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Preparation of Nano-crystalline Tungsten Carbide Thin Film by Magnetron Sputtering and Their Electrocatalytic Property for PNP Reduction

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Chinese Chemical Letters 2005年第11期16卷 1539-1542页

作者： hua jun ZHENG Jian guo huaNG Chun An MA Department of Applied Chemistry Research Center of Nano Science ＆ Technology Zhejiang University of Technology Hangzhou 310032

Nano-crystalline tungsten carbide thin films were deposited on Ni substrates by magnetron sputtering using WC as target material. The crystal structure and morphology of the thin films were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM） Electrochemical investigations showed that the electrode of the thin film exhibited higher electrocatalytic activity in the reaction of p-nitrophenol （PNP） reduction. FT-IR analysis indicated that p-aminophenol （PAP） was synthesized after two step reduction of PNP on nano-crystalline tungsten carbide thin film electrode.

关键词： Tungsten carbide nano-crystalline electrocatalyst p-nitrophenol.

Changes of Soil Water, Organic Matter, and Exchangeable Cations Along a Forest Successional Gradient in Southern China

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Pedosphere 2007年第3期17卷 397-405页

作者： YAN jun-hua ZHOU guo-Yi ZHANG De-Qiang CHU guo-Wei South China Institute of Botany Chinese Academy of Sciences Guangzhou 510650 （China）

Information on the distribution patterns of soil water content （SWC）, soil organic matter （SOM）, and soil exchangeable cations （SEC） is important for managing forest ecosystems in a sustainable manner. This study investigated how SWC, SOM, and SEC were influenced in forests along a successional gradient, including a regional climax （monsoon evergreen broad-leaved forest, or MEBF）, a transitional forest （coniferous and broad-leaved mixed forest, or MF）, and a pioneer forest （coniferous Masson pine （Pinus rnassoniana） forest, or MPF） of the Dinghushan Biosphere Reserve in the subtropical region of southern China. SWC, SOM, and SEC excluding Ca^2＋ were found to increase in the soil during forest succession, being highest in the top soil layer （0 to 15 cm depth） except for Na^＋. The differences between soil layers were largest in MF. This finding also suggested that the nutrients were enriched in the topsoil when they became increasingly scarce in the soil. There were no significant differences （P = 0.05） among SWC, SOM, and SEC. A linear, positive correlation was found between SWC and SOM. The correlation between SOM and cation exchange capacity （CEC） was statistically significant, which agreed with the theory that the most important factor determining SEC is SOM. The ratio of K^＋ to Na^＋ in the topsoil was about a half of that in the plants of each forest. MF had the lowest exchangeable Ca^2＋ concentration among the three forests and Ca^2＋：K^＋ in MPF was two times higher than that in MF. Understanding the changes of SWC, SOM, and CEC during forest succession would be of great help in protecting all three forests in southern China.

关键词： forest succession soil exchangeable cations soil organic matter soil water content

Comparison of Ileal Digested Production of Parental Rice and Rice Genetically Modified With Cowpeas Trypsin Inhibitor

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Biomedical and Environmental Sciences 2006年第1期19卷 42-46页

作者： jun-hua HAN YUE-XIN YANG JIAN-hua MEN LI-hua BIAN jun guo Institute of Nutrition and Food Safety Chinese Center for Disease Control and Prevention 27 Nanwei Road Beijing 100050 China

Objective To compare the ileal digestibility of protein and amino acids in parental rice and rice genetically modified with sck gene. Methods Six experimental swines were surgically fixed with a simple T-cannula at the terminal ileum and fed with parental rice and rice genetically modified with sck gene alternately. The ileum digesta were collected and analyzed for determination of apparent and true digestibility of protein and amino acids. Results The apparent and true digestibility of protein was similar in these two types of rice. Except for the apparent digestibility of lysine, there was no difference in the apparent and true digestibility of the other 17 amino acids. Conclusion The digestibility of protein and amino acids is not changed by the insertion of foreign gene, so it can meet the request of ＂substantial equivalence＂ in digestibility of protein and amino acids.

关键词： Genetically modified rice Apparent digestibility True digestibility

Review of silicon-based alloys for lithium-ion battery anodes

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International Journal of Minerals,Metallurgy and Materials 2021年第10期28卷 1549-1564页

作者： Zhi-yuan Feng Wen-jie Peng Zhi-xing Wang hua-jun guo Xin-hai Li guo-chun Yan Jie-xi Wang School of Metallurgy and Environment Central South UniversityChangsha 410083China Engineering Research Center of the Ministry of Education for Advanced Battery Materials Central South UniversityChangsha 410083China Hunan Provincial Key Laboratory of Nonferrous Value-Added Metallurgy Central South UniversityChangsha 410083China

Silicon(Si)is widely considered to be the most attractive candidate anode material for use in next-generation high-energy-density lithium(Li)-ion batteries(LIBs)because it has a high theoretical gravimetric Li storage capacity,relatively low lithiation voltage,and abundant ***,massive efforts have been exerted to improve its electrochemical *** some progress in this field has been achieved,a number of severe challenges,such as the element’s large volume change during cycling,low intrinsic electronic conductivity,and poor rate capacity,have yet to be *** to solve these problems have been attempted via the development of nanosized Si ***,reviews summarizing the work on Si-based alloys are ***,the recent progress related to Si-based alloy anode materials is *** problems associated with Si anodes and the corresponding strategies used to address these problems are first ***,the available Si-based alloys are divided into Si/Li-active and inactive systems,and the characteristics of these systems are *** special systems are also ***,perspectives and future outlooks are provided to enable the wider application of Si-alloy anodes to commercial LIBs.

关键词： silicon alloy anode lithium-ion battery

Ultrathin porous graphitic carbon nanosheets activated by alkali metal salts for high power density lithium-ion capacitors

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Rare Metals 2020年第12期39卷 1364-1373页

作者： Yu-Qing Dai Guang-Chao Li Xin-Hai Li hua-jun guo Zhi-Xing Wang guo-Chun Yan Jie-Xi Wang School of Metallurgy and Environment&College of Chemistry and Chemical Engineering Central South UniversityChangsha410083China Engineering Research Center of the Ministry of Education for Advanced Battery Materials School of Metallurgy and Environment&College of Chemistry and Chemical EngineeringChangsha410083China

Graphitic carbons with reasonable pore volume and appropriate graphitization degree can provide efficient Li+/electrolyte-transfer channels and ameliorate the sluggish dynamic behavior of battery-type carbon negative electrode in lithium-ion capacitors(LICs).In this work,onion-like graphitic carbon materials are obtained by using carbon quantum dots as precursors after sintering,and the effects of alkali metal salts on the structure,morphology and performance of the samples are *** results show that alkali metal salts as activator can etch graphitic carbons,and the specific surface area and pore size distribution are intimately related to the description of the alkali metal ***,it also affects the graphitization degree of the *** porous graphitic carbons(SGCs)obtained by NaCl activation exhibit high specific surface area(77.14 m^(2)·g^(-1))and appropriate graphitization *** is expectable that the electrochemical performance for lithium-ions storage can be largely promoted by the smart combination of catalytic graphitization and pores-creating ***-performance LICs(S-GCs//AC LICs)are achieved with high energy density of 92 Wh·kg^(-1)and superior rate capability(66.3 Wh·kg^(-1)at10 A·g^(-1))together with the power density as high as10020.2 W·kg^(-1).

关键词： Alkali metal salts activation Porous graphitic carbons Catalytic graphitization Lithium-ion capacitors

Different Patterns of Changes in the Dry Season Diameter at Breast Height of Dominant and Evergreen Tree Species in a Mature Subtropical Forest in South China

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Journal of Integrative Plant Biology 2006年第8期48卷 906-913页

作者： jun-hua Yan guo-Yi Zhou De-Qiang Zhang Xu-Li Tang Xu Wang South China Botanical Garden the Chinese Academy of Sciences Guangzhou 510650 China

Information on changes in diameter at breast height （DBH） is important for net primary production （NPP） estimates, timing of forest inventory, and forest management. In the present study, patterns of DBH change were measured under field conditions during the dry season for three dominant and native tree species in a monsoon evergreen broad-leaved forest in the Dinghushan Biosphere Reserve. For each tree species, different patterns of DBH change were observed. In the case of the fast-growing tree species Castanopsis chinensis Hance, large diurnal fluctuations occur, with a peak DBH in the early morning （around 05：00 h） that decreases to a minimum by about 14：00 h. Both Schima superba Gardn. et Chemp and Cryptocarya chinensis （Hance） Hemsh exhibited less diurnal swelling and shrinkage. Diurnal fluctuations for these species were observed on a few occasions over the period of observation. Graphical comparisons and statistical analysis of changes in DBH with meteorological variables indicate that for different trees, the different changes in DBH observed responded to different meteorological variables. Large stem changes were found to occur for Ca. chinensis trees that were associated with variations in solar radiation. However, both S. superba and Cr. chinensis were found to be less sensitive to solar radiation. Changes in the DBH of these two species were found to be controlled mainly by soil temperature and soil moisture. During the later dry season, with a lower soil temperature and soil moisture, all three tree species stopped growing and only negligible shrinkage, expansion, or fluctuation occurred, suggesting that the optimum time to measure tree growth in the Dinghushan Biosphere Reserve is the later dry season.

关键词： dendrometer band diameter at breast height (DBH) Dinghushan meteorological variables subtropical forest.

Trivalent Ni oxidation controlled through regulating lithium content to minimize perovskite interfacial recombination

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Rare Metals 2022年第1期41卷 96-105页

作者： Jin-Jin Zhao Xiao Su Zhou Mi Ying Zhang Yan-jun Hu hua-jun guo Yi-Nan Jiao Yu-Xia Zhang Yan Shi Wei-Zhong Hao Jing-Wei Wu Yi Wang Cun-Fa Gao guo-Zhong Cao School of Materials Science and Engineering School of Mechanical EngineeringShijiazhuang Tiedao UniversityShijiazhuang 050043China School of Materials Science and Engineering Hebei Key Laboratory of Material Near Net Forming TechnologyHebei University of Science and TechnologyShijiazhuang 050018China State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Materials Science and Engineering University of WashingtonSeattleWA 98195-2120USA

Organic–inorganic hybrid perovskite solar cells,one of the most promising photovoltaic devices,have made great progress in their efficiency and preparation *** this study,uniform,highly conductive Li_(n)NiO_(x)(0≤n... 详细信息

关键词： Lithium ions Ni^(3+) Oxidized defect Photocurrent Perovskite solar cells

Mechanism for capacity fading of 18650 cylindrical lithium ion batteries

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Transactions of Nonferrous Metals Society of China 2017年第7期27卷 1602-1607页

作者： Jian-liang CHENG Xin-hai LI Zhi-xing WANG hua-jun guo School of Metallurgy and Environment Central South University Changsha 410083 China

The mechanism for capacity fading of18650lithium ion full cells under room-temperature(RT)is *** capacity loss of18650cells is about12.91%*** cells after cycles are analyzed by XRD,SEM,EIS and *** measurement shows an overall increase in the cell resistance upon ***,it also presents anincreased charge-transfer resistance(Rct)for the cell cycled at *** test shows that the reversibility of lithium ioninsertion/extraction reaction is *** capacity fading for the cells cycled can be explained by taking into account the repeatedfilm formation over the surface of anode and the side *** products of side reactions deposited on separator are able toreduce the porosity of *** a result,the migration resistance of lithium ion between the cathode and anode would beincreased,leading the fading of capacity and potential.

关键词： 18650 lithium ion battery capacity fading cycle performance

Effect of SnO_2 intermediate layer on performance of Ti/SnO_2/MnO_2 electrode during electrolytic-manganese process

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Transactions of Nonferrous Metals Society of China 2017年第6期27卷 1417-1422页

作者： Xin CHEN hua-jun guo Shu-liang LUO Zhi-xing WANG Xin-hai LI School of Metallurgy and Environment Central South University Changsha 410083 China

SnO2intermediate layers were coated on the titanium(Ti)substrate by thermal *** electronmicroscope(SEM)and X-ray diffraction(XRD)results show that uniform SnO2intermediate layers with rutile crystal structure weresuccessfully *** to the results of linear sweep voltammetry(LSV),oxygen evolution potential(OEP)of theTi/SnO2/MnO2electrodes decreases with increasing SnO2content,indicating that the electro-catalytic oxidation activity of theelectrode *** service life tests results demonstrate that SnO2intermediate layer can improve the service life of theTi/SnO2/*** the content of SnO2intermediate layer increases,the cell voltage and the energy consumption decreaseapparently.

关键词： tin dioxide intermediate layer oxygen evolution potential accelerated service life cell voltage, electrolytic-manganese