337 resultados para G00-1417


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设计了一种新型的与MS/RF CMOS工艺全兼容、带深n阱(DNW)、浅沟槽隔离(STI)的双光电探测器,分析了其工作机理,用器件模拟软件ATLAS对其暗电流、响应电流、光调制频率响应和波长响应进行了模拟.采用TSMC 0.18 μm MS/RF CMOS工艺进行了流片,对芯片进行了暗电流和响应度的测试.模拟和测试结果均表明,该探测器与常规双光电探测器相比,具有较低的暗电流和较高的响应度.

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本文提出了一种模式识别理论的新模型,它是基于“认识”事物而不是基于“区分”事物为目的。与传统以“最佳划分”为目标的统计模式识别相比,它更接近于人类“认识”事物的特性,故称为“仿生模式识别”。它的数学方法在于研究特征空间中样本集合的拓扑性质,故亦称作“拓扑模式识别”。“拓扑模式识别”的理论基点在于它确认了特征空间中同类样本的连续性(不能分裂成两个彼此不邻接的部分)特性。文中用“仿生模式识别”理论及其“高维空间复杂几何形体覆盖神经网络”识别方法,对地平面刚体目标全方位识别问题作了实验。对各种形状相像的动物及车辆模型作全方位8800次识别,结果正确识别率为99.75%,错误识别率与拒识率分别为0与0.25%。

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自然景观真实感的模拟是计算机图形学领域中的研究热点和难点之一.尽管人们对静态云的真实感模拟进行了大量的研究,动态云模拟的工作还比较少.动态云的快速模拟技术在计算机游戏动画、飞行视景仿真、影视广告等许多领域具有重要的应用价值.提出了一种三维动态云快速模拟的新方法.首先,在较低分辨率的网格上求解云运动的物理方程,获得动态云的速度场.然后,采用纹理漂移的方法来增加云的表面细节.通过充分利用GPU的加速性能,该算法可以达到较高的绘制速度.最后,对上述算法进一步优化处理,使其可以适用于多种硬件平台.

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The heat capacities of p-chlorobenzoic acid were measured in the temperature range from 80 to 580 K by means of an automatic adiabatic calorimeter equipped with a small sample cell of internal volume of 7.4cm(3). The construction and procedures of the calorimetric system were described in detail. The performance of this calorimetric apparatus was evaluated by heat capacity measurements on alpha-Al2O3. The deviations of experimental heat capacities from the corresponding smoothed values lie within +/-0.28 per cent, while the inaccuracy is within +/-0.40 per cent, compared with the recommended reference data in the whole experimental temperature range. A fusion transition at T = 512.280 K was found from the C-p-T curve of p-chlorobenzoic acid. The enthalpy and entropy of the phase transition, as well as the thermodynamic functions {G((T)) - G((298.15))}, {H-(T) - H-(298.15)} and {S-(T) - S-298.15}, were derived from the heat capacity data. The mass fraction purity of p-chlorobenzoic acid sample used in the present calorimetric study was determined to be 0.99935 by fraction melting approach. (C) 2002 Elsevier Science Ltd. All rights reserved.

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利用rep-PCR指纹技术对云南5个地区的尼泊尔桤木根瘤内Frankia菌基因多样性进行研究,实验发现Frankia菌呈现丰富的基因多样性.所有71个样品被分为11种不同的基因类型.除高黎贡山外,不同地域都有某种基因型占优势,显示Frankia菌基因型与地域有紧密关系.所观察的5个地区中,高黎贡山Frankia菌基因型种类最多,多样性指数最高,基因多样性最为丰富.结合高黎贡山地理资料及其它生物多样性相关研究,推测与高黎贡山尼泊尔桤木共生的Frankia可能作为种储备库,为其它地区的寄主植物提供了祖先菌株.图8表1参13

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水文尺度问题是当今水文学研究的热点和前沿.水文尺度包括过程尺度、观测尺度和模拟尺度三方面含义.主导过程尺度作为尺度的特征量,是水文研究中的重点.水文尺度转换工作包括了对水文模式、参数、状态变量和输入的尺度转换四方面,每一方面都有其特殊的研究方法.水文系统的有组织复杂性、时空变异性和数据不足是当前水文研究的难点所在.自然河网的自相似特性使其成为水文尺度研究的重要组成部分.进一步深入研究水文尺度问题需要多种研究思路、技术手段和理论工具的结合.

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A novel hybrid photochromic composite film composed of Preyssler's heteropoly acid H-12[EuP5W30O110] (EuP5W30) and polyvinylpyrrolidone (PVP) was prepared by dip-coating method. Atomic force microscopy (AFM) was used to investigate the surface topography. The change of characteristic peak in the infrared spectra (IR) was investigated. The TG curve showed three steps of weight loss and approximately revealed the composition of the hybrid film. Ultraviolet-visible adsorption spectra (UV-VIS) and electron resonance spectrum (ESR) were used to investigate the photochromic behavior and mechanism of hybrid film. The photoluminescent behavior of the film at room temperature was investigated to show the characteristic Eu3+ emission pattern of D-5(o)-F-7(J). The occurrence of photoluminescent activity confirms the potential for creating luminescent thin film with polyoxometalates (POMs).

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Possible changes in the structure and properties of maleated polyethylene (HDPE-MA) at different degrees of grafting (D.G.) were examined. At the level of 1.6 maleic anhydride (MA)/100 ethylene units E, 70-80% of crystallinity of the parent PE was retaine