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回顾了中子单粒子研究的国内外发展情况,介绍了近几年西北核技术研究所在西安脉冲堆开展的低能中子单粒子效应研究进展。比较了稳态与脉冲工况下中子单粒子效应的异同性;分析了含有SRAM结构器件随着特征尺寸的减小,中子单粒子效应敏感性加剧的物理机制。分析认为目前中子单粒子效应已成为小尺寸大规模互补金属氧化物半导体器件的主要中子效应表现;中子辐射效应研究中,除了位移损伤效应以外还必需重视由中子电离造成的中子单粒子效应。 相似文献
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Realizing variable contrast technique in MRC measuring target using integrating sphere 总被引:2,自引:0,他引:2
In order to realize variable contrast in the minimum resolvable contrast (MRC) measuring target in the visible imaging system, a novel technique is presented, which adopts two integrating spheres to illuminate two sides of target respectively and the different contrasts can be achieved by regulating the luminance in two integrating spheres. This technique can make the contrast be regulated more conveniently. Based on this technique, the MRC measuring device is developed. This device can be used in all kinds of trial fields. The expanded uncertainty of measuring MRC is less than 3%. 相似文献
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A set of system based on personal computer for the bi-directional reflectance distribution function (BRDF) measurement was developed, whose laser wavelengths cover 0.6328, 1.34, 3.39, and 10.6 μm from visible to infrared. Stray light in BRDF measurement system was analyzed. It can be reduced and suppressed by the design of the system light path in BRDF measurement system, the choice of the measuring scheme, the processing to the optoelectronic signal, and the radiation control of the optical components and mechanical equipments. So the minimum measurable value of BRDF is less than 10-5/sr. 相似文献
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使用激光共聚焦拉曼光谱仪测量正常大鼠红细胞、正常人红细胞、糖尿病STZ造模大鼠红细胞、糖尿病四氧嘧啶造模大鼠红细胞和人Ⅱ型糖尿病红细胞的拉曼光谱,应用主成分分析(principal component analysis,PCA)结合支持向量机(support vector machines,SVM)分类器对数据进行判别分析,然后采用类间距离判断两种造模方法与人Ⅱ型糖尿病的接近程度。结果发现糖尿病红细胞与正常红细胞的拉曼光谱存在明显差异,糖尿病在酰胺 ⅥCO变形振动谱带处峰高显著,并在酰胺ⅤN—H变形振动谱带处谱线出现偏移,属于磷脂的脂酰基C—C骨架1 130 cm-1谱线增强,1 088 cm-1谱线强度减弱,说明糖尿病红细胞膜的通透性增强。PCA结合SVM可以很好地区分以上5类红细胞的拉曼光谱,分类器测试结果表明分类准确度达100%。通过分别计算两种造模方法与人Ⅱ型糖尿病的类间距离,发现STZ造模法更接近人Ⅱ型糖尿病。由此得出结论:拉曼光谱法可以用于糖尿病诊断,大鼠糖尿病STZ造模法更接近人类Ⅱ型糖尿病。 相似文献
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糖尿病是严重威胁人类健康的慢性疾病之一,对其进行早期诊断尤为重要。由于糖尿病病程的发展会对血液中红细胞的结构和功能产生影响,因此利用红细胞荧光光谱在特征峰位和峰高等方面的差异性,可以对糖尿病状态进行诊断。在选取光谱信号的差异性作为特征向量方面,可以采用荧光光谱信号的非线性程度作为特征向量。为更好地描述荧光光谱信号的非线性,采用延迟向量方差(DVV)法描述信号的非线性程度。采用迭代幅度匹配傅里叶变换(IAAFT)法产生原始数据的替代数据,通过比较原始数据与替代数据的延迟向量方差确定原始数据的非线性特征。以原始数据目标方差为横坐标,以其替代数据目标方差为纵坐标,画出延迟向量方差散布图。健康大鼠红细胞荧光光谱的延迟向量方差散布图与其对角线几乎重合,说明健康大鼠红细胞荧光光谱非线性程度较低;而糖尿病大鼠红细胞荧光光谱的延迟向量方差散布图偏离其对角线,说明糖尿病大鼠红细胞荧光光谱非线性程度较高,并且氨基酸对应的光谱段非线性程度更深。据此,提出健康和糖尿病荧光光谱之间的非线性差异程度可以作为糖尿病早期诊断的特征之一。 相似文献
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When using a single reference to measure the bi-directional scattering distribution function (BSDF), the incident zenith angle of the tested sample must be identical to that of the reference. In order to get the hemisphere space scattering characteristic on the sample surface, usually a motor drives the sample tilting, then the incident zenith angle is changed and needs to be the compensated by another motor. We mathematically deduce the expression of compensation angle when the incident zenith angle is changed by the rotation of motor. After the incident angle is compensated, the scattering zenith angle and azimuth angle are deduced too. The uncertainty of the system is 0.75%. Scattering measurements are performed on copper sample with visible light under different temperatures. 相似文献
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