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Selective laser melting of Fe-Ni-Cr layer on AISI H13 tool steel

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中国有色金属学会会刊：英文版 2009年第4期19卷 921-924页

作者： Byeong-Don JOO Jeong-Hwan jang Jae-Ho LEE young-Myung SON young-Hoon MOON School of Mechanical Engineering Pusan National University

An attempt to fabricate Fe-Ni-Cr coating on AISI H13 tool steel was performed with selective laser ***-Ni-Cr coating was produced by experimental facilities consisting of a 200 W fiber laser which can be focused to 80 μm and atmospheric chamber which can control atmospheric pressure with N2 or *** layer was fabricated with various process parameters such as laser power,scan rate and fill *** quality and coating thickness were measured and *** different surface patterns,such as typeⅠ,typeⅡand type Ⅲ,are shown with various test conditions and smooth regular pattern is obtained under the conditions as 10 μm of fill spacing,50-350 mm/s of scan rate and 40 μm of fill spacing,10-150 mm/s of scan *** maximum coating thickness is increased with power elevation or scan rate drop,and average thickness of 10 μm fill spacing is lower than that of 40 μm fill spacing.

关键词：镍铬涂层工具钢激光熔融社会扫描速度铁涂层厚度光纤激光器

Effect of Laser Parameters on Sintered Powder Morphology

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Journal of Materials Science & Technology 2010年第4期26卷 375-378页

作者： Byeong-Don Joo Jeong-Hwan jang Jae-Ho Lee young-Myung Son young-Hoon Moon Engineering Research Center for Net Shape and Die Manufacturing School of Mechanical EngineeringPusan National University

Selective laser sintering is a kind of rapid prototyping process whereby a three-dimensional part is built layerwise by laser scanning a powder. This process is highly inffuenced by powder and laser parameters such as laser power, scan rate, spot size and layer thickness. Therefore a study on fabricating a line with Fe-Ni-Cr powder on AISI H13 tool steel has been performed by selective laser sintering. In this study, fabrication was performed by experimental facilities consisting of a 200W fiber laser which can be focused to 0.08 mm and atmospheric chamber which can control atmospheric pressure with argon. The line was fabricated with various laser power, scan rate and layer thickness. Line width and surface quality were investigated. With power increase or layer thickness decrease, line width was decreased and line surface quality was improved with scan rate optimization.

关键词： Selective laser sintering Direct fabrication Fiber laser

Mechanisms linking gut microbial metabolites to insulin resistance

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World Journal of Diabetes 2021年第6期12卷 730-744页

作者： Hye Rim jang Hui-young Lee Laboratory of Mitochondrial and Metabolic Diseases Department of Health Sciences and TechnologyGAIHSTGachon UniversityIncheon 21999South Korea Korea Mouse Metabolic Phenotyping Center Lee Gil Ya Cancer and Diabetes InstituteGachon UniversityIncheon 21999South Korea Division of Molecular Medicine Department of MedicineGachon University College of MedicineIncheon 21936South Korea

Insulin resistance is the rate-limiting step in the development of metabolic diseases,including type 2 *** gut microbiota has been implicated in host energy metabolism and metabolic diseases and is recognized as a quantitatively important organelle in host metabolism,as the human gut harbors 10 trillion bacterial *** microbiota break down various nutrients and produce metabolites that play fundamental roles in host metabolism and aid in the identification of possible therapeutic targets for metabolic ***,understanding the various effects of bacterial metabolites in the development of insulin resistance is ***,we review the mechanisms linking gut microbial metabolites to insulin resistance in various insulin-responsive tissues.

关键词： Insulin resistance Skeletal muscle Liver Adipose tissue Intestine Gut bacterial metabolites

Case Report:Congenital atresia of the left main coronary artery in an infant

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2010年第7期11卷 539-541页

作者： Su Ye SOHN Gi young jang Byung Min CHOI Department of Pediatrics Korea University Hospital

Congenital atresia of the left main coronary artery is a rare occurrence, and surgical revascularizationbypass graft is required. We here report a rare case of congenital coronary anomaly in an infant. A lO-month-old male infant was admitted to the hospital with heart failure symptoms. Echocardiographic examinations revealed mitral valve regurgitation and ischemic changes of the anterolateral atresia of the left main coronary artery with a severe papillary muscle and chordae. Coronary angiography showed hypoplastic left anterior descending artery and a circumflex coronary artery. Unfortunately, sudden cardiac arrest occurred after catheterization and the infant did not recover despite of immediate cardiopulmonary resuscitation. Further studies are needed to find a newer diagnostic method to detect coronary anomaly in an infant, and coronary angiography, if necessary, has to be performed very carefully.

关键词： Conqenital heart disease Anomalous coronaries Infant

Passive control of along-wind response of tall building

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Journal of Central South University 2014年第10期21卷 4002-4006页

作者： KIM young-moon YOU Ki-pyo YOU jang-youl Department of Architecture Engineering Chonbuk National University Long-Span Steel Frame System Research Center Chonbuk National University KOCED Wind Tunnel Center Chonbuk National University

Most of modern tall buildings using lighter construction materials with high strength and less stiffness are more flexible, which occurs excessive wind-induced vibration, resulting in occupant discomfort and structural unsafety. It is necessary to predict wind-induced vibration response and find out a method to mitigate such an excessive wind-induced vibration at the preliminary design stage. Recently, many studies have been conducted in using actuator control force based on the linear quadratic optimum control algorithm. It was accepted as a common knowledge that the performance of passive tuned mass damper(TMD) could increase by incorporating a feedback active control force in the design of TMD, which is called active tuned mass damper(ATMD). However, the fact that ATMD is superior to TMD to reduce wind-induced vibration of a tall building is still a question. The effectiveness of TMD for mitigating the along-wind vibration of a tall building was investigated. Optimum parameters of tuning frequency and damping ratio for TMD under a random load which has a white noise spectra were used. Fluctuating along-wind load acting on a tall building treated as a stationary Gaussian random process was simulated numerically using the along-wind load spectra. And using this simulated along-wind load, along-wind responses of a tall building with and without TMD were calculated and the effectiveness of TMD in mitigating the along-wind response of a tall building was found out.

关键词： tuned mass damper(TMD) along-wind vibration tall building

Effects of visual information regarding tactile stimulation on the somatosensory cortical activation：a functional MRI study

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Neural Regeneration Research 2017年第7期12卷 1119-1123页

作者： Hyeok Gyu Kwon Sung Ho jang Mi young Lee Department of Physical Therapy College of Health Sciences Catholic University of Pusan Pusan Republic of Korea Department of Physical Medicine and Rehabilitation College of Medicine Yeungnam University Daegu Republic of Korea Department of Physical Therapy College of Health and Therapy Daegu Haany University Gyeongsansi Republic of Korea

Many studies have investigated the evidence for tactile and visual interactive responses to activation of various brain ***,few studies have reported on the effects of visuo-tactile multisensory integration on the amount of brain activation on the somatosensory cortical *** aim of this study was to examine whether coincidental information obtained by tactile stimulation can affect the somatosensory cortical activation using functional *** right-handed healthy subjects were recruited for this *** tasks（tactile stimulation and visuotactile stimulation）were performed using a block paradigm during f MRI *** the tactile stimulation task,in subjects with eyes closed,tactile stimulation was applied on the dorsum of the right hand,corresponding to the proximal to distal directions,using a rubber *** the visuotactile stimulation task,tactile stimulation was applied to observe the attached mirror in the MRI chamber reflecting their hands being touched with the *** the result of SPM group analysis,we found brain activation on the somatosensory cortical *** stimulation task induced brain activations in the left primary sensory-motor cortex（SM1）and secondary somatosensory cortex（S2）.In the visuo-tactile stimulation task,brain activations were observed in the both SM1,both S2,and right posterior parietal *** all tasks,the peak activation was detected in the contralateral *** examined the effects of visuo-tactile multisensory integration on the SM1 and found that visual information during tactile stimulation could enhance activations on SM1 compared to the tactile unisensory stimulation.

关键词： nerve regeneration functional MRI somatosensory cortex somatosensory cortical activation visuotactile stimulation neural regeneration

Materials property mapping from atomic scale imaging via machine learning based sub-pixel processing

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npj Computational Materials 2022年第1期8卷 1868-1876页

作者： Junghun Han Kyoung-June Go Jinhyuk jang Sejung Yang Si-young Choi Department of Biomedical Engineering Yonsei UniversityWonju26493Republic of Korea Department of Materials Science and Engineering Pohang University of Science and TechnologyPohang37673Republic of Korea

Direct visualization of the atomic structure in scanning transmission electron microscopy has led to a comprehensive understanding of the structure-property ***,a reliable characterization of the structural transition on a picometric scale is still challenging because of the limited spatial resolution and ***,we demonstrate that the primary segmentation of atomic signals from background,succeeded by a denoising process,enables structural analysis in a sub-pixel *** noise is eliminated using the block matching and three-dimensional filtering with Anscombe transformation,and remnant noise is removed via morphological filtering,which results in an increase of peak signal-to-noise ratio from 7 to 11 *** the centroids of atomic columns segmented via K-means clustering,an unsupervised method for robust thresholding,achieves an average error of less than 0.7 pixel,which corresponds to 4.6 *** study will contribute to a profound understanding of the local structural dynamics in crystal structures.

关键词： property filtering removed

Verification of Beam Models for Ionic Polymer-Metal Composite Actuator

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Journal of Bionic Engineering 2009年第3期6卷 232-238页

作者： Hoon Cheol Park Quoc Viet Nguyen jang Woo Lee young Tai Yoo Artificial Muscle Research Center Konkuk University Department of Advanced Technology Fusion Konkuk University Department of Materials Chemistry and Engineering Konkuk University

Ionic Polymer-Metal Composite (IPMC) can work as an actuator by applying a few voltages.A thick IPMC actuator,where Nafion-117 membrane was synthesized with polypyrrole/alumina composite filler,was analyzed to verify the equivalent beam and equivalent bimorph beam *** blocking force and tip displacement of the IPMC actuator were measured with a DC power supply and young's modulus of the IPMC strip was measured by bending and tensile tests *** calculated maximum tip displacement and the young's modulus by the equivalent beam model were almost identical to the corresponding measured *** element analysis with thermal analogy technique was utilized in the equivalent bimorph beam model to numerically reproduce the force-displacement relationship of the IPMC *** results by the equivalent bimorph beam model agreed well with the force-displacement relationship acquired by the measured *** is confirmed that the equivalent beam and equivalent bimorph beam models are practically and effectively suitable for predicting the tip displacement,blocking force and young's modulus of IPMC actuators with different thickness and different composite of ionic polymer membrane.

关键词： jonic polymer-metal composite beam model displacement force

Across and along-wind responses of tall building

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Journal of Central South University 2014年第11期21卷 4404-4408页

作者： KIM young-moon YOU Ki-pyo YOU jang-youl Department of Architecture Engineering Long-Span Steel Frame System Research CenterChonbuk National UniversityChonju 561-756 Korea KOCED Wind Tunnel Center Chonbuk National UniversityChonju 561-756 Korea

Most modern tall buildings using lighter construction materials are more flexible, which can lead to excessive wind-induced vibrations resulting in occupant discomfort and structural unsafety. It is necessary to predict and mitigate such wind-induced vibration at the preliminary design stage. Fluctuating across and along-wind loads acting on a tall building that could not be formulated theoretically were simulated numerically in the time domain using known across and along-wind load spectra. These simulated wind loads were used to estimate the across and along-wind responses of a tall building, which are less narrow-banded processes, based on the state space variable approach. The simulated across-wind response of root-mean-square value(0.0047) and that of KAREEM's(0.0040) and the simulated along-wind response of root-mean-square value(0.021) and that of SOLARI's(0.027) were compared. It is found that these are good approximations of closed form responses. Therefore, these numerically simulated across and along-wind loads can be used for across and along-wind responses estimation for the wind-resistant design of a tall building at the preliminary design stage.

关键词： across-wind load along-wind load across and along-wind responses tall building