SY300电解槽技术的开发与生产实践

本文通过对256台SY300(300kA)电解槽的设计和在河南豫港龙采铝业有限公司200kt/a电解系列的生产实践进行剖析，应用多模式智能控制技术和“四低一高”操作工艺。电解槽运行平糖、高效。三场设计合理．实际测试和设计值吻合。实践证明。SY300电解槽从设计到生产都已达到国际先进水平。     

GRINDING RESIDUAL STRESS OF CEMENTED CARBIDE

Grinding residual stress in the surface layer of WC-6 Wt—％Co hard alloy was measured by means of X-ray diffraction. The effects of various grinding parameters and treatment processes on the stress were studied. By means of electrolytic etching, the stress distribution along the depths beneath the surface was measured. The relationship between the stress and the service life of the alloy is discussed.     

Ni对C－B_4C－SiC复合材料显微结构与性能的影响

本文研究了烧结助剂Ｎｉ对Ｃ－Ｂ_４Ｃ－ＳｉＣ复合材料显微结构与性能的影响．Ｘ射线衍射表明Ｎｉ在烧结温度下与ＳｉＣ，Ｂ_４Ｃ人发生反应在晶界生成Ｎｉ_（４．６）Ｓｉ_２Ｂ，并产生液相，有效地促进了Ｃ－Ｂ_４Ｃ－ＳｉＣ复合材料的烧结，抑制了晶粒的长大，使复合材料密度与强度大幅度地增加，电阻率下降；同时Ｎｉ_（４．６）Ｓｉ_２Ｂ在氧化时生成致密的２ＮｉＯ·Ｂ_２Ｏ_３，包裹了易氧化的Ｂ_４Ｃ和Ｃ，有效地防止了复合材料的氧化，从而大大提高了制品的抗氧化性能．     

RELATIONSHIP OF THE PROPERTIES OF HOT－PRESSING C－BC_4－SiC COMPOSITE WITH THE CONTENT OF ADDITIVE Al

ＲＥＬＡＴＩＯＮＳＨＩＰＯＦＴＨＥＰＲＯＰＥＲＴＩＥＳＯＦＨＯＴ－ＰＲＥＳＳＩＮＧＣ－ＢＣ_４－ＳｉＣＣＯＭＰＯＳＩＴＥＷＩＴＨＴＨＥＣＯＮＴＥＮＴＯＦＡＤＤＩＴＩＶＥＡｌ￥Ｈｕａｎｇ，Ｑｉｚｈｏｎｇ；Ｔａｎ，Ｐｉｎｇ；Ｙａｎｇ，Ｑｉａｏｑｉｎ＋；Ｈ?..     

粉末注射成形低温热脱蜡的非等温动力学

利用热重法研究了石蜡在粉末注射成形中低温热脱除的非等温动力学。采用微分法和积分法来确定动力学参数。并推出石蜡在聚丙烯配方体系生坯中热脱除的动力学方程式为：－ｌｎ（１－ａ）＝Ａｅｘｐ（－Ｅ／ＲＴ）ｔｍ，（０＜ｍ＜１）。当ｍ＝０．２５时，为最可能的机理形式。热脱蜡的动力学控制步骤为石蜡在聚丙烯中的扩散过程。     

Preparation and characterization of GaN films grown on Ga-diffused Si （111） substrates

Hexagonal GaN films were prepared by nitriding Ga2O3 films with flowing ammonia. Ga2O3 films were deposited on Ga-diffused Si (111) substrates by radio frequency (r.f.) magnetron sputtering. This paper have investigated the change of structural properties of GaN films nitrided in NH3 atmosphere at the temperatures of 850, 900, and 950℃ for 15 min and nitrided at the temperature of 900℃ for 10, 15, and 20 rain, respectively. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were used to analyze the structure, surface morphology and composition of synthesized samples. The results reveal that the as-grown films are polycrystalline GaN with hexagonal wurtzite structure and GaN films with the highest crystal quality can be obtained when nitrided at 900℃ for 15 min.     

HfC改性炭/炭复合材料的烧蚀性能

采用金属盐溶液浸渍-TCVI(Thermal Gradient Chemical Vapor Infiltration)法制备了HfC改性炭/炭复合材料.通过氧-乙炔烧蚀实验测试了不同含量HfC改性炭/炭复合材料的抗烧蚀性能;利用DSC-TG,SEM,XRD分析了HfC的形成过程、材料烧蚀前后的微观形貌及物相组成.结果表明:HfC的加入降低了炭/炭复合材料的线烧蚀率,其中HfC含量为6.5%(质量分数,下同)的炭/炭复合材料的线烧蚀率最低.HfC具有抑制氧化及弥补缺陷的作用,从而降低了炭/炭复合材料的热化学烧蚀和机械剥蚀.     

EFFECTS OF PRESSURE AND TEMPERATURE ON THE MICROSTRUCTURES OF NANOCRYSTALS α-Fe_2O_3

采用沉淀法制备了α－Ｆｅ２Ｏ３超微粒，在不同的温度和压力下对超微粒粉末进行处理，利用Ｘ射线衍射和Ｍｏｓｓｂａｕｅｒ谱对高压处理前后的样品进行了分析。结果表明，压力主要对微晶的表面或纳米晶体的界面结构产生影响，使晶格畸变或无序程度增加。     

丹尼尔超声波流量计的日常维护和故障处理办法

由于超声波流量计具有抗干扰能力强、测量精度高、无压损、量程比宽和维护量小等特点,所以,被广泛应用于贸易计量中。目前,国内贸易计量所用的超声波流量计基本都依赖进口,由于其备件采购周期较长,再加上厂家的技术垄断,导致超声波流量计在出现问题时不能及时得以解决。简单介绍了丹尼尔超声波流量计的相关概念、现场诊断、故障处理办法和日常维护的注意要点。     

Petri net based test case generation for evolved specification

Model-based testing can use a model to test a concrete program’s implementation. When the model is changed due to the evolution of the specification, it is important to maintain the test suites up to date, such that it can be used for regression testing. A complete regeneration of the whole test suite from the new model, although inefficient, is still frequently used in practice. To address this problem effectively, we propose a test case reusability analysis technique to identify reusable test cases of the original test suite based on graph analysis, such that we can generate new test cases to cover only the change-related parts of the new model. The Market Information System (MIS) is employed to demonstrate the feasibility and effectiveness of the proposed method. Our experimental results show that the use of our method saves about 31.5% test case generation cost.