Mg含量对过共晶铝硅合金组织和性能的影响

研究了不同的Mg含量对过共晶铝硅合金组织和性能的影响．利用扫描电镜和金相显微镜观察了过共晶铝硅合金在Mg含量不同时和热处理前后的金相组织变化，利用XRD和EDS分析了合金中不同金相组织的相，利用硬度计测试了合金的布氏硬度和不同相的维度硬度．实验结果表明：在过共晶铝硅合金中，不同的Mg含量在过共晶铝硅合金中生成不同形态的Mg：Si；热处理使板条状的共晶硅细化成点状，汉字状的Mg2Si细化变为球状；Mg含量在1％-5％的范围内，过共晶铝硅合金的硬度随Mg的含量增加而增加，热处理可以显著提高合金的布氏硬度．     

纳米Fe2O3的制备及其对高氯酸铵催化性能的研究

以氯化铁和尿素为原料、亚油酸钠为分散剂,采用均匀沉淀法制备纳米Fe2O3。用XRD、FESEM对产物粒子的晶体结构、形貌和粒径大小进行表征;结果表明,制得的Fe2O3为α‐Fe203,呈球形、晶粒度在20nm～40nm范围内且分散性好。采用热重差热联用分析仪(TGA-DSC)研究纳米Fe2O3对高氯酸铵热分解的催化性能;结果表明,纳米Fe2O3对高氯酸铵热分解的催化性能明显优于微米Fe2O3。     

金属电极电还原CO2的研究进展

CO2电还原技术在降低"温室效应"、缓解能源危机及消除密闭环境的CO2等方面都有很重要的意义。综述了金属电极在水溶液、有机溶剂以及熔融体中电还原CO2的研究现况,包括各类金属在电还原CO2过程中所表现出的反应活性以及生成相应产物的反应机理;介绍了电极、温度、压力、电极电位和电解质等因素对金属电极电还原选择性及法拉第电流效率的影响;展望了CO2电还原的未来研究方向及应用前景。     

冷板车制冷机组隔振仿真研究

针对冷藏运输车的振动问题,基于二自由度振动分析理论建立了制冷机组的振动力学模型,并通过现状仿真和优化隔振效果仿真得到了冷板车制冷机组最优减振隔振方案.通过现状仿真得到了满载和空载工况下隔振器变形随时间变化的曲线以及机组与车体加速度的对比曲线,并给出了制冷机组取得较好隔振效果隔振器必须满足的频率和刚度范围.结果表明:制冷机组现有的隔振效果很差;通过优化隔振效果仿真得到了不同隔振器固有频率时车体和机组最大加速度的响应曲线以及隔振器最大变形曲线.     

电磁兼容技术在机车变流器布线中的应用

依据产品开发过程中电磁兼容技术的常用理论,结合国际上先进水平的大功率变流器电磁兼容技术的设计概念和工艺方式,就国产化铁路机车变流器中各种电缆的布线设计及工艺进行分析,总结出布线过程中减少电磁干扰的方法。     

COX-2蛋白表达与口腔鳞癌侵袭转移的关系

从COX-2的生物学特性，可知促进口腔鳞癌侵袭转移的机制为促进肿瘤新生血管的生成、刺激肿瘤细胞的增殖、抑制肿瘤细胞的凋亡、促进肿瘤的浸润和转移、抑制机体的免疫反应、参与前致癌物的活化。（可应用COX-2抑制剂防治肿瘤）     

Determination of anthropogenic CO2 in the North Atlantic Ocean using water mass ages and CO2 equilibrium chemistry

A new method to calculate the anthropogenic CO₂ (ΔDIC_ant) within the water column of the North Atlantic Ocean is presented. The method exploits the equilibrium chemistry of the carbonate system with reference to temperature, salinity and the partial pressure of atmospheric CO₂ (pCO_2,atm). ΔDIC_ant is calculated with reference to the ventilation ages of water masses derived from tracer data and to the time history of pCO_2,atm. The method is applied to data recorded during the WOCE program on the WHP A1/E transect in the North Atlantic Ocean, where we characterise six key water masses by their relationships of dissolved inorganic carbon (DIC) and apparent oxygen utilisation (AOU). The error in determining ΔDIC_ant is reduced significantly by minimising the number of values referred to, especially by avoiding any use of remineralisation ratios of particulate organic matter. The distribution of ΔDIC_ant shows highest values of up to 45 μmol kg⁻¹ in the surface waters falling to 28–33 μmol kg⁻¹ in the Irminger Sea west of the Mid-Atlantic Ridge. The eastern basin is imprinted by older water masses revealing decreasing values down to 10 μmol kg⁻¹ ΔDIC_ant in the Antarctic Bottom Water. These findings indicate the penetration of the whole water column of the North Atlantic Ocean by anthropogenic CO₂.     

中国农业类上市企业运行效率的DEA分析

本文运用数据包络分析方法对我国12家农业类上市企业的运行效率进行评价,测算了各个农业企业的综合技术效率、纯技术效率和规模效率状况。研究表明：我国农业类上市企业总体效率偏低,两级分化严重,纯技术效率基本有效,规模效率较低,投入不足。     

The study of correlative factors to resistin and its regression equation in type 2 diabetes

Objective To study the changes of resistin and the relationship between resistin and other indexes in patients with type 2 diabetes mellitus. Methods Seventy patients with type 2 diabetics were chosen and divided into three groups according to weight index and 15 healthy persons were chosen as controls. ELISA was adopted to determine resistin concentration. Oxydase method was adopted to measure blood sugar. Radio immunoassay was used to measure insulin level. Results Resistin concentration of patient groups r(23.06±9.34)μg/L ] was significantly higher than that of control group [( 9. 89±4. 47) μg/L, P<0. 01 ]. Resistin was positively related to body mass index (r = 0.4 467) and fat distribution (r= 0. 3 314, P<0.01). Resistin was also positively correlated to the area under the curve of sugar tolerance (r=0. 7 063, P<0. 01), negatively related to the insulin resistance index (r=-0. 4 154, P<0.01), but not related to area under the curve of synchronous insulin release (P>0. 05). And a formula was obtainted : Resistin=- 15. 869 0. 339×GAUC 0.790×BMI. Conclusion The level of reslstin in type 2 diabetics is higher. And reslstin is related to other factors. This formula is of great significance for clinical study of diabetic's disor- ders.     

一种基于ISDN 2B+D接口的同步研究

分析了在ISDN用户环路中2B＋D接口的同步问题、各种同步方式，以及关键的技术，结合MITEL公司的基本速率芯片搭建出了2B＋D的数字接口，为数字调度台提供了方便可靠的数据接口，并且已成为地应用现场中。