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Formation of nanocrystalline microstructure in arc ion plated CrN films

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Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 73-77页

作者： Qi-min WANG se-Hun KWON Kwang-Ho KIM National Core Research Center for Hybrid Materials Solution Pusan National University Busan 609-735 Korea School of Materials Science and Engineering Pusan National University Busan 609-735 Korea

Applying negative bias voltages caused significant microstructure changes in arc ion plated CrN films. Nanocrystalline microstructures were obtained by adjusting the negative bias voltage. Structural characterizations of the films were carried out using X-ray diffractometry (XRD) and high-resolution transmission electron microscopy (HR-TEM). The results indicated that increasing ion bombardment by applying negative bias voltages resulted in the formation of defects in the CrN films, inducing microstructure evolution from micro-columnar to nanocrystalline. The microhardness and residual stresses of the films were also affected. Based on the experimental results, the evolution mechanisms of the film microstructure and properties were discussed by considering ion bombardment effects.

关键词： CrN thin films deposition microstructure arc ion plating ion bombardment

Dracocephalum palmatum Stephan extract induces apoptosis in human prostate cancer cells via the caspase-8-mediated extrinsic pathway

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Chinese Journal of Natural Medicines 2020年第10期18卷 793-800页

作者： LEE se-Eun OKHLOPKOVA Zhanna LIM Chiyeon CHO Suin School of Korean Medicine Pusan National UniversityYangsan-si 50612Republic of Korea Department of Biology North-Eastern Federal UniversityYakutsk 677027Russia College of Medicine Dongguk UniversityGyeonggi-do 10326Republic of Korea

Dracocephalum palmatum Stephan is a medicinal plant traditionally used by nomadic people in Eastern Russia;however,research on this plant is currently ***,although studies have been conducted on the constituents of this plant and their antioxidant effects,data on its various pharmacological activities are still ***,this study examined the anticancer potential of the dried leaves of *** S.(DpL)using human prostate cancer PC-3 *** antioxidant potential of DpL was evaluated by estimating the total flavonoid and total phenolic content(TFC and TPC,respectively).Additionally,we investigated the effects of the DpL ethyl acetate fraction(DpLE)on cell proliferation,intracellular reactive oxygen species(ROS)generation,apoptosis,and cell cycle arrest in this cell *** expression levels of superoxide dismutase(SOD)-1,SOD-2,B-cell lymphoma 2(Bcl-2)and Bcl-2 associated X(Bax)ratio,phospho-protein kinase B(p-AKT),cleaved caspase-8,poly adenosine diphosphate(ADP)ribose polymerase(PARP),and cleaved-PARP were evaluated by western *** results indicated that DpLE causes apoptosis and exerts intracellular ROS-independent anticancer effects on prostate cancer cells,associated with increased SOD-2,cleaved caspase-8,and cleaved-PARP expression and inhibited p-AKT ***,DpLE may be a potential resource for the development of promising chemotherapeutic agents for prostate cancer.

关键词： Dracocephalum palmatum Stephan Prostate cancer Apoptosis Caspase-8

Fatigue strength evaluation of self-piercing riveted joints of AZ31 Mg alloy and cold-rolled steel sheets

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Journal of Magnesium and Alloys 2020年第1期8卷 241-251页

作者： se-Hyung Kang Dong-Woon Han Ho-Kyung Kim Graduate School Seoul National University of Science and TechnologySeoul01811South Korea Department of Mechanical and Automotive Engineering Seoul National University of Science and TechnologySeoul01811 South Korea

The application of magnesium alloys to automobiles is increasing due to their superior specific strength and specific *** this study,an upper sheet of AZ31 magnesium alloy and a lower sheet of cold-rolled steel were joined by self-piercing riveting(SPR),a method commonly used to join automotive panels.A cross-shaped specimen was fabricated with a punching force of 35 kN,which exhibited the best joint strength for the SPR joint specimen *** and fatigue strengths were evaluated using cross-shaped specimens at loading angles of 0°,45°,and 90°.The load amplitude corresponding to the fatigue endurance limit was assumed to be at 106 cycles,and the fatigue ratios(=fatigue endurance limit/static strength)at the loading angles of 0°,45°,and 90°are 22%,13%,and 9%,*** all three loading angle specimens,fatigue cracks initiated at the triple point where the rivet shank,the upper sheet and the lower sheet are in contact with each other,with the cracks propagating through the thickness of the upper sheet and ultimately leading to *** fatigue lifetimes were evaluated through the von-Mises stress,maximum principal stress,and equivalent stress intensity *** was found that the fatigue lifetimes could be evaluated most appropriately through the maximum principal stress.

关键词： self-piercing riveting Magnesium alloy Fatigue strength Maximum principal stress Fatigue lifetime

Effect of post heat-treatment on the microstructure and high-temperature oxidation behavior of precipitation hardened IN738LC superalloy fabricated by selective laser melting

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Journal of Materials Science & Technology 2021年第17期76卷 95-103页

作者： Kyu-Sik Kim Sangsun Yang Myeong-se Kim Kee-Ahn Lee Department of Materials Science and Engineering Inha UniversityIncheon 22212Republic of Korea Korea Institute of Materials Science Changwon51508Republic of Korea Auratech Co. Ltd.Seongnam13449Republic of Korea

The present study investigated the effect of as-built and post heat-treated microstructures of IN738LC alloy fabricated via selective laser melting process on high temperature oxidation *** as-built microstructure showed fine cell and columnar structure due to high cooling *** element segregation was observed in inter-cell/inter-columnar *** post heat-treatment,the initially-observed cell structure disappeared,instead bimodal Ni_3(Al,Ti)particles *** temperature(1273 K and 1373 K)oxidation test results showed parabolic oxidation curves regardless of temperature and initial *** as-built IN738LC fabricated via the selective laser melting process displayed oxidation resistance similar to or slightly better than that of IN738LC fabricated via wrought or cast ***-treated SLM IN738LC,although had similar oxidation weight-gain values to those of the SLM asbuilt material at 1273K,showed relatively better oxidation resistance at 1373 *** Ni_3(Al,Ti)precipitate formed in the post heat treatment changed the local chemical composition,thereby led to changes in alumina former/chromia former location and fraction on the alloy *** was concluded that in heat-treated IN738LC increased alumina former fraction was found,and this resulted in excellent oxidation resistance and relatively low weight-gain.

关键词： IN738LC selective laser melting High temperature oxidation Post heat-treatment Oxidation mechanism

Boosted Lithium-Ion Transport Kinetics in n-Type Siloxene Anodes Enabled by selective Nucleophilic Substitution of Phosphorus

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Nano-Micro Letters 2024年第10期16卷 618-637页

作者： se In Kim Woong-Ju Kim Jin Gu Kang Dong-Wan Kim School of Civil Environmental and Architectural EngineeringKorea University02841 SeoulSouth Korea Nanophotonics Research Center Korea Institute of Science and Technology02792 SeoulSouth Korea

Doped two-dimensional(2D)materials hold significant promise for advancing many technologies,such as microelectronics,optoelectronics,and energy ***,n-type 2D oxidized Si nanosheets,namely n-type siloxene(n-SX),are employed as Li-ion battery *** thermal evaporation of sodium hypophosphite at 275℃,P atoms are effectively incorporated into siloxene(SX)without compromising its 2D layered morphology and unique Kautsky-type crystal ***,selective nucleophilic substitution occurs,with only Si atoms being replaced by P atoms in the O_(3)≡Si-H *** resulting n-SX possesses two delocalized electrons arising from the presence of two electron donor types:(i)P atoms residing in Si sites and(ii)H *** doping concentrations are varied by controlling the amount of precursors or their mean free *** at 2000 mA g^(-1),the n-SX electrode with the optimized doping concentration(6.7×10^(19) atoms cm^(-3))delivers a capacity of 594 mAh g^(-1) with a 73%capacity retention after 500 *** improvements originate from the enhanced kinetics of charge transport processes,including electronic conduction,charge transfer,and solid-state *** approach proposed herein offers an unprecedented route for engineering SX anodes to boost Li-ion storage.

关键词： Li-ion battery Two-dimensional N-type siloxene Doping mechanism Kinetics

Effect of carbon on microstructure of CrAlC_xN_(1-x) coatings by hybrid coating system

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Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 78-82页

作者： Sung-Kyu AHN se-Hun KWON Kwang-Ho KIM National Core Research Center for Hybrid Materials Solution Pusan National University School of Materials Science and Engineering Pusan National University

A systematic investigation of the microstructure of CrA1CxN1-x coatings as a function of carbon contents was conducted. Quaternary CrA1CxN1-x coatings were deposited on Si wafers by a hybrid coating system combining an arc-ion plating technique and a DC reactive magnetron sputtering technique using Cr and AI targets in the Ar/N2/CH4 gaseous mixture. The effect of carbon content on microstructure of CrA1C^N~ x coatings was investigated with instrumental analyses of X-ray diffraction, X-ray photoelectron, and high-resolution transmission electron microscopy. The results show that the carbon content of CrA1CxN1-x coatings linearly increases with increasing CH4/（CH4/N2） gas flow rate ratio. The surface roughness of the CrA1CxN1-x coating layer decreases with the increase of carbon content.

关键词： CrA1C,N1-x, coating nanocomposite microstructure hybrid coating system

Unexpected complication during extracorporeal membrane oxygenation support: Ventilator associated systemic air embolism

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World Journal of Clinical Cases 2018年第9期6卷 274-278页

作者： se-Min Ryu Sung-Min Park Department of Thoracic and Cardiovascular Surgery Kangwon National University Hospital School of Medicine Kangwon National Univerity

Systemic air embolism through a bronchovenous fistu-la(BVF) has been described in patients undergoing positive-pressure ventilation. However, no report has mentioned the potential risks of systemic air embolism through a BVF in patients undergoing extracorporeal membrane oxygenation(ECMO). Positive-pressure ventilation and ECMO support in patients with lung injury can increase the risk of systemic air embolism through a BVF. Increased alveolar pressure, decreased pulmonary venous pressure, and anticoagulation are thought to be the factors that contribute to this complication. Here, we present a case of systemic air embolism in a patient with ECMO and mechanical ventilator support.

关键词： Air embolism Extracorporeal membrane oxygenation Cerebral embolism Positive-pressure ventilation Cardio-pulmonary resuscitation

川中丘陵区自然沟渠水体与沉积物中砷的分布特征及污染评价

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环境科学学报 2018年第12期38卷 4737-4744页

作者：龙虹竹刘红兵汪涛赵原 NseNGA Kumwimba matthe 中国科学院水利部成都山地灾害与环境研究所成都610041 四川省农业厅土壤肥料与资源环境处成都610041

通过对川中丘陵区72条自然沟渠水体和沉积物总砷含量的调查与分析,研究了该区自然沟渠水体和沉积物总砷含量的分布特征,并利用综合指数法和地累积指数法分别对该区自然沟渠水体和沉积物总砷的污染状况进行了评价.结果表明:①川中丘陵区... 详细信息

通过对川中丘陵区72条自然沟渠水体和沉积物总砷含量的调查与分析,研究了该区自然沟渠水体和沉积物总砷含量的分布特征,并利用综合指数法和地累积指数法分别对该区自然沟渠水体和沉积物总砷的污染状况进行了评价.结果表明:①川中丘陵区自然沟渠水体总砷含量在2.20～44.13μg·L^(-1)之间,平均值为7.44μg·L^(-1),其中,有22.22%的沟渠水体总砷含量超过WHO限定标准;沉积物总砷含量在3.40～17.78 mg·kg^(-1)之间,平均值为8.64 mg·kg^(-1),有5.56%的沟渠沉积物总砷含量超过国家一级土壤标准;②不同类型自然沟渠水体和沉积物总砷含量差异显著,沟渠水体总砷含量大小顺序为:居民区沟渠>水田沟渠>旱地沟渠>荒地沟渠;沉积物总砷含量大小顺序为:居民区沟渠>水田沟渠>荒地沟渠>旱地沟渠;③自然沟渠水体总砷含量与水体总氮、总磷含量呈显著正相关,沉积物总砷含量与沉积物总氮、总磷和有机质含量均呈显著正相关;④水体和沉积物总砷含量评价结果显示,川中丘陵区大部分自然沟渠总砷含量处于清洁水平,但仍有部分自然沟渠处于轻度污染状态,具有潜在的砷污染风险.

关键词：砷污染水体沉积物自然沟渠风险评价

An Improved Time Feedforward Connections Recurrent Neural Networks

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Intelligent Automation & Soft Computing 2023年第6期36卷 2743-2755页

作者： Jin Wang Yongsong Zou se-Jung Lim School of Hydraulic&Environmental Engineering Changsha University of Science&TechnologyChangsha410014China School of Computer&Communication Engineering Changsha University of Science&TechnologyChangsha410014China AI Liberal Arts Studies Division of ConvergenceHonam UniversityGwangju-si62399Korea

Recurrent Neural Networks(RNNs)have been widely applied to deal with temporal problems,such as flood forecasting and financial data *** the one hand,traditional RNNs models amplify the gradient issue due to the strict time serial dependency,making it difficult to realize a long-term memory *** the other hand,RNNs cells are highly complex,which will signifi-cantly increase computational complexity and cause waste of computational resources during model *** this paper,an improved Time Feedforward Connections Recurrent Neural Networks(TFC-RNNs)model was first proposed to address the gradient issue.A parallel branch was introduced for the hidden state at time t−2 to be directly transferred to time t without the nonlinear transforma-tion at time t−*** is effective in improving the long-term dependence of ***,a novel cell structure named Single Gate Recurrent Unit(SGRU)was *** cell structure can reduce the number of parameters for RNNs cell,consequently reducing the computational ***,applying SGRU to TFC-RNNs as a new TFC-SGRU model solves the above two ***,the performance of our proposed TFC-SGRU was verified through sev-eral experiments in terms of long-term memory and anti-interference *** results demonstrated that our proposed TFC-SGRU model can cap-ture helpful information with time step 1500 and effectively filter out the *** TFC-SGRU model accuracy is better than the LSTM and GRU models regarding language processing ability.

关键词： Time feedforward connections long-short term memory gated recurrent unit SGRU RNNs