Plasma copolymer membranes of acrylic acid and the adsorption of lysozyme on the surface

Plasma copolymerization was carried out from the monomer mixtures of acrylic acid with hexamethylxdisilozane and hexametydisillazane, and the membranes composed of the Si-C and/or Si-O networks sustaining carboxylic acid group were fabricated. The carboxylic acid contents were dependent on the discharge power conditions as well as the monomer ratio, and carboxylic acid was introduced at the more density in the polymerization by plasmas under the moderate power conditions. The plasma polymer coatings were effective for the adsorption of lysozyme especially on the plasma copolymer films of acrylic acid.     

An information-theoretic methodology for the resolution of pure component spectra without prior information using spectroscopic measurements

The resolution of pure component spectra based on spectroscopic measurements from a reaction system is a challenging task for chemometric systems in the absence of a priori knowledge about the reaction components involved. A popular approach in the literature is based on constrained entropy minimization of the second-order derivative of the resolved pure component spectra. Using an analytical information theoretic framework, it can however be shown that minimization of this cost function is not sufficient to completely separate the underlying components from a set of mixture spectra. Instead, an augmented objective function derived from this analysis is proposed for complete minimization of the mutual information between separated components. The final optimization approach is further shown to be analog to independent component analysis (ICA), a signal processing technique successfully applied to biomedical and speech data to separate linear source mixtures in the absence of a priori information. The developed theoretical insights and proposed methodologies in this paper are illustrated in a simulation study on the separation of three component spectra based on absorbance data acquired from a first-order kinetic reaction system.     

Influence of the common varistor dopants (CoO, Cr2O3 and Nb2O5) on the structural properties of SnO2 ceramics

The influence of dopants commonly used in SnO₂ varistor ceramics, such as CoO, Cr₂O₃ or Nb₂O₅, on the structural properties of SnO₂ was investigated. Several SnO₂-based ceramics containing only one of the dopants were prepared and characterized. Spectroscopic investigations [visible, near infrared (IR) and IR region] were performed to obtain information about dopants valence states inside the ceramics, as well as about their influence on electronic structure of the material. Structural properties were investigated by X-ray diffraction analysis and mechanisms of dopant incorporation were proposed. Obtained results were confirmed with results of the electrical measurements. Microstructural changes in doped ceramics were investigated by scanning electron microscopy (SEM) analysis that showed great differences in densities, grain size, and morphology of the SnO₂ ceramics depending on type of dopants and their distribution.     

电气设备红外诊断的相对温差判断法及判断标准

文章说明了为判断电气设备缺陷而使用相对温差判断方法的必要性,论证了设备对应点的相对温差与其接触电阻的相对偏差的相关关系,确定了相对温差判据的标准,并与现有经验判断实例进行了对比,证实了该文提出了判断的实用性。     

Influence of film thickness on the texture, morphology and electro-optical properties of indium tin oxide films

In the present study, the structural, electrical, and optical properties of indium tin oxide (ITO) films are reported as a function of film thickness (162-840 nm). The properties are discussed in terms of the (100) preferred orientation evolution with the increase of film thickness. This preferred orientation allowed accommodation of more oxygen vacancies, resulting in the increase of carrier concentration from 2.43 × 10²⁰ cm⁻³ to 7.11 × 10²⁰ cm⁻³ and therefore enhancing the electrical conductivity. The absorption in the infrared region was also found to increase with the increasing free carrier concentration, which was attributed to the plasma excitation. The X-ray photoelectron spectroscopy depth profile showed that the Sn⁴⁺ concentration did not change with film thickness. However, the oxygen concentration was decreased slightly after the thickness of the ITO films was increased to 100 nm, as the consequence of the formation of the (100) texture allowing the accommodation of more oxygen vacancies. The results show that the fabrication process can be manipulated to control the electrical properties and the infrared absorption of the sputtered ITO films.     

红外焦平面失效元处理方法及软硬件实现

失效元对红外焦平面阵列器件成像质量的影响较大。本文在给出失效元定义的基础上,对失效元的产生机理进行了分析,并给出了具体的失效元检测方法。基于DSP实现了红外图像的硬件处理系统并编写了失效元处理的软件程序,实现了失效元的自动检测和校正。实验结果表明,所设计的软硬件符合实时性、可靠性的要求,取得了较好的处理效果。     

大视场激光探测与告警技术

利用四路红外非制冷焦平面探测器、大视场光学系统、窄带滤光片和信号处理系统,构成了凝视成像激光探测与告警系统。光学系统采用三片式结构的广角镜头来实现大视场;使用先进的非球面光学设计技术,并以FPGA完成探测器响应信号的非均匀校正,以改善像质;通过光学系统的畸变校正,提高激光的探测方向精度;利用激光和背景强度之间的反差,通过激光目标检测算法进行告警。实验表明,该系统能在127视场范围内对波长为1.315靘, 2.7靘, 3.8靘, 10.6靘的4种激光进行告警,探测功率密度范围为0.05 ~50mW/cm2,探测方向精度可达1。     

Development of Spectral Selective Multilayer Film for a Variable Emittance Device and Its Radiation Properties Measurements

A smart radiation device (SRD) that is a variable emittance radiator has been developed as a thermal control material for spacecraft. The SRD has the unique feature of large variation of the total hemispherical emittance _H near room temperature. The _H of the SRD changes depending on its temperature. However, there is a drawback of a large solar absorptance _S. It is too large to use as a thermal control material for spacecraft. In order to reduce the large _S, spectral selective multilayer film was developed. This multilayer film reflects solar radiation and transmits far-infrared radiation to maintain the variation in the _H of the SRD. This paper presents thermal radiative properties of the SRD with spectral selective multilayer film. The multilayer film was designed by using a genetic algorithm (GA). The designed multilayer film was evaporated on the surface of the SRD by the electron beam evaporation method. The experimental results of _S and _H of the SRD with the multilayer film agreed well with calculated results.     

Spatial spectral evolution in pulsed laser deposited lead-germanate thin films by micro-infrared spectroscopy

Lead-germanate thin films were developed on silicon substrates by pulsed laser deposition from bulk glassy targets of composition 0.4PbO-0.6GeO₂, and micro-infrared transmittance measurements were performed to assess the state of the grown films. Measurements across the radius of films revealed surprisingly large spectral changes, reminiscent of lead-oxide variations in corresponding bulk glasses. To search for the origin of this effect, the infrared spectra were simulated by employing the rigorous expression for the transmittance of a bilayer system to take into full account multiple internal reflections in both thin film and substrate. The results showed that the profiles of the experimental spectra can be accurately described by using as input the complex refractive index of the target glassy material and by considering film thickness variations from the center to the edges of the film. This work demonstrates the strong influence of optical effects on the infrared spectra of thin films, and manifests also the effectiveness of infrared spectroscopy when coupled with rigorous calculations to characterize the structure of thin films.     

MCT列阵光电性能参数自动测试系统

本文介绍了霍尼威尔公司电光分部研制的MCT光电导列阵自动测试系统和洛克希德公司Palo Alto研究实验室研制的焦平面列阵光电参数的自动测试站。检测的光电性能参数包括光电响应率,响应光谱,噪声,探测器的RA乘积,响应频谱,光学串音和电学串音,响应率的空间频谱,调制传递函数等。