提高1#连铸机至二棒轧线方坯热送率的工艺实践

通过对炼、轧钢工序开展工艺、设备、参数优化、生产组织等攻关工作,将连铸坯矫直温度提高到了1070℃以上,减少了铸坯在运输过程中的热损失,确保了铸坯进入加热炉时的温度达到850℃,综合铸坯热送热装率平均达到了64.4%,最高达到了80%的设定目标,使吨钢煤气用量得到降低,取得了一定的效果。     

Learning curve analysis of concentrated photovoltaic systems

Price declines and volume growth of concentrated photovoltaic (CPV) systems are analysed using the learning curve methodology and compared with other forms of solar electricity generation. Logarithmic regression analysis determines a learning rate of 18% for CPV systems with 90% confidence of that rate being between 14 and 22%, which is higher than the learning rates of other solar generation systems (11% for CSP and 12 to 14% for PV). Current CPV system prices are competitive with PV and CSP, which, when combined with the higher learning rate, indicates that CPV is likely to further improve its marketability. A target price of 1 $/W in 2020 could be achieved with a compound growth rate of 67% for the total deployed volume between 2014 and 2020, which would realize a cumulative deployed volume of 7900 MW. Other projections of deployment volumes from commercial sources are converted using the learning rate into future price scenarios, resulting in predicted prices in the range of 1.1 to 1.3 $/W in 2020. © 2014 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd.     

MATERIAL MODELLING FOR TRANSIENT DYNAMIC ANALYSIS OF REINFORCED CONCRETE STRUCTURES

Reinforced concrete is a composite structural material which has been the subject of extensive research since it was first used. When considering the rational properties, the research has mainly centred on the behaviour of the concrete, that of the reinforcing steel and the interaction between the steel and the surrounding concrete subject to static loading. The behaviour of reinforced concrete, and, in particular, that of the concrete itself when subject to dynamic loading has been less thoroughly studied. This paper proposes a material model for the concrete which includes the effect of high strain rate upon both the stiffness of the material and upon the crushing strength. It proposes expressions for the yield and failure surfaces of the concrete which account for the effects of high strain rate and then incorporates this material model into an existing finite element program to compare with a series of test results. The paper illustrates that this improved material model can now produce a displacement/time history for reinforced concrete elements which is very close to that observed in tests on elements which are far outside the elastic range.     

5CrMnMo应变率和温度相关力学性能实验研究

在较大的温度(25℃-537℃)和应变率(10-4s-1-10-2s-1)范围内对5CrMnMo进行了拉伸实验,获得了相应的应力应变曲线.试验结果表明在室温和试验的应变率范围内(10-4s-1-10-2s-1),5CrMnMo的力学性能是应变率无关的.随着温度的升高,出现了模量E、屈服强度σs和抗拉强度σb的应变率强化效应和温度弱化效应;还出现了加工硬化倾向减小的机制和蠕变效应增大机制,且温度越高这两种机制越强,应变率越高这两种机制越弱.在这两种机制作用下,温度越高失稳应变εb越小,断后伸长率δ50越大;但应变率越高δ50越小.当试验温度较高且应变率较低时,伴随有马氏体板条向拉伸方向偏转的细观特征.     

Saturation swelling and the seeded emulsion polymerisation of styrene at high ionic strength

The effects of adding inorganic electrolyte (below the critical coagulation concentration) have been investigated in two systems for the emulsion polymerisation of styrene. In one system, potassium chloride, at different concentrations, was added at the end of interval I, using three different ionic emulsifiers: potassium octadecanoate which has a low critical micelle concentration (CMC), potassium dodecanoate and sodium dodecyl sulphate (SDS), which have moderately high CMC. A significant increase in the rate of polymerisation was observed in all cases even at the higher levels of electrolyte at which the rate is reduced if the electrolyte is added from the onset of polymerisation. In the second system, the effects of adding sodium chloride, in concentrations up to 0.2_M, on the seeded emulsion polymerisation of styrene have been followed. A significant increase in the rate was observed as electrolyte level was increased, with no significant change in particle size. Saturation swelling measurements indicated a slight increase in monomer concentration inside the particles as electrolyte concentration was increased. Evaluation of the average number of free radicals per particle, n¯, by a steady state approach indicates an increase in the value of n¯ as electrolyte level is increased. The value of n¯ is below 0.5 but approaches this value at the highest electrolyte concentration. The increased surface area of the particles may account for this effect by increasing the capture efficiency of the radicals by the particles.     

SWAN模型速率控制模块性能分析及改进

SWAN是Ad Hoe网络中的一种无状态网络协议,利用分布式控制算法来传递分类服务。这种QoS模型把数据业务分为两类进行不同处理,即对尽力而为的UDP和TCP业务采用速率控制的策略而对实时的UDP业务采用基于源节点的接纳控制策略。本文修改了SWAN模型的速率控制模块,引入队列调度机制,对从上层来的尽力而为数据包进行排队、调度,使其尽可能公平地占用新到资源。在分析中具体给出了修改后速率控制模块的实现过程。通过仿真分析了AIMD算法的参数对修改后速率控制模块性能的影响。     

Ni-MH蓄电池自放电规律及其应用

探讨了MH-Ni蓄电池的自放电变化规律及其在电池筛选方面的应用。MH-Ni蓄电池的自放电率随搁置时间的增加而增大,但增大幅度逐渐变小。其25℃下的变化规律可拟合为Boltzmann函数;蓄电池的自放电率随环境温度的增大而增大;极板表面积影响电池的自放电,搁置初期,电池自放电随极板表面积增大而降低,搁置后期(10～28d),电池自放电随极板表面积增大而增大。电池开路电压越低,其自放电越大。此外,MH-Ni蓄电池自放电率的一致性对循环寿命也有影响,同等条件下,自放电差异小的电池组,其循环寿命优于随机组合的电池组。     

全低压正流膨胀小型空分设备开发中的技术探讨

对全低压正流膨胀小型空分设备(KDON-180/350型)的流程特点和研制开发过程中各参数间关系进行了探讨。提出了如何减少膨胀空气量的方法。在加工空气压力为0.7 MPa(G)、膨胀量与加工空气量之比为25%的情况下,使氧的提取率达到85%~90%。并在全低压小型空分设备上成功地实现了内压缩和多种变工况流程,这是我国在小型空分设备技术上的又一次突破。     

基于响应面分析法优化冷榨花生油酸法脱胶工艺

本实验以冷榨花生油为原料,选择磷酸作为脱胶用酸,探索酸的添加量、水的添加量、脱胶温度和脱胶时间这4个实验因素和两两实验因素间的交互作用对冷榨花生油酸法脱胶率的影响.结果表明:对酸法脱胶率影响最显著的是酸的添加量,而水的添加量、脱胶温度和脱胶时间对于脱胶率的影响并没有那么显著.利用响应面优化酸法脱胶的工艺条件,得出当酸的...     

电流阀值对断续骚扰检测结果的影响

对于某些由开关操作数得出喀呖声率的被测设备,目前大部分检测实验室的断续骚扰分析仪可能会漏计算一些开关操作。解释了标准中"开关操作"的定义,通过实际案例阐述了使用分析仪进行断续骚扰项目检测时,预置电流阀值的选择对检测结果的影响。