高层建筑用钢的发展

近年来，我国各大城市高层建筑发展迅猛，为充分利用有限的土地资源、发展钢结构建筑、急需大量建筑材，为此本文重点好国内外建筑用钢的发展，指出了高强度、高性能、大型化、功能化是建筑用钢发展的主要方向。     

New measurement of particle size distribution by a buoyancy weighing-bar method

The rates which particles from JIS Test Powders 1, Class 2 (silica sand), Class 3 (silica sand), Class 16 (calcium carbonate, heavy), and JIS Test Powder 2, Class GBM-20 (barium titanate glass) settled out of homogenous suspensions were determined using the principles of the buoyancy weighing-bar method as well as a sedimentation balance. Samples were standardized by Japanese Industrial Standard, and the dispersing agent was NaPP or NaHMP, while the viscosity improver was a starch syrup solution. Although constructing a handmade sedimentation balance is difficult, developing a handmade weighing tool capable of measuring particle size distribution is easy. Herein three weighing-bars, which were composed of aluminum, stainless steel, and copper, were used to measure the particle size distribution. However, an aluminum slit-cylinder occasionally replaced the weighing-bars. The weighing data obtained via an analytical balance were controlled by connecting the balance to a personal computer with an RS-232C interface, and the determined particle size agreed well with the data obtained by Andreasen analyses and the sedimentation balance.     

Pilot scale isolation of proteins from field peas (Pisum sativum L.) for use as food ingredients

Summary The protein and starch fractions of field pea ( Pisum sativum L.) are potentially a source of novel ingredients for food processing. As part of research to elucidate the functional properties of field pea proteins, the pilot scale extraction of proteins has been undertaken. Two different approaches have been used and the recoveries of protein compared. The first involved extraction with a salt solution followed by decanting and clarification to remove solids. The solution was then further concentrated and salt removed by ultrafiltration and diafiltration. The second procedure was based upon alkaline extraction followed by decanting and recovery by isoelectric precipitation and neutralisation. Both spray drying and freeze drying methods were employed. The protein isolates have been compared and characterised with respect to solubility, chemical composition and to electrophoretic patterns. Overall, the proteins extracted with salt exhibited better physical properties than proteins extracted with alkali, in terms of colour and particle size. The solubilities showed little variation and the electrophoretic patterns were similar. Freeze drying resulted in isolates with darker colour compared with spray drying.     

Densification of rare-earth (Lu, Gd, Nd)-doped alumina nanopowders obtained by a sol-gel route under seeding

Rare-earth (RE: Lu, Gd, Nd, 0.10 mol%)-doped alumina nanopowders were prepared by a new sol-gel route using polyhydroxoaluminum (PHA) and RECl₃ solutions under α-alumina (∼ 75 nm) seeding. Among the rare-earth dopants studied, Lu yields the most suitable nanopowders for low-temperature densification. The 0.10 mol% Lu-doped nanopowders, which were obtained at a calcination temperature of 900 °C under 5 mass% α-alumina seeding, consisted of ∼ 80-nm α-alumina particles and γ-alumina nanoparticles. Using these Lu-doped alumina nanopowders, fully densified alumina ceramics with a uniform microstructure composed of fine grains with an average size of 0.61 μm could be obtained at 1400 °C by pressureless sintering. Clearly, the Lu-doped nanopowders obtained here represent a viable option for fabricating dense, finer-grained alumina ceramics because an undoped sample with 5 mass% seeds gave a microstructure with an average grain size of 1.78 μm at 1400 °C.     

Characterization of cross-linked polyampholytic gelatin hydrogels through the rubber elasticity and thermodynamic swelling theories

A new approach is proposed to characterize polyampholytic gelatin hydrogels, cross-linked covalently with glutaraldehyde. An experimental methodology involving simple mechanical extension and compression and equilibrium swelling tests is developed to estimate relevant microstructural parameters and electrokinetic properties of this type of hydrogel, for different cross-linker to gelatin mass ratios. The polyampholytic cross-linked matrices are studied here in the framework of the rubber elasticity and thermodynamic swelling theories. The main purposes of this work are the estimations of average mesh size and toughness of the swollen hydrogels, and the determination of the feasibility of polyion complexation between cross-linked gelatin chains and bioactive macromolecules to be delivered through hydrogel biodegradation.     

含金多金属混合矿选矿试验研究

通过对洋鸡山金矿含金多金属混合矿的两个选矿工艺流程的研究及分析比较，铜优选浮选－－硫精矿焙砂氰化－－尾矿全泥氰化工艺流程比浮选－－氰化－－浮选工艺流程优越，技术可行，经济合理。     

稳盐对扁平卤化银微晶增感中心大小和分布的影响

稳盐对扁平卤化银微晶增感中心大小和分布的影响＊胡勇军王荣琴彭必先＊＊（中国科学院感光化学研究所，北京１００１０１）关键词Ｔ－颗粒，增感中心大小分布，电镜法，稳盐５－甲基－７－羟基－１，３，４三氮吲哚嗪（简称稳盐ＴＡＩ）作为乳剂制备过程的有机稳定剂，...     

高温超导V—I特性曲线变电流递增步长计算机采集系统

建立一套可变电流递增步长高温超导“V-I”特性曲线计算机采集5系统，可实现对超导样品进行自动变脉冲电流递增步长测试及方便迅速地对所测样品的数据进行分析处理，且提供了测试过程的实时显示与控制，同时软件界面友好，测试过程操作简单明了，有利于高温超导材料临界电流值Ic与国际研究结果的对比。     

调节聚苯乙烯树脂粒度分布的研究

研究了悬浮法聚苯乙烯粒度分布的两种调节方法：改变分散剂用量和改变反应初期分散相粘度。结果表明，分散剂用量增加，树脂粒径减小；分散相粘度增大，树脂粒径增大。     

1.6t树脂砂惯性振动紧实台的设计

根据试验结果，确定了惯性振动紧实台的工作参数，对其结构进行了改进设计； 设计的振动紧实台满足了砂型紧实度大于１０ ％ ，砂箱不跑偏、冷铁和活块不移位等要求。