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Growth of silicon nanowires in aqueous solution under atmospheric pressure

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Nano Research 2014年第6期7卷 898-902页

作者： Nae-Man park Chel-jong Choi Components and Materials Laboratory Electronics and Telecommunications Research Institute (ETRI) 161 Gajeong-dong Yuseong-gu Daejeon 305-700 Republic of Korea School of Semiconductor and Chemical Engineering Semiconductor Physics Research Center Chonbuk National University 664-14 Deokjin-dong Deokjin-gu Jeonju 561-756 Republic of Korea

A new method for growing silicon nanowires is presented. They were grown in an aqueous solution at a temperature of 85 °C under atmospheric pressure by using sodium methylsiliconate as a water-soluble silicon precursor. The structure, morphology, and composition of the as-grown nanowires were characterized by scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectrometry. It was also confirmed by X-ray powder diffraction and Raman spectroscopy that the silicon nanowire has a hexagonal structure. It was possible to grow the crystalline silicon nanowires at low temperature under atmospheric pressure because potassium iodide, which was used as a gold etchant, sufficiently increased the surface energy and reactivity of gold as a metal catalyst for the reaction of the Si precursor even at low temperature.

关键词：硅纳米线溶液生长大气压水溶液扫描电子显微镜透射电子显微镜粉末X射线衍射六边形结构

Enhanced KOCED Routing Protocol with K-means Algorithm

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Computers, Materials & Continua 2021年第6期67卷 4019-4037页

作者： SeaYoung park jong-Yong Lee Daesung Lee Department of Plasma Bioscience and Display KwangWoon University Graduate SchoolSeoul01897Korea Ingenium College of Liberal Arts KwangWoon UniversitySeoulKorea Department of Computer Engineering Catholic University of PusanBusanKorea

Replacing or recharging batteries in the sensor nodes of a wireless sensor network(WSN)is a significant ***,efficient power utilization by sensors is a critical requirement,and it is closely related to the life span of the *** a sensor node consumes all its energy,it will no longer function ***,various protocols have been proposed to minimize the energy consumption of sensors and thus prolong the network ***,clustering algorithms combined with artificial intelligence have been proposed for this *** particular,various protocols employ the K-means clustering algorithm,which is a machine learning *** number of clustering configurations required by the K-means clustering algorithm is greater than that required by the hierarchical ***,the selection of the cluster heads considers only the residual energy of the nodes without accounting for the transmission distance to the base *** terms of energy consumption,the residual energy of each node,the transmission distance,the cluster head location,and the central relative position within the cluster should be considered *** this paper,we propose the KOCED(K-means with Optimal clustering for WSN considering Centrality,Energy,and Distance)protocol,which considers the residual energy of nodes as well as the distances to the central point of the cluster and the base station.A performance comparison shows that the KOCED protocol outperforms the LEACH protocol by 259%(223 rounds)for first node dead(FND)and 164%(280 rounds)with 80%alive nodes.

关键词： WSN routing protocol K-means K-optimal LEACH KCE KOCED

Analysis of the effectiveness of cognitive rehabilitation for patients with chronic mental illness:A meta-analysis

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World Journal of Clinical Cases 2023年第32期11卷 7822-7832页

作者： jong-Sik Jang Seri Oh Geonwoo Kim Narae Lee Hyesu Song Jihye park Yushin Lee Minji Kim Mihwa Kwon Department of Occupational Therapy Kangwon National UniversitySamcheok 25949South Korea Department of Occupatioanl Therapy Kangwon National University Graduate SchoolSamcheok 25949South Korea Department of Occupational Therapy U1 UniversityChung-Cheong Bukdo 25949South Korea Department of Occupation Therapy Dongnam Health UniversityGyeonggi-do 16328South Korea

BACKGROUND People suffering from chronic mental illness are sensitive to stressful stimuli,lack coping skills,and have low self-esteem due to problems such as social *** also experience depression,isolation,fear,and *** to cognitive dysfunction,people suffering from chronic mental illness have inadequate cognitive processes that lead to distorted *** To confirm the effectiveness of cognitive rehabilitation therapy in improving cognitive function and alleviating behavioral and psychological symptoms in patients with chronic mental illness,and to identify the cognitive function that had the main *** The quality of the studies was evaluated using the Assessment of Multiple Systematic Reviews criteria,and data published from 2011 to December 2022 were searched using PubMed,Cochrane,RISS,KISS,and *** keywords used in the search were“mental illness,”“cognitive rehabilitation,”“cognition,”and“mental.”A meta-analysis was conducted on the 12 selected *** The level of evidence for the 12 documents was that of a randomized experimental *** types in cognitive rehabilitation can be divided into cognitive behavior,cognitive training,cognitive rehabilitation,and computerized cognitive *** of the studies were on schizophrenia,and the measurement areas were cognitive functions(e.g.,concentration,memory,and executive function)as well as depression,sociability,and quality of *** a result of the meta-analysis of each variable,the effect size for cognitive rehabilitation treatment was in the following order:Sociability,memory,concentration,executive function,quality of life,and ***,sociability and memory exhibited significant *** Cognitive rehabilitation aids cognitive function and sociability in patients with chronic mental illness and can be used as evidence for cognitive rehabilitation in mental health and occupational therapy.

关键词： Cognitive function Mental illness Cognitive rehabilitation Cognitive training Cognitive therapy Schizophrenia Occupational therapy

Comparison of electrochemical properties of atmospheric pressure plasma coatings for Al_2O_3-3TiO_2 and CoNiCrAlY in sea water

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中国有色金属学会会刊：英文版 2012年第S3期22卷 745-752页

作者： Seong-jong KIM Seong-kweon KIM Jae-cheul park Division of Marine Engineering Mokpo Maritime University Department of Electronic IT Media Engineering Institue of TechnologySeoul National University of Science and Technology New Growth Technical Support Team Green and Industrial Technology CenterKorean Register of Shipping

To improve the durability of underwater rotating products,the corrosion characteristics in harsh marine environment were evaluated through various electrochemical experiments on the Al2O3-3TiO2 and CoNiCrAlY coating layers by atmospheric pressure plasma spray coating *** evaluating the corrosion resistance of these materials,their applicability to environmentally friendly power generation equipment such as blades of tidal current turbines was *** to the Tafel analysis for micro-areas including the coating layer,the coating/metal interlayer and the base metal,the Al2O3-3TiO2 coating layer and the CoNiCrAlY coating layer show markedly lower corrosion current density than the base *** corrosion current density of the CoNiCrAlY coating layer (9.75316×10-8A/cm2) is about 1.6 times more than that of the Al2O3-3TiO2 coating layer (6.13139×10-8A/cm2).

关键词： Al2O3-3TiO2 coating layer CoNiCrAlY coating layer underwater rotating products marine environment corrosion characteristics atmospheric pressure plasma spray

Numerical analysis of vortex core phenomenon during draining from cylinder tank for various initial swirling speeds and various tank and drain port sizes

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Journal of Hydrodynamics 2013年第2期25卷 183-195页

作者： SOHN Chang Hyun SON jong Hyeon park Il Seouk School of Mechanical Engineering Kyungpook National University

A dimple appears on a free surface while rotating a cylinder tank filled with liquid. The dimple starts to concentrically deeper to a drain port at the bottom center of the tank. Over time, the dimple penetrates the drain port, a free surface forms a long and slender string shape in the tank, and a so-called vortexing （air core） phenomenon occurs. The generation of a vortex core depends on the size of the tank and drain port, and on the properties of the liquid in the tank. In this study, the liquid level and the time at which the vortex core is initially generated are numerically investigated using different values of tank diameter, drain port diameter, and ini- tial tank rotational speeds. Instead of a full three-dimensional analysis, a two-dimensional axisymmetric simulation is conducted. The momentum conservation equation in the circumferential direction is additionally solved in the two-dimensional mesh system. Several non-dimensional variables are created： the ratio of the air core generation distance and tank diameter, the diameter ratio of the tank and drain port, the rotational Reynolds number, the rotational Froude number, and the rotational Weber number. Finally, the non-dimensional air core generation distance is correlated with the other non-dimensional parameters.

关键词： air core vortex core dip penetration vortexing draining

Influence of Bi addition on dynamic recrystallization and precipitation behaviors during hot extrusion of pure Mg

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Journal of Materials Science & Technology 2020年第9期44卷 62-75页

作者： jongbin Go jong Un Lee Hui Yu Sung Hyuk park School of Materials Science and Engineering Kyungpook National UniversityDaegu41566Republic of Korea School of Materials Science and Engineering Hebei University of TechnologyTianjin300130China

Low material cost and high extrudability for ensuring price competitiveness with Al alloys,as well as excellent mechanical properties,are essential for expanding the application range of Mg *** is a promising alloying element for developing extruded Mg alloys that satisfy such *** is inexpensive,exhibits a high solubility limit,and forms a thermally stable Mg3Bi2 phase,which improves the commercial viability and enables the high-speed extrusion of Mg–Bi *** this study,the effects of Bi addition on the dynamic recrystallization(DRX)and dynamic precipitation behaviors during hot extrusion of a pure Mg and the resultant microstructure and mechanical properties of the extruded materials were *** addition of 6 wt%and 9 wt%Bi to a pure Mg yielded numerous fine Mg3Bi2 precipitates during the early stage of hot ***,the area fraction of dynamic recrystallized(DRXed)grains decreased because of DRX-behavior suppression by the Zener pinning ***,the DRXed grain size was substantially reduced through the grain-boundary pinning *** size and number of undissolved Mg3Bi2 particles in the homogenized billets increased when the Bi content was increased,which resulted in increased DRX fractions owing to the enhanced levels of particle stimulated *** addition yielded considerable strength improvement of the extruded pure ***,the extruded Mg–Bi binary materials were less ductile than the extruded pure Mg *** lower ductility resulted from the cracking at twins formed in the coarse unDRXed grains of the Mg-6Bi material and the cracking at large undissolved Mg3Bi2 particles in the Mg-9Bi material.

关键词： Magnesium Bi addition Extrusion Recrystallization Precipitation

A dynamic infiltration technique to synthesize nanolayered cathodes for high performance and robust solid oxide fuel cells

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Journal of Energy Chemistry 2022年第7期31卷 201-210,I0006页

作者： Saeed Ur Rehman Ho-Seon Song Hye-Sung Kim Muhammad Haseeb Hassan Dong-Woo Joh Rak-Hyun Song Tak-Hyoung Lim jong-Eun Hong Seok-Joo park Seung-Bok Lee High Temperature Energy Conversion Laboratory Korea Institute of Energy Research152Gajeong-roYuseong-gu.Daejeon34129.Republic of Korea Department of Advanced Energy and System Engineering University of Science and Technology.217 Gajeong-ro.Yuseong-gu.Daejeon 34113.Republicof Korea

Solution infiltration is a popular technique for the surface modification of solid oxide fuel cell(SOFC)***,the synthesis of nanostructured SOFC cathodes by infiltration is a tedious process that often requires several infiltration and high temperature(≥500℃)calcination ***,fabricating large-area nanostructured cathodes via infiltration still requires serious ***,we propose a facile and scalable urea assisted ultrasonic spray infiltration technique for nanofabrication of SOFC *** is demonstrated that by using urea as a precipitating agent,the calcination after each infiltration cycle can be omitted and the next infiltration can be performed just after a drying step(≤100℃).Finally,the precipitates can be converted into a desired catalyst phase in single calcination thus,a nanostructured cathode can be fabricated in a much faster *** is also shown that the low calcination temperature of the cathode(≤900℃)can produce highly durable SOFC performance even without employing a Ce_(0.9)Gd_(0.1)O_(2)(GDC)diffusion barrier layer which provides the ease of SOFC *** coupling with an ultrasonic spray technique,the urea assisted infiltration can be scaled up for any desired cathode ***_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3) nanolayered cathode was fabricated and it was characterized by scanning electron microscope(SEM),X-ray diffraction(XRD),and transmission electron microscopy(TEM)*** showed the formation of a nanolayer cathode just after 5 cycles of the urea assisted infiltration while the XRD and TEM confirmed the phase and stoichiometric uniformity of the 100 nm cathode *** effectiveness of the newly developed technique was further verified by the stable operation of a GDC buffer layer free SOFC having an active cathode area of 25 cm^(2) during a 1200 h durability *** research outcomes propose urea assisted ultrasonic spray infiltration as a facile,scalable,and commercially viable method

关键词： Solid oxide fuel cell(SOFC) Cathode Infiltration Nanolayer Nanofabrication GDC barrier layer free SOFC

Impregnation approach for poly(vinylidene fluoride)/tin oxide nanotube composites with high tribological performance

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Journal of Materials Science & Technology 2020年第2期37卷 19-25页

作者： Min Su park Jin Kyu Kim Tong-Seok Han Jung Tae park jong Hak Kim Department of Chemical and Biomolecular Engineering Yonsei University50 Yonsei-roSeodaemun-guSeoul03722Korea Department of Civil and Environmental Engineering Yonsei University50 Yonsei-roSeodaemun-guSeoul03722Korea Department of Chemical Engineering Konkuk University120 Neungdong-roGwangjin-guSeoul05029Korea

We report a composite material with the high tribological performance,which consists of onedimensional SnO2 nanotubes(ST)and a high molecular weight poly(vinylidene fluoride)(PVDF)matrix in terms of *** of PVDF in N,N-dimethylformamide(DMF)resulted in a facile penetration of PVDF into the inner hollow voids of ST,leading to the close *** between PVDF and ST results in a beneficial effect on the chain arrangement of PVDF,providing anα-phase with better tribological *** ST incorporation,the friction coefficient decreased by 85.0%to 0.408,and the specific wear rate decreased by 69.1%to 0.412,demonstrating the pivotal role of ST as a self-lubricating material due to a large interactive area and PVDF chain rearrangement.

关键词： SnO2 nanotube Composite Friction coefficient Wear rate

Speed vernalization to accelerate generation advance in winter cereal crops

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Molecular Plant 2022年第8期15卷 1300-1309页

作者： Jin-Kyung Cha Kathryn O'Connor Samir Alahmad jong-Hee Lee Eric Dinglasan Hyeonjin park So-Myeong Lee Dominique Hirsz Soon-Wook Kwon Youngho Kwon Kyeong-Min Kim jong-Min Ko Lee T.Hickey Dongjin Shin Laura E.Dixon National Institute of Crop Science RDAMiryang 50424Korea School of Biology Faculty of Biological SciencesUniversity of LeedsLeeds LS29JTUK Queensland Alliance for Agriculture and Food Innovation The University of QueenslandSt.LuciaQLDAustralia Department of Plant Bioscience Pusan National UniversityMiryang 60463Korea

There are many challenges facing the development of high-yielding,nutritious crops for future *** limiting factor is generation time,which prolongs research and plant breeding *** advances in speed breeding protocols have dramatically reduced generation time for many short-day and long-day species by optimizing lightand temperature conditions during plant ***,winter crops with a vernalization requirement stillrequire upto 6-10weeks in low-temperature conditions before thetransition to ***,we tested a suite of environmental conditions and protocols to investigate whether the vernalization process can be *** identified a vernalization method consisting of exposing seeds at the soil surface to an extended photoperiod of 22 h day:2 h night at 10°C with transfer to speed breeding conditions that dramatically reduces generation time in both winter wheat(Triticum aestivum)and winter barley(Hordeum vulgare).Implementation of the speedvernalization protocolfollowed byspeedbreedingallowed the completion ofuptofivegenerations per yearforwinter wheat or barley,whereas only two generations can be typically completed under standard vernalization and plant growth *** speed vernalization protocol developed in this study has great potential to accelerate biological research and breeding outcomes for winter crops.

关键词： speed breeding photoperiod temperature wheat barley breeding