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Vertical plane depth-resolved surface potential and carrier separation characteristics in flexible CZTSSe solar cells with over 12% efficiency

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Carbon Energy 2024年第3期6卷 36-52页

作者： Dae-Ho Son Ha Kyung Park Dae-Hwan kim Jin-Kyu Kang Shi-Joon Sung Dae-Kue Hwang Jaebaek Lee Dong-Hwan Jeon Yunae Cho William Jo Taeseon Lee JunHo kim Sang-Hoon Nam Kee-Jeong Yang Division of Energy Technology DGISTDaeguRepublic of Korea Research Center for Thin Film Solar Cells DGISTDaeguRepublic of Korea Department of Physics Ewha Womans UniversitySeoulRepublic of Korea Department of Physics Incheon National UniversityIncheonRepublic of Korea Department of Mechanical Engineering Massachusetts Institute of TechnologyCambridgeMassachusettsUSA

Cu2ZnSn(S,Se)4(CZTSSe)solar cells have resource distribution and economic *** main cause of their low efficiency is carrier loss resulting from recombination of photo-generated electron and *** overcome this,it is important to understand their electron-hole behavior *** determine the carrier separation characteristics,we measured the surface potential and the local current in terms of the absorber *** elemental variation in the intragrains(IGs)and at the grain boundaries(GBs)caused a band edge shift and bandgap(Eg)*** the absorber surface and subsurface,an upward Ec and Ev band bending structure was observed at the GBs,and the carrier separation was *** the absorber center,both upward Ec and Ev and downward Ec-upward Ev band bending structures were observed at the GBs,and the carrier separation was *** improve the carrier separation and suppress carrier recombination,an upward Ec and Ev band bending structure at the GBs is desirable.

关键词： carrier separation CZTSSe flexible solar cell local current surface potential

Laparoscopic resection for hepatocellular carcinoma: comparison between Middle Eastern and Western experience

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Chinese Journal of Cancer Research 2014年第3期26卷 245-246页

作者： Hong-Jin kim Man-Ki kim Department of Surgery Yeungnam University Medical Center

Laparoscopic liver resection （LLR） for hepatocellular carcinoma （HCC） is increasing in this era of minimal invasive liver surgery. LLR for HCC is currently known to be a safer procedure than it was before because of technical advances and improvement in postoperative patient management and remains the first-line treatment for HCC in compensated cirrhosis in many centers. We have the chance of analyzing the paper about the comparison between Middle Eastern and Western experience for LLR as treatment of HCC.

关键词： HCC LLR Laparoscopic resection for hepatocellular carcinoma comparison between Middle Eastern and Western experience

Outage analysis of aerial semi-grant-free NOMA systems

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Digital Communications and Networks 2024年第5期10卷 1529-1541页

作者： Hongjiang Lei Chen Zhu Ki-Hong Park Imran Shafique Ansari Weijia Lei Hong Tang Kyeong Jin kim School of Communications and Information Engineering Chongqing University of Posts and Telecommunications Chongqing Key Lab of Mobile Communications Technology CEMSE Division King Abdullah University of Science and Technology (KAUST) James Watt School of Engineering University of Glasgow Samsung Research America (SRA)

In this paper,we analyze the outage performance of Unmanned Aerial Vehicles(UAVs)-enabled downlink Non-Orthogonal Multiple Access(NOMA) communication systems with the Semi-Grant-Free(SGF) transmission scheme.A UAV provides coverage services for a Grant-Based(GB) user and one Grant-Free(GF) user is allowed to utilize the same channel resource *** analytical expressions for the exact and asymptotic Outage Probability(OP) of the GF user are *** results demonstrate that no-zero diversity order can be achieved only under stringent conditions on users' quality of service ***,an efficient Dynamic Power Allocation(DPA) scheme is proposed to relax such data rate *** analytical expressions for the exact and asymptotic OP of the GF user with the DPA scheme are ***,Monte Carlo simulation results are presented to validate the correctness of the derived analytical expressions and demonstrate the effects of the UAV's location and altitude on the OP of the GF user.

关键词： Unmanned aerial vehicle Non-orthogonal multiple access Semi-grant-free Outage probability

An experimental study on thermal characteristics of nanofluid with graphene and multi-wall carbon nanotubes

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Journal of Central South University 2015年第8期22卷 3202-3210页

作者： A.K.M Mahmudul Haque Sunghyun Kwon Junhyo kim Jungpil Noh Sunchul Huh Hanshik Chung Hyomin Jeong Department of Ocean System Engineering Gyeongsang National University Department of Marine Environmental Engineering Gyeongsang National University Department of Marine Engineering Mokpo National Maritime University Department of Energy and Mechanical Engineering Gyeongsang National UniversityInstitute of Marine Industry

High-thermal conductivity enhancement of nanofluid is one of the promising topics of the nanoscience research field. This work reports the experimental study on the preparation of graphene(GN) and multi-walled carbon nanotubes(MWCNTs) based nanofluids with the assistance of sodium dodecyl benzene sulfonate(SDBS) and sodium dodecyl sulfate(SDS) surfactants, and their thermal behaviors. The present work suggests not a solution, but a solution approach and deduces a new conclusion by trying to resolve the agglomeration problem and improve the dispersibility of nanoparticles in the base fluid. The analysis results of FESEM, thermal conductivity, diffusivity, effusivity and heat transfer coefficient enhancement ratio of nanofluid with surfactants SDS and SDBS expose strong evidence of the dispersing effect of surfactant on the making of nanofluid.

关键词： graphene carbon nanotube surfactant dispersibility thermal conductivity

T-DMB网络服务区和业务自动转换的现场测试

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世界宽带网络 2008年第10期15卷 63-64,66-68页

作者：金尚勋 Sang-Hum kim Gyu-young kim Man-Sik kim 彦洁（译）韩国广播电视系统成员不详

这篇论文介绍了韩国地面数字多媒体广播（T-DMB）业务的现场测试结果。2005年12月，韩国T-DMB商业广播电视业务首先在首尔城区投入使用并采用甚高频（VHF）频段。基于Eureka-147数字音频广播（DAB）系统的T-DMB系统，在高达300km/h的速... 详细信息

这篇论文介绍了韩国地面数字多媒体广播（T-DMB）业务的现场测试结果。2005年12月，韩国T-DMB商业广播电视业务首先在首尔城区投入使用并采用甚高频（VHF）频段。基于Eureka-147数字音频广播（DAB）系统的T-DMB系统，在高达300km/h的速度下提供流式视频（Streaming Video）、CD品质的音频和数据业务，这个成绩的实现主要是由于采用H-264视频编码以及附加信道编码和交织。为了能在各种广播频道中提供无缝的高品质业务，

关键词：广播电视业务现场测试自动转换地面数字多媒体广播 Eureka-147 服务区数字音频广播网络

Understanding the multifunctionality in Cu-doped BiVO_4 semiconductor photocatalyst

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Journal of Environmental Sciences 2019年第1期31卷 84-97页

作者： Chhabilal Regmi Yuwaraj K.Kshetri Ramesh Prasad PANDey Tae-Ho kim Gobinda Gyawali Soo Wohn Lee Department of Environmental and Biochemical Engineering Sun Moon University Department of Advanced Materials Engineering Sun Moon University Institute of Biomolecule Reconstruction Department of BT-Convergent Pharmaceutical Engineering Sun Moon University Division of Mechanics and ICT Convergence Engineering Sun Moon University

A visible light-induced, Cu-doped BiVO_4 photocatalyst was synthesized by a microwave hydrothermal method. The photocatalytic efficiency was investigated in the degradation of model water pollutants like Methylene Blue(dye) and ibuprofen(pharmaceuticals), as well as the inactivation of Escherichia coli(bacteria). The Cu-doped BiVO4 samples showed better efficiency than undoped BiVO_4, and the 1 wt.% Cu-doped BiVO_4 sample showed the best efficiency. The degradation of Methylene Blue reached 95%, while the degradation of ibuprofen reached 75%, and the inactivation of E. coli reached 85% in irradiation with visible light. The appearance of additional absorption band shoulders and widening of the optical absorption in the visible range makes the prepared powder an efficient visible light-driven photocatalyst. Moreover, the formation of an in-gap energy state just above the valance band as determined by density functional theory(DFT) first principle calculation, facilitates the wider optical absorption range of the doped system. Similarly, this in-gap energy state also acts as an electron trap, which is favorable for the efficient separation and photoexcited charge carriers' transfer process. The formation of oxygen vacancies due to doping also improved the separation of the charge carrier, which promoted the trapping of electrons and inhibited electron hole recombination, thus increasing the photocatalytic activity. No decrease in the efficiency of the 1 wt.% Cu-doped BiVO_4 photocatalyst in the degradation of ibuprofen over three consecutive cycles revealed the stability of the photocatalyst towards photocorrosion. These findings highlight the multifunctional applications of Cu-doped BiVO_4 in wastewater containing multiple pollutants.

关键词： BiVO4 Photocatalyst Methylene Blue Ibuprofen Escherichia coli First principle calculation

Quantum computation and simulation with vibrational modes of trapped ions

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Chinese Physics B 2021年第6期30卷 1-17页

作者： Wentao Chen Jaren Gan Jing-Ning Zhang Dzmitry Matuskevich Kihwan kim Department of Physics Tsinghua UniversityBeijing 100084China Centre for Quantum Technologies National University of Singapore3 Science Drive 2117543 SingaporeSingapore Beijing Academy of Quantum Information Sciences Beijing 100193China Department of Physics National University of Singapore2 Science Drive 3117551 SingaporeSingapore

Vibrational degrees of freedom in trapped-ion systems have recently been gaining attention as a quantum resource,beyond the role as a mediator for entangling quantum operations on internal degrees of freedom,because of the large available Hilbert *** vibrational modes can be represented as quantum harmonic oscillators and thus offer a Hilbert space with infinite *** we review recent theoretical and experimental progress in the coherent manipulation of the vibrational modes,including bosonic encoding schemes in quantum information,reliable and efficient measurement techniques,and quantum operations that allow various quantum simulations and quantum computation *** describe experiments using the vibrational modes,including the preparation of non-classical states,molecular vibronic sampling,and applications in quantum *** finally discuss the potential prospects and challenges of trapped-ion vibrational-mode quantum information processing.

关键词： quantum computation quantum simulation trapped ions vibrational modes

An Efficient and Spam-Robust Proximity Measure Between Communication Entities

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Journal of Computer Science & Technology 2013年第2期28卷 394-400页

作者： Joo Hyuk Jeon Jihwan Song Jeong Eun Kwon Yoon Joon Lee Man Ho Park Myoung Ho kim Department of Computer Science Korea Advanced Institute of Science and Technology Biz Solution Team SK Telecom Information Technology R&D Center Mobile Communication Convergence Research Team Electronics and Telecommunications Research Institute

Electronic communication service providers are obliged to retain communication data for a certain amount of time by their local laws. The retained communication data or the communication logs are used in various applications such as crime detection, viral marketing, analytical study, and so on. Many of these applications rely on effective techniques for analyzing communication logs. In this paper, we focus on measuring the proximity between two communication entities, which is a fundamental and important step toward further analysis of communication logs, and propose a new proximity measure called ESP （Efficient and Spam-Robust Proximity measure）. Our proposed measure considers only the （graph- theoretically） shortest paths between two entities and gives small values to those between spam-like entities and others. Thus, it is not only computationally efficient but also spam-robust. By conducting several experiments on real and synthetic datasets, we show that our proposed proximity measure is more accurate, computationally efficient and spam-robust than the existing measures in most cases.

关键词： proximity closeness spam electronic communication

Photocatalysts for degradation of dyes in industrial effluents:Opportunities and challenges

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Nano Research 2019年第5期12卷 955-972页

作者： Hassan Anwer Asad Mahmood Jechan Lee Ki-Hyun kim Jae-Woo Park Alex C.K.Yip Department of Civil and Environmental Engineering Hanyang University222 Wangsimni-roSeoul 04763Republic of Korea Department of Environmental and Safety Engineering Ajou UniversitySuwon 16499Republic of Korea Department of Chemical and Process Engineering University of CanterburyChristchurch 8041New Zealand

Discharging dye contaminants into water is a major concern around the *** a variety of methods to treat dye-contaminated water,photocatalytic degradation has gained attention as a tool for treating the colored ***,we review the recent advancements in photocatalysis for dye degradation in industrial effluents by categorizing photocatalyst materials into three *** generation photocatalysts are composed of single-component materials (e.g.,TiO2,ZnO,and CdS),while second generation photocatalysts are composed of multiple components in a suspension (e.g.,WO3/NiWO4,BiOl/ZnTiOa,and C3N4/Ag3VO4).Photocatalysts immobilized on solid substrates are regarded as third generation materials (e.g.,FTO/WO3-ZnO,Steel/TiO2-WO3,and Glass/P-TiO2).Photocatalytic degradation mechanisms,factors affecting the dye degradation,and the lesser-debated uncertainties related to the photocatalysis are also discussed to offer better insights into environmental ***,quantum yields of different photocatalysts are calculated,and a performance evaluation method is proposed to compare photocatalyst systems for dye ***,we discuss the present limitations of photocatalytic dye degradation for field applications and the future of the technology.

关键词： photocatalyst dye wastewater degradation mechanism performance evaluation