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排序方式: 共有513条查询结果,搜索用时 31 毫秒
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Amol P. Amrute Ankur Bordoloi Nishita Lucas K. Palraj S. B. Halligudi 《Catalysis Letters》2008,126(3-4):286-292
MoO3/SiO2 composite with varying amounts of MoO3 loading (1–20 wt.%) were prepared by sol–gel method and calcined at 500 °C. These catalysts were employed for the liquid phase condensation of anisole with paraformaldehyde. All the catalysts were characterized by N2 sorption, XRD, and NH3-TPD. The activities of synthesized MoO3/SiO2 catalysts were compared with p-toluene sulfonic acid (p-TSA), the most frequently used catalyst for the condensation reactions, and with a supported metal oxide (WO x /ZrO2). Under the similar reaction conditions, synthesized 10 wt.% MoO3/SiO2 catalyst calcined at 500 °C was found to be the most active in the condensation of anisole with paraformaldehyde. 相似文献
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In both the dc polarography and in the square wave polarography, the Stokes—Einstein—Ilkovi? equation connecting polarographic current and viscosity of the solution, is valid only in the case of monomeric solutions. In solutions of polymers, the polarographic diffusion current is higher than it would be expected from the macro-viscosity. The phenomenon is explained by the fact of micro-viscosity which is lower than macro one and controls the diffusion of small species like inorganic cations. They do not “see” long chains and coils of polymers. Paper discusses the phenomenon from different points of view: electrochemical (filling the gap in general application of square wave polarography) and physicochemical (diffusion of cations as a means of investigation of the structure of polymeric solutions). Conclusions of the paper are also important for radiation chemistry where discussion of diffusion of small species cannot be done in terms of macro-viscosity. 相似文献
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Optimum selection of abrasive flow machining conditions during fine finishing of Al/15 wt% SiC-MMC using Taguchi method 总被引:2,自引:2,他引:0
Harlal Singh Mali Alakesh Manna 《The International Journal of Advanced Manufacturing Technology》2010,50(9-12):1013-1024
Abrasive flow machining (AFM) is gaining widespread application finishing process on difficult to reach surfaces in aviation, automobile, and tooling industry. Al/SiCp-MMC is a promising material in these industries. Here, AFM has been used to finish conventionally machined cylindrical surface of Al/15 wt% SiCp-MMC workpiece. This paper presents the utilization of robust design-based Taguchi method for optimization of AFM parameters. The influences of AFM process parameters on surface finish and material removal have been analyzed. Taguchi experimental design concept, L18 (61?×?37) mixed orthogonal array is used to determine the S/N ratio and optimize the AFM process parameters. Analysis of variance and F test values also indicates the significant AFM parameters affecting the finishing performance. The mathematical models for R a, R t, ΔR a, and ΔR t and material removal are established to investigate the influence of AFM parameters. Conformation test results verify the effectiveness of these models and optimal parametric combination within the considered range. Scanning electron micrographs testifies the effectiveness of AFM process in fine finishing of Al/15 wt% SiCp-MMC. 相似文献
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激光器调Q技术是产生高峰值功率、窄脉冲的最有效方法之一。提出并初步验证了全光纤对接损耗调Q方法,分析了调Q原理以及影响因素,实现调Q脉冲的输出。激光腔内加入两段光纤,两段光纤间相互靠近的一端紧密对接,其中一段粘结在压电陶瓷(PZT)上。通过外部电压变化驱动压电陶瓷,使两光纤端面间出现轴向间隙、径向错位或旋转夹角,改变两段光纤之间的耦合连接损耗,进而调节激光腔的损耗,输出调Q脉冲。采用径向错位方式,可以有效改变光纤之间的耦合连接损耗,重复频率可达10 kHz。该方法实现简单,成本低廉,通过外部条件控制,可进一步提高输出脉冲的稳定性。 相似文献
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Wireless Personal Communications - The advancements of technology in the field of communication made WSN based IoT attractive and applicable to various areas. It is comprised IoT nodes that work on... 相似文献
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Patil Rupesh C. Jagdale Ashutosh A. Patil Uttam P. Ghodake Jeevan S. Mali Sawanta S. Hong Chang K. Patil Suresh S. 《Catalysis Letters》2021,151(12):3617-3631
Catalysis Letters - We converted agro-waste Custard Apple Peels (CAP) to ash via thermal treatment, on which Pd(OAc)2 was immobilized easily that produced a low-cost, highly efficient Pd/CAP-ash... 相似文献