烧结计算配矿模型的设计与应用

针对目前烧结配矿的现状,提出了计算配矿模型结构;在计算配矿模型中,除了考虑化学成分外,还考虑到影响烧结过程的原料的粒度组成以及经济指标;采用VisualC++6.0开发了计算配矿模型软件,用户可以根据配矿实际情况.采用定配比法或线性规划法灵活进行混匀配矿计算,应用定配比法或简易理论配料法进行快速配料计算.该模型已在多个烧结试验中得到成功应用.     

基于电液反馈的轴向柱塞机械润滑试验系统

针对不同润滑介质轴向柱塞机械关键摩擦副润滑特性,研制了运用电液控制技术控制油膜形态的试验系统.介绍了该系统基于膜厚反馈控制的配流副装置试验原理及其组成.结合配流副润滑理论模型,指出评价润滑性能的主要参数及其关系,仿真计算了伺服阀对油膜厚度控制的响应特性.配流副油膜平衡过程中反馈调节特性的模拟试验与该理论结果进行了对比分析.油润滑条件下,摩擦副间隙对泄漏流量影响显著.试验系统的膜厚动态反馈性能稳定,比例伺服阀频响对其影响较大,随着初始平衡厚度值的不同而不同,该控制方法可用于润滑膜试验系统的设计.     

Microwave Absorption Properties of the Carbonyl Iron/EPDM Radar Absorbing Materials

Employing carbonyl iron powder and Ethylene-Propylene-Diene Monomer(EPDM)as the absorbent and matrix,rubber radar absorbing materials(RAM)were prepared.Effects of the carbonyl iron volume fraction and the thickness of the RAM on the microwave absorption properties in the frequency range of 2.6-18GHz were studied,and a mathematical analysis was made using the electromagnetic theory. The experimental results indicate that the minimum reflectivity of the radar absorbing materials continuously decreases with the increase of the carbonyl iron volume fraction,and the absorption peak also moves towards the low frequency for the same thickness of the RAM.The minimum reflectivity of the 3.0 mm RAM is -21.7dB at 3.5 GHz when the volume fraction of carbonyl iron is 45%.The reflectivity of the RAM is not in direct proportional to the thickness of the RAM,when the RAM has the same volume fraction of the carbonyl iron.The reflectivity of the RAM presents a regular trend at a given carbonyl iron volume fraction in the frequency range of 2.6-18 GHz.With the increase of the thickness,the maximum absorption peak moves towards low frequency band,the minimum reflectivity firstly decreases and then increases,and the absorption bandwidth for reflectivity<-10 dB firstly increases and then decreases.The microwave absorption properties of the RAM are determined by the thickness and the composition of the radar absorbing materials. Theoretical analysis indicates that the reflectivity of the RAM is determined by the matching degree of the air’s characteristic impedance and the input impedance.     

Behavior of oxygen in DG? invar-Cu alloys and its effects on mechanical and physical properties

The invar alloy powder, mixed with different Cu powder contained different content of oxygen, was compacted and sintered into four sorts of DG™ invar-Cu low expansion and high conductivity alloy specimens. The mechanical and physical properties of the alloys were tested and analyzed. The behavior of oxygen and its effect mechanism were discussed. The results show that the ultimate strength decreases with the increase of oxygen content, so does the coefficient of thermal expansion (α) whereas the α platform is shortened. Project supported by the Natural Science Foundation of Hunan Province Synopsis of the first author Wang Zhifa, Senior Engineer, born in 1946, specializing in electronic packing materials. His studied group developed the first W disc and the first invar-Cu plate of the country for power semiconductor devices.     

Effect of heat treatments on tensile properties and microstructure of 2195 alloy

Effect of various aging treatments on the tensile properties and microstructure of 2195 alloy has been investigated. The experimental results show that promising combination of strength and ductility is achievable under T₈ temper. The lower aging temperature reduces T₁ precipitation on the subgrain or grain boundaries and favors uniform dispersion of T₁ phases in the matrix, resulting in better strength and ductility. Prior deformation before aging has improved tensile strength with a slight decrease in ductility. Pre-aging after prior deformation had little effect on the age-hardening behavior of 2195 alloy. Project supported by the Key Program of the 9th Five-year Plan of China Synopsis of the first author Zheng Ziqiao, professor, born in 1944, major research fields: physical metallurgy of aluminum alloys; functionally gradient materials; self-propagation high temperature synthesis.     

铸态QT550-7球墨铸铁制备及组织研究

为了研究铸态QT550-7球墨铸铁组织,铁液凝固过程及石墨球化机理,用回炉铁、生铁、废碳钢、球化剂、孕育剂等材料,采用双联熔炼法制备了球墨铸铁.经测试,化学成分和力学性能满足QT550-7球墨铸铁要求,球墨铸铁组织由铁素体＋珠光体＋球状石墨组成,凝固过程为糊状凝固.     

非晶态合金铁心变压器的试验研究

非晶态软磁合金是一种具有优异性能的新型材料,本文在实践的基础上,介绍了钴基、铁镍基、铁基非晶态软磁合金带的在分,制备方法,介绍了非晶态铁心的制备方法及热处理工艺。并通过研制的非晶态铁心电源变压器,脉冲变压器与传统磁性材料铁心电源变压器,脉冲变压器的应用对比试验,证明了非晶态软磁合金材料的高饱和磁感、低损耗性能及高导磁率,宽频幅工作性能。     

发动机润滑油理化指标与介电常数关系分析

通过实验检测电容传感器电容值的变化,验证了润滑油中水含量、铁含量和总酸值的变化量与润滑油介电常数增值之间的数量关系。结果表明:随着润滑油含水、总酸值、含铁的增加,润滑油介电常数变化趋势一致;对润滑油介电常数变化影响最大的是含水量;用介电常数作为评价润滑油衰变程度的综合指标在理论上是可行的。     

畸变图像的有效配准算法

镜头畸变是导致图像质量降低的主要因素之一.通常在图像存在畸变情况时,要先通过图像畸变校正方法来减小畸变对图像的影响,但校正过程较为复杂.本文提出了一种新的畸变图像的有效配准算法,算法分为初始匹配和松弛优化匹配两步,初始匹配算法采用圆投影匹配算法,松弛匹配算法则以向量旋转角的旋转和缩放不变性特征作为初始匹配对的优化准则,首先计算向量旋转角度差值,然后通过构造支持度函数和剔除策略选出最优匹配对.实验证明,该算法在图像非线性畸变误差较大的情况下也能够实现正确匹配.     

基于FEM的足尺落地式浅圆钢筒仓静态贮料作用分析

准确计算贮料对仓壁的作用,是大直径浅圆钢筒仓安全设计的前提.为此,采用有限单元法(FEM)对足尺落地式浅圆钢筒仓的静态贮料作用进行了数值模拟分析,包括小麦、铁矿石散粒、石英砂和水泥散料,其本构关系服从Drucker-Prager屈服非关联流动准则.采用3-D模型同时模拟了贮料和筒仓,建立考虑变形的面-面接触对,以更好地反映贮料对仓壁的静态作用.将FEM模拟值与国内外筒仓规范的计算结果进行了对比分析,并讨论了贮料力学参数的影响,表明FEM可作为一种准确、可靠的钢筒仓静态贮料作用计算工具.     

Cu及Cu-Zn合金压缩行为机理的研究

通过Cu及Cu-Zn合金的压缩实验,分析了不同层错能Cu及Cu-Zn合金的压缩真应力-真应变曲线,提出把Cu及Cu-Zn合金加工硬化行为以0.1的应变量为界点分为两个不同的阶段.0.1应变量之前的材料强化机理很复杂,主要受孪生、固溶强化、有序强化、位错胞等的综合影响,使得Cu、Cu-10%Zn、Cu-20%Zn和Cu-30%Zn的强度在0.1应变量前依次递减.当应变量超过0.1,材料的强化机制主要包括细晶强化与变形孪晶强化,随着层错能的降低材料的强塑性提高.本实验详细研究了Cu及Cu-Zn合金加工硬化行为及微结构演变机理,为更好地了解超细晶材料的机械变形行为以及提高材料强塑性提供参考.     

搅拌摩擦焊研究最新进展

搅拌摩擦焊(Friction Stir Welding．简称FSW)是一种新型固相连接工艺．它不仅能实现其他连接方式能够实现的接头，且能实现在熔焊条件下焊接性能差、易产生焊接缺陷的材料的连接，如高强铝合金、铝锂合金，使焊接接头的性能大大提高．本文分析了近年来搅拌摩擦焊技术的发展和最新进展，涉及搅拌摩擦焊机理即塑性流体运动情况适用母材、力学性能和焊接工具．     

过共晶铝硅合金中锰含量对合金性能的影响

研究了在Al-22%Si合金中分别加入1%Fe、0.76%Mn和1%Fe、1.50Mn对合金有关性能的影响.用测定合金的冷却曲线的方法,了解和比较了Mn量对合金凝固温度区间大小的作用;测定了不同Mn量合金的线膨胀系数,了解了Mn量对线膨胀系数的影响.研究结果表明,加入Fe、Mn后以及提高锰量,合金的凝固温度区间变窄;线膨胀系数减小.     

基于特征匹配的三维点云粗配准方法

针对无初值情况下点云配准精度不高以及配准效率低下的问题,提出一种基于特征匹配的三维点云粗配准方法。首先,利用点云局部法向量的变化描述其特征,加入特征保留权值筛选突出特征信息,提高配准效率;然后,根据保留的特征信息建立特征直方图,通过比较特征直方图描述的信息获取初始匹配的点对;最后,将刚性不变约束与随机抽样一致性算法结合筛选正确的匹配点对,再利用四元素法得到旋转矩阵和平移向量。实验结果表明,提出的算法与其他粗配准算法相比具有较高的精度和效率,为后续的点云精配准工作提供了良好的初值。     

修正型圆环面包络环面蜗杆减速器的试验分析与性能评价

本文综合修正型圆型环面包络环面蜗杆融的理论研究成果和性能试验数据，全面验证了该型蜗杆融继ＺＡ、ＺＣ、ＴＡ、ＴＰ、ＴＫ型蜗杆副之后出现的又一种具尼曼齿形的新型的高效蜗杆融。     

加入高分子聚合物添加剂的国产润滑油与固体界面性质的研究

本文对添加不同百分比聚甲基丙烯酸酯和聚异丁烯的30~#机械油,用圆锥最大拉力法测定其表面张力。根据所得数据用回归方程导得表面张力与湿度和润滑油浓度三者之间的关系。利用获得的表面张力数据,并假定润滑油分子之间以及润滑油和固体,包括铜、铁石墨和聚四氟乙烯界面分子之间的作用力只是色散力,结合有关的文献数据,估算了接触角θ,附着功W_A~(SLV)和吸附焓(?)αH等液-固参数。根据这些参数变化,讨论了润滑剂在固体表面上形成吸附膜的性质,以探讨非牛顿流体的润滑机理     

Electrical Breakdown Characteristic of Nanostructured W-Cu Contacts Materials

Nanostructured （ NS ）W-Cu composite powder was prepared by mechanical alloying （ MA ）, and nanostructared bulk of W-Cu contact material was fabricated by hot press sintering in an electrical vacuum furnace. The rnicrostructure, electric conductivity, hardness and break down voltage of NS W- Cu alloys were measured and compared to those of conventional W-Cu alloys prepared by powder metallurg＇y. The experimental results show that microstructural refinement and uniformity can improve the breakdown behavior and the electric arc stability of nanostructared W- Cu contacts materials. Also, the wanostructured W- Cu contact material shows the characteristic of spreading electric arcs, which is of benefit to electric arc erosion.     

基于密集连接网络和多维特征融合的文本匹配模型

针对文本匹配过程中存在语义损失和句子对间信息交互不充分的问题,提出基于密集连接网络和多维特征融合的文本匹配方法. 模型的编码端使用BiLSTM网络对句子进行编码,获取句子的上下文语义特征;密集连接网络将最底层的词嵌入特征和最高层的密集模块特征连接,丰富句子的语义特征;基于注意力机制单词级的信息交互,将句子对间的相似性特征、差异性特征和关键性特征进行多维特征融合,使模型捕获更多句子对间的语义关系. 在4个基准数据集上对模型进行评估,与其他强基准模型相比,所提模型的文本匹配准确率显著提升,准确率分别提高0.3%、0.3%、0.6%和1.81%. 在释义识别Quora数据集上的有效性验证实验结果表明,所提方法对句子语义相似度具有精准的匹配效果.     

用镁—钛—稀土合金制造紧密(蠕虫)石墨铸铁的试验研究

本文叙述了用单一中间合金生产紧密(蠕虫状)石墨铸铁的研究工作,研制出了可使含硫量为0.04％及0.07％的原铁水稳定地生产出紧密石墨铸铁的蠕化剂合金,讨论了单一蠕化剂合金中某些元素对蠕墨铸铁的影响,并研究了蠕墨铸铁的铸造能。     

Application of the C-Me segregating theory in solid alloys to ceramics

Because of its excellent properties, zirconia ceramics has already been widely applied. Its phase transformation affects its properties. The research on the mechanism of its phase transformation is very important to control the phase transformation as well as its properties. The valence electron structure of cubic zirconia, tetragonal zirconia and monoclinic zirconia are calculated with the em-pirical electron theory in solids and molecules in this paper. The results show that the total numbers of the covalent electron pairs which form their strong bond framework are 3.19184, 3.45528 and 3.79625, respectively. According to the view-point of the C-Me segregating theory in solid alloys, it can be deduced that the phase transformation order of zirconia should be liquid phase→cubic phase→tetragonal phase→monoclinic phase. The deduction from valence electron struc-ture is completely in accordance with the experimental results, so the electron theory of phase transformation in alloys can be expanded to ceramics materials.