Role of interaction between selenium and organic matters on causes of Kaschin-Beck disease

Influences of organic matters of soil and water on speciation and biological utilization of selenium are discussed. Humic acid is found to be the main pool of selenium in soil and affects the bio-availability of the element in soil-plant system. Fulvic acid from drinking water inhibits the absorption of selenium taken from diet. The relationship between high content of organic matters of water and selenium deficiency on the causes of KBD could be reflected in the limited synthesis of glutathione peroxidase, which is generally stimulated by fulvic acid from drinking water.     

超塑性材料轴对称镦粗时的变形力计算

本文探讨了变分理论在超塑性成形方面的应用,建立了适合超塑性材料的变分理论的基本方程,并比超塑性材料轴对称镦粗为例验证了这些方程的正确性。     

Spatial and temporal distribution of total ozone over China

１　ＩｎｔｒｏｄｕｃｔｉｏｎＯｚｏｎｅｉｓｏｎｅｏｆｔｈｅｔｒａｃｅｇａｓｅｓｉｎａｔｍｏｓｐｈｅｒｅ．Ｉｔｃａｎａｂｓｏｒｂｎｅａｒｌｙａｌｌｓｏｌａｒｕｌｔｒａｖｉｏｌｅｔｒａｄｉａｔｉｏｎ（ＵＶＢ）ｒａｎｇｅｄｆｒｏｍ０－２０—０－３５μｍ．Ｔｈｅｃｈａｎｇｅｏｆｓｔｒａｔｏｓｐｈｅｒｉｃｏｚｏｎｅｃｏｎｃｅｎｔｒａｔｉｏｎａｎｄｉｔｓｖｅｒｔｉｃａｌｓｔｒｕｃｔｕｒｅｗｉｌｌｉｎｆｌｕｅｎｃｅｔｈｅｔｅｍｐｅｒａｔｕｒｅｓｔｒｕｃｔｕｒｅｏｆｓｔｒａｔｏｓｐｈｅｒｅ．Ｔｈｅｄｅｃｒｅａ…     

福建龙岩中甲锡多金属矿床构造控矿特征

中甲锡多金属矿床是受政和一大埔断裂带的低序级构造所控制的矿床。控矿构造研究表明，锡矿化及矿体主要受NE－NNE、NW向断裂、裂隙以及接触带构造的复合控制，构造变形以服性—脆韧性为主，构造控矿型式多样并决定矿（化）体的空间定位方式，形成高中温热液型、破碎蚀变岩型、斑宕型锡多金属矿床，成为中甲锡多金属矿床的重要成矿地质条件之一。     

利用塑性介质挤胀成形三通管接头变形力的研究

此文对利用塑性介质挤胀成形三通管接头变形力进行了实验研究。设计了一套挤胀成形三通管接头的通用装置,并利用此装置进行了三通挤胀成形实验。此研究给出了影响成形过程的一些重要参数。将理论结果与实验结果进行了对比,两者吻合较好。     

高应变速率反挤压超塑Zn-Al_(22)合金管材

此文简要地叙述了工业性试生产Zn-Al_(22)超塑性管材的工艺流程。采用慢速等液面浇注法和几次均匀化处理实现晶粒细化。在ε=2×10~(-2)S~(-1)的高应变速率下进行反挤压Φ49×2.25×250mm管材1200只,超塑性能最高值δ=1620％,流变应力σ_b=2.36MPa。     

能见度的降低与大气污染的关系

根据重庆十年能见度及气象数据和大气监测数据,作出了不同风向上能见度玫瑰图和多元回归模型.结果显示,水平能见度距离的降低,主要是空气污染引起的.     

Diffusion and adoption of environmentally sound technology in China cement industry

ＤｉｆｕｓｉｏｎａｎｄａｄｏｐｔｉｏｎｏｆｅｎｖｉｒｏｎｍｅｎｔａｌｙｓｏｕｎｄｔｅｃｈｎｏｌｏｇｙｉｎＣｈｉｎａｃｅｍｅｎｔｉｎｄｕｓｔｒｙＣａｉＮｉｎｇＥｃｏｎｏｍｉｃｓＤｅｐａｒｔｍｅｎｔ，ＺｈｅｊｉａｎｇＵｎｉｖｅｒｓｉｔｙ，Ｈａｎｇｚｈｏｕ...     

机械零件的粉末冶金成形方法

此文主要介绍了几种较实用和新发展的机械零件的粉末冶金成形方法,包括Olivetti法,螺旋形状零件成形法,粉末注射成形,组合烧结成形,粉末锻造和旋转锻造。     

Studies on catalytic reduction of nitrate in groundwater

Catalytic reduction of nitrate in groundwater by sodium formate over the catalyst was investigated. Pd-Cu/γ-Al₂O₃ catalyst was prepared by impregnation and characterized by brunauer-emmett-teller (BET), inductive coupled plasma (ICP), X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive X-ray (EDX). It was found that total nitrogen was effectively removed from the nitrate solution (100 mg/L) and the removal efficiency was 87%. The catalytic activity was affected by pH, catalyst amount used, concentration of sodium formate, and initial concentration of nitrate. As sodium formate was used as reductant, precise control in the initial pH was needed. Excessively high or low initial pH (7.0 or 3.0) reduced catalytic activity. At initial pH of 4.5, catalytic activity was enhanced by reducing the amount of catalyst, while concentrations of sodium formate increased with a considerable decrease in N₂ selectivity. In which case, catalytic reduction followed the first order kinetics. Translated from Acta Scientiae Circumstantiae, 2006, 26(4): 567–571 [译自: 环境科学学报]