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| 1 | Pathological evidence for residual SARS-CoV-2 in pulmonary tissues of a ready-for-discharge patient显示文摘Dear Editor,SARS-CoV-2,a novel coronavirus and causing COVID-19,has given rise to a worldwide pandemic.1,2 So far,tens of thousands of COVID-19 patients have been clinically cured and discharged,but multiple COVID-19 cases showed SARS-CoV-2 positive again in discharged patients,3 which raises an attention for the discharged patients.Also,there is an urgent need to understand the pathogenesis of SARS-CoV-2 infection.Here,we conducted postmortem pathologic study in a ready-fordischarge COVID-19 patient who succumbed to sudden cardiovascular accident.Pathological examination revealed SARSCoV-2-viruses remaining in pneumocytes and virus-caused pathological changes in the lungs.Our study provided new insights into SARS-CoV-2 pathogenesis and might facilitate the improvement of clinical guideline for virus containment and disease management. | Xiao-Hong Yao Zhi-Cheng He Ting-Yuan Li Hua-Rong Zhang Yan Wang Huaming Mou Qiaonan Guo Shi-Cang Yu Yanqing Ding Xindong Liu Yi-Fang Ping Xiu-Wu Bian | 2020 | Cell Research2020,30,6: | 35 |
| 2 | Output feedback control of hypersonic vehicles based on neural network and high gain observer显示文摘In this paper,the output feedback control problem for a genetic hypersonic vehicle is considered under the restriction that only the vehicle's velocity and altitude are measurable. High gain observers (HGO) are utilized to provide estimation signals for unmeasurable derivatives of the vehicle's velocity and altitude. Neural network based feedforward function is designed to compensate for model uncertainties. The proposed control design require less knowledge of the hypersonic vehicle's dynamic model. A comprehensive stability analysis of the closed loop system under the output feedback control is carried to prove that the proposed control law yields semiglobal uniformly ultimately bounded tracking while keeping all the closed loop signals bounded. Numerical simulation results are presented to validate the proposed control design. | LI XinDong KIAN Bin DIAO Chen YU YanPing YANG KaiYan ZHANG Yao | 2011 | Science China(Information Sciences)2011,54,3: | 20 |
| 3 | An Improved Dynamic Core for a Non-hydrostatic Model System on the Yin-Yang Grid显示文摘A 3D dynamic core of the non-hydrostatic model GRAPES(Global/Regional Assimilation and Prediction System) is developed on the Yin-Yang grid to address the polar problem and to enhance the computational efficiency. Three-dimensional Coriolis forcing is introduced to the new core, and full representation of the Coriolis forcing makes it straightforward to share code between the Yin and Yang subdomains. Similar to that in the original GRAPES model, a semi-implicit semi-Lagrangian scheme is adopted for temporal integration and advection with additional arrangement for cross-boundary transport. Under a non-centered second-order temporal and spatial discretization, the dry nonhydrostatic frame is summarized as the solution of an elliptical problem. The resulting Helmholtz equation is solved with the Generalized Conjugate Residual solver in cooperation with the classic Schwarz method. Even though the coefficients of the equation are quite different from those in the original model, the computational procedure of the new core is just the same. The bi-cubic Lagrangian interpolation serves to provide Dirichlet-type boundary conditions with data transfer between the subdomains. The dry core is evaluated with several benchmark test cases, and all the tests display reasonable numerical stability and computing performance. Persistency of the balanced flow and development of both the mountain-induced Rossby wave and Rossby–Haurwitz wave confirms the appropriate installation of the 3D Coriolis terms in the semi-implicit semi-Lagrangian dynamic core on the Yin-Yang grid. | LI Xiaohan PENG Xindong LI Xingliang | 2015 | Advances in Atmospheric Sciences2015,32,5: | 11 |
| 4 | Spatial-temporal pattern changes of main agriculture natural disasters in China during 1990-2011显示文摘China is a disaster prone country, and a comprehensive understanding of change of disasters is very important for China's agricultural development. In this study, statistical techniques and geographic information system tools are employed to quantify the main agriculture disasters changes and effects on grain production in China during the period of 1990–2011. The results show that China's grain production was severely affected by disasters including drought, flood, hail, frost and typhoon. The annual area covered by these disasters reached up to 48.7×106 ha during the study period, which accounted for 44.8% of the total sown area, and about 55.1% of the per unit area grain yield change was caused by disasters. In addition, all of the disasters showed high variability, different changing trends, and spatial distribution. Drought, flood, and hail showed significantly decreasing trends, while frost and typhoon showed increasing trends. Drought and flood showed gradual changes and were distributed across the country, and disasters became more diversified from north to south. Drought was the dominated disaster type in northern China, while flood was the most important disaster type in the southern part. Hail was mainly observed in central and northern China, and frost was mainly distributed in southern China. Typhoon was greatly limited to the southeast coast. Furthermore, the resilience of grain production of each province was quite different, especially in several major grain producing areas, such as Shandong, Liaoning, Jilin and Jiangsu, where grain production was seriously affected by disasters. One reason for the difference of resilience of grain production was that grain production was marginalized in developed provinces when the economy underwent rapid development. For China's agricultural development and grain security, we suggest that governments should place more emphasis on grain production, and invest more money in disaster prevention and mitigation, especially in the major grain producing provinces. | DU Xindong JIN Xiaobin YANG Xilian YANG Xuhong XIANG Xiaomin | 2015 | Journal of Geographical Sciences2015,25,4: | 8 |
| 5 | Distribution and characteristic of PAHs in snow of Fildes Peninsula显示文摘Polycyclic aromatic hydrocarbons (PAHs) investigation in different matrices has been reported largely,whereas reports on snow samples were limited.Snow,as the main matrix in the polar region,has an important study meaning.PAHs in snow samples were analyzed to investigate the distribution and contamination status of them in the Antarctic,as well as to provide some references for global migration of PAHs.Snow samples collected in Fildes Peninsula were enriched and separated by solid-phase membrane disks and eluted by methylene dichloride,then quantified by gas chromatography/mass spectrometry.All types of PAHs were detected except for Benzo(a)pyrene.Principal component analysis method was applied to characterize them.Three factors (Naphthalene,Fluorene and Phenanthrene) accounted for 60.57%,21.61% and 9.80%,respectively.The results showed that the major PAHs sources maybe the atmospheric transportation,and the combustion of fuel in Fildes Peninsula.The comparison of concentration and types of PAHs between accumulated snow and fresh snow showed that the main compound concentrations in accumulated snow samples were higher than those in fresh ones.The risk assessment indicated that the amount of PAHs in the snow samples would not lead to ecological risk. | Guangshui Na Chunyang Liu Zhen Wang Linke Ge Xindong Ma Ziwei Yao | 2011 | Journal of Environmental Sciences2011,23,9: | 8 |
| 6 | Flexible, Porous, and Metal–Heteroatom?Doped Carbon Nanofibers as Efficient ORR Electrocatalysts for Zn–Air Battery显示文摘Developing an e cient and durable oxygen reduction electrocatalyst is critical for clean-energy technology, such as fuel cells and metal–air batteries. In this study, we developed a facile strategy for the preparation of flexible, porous, and well-dispersed metal–heteroatom-doped carbon nanofibers by direct carbonization of electrospun Zn/Co-ZIFs/PAN nanofibers(Zn/Co-ZIFs/PAN). The obtained Zn/Co and N co-doped porous carbon nanofibers carbonized at 800 °C(Zn/Co–N@PCNFs-800) presented a good flexibility, a continuous porous structure, and a superior oxygen reduction reaction(ORR) catalytic activity to that of commercial 20 wt% Pt/C, in terms of its onset potential(0.98 V vs. RHE), half-wave potential(0.89 V vs. RHE), and limiting current density(-5.26 mA cm^(-2)). In addition, we tested the suitability and durability of Zn/Co–N@PCNFs-800 as the oxygen cathode for a rechargeable Zn–air battery. The prepared Zn–air batteries exhibited a higher power density(83.5 mW cm^(-2)), a higher specific capacity(640.3 mAh g^(-1)), an excellent reversibility, and a better cycling life than the commercial 20 wt% Pt/C + RuO_2 catalysts. This design strategy of flexible porous non-precious metal-doped ORR electrocatalysts obtained from electrospun ZIFs/polymer nanofibers could be extended to fabricate other novel, stable, and easy-to-use multi-functional electrocatalysts for clean-energy technology. | Qijian Niu Binling Chen Junxia Guo Jun Nie Xindong Guo Guiping Ma | 2019 | Nano-Micro Letters2019,11,1: | 7 |
| 7 | Effects of disinhibition on spatiotemporal pattern of neuronal first recruitment in neuronal networks显示文摘The propagation of neuronal activities is a key feature to understanding information processing in networks. The analysis based on first-spikes of bursts in turn plays an important role in the research of neuronal activity propagation. Our focus here is to investigate how spatiotemporal patterns of neuronal first-spikes are affected by disinhibition. Multi-electrode arrays were used to record stimulation-evoked bursts of multiple neurons in randomly cultured neuronal networks. Both the precise timing of and the rank relationships between first-spikes were analyzed. Compared with evoked bursts in the network's native state, the precise first-spike latencies in its dis-inhibited state are more consistent and the propagation of its bursting activities is much faster. Additional points of interest are that disinhibited neuronal networks can be evoked to generate stable and distinguishable neuronal first recruitment spatiotemporal patterns specific to the stimulation site, and that the disinhibition may cause the original spatiotemporal patterns to change in a heterogeneous manner with regards to different propagation pathways. | Liangbin Pana,b,c,1, Xindong Songa,b,c,1, Guangxin Xiang a,b,c, Jing Zhua,b,c, Jing Cheng a,b,c,d,a Medical Systems Biology Research Center, Tsinghua University School of Medicine, Beijing 100084, China b Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China c National Engineering Research Center for Beijing Biochip Technology, 18 Life Science Parkway, Beijing 102206, China d State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua University, Beijing 100084, China | 2009 | Progress in Natural Science:Materials International2009,19,5: | 6 |
| 8 | Occurrence and bioaccumulation of polybrominated diphenyl ethers in sediments and paddy ecosystems of Liaohe River Basin, northeast China显示文摘Concentrations of 16 polybrominated diphenyl ether(PBDE) congeners were measured in river sediments, paddy soils and three species of paddy-field organisms(crab, loach and carp) collected from the Liaohe River Basin, northeastern China. The total contents of PBDEs(∑_(16)PBDEs) in sediments and paddy soils were in the ranges of 273.4–3246.3 pg/g dry weight(dw), and 192.1–1783.8 pg/g dw, respectively. BDE 209 was the dominant congener both in sediments and paddy soils. The concentrations of ∑_(16)PBDEs in sediments were significantly higher than those in the adjacent paddy soils, indicating a potential transport of PBDEs from river to paddy ecosystems via river water irrigation. The biota–soil accumulation factor(BSAF) was calculated as the ratio between the lipid-normalized concentration in paddyfield organisms and the total organic carbon-normalized concentration in paddy soil. The average BSAF values of ∑15PBDEs followed the sequence of crab(3.6) > loach(3.3) > carp(2.1). BDE 154 had the highest BSAF value, and a parabolic trend between BSAF values of individual PBDE congeners and their log KOWvalues was observed. In view of the fact that crab had the larger BSAF value and higher lipid content, the ecological risk and health risk for crab cultivation in paddy fields should be of particular concern. | Xindong Ma Haijun Zhang Wenjun Yao Wen Guo Depeng Li Ziwei Yao Jiping Chen | 2016 | Journal of Environmental Sciences2016,28,5: | 6 |
| 9 | Pathological changes in the lungs and lymphatic organs of 12 COVID-19 autopsy cases显示文摘Systematic autopsy and comprehensive pathological analyses of COVID-19 decedents should provide insights into the disease characteristics and facilitate the development of novel therapeutics.In this study,we report the autopsy findings from the lungs and lymphatic organs of 12 COVID-19 decedents—findings that evaluated histopathological changes;immune cell signature and inflammatory factor expression in the lungs,spleen and lymph nodes.Here we show that the major pulmonary alterations included diffuse alveolar damage,interstitial fibrosis and exudative inflammation featured with extensive serous and fibrin exudates,macrophage infiltration and abundant production of inflammatory factors(IL-6,IP-10,TNFo?and IL-I f).The spleen and hilar lymph nodes contained lesions with tissue structure disruption and immune cell dysregulation,including lymphopenia and macrophage accumulation.These findings provide pathological evidence that links injuries of the lungs and lymphatic organs with the fatal systematic respiratory and immune malfunction in critically ill COVID-19 patients. | Qian Liu Yu Shi Jun Cai Yaqi Duan Rongshuai Wang Hongyan Zhang Qiurong Ruan Jiansha Li Lei Zhao Yifang Ping Rong Chen Liang Ren Xiaochun Fei Heng Zhang Rui Tang Xi Wang Tao Luo Xindong Liu Xuequan Huang Zhenhua Liu Qilin Ao Yong Ren Jing Xiong Zhicheng He Haibo Wu Wenjuan Fu Pengnan Zhao Xinwei Chen Guoqiang Qu Yunyun Wang Xi Wang Jia Liu Dongfang Xiang Sanpeng Xu Xiaowei Zhou Qingrui Li Jinghong Ma Heng Li Jie Zhang Sizhe Huang Xiaohong Yao Yiwu Zhou Chaofu Wang Dingyu Zhang Guoping Wang Liang Liu Xiu-Wu Bian | 2020 | National Science Review2020,7,12: | 6 |
| 10 | Process and challenges of stainless steel based bipolar plates for proton exchange membrane fuel cells显示文摘Proton exchange membrane fuel cell(PEMFC)powered automobiles have been recognized to be the ultimate solution to replace traditional fuel automobiles because of their advantages of PEMFCs such as no pollution,low temperature start-up,high energy density,and low noise.As one of the core components,the bipolar plates(BPs)play an important role in the PEMFC stack.Traditional graphite BPs and composite BPs have been criticized for their shortcomings such as low strength,high brittleness,and high processing cost.In contrast,stainless steel BPs(SSBPs)have recently attracted much attention of domestic and foreign researchers because of their excellent comprehensive performance,low cost,and diverse options for automobile applications.However,the SSBPs are prone to corrosion and passivation in the PEMFC working environment,which lead to reduced output power or premature failure.This review is aimed to summarize the corrosion and passivation mechanisms,characterizations and evaluation,and the surface modification technologies in the current SSBPs research.The non-coating and coating technical routes of SSBPs are demonstrated,such as substrate component regulation,thermal nitriding,electroplating,ion plating,chemical vapor deposition,and physical vapor deposition,etc.Alternative coating materials for SSBPs are metal coatings,metal nitride coatings,conductive polymer coatings,and polymer/carbon coatings,etc.Both the surface modification technologies can solve the corrosion resistance problem of stainless steel without affecting the contact resistance,however still facing restraints such as long-time stability,feasibility of low-cost,and mass production process.This paper is believed to enrich the knowledge of high-performance and long-life BPs applied for PEMFC automobiles. | Gaoyang Liu Faguo Hou Shanlong Peng Xindong Wang Baizeng Fang | 2022 | International Journal of Minerals,Metallurgy and Materials2022,29,5: | 4 |
| 11 | Farmland dataset reconstruction and farmland change analysis in China during 1661-1985显示文摘This research reconstructs China's provincial farmland dataset in the last 300 years(1661–1985) by applying factor correction, citing replacement, linear interpolation, cohesion and contrast, man-land relationship test, farming trend test, provincial administrative area adjustment, etc. on available farmland data based on China's current provincial administrative boundary. Based on this dataset, a quantitative analysis has been applied to study the farmland amount and its change characteristics at both national and provincial level. Three conclusions are derived:(1) Along with the rapid population growth, national farmland amount has increased by about 320% in the last 300 years from 424,480 km2 in the early Qing Dynasty to 1,368,600 km2 in 1985. Comparing with global and national farmland datasets, in terms of the overall trend of national farmland growth, very low deviation exists but significant variances do appear for some provinces.(2) At the beginning of the Qing Dynasty, China's farming activities mainly existed in the Yangtze River Plain, the North China Plain, the Guanzhong Basin and the Yinchuan Plain. Thereafter, reclamation activities expanded to outer agricultural areas. Regarding of the growth rate, national farmland increase can be divided into five phases. National policy, disasters, wars, and economic development, are the main factors affecting farmland changes.(3) Significant regional variances exist in farmland changes. In the space shaped by the average farmland amount and the average annual change rate of farmland, the nation can be divided into six areas. | JIN Xiaobin CAO Xue DU Xindong YANG Xuhong BAI Qing ZHOU Yinkang | 2015 | Journal of Geographical Sciences2015,25,9: | 4 |
| 12 | Optimizing widths with PSO for center selection of Gaussian radial basis function networks显示文摘The radial basis function(RBF)centers play different roles in determining the classification capability of a Gaussian radial basis function neural network(GRBFNN)and should hold different width values.However,it is very hard and time-consuming to optimize the centers and widths at the same time.In this paper,we introduce a new insight into this problem.We explore the impact of the definition of widths on the selection of the centers,propose an optimization algorithm of the RBF widths in order to select proper centers from the center candidate pool,and improve the classification performance of the GRBFNN.The design of the objective function of the optimization algorithm is based on the local mapping capability of each Gaussian RBF.Further,in the design of the objective function,we also handle the imbalanced problem which may occur even when different local regions have the same number of examples.Finally,the recursive orthogonal least square(ROLS)and genetic algorithm(GA),which are usually adopted to optimize the RBF centers,are separately used to select the centers from the center candidates with the initialized widths,in order to testify the validity of our proposed width initialization strategy on the selection of centers.Our experimental results show that,compared with the heuristic width setting method,the width optimization strategy makes the selected centers more appropriate,and improves the classification performance of the GRBFNN.Moreover,the GRBFNN constructed by our method can attain better classification performance than the RBF LS-SVM,which is a state-of-the-art classifier. | ZHAO ZhongQiu WU XinDong LU CanYi GLOTIN Herve GAO Jun | 2014 | Science China(Information Sciences)2014,57,5: | 4 |
| 13 | A survey on online feature selection with streaming features显示文摘 | Xuegang HU Peng ZHOU Peipei LI Jing WANG Xindong WU | 2018 | Frontiers of Computer Science2018,12,3: | 4 |
| 14 | Simultaneous Extraction of Carboxylated Celulose Nanocrystals and Nanofibrils via Citric Acid Hydrolysis--A Sustainable Route显示文摘In this study, cellulose nanocrystals(CNC) with surface carboxylic groups were prepared from bleached softwood pulp by hydrolysis with concentrated citric acid at concentrations of 60 wt%~80 wt%. The solid residues from acid hydrolysis were collected for producing cellulose nanofibrils(CNF) via post high-pressure homogenization. Citric acid could be easily recovered after hydrolysis reactions through crystallization due to its low water solubility or through precipitation as a calcium salt followed by acidification. Several important properties of CNC and CNF, such as dimension, crystallinity, surface chemistry, thermal stability, were evaluated. Results showed that the obtained CNC and CNF surfaces contained carboxylic acid groups that facilitated functionalization and dispersion in aqueous processing. The recyclability of citric acid and the carboxylated CNC/CNF give the renewable cellulose nanomaterial huge potential for a wide range of industrial applications. Furthermore, the resultant CNC and CNF were used as reinforcing agents to make sodium carboxymethyl cellulose(CMC) films. Both CNC and CNF showed reinforcing effects in CMC composite films. The tensile strength of CMC films increased by 54.3% and 85.7% with 10 wt% inclusion of CNC and CNF, respectively. This study provides detailed information on carboxylated nanocellulose prepared by critic acid hydrolysis; a sustainable approach for the preparation of CNC/CNF is of significant importance for their various uses. | Chao Liu HaiShun Du Guang Yu YueDong Zhang QingShan Kong Bin Li XinDong Mu | 2017 | Paper And Biomaterials2017,2,4: | 4 |
| 15 | Web News Extraction via Tag Path Feature Fusion Using DS Theory显示文摘内容,布局式样,并且分析页与一页极大地不同到另外一个的网新闻的结构。另外,布局风格和一网新闻页的 parse 结构可以有时变化。为这些原因,怎么为巨大、异构的网新闻页与优秀抽取表演设计特征是一个挑战性的问题。我们的广泛的案例研究显示在网内容布局和他们的标签路径之间有潜在的关联。由观察启发了,我们设计抽取展示提取网新闻的一系列标签路径。因为每个特征有它的自己的力量,我们与 DS (Dempster-Shafer ) 证据理论熔化所有那些特征,然后设计内容抽取方法 CEDS。CleanEval 数据集和从著名网站随机选择的网新闻页上的试验性的结果证明有 CEDS 的 F 1-score 分别地比存在流行内容抽取方法 CETR 和 CEPR-TPR 高是 8.08% 和 3.08% 。 | Gong-Qing Wu Lei Li Xindong Wu | 2016 | Journal of Computer Science & Technology2016,31,4: | 4 |
| 16 | Long-Term Integration of a Global Non-Hydrostatic Atmospheric Model on an Aqua Planet显示文摘A global non-hydrostatic atmospheric model, i.e., GRAPES_YY(Global/Regional Assimilation and Prediction System on the Yin–Yang grid), with a semi-implicit semi-Lagrangian(SISL) dynamical core developed on the Yin–Yang grid was coupled with the physical parameterization package of the operational version of GRAPES. A3.5-yr integration was carried out on an aqua planet to assess the numerical performance of this non-hydrostatic model relative to other models. Specific aspects of precipitation and general circulation under two different sea surface temperature(SST) conditions(CONTROL and FLAT) were analyzed. The CONTROL SST peaked at the equator.The FLAT SST had its maximum gradient at about 20° latitude, giving a broad equatorial SST maximum in the tropics and flat profile approaching the equator. The tropical precipitation showed different propagation features in the CONTROL and FLAT simulations. The CONTROL showed tropical precipitation bands moving eastward with some envelopes of westward convective-scale disturbance. Less organized westward-propagating rainfall cells and bands were seen in the FLAT and the propagation of the tropical wave varied with the SST gradient. The Inter Tropical Convergence Zone(ITCZ), Hadley cell, and westerly jet core were weaker and more poleward as the SST profile flattened from the CONTROL to FLAT. The climatological structures simulated by GRAPES_YY, such as the distribution of precipitation and the large-scale circulation, fell within the bounds from other models. The stronger ITCZ precipitation, accompanied with stronger Hadley cells and convective heating in the CONTROL simulation, may be summed up as a result of stronger parameterized convection and the non-hydrostatic effects in GRAPES_YY. In addition, mechanism of the zonal mean circulation maintaining is analyzed for the different SST patterns referring the transient eddy flux. | Xiaohan LI Xindong PENG | 2018 | Journal of Meteorological Research2018,32,4: | 4 |
| 17 | Creation of artificial karyotypes in mice reveals robustness of genome organization显示文摘Dear Editor,Robertsonian(Rb)fusions contribute to the diversity in species karyotypes.However,how it occurs and propels evolution is still unknown,mainly due to the lack of a simple and efficient method for genetically manipulating chromosomes in animals.While the typical mousekaryotype(2n=40)iscompletelytelocentric exceptchromosomeY(ChrY),thewestern European subspeciesM.m.domesticus contains diverse chromosomal races,with a diploid number varying between 38 and 22 due to carrying one or multiple pairs of metacentric chromosomes,which results from the Rb fusions between two telocentricchromosomes. | Xiaoyu Merlin Zhang Meng Yan Zhenhua Yang Hao Xiang Wei Tang Xindong Cai Qigui Wu Xin Liu Gang Pei Jinsong Li | 2022 | Cell Research2022,32,11: | 3 |
| 18 | Fe-based metallic glass:An efficient and energy-saving electrode material for electrocatalytic degradation of water contaminants显示文摘Excessive consumption of electrical energy has hampered the widespread application of electrochemical technology for degradation of various contaminants. In this paper, a Fe-based metallic glass(MG) was demonstrated as a new type of electrocatalyst to effectively and economically degrade an azo dye. In comparison to other typical electrodes, Fe-based MG electrodes exhibit a minimized degradation time, and the specific energy is 4-6 orders of magnitude lower than that of dimensionally stable anode(DSA), metal-like boron-doped diamond(BDD) and other electrodes. As sacrificial electrode materials, Fe-based MGs have less specific electrode mass consumption than iron electrodes. The use of Fe-based MGs will promote the practical application of electrochemical technology and the use of MGs as functional materials. | Xindong Qin Zhengkun Li Zhengwang Zhu Huameng Fu Hong Li Aimin Wang Hongwei Zhang Haifeng Zhang | 2018 | Journal of Materials Science & Technology2018,34,12: | 3 |
| 19 | Effects of alkaline cations (M^+= Li^+, Na^+, K^+, Cs^+) on the electrochemical synthesis of polyaniline in nitric acid electrolyte显示文摘The effects of alkaline cations (M+= Li+, Na+, K+, Cs+) on the electrochemical synthesis of polyaniline were car-ried out under cyclovoltammetric conditions using nitrates of Li+, Na+, K+, and Cs+ as the supporting electrolytes. The re-sults show that the oxidation potentials of aniline in the electrolytes decrease as the protonation extent of aniline decreasesfrom the first scan, which is caused by the decrease of the ionic radius of alkaline metal ions at the same concentration ofalkaline cations. With the scan number increasing, the deposit charge Q as the characteristic growth function also dependson the protonation of aniline, and it increases with the ionic radius of alkaline cations increasing. SEM images show the ef-fect of alkaline cations on the morphology of polyaniline. It is clear that the ionic mobility of alkaline cations is furtherlower than that of H+. Alkaline cations and counter-ions were the species responsible for the enhancement of Pani electro-synthesis. Therefore, this is exactly what SEM images show: a relatively rough fibrous structure in the case of Pani-H+ sug-gesting a sponge-like structure and a highly orderly fiber-like structure in the case of Pani-M+. | WU Kezhong WANG Xindong MENG Xu | 2005 | Rare Metals2005,24,3: | 3 |
| 20 | Study of the electrochemical properties of a transition metallic ions modified electrode in acidic VOSO_4 solution显示文摘Graphite material was used as the electrode for an all-vanadium redox flow battery, and the electrode was modified by transition metallic ions to enhance its electrochemical behavior. An porous graphite composite electrode has high specific surface area and high current density. The electrode modified by transition metallic ions has improved catalysis behavior that can catalyze the V(II)-V(V) redox reaction showed by cyclic voltammograms. This article studied the impedance of the modified electrode by electrochemical impedance spectroscopy (EIS), and approved that the electrode modified by Co2+ and Mn2+ has a lower charge transfer resistance than the non-modified electrode. The effect of average particle size distribution is at lower frequencies that the slope of Warburg impedance is reduced by large particle size distribution. The voltage efficiency of the Co2+ modified electrode test cell is 81.5%, which is higher than that of the non-modified electrode. | WANG Wenhong WANG Xindong | 2007 | Rare Metals2007,26,2: | 3 |