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101.
介绍便携式温度计校验仪的工作原理及研制过程。对该仪器的恒温槽体机械结构、制冷器和散热器的设计、恒温槽体温度测量及控制等进行了详细叙述。该仪器提供的温度场稳定、均匀,在-20~100℃范围内可任意设定温度。解决了温度计现场快速校准的问题。  相似文献   
102.
The structures and electronic states of phenyl-capped terthiophene (denoted by P3T) and the ionic species of P3T have been investigated by means of density functional theory (DFT) and direct MO dynamics calculations. P3T is one of the high-performance molecular devices, which has been utilized as a semi-conductor. The calculations indicated that the neutral P3T has a non-planar structure whose the phenyl rings in both ends of thiophene chain are largely deviated from the molecular plane. The cation and anion radicals, dication and dianion were considered as its ionic states. The structure for cation radical of P3T is close to more planar than that of neutral P3T. The structures for anion radical, dication and dianion take a pure planar structure. The first excitation energy of neutral P3T is calculated to be 2.90 eV at the TD-B3LYP/6-31G(d)//B3LYP/6-311+G(d) level, while the P3T cation and anion radicals have lower excitation energies (1.22 and 1.10 eV, respectively). The direct MO dynamics calculation showed that neutral, cation and anion hold near planar structure at 300 K. On the other hand, oligothiophene (n = 5) and its ionic species are strongly deformed from the planar structure, and thiophene rings in both ends of chain rotate rapidly by thermal activation. The mechanism of the electron conductivity in P3T was discussed on the basis of theoretical results.  相似文献   
103.
Optimum compositions of ion-selective membranes in quasi-binary systems CuCl-CdCl2, LiCl-CdCl2, and In2S3-InCl3 are selected by a method of coulometric titration in cells with solid electrolytes. Transport numbers for ions are close to unity for the optimum compositions; transport numbers for electrons are vanishingly small ( ≺10−3 to 10−4); the electroconductivity is equal to ≈ 10−3 S cm−1 at 200°C; the diffusion coefficients for the current-producing component are on the order of 10−6 to 10−7 cm2 s−1. When using a solid electrolyte of the composition CuCl-CdCl2, which contains 30 mol % CdCl2, methods of emf and electroconduction reveal that the region of homogeneity of copper(I) selenide falls in the region of compositions Cu1.33Se-Cu2.67Se.__________Translated from Elektrokhimiya, Vol. 41, No. 6, 2005, pp. 721–727.Original Russian Text Copyright © 2005 by Leushina, Kolesnikova, Makhanova, Zlomanov.Published on the basis of a report delivered at the VII Meeting on Fundamental Problems in Solid-State Ionics (Chernogolovka-2004).  相似文献   
104.
环状芴基张力半导体由于其特殊的分子结构,发射状排布的p轨道和纳米级空腔等诸多特点,引起了科学家广泛的关注.相对于直链型芴基半导体,环状芴基张力半导体展现出独特的光电性质.然而,迄今为止其振动性质没有被报道.对四元环芴的晶体与直链四聚芴粉末样品进行拉曼光谱表征和归一化处理,并结合理论计算.结果表明,与直链寡聚芴相比,环芴类似于碳纳米管的G峰发生了偏移,并且低频区域拉曼频移峰的峰强增加.其原因是由于张力的引入,改变了芴基主链的骨架和电子结构,加强芴骨架上π电子离域,同时使环芴中每个芴单元都参与到振动中.该研究结果为芴基张力半导体材料拉曼光谱的研究提供了一定的工作基础.  相似文献   
105.
    
This paper describes experimental results obtained with a packaged GaAs Schottky barrier diode in contact with a coaxial connector and placed across waveguides for bands Ka, V, E, W or F. Among the microwave sources used for calibration were 9 carcinotrons in the frequency interval 51–490 GHz. As soon as the frequency F is above the waveguide cut-off frequency, the different characteristics do not depend critically on the waveguide size for V, E, W and F bands. The video detection sensitivity, of several 100 mV/mW at 50 GHz and below, decreases as F–4 in the range 51–500 GHz. Coupling an X-band centimeter frequency via the coaxial connector and a millimeter frequency via the waveguide permits harmonic mixing in the diode. Between 36 and 490 GHz, the harmonic mixing number varies from 3 up to the very large value 40 with conversion losses from 18 to 88 dB. The minimum detectable signal in the 100 kHz band can be as low as –90 dBm at 80 GHz. A noticeable millimeter power is available at the waveguide output from injected centimeter power by harmonic generation. Starting for instance with 100 mW around 11.5 GHz, we have measured 0.1 mW at 80 GHz and 0.1 W at 230 GHz. To illustrate the possibility of creating usable millimeter and submillimeter wave without heavy equipment (such as carcinotrons or millimeter klystron) we report spectroscopic experiments in Rydberg atoms. Resonances have been observed up to 340 GHz by harmonic generation (28th harmonic) from an X-band klystron).  相似文献   
106.
Nano-structured WO3-TiO2 layers were prepared by the sol-gel route. To obtain transparent, porous and crack free layers up to 0.8 μ m with a single dipping cycle a templating strategy was used. As a template three-dimensionally network based on organically modified silane was introduced to the WO3 and TiO2 sols. The WO3 layers were dip-coated onto the conductive glass substrate (TCO) and the TiO2 layers on the top of the WO3 layer. The morphology and the structure of the layers were determined by Scanning Electron Microscopy (SEM), High Resolution Transmission Electron Microscopy (HR-TEM), Energy Dispersive X-Ray Spectroscopy (EDXS), Auger and Infrared spectroscopy. SEM image of the WO3-TiO2 layer confirmed the nano-porosity of the layers and give the size of the particles of about 10 nm for TiO2 and 30 nm for WO3 layer. Further analysis indicated that the titanium sol penetrates the WO3 layer. Particles in the WO3 layer consist of a crystalline monoclinic WO3 core surrounded by a 5–10 nm amorphous phase consisting of WO3, TiO2 and SiO2. The WO3-TiO2 layers were used to assemble all solid state photoelectrochromic (PE) devices. Under 1 sun irradiation (1000 W/m2) the visible transmittance of the PE device changes from 62% to 1.6%. The colouring and bleaching processes last about 10 minutes.  相似文献   
107.
 利用变截面波导的耦合模理论,根据输出腔中电场幅值分布函数所满足的微分方程组,编写了具有自动优化功能的计算程序,分析研究了不同渐变角度、考虑腔体损耗前后和输出腔与外电路失配时,谐振频率、腔体品质因数和高频场幅值沿轴分布的变化情况,为进一步研究高频场与电子注的互作用和输出腔奠定了基础。  相似文献   
108.
量子点在生物化学分析中的应用   总被引:1,自引:0,他引:1  
钟萍 《广州化学》2008,33(2):80-86
量子点(quantumdots,QDs)由于其优异的光学和电学特性,作为新型的荧光试剂探针对生物大分子进行标记,成为近年来迅速发展的纳米材料在生化分析领域的重要应用之一。文章简述了量子点的基本特性,对制备和修饰量子点的各种方法进行比较总结,重点阐述量子点在生物化学分析中的新进展,尤其是对生物大分子的识别和标记作了详细的总结,并提出研究中存在的一些待解决的问题以及今后量子点的研究方向。  相似文献   
109.
对二维NAS-RIF算法进行了改进,并将它用于三维显微图像复原,分别用模拟样本和真实生物样本进行了实验。针对原算法对噪声有放大作用,提出了基于中值滤波去噪的改进。在支持域的确定、最小点的搜索上进行改进,提高复原质量。改进了原算法仅适用于均匀背景的不足,扩大了应用范围。实验结果表明,该算法在三维显微图像盲复原中具有较好的效果。  相似文献   
110.
刘兴法  马佳光  岑明 《光子学报》2008,37(10):2067-2071
针对三轴光电跟踪系统在地平式盲区内的跟踪策略所具有的多样性,对天顶附近三轴光电跟踪系统Z轴运动状态进行了分析.仿真结果表明:地平式盲区内Z轴做匀角速运动有利于  相似文献   
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