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Science China Chemistry 2016年第11期59卷 1479-1485页

作者： jingwen zhang Xun Guo Sumei Yao Xinping Qiu Key Lab of Organic Optoelectronics and Molecular Engineering Department of ChemistryTsinghua University

We report a method to eliminate the irreversible capacity of 0.4Li_2MnO_3·0.6LiNi_(0.5)Mn_(0.5)O_2(Li_(1.17)Ni_(0.25)Mn_(0.583)O_2) by decreasing lithium content to yield integrated layered-spinel *** patterns,High-resolution TEM image and electrochemical cycling of the materials in lithium cells revealed features consistent with the presence of spinel phase within the *** discharged to about 2.8 V,the spinel phase of LiM_2O_4(M=Ni,Mn) can transform to rock-salt phase of Li_2M_2O_4(M=Ni,Mn) during which the tetravalent manganese ions are reduced to an oxidation state of *** the spinel phase can act as a host to insert back the extracted lithium ions(from the layered matrix) that could not embed back into the layered lattice to eliminate the irreversible capacity loss and increase the discharge *** electrochemical properties at room temperature showed a high capacity(about 275 mAh g^(-1) at 0.1 C) and exhibited good cycling performance.

关键词： Lithium ion electrode composite materials Lithium-rich material spinel phase layered phase

Microstructure-ionisation potential relationship analysis for understanding the molecular ionisation difference of natural esters during the impulse discharge via DFT calculation

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High Voltage 2024年第4期9卷 920-929页

作者： jingwen zhang Jian Hao Wenyu Ye Junyi zhang Ruijin Liao State Key Laboratory of Power Transmission Equipment Technology School of Electrical/EngineeringChongqing UniversityChongqingChina

Understanding the impulse discharge behaviour of natural ester(NE)is crucial for its safe application in high-voltage *** ionisation potential(IP)of triglycerides plays a significant role in the process of molecular ionisation during impulse discharge for *** correlation coefficients between molecular size,frontier orbital,electrostatic potential,polarity,and IP were *** the quantitative microstructure-IP model for triglycerides were built,which revealed that IP is strongly related to the highest occupied molecular orbital(HOMO)energy EHM,as well as the average value of positive electrostatic potential V_(p)(t),the average value of negative electrostatic potential V_(p)(-),and the surface area of negative electrostatic potential S(-).The HOMO and negative electrostatic potentials of saturated triglycerides are predominantly linked to the carbonyl O ***,in unsaturated triglycerides,the influence of C=C double bonds on HOMO and negative electrostatic potentials is more ***,the IP of unsaturated NE with C=C bonds is lower than that of saturated NE,rendering it more susceptible to ionisation under a strong electric field which is unfavourable for impulse breakdown *** structure-property correlation analysis is valuable for understanding ionisation mechanism during the impulse discharge breakdown of NE at the microscopic level.

关键词： electrostatic potential bonds

Generative adversarial networks enhanced location privacy in 5G networks

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Science China(Information Sciences) 2020年第12期63卷 41-52页

作者： Youyang QU jingwen zhang Ruidong LI Xiaoning zhang Xuemeng ZHAI Shui YU School of Information Technology Deakin University School of Computer Science University of Technology Sydney National Institute of Information and Communications Technology (NICT) School of Information and Communication Engineering University of Electronic Science and Technology of China Center of AI and Big Data Southeast Digital Economic Development Institute

5G networks, as the up-to-date communication platforms, are experiencing fast booming. Meanwhile, increasing volumes of sensitive data, especially location information, are being generated and shared using 5G networks for various purposes ceaselessly. Location and trajectory information in the published data has always been and will keep courting risks and attacks by malicious adversaries. Therefore, there are still privacy leakage threats by simply sharing the original data, especially data with location information, due to the short cover range of 5G signal tower. To better address these issues, we proposed a generative adversarial networks(GAN) enhanced location privacy protection model to cloak the location and even trajectory information. We use posterior sampling to generate a subset of data, which is proved complying with differential privacy requirements from the end device side. After that, a data augmentation algorithm modified from classic GAN is devised to generate a series of privacy-preserving full-sized synthetic data from the central server side. With the synthetic data generated from a real-world dataset, we demonstrate the superiority of the proposed model in terms of location privacy protection, data utility, and prediction accuracy.

关键词： 5G privacy preservation generative adversarial nets differential privacy

Development of Mixed Insulation Oil as Alternative Liquid Dielectric:A Review

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1242-1258页

作者： Jian Hao jingwen zhang Wenyu Ye Ruijing Liao Lijun Yang State Key Laboratory of Power Transmission Equipment Technology School of Electrical EngineeringChongqing UniversityChongqing 400044China IEEE CSEE

Use of traditional mineral oil(MO)as a liquid insulation in transformers has spanned more than 130 ***,MO has poor heat resistance,a low ignition point,and is a non-renewable resource,which does not meet development requirements for high-performance and environmentally friendly insulation ***,researchers have explored alternatives such as natural ester(NE)and synthetic ester(SE)oils,as well as mixed insulation *** insulating oil is a blend of diverse insulating oil types,with optimal performance achieved by adjusting proportions of base *** article summarizes the innovative achievements and development of mixed insulation oil in terms of development of mixed ratio,basic physical chemical properties,electrical properties,thermal stability,and application including operation and maintenance *** these efforts,this article aims to provide recommendations for future development of mixed insulating oils to advance liquid dielectric research based on enhancement mechanisms.

关键词： Environmentally friendly insulation oil ester oils high-performance mineral oil mixed insulation oils

Pitfalls of acid leaching method for determining organic and inorganic carbon contents in marine sediments

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Acta Oceanologica Sinica 2020年第8期39卷 96-102页

作者： Chen Ling Zhifei Liu jingwen zhang Yulong Zhao Yanwei zhang Adrian RFernandez State Key Laboratory of Marine Geology Tongji UniversityShanghai 200092China

Organic and inorganic carbon contents of marine sediments are important to reconstruct marine productivity,global carbon cycle, and climate change. A proper method to separate and determine organic and inorganic carbons is thus of great necessity. Although the best method is still disputable, the acid leaching method is widely used in many laboratories because of its ease-of-use and high accuracy. The results of the elemental analysis of sediment trap samples reveal that organic and inorganic carbon contents cannot be obtained using the acid leaching method, causing an infinitely amplified error when the carbon content of the decarbonated sample is 12%±1% according to a mathematical derivation. Acid fumigation and gasometric methods are used for comparison, which indicates that other methods can avoid this problem in organic carbon analysis. For the first time, this study uncovers the pitfalls of the acid leaching method, which limits the implication in practical laboratory measurement, and recommends alternative solutions of organic/inorganic carbon determination in marine sediments.

关键词： marine sediments organic carbon inorganic carbon acid leaching method limitation

Breaking 12% efficiency in flexible organic solar cells by using a composite electrode

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Science China Chemistry 2019年第7期62卷 851-858页

作者： Guang Zeng jingwen zhang Xiaobin Chen Hongwei Gu Yaowen Li Yongfang Li Laboratory of Advanced Optoelectronic Materials College of Chemistry Chemical Engineering and Materials Science Soochow University Suzhou 215123 China College of Chemistry Chemical Engineering and Materials Science Soochow University Suzhou 215123 China Beijing National Laboratory for Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China College of Materials Science and Engineering Nanchang Hangkong University Nanchang 330063 China

The performance of flexible organic solar cells(OSCs)significantly relies on the quality of transparent flexible ***,we used silver nanowires(AgNWs)with various weight ratios to dope high-conductive poly(3,4-ethylenedioxythiophene):polystyrene sulfonate(PH1000)to optimize the optical and electronic properties of PH1000 film.A high-quality flexible composite electrode PET/Ag-mesh/PH1000:AgNWs-20 with smooth surface,a low sheet resistance of 6Ω/sq and a high transmittance of 86%at 550-nm wavelength was obtained by doping 20 wt%AgNWs to PH1000(PH1000:AgNWs-20).The flexible OSCs based on the PET/Ag-mesh/PH1000:AgNWs-20 electrode delivered a power conversion efficiency(PCE)of12.07%with an open circuit voltage(Voc)of 0.826 V,a short-circuit current density(Jsc)of 20.90 m A/cm2and a fill factor(FF)of69.87%,which is the highest reported PCE for the flexible indium-tin oxide(ITO)-free *** work demonstrated that the flexible composite electrodes of PET/Ag-mesh/PH1000:AgNWs are promising alternatives for the conventional PET/ITO electrode,and open a new avenue for developing high-performance flexible transparent electrode for optoelectronic devices.

关键词： flexible electrodes flexible organic solar cells silver nanowire composite electrode power conversion efficiency

Ultrasound-assisted emulsification solidified floating organic drop microextraction for the determination of trace amounts of copper in water samples

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Frontiers of Environmental Science & Engineering 2010年第2期4卷 187-195页

作者： Qingyun CHANG jingwen zhang Xin DU Jingjun MA Jingci LI Hebei Key Laboratory of Bioinorganic Chemistry College of ScienceAgricultural University of HebeiBaoding 071001China

A simple and efficient liquid-phase microextraction(LPME)technique was developed using ultrasound-assisted emulsification solidified floating organic drop microextraction(USAE-SFODME)combined with flame atomic absorption spectrometry,for the extraction and determination of trace copper in water samples.1-(2-Pyridylazo)-2-naphthol(PAN)was used as chelating *** efficiency factors(including extraction solvent type,extraction volume,time,temperature,and pH),the amount of the chelating agent,and salt effect were investigated and *** the optimum extraction conditions,figures of merit of the proposed method were *** calibration graph was linear in the range of 20–600 mg·L^(–1)with a detection limit of 0.76 mg·L^(–1).The relative standard deviation(R.S.D)for ten replicate measurements of 20 and 400 mg·L^(–1)of copper was 3.83%and 2.65%,***,the proposed method was applied to tap water,river water,and sea water,and accuracy was assessed through the analysis of certified reference water or recovery experiments.

关键词： ultrasound-assisted emulsification solidified floating organic drop microextraction flame atomic absorption spectrometry preconcentration copper

Copper-based nanomaterials as peroxidase candidates for intelligent colorimetric detection and antibacterial applications

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Particuology 2024年第1期84卷 126-135页

作者： Yanyan Huang Huimin Zhong Cong Jiang Jiahui Yang jingwen zhang Fei Zhao Chaoqun Liu College of Light Industry and Food Engineering Nanjing Forestry UniversityNanjing210037China College of Pharmacy Institutes of Environment and MedicineHenan UniversityKaifeng475004China

With natural polyphenol compound tannic acid(TA)as the ingredient,copper tannate(CuTA)nanolayer material was formed by self-assembly under the conditions of heating and copper *** ion and tannic acid could coordinate to form Cu-O-C structure which was similar to the Fe-N-C structure of natural heme *** addition,the obtained CuTA nanomaterial possessed excellent peroxidase-like catalytic activity and *** on this excellent enzymatic activity,CuTA nanomaterials could be used for colorimetric detection of hydrogen peroxide with a smartphone and decomposition of organic *** on the structural characteristics and catalytic activity,the copper tannate nanozymes could also serve as potential antibacterial reagents to effectively inhibit the growth of gram-negative and positive bacteria in a low hydrogen peroxide *** work may promote the exploration of novel peroxidase mimetics and broaden the applications of nanozymes.

关键词： Nanozyme Colorimetric detection Smartphone Antibacteria

High-gravity intensified iron-carbon micro-electrolysis for degradation of dinitrotoluene

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Frontiers of Chemical Science and Engineering 2022年第11期16卷 1595-1605页

作者： Jiaxin Jing Weizhou Jiao Zhixing Li Kechang Gao jingwen zhang Gaomiao Ren Youzhi Liu Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering North University of ChinaTaiyuan 030051China

The application of iron–carbon(Fe–C)micro-electrolysis to wastewater treatment is limited by the passivation potential of the Fe–C *** order to address this problem,high-gravity intensified Fe–C micro-electrolysis was proposed in this study for degradation of dinitrotoluene wastewater in a rotating packed bed(RPB)using commercial Fe–C particles as the *** effects of reaction time,high-gravity factor,liquid flow rate and initial solution pH were *** degradation intermediates were determined by gas chromatography-mass spectrometry,and the possible degradation pathways of nitro compounds by Fe–C micro-electrolysis in RPB were also *** is found that under optimal conditions,the removal rate of nitro compounds reaches 68.4%at 100 *** removal rate is maintained at approximately 68%after 4 cycles in RPB,but it is decreased substantially from 57.9%to 36.8%in a stirred tank *** is because RPB can increase the specific surface area and the renewal of the liquid–solid interface,and as a result the degradation efficiency of Fe–C micro-electrolysis is improved and the active sites on the Fe–C surface can be regenerated for continuous *** conclusion,high-gravity intensified Fe–C micro-electrolysis can weaken the passivation of Fe–C particles and extend their service life.

关键词： high-gravity technology rotating packed bed Fe–C micro-electrolysis dinitrotoluene wastewater active sites

Chemical characteristics and source apportionment of PM_(2.5) in a petrochemical city: Implications for primary and secondary carbonaceous component

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Journal of Environmental Sciences 2021年第5期33卷 322-335页

作者： Guangxuan Yan Puzhen zhang Jie Yang jingwen zhang Guifen Zhu Zhiguo Cao Jing Fan Zirui Liu Yuesi Wang School of Environment Henan Normal UniversityKey Laboratory for Yellow River and Huai River Water Environment and Pollution ControlMinistry of EducationHenan Key Laboratory for Environmental Pollution ControlXinxiang 453007China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of ScienceBeijing 100029China Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of ScienceXiamen 361021China University of Chinese Academy of Science Beijing 100049China

To study the pollution features and underlying mechanism of PM_(2.5) in Luoyang, a typical developing urban site in the central plain of China, 303 PM_(2.5) samples were collected from April 16 to December 29, 2015 to analyze the elements, water soluble inorganic ions, organic carbon and elemental carbon. The annual mean concentration of PM_(2.5) was 142.3 μg/m^(3), and 75% of the daily PM_(2.5) concentrations exceeded the 75 μg/m^(3). The secondary inorganic ions, organic matter and mineral dust were the most abundant species, accounting for 39.6%, 19.2% and 9.3% of the total mass concentration, respectively. But the major chemical components showed clear seasonal dependence. SO_(4)^(2-) was most abundant specie in spring and summer, which related to intensive photochemical reaction under high O_3 concentration. In contrast, the secondary organic carbon and ammonium while primary organic carbon and ammonium significantly contributed to haze formation in autumn and winter, respectively. This indicated that the collaboration effect of secondary inorganic aerosols and carbonaceous matters result in heavy haze in autumn and winter. Six main sources were identified by positive matrix factorization model: industrial emission, combustion sources, traffic emission, mineral dust, oil combustion and secondary sulfate, with the annual contribution of 24%, 20%, 24%, 4%, 5% and 23%, respectively. The potential source contribution function analysis pointed that the contribution of the local and short-range regional transportation had significant impact. This result highlighted that local primary carbonaceous and precursor of secondary carbonaceous mitigation would be key to reduce PM_(2.5) and O_3 during heavy haze episodes in winter and autumn.

关键词： PM_(2.5) Seasonal variations Positive matrix factorization Emission sources