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Development and assessment of a multifunctional chitosan-based coating applied on AZ31 magnesium alloy: corrosion resistance and antibacterial performance against Klebsiella Pneumoniae

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Journal of magnesium and Alloys 2021年第6期9卷 2133-2144页

作者： Emmanuel mena-morcillo Lucien Veleva mariana cerda-Zorrilla montserrat Soria-castro Juan c.castro-Alcátara Rosa c.canul-Puc Applied Physics Department Center for Research and Advanced Study(CINVESTAV-IPN)Carr.Ant.a Progreso Km.697310MeridaYucatanMexico marine Resources Department Center for Research and Advanced Study(CINVESTAV-IPN)Carr.Ant.a Progreso Km.697310MeridaYucatanMexico

This work presents a simple method to functionalise the surface of AZ31 magnesium alloy by applying a duplex mgF_(2)/chitosan coating,which improves its corrosion resistance and provides it with some antibacterial ***,the effect of three chitosan solutions with different concentrations on the growth of the bacteria Klebsiella pneumoniae in nutritive medium(TSB)was evaluated by absorbance kinetics experiments,where the chitosan solution at 2%(m/V)was selected for the coating *** coating application,the AZ31 substrate was pretreated with hydrofluoric acid for 48 hours in order to form a mgF_(2)conversion ***,the coating was applied to the pretreated substrate through the dry-casting *** of the alloy in each surface condition(bare,pretreated,and pretreated+coated with chitosan)were exposed to simulated body fluid(SBF)for 21 days at 37°c,with the solution renewed every 24 hours and the wastes *** surfaces were characterised by SEm-EDS,and XPS after the immersion tests,whereas the stored solutions were employed to measure the change in the mg-ions *** impedance spectroscopy and potentiodynamic polarisation were performed in each surface condition to compare their corrosion resistance in *** antibacterial activity of the functionalised surfaces was evaluated by the plate counting method and compared with bare *** results were correlated and demonstrate that the modified surface of AZ31 achieved a higher corrosion resistance when it was exposed to SBF,as well as a reduction of the bacterial growth during in vitro tests.

关键词： AZ31 chitosan coating Simulated body fluid corrosion Antibacterial activity

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从历代文献探究蒙古书面语“元音+■”和“元音+■”的性质及其演变规律

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中国文字研究 2024年第1期 210-218页

作者：斯·劳格劳彻·萨如拉内蒙古大学蒙古学学院内蒙古呼和浩特010021

回鹘式蒙古文或现行蒙古文词中元音之后的■是音节、复合元音还是音节末辅音?学者们持有不同的观点。在蒙古文中,■是多音字形,因此单从蒙古文文献或上述字符自身所包含的信息很难判定其性质。本文以婆罗米文蒙古语文献、八思巴字蒙古... 详细信息

回鹘式蒙古文或现行蒙古文词中元音之后的■是音节、复合元音还是音节末辅音?学者们持有不同的观点。在蒙古文中,■是多音字形,因此单从蒙古文文献或上述字符自身所包含的信息很难判定其性质。本文以婆罗米文蒙古语文献、八思巴字蒙古语文献、托忒文文献等不同时期蒙古语文献为依据,从■所对应的字符序列阐释了其性质和演变规律。我们认为,在古代蒙古语词中元音之后的“■”表示一个单独的音节“yi”,但到中期蒙古语随着“y”的元音属性的逐渐突出,这一书写形式也发生了变化,词中依然是单独的音节,但词末变成了复合元音的组成部分。再到托忒文或现代蒙古文,词中和词末均变成了构成复合元音的元素。

关键词：蒙古书面语 “元音+■”形式 “元音+■”形式音节末辅音复合元音

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SURFAcE SPEcIES ON Re2O7/Al2O3 mETATHESIS cATALYSTS——A FAST ATOm BOmBARDmENT mASS SPEcTROmETRY STUDY

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chinese Journal of chemical Engineering 1988年第1期 98-103页

作者：徐孝定 c.BOELHOUWER J.c.mOL R.H.FOKKENS N.m.m.NIBBERING the Netherlands Laboratory of Organic chemistry University of Amsterdam Amsterdam the Netherlands Laboratory of Organic chemistry University of Amsterdam Amsterdam the Netherlands Department of chemistry Fudan University Shanghai Institute of chemical Technology University of Amsterdam Amsterdam the Netherlands Institute of chemical Technology University of Amsterdam Amsterdam

Various rhenium compounds and activated Re2O7/Al2O33 catalysts were studied by negative ion fastatom bombardment mass spectrometry（FAB-mS）.Analysis of the spectra indicates that on the surfaces ofthe catalysts,in addition to Re2O7,there are surface species characterized by RexO-ypeaks with largenumbers of x and y,which could be precursors of active sites in metathesis.

关键词： Re SURFAcE SPEcIES ON Re2O7/Al2O3 mETATHESIS cATALYSTS A FAST ATOm BOmBARDmENT mASS SPEcTROmETRY STUDY FAST Al

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Sub-stoichiometric functionally graded titania fibres for water-splitting applications

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Journal of Semiconductors 2015年第6期36卷 11-16页

作者： Vaia Adamaki A.Sergejevs c.clarke F.clemens F.marken c.R.Bowen mechanical Engineering Department University of Bath Electronic and Electrical Engineering Department University of Bath High Performance ceramics EMPA Materials Science and Technology chemistry Department University of Bath

The photo-electro-chemical （PEc） splitting of water requires semiconductor materials with a minimum energy gap of 1.23 eV along with conduction and valence bands overlapping the oxidation of H20 and reduction of H＋ respectively. This work overcomes the limitations of stoichiometric titania by manufacturing fine scale fibres that exhibit a compositional gradient of oxygen vacancies across the fibre length. In such a fibre configuration the fibre end that is chemically reduced to a relatively small extent performs as the photoanode and the oxygen vacan- cies enhance the absorption of light. The fibre end that is reduced the most consists of magn61i phases and exhibits metallic electrical conductivity that enhances the electron-hole separation. The structure and composition of the functionally graded fibres, which were manufactured through extrusion, pressureless sintering and carbo-thermal reduction, are studied using XRD and electron microscopy. Electrochemical impedance spectroscopy measure- ments were performed in a three-electrode electrochemical system and showed that the oxygen vacancies in the functionally graded fibres affect the fiat band potential and have increased carrier density. The efficiency of the system was evaluated with PEc measurements that shows higher efficiency for the functionally graded fibres com- pared to homogeneous TiO2 or magn61i phase fibres. The functionally graded and fine scale fibres have the potential to be used as an array of active fibres for water splitting applications.

关键词： titania suboxides water splitting photocurrent

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Amino Acid Sequence of an Excitatory Insect-selective Toxin (BmK IT) From Venom of the Scorpion Buthus martensi Karsch

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Science china chemistry 1994年第1期37卷 42-49页

作者：吉永华 P. mansuelle 徐科 c. Granier c. Kopeyan S. Terakawa H. Rochat Shanghai Institute of Physiology Academia Sinica Shanghai 200031 PRC Laboratoire de Biochemie cNRS URA 1455 INSERm U 172 Faculte de medcecine Secteur Nord BdPierre Dramard 13326 Marseille Cedex 15France

The insect-selective neurotoxin(BmK IT) of scorpion Buthus martensi Karsch was first reduced and S-alkylated, and then digested by TPcK-trypsin and Staphylococcus aureus V-8 Protease. The enzymatic peptides were purified on TLc-plastic sheet and submitted to determine their amino acid compositions and sequences. The sequence of the 70 amino acid residues of BmK IT was established with reference to the primary structure of AaH IT, another excitatory insect-selective toxin from the venom of North African scorpion Androctonus australis Hector. About 75% of the homologous sequence was found in the molecules of BmK IT and AaH IT. It is obvious that the results contribute toward better understanding of the molecular structure characteristics, structure/activity relationship of scorpion insect-selective toxins, and they can serve as the molecular basis for utilizing the toxins as a tool to clarify molecular mechanism involved in channel gating, and to infer the possibility of developing them as new selective bioinsecticides.

关键词： scorpion Buthus martensi Karsch insect-selective neurotoxin amino acid sequence structure/activity relationship.

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Vertical axis wind turbine with omni-directional-guide-vane for urban high-rise buildings

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Journal of central South University 2012年第3期19卷 727-732页

作者： W. T. chong S. c. Poh A. Fazlizan K. c. Pan Department of mechanical Engineering University of Malaya 50603 Kuala Lumpur Malaysia UmPEDAc Level 4 Engineering Tower Faculty of Engineering University of Malaya 50603 Kuala Lumpur Malaysia

A novel shrouded wind-solar hybrid renewable energy and rain water harvester with an omni-directional-guide-vane(ODGV) for urban high-rise application is *** ODGV surrounds the vertical axis wind turbine(VAWT) and enhances the VAWT performance by increasing the on-coming wind speed and guiding it to an optimum flow angle before it interacts with the rotor *** ODGV scaled model was built and tested in the *** experimental results show that the rotational speed of the VAWT increases by about 2 *** show that the installation of the ODGV increases the torque output of a single-bladed VAWT by 206% for tip speed ratio of *** result also reveals that higher positive torque can be achieved when the blade tangential force at all radial positions is *** conclusion,the ODGV improves the power output of a VAWT and this integrated design promotes the installation of wind energy systems in urban areas.

关键词： vertical axis wind turbine green architecture omni-directional-guide-vane wind-solar-rain water harvester urban wind energy generation

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1,2,3-Triazole tethered acetophenones: Synthesis, bioevaluation and molecular docking study

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chinese chemical Letters 2016年第7期27卷 1058-1063页

作者： mubarak H.Shaikh Dnyaneshwar D.Subhedar Vijay m.Khedkar Prakash c.Jha Firoz A.Kalam Khan Jaiprakash N.Sangshetti Bapurao B.Shingate UGc-SAP and DST-FIST Sponsored Department of chemistry Dr. Babasaheb Ambedkar Marathwada University School of Health Sciences University of Kwa Zulu Natal Westville Campus School of chemical Sciences Central University of Gujarat Department of Pharmaceutical chemistry Y. B. Chavan College of Pharmacy Dr. Rafiq Zakaria Campus

A small focused library of eighteen new 1,2,3-triazole tethered acetophenones has been efficiently prepared via click chemistry approach and evaluated for their antifungal and antioxidant *** antifungal activity was evaluated against five human pathogenic fungal strains：candida albicans,Fusarium oxysporum,Aspergillus flavus,Aspergillus niger,and cryptococcus *** the synthesized compounds,9c,9i,and 9p found to be more potent antifungal agents that the reference *** 1,2,3-triazole based derivatives were also evaluated for antioxidant activity,and compound 9h was found to be the most potent antioxidant as compared to the standard ***,molecular docking study of the newly synthesized compounds was performed and results showed good binding mode in the active site of fungal *** enzyme P450 cytochrome ***,the synthesized compounds were also analyzed for ADmE properties and showed potential as good oral drug candidates.

关键词： 1,2,3-Triazole Antifungal Antioxidant molecular docking ADmE prediction

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Bright, periodic, compacton and bell-shape soliton solutions of the extended QZK and (3+1)-dimensional ZK equations

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communications in Theoretical Physics 2021年第10期73卷 23-35页

作者： m Ali Akbar md Abdul Kayum m S Osman Department of Applied mathematics University of RajshahiBangladesh Department of computer Science&Engineering North Bengal International UniversityRajshahiBangladesh Department of mathematics Faculty of ScienceCairo UniversityGiza 12613Egypt

The(3+1)-dimensional Zakharov–Kuznetsov(ZK) and the new extended quantum ZK equations are functional to decipher the dense quantum plasma, ion-acoustic waves, electron thermal energy,ion plasma, quantum acoustic waves, and quantum Langmuir waves. The enhanced modified simple equation(EmSE) method is a substantial approach to determine competent solutions and in this article, we have constructed standard, illustrative, rich structured and further comprehensive soliton solutions via this method. The solutions are ascertained as the integration of exponential, hyperbolic,trigonometric and rational functions and formulate the bright solitons, periodic, compacton, bellshape, parabolic shape, singular periodic, plane shape and some new type of solitons. It is worth noting that the wave profile varies as the physical and subsidiary parameters change. The standard and advanced soliton solutions may be useful to assist in describing the physical phenomena previously mentioned. To open out the inward structure of the tangible incidents, we have portrayed the three-dimensional, contour plot, and two-dimensional graphs for different parametric values. The attained results demonstrate the EmSE technique for extracting soliton solutions to nonlinear evolution equations is efficient, compatible and reliable in nonlinear science and engineering.

关键词： (3+1)-dimensional ZK the extended QZK equation enhanced modified simple equation method soliton solutions NLEEs

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characterization of atmospheric aerosol (Pm10 and Pm2.5) from a medium sized city in S?o Paulo state,Brazil

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Journal of Environmental Sciences 2020年第3期32卷 238-251页

作者： Bruno T.Franzin Filipe c.Guizellini Diego V.de Babos Ossamu Hojo Ieda Ap.Pastre mary R.R.marchi Fernando L.Fertonani cristina m.R.R.Oliveira Sao Paulo State University(Unesp) Chemistry InstituteAnalytical Chemistry DepartmentAraraquaraSP14800-060Brazil Federal University of Sao carlos-UFScAr Chemistry DepartmentSao CarlosSP13565-905Brazil chemistry and Environmental Sciences Department BiosciencesLanguages and Exact Sciences InstituteIbilceSaoPaulo State University(Unesp)Sao Jose do Rio PretoSP15054-000Brazil centro de Quimica Estrutural-Faculdade de ciencias da Universidade de Lisboa Edif.C8Campo Grande1749-016 LisboaPortugal

Air pollution causes deleterious effects on human health with aerosols being among the most polluting *** objective of this work is the characterization of the Pm2.5 and Pm10 aerosol mass in the *** methods of analysis include WD-XRF and *** were correlated with meteorological information and air mass trajectories(model HYSPLIT)by multivariate analysis.A morphological structural analysis was also carried out to identify the probable sources of atmospheric aerosols in the city of Sao Jose do Rio Preto,*** mean mass concentration values obtained were 24.54 μg/m^3 for Pm10,above the WHO annual standard value of 20 μg/m^3 and 10.88 μg/m^3 for Pm2.5 whose WHO recommended limit is10 μg/m^***-XRF analysis of the samples revealed Si and Al as major components of the coarse *** the fine fraction,the major elements were Al and *** SEm-FEG characterization allowed identifying the morphology of the particles in agglomerates,ellipsoids and filaments in the Pm10,besides spherical in the *** analysis by EDS corroborated WD-XRF results,identifying the crustal elements,aluminosilicates and elements of anthropogenic origin in the coarse *** the fine fraction crustal elements were also identified;aluminosilicates,black carbon and spherical particles(c and O) originating from combustion processes were *** use of multivariate analysis to correlate air mass trajectories with the results of the morpho-structural characterization of the particulate matter allowed confirmation of the complex composition of the particles resulting from the combination of both local and long-distance sources.

关键词： Urban aerosol Pm10 Pm2.5 WD-XRF SEm-EDS

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Speciation of Dissolved Trace Nickel in Environmental Waters by On-Line Sonodigestion-Flow Injection Solid Phase Extraction coupled to Flame Atomic Absorption Spectrometry

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American Journal of Analytical chemistry 2011年第2期2卷 116-125页

作者： m. c. Yebra-Biurrun J. m. castro-Romero 不详

A simple on-line sonodigestion system was successfully used for breakdown organic nickel complexes in environmental waters acidified with diluted nitric acid prior to flow injection total dissolved nickel preconcentration in a microcolumn containing a chelating resin (chelite che with iminodiacetic acid groups) and determination by flame atomic absorption spectrometry. For the determination of the dissolved labile nickel fraction, microcolumns packed with the chelating resin were loaded in-situ with the sample without sample pH modification, and once in the laboratory were inserted in the flow injection device where nickel elution-detection was carried out. The performance of the chelating resin was investigated in order to elucidate its behavior in the presence of dissolved nickel species. The results obtained reveal that the resin, at the experimental employed conditions, retained only dissolved free nickel ions and nickel bound to weak complexes (labile fraction). The figures of merit for determinations in both nickel fractions are given and the obtained values are discussed. The speciation scheme is applied to the analysis of nickel in river and seawater samples collected in Galicia (Northwest, Spain). The results of fractionation showed that Ni are mainly in the dissolved labile fraction in river water, while in seawater samples analyzed was mainly present in the organic fraction.

关键词： Sonodigestion Preconcentration Flow Injection Nickel Speciation Flame Atomic Absorption Spectrometry Environmental Water

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