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Microwave-assisted polyol synthesis of LiMnPO4/C and its use as a cathode material in lithium-ion batteries

Particuology 2017年第4期15卷 42-49页

作者： Yunfei Long zhihua Zhang zhi Wu Jing su Xiaoyan lv Yanxuan Wen School of Chemistry and Chemical Engineering Guangxi University Nanning 530004 China Guangxi Colleges and Universities Key Laboratory of Novel Energy Materials and Related Technology Nanning 530004 China The New Rural Development Research Institute Guangxi University Nanning 530004 China

We synthesized LiMnPO4/C with an ordered olivine structure by using a microwave-assisted polyol process in 2：15 （v/v） water-diethylene glycol mixed solvents at 130℃ for 30min. We also studied how three surfactants-hexadecyltrimethylammonium bromide, polyvinylpyrrolidone k30 （PVPk30）, and polyvinylpyrrolidone k90 （PVPk90）-affected the structure, morphology, and performance of the prepared samples, characterizing them by using X-ray diffraction, scanning electron microscopy, trans- mission electron microscopy, charge/discharge tests, and electrochemical impedance spectroscopy. All the samples prepared with or without surfactant had orthorhombic structures with the Pnmb space group. Surfactant molecules may have acted as crystal-face inhibitors to adjust the oriented growth, morphol- ogy, and particle size of LiMnPO4. The microwave effects could accelerate the reaction and nucleation rates of LiMnPO4 at a lower reaction temperature. The LiMnPO4/C sample prepared with PVPk30 exhib- ited a flaky structure coated with a carbon layer （-2 nm thick）, and it delivered a discharge capacity of 126 mAh/g with a capacity retention ratio of -99.9% after 50 cycles at 1C. Even at 5C, this sample still had a high discharge capacity of 110 mAh/g, demonstrating good rate performance and cycle performance. The improved performance of LiMnPO4 likely came from its nanoflake structure and the thin carbon layer coating its LiMnPO4 particles. Compared with the conventional polyol method, the microwave-assisted polyol method had a much lower reaction time.

关键词： Lithium-ion batteries Cathode materials Lithium manganese phosphates Microwave-assisted polyol method

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Generation of medical isotopes ^(47)Sc,^(67)Cu through laser-induced(γ,p)reaction

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Nuclear Science and Techniques 2024年第11期35卷 219-227页

作者： Jian-Yao Zhang Di Wu Hao-yang Lan Huan-Gang Lu Jia-Xin Liu Jian-Feng lv Mei-zhi Wang Xue-Qing Yan State Key Laboratory of Nuclear Physics and Technology School of PhysicsCAPTPeking UniversityBeijing 100871China Beijing Laser Acceleration Innovation Center Beijing 101407China

Short-lived medical isotopes and their generators are typically produced in nuclear reactors and cyclotrons that require extensive ***,considering the environmental concerns and economic costs of these traditional approaches,modern laser technology,which provides extremely strong electric fields within tabletop-sized areas,can serve as a potential supplementary *** specifically on the(γ,p)generation of the vital medical isotopes^(47)Sc and^(67)Cu,we used both experimental results and PIC-GEANT4 simulations to demonstrate that laser-induced photonuclear reaction is a promising method for isotope *** developed a model capable of calculating isotope yields under various laser conditions and acceleration *** findings revealed that a 200 TW laser can sufficiently produce diagnostic amounts of^(47)Sc and^(67)Cu,while simultaneously providing high specific activity,which is significant in medical applications for improving treatment efficacy,enhancing image resolution,and reducing side effects.

关键词： Photonuclear reaction Laser-drivenγ-Ray Medical isotope

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Temperature-dependent of Nonlinear Optical Conductance of Graphene-based Systems in High-intensity Terahertz Field

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Nano-Micro Letters 2014年第2期6卷 153-162页

作者： Jing lv Rui-yang Yuan Hui Yan Laboratory of Thin Film Materials Beijing University of Technology Center of Theoretical Physics Department of PhysicsCapital Normal University

For multi-photon processed with the linear dispersion in the high-intensity terahertz(THz) field,we have systematically investigated the temperature-dependent nonlinear optical response of graphene-based systems, including single layer graphene, graphene superlattice and gapped graphene. In the intrinsic single layer graphene system, it demonstrates that, at low temperature, nonlinear optical conductivities of the thirdand fifth-order are respectively five and ten orders of magnitude larger than the universal conductivity with high-intensity and low frequency THz *** the graphene superlattice and gapped graphene systems, the optical responses enhanced because of the anisotropic massless and massive Dirac fermions.

关键词： Nonlinear Graphene Terahertz Conductance Transmittance

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A Charge-Trap Memory Device with a Composition-Modulated Zr-Silicate High-k Dielectric Multilayer Structure

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Chinese Physics Letters 2010年第6期27卷 254-257页

作者： lv Shi-Cheng GE Zhong-yang ZHOU Yue XU Bo GAO Li-Gang YIN Jiang XIA Yi-Dong LIU zhi-Guo Department of Physics and National Laboratory of Solid State Microstructures Nanjing University Nanjing 210093 Department of Materials Science and Engineering and National Laboratory of Solid State Mierostructures Nanjing University Nanjing 210093

We report a novel charge-trap memory device with a composition-modulated Zr-silicate high-k dielectric mul- tilayer structure prepared by using the pulsed laser deposition technique. The device employs amorphous （ZrO2）0.5（SiO2）0.5 as the tunneling and blocking oxide layers, and ZrO2 nanocrystals as the trapping storage layer. Zr02 nanocrystals are precipitated from the phase separation of （ZrO2）0.5（SiO2）0.2 films annealed at 800℃, and isolated from each other within the amorphous （ZrO2）0.5（SiO2）0.5 matrix. Our charge trapping device shows a memory window of 2.6 V and a stored electron density of 1×10^13/cm2.

关键词： ELECTRIC charge & distribution COMPUTER storage devices MODULATION (Electronics) ZIRCONIUM compounds MULTILAYERED thin films PULSED laser deposition AMORPHOUS substances TUNNELING (Physics) TEMPERATURE effect

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Ti_(3)C_(2)MXene:recent progress in its fundamentals,synthesis,and applications

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Rare Metals 2022年第10期41卷 3268-3300页

作者： Wei-Xin Huang zhi-Peng Li Dong-Dong Li zhi-Hui Hu Chao Wu Kang-Le lv Qin Li South-Central Minzu University Wuhan430074China Wuhan Research Institute of Materials Protection Wuhan430000China

In this rapidly developing society,it is always crucial to exploit new materials with suitable properties to meet specific application ***-dimensional(2 D)transition metal carbon/nitrides(MXenes)are a novel graphene-like material with exciting research potential in recent *** them,Ti_(3)C_(2)debuts in a central position due to its relatively longer research history,mature synthetic process,and incredibly rich store of merits,such as good flexibility,large specific surface area,abundant termination groups,excellent electrical conductivity,and light-to-heat conversion *** this review,recent research progress on Ti_(3)C_(2)MXene and its composites was updated mainly from three aspects,including their fundamentals,synthesis,and *** has been found that diverse applications of Ti3 C2-based composites are inseparable and correlated with each other,which were linked by their unique physicochemical *** the end,a summary and a perspective on future opportunities and challenges of Ti_(3)C_(2)were given to offer theoretical and technical guidelines for further investigation on MXene family.

关键词： Ti_(3)C_(2)MXene Delamination Biomedicine Battery and supercapacitor Sensor Photocatalyst

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Development of a new ferulic acid certified reference material for use in clinical chemistry and pharmaceutical analysis

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Acta Pharmaceutica Sinica B 2015年第3期5卷 231-237页

作者： Dezhi yang Fengfeng Wang Li Zhang Ningbo Gong yang lv Beijing Key Laboratory of Polymorphic Drugs Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical College

This study compares the results of three certified methods, namely differential scanning calorimetry (DSC), the mass balance (MB) method and coulometric titrimetry (CT), in the purity assessment of ferulic acid certified reference material (CRM). Purity and expanded uncertainty as determined by the three methods were respectively 99.81%, 0.16%; 99.797, 0.16%; and 99.81%, 0.26% with, in all cases, a coverage factor (k) of 2 (P=95%). The purity results are consistent indicating that the combination of DSC, the MB method and CT provides a confident assessment of the purity of suitable CRMs like ferulic acid. (C) 2015 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V.

关键词： Differential scanning calorimetry Mass blance Coulometric titrimetry Certified reference material Uncertainty ferulic acid

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Photocatalytic HER Performance of TiO_(2)-supported Single Atom Catalyst Based on Electronic Regulation:A DFT Study

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Chemical Research in Chinese Universities 2022年第4期38卷 1025-1031页

作者： SONG Weiyu lv Xintong GAO yang WANG Lu State Key Laboratory of Heavy Oil Processing College of ScienceChina University of Petroleum-BeijingBeijing102249P.R.China

Hydrogen is a kind of sustainable clean ***-driven hydrogen evolution reaction(HER)from water splitting assisted by photocatalysts is very crucial for developing clean energy ***-atom catalysts,such as atomically dispersed Pt on anatase(Pt1/TiO_(2))have exhibited excellent photocatalytic HER ***,the role of a single atom is still *** mechanism of photocatalytic HER of TiO_(2)-supported noble metal single-atom catalysts has been *** supported single-atom Pt could narrow the bandgap of TiO_(2),enhance the optical absorption properties,and promote the transfer of the excited *** electrons do not participate in the process of O-H cleavage,but can participate in the process of proton reduction and greatly reduce the hydrogen evolution energy ***,the hydrogen evolution energy can be used as a descriptor to evaluate the activity of TiO_(2)-supported single-atom *** activity of hydrogen evolution is found to be related to the number of d-band electrons of the single noble atom on M1/TiO_(2)(M=Pd,Pt,Rh,Ir).The increase of the number of d electrons in the single atom could reduce the hydrogen evolution energy and promote the hydrogen evolution process.

关键词： TiO2 Single-atom catalyst Photocatalysis Density functional theory

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Design and modification of metal sulfide-based catalysts for lithiumsulfur batteries

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Particuology 2024年第3期86卷 86-100页

作者： Yufei Zhao Chuannan Geng Li Wang Haotian yang Wei lv Quan-Hong yang Nanoyang Group State Key Laboratory of Chemical EngineeringSchool of Chemical Engineering and TechnologyNational Industry-Education Integration Platform of Energy Storageand Collaborative Innovation Center of Chemical Science and Engineering(Tianjin)Tianjin UniversityTianjin300072China Shenzhen Geim Graphene Center Engineering Laboratory for Functionalized Carbon MaterialsTsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen518055China Haihe Laboratory of Sustainable Chemical Transformations Tianjin300192China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityFuzhou350207China

Metal sulfide(MS)have good conductivity,strong adsorption ability,and excellent catalytic activity for the conversion of sulfur species,and thus,show great promise as the catalysts in LieS ***,the relationship between their properties and electrochemical performance is still ***,further in-depth discussions are required to improve their design in Li-S *** review systematically summarizes the basic structural and electrochemical properties of MSs and highlights the advantages that guarantee them as high-performance catalysts in Li-S ***,various modification strategies for MSs to enhance the catalytic activity,efficiency,and stability are also *** last,future opportunities for MS catalysts in Li-S batteries are proposed.

关键词： Lithium-sulfur battery Metal sulfide Catalysis

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H-hop independently submodular maximization problem with curvature

High-Confidence Computing

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High-Confidence Computing 2024年第3期4卷 75-81页

作者： yang lv Chenchen Wu Dachuan Xu Ruiqi yang Beijing Institute for Scientific and Engineering Computing Beijing University of TechnologyBeijing 100124China College of Science Tianjin University of TechnologyTianjin 300382China

The Connected Sensor Problem(CSP)presents a prevalent challenge in the realms of communication and Internet of Things(IoT)*** primary aim is to maximize the coverage of users while maintaining connectivity among K *** the challenge of managing a large user base alongside a finite number of candidate locations,this paper proposes an extension to the CSP:the h-hop independently submodular maximization problem characterized by curvatureα.We have developed an approximation algorithm that achieves a ratio of 1−e−α/(2h+3)α.The efficacy of this algorithm is demonstrated on the CSP,where it shows superior performance over existing algorithms,marked by an average enhancement of 8.4%.

关键词： Internet of things UAV communication Approximation algorithms

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The pyrolysis preparation of the compact and full-coverage AgSbS_(2) thin films and the photovoltaic performance of the corresponding solar cells

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Journal of Materials Science & Technology 2022年第3期98卷 268-271页

作者： Kai lv Chengwu Shi yang yang Qi Wang Xun Sun Wangchao Chen School of Chemistry and Chemical Engineering Anhui Province Key Laboratory of Advanced Catalytic Materials and Reaction EngineeringHefei University of TechnologyHefei 230009China

The preparation of the compact and full-coverage AgSbS;thin films is firstly reported using the pyrolysis of the Ag-butyldithiocarbamate and Sb-butyldithiocarbamate complex solution in *** influence of the preparation temperature on the crystal phase,optical absorption,morphology of the AgSbS;thin films is systematically *** AgSbS;thin films at 150°C for 30 min are composed of the individual nanoparticles with the particle sizes of 30–60 *** the AgSbS_(2)thin films are further heated at 350℃for 2 min,the individual AgSbS_(2)nanoparticles are melted together and the grain boundary between the AgSbS_(2)nanoparticles *** solar cells with the architecture of FTO/compact TiO_(2)/AgSbS_(2)/spiro-OMe TAD/Au achieve the photoelectric conversion efficiency(PCE)of 2.09%,along with the open-circuit voltage of 0.44 V,the short-circuit photocurrent density of 10.49 m A cm^(-2),the fill factor of *** PCE of 2.09%is the highest value for the AgSbS_(2)solar cells.

关键词： AgSbS_(2)thin film Ag-butyldithiocarbamate Sb-butyldithiocarbamate Pyrolysis Solar cell

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