Deformation induced Nanostructure and texture in MP35N alloys

The macro-texture was related to the nano-platelets formed during the rolling deformation of a Co-Ni-Cr-Mo alloy (MP35N) with low stacking fault energy. The deformed materials showed {011}(533) texture but also had {011}(211) and {011}(100) texture components. The {011}(533) component reached the maximum at 74% reduction-in-area. Further deformation of the material to 80% decreased the intensity of the {011}(533) component. The cold deformation introduced platelets of a few atomic layer in thickness and less than 100 nm in diameters. The habit planes of the platelets were identified to be {111}, which were perpendicular to both the rolling and {011} crystallographic plane. Therefore, the tensile strain in the rolling direction assisted formation of the platelets, which were identified as stacking faults. A high density of nano-platelets and dislocations strengthened materials and influenced the plastic deformation behaviors and texture evolution. Thus, the MP35N developed slightly different textures from other low stacking fault energy materials. The maximum at {011}(533) was related the nanoplatelets and stacking fault energy. The {011}(112) and {110}(001)components could be linked to the low stacking fault energy.     

Rod-like β-FeSi2 phase grown on Si (111) substrate

Pure Fe with coverage of 0.5-2.0 nm was deposited on Si (111) 7×7 surfaces by reactive deposition epitaxy (RDE) in an integrated ultrahigh vacuum (UHV) system. Transmission electron microscopy (TEM) confirmed that the as-deposited epitaxial phase exhibits rod-like and equilateral triangular morphology. The as-deposited phase was identified as c-FeSi₂ by electron diffraction and high-resolution transmission electron microscopy. It was found that there exists lattice distortion in epitaxial c-FeSi₂ phase. Upon annealing at 1073 K, the metastable c-FeSi₂ transforms into equilibrium β-FeSi₂ phase, the latter inherits completely the morphology of c-FeSi₂ phase. Based on RDE and subsequent annealing, a new fabrication technique to grow rod-like semiconducting β-FeSi₂ on a Si substrate has been proposed in the present work.     

新课程理念下师生互动物理教学策略

互动教学是一种动态的教学过程,通过教学中的互动使师生成为一个“学习共同体”。互动教学须把学习目的作为教学设计的依据和归宿;须让学生参与有实际意义的交流。     

Effects of surface treatment of field emitter arrays on electrical characteristics of active matrix cathode

The effects of a wet chemical surface treatment of molybdenum-tip (Mo-tip) emitters on the electrical characteristics of an active matrix cathode composed of hydrogenated amorphous silicon thin film transistors and Mo-tip emitters are described. X-Ray photoelectron spectroscopy measurements showed that the surface treatment removed MoO₃ from the surface of the e-beam evaporated Mo film. In addition, the surface roughness of the Mo film was increased as the result of the surface treatment. The surface-treated active matrix cathode showed stable emission characteristics and immunity from emitter failures during its operation. The response time of the active matrix cathode was decreased by the surface treatment of the Mo-tip emitters. A change in surface composition and surface roughness appear to be responsible for the enhancement of the active matrix cathode.     

A method for testing interlaminar dynamic fracture toughness of polymeric composites

Static and dynamic Mode I delamination fracture in two polymeric fiber composites was studied using a WIF test method. The dynamic test was conducted on a Split Hopkinson Pressure Bar apparatus. Crack speeds up to 1000 m/s were achieved. Dynamic fracture and crack propagation were modeled by the finite element method. Dynamic initiation fracture toughness of S2/8552 and IM7/977-3 composites were obtained. The dynamic fracture toughness of IM7/977-3 associated with the high speed propagating crack was extracted from the finite element simulation based on the measured data. It was found that the dynamic fracture toughness of the delamination crack propagating at a speed up to 1000 m/s approximately equals the static fracture toughness.     

Factors Affecting Flow-Mediated Vasodilatation in Hemodialysis Patients

Clinical manifestation of overt vascular disease may be preceded for years by endothelial dysfunction. Objective: This study was undertaken to evaluate endothelial function in ESRD patients and correlation between endothelial function and clinical and biochemical parameters. Methods: 32 stable ESRD patients (male : female = 16 : 16, average age: 55.2 ± 13.0) on hemodialysis were included. A 10‐MHz ultrasound transducer was used to image the brachial artery. Brachial artery diameter was measured, and reactive hyperemia was induced by inflation to 250 mmHg for 5 min and then deflation of a pneumatic cuff. After release of the cuff, brachial artery diameter was measured. Results: In the entire study population and non‐diabetic group, the %FMD (% flow‐mediated dilatation, % change of brachial artery diameter between before and after cuff inflation) did not show any significant correlation with duration of dialysis, age, hypertension, albumin, CRP, total cholesterol, LDL and HDL cholesterol, and triglyceride. However, the %FMD of diabetic patients was lower than that of non‐diabetics. Among the patients with diabetes, the group of patients with FMD of <5.2% showed significant lower serum albumin and significantly higher ln(CRP) levels compared to the group of patients with FMD ≥5.2%. The %FMD showed significant positive correlation with serum albumin level and significant negative correlation with ln(CRP) in diabetic patients. Conclusion: These findings suggest that endothelial dysfunction, estimated by FMD, was significantly more prominent in diabetic ESRD, especially with low serum albumin and high CRP levels.     

装甲车舱室内有害气体浓度吸收光谱法测量

多数装甲自行武器车体舱室内的武器弹药在运输、储存和使用过程中会产生许多有毒有害气体,需要对其进行检测.介绍了吸收光谱法测量车体内有害气体的基本原理,研制了能同时测量二氧化硫等多种气体的装置,建立了对多种被测气体浓度同时进行反演的数据处理方法.该方法能现场实时测量车体内中有毒有害气体的浓度,不需要采样.测试仪器操作简单、工作稳定.     

钎焊时压力载荷对金刚石接头残余应力的影响

针对金刚石与其他材料连接时接头处容易产生较大的应力而导致接头连接强度下降的问题，采用Marc有限元分析方法，模拟了用Ag—Cu—Ti钎料钎焊金刚石与硬质合金接头的应力分布情况，研究了试件在钎焊过程加载和不加载时对应力分布的影响．结果表明，对试件施加一定的裁荷比未加载荷时接头的最大残余应力值小，且模拟结果具有较高的准确性，为确定实际工艺参数提供了依据．     

预制挑檐的几种构造作法

挑檐是建筑屋面的一个组成部分。本文介绍了挑檐自重平衡法、屋面板压重平衡法、圈梁压重平衡法、螺栓锚固法等四种预制挑檐的构造 ,在施工过程中应根据现场环境合理选用     

安钢3#高炉优化操作的生产实践

为稳定高炉炉况，改善高炉操作指标，安钢3^#高炉进行了优化操作实践，取得了较好的效果。