控轧控冷工艺对高强度锚杆钢组织和性能的影响

随着矿井深度的增加,对锚杆支护强韧性的要求越来越高,为了应对这一情况,需要研发出更高强度的锚杆钢。利用锚杆钢研究了轧制工艺、冷却工艺与珠光体、铁素体相比例,析出相析出行为及力学性能的关系。研究结果表明,在中轧后、精轧前采用适当水冷+回复段处理的复合工艺可使晶粒更细小、组织更均匀。对超高强度锚杆钢进行热压缩变形试验,由热模拟试验结果确定相转变温度为A_c1=737 ℃、A_c3=886 ℃。最终筛选出入精轧温度为810 ℃、回复段温度为800 ℃时,可获得的晶粒尺寸达4 μm,珠光体体积分数为66.8%,铁素体体积分数为33.2%,珠光体片层间距达200 nm;另外调整V、Cr、N等析出以提高锚杆钢的强韧性,较低的回复温度有利于细小、弥散、V(C/N)析出相的析出,V(C/N)的析出可进一步改善锚杆钢的力学性能。由该控轧控冷工艺轧制的锚杆钢屈服强度为780 MPa、抗拉强度为930 MPa、硬度为291HV、伸长率为20%。     

300V以上硅基新型JBS肖特基二极管的制备

为了在保留传统肖特基二极管正向压降低、电流密度大优点的基础上,使其反向击穿电压提高到了300 v以上,我们采用硅材料做为衬底,肖特基结区采用蜂房结构,终端采用两道场限环结构加一道切断环结构,所制备的肖特基二极管在正向电流10A时,正向压降仅为0.79 V;同时在施加300 V反向电压时,反向漏电流在5μA以下.     

40000m~3/h空分设备变负荷操作及过程优化

主要探讨了冶金用制氧机组如何适应炼钢炼铁需求量的不断变化,减少氧气放散。通过对40000 m3/h制氧机组进行变负荷操作以及对操作过程的优化,实现了节能降耗、减少氧气放散的目的。     

一种基于FPGA的可变速率帧结构设计与实现

在简述V.35接口的基础上针对V.35接口速率可变的应用需求提出了一种速率可变的帧结构,该帧结构可支持N×64kb/s(3≤N≤32)速率,从而在V.35接口上实现了多种速率的低速业务传输.     

Linear friction welding of Ti6Al4V: experiments and modelling

Linear friction welding of the Ti6Al4V alloy is studied. A new definition of the energy input rate is proposed, based on an integration over time of the in-plane force and velocity; a strong correlation with the upset rate is then found. The effective friction coefficient is estimated to be 0·5±0·1 for varying frequencies and amplitudes, with only a weak dependence on the processing conditions displayed. A model is proposed that accounts for both the conditioning and equilibrium stages of the process, which is shown to be in good agreement with the experimental data. The model is used to study the mechanism by which the flash is formed. A criterion is proposed by which the rippled nature of its morphology can be predicted.     

Study on the disulfide bond and disulfide loop of native and mutated SOD1 protein

The superoxide anions in the human body are reduced into hydrogen peroxide and molecular oxygen by the metallo enzyme Cu–Zn superoxide dismutase 1. The disulfide bond in SOD1 is essential to maintain the structural stability of protein and its proper folding. A computational study on the disulfide bond with the addition of residues was made using three different level of theories viz., B3LYP/6-31G (d,p), M052X/6-31G (d,p) and MP2/6-31G (d,p). The nature of disulfide bond was found to be unaffected with the additional residues being attached to the termini of cysteine residues. This result was found to be in agreement with the experimental values. The results of Molecular Dynamics simulation illustrate the crinkled appearance caused in the disulfide loop of A4V mutation. The conformational change in the disulfide loop was found to have significant effect on the loss of dimerization, metal binding affinity and overall protein stability. It is also noted that the disulfide loop with more number of residues is found to have no effect on the disulfide bond characteristics, but the disulfide loop with less number of residues is found to have remarkable effect for mutation in any position of the wild type protein.     

Experimental investigation and thermodynamic calculation of the phase equilibria in the Fe–Ni–V system

The phase equilibria in the Fe–Ni–V ternary system were investigated by means of electron probe microanalysis (EPMA) and X-ray diffraction (XRD). Three isothermal sections of the Fe–Ni–V ternary system at 1000 °C, 1100 °C and 1200 °C were established. On the basis of the obtained experimental data, the phase equilibria in the Fe–Ni–V system were thermodynamically assessed using (CALculation of PHAse Diagrams) CALPHAD method, and a consistent set of thermodynamic parameters leading to reasonable agreement between the calculated results and experimental data was obtained.     

压铸模用钢3Cr2W8V热处理工艺改进及应用

基于压铸模用钢3Cr2W8V的成分及性能特点,分析了3Cr2W8V传统热处理工艺的不足.结合生产实践,对压铸模用钢3Cr2W8V的热处理工艺进行了改进,针对压铸模具的应用条件,提出了几种不同热处理工艺方案.经生产实践检验,改进后的热处理工艺方案合理、科学,具有经济性和应用价值.     

软件测试模型的探讨

软件测试是软件工程的一个阶段,也是保障软件质量必不可少的重要一环。软件测试模型是软件测试的工作框架,用于指导软件测试过程。本文在深入研究各种综合测试技术的基础上,通过对比分析各种主流的测试模型,提出了一种新的软件测试模型,包括静态测试、动态测试,测试评估等活动,把这些活动嵌入到软件开发的整个生命周期,能更好地规划软件开发和测试等一系列活动,提高了软件生产效率及其质量,该模型还适合于迭代开发。     

5G隧道环境非平稳宽带双散射簇V2V信道建模

针对5G隧道V2V通信环境,提出了一种通用的3D非平稳宽带双散射簇信道模型。在该模型中,接收信号为视距(line-of-sight,LOS)传播的分量和通过双散射簇模型传播即非视距(non-line-of-sight,NLOS)传播的分量之和。为了研究散射簇的非平稳特性,引入生灭过程算法来模拟散射簇在阵列和时间轴上的出现和消失过程。通过推导空间互相关函数、时间空间自相关函数和多普勒功率谱密度等相关统计特性,研究了散射簇的非平稳特性对MIMO信道的影响。数值仿真结果与先验结果较匹配,表明该模型能够较好地描述实际5G隧道环境下的V2V通信。