数控慢走丝线切割机床锥度切割的方法

模具行业的迅速发展推动了电火花线切割技术的进步，数控慢走丝线切割机床以其自动化程度高、精度好、加工稳定、可靠的优点开辟了广阔的市场前景。本文主要介绍了FUNAC线切割机床锥度切割的方法，重点介绍了当锥度有误差时，应如何进行补偿。     

CHIP FORMATION MODEL OF TITANIUM ALLOYS

钛合金的切屑变形从低速起就是一种典型的集中剪切滑移，这种集中剪切滑移在高速切削大部分难加工材料时是一种普遍现象。本文研究了钛合金加工的切屑形成过程并提出了描述集中剪切切屑形成过程的三阶段模型。该模型解释了集中剪切切屑节块如何启动、梯形化并最终形成锯齿形切屑。     

多型腔零件加工区域的自动识别和刀轨生成

从工程实际应用出发，提出并解决了二维平面多型胺零件的型腔区域的自组织别问题：即仅依靠型腔轮廓环和岛屿轮廓环的几何信息，不需要知道哪 个轮廓环是型腔轮廓环，哪 个轮廓环是岛屿轮廓环，也不需要知道哪 几个轮廓环合在一起构成一个型腔。     

基于CFD的发动机舱流场及温度场数值仿真

以内埋式通风口为研究对象，应用？昆合化网格，建立发动机短舱模型。采用SIMPLE算法，求解了流动和换热控制方程。对舱内流动和换热问题进行研究，得到了地面开车、地面滑行，以及不同高度、不同马赫数条件下动力装置舱内流场和温度场，解决了内埋式通风口进口流量无法测量的难题，为新型动力装置冷却通风系统的研究具有指导意义。     

航空发动机防喘系统扩稳构件优化研究

为获得防喘系统的最佳效能，采用温度畸变发生器作为逼喘装置，分别给出了不同发动机扩稳构件的试验结果。优化试验以发动机进口临界温升为目标。讨论了某涡扇、涡喷发动机扩稳构件在不同形式组合方案下的扩稳效果。结果表明．防喘系统扩稳效果最为显著的是采用减少或切断燃油的手段，但其缺点是会导致推力下降较大，因此扩稳方案需综合考虑，应从有效性、发动机重量、机动飞行和可靠性能力等方面进行权衡。     

六点炉温追踪仪在涂装线上的应用

六点炉温追踪仪（ＢＹＫＯ－ＴＲＡＣＫ）能准确、科学的测试各种不同结构烘房的温度曲线。本文介绍了该仪器在烘房的工艺设计、工件烘烤质量及涂料选材等方面的应用。     

Electron temperature anisotropy effects on tearing mode in ion-scale current sheets

Recent two-dimensional (2-D) particle-in-cell (PIC) simulations have shown that there is a critical thickness of a current sheet, above which no significant saturation amplitude of the 2-D tearing (TI) mode can be expected. Here, we have introduced the initial electron temperature anisotropy (α_e0 = T_e⊥/T_e|| > 1), which is known to raise significantly the linear growth rates, and inspected if α_e0 > 1 can change the saturation level of the TI in a super-critical current sheet. Varying α_e0 and D (D: the current sheet half-thickness) systematically, we have found that while α_e0 boosts up the linear growth rate in both sub- and super-critical current sheets, macroscopic effects are obtained only in sub-critical current sheets, that is, energy transfer from the fastest growing short wavelength modes to longer wavelength modes are available only in the sub-critical regime. Since the critical thickness is a fraction of the ion inertial length, the tearing mode assisted by the electron temperature anisotropy alone, despite its significant boost in the linear growth rate, cannot be the agent for reconnection triggering in a current sheet of ion-scale thickness.     

Tool Life and Surface Integrity in High-speed Milling of Titanium Alloy TA15 with PCD/PCBN Tools

Titanium alloys are widely used in aeronautics that demand a good combination of high strength, good corrosion resistance and low mass. The mechanical properties lead to challenges in machining operations such as high process temperature as well as rapidly increasing tool wear. The conventional tool materials are not able to maintain their hardness and other mechanical properties at higher cutting temperatures encountered in high speed machining. In this work, the new material tools, which are polycrystalline diamond (PCD) and polycrystalline cubic boron nitride (PCBN) tools, are used in high-speed milling of Ti-6.5Al-2Zr-1Mo-1V (TA15) alloy. The performance and wear mechanism of the tools are investigated. Compared to PCBN tool, PCD tool has a much longer tool life, especially at higher cutting speeds. Analyses based on the SEM and EDX suggest that attrition, adhesion and diffusion are the main wear mechanisms of PCD and PCBN tools in high-speed milling of TA15. Oxidation wear is also observed at PCBN tool/workpiece interface. Roughness, defects, micro-hardness and microstructure of the machined surface are investigated. The recorded surface roughness values with PCD/PCBN tools are bellow 0.3 μm at initial and steady cutting stage. Micro-hardness analysis shows that the machined surface hardening depth with PCD and PCBN tools is small. There is no evidence of sub-surface defects with PCD and PCBN tools. It is concluded that for TA15 alloy, high-speed milling can be carried out with PCD/PCBN tools.     

Investigations on temperature distribution of satellite surfaces affected by solar absorptivity

Based on the Monte Carlo ray-tracing method, the network coefficients of thermal network model describing the radiation heat transfer among satellite surfaces is solved by considering the surface material optical characters. It is superiority to the conventional Gebhart’s method in view of the grey body and the diffuse reflection assumptions. The zone leveling method is used to discrete the governing equations and the solar absorpivity is separated and considered to be an important correction parameter. Effects of the solar incidence round angle, the zenith angle and the ratio of absorpivity to emissivity (RAE) on temperature distribution are numerically simulated and discussed in detail. The higher or the lower the RAE may be lead to the alternative heating and cooling tend with a larger heating or cooling velocity of main body surfaces than the solar array surfaces. Furthermore, maximum temperature of main body is almost larger than solar arrays. Under the same RAE, solar incidence angle make a great effect on the uniform character of temperature distribution.     

An analysis of the topside ionosphere parameters based on the long-duration Irkutsk incoherent scatter radar measurements

The topside ionosphere parameters are studied based on the long-duration Irkutsk incoherent scatter radar (52.9N, 103.3E) measurements conducted in September 2005, June and December 2007. As a topside ionosphere parameter we chose the vertical scale height (VSH) related to the gradient of the electron density logarithm above the peak height. For morphological studies we used median electron density profiles. Besides the median behavior we also studied VSH disturbances (deviations from median values) during the magnetic storm of September 11th 2005. We compared the Irkutsk incoherent scatter radar data with the Millstone Hill and Arecibo incoherent scatter radar observations, the IRI-2007 prediction (using the two topside options) and VSH derived from the Irkutsk DPS-4 Digisonde bottomside measurements.