铝合金高速船船体建造工艺

简述了ＬＦ１５和ＬＦ１６两种新型船用耐蚀可焊铝合金及其配套焊接材料在实船建造中的应用情况。阐述了铝合金全焊结构船体建造的关键技术及我国铝船体建造的３种方法     

简易高性能纳秒脉冲发生器

为了实现电子散射飞行时间谱仪电子束的脉冲化及产生时一幅变换器的启动或停止信号。我们利用开关晶体管的雪崩特性研制了一个性能好，成本低的纳秒脉冲发生器。该发生器输出上升时间好于Ｉｎｓ，幅度达１０Ｖ的负尖脉冲，用作时一幅变换器的启动或停止信号；也输出上升时间约３ｎｓ，幅度５－３０Ｖ连续可调和宽度５－２３０ｎｓ可调的正脉冲，用作电子束脉冲化的调制信号，脉冲重复率为１５０×１０＾３ｓ＾－１。它可广泛用于类似     

高纯锗探测器的快定时性能及其应用

为了将高纯锗（ＨＰＧｅ）探测器用于快定时的物理实验中，本实验研究厂影响高纯锗探测器定时谱仪时间性能的各种因素，找出了获得谱仪最小时间分辨的各种最佳参数。并建立了分辨时间为４．１９ｎｓ，能量分辨率为２０ｋｅＶ，微分非线性好于±２．０％，计效率可承受１２０×１０￣３ｓ￣（－１）的时间微分扰动角关联谱仪。利用此谱仪，以￣（２０４）Ｂｉ为探针核，研究了Ｂｉ系高温超导的微观机理，取得了较好的结果。     

回火处理对高碳冷拔钢丝强度和塑性的影响

研究了６５钢冷拔钢丝在５００℃不同时间回火时的抗拉强度和延伸率的变化。试验结果发现，在回火初期，抗拉强度首先增长，然后随口火时间的延长连续降低，而延伸率始终在增长，增长速度是先快后慢。这种行为可归因于第一内应力的消除和ε－碳化物在形变铁素体中的析出以及后来再结晶的发生。     

Thermography of aged contacts of high voltage equipment

New developments in diagnostic tools and systems are necessary for a reliable and economic evaluation of the condition of equipment in power systems. In a research project a tool for the condition of contacts of centre break disconnector, which is used under normal operation by the aid of a thermography measurement system, has been developed. In this paper, an overview about the laboratory investigation of the temperature load behaviour and the environmental influence on-site for new and aged disconnector contacts are given. A condition evaluation tool for contacts, which was the aim of the project, has been created. The basic method for the evaluation is presented, and also two additional easements for a fast identification of suspect contacts are presented. With this evaluation tool and the usage of a thermography based measuring system, a condition based maintenance strategy can be applied, whereby an early detection of damages is possible and so power quality and reliability increase.      

地理环境与先秦南北饮食文化

先秦时期是我国饮食文化的形成时期，受地理环境的强烈影响，逐渐形成了以秦岭-淮河一线为界的南北两个主要的饮食文化区域：黄河中下游地区为中心的北方饮食文化区，是以旱地粮食作物黍、稷、粟等为主食，陆地动物为辅食，烧、烤、炸为主要烹饪方法的北方饮食风味；长江中下游地区为中心的南方饮食文化区，是以水田粮食作物稻米为主食，陆地动物和水产动植物为辅食，蒸、炖、煎为主要烹饪方法的南方饮食风味。     

A New Variable Diffusion Drying Model for the Second Falling Rate Period of Paddy Dried in a Rapid Bin Dryer

The objectives of this article is to propose a new drying model for the second falling rate period known as the variable diffusion controlled period that follows after the first falling rate period and to propose a new method to determine the second critical moisture content that separates these two periods. Experimental work on paddy drying at minimum fluidization velocity was carried out in a rapid bin dryer. The effects of operating temperatures (60-120°C) and bed depths (2-6 cm) on the paddy drying characteristics were investigated. It was found that the normalized drying rate of paddy was proportional to the normalized moisture content in the first falling rate period but in the second falling rate period, the normalized drying rate of the material varies exponentially with the normalized moisture content. The different relationship between the normalized drying rate and the normalized moisture content in the first and second falling rate periods indicate that two different mechanism of moisture transport are at work. The new exponential model of the second falling rate period and the linear model of the first falling rate period were found to fit the experimental data very well. Derivation from variable diffusion equation shows that the linear model is the result of constant diffusion coefficient whereas the new exponential model is the result of linear diffusion coefficient. This also implies that the first falling rate period is a constant diffusion controlled period and the second falling rate period is a variable diffusion controlled period. In addition, drying kinetics data of a drying process that fits the exponential model over a very slow drying period will show that the drying process is under the effect of a linear diffusion coefficient. It was also found that the proposed new method to determine the second critical moisture content that distinguishes between the first and second falling rate periods by using a sudden change in the value of the drying rate gradient to a much lower value at that point is more rigorous and yet simpler than the method of determining the specific location of the receding drying boundary since it is based on the behavior of the actual drying kinetic data.     

An Electronic Approach to Materials Design

A molecular orbital approach to materials design has recently made great progress. This approach is based on the electronic structure calculations by the DV-Xα cluster method. In this paper recent progress in this approachis reviewed. In particular     

High temperature transport kinetics in heteroepitaxial LaFeO3 thin films

Heteroepitaxial LaFeO₃(1 1 0) thin films with a thickness of 150 nm were grown on LaAlO₃(0 0 1) by reactive sputtering in an inverted cylindrical magnetron geometry. Equilibrium conductivity was measured as a function of partial pressure of oxygen at T=1000 °C, and logσ plotted vs. logP(O₂) showed a minimum in conductivity for P(O₂)=10⁻¹¹ atm and a linear response between 10⁻¹⁰ and 1 atm. This linear response makes thin films of LaFeO₃ a promising material for oxygen sensor applications. We have also measured the time response of the film conductivity upon an abrupt change in the partial pressure of ambient oxygen from 10⁻² to 10⁻³ atm, which was determined at 60 s for T=700 °C and <3.5 s at T=1000 °C.     

高放废液中^147Pm的测定

建立了高放废液中~(147)Pm的测定方法。用HDEHP萃取稀土,再用HDEHP萃淋树脂柱分离AM和稀土。然后用高效液相色谱法将~(147)Pm从Eu、Ce等其它稀土中分离出来,用液体闪烁法测量~(147)Pm的放射性活度。