Synthesis and X-ray structure studies of complex [Cu(o-phenanthroline)2 (saccharin)] · (saccharin) · 2 H2O

The title compound has been synthesized and its crystal structure determined at room temperature, M_r = 824.34, triclinic, space group P–1(2), a = 13.622(4), b = 13.770(4), c = 11.167(3) Å; α = 104.83(2), β = 110.01(2), γ = 62.04(2) degree; U = 1727.0(9) ų, Z = 2, D_calc = 1.59 g/cm³. The final R is 0.066 for 3299 independent observed reflections with I ≧ 3σ(I). The crystal structure consists of repeated [Cu(o-phen)₂(sac)]⁺ cations, non-coordinated saccharin anion and two lattice water. And the central ion Cu²⁺ forms a trigonal-bipyramidal stereochemistry.     

1,2-聚丁二烯长链支化的研究

本文研究了1,2-结构含量在80～90%的1,2-聚丁二烯的长链支化,发现聚合物的立体规整性与聚合物的分子量无关,可以用GPC-自动粘度计联用技术研究其长链支化,产生支化的临界分子量为40万左右。     

Determination of the Activity Coefficients of NaCl in the System NaCl–NH4Cl–H2O

Using ion-selective electrode(s) (ISE) the activity coefficients of NaCl in the system NaCl–NH₄Cl–H₂O at 10, 25, and 40°C were measured by a computer-controlled automatic titration system. The ionic strength fractions of NH₄Cl were 0.2, 0.4, 0.6, and 0.8, respectively. It was found that the influence of the NH₄⁺ cation on the Na glass ISE was small enough to be neglected up to 3.0 mol-kg^-1. The Pitzer equation was adopted to calculate the activity coefficients of NaCl in this system and compared with the experimental data. Comparison of results indicates that the Pitzer parameters correlated from solubility data are suitable for calculating the activity coefficients for this system within the saturated solutions.     

高能激光束在线测量系统的光强衰减设计

针对环形光刀取样式高能激光束在线测量系统应用中光电探测器线性饱和功率密度低而被测高能激光功率密度高的特点,采用对取样激光扩束和介质膜衰减片级联衰减的方式,实现了数千倍的线性光强衰减。介绍了环形光刀扫描取样及其扩束衰减原理,并对介质膜衰减片在激光入射角 0°~15° 和功率密度1~1 000 W/cm2条件下的透过率特性进行了分析,用实验验证了该光强衰减设计的有效性。     

关于大学物理实验几个教学环节的探讨

针对现阶段大学物理实验课中存在的问题 ,提出在实验课教学中应注意的几个教学环节 ,从而达到教学目的 ,得到更好的教学效果     

Synthesis, structure and catalytic activity of alkali metal-free bent-sandwiched lanthanide amido complexes with calix[4]-pyrrolyl ligands

Simple silylamine elimination reactions of calix[4]-pyrrole [R(2)C(C(4)H(2)NH)](4) (R = Me (1), {-(CH(2))(5)-}(0.5) (2)) with 2 equiv. of [(Me(3)Si)(2)N](3)Ln(μ-Cl)Li(THF)(3) (Ln = Nd, Sm, Dy) in reflux toluene, afforded the novel dinuclear alkali metal-free trivalent lanthanide amido complexes (η(5):η(1):η(5):η(1)-R(8)-calix[4]-pyrrolyl){LnN(SiMe(3))(2)}(2) (R = Me, Ln = Nd (3), Sm (4), Dy (5); R = {-(CH(2))(5)-}(0.5), Ln = Nd (6), Sm(7)). The complexes were fully characterized by elemental analyses, spectroscopic analyses and single-crystal X-ray analyses. X-ray diffraction studies showed that each lanthanide metal was supported by bispyrrolyl anions in an η(5) fashion and along with three nitrogen atoms from N(SiMe(3))(2) and two other pyrroyl rings in η(1) modes formed the novel bent-sandwiched lanthanide amido bridged trivalent lanthanide amido complexes, similar to ansa-cyclopentadienyl ligand-supported lanthanide amides with respect to each metal center. The catalytic activities of these organolanthanide complexes as single component l-lactide polymerization catalysts were studied.     

Highly efficient and reusable dendritic catalysts derived from N-prolylsulfonamide for the asymmetric direct aldol reaction in water

The direct aldol reactions catalyzed by chiral dendritic catalysts derived from N-prolylsulfonamide gave the corresponding products in high isolated yields (up to 99%) with excellent anti diastereoselectivities (up to >99:1) and enantioselectivities (up to >99% ee) in water. In addition, catalyst 1e may be recovered by precipitation and filtration and reused for at least five times without loss of catalytic activity.     

细胞无机化学研究中需要关注的几个方面

本文评述了当前细胞无机化学研究中的几个方面,主要是包括钙离子和稀土离子在内的金属离子和活性小分子对细胞膜离子通道、膜受体蛋白、胞内受体蛋白以及对细胞功能的影响.     

Constraint qualifications for constrained Lipschitz optimization problems and applications to a MPCC

Three constraint qualifications (the weak generalized Robinson constraint qualification, the bounded constraint qualification, and the generalized Abadie constraint qualification), which are weaker than the generalized Robinson constraint qualification (GRCQ) given by Yen (1997) [1], are introduced for constrained Lipschitz optimization problems. Relationships between those constraint qualifications and the calmness of the solution mapping are investigated. It is demonstrated that the weak generalized Robinson constraint qualification and the bounded constraint qualification are easily verifiable sufficient conditions for the calmness of the solution mapping, whereas the proposed generalized Abadie constraint qualification, described in terms of graphical derivatives in variational analysis, is weaker than the calmness of the solution mapping. Finally, those constraint qualifications are written for a mathematical program with complementarity constraints (MPCC), and new constraint qualifications ensuring the C-stationary point condition of a MPCC are obtained.