ICP－AES法测定栽培灵芝中9种微量元素

本文报导了采用美国ＬｅｅｍａｎＬａｂｓ公司生产的ＰＳ－Ⅰ型中阶梯光栅光谱仪，对栽培灵芝中Ｇｅ、Ｃａ、Ｍｇ、Ｚｎ、Ｃｕ、Ｍｎ、Ｆｅ、Ｋ、Ｎａ等元素进行了测定。为防止Ｇｅ的挥发损失，采用了ＨＮＯ３－ＨＣｌＯ４低温湿法消化的前处理方法。相对标准偏差为１．３１％－９．１１％，回收率为９１．０％－１１０．０％，结果令人满意。     

Dielectronic recombination of positive ions—I. A generalized cascade theory

A generalized theory of dielectronic recombination is formulated, explicitly incorporating the higher-order effect of cascade transitions to all the captured final states which are stable against Auger emission. The previously-used rate formulas contain only the two-step process of target excitation followed by a single radiative transition. The formal reaction theory is employed to precisely define the contribution of the successive open channels to energy shifts and resonance widths. Correct expressions are derived for the radiative and Auger branching ratios associated with each stage of the cascade. Various angular momentum averaging procedures and the effect of the spectator electrons in the participating subshells are discussed.     

Dielectronic recombination of positive ions—III. Rate coefficients for Mo32+

Dielectronic recombination rate coefficients for Mo³²⁺ recombining to Mo³²⁺ are given for electron temperatures of 1.4, 2.8, and 5.6 keV. Nonrelativistic results in the resonance approximation were obtained and tables of selected Auger (A_a) and radiative (A_r) rates, fluorescence yields, and dielectronic recombination rates are given. Excitation of 2p electrons to higher shells is found to be dominant over other transitions including direct capture at the temperatures considered. The effect of the cascade transitions is estimated to be of the order of 30%. Different angular momentum averaging procedures change the results very significantly.     

Hybrid electrokinetic manipulation in high-conductivity media

This study reports a hybrid electrokinetic technique for label-free manipulation of pathogenic bacteria in biological samples toward medical diagnostic applications. While most electrokinetic techniques only function in low-conductivity buffers, hybrid electrokinetics enables effective operation in high-conductivity samples, such as physiological fluids (～1 S m(-1)). The hybrid electrokinetic technique combines short-range electrophoresis and dielectrophoresis, and long-range AC electrothermal flow to improve its effectiveness. The major technical hurdle of electrode instability for manipulating high conductivity samples is tackled by using a Ti-Au-Ti sandwich electrode and a 3-parallel-electrode configuration is designed for continuous isolation of bacteria. The device operates directly with biological samples including urine and buffy coats. We show that pathogenic bacteria and biowarfare agents can be concentrated for over 3 orders of magnitude using hybrid electrokinetics.     

An efficient nickel-catalyzed alkenylation of functionalized benzylic halides with alkenylaluminum reagents

Highly efficient and simple coupling reactions of benzylic bromides or chlorides with alkenylaluminum reagents catalyzed by NiCl(2)(PPh(3))(2) are reported. The coupling reactions proceed effectively at room temperature employing low loading of catalyst, 0.5 mol% for benzylic bromides having either electron-donating or -withdrawing substituents on the aromatic ring, affording coupling products in excellent yields of up to 94% in short reaction times. The coupling reactions of benzylic chloride require 5 mol% of the catalyst and a longer reaction time of 2 h.