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Effects of elastic-plastic properties of materials on residual indentation impressions in nano-indentation using sharp indenter

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中国有色金属学会会刊：英文版 2012年第S3期22卷 585-595页

作者： Jung-min lee Chan-Joo lee Kyung-Hun lee Byung-min KIM Dongnam Regional Division Korea Institute of Industrial Technology Precision Manufacturing Systems Division Pusan National University School of Mechanical Engineering Pusan National University

One of the primary features of nano-indentation technique is that the contact area induced by an indenter is indirectly measured by a relationship between the penetration depth and the known geometry of the ***,this indirect measurement occasionally leads to inaccurate properties of the indented *** objective of this study is to investigate the effects of E/σr and the strain hardening exponents n of materials on the behaviors of pile-up and sink-in in nano-indentation and to predict n values of materials from the residual indentation *** relations between the residual indentation profile and n value of the indented material were identified by dimensional ***,they were numerically formulated using FE analysis of nano-indentation for 140 different combinations of elastic-plastic parameters such as E,σy and *** parameters of hrp/hm,herp/hm,Rr/hm and HO&P/Hreal were introduced as various dimensionless parameters to represent and quantify the residual indentation profile after *** were subsequently characterized as dimensionless functions using n and E/σr ***,the validity of these functions was verified through 3D FE analysis of nano-indentation for Al 6061-T6 and AISI 1010 materials.

关键词： nano-indentation pile-up sink-in strain hardening exponent FE simulation

Effect of electrical stimulation on neural regeneration via the p38-RhoA and ERK1/2-Bcl-2 pathways in spinal cord-injured rats

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Neural Regeneration Research 2018年第2期13卷 340-346页

作者： min Cheol Joo Chul Hwan Jang jong Tae Park Seung Won Choi Seungil Ro min Seob Kim Moon Young lee Department of Rehabilitation Medicine and Institute of Wonkwang Medical Science School of Medicine Wonkwang University Department of Neurosurgery School of Medicine Wonkwang University Department of Anesthesiology and Pain Medicine School of Medicine Wonkwang University Department of Physiology and Cell Biology School of Medicine University of Nevada Department of Physiology and Institute of Wonkwang Medical Science School of Medicine Wonkwang University

Although electrical stimulation is therapeutically applied for neural regeneration in patients, it remains unclear how electrical stimulation exerts its effects at the molecular level on spinal cord injury （SCI）. To identify the signaling pathway involved in electrical stimulation improving the function of injured spinal cord, 21 female Sprague-Dawley rats were randomly assigned to three groups： control （no surgical intervention, n = 6）, SCI （SCI only, n = 5）, and electrical simulation （ES; SCI induction followed by ES treatment, n = 10）. A complete spinal cord transection was performed at the 10^th thoracic level. Electrical stimulation of the injured spinal cord region was applied for 4 hours per day for 7 days. On days 2 and 7 post SCI, the Touch-Test Sensory Evaluators and the Basso-Beattie-Bresnahan locomotor scale were used to evaluate rat sensory and motor function. Somatosensory-evoked potentials of the tibial nerve of a hind paw of the rat were measured to evaluate the electrophysiological function of injured spinal cord. Western blot analysis was performed to measure p38-RhoA and ERK1/2-Bcl-2 pathways related protein levels in the injured spinal cord. Rat sensory and motor functions were similar between SCI and ES groups. Com- pared with the SCI group, in the ES group, the latencies of the somatosensory-evoked potential of the tibial nerve of rats were significantly shortened, the amplitudes were significantly increased, RhoA protein level was significantly decreased, protein gene product 9.5 expression, ERK1/2, p38, and Bcl-2 protein levels in the spinal cord were significantly increased. These data suggest that ES can promote the recovery of electrophysiological function of the injured spinal cord through regulating p38-RhoA and ERK1/2-Bcl-2 pathway-related protein levels in the injured spinal cord.

关键词： Bcl-2 ERKI/2 p38 PGP9.5 RhoA spinal cord injury somatosensory evoked potential muscle contraction electrical impulses neural regeneration

Synthesis and Gas Sensing of TiO_2 Ultrafine Powders by Precipitating

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稀有金属材料与工程 2006年第A3期35卷 163-164页

作者： min-Hyun Seo Bong-Ho lee jong-Won Kim Gi-Hong Rue Duk-Dong lee Jeung-Soo Huh Department of Sensor and Display Engineering Kyungpook National UniversitySangyuk-DongBukguDaegu 1370Korea Department of Materials Science and Metallurgy Kyungpook National UniversitySangyuk-DongBukguDaegu 1370Korea Department of Nano-science and Technology Kyungpook National UniversitySangyuk-DongBukguDaegu 1370Korea School of Electronic Engineering Kyungpook National UniversitySangyuk-DongBukguDaegu 1370Korea Department of Sensor and Display Engineering Kyungpook National UniversitySangyuk-DongBukguDaegu 1370Korea.Department of Nano-science and TechnologyKyungpook National UniversitySangyuk-DongBukguDaegu 1370Korea

We investigated the gas sensing characteristics of rutile and anatase TiO_2 nano-particle sensors for chemical warfare ***_2 nano-powders with rutile and anatase structure were fabricated by controlling pH value without heat treatment *** mean particle size of TiO_2 powders were below 10 ***-prepared TiO_2 powders have several advantages of nano particle size and high surface area and could be a prominent candidate for ***_2 sensors were examined with DMMP for chemical warfare agents detection.

关键词： TiO2 chemical warfare agents sensor nano-sensor pH

Wire-Shaped 3D-Hybrid Supercapacitors as Substitutes for Batteries

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Nano-Micro Letters 2020年第2期12卷 211-223页

作者： Kyeong‑Nam Kang Ananthakumar Ramadoss Jin‑Wook min jong‑Chul Yoon Deokjung lee Seok Ju Kang Ji‑Hyun Jang School of Energy and Chemical Engineering Low Dimensional Carbon Materials CenterUlsan National Institute of Science and TechnologyUlsan 44919Republic of Korea Laboratory for Advanced Research in Polymeric Materials Central Institute of Plastic Engineering and TechnologyBhubaneswar 751024India School of Mechanical Aerospace and Nuclear EngineeringUlsan National Institute of Science and TechnologyUlsan 44919Republic of Korea

We report a wire-shaped three-dimensional(3D)-hybrid supercapacitor with high volumetric capacitance and high energy density due to an interconnected 3D-configuration of the electrode allowing for large number of electrochemical active sites,easy access of electrolyte ions,and facile charge transport for flexible wearable *** interconnected and compact electrode delivers a high volumetric capacitance(gravimetric capacitance)of 73 F cm−3(2446 F g−1),excellent rate capability,and cycle *** 3D-nickel cobalt-layered double hydroxide onto 3D-nickel wire(NiCo LDH/3D-Ni)//the 3D-manganese oxide onto 3D-nickel wire(Mn3O4/3D-Ni)hybrid supercapacitor exhibits energy density of 153.3 Wh kg−1 and power density of 8810 W kg−*** red lightemitting diode powered by the as-prepared hybrid supercapacitor can operate for 80 min after being charged for tens of seconds and exhibit excellent electrochemical stability under various deformation *** results verify that such wire-shaped 3D-hybrid supercapacitors are promising alternatives for batteries with long charge–discharge times,for smart wearable and implantable devices.

关键词： Three-dimensional(3D)metal current collector Flexible hybrid supercapacitor Wire-shaped supercapacitor High energy density device Fast charging energy storage system

Optimum condition by mechanical characteristic evaluation in friction stir welding for 5083-O Al alloy

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中国有色金属学会会刊：英文版 2009年第B09期19卷 17-22页

作者： min-Su HAN Seung-Jun lee Jae-Cheul PARK Seok-Cheol KO Yong-Bin WOO Seong-jong KIM Division of Marine Engineering Mokpo Maritime University Chungnam Regional Innovation Agency

The mechanical characteristies for friction stir welding (FSW) of 5083-O Al alloy were evaluated. The results show that in FSW at 800 r/min and 124 mm/min, a weld defect is observed at the start point. However, the button shape at the end point is good and the stir zone has a soft appearance. At 267 mm/min, a void occurs at the button. A slight weld defect and rough stir zone are seen both at the start and end points at 342 mm/min. Moreover, at the bottom, a tunnel-type void is observed from an early stage to the end point, and at 1 800 r/min, a weld defect can be found from an early stage to the end point. These defects are rough with imperfect joining due to excessive rotation speed and high physical force. Weld fractures relative to rotational and travel speeds are observed at the stir zone. The optimum FSW conditions are a welding speed of 124 mm/min and a rotational speed of 800 r/min.

关键词：搅拌摩擦焊接摩擦特性机械性能铝合金焊缝缺陷评估优化氧

Human umbilical cord blood-derived mesenchymal stem cells promote regeneration of crush-injured rat sciatic nerves

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Neural Regeneration Research 2012年第26期7卷 2018-2027页

作者： Mi-Ae Sung Hun jong Jung Jung-Woo lee Jin-Yong lee Kang-Mi Pang Sang Bae Yoo Mohammad S. Alrashdan Soung-min Kim Jeong Won Jahng jong-Ho lee Department of Craniofacial Structure & Functional Biology School of Dentistry Seoul National University Seoul Republic of Korea Department of Occupation and Environment Postgraduate College of Medicine Konkuk University Choong-ju Republic of Korea Department of Oral & Maxillofacial Surgery School of Dentistry Seoul National University Seoul Republic of Korea Department of Dentistry Oral and Maxillofacial Surgery Ajou University School of Medicine Suwon Republic of Korea Dental Research Institute Seoul National University Seoul Republic of Korea

Several studies have demonstrated that human umbilical cord blood-derived mesenchymal stem cells can promote neural regeneration following brain injury. However, the therapeutic effects of human umbilical cord blood-derived mesenchymal stem cells in guiding peripheral nerve regeneration remain poorly understood. This study was designed to investigate the effects of human umbilical cord blood-derived mesenchymal stem cells on neural regeneration using a rat sciatic nerve crush injury model. Human umbilical cord blood-derived mesenchymal stem cells （1 ~ 106） or a PBS control were injected into the crush-injured segment of the sciatic nerve. Four weeks after cell injection, brain-derived neurotrophic factor and tyrosine kinase receptor B mRNA expression at the lesion site was increased in comparison to control. Furthermore, sciatic function index, Fluoro Gold-labeled neuron counts and axon density were also significantly increased when compared with control. Our results indicate that human umbilical cord blood-derived mesenchvmal stem cells promote the functinnal r~.RcJv^rv nf P.n I^h-inillr^4 ~r^i~tit, n^r~e

关键词： human umbilical cord blood-derived mesenchymal stem cells sciatic nerve crush injury FluoroGold stem cells peripheral nerve regeneration regeneration neural regeneration

Silver-palladium alloy deposited by DC magnetron sputtering method as lubricant for high temperature application

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中国有色金属学会会刊：英文版 2009年第4期19卷 1001-1004页

作者： Jung-Dae KWON Sung-Hun lee Koo-Hyun lee jong-Joo RHA Kee-Seok NAM Sang-Hoon CHOI Dong-min lee Dong-Il KIM Materials Processing Division Korea Institute of Materials Science Technology Research & Development Institute Korea Plant Service and Engineering

The silver-palladium(Ag-Pd) alloy coating as a solid lubricant was investigated for its application to the high temperature stud bolts used in nuclear power plants.A hex bolt sample was prepared in the following steps:1) bolt surface treatment using alumina grit blasting for cleaning and increasing the surface area;2) nickel(Ni) film coating as a glue layer on the surface of the bolt;and 3) Ag-Pd alloy coating on the Ni *** films were deposited by using a direct current(DC) magnetron sputtering *** thickness and composition of the Ag-Pd alloy film have effect on the friction coefficient,which was determined using axial force measurement.A 500 nm-thick Ag-Pd(80-20,molar ratio) alloy film has the lowest friction coefficient of 0.109.A cyclic test was conducted to evaluate the durability of bolts coated with either the Ag-Pd(80-20) alloy film or N-5000 *** a cycle,the bolts were inserted into a block using a torque wrench,which was followed by heating and *** only one cycle,it was not possible to remove the bolts coated with the N-5000 oil from the ***,the bolts coated with the Ag-Pd(80-20) alloy could be easily removed up until 15 cycles.

关键词：银钯合金直流电高温润滑剂沉积磁控溅射法固体润滑涂层高温螺栓

Development and validation of a clinical nomogram predicting bladder outlet obstruction via routine clinical parameters in men with refractory nonneurogenic lower urinary tract symptoms

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Asian Journal of Andrology 2019年第5期21卷 486-492页

作者： Young Ju lee Jung Keun lee Jung Jun Kim Hak min lee jong Jin Oh Sangchul lee Sang Wook lee Jeong Hyun Kim Seong Jin Jeong Department of Urology Seoul National University Bundang HospitalSeongnam 13620Korea Department of Urology Kangwon National University School of MedicineChuncheon 24341Korea

We aimed to develop and validate a clinical nomogram predicting bladder outlet obstruction(BOO)solely using routine clinical parameters in men with refractory nonneurogenic lower urinary tract symptoms(LUTS).A total of 750 eligible patient ≥50 years of age who had previously not responded(International Prostate Symptom Score[IPSS]improvement2 cmH20 ml^-1 s^-1.A stepwise multivariable logistic regression analysis was conducted to determine the predictors of BOO,and^-coefficients of the final model were selected to create a clinical *** final multivariable logistic regression model showed that age,IPSS,maximum urinary flow rate,postvoid residual volume,total prostate volume,and transitional zone index were significant for predicting BOO;these candidates were used to develop the final *** discrimination performance of the nomogram was 88.3%(95%Cl:82.7%-93.0%,Pmining further treatment,primarily focused on prostatic surgery for BOO,without impeding the detection of possible BOO in men with LUTS that is refractory to empirical medications.

关键词： benign prostatic hyperplasia bladder outlet obstruction lower urinary tract symptoms no mogram urodynamics

Texture tailoring and bendability improvement of rolled AZ31 alloy using {10-12} twinning: The effect of precompression levels

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Journal of Magnesium and Alloys 2019年第4期7卷 648-660页

作者： jong Un lee Ye Jin Kim Sang-Hoon Kim Jeong Hun lee min-Seong Kim Shi-Hoon Choi Byoung Gi Moon Young min Kim Sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Ulsan Regional Division Korea Institute of Industrial TechnologyUlsan 44413Republic of Korea Department of Printed Electronics Engineering Sunchon National UniversitySuncheonJeonnam 57922Republic of Korea Implementation Research Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea

In this study,the texture of a rolled Mg alloy is effectively modified through the application of precompression and subsequent annealing treatment,leading to a remarkable improvement in the bending formability of the alloy at room *** induces lattice reorientation through{10-12}twinning,and annealing treatment reduces the stored strain energy of the precompressed material,which results in the formation of a stable grain structure with two dominant texture *** an increase in precompression,the tensile strain in the outer region of the bending samples is accommodated to a greater extent due to more pronounced{10-12}twinning and basal *** a result,the bending formability of the material at room temperature improves with greater *** variation in microstructure,texture,and bending behavior in relation to the degree of precompression is discussed in detail.

关键词： Magnesium Bending Formability Twinning Texture