不同熔化速率下的电渣重熔过程数值模拟分析     

贺铸  蔡辉  刘双  王强  李宝宽 《保鲜与加工》2015,(5):104-111

电渣重熔能提高钢锭的质量,从而满足特种行业的需要,其过程伴随着复杂的物理现象,存在着磁流体流动、传热和传质以及电化学等多方面的影响。通过耦合电磁以及流动和温度方程对电渣重熔过程的三维瞬态进行了数学模拟,研究了熔化速率对重熔过程的影响。结果表明：电流密度、焦耳热和电磁力都随着熔化速率的增大而增大,当熔化速率由14.4 kg/h增加到27.0kg/h,电流密度、焦耳热和电磁力最大值的增大比例超过100%。随着熔化速率的增大,温度最大值有小幅的增加,而且速度最大值的增大幅度接近50%;金属熔池深度则由27 mm增大到38 mm,不利于保证铸坯的质量。  相似文献   

Model of Financing Strategy     

FU Qiang  PENG Long-ze  ZHANG Tian-yong 《保鲜与加工》2006,(3):143-146

Considering information asymmetry between inside and outside of the firms,this paper discusses the financing strategy of M&A,and builds a model.According to the model,we can see that the firm with relatively expected low-productivity will choose equity financing for M&A,and the firm with relatively expected high-productivity will choose debt financing for M&A,and the firm with expected medium-productivity will not choose financing from outside.In the case of undeveloped capital market and financing tools in China,the conclusion of the model has some extent significance for helping firms to choose financing strategy for M&A rationally.  相似文献   

Dropwise Condensation Heat Transfer Coefficient on the Horizontal Circular Surface with Radial Gradient Surface Energy     

GU Yang-biao  LIAO Qiang  ZHU Xun  WANG Hong 《保鲜与加工》2006,(5):48-51

A theoretical model is developed for the dropwise condensation heat transfer on the horizontal circular surface with radial gradient surface energy based on the heat transfer model of individual condensate drop and the size distribution model of condensate drop on homogeneous condensation surface.The effect of variation of contact angle on the gradient surface on condensation heat transfer and condensate drop size distribution is taken account of in this model.The theoretical calculation method was obtained to predict the dropwise condensation heat transfer coefficient on the horizontal circular surface with radial gradient surface energy under various wall subcooled temperature,contact angle profile on wall surface,and working fluid.The effects of surface energy gradient,wall subcooled temperature,and thermophysical properties of condensate on the condensation heat transfer are discussed respectively.The calculation results show that the condensation heat transfer coefficient increases slightly with the increase of wall subcooled temperature.As latent heat and surface tension increasing,the condensation heat transfer coefficient increases.A larger surface energy gradient induces a larger condensation heat transfer coefficient.  相似文献   

Design for Precision Measurement System Based on Machine Vision     

LIAO Qiang  MI Lin  ZHOU Yi  XU Zhong jun 《保鲜与加工》2002,(12):21-23

It is difficult to measure the geometric quantity of small parts in finishing, assembling and measuring, because it's easy to break the workpieces' surface and alter their position by means of traditional contact measuring methods.There are some non contact measurers, such as,light feeler pin and interference microscope etc., because of it's high price and strict working conditions,so it's difficult to promote them in widely use. Precision measurement system based on machine vision has the advantages of non contact measuring as well as high performance and low price. Some problems, such as light source, algorithm of edge fitting, auto focusing,are discussed.  相似文献   

Penetration behavior of bath induced by top-blown gas jets for steelmaking converter     

LI Mingming  LI Qiang  ZHANG Wei  ZOU Zongshu 《保鲜与加工》2015,(2):58-63

The cavity induced by top-blow gas jets impinging on the bath surface is one of most important parameters, which has overwhelming influence on the rate of slag formation and metallurgical performance. Water model experiments are conducted through a 1/10 scaled-down top-blown convertor. Effects of lance height and gas flow rate on penetration behavior are studied, and also the influence mechanism of liquid surface tension on penetration depth is addressed based on the experiments and theory analysis. An energy utilization index (EUI) is defined to reflect how much the impinging kinetic energy of gas jets are transferred into bath for formation of cavity, and an improved model is proposed to predict penetration depth of jets. The results show that penetration depth increases with lowering lance height and increasing gas flow rate, and impact diameter increases with increasing lance height, but is little affected by gas flow rate. Influence of liquid surface tension on penetration depth is enhanced with increasing surface tension and penetration depth. The EUI increases with increasing lance height, and a function relationship of it with lance height is obtained based on the experiments.  相似文献   

Existing Situation on Disposal of Sludge from Wastewater Treatment Plant in Three-Gorges Reservoir Area     

HE Qiang  ZHOU Jian  HUANG Ming 《保鲜与加工》2007,(3):1

At present 18 wastewater treatment plants operateing in the Small towns of Three Gorge Areas of Chongqing Municipality, producing 132.95 tons surplus sludge everyday. As regards to the disposition of such numerous surplus sludge, the major disposition technique in these wastewater water treatment plants, i. e. , thickening and mechanical dewatering technique followed by feeding into the municipal solid waste landfill, seems to have a rather bad effect on the normal operation of the municipal solid waste landfill, due to the unstabilized sludge resulted from this technique of the sludge disposition and high moisture in the sludge, which is higher than 80%. This paper has paid some attention to this phenomenon. With respect to the small towns having the the municipal solid waste landfill, the techniques of mechanical dewatering, calcareousness stabilized etc. before feeding into the municipal solid waste landfill, seem to be feasible, while the composting and comprehensive utilization of sludge is available in the small towns which have no municipal solid waste landfills.  相似文献   

Multiple Layer BP Neural Network for Fuzzy Calculating     

Zou Xiaoji  Zang Anbang  Zou Jiaqi 《保鲜与加工》1996,(3):57-60

The FCBP(Fuzzy calculating BP) algorithm which is proposed by this paper hasovercome the sensitivity for samples,reduced the number of input layer's samples,lightened the burden of input layer.it is suitable to fuzzy inference and pattern recognition.  相似文献   

Cryptography of Combining Hardware and Software Based On Chaotic Algorithm     

YANG Xin  LI Qiang  HUANG Xi-yue 《保鲜与加工》2005,(2):74

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Experimental Study on the Extended Length of Negative Reinforcement Cut-in Phases in Continuous Beams     

Zou Zhaowen  Fu Jianping  Bai Shaoliang 《保鲜与加工》1996,(2):10-19

In this paper through the static loading tests of 6 inflexion zones and 2 cantilever zones in full-size constrained R/C beams, the stress performance in rebars cut-in-phases and subjected to negative moment is studied. The stress properties of extended length of rebars with different shear-span ratiosare analysed on basis of the full measurement of strain distributions combined with the investigation on state and regularity of the diagonal cracks development and series of new knowledge are obtained. It is found that current Concrete Design Code provisions on the extended length are inadequate for the high shear-span ratio and superfluous for the low shear-span ratio. The theoretical and experimental foundations are provided for determining proper value of extended length for rebars cut-in-phases.  相似文献   

Study on The origin of The Cracks And Their Elinination In Expanded Pearlite And Waste Glass Compound Decorative puank     

Zhang Zhiqiang  Lu Jian  Wu Fang  Zou Yicong 《保鲜与加工》1995,(3):60-64

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