理化检验样品中铅,铜测定的微波消化条件探讨

报道了利用微波消化检验样品的基本原理，并介绍了利用民用微波炉，聚四氟乙烯高压罐消化样品的操作方法及最佳消化条件。经微波消化的消化液。应用原子吸收法测定其中的铅和铜，并做了回收率实验。测定结果变异系数铜：２．０％－４．５％，铅：２．５％－３．８％。回收率铜９８．０％－９９．０％，铅：９６．０％－９９．５％。     

镁合金在高速列车上的应用与开发

作为现有最轻的金属材料的镁合金以其在轻量化方面的突出优点,在航天、航空和汽车制造业等领域获得了广泛的应用,但在现代铁道车辆中鲜有应用,特别是在高速列车领域中还是一片空白.本文通过对镁合金材料的特点、优势和在普通铁路客车中的应用现状分析,初步讨论镁合金在高速列车中的开发应用目标,技术攻关的方向和主要内容,最后归纳几点建议.     

Al,Cu含量对ZA合金性能影响的研究

研究了不同的Ａｌ、Ｃｕ含量对ＺＡ合金（即锌铝合金）力学性能的影响．结果表明，ＺＡ合金中的含Ａｌ量可在相当宽的范围内（２５％～４５％）变化，而其性能保持在σ＿ｂ≥４００ＭＰａ，δ≥６．９％。其中抗拉强度σ＿ｂ值随着含Ａｌ量的增加先提高后降低，在含Ａｌ量为Ａｌ＿４处出现峰值；而延伸率δ值则随着含Ａｌ量的增加逐渐降低。Ｃｕ的含量必须适当，在本研究条件下，ＺＡ合金中的最佳含Ｃｕ量为３％。     

16Mn钢解理断裂性质的局部方法分析

用断裂力学的局部方法对低合金钢16Mn的低温断裂韧性进行了分析和预测。结果表明,16Mn钢的材料常数σ_u约为2550MPa,m=16～18。由拉伸实验确定的这两个材料常数,可以看成16Mn钢的固有的解理性质,与温度无关。本文将无量钢系数C_m作为应变硬化指数H和温度的函数加以分析,并进一步给出了C_m值随m变化的趋势。本文表明,在分析金属材料的低温断裂性能时,局部方法简化了材料的特征描述,能评估带缺陷(含裂纹)结构的力学完整性。     

Cu-(0.5%~1.5%)Te合金组织和性能

采用真空感应炉制备出0.5%Te,1.0%Te,1.5%Te的Cu-Te合金,然后进行了锻造和拉拔工艺试验.通过金相显微镜观察了合金中第二相的分布情况,测试了拉拔试样退火前后的拉伸性能和电阻率.结果表明:Cu-Te合金中的第二相主要分布在晶界上;随着Te含量的增多,第二相的数量除了在晶界分布外,在晶内也有分布.1.0%Te和1.5%Te的Cu-Te合金易锻裂,只有0.5%Te可以锻造;0.5%Te锻造合金拉拔后第二相被拉长并沿拉伸方向呈纤维状分布;拉拔试样的抗拉强度远高于退火试样;退火略微降低Cu-Te合金的电阻率(2.57×10-8Ω.m),但仍高于美国Cu-Te合金(C14500)标准的电阻率(1.86×10-8Ω.m).     

离子镀奥氏体Fe-Mn基合金表面改性层耐蚀性研究

在奥氏体Fe-Mn基合金表面离子镀1Cr18NigTi不锈钢薄膜，改性后的Fe-Mn基合金在1mol／LNa2SO。溶液中的耐均匀腐蚀性能和在1％NaCl溶液中的抗点蚀能力均明显优于未改性Fe-Mn基合金，甚至略优于1Crl8Ni9Ti不锈钢．Fe—Mn基合金表面改性后的耐蚀性，主要取决于改性层的结构、成分和缺陷．     

Influence of the heavy fuel spill from the Prestige tanker wreckage in the overlying seawater column levels of copper, nickel and vanadium (NE Atlantic ocean)

The water column above the Prestige wreckage was sampled during two consecutive campaigns: Prestinaut (December 2002) two weeks after the tanker sunk and HidroPrestige0303 (March 2003) one month after the sealing of the main fuel leaks. Samples of the original cargo fuel and the emulsified fuel in the surface of the ocean were also collected. Analysis of the fuel indicated the release of 135 kg of Cu, 1700 kg of Ni and 5300 kg of V from the original fuel to the water column, remaining 35 kg of Cu, 3100 kg of Ni and 13,800 kg of V in the emulsified fuel. The metal partitioning between the water column and the emulsioned floating fuel, Cu > Ni ~ V, are in accordance with the stability index for the metal–nitrogen bond in metalloporphyrins. This release had an impact on dissolved trace metal concentrations in the water column. An increase on dissolved copper (2.8–4.7 nM) and nickel (2.2–8.0 nM) with respect to natural values (1–3 nM for Cu and 1.6–5 nM for Ni) was observed. Values for vanadium (28–35 nM) were in the range of pristine North Atlantic waters (30–36 nM). This contamination was especially observed in the upper water column (0–50 m), associated with the mixing of seawater with the fuel moving upwards, and in deep waters, where the residence time of fuel is higher. Future research in this field should focus on the environmental variables and the processes that control the release of contaminants from fuels for a better assessment of the contamination in oil-spill events.     

Empirical Study on Arbitrage Opportunities in China Copper Futures Market

Introduction Arbitrage opportunities attract considerable atten-tion of scholars in economics and finance. Modiglianiand Miller first performed no-arbitrage equilibriumanalysis in 1958[1]. Following their work, Black andScholes[2]deduced the option pricing model. Ross[3]and Cox[4]put forward arbitrage theory and risk neu-tral pricing method. Harrison and Kreps[5], and Har-rison and Pliska[6]proved that the no-arbitrage equi-librium system can be constructed by equivalent mar-tingale measur…     

铸造铝硅类合金宏观晶粒粗化规律的研究

研究了名硅类铸造合金的浇注温度化学成分、保温时间、回炉料加入量、变持处理遗传等因素对铝硅类铸合金宏观晶粒的影响，得出了一些对生产实际有意义的规律性结论。     

添加稀土元素对硬质合金物理机械性能和切削性能的影响

本文研究了稀土元素的添加种类和添加量对ＹＴ１５硬质合金物理机械性能和切削性能的影响。研究结果表明，添加稀土元素后硬质合金刀片的抗弯强度以及刀具耐用度等显著提高；添加Ｓｍ，Ｙ，ＳｍＰｒ效果较好，并且添加量存在一量佳范围，本文还对添加稀土元素后硬质合金的改机理作了探讨。