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Corrosion and optimum corrosion protection potential of friction stir welded 5083-O Al alloy for leisure ship

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中国有色金属学会会刊：英文版 2009年第4期19卷 898-903页

作者： sung-Hyeon park Jong-Shin KIM Min-su HAN Seong-Jong KIM Division of Maritime Transportation System Mokpo Maritime University Korea Register of Shipping Division of Marine Engineering Mokpo Maritime University

Electrochemical tests were undertaken to determine the optimum conditions in seawater for corrosion protection of friction stir-welded 5083-O Al *** trend observations show that the limiting potential that avoids the effects of hydrogen embrittlement is -1.6 V,corresponding to the crossover point between concentration polarization and activation ***,the optimum protection potential is between -1.5 and -0.7 V since the current density at these values is low in the potentiostatic *** a galvanic cell is formed in the seawater,the welds exhibit electrochemically stable *** parts in galvanic tests with various area ratios are stable and have excellent anticorrosion characteristics.

关键词：搅拌摩擦焊接保护电位海水腐蚀铝合金氧铝船舶休闲防腐

An analysis of the radar backscatter from oil-covered sea surfaces using moment method and Monte-Carlo simulation: preliminary results

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Acta Oceanologica Sinica 2013年第1期32卷 59-67页

作者： YANG Chan-su park Seong-Min OH Yisok OUCHI Kazuo Korea Ocean Satellite Center Korea Institute of Ocean Science & Technology (KIOST) Marine Environmental System Science University of Science and Technology ISR R&D Laboratory LIG Nex1 Company Department of Electronics Information and Communication Engineering Hongik University Department of Computer Science School of Electrical and Computer Engineering National Defense Academy

An analysis of the radar backscattering from the ocean surface covered by oil spill is presented using a mi- crowave scattering model and Monte-Carlo simulation. In the analysis, a one-dimensional rough sea sur- face is numerically generated with an ocean waveheight spectrum for a given wind velocity. A two-layered medium is then generated by adding a thin oil layer on the simulated rough sea surface. The electric fields backscattered from the sea surface with two-layered medium are computed with the method of moments （MoM）, and the backscattering coefficients are statistically obtained with N independent samples for each oil-spilled surface using the Monte-Carlo technique for various conditions of surface roughness, oil-layer thickness, frequency, polarization and incidence angle. The numerical simulation results are compared with theoretical models for clean sea surfaces and SAR images of an off-spilled sea surface caused by the Hebei （Hebei province, China） Spirit oil tanker in 2007. Further, conditions for better oil spill extraction are sought by the numerical simulation on the effects of wind speed and oil-layer thickness at different inci- dence angles on the backscattering coefficients.

关键词： method of moments Monte-Carlo technique oil spills backscattering coefficient

Electrostabilized homogeneous dispersion of boron nitride nanotubes in wide-range of solvents achieved by surface polarity modulation through pyridine attachment

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Nano Research 2020年第2期13卷 344-352页

作者： Mi Se Chang Min-sun Jang Sangsun Yang Jihun Yu Taehoon Kim Sedong Kim Hyomin jeong Chong Rae park Jae Won jeong Powder/Ceramic Research Division Korea Institute of Materials Science797 Changwondae-roSeongsan.guChangwon 51508Republic of Korea Research Institute of Advanced Materials and Department of Materials Science and Engineering Seoul National University Seoul 08826Republic of Korea Composites Research Division Korea Institute of Materials Science797 Changwondae-roSeongsan-guChangwon 51508Republic of Korea Dept.of Energy and Mech.Eng Gyeongsang National UniversityCheondaegukchi-Gil 38Tongyeong 53064Republic of Korea

Boron nitride nanotubes(BNNTs)show exceptional physical properties including high mechanical strength and thermal conductivity;however,their applications have been restricted due to limited dispersibility in processing ***,a novel BNNT dispersion method with exceptional dispersibility in a wide range of solvents has been demonstrated by surtace polarity modulation through short-molecule pyridine *** atoms in pyridine are selectively bonded to electron-deficient boron atoms of the BNNT surface through Lewis acid-base reaction,which changes the surface polarity of BNNTs from neutral to ***-dispersing pyridine-attached BNNTs(Py-BNNTs)create a thick and stable electronic double layer(EDL),resulting in uniform dispersion of BNNTs in solvents with an exceptional solubility parameter range of 18.5-48 MPa^1/*** uniform dispersion of BNNTs is maintained even after the mixing with diverse ***,composites incorporating uniformly-distributed BNNTs have been realized,and extraordinary property enhancements have been *** thermal conductivity of 20 wt.%Py-BNNT/epoxy composite has been significantly improved by 69.6%and the tensile strength of 2 wt.%Py-BNNT/PVA has been dramatically improved by 75.3%.Our work demonstrates a simple and facile route to dispersing BNNTs in diverse solvents,consequently leading to selective utlization of BNNT dispersed solvents in various application fields.

关键词： boron nitride nanotube one-dimensional nanomaterials surface polarity modulation electrostabilization boron nitride nanotube composite

Primary endoscopic approximation suture under cap-assisted endoscopy of an ERCP-induced duodenal perforation

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World Journal of Gastroenterology 2010年第18期16卷 2305-2310页

作者： Tae Hoon Lee Byoung Wook Bang Jee In jeong Hyung Gil Kim Seok jeong Seon Mee park Don Haeng Lee Sang-Heum park sun-Joo Kim Division of Gastroenterology Department of Internal MedicineSoon Chun Hyang University College of MedicineCheonan Hospital Division of Gastroenterology Department of Internal MedicineInha University School of Medicine Division of Gastroenterology Department of Internal MedicineChungbuk National University College of Medicine

Duodenal perforation during endoscopic retrograde cholangiopancreatography(ERCP) is a rare complication,but it has a relatively high mortality *** diagnosis and prompt management are key factors for the successful treatment of ERCP-related *** management of perforation can initially be conservative in cases resulting from sphincterotomy or guide wire ***,the current standard treatment for duodenal free wall perforation is surgical ***,several case reports of endoscopic closure techniques using endoclips,endoloops,or fully covered metal stents have been *** describe four cases of iatrogenic duodenal bulb or lateral wall perforation caused by the scope tip that occurred during ERCP in tertiary referral *** the cases were simply managed by endoclips under transparent capassisted *** on the available evidence and our experience,endoscopic closure was a safe and feasible method even for duodenoscope-induced *** results suggest that endoscopists may be more willing to use this treatment.

关键词： Duodenal perforation Endoscopic retrograde cholangiopancreatography Endoscopic therapy Endoclip

Optimization of thermoelectric properties of n-type Bi_2(Te,Se)_3 with optimizing ball milling time

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Rare Metals 2018年第4期37卷 351-359页

作者： Ji-Hee Son Min-Wook Oh Bong-Seo Kim su-Dong park Thermoelectric Conversion Research Center Korea Electrotechnology Research Institute Department of Materials Science and Engineering Hanbat National University

The thermoelectric properties at elevated temperature were investigated for n-type Bi2（Te,Se）3 which is obtained from ball milling processed powder with various milling times. Electrical properties such as electrical resistivity and Seebeck coefficient are clearly dependent on milling time, in which the carrier concentration is attributed to the change of the electrical properties. The concentrations of the defects are also varied with the ball milling time, which is the origin of the carrier concentration variation. Even though finer grain sizes are obtained after the long ball milling time, the temperature dependence of the thermal conductivity is not solely understood with the grain size, whereas the electrical contribution to the thermal conductivity should be also considered. The highest figure of merit value of ZT = 0.83 is achieved at 373 K for the optimized samples, in which ball milling time is 10 h. The obtained ZT value is 48% improvement over that of the 0.5-h sample at 373 K.

关键词： Thermoelectric properties Ball milling Bi2Te3 Seebeck coefficient Grain size Thermalconductivity

Differentiation of hepatocellular carcinoma from its variousmimickers in liver magnetic resonance imaging:What arethe tips when using hepatocyte-specific agents?

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World Journal of Gastroenterology 2016年第1期22卷 284-299页

作者： Yang Shin park Chang Hee Lee jeong Woo Kim Sora Shin Cheol Min park Department of Radiology Korea University Guro HospitalKorea University College of MedicineSeoul 152-703South Korea Korea University College of Medicine Anam-dong 5-gaSeongbuk-GuSeoul 136-701South Korea

Hepatocellular carcinoma is the most common primary hepatic malignant *** widespread use of liver imaging,various cirrhosis-related nodules are frequently detected in patients with chronic liver disease,while diverse hypervascular hepatic lesions are incidentally detected but undiagnosed on dynamic computed tomography and magnetic resonance imaging(MRI).However,use of hepatocyte-specific MR contrast agents with combined perfusion and hepatocyte-selective properties have improved diagnostic performance in detection and characterization of focal liver ***,the enhancement patterns observed during dynamic phases using hepatocyte-specific agents may be different from those observed during MRI using conventional extracellular fluid agents,leading to confusion in ***,we discuss useful tips for the differentiation of hepatocellular carcinoma from similar lesions in patients with and without chronic liver disease using liver MRI with hepatocyte-specific agents.

关键词： Hepatocellular carcinoma Gadoxetic acid Magnetic resonance imaging Liver cirrhosis

Recent application of biochar on the catalytic biorefinery and environmental processes

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Chinese Chemical Letters 2019年第12期30卷 2147-2150页

作者： Hyung Won Lee Heejin Lee Young-Min Kim Rae-su park Young-Kwon park School of Environmental Engineering University of SeoulSeoul 02504Republic of Korea Department of Environmental Engineering Daegu UniversityGyeongsan 38452Republic of Korea Department of Bioenvironmental&Chemical Engineering Chosun College of Science&TechnologyGwangju 61453Republic of Korea

Lignocellulosic biomass is an abundant and environment-friendly source for renewable energy *** value and application of biochar,which is obtained from the thermochemical conversion of biomass,is increasing rapidly because of its high carbon content and *** property of biochar,such as surface area,porosity,and number of functional groups,can be improved by controlling the conditions of biomass conversion,biochar activation,and functionalization *** production and activation of biochar as well as its potential use for soil remediation,pollutant adsorption,and biorefinery have been reviewed extensively over recent *** paper provides a conceptual approach for biochar production and activation together with its application as a catalyst for biorefineries and the removal of environmental contaminants.

关键词： Biomass Thermochemical conversion Biochar Activation Catalyst

New para-magnetic(CoFeNi)(50)(CrMo)(50-x)(CB)x(x=20,25,30)non-equiatomic high entropy metallic glasses with wide supercooled liquid region and excellent mechanical properties

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Journal of Materials Science & Technology 2020年第8期36卷 135-143页

作者： jeong Tae Kim sung Hwan Hong Jin Man park Jürgen Eckert Ki Buem Kim Erich Schmid Institute of Materials Science Austrian Academy of Sciences(ÖAW)Jahnstrae 128700LeobenAustria Hybrid Materials Center(HMC) Department of Nanotechnology and Advanced Materials EngineeringSejong University209Neungdong-roGwangjin-guSeoul143-747Republic of Korea Global Technology Center(GTC) Samsung Electronics Co.Ltd129 Samsung-roYeongtong-guSuwonsiGyeonggi-do443-742Republic of Korea Department of Materials Science Chair of Materials PhysicsMontanuniversität LeobenJahnstraße 128700LeobenAustria

In this study,high entropy metallic glasses(HEMGs)were developed through a combination of concepts for designing metallic glasses(main element+transition metal+metalloid element)and high-entropy alloys(more than five elements,each element having an atomic concentration between 5 at.%and 35 at.%).The developed metallic glass alloys are composed of Co-Fe-Ni main elements,transition metals(Cr,Mo)and metalloid elements(C,B).Moreover,the present work reports the thermal,mechanical and magnetic properties of(CoFeNi)(50)(CrMo)(50-x)(CB)x alloys with x=20,25,*** developed as-spun HEMGs exhibit typical paramagnetic properties even for a high amount of ferromagnetic elements(Co,Fe,and Ni)and have high elastic modulus(103–160 GPa)and hardness(14–27 GPa),thus possessing mechanical properties similar to well-known Co-based metallic glasses(Co-Cr-Mo-C-B system).In addition,some of the bulk samples prepared with a diameter of 2 mm form bulk metallic glasses with a high compressive strength around 3.5 *** mechanisms determining the stability of the supercooled liquid,as well as the paramagnetic and mechanical properties for the developed non-equiatomic HEMGs,are discussed.

关键词： Metallic glasses Paramagnetism High entropy alloys Phase stability

Long Short-Term Memory Recurrent Neural Network-Based Acoustic Model Using Connectionist Temporal Classification on a Large-Scale Training Corpus

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China Communications 2017年第9期14卷 23-31页

作者： Donghyun Lee Minkyu Lim Hosung park Yoseb Kang jeong-Sik park Gil-Jin Jang Ji-Hwan Kim Department of Computer Science and Engineering Sogang University Department of Information and Communication Engineering Yeungnam University School of Electronics Engineering Kyungpook National University

A Long Short-Term Memory(LSTM) Recurrent Neural Network(RNN) has driven tremendous improvements on an acoustic model based on Gaussian Mixture Model(GMM). However, these models based on a hybrid method require a forced aligned Hidden Markov Model(HMM) state sequence obtained from the GMM-based acoustic model. Therefore, it requires a long computation time for training both the GMM-based acoustic model and a deep learning-based acoustic model. In order to solve this problem, an acoustic model using CTC algorithm is proposed. CTC algorithm does not require the GMM-based acoustic model because it does not use the forced aligned HMM state sequence. However, previous works on a LSTM RNN-based acoustic model using CTC used a small-scale training corpus. In this paper, the LSTM RNN-based acoustic model using CTC is trained on a large-scale training corpus and its performance is evaluated. The implemented acoustic model has a performance of 6.18% and 15.01% in terms of Word Error Rate(WER) for clean speech and noisy speech, respectively. This is similar to a performance of the acoustic model based on the hybrid method.

关键词： acoustic model connectionisttemporal classification large-scale trainingcorpus long short-term memory recurrentneural network