共查询到17条相似文献,搜索用时 109 毫秒
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防晒指数SPF(Sun Protection Factor)是防晒用品的主要指标,本文利用紫外分光光度计测量市面常见各种品牌的不同SPF值的100个防晒霜样本在中波紫外线(UVB)的透光率,测量结果表明光谱分析方法可以有效地测量防晒霜SPF值,从而可以鉴别防晒霜上标示的SPF值是否准确. 相似文献
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防晒指数SPF是反映防晒用品防晒效果的主要指标,文章采用ASD公司的便携式光谱仪研究了防晒指数与光谱特性之间的关系。选用丁家宜SPF15,SPF20,SPF30三种品种防晒霜共75个样本进行了光谱分析,将样本分为60个试验样本和15个预测样本,用光谱仪获取样本的反射光谱数据。采用主成分分析法对400~960 nm范围内光谱数据进行处理,表明主成分1和主成分2的累计可信度达91%,再用偏最小二乘回归方法建立了校正模型,并用该模型对剩余15个样本进行预测。结果表明,预测相关系数为0.967 7,得到了较好的预测结果。说明文章提出的光谱分析方法具有很好的分类和鉴别作用,为防晒霜SPF值的检测提供了一种新方法。 相似文献
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利用组合式多功能光栅光谱仪、溴钨灯和吸收池,对遮阳品进行光谱特性分析.对3种样品的基线和透射谱进行了对比,并配合对样品透过率的分析,得到样品的防紫外线性能,从而开发出一个非常受学生欢迎的、将物理实验与实际生活联系起来的实验. 相似文献
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不同酶法对猪皮中提取胶原蛋白的紫外线吸收对比分析 总被引:2,自引:0,他引:2
为获得具有良好紫外线吸收能力的猪皮胶原蛋白水解物,应用于保养品中一种天然的防晒素材,以丰富价廉的猪皮为材料,获取胶原蛋白后,经不同温度预热,凤梨酶、木瓜酶、胃蛋白酶等进行不同时间水解,结果显示,所得的水解液均对短波紫外线吸收能力最佳,其次为中波紫外线,三者中以胃蛋白酶组较佳,以0.5%胶原蛋白经95 C预热30min,再以1%胃蛋白酶水解1h,可获得最佳紫外线吸收能力. 相似文献
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He-Ne激光、紫外线诱变氧化亚铁硫杆菌及耐砷菌株的选育 总被引:6,自引:0,他引:6
对适合氧化亚铁硫杆菌(Thiobacilus ferrooxidans)特点的诱变方法进行了研究:把菌体制成无铁细胞悬液进行小剂量、多次数的诱变.氧化亚铁硫杆菌菌株S1经多次紫外线和激光照射,并结合逐级驯化处理,最终选育出了优良耐砷菌株Sx,它能在含11g/LAs2O3的环境中生长,比出发菌株的0.7g/L提高了近14.7倍.在用该菌株进行浸矿的实验结果表明:浸矿能力良好,在同样是10%接种量时,浸出时间比出发菌缩短了一天,并且砷元素的浸出率由原先的76%提高至85.7%. 相似文献
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为探究利用高分六号卫星宽幅(GF-6 WFV)数据识别火烧迹地的适宜光谱波段和指数,选取2019年发生在我国内蒙古大兴安岭林区的三处雷击火形成的火烧迹地作为研究区,结合GF-6 WFV波段组成,选取归一化植被指数(normalized difference vegetation index,NDVI)、全球环境监测指数... 相似文献
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荧光寿命的正弦调制测量法及分析 总被引:2,自引:0,他引:2
设计并制作了光强调制度和频率可调的发光二极管驱动电路,应用这种激励源激发荧光样品Eu2L′3·nH2O(L′=C4H4O4),测量了激发光和Eu3+离子的5D0—7F2发射光的波形。实验得到的数据用按照相位法测量荧光寿命的原理用非线性最小平方曲线拟合,得到Eu3+离子激发态5D0的寿命约为0.680 ms。讨论了光源调制中的高次谐波分量对测量结果的影响以及寿命具有一定分布的多指数衰减体系的测量和处理方式,提出应用傅里叶级数展开处理数据的修正方法,以扩大相位法测量荧光寿命的适用范围,得到更准确的荧光寿命值。 相似文献
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成都地区太阳紫外辐射光谱的观测与分析 总被引:1,自引:0,他引:1
利用紫外CCD光学多道分析器,对成都地区2006年3月至7月UVA和UVB波段太阳紫外辐射光谱进行了观测,对这一地区紫外辐射的基本特征进行了统计分析。分析表明:太阳紫外辐射在一天内早晚小,中午大,一年中6月份达到最强,与太阳天顶角的变化密切相关; UVB辐射积分通量远小于UVA辐射积分通量,其比值一般小于0.04,在天气晴好时下午大于上午; 雾能导致UVB辐射积分通量与UVA辐射积分通量的比值增大,其原因是雾对UVA辐射衰减强于对UVB辐射衰减; 云对太阳紫外辐射存在异常吸收。 相似文献
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基于近红外漫反射与漫透射光谱的玉米单倍体鉴别比较研究 总被引:1,自引:0,他引:1
使用JDSU公司的MicroNIR1700型微型近红外光谱仪,研究了适合进行单籽粒玉米单倍体鉴别的光谱测量方法。基于近红外光谱定性分析技术,比较了漫反射和漫透射两种情况下玉米单倍体鉴别的效果。光谱数据经过预处理后,采用PLS+OLDA特征提取算法,应用SVM建立玉米单倍体鉴别模型,分别统计漫反射和漫透射实验条件下,鉴别模型的正确识别率。在微型光谱仪内置光源漫反射的光谱测量方式下,不分胚面朝向,玉米单倍体籽粒平均识别率低于60%,不能有效鉴别玉米单倍体和多倍体。而采用外置光源对籽粒进行漫透射光谱测量方式,获得了平均正确识别率为93.2%的鉴别效果,并且模型稳定性好。实验结果表明,漫反射光谱仅能获得玉米籽粒表层信息,因此玉米籽粒胚面朝向严重影响漫反射光谱鉴别单倍体种子的效果;而漫透射光谱可以实现分析光程纵深信息全累加,能够得到样品内部的信息,因此对胚面朝向不敏感,能够有效地对随机摆放的玉米单倍体和多倍体进行识别。近红外方法能快速、无损地鉴别单倍体,并且微型光谱仪采集速度快,成本低,为实现实用化的自动鉴别提供了条件。 相似文献
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The properties of TiO2/polyamide 6 (PA6) and ZnO/PA6 nanocomposite filament yarns produced on a pilot-plant melt spinning machine were compared. Concentrated masterbatches were prepared using a twin screw extruder. Then continuous multifilament yarns were produced by blending nylon 6 chips and various amounts of the prepared masterbatches. Melt spinning was carried out at the spinning temperature of 265°C and take-up speed of 4000 m/min. As-spun multifilament yarns were then drawn and textured. Morphological properties of the produced yarns were studied. Thermal behavior and physical properties, including shrinkage and tensile properties, were measured. Weft-knitted fabrics were evaluated for their ultraviolet protection properties. Although both kinds of the nanoparticles had a positive effect on the ultraviolet protection properties of their nanocomposite fabrics as compared to pure PA6 fabric, the efficiency of the TiO2 nanoparticles was more than that of the ZnO ones for the same concentrations. The differences between the different properties of the two kinds of nanocomposites are discussed based on their interaction with the polymeric matrix, specific surface area, steric hindrance effect, and band gap energies. 相似文献
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Antonio Luiz Pereira de Siqueira Campos 《International Journal of Infrared and Millimeter Waves》2008,29(7):684-692
In this paper, a theoretical analysis of scattering from a doubly frequency selective surfaces (FSS) with dielectric and metallic
losses in the millimeter wave range is presented. The theoretical analysis involves the solution of the electric field integral
equation relating the induced current in the FSS in the presence of anisotropic dielectric layers. The method of moment is
employed to obtain numerical results. The frequency selective surface structure considered is composed by conducting patch
elements sandwiched between two anisotropic dielectric layers. Three different anisotropic materials are considered: Epsilam-10,
Alumina, and Sapphire. The sapphire presents low losses when compared with the other two dielectric materials. The most common
metals, as copper and aluminum, are considered in this analysis. None significant metallic losses were observed for any considered
metal. Numerical results are presented for the scattering characteristics and for dielectric and metallic losses parameters. 相似文献
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S. Koshevaya I. Moroz V. Grimalsky M. Tecpoyotl-Torres J. Escobedo-Alatorre J. Sánchez-Mondragón 《International Journal of Infrared and Millimeter Waves》2005,26(3):387-408
Volume and based on surface oriented integrated p-i-n-structures modulators have demonstrated high efficiency in millimeter wave range as quasi-optical modulators and phase shifters. These structures possess high modulation and high-speed properties; sustain great EM powers. However, the modulation characteristics of p-i-n modulators of both mentioned types in millimeter wave range have not been investigated yet. Here, a comparison and criteria of volume and integrated based on Si surface oriented structure modulators in millimeter wave range are presented. 相似文献
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实验证明了发散光照明模式和平行光照明模式标定的光谱辐照度响应度在定标误差范围内一致.在此基础上构建了由150W大功率氘灯、500W氙灯和球面反射镜组成的平行光光谱辐照度定标单元,该单元解决了大多数光谱辐射计由于在紫外波段响应度低、信噪比小导致的定标困难,而且其输出光谱辐照度在一定距离范围内变化很小从而减小了装调误差,提高了定标准确度.分两个波段标定了一台紫外光谱辐射计160nm~400nm波段光谱辐照度响应度,其中160nm~250nm定标误差4.6%,250nm~400nm定标误差2.4%. 相似文献