共查询到20条相似文献,搜索用时 171 毫秒
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椭圆形封头的快速定量画法赵济汉(东台市锅炉压力容器检验所)陈晓岷(东台市钼酸化工厂)关键词椭圆形封头画法在椭圆形封头的制图中,一般通过取点用曲线板或直接用四心圆作图法作出封头的近似图,但曲线板作图误差较大,四心圆法作图又较繁琐。故笔者对四心圆作图法... 相似文献
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采用固体分散技术,制备清肺止咳平喘微丸。实验成选工艺为:于麻黄、苦杏仁、石膏、炙甘草混合提取物中加入少量无水乙醇,60℃熔融后,加入熔融的聚乙二醇,保温于90±6℃,用内口径4.80mm,外口径6.44mm的滴头,以23粒/min的速度滴入甲基硅油冷却剂中,收集微丸。初步药效学表明,微丸在止咳、平喘、抗炎方面与合剂有相当的作用。 相似文献
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PET装置中椭圆形封头卧式容器的液位-体积计算 总被引:1,自引:0,他引:1
针对椭圆形封头卧式容器的特点进行数学分析,得出椭圆形封头卧式容器内不同液位及对应液体体积的函数关系式。再以PET装置中具有标准椭圆形封头(EHA)的卧式EG液封槽17-T02为例,验证了计算结果和实际生产中标定数值具有很好的一致性,表明该函数关系式可以用来指导设计及实际生产操作。 相似文献
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推导了折边锥形封头高度,体积和质量的计算公式,计算结果与行业标准完全吻合,计算公式还能适用于非标的锥形封头。 相似文献
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Stefan Blaser 《Chemical engineering science》2002,57(3):515-526
Knowledge of the forces which a fluid motion exerts on the surface of suspended material is important for many processes in which the particles are broken apart by the hydrodynamic forces. In this paper, we examine the stresses on a small ellipsoidal particle which is immersed in either a constant, simple shear, two-dimensional straining or axisymmetric straining flow. Calculations have been performed using Oberbeck's and Jeffery's models and have been appropriately visualized. Furthermore, the motion and orientation of the ellipsoid have been examined and the extreme values of stresses have been analyzed. A simple criterion for the break-up of particles is proposed. The analysis shows that the straining flows are particular important for the load on particles. In contrast, simple shear flows are less crucial as the presence of vorticity leads to a rotation of the particles. 相似文献
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The wetting and spreading characteristics of a water drop on a surface is highly dependent on the geometric parameters of the micro-texture of the surface. To obtain a stable Cassie drop, the condition that the pillar height must be higher than the sag height of the meniscus is a necessary, yet not a sufficient, condition. From the viewpoint of energy minimization, a new criterion was proposed to design the height of the pillar for achieving a stable and robust anti-adhesive drop state. To ensure such a composite interface, the height of the pillars should be taller than the critical height where the critical contact angle is equal to the intrinsic contact angle. If this height requirement is not met, the drop exists in either a Wenzel or a metastable Cassie state. The numerical simulations using the Volume-of-Fluid method in Fluent support the above proposals. 相似文献
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Carlos Echaide-Górriz Magdalena Malankowska Carlos Téllez Joaquín Coronas 《American Institute of Chemical Engineers》2020,66(6):e16970
The inner and outer surfaces of a porous hollow fiber polysulfone support are compared as substrates for the synthesis of polyamide thin-film composite (TFC) membranes by interfacial polymerization. While both surfaces have pores common of microfiltration membranes, the inner surface has a larger pore diameter than the outer surface (2,700 nm compared to 950 nm). The inner TFC membrane showed higher water nanofiltration permeance than the outer (2.20 ± 0.17 compared to 0.13 ± 0.03 L m−2 hr−1 bar−1). This was due to the influence of the porosity and roughness, which were different on both support surfaces. These membranes are interesting because they were synthesized in a hollow fiber support with a high membrane area per volume unit (~6,900 m2/m3) and the substrate used was commercial, which means that the TFC membrane obtained is suitable for industrial application. A mathematical simulation of the nanofiltration run with COMSOL Multiphysics 5.3 software confirmed the experimental trends observed. 相似文献
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An infrared spectrophotometric procedure, based on the fatty acid methyl ester mixture derived from a partially hydrogenated
vegetable oil as the calibration standard, has been developed for accurate analysis of the totaltrans content of hydrogenated fats. This procedure produces more accurate results than the current official methods of Association
of Official Analytical Chemists and American Oil Chemists’ Society, both of which use methyl elaidate as the external standard.
The results obtained with this procedure were in close agreement to those determined by the combined procedure of silver-nitrate
thin-layer chromatography and capillary gas-liquid chromatography. The improved results, obtained with the partially hydrogenated
vegetable oil methyl esters as the calibration standard, may be attributable to its assortment oftrans isomers, which may have different absorptivities relative to methyl elaidate. 相似文献
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《Journal of Adhesion Science and Technology》2013,27(10):899-909
An analytical approach for the adhesion of a semi-infinite elastic body in contact with a sinusoidal rigid surface under zero external pressure is presented. Although Johnson (Int. J. Solids Struct. 32, 423 (1995)) has proposed an analytical solution for a slightly wavy surface, while Zilberman and Persson (Solid State Commun. 123, 173 (2002); J. Chem. Phys. 118, 6473 (2003)) have given a numerical solution for a highly wavy surface by considering the curvature of the contact area in the calculation of the interfacial term of the total energy, our solution is not only for small amplitude of roughness (i.e., the slightly wavy surface as Johnson's) but also for large amplitude of roughness (i.e., the highly wavy surface as of Zilberman and Persson). Our solution considers the curvature of the contact area as do Zilberman and Persson. Our results which are obtained for the total energy and equilibrium condition of the system agree with both Johnson's and Zilberman and Persson's results. The effects of the material constants and the surface roughness on the adhesion are clearly expressed and discussed. 相似文献
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Anders Holmen Odd A. Lindvaag David L. Trimm 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1985,35(7):358-364
Coke formation by steam cracking of propane over preoxidised and prereduced alloy foils has been studied in a tubular reactor at 810–850°C. Coke formation on preoxidised steel involves coke formation on the oxide scale which is low and coke formation on metal exposed by spalling of the scale which is high. Surface analysis by Auger spectroscopy (AES) reveals that the surface concentration of iron and nickel is low on the oxide scale and high on the exposed metal. Coke formation on the surface of the prereduced steel is low and the surface contains chromium and manganese as the predominant metal components. Differences in the product spectra obtained over preoxidised and prereduced steels is suggested to be due to the presence of surface iron and nickel which increases the production of coke and hydrogen and decreases the production of olefins in steam cracking. 相似文献
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P. Madhusudhan Rao M.V. Landau A. Wolfson A.M. Shapira-Tchelet M. Herskowitz 《Microporous and mesoporous materials》2005,80(1-3):43-55
The Cs-salt of heteropolyacid with stoichiometry Cs2.5H0.5PW12O40 (CsHPW) was deposited selectively at the external surface of the SBA-15 silica microcrystals, inside its mesoporous channels and simultaneously at both location modes. The structure, texture and performance of these CsHPW/SBA-15 composites were compared with that of a reference bulk salt of the same composition. Location of CsHPW salt on the external surface of SBA-15 microcrystals leads to disintegration of its agglomerates increasing acidity of the catalytic phase. A novel preparation strategy consisting of grafting the basic Cs-species at the internal pores surface of SBA-15 stabilized the CsHPW phase inside the channels in form of 5–8 nm nanocrystals at 30–70 wt.% loadings. The catalytic tests demonstrated that insertion of the CsHPW catalytic phase inside the nanotubular channels of SBA-15 in combination with location of an additional amount of this phase at the external surface of SBA-15 microcrystals allows to increase the specific activity of this phase in MTBE synthesis, propionylation of anisole and alkylation of catechol with t-butanol by a factor of 1.5–3. This level of specific activity in combination with high total loading of catalytic phase >60 wt.% permit to get composite catalytic materials with catalytic activity higher by a factor of 1.2–1.5 with respect to the bulk CsHPW catalyst and stabilizing the catalytic phase against colloidization in polar media. 相似文献