Investigation on False Peak Phenomena in On-line Sweeping Technique in MEKC

ＩｎｔｒｏｄｕｃｔｉｏｎＭｉｃｅｌｌａｒｅｌｅｃｔｒｏｋｉｎｅｔｉｃｃｈｒｏｍａｔｏｇｒａｐｈｙ (ＭＥＫＣ)ｗａｓｉｎｖｅｎｔｅｄｔｏｅｘｔｅｎｄｔｈｅｕｔｉｌｉｔｙｏｆｃａｐｉｌｌａｒｙｅｌｅｃｔｒｏｐｈｏｒｅｓｉｓ(ＣＥ)ａｎｄｐｅｒｍｉｔｔｅｄｔｈｅｓｅｐａｒａｔｉｏｎａｎｄａｎａｌｙｓｉｓｏｆｎｅｕｔｒａｌｃｏｍｐｏｕｎｄｓ .ＢｕｔｊｕｓｔｌｉｋｅｏｔｈｅｒｍｏｄｅｓｏｆＣＥ ,ＭＥＫＣａｒｅｈａｍｐｅｒｅｄｂｙｔｈｅｌｏｗｃｏｎｃｅｎｔｒａｔｉｏｎｓｅｎｓｉｔｉｖｉｔｙｏｆｔｈｅｕｌｔｒａ …     

基于紫外光刻的双轴张应变Ge/SiGe多量子阱电吸收调制器北大核心CSCD

采用紫外光刻工艺(ultraviolet lithography technique,UVL),在互补金属氧化物半导体(complementary metal oxide semiconductor,CMOS)兼容的硅基平台上制作了基于悬空微桥结构在Ge/SiGe多量子阱材料中引入双轴张应变的低偏振相关电吸收调制器。利用拉曼光谱测试了器件引入双轴张应变的大小,并对器件在横电(transverse electric,TE)偏振和横磁(transverse magnetic,TM)偏振下的光电流响应、调制消光比和高频响应等性能进行了测试。器件的低偏振相关消光比在0 V/4 V工作电压下可达5.8 dB,3 dB调制带宽在4 V反向偏置电压时为8.3 GHz。与电子束光刻工艺(electron beam lithography technique,EBL)相比,采用UVL制作的器件在调制消光比、高频响应带宽等性能上略差一点,但具有曝光时间短、成本低和可大批量生产等优势,应用前景广阔。     

SOME BLENDING INTERPOLATION METHODS IN CAGD

Some of the blending interpolation methods (which) stated by a convex combination technique are presented. This includes C1 ,C2 blending triangular interpolanls and C1 -blending quadrilateral inter polanls for surfaces. The mentioned methods can be generalized to the construction of C" blending interpolants.     

KZnF3：Eu^3＋单晶生长及光谱特性

利用Ｂｒｉｄｇｍａｎ－Ｓｔｏｃｋｂａｒｇｅｒ方法在氩气气氛下生长出ＫＺｎＦ３：Ｅｕ＾３＋单晶，测定了晶体的激发光谱、荧光发射光谱和ＥＳＲ谱，讨论了Ｅｕ离子的取代格位。     

三羰基铬苯乙烯甲酰衍生物的质谱研究

近年来,随着对金属有机化合物的研究的不断深入,人们对它们的兴趣已由对结构、化学性质的探讨而扩展到对物理性质的研究,如磁性质、导电性、光学性质,并从中发现某些金属有机化合物,如某些芳基三羰基铬络合物及二     

高效液相色谱-电感耦合等离子体发射光谱联用的瞬时信号采集和处理软件及实际应用

本文对高效液相色谱-电感耦合等离子体原子发射光谱联用技术进行了研究.对所用ICAP-9000型等离子体原子发射光谱仪的控制采样程序进行了部分修改,采集的数据通过异步串行通讯方式由AppleⅡ微机传送至IBM PC286机进行处理。发展的瞬时信号采集程序能满足HPLC的检测要求,并将这一联用技术成功的用于砷的形态分析.     

一阶导数停流法测定药物和饮用水中的铁

本文利用Ｆｅ＾３＋离子催化Ｈ２Ｏ２氧化四甲基对苯二胺的反应，将采用停流技术获得的动力学曲线转换成一阶导数曲线，根据导数峰高值与Ｆｅ＾３＋离子浓度的线性关系测定药物和自来水中的含量，本方法的线性范围为４．０－４０．０ｎｇＦｅ＾３＋／ｍｌ，相对标准偏差小于２．５％，标准加入回收率在９８．７％－１０１％之间，检测限为１．９２ｎｇＦｅ＾３＋／ｍｌ。对照实验结果表明，导数动力学法比一般非导数动力学法具有线关     

Silicate Xerogels with Dopant-Induced Chirality

A series of silicate xerogels with entrapped chiral amino acids have been obtained via sol-gel technology. The transparent, glassy samples obtained exhibit chirality in the bulk due to the presence of the entrapped asymmetric molecules. Measurements of the optical activity of the doped xerogel samples revealed that the entrapment did not significantly influence the optical activity observed for liquid solutions of the amino acids. Thus, the sol-gel method enables the preparation of amorphous optical materials exhibiting properties of strictly spatially defined molecular systems. Apart from the obvious optical applications, such porous materials with asymmetric centers might find interesting applications in chiral chemical syntheses and separations.     

Underpotential deposition studies of copper on glassy carbon

Studies on the deposition and dissolution of copper from 0·5 M sulphuric acid solutions onto glassy carbon (GC) using potential sweep techniques indicated that an additional peak occurs at higher positive potentials than the bulk stripping peak. This peak is identified as due to the stripping of underpotential deposited (UPD) copper. Results of investigations on the effect of sweep rate, deposition potential and time of deposition on the peak characteristics of UPD and bulk deposited copper are also reported.     

New stationary phases of conjugated π-electron systems for HPLC—characterization of structure and dynamics by solid state NMR spectroscopy

Four new stationary phases for HPLC were prepared by modifying silica gel with a trifrnctional aminoalkyl silane. A conjugated π-electron system was linked to the amino group either directly or with a carboxylic anhydride as a spacer in between. Characterization and dynamic measurements of the new stationary phases were performed by solid state NMR spectroscopy. The results of the ²⁹si and ¹³C CP/MAS techniques were compared with the recently developed ¹H MAS-only technique. Despite strong homonuclear dipole-dipole interactions it was possible to obtain well resolved ¹H MAS spectra of those stationaru phases with a high degree of crosslinking. Limited mobility of the aromatic ligand fragments is common for all examined stationaryu phases. The chromatographic properties of the new phases were tested by their ability tio sepatate a mixture of eight PAHS. It could be shown that the π-π interaction mechanism is responsible for the separation of the eight PAHs, because the elution order of the PAHs did not changem despite the use of both a nonpolar mobile phase (n-heptane) and a polar mobile phase (methanol/ water mixture).