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《分子催化》2018,(1):26-26
《分子催化》是由中国科学院兰州化学物理研究所主办、中国科学院主管、科学出版社出版的向国内外公开发行的学术性刊物.主要报道有关分子催化方面最新进展与研究成果.辟有学术论文、研究简报、研究快报及综合述评等栏目.内容侧重于配位催化、酶催化、光助催化、催化过程中的立体化学问题、催化反应机理与动力学、催化剂表面态的研究及量子化学在催化学科中的应用等.工业催化过程中的均相催化剂、固载化学的均相催化剂、固载化的酶催化剂等活化、失活和再生;用于新催化过程的催化剂的优选与表征等方面的内容,本刊亦有报道.读者对象主要是科研单位及工矿企业中从事催化工作的科技人员、研究生、高等院校化学系和化工系的师生. 相似文献
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催化表面物理化学主要是研究多相催化反应体系催化剂的表面结构.催化性.能关系和催化反应机理从而获得原子分子水平上的理解,为催化剂的改进和设计提供指导.真实催化剂的结构复杂性和不均一性使得无法明确关联其结构和催化性能.,因此构筑结构均一的模型催化剂体系是进行催化表面物理化学研究的常用方法.本文介绍了本研究组在催化表面物理化学模型体系研究中的研究理念,综述了近5年来取得的研究进展.我们将模型催化剂的概念从传统的基二二单晶/单晶薄膜的模型催化剂拓展到基于纳米晶的模型催化剂,由简单到复杂,在不同层次构筑模型催化剂,开展催化表面物理化学研究.这种研究理念有可能实现在原子分子水平理解真实催化反应条件下的催化剂结构..催化性能关系和催化反应机理. 相似文献
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报道了硫酸钴-乙酸在室温、无溶剂条件下催化醇和酚的四氢吡喃化反应。硫酸钴-乙酸作为协同催化体系,二者缺一不可。与传统催化剂相比,新催化体系的催化活性最好.反应结束后,硫酸钴经简单相分离可回收,重复使用多次催化活性无明显下降。提出了可能的催化反应机理. 相似文献
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The densities of methanol, ethanol, 1-propanol, 1-butanol and 1-hexanol were measured in aqueous solutions of sodium dodecylsulfate at 25°C. The partial molar volumes of the alcohols at infinite dilution in the aqueous surfactants solutions were calculated and discussed using a mass-action model for the alcohol distribution between the aqueous and the micellar phase. The partial molar volumes of the alcohols in the aqueous and in the micellar phases, and the ratios between the binding constant and the aggregation number, were calculated. The partial molar volume for all the alcohols in micellar phase is 10 cm3-mol–1 smaller than that in octane. This can be related to the strong hydrophilic interaction between the head groups of the alcohol and the micellized surfactant. From the extrapolated values of the distribution constant and the partial molar volumes in the aqueous and micellar phases, the standard partial molar volume of heptanol in micellar solutions was found to decrease with increasing surfactant concentration. The standard free energy of transfer of alcohols from water to micelles was rationalized in terms of hydrophilic and hydrophobic contributions. A model is proposed in which the empty space around each solute is assumed to be the same in the gas and liquid phases, and is used to explain the behavior of micelles in the presence of amphiphilic solutes. 相似文献
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《中国化学快报》2020,31(6):1462-1473
Graphene is a two-dimensional nanomaterial with huge surface area,high carrier mobility and high mechanical strength.Because of its great potential in nanotechnology and environmental protection,it has attracted much attention in environmental and energy fields since its discovery in 2004.Although graphene is a star material,many reviews have introduced its use in terms of energy,the research progress in the field of environment,especially water pollution control,has been rarely reported.Here,we review exhaustively the research progress of graphene-based materials in environmental pollution remediation in the past ten years.Firstly,the advantages and classification of graphene were introduced.Secondly,the research progress and main achievements of graphene and its composites in the fields of photocatalytic degradation,pollutant adsorption and water treatment were emphatically described,and the mechanism of action in the above fields was summarized.Finally,we discuss the problems existing in the preparation and summarize the application of graphene in the environment. 相似文献
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Xiaofang Long Niao Wang Qingmei Song Ye Wang Lingzhu Chen Deyu Hu Yuping Zhang 《Biomedical chromatography : BMC》2020,34(3):e4745
Using LC–MS/MS, a rapid and sensitive method for the simultaneous determination of pyraclostrobin and azoxystrobin residues in banana matrices (leaf and whole banana) and soil was established. The samples were extracted using acetonitrile and purified through C18 dispersive solid-phase extraction. The average recovery of the analytes in various matrices was in the range of 77.3%–103.9% with an RSD range of 0.9%–9.5%. The initial deposition amounts of pyraclostrobin and azoxystrobin at 2 h in the banana leaves of the mineral oil group were 1.43 and 1.31 times in Guangxi, and 2.10 and 1.81 times in Hainan for the water group, whereas those in the soil of the water group were 3.45 and 3.03 times in Guangxi, and 2.14 and 3.48 times in Hainan for the mineral oil group. The half-lives in the leaves and soil of the mineral oil group were not remarkably different from those of the water group. The terminal residue of the analytes on the whole banana was <0.02 mg/kg at 14 days after application from the two sites. The results of this work may indicate and promote the safety of using pyraclostrobin and azoxystrobin in banana production, especially with mineral oil spray adjuvants. 相似文献
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大气臭氧化学研究进展 总被引:5,自引:0,他引:5
臭氧是大气化学中的核心物种。在平流层中,臭氧层可以吸收对生物有害的紫外辐射,对地球生命起保护伞作用。在对流层大气中,适量臭氧对清洁大气是有益的。但是,由于对流层中臭氧前体物排放量的增加,特别是在大城市,产生的高浓度臭氧会对大气环境造成严重污染,对人类、动植物和生态环境具有极大危害。臭氧的研究一般结合外场观测、实验室烟雾箱模拟和计算机数值模拟进行。深入开展大气臭氧化学研究,不仅有助于全面深入理解大气氧化过程以及全面掌握区域乃至全球大气自净能力,而且能为对流层污染控制提供科学依据和方案。本文总结了近年来有关臭氧化学的研究进展,论述了臭氧问题与人类当前面临的一些主要环境问题间的相互关系;重点综述了近年来有关南极臭氧空洞、中纬度地区臭氧低值和北极地区臭氧的损耗机理及其发展趋势;综述了臭氧与大气光化学和气溶胶间的耦合关系,并结合我国实际情况,提出了大气臭氧化学尚待深入开展研究的一些重要科学问题。 相似文献
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中国煤中铍的分布赋存特征研究 总被引:2,自引:3,他引:2
根据对中国不同矿区1018个煤层煤样和生产煤样铍含量数据的统计结果,分析了中国不同成煤时代、不同聚煤区煤中铍的分布特征。同时,根据对10个不同煤田煤样的实验室浮沉试验、煤岩分析等试验研究,运用Solari方法,计算了煤中各组分中铍的理论含量,讨论了中国煤中铍的赋存特征,尤其是铍在各种煤岩组分中的分布。研究表明,铍在煤中富集程度较高,但相对于世界煤中平均水平来说,中国煤中铍含量总体水平较低。煤中铍主要赋存于惰质组及伊利石粘土矿物中,在镜质组及其它矿物中含量较低。同时,中国大多数煤中铍的有机亲和性指数较高,不利于选煤过程中铍的脱除。 相似文献
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Limitations of current proteomics technologies 总被引:9,自引:0,他引:9
Application of proteomics technologies in the investigation of biological systems creates new possibilities in the elucidation of biopathomechanisms and the discovery of novel drug targets and early disease markers. A proteomic analysis involves protein separation and protein identification as well as characterization of the post-translational modifications. Proteomics has been applied in the investigation of various disorders, like neurological diseases, and the application has resulted in the detection of a large number of differences in the levels and the modifications of proteins between healthy and diseased states. However, the current proteomics technologies are still under development and show certain limitations. In this article, we discuss the major drawbacks and pitfalls of proteomics we have observed in our laboratory and in particular during the application of proteomics technologies in the investigation of the brain. 相似文献
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环境中锑的分布、存在形态及毒性和生物有效性 总被引:42,自引:0,他引:42
由于自然过程及人类活动的影响,锑及其化合物在环境中普遍存在,环境中锑的污染也日益严重.近年来,国外对锑污染的研究日益重视.锑不是植物必需的,但能够被植物根系吸收.已有证据表明锑对生物及人体产生毒性.本文主要对环境中锑的分布和存在形态,及对动物和人体的毒性和对生物有效性研究进展进行评述。 相似文献
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Electrodeposited layers of nickel show different growth characteristics depending on the composition of the electrolyte, namely
the type of the anion, the presence or the absence of boric acid and the pH. These process parameters are examined in the
present work in order to elucidate their influence upon the growth texture and the related surface morphology of the electrodeposits.
The relationship between process and structure is investigated by studying the transient electrochemical behavior during deposition,
in order to discriminate between different interface conditions corresponding to different growth modes. The observed preferred
orientations can be in this way linked to different reactive species, which are assumed to be present at the surface, and
to their stability. The correlation between kinetics and structure in nickel electrodeposition reported in the present work
and the similar correlation found in cobalt electrodeposition suggest a rationalization of the growth modes of ECD inert metals,
based on the correspondence between the transient Tafel parameter and the growth texture observed in defined conditions.
Published in Russian in Elektrokhimiya, 2008, Vol. 44, No. 6, pp. 771–783.
The text was submitted by the authors in English. 相似文献
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Skupińska Jadwiga Karpińska Monika Ołówek Maria Kasprzycka-Guttman Teresa 《Central European Journal of Chemistry》2005,3(1):28-39
The PdCl2/Fe/I2/Py catalytic system (Py-pyridine), reported to be highly active in the reaction of nitrobenzene carbonylation to ethyl phenylcarbamate
was studied. The present paper describes the role of catalyst components and its effect on the activity and selectivity of
the catalyst. The increase in the amount of PdCl2 in the system while retaining a constant level of the other catalyst components, results in the increase of both carbamate
and aniline yields. The increase in the amount of iron while retaining the other components constant, initially causes an
increase in the carbamate yield; however, at Fe: Pd ratios higher than 36, the carbamate yield remains constant. The change
in the amount of iron has no effect on the amount of aniline formed in the system. An increase in the amount of iodine in
the system while retaining the other components constant, results in a decrease in carbamate yield and a considerable increase
in the aniline yield of the reaction products. 相似文献
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The accelerated growth of aquaculture has resulted in a series of harmful effects to human health. The widespread and unrestricted use of antibiotics in this industry, to prevent bacterial infections, leads to remaining amounts in the aquatic environment. This has resulted in the emergence of antibiotic-resistant bacteria in aquaculture environments, in the increase in antibiotic resistance in fish pathogens as well as in the transfer of these resistance determinants to human pathogens. Moreover, the use of large amounts of antibiotics may lead to the presence of residual antibiotics in fish tissue and fish products. Fluoroquinolones, tetracyclines, penicillins, sulphonamides and other antibiotics, exhibiting activity against both Gram-positive and Gram-negative bacteria, are widely used for the treatment and prevention of diseases in fish. An extended and comprehensive review on the recent analytical methodologies concerning antibiotic residues in fish reported in the literature is provided in the present article. Emphasis is given on sample preparation regarding isolation and purification, chromatographic conditions and method validation according to legislation. Results of published assays are comparatively presented and criticised. 相似文献