Determination of 90Sr, 238Pu, 239,240Pu, 241Pu, and 241Am in soils of chernobyl region using various sample preparation techniques

Radiochemical analysis is made of soddy-podzolic sandy and peaty gley soils collected from the Chernobyl zone. Radionuclides were separated by extraction chromatography or ion exchange, and then determined using an α-ray spectrometer and liquid scintillation and proportional gas counters. Leaching from the preliminarily calcined sample with 8 M HNO₃ does not ensure 100% recovery of radionuclides from peaty gley soil.     

嵌入式超长指令语音压缩处理器的VLSI实现

介绍了一款语音压缩专用处理器的设计思路，使用嵌入式FLASH超长指令字系统有效的提高了芯片的处理能力，同时将增强型算术逻辑单元、乘法器、乘累加器结合在一起，在改进的哈佛体系结构上实现了微控制器与DSP的单核设计。使用存储器操作指示寄存器、分层寄存器组，能够简化子程序调用方式。该微处理器采用0．25μm CMOS工艺实现，芯片面积为25mm^2。仿真结果表明，在20MHz工作频率下，芯片处理能力与50MIPS的通用DSP相当，同时能够保持原有编码质量。该处理器能够实现多种类型的语音压缩算法，可以达到对语音算法的高保密性、低复杂度、易开发性。     

中日西文输入系统的设计

本文围绕中日西文输入系统的设计，主要论述了规范中日西文机内码的客观依据，并给出了在汉字信息处理系统中挂接一种新的输入模式的基本方法[1]。     

岭澳核电站2#机组振动问题分析及处理

总结了岭澳核电站2#机组商业运行后首次大修的振动问题及动平衡情况,并对出现的动静摩擦作了分析.     

In Vitro Characterizations of PLLA/β-TCP Porous Matrix Materials and RMSC-PLLA-β-TCP Composite Scaffolds

To develop a novel degradable poly (L-lactic acid)/β-tricalcium phosphate (PLLA/β-TCP) bioactive materials for bone tissue engineering, β-TCP powder was produced by a new wet process. Porous scaffolds were prepared by three steps, I.e. Solvent casting, compression molding and leaching stage. Factors influencing the compressive strength and the degradation behavior of the porous scaffold, e.g. Weight fraction of pore forming agent-sodium chloride (NaCl), weight ratio of PLLA: β-TCP, the particle size ofβ-TCP and the porosity, were discussed in details. Rat marrow stromal cells (RMSC) were incorporated into the composite by tissue engineering approach. Biological and osteogenesis potential of the composite scaffold were determined with MTT assay, alkaline phosphatase (ALP) activity and bone osteocalcin (OCN) content evaluation. Results show that PLLA/β-TCP bioactive porous scaffold has good mechanical and pore structure with adjustable compressive strength needed for surgery. RMSCs seeding on porous PLLA/β-TCP composite behaves good seeding efficacy, biocompatibility and osteoinductive potential. Osteoprogenitor cells could well penetrate into the material matrix and begin cell proliferation and osteogenic differentiation. Osseous matrix could be formed on the surface of the composite after culturing in vitro. It is expected that the PLLA/β-TCP porous composites are promising scaffolds for bone tissue engineering in prosthesis surgery.     

公共服务合作供给网络建构

伴随着经济社会的发展,公共服务由传统政府垄断供给转向市场化和社会化的多元供给。然而,由于多元供给行动者之间是在竞争制度框架下的"各有所图",市场化、社会化的供给方案在丰富和提高公共服务种类和质量的同时,必然陷入"市场失灵"和"志愿失灵"的桎梏。只有通过服务型政府建设来引导公共服务供给多元行动者的健康成长,在平等和信任的基础上,实现信息资源的共享,促进社会走向成熟自治,才能形成多元行动者合作供给的制度框架,并为建构起新的公共服务供给模式提供可行的理论依据。     

System analysis of the efficiency and competitiveness of chroming technologies

The scientifically based selection of efficient chemical technologies is related to the integrated assessment of indicators of their energy and resource efficiency and environmental safety, as well as indicators of the quality of products. The authors conducted systematic analysis of the efficiency and competitiveness of two electrochemical technologies of chroming from the solutions based on chromium salts of different valences. The strengths and weaknesses of each technology have been defined using the methodology of SWOT analysis, and the defined qualitative indicators of the efficiency of technologies have been determined using the methods of nonparametric statistics.     

Microstructure and mechanical properties of Sn–Zn–Bi–Cr lead-free solder

In this paper, the effect of trace addition of Cr on the mechanical properties and reliability on Sn–8Zn–3Bi solder alloys was investigated. It has been demonstrated that the microstructure of solder alloys was refined after doping traces of Cr. The elongation reaches up to 40.63% after doping 0.1% Cr; and the fracture mechanism converts from quasi-cleavage fracture into ductile fracture. With aging time of 0, 4, 9 and 16 days, mechanical property of Sn–8Zn–3Bi–0.3Cr alloy was improved slightly. It was found that the Sn–Zn–Cr phase was increased and Zn in alloy was consumed after aging, so that the amount of primary Zn phase was reduced and microstructure was improved.