Characteristics of Milk Powders Produced by Spray Freeze Drying

Skim and whole milk powders were manufactured at lab scale by spray freeze drying (SFD), using liquid nitrogen as the cryogen. The polydispersity of droplet/particle sizes was limited using an encapsulator nozzle to atomize the feed. Particle morphology was examined using a scanning electron microscope. Samples were compared with equivalent spray-dried powders in tests of wettability and dissolution in water. The spray freeze-dried powders were found to be highly porous, with a uniform structure of pores throughout the entire particles. When tested in water, SFD skim milk powders wetted roughly three times as fast as industrially spray-dried agglomerated skim milk powders and were observed to dissolve rapidly by breaking down into smaller particles.     

籼米淀粉超微粉体的制备及其性质

研究了籼米淀粉超微粉体的一种新的制备方法 ,通过正交实验确定了酶处理淀粉的最佳条件 ,考察了淀粉的溶解度和膨润力。结果表明 ,酶处理淀粉的最佳工艺参数为 :水解温度４５℃ ,时间为２５ｈ ,酶用量为水解淀粉的４５%。随着粒径的减小 ,淀粉的溶解度增大 ,膨润力下降。     

The Region 1 & 3 Broadcasting‐Satellite Service Plan after WRC‐03

The 1977 Broadcasting‐Satellite Service (BSS) Plan for Region 1 & 3 had been widely acknowledged to be out‐of‐date by the late 1980s. Development of digital modulation in the early 1990s provided an opportunity to update the technical provisions of the Plan to make it more economically viable. After a decade of work and three World Radiocommunication Conferences (WRCs), the revision of Region 1 & 3 BSS Plan was finally completed in 2003. The new Plan increased channel assignments from 5 to 10 analog‐equivalent channels for each country in Region 1, and from 4 to 12 channels for each country in Region 3. Yet, despite the increase in capacity, the new Plan is surprisingly similar to the original one in terms of the technical parameters. It is still based on national coverage, and the channel plan, orbital location, orbital spacing, and polarization are also the same. As a result, the new Plan is no more economically viable to implement than the old. To create economically viable BSS systems would most likely require modifications to the assignment in the Plan. Yet, modification procedures were made more difficult to apply after replanning. Less future implementation of BSS networks than would otherwise have occurred can be expected, and an inefficient usage of these frequency bands will likely result. On the other hand, less implemented systems will mean more capacity set aside for future use. This is important for countries that currently do not have satellite operations. In the end, BSS replanning reflects the eternal conflict between efficient usage and guaranteed future access. Copyright © 2005 John Wiley & Sons, Ltd.     

化学还原法制备纳米铜粉的研究

本文采用KBH4在液相中化学还原CuSO4,并加入KOH和络合剂EDTA ,制得了纳米级的纯净的铜粉 ,通过调整反应物的浓度 ,可以消除Cu2 O等杂质。制备的纳米铜粉还存在一定程度的团聚 ,需试验加入分散剂来改善。     

高合金钢铸造用涂料的试制与开发

介绍了炉爪用合金钢1Cr25Ni20Si2Re,导板用合金钢2Cr32Ni5采用串箱铸造过程中，有关镁砂粉涂料和石英粉涂料的试制。结果表明：镁砂粉涂料为不透气涂料，不太适用，而合理配方的石英粉涂料使用性能良好。     

超细粉碎技术现状及发展趋势

综述了国内外超细粉碎技术及设备的现状、进展,指出了其发展趋势,从工作原理、结构特点等方面详细介绍了超细粉碎典型设备,同时又指出了近年来国内外在此领域中的新进展,基于现存问题指出了今后超细粉碎研究的方向。     

气流式加速度传感器的敏感机理

介绍了在研制气流式加速度传感器过程中，为对气流式加速度传感器进行建模，作者对气流式加速度传感器的工作机理进行了理论性探讨。在分析过程中以流体力学、传热学和惯性理论为基础并结合实验结果，建立了适合于气流式加速度传感器的气体运动方程和能量方程。同时还讨论了热线测量加速度的方法及根据实验分析了输入加速度对腔体内温度及传感器输出电压的影响，从而为进一步研究一系列气流式传感器的工作机理提供了方法。     

高性能各向异性Sm2Fe17Nx磁粉的制备

本文研究了高性能各向异性Ｓｍ２Ｆｅ１７Ｎｘ磁粉的制备工艺路线与工艺参数。优化了制备与工艺参数。已制备出磁性能达到：Ｂｒ＝１．３９Ｔ，Ｈｃｉ＝８５０ＫＡ／ｍ和（ＢＨ）ｍ＝２３６ＫＪ／ｍ＾３的各向异性Ｓｍ２Ｆｅ１７Ｎ２．８８磁粉，该磁粉的各向异性场ＨＡ达到２０Ｔ。     

Preparation and Properties of Sintering Additives Coated Si3N4 from Heterogeneous Nucleation Processing

The sintering additives such as Al2O3 and /or Y2O3 were coated on the surfaces of Si3N4 particles via heterogeneous nucleation processing using a buffered pH solution as the precipitation reagent .They nucleated and grew only on the surfaces of Si3N4 and did not form sol particles in solution by TEM observation .The isoelectric point(IEP) of coated Si3N4 was different from that of as-received Si3N4.The IEP of Al(OH)3-coated Si3N4 occurred at pH8.4, which is close to that of alumina .When Al(OH)3-coated Si3N4 particles were coated with Y(OH)3,the IEP of coated Si3N4 powder shifted from pH8.4 to pH9.2 ,similar to that of yttria.In addition ,the rheological data showed that Al2O3 and /or Y2O3 coated Si3N4 suspension is nearly Newtonian and that added Si3N4 suspension shows a shear rate thinning behavior.     

Li2O在保护渣中的作用

采用在不同玻璃性的两种基渣中加入Ｌｉ２Ｏ为研究Ｌｉ２Ｏ对保护渣粘度，熔化温度及玻璃性能的影响，并对Ｌｉ２Ｏ改善保护渣玻璃性的机理进行了探讨，提出了寻找高速连铸保护渣中Ｌｉ２Ｏ的代用物的一种方法。