新型配位聚合物[Zn（tca）2（4,4′-bpy）]的合成、晶体结构及荧光性质

利用水热法合成了新型配合物[Zn(tca)2(4,4′-bpy)](tca=trans-cinnamic acid,4,4’-bpy=4,4’-bipyridine).通过元素分析、红外、荧光和单晶X-射线对配合物进行了结构和性质表征.结构测定显示配合物属六方晶系,P-3空间群.配体tca呈现2种配位模式,分别是顺-顺桥式双齿和螯合双齿,最终配合物形成新颖的三维结构.性质测定表明配合物具有蓝色荧光性质.     

Analysis of alkyl polyglucosides in industrial products by capillary electrophoresis with pulsed amperometric detection

Pulsed amperometric detection following micellar electrokinetic chromatography has been applied successfully to the direct detection of alkyl polyglucosides (APGs) in shampoos and other industrial products without prior conversion to highly absorbing or fluorescing derivatives. For electrochemical detection, it is necessary to dissociate the hydroxyl groups of the APGs. Thus, we used 0.1 M NaOH in the outlet vial to dissociate the APGs. The main problems associated with the combination of electrochemical detection and capillary electrophoresis are the need to isolate the detector from the electric field used in the capillary electrophoresis separation and the difficulty of aligning the working electrode with the end of the capillary. To overcome these problems, a simple capillary-electrode holder was constructed. This holder automatically aligns the capillary and the electrode in a wall-jet configuration without the aid of micropositioners and facilitates the replacement of electrodes and capillaries without reconstruction of the entire capillary/electrode setup. Special microcylindrical gold electrodes have been produced by sealing 300-μm-diameter gold wire into borosilicate-glass capillaries.     

Single-transverse-mode active multi-mode- interferometer 1.45 μm high power laser diode

Active multi-mode interferometer (MMI) laser diodes were realized in InGaAsP/InP for high-power applications. They achieved increases in output powers of 90 mW, which correspond to 30% increases, as compared to the powers of regular single-lobe laser diodes fabricated simultaneously with the active MMI-LDs. The resulting maximum powers of the active MMI-LDs were 380 mW at a wavelength of 1.45 μm. The implemented active MMI-LDs showed stable regular single-transverse-mode outputs up to the maximum power. Received: 16 May 2001 / Published online: 30 October 2001     

Comparative study of the hydrolysis of a third- and a first-generation platinum anticancer complexes

The hydrolysis of cis-[Pt(NH₃)₂Cl₂] (cisplatin) and of the third-generation platinum anticancer compound (cis-[PtCl₂(NH₃)-(2-picoline)] (picoplatin) has been studied quantum-mechanically using density functional theory (mPW1PW91). Due to its asymmetry, picoplatin is an interesting case, since hydrolysis may proceed through two distinct reaction paths and with the entering water molecule sin or anti to the methyl group of 2-picoline. Solvent effects were taken into account either by applying the polarizable continuum model (PCM) solvent approach or by introducing a cluster of water molecules solvating the complex. With the PCM approach, it emerges that the steric hindrance of 2-picoline has a minimum impact on the activation barriers for picoplatin hydrolysis, since the water molecule approach is far from being axial and far from the methyl group. Accordingly, the TS state geometry with 5-coordinated platinum is not significantly more distorted than in the cisplatin case. Our results point out that the use of separated reactants as reference for energy barrier gives satisfactory results for each compound and produces correct relative magnitudes of first and second hydrolysis rate constants for each compound. However, this model is not able to predict the generally faster hydrolysis experimentally observed for cisplatin with respect to picoplatin. The study of the first hydrolysis step for the two compounds in the presence of explicit water molecules shows that the entering water molecule is strongly interacting with the others through a complex hydrogen bond network. The discrete solvation model is able to correctly predict a slightly slower hydrolysis of picoplatin highlighting the need of explicit solvation to predict small differences (within an order of magnitude) in the observed rate constants.     

Some notes on identities for Dirichlet L-functions

Let q ≥ 3 be an integer, and χ be a Dirichlet character modulo q, L(s, χ) denote the Dirichlet L-function corresponding to χ. In this paper, we show some early information on the mean value of the Dirichlet L-functions and give some new identities for     

Fractional order modeling of rotor skin effect in induction machines

This paper presents a fractional Park model which is intended to characterize skin effect of squirrel cage induction machines. Usual modeling of skin effect is based on a ladder network; it is demonstrated that a fractional impedance is an alternative to this ladder network. The fractional Park’s model has been validated by output error identification. A methodology has been proposed to select the more appropriate fractional model of the rotor, respecting the diffusive nature of skin effect.     

Path tracking design based on Davidson–Cole prefilter using a centralized CRONE controller applied to multivariable systems

To perfectly govern MIMO (Multi-Input Multi-Output) processes, a fully populated matrix controller has been developed due to its flexibility. Taking into account the plant uncertainties, the CRONE (Commande Robuste d’Ordre Non Entier) control approach is used with the non-diagonal quantitative feedback theory (QFT) procedure. The MIMO-QFT robust synthesis methodology has been used in order to generate the appropriate equivalent MISO (Multi-Input Single-Output) system structure from the MIMO plant. For each MISO structure, the CRONE control approach based on third-generation CRONE methodology is used to find the diagonal elements of the controller of the plant while considering the plant uncertainties. The non-diagonal part of the controller is determined to reach the aim of minimizing the coupling effects. After that, a fractional prefilter synthesis approach is developed to find the non-integer prefilter expression satisfying the tracking specifications. A SCARA robot manipulator has been used to verify the designed controller performances.     

High efficiency second-harmonic generation in KNbO3 crystals

Second-harmonic generation in KNbO₃ crystals has been studied with CW and pulsed Al_xGa_1?xAs and dye lasers. High conversion efficiencies were obtained by noncritical Type I phase-matching at room temperature for the wavelength λ_PM = (860±2) nm using the nonlinear optical coefficient d₃₂ = 21 pm/V. The measured peak power was P_2ω=13.6 μW for a fundamental power P_ω=21 mW with a crystal of l = 8.97 mm in length. The phase-matching wavelength in the orthorhombic phase of KNbO₃ can be temperature tuned between 838 nm (for T = -36°C) and 950 nm (for T = +180°C).     

An Empirical Correction Term to Density Functional Theory for the Description of the TiCl4-Lewis Base Complexes

Calorimetric and computational investigation on the interaction of TiCl₄ with some Lewis bases (esters and ethers) is presented. The bases were chosen for their relevance in heterogeneous Ziegler-Natta polymerization of propene. Comparison of the theoretical data with the calorimetric data indicates that calculations consistently underestimate the experimental binding energies. In light of this consistency, we propose that an empirical correction term added to the theoretical binding energies could represent an empirical solution for the prediction of the TiCl₄/donor binding energies with reasonable accuracy.