Development of laser welding technology for fully austenitic stainless steel

The radial stainless steel plates (RPs) used for Toroidal field (TF) coils in the International Thermonuclear Experimental Reactor (ITER) are 13 m long, 9 m wide and 10 cm thick, which are quite large. Even though they are very large structures, high manufacturing tolerances and high mechanical strength at 4 K are required. It is also required that each RP should be fabricated every three weeks. Therefore, the authors intend to develop efficient manufacturing methods for an ITER TF coil RP. Laser welding is then selected as a welding method for RP. Especially, the development of high technology laser welding is necessary to prevent hot cracking in the material used for the RP; namely, fully austenitic stainless steel with high nitrogen content. The authors carried out trial laser welding experiments aiming at its application to RP. As a result, it was effective to make the angle of back inclination of the weld head at a uniform welding speed. It also seemed that the sensitivity of hot cracking could be reduced by optimizing the chemical compositions of material used for RP. The base material and the welded joints satisfied mechanical properties in 4 K. The application of the laser welding technology to the fully austenitic stainless steel was therefore demonstrated.     

Separation and Recovery of Silver(I) Ions from Base Metal Ions by Thiourea- or Urea-Formaldehyde Chelating Resin

Abstract

In the present work, thiourea-formaldehyde (TF) and urea-formaldehyde (UF) chelating resins have been synthesized and they have been used in the adsorptions of Ag(I), Cu(II), and Zn(II) metal ions by batch and column methods. The effect of initial acidity of Ag(I) solution and the adsorption capacities of TF and UF resins by batch method and the separation of Ag(I) ions from Cu(II) and Zn(II) base metal ions by the column method were examined experimentally. The adsorption capacities of TF and UF resins were found as 58.14 and 47.39 mg Ag(I)/g by batch method and 30.7 and 4.66 mg Ag(I)/g, 0.80 and 0.121 mg Cu(II)/g, and under 0.002 mg Zn(II)/g by the column method, respectively. It was found that Ag(I) ions showed higher affinity towards TF resin than UF resin, compared with Cu(II) or Zn(II) ions, and Ag(I) could be separated more effectively by TF resin from Cu(II)and Zn(II) ions.     

用UASB-TF法处理某乳品厂废水

利用UASB-TF法处理某乳品厂废水,出水达到GB8978-1996中的Ⅰ级排放标准.该法处理乳品废水具有投资低、运行成本低、污染物去除率高、操作方便稳定的特点.在进水浓度1000 mgCOD/L时,出水浓度可以降到60-80 mgCOD/L,UASB的水力停留时间12h,TF体积负荷0.4kgCOD/(m3.d),水力停留时间4h,出水回用于冷冻机冷却水,直接运行成本0.30元/m3.     

纳米银研究和应用新进展

包括化学还原法、光学还原法、电化学法、溶胶-凝胶法和真空蒸镀等。简述了纳米银在抗菌材料和催化剂等方面的应用,指出了纳米银的制备过程中存在的问题和发展方向。     

用MOCVD方法制备ZnS：Mn交流薄膜电致发光显示器

用ＭＯＣＶＤ方法制备ＺｎＳ：Ｍｎ交流薄膜电致发光显示器赵丽娟,钟国柱,杨宝钧,郑陈玮,赵国璋（中国科学院长春物理研究所１３００２１）（中国科学院激发态物理开放实验室）Ｚｎ：ＭｎＡｌｔｅｒｎａｔｉｖｅＣｕｒｒｅｎｔＴｈｉｎＦｉｌｍＥｌｅｃｔｒｏｌｕｍｉ...     

藏文停用词选取与自动处理方法研究

停用词的处理是文本挖掘中一个关键的预处理步骤。该文结合现有停用词的处理技术,研究了基于统计的藏文停用词选取方法,通过实验分析了词项频率、文档频率、熵等方法的藏文停用词选用情况,提出了藏文虚词、特殊动词和自动处理方法相结合的藏文停用词选取方法。实验结果表明,该方法可以确定一个较合理的藏文停用词表。     

量化词语的领域特征

词作为最小的语义单位,同领域之间具有复杂的关系,特别是较为常用的词,通常难以明确界定其所属领域。在某些应用中并非必须确定词和领域的明确关系,仅仅依赖词的领域性的量化值就能够取得较好的效果。该文根据大规模语料库中词的关联信息,采用无指导的方法,对词的领域性进行量化,其结果可以作为词的一种特征应用于文本分类、话题检测、信息检索等相关的自然语言处理中。最后,通过和常用的特征——TFIDF在话题检测应用中进行对比,证明了其有效性。