松华坝水源地坡面水土保持林对水沙关系影响及其贮水能力分析

通过对松华坝水源地径流与泥沙变化规律分析。利用松华坝水源保护区1982-2010年的LANDSAT TM遥感图像,采用ENVI遥感图像处理方法估算出该流域多年水土保持林地面积变化情况,并按不同坡度进行分类。通过双方数据的对比分析,得到径流含沙量与水土保持林覆盖度呈指数关系,水土保持林覆盖度越高,径流含沙量越低。本文采用扣除负功能法对水土保持林计算森林实际贮水能力,由此得出松华坝地区水土保持林平均年实际贮水量为1.1344亿m3。     

商业银行风险资本管理的新思考

经济资本是商业银行计量风险、信贷决策、贷款定价、市场拓展、预算计划、衡量业绩的标尺,它是商业银行全面风险管理体系建设的关键环节。商业银行通过经济资本,可以真实地反映自身所面临的风险状况,有效强化风险管理,适时调整风险管理重点,切实把好商业银行风险管理关。     

Preparation of yttria nanopowders for use in transparent ceramics by dry ball-milling technique

To evaluate the effectiveness of dry ball-milling, yttria powders were ball-milled, and the optimal sample was spark plasma sintered to fabricated transparent yttria ceramics. The characterization of the powders and pellets were analyzed using XRD, FESEM, UV/VIS/NIR and FTIR spectrometer throughout the whole experimental process. The results indicated that ball-milling can significantly decrease yttria particle size and enhance the specifice surface area. The best duration is 20 h ball-milling with average particle size and specifice surface area of 64 nm and 20.4 m²/g, respectively. Transparent yttria ceramic was made up of grains in the size range of approximately 0.67 μm and the relative density was 99.8%. The in-line transmittance of the SPS-sintered yttria ceramic (2.5 mm thick) reached 83% in the infrared region, which is very close to the theoretical value of yttria.     

水下航行器燃气涡轮机叶轮模态分析

为了避免水下航行器燃气涡轮机在工作时发生共振,在合理的假设条件下建立了燃气涡轮机叶轮的有限元模型,利用有限元分析软件ANSYS的循环对称方法对其进行了模态分析,并对前12阶振型进行了讨论,分析了叶轮转速和工作温度对叶轮模态的影响,所得结论符合工程实际规律,对水下航行器燃气涡轮机的安全使用、结构设计和动力学分析具有重要的参考价值。     

考虑支护结构变形的基坑土压力计算

针对基坑土压力计算存在的不足,基于朗肯土压力理论,建立了考虑支护结构与土体相互作用的土压力计算模型。结合温克尔假定,推导出考虑基坑支护结构变形的非极限主动、被动土压力计算公式。同时,对支挡式基坑支护结构的变形分布进行了简化,提出了适用于支挡式基坑支护结构设计阶段的土压力简化计算方法。     

球形纳米银粉的制备与微结构研究

以硝酸银为原料,以对苯二酚C6H4(OH)2作为还原剂,添加链烷醇胺A作分散剂,液相化学还原法制备出分散性良好的球形纳米银粉。用激光粒度分布仪测试银粉的粒度分布与平均粒径,用透射电子显微镜(TEM)分析银粉的形貌、粒径和团聚状态,用多晶X射线衍射仪(XRD)检测粉体的晶相。实验结果表明:制备的纳米银粉为面心立方晶体结构,呈现规则球形,并且具有狭窄的粒度分布,其平均粒径约为100 nm,振实密度约为4.0 g/cm3。     

Statistical Analysis of the Hole Primary Halo in Dachang Sn Zn Polymetallic Mining Area of Guangxi

The complexity and diversity of Ore forming is the commonness, of which the difficulty is the evolutional characteristics of geochemical elements. The metallogetic process can be speculated and get useful and microcosmic message for next exploration. In this paper, the research of cluster analysis and factor analysis of the hole primary halo in Dachang SnZn polymetallic mining area in Guangxi reveal that metallogenic process is very complex and superposed by mineralization .It is considered that the enrichment of Zn,Sn superposed anaphase. By sulphide polymetallic, Au is very independency and that Sb,Pb,Ag and Cu are proximal indicator elements for exploring Zn,Sn in the mine.     

Improved Compaction in Multilayer Capacitor Fabrication

The most common defects found in multi-layer ceramic capacitors are derived from residual porosity formed when solvents and binders are released from a ceramic green body. Without a well-controlled compaction technique, defects between sheets in the stacked body are often present, leading to lamination problems. This paper suggests alternative approaches, using compaction applied before and/or after the process of binder burnout with the intention of reducing the number of stacking-generated defects and the volume of voids formed after binder burn-out. Barium titanate tapes and stacked multilayer electroded discs have been investigated and characterised by microstructural examination and density measurement. The resulting properties are described, and the behaviour of the multi-layers discussed in terms of the microstructure and processing procedures. It is shown that the porosity content of sintered samples compacted at 300 MPa is approximately half that of samples compacted at 30 MPa when both are sintered at 1300°C for 2 h. A further improvement of densification can be achieved by a postcompaction treatment after binder burn out.