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Characteristic evaluation of Al_2O_3/CNTs hybrid materials for micro-electrical discharge machining

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Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 28-32页

作者： Hyun-seok TAK Chang-Seung HA Ho-Jun LEE Hyung-woo LEE Young-Keun JEONG Myung-Chang KANG National Core Research Center for Hybrid Materials Solution Pusan National University Department of Electrical Engineering Pusan National University

The characteristic evaluation of aluminum oxide （A1203）/carbon nanotubes （CNTs） hybrid composites for micro-electrical discharge machining （EDM） was described. Alumina matrix composites reinforced with CNTs were fabricated by a catalytic chemical vapor deposition method. A1203 composites with different CNT concentrations were synthesized. The electrical characteristic of A1203/CNTs composites was examined. These composites were machined by the EDM process according to the various EDM parameters, and the characteristics of machining were analyzed using field emission scanning electron microscope （FESEM）. The electrical conductivity has a increasing tendency as the CNTs content is increased and has a critical point at 5% A1203 （volume fraction）. In the machining accuracy, many tangles of CNT in A1203/CNTs composites cause violent spark. Thus, it causes the poor dimensional accuracy and circularity. The results show that conductivity of the materials and homogeneous distribution of CNTs in the matrix are important factors for micro-EDM of A1203/CNTs hybrid composites.

关键词： A1203/CNTs hybrid materials micro-electrical discharge machining micro-hole electrical conductivity

Development of tenofovir disoproxil fumarate resistance after complete viral suppression in a patient with treatment-na?ve chronic hepatitis B: A case report and review of the literature

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World Journal of Gastroenterology 2018年第17期24卷 1919-1924页

作者： woo Hee Cho Hyun Jae Lee Ki Bae Bang seok Bae Kim Il Han song Department of Internal Medicine Dankook University College of MedicineCheonan 31116South Korea

Tenofovir disoproxil fumarate(TDF) is a potent nucleo-tide analogue that is recommended as first-line therapy for patients with chronic hepatitis B. The results of a longitudinal study of TDF treatment demonstrated no development of resistance. We observed one treatment-na?ve chronic hepatitis B(CHB) patient who developed TDF resistance after complete viral suppression during long-term TDF treatment. A 37-year-old HBe Ag-positive man received TDF 300 mg/d for 43 mo. The hepatitis B virus(HBV) DNA titer was 8 log_(10) copies/m L at baseline and became undetectable at 16 mo after treatment. However, the HBV DNA titer rebounded to 7.5 log_(10) copies/m L at 43 mo after treatment. We performed full sequencing to find mutation sites associated with virologic breakthrough. The results showed 9 mutation sites, most of which had not been well-known as mutation sites. We changed the therapy from tenofovir to entecavir with a regimen of 0.5 mg once daily. After 4 mo, the HBV DNA titer decreased to 267 copies/m L, and the liver enzyme levels were normalized.

关键词： Chronic hepatitis B Tenofovir Resistance Mutation

In-situ formation of MOF derived mesoporous Co3N/amorphous N-doped carbon nanocubes as an efficient electrocatalytic oxygen evolution reaction

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Nano Research 2019年第7期12卷 1605-1611页

作者： Bong Kyun Kang Seo Young Im Jooyoung Lee Sung Hoon Kwag seok Bin Kwon SintayehuNibret Tiruneh Min-Jun Kim Jung Ho Kim woo seok Yang Byungkwon Lim Dae Ho Yoon Nano Materials and Components Research Center Korea Electronics Technology InstituteSeongnam 463-816Republic of Korea School of Advanced Materials Science and Engineering Sungkyunkwan University Suwon 440-746Republic of Korea Advanced Materials & Processing Center Institute for Advanced Engineering (IAE)Yongin 175-28Republic of Korea Australian Institute for Innovative Materials (AIIM) University of WollongongSquires WayNorth Wollongong NSW 2500Australia Department of Advanced Materials Engineering for Information and Electronics Kyung Hee University1732 Deogyeong-daeroGiheung-guYongin-siGyeonggi-do17104Republic of Korea

The suitable materials,metal nitrides,are a promising class of electrocatalyst materials for a highly efficient oxygen evolution reaction (OER) because they exhibit superior intrinsic conductivity and have higher sustainability than oxide-based *** our knowledge,for the first time,we report a designable synthesis of three-dimensional (3D) and mesoporous Co3N@ amorphous N-doped carbon (AN-C) nanocubes (NCs) with well-controlled open-framework structures via monodispersed Co3[Co(CN)6]2 Prussian blue analogue (PBA) NC precursors using in situ nitridation and calcination ***3N@AN-C NCs (2 h) demonstrate better OER activity with a remarkably low Tafel plot (69.6 mV-dec-1),low overpotential of 280 mV at a current density of 10 ***,excellent cycling stability in alkaline electrolytes was exhibited without morphological changes and voltage elevations,superior to most reported hierarchical structures of transition-metal nitride *** presented strategy for synergy effects of metal-organic frameworks (MOFs)-derived transition-metal nitrides-carbon hybrid nanostructures provides prospects for developing high-performance and advanced electrocatalyst materials.

关键词： transition-metal nitride metal organic framework mesoporous oxygen evaluation reaction alkaline water electrolysis

A preliminary study of dietary protein requirement of juvenile marbled flounder (Pseudopleuronectes yokohamae)

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Animal Nutrition 2021年第2期7卷 548-555页

作者： Jeong-Hyeon Cho Seunghyung Lee Bong-Joo Lee Sang-woo Hur Kang-woong Kim Maeng-Hyun son Dong-Jae Yoo Inland Fisheries Research Institute National Institute of Fisheries ScienceGapyeong12453South Korea Department of Marine Bio-materials and Aquaculture Pukyong National UniversityBusan48513South Korea Aquafeed Research Center National Institute of Fisheries SciencePohang37517South Korea Gyeongsangbuk-do Fisheries Resources Institute Yeongdeok36405South Korea Gyeongsangbuk-do Native Fish Business Center Uiseong37366South Korea

An 8-week feeding trial was conducted to determine the optimal dietary protein level for juvenile marbled *** semi-purified test diets were formulated to contain different protein levels(CP)including 42.7%,47.4%,53.3%,58.8%,and 64.5%(dry matter),named as CP42.7,CP47.4,CP53.3,CP58.8,and CP64.5,*** hundred and twenty-five juveniles(6.0±0.1 g)were randomly distributed into 15 tanks(300 L tanks),resulting in 35 fish per tank(n-3 tanks).Fish were fed the test diets 5 times per day until *** CP58.8 resulted in the highest gain in weight and the best efficiency in feed utilization among the tested protein levels(P<0.05).Fish fed the CP58.8 diet showed significantly higher whole-body protein and lipid contents than the fish that were fed the other diets(P<0.05).Fish fed the CP53.3,CP58.8,and CP64.5 diets showed a significantly higher dorsal-muscle lipid content than the fish that were fed the CP42.7 and CP47.4 diets(P<0.05).The one-slope straight broken-line regression analysis on the results of the thermal growth coefficient and feed conversion ratio indicated that the estimated optimum dietary protein level was 58.8%.Taken together,it is suggested that the dietary protein level of 58.8%is optimal for better growth and high efficiency in feed utilization for the juvenile marbled flounder.

关键词： Marbled flounder Pseudopleuronectes yokohamae Protein requirement Growth performance Proximate composition

Influence of protein characteristics and the proportion of gluten on end-use quality in Korean wheat cultivars

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Journal of Integrative Agriculture 2018年第8期17卷 1706-1719页

作者： Seong-woo Cho Chon-Sik Kang Hyeon seok Ko Byung-Kee Baik Kwang-Min Cho Chul Soo Park Department of Crop Science & Biotechnology Chonbuk National University National Institute of Crop Science Rural Development Administration Farm & Agribusiness Management Division Rural Development Administration USDA-ARS CSWQRU Soft Wheat Quality Laboratory Research Center of Bioactive Materials Chonbuk National University

The effects of protein characteristics and the proportion of gluten on end-use quality in 13 Korean wheat cultivars for three years were verified in this study. Year, cultivar, and the interaction between the year and the cultivar influenced protein characteristics, the proportion of gluten except for γ-and ω-gliadin using RP-HPLC(reversed-phase high-performance liquid chromatography), and end-use quality. Protein characteristics and the proportion of gluten in Korean wheat cultivars were between those of Australian standard white(ASW) and hard wheat(AH). Korean wheat cultivars exhibited a higher average α+β gliadin proportion than imported wheat, a γ-gliadin proportion similar to that of dark northern spring wheat, and the same ω-gliadin proportion as AH. They showed a bread-loaf volume intermediate between those of ASW and AH and a texture of cooked noodles similar to that of soft white wheat, but less springiness than imported wheat. The cookie diameter of Korean wheat cultivars was similar to that of hard red winter wheat. There was a correlation between bread-loaf volume and protein characteristics, except for the protein content in Korean wheat cultivars. Springiness and cohesiveness of cooked noodles were not correlated with protein characteristics, while hardness was correlated with the protein content and water absorption of a mixograph. Cookie diameter was negatively correlated with the sodium dodecyl sulfate(SDS) sedimentation volume and water absorption of a mixograph. The end-use quality was not correlated with any proportion of gluten composition. Principal component analysis(PCA) showed that the proportion of gluten was not related to the quality of the bread(both PCs, 81.3%), noodle(77.7%), and cookie(82.4%). PCA explained that Keumkang is suitable for superior bread, while Uri is good for cooked noodles and cookies.

关键词： wheat quality flour quality storage proteins

Characterizing and controlling infrared phonon anomaly of bilayer graphene in optical-electrical force nanoscopy

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Light(Science & Applications) 2023年第12期12卷 2700-2710页

作者： Junghoon Jahng Sunho Lee Seong-Gu Hong Chang Jun Lee Sergey G.Menabde Min seok Jang Dong-Hyun Kim Jangyup son Eun Seong Lee Hyperspectral Nano-imaging Team Korea Research Institute of Standards and ScienceDaejeon 34113Republic of Korea Department of Aerospace Engineering University of Illinois at Urbana-ChampaignUrbanaIL 61801USA Multiscale Mechanical Properties Measurement Team Korea Research Institute of Standards and ScienceDaejeon 34113Republic of Korea School of Mechanical Engineering Chonnam National UniversityGwangju 61186Republic of Korea School of Electrical Engineering Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea Functional Composite Materials Research Center Korea Institute of Science and TechnologyJeonbuk 55324Republic of Korea SKKU Advanced Institute of Nanotechnology Sungkyunkwan UniversitySuwon 16419Republic of Korea Division of Nano&Information Technology KIST SchoolUniversity of Science and TechnologySeoul 02792Republic of Korea

We,for the first time,report the nanoscopic imaging study of anomalous infrared(IR)phonon enhancement of bilayer graphene,originated from the charge imbalance between the top and bottom layers,resulting in the enhancement of E1u mode of bilayer graphene near 0.2 *** modified the multifrequency atomic force microscope platform to combine photo-induced force microscope with electrostatic/Kelvin probe force microscope constituting a novel hybrid nanoscale optical-electrical force imaging *** enables to observe a correlation between the IR response,doping level,and topographic information of the graphene *** the nanoscale spectroscopic image measurements,we demonstrate that the charge imbalance at the graphene interface can be controlled by chemical(doping effect via Redox mechanism)and mechanical(triboelectric effect by the doped cantilever)***,we can also diagnosis the subsurface cracks on the stacked few-layer graphene at nanoscale,by monitoring the strain-induced IR phonon *** approach provides new insights into the development of graphene-based electronic and photonic devices and their potential applications.

关键词： electrical force optical

Optimization of rotor shape for constant torque improvement and radial magnetic force minimization

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Journal of Central South University 2012年第2期19卷 357-364页

作者： CHO Gyu-won woo seok-hyun JI Seung-hun PARK Kyoung-won JANG Ki-bong KIM Gyu-tak School of Mechatronics Changwon National University

The design of notch and barrier was optimized in order to improve the characteristics of constant torque while minimizing the cogging torque that occurs as a result of teeth and slot structure. The barrier was installed in order to minimize the cogging torque and torque ripple by finite element method (FEM) with a reduced barrier width toward the center of magnetic pole. The position and width of notch, which can offset cogging torque, can be calculated with energy distribution of air-gap using Fourier series. The optimized model demonstrates a 60% decrease in the cogging torque, a 75.3% decrease in the torque ripple and a 3% increase in the operating torque when compared with the basic model.

关键词： permanent magnet synchronous motor barrier notch radial magnetic force cogging torque

Effect of Korea red ginseng on cerebral blood flow and superoxide production

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Acta Pharmacologica Sinica 2002年第12期23卷 99-103页

作者： CukSeong KIM,Jin Bong PARK,Kwang-Jin KIM,seok Jong CHANG,Sung-woo RYOO,Byeong Hwa JEON Department of Physiology College of Medicine Chungnam National University Taejon KOREA Department of Physiology College of Medicine Chungnam National University Taejon KOREA Department of Physiology College of Medicine Chungnam National University Taejon KOREA Department of Physiology College of Medicine Seonam University Namwon KOREA Division of Genomics ＆ Proteomics Korea Research Institute of Bioscience and Biotechnology(KRIBB) Yusong Taejon Korea Correspondence to Byeong Hwa JEON MD PhD.Department of Physiology College of Medicine Chungnam National University 6 Munhwa-dong Jung-gu Taejon South Korea 301131

AIM: To investigate the effects of Korea red ginseng (KRG) on the cerebral perfusion rate in the rats and the generation of superoxide anion in the endothelial cells. METHODS: The cerebral perfusion rate was measured using laser-doppler flowmetry before and after the administration of crude saponin (CS) and saponin-free fraction (SFF) of KRG in the anesthetized rats. The superoxide generation was measured by the method based on lucigenin-enhanced chemiluminescence in the cultured endothelial cells. RESULTS: The relative cerebral perfusion rate (rCBF) was significantly increased by the intraperitoneal injection of CS (100 mg/kg) in the rats, but SFF had no effect on the rCBF. Chronic treatment with CS for 7 d significantly inhibited the decrease of forebrain cerebral blood flow induced by clamping both carotid arteries in the rats. Furthermore, CS (0.1 g/L) significantly sup-pressed NADPH-induced superoxide generation in the human umbilical vein endothelial cells (P<0.01). CONCLUSION: The present study d

关键词： Korean red ginseng cerebral blood flow superoxides vascular endothelium

Carbon and nitrogen dynamics in a Pinus densiflora forest with low and high stand densities

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Journal of Plant Ecology 2013年第5期6卷 368-379页

作者： Nam Jin Noh Choonsig Kim Sang Won Bae woo Kyun Lee Tae Kyung Yoon Hiroyuki Muraoka Yowhan son Division of Environmental Science and Ecological Engineering Korea UniversitySeoul 136-713Republic of Korea River Basin Research Center Gifu UniversityGifu 501-1193Japan Department of Forest Resources Gyeongnam National University of Science and TechnologyJinju 660-758Republic of Korea Department of Forest Conservation Korea Forest Research InstituteSeoul 130-712Republic of Korea

Aims Understanding carbon(C)and nitrogen(N)dynamics and their dependence on the stand density of an even-aged,mature forest provides knowledge that is important for forest *** study investigated the differences in ecosystem total C and N storage and flux between a low-density stand(LD)and a high-density stand(HD)and examined the effects of stand density on aboveground net primary productivity(ANPP),total belowground C allocation(TBCA)and net ecosystem production(NEP)in a naturally regenerated,65-to 75-year-old Pinus densiflora *** *** LD(450 trees ha^(−1))and HD(842 trees ha^(−1))were established in an even-aged,mature *** forest in September *** forest had been naturally regenerated following harvesting,and the stand density was naturally maintained without any artificial management such as *** diameter at breast height(DBH≥5.0cm)of all live stems within the stands was measured yearly from 2007 to *** compare C and N storage and fluxes in LD and HD,C and N pools in aboveground and belowground biomass,the forest floor,coarse woody debris(CWD)and soil;soil CO_(2) efflux(R_(S));autotrophic respiration(R_(A));litter production;and soil N availability were ***,ANPP,TBCA and NEP were estimated from plot-based measurement *** Findings Ecosystem C(Mg C ha^(−1))and N(Mg N ha^(−1))storage was,respectively,173.0±7.3(mean±SE)and 4.69±0.30 for LD and 162±11.8 and 4.08±0.18 for *** were no significant differences in C and N storage in the ecosystem components,except for soils,between the two *** contrast,there were significant differences in aboveground ANPP and TBCA between the two stands(P<0.05).Litterfall,biomass increment and R_(S) were major C flux components with values of,respectively,3.89,3.74 and 9.07 Mg C ha^(−1) year^(−1) in LD and 3.15,2.94 and 7.06 Mg C ha^(−1) year^(−1) in ***-based NEP(Mg C ha^(−1) year^(−1))was 4.18 in LD and 5.50 in *** the even-aged,mature P

关键词： aboveground net primary productivity net ecosystem production Japanese red pine stand density total belowground carbon allocation