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Journal of Materials Science & Technology 2023年第16期147卷 77-90页

作者： Dhananjay Mishra Seungyeob kim Niraj Kumar Mokurala Krishnaiah Sung hun Jin Department of Electronic Engineering Incheon National UniversityAcademy-ro 119Yeongsu-guIncheon 22012The Republic of Korea

With the surge of demand for instant high power in miniaturized electronic and mechanical systems,supercapacitors(SCs)are considered as one of the viable candidates to fulfill the ***,long-term resilience and superior energy density associated with self-discharge in SCs are obviously critical,but securing electrode materials,which can meet both benefits of SCs and persist charged potential for a comparatively prolonged duration,are still ***,hierarchically refined nickel-sulfide heterostructure(CuO-NS)on CuO(CO)scaffold is achieved through optimized film formation,exhibiting a threefold improvement in the essential electrochemical characteristics and outstanding capacitance retention(∼5%loss).Self-discharge behavior and its mechanism are systematically investigated via morphological control and nanostructural ***,significant mitigation of self-discharge owing to an increase in surface area and refined nanostructure is ***,CuO-NS2(20 cycle overcoating)based SC can retain over 60%of the charged potential for a complete voltage holding and a self-discharge test for 16 *** appealing demonstration of wireless power transmission in burst mode is demonstrated for secure digital(SD)card data writing,powered by SCs,which substantiates that it can be readily leveraged in power management *** enables us to realize one of the envisioned applications soon.

关键词： CuO-Ni_(3)S_(2)hierarchical heterostructure Voltage holding test Supercapacitor Self-discharge mitigation Wireless power transmission

Effect of carbon on microstructure of CrAlC_xN_(1-x) coatings by hybrid coating system

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 78-82页

作者： Sung-Kyu AHN Se-hun KWON Kwang-Ho kim National Core Research Center for Hybrid Materials Solution Pusan National University School of Materials Science and Engineering Pusan National University

A systematic investigation of the microstructure of CrA1CxN1-x coatings as a function of carbon contents was conducted. Quaternary CrA1CxN1-x coatings were deposited on Si wafers by a hybrid coating system combining an arc-ion plating technique and a DC reactive magnetron sputtering technique using Cr and AI targets in the Ar/N2/CH4 gaseous mixture. The effect of carbon content on microstructure of CrA1C^N~ x coatings was investigated with instrumental analyses of X-ray diffraction, X-ray photoelectron, and high-resolution transmission electron microscopy. The results show that the carbon content of CrA1CxN1-x coatings linearly increases with increasing CH4/（CH4/N2） gas flow rate ratio. The surface roughness of the CrA1CxN1-x coating layer decreases with the increase of carbon content.

关键词： CrA1C,N1-x, coating nanocomposite microstructure hybrid coating system

Graphene-based saturable absorber and mode-locked laser behaviors under gamma-ray radiation

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Photonics Research 2019年第7期7卷 57-62页

作者： Dohyun kim nam hun Park Hyunju Lee Jaegoan Lee Dong-Il Yeom Jungwon kim School of Mechanical and Aerospace Engineering Korea Advanced Institute of Science and Technology (KAIST)Daejeon 34141South Korea Department of Energy Systems Research & Department of Physics Ajou UniversitySuwon 16499South Korea

We investigate optical and electrical behaviors of a graphene saturable absorber (SA) and mode-locking performance of a graphene-SA-based mode-locked Er fiber laser in gamma-ray radiation. When irradiated up to 4.8 kGy at ~ 100 Gy/hr dose rate, the overall nonlinear transmittance in transverse electric mode was increased, while maintaining modulation depth to >10%. The corresponding *** loss was reduced at a 1.2-dB/kGy rate. In the electrical properties, the charge carrier mobility was reduced, and the Dirac voltage shift was increased to positive under gamma-ray radiation. The radiation-induced optical and electrical changes turned out to be almost recovered after a few days. In addition, we confirmed that the graphene-SA-based laser showed stable CW mode-locking operation while the inserted graphene SA was irradiated for 2-kGy at a 45-Gy/hr dose rate, which corresponds to >40 years of operation in low Earth orbit *** the best of our knowledge, this is the first evaluation of graphene SAs and graphene-SA-based mode-locked lasers in gamma-ray radiation, and the measured results confirm the high potential of graphene SAs and graphene-SA-based lasers in various outer-space environments as well as other radiation environments, including particle accelerators and radiationbased medical instruments.

关键词： absorber modelocked laser accelerators

Appetite for Natech Risk Information in Japan:Understanding Citizens'Communicative Behavior Towards Risk Information Disclosure Around Osaka Bay

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International Journal of Disaster Risk Science 2022年第3期13卷 372-390页

作者： Dimitrios Tzioutzios Jeong-nam kim Ana Maria Cruz Department of Urban Management Graduate School of EngineeringKyoto UniversityKyoto615-8540Japan Gaylord College of Journalism and Mass Communication University of OklahomaNormanOK73019USA Disaster Prevention Research Institute Kyoto UniversityKyoto611-0011Japan

Effective risk communication is essential for disaster risk *** from empowering communities to make informed risk choices,risk information disclosure can also drastically enhance their disaster preparedness,especially concerning conjoint scenarios of technological and natural hazards(Natech).A fundamental precondition is the actual demand for such *** study ventures to assess whether residents around Osaka Bay have this demand,or"appetite,"for risk information disclosure,as well as to understand their communicative behavior and perceived challenges in the Japanese context through the prism of the Situational Theory of Problem *** test this framework under realistic conditions,data were collected through a household questionnaire survey from two urban areas near industrial complexes in Osaka *** results show that identifying Natech risk information deficiency as a problem was not a statistically significant predictor for individuals'motivation to ***,their motivation increased as their perceived personal involvement with the situation rose,while the perceived obstacles in doing something about it exerted a negative influence on their ***'motivation intensified their communicative actions to solve this *** segmentation underscored the elevated public perceptions concerning the issue of risk information deficiency in nearly nine out of ten *** findings indicate a strong community appetite for chemical and Natech risk information,which subsequently led to high situational motivation to engage in communicative action,particularly information *** management policy is suggested to focus on introducing chemical risk information disclosure regulatory initiatives to encourage citizen engagement.

关键词： Japan Natech risk information Participatory risk management Risk communication Situational Theory of Problem Solving(STOPS)

Examining global warming factors using self-organizing map and Granger causality network:a case from South Korea

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Ecological Processes 2023年第1期12卷 140-150页

作者： Thakur Dhakal Tae-Su kim Do-hun Lee Gab-Sue Jang Department of Life Science Yeungnam UniversityGyeongsan 38541Republic of Korea National Institute of Ecology Seocheon 33657Republic of Korea

Background Understanding and patterning the possible causal variables of global warming is attributed to the development of effective prevention and mitigation strategies for climate ***,we aimed to pattern and visualize the possible causal variables of global warming and measure the causality between *** We patterned and visualized the time series(103 years,from 1918 to 2020)of global surface temperature(GTemp)data with the gross domestic product(GDP)per capita,human population(Pop),and carbon dioxide(CO_(2))emissions of South Korea using a self-organizing map(SOM)and examined the causable local feature of global warming using the Granger causality(GC)*** time-series data were trained and mapped in 4×4 SOM grids,and causality networks between variables were examined using multivariate Granger test *** SOM patterned 103 years of data,and a dominant cluster contained continuous time-series data from 2007 to ***,the CO_(2)emissions of South Korea were obtained as a predictable unidirectional causal variable for GTemp from GC *** on data from the past 34 years,significant causality(p-value=0.01)was observed with the integrated effect of Pop,GDP,and CO_(2)on *** This study patterned the time-series data using SOM and examined the causal relationship between variables using the GC *** study framework could be used as a reference by future scholars,ecologists,and the United Nations Sustainable Development Goals.

关键词： Climate change Ecology Self-organizing map Sustainable development goal Greenhouse gas

Progress in light-to-frequency conversion circuits based on low dimensional semiconductors

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Nano Research 2021年第9期14卷 2938-2964页

作者： Seung Gi Seo Seung Yeob kim Jinheon Jeong Sung hun Jin Department of Electronic Engineering Incheon National UniversityAcademy-ro 119Yeongsu-guIncheon 22012Republic of Korea

As the scaling down of Si devices in the range less than few nm has been expedited up to a physical limit of Si,low dimensional materials have been regarded as one of next generation *** a variety of applications,studies on photodetectors have been actively investigated with their novel optical properties as well as astonishing electrical ***,most of research has focused on single device-type photodetector(i.e.,photo-diode or photo-transistor).Contrary to common photodetector,light-to-frequency circuits(LFCs)are based on frequency reading with photosensitive ring oscillators,which has better noise immunity and reduced system complexity,thus,can be utilized to novel application even in internet of things(loT)and bio&medical *** this review,low dimensional materials based circuit level photodetectors,which are core elements as the form of either inverters or ring oscillators for demonstration of LFCs,are *** with the introduction of low dimensional materials and their optical properties for optoelectronics,a fundamental concept for LFCs is specifically ***,research progress on low dimensional material based photosensitive inverters is addressed according to the types of ***,as one of practical method for the improvement of photodetector performance,molecular doping technology is ***,complete system of LFCs and its digitization for demonstration of production level,and potential application in the respective four aspects,(i)medical SpO_(2) detection,(ii)biological fluidic system,(iii)auto-lighting in agriculture,and(iv)optical feedback and sensing systems,are presented as systematic way to address the envisioned practical applications for the future displays including virtual reality and augmented reality,and *** a remark,LFCs based on low dimensional semiconductors are expected to be one of core components in trillion’s sensor area.

关键词： photodetector light-to-frequency conversion circuit transition metal dichalcogenide carbon nanotube

Newly developed autoimmune cholangitis without relapse of autoimmune pancreatitis after discontinuing prednisolone

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World Journal of Gastroenterology 2012年第41期18卷 5990-5993页

作者： Ji hun kim Jae Hyuck Chang Sung Min nam Mi Jeong Lee Il Ho Maeng Jin Young Park Yun Sun Im Tae Ho kim Chang Whan kim Sok Won Han Department of Internal Medicine College of MedicineThe Catholic University of KoreaSeoul 137-701South Korea

A 57-year-old man presented with a 2-wk history of painless jaundice and weight Iossl He had a large ill- defined enhancing mass-like lesion in the uncinate pro- cess of the pancreas with stricture of the distal common bile duct. Aspiration cytology of the pancreatic mass demonstrated inflammatory cells without evidence of malignancy. Total serum immunoglobulin G level was slightly elevated, but IgG4 level was normal. After the 2-wk 40 mg prednisolone trial, the patient＇s symptoms and bilirubin level improved significantly. A follow-up computed tomography （CT） scan showed a dramatic resolution of the pancreatic lesion. A low dose steroid was continued. After six months he self-discontinued prednisolone for 3 wk, and was presented with jaundice again. ACT scan showed newly developed intrahepatic biliary dilatation and marked concentric wall thickening of the common hepatic duct and the proximal common bile duct without pancreatic aggravation. The patient＇ s IgG4 level was elevated to 2.51 g/L. Prednisolone was started again, after which his serum bilirubin level became normal and the thickening of the bile duct was resolved. This case suggests that autoimmune pancre- atitis can progress to other organs that are not involved at the initial diagnosis, even with sustained pancreatic remission.

关键词： Autoimmune disease Pancreatitis Cholan-gitis Prednisolone

Spatio-temporal variability in sea surface wind stress near and off the east coast of Korea

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Acta Oceanologica Sinica 2005年第1期24卷 107-114页

作者： nam SungHyun kim Young Ho PARK Kyung-Ae kim Kuh Ocean Laboratory/RIO School of Earth and Environmental Sciences Seoul National University Seoul 151-742 KoreaOcean Laboratory/RIO School of Earth and Environmental Sciences Seoul National University Seoul 151-742 KoreaOcean Laboratory/RIO School of Earth and Environmental Sciences Seoul National University Seoul 151-742 KoreaOcean Laboratory/RIO School of Earth and Environmental Sciences Seoul National University Seoul 151-742 Korea

Sea surface wind stress variabilities near and off the east coast of Korea, are examined using 7 kinds of wind datasets from measurements at 2 coastal (land) stations and 2 ocean buoys,satellite scatterometer (QuikSCAT), and global reanalyzed products (ECMWF,NOGAPS,and NCEP/NCAR). Temporal variabilities are analyzed at 3 frequency bands; synoptic (2-20 d), intra-seasonal (20-90 d),and seasonal (>90 d).Synoptic and intra-seasonal variations are predominant near and off the Donghae City due to the passage of the mesoscale weather system. Seasonal variation is caused by southeastward wind stress during Asian winter monsoon. The sea surface wind stress from reanalyzed *** and KMA-B measurements off the coast show good agreement in the magnitude and direction,which are strongly aligned with the alongshore *** the land-based sites,wind stresses are much weaker by factors of 3-10 due to the mountainous landmass on the east parts of Korea *** first EOF modes(67%-70%) of wind stresses from reanalyzed and QuikSCAT data have similar structures of the strong southeastward wind stress in winter along the coast but show different curl structures at scales less than 200 km due to the orographic *** second EOF modes (23%-25%) show southwestward wind stress in every September along the east coast of the North Korea

关键词： sea surface wind stress spatio-temporal variability monsoon seasonal intra-seasonal synoptic band orographic effect

Ni, Co-double hydroxide wire structures with controllable voids for electrodes of energy-storage devices

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Journal of Materials Science & Technology 2020年第20期52卷 126-135页

作者： Jin Kyu kim Chang Soo Lee Jae hun Lee Jung Tae Park Jong Hak kim Department of Chemical and Biomolecular Engineering Yonsei University50 Yonsei-roSeodaemun-guSeoul 03722Republic of Korea Department of Chemical Engineering Konkuk University120 Neungdong-roGwangjin-guSeoul 05029Republic of Korea

We re port the facile synthesis of Ni,Co-double hydroxide wire(NCHW)-based electrodes directly grown on a conductive substrate via a hydrothermal *** NCHW nanostructures were grown on Ni foam,and the growth was controlled using different compositions of solvents(ethanol and water).With increasing volume ratio of ethanol to water,the density of the wires decreased,and the spatial voids between the wires *** formation of large empty spaces improved the electrochemical performance because the exposure of a large surface area of the structure to the electrolyte resulted in a large number of active sites and facile electrolyte penetration into the *** different NCHW structures were ascribed to the pivotal role of the solvent in the urea hydrolysis;the solvent triggered the formation of hydroxides during the hydrothermal *** electrochemical performance of the NCHW electrodes was investigated via galvanostatic charge/discha rge tests,cyclic voltammetry,and electrochemical impedance *** highest specific capacitance was 1694.7 m F/cm^2 at 2 mA/cm^2,with excellent capacitance retention of 81.5% after 5000 *** superior electrochemical performance of the NCHW electrodes is attributed to the large number of active sites and facile electrolyte diffusion into the structure,due to the well-organized structure with an optimized density of nanowires and large voids between the wires.

关键词： Ni,Co-double hydroxide Nanowire Electrode Energy-storage device Supercapacitor

Nondestructive Skeletal Imaging of Hyla suweonensis Using Micro-Computed Tomography

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Asian Herpetological Research 2017年第4期18卷 235-243页

作者： Eunbin kim Hacheol SUNG Donghyun LEE Geunjoong kim Dongha nam Etmgsam kim School of Biological Sciences and Biotechnology Chonnam National University 77 Yongbong-ro Bukgu Gwangju 61186 South Korea2 u 61186 South Korea

We successfully obtained 3D skeletal images of Hyla suweonensis, employing a nondestructive method by applying appropriate anesthesia and limiting the radiation dose. H. suweonensis is a tree frog endemic to Korea and is on the list of endangered species. Previous studies have employed caliper-based measurements and two-dimensional （2D） X-ray imaging for anatomical analyses of the skeletal system or bone types of H. suweonensis. In this work we reconstructed three-dimensional （3D） skeletal images of H. suweonensis, utilizing a nondestructive micro-computed tomography （micro-CT） with a short scan and low radiation dose （i.e. 4 min and 0.16 Gy）. Importantly, our approach can be applied to the imaging of 3D skeletal systems of other endangered frog species, allowing both versatile and high contrast images of anatomical structures without causing any significant damages to the living animal.

关键词： Hyla suweonensis Micro-computed tomography 3D skeletal structure Nondestructive imaging,Endangered species Radiation dose.