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Journal of Materials Science & Technology 2020年第5期40卷 176-184页

作者： Vellaichamy Balakumar Hyungjoo Kim ji.Won Ryu Ramalingam Manivannan young-A son Department of Advanced Organic Materials Engineering Chungnam National University220 Gung-dongYuseong-guDaejeon305-764South Korea

In this work,a simple synthesis of sulfur doped graphitic carbon nitride(S-g-C3N4)act as a support cum stabilizers for gold nanoparticles(Au)and its was characterized by UV–vis and XRD to measure the absorbance and crystallinity,*** functional group and morphology of the samples were identified using FT-IR and ***,the Au@S-g-C3N4 nanocatalyst exhibits good catalytic performance and stability in the reduction of hazardous 4-nitrophenol(NP)compared to S-g-C3N4 using Na ***,the Au@S-g-C3N4 nanocomposite holds a good catalytic efficiency(near 100%)achieved by within 5 *** highest catalytic reduction of NP is due to the synergistic effect of Au nanoparticles decorated on *** fast electron transfer reduction mechanism was elucidated and *** reusability and stability of the developed nanocomposites were also observed in consecutive reduction *** filtering and catalyzing device was used for the direct conversion of NP polluted *** method can open a new avenue for the metal nanoparticles based carbon materials heterogeneous catalyst and its reduction of toxic contaminants.

关键词： Gold nanoparticles S-doped g-C3N4 Catalytic reduction 4-nitrophenol

Risks of non-conservative design according to ASME B31.1 for high-temperature piping subjected to long-term operation in the creep range

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Nuclear Science and Techniques 2019年第5期30卷 59-69页

作者： Hyeong-Yeon Lee Seok-Kwon son Min-Gu Won ji.young Jeong Korea Atomic Energy Research Institute National Fusion Research Institute School of Mechanical Engineering Sungkyunkwan University

This study investigates the risks of non-conservative piping design according to ASME B31.1 for hightemperature piping subjected to long-term operation at high temperature in a creep regime based on a sensitivity analysis of the hold time. Design evaluations of hightemperature piping were conducted over a range of hold times in the creep regime according to ASME B31.1,which implicitly considers the creep effects, and the French high-temperature design code of the RCC-MRx, which explicitly considers the creep effects. Conservatisms were quantified among the codes in terms of the hold times. In the case of B31.1, the design evaluation results do not change depending on the hold time at high temperature,whereas in the case of RCC-MRx, they do. It was shown that the design limits of RCC-MRx were exceeded when the hold time exceeded certain values, whereas those of B31.1 were satisfied regardless of the hold times. Thus, the design evaluations according to B31.1 did not consistently yield conservative results and might lead to non-conservative results in the case of long-term operations in the creep range.

关键词： ASME B31.1 Creep Hold time Hightemperature piping RCC-MRx Sensitivity analysis

Synapsing with NG2 cells(polydendrocytes),unappreciated barrier to axon regeneration?

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Neural Regeneration Research 2015年第3期10卷 346-348页

作者： young-ji. son Shriners Hospitals Pediatric Research Center and Department of Anatomy and Cell Biology Temple University School of Medicine

Have you heard of NG2 cells or NG2 glia or polydendro- cytes~. These are new names for the precursor cells that used to be referred to as oligodendrocyte precursor cells （OPCs）, which become the oligodendrocytes that myelinate central nervous system （CNS） axons. Evidence suggests, however, that they have other functions, besides differentiating into oligodendrocytes. Most notably, the OPCs/NG2 cells are uni- formly distributed in grey matter as well as in white matter, which matches poorly with the distribution of myelinating oligodendrocytes. Furthermore, not every NG2 cell is fated to become an oligodendrocyte. Hence the term OPC can be fairly applied only when discussing the role of these cells in the oligodendrocyte lineage.

关键词： NG cell Synapsing with NG2 cells polydendrocytes unappreciated barrier to axon regeneration

The Immersed Interface Hybridized Difference Method for Parabolic Interface Problems

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Numerical Mathematics(Theory,Methods and Applications) 2022年第2期15卷 336-359页

作者： youngmok Jeon son-young Yi Department of Mathematics Ajou UniversitySuwon 16499Republic of Korea Department of Mathematical Sciences The University of Texas at El PasoEl PasoTX 79968USA

We propose several immersed interface hybridized difference methods(IHDMs),combined with the Crank-Nicolson time-stepping scheme,for parabolic interface *** IHDM is the same as the hybrid difference method away from the interface cells,but the finite difference operators on the interface cells are modified tomaintain the same accuracy throughout the entire *** themodification process,we consider virtual extensions of two sub-solutions in the interface cells in such a way that they satisfy certain jump equations between *** propose several different sets of jump equations and their resulting discrete methods for one-and two-dimensional *** numerical results are presented to demonstrate the accuracy and robustness of the proposed methods.

关键词： Parabolic interface problem hybrid difference method immersed interface

Effects of nanopores and sulfur doping on hierarchically bunched carbon fibers to protect lithium metal anode

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Carbon Energy 2021年第5期3卷 784-794页

作者： ji.In Jung Sunwoo Park son Ha Se Youn Cho Hyoung-Joon ji. young Soo Yun Program in Environmental and Polymer Engineering Inha UniversityIncheonSouth Korea KU-KIST Graduate School of Converging Science and Technology Korea UniversitySeoulSouth Korea Carbon Composite Materials Research Center Korea Institute of Science and TechnologyWanju-gunJeollabuk-doSouth Korea Department of Polymer Science and Engineering Inha UniversityIncheonSouth Korea Department of Integrative Energy Engineering Korea UniversitySeoulSouth Korea

Studies on three-dimensional structured carbon templates have focused on how to guide homogeneous lithium metal nucleation and growth for lithium metal anodes(LMAs).However,there is still insufficient evidence for a key factor to achieve their high electrochemical ***,the effects of nanopores and sulfur doping on carbon-based nanoporous host(CNH)electrode materials for LMAs were investigated using natural polymer-derived *** pore-filling behaviors of lithium metal in the nanopores of the CNH electrode materials were first observed by ex situ scanning electron microscopy analysis,where the protective lithium metal nucleation and growth process led to significantly high Coulombic efficiency(CE)of~99.4%and stable 600 *** addition,a comparison study of CNH and sulfurdoped CNH(S-CNH)electrodes,which differ only in the presence or absence of sulfur,revealed that sulfur doping can cause lower electrochemical series resistance,higher CE value,and better cycling stability in a wide range of current densities and number of ***,S-CNH-based LMAs showed high electrochemical performance in full-cell Li-S battery tests using a sulfur copolymer cathode,where a high energy density of 1370Wh kgelectrode−1 and an excellent power density of 4120Wkgelectrode−1 were obtained.

关键词： carbon template Li-S batteries lithium metal anode lithium metal batteries nanoporous carbon sulfur doping

A facile synthesis of hierarchical Sn3O4 nanostructures in an acidic aqueous solution and their strong visible- light-driven photocatalytic activity

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Nano Research 2015年第11期8卷 3553-3561页

作者： Hui song Su-young son Seul Ki Kim Gun young Jung School of Materials Science and Engineering Gwangju Institute of Science and Technology (GIST) Gwangju 500-712 Republic of Korea Carbon Convergence Materials Research Center Institute of Advanced Composite Materials Korea Institute of Science and Technology (KIST) Jeollabuk-do 565-905 Republic of Korea

Hierarchical tin（Ⅲ） oxide, Sn3O4, nanospheres were synthesized via hydrothermal reaction under strongly acidic ambient conditions. The morphology of Sn3O4 varied with decreasing pH. The prickly SnaO4 nanospheres changed into SnaO4 nanospheres covered with single-crystalline nanoplates having a high BET surface area of ca. 55.05 m^2·g^-1 and a band gap of ca. 2.25 eV. Small amounts （0.05 g） of the hierarchical Sn3O4 nanostructures completely decomposed a 30% methyl orange （MO） solution in 100 mL deionized water within 15 min under one sun condition （UV ＋ visible light）. The Sn3O4 photocatalyst exhibited a fast decomposition rate of 1.73 ×10^-1 min^-1, which is a 90.86% enhancement relative to that of the commercially available P25 photocatalyst. The high photocatalytic activity of the hierarchical Sn3O4 nanostructures is attributed to its ability to absorb visible light and its high surface-to-volume ratio.

关键词： Sn3O4 hierarchical structure hydrothermal morphology engineering photocatalyst

Fast ethylamine gas sensing based on intermolecular charge-transfer complexation

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Chinese Chemical Letters 2012年第4期23卷 484-487页

作者： Eun Mi Lee Seon young Gwon young A son Sung Hoon Kim BK21 FTIT Department of Advanced Organic Materials and Textile System EngineeringChungnam National UniversityDaejeon 305-764Republic of Korea Department of Textile System Engineering Kyungpook National UniversityDaegu 702-701 Republic of Korea School of Chemistry Science & Technology Zhanjiang Normal UniversityZhanjiang 524048China

We have investigated the fast ethylamine gas sensing of 2-chloro-3,5-dinitrobenzotrifluoride（CDBF） loaded poly（acrylonitrile） nanofiber based on an intermolecular charge-transfer *** response and recovery were ach... 详细信息

关键词： Ethylamine gas Fast gas sensing 2-Chloro-3 5-dinitrobenzotrifluoride(CDBF) Electrospinning PAN nanofiber Intermolecular charge-transfer(CT) complexation

Feasibility Study of R134a/R404a Cascade Heat Pump Cycle in Heat Pump Dryers with Electrical Heaters at Low Temperatures

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Journal of Thermal Science 2015年第5期24卷 463-467页

作者： ji.Woo Jeong young Lim Lee Dept. of Mechanical Engineering Kongju National University Dept. of Mechanical and Automotive Engineering Kongju National University

Heat pump cycles have been widely applied to dryers for their high efficiency. However, low–efficiency electrical heaters are often used during early drying stage for frozen foods or winter since a standard heat pump cycle cannot operate at low temperature. This study introduced cascade heat pumps replacing electrical heaters to improve dryer performance at low temperatures. Experiments were performed to examine changes in performance of the cascade heat pump dryers in relation to ambient temperature, low-stage cycle mass flow rate, and high-stage cycle mass flow rate. The results showed a significant improvement in low-temperature dryer performance with the introduction of cascade heat pump cycles.

关键词： Cascade cycle R134a/R404a Heat pump dryer COP Energy efficiency

Two-stage dynamic recrystallization and texture evolution in Al-7Mg alloy during hot torsion

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1900-1911页

作者： Kwang Tae son Chang Hee Cho Myoung Gyun Kim ji.Woon Lee School of Mechanical Industrialand Manufacturing EngineeringOregon State UniversityCorvallis OR 97331USA Department of Materials Science Engineering Northwestern UniversityEvanston IL 60208USA Research Institute of Industrial Science and Technology(RIST) Pohang 37673Rep.of Korea Division of Advanced Materials Engineering Kongju National UniversityCheonan 31080Rep.of Korea Center for Advanced Materials and Parts of Powders Kongju National UniversityCheonan 31080Rep.of Korea

Hot torsion tests were performed on the Al-7Mg alloy at the temperature ranging from 300 to 500℃ and strain rates between 0.05 and 5 s^(-1) to explore the progressive dynamic recrystallization(DRX)and texture *** DRX behavior of the alloy manifested two distinct stages:Stage 1 at strain of≤2 and Stage 2 at strains of≥*** Stage 1,there was a slight increase in the DRXed grain fraction(X_(DRX))with predominance of discontinuous DRX(DDRX),followed by a modest change in X_(DRX) until the transition to Stage *** 2 was marked by an accelerated rate of DRX,culminating in a substantial final X_(DRX) of~*** backscattered diffraction(EBSD)analysis on a sample in Stage 2 revealed that continuous DRX(CDRX)predominantly occurred within the(121)[001]grains,whereas the(111)[110]grains underwent a geometric DRX(GDRX)evolution without a noticeable sub-grain ***,a modified Avrami’s DRX kinetics model was utilized to predict the microstructural refinement in the Al-7Mg alloy during the DRX *** this kinetics model did not accurately capture the DDRX behavior in Stage 1,it effectively simulated the DRX rate in Stage *** texture index was employed to assess the evolution of the texture isotropy during hot-torsion test,demonstrating significant improvement(>75%)in texture randomness before the commencement of Stage *** initial texture evolution is attributed to the rotation of parent grains and the substructure evolution,rather than to an increase in X_(DRX).

关键词： Al-7Mg alloys hot deformation hot torsion tests dynamic recrystazlliation microstructure texture

Authentication masking code against DoS of T-MAC protocol

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Journal of Central South University 2013年第7期20卷 1889-1895页

作者： son young-ho HONG ji.-keun BAE Keun-sung Attached Institute of ETRI Division of Information & Communication Baekseok University School of Electrical Engineering & Computer Science Kyungpook National University

Security vulnerability of denial of service (DoS) in time out-medium access control (T-MAC) protocol was discussed and analysis of power consumption at each stage of T-MAC protocol was carried out. For power efficient authentication scheme which can provide reliability, efficiency, and security for a general T-MAC communication, a novel synchronization and authentication scheme using authentication masking code was proposed. Authentication data were repeated and masked by PN sequence. The simulation results show that the proposed approach can provide synchronization and authentication simultaneously for nodes in wireless sensor network (WSN). 63 bits AMC code gives above 99.97% synchronization detection and 93.98% authentication data detection probability in BER 0.031 7.

关键词： time out-medium access control (T-MAC) security vulnerability authentication synchronization authenticationmasking code