

An experimentally feasible scheme for generalized quantum state sharing of an arbitrary unknown single- qubit state in cavity QED is presented. Using a generalized Greenberger-Horne-Zeilinger （GHZ） state as the quantum channel among the three parties, the quantum information （i.e. the single-qubit state） from the sender can be split in such a way that the information can be recovered if and only if both receivers collaborate. Moreover, the scheme is insensitive to both the effects of thermal field and cavity decay.     

一维非线性光子晶体全光开关的数值研究

在光子晶体的缺陷层内掺入Kerr介质,基于Kerr非线性效应导致的缺陷态迁移原理,设计了两种一维光子晶体全光开关结构.应用时域有限差分（FD-TD）法,编制Matlab计算程序,对全光开关进行数值特性分析.讨论频率混合效应对全光开关的影响.观察光子局域效应增强光子晶体非线性的现象,验证了光子局域效应与光子晶体完整周期结构的层数有关,层数太少光子局域效应不明显.     

The design of a five-cell high-current superconducting cavity

Energy recovery linacs are promising for achieving high average current with superior beam quality. The key component for accelerating such high-current beams is the superconducting radio-frequency cavity. The design of a 1.3 GHz five-cell high-current superconducting cavity has been carried out under cooperation between Peking University and the Argonne National Laboratory. The radio-frequency properties, damping of the higher order modes, multipacting and mechanical features of this cavity have been discussed and the final design is presented.     

方程ü bu~r g(u(t-τ))=p(t)的2π-周期解(英文)

本文对一类不具耗散项的时滞微分方程进行了分析 ,利用重合度理论 ,得到了方程至少存在一个 2 π-周期解的充分条件