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衰减全反射-紫外/可见光谱技术应用 被引量:2
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作者 朱红祥 柴欣生 +2 位作者 王双飞 宋海农 朱俊勇 《化学进展》 SCIE CAS CSCD 北大核心 2007年第2期414-419,共6页
本文对衰减全反射法(ATR)的光学测定原理、衰减全反射-紫外/可见光谱方法(ATR-UV)的特点以及它们在一些典型的工业过程溶液,如高浓度和含有大量固体颗粒和微乳液聚合等体系检测的应用进行了综述。ATR-UV光谱技术适宜实时地反馈工业过程... 本文对衰减全反射法(ATR)的光学测定原理、衰减全反射-紫外/可见光谱方法(ATR-UV)的特点以及它们在一些典型的工业过程溶液,如高浓度和含有大量固体颗粒和微乳液聚合等体系检测的应用进行了综述。ATR-UV光谱技术适宜实时地反馈工业过程溶液的组分改变和浓度变化,从而帮助我们了解该过程的进展。这些优良的特性能帮助我们开发在线的传感器,因此可用于监测许多典型的工业过程溶液。其方法简单、迅速,一般无需对试样进行预处理或稀释。ATR-UV作为光谱学测定的重要波段,其技术开发将在化工过程检测方面具有重要的意义。 展开更多
关键词 衰减全反射法 紫外/可见光谱 传感器 过程溶液
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不同成熟度猕猴桃糖度紫外/可见光谱检测 被引量:6
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作者 孟庆龙 尚静 +2 位作者 黄人帅 撒雄星 张艳 《食品研究与开发》 CAS 北大核心 2020年第21期167-172,共6页
猕猴桃糖度是判别其成熟度的关键指标,为构建预测不同成熟度猕猴桃糖度的最优模型。利用紫外/可见(200 nm^1000 nm)光谱采集系统获取不同成熟期“贵长”猕猴桃的反射光谱,比较3种光谱预处理方法[一阶导数、多元散射校正、标准正态变换(s... 猕猴桃糖度是判别其成熟度的关键指标,为构建预测不同成熟度猕猴桃糖度的最优模型。利用紫外/可见(200 nm^1000 nm)光谱采集系统获取不同成熟期“贵长”猕猴桃的反射光谱,比较3种光谱预处理方法[一阶导数、多元散射校正、标准正态变换(standard normal variation,SNV)]对光谱的预处理效果,应用竞争性自适应重加权算法(competitive adaptive reweighted sampling,CARS)从预处理后的全光谱中选取特征光谱,基于全光谱和特征光谱分别构建预测猕猴桃糖度的误差反向传播(error back propagation,BP)网络模型。结果表明:SNV预处理效果最优,采用CARS从1024个全波段中选取了29个特征波长,提升了预测模型的检测效率,构建的SNV-CARS-BP模型的预测性能最优,其预测集决定系数RP 2=0.901,均方根误差(root mean squares errors for prediction,RMSEP)为0.643%,剩余预测偏差(residual predictive deviation,RPD)为3.217。研究表明,采用紫外/可见光谱技术和BP网络检测猕猴桃糖度是可行的,SNV-CARS-BP模型最优。 展开更多
关键词 紫外/可见光谱 猕猴桃 糖度 误差反向传播网络 竞争性自适应重加权算法 无损检测
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光谱考察L-亮氨酸和银(I)离子的反应 被引量:2
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作者 申德君 游玉华 张朝平 《中国组织工程研究与临床康复》 CAS CSCD 北大核心 2008年第36期7071-7075,共5页
背景:金属离子与生物分子在溶液中可导致催化、电子转移、氧气运输等一系列的化学过程,近年来国内外对金属离子与氨基酸作用的研究,涉及Cu+和Cu2+-氨基酸的较为广泛,对L-亮氨酸与银(I)离子反应机制的研究还较为贫乏。目的:用紫外/可见... 背景:金属离子与生物分子在溶液中可导致催化、电子转移、氧气运输等一系列的化学过程,近年来国内外对金属离子与氨基酸作用的研究,涉及Cu+和Cu2+-氨基酸的较为广泛,对L-亮氨酸与银(I)离子反应机制的研究还较为贫乏。目的:用紫外/可见光谱和荧光光谱考察L-亮氨酸同银(I)离子间的相互作用。设计、时间及地点:金属离子与氨基酸水平光谱检测实验,于2004-09/2006-07在贵州大学完成。材料:L-亮氨酸由解放军第二军医大学药学系合成药物研究室提供,硝酸银为重庆无机化学试剂厂生产。UV-265型紫外分光光度计、RF-540荧光分光光度计为日本岛津产品。光源为150W的氙灯,激发和发射狭缝宽度均为10nm,为美国Orion公司产品。方法:向刻度离心管中依次加入0.02mol/L的L-亮氨酸溶液3.6mL,0.03mol/LAg(NH3)2NO3溶液0.8mL,1%三羟甲基氨基甲烷缓冲溶液1.2mL,4%十二烷基硫酸钠溶液0.4mL和0.1%HCHO溶液1.0mL,用HCl或NaOH调节pH值至7.06左右,震荡均匀后,反应90min,加12%醋酸1.5mL终止反应,最后终体积为10mL,即为L-亮氨与银(I)离子的配合物。主要观察指标:应用紫外/可见光谱和荧光光谱分析L-亮氨酸与银(I)离子的相互作用。结果:pH电位滴定法测定L-亮氨酸的离解常数为9.29,半n_法求得各L-亮氨酸-Ag配合物的逐级稳定常数为lgK1=11.04,lgK2=10.97。L-亮氨酸-银(I)离子体系的吸收峰发生明显红移,400nm^500nm区域的吸收呈现出宽而平滑的带,该体系受紫外光的影响大于可见光的影响,荧光强度随光照度的增加而不断减小。反应体系紫外/可见光谱的Soret带随溶液pH值的变化而改变,在光照度700Lux左右时其Soret带才出现吸收,且随光照度的增大、光照时间的增加其吸收也相应增强,荧光猝灭程度也越大。20℃L-亮氨酸-银(I)离子体系的电动电位为1.29×10-4V,动态猝灭常数为1.99×102L/mol,荧光猝灭速率常数为0.199×1011L/(mol·s)。结论:L-亮氨酸-银(I)离子的反应是光助化学反应,Ag+对亮氨酸-银(I)体系的荧光有猝灭作用。 展开更多
关键词 L-亮氨酸 银(I)离子 紫外/可见光谱 荧光光谱 光照度
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光谱法研究微乳体系中稀土钕离子(Ⅲ)与牛血清白蛋白的作用 被引量:4
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作者 张红梅 张朝平 《贵州大学学报(自然科学版)》 2004年第1期64-67,共4页
用紫外光谱研究了不同pH值下微乳体系中稀土Nd3+离子与牛血清白蛋白 (BSA)的作用。初步探讨了微乳体系中Nd3+与牛血清白蛋白作用的机理。同时 ,制备了它们的固态聚合物 ,测定了红外光谱特性 。
关键词 稀土金属离子 牛血清白蛋白 微乳液 紫外/可见光谱 红外光谱
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光谱法研究敏化的TiO_2纳米粒子光催化降解罗丹明B的途径 被引量:3
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作者 刘海龙 周艳 +2 位作者 黄鹤勇 冯玉英 王兴和 《南京师大学报(自然科学版)》 CAS CSCD 北大核心 2011年第1期64-67,共4页
采用sol-gel法制备了纳米氧化钛(TiO2),并用邻苯二甲酸(o-PTA)对TiO2进行敏化修饰,得到了邻苯二甲酸敏化纳米氧化钛(o-PTA/TiO2)催化剂.用傅里叶变化红外光谱(FT-IR)对其进行表征,发现邻苯二甲酸已经成功连接到TiO2的表面,并对其光催化... 采用sol-gel法制备了纳米氧化钛(TiO2),并用邻苯二甲酸(o-PTA)对TiO2进行敏化修饰,得到了邻苯二甲酸敏化纳米氧化钛(o-PTA/TiO2)催化剂.用傅里叶变化红外光谱(FT-IR)对其进行表征,发现邻苯二甲酸已经成功连接到TiO2的表面,并对其光催化性能进行了研究.以罗丹明B(RhB)为催化降解目标物,采用紫外/可见光谱(UV-V is)法和荧光光谱(FL)法对催化降解RhB的产物进行研究,结果显示,在可见光下TiO2催化降解RhB时,是直接矿化RhB;同条件下o-PTA/TiO2催化降解RhB时,是分步降解.对两种光催化路径的探究,可以为光催化降解以RhB为代表的一系列染料提供理论基础.研究表明,无论采用紫外/可见光谱法还是采用荧光光谱法对RhB的降解产物进行表征,都可以得到一致的结果,方法简便易操作. 展开更多
关键词 紫外/可见光谱 荧光光谱 敏化氧化钛 罗丹明B
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基于金纳米粒子比色法检测全氟辛烷磺酸 被引量:8
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作者 丛妍斌 郑永红 +2 位作者 郑莉 吴飞 谭克俊 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2015年第1期189-192,共4页
全氟辛烷磺酸(perfluorooctanesulfonate,PFOS)具有遗传毒性、生物蓄积性和持久性,且难以降解,因此对其进行分析研究具有十分重要的意义。实验发现,PFOS能使巯基乙胺包被的正电金纳米粒子发生聚集,引起体系吸收信号及颜色改变,据此建... 全氟辛烷磺酸(perfluorooctanesulfonate,PFOS)具有遗传毒性、生物蓄积性和持久性,且难以降解,因此对其进行分析研究具有十分重要的意义。实验发现,PFOS能使巯基乙胺包被的正电金纳米粒子发生聚集,引起体系吸收信号及颜色改变,据此建立了检测PFOS的紫外-可见分光光度法及比色法。线性方程为A=-0.346+0.049c,相关系数为0.992 4,线性范围0.8~8.0μmol·L^-1,检出限为80nmol·L^-1。研究表明:金纳米粒子在524nm有特征吸收峰,在650nm处有较宽吸收峰,PFOS的加入会使金纳米粒子524nm吸收峰降低,650nm吸收峰增强,随着PFOS浓度增大,体系颜色由酒红色向红紫色变化。表征了体系的扫描电镜显微成像(SEM)及紫外吸收光谱,考察了金纳米粒子的聚集情况,实验缓冲体系选用pH5.0的HAc-NaAc缓冲溶液。本方法具有简单、快速等特点,可通过肉眼观察颜色变化来实现对环境污染物PFOS的检测。本方法用于实际水样中PFOS的检测,RSD≤4.4%。 展开更多
关键词 全氟辛烷磺酸 金纳米粒子 比色法 紫外/可见光谱
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基于主成分回归的猕猴桃可溶性固形物无损检测 被引量:9
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作者 孟庆龙 尚静 +2 位作者 黄人帅 杨欣 张艳 《包装工程》 CAS 北大核心 2021年第3期19-24,共6页
目的为实现猕猴桃可溶性固形物含量的快速无损检测。方法实验采用反射式光谱采集系统获取不同成熟期“贵长”猕猴桃的反射光谱。比较3种光谱预处理方法(标准正态变换、多元散射校正以及二阶导数)对回归预测模型的影响;采用主成分分析对... 目的为实现猕猴桃可溶性固形物含量的快速无损检测。方法实验采用反射式光谱采集系统获取不同成熟期“贵长”猕猴桃的反射光谱。比较3种光谱预处理方法(标准正态变换、多元散射校正以及二阶导数)对回归预测模型的影响;采用主成分分析对预处理后的光谱数据进行降维,并基于提取的特征变量,建立猕猴桃可溶性固形物含量的回归预测模型。结果采用主成分分析,从1024个全光谱波段中提取了前16个主成分作为特征变量;基于特征变量建立的回归预测模型具有较好的预测性能,其预测集决定系数R2 P=0.88,剩余预测偏差为2.94。结论基于紫外/可见光谱结合主成分回归可以很好地预测猕猴桃可溶性固形物含量。 展开更多
关键词 紫外/可见光谱 猕猴桃 可溶性固形物 主成分回归 无损检测
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Isolation of a Prodigiosin-producing Strain and Analysis of It's Pigments 被引量:1
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作者 段学辉 傅奇 +2 位作者 魏斌 郭炳其 贾奎艳 《Agricultural Science & Technology》 CAS 2010年第11期25-27,72,共4页
[Objective] The aim was to isolate a prodigiosin producing strain and study its pigment fractions.[Method] Red pigment-producing bacteria was identified by physiological and biochemical characteristics after isolation... [Objective] The aim was to isolate a prodigiosin producing strain and study its pigment fractions.[Method] Red pigment-producing bacteria was identified by physiological and biochemical characteristics after isolation in plate.By using column chromatography and thin-layer chromatography,pigment fractions were separated and purified from the extractives of the strain after fermentation in flask,and then pigment fractions were analyzed via UV-Vis and LC/MS.[Result] A red pigment-producing Serratia marcescens strain NS-17 sampled from soil of Nanchang was isolated and identified.2 pigment fractions showing similar UV-Vis and LC/MS characters were separated and purified,the characters of fraction 1 were identical to those of prodigiosin,while fraction 2 showed a special UV-Vis absorption spectrum that had not been reported.[Conclusion] A prodigiosin-producing Serratia marcescens strain NS-17 and its 2 pigment fractions were isolated. 展开更多
关键词 Red pigment Serratia marcescens PRODIGIOSIN UV-VIS LC/MS
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丙烯酸-2,4,6-三硝基苯乙酯的合成及热分解 被引量:2
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作者 刘强强 金波 +3 位作者 彭汝芳 舒远杰 楚士晋 董海山 《含能材料》 EI CAS CSCD 北大核心 2012年第5期579-582,共4页
以TNT、甲醛为原料,在弱碱性条件下反应合成得到2,4,6-三硝基苯乙醇(PicCH2CH2OH);PicCH2CH2OH在浓硫酸催化下和丙烯酸在甲苯中回流反应24h,合成得到丙烯酸-2,4,6-三硝基苯乙酯,产率为62%。采用紫外可见光谱(UV-Vis)、核磁共振氢谱(1HN... 以TNT、甲醛为原料,在弱碱性条件下反应合成得到2,4,6-三硝基苯乙醇(PicCH2CH2OH);PicCH2CH2OH在浓硫酸催化下和丙烯酸在甲苯中回流反应24h,合成得到丙烯酸-2,4,6-三硝基苯乙酯,产率为62%。采用紫外可见光谱(UV-Vis)、核磁共振氢谱(1HNMR)、红外光谱(FTIR)、质谱(MS)以及元素分析等对产物结构进行了表征。利用热重分析(TG)对产物热稳定性进行了研究,采用Kissinger方法和Ozawa方法计算其热分解活化能Ea分别为99.78,102.96kJ·mol-1。 展开更多
关键词 有机化学 2 4 6-三硝基苯乙醇 丙烯酸-2 4 6-三硝基苯乙酯 热稳定性 活化能
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Contacted Ion Pairs in Aqueous CuCl2 by the Combination of Ratio Spectra, Difference Spectra, Second Order Difference Spectra in the UV-Visible Spectra
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作者 鞠思文 张宁 +4 位作者 王志强 张睿挺 曾德文 邵晓鹏 林珂 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2017年第6期657-663,I0001,I0002,共9页
The microstructure of aqueous CuCl2 has been studied through lots of technologies for many years; however, it remains a controversial subject. In this study, a new spectroscopic method has been proposed to analyze the... The microstructure of aqueous CuCl2 has been studied through lots of technologies for many years; however, it remains a controversial subject. In this study, a new spectroscopic method has been proposed to analyze the UV-visible spectra of thin fihn of CuCl2/H2O solutions at different concentrations. This method is the combination of ratio spectra, difference spectra and second order difference spectra. By using this method, two new bands at -230 and -380 nm are obviously observed. The bands are assigned as the contacted ion pairs [CuCl3(H2O)n]- or [CuCl4(H2O)n]2-, which demonstrates that ion pairs exist in the CuCl2/H2O solution. Such finding agrees with the recent theoretical spectra obtained by time-dependent density functional theory. Furthermore, the populations of the contacted ion pairs are discussed. This study not only offers the direct spectroscopic evidence of [CuCl3(H2O)n]- or [CuCl4(H2O)n]2- in aqueous CuCl2, but also suggests that the spec- troscopic analysis method is powerful to extract the weak bands in a strong overlapping spectrum. 展开更多
关键词 UV-visible spectroscopy Ratio spectra Difference spectra CuCl2/H2O solution Ion pair
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Identification of Superoxide O2^- during KNO3-NaNO2-NaNO3 Salt by Electron UV-Vis Absorption Spectroscopy Thermal Decomposition of Molten Paramagnetic Resonance and
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作者 刘舒婷 苏涛 +2 位作者 张鹏 费泽杰 刘洪涛 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2017年第4期372-378,I0001,共8页
On account of excellent thermal physical properties, molten nitrates/nitrites salt has been widely employed in heat transfer and thermal storage industry, especially in concentrated solar power system. The thermal sta... On account of excellent thermal physical properties, molten nitrates/nitrites salt has been widely employed in heat transfer and thermal storage industry, especially in concentrated solar power system. The thermal stability study of molten nitrate/nitrite salt is of great importance for this system, and the decomposition mechanism is the most complicated part of it. The oxide species O2^2- and O2^- were considered as intermediates in molten KNO3-NaNO3 while hard to been detected in high temperature molten salt due to their trace concentration and low stability. In this work, the homemade in situ high temperature UV- Vis instrument and a commercial electron paramagnetic resonance were utilized to supply evidence for the formation of superoxide during a slow decomposition process of heat transfer salt (HTS, 53 wt% KNO3/40 wt% NaNO2/7 wt% NaNO3). It is found that the superoxide is more easily generated from molten NaNO2 compared to NaNO3, and it has an absorption band at 420-440 nm in HTS which red shifts as temperature increases. The band is assigned to charge-transfer transition in NaO2 or KO2, responsible for the yellow color of the molten nitrate/nitrite salt. Furthermore, the UV absorption bands of molten NaNO2 and NANO3 are also obtained and compared with that of HTS. 展开更多
关键词 Superoxide Decomposition of heat transfer salt High temperature UV-visible Electron paramagnetic resonance
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A comprehensive analysis of various structural parameters of Indian coals with the aid of advanced analytical tools 被引量:5
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作者 B. Manoj 《International Journal of Coal Science & Technology》 EI 2016年第2期123-132,共10页
An exhaustive structural analysis was carried out on three Indian coals (ranging from sub-bituminous to high volatile bituminous coal) using a range of advanced characterization tools. Detailed investigations were c... An exhaustive structural analysis was carried out on three Indian coals (ranging from sub-bituminous to high volatile bituminous coal) using a range of advanced characterization tools. Detailed investigations were carded out using UV-Visible spectroscopy, X-ray diffraction, scanning electron microscopy coupled energy dispersive spectroscopy, Raman spectroscopy and Fourier transform infrared spectroscopy. The X-ray and Raman peaks were deconvoluted and analyzed in details. Coal crystallites possess turbostratic structure, whose crystallite diameter and height increase with rank. The tJdC ratio plotted against aromaticity exhibited a decreasing trend, confirming the graphitization of coal upon leaching. It is also found that, with the increase of coal rank, the dependency of I20/I26 on La is saturated, due to the increase in average size of sp2 nanoclusters. In Raman spectra, the observed G peak (1585 cm^-1) and the D2 band arises from graphitic lattices. In IR spectrum, two distinct peaks at 2850 and 2920 cm i are attributed to the symmetric and asymmetric -CH2 stretching vibrations. The intense peak at - 1620 cm^-1, is either attributed to the aromatic ring stretching of C=C nucleus. 展开更多
关键词 Coal structure Spectroscopic tools X-ray diffraction Graphene layers
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UV enhanced gas–solid synthesis of chlorinated poly vinyl chloride characterized by a UV–Vis online analysis method 被引量:2
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作者 杨千里 卢巍 +2 位作者 白琳 颜彬航 程易 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第6期1052-1059,共8页
Dynamic characteristics of UV enhanced gas–solid PVC chlorination process were revealed by a UV–Vis spectral online analysis method. Experimental results showed an instantaneous increase of the chlorination rate as ... Dynamic characteristics of UV enhanced gas–solid PVC chlorination process were revealed by a UV–Vis spectral online analysis method. Experimental results showed an instantaneous increase of the chlorination rate as soon as UV light was affiliated, which demonstrated the intensified effect of UV radiation on PVC chlorination directly.Different affiliation methods of UV light were then studied, proving that continuous UV radiation could enhance the chlorination process significantly while intermittent UV radiation was able to initiate the chlorination reaction once it was conducted. Besides, experiments were carried out to study the influences of parameters on the chlorination process such as UV wavelength, chlorination temperature, partial pressure of chlorine gas and PVC raw materials. Among all the parameters, chlorination temperature and partial pressure of chlorine gas were testified as two key factors to determine the chlorination performance. Thermal analysis of CPVC products showed that their corresponding properties such as the glass transition temperature(Tg) and the homogeneity of chlorine distribution in polymer phase were improved with the increase of chlorine content. 展开更多
关键词 Polymer PHOTOCHEMISTRY UV-Vis online analysis Dynamic characteristics Chlorinated poly vinyl chloride
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Electric Conductivity Study of o-Substituted Phenoxo Iron (Ⅲ) Complexes 被引量:2
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作者 Ramadan Ali Bawa 《Journal of Chemistry and Chemical Engineering》 2010年第5期54-58,共5页
The coordination nature of a number of substituted sodiumphenoxides to iron (Ⅲ) ion has been studied. The o-nitrosodiumphenoxide was found to have different coordination behaviour from that the sodium salts of sali... The coordination nature of a number of substituted sodiumphenoxides to iron (Ⅲ) ion has been studied. The o-nitrosodiumphenoxide was found to have different coordination behaviour from that the sodium salts of salicylic acid and methylsalicylate showed. The structure of the complexes, the number of the ligands being coordinated to the metal ion, has also been determined by titration, uv-vis spectroscopy, atomic absorption and the flame test. In addition, other sodium phenoxides were also involved in this study for comparison. An electric conductivity study on the resulting complexes was carried out and all complexes were found to be semiconductors. 展开更多
关键词 Iron (Ⅲ) ion COMPLEXES COORDINATION electric conductivity SEMICONDUCTORS
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Iron(Ⅱ) tetrasulfophthalocyanine mimetic enzymatic synthesis of conducting polyaniline in micellar system 被引量:2
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作者 胡兴 刘惠 邹国林 《Journal of Central South University》 SCIE EI CAS 2009年第5期743-748,共6页
Iron(Ⅱ) tetrasulfophthalocyanine(FeTSPc) ,as a novel mimetic enzyme of peroxidase,was used in the synthesis of a conducting polyaniline(PANI) /sodium dodecylsulfate(SDS) complex in SDS aqueous micellar solutions. The... Iron(Ⅱ) tetrasulfophthalocyanine(FeTSPc) ,as a novel mimetic enzyme of peroxidase,was used in the synthesis of a conducting polyaniline(PANI) /sodium dodecylsulfate(SDS) complex in SDS aqueous micellar solutions. The effects of pH,concentrations of aniline,SDS and H2O2,and reaction time on polymerization of aniline were studied in this case as shown by UV-Vis absorption spectroscopy. The results show that a wide range of pH(0.5-4.0) is required to produce the conducting PANI,and the optimal pH is 1.0 in SDS micelle. The optimal concentrations of aniline,SDS and H2O2 in feed,and reaction time in this case for the production of conducting PANI are respectively 10 mmol/L,10 mmol/L,25 mmol/L,and 15 h. FT-IR spectrum,elemental analysis,conductivity,cyclic voltammetry and thermogravimetric analysis confirm the thermal stability and electroactive form of PANI. 展开更多
关键词 iron( tetrasulfophthalocyanine POLYANILINE mimetic enzyme CONDUCTIVITY MICELLE
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Adsorption properties of CFBC ash-cement pastes as compared with PCC fly ash-cement pastes 被引量:4
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作者 Zhijuan Wang Yuanming Song 《International Journal of Coal Science & Technology》 EI 2016年第1期62-67,共6页
Circulating fluidized bed combustion (CFBC) ash can be potentially used as supplementary cementitious materials for concrete production due to its desirable pozzolanic activity. The adsorption properties of CFBC ash... Circulating fluidized bed combustion (CFBC) ash can be potentially used as supplementary cementitious materials for concrete production due to its desirable pozzolanic activity. The adsorption properties of CFBC ash-cement pastes were studied, and ordinary pulverized coal combustion (PCC) fly ash-cement pastes were used as control. The water-adsorption and superplasticizer (SP)-adsorption properties of the pastes were evaluated by water demand and UV-visible absorption spectroscopy respectively. The results show that CFBC ash-cement system has greater compressive strength as compared with PCC fly ash-cement system at a given curing age, although the water demand of the former is significantly higher than that of the latter. CFBC ash-cement pastes possess higher adsorption ability of aliphatic SP than PCC fly ash-cement pastes and the adsorption amount increases with an increase in ash replacement ratio. CFBC ash- cement pastes exhibit lower workability with higher slump loss. It is concluded that CFBC ash can be potentially used as supplementary cementitious material in concrete production, but the mix design of CFBC ash concrete needs to be appropriately adjusted. It is suggested that CFBC ash is used for the production of the concrete needing low flowability. 展开更多
关键词 CFBC ash - Coal ash CONCRETE ADSORPTION SUPERPLASTICIZER FLOWABILITY
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Spectroscopic Studies of the Interaction of Silver Nanoparticles with Methylene Blue 被引量:1
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作者 董川 张俊 周山代子 《Journal of Measurement Science and Instrumentation》 CAS 2010年第1期61-64,共4页
The interaction between silver nanoparticles and Methylene Blue (MB) is studied by UV-Vis spectroscopy and fluorescence spec- trometry. The UV-Vis absorption of the silver nanoparticles changes dramatically with the... The interaction between silver nanoparticles and Methylene Blue (MB) is studied by UV-Vis spectroscopy and fluorescence spec- trometry. The UV-Vis absorption of the silver nanoparticles changes dramatically with the addition of MB. However, no obvious changes of absorption spectra of MB are observed when silver colloids are added into the MB solution. In the presence of surfactant SDS, the catalysis of the silver nanoparticles in the reduction of MB by sodium borohydride is exhibited by UV-Vis and fluorescence spectrosopy of MB displaying faster response compared with the absence of the silver nanoparticles. The results show that the activity of surfactant SDS modified silver nanoparticles is great and a strong physical adsorption to MB exists. 展开更多
关键词 silver nanoparticles methylene blue INTERACTION UV- Vis absorption spectra
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UV-Vis Spectrophotometry and AFM Observation of Diethyl Dithiophosphate Adsorption on Chalcopyrite at Varied pHs 被引量:1
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作者 Himawan T. B. M. Petrus Tsuyoshi Hirajima +1 位作者 Keiko Sasaki Hideyuki Okamoto 《Journal of Chemistry and Chemical Engineering》 2011年第11期1006-1013,共8页
Adsorption of diehtyl dithiophosphate on chalcopyrite has been studied using UV-visible spectroscopy at pH values of 4, 6, and 9. It was found that the adsorption of diethyl dithiophosphate decreased with the increasi... Adsorption of diehtyl dithiophosphate on chalcopyrite has been studied using UV-visible spectroscopy at pH values of 4, 6, and 9. It was found that the adsorption of diethyl dithiophosphate decreased with the increasing pH treatments. The inhibition of diethyl dithiophosphate adsorption was found prominent in higher pH as a result of metal hydroxide species formation onto chalcopyrite surface. First order kinetic has been proposed and represented the adsorption mechanism. Flotation test using Hallimond tube has also been conducted and the results were consistent with the proposed mechanism. Furthermore, the morphological changes of the treated chalcopyrite were observed using Atomic Force Microscopy (AFM) showing the propensity of growth of islands, the new surfaces as products of the reaction. The hydrophobicity was measured in the form of force of adhesion. The results resembled with the approached mechanism. 展开更多
关键词 CHALCOPYRITE diethyl dithiophosphate ADSORPTION kinetic study AFM FLOATABILITY
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Aroma Properties of Selected Local Spices of Akwa Ibom State of Nigeria
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作者 E. U .U. Ituen A. F. Alonge 《Journal of Agricultural Science and Technology(B)》 2011年第7期989-997,共9页
Some famous local spices were selected to determine their potentials in terms of their aroma and utilization. They included Tea Bush (Ocimum basilicum), Guinea Black Pepper (Piper guineense), African Pepper (Xylo... Some famous local spices were selected to determine their potentials in terms of their aroma and utilization. They included Tea Bush (Ocimum basilicum), Guinea Black Pepper (Piper guineense), African Pepper (Xylopia aethiopica), Alden Tree (Tetrapleura tetraptera) and the African Meg Nut or Onion Tree (Blighia unijugata). Essential oils were extracted from the samples and used for aroma absorption test in a uv-visible spectrometer V2.03. The intensity of aroma was indicated at some peak values of absorption at particular wavelengths. The compounds responsible for the aroma at this peak values were identified by matching their wavelengths with those of known compounds at similar wavelengths of absorption. Thus, a compound such as Quinoline that has hot strong aroma and little bleaching effect was proved to be present in Guinea black pepper ;at the wavelength of 313.0 nm. Benzene with hot strong aroma and flammable effect was also indicated in this spice at the wavelength of 253.0 rim. Proximate analysis carried out showed that these spices have high nutritive values. Some of them such as Guinea black pepper, African Nutmeg and Ethiopian (African) pepper had high ether extract of 20.01, 25.97 and 31.25 respectively, and could be regarded as oil seeds, they contain much of essential oils. 展开更多
关键词 Absorption WAVELENGTH aroma properties proximate analysis spice.
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Electrochemical Tuning by Polarized UV Light Induced Molecular Orientation of Chiral Salen-type Mn(II) and Co(II) Complexes in an Albumin Matrix
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作者 Eirika Tsuda Yuya Mitsumoto +4 位作者 Kazuya Takakura Nobumitsu Sunaga Takashiro Akitsu Taro Konomi Masahiro Katoh 《Journal of Chemistry and Chemical Engineering》 2016年第2期53-59,共7页
The authors have prepared supramolecular systems as artificial metalloproteins composed of several chiral salen-type Mn(II) and Co(II) complexes in a HSA (human serum albumin) matrix. The docking was discussed b... The authors have prepared supramolecular systems as artificial metalloproteins composed of several chiral salen-type Mn(II) and Co(II) complexes in a HSA (human serum albumin) matrix. The docking was discussed by UV-vis spectral changes and a ligand-protein docking simulation program. After linearly polarized UV light irradiation, that anisotropy of molecular orientation of the complexes increased was confirmed by polarized IR spectra. The authors have observed that the electrochemical behavior of the aligned complexes incorporating diphenyl groups in HSA can be tuned without UV radiation damage of HSA higher structures. 展开更多
关键词 Redox potential Schiff base Mn(II) complex Co(II) complex albumin.
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