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用溶胶-凝胶法在非晶玻璃上制备VO2薄膜,经过熔融、涂膜、烘干和热处理等工艺最后得到电阻相变2~3个量级的VO2薄膜.对烘干温度、熔融温度、膜厚和热处理温度对薄膜电阻开关特性的影响进行了研究.通过AFM,XRD和XPS对薄膜的结构和特性进行分析. 相似文献
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采用射频磁控溅射方法和热处理工艺制备了二氧化钒(VO2)薄膜,并制作了金属钨/VO2/金属钨三明治结构,通过改变金属钨/VO2/金属钨三明治结构中VO2薄膜与金属钨电极的接触面积,研究了VO2薄膜的电致相变特性.采用x射线衍射仪(XRD)、扫描电子显微镜(SEM)、四探针和半导体参数测试仪对VO2薄膜的结晶取向、表面形貌、方块电阻和,I-V特性进行了测试.实验结果表明,所制备的VO2薄膜为具有热致相变特性的单一组分VO2纳米薄膜,在热激励下,薄膜的方块电阻相变幅度达到2个数量级;在电压的激励下,VO2薄膜与金属钨的接触面积为12μm×12um时,电流发生跳变的阁值电压为9.4V,随着接触面积的减小,闽值电压也逐渐降低. 相似文献
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原子层沉积(ALD)技术在制备薄膜时因具有厚度精确可控、三维均匀性好以及可以实现大面积成膜和低的成膜温度等优点而使其在各个领域受到广泛关注。本文采用ALD技术,以VO(acac)2和O2分别为钒源和氧源,使用不同的沉积温度(420~480℃)和退火条件(自然冷却、4和8h程序降温)在玻璃基底表面制备VO2薄膜。通过X-射线光电子能谱、X-射线衍射以及扫描电镜对薄膜的价态、结晶状况及表面微观形貌进行表征;通过四探针测试仪对所制备薄膜的半导体-金属相变特性进行了研究。实验结果表明:VO2薄膜相变特性与其微观结构和晶体取向有着直接关系。选择ALD脉冲时序为[10s-20s-20s-20s],循环周期数为300,在450℃沉积且采取自然冷却所制备的VO2薄膜结晶状态良好,相变前后薄膜方块电阻突变量大,具有良好的热致相变特性。因此,该ALD技术可以制备相变特性较好的VO2薄膜。 相似文献
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VO2薄膜及电学开关特性 总被引:2,自引:0,他引:2
用溶胶-凝胶法在非晶玻璃上制备VO2薄膜,经过熔融、涂膜、烘干和热处理等工艺最后得到电阻相变2-3个量级的VO2薄膜。对烘干温度、熔融温度、膜厚和热处理温度对薄膜电阻开关特性的影响进行了研究。通过AFM,XRD和XPS对薄膜的结构和特性进行分析。 相似文献
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直流反应磁控溅射法制备VO_2薄膜 总被引:1,自引:0,他引:1
VO2是一种相变材料.发生相变时,VO2的电阻、透过率、反射率都会发生显著的变化;反应磁控溅射法是制备VO2薄膜的一种比较理想的方法.文中,重点讨论氧氩气质量流量比m(O2)/m(Ar)、基片温度以及沉积后薄膜的退火处理对制备薄膜成分、结构和性能的影响.通过分析得出m(O2)/m(Ar)比在113和112间具有较高的VO2含量;基片温度在250℃时具有较佳的VO2结晶特性;450 ℃保持2 h的真空退火处理可以改变薄膜成分和结构,使高价的V2O5薄膜还原到四价的VO2,且明显减少薄膜的氧缺陷,提高氧原子的含量,减少空洞,增加晶粒尺寸提高膜的致密度. 相似文献
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A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling. 相似文献
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Liebert A Wabnitz H Grosenick D Möller M Macdonald R Rinneberg H 《Applied optics》2003,42(28):5785-5792
A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue. 相似文献
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An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a
rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate
agreement is demonstrated between the derived relations and experimental data. 相似文献
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Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995. 相似文献
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由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。 相似文献
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M. M. Gadenin 《Inorganic Materials》2013,49(15):1352-1356
It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle. 相似文献
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V. T. Kornienko 《Strength of Materials》1991,23(7):760-765
The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991. 相似文献
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水三相点是开尔文热力学温度的唯一基准点,也是ITS-90国际温标重要的定义固定点。因此,水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来,中国计量科学研究院研制出一系列高质量的水三相点容器,加强了水三相点的研究,为不确定度的分析提供了更为可靠的实验依据。同时,不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此,根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明,其扩展不确定度为0.16mK(k=2.69,P=0.99)。 相似文献