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钢液真空循环精炼过程的物理模拟 总被引：2，自引：0，他引：2
魏季和 《上海大学学报(英文版)》2003,7(1):1-17
1 Ｉｎｔｒｏｄｕｃｔｉｏｎ Ａｓａｓｅｃｏｎｄａｒｙｓｔｅｅｌｍａｋｉｎｇｔｅｃｈｎｏｌｏｇｙ ,ｔｈｅＲＨ(Ｒｕｈｒｓｔａｈｌ Ｈｅｒａｅｕｓ)ｖａｃｕｕｍｃｉｒｃｕｌａｔｉｏｎｒｅｆｉｎｉｎｇｐｒｏ ｃｅｓｓｈａｓｂｅｅｎａｐｐｌｉｅｄｗｉｄｅｌｙａｎｄｄｅｖｅｌｏｐｅｄｒａｐｉｄｌｙｉｎｐｒｅｖｉｏｕｓｆｏｕｒｄｅｃａｄｅｓ .Ｗｉｔｈａｃｏｎｔｉｎｕｏｕｓｌｙｇｒｏｗｉｎｇｄｅｍａｎｄｆｏｒｈｉｇｈｑｕａｌｉｔｙａｎｄｈｉｇｈｌｙｃｌｅａｎｓｔｅｅｌ,ｉｔｈａｓｎｏｗｂｅｃｏｍｅ ,ｔｏａｃｏｎｓ… 相似文献
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DMA传送是一种计算机内存与外设数据交换的重要方式．本文给出一DMAC接口实验，旨在学生学习DMAC接口时．能具体了解DMAC的工作原理及其编程方法。 相似文献
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The transverse injection flow field has an important impact on the flowpath design of scramjet engines. At present a combination of the transverse injection scheme and any other flame holder has been widely employed in hypersonic propulsion systems to promote the mixing process between the fuel and the supersonic freestream; combustion efficiency has been improved thereby, as well as engine thrust. Research on mixing techniques for the transverse injection flow field is summarized from four aspects, namely the jet-to-crossflow pressure ratio, the geometric configuration of the injection port, the number of injection ports, and the injection angle. In conclusion, urgent investigations of mixing techniques of the transverse injection flow field are pro- posed, especiaUy data mining in the quantitative analytical results for transverse injection flow field, based on results from multi-objective design optimization theory. 相似文献
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In this paper, the characteristics of fluid mixing time in a novel extra-loop fluidized bed were studied. The results showed that the mixing time was shortened with the increase of fluid velocity. All the discrete numbers of the reactor were above 0.2. The serial number n was 2.5 -3.0. It was judged accordingly that the reactor fluid state was continous stirred tank reactor （CSTR） mainly. When the inspiratory capacity increased the mixing time of the reactor was shortened. Thus the air input was beneficial for the fluid mixing. During the three phases mixing process, the mixing time of the reactor could be decreased by the n increase of carrier and air loading together, but the change was not significant. The parameters affecting the reactor fluid state were fluid velocity, inspiratory capacity and carrier. KLa could be increased with the air loading increase, and at the same gas/liquid ratio when the pressure drop was high, KL~ value was increased. The amount of carrier complex influence on KLa. As the carrier loading continued to increase, its value had been dropped but the changes was not significant, and optimization condition was found at above 800 1 000 g carrier loading （pouzzolane） or 600 g PVC. Under gas/liquid ratio of 0.8% -5.2%, KLa was （0.62-1.37）×10^-2· s^-1. 相似文献
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建立了同向自洁双螺杆端面内二维周期性流动的物理模型及数学模型。借助商用有限元软件POLYFLOW叠加网格技术求解得到速度场,基于具有4阶精度的RungeKutta数值积分方法自行开发了流体前锋追踪代码,并对对混合过程动力学进行了数值模拟表征。采用粒子群可视化模拟、Poincaré截面分析、界面演化及界面增长等探讨了混合过程动力学细节,揭示混沌混合作用的尺度。结果表明,传统的同向双螺杆端面内混沌混合与常规的层流混合共存,不同区域的混合效果相差很大。螺槽中部存在8字型准周期运动带,带内混合为常规的层流混合。 相似文献
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Axialmixing ,or“longitudinaldispersion”and“backmixing”interminology,isanimportantnon idealflowphenomenoncommonlyoccurringinchemicalengi neeringprocess,suchasdistillation ,absorption,extrac tion,etc.Thisphenomenonrepresentsadeviationfrompistonflowandusuallyformsaparabolicaxialconcentra tionprofilealongtheflowdirection.Theunfavorableef fectofaxialmixingisthatitdecreasesthemasstransferdrivingforcesandfinallyleadstopoorerseparationeffi ciency.Instructuredpackedtower,althoughtheaxialmixingcanbe… 相似文献
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Danckwert's method was used to determine the specific interfacial area, a, and the individual mass transfer coefficient, kL, during absorption of CO2 in a bubble column with an anionic surfactant in the carbonate-bicarbonate buffer solution and NaAsO2 as catalyst, the presence of which decreases the specific interfacial area and the individual mass transfer coefficient. The specific interfacial area and the individual mass transfer coefficient increase with increasing superficial gas velocity. The specific interfacial area decreases whereas the individual mass transfer coefficient increases with increasing temperature. The results of experiments were used to determine the dependence of a, kL, and kLa on the surface tension, the temperature of the absorption phase, and the superficial velocity of the gas. The calculated results from the correlation were found to be within 10% deviation from the actual experimental results. 相似文献
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In this paper, based on the principle of heat transfer and thermal elastic-plastic theory, the heat treatment process optimization scheme for face gears is proposed according to the structural characteristics of the face gear and material properties of 12Cr2Ni4 steel. To simulate the effect of carburizing and quenching process on tooth deformation and residual stress distribution, a heat treatment analysis model of face gears is established, and the microstructure, stress and deformation of face gear teeth changing with time are analyzed. The simulation results show that face gear tooth hardness increases, tooth surface residual compressive stress increases and tooth deformation decreases after heat treatment process optimization. It is beneficial to improving the fatigue strength and performance of face gears. 相似文献
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叶昌元 《岳阳职业技术学院学报》2007,22(1):24-28
核心能力的培养需要让学生在活动中进行,在全方位参与活动的过程中将与该活动相关的理论知识、实践知识和人文知识都结合起来,让学生进行综合性学习,让学生把所学的知识转化为能力和素质。让学生进行综合性学习,就需要教师改变传统的学科教学的理念,按跨学科的以活动为中心的要求编写让学生进行综合性活动学习的教材——学习领域教材。 相似文献
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The efficacy of traditional Chinese medicine (TCM) is based on the combined effects of its constituents. Variation in chemical composition between batches of TCM has always been the deterring factor in achieving consistency in efficacy. The batch mixing process can significantly reduce the batch-to-batch quality variation in TCM extracts by mixing them in a well-designed proportion. However, reducing the quality variation without sacrificing too much of the production efficiency is one of the challenges. Accordingly, an innovative and practical batch mixing method aimed at providing acceptable efficiency for industrial production of TCM products is proposed in this work, which uses a minimum number of batches of extracts to meet the content limits. The important factors affecting the utilization ratio of the extracts (URE) were studied by simulations. The results have shown that URE was affected by the correlation between the contents of constituents, and URE decreased with the increase in the number of targets and the relative standard deviations of the contents. URE could be increased by increasing the number of storage tanks. The results have provided a reference for designing the batch mixing process. The proposed method has possible application value in reducing the quality variation in TCM and providing acceptable production efficiency simultaneously. 相似文献
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蔡剑英 《福建工程学院学报》2012,(4):383-387
随着我国城市化进程的加快和乡镇经济的蓬勃发展,集体建设用地的流转规模不断扩大,但其流转价格也普遍出现了扭曲现象,不利于资源配置的最优化。文章主要运用经济学相关理论对集体建设用地流转价格扭曲的原因进行了综合分析,并结合我国土地市场的现实状况讨论了相应的流转价格鉴定方法——收益还原法、成本法、市场比较法,详述了这些方法的计算公式,运行步骤及其需注意的相关问题。 相似文献
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课堂教学活动是由教师、学生所组成的一个信息传递与交流系统,是一种特殊的传播活动。从传播学的角度看,课堂教学也是由信源、编码、信道、译码、信宿、干扰及反馈组成的信息传递系统。分析该系统中影响教学传播效果的教师、学生、教学内容、教学媒体等因素,依据传播效果优化原理:共同经验原理、抽象层次原理、信息来源原理、重复作用原理等进行优化,是提高课堂教学质量的重要途径。 相似文献
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LIU Sean X. 《浙江大学学报(A卷英文版)》2006,7(11):1911-1916
INTRODUCTION Chlorinated hydrocarbons, a class of widely used dry-cleaning liquids, industrial organic solvents, and degreasers, increasingly find their way into drinking water sources, thus posing a very serious health and environmental problem (Love and Eliers, 1982). These organic solvents are known for their stability in the environment and cancer-causing po- tency and cannot be effectively and economically eliminated by current conventional treatment tech- nologies. One of the few av… 相似文献
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INTRODUCTION With worldwide increase of air pollution and the environmental consciousness of governments, people have to look for new resources to mitigate the energy crisis and improve the present environmental status (Ferng et al., 2004; Rowe and Li, 2001). Fuel cells are highly efficient and environmentally clean electrical generators (Mann et al., 2000) that convert the chemical energy of a gaseous fuel directly into elec-tricity energy and play an important role in solving the prob… 相似文献
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文章采用有限元方法数值研究了封闭方腔自然对流传热问题,并基于场协同理论分析了速度场与温度梯度场的协同关系,进一步深层次分析了协同角场同速度场、温度场、温度梯度场之间的协同关系,展示了不同瑞利数下方腔自然对流速度场和温度梯度的协同效果,着重探讨了各物理场对封闭方腔协同角的影响规律,同时表明以协同角为评价指标,可有助于改善局部的传热效果,从而深层次理解强化自然对流传热的机理,为实际工程的传热强化提供了理论依据。 相似文献
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建立了模拟逆流降膜除湿过程传热传质的数学模型,给出了传热传质的控制方程和适当的边界条件和气液界面条件.采用氯化钙作为除湿剂,运用控制容积法对降膜除湿溶液与被处理空气之间的除湿过程进行了分析和计算.获得了相应的除湿溶液与被处理空气的速度场、温度分布和出口参数.计算结果表明:沿着除湿器高度方向溶液和空气的温度、溶液的浓度、空气的湿度在入口区域变化较快而在出口区域变化较慢.可分别通过增加竖壁的高度、溶液的入口浓度和溶液的流速来改善除湿过程;同样,也可通过降低空气的流速或空气入口湿度达到改善除湿过程的目的.研究结果有利于改进除湿器的性能,为太阳能液体除湿、空调系统的优化设计和运行调节提供了理论依据. 相似文献
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This study explored the role of learner-generated and instructor-provided visuals in learning from scientific text. 134 college students studied a lesson on the human circulatory system and then completed recall and transfer tests. Across two consecutive study periods, students were randomly assigned to either view a provided illustration twice (provided-provided), generate a drawing from the text and then revise their drawing (generated-revised), view a provided illustration and then generate a drawing (provided-generated), or generate a drawing and then view a provided illustration (generated-provided). Results indicated a group by learning outcome interaction: the generated-provided and provided-generated groups performed higher on the transfer test and lower on the recall test compared to the provided-provided group. Furthermore, spatial ability was positively associated with learning outcomes among students who generated drawings but not among students in the provided-provided group. Finally, the relationship between spatial ability and learning outcomes among students who generated drawings was mediated by drawing quality. These findings suggest that provided and generated visuals have unique effects on different learning outcomes, and spatial ability plays an important role in supporting learner-generated visuals. 相似文献
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利用专业的多物理场耦合软件COSMOLMultiphysics对sK型静态混合器内的不可压缩层流流场进行了仿真模拟,计算过程中采用软件中的层流流动和稀物质的传递内置模块,得到了静态混合物中流体的浓度场、速度场及压力场分布。由于螺旋混合元件的作用,流体做螺旋运动,通过对流体的剪切、旋转,使流体充分混合,结果在出口处几乎混合完全。利用后处理软件对计算结果进行分析,为其性能测试提供了理论依据。 相似文献
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为克服粒子群算法在处理复杂高维问题时易陷入局部最优及寻优精度低等缺陷,提出一种融合 Rosenbrock 搜索法的混合粒子群算法。首先,利用 Tent 混沌序列进行种群初始化;其次,采用去速度项的简化粒子群公式提高收敛速度并对个体极值加入扰动,增强粒子种群多样性;最后,当全局最优个体更新停滞时,利用Rosenbrock 搜索法对全局最优个体进行局部搜索,提高解的精度。利用 8 个常用基准测试函数分别对 30 维和50 维问题进行实验,证实该算法可寻到病态函数 Rosenbrock 全局最优值,且比其它 7 个函数的寻优精度提高10-2 数量级。实验证明该算法收敛速度快,解的精度高,全局搜索能力强,寻优能力明显提高。 相似文献