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High-concentration dispersions of exfoliated MoS2 sheets stabilized by freeze-dried silk fibroin powder

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Nano Research 2016年第6期9卷 1709-1722页

作者： HeungBo sim JiYong Lee Byeongho Park Sun jun Kirn Shinill Kang ,WonHyoung Ryu Seong Chan jun School of Mechanical Engineering Yonsei University Seoul 120-749 Republic of Korea

Liquid-phase exfoliation （LPE） is an attractive method for the scaling-up of exfoliated MoS2 sheets compared to chemical vapor deposition and mechanical cleavage. However, the MoS2 nanosheet yield from LPE is too small for practical applications. We report a facile method for the scaling-up of exfoliated MoS2 nanosheets using freeze-dried silk fibroin powders. Compared to MoS2 dispersion in the absence of silk fibroin powder, sonicated MoS2 dispersions with silk fibroin powder （MoSJSilk dispersion） show noticeably higher exfoliated MoS2 nanosheet yields, with suspended MoS2 concentrations in MoS2/Silk dispersions sonicated for 2 and 5 h of 1.03 and 1.39 ***-1, respectively. The MoS2 concentration in the MoS2/Silk dispersion after centrifugation above 10,000 rpm is more than four times that without the silk fibroin. The size of the dispersed silk fibroin is controlled by the change of centrifugation rate, showing the removal of silk fibroin above tens of micrometers in size after centrifugation at 2,000 rpm. Size-controlled silk fibroin biomolecules combined with MoS2 nanosheets are expected to increase the practical use of such materials in fields related to tissue engineering, biosensors and electrochemical electrodes. Atomic force microscopy and Raman spectroscopy provide the height of the MoS2 nanosheets spin-cast from MoS2/Silk dispersions, showing thicknesses of 3--6 nm. X-ray photoelectron spectroscopy and X-ray diffraction indicate that the outermost surface layer of the hydrophobic MoS2 crystals interact with oxygen-containing functional groups that exist in the hydrophobic part of silk fibroins. The amphiphilic properties of silk fibroin combined with the MoS2 nanosheets stabilize dispersions by enhancing solvent-material interactions. The large quantities of exfoliated MoS2 nanosheets suspended in the as-synthesized dispersions can be utilized for the fabrication of vapor and electrochemical devices requiring high MoS2 nanosheets contents.

关键词： MoS2 nanosheet liquid-phase exfoliation freeze-dried silk fibroin powder amount of suspended MoB2 sheet stabilized dispersion

MXene-based hybrid materials for electrochemical and photoelectrochemical H_(2) generation

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Journal of Energy Chemistry 2024年第6期93卷 111-125,I0004页

作者： jun Young Kim Seung Hun Roh Chengkai Xia Uk sim jung Kyu Kim School of Material Science and Engineering North University of ChinaTaiyuan 030051China School of Chemical Engineering Sungkyunkwan University(SKKU)2066Seobu-roJangan-guSuwon 16419Republic of Korea Hydrogen Energy Technology Laboratory Korea Institute of Energy Technology(KENTECH)NajuJeollanamdo 58330Republic of Korea SKKU Advanced Institute of Nano Technology(SAINT) Sungkyunkwan University(SKKU)2066Seobu-roJangan-guSuwon 16419Republic of Korea

The conversion of solar energy to produce clean hydrogen fuel through water splitting is an emerging strategy for efficiently storing solar energy in the form of solar *** aligns with the increasing global demand for the development of an ideal energy alternative to fossil fuels that does not emit greenhouse ***(EC) and photoelectrochemical(PEC) water splitting technologies have garnered significant attention worldwide for advanced hydrogen solar fuel production in recent *** achieve sustainable green H_(2) production,it is essential to create efficient catalyst materials that are low-cost and can replace expensive noble metal-based *** characteristics make them an ideal catalyst material for the ***-dimensional MXenes with M_(n+1)X_(n) structure have been identified as a promising option for EC and PEC water splitting due to their superior hydrophilicity,metal-like conductivity,large surface area,and adjustable surface ***,we present a summary of recent advancements in the synthesis and performance enhancement methods for MXene hybrid materials in hydrogen production through EC and PEC water ***,we examine the challenges and insights associated with the rational design of MXene-based hybrid materials to facilitate efficient water splitting for sustainable solar fuel production.

关键词： MXene Hybrid materials EC PEC HER OER Water splitting

A comparative study of interface reconstruction algorithms in molten metal flow

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China Foundry 2013年第1期10卷 50-56页

作者： Young-sim Choi jun-Ho Hong Ho-Young Hwang e-Design Center Korea Institute of Industrial TechnologyIncheon 406-840Korea

In the present research,two numerical schemes for improving the accuracy of the solution in the flow simulation of molten metal were *** method is the Piecewise Linear Interface Calculation(PLIC) method and the other is the Donor-Acceptor(D-A) *** verify the module of the interface reconstruction algorithms,simple problems were *** these validations,the accuracy and efficiency of these two methods were compared by simulating various real *** the numerical simulation of free surface flow,it is possible for the PLIC method to track very accurately the interface between *** PLIC method,however,has the weak point in that a lot of computational time is required,though it shows the more accurate interface *** Donor-Acceptor method has enough effectiveness in the macro-observation of a mold filling sequence though it shows inferior ***,for the problems that need the accurate solution,PLIC is more appropriate than *** accuracy may cause less efficiency in numerical *** method between D-A method and PLIC method should be chosen depends on the product.

关键词： interface reconstruction DA PLIC molten metal flow accuracy volume of fluid method

Diagnosis parameters of mold filling pattern for optimization of a casting system

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China Foundry 2012年第4期9卷 376-380页

作者： jun-Ho Hong Young-sim Choi Ho-Young Hwang e-Design Center Korea Institute of Industrial Technology e-Design Center Korea Institute of Industrial TechnologyIncheonKorea

For optimal design of a gating system,the setting of diagnosis parameters is very *** this study,the permanent mold casting process was selected because most of the other casting processes have more complicated factors that influence the mold filling pattern compared to the permanent mold casting process,such as the surface roughness of mold,gas generation from the mold wash and binder of sand mold,and the gas permeability through a sand mold,*** diagnosis parameters(flow rate difference and arrival time difference) of molten metal flow pattern in the numerical simulation are suggested for design of an optimum casting system with a permanent *** results show that the arrival time difference can be used as one important diagnosis parameter of the complexity of the runner system and its usefulness has been verified via making aluminum parts using permanent mold casting(Fig.9).

关键词： mold filling pattern optimum casting system diagnosis parameter permanent mold casting process

Accumulation of poly(adenosine diphosphate-ribose)by sustained supply of calcium inducing mitochondrial stress in pancreatic cancer cells

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World Journal of Gastroenterology 2022年第27期28卷 3422-3434页

作者： Keun-Yeong Jeong Jae jun sim Minhee Park Hwan Mook Kim Research and Development Metimedi PharmaceuticalsIncheon 22006South Korea

BACKGROUND The biochemical phenomenon defined as poly adenosine diphosphate(ADP)-ribosylation(PARylation)is essential for the progression of pancreatic ***,the excessive accumulation of poly ADP-ribose(PAR)induces apoptosis-inducing factor(AIF)release from mitochondria and energy deprivation resulting in the caspase-independent death of cancer *** To investigate whether sustained calcium supply could induce an anticancer effect on pancreatic cancer by PAR *** Two pancreatic cancer cell lines,AsPC-1 and CFPAC-1 were used for the *** influx and mitochondrial reactive oxygen species(ROS)were observed by fluorescence *** in enzyme levels,as well as PAR accumulation and energy metabolism,were measured using assay ***-dependent cell death was investigated followed by confirming in vivo anticancer effects by sustained calcium *** Mitochondrial ROS levels were elevated with increasing calcium influx into pancreatic cancer ***,excess PAR accumulation,decreased PAR glycohydrolase and ADP-ribosyl hydrolase 3 levels,and energy deprivation were *** vitro and in vivo antitumor effects were confirmed to accompany elevated AIF *** This study visualized the potential anticancer effects of excessive PAR accumulation by sustained calcium supply on pancreatic cancer,however elucidating a clear mode of action remains a challenge,and it should be accompanied by further studies to assess its potential for clinical application.

关键词： Pancreatic cancer Calcium Reactive oxygen species Poly adenosine diphosphate-ribose Poly adenosine diphosphate-ribosylation Poly adenosine diphosphate-ribose polymerase Apoptosis-inducing factor Nicotinamide adenine dinucleotide Anticancer effect

A study on effects of ceramic foam filter on flow aspect through water modeling experiment

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China Foundry 2017年第3期14卷 216-225页

作者： Ho-Young Hwang Cheol-Hee Nam Young-sim Choi jun-Ho Hong Xun Sun Cyber Manufacturing Process Group Korea Institute of Industrial Technology Incheon 21999 South Korea Department of Robotics and Virtual Engineering Korea University of Science and Technology Daejeon 34113 South Korea Materials Science and Engineering Kyoto University Kyoto 606-8501 Japan Shenyang Research Institute of Foundry Shenyang 110022 China

Casting defects that are closely related to entrapped air bubbles and metallic oxides occur very frequently in the sand mold casting process. Many researchers have shown that these defects can be reduced by adopting an appropriate gating system design. However, it is difficult for field engineers to identify a specific gating system that is more appropriate for their products. In this study, we tried to draw a comparison between two gating system designs with and without a ceramic foam filter. The ceramic foam filter was added to the horizontal runner just after the down sprue to prevent air bubble generation and reduce turbulence without a change of gating system design. The water modeling experiment was conducted with four different amounts of the initial volumes of water in the reservoir to verify the effects of initial pouring velocity. The results of the experiment applying the filter showed remarkably changed flow characteristics. The use of the filter was found to convert the flow pattern of water in the desired direction. The ceramic foam filter performed well to reduce flow velocity and stabilize the water *** flow pattern without a filter can be improved significantly even with the the use of just a 10 PPI irregular filter. Although the study confirmed that use of the filter may change the flow characteristics, it needs to be noted that the use of the ceramic filter alone cannot solve all the problems caused by a poorly designed gating system.

关键词： ceramic foam filter sprue gating system design sand mold casting casting defect

Genome-wide association study identifies QTL for eight fruit traits in cultivated tomato (Solanum lycopersicum L.)

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Horticulture Research 2021年第1期8卷 2698-2707页

作者： Minkyung Kim Thuy Tien Phan Nguyen Joon-Hyung Ahn Gi-jun Kim Sung-Chur sim Department of Bioresources Engineering Sejong UniversitySeoulRepublic of Korea Asia Seed R&D center IcheonRepublic of Korea Plant Engineering Research Institute Sejong UniversitySeoulRepublic of Korea

Genome-wide association study(GWAS)is effective in identifying favorable alleles for traits of interest with high mapping resolution in crop *** this study,we conducted GWAS to explore quantitative trait loci(QTL)for eight fruit traits using 162 tomato accessions with diverse genetic *** eight traits included fruit weight,fruit width,fruit height,fruit shape index,pericarp thickness,locule number,fruit firmness,and *** variations of these traits in the tomato collection were evaluated with three replicates in field trials over three *** filtered 34,550 confident SNPs from the 51K Axiom®tomato array based on5%of minor allele frequency for association *** 162 tomato accessions were divided into seven clusters and their membership coefficients were used to account for population structure along with a kinship *** identify marker-trait associations(MTAs),four phenotypic data sets representing each of three years and combined were independently analyzed in the multilocus mixed model(MLMM).A total of 30 significant MTAs was detected over data sets for eight fruit traits at P<*** number of MTA per trait ranged from one(brix)to seven(fruit weight and fruit width).Two SNP markers on chromosomes 1 and 2 were significantly associated with multiple traits,suggesting pleiotropic effects of ***,16 of 30 MTAs suggest potential novel QTL for eight fruit *** results facilitate genetic dissection of tomato fruit traits and provide a useful resource to develop molecular tools for improving fruit traits via marker-assisted selection and genomic selection in tomato breeding programs.

关键词： breeding traits membership

Dynamic Behavior of Bump Foils with Thermal Effect in Air Foil Bearings

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Dynamic Behavior of Bump Foils with Thermal Effect in Air Fo...

Pretreated Oenan the Javanica extract increases anti-inflammatory cytokines, attenuates gliosis, and protects hippocampal neurons following transient global cerebral ischemia in gerbils

第9届全国转子动力学学术讨论会ROTDYN'2010

作者： Yong-Bok Lee jun-hyeon Jo Kyu Ho sim Yoon-Chul Rhim Energymechanics Center Korea Institute of Science and Technology P.O.Box 131CheongryangSeoulKorea130-650 Yonsei University 134 Sinchon-dongSeodaemun-guSeoulRepublic of Korea 120-749

An air foil bearing is composed of a bump foil,top foil and bearing *** bump foil provides high stiffness and damping. In this study,the dynamics of the bump foil is investigated by FEM(Finite element method)and an experimental *** strain-stress method and triangle elements were used for FEM *** thermal effect was considered by property of foils’ high temperature material *** measure stiffness and damping coefficients of the bump foil considering thermal effects,the high temperature bump foil test setup was *** results of comparing FEM analysis and experiments show that the frictions between the bump foil-the top foil and the bump foil-the bearing housing,and high temperature affect to stiffness and damping coefficients of bump foils.

关键词： Air foil bearing High temperature thermal effect Dynamic coefficient

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Neural Regeneration Research 2019年第9期14卷 1536-1543页

作者： Joon Ha Park In Hye Kim Ji hyeon Ahn YooHun Noh Sung-Su Kim Tae-Kyeong Lee Jae-Chul Lee Bich-Na Shin Tae Heung sim Hyun Sam Lee Jeong Hwi Cho In Koo Hwang Il jun Kang Jong Dai Kim Moo-Ho Won Department of Biomedical Science and Research Institute for Bioscience and Biotechnology Hallym UniversityChuncheonGangwonRepublic of Korea Famenity Company GwacheonGeyonggiRepublic of Korea Department of Neurobiology School of MedicineKangwon National UniversityChuncheonGangwonRepublic of Korea Danchunok Company ChuncheonGangwonRepublic of Korea Department of Histology College of Veterinary MedicineChonbuk National UniversityIksanJeollabuk.doRepublic of Korea Department of Anatomy and Cell Biology College of Veterinary Medicineand Research Institute for Veterinary ScienceSeoul National UniversitySeoulRepublic of Korea Department of Food Science and Nutrition Hallym UniversityChuncheonGangwonRepublic of Korea Division of Food Biotechnology School of BiotechnologyKangwon National UniversityChuncheonGangwonRepublic of Korea

Recently,we have reported that Oenanthe javanica extract(OJE)displays strong neuroprotective effect against ischemic damage after transient global cerebral ***,neuroprotective mechanisms of OJE have not been fully ***,this study investigated the neuroprotection of OJE in the hippocampal CA1 area and its anti-inflammatory activity in gerbils subjected to 5 minutes of transient global cerebral *** treated the animals by intragastrical injection of OJE(100 and 200 mg/kg)once daily for 1 week prior to transient global cerebral *** of OJE was observed by immunohistochemistry for neuronal nuclear antigen and histofluorescence staining for Fluoro-Jade *** of glial fibrillary acidic protein and ionized calcium-binding adapter molecule 1 was done for astrocytosis and microgliosis,*** investigate the neuroprotective mechanisms of OJE,we performed immunohistochemistry of tumor necrosis factor-alpha and interleukin-2 for pro-inflammatory function and interleukin-4 and interleukin-13 for anti-inflammatory *** we treated the animals by intragastrical administration of 200 mg/kg of OJE,hippocampal CA1 pyramidal neurons were protected from transient global cerebral ischemia and cerebral ischemia-induced gliosis was inhibited in the ischemic hippocampal CA1 *** also found that interleukin-4 and-13 immunoreactivities were significantly increased in pyramidal neurons of the ischemic CA1 area after OJE pretreatment,and the increased immunoreactivities were sustained in the CA1 pyramidal neurons after transient global cerebral ***,OJE pretreatment did not increase interleukin-2 and tumor necrosis factor-alpha immunoreactivities in the CA1 pyramidal *** findings suggest that pretreatment with OJE can protect neurons and attenuate gliosis from transient global cerebral ischemia via increasing expressions of interleukin-4 *** experimental plan of this study was rev

关键词： Oenanthe javanica extract transient global cerebral ischemia hippocampus ischemic damage cerebral ischemia neuroprotection glial activation pro-inflammatory cytokines anti-inflammatory cytokines inflammation neural regeneration