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Microstructure evolution and mechanical properties of Ti-B-N coatings deposited by plasma-enhanced chemical vapor deposition

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中国有色金属学会会刊：英文版 2012年第S3期22卷 722-728页

作者： Jung ho SHIN Kwang Soo ChoI Tie-gang WANG Kwang ho kim Roman NOWAK National Core Research Center for Hybrid Materials Solution Pusan National University School of Materials Science and Engineering Pusan National University State Key Laboratory of Corrosion and Protection Institute of Metal ResearchChinese Academy of Sciences School of Chemical Technology Aalto University

Ternary Ti-B-N coatings were synthesized on AISI 304 and Si wafer by plasma-enhanced chemical vapor deposition (PECVD) technique using a gaseous mixture of TiCl4,BCl3,H2,N2,and *** virtue of X-ray diffraction analysis,X-ray photoelectron spectroscopy,scanning electron microscope,and high-resolution transmission electron microscope,the influences of B content on the microstructure and properties of Ti B N coatings were investigated *** results indicated that the microstructure and mechanical properties of Ti-B-N coatings largely depend on the transformation from FCC-TiN phase to HCP-TiB2 *** increasing B content and decreasing N content in the coatings,the coating microstructure evolves gradually from FCC-TiN/a-BN to HCP-TiB2 /a-BN via FCC-TiN+HCP-TiB2/*** highest microhardness of about 34 GPa is achieved,which corresponds to the nanocomposite Ti-63%B-N (mole fraction) coating consisting of the HCP-TiB2 nano-crystallites and amorphous BN *** lowest friction-coefficient was observed for the nanocomposite Ti-41%B-N (mole fraction) coating consisting of the FCC-TiN nanocrystallites and amorphous BN

关键词： Ti-B-N coating plasma-enhanced chemical vapor deposition (PECVD) nanocomposite coating hardness friction coefficient

Passivation engineering via silica‐encapsulated quantum dots for highly sensitive photodetection

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Carbon Energy 2023年第9期5卷 49-62页

作者： Ji yun Chun Byung Gi kim Jin Young kim Woongsik Jang Dong Hwan Wang School of Integrative Engineering Chung‐Ang UniversitySeoulRepublic of Korea

Organometal halide perovskites are promising semiconducting materials for photodetectors because of their favorable optoelectrical *** nanoscale perovskite materials such as quantum dots(QDs)show novel behavior,they have intrinsic stability *** this study,an effectively silane barrier-capped quantum dot(QD@APDEMS)is thinly applied onto a bulk perovskite photosensitive layer for use in ***@APDEMS is synthesized with a silane ligand with hydrophobic CH_(3)-terminal groups,resulting in excellent dispersibility and durability to enable effective *** introduction of the QD@APDEMS layer results in the formation of a lowdefect perovskite film with enlarged *** is attributed to the grain boundary interconnection effect via interaction between the functional groups of QD@APDEMS and uncoordinated Pb^(2+)in grain *** passivating the grain boundaries,where various trap sites are distributed,hole chargecarrier injection and shunt leakage can be ***,from the energy point of view,the deep highest occupied molecular orbital(hoMO)level of QD@APDEMS can work as a hole charge injection *** charge dynamics(generation,transfer,and recombination properties)and reduced trap density of QD@APDEMS are *** this perovskite film is used in a photodetector,the device performance(especially the detectivity)stands out among existing perovskites evaluated for energy sensing device applications.

关键词： grain boundary passivation perovskite quantum dots photodetectors photosensitive layers trap

Adhesion and Suction Functions of the Tip Region of a Nectar-drinking Butterfly Proboscis

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Journal of Bionic Engineering 2017年第4期14卷 600-606页

作者： Seung Chul Lee Jun ho kim Sang Joon Lee Department of Mechanical Engineering Pohang University of Science and Technology Pohang 37673 Gyeongbuk Republic of Korea Center for Biofluid and Biomimic Research Pohang University of Science and Technology Pohang 37673 Gyeongbuk Republic of Korea

In this study, we investigated the dynamic functions of the tip region of the butterfly proboscis through which liquid is sucked during liquid feeding. The microstructures and flow patterns in the tip region of the proboscis were in vivo analyzed. The tip region can be divided into two functional sections： namely adhesion and suction sections. The liquid adheres to the adhesion section during liquid suction. Although the tip region has numerous slits connected to food canal of the proboscis, liquid is mainly sucked through the suction section, which section is submerged in the fluid pulled by the adhesion section and then successfully imbibes liquid. To check the dynamic functions of the tip region, we fabricated a suction tip model having adhesion and suction parts. The in vitro model experiments show that the hydrophilicity of the adhesion part and the existence of the suction inlet improve the liquid uptake driven by a suction pump. This study may provide insights for the biomimetic design of nectar-feeding butterflies.

关键词： butterfly proboscis nectar-feeding strategy suction

Optimization of post-warranty sequential inspection for second-hand products

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Journal of Systems Engineering and Electronics 2017年第4期28卷 793-800页

作者： Dae-Kyung kim Jae-Hak Lim Dong ho Park Department of Statistics Chonbuk National University Department of Management & Accounting Hanbat National University Industry Academic Cooperation Foundation Hallym University

This paper considers an optimal sequential inspection schedule for a second-hand product after that the free nonrenewable warranty is expired. The length of warranty is prespecified and during the warranty period, the product is minimally repaired by the dealer when it fails. Following the expiration of the non-renewing warranty, the product is inspected and upgraded sequentially a fixed number of times at the expenses of the *** each inspection, the failure rate of the product is reduced proportionally so that the product is upgraded. The product is assumed to deteriorate as it ages and the replacement of the product occurs when a fixed number of inspections are rendered. In addition,the intervals between two successive inspections are assumed to decrease monotonically. The main objective of this paper is to determine the optimal improvement level to upgrade the product at each inspection so that the expected maintenance cost during the life cycle of the product is minimized from the perspective of the customer. Under the given cost structures, we derive an explicit formula to obtain the expected maintenance cost incurred during the life cycle of the product and discuss the method to find the optimal level of the improvement analytically in case the failure times follow the Weibull distribution. Numerical results are analyzed to observe the impact of relevant parameters on the optimal solution.

关键词： second-hand product sequential inspection upgrade action life cycle of the product expected maintenance cost free non-renewable warranty

3D printed energy devices:generation,conversion,and storage

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Microsystems & Nanoengineering 2024年第4期10卷 23-41页

作者： Jin-ho Son hongseok kim Yoonseob Choi howon Lee Department of Mechanical Engineering Institute of Advanced Machines and DesignSeoul National UniversitySeoulRepublic of Korea

The energy devices for generation,conversion,and storage of electricity are widely used across diverse aspects of human life and various ***-dimensional(3D)printing has emerged as a promising technology for the fabrication of energy devices due to its unique capability of manufacturing complex shapes across different length scales.3D-printed energy devices can have intricate 3D structures for significant performance enhancement,which are otherwise impossible to achieve through conventional manufacturing ***,recent progress has witnessed that 3D-printed energy devices with micro-lattice structures surpass their bulk counterparts in terms of mechanical properties as well as electrical *** existing literature focuses mostly on specific aspects of individual printed energy devices,a brief overview collectively covering the wide landscape of energy applications is *** review provides a concise summary of recent advancements of 3D-printed energy *** classify these devices into three functional categories;generation,conversion,and storage of energy,offering insight on the recent progress within each ***,current challenges and future prospects associated with 3Dprinted energy devices are discussed,emphasizing their potential to advance sustainable energy solutions.

关键词： 3D printing 3D-printed energy device Energy generation device Energy conversion device Energy storage device

Reaction mechanism and additional lithium storage of mesoporous MnO_(2) anode in Li batteries

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Journal of Energy Chemistry 2021年第2期30卷 276-284,I0010页

作者： Jaesang Yoon Woosung Choi Taewhan kim Hyunwoo kim yun Seok Choi Ji Man kim Won-Sub Yoon Department of Energy Science Sungkyunkwan UniversitySuwon 16419South Korea Department of Chemistry Sungkyunkwan UniversitySuwon 16419South Korea

Nanostructured transition metal oxides,employed as anode materials for lithium-ion batteries,exhibit a higher capacity than the theoretical capacity based on the conversion *** date,the reasons behind this phenomenon are *** the one-step evolution of anode material for lithium-ion batteries,it is essential to understand the lithium storage reaction mechanism of the anode ***,we provide a detailed report on the lithium storage and release mechanism of MnO2,using synchrotron-based X-ray techniques.X-ray diffraction and X-ray absorption spectroscopy results indicate that during the first discharge,MnO2 is reduced in the order of MnO2→LixMnO2(1

关键词： Mesoporous MnO_(2) Reaction mechanism Electrolyte-derived surface layer Synchrotron-based X-ray techniques Anode Li battery

Fabrication and Characterization of Electrodeposited Ni-SiC-h/BN Composite Coatings

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Journal of Materials Science & Technology 2014年第8期30卷 796-802页

作者： Gobinda Gyawali Hyung-Suk kim Khagendra Tripathi Tae-ho kim Soo Wohn Lee Research Center for Eco-Multifunctional Nano Materials Sun Moon UniversityAsanRepublic of Korea Department of Environmental Engineering Sun Moon UniversityChungnam 336-708Republic of Korea

Ni—SiC—h/BN composite materials were prepared by electrodeposition technique with the dispersion of SiC（10 g/L） and h/BN nanosheets（10 g/L） in a nickel sulfamate electrolytic *** ratio of sodium dodecyl sulfate（SDS） and cetyltrymethyl ammonium bromide（CTAB） surfactants were used to evaluate the effect of surfactants on the properties of the electrodeposited composite *** coating samples were characterized by scanning electron microscopy,X-ray diffraction,Vickers microhardness test,scratch and tribology *** results revealed that the co-deposition of nanoparticles was significantly influenced by surfactants during electrodeposition *** or polyhedral nickel crystallites were observed at higher ratio of SDS/CTAB while smaller oval grains with refined surface morphologies were obtained at lower ratio of SDS/CTAB *** addition,wt%of particles co-deposition was increased,and Vickers microhardness,wear and coefficient of friction of the electrodeposited composite coatings were improved at increased CTAB and decreased SDS contents in the electrolyte during electrodeposition process.

关键词： Ni-SiC-h/BN Composite coating Surfactant Microstructure Scratch Wear

Extraction and Purification of Depigmenting Agents from Chinese Plants

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Chemical Research in Chinese Universities 2006年第2期22卷 162-167页

作者： AHN So-young ROW Kyung-ho kim Eun-ki School of Chemical and Biological Engineering Center for Advanced Bioseparation Technology Inha University Nam-Ku Incheon 402-751 Korea

Depigmenting agents were solvent-extracted and purified by preparative and analytical HPLC from three Chinese plants; Chrysanthemum morifolium Ramat（ Xizang Caijuhua）, Rhodiola sachalinensis, and Terminalia chebula Retzius. Four fractions obtained from the ethyl ether layer of C. m. Rama and two fractions from the ethyl acetate layer of Rhodiola salientness show depigmenting effects. At 8 200, the ethyl acetate layers of Chrysanthemum morifolium Ramat, Rhodiola sachalinensis and the methanol extract of Terminalia chebula Retzius, can inhibit the melanin production of mouse B16 melanoma cells by 92%, 60% and 90%, respectively, whereas 46% inhibition was observed by commercially available depigmenting agents（arbutin）. These results show the potential of these three Chinese plants as a novel resource for depigmenting agents in the cosmetic industry.

关键词： Chrysanthemum Morifolium Ramat Rhodiola Sachalinensis Terminalia Chebula Retzius Melanin Inhibitory Effect HPLC

Mitochondrial Reactive Oxygen Species Elicit Acute and Chronic Itch via Transient Receptor Potential Canonical 3 Activation in Mice

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Neuroscience Bulletin 2022年第4期38卷 373-385页

作者： Seong-Ah kim Jun ho Jang Wheedong kim Pa Reum Lee Yong ho kim Hue Vang Kihwan Lee Seog Bae Oh Department of Neurobiology and Physiology School of Dentistry and Dental Research InstituteSeoul National UniversitySeoul 03080Republic of Korea Department of Brain and Cognitive Sciences College of Natural SciencesSeoul National UniversitySeoul 08826Republic of Korea Gachon Pain Center and Department of Physiology College of MedicineGachon UniversityIncheon 21999Republic of Korea Tooth-Periodontium Complex Medical Research Center School of DentistrySeoul National UniversitySeoul 03080Republic of Korea

Mitochondrial reactive oxygen species(mROS)that are overproduced by mitochondrial dysfunction are linked to pathological conditions including sensory ***,we explored whether mROS overproduction induces itch through transient receptor potential canonical 3(TRPC3),which is sensitive to *** injection of antimycin A(AA),a selective inhibitor of mitochondrial electron transport chain complex III for mROS overproduction,produced robust scratching behavior in naïve mice,which was suppressed by MitoTEMPO,a mitochondria-selective ROS scavenger,and Pyr10,a TRPC3-specific blocker,but not by blockers of TRPA1 or *** activated subsets of trigeminal ganglion neurons and also induced inward currents,which were blocked by MitoTEMPO and ***,dry skin-induced chronic scratching was relieved by MitoTEMPO and Pyr10,and also by resveratrol,an *** together,our results suggest that mROS elicit itch through TRPC3,which may underlie chronic itch,representing a potential therapeutic target for chronic itch.

关键词： Mitochondria Reactive oxygen species TRPC3 Itch Dry skin Trigeminal ganglia