不同熔化速率下的电渣重熔过程数值模拟分析

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。     

Performance Analysis of MIPv4 Regional Registration Combined with Low Latency Handoffs

The mechanism of MIPv4 regional registration and the low latency handoff protocols are introduced. Ways and procedure of pre-registration handoff and post-registration handoff are discussed also. The authors analyze the performance of the low latency handoff protocols combined with low latency handoffs over a wireless access based on IEEE 802. 11 standard in a tree-like network topology. The performance of pre-registration and post-registration scheme is given by simulation.     

Analysis on Sustained Release of Protein from Microcapsule Prepared by Alginate

The paper studies a drug deliversy system for protein and find the optimum preparation condition.Cross-linked alginate(Alg) microcapsule was used to prepare microcapsule for protein,using bovine serum album(BSA) as a model drug.Effect of different cations and content of protein on configuration,size and enveloped rate of microcapsule were investigated.It is shown that Ba-Alg microcapsule has steady configuration,homogeneous size and high-enveloped rate.Also electrophoresis of native BSA before microencapsulation and after microencapsulation is measured by(SDS-PAGE),it is found that no significant change is observed BSA integrity.Release of BSA from microcapsule in vitro presents sustained release in some extent,and initial burst effect is significantly obvious.Microenpsulation drug in alginate will be a wishful drug delivery system.     

Experimental Study of Multifunctional Acid to Deliquesce Stratum-jam

Aiming at the oneness of acid to deliquesce stratum-jam applied in scene at the present time,which is incapable of deliquescing complex dirty simultaneously,this article confects a new multifunctional O/W acid.This acid is an emulsified mixture containing 15% hydrochloric acid as its extro-posture,high dissolved oil as its internal state under the function of some proper exterior active reagent.It is composed of 0.5%OP-10,0.5%Span80,0.2%Tween80,0.06%imidazole and 0.01%twelve-alcohol,and the content of oil is equal to the acid content.It can be indicated that this acid has good ability of resolving mineral(CaCO_3,MgCO_3) and organic compound(mainly colloidal bitumen) when it was poured into the stratum,so that it can deliquesce oleic stratum-jam,resume and improve the penetrability of stratum,boost the ability of liquid flowing up.     

Calculating the Hollowing-center Grounding Device Resistance Based on the Surface Charge Simulation Method

An equivalent model for hollowing-center grounding device is proposed, the hollowing-center grounding device resistance is calculated with the surface charge simulation method and the computer programme is programmed based on this model. The accuracy of the model and method is validated by experimentation.     

Analysis of thermal stress in a water pipe of blast furnace copper stave

To solve the general problem that copper staves experience water pipe failure in blast furnace,the effects of constraints on the thermal stress distribution of copper stave water pipe are investigated by thermal-structural coupling analysis.In this study,a mathematical model of thermal stress of copper stave is established to analyze the thermal deformation and stress distribution of water pipe under subject to different types of constraints.The results show that the thermal stress on the root of water pipe is larger than others as the terminal of water pipe is free or being fixed.But the equivalent stress on the root of water pipe is just 45 MPa as the terminal of water pipe is free,which is lower than the yield strength of pure copper.The equivalent stress on the root of water pipe is about 272 MPa as the terminal of water pipe is being fixed,and exceeds the yield strength of pure copper.The water pipes should be flexible.The maximum equivalent stress is about 600 MPa as the water pipe is subjected to the constraint of shell,which is far beyond the yield strength of pure copper.The maximum displacement is located at the end of water pipe and is about 1.73 mm.Then the diameter of the hole should be 120 mm with taking installation error into consideration.     

Monitoring and Assessment of Tie on the Caiyuanba Yangtze Bridge

The monitoring and assessment scheme of the Caiyuanba Yangtze Bridge is present by sensitivity analysis. The mechanics character of the six ties is studied by numerical simulation, and then the sensor location and selection are discussed considering the technique of sensor and construction situation. The trend of the displacement at the sensor location is analyzed according to different damage level of ties, the pattern associating with several displacements which are sensitive to damage at ties is bring forward to improve assessment reliability. The result can assist implement of structural health monitoring system to the same type as this bridge.