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哈龙1301分子在外电场中的光谱特征和解离特性 被引量:16
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作者 刘玉柱 李相鸿 +3 位作者 王俊锋 管跃 金峰 秦朝朝 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2017年第3期679-684,共6页
哈龙1301(三氟溴甲烷)在太阳光辐射下解离生成破坏臭氧的溴自由基,严重破坏大气臭氧层,采用有效的措施对哈龙1301排放前进行降解很有必要。利用密度泛函理论(DFT)在B3LYP/6~311G++(d,p)水平上研究了外电场(0~0.03 a.u.)作用下哈龙130... 哈龙1301(三氟溴甲烷)在太阳光辐射下解离生成破坏臭氧的溴自由基,严重破坏大气臭氧层,采用有效的措施对哈龙1301排放前进行降解很有必要。利用密度泛函理论(DFT)在B3LYP/6~311G++(d,p)水平上研究了外电场(0~0.03 a.u.)作用下哈龙1301分子的解离特性和光谱特征,包括总能量,键长,电偶极矩,LUMO-HOMO能隙,红外光谱以及解离势能面等。计算结果表明,在C——Br键连线Z方向上,外电场从0逐渐增加到0.03 a.u.时,分子体系能量逐渐减小,偶极矩在刚开始表现为减小然后单调增大,HOMO-LUMO能隙E_G呈现单调递减的趋势,C——Br键键长逐渐增大,C——F键键长逐渐减小。外电场对CF_3Br分子不同振动模式的红外光谱影响不同。在外电场作用逐渐增强下,解离特性表现为:CF_3Br分子的C——Br键方向扫描得到的势能曲线的束缚状态逐渐被消除,势垒逐渐变小最后消失。计算发现强度为0.03 a.u.的外电场足够使得CF_3Br分子发生C——Br键断裂而降解,该结果为保护环境而对哈龙进行电场降解提供重要参考依据。 展开更多
关键词 哈龙1301 DFT 降解 外电场 光谱
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激光诱导击穿光谱技术快速探测煤灰中的重金属锌(英文) 被引量:4
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作者 周冯斌 刘玉柱 +5 位作者 丁宇 尹文怡 祝若松 张启航 金峰 章炎麟 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2019年第6期1980-1985,共6页
煤灰的成分指的是煤中矿物质的完全燃烧,产生各种金属和非金属氧化物和盐,这是使用煤时的重要参数。煤被广泛用于生产和人民生活,作为重要的能源物质。大量来自燃煤燃烧的煤尘(煤灰)被释放到大气中并与大气中的各种物质相互作用而形成... 煤灰的成分指的是煤中矿物质的完全燃烧,产生各种金属和非金属氧化物和盐,这是使用煤时的重要参数。煤被广泛用于生产和人民生活,作为重要的能源物质。大量来自燃煤燃烧的煤尘(煤灰)被释放到大气中并与大气中的各种物质相互作用而形成雾霾。煤灰中的金属氧化物和空气中的小液滴之间发生一系列物理化学反应,这导致了雾霾的形成。在实验中,采用激光诱导击穿光谱(LIBS)分析煤灰中的元素。实验样品由某钢铁公司提供,分为七个样品,并标上序号。样品分别加入蒸馏水和0.1‰,0.2‰,0.2%,0.4%,0.8%,1%硫酸锌溶液,分别用1~7号标记。为了获得更好的LIBS信号,样品被研磨为粉末状,并使用蒸馏水使硫酸锌与煤灰充分混合。通过使用压片机将煤灰压制成10mm直径和10mm厚的煤灰块。为获得准确的元素结果,X射线荧光光谱也被用作参考,并且原始样品不含锌元素。由于光谱分析和波长漂移现象的不确定性,因此实验中,分别选择了铁,钙,钛和铝四种高纯单质。在相同的实验条件下,将四条测量的元素谱线与NIST原子光谱数据库中相应的谱图比较。实验中的所有光谱根据波长差或偏移进行校正。此时,纯单质的元素谱线可以与样品的光谱对齐。当元素谱中的特征线与样品中的谱线对齐时,样品就可以被识别和确认。由于铝元素与目标元素具有相似的化学和物理性质,铝元素是煤灰和地壳中的主要元素之一,具有中等的光谱强度。因此将铝元素作为内标元素,运用内标校准方法来确定样品中锌的浓度。模拟含锌大气气溶胶是通过向煤灰中添加含锌元素来实现的。还有一些其他的金属元素,包括铁,钙,锰,钛和铝也被用来加入煤灰中,用以模拟大气气溶胶。两种方法的相对差异分别为1.78%,3.39%,5.17%,0.20%。造成差异的原因可能是由于光谱仪缺乏分辨率或背景噪声的影响,这是可能导致测量误差的原因之一。由于实验室条件的限制,无法确定基底是否会影响实验结果,这将在未来的实验中得到进一步的证实。实验拟合曲线测得煤灰中锌的线性相关系数为0.99572,这表明可以通过粗略估算锌的激光强度来估计煤灰中的锌含量的实现。实验结果证明LIBS技术可用于煤灰中金属元素的快速检测,为基于锌含量的大气环境检测提供了一种新方法。在建立元素的校准曲线后,LIBS技术将来可以用来进行更快速,更准确的定量分析。 展开更多
关键词 激光诱导击穿光谱 煤灰 重金属 气溶胶 定量分析
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Electronic Structure and Physical Characteristics of Dioxin Under External Electric Field 被引量:2
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作者 Wenyi Yin Xiangyun Zhang +4 位作者 Bumaliya Abulimiti Yuzhu Liu Yihui Yan Fengbin Zhou Feng Jin 《Computers, Materials & Continua》 SCIE EI 2018年第4期165-176,共12页
Dioxin is a highly toxic and caustic substance,which widely existed in the atmosphere,soil and water with tiny particles.Dioxin pollution has become a major problem that concerns the survival of mankind,which must be ... Dioxin is a highly toxic and caustic substance,which widely existed in the atmosphere,soil and water with tiny particles.Dioxin pollution has become a major problem that concerns the survival of mankind,which must be strictly controlled.The bond length,bond angle,energy,dipole moment,orbital energy level distribution of dioxin under the external field are investigated using DFT(density functional theory)on basis set level of B3LYP/6-31G(d,p).The results indicate that with the increase of the electric field,the length of one Carbon-Oxygen bond increases while another Carbon-Oxygen bond decreases.The energy gradually decreases with the electric field,while the change of the dipole moment has an opposite trend.In the infrared spectra,the vibration frequency decreases with the electric field increasing and shows an obvious red shift.Moreover,the ultraviolet-visible absorption spectra under different electric fields are analyzed with TD-DFT(time-dependent density functional theory)method.The wavelength of the strongest absorption peak increases and occurs red shift with the increase of the electric field.All the above results can provide reference for further research on the properties of dioxin under different external electric field. 展开更多
关键词 DIOXIN IR spectrum UV-vis spectrum electric field density functional theory excited states
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Cellular Localization of Gold and Mechanisms of Gold Resistance in <i>Rhodobacter sphaeroides</i>
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作者 Hannah Johnson Ram C. Kafle Madhusudan Choudhary 《Advances in Microbiology》 2017年第8期602-616,共15页
Heavy metal pollution is a worldwide problem with many associated health risks, including bone loss, kidney damage, and several forms of cancer. There is a great need of bioremediation of these toxic metals from the e... Heavy metal pollution is a worldwide problem with many associated health risks, including bone loss, kidney damage, and several forms of cancer. There is a great need of bioremediation of these toxic metals from the environment, as well as implementing a monitoring system to control the spreading pollution. This study focuses on the bioremediation potential of Rhodobacter sphaeroides in the presence of the toxic gold chloride (AuCl3). Growth characteristics of the bacterial cells exposed to a range of toxic gold concentrations were analyzed through the growth kinetics and the colony forming units under aerobic, photosynthetic, and anaerobic growth conditions. The localization of the gold particles within two cellular fractions, cytoplasm and the plasma membrane, are analyzed using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Results of this study demonstrated the photosynthetic growth condition as best suited for the metal tolerance, compared to the aerobic and anaerobic growth conditions. Results also revealed the overall accumulation and localization of gold particles, while not different between the membrane and the cytoplasmic fractions increased at different concentrations of the gold contamination. The results of the localization under photosynthetic growth condition revealed the accumulation reached the highest very quickly, and an overall shift in localization of the gold particles from an equal distribution to an increase within the membrane fraction at the highest concentrations of gold contamination. The localization of the gold particles was validated by Transmission Electron Microscopy (TEM) where the results confirmed the increase in accumulation within the membrane, and photosynthetic membranes, of R. sphaeroides. 展开更多
关键词 RHODOBACTER SPHAEROIDES Heavy Metal BIOREMEDIATION Inductively Coupled Plasma (ICP) Transmission Electron Microscopy (TEM)
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Bacterial Heavy Metal Resistance Genes and Bioremediation Potential
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作者 Hannah Johnson Hyuk Cho Madhusudan Choudhary 《Computational Molecular Bioscience》 2019年第1期1-12,共12页
There is a worldwide distribution of heavy metal pollution that can be managed with a bioremediation approach using microorganisms. Several bacterial species belonging to the Proteobacteria have been shown to tolerate... There is a worldwide distribution of heavy metal pollution that can be managed with a bioremediation approach using microorganisms. Several bacterial species belonging to the Proteobacteria have been shown to tolerate heavy metal stress, including toxic salts of noblemetals. Rhodobacter sphaeroides, a model bacterium has previously been utilized for bioremediation studies. A bioinformatics approach was employed here to identify the distribution of genes associated with heavy metal tolerance among the sequenced bacterial genomes currently available on the NCBI database. The distribution of these genes among different groups of bacteria and the Cluster of Orthologous Groups (COGs) were further characterized. A total of 170,000 heavy metal related genes were identified across all bacterial species, with a majority of the genes found in Proteobacteria (46%) and Terrabacteria (39%). Analysis of COGs revealed that the majority of heavy metal related genes belong to metabolism (COG 3), including ionic transport, amino acid biosynthesis, and energy production. 展开更多
关键词 RHODOBACTER SPHAEROIDES HEAVY Metal Tolerance Genes BIOREMEDIATION
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Small-molecule chemical probes for the potential therapeutic targets in alcoholic liver diseases
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作者 Ashish Dogra Feng Li 《Liver Research》 CSCD 2023年第3期177-188,共12页
Alcoholic liver disease(ALD)encompasses a range of conditions resulting from prolonged and excessive alcohol consumption,causing liver damage such as alcoholic fatty liver,inflammation,fibrosis,and cirrhosis.Alcohol c... Alcoholic liver disease(ALD)encompasses a range of conditions resulting from prolonged and excessive alcohol consumption,causing liver damage such as alcoholic fatty liver,inflammation,fibrosis,and cirrhosis.Alcohol consumption contributes to millions of deaths each year.So far,the effective treatments for ALD are limited.To date,the most effective treatment for ALD is still prevention by avoiding excessive alcohol consumption,and only few specialized medicines are in the market for the treatment of patients suffering from ALD.Small molecules targeting various pathways implicated in ALD pathogenesis can potentially be used for effective therapeutics development.In this review,we provide a concise overview of the latest research findings on potential therapeutic targets,specifically emphasizing small-molecule interventions for the treatment and prevention of ALD. 展开更多
关键词 Alcoholic liver disease(ALD) Signaling pathways PATHOGENESIS Therapeutic target chemical probe Small-molecule probe
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利用激光诱导击穿光谱技术探测大气颗粒物中的Pb元素 被引量:9
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作者 张启航 刘玉柱 +3 位作者 祝若松 金峰 周冯斌 尹文怡 《激光与光电子学进展》 CSCD 北大核心 2018年第12期517-523,共7页
大气颗粒物中的重金属对人体健康具有巨大危害,对其中的重金属元素进行快速检测具有重要意义。利用激光诱导击穿光谱技术对大气颗粒物样品中的重金属元素进行快速分析,结果显示在大气颗粒物样品中含有Na、Al、Si、Cu、Mg、Fe等元素。以C... 大气颗粒物中的重金属对人体健康具有巨大危害,对其中的重金属元素进行快速检测具有重要意义。利用激光诱导击穿光谱技术对大气颗粒物样品中的重金属元素进行快速分析,结果显示在大气颗粒物样品中含有Na、Al、Si、Cu、Mg、Fe等元素。以Ca元素为参考元素,采用内标法对大气颗粒物中的Pb元素进行定量分析,通过拟合得到定标曲线,计算出Pb元素的检出限为34.3×10-6。分析了Pb元素的等离子体温度、电子数密度等相关特性。实验结果验证了LIBS技术用于大气颗粒物中重金属元素定性与定量分析的可行性,为监测大气颗粒物重金属污染提供了实验依据。 展开更多
关键词 光谱学 激光诱导击穿光谱 大气光学 颗粒物 重金属 定量分析
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