检索结果-南通市图书馆

Freestanding reduced graphene oxide/sodium vanadate composite films for flexible aqueous zinc-ion batteries

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2019年第5期62卷 609-615页

作者： Fang wan Xinyu wang Songshan Bi Zhiqiang Niu Jun Chen Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) College of ChemistryNankai University Institute of Materials and Technology Dalian Maritime University

With the booming development of portable and wearable electronic devices, flexible energy storage devices have attracted great attention. Among various energy storage devices, aqueous zinc ion batteries(ZIBs) are one of the promising candidates due to their low cost, good safety, high energy and power densities. however, the conventional cathodes of aqueous ZIBs were often prepared by mixing active materials with binders and conductive additives and then coating them onto current collectors. The resultant cathodes often suffer from unsatisfied flexibility. herein, we fabricated freestanding reduced graphene oxide/NaV_3O_8·1.5h_2O(RGO/NVO) composite films with interlinked multilayered architecture by a vacuum filtrating process. Such composite films exhibit excellent mechanical property and high electronic conductivity. Owing to unique architecture, they display a high capacity of 410 mA h g^(-1) and excellent cycling performance up to 2000 cycles with a high capacity retention of 94%. Moreover, RGO/NVO composite films can directly serve as the cathodes of flexible aqueous ZIBs. As a proof of concept,flexible ZIBs were assembled based on the composite films. Impressively, they exhibit stable performance at different bending states, demonstrating great potential application in flexible energy storage devices.

关键词： zinc-ion battery graphene NaV3O8·1.5h2O composite film flexibility

The origin of the site preference of h adsorption on Pd(100)

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2015年第1期58卷 156-161页

作者： Lingyun Zhou Yun Zhao Zhening Chen Gang Fu huilin wan State Key Laboratory for Physical Chemistry of Solid Surfaces Collaborative Innovation Center of Chemistry for Energy Materials Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University

Spin-polarized density functional theory （DPT） calculations are carried out to determine the site preference of h adsorption on Pd（100） surface and subsurface, We carefully scrutinize the energy difference between different patterns at θ=0.50 ML and confirm the LEED observation that surface adsorption can form c（2×2） ordering structure. On the contrary, we disclose that p（2×1） structure become more favorable than c（2×2） for subsurface adsorption. These site preferences are rationalized via an analysis of the layer and orbital resolved density of states. Furthermore, we propose that the interstitial charge as a key factor determining the preferred h adsorbed site.

关键词： h adsorption subsurface adsorption site preference Pd(100) DFT

Density Functional Theory Study on Interaction between Catechin and Thymine

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2012年第6期25卷 642-648,I0003页

作者： wan-fei Cai Yan Zheng Lai-cai Li An-min Tian Departement of Chemistry and Material Science Sichuan Normal University Chengdu 510065China Departement of Chemistry Sichuan University Chengdu 510054 China

The interacting patterns and mechanism of the catechin and thymine have been investigated with the density functional theory Becke＇s three-parameter nonlocal exchange functional and the Lee, Yang, and Parr nonlocal correlation functional （B3LYP） method by 6-31＋G＊ basis set. Thirteen stable structures for the catechin-thymine complexes have been found which form two hydrogen bonds at least. The vibrational frequencies are also studied at the same level to analyze these complexes. The results indicated that catechin interacted with thynfine by three different hydrogen bonds as N-h…O, C-h…O, O-h…O and the complexes are mainly stabilized by the hydrogen bonding interactions. Theories of atoms in molecules and natural bond orbital have been adopted to investigate the hydrogen bonds involved in all systems. The interaction energies of all complexes have been corrected for basis set superposition error, which are from -18.15 k J/mol to -32.99 kJ/mol. The results showed that the hydrogen bonding contribute to the interaction energies dominantly. The corresponding bonds stretching motions in all complexes are red-shifted relative to that of the inonomer, which is in agreement with experimental results.

关键词： Density functional theory Thymine hydrogen bond Catechin

Biosorption of copper ions from dilute aqueous solutions on base treated rubber (hevea brasiliensis) leaves powder: kinetics, isotherm, and biosorption mechanisms

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

Journal of Environmental Sciences 2008年第10期20卷 1168-1176页

作者： W.S.wan Ngah M.A.K.M.hanafiah School of Chemical Sciences Universiti Sains Malaysia Penang 11800 Malaysia.

The effciency of sodium hydroxide treated rubber (hevea brasiliensis) leaves powder (NhBL) for removing copper ions from aqueous solutions has been investigated. The e?ects of physicochemical parameters on biosorption capacities such as stirring speed, ph, biosorbent dose, initial concentrations of copper, and ionic strength were studied. The biosorption capacities of NhBL increased with increase in ph, stirring speed and copper concentration but decreased with increase in biosorbent dose and ionic strength. The isotherm study indicated that NhBL fitted well with Langmuir model compared to Freundlich and Dubinin-Radushkevich models. The maximum biosorption capacity determined from Langmuir isotherm was 14.97 mg/g at 27°C. The kinetic study revealed that pseudo- second order model fitted well the kinetic data, while Boyd kinetic model indicated that film diffusion was the main rate determining step in biosorption process. Based on surface area analysis, NhBL has low surface area and categorized as macroporous. Fourier transform infrared (FT-IR) analyses revealed that hydroxyl, carboxyl, and amino are the main functional groups involved in the binding of copper ions. Complexation was one of the main mechanisms for the removal of copper ions as indicated by FT-IR spectra. Ion exchange was another possible mechanism since the ratio of adsorbed cations (Cu2+ and h+) to the released cations (Na+, Ca2+, and Mg2+) from NhBL was almost unity. Copper ions bound on NhBL were able to be desorbed at > 99% using 0.05 mol/L hCl, 0.01 mol/L hNO3, and 0.01 mol/L EDTA solutions.

关键词： copper treated rubber leaves powder kinetics isotherm ion exchange desorption

Characteristics of the stabilized/solidified municipal solid wastes incineration fly ash and the leaching behavior of Cr and Pb

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2016年第1期10卷 192-200页

作者： Yan ShAO haobo hOU Guangxing wanG Sha wan Min ZhOU School of Resource and Environment Science Wuhan University Wuhan 430072 China GNSS Research Center Wuhan University Wuhan 430072 China

Fly ash is a hazardous byproduct of municipal solid wastes incineration （MSWI）. An alkali activated blast fumace slag-based cementifious material was used to stabilize/solidify the fly ash at experimental level. The characteristics of the stabilized/solidified fly ash, including metal leachability, mineralogical characteristics and the distributions of metals in matrices, were tested by toxic characteristic leaching procedure （TCLP）, X-ray diffrac- tion （XRD） and scanning electron microscopy-energy dispersive spectrometer （SEM-EDS） respectively. Contin- uous acid extraction was utilized to extract metal ions and characterize their leaching behavior. The stabilization/ solidification procedure for MSWI fly ash demonstrates a strong fixing capacity for the metals by the formation of C- S-h phase, hydrated calcium aluminosilicate and ettringite. The stabilized/solidified fly ash shows a dense and homogeneous microstructure. Cr is mainly solidified in hydrated calcium aluminosilicate, C-S-h and ettringite phase through physical encapsulation, precipitation, adsorption or substitution mechanisms, and Pb is mainly solidified in C-S-h phase and absorbed in the Si-O structure.

关键词： municipal solid waste incineration (MSWI)fly ash blast furnace slag leaching behavior Cr Pb

Effect of heat treatment on the microstructure and mechanical properties of a multidirectionally forged Mg-Gd-Y-Zn-Zr-Ag alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2023年第6期11卷 2042-2053页

作者： Junkai wang Chuming Liu Shunong Jiang Yingchun wan Zhiyong Chen School of Materials Science and Engineering Central South UniversityChangsha 410083China State Key Laboratory for Powder Metallurgy Central South UniversityChangsha 410083China School of Materials Science and Engineering Hunan University of Science and TechnologyXiangtan 411201China

Multidirectional forging(MDF)was successfully applied to fabricate large-size Mg-Gd-Y-Zn-Zr-Ag alloy in this work and effects of T4,T5 and T6 treatments on the microstructure and mechanical properties of the as-forged alloy were *** show that dynamic recrystallization(DRX)occurs and second phase particles precipitate along the grain boundary during the MDF *** annealing treatment(T4),the volume fraction and size of dynamic precipitates slightly increase at a lower temperature(430℃)compared with those of MDFed sample,while they are dissolved into theα-Mg matrix at a higher temperature(450℃).At the meantime,short plate-shaped long-period stacking ordered(LPSO)phases are observed in the DRX grains of the MDFed sample and then dissolved into theα-Mg matrix during annealing at both *** basal texture is identified in the MDFed sample,but the basal pole tilts away from final forging direction and rare-earth texture component withorientation parallel to penultimate forging direction becomes visible after *** T6 sample annealing at 430℃for 4 h and ageing at 200℃for 34 h exhibits the superior strength and ductility in this *** ultimate tensile strength,tensile yield strength and elongation to failure,which is 455 MPa,308 MPa and 7.7%,respectively,are overall improved compared with the directly-aged(T5)*** paper provides a superior heat treatment schedule to manufacture high-performance large-scale Mg-Gd-Y-Zn-Zr-Ag components for industrial production.

关键词： Mg-Gd-Y-Zn-Zr-Ag alloy Multidirectional forging Dynamic precipitation heat treatment Mechanical properties

Effect of Y content and equal channel angular pressing on the microstructure, texture and mechanical property of extruded Mg-Y alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2022年第1期10卷 210-224页

作者： W.Yang G.F.Quan B.Ji Y.F.wan h.Zhou J.Zheng D.D.Yin Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengduSichuan 610031China Nano and heterogeneous Materials Center School of Materials Science and EngineeringNanjing University of Science and TechnologyNanjing 210094China International Joint Laboratory for Light Alloys(Ministry of Education) College of Materials Science and EngineeringShenyang National Laboratory for Materials ScienceChongqing UniversityChongqing 400044China

The microstructure, texture and mechanical property evolution of the extruded Mg-x Y(x = 1, 5 wt.%) alloys during equal channel angular pressing(ECAP) were systematically investigated using an optical microscope, electron backscatter diffraction(EBSD) and uniaxial tensile test. The Mg-Y alloys exhibited a weakened basal texture before the ECAP, and the texture was further weakened with the max basal poles dispersed along ~45° between the extrusion direction and the transverse direction after the ECAP. The Mg-5 Y alloys always exhibited a finer grain size comparing to that of Mg-1 Y for the same ECAP process. With a proper ECAP process, both the strength and elongation of Mg-5 Y alloy could be improved simultaneously after the ECAP, i.e., the yield strength(273.9 ± 1.2 MPa), ultimate strength(306.4 ± 3.0 MPa),and elongation(23.9 ± 1.0%) were increased by 10%, 6%, and 72%, respectively, comparing to that before the ECAP. This was considered to be arose from the combined effects of grain refinement, significant improved microstructure homogeneity and solid solution *** addition, it was found that Mg-Y alloy with better comprehensive properties could be obtained by the decreasing-temperature ECAP processes. The yield strength-grain size relationship could be well described by the hall-Petch relation for all the ECAPed Mg-Y alloys,which was consistent with that the texture changes did not significantly affect the average Schmid factors of basal, prismatic and pyramidal slips for both Mg-Y alloys.

关键词： Mg-RE alloy Equal channel angular pressing Texture Mechanical property

Effects of water application intensity of micro-sprinkler irrigation and soil salinity on environment of coastal saline soils

在线全文

学校读者我要写书评

暂无评论

Water Science and Engineering 2020年第2期13卷 116-123页

作者： Lin-lin Chu Yao-hu Kang Shu-qin wan College of Agricultural Science and Engineering Hohai UniversityNanjing 210098China Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China

To achieve the greatest leaching efficiency,water movement must occur under unsaturated flow ***,the water application intensity of irrigation must be chosen *** aim of this study was to evaluate the impact of the water application intensity of micro-sprinkler irrigation on coastal saline soil with different salt *** achieve this objective,a laboratory experiment was conducted with three soil salinity treatments(2.26,10.13,and 22.29 dS/m)and three water application intensity treatments(3.05,5.19,and 7.23 mm/h).The results showed that the effect of soil salinity on soil water content,electrical conductivity,and ph was significant,and the effect of the water application intensity was *** soil water content was present in the 40e60 cm profile in all soil salinity treatments,and the content was higher in the medium and high water application intensity treatments than in the low-intensity *** salt leaching occurred in all treatments,and the effect was stronger in the high soil salinity treatment and medium water application intensity *** the medium and high soil salinity treatments,ph exhibited a decreasing trend,with no trend change in the low soil salinity treatment,and the ph value was higher in the medium water application intensity treatment than in the other two *** results indicated that the three intensities evaluated had no statistically different effect on the electrical conductivity of saturated soil-paste extracts(EC)in the upper 20 cm of the soil profile,and it would be better to maintain a lower value of the water application intensity.

关键词： Soil water content Salinity Micro-sprinkler irrigation Water application intensity Saline soil environment

Recent advances in the diversification of chromones and flavones by direct C-h bond activation or functionalization

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2020年第12期31卷 3073-3082页

作者： Shanghui Tian Tian Luo Yanping Zhu Jie-Ping wan College of Chemistry and Chemical Engineering Jiangxi Normal UniversityNanchang 330022China School of Pharmacy Key Laboratory of Molecular Pharmacology and Drug EvaluationMinistry of EducationCollaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of ShandongYantai UniversityYantai 264005China

Chromone and flavone are both central backbones of natural products and clinical *** of diversely functionalized chromones and flavones constitutes significant research contents of the modern synthetic science because abundant molecular libraries of such types are crucial in providing candidate compounds for the discovery of new pharmaceuticals and functional *** direct C—h bond activation or functionalization on these heterocyclic backbones provides highly powerful tools for the rapid accesses to densely functionalized chromone and flavone *** the importance of the functionalized chromone and flavone compounds as well as the notable advances in the synthesis of such products by direct C—h activation or functionalization,we review herein the research advances in the C—h bond activation and functionalization reactions of chro mone and flavones,in hope of showing the current states and promise of the research domain.

关键词： Chromones Flavones C—h bond Activation Functionalization