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测量透明平板表面形貌的相位共轭干涉仪
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《科技开发动态》 2003年第3期47-47,共1页
关键词 测量 透明平板表面形貌 相位共轭干涉仪
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平面布置振荡热管壁面温度分布特性实验研究 被引量:2
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作者 赵孝保 李奇贺 +1 位作者 董宏伟 恽超 《南京师范大学学报(工程技术版)》 CAS 2005年第1期16-19,共4页
实验测量了由振荡热管冷凝段构成的平板表面中管束壁面上横向和纵向温度,对升负荷和降负荷过程中壁面温 度分布特性进行了分析.实验表明平板表面外侧管壁面温度波动幅度较大,中间点温度比较均匀;受管束内汽液流动及剧烈 振荡的影... 实验测量了由振荡热管冷凝段构成的平板表面中管束壁面上横向和纵向温度,对升负荷和降负荷过程中壁面温 度分布特性进行了分析.实验表明平板表面外侧管壁面温度波动幅度较大,中间点温度比较均匀;受管束内汽液流动及剧烈 振荡的影响,在热管蒸发段壁面温度达到90℃时,平板表面温度均匀程度最好;当蒸发段壁面温度为120℃时,横向各点温 度相差比较大.管束壁面纵向温度分布实验表明:蒸发段壁面温度为40℃时,热管未启动;而在120℃时热管完全启动,各测 点温度相差不大;在60℃~80℃时,纵向温度相差较大,温度分布不均匀,靠近蒸发段的测点温度升高较快;蒸发段壁面温度 在80℃以上时,平板表面纵向温度趋于均匀. 展开更多
关键词 振荡热管 温度分布 平板表面 温度均匀度
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纯水和氯化钠溶液凝固过程的实验研究 被引量:3
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作者 刘圣春 姜婷婷 董紫腾 《化工进展》 EI CAS CSCD 北大核心 2016年第B11期68-74,共7页
近几年国内外学者对冰浆的各种特性进行了大量研究,但大多都集中在冰浆生成器的装置设计、冰浆在管道中的流动及传热特性,很少有从冰晶颗粒在壁面生成及结晶过程的机理进行研究讨论。本文对纯水和不同浓度氯化钠溶液在不同材料表面的凝... 近几年国内外学者对冰浆的各种特性进行了大量研究,但大多都集中在冰浆生成器的装置设计、冰浆在管道中的流动及传热特性,很少有从冰晶颗粒在壁面生成及结晶过程的机理进行研究讨论。本文对纯水和不同浓度氯化钠溶液在不同材料表面的凝固特性进行了实验研究,搭建了多组分溶液表面凝固性能研究装置,并对装置布置测点同时可更换测试表面。实验采取不同浓度的氯化钠溶液,分别记录在粗糙度不同的铜板、铝板以及塑料板表面凝固时的温度、时间,分析不同表面粗糙度、不同材质以及氯化钠浓度对溶液成核能的影响。通过对实验数据的分析和处理分别得出开始凝固温度与粗糙度的变化关系以及凝固时间与过冷度的变化关系。实验结果表明:溶液在平板表面凝固的初始温度会随着粗糙度的增大而逐渐升高。溶液在平板表面凝固的凝固时间会随着过冷度的增大而逐渐降低。 展开更多
关键词 氯化钠溶液 平板表面 结晶 粗糙度 过冷度
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冷冻畜禽肉品菌落总数测定方法的探讨 被引量:4
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作者 潘新南 《中国卫生监督杂志》 2003年第1期54-56,共3页
探讨冷冻畜禽肉菌落总数测定方法的改进。采用倾注平板法和平板表面涂布法接种 ,并分别于2 5℃和 36℃培养进行对比试验。采用平板表面涂布法接种 ,2 5℃培养的检测结果比国标法能更有效地检出样品中的活菌数。说明改进冷冻畜禽肉菌落... 探讨冷冻畜禽肉菌落总数测定方法的改进。采用倾注平板法和平板表面涂布法接种 ,并分别于2 5℃和 36℃培养进行对比试验。采用平板表面涂布法接种 ,2 5℃培养的检测结果比国标法能更有效地检出样品中的活菌数。说明改进冷冻畜禽肉菌落总数测定方法是非常必要的。 展开更多
关键词 冷冻畜禽肉品 菌落总数 测定方法 倾注平板 平板表面涂布法
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Effects of continuous casting mould fluxes on reducing longitudinal and star cracks on a slab surface 被引量:1
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作者 WANGQian WANGYu +4 位作者 CHIJinghao XIEBing HEYuming ZHUBing CHENWenman 《Journal of Chongqing University》 CAS 2004年第1期65-68,共4页
In the continuous casting production of medium carbon steel (whose mass fraction of carbon is 0.09 % to 0.16 %) and high strength low alloy steel (whose mass fraction of Mn is 0.90 % to 1.40 %), flecks occurring the m... In the continuous casting production of medium carbon steel (whose mass fraction of carbon is 0.09 % to 0.16 %) and high strength low alloy steel (whose mass fraction of Mn is 0.90 % to 1.40 %), flecks occurring the most often are usually longitudinal and star cracks. In additional to the employment of a galvanized plate mould, two kinds of fluxes with special properties were studied and used to harmonize the conflicts between the function of heat transfer and lubrication. An industrial application revealed that the crystallizing temperature (Tc) and crystal ratio (R) of fluxes have a crucible effect on impeding the occurrence of above defects on a slab surface. In the case of slab section (180 to 240) mm(1000 to 1400) mm and casting speed Vc of (0.7 to 1.2) m/min, the optimized parameters of fluxes are Tc of (1170 to 1190) ℃, R of 80 % to 95 % for medium carbon steel, and Tc of (1100 to 1150) ℃, plus R of 40 % to 60 % for high strength low alloy steel. 展开更多
关键词 continuous casting mould flux star crack longitudinal crack
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A Study on Modelling Surface Finish in Electrical Discharge Machining Tablet Shape Punches Using Response Surface Methodology
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作者 Le Xuan Hung Tran Thanh Hoang Vu Ngoc Pi 《Journal of Environmental Science and Engineering(B)》 2017年第7期387-390,共4页
This paper introduces a study on modelling surface finish in EDM (Electrical Discharge Machining) of tablet shape punches when using copper as electrode material. In this study, 27 experiments were performed based o... This paper introduces a study on modelling surface finish in EDM (Electrical Discharge Machining) of tablet shape punches when using copper as electrode material. In this study, 27 experiments were performed based on BBD (Box-Behnken Design) and the work-piece material was 9CrSi steel. The input process parameters were the current, the pulse on time, the pulse off time and the voltage. The effects of the input parameters on the surface finish were evaluated by analysing variance. Besides, from the results of the experiments, a regression equation for determining the surface roughness is introduced. Also, the optimum input parameter values were found in order to get the minimum surface roughness. 展开更多
关键词 EDM (Electrical Discharge Machining) EDM sinking surface roughness RSM (Response Surface Methodology) BBD(Box-Behken Design).
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Implementation of a Roughness Element to Trip Transition in Large-eddy Simulation 被引量:2
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作者 J.Boudet J.-F.Monier F.Gao 《Journal of Thermal Science》 SCIE EI CAS CSCD 2015年第1期30-36,共7页
In aerodynamics, the laminar or turbulent regime of a boundary layer has a strong influence on friction or heat transfer. In practical applications, it is sometimes necessary to trip the transition to turbulent, and a... In aerodynamics, the laminar or turbulent regime of a boundary layer has a strong influence on friction or heat transfer. In practical applications, it is sometimes necessary to trip the transition to turbulent, and a common way is by use of a roughness element (e.g. a step) on the wall. The present paper is concerned with the numerical im- plementation of such a trip in large-eddy simulations. The study is carried out on a flat-plate boundary layer con- figuration, with Reynolds number Rex=l.3x 106. First, this work brings the opportunity to introduce a practical methodology to assess convergence in large-eddy simulations. Second, concerning the trip implementation, a volume source term is proposed and is shown to yield a smoother and faster transition than a grid step. Moreover, it is easier to implement and more adaptable. Finally, two subgrid-scale models are tested: the WALE model of Nic0ud and Ducros (Flow Turbul. Combust., vol. 62, 1999) and the shear-improved Smagorinsky model of Ldv^que et al. (J. Fluid Mech., vol. 570, 2007). Both models allow transition, but the former appears to yield a faster transition and a better prediction of friction in the turbulent regime. 展开更多
关键词 large-eddy simulation boundary layer roughness element TRANSITION TRIPPING
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