共查询到20条相似文献,搜索用时 93 毫秒
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在Ti-6Al-4V钛合金表面制备了Ni-TiB_2复合镀层。通过单因素试验,研究了镀液中TiB_2的质量浓度、搅拌速率和电流密度对复合镀层中TiB_2的质量分数的影响。优选出的最佳工艺参数为:镀液中TiB_2的质量浓度12g/L,搅拌速率500r/min,电流密度3A/dm~2。同时,获得了TiB_2的质量分数较高(约为9%)的复合镀层。Ni-9%TiB_2复合镀层表面较致密,其硬度约为钛合金基体的2倍。 相似文献
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以镀层中SiC复合量为参考标准,通过正交试验,考察了SiC纳米微粒、电流密度、pH和空气流量四个因素对SiC复合量的影响,发现镀液中的SiC纳米微粒质量浓度对复合量影响最大。根据正交试验结果得出镍基SiC纳米微粒复合电镀的最佳工艺条件。在最佳工艺条件下,对Ni-SiC复合镀层表面形貌和能谱进行分析。 相似文献
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《电镀与涂饰》2016,(12)
以Q235钢板为基体,在由70.0 g/L氧化锌、180.0 g/L氢氧化钠、2.8 g/L香草醛、1 m L/L甲醛、1.0 g/L硫脲和1.0 g/L三乙烯四胺组成的普通碱性镀锌液中加入SiC微粒电镀得到Zn–SiC复合镀层。研究了电流密度、温度、SiC用量和搅拌速率对Zn–SiC复合镀层耐蚀性的影响,得到较佳工艺条件为:SiC用量8 g/L,电流密度2.5~4.0 A/dm~2,温度20~25°C,搅拌速率120 r/min。SiC的存在有利于生成晶粒细小、致密且显微硬度较高的镀层。在较佳工艺下,Zn–SiC复合镀层中SiC的质量分数为1.51%,其耐蚀性优于纯锌镀层。 相似文献
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乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。 相似文献
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D. G. Gordeev L. F. Gudarenko M. V. Zhernokletov V. G. Kudel’kin M. A. Mochalov 《Combustion, Explosion, and Shock Waves》2008,44(2):177-189
A semi-empirical equation of state for metals is described. Its capabilities are demonstrated by the example of the equation
of state for aluminum. New experimental data are presented on the location of the isentrope of aluminum for unloading from
the state at p = 229.71 GPa on the shock adiabat to an aerogel (SiO2) of density 0.08 g/cm3.
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Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 2, pp. 61–75, March–April, 2008. 相似文献
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Jorge Marcelo Romero Soledad Bustillo Hugo Enrique Ramirez Maisuls Nelly Lidia Jorge Manuel Eduardo Gómez Vara Eduardo Alberto Castro Alicia H. Jubert 《International journal of molecular sciences》2007,8(7):688-694
A thermochemical rather simple experimental technique is applied to determine the enthalpy of formation of Diperoxide of ciclohexanone. The study is complemented with suitable theoretical calculations at the semiempirical and ab initio levels. A particular satisfactory agreement between both ways is found for the ab initio calculation at the 6–311G basis This set level. Some possible extensions of the present procedure are pointed out. 相似文献
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The objective of the study was to explore the effect of the degree of deacetylation (DD) of the chitosan used on the degradation rate and rate constant during ultrasonic degradation. Chitin was extracted from red shrimp process waste. Four different DD chitosans were prepared from chitin by alkali deacetylation. Those chitosans were degraded by ultrasonic radiation to different molecular weights. Changes of the molecular weight were determined by light scattering, and data of molecular weight changes were used to calculate the degradation rate and rate constant. The results were as follows: The molecular weight of chitosans decreased with an increasing ultrasonication time. The curves of the molecular weight versus the ultrasonication time were broken at 1‐h treatment. The degradation rate and rate constant of sonolysis decreased with an increasing ultrasonication time. This may be because the chances of being attacked by the cavitation energy increased with an increasing molecular weight species and may be because smaller molecular weight species have shorter relaxation times and, thus, can alleviate the sonication stress easier. However, the degradation rate and rate constant of sonolysis increased with an increasing DD of the chitosan used. This may be because the flexibilitier molecules of higher DD chitosans are more susceptible to the shear force of elongation flow generated by the cavitation field or due to the bond energy difference of acetamido and β‐1,4‐glucoside linkage or hydrogen bonds. Breakage of the β‐1,4‐glucoside linkage will result in lower molecular weight and an increasing reaction rate and rate constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3526–3531, 2003 相似文献