Mass transfer kinetics of neodymium(III) extraction by calix[4]arene carboxylic acid using a constant interfacial area cell with laminar flow

BACKGROUND: Thermodynamics and kinetics data are both important to explain the extraction property. In order to develop a novel separation technology superior to current extraction systems, many promising extractants have been developed including calixarene carboxylic acids. The extraction thermodynamics behavior of calix[4]arene carboxylic acids has been reported extensively. In this study, the mass transfer kinetics of neodymium(III) and the interfacial behavior of calix[4]arene carboxylic acid were investigated. RESULTS: The rate constant (K_ao) becomes constant when the stirring speed was controlled between 250 rpm and 400 rpm. The activation energy (E_a) was calculated to be 21·41 kJ mol^?1 or 88·17 kJ mol^?1 (dependent on temperature) from the slope of log K_ao against 1000/T. The linear relationship between the specific area and the extraction rate is the characteristic of an interfacial reaction control. The minimum bulk concentration of the extractant necessary to saturate the interface (C_min) is lower than 4·19 × 10^?4 mol L^?1. CONCLUSION: The effect of stirring speed, temperature, and species concentration on the extraction rate demonstrates that the extraction regime depends on the extraction conditions. The chemical reaction control governs the extraction regime at temperatures below 303 K and a mixed control regime occurs when the temperature is between 303 K and 318 K. The probable locale for the chemical reaction is at the liquid–liquid interface and the rate equation is deduced to be: ? d[Nd³⁺]_(a)/dt = k_f[Nd³⁺]_(a)[H₄A]_(o)^0·727[H⁺]_(a)^?0·978. The rate‐controlling step was suggested by the analysis of the experimental results. Copyright © 2008 Society of Chemical Industry     

铁磁偶合的Gd（Ⅲ）Cu（Ⅱ）配合物──组装分子基铁磁体的一种重要元件

铁磁偶合的Ｇｄ（Ⅲ）Ｃｕ（Ⅱ）配合物──组装分子基铁磁体的一种重要元件缪明明，廖代正，王耕霖（南开大学化学系天津３０００７１）摘要分子基磁体的设计是自然界向化学家挑战的一个热点课题。铁磁偶合的Ｇｄ（Ⅲ）Ｃｕ（Ⅱ）配合物是组装分子基磁体的一种重要元件。...     

Clinical and experimental observation of xilixin granule combined with radiotherapy in treating malignant-tumors

Thirty six patients of pulmonary or nasopharyngeal carcinoma were treated with Xilixin granule (XLXG) combined with radiotherapy and compared their efficacy with that of 31 patients treated by Zhenqi Fuzheng granule combined with radiotherapy for control. Results showed that the symptoms of Yin Deficiency syndrome in treated group were obviously improved, the leucocyte decreased by 5.6%, while in control group it reached 25.8%, the 3 year survival rate was significantly higher in treated group (75.0%) than that in control group (51.6%). Animal experiment revealed that XLXG had the effects of tumor inhibition, it could increase white blood cells, platelets and hemoglobin of patients, especially in using large dosage. These results suggested that XLXG have some protective effect against radiotherapeutic damage in patients with malignant tumor.     

应用硫酸铵提高乌拉嗄金矿石浮选回收率试验研究

经试验发现应用一种化学肥料硫酸铵可以显著提高乌拉嘎金矿石的浮选回收率。闭路试验尾矿工艺矿物学鉴定证明，以硫酸铵作为调整剂的浮选过程中，微细粒单体金和金与石英边生体被有效回收。     

伊犁盆地生成发展概述

本文对伊犁盆地的生成和发展做了初步探讨,认为它是在前震旦纪结晶基底之上经历了较长时间的抬升之后形成和发展起来的双层结构盆地,即石炭纪体内裂谷盆地,石炭纪后山间陆相盆地。     

High-temperature hydrothermal systems in West Yunnan Province, China

There are more than 660 thermal springs in West Yunnan Province, 30 of which are high-temperature hydrothermal systems with reservoir temperatures above 150°C.All thermal springs in West Yunnan are under the control of the tectonics, most of them being distributed at anticlinoria of metamorphic rocks and granites. This paper discusses the relationship between thermal areas and tectonics, the correlation between thermal springs in West Yunnan and North Thailand, and the geothermal prospects in West Yunnan.     

Simulation of programmable logic controller

The development and test of a PLC control program takes time, increases equipment down-time, and might damage hardware due to program errors. All of these problems can be eliminated if there is a computer simulation system for testing control programs off line. This paper presented a new method, called Direct Sequential Method, for simulating PLCs. This method resolves a ladder logic sequentially by applying a series of logic deductions. This simulation system has been implemented in C and tested successfully.     

河道堤防老化指标体系评定之浅见

水利工程老化、失修是当前工程不能发挥正常效益的主要原因,建立工程老化指标评价体系是解决该问题的基础工作之一。老化是工程建成后在自然因素和人为活动长期连续的作用下,工程效益衰减、构件功能降低及材料性能逐渐变坏的自然现象。河道堤防以土石为主要材料,应以工程的功能为主建立老化指标体系。依据对工程效益和安全的影响程度,水利工程的综合老化度可分为四级。工程损坏后,在防洪工程运用年度内未能修复称为水利工程失修。解决老化问题主要依靠折旧或大修费,而解决失修问题主要依靠运行管理和维修养护费。     

百色盆地林蓬浅层稠油油藏热采开发的可行性研究

百色盆地林蓬油藏为一浅、薄、低产、低渗的普通稠油构造油藏。通过对油藏特征、原油热物性、热采数值模拟初步分析及热米开发经济效益的初步评价，认为林蓬油藏利用我国现有的热采技术投入开发具有可行性，并提出了具体实施方案和工作意见．