Interface microstructure and reaction in Gr/Al metal matrix composites

The interface structure in Gr/Al composites fabricated with liquid metal infiltration has been studied using transmission electron microscopy (TEM). Morphologies of interfacial reaction product, aluminium carbide Al₄C₃, formed at different manufacturing parameters were compared and, the growth mechanism of the carbide was studied by means of high resolution electron microscopy (HREM). It has been shown that the morphology of the carbide is intimately related to the processing parameters with which the composites were produced. There are two kinds of interfaces between the carbide and the aluminium matrix. They have different growth mechanisms and relative growth rates under different growth driving forces. Several crystal orientation relationships between the carbide and the aluminium matrix have been observed.     

Electrochemical Investigation on the Formation of Dy-Fe Alloy in Molten Chlorides

ＥｌｅｃｔｒｏｃｈｅｍｉｃａｌＩｎｖｅｓｔｉｇａｔｉｏｎｏｎｔｈｅＦｏｒｍａｔｉｏｎｏｆＤｙＦｅＡｌｏｙｉｎＭｏｌｔｅｎＣｈｌｏｒｉｄｅｓＬｉｕＧｕａｎｋｕｎ（刘冠昆），ＴｏｎｇＹｅｘｉａｎｇ（童叶翔），ＨｏｎｇＨｕｉｃｈａｎ（洪惠婵），Ｙａｎｇ...     

液体火箭发动机研制情况的一些回顾

４０年来，我国液体火箭发动机的研制工作取得了很大成绩。文中对发动机的一些研制情况作了回顾，对ＹＦ－７３和ＹＦ－７５氢氧发动机的设计特点、飞行结果作了简单叙述。对今后工作也提出了看法。     

MPC系统模块结构中的流场研究

本研究中,应用Simple数值计算方法开发了求解MPC系统模块结构中二维流场分布的计算软件。为了验证计算结果的精确性,用多普勒测速仪实测了用有机玻璃制成的MPC模块二维模型的流场,模拟计算结果与实测值对比取得了较好的一致性。四种不同流出角的MPC模块平均总压损失计算结果表明,已开发的软件可作为设计低流阻MPC模块的良好工具。     

软土地基地下结构的一个CAD软件

本文介绍地下结构计算机辅助设计软件——UCAD的总体结构、主要功能以及解决的问题。     

SISAK快速化学分离装置的建立

SISAK(Short-lived Isotopes Studies by the AKUFVE technique)技术是目前使用最广泛的快速化学分离方法之一,主要应用在短寿命核素的分离和鉴别、超重元素的人工合成以及化学性质研究等方面的工作中.本文简单地叙述了SISAK技术的流程、原理和发展现状,介绍了自行建立的国内第一套基于SISAK技术的快速化学分离装置,并通过从裂变产物中分离短寿命核素这一实例验证了SISAK技术在快速化学分离中的优越性.     

Effects of interstitial oxygen on microstructure and mechanical properties of Ti-48Al-2Cr-2Nb with fully lamellar and duplex microstructures

The effect of added oxygen in the range of 1000 to 4000 wt ppm on the microstructures of a Ti-48Al-2Cr-2Nb alloy has been investigated and compared to the microstructures for a high-purity alloy. For specimens cooled from theα phase, interstitial oxygen stabilizes the lamellar microstructure with respect toγ grains, with higher than equilibrium values for theα ₂ volume fraction. For specimens cooled from theα +γ phase field, the lamellar microstructure still tends to be favored by oxygen, but it is found that the phase volume fractions are not significantly different from equilibrium values. This suggests that interstitial O essentially reduces the kinetics of theα toα +γ transformation. Thus, interstitial oxygen will have a strong effect on microstructures obtained by continuous cooling fromα, but significantly less on those, such as the duplex microstructure, obtained by long treatment in theα +γ phase field. In general, increased O content is well correlated with reduced ductility. Finally, the role of interstitial oxygen on this phase transformation is discussed.     

催化主风机故障分析与处理

主风机发生喘振后流量减小并且振动增大,抢修后振动未消除反而增加,且有上升趋势.运用状态监测方法对其测试分析,查出振源为动不平衡和对中不良.为使机组能继续安全运行,采取了加强监测,降低轴系负荷和降低润滑油油温等措施,故障消除.     

Synteny mapping of four genes from the short arm of human chromosome 19 to bovine chromosome 7

Four genes on the short arm of human chromosome 19 (HSA 19p) were assigned to bovine chromosome 7 (BTA 7) using a bovine x rodent somatic hybrid cell panel. These four genes were cartilage oligomeric matrix protein (COMP), lymphoblastic leukemia derived sequence 1 (LYL1), lysosomal alpha-mannosidase (MANB), and RAS oncogene family member RAB3A. Bovine sequence tagged sites were developed for the four genes and used for screening a bovine x rodent somatic cell panel. All four genes were mapped to bovine synteny group U22 (BTA 7) with a correlation coefficient of 0.901-1.000. This study confirms that the centromeric region of BTA 7 is conserved with HSA 19p.     

轮式工程机械的行驶平稳性

根据振动理论建立了振动力学模型,并用等效刚度方法分析研究了弹性悬挂轮式工程机械行驶平稳性和振动特性。