Influence of aircraft surface distribution on electromagnetic scattering characteristics

In this paper, two typical stealth aircraft concepts (wing fuselage blended and flying-wing) were designed. Then three gradually changed surface distribution models with the same plan-form for each concept were created. Based on the multilevel fast multipole algorithm (MLFMA), the vertical polarization transmitting/vertical polarization receiving (VV) and horizontal polariza-tion transmitting/horizontal polarization receiving (HH) radar cross section (RCS) characteristics were simulated with five frequencies between 0.1 and 1.0 GHz. The influences and mechanisms of aircraft surface distribution on electromagnetic scattering characteristics were investigated. The results show that for the wing fuselage blended concept, the VV RCS of this frequency range is higher than the HH RCS in most cases, while it is just the opposite for the flying-wing concept. As for the two aircraft concepts, the RCS levels of HH and VV both decrease with the frequency increasing, but the HH RCS has a faster downward trend. The surface distribution has little influ-ence on HH RCS characteristics. On the contrary, it has a significant impact on VV RCS charac-teristics, and the amplitude of the VV RCS increases with the surface thickness.     

一种高温合金粉末预处理后表面的分析

本文用ESCA及电子显微分析方法研究了预处理Rene’95粉末表面的成分及析出相情况。预处理后粉末表面出现大量ZrO_2析出。雾化粉末表面的M’C碳化物在原位转变成MC。在粉末表面上还有大量二次碳化物,这些碳化物依附表面氧化物生核长大。预处理不能减少表面析出相数量,也未改变表面析出相的类型。     

分形表面的结构函数及其应用

介绍了用于表征分形表面的结构函数的定义，起因以及与其它统计量的关系，并给出了实验和结果分析。     

新型声表面波气体传感器

介绍了声表面波（SAW）气体传感器的工作原理及器件制作，提出了1种表面波SO2传感器，它采用三乙醇胺（TEA）覆盖薄膜，分辨率可达70×10－9。还讨论了SAW气体传感器的稳定性、可靠性、灵敏度及选择性等问题，并给出了有关的实验结果。     

辐射发射与辐射法测温—如何接近表面真实温度

从辐射测法中辐射率变化对温度的影响，讨论了多色辐射测量法的发展与应用实践，比较了不同处理方法的优缺点。     

The Mercury Atmospheric and Surface Composition Spectrometer for the MESSENGER Mission

The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) is one of seven science instruments onboard the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft en route to the planet Mercury. MASCS consists of a small Cassegrain telescope with 257-mm effective focal length and a 50-mm aperture that simultaneously feeds an UltraViolet and Visible Spectrometer (UVVS) and a Visible and InfraRed Spectrograph (VIRS). UVVS is a 125-mm focal length, scanning grating, Ebert-Fastie monochromator equipped with three photomultiplier tube detectors that cover far ultraviolet (115–180 nm), middle ultraviolet (160–320 nm), and visible (250–600 nm) wavelengths with an average 0.6-nm spectral resolution. It will measure altitude profiles of known species in order to determine the composition and structure of Mercury’s exosphere and its variability and will search for previously undetected exospheric species. VIRS is a 210-mm focal length, fixed concave grating spectrograph equipped with a beam splitter that simultaneously disperses the spectrum onto a 512-element silicon visible photodiode array (300–1050 nm) and a 256-element indium-gallium-arsenide infrared photodiode array 850–1,450 nm. It will obtain maps of surface reflectance spectra with a 5-nm resolution in the 300–1,450 nm wavelength range that will be used to investigate mineralogical composition on spatial scales of 5 km. UVVS will also observe the surface in the far and middle ultraviolet at a 10-km or smaller spatial scale. This paper summarizes the science rationale and measurement objectives for MASCS, discusses its detailed design and its calibration requirements, and briefly outlines observation strategies for its use during MESSENGER orbital operations around Mercury.     

用于表面温度测量的导热反问题的误差研究

讨论了用于温度测量的非稳态一维线性导热反问题。通过引入正则参数 ,这种不适定问题得到了稳定的解。在给出非级数形式的分析解后 ,计算误差可以通过数值解与准确解的比较确定。同时讨论了影响计算误差的各种因素。     

三维表面形貌的功能评定方法

三维表面形貌受生成机理的影响 ,与表面功能密切相关 ,对表面的功能评定至关重要。论述了三维表面功能评定的各种方法 ,如最小二乘多项式拟合、滤波、Motif法和分形方法 ,并分析归纳了存在的问题和发展趋势。     

金属基体表面活性保护与金属镀层结合力的研究

通过几种特性物质在钢铁电极表面吸脱附电位和微分电容曲线及含有这些特性物质的镀铅电解液阴极化曲线的测试,发现电沉积时铜的初始析出电位值,在特性物质吸脱附电位区间和金属基本表现酸蚀活化后的活性保护,是取得具有牢固结合力镀层的必要条件。     

N—取代烯丙基芳纶的表面特性

用现代仪器分析技术了Ｎ－取代烯丙基芳纶表面的表态、化学结构、结晶性、热稳定性及热裂解动力学等表面特性。