装备需求论证模式研究

针对当前装备需求论证(equipment requirement demonstration,ERD)领域内,关于论证模式的多种认识之间存在着矛盾性、模糊性等问题,在明确界定了装备需求论证活动边界问题的基础上,提出论证模式应分为需求获取、需求分析、方案拟制、方案验证、需求确认5个环节,详细阐述了5个环节各自的输入输出、主要任务等内容,分析了各环节之间的逻辑关系,说明了此需求论证模式符合装备需求论证工作的实际,能够适应装备需求论证领域内各层次论证活动的需要.     

碳纳米管复合镀层的界面结合

在锡铅合金基体上制备了碳纳米管镍基复合镀层,并利用水浴加热熔化基体的方法,成功制备出碳纳米管镍基复合镀层结合界面试样.采用场发射扫描电镜分析了复合镀层的表面和初始界面上的碳纳米管存在形式和分布.结果表明:碳纳米管可以部分直接沉积在初始界面,部分碳纳米管嵌入镍基镀层中.碳纳米管的有效嵌入镍基镀层有利于增强复合镀层的界面结合.     

一个含有二氢-二(N-甲基-2-巯基咪唑)硼酸盐配体的钌-苯肼阳离子配合物的合成、晶体结构与密度泛函理论计算(英文)

以四氢呋喃(THF)作溶剂,将[Ru(PPh3)3Cl2]与等摩尔的K[H2B(timMe)2]和过量的苯肼(PhNHNH2)反应,得到1个阳离子配合物[Ru(PPh3){κ3-H,S,S’-H2B(timMe)2}(PhNHNH2)2]Cl·0.5CH2Cl2(1)。单晶X-射线衍射分析显示,配合物1中的中心钌原子与三齿螯合配体[H2B(timMe)2](κ3-H,S,S’)、1个三苯基膦(PPh3)、2个顺式cisPhNHNH2配位形成1个八面体几何构型。通过密度泛函理论计算的价键分析,可确定配合物1中HOMO和LUMO间的能隙较窄,只有3.62 eV。     

浇注料在不同加热过程中的弹性模量变化

为了研究浇注料烘烤过程中其内部状态变化与其弹性模量变化的相关性,将纯铝酸钙水泥结合的刚玉质浇注料振动成型,自然养护24 h后脱模,部分脱模后试样继续在烘箱中于110℃干燥48 h,部分干燥后试样继续在500℃热处理3 h,采用弯曲共振法检测试样在不同加热过程中的弹性模量变化:1)对脱模后试样,以5℃·min-1的速率升温,并在50℃及其整数倍温度点保温60~90 min,检测试样在加热过程中的弹性模量变化;2)对干燥后试样,以5℃·min-1的速率连续升温至500℃,检测试样在加热过程中的弹性模量变化;3)对500℃热处理后试样,以15℃·min-1的速率连续升温至500℃后保温35 min,检测试样在保温过程中的弹性模量变化。结果表明:1)自由水的排出使试样的弹性模量增大,结合水的排出则使其弹性模量减小;2)在连续升温的加热过程中,自由水和结合水的排出滞后于设置保温的加热过程,试样弹性模量的变化也出现相应的滞后现象;3)快速连续升温过程中试样内部存在热应力,温度和热应力的存在会影响试样的弹性模量;4)浇注料烘烤过程中弹性模量的变化可综合反映其内部状态变化尤其是水分排出情况的变化。     

DT4钢循环热处理后的组织及扭转性能

为满足DT4钢在汽车限力轴上的应用要求,对其进行循环热处理,研究热处理后材料的组织与扭转性能。结果表明,经2次循环退火处理后,DT4钢平均晶粒尺寸为12.50 μm,约有65.0%的晶粒在12.93 μm左右,10 μm以下的晶粒增多,晶粒细化明显且均匀性提高,扭转强度增加10.31%,剪切屈服强度增加7.53%。     

The electromagnetic properties of the Mn doped Ge/Si quantum dots diodes

We present the electromagnetic properties of Mn doped Ge quantum dots (QDs)/Si electromagnetic diode. The Ge:Mn QDs were grown with a GeH₄/Ar mixed gas under a constant flow at 500 °C by means of a plasma enhanced chemical vapor deposition (PECVD) process. They were then doped with different concentrations of Mn using a magnetron sputtering technique and annealed at 600 °C. The Ge:Mn QD samples show wildly open smooth hysteresis loops. The remnant magnetization M_r and saturation magnetic intensity M_s are functions of the doping concentration of Mn. The electromagnetic diodes fabricated in this way exhibit perfect electromagnetic, current–voltage (I–V) and capacitance–voltage (C–V) properties. The largest voltage and magnetic resistance differences with and without magnetic field are up to 4 V and 169 kΩ, respectively. These electromagnetic properties of the Ge_1?xMn_x QDs/Si diodes can be used to make various electromagnetic devices, including switches and storages devices.     

Internal Stress of Dense Refractory Castables During Unilateral Heating

The change of the internal stress of dense refractory castables during unilateral rapid heating was studied by the electric stress measurement. The results indicate that:(1) during rapid heating,the position near the heated surface is under compressive stress; the closer the position to the heated surface,the larger the compressive stress;(2) the specimen bursts during the rapid heating;(3)the calculated stress of the structure at the burst moment shows that the compressive stress produced at the same depth as the cracking surface exceeds the ultimate strength of the structure.     

Experimental-based optimization of polymer injection molding process parameters using anfis-ga method

Compared with ordinary injection-molded parts, the slender, cantilevered, and thin-walled plastic parts are harsh on the injection molding process conditions. For complexity and particularity, it is difficult to form such parts. It is also more likely to cause excessive warpage deformation, affecting the molding quality and performance. The automobile audio shell is a typical slender, cantilevered, thin-walled plastic part. When the mold structure and material are determined, optimizing its injection molding process is the most economical and effective method to manufacture the products with the optimum properties. In order to minimize the warpage deformation, the adaptive network based fuzzy inference system (ANFIS) and genetic algorithm (GA) were adopted to optimize the injection molding process parameters. In particular, considering the high-dimensional nonlinear relationship between the process parameters and the warpage, the ANFIS is constructed as the prediction model of the warpage. Then, the GA is used to globally optimize the prediction model to determine the optimal process parameters. The results show that the optimization method based on ANFIS-GA has a good performance. The warpage is reduced to 0.0925 mm while reduced by 88.25 %. The optimal injection molding process parameters are used for simulation and manufacture, verifying the effectiveness and reliability of the optimization method.

     

汽车安全带系统的新近进展

安全带系统是保证乘员安全的重要装置。主要分析安全带的保护机理,对目前安全带的种类及其性能进行了分析对比。最后对未来安全带系统的发展趋势作了展望。