检索结果-南通市图书馆

Tyrosinase Biosensor Used for the determination of Catechin derivatives in Tea: Correlation with HPLC/dAd Method

Food and Nutrition Sciences 2013年第1期4卷 108-118页

作者： Saloua Nadifiyine Carole Calas-Blanchard Aziz Amine Jean-Louis Marty Institut de Modélisation et d’Analyse en Géo-Environnement et Santé Univ. Perpignan Via Domitia Perpignan France Institut de Modélisation et d’Analyse en Géo-Environnement et Santé Univ. Perpignan Via Domitia Perpignan France&Laboratoire d’Analyses Chimiques et Biocapteurs Faculté des Sciences et Techniques Université Hassan II Mohammedia Morocco. laboratoire d’analyses chimiques et biocapteurs Faculté des Sciences et Techniques Université Hassan II Mohammedia Morocco.

Tea, one of the most popular consumed worldwide beverages, is known to be rich in polyphenols, more particularly in catechins. An amperometric biosensor based on tyrosinase was developed in order to monitor the phenolic content in black and green teas. The enzyme was immobilised by coreticulation with glutaraldehyde on carbon screen-printed electrodes (CSPE). Initially, the performances of the biosensor were evaluated referring to catechol as a model substrate. This analytical tool exhibits a high sensitivity (217 nA/μM), low limit of detection (LOd) = 0.03 μM, good intra-electrode and inter-electrode reproducibilities with RSd lower than 3% (n = 5 injections) and RSd = 8.14% (n = 12 sensors) respectively. The storage stability was also studied;the biosensor retained successively 85% and 70% of its initial response after 34 and 53 days. Subsequently, several catechin derivatives frequently found in teas were tested and classified relatively to their sensitivities. For tea samples, the results obtained with the biosensors were compared to high performance liquid chromatography (HPLC) analysis. A good correlation between the two methods was obtained. The calculated recovery was between 90% and 96%, proving that the proposed tyrosinase biosensor can be an alternative analytical tool for global determination of catechin derivatives in tea.

关键词： Tea Polyphenol Catechin Tyrosinase Amperometric Biosensor HPLC

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Preface to the special issue on Mesoscopic Solar Cells

引用

Frontiers of Optoelectronics 2016年第1期9卷 1-2页

作者： Michael Graitzel laboratoire de Photoniques et Interfaces Institut des Sciences et Ingenierie Chimiques Ecole Polytechnique Federale de Lausanne Lausanne Switzerland

Energy crisis and environment pollution are the main challenges of human beings in the 21th century. developing solar cells with high efficiency and stability at low production cost is an effective way to achieve ＂price parity＂ with fossil-fuel-based grid power and large-scale use of solar energy. Since the breakthrough of dye-sensitized solar cells （dSSCs） in 1991, mesoscopic solar cells have been developing fast. Especially in the past three years, the power conversion efficiency （PCE） of perovskite solar cells based on mesoporous structure increased at an amazing rate.

关键词：

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Rh/ZnO-Al_2O_3催化剂用于巴豆醛选择性加氢(英文)

引用

催化学报 2011年第7期32卷 1185-1190页

作者： Mouna AOUN Aicha BENAMAR Mohamed CHATER Centre de Recherche Scientifique et Technique en analyses Physico-chimiques(C.R.A.P.C) laboratoire d'etude Physico-Chimique des Matériaux et Application à l'Environnement Faculté de ChimieUniversité des Sciences et de la Technologie

Gas phase hydrogenation of crotonaldehyde was performed over 1 wt% Rh/ZnO-Al2O3 catalysts with various Zn/Rh atomic ratios. Monometallic Rh/Al2O3 was also prepared for comparison. The samples were prepared by the successive impregnation of Al2O3 with chlo-ride precursors of zinc and rhodium. The solids have been characterized by H2 chemisorption,temperature-programmed reduction,scanning electron microscopy,and cyclohexane dehydrogenation. Their catalytic behaviour in the gas phase crotonaldehyde hydrogenation reaction after reduction treatment in flowing hydrogen at 723 K was investigated. The relationship between catalytic activity,selectivity for crotyl alcohol,and physicochemical properties of the catalysts was examined. Results obtained showed that the presence of Zn clearly promotes the hydrogenation of the carbonyl bond. The catalyst with Zn/Rh atomic ratio of 5 displayed good catalytic stability and the highest selectivity for crotyl alcohol(70%) along with alloy formation.

关键词： rhodium-based catalyst crotonaldehyde hydrogenation zinc oxide selectivity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

donor design and modification strategies of metal-free sensitizers for highly-efficient n-type dye-sensitized solar cells

引用

Frontiers of Optoelectronics 2016年第1期9卷 3-37页

作者： Xiaoyu ZHANG Michael Graitzel Jianli HUA Key Laboratory for Advanced Materials and Institute of Fine Chemicals East China University of Science and Technology Shanghai 200237 China laboratoire de Photoniques et Interfaces Institut des Sciences et Ingenierie Chimiques Ecole Polytechnique Federale de Lausanne Lausanne Switzerland

dye-sensitized solar cells （dSSCs） cannot be developed without the research on sensitizers. As the key of light harvesting and electron generation, thousands of sensitizers have been designed for the application in dSSC devices. Among them, organic sensitizers have drawn a lot of attention because of the flexible molecular design, easy synthesis and good photovoltaic performance. Recently, new record photovoltaic conversion efficiencies of 11.5% for dSSCs with iodide electrolyte and 14.3% for dSSCs with cobalt electrolyte and co-sensitization have been achieved with organic sensitizers. Here we focus on the donor design and modification of organic sensitizers. Several useful strategies and corresponding typical examples are presented.

关键词： donors organic sensitizers dye-sensitizedsolar cells (dSSCs)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Production of liquid bio-fuel from catalytic de-oxygenation:Pyrolysis of beech wood and flax shives

引用

燃料化学学报 2019年第2期47卷 153-166页

作者： Chetna Mohabeer Luis Reyes Lokmane Abdelouahed Stéphane Marcotte Jean-Christophe Buvat Lucette Tidahy Edmond Abi-Aad Bechara Taouk Normandie Univ INSA Rouen NormandieUNIROUENLaboratoire de Sécurité des Procédés Chimiques Normandie Univ INSA Rouen NormandieUNIROUEN Université du Littoral Cte d'Opale Unité de Chimie Environnementale et Interactions sur le Vivant

This study presents a detailed analysis of the catalytic de-oxygenation of the liquid and gaseous pyrolytic products of two biomasses (beech wood and flax shives) using different catalysts (commercial HZSM-5 and H-Y,and lab-synthesised Fe-HZSM-5,Fe-H-Y,Pt/Al2O3 and CoMo/Al2O3). The experiments were all conducted in a semi-batch reactor under the same operating conditions for all feed materials. Bet specific surface area,BJH pore size distribution and FT-IR technologies have been used to characterise the catalysts,while gas chromatography-mass spectrometry (GC-MS),flame ionisation detection (GC-FId) and thermal conductivity detection (GC-TCd) were used to examine the liquid and gaseous pyrolytic products. It was firstly seen that at higher catalyst-to-biomass ratios of 4∶1,de-oxygenation efficiency did not experience any further significant improvement. FeHZSM-5 was deemed to be the most efficient of the catalysts utilised as it helped reach the lowest oxygen contents in the bio-oils samples and the second best was HZSM-5. It was also found that HZSM-5 and H-Y tended to privilege the decarbonylation route(production of CO),whilst their iron-modified counterparts favoured the decarboxylation one (production of CO2) for both biomasses studied. It was then seen that the major bio-oil components (carboxylic acids) underwent almost complete conversion under catalytic treatment to produce mostly unoxygenated aromatic compounds,phenols and gases like CO and CO2. Finally,phenols were seen to be the family most significantly formed from the actions of all catalysts.

关键词： pyrolysis biomass catalytic treatment de-oxygenation bio-oil upgrading

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Polypeptide Brushes Grown via Surface-initiated Ring-opening Polymerization of α-Amino Acid N-Carboxyanhydrides

引用

Chinese Journal of Polymer Science 2015年第7期33卷 931-931,932-946页

作者： Yong Shen 李志波 Harm-Anton Klok Laboratory of Polymer Physics and Chemistry Institute of Chemistry Chinese Academy of Sciences School of Polymer Science and Engineering Qingdao University of Science and Technology cole Polytechnique Fédérale de Lausanne (EPFL) Institut des Matériaux and Institut des Sciences et Ingénierie Chimiques Laboratoire des Polymères Batiment MXD Station 12 CH-1015 Lausanne Switzerland

Polypeptide brushes are attractive platforms to generate functional and responsive interfaces that are of potential interest due to their possible biodegradability, biocompatibility and tunable secondary structures. Surface-initiated ringopening polymerization（SI-ROP） of α-amino acid N-carboxyanhydrides represents a powerful and versatile strategy to generate polypeptide brushes. This review is an attempt to capture the state-of-the-art in this field and highlights the latest developments in several selected areas. In addition to presenting an overview of the synthetic methods that have been used to generate polypeptide brushes via SI-ROP, this article will discuss the preparation of patterned polypeptide brushes, the conformational properties of surface-tethered polypeptides, ways to control chain orientation at surfaces as well as properties and applications of these thin polymer films.

关键词： Polypeptide brushes Surface α-Amino acid N-carboxyanhydrides Ring-opening polymerization Secondary structure

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Enantioselective Aldol Reactions and Michael Additions Using Proline derivatives as Organocatalysts

引用

International Journal of Organic Chemistry 2014年第1期4卷 55-67页

作者： Mathieu Wagner Yohan Contie Clotilde Ferroud Gilbert Revial Conservatoire National des Arts et Métiers Laboratoire de Transformations Chimiques et Pharmaceutiques Paris France

Six compounds including five proline derivatives have been prepared and tested as chiral organocatalysts for enantioselective aldol reactions and Michael additions. The enantiomeric excesses, which are highly dependen... 详细信息

关键词： Aldol Reactions Michael Additions Enantioselective Organocatalysts Proline derivatives

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Preparation of solar-enhanced AlZnO@carbon nano-substrates for remediation of textile wastewaters

引用

Journal of Environmental Sciences 2020年第6期32卷 52-68页

作者： Esraa M.El-Fawal Sherif A.Younis Yasser M.Moustafa Philippe Serp Central Laboratories Analysis and Evaluation DepartmentEgyptian Petroleum Research InstituteNasr CityCairo 11727Egypt laboratoire de Chimie de Coordination(LCC) Unite Propre de Recherche(UPR)Du Centre National de La Recherche Scientifique(CNRS)8241Composante de L’Ecole Nationale D’Ingenieurs en Arts Chimiques et Technologiques(ENSIACET)Universite de ToulouseUniversite Paul Sabatier(UPS)Institut National Polytechnique(INP)-LCC4 Allee Emile Monso31030Toulouse Cedex 4France

Photoactive aluminum doped ZnO(AlZnO)was synthesized by sol-gel *** that,AlZnO photocatalyst was deposited on five carbon-based materials(CBMs)using ultrasonic route followed by solid-state mixing using ball *** CBMs used were poly aniline(PANI),carbon nitride(CN),carbon nanotubes(CNT),graphene(G),and carbon nanofibers(CNF).The crystal phases,elemental compositions,morphological,and optical properties of the AlZnO@CBMs composites were *** results revealed that two of AlZnO@CBMs composites exhibited superior bleaching efficiency(100%removal)and photocatalytic stability(three cycles)for 50μmol/L Methylene Blue(MB)contaminated water after 60 min irradiation in visible light at pH 6.5,0.7%H2O2,and 5 g/L inorganic *** optimum conditions,AlZnO@CBMs nanocomposites were employed for the treatment of mixed dyestuffs composed of MB,Methyl Orange(MO),Astrazone Blue FRR(BB 69),and Rhodamine B(RhB)dyes under dark,ultraviolet,visible,and direct *** mixed dyestuffs,the AlZnO@G achieved the highest dye sorption capacity(60.91μmol dye stuffs/g)with kinetic rate 8.22×10^-3 min^-1 in 90 min via multi-layer physisorption(Freundlich isotherm)on graphene *** additions,AlZnO@CN offered the highest photo-kinetic rate(Kphoto)of^54.1×10^-3 min^-1(93.8%after 60 min)under direct ***,the selective radical trapping experiment confirmed that the holes and oxidative superoxide radicals are crucial on dyes photodegradation *** to their superior performance,AlZnO@G and AlZnO@CN nanocomposites can offer an effective in-situ solar-assisted adsorption/photocatalytic remediation of textile wastewater effluents.

关键词： Carbon nanomaterials AlZnO photocatalyst Hybrid adsorption/photo-catalysis Kinetic and isotherm modeling Textile wastewater remediation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A hybrid PSO-SVM-based model for determination of oil recovery factor in the low-permeability reservoir

引用

Petroleum 2018年第1期4卷 43-49页

作者： Bing Han Xiaoqiang Bian State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu 610500China Ecole Nationale Superieure des Industries chimiques Universite de LorraineLaboratoire Reactions et Genie des Procedese UPR 33491 rue GrandvilleBP 20451Nancy Cedex 9France

Oil recovery factor is one of the most important parameters in the development process of oil reservoir,especially in the low-permeability *** general,the determination of recovery factor can be obtained either experimentally or *** method is often timeconsuming and expensive,while numerical method has been always confined to narrow range of application or relatively large ***,an intelligent method has been proven as an efficient tool to model the complex and nonlinear *** this work,an intelligent model based on support vector machine in combination with the particle swarm optimization(PSO-SVM)technique was established to predict oil recovery factor in the low-permeability *** variables of the proposed PSO-SVM model with the aid of a grey correlation analysis method are permeability,well spacing density,production-injection well ratio,porosity,effective thickness,crude oil viscosity and output parameter is oil recovery factor of low-permeability *** accuracy and reliability of the proposed model were evaluated through 34 data sets collected in the open literature and compared with PSO-BP neural network,empirical method from Oil and Gas *** results indicated that the PSO-SVM model gives the best results with average absolute relative deviation(AARd)of 3.79%,while AARds for the PSO-BP neural network and empirical method are 9.18%and 10.0%,***,outlier detection was used on the basis of whole data sets to definite the valid domains of PSO-SVM and PSO-BP models by detecting the probable doubtful recovery factor data in the low-permeability reservoir.

关键词： PSO-SVM Recovery factor Low permeability Reservoir Outlier detection

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

机械力辅助高分子刷的去接枝效应及机理分析

机械力辅助高分子刷的去接枝效应及机理分析

引用

中国化学会2017全国高分子学术论文报告会

作者：王健 Harm-anton Klok Institut des Mat?riaux et Institut des Sciences et Ing?nierie chimiques Laboratoire des Polym?resE?cole Polytechnique F?d?rale de Lausanne(EPFL)Ba?timent MXD

高分子刷基于它的功能多样性及可控性已经成为科学研究中非常重要的一种高分子涂层,曾几何时,大多数研究者都认为它是一种极其稳定的体系,然而随着近些年研究的深入以及2008年第一篇针对高分子刷在界面去接枝现象的报道,人们开始怀疑从... 详细信息

高分子刷基于它的功能多样性及可控性已经成为科学研究中非常重要的一种高分子涂层,曾几何时,大多数研究者都认为它是一种极其稳定的体系,然而随着近些年研究的深入以及2008年第一篇针对高分子刷在界面去接枝现象的报道,人们开始怀疑从前假设的稳定性。从那以后针对亲水性高分子刷在水溶液中去接枝现象的报道也越来越多,一些研究者证明了这种现象是由高分子刷与其基底连接的化学键断裂导致的,这是一种溶胀引发的机械力催化的水解反应。然而迄今为止,人们对于核心的结构性参数如何影响这一过程仍然缺乏认知,而且研究的范围始终局限在亲水高分子之中。因此在我们的研究中,我们通过原子转移自由基聚合制备了一系列亲水高分子刷,深入研究了诸如引发剂结构,高分子刷的分子量以及界面曲率对去接枝过程的影响,并且准确判断出断裂点发生的位置;我们还进一步制备了疏水性高分子刷,研究并证明了这种去接枝现象在非水性溶剂中也会发生。

关键词：机械力化学高分子刷界面涂层

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：