Analysis of solute distribution in dendrites of carbon steel with δ/γ transformation during solidification

Solute distribution in dendrites during solidification of carbon steel was analyzed by unidirectional solidification experiments and mathematical analysis. The characteristic of the mathematical analysis is that diffusion of solutes in solid and redistribution of solutes at solid/liquid andδ/γ interfaces are taken into consideration. Based on the observed and calculated results, it was found that phosphorus was redistributed fromγ-phase toδ-phase, and that manganese was slightly redistributed fromδ-phase toγ-phase. Therefore the concentrated region of phosphorus can be separated from that of manganese duringδ/γ transformation in the case of slow cooling. Moreover, it was concluded that rapid diffusion inδ-phase and the redistribution duringδ/γ transformation played an important role in the variation of the interdendritic concentrations of solutes with lower carbon concentration.     

An investigation into the relationship between processing,structure and properties for high-modulus PBO fibres: part 3: analysis of fibre microstructure using transmission electron microscopy

A detailed morphological study of the microstructure of poly(p-phenylene benzobisoxazole) (PBO) fibres (HM and HM+) and a polypyridobisimidazole (PIPD) (HT) fibre has been undertaken using transmission electron microscopy. Both PBO and PIPD fibres are composed of rigid-rod polymers having p-phenylene rings in the molecular backbone and show high modulus (280–360 GPa) and high strength (4–6 GPa). It is found that the PBO HM+ fibre has the highest degree of molecular orientation of the three fibres and the longest crystal length along the fibre axis, while the PIPD fibre shows a lower degree of orientation and a shorter crystal length than the PBO fibres. To understand the effect of crystalline size and fine structure of the fibres upon mechanical properties, dark-field and high-resolution lattice images were obtained and analysed in detail.     

苏州多层住宅建筑生命周期评价

依据美国开发的BEES软件,选择张家港当地某一栋具体的多层住宅建筑(6层,每层大约750 m2)进行了生命周期评价.把建筑的全生命周期范围确定为建材准备阶段(包括原材科开采、运输、原材料加工等)、建造阶段、运行阶段(运行70年)、拆毁阶段和建筑垃圾处理阶段.依据确定的范围进行了清单分析.根据建筑的结构形式,计算得到各种建材的需求量和建造、运行、拆毁、建筑垃圾处理时的各种输入输出,以统一的功能单位(一栋建筑)合并各种输入输出数据,得到总的数据清单.采用BEES分类表征方法进行影响评价.根据我国的具体情况确定环境影响因子和类别(酸雨、全球变暖、资源枯竭等),将不同的环境影响因子分配到一个或多个环境影响类别中,再根据具体情况确定各指标的权重系数进行加权,得到综合的评价结果.找出了建筑物全生命周期阶段中产生环境影响最大的阶段,即运行阶段.     

Emulsion Stabilization by Maillard-type Covalent Complex of Plasma Protein with Galactomannan

Plasma protein was conjugated with galactomannan (GM) in a controlled dry state at 60°C and 79% relative humidity. The covalent attachment of GM to plasma protein was confirmed by SDS-PAGE and gel chromatography. Emulsifying activity of plasma protein-GM complex was 1.4 times and the emulsion stability of the complex was more than 10 times higher than those of plasma protein. In acidic (pH 3) and salt (0.2M NaCl) systems, the complex showed much more effective emulsifying properties than did commercial emulsifiers. Emulsifying properties of the complex were retained after preheating at 80°C for 30 min. Plasma protein-GM complex prepared by Maillard reaction during heating in a dry state could be used for heat-processed foods as a protein emulsifier.     

模拟流体中真核状态鞭毛运动和纤毛运动的放大推进机构

由于大部分的生物体都具有相对的自发性、功能性和有效率性，模仿生物体动作的机械研究在工程领域是非常重要的。根据这个观点，我们研究了一种基于水中微生物动作的微型推进机构。     

Determination of Foaming Properties of Proteins by Conductivity Measurements

A new method was established to estimate the foaming properties of proteins from the conductivity of foams using a simple apparatus that consisted of a glass column with the conductivity cell. A close correlation was observed between the initial conductivity of foams and the foam volumes of heat-denatured ovalbumins or 11 native proteins, suggesting that the initial conductivity of foams can be used as a measure of foaming power. In addition, a close correlation was obtained between the foam stability determined from changes in the conductivity and foam volume with time of heat-denatured ovalbumins or 11 native proteins, suggesting that foam stability also can be estimated from changes in the conductivity of foams. The advantages of the conductivity measurements are to determine the foaming properties more simply and accurately than the currently used methods.     

循环频率对SiCw／6061Al复合材料高温循环蠕变的影响

在测试应力范围内，SiCW／6061Al复合材料在196℃显示循环蠕变加速而在350℃显示循环蠕变减速在0～0.5Hz范围内，随着频率的增加，温度较低时循环蠕变应力指数增加而激活能降低，温度较高时应力指数与激活能同时增加当频率增加到1Hz时则偏离上述趋势     

Low Temperature Phase Transition in C70 and Solvation Effects

The heat capacity of C₇₀ has been measured by adiabatic calorimetry between 14 and 320 K. The orientational phase transition is observed as a broad hump in the heat capacity curve, which is strongly influenced by small amount of solvent remaining in the sample.