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World Journal of Gastroenterology 2014年第46期20卷 17558-17567页

作者： Hee Sun Park young Jun kim Mi Hye Yu Won Hyeok Choe Sung il Jung Hae Jeong Jeon Department of Radiology Konkuk University School of MedicineSeoul 143-729South Korea Digestive Disease Center Konkuk University School of MedicineSeoul 143-729South Korea

AIM: To evaluate the feasibility of 3-Tesla magnetic resonance elastography (MRE) for hepatic fibrosis and to compare that with diffusion-weighted imaging (DWI) and gadoxetic acid-enhanced magnetic resonance (MR) imag... 详细信息

关键词： Magnetic resonance elastography Hepatic fibrosis Diffusion weighted imaging Gadoxetic acid enhanced magnetic resonance imaging Serum markers

Grain size dependence of flow stress in ECAPed Ti with constant texture

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中国有色金属学会会刊：英文版 2012年第S3期22卷 673-677页

作者： Chang-young HYUN Ho-Kyung kim Department of Materials Science and Engineering Seoul National University of Science and Technology Department of Automotive Engineering Seoul National University of Science and Technology

The effect of grain size on the flow stress in an ECAPed Ti with a constant texture was investigated,assuming that 2,4,5 and 6 passes microstructures have a similar *** average size of recrystallized grains decreased to 0.5 μm,0.4 μm,and 0.3 μm with respect to the ECAP pass number of 2,4,and 6,*** ultimate tensile strength (UTS) and yield strength (YS) increase with an increase in the number of *** UTS and YS of the 6 passes ECAPed sample were found to be 740.2 MPa and 580.3 MPa,*** equation for the flow stress of an ECAPed Ti with a constant texture as a function of the strain and grain size was derived for the ECAPed *** following equation was finally obtained:σ(ε)=103.9+1825ε-9.6ε1/2·d-1/2+8.3d-1/2.

关键词： Ti mechanical properties grain size flow stress equal channel angular pressing

Acoustic Nonlinearity of a Laser-Generated Surface Wave in a Plastically Deformed Aluminum Alloy

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Chinese Physics Letters 2012年第12期29卷 39-43页

作者： kim Chung-Seok JHANG Kyung-young Metallurgy and Materials Engineering Chosun UniversitySeosuk-dongGwangju501-759South Korea Mechanical Engineering Hanyang UniversityHangdang-dongSeongdong-guSeoul133-791South Korea

The acoustic nonlinearity of surface waves is studied to evaluate plastic deformation in aluminum alloys.A narrow-band surface wave is successfully generated by a pulsed Nd-YAG laser system consisting of a beam expander and a slit *** degrees of tensile deformation are induced by interrupting the tensile tests so as to obtain aluminum specimens with different degrees of plastic *** normalized acoustic nonlinearity increases as a function of tensile *** experimental results show that the acoustic nonlinearity of a laser-generated surface wave has a good correlation with the level of tensile deformation and has a potential to evaluate microdamage induced by dislocation microplasticity.

关键词： deformation nonlinearity Deform

The Role of Relative Spinal Motion during Feline Galloping for Speed Performance

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Journal of Bionic Engineering 2014年第4期11卷 517-528页

作者： young Kook kim Jongwon Park Byungho Yoon Kyung-Soo kim Soohyun kim Robotics Program Korea Advanced Institute of Science and Technology (KAIST) Daejeon 305-701 Republic of Korea Department of Mechanical Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon 305-701 Republic of Korea

Felines use their spinal column to increase their running speed at rapid locomotion performance. However, its motion profile behavior during fast gait locomotion has little attention. The goal of this study is to examine the relative spinal motion profile during two different galloping gait speeds. To understand this dynamic behavior trend, a dynamic motion of the feline animal （Felis catus domestica） was measured and analyzed by motion capture devices. Based on the experiments at two different galloping gaits, we observed a significant increase in speed （from 3.2 m.s-1 to 4.33 m.s-1） during the relative motion profile synchronization between the spinal （range： 118.86~ to 168.00~） and pelvic segments （range： 46.35~ to 91.13~） during the hindlimb stance phase （time interval： 0.495 s to 0.600 s）. Based on this discovery, the relative angular speed profile was applied to understand the possibility that the role of the relative motion match during high speed locomotion generates bigger ground reaction force.

关键词： feline galloping galloping gait pattern relative spinal motion speed performance phase match

Effect of pulse time on surface characteristics and corrosion resistance during pulse electrochemical polishing

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中国有色金属学会会刊：英文版 2012年第S3期22卷 876-880页

作者： young-Bin kim Jeong-Woo PARK Department of Advanced Parts and Materials Engineering Chosun University Department of Mechanical Design Engineering Chosun University

Pulse electrochemical polishing (PECP) was used to improve the mechanical properties,such as surface roughness and corrosion resistance,of conductive metallic *** can provide a smooth,bright,reflective,and deburred surface that exhibits superior corrosion *** this work,stainless steel was used as the anode,and copper was used as the cathode due to their low electrical *** surface roughness of the PECP sample was measured by atomic force microscopy (AFM).A scanning electron microscope (SEM) was used to observe surface characteristics,and an Auger electron spectroscope (AES) was used to analyze the metallurgical composition and thickness of the passive *** aim of this research was to compare the corrosion resistance rates of the unprocessed and PECP-processed stainless steel.

关键词： stainless stell pulse electrochemical polishing corrosion resistance

Transparent Supercapacitors: From Optical Theories to Optoelectronics Applications

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Energy & Environmental Materials 2020年第3期3卷 265-285页

作者： Sang-Woo kim Sang-young Lee Department of Energy Engineering School of Energy and Chemical EngineeringUlsan National Institute of Science and Technology(UNIST)Ulsan 689-798Korea

The ever-increasing demand for smart optoelectronics spurs the relentless pursuit of transparent wireless devices as a game-changing technology that can provide unseen visual information behind the *** enable successful operation of the transparent wireless devices,their power sources should be highly transparent in addition to acquiring reliable electrochemical *** various transparent power sources,supercapacitors(SCs)have been extensively investigated as a promising candidate due to their exceptional cyclability,power capability,material diversity,and scalable/low-cost ***,we describe current status and challenges of transparent SCs,with a focus on their core materials,performance advancements,and integration with application devices.A special attention is devoted to transparent conductive electrodes(TCEs)which act as a keyenabling component in the transparent *** on fundamental understanding of optical theories and operating principles of transparent materials,we comprehensively discuss materials chemistry,structural design,and fabrication techniques of *** addition,noteworthy progresses of transparent SCs are briefly overviewed in terms of their architectural design,opto-electrochemical performance,flexibility,form factors,and integration compatibility with transparent flexible/wearable devices of ***,development direction and outlook of transparent SCs are explored along with their viable roles in future application fields.

关键词： energy storage flexibility optoelectronics transparent conductive electrodes transparent supercapacitors

Suppression of gold nanoparticle agglomeration and its separation via nylon membranes

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Chinese Journal of Chemical Engineering 2017年第7期25卷 931-937页

作者： Ayyavoo Jayalakshmi In-Chul kim young-Nam Kwon School of Urban and Environmental Engineering Ulsan National Institute of Sdence and TechnologyUlsan 689-798Korea KIST-UNIST UIsan Center for Convergent Materials UNIST(Ulsan National Institute of Science and Technology)Korea Environment and Resources Research Center Korea Research Institute Chemical TechnologyDaejeon 305-606Korea

Use of ultraporous nylon membrane is one of the most widely employed techniques for removal of hard and soft nanoparticles in the semiconductor industry, and the accurate determination of membrane pore size is necessary in order to avoid manufacturing defects caused by contamination. The gold nanoparticle has several benefits for the evaluation of polymeric membranes; however, the nanoparticles agglomerate easily on the nylon membrane and make it difficult to evaluate the membrane precisely. The properties of 2-amino-2-hydroxymethyl-1,3-propanediol(ADP) ligand in gold nanoparticle solution were systematically investigated, and ADP was utilized for improved evaluation of the nylon membranes. Nylon membrane used in this study was prepared by phase inversion techniques. Ultrathin dense layer on top of the membrane surface and Darcy structures in the microporous membrane support were observed. The gold particle rejection was carried out at various p H values from 4 to14 and higher rejection was observed at p H 4 and 8. The suppression of gold colloid agglomeration using ADP and monodispersity of gold colloids was also analyzed by confocal laser scanning microscopy(CLSM), transmission electron microscopy(TEM), and scanning electron microscopy(SEM). van der Waals interaction energy of the particles was reduced in the addition of ADP. The presence of ADP ligand in the gold solutions prevented the agglomeration of gold nanoparticles and reduced the adsorption of the particles on the nylon membrane surface,leading to precise evaluation of membrane pore sizes.

关键词： Particle size Electron microscopy Gold colloid flock Semiconductor

Long-term result of endoscopic Histoacryl （N-butyl-2-cyanoacrylate）injection for treatment of gastric varices

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World Journal of Gastroenterology 2011年第11期17卷 1494-1500页

作者： Eun Jung Kang Soung Won Jeong Jae young Jang Joo young Cho Sae Hwan Lee Hyun Gun kim Sang Gyune kim young Seok kim young Koog Cheon young Deok Cho Hong Soo kim Boo Sung kim Institute for Digestive Research Department of Internal MedicineSoonchunhyang University College of MedicineSeoul HospitalSeoul 140-743South Korea

AIM:To evaluate the long-term efficacy and safety of endoscopic obliteration with Histoacryl  for treatment of gastric variceal bleeding and ***:Between January 1994 and March 2010 at SoonChunHyang University Hospital,a total of 127 patients with gastric varices received Histoacryl  injections *** hundred patients underwent endoscopic Histoacryl  injections because of variceal bleeding,the other 27 patients received such injections as a prophylactic ***:According to Sarin classification,56 patients were GOV1,61 patients were GOV2 and 10 patients were *** of the varices were large(F2 or F3,111 patients).The average volume of Histoacryl  per each session was 1.7±1.3 cc and mean number of sessions was 1.3±0.6.(1 session-98 patients,2 sessions-25 patients,≥3 sessions-4 patients).Twenty-seven patients with high risk of bleeding(large or fundal or RCS+or Child C) received Histoacryl  injection as a primary prophylactic *** these patients,hepatitis B virus was the major etiology of cirrhosis,25 patients showed GOV1 or 2(92.6%)and F2 or F3 accounted for 88.9%(n=24).The rate of initial hemostasis was 98.4%and recurrent bleeding within one year occurred in 18.1%of *** hemostasis during episodes of rebleeding was achieved in 73.9%of *** survival was 50 mo (95%CI 30.5-69.5).Major complications occurred in 4 patients(3.1%).The rebleeding rate in patients with hepatocellular carcinoma or GOV2 was higher than in those with other *** of the 27 subjects who were treated prophylactically experienced treatment-related *** survival rates of the 127 patients at 6 mo,1,3,and 5 years were 92.1%,84.2%,64.2%,and 45.3%,*** 6 mo cumulative survival rate of the 27 patients treated prophylactically was 75%.CONCLUSION:Histoacryl  injection therapy is an effective treatment for gastric varices and also an effective prophylactic treatment of gastric varices which

关键词： Gastric varix Prophylaxis Histoacryl  (Nbutyl-2-cyanoacrylate) Histoacryl  injection Treatment of gastric varix

Byte Frequency Based Indicators for Crypto-Ransomware Detection from Empirical Analysis

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Journal of Computer Science & Technology 2022年第2期37卷 423-442页

作者： Geun Yong kim Joon-young Paik Yeongcheol kim Eun-Sun Cho Department of Computer Science and Engineering Chungnam National UniversityDaejeon 34134South Korea School of Computer Science and Technology Tiangong UniversityTianjin 300387China

File entropy is one of the major indicators of crypto-ransomware because the encryption by ransomware increases the randomness of file ***,entropy-based ransomware detection has certain limitations;for example,when distinguishing ransomware-encrypted files from normal files with inherently high-level entropy,misclassification is very *** addition,the entropy evaluation cost for an entire file renders entropy-based detection impractical for large *** this paper,we propose two indicators based on byte frequency for use in ransomware detection;these are termed EntropySA and DistSA,and both consider the interesting characteristics of certain file subareas termed“sample areas”(SAs).For an encrypted file,both the sampled area and the whole file exhibit high-level randomness,but for a plain file,the sampled area embeds informative structures such as a file header and thus exhibits relatively low-level randomness even though the entire file exhibits high-level *** and DistSA use“byte frequency”and a variation of byte frequency,respectively,derived from sampled *** indicators cause less overhead than other entropy-based detection methods,as experimentally proven using realistic ransomware *** evaluate the effectiveness and feasibility of our indicators,we also employ three expensive but elaborate classification models(neural network,support vector machine and threshold-based approaches).Using these models,our experimental indicators yielded an average Fl-measure of 0.994 and an average detection rate of 99.46%for file encryption attacks by realistic ransomware samples.

关键词： computer security cryptography machine learning ransomware

Effect of Ca addition on the microstructure and mechanical properties of heat-treated Mg-6.0Zn-1.2Y-0.7Zr alloy

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Journal of Magnesium and Alloys 2021年第5期9卷 1636-1648页

作者： young Gil Jung Wonseok Yang Yong Joo kim Shae.K.kim young Ok Yoon Hyunkyu Lim Do Hyang kim Advanced Materials and Process R&D Department Korea Institute of Industrial Technology156Gaetbeol-roIncheon 21999Republic of Korea Department of Metallurgical Engineering Yonsei University50Yonsei-roSeoulSeodaemun-gu 03722Republic of Korea

In this study,the effects of Ca addition on the microstructure,thermal properties,and mechanical properties of a Mg-6.0Zn-1.2Y-0.7Zr(ZWK611)alloy at room temperature and 150℃ were *** an increase in the Ca content,the ignition resistance of the ZWK611 alloy improved and the grains became *** as-cast ZWK611 alloy consisted mainly of the dendriticα-Mg matrix and I-phase(Mg_(3)Zn_(6)Y)at the grain *** the other hand,theτ-(Ca_(2)Mg_(6)Zn_(3))and I-phases were formed in the Ca-added ZWK611 *** fraction of theτ-phase increased with an increase in the Ca *** the solid-solution treatment,these phases remained partially at the grain boundaries of the Ca-added ZWK611 alloys and an additional W-phase(Mg_(3)Zn_(3)Y)was *** phases remaining at the grain boundaries restricted the grain growth through the grain boundary pinning *** aging treatment resulted in the formation of MgZn'precipitates in theα-Mg matrix of the *** precipitates were more uniformly distributed in the Ca-added alloys than in the alloys without ***,the heat treatment-induced precipitation improved the tensile and creep properties of the T6-treated *** T6-treated ZWK611+0.7Ca alloy exhibited the best mechanical properties at room temperature and 150℃ among all the tested alloys.

关键词： Mg-Zn-Y alloys Heat-treatment Precipitate Mechanical properties Thermal analysis