低功耗单双电源供电的轨对轨仪表放大器AD627

AD627是美国ADI公司出品的仪表放大器，它采用单双电源供电，具有轨对轨输出，并可用一个外部寄存器设定增益。可用于低功耗医用检测设备、热电耦放大器和便携式电池供电等仪器中。文章介绍了AD627的主要技术性能、工作原理、应用设计以及应用电路。     

基于AD9850的可编程信号源的设计

在通信、电子测量和教学实验等场合需要高精度、频率可变的信号源,现采用导致频率合成第二次革命的直接数字频率合成（DDS）技术实现可编程的信号源的方案。同时,也扩展为低频幅频特性测试系统的一个标准的扫频信号。     

太阳能发电机控制系统的温度采集电路设计

介绍了一种基于AD7606多路K型热电偶温度采集电路的设计,采用斯特林太阳能发电控制系统,运用热电偶与AD转换芯片AD7606组成温度采集电路,将采集好的数据经单片机进行数据处理后传送给上位机。实验结果表明,文中设计功能稳定、精度高,分辨率高的温度测量要求,达到了技术指标。     

基于AD2S83的编码

介绍ANALOG DEVICES公司的产品——AD2S83的工作原理，以及针对某天线的技术要求而做的基于AD2S83的编码应用。     

Determination of zolmitriptan enantiomers in rat liver microsomes by chiral high performance liquid chromatography with fl uorescence detection

A selective chiral high performance liquid chromatographic method was developed and validated to separate and quantify the enantiomers of a new potent selective 5-HT(1B/1D) receptor partial agonist, S-zolmitriptan, and its antipode in rat liver microsomes induced with beta-naphtho flavone. S- and R-zolmitriptan were extracted from rat hepatic microsomal incubates with chloroform/isopropanol (75:25, v/v), and were separated on a narrow-bore enantioselective normal phase Chiralpak AD-H column (250 x 0.46 mm) with hexane-isopropanol-triethylamine (72/28/0.25, v/v/v) as mobile phase and fluorescence detection with emission at 350 nm and excitation at 291 nm. The calibration curves were linear for R- and S-zolmitriptan concentration over the range 0.1-5.0 microg/mL (r = 0.9996 and 0.9999), and the limits of quantitation were 0.1 microg/mL. The metabolism and interaction of the enantiomers of zolmitriptan in treated hepatic microsomes were investigated using chiral HPLC. There was significant difference between the disposition of the S- and R-zolmitriptan when racemic zolmitriptan or single enantiomers of zolmitriptan were incubated for 5, 10 and 20 min, suggesting that the metabolism of zolmitriptan in rat liver microsomes is enantioselective. In addition, there was also a significant difference between the IC(50) of R- to S-zolmitriptan and S- to R-zolmitriptan (IC(50S/R)/IC(50R/S) = 45.2). This indicated that the disposition process favored the S-form of zolmitriptan.     

On the unusual solvent retention and the effect on the gas transport in perfluorinated Hyflon AD membranes

Dense membranes of Hyflon AD 60X were prepared by the solvent evaporation method and by melt pressing. The diffusion coefficient, solubility and permeability of the membranes were measured for six permanent gases using time lag and steady state permeation measurements. The thermal properties were determined by Differential Scanning Calorimetry (DSC) and the solvent content was measured gravimetrically and was estimated by the Fox equation. It was found that unusually strong solvent retention in the solution-cast membrane leads to considerable plasticization of the polymer, to possible foam formation upon drying and, most important, to significant changes in the permeation properties. The residual solvent increases the diffusion coefficient and permeability of the larger gas species up to almost one order of magnitude, and it reduces the permselectivity. For most gas species the solubility is about two times higher in the solvent-free melt-pressed film than in the solution-cast film. The relation between the residual solvent and the membrane properties is discussed.     

一种可回收配体[QN(OH)2]2PYDZ在烯烃不对称双羟化及氨羟化反应中的应用

一种可重复使用的非负载型金鸡纳生物碱衍生物配体与金属锇形成原位催化剂用于9种烯烃的不对称双羟化(AD)反应, 表现了很好的对映选择性(85%～＞99%)和反应活性(82%～91%). 将其用于催化65种烯烃不对称氨羟化(AA)反应, 也表现了好的对映选择性(6176%～＞99%)和反应活性(50%～72%). 并采用两种不同的方法进行AD和AA反应中配体的回收和重复使用. 结果表明两种方法均可有效地进行配体的再利用.     

高性能模拟前端AD7714及其应用

AD7714是一个完整的用于低频测量应用的模拟前端。其主要特点是:使用Σ-Δ转换技术,转换精度高;具有片内可编程增益放大器和低通数字滤波器;具有SPI通信接口等。通过实验,提炼出了AD7714技术说明书中没有明确的特性和技术指标,纠正了其中的错误,讨论了在应用上的技术要点、缺点,介绍了在“863”重点引导项目和安徽省“十五”重点攻关项目中的应用。     

微型短波信号发生器设计与实现

对采用DDS(直接数字频率合成)芯片和单片机设计一种精密微型短波信号发生器进行了可行性论证。简述了其基本原理,并着重于硬件角度的描述。当输入时钟信号为12.8 MHz时,输出频率上限可达30.72 MHz。设计利用现代数字化系统的优势,应用先进的DDS专用芯片AD8951与单片机配合控制,实现了频率、相位的准确输出,可靠性高。本设计适用于通信系统和高精度仪器。     

基于现场可编程门阵列的数控延时器的设计

给出一种基于现场可编程门阵列(FPGA)的数控延时器的设计方法.首先详细介绍使用计数器的串联实现可控延时的方法,接着讨论不同延时范围下该数控延时器的改进方案,最后分析延时误差及延时精确度.延时器的外部接口仿照AD9501设计.