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1.
短波近红外光谱法分析酒中乙醇含量 总被引:25,自引:2,他引:23
使用短波近红外光谱和多变量校正技术快速准确地测定酒中乙醇含量. 研究了纯水、 乙醇以及乙醇和水混合体系的光谱特征. 用多元线性回归(MLR)和主成分回归(PCR )分析了二阶导数差谱数据. 该法分析酒样具有方便、 快速的优点. 相似文献
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研究了中华猕猴桃蛋白酶在不同浓度(V:V)乙醇存在下的内源荧光发射光谱、紫外差光谱、圆二色光谱(CD谱)及傅立叶变换红外光谱的变化,并测定了相应的活力变化,当乙醇浓度低于30%时,酶的荧光强度无明显变化,而乙醇浓度大于30%时,则酶荧光强度增大,且峰位略红移。在乙醇溶液中,酶的紫外差光谱在225~235nm内出现正峰,峰强度随乙醇浓度的增高基本表现为逐渐增大,峰位也逐渐蓝移。CD谱及红外光谱的测定结果表明低浓度乙醇中酶分子有序二级结构的减少及高浓度乙醇中β-折叠含量的增加.随乙醇浓度的增加.酶的活力表现为逐渐降低,且乙醇对酶的失活作用类似于竞争性抑制。 相似文献
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红外光谱自动定量分析 总被引:1,自引:0,他引:1
本文通过甲苯、甲乙酮二组分体系的红外光谱定量分析,编制了进行二组分体系自动定量分析的OBEY 程序,并对得到的标准方程进行了自动回归分析,结果较好。 相似文献
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采用激光喇曼方法,对甲醇和乙醇液体样品进行了喇曼光谱研究,得到了上述样品的喇曼光谱,并对其进行了归属.经过分析比较,给出了检测甲醇的特征谱线,为假酒鉴别、深入研究甲醇和乙醇的能级结构等提供了可供借鉴的参考. 相似文献
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用激光诱导荧光光谱技术研究了重度酒精中毒全血溶液的光谱特性,得到了光谱特征的变化规律,分析了乙醇在生物体内的代谢过程,以及乙醇对血细胞的作用机理.结果表明:重度酒精中毒全血溶液的荧光强度随时间衰变表现出明显的规律性,分析认为酒精作用于血细胞引起血液粘滞性以及血红细胞体积的增大,最终导致荧光强度的规律变化.研究结果对乙醇与生物组织特别是细胞的相互作用及其机理研究具有一定的参考意义. 相似文献
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水面光谱是利用遥感反演水体水质参数的数据基础,去除光谱中的噪声干扰,提高光谱的信号干扰比有助于改进水质参数的遥感反演的精度.本文选择叶绿素a浓度相同而悬浮泥沙浓度差异较大的两个水面光谱为代表,分析了核回归平滑方法对干扰的去除效果.假定干扰类型为4类,分别是正态分布、瑞利分布、指数分布和泊松分布,设定的干扰强度分为4级.利用蒙特卡洛模拟方法,通过500轮次的模拟计算了核回归平滑前后水面光谱的信号干扰比,并与多项式平滑、移动平均、局部回归和鲁棒性的局部回归平滑方法进行了比较.结果表明,不论干扰强度高或低,核回归平滑后的光谱均具有最高的信号干扰比.在四类干扰中,核回归平滑对于正态分布的干扰去除效果较好.与常用的多项式平滑方法相比,核回归平滑方法比较完整地保留了水面光谱中的峰谷位置信息,是一种值得推荐的提高水面光谱信号干扰比的方法. 相似文献
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采用正交设计法配制16组包含苯甲酸钠、山梨酸钾、对羟基苯甲酸甲酯钠3种防腐剂水性混合样品,分别测其紫外-可见(UV)光谱.果汁样品通过离心,取上清溶液,稀释一定的倍数测定其UV光谱.将果汁样品紫外光谱数据与模拟水样光谱融合得到增广光谱矩阵,采用独立成分分析(ICA)提取增广光谱矩阵中独立组分(IC)的浓度轮廓,将实际样品中3种防腐剂以外的其他成分作为背景加以扣除,以模拟标准样品3种防腐剂对应的浓度轮廓回归分析得到3种防腐剂测定的独立成分回归(ICR)模型,实际样品中防腐剂的IC值代入ICR模型预测得到相应防腐剂含量.将浓度IC轮廓进行最小二乘回归分析得到与其对应的光谱轮廓,可用作防腐剂与作为其他成分的背景信号的定性分析.方法用于市售某柠檬饮料中防腐剂测试分析,ICR模型的线性相关系数(R)均在0.99以上,测定结果与采用高效液相色谱法相当. 相似文献
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253.7 nm光辐照乙醇溶液荧光光谱分析 总被引:5,自引:0,他引:5
研究紫外光诱导不同浓度乙醇溶液的紫外光谱和荧光光谱,并对其产生机理和谱线特性进行探讨。实验结果和理论分析表明,当用紫外光照射乙醇溶液时,乙醇分子对253.7nm的紫外光产生吸收,并在400nm附近辐射出荧光;紫外光诱导不同浓度的乙醇溶液的荧光光谱特征几乎相同,只是荧光强度有较大变化。研究结果将为乙醇作为有机溶剂、催化剂、猝灭剂时对其它大分子产生荧光光谱及其特性的研究提供参考。 相似文献
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《江苏大学学报(自然科学版)》2015,(2)
为了研究乙醇水溶液近红外激光拉曼光谱随体积分数和温度的变化,首先通过便携式近红外激光拉曼光谱仪测得0~100%乙醇水溶液在10~30℃的拉曼光谱,然后将温度和拉曼光谱值一起用于建立体积分数预测模型,以提高其预测精度.结果表明:带有温度值的PLS模型相关系数(Rc)为0.997 6,校正均方根误差(RMSEC)为1.94,预测模型相关系数(Rp)均达到0.995 0以上,建立的乙醇水溶液联合模型性能较稳定,能够满足不同温度下乙醇水溶液体积分数的测定,满足实际在线检测的需要.进一步研究温度与乙醇水溶液的近红外拉曼光谱的关系,在体积分数0~100%每隔10%建立一个近红外拉曼光谱的温度PLS模型,得到11个模型的相关系数,R值在0.734 4和0.954 7之间,并且随着乙醇体积分数变大,R值越来越大. 相似文献
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Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness. 相似文献
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Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly. 相似文献
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理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。 相似文献
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Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well. 相似文献
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The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation. 相似文献
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As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death. 相似文献
17.
Miao Maosheng 《华南师范大学学报(自然科学版)》2014,(6)
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula- 相似文献
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Yang Weitao 《华南师范大学学报(自然科学版)》2014,46(6):137-138
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re- 相似文献
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Bernard Kirtman 《华南师范大学学报(自然科学版)》2014,(6)
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that 相似文献
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《上海师范大学学报(自然科学版)》2014,(5):550
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with 相似文献