Effects of Hg and Cu on the activities of soil acid phosphatase

Comparative study on the activity and kinectic properties of acid phosphatase (ACPase) of three soils amended with Hg and Cu at constant temperature and humidity was carried out. The results indicated that the inhibition on ACPase of the three sample soils by Hg and Cu varied with the content of soil organic matter and pH, where, Soil 1 was the most seriously contami- nated due to its lowest content of organic matter and the lowest pH among three samples, Soil 2 took the second place, and Soil 3 was the least contaminated. Except Soil 3, the activity of soil ACPase tended to increase along with the contact time under the same type and the same concentration of heavy metal. In particular the Vmax values of ACPase in all three samples decreased with increasing Hg and Cu concentration, whereas the Km values were affected weakly. According to the change of Vmax and Km values, Cu and Hg had the same inhibition effect on soil ACPase. Both of them may be a type of compound of non-competitive and anti-competitive inhibition. Statistic analyses indicated that activities of soil ACPase and Vmax values could serve as bioindicator to partially denote the heavy metal Hg and Cu contamination degree.     

基于S7-1200PLC的金属打包机控制系统研究

利用S7-1200PLC和MCGS触摸屏实现了对液压金属打包机的全自动控制,其中设计了打包环节的部分控制程序,将传送带送料替代人工送料,改翻包出包为前门推包出包。仿真实验表明,系统稳定可靠,安全性和生产效率较高。     

螯合离子色谱法测定茶叶中过渡金属及重金属含量

利用选择性螯合树脂和磺酸型交换树脂，在线将样品中的阴离子，碱金属，碱土金属，三价金属离子除去，同时浓缩富集待测的过渡金属，选择适当的梯度淋洗体系，将pb^2 ,Cu^2 ,Cd^2 ,Co^2 ,Zn^2 和Ni^2 等六种金属离子分离，继用在线柱后检测，检测限（信噪比为3：1）为ngmL^-1级甚至更低，并成功地应用于茶叶中过渡金属的测定。     

Adsorption of Cu^2 ＋, Zn^2＋ and Cd^2＋ on Bacillus subtilis

A process of biosorption of Cu2 , Zn2 and Cd2 on Bacillus subtilis was investigated. The experiments show that the process of biosorption is quite fast. The maximum adsorption was reached after 5 min and hardly changed with time. The experimental data was analyzed using four sorption kinetic models: the pseudo-first-order, the Ritchie second-order, the modified second-order and the Elovich equations, which helped to determine the best-fit equation for the sorption of metal ions onto biomass. The results show that both the Ritchie second-order and modified second-order equations can fit the experimental data. The Langmuir model is able to accurately describe adsorption of Cu2 and Zn2 on B. subtilis. The experimental data points of adsorption Cd2 and Zn2 on B. subtilis are described by Freundlich isotherms model.     

金属烤瓷修复体602例临床分析

目的 通过对金属烤瓷修复体的追踪检查，总结修复成功的关键要素。方法 常规牙体制备、取印模、灌模、制作暂时冠、比色、试戴、调He、粘固等系列步骤，对602例1512个牙进行金属烤瓷冠修复。结果 通过5个月至5年5个月的追踪检查，发现 其中32个修复体有瓷裂纹或瓷折裂现象(2．1％)，18个修复体边缘不太密合(1．19％)，8个修复体龈缘金属显露(0．5％)，12个修复体发生龈缘炎或龈萎缩(0．75％)，4个修复体发生牙髓炎(0．25％)，10个修复体有食物嵌塞，24个修复体色调、彩度、明度出现偏差。均未见牙颈部继发龋，松动脱落现象。结论 选择适合的基牙，采用正确的备牙方式，合理的颈缘肩台设计，准确的邻接关系，细致的比色与调He，及时制作暂时冠，能使金属烤瓷修复体取得满意的临床效果。     

金属有机化合物在光电磁材料中的应用

本文综述了金属有机化合物在光电磁材料中的应用.     

碱金属氧化物稳定性的讨论

从热力学角度对碱金属的各类氧化物的稳定性进行了讨论。     

碱金属原子光谱精细结构

用半经典方法推得碱金属原子价电子自旋一轨道相互作用能公式、双层能级间隔公式等。从理论计算可知电偶极和电四极极化所引起的精细结构裂距很小。对n=13、l=5的量子态理论值与实验值基本相符。     

金属拱型波纹屋盖加强后受力性能研究

建立了加强后的金属拱型波纹屋盖模型,利用ANSYS有限元分析软件对加强后的波纹拱进行了荷载作用下几何非线性有限元分析,并与原波纹拱进行了变形与应力的比较。计算结果表明,加强后的波纹拱对约束结构位移变形有较好的效果,且提高了结构的承载能力,这一结论为该结构进行抗风、抗雪等设计提供了有益参考。     

CMOS反相器电压传输特性的分析和仿真

利用CMOS模拟电路理论,详细分析了CMOS反相器的大信号传输特性和小信号传输特性,并且给出了相应的MatLab和Pspice仿真结果.