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Selective oxidation mediated synthesis of unique SexTey nanotubes, their assembled thin films and photoconductivity

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Nano Research 2018年第2期11卷 665-675页

作者： Yang, yuan Liu, Guo-Qiang Gao, Min-Rui xia, yu yu, Shu-Hong Division of Nanomaterials and Chemistry Hefei National Laboratory for Physical Sciences at the Microscale Collaborative Innovation Centre of Suzhou Nano Science and Technology CAS Centre for Excellence in Nanoscience Department of Chemistry Hefei Science Centre of CAS University of Science and Technology of China Hefei China

One-dimensional hollow nanostructures have potential applications in many fields and can be fabricated using various methods. Herein, a selective-oxidation route for the synthesis of unique SexTey nanotubes （STNTs） with a controlled morphology using TexSey@Se core-shell nanowires （TSSNWs） as a template is reported. Because of the lower redox potential of TeO2/Te compared to that of H2SeO3/Se, the Te in TSSNWs can be preferentially oxidized by an appropriate oxidant of HNO2 to form STNTs. The inner diameters and wall thicknesses of the STNTs can be tuned by modulating the core diameters and shell thicknesses of the TSSNWs, respectively. The STNTs can be assembled into a monolayer composed of well-arranged nanotubes using the Langmuir-Blodgett technique. A device based on films stacked with 10 STNT monolayers was fabricated to investigate the photocoductivity of the STNTs. The STNTs exhibited a good photoresponse over the whole ultraviolet-visible spectrum, revealing their votential for application in ovtoelectronic devices.

关键词： selective oxidation core-shell nanowires nanotubes assembled thin films photoconductivity

Chitosan derived carbon membranes as protective layers on zinc anodes for aqueous zinc batteries

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International Journal of Minerals,Metallurgy and Materials 2023年第4期30卷 621-629页

作者： Haichao Li Zengwu Wei yu xia Junshan Han Xing Li School of Materials Science and Chemical Engineering Ningbo UniversityNingbo 315211China

Aqueous zinc batteries with low cost and inherent safety are considered to be the most promising energy storage ***,they suffer from poor cycling stability and low coulombic efficiencies caused by the adverse zinc dendrites on the anodes during the discharging/charging *** is a kind of natural amino polysaccharide,which is rich in nitrogen and *** sintered at high temperatures,carbon membranes have been achieved with excellent conductivity and graphitization degree,which could enhance the ability to induce zinc ion uniform deposition to some *** this work,a type of carbon membrane using chitosan as raw materials has been fabricated by sintering,and then assembled as the protect layers in aqueous zinc *** results show that the samples could retain smoother surfaces when adopting the sintering temperature of 800℃,and the assembled batteries are able to achieve about 700 h at a current density of 0.25m A·cm^(-2),which is far longer than those of the similar batteries without any carbon membranes.

关键词： carbon membrane dendrites chitosan sintering process zinc batteries

Exfoliation and dispersion of graphene in ethanol-water mixtures

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Frontiers of Materials Science 2012年第2期6卷 176-182页

作者： Wei-Wei LIU Bao-yu xia xiao-xia WANG Jian-Nong WANG Shanghai Key Laboratory for Laser Processing and Materials Modification School of Materials Science and EngineeringShanghai Jiao Tong University800 Dong Chuan RoadShanghai 200240China School of Materials Science and Engineering Tongji University1239 Siping RoadShanghai 200092China Key Laboratory of Safety Science of Pressurized System(Ministry of Education) ScHool of Mechanical and Power EngineeringEast China University of Science and Technology130 Meilong RoadShanghai 200237China

Graphene has attracted much attention as a new nano-carbon for its unique structure and properties. However, production and dispersion of unfunctionalized graphene are still big challenges. Herein, we demonstrate a simple method for preparation and dispersion of such graphene with low cost and non toxicum. This approach is achieved by exfoliating graphite in an ethanol/water mixture and forming stable dispersion of mono- and few-layer graphenes. The ratio of ethanol/water in the mixture is found to be crucial to both the exfoliation and dispersion processes. Exfoliation in pure water or pure ethanol produces no graphene. This method avoids the conventional use of harsh oxidants and surfactants; therefore, the graphitic structure is well maintained without destruction. Benefiting from the use of ethanol and water, it can be easy to prepare transparent and conductive graphene films by vacuum filtering or spray method, and does not need special post-treatment to remove the impurity, which could be beneficial for potential applications in electronic, optic and energy areas.

关键词： graphene liquid-phase exfoliation transparent conductive film solubilityparameter

ShadowEth： Private Smart Contract on Public Blockchain

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Journal of Computer Science & Technology 2018年第3期33卷 542-556页

作者： Rui yuan yu-Bin xia Hai-Bo Chen Bin-yu Zang Jan Xie Institute of Parallel and Distributed Systems Shanghai Jiao Tong University Shanghai 200240 China Cryptape Inc. Hangzhou 310007 China

Blockchain is becoming popular as a distributed and reliable ledger which allows distrustful parties to transact safely without trusting third parties. Emerging blockchain systems like Ethereum support smart contracts where miners can run arbitrary user-defined programs. However, one of the biggest concerns about the blockchain and the smart contract is privacy, since all the transactions on the chain are exposed to the public. In this paper, we present ShadowEth, a system that leverages hardware enclave to ensure the confidentiality of smart contracts while keeping the integrity and availability based on existing public blockchains like Ethereum. ShadowEth establishes a confidential and secure platform protected by trusted execution environment （TEE） off the public blockchain for the execution and storage of private contracts. It only puts the process of verification on the blockchain. We provide a design of our system including a protocol of the cryptographic communication and verification and show the applicability and feasibility of ShadowEth by various case studies. We implement a prototype using the Intel SGX on the Ethereum network and analyze the security and availability of the system.

关键词： blockchain smart contract privacy trusted execution environment hardware-enclave

Trimetallic PtRhNi alloy nanoassemblies as highly active electrocatalyst for ethanol electrooxidation

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Nano Research 2017年第10期10卷 3324-3332页

作者： Huimin Liu Jiahui Li Lijuan Wang Yawen Tang Bao yu xia yu Chen Key Laboratory of Macromolecular Science of Shaanxi Province Shaanxi Key Laboratory for Advanced Energy Devices Shaanxi Engineering Lab for Advanced Energy Technology School of Materials Science and Engineering Shaanxi Normal University 620 Changan Road Xi'an 710062 China Jiangsu Key Laboratory of New Power Batteries Jiangsu Collaborative Innovation Center of Biomedical Functional Materials School of Chemistry and Materials Science Nanjing Normal University 1 Wenyuan Road Nanjing 210023 China A key laboratory of Material Chemistry for Energy Conversion and Storage Ministry of Education Hubei Key Laboratory of Material Chemistry and Service Failure School of Chemistry and Chemical Engineering Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology (HUST) 1037 Luoyu Road Wuhan 430074 China Shenzhen Institute of Huazhong University of Science and Technology 9 Yuexing Road Shenzhen 518000 China

Although nanostructures based on noble metal alloys are widely utilized in （electro）catalysis, their low-temperature synthesis remains an enormous challenge due to the different Nernst equilibrium potentials of metal precursors. Herein, we describe the successful synthesis of trimetallic PtRhNi alloy nanoassemblies （PtRhNi-ANAs） with tunable Pt/Rh ratios using a simple mixed cyanogel reduction method and provide a detailed characterization of their chemical composition, morphology, and structure. Additionally, the electrochemical properties of PtRhNi-ANAs are examined by cyclic voltammetry, revealing composition- dependent electrocatalytic activity in the ethanol oxidation reaction （EOR）. Compared to a commercial Pt black electrocatalyst, optimized Pt3Rh1Ni2-ANAs display remarkably enhanced EOR electrocatalytic performance in alkaline media.

关键词： cyanogel trimetallic alloy electrocatalysis activity ethanol oxidation reaction

Screening of indicator pharmaceuticals and personal care products in landfill leachates: a case study in Shanghai, China

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Frontiers of Environmental Science & Engineering 2023年第9期17卷 245-256页

作者： Xiping Kan xia yu Wentao Zhao Shuguang Lyu Shuying Sun Gang yu Qian Sui State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process School of Resources and Environmental EngineeringEast China University of Science and TechnologyShanghai 200237China State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China Advanced Interdisciplinary Institute of Environment and Ecology Beijing Normal University at ZhuhaiZhuhai 519087China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China

Identifying potential sources of pharmaceuticals and personal care products(PPCPs)in the environment is critical for the effective control of PPCP *** leachate is an important source of PPCPs in water;however,it has barely been involved in source apportionment due to the lack of indicator-PPCPs(i-PPCPs)in landfill *** study provides the first systematic framework for identifying i-PPCPs for landfill leachates based on the wide-scope target monitoring of *** number of target PPCPs increased from<20 in previous studies to 68 in the present ***-nine PPCPs were detected,with median concentrations in leachate samples ranging from below the method quantification limit(MQL)to 41μg/L,and 19 of them were rarely reported previously.A total of 29 target compounds were determined to be PPCPs of high concern by principal component analysis according to multiple criteria,including occurrence,exposure potential,and ecological *** with source-specificity and representativeness analysis,erythromycin,gemfibrozil,and albendazole showed a significant difference in their occurrence in leachate compared to other potential sources(untreated and treated municipal wastewater and livestock wastewater)and correlated with total PPCP concentrations;these were recommended as i-PPCPs for *** screening procedure can be used to develop a sophisticated source apportionment method to identify sources of PPCPs from adjacent landfills.

关键词： Landfill leachates PPCPs Indicator Screening criteria Source-specificity

SplitPass： A Mutually Distrusting Two-Party Password Manager

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Journal of Computer Science & Technology 2018年第1期33卷 98-115页

作者： yu-Tao Liu Dong Du yu-Bin xia Hai-Bo Chen Bin-yu Zang Zhenkai Liang Institute of Parallel and Distributed Systems Shanghai Jiao Tong University Shanghai 200240 China School of Computing National University of Singapore Singapore 117417 Singapore

Using a password manager is known to be more convenient and secure than not using one, on the assmnption that the password manager itself is safe. However recent studies show that most popular password managers have security vulnerabilities that may be fooled to leak passwords without users＇ awareness. In this paper, we propose a new password manager, SplitPass, which vertically separates both the storage and access of passwords into two mutually distrusting parties. During login, all the parties will collaborate to send their password shares to the web server, but none of these parties will ever have the complete password, which significantly raises the bar of a successful attack to compromise all of tile parties. To retain transparency to existing applications and web servers, SplitPass seamlessly splits the secure sockets layer （SSL） and transport layer security （TCP） sessions to process on all parties, and makes the joining of two password shares transparent to the web servers. We have implemented SplitPass using an Android phone and a cloud assistant and evaluated it using 100 apps from top free apps in the Android official market. The evaluation shows that SplitPass securely protects users＇ passwords, while incurring little performance overhead and power consumption.

关键词： password manager privacy protection mobile-cloud system

Study on Micron Porous Copper Prepared by Physical Vacuum Dealloying

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Acta Metallurgica Sinica(English Letters) 2016年第12期29卷 1144-1147页

作者： Yi-Bin Ren yu-xia Sun Ke Yang Institute of Metal Research Chinese Academy of SciencesShenyang 110016 China Shenyang Aerospace University Shenyang 110136 China

Porous copper was prepared successfully by physical vacuum dealloying method using the CuZn alloy pre- cursors （Cu30Zn70, Cu40Zn60 and Cu50Zn50 alloys）. The micron porous copper showed a three-dimensional continuous porous structure with 1-5 μm pore size. With the increase of the Zn content in the CuZn alloy, the pore structure of the porous copper was more uniform and ordered. Temperature was the key factor for physical dealloying, and the optimized temperature was 500 ℃ for the CuZn alloy. The pores would fuse and disappear when the temperature was over 500 ℃. Physical vacuum dealloying was an effective preparation method for porous copper, which can be used to prepare other porous metals based on the sublimation and the Kirkendall effect.

关键词： Dealloying Sublimation Kirkendall effect Porous copper Cu-Zn alloy

DNA methylation detection methods used in colorectal cancer

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World Journal of Clinical Cases 2019年第19期7卷 2916-2929页

作者： yu-xia Zhan Guang-Hua Luo Comprehensive Laboratory Changzhou Key Lab of Individualized Diagnosis and Treatment Associated with High Technology Research the Third Affiliated Hospital of Soochow University

Colorectal cancer(CRC)remains a major contributor to the number of cancerrelated deaths that occur annually *** the development of molecular biology methods,an increasing number of molecular biomarkers have been identified and *** is believed to result from an accumulation of epigenetic changes,and detecting aberrant DNA methylation patterns is useful for both the early diagnosis and prognosis of *** studies are focusing on the development of DNA methylation detection methods or DNA methylation ***,this review will discuss the commonly used techniques and technologies to evaluate DNA methylation,their merits and deficiencies as well as the prospects for new methods.

关键词： Colorectal cancer Cancer screening Marker DNA methylation detection