Extraction of penicillin G from simulated media by an emulsion liquid membrane process

The extraction of penicillin G from simulated media was performed by water/oil/water (w/o/w) emulsion liquid membranes (ELMs) and studied under various operational conditions in a batch system. The degree of extraction achieved was between 80% and 95% under specific conditions. A concentration of greater than nine times the initial concentration of penicillin G in the external phase was obtained in the internal phase. The pH of the internal aqueous solution, containing a basic salt, was theoretically calculated on the basis of the amount of penicillin G transported into the internal phase. The calculated results agreed with the experimental data well and were used to select a suitable type and concentration of a basic salt in the internal phase to give a pH within the range 5 to 8 where penicillin G was stable after the termination of extraction. The extraction of penicillin G was successfully performed by the ELM process with sodium carbonate in the internal phase.     

Production of perovskite-like La1−xCaxMnO3+δ ferromagnetic thin films by electrochemical reduction

Ferromagnetic and perovskite-like thin films (<1m) of La1–xCaxMnO3+ have been routinely prepared by heat treatment of an amorphous La–Ca–Mn precursor. The precursor was electrodeposited cathodically in the absence of oxygen and water onto polished silver substrates from a nonaqueous solution of the components' nitrates. Analysis by X-ray diffraction and SQUID magnetometry shows these materials exhibit the appropriate structural and magnetic phases indicative of colossal magnetoresistance.     

PLC在高浓度冲稀自动控制系统的应用

本文在介绍高浓度冲稀自动控制系统的工作原理、特点、系统调校及日常维护要点的基础上,探讨了PLC在这种类型的系统中的应用。     

3G网络基站电磁环境影响分析

通过资料收集、理论预测、数据监测与分析,讨论了辽宁某市3G网络基站中典型基站的电磁环境。结果表明,理论预测与实际监测结果差距不大,各典型基站的电磁辐射功率密度均低于国家标准限值8μW/cm2,对该地区的电磁环境影响不大。对保护环境提出了相应的对策措施.     

飞思卡尔典型传感器的应用

本文所涉及的飞思卡尔公司的两款典型芯片作为此次飞思卡尔技术论坛设计应用大奖赛的指定参赛芯片,在业界享有极高的声誉。本文希望通过对这两款传感器应用的探讨,激发读者的设计灵感,也希望读者朋友能够积极参加这一飞思卡尔公司的环保赛事,在比赛中取得好成绩。     

第三代移动通信系统中应用的LDMOS器件

介绍了在第三代移动通信系统的基站中应用的 LDMOS器件的现状及关键技术     

3.5G、LMDS无线接入技术的业务特性

本对目前常用的3．5G、LMDS设备的业务平台、业务特性及对某些特殊业务支持能力进行了探讨。     

以3G为核心的通信新技术综述

随着第三代移动通信标准的发展,涌现出各种新兴的通信技术,它们所带来的变化是巨大的,影响是深远的。这些技术进步是革命性的,它大大提高并拓展了人与人、人与机器甚至机器与机器之间的通信能力,并进一步挖掘了通信潜力。该文主要系统分析了3G中采用的通信新技术,并对这些新技术的应用前景进行了展望。