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Arsenite oxidation by three types of manganese oxides

Journal of Environmental Sciences 2006年第2期18卷 292-298页

作者： feng xiong-han ZU Yan-qun TAN Wen-feng LIU Fan College of Resources and Environment Huazhong Agricultural University Wuhan 430070 China College of Resources and Environment Yunnan Agricultural University Kunming 650201 China

Oxidation of As（Ⅲ） by three types of manganese oxides and the effects ofpH, ion strength and tartaric acid on the oxidation were investigated by means of chemical analysis, equilibrium redox, X-ray diffraction （XRD） and transmission electron microscopy （TEM）. Three synthesized Mn oxide minerals, bimessite, cryptomelane, and hausmannite, which widely occur in soil and sediments, could actively oxidize As（Ⅲ） to As（Ⅴ）. However, their ability in As（Ⅲ）-oxidation varied greatly depending on their structure, composition and surface properties. Tunnel structured cryptomelane exhibited the highest ability of As （Ⅲ） oxidation, followed by the layer structured birnessite and the lower oxide hausmannite. The maximum amount of As （Ⅴ） produced by the oxidation was in the order （mmol/kg） of cryptomelane （824.2）〉 bimessite （480.4）〉 hausmannite （117.9）, As pH increased from the very low value（pH 2.5）, the amount of As（Ⅲ） oxidized by the tested Mn oxides was firstly decreased, then negatively peaked in pH 3.0 6.5, and eventually increased remarkably. Oxidation of As（Ⅲ） by the Mn oxides had a buffering effects on the pH variation in the solution. It is proposed that the oxidative reaction processes between As （Ⅲ） and biruessite（or cryptomelane） are as follows：（1） at lower pH condition：（MnO2）x＋ H3AsO3 ＋ 0.5H^＋=0.5H2AsO4^- ＋ 0.5HAsO4^2- ＋Mn〉^2＋（MnO2）x-1 ＋ H2O; （2） at higher pH condition：（MnO2）x ＋ H3AsO3 = 0.5H2AsO4^- ＋ 0.5HAsO4^2- ＋ 1.5H^＋＋（MnO2）x-1. MnO. With increase of ion strength, the As（Ⅲ） oxidized by bimessite and cryptomelane decreased and was negatively correlated with ion strength. However, ion strength had little influence on As （Ⅲ） oxidation by the hausmarmite. The presence of tartaric acid promoted oxidation of As（Ⅲ） by birnessite. As for cryptomelane and hansmannite, the same effect was observed when the concentration of tartaric acid was below 4 mmol/L, otherwise the oxidized As（Ⅲ） decreased. These findings are of great significance in improving our understanding

关键词： oxidation of As(Ⅲ) As(Ⅴ) Mn oxides pH ion strength tartaric acid

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Exploratory study of logistics service quality scale based on online shopping malls

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第6期8卷 926-931页

作者： feng Yi-xiong ZHENG Bing TAN Jian-rong State Key Lab. of CAD ＆ CG Zhejiang University Hangzhou 310027 China College of Economics ＆ Management Dalian University Dalian 116622 China

Online shopping has already become the new mode that a lot of customers try to adopt. At the same time, the online shopping could not be successfully completed without logistics service. Logistics service quality (LSQ) has significant impact on revenue and profitability. This paper presents the issue from the perspective of the customer, and explores the initial factors of LSQ based on the online shopping through in-depth interview and the Delphi method. The survey uses a standard 7-point Likert-type scale to measure the LSQ. Empirical research results are shown in detail to confirm seven LSQ dimensions with Chinese characteristics, including timeliness quality, personal contact quality, order quality, order discrepancy handling, order condition and convenience. Statistical analyses of the investigation were conducted to test the reliability and validity of the LSQ evaluation model.

关键词： Online shopping Logistics service Logistics service quality (LSQ) Dimensions of LSQ

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Estimation of the anisotropy of hydraulic conductivity through 3D fracture networks using the directional geological entropy

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International Journal of Mining Science and Technology 2024年第2期34卷 137-148页

作者： Chuangbing Zhou Zuyang Ye Chi Yao Xincheng Fan feng xiong School of Infrastructure Engineering Nanchang UniversityNanchang 330031China b School of Resource and Environmental Engineering Wuhan University of Science and TechnologyWuhan 430081China School of Engineering China University of GeosciencesWuhan 430074China

With an extension of the geological entropy concept in porous media,the approach called directional entrogram is applied to link hydraulic behavior to the anisotropy of the 3D fracture networks.A metric called directional entropic scale is used to measure the anisotropy of spatial order in different *** with the traditional connectivity indexes based on the statistics of fracture geometry,the directional entropic scale is capable to quantify the anisotropy of connectivity and hydraulic conductivity in heterogeneous 3D fracture *** to the numerical analysis of directional entrogram and fluid flow in a number of the 3D fracture networks,the hydraulic conductivities and entropic scales in different directions both increase with spatial order(i.e.,trace length decreasing and spacing increasing)and are independent of the dip *** a result,the nonlinear correlation between the hydraulic conductivities and entropic scales from different directions can be unified as quadratic polynomial function,which can shed light on the anisotropic effect of spatial order and global entropy on the heterogeneous hydraulic behaviors.

关键词： 3D fracture network Geological entropy Directional entropic scale Anisotropy Hydraulic conductivity

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Crack detection for wading-concrete structures using water irrigation and electric heating

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Frontiers of Structural and Civil Engineering 2023年第3期17卷 368-377页

作者： Jiang CHEN Zizhen ZENG Ying LUO feng xiong Fei CHENG Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province Sichuan UniversityChengdu 610065China MOE Key Laboratory of Deep Earth Science and Engineering Sichuan UniversityChengdu 610065China College of Architecture and Environment Sichuan UniversityChengdu 610065China College of Biomass Science and Engineering Sichuan UniversityChengdu 610065China

Cracking in wading-concrete structures has a worse impact on structural safety compared with conventional concrete *** accurate and timely monitoring of crack development plays a significant role in the safety of wading-concrete *** heat-transfer rate near a crack is related to the flow velocity of the fluid in the *** on this,a novel crack-identification method for underwater concrete structures is *** method uses water irrigation to generate seepage at the interface of a crack;then,the heat-dissipation rate in the crack area will increase because of the convective heat-transfer effect near the *** information can be identified by monitoring the cooling law and leakage flow near *** proposed mobile crack-monitoring system consists of a heating system,temperature-measurement system,and irrigation system.A series of tests was conducted on a reinforcedconcrete beam using this *** crack-discrimination indexψwas defined,according to the subsection characteristics of the heat-source cooling *** effects of the crack width,leakage flow,and relative positions of the heat source and crack onψwere *** results showed that the distribution characteristics ofψalong the monitoring line could accurately locate the crack,but not quantify the crack ***,the leakage flow is sensitive to the crack width and can be used to identify it.

关键词： structural health monitoring underwater concrete structure fiber Bragg grating crack detection temperature tracer method

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Identification and prioritization of key health hazards to workers in roadway construction

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Transportation Safety and Environment 2022年第2期4卷 76-87页

作者： Shicong Mo Yuhong Wang feng xiong Department of Civil and Environment Engineering The Hong Kong Polytechnic UniversityHung Hom 999077Hong Kong SARChina College of Architecture and Environment Sichuan UniversityChengdu 610065China.

Although various rating systems have been developed to promote sustainable development in roadway construction,sustainability evaluation from the perspective of safeguarding workers’health is currently *** approaches were used in the study to identify and prioritize key health hazards to workers in roadway construction,including bibliometric analysis,questionnaire survey and analytic hierarchy process(AHP).Bibliometric analysis indicates that submicron particles and polycyclic aromatic compounds are the primary concerns of researchers,and ergonomics also attracts some attention.A questionnaire survey was conducted among construction workers in *** results suggest that the most frequently encountered occupational disorders by roadway construction workers are musculoskeletal disorders,heat stroke,respiratory health issues and hearing loss,and the most commonly encountered hazards are noise,dust,asphalt fumes,heat stress and some adverse working *** on associations between the health hazards and disorders were *** there are some discrepancies between the AHP scores provided by two groups of professionals in China,the commonly agreed top occupational hazards include dust,asphalt fumes,noise,high-/low-temperature stresses and chronic *** findings may be incorporated into rating systems for roadway construction to encourage the industry to adopt better practices for the well-being of workers.

关键词： sustainable construction occupational health roadway workers hazards and exposures analytic hierarchy process

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SARS-CoV-2 vaccine research and immunization strategies for improved control of the COVID-19 pandemic

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Frontiers of Medicine 2022年第2期16卷 185-195页

作者： Yiming Shao Yingqi Wu Yi feng Wenxin Xu feng xiong Xinxin Zhang Chinese Center for Disease Control and Prevention Beijing 102206China Changping Laboratory Beijing 102206China Department of Infectious Diseases Research Laboratory of Clinical VirologyNational Research Center for Translational Medicine at ShanghaiRuijin Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghai 200025China Department of Policy Science Central Committee of the Chinese Peasants and Workers Democratic PartyBeijing 100011China

The record speed at which Chinese scientists identified severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and shared its genomic sequence with the world,has greatly facilitated the development of coronavirus disease(COVID-19)diagnostics,drugs,and *** is unprecedented in pandemic control history to develop a dozen successful vaccines in the first year and to immunize over half of the global population in the second year,due to the efforts of the scientific community,biopharmaceutical industry,and regulatory agencies *** challenges are both great and multidimensional due to the rapid emergence of virus variants and waning of vaccine *** strategies need to adapt to these challenges to keep population immunity above the herd immunity threshold,by increasing vaccine coverage,especially for older adults and young people,and providing timely booster doses with homologous or heterologous vaccine *** research should be undertaken to develop more effective vaccines against SARS-CoV-2 variants and to understand the best prime-boost vaccine combinations and immunization strategies to provide sufficient and sustainable immune protection against COVID-19.

关键词： COVID-19 pandemics SARS-CoV-2 vaccination

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Assessment of Building External Wall Thermal Performance Based on Temperature Deviation Impact Factor under Discontinuous Radiant Heating

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Journal of Thermal Science 2019年第6期28卷 1129-1140页

作者： YANG Jie WANG Jun xiong feng LIANG Hao LI Yunzhang College of Architecture and Environment Sichuan UniversityChengdu 610065China Center of Science and Technology Industrial Development Ministry of Housing and Urban-Rural DevelopmentBeijing 100835China

As the variation and timely meeting thermal environment requirement of indoor air temperature has a close relationship with the thermal performance of building external wall under discontinuous radiant heating condition, one appropriate assessment method or index for assessing the building external wall thermal performance is very necessary. In order to reasonably evaluate the thermal performance of external wall under discontinuous radiant heating condition and build the direct connections and interactions among the indoor air temperature, external wall inner surface temperature and outdoor air temperature, the first and second impact factors of temperature deviation were established, based on one mathematical model of room heat transfer. For one experimental room and four types of external walls under discontinuous radiant heating condition, both the influence of the external wall inner surface temperature deviation on the indoor air temperature and that of the outdoor air temperature deviation on the external wall inner surface temperature were determined effectively with the first and second impact factors of temperature deviation. In addition, favourable performance for the self-insulation and inner insulation walls were found, due to their superiority in effectively and timely improving the indoor thermal environment under discontinuous radiant heating condition.

关键词： temperature deviation impact factor building external wall thermal performance discontinuous radiant heating

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Silica optical fiber integrated with two-dimensional materials:towards opto-electro-mechanical technology

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Light(Science & Applications) 2021年第5期10卷 767-784页

作者： Jin-hui Chen Yi-feng xiong Fei Xu Yan-qing Lu Institute of Electromagnetics and Acoustics Xiamen UniversityXiamen 361005China College of Engineering and Applied Sciences National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

In recent years,the integration of graphene and related two-dimensional(2D)materials in optical fbers have stimulated signifcant advances in ll-fber photonics and *** conventional passive silia fiber devices with 2D materials are empowered for enhancing light-matter interactions and are applied for manipulating light beams in respect of their polarization,phase,intensity and frequency,and even realizing the active photo-electric conversion and electro-optic modulation,which paves a new route to the integrated multifunctional ll-fber optoelectronic *** article reviews the fast-progress field of hybrid 2D-materials-optical fiber for the opto-electro-mechanical *** challenges and opportunities in this field for future development are discussed.

关键词： fiber optical polarization

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Thermal-, photo- and electron-induced reactivity of hydrogen species on rutile TiO_2(110) surface: Role of oxygen vacancy

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Chinese Chemical Letters 2018年第6期29卷 752-756页

作者： Zongfang Wu feng xiong Zhengming Wang Weixin Huang Hefei National Laboratory for Physical Sciences at the Microscale CAS Key Laboratory of Materials for Energy Conversion and Department of Chemical Physics University of Science and Technology of China

Interaction of hydrogen with TiO2 plays a vital role in TiO2-based photocatalysis and thermal catalysis. In this work, we compared thermal-, photo-, and electron-induced reactivity of various types of hydrogen species on a rutile TiO2（110） surface formed by atomic H exposure at 320 and 115 K by means of thermal desorption spectroscopy, X-ray photoelectron spectroscopy and low energy electron diffraction. Atomic H interaction with rutile TiO2（110） at 115 K forms surface TiààH hydride, surface hydroxyl group, and chemisorbed water. Upon heating, surface TiààH hydride reacts to produce H2 while surface hydroxyl groups react to form both water and H2. Atomic H interaction with rutile TiO2（110） at 320 K strongly reduces TiO2 due to the continuous formation and desorption of water and forms surface hydroxyl groups and likely subsurface/bulk hydrogen species. Upon heating, hydrogen forms as the only gas-phase product and its desorption activation energy decreases with the subsurface/bulk reduction extent of rutile TiO2（110）. Surface Ti-H hydride exhibits photo-induced reactivity while both surface TiààH hydride and surface hydroxyl group exhibit electro-induced reactivity. These results have important implications for understanding the hydrogen-involved thermal and photo reactions on TiO2-based catalysts.

关键词： Surface chemistry Atomic H Surface Ti hydride Surface hydroxyl group Subsurface/bulk hydrogen species

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Male external genitalia growth curves and charts for children and adolescents aged 0 to 17 years in Chongqing, China

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Asian Journal of Andrology 2018年第6期20卷 567-571页

作者： Yi-Nan Wang Qmg Zeng feng xiong Yah Zeng Department of Medical Statistics and Information Management School of Public Health and Management Chongqing Medical University Chongqing 400016 China Department of Endocrinology the Children's Hospital of Chongqing Medical University Chongqing 400014 China

Genital size is a crucial index for the assessment of male sexual development, as abnormal penile or testicular size may be the earliest visible clinical manifestation of some diseases. However, there is a lack of data regarding penile and testicular size measurements for Chinese boys at all stages of childhood and puberty. This cross-sectional study aimed to develop appropriate growth curves and charts for male external genitalia among children and adolescents aged 0-17 years in Chongqing, China. A total of 2974 boys were enrolled in the present study. Penile length was measured using a rigid ruler, penile diameter was measured using a pachymeter, and testicular volume was determined using a Prader orchidometer. Age-specific percentile curves for penile length, penile diameter, and testicular volume were drawn using the generalized additive models for location, scale, and shape. Very similar growth curves were found for both penile length and penile diameter. Both of them gradually rose to 10 years of age and then sharply increased from 11 to 15 years of age. However, testicular volume changed little before the age of 10 years. This study contributes to the literature covering age-specific growth curve and charts about male external genitalia in Chinese children and adolescents. These age-related values are valuable in evaluating the growth and development status of male external genitalia and could be helpful in diagnosing genital disorders.

关键词： adolescents children generalized additive model for location scale and shape growth curves penile size testicular volume

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