共查询到20条相似文献,搜索用时 0 毫秒
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B. L. Diffey 《Photochemistry and photobiology》1994,60(4):380-382
Abstract This study compared how well minimal erythema doses predicted using the reference action spectrum for UV erythema proposed by the International Commission on Illumination (CIE) in 1987 agreed with those observed in phototesting a large number of subjects with normal responses to sunlight to six different wavelengths of UV radiation (UVR) between 300 and 400 nm. It was found that, within the limits of experimental error, the hypothesis that the CIE reference action spectrum is a valid predictor of the erythemal effectiveness of different wavelengths of UVR could not be dismissed. There is no strong reason, therefore, why the CIE action spectrum should not continue to be used as a reference to compare the erythemal effectivenesses of different broadband sources. However, close examination of the residuals from the regression analysis suggested that the erythemal sensitivity of skin at longer UV wavelengths (>350 nm) in the population studied here is greater than predicted from the CIE reference action spectrum. 相似文献
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影响离子色谱测量准确性的因素 总被引:2,自引:0,他引:2
介绍了离子色谱测量过程中色谱条件的变化、样品前处理方法和操作过程等因素对测量结果准确性的影响,提出了相应的解决措施和校准方法.以实际样品测定为例介绍了样品前处理过程中待测组分浓度和形态的变化,对定量分析结果造成的误差及修正方法. 相似文献
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脱铝方法对富硅丝光沸石性质的影响 总被引:1,自引:0,他引:1
本文用酸浸取, 水蒸汽处理加酸浸取和(NH_4)_2SiF_6类质同晶取代三种不同方法制备了Si/Al比为6—15左右的富硅丝光沸石样品, 并且用多种实验手段测定了它们的相对结晶度, 羟基空穴摩尔分数, 晶胞参数, 红外反对称伸缩振动频率, 热稳定性和水热稳定性, 表面酸性和催化活性。实验结果表明脱铝方法对富硅丝光沸石的性质有很大的影响, 不同的脱铝方法得到的沸石样品在许多方面有显著的差别。文中对此进行了详细的描述, 并对产生这些差别的结构因素讲行了讨论。 相似文献
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<正> 分子间形成氢键对低分子化合物及高分子化合物物理性质的影响研究得比较多,对低分子有机化合物化学性质的影响研究也进行了大量工作。于宝善等研究表明单体分子间形成氢键对单体的自由基聚合能力是有影响的。 上述研究都是在芳香族酰胺及脂肪族酰胺类单体的液相本体聚合或熔融态的本体聚 相似文献
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热处理对尼龙1010结构影响研究 总被引:2,自引:0,他引:2
采用WAXD,SAXS方法研究了热处理对尼龙1010聚集态结构的影响.结果表明,在温度为175℃左右对样品进行退火处理可获得较完善的结晶.利用Wc.x~T关系曲线外推法得到尼龙1010样品的Tg大约为58℃.根据一维电子密度相关函数法求得了系列样品在所研究条件下的结晶片层厚,过渡层厚,长周期和结晶非晶相间的密度差.得到了不同退火条件尼龙1010样品的结晶相密度ρc. 相似文献
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G. Blasse 《Photochemistry and photobiology》1990,52(2):417-422
The nature of the ligands determines the luminescence properties of the central metal ion. This is illustrated on the following examples: (i) nonradiative transitions in the strong coupling model; (ii) nonradiative transitions in the weak coupling model; (iii) energy transfer from ligand to central ion. Several applications are dealt with. The cryptand ligands appear to play a special role. 相似文献
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叶绿素是绿色植物中吸收太阳能进行光合作用的主要色素,它在可见光范围内有很好的吸收特性[1]。人们为了充分利用太阳能为人类造福开始了光合作用模拟,70年代后以叶绿素为光敏剂的研究成了科学家的热门课题。 相似文献
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研究了彩色显影液中亚硫酸钠对含内偶青成色剂的卤化银单层片的彩色成像过程的各化学反应、青染料影像的有害吸收以及染料云形态的影响,结果表明亚硫酸钠能(1)提高银影像的形成速度;(2)降低成色剂的表观偶合效率;(3)增加青染料影像的有害吸收;(4)使染料云缩小并且使染料云的分布变窄。 相似文献
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本文研究了PBT结晶的熔化行为及非晶性组分PSF的加入对PBT结晶度及熔化行为的影响。结果表明:PBT结晶熔化时的DSC双峰图为多重熔化行为而非多晶型的结果;PSF的加入对PBT结晶度影响不大,但对多重熔化行为有明显影响。此乃PSF无定形组分加入后,使PBT结晶速率减慢而形成更完善的PBT结晶之缘故。 相似文献
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M. Dolz F. González M. Herráez O. Díez-Sales 《Journal of Dispersion Science and Technology》2013,34(2):189-205
A study has been made of the influence of physical factors such as temperature, agitation time and shear rate upon the rheological behaviour of hydrogels composed of 2·5% microcrystalline cellulose -sodium carboxymethyl cellulose (Avicel RC 591(r), American Viscose Div., FMC Corp.) and different percentages of corn starch (0-3% by weight, w/w). 相似文献
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兰波 《理化检验(化学分册)》2000,36(4):170-171,178
石墨电极的纯度对光谱分析的影响只是在一些书中提及,表作试验研究和分析,对电极的纯度的检验未作有效论述。文中就此问题提出了作者的见解,拟定了检验电极纯度的方法。 相似文献
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S. Chakraborty R. Nandi M. Maiti B. Achari S. Bandyopadhyay 《Photochemistry and photobiology》1989,50(5):685-689
Abstract— The absorption and fluorescence characteristics of aristolochic acid, aristololactam, N- methyl aristololactam and aristololactam-ß-D-glucoside have been studied at neutral pH. Absorption and fluorescence characteristics of the alkaloids have been evaluated from their UV-visible spectra, the fluorescence emission and excitation spectra, and quantum yields. The effect of pH in the range 1.0–14.0 on the structure of the alkaloids has also been investigated. A pH dependent reversible change in the absorption and fluorescence spectra is obtained with aristololactam and aristololactam-ß-D-glucoside. It is suggested that the pH dependent properties of aristololactam and aristololactam-ß-D-glucoside are due to the formation of lactam ⇄ lactim and phenanthrenic lactam ⇄ amino phenanthrenic acid, respectively. 相似文献