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Electrostabilized homogeneous dispersion of boron nitride nanotubes in wide-range of solvents achieved by surface polarity modulation through pyridine attachment

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Nano Research 2020年第2期13卷 344-352页

作者： Mi Se Chang Min-Sun Jang Sangsun Yang Jihun Yu Taehoon Kim Sedong Kim Hyomin Jeong chong rae park Jae Won Jeong Powder/Ceramic Research Division Korea Institute of Materials Science797 Changwondae-roSeongsan.guChangwon 51508Republic of Korea Research Institute of Advanced Materials and Department of Materials Science and Engineering Seoul National University Seoul 08826Republic of Korea Composites Research Division Korea Institute of Materials Science797 Changwondae-roSeongsan-guChangwon 51508Republic of Korea Dept.of Energy and Mech.Eng Gyeongsang National UniversityCheondaegukchi-Gil 38Tongyeong 53064Republic of Korea

Boron nitride nanotubes(BNNTs)show exceptional physical properties including high mechanical strength and thermal conductivity;however,their applications have been restricted due to limited dispersibility in processing ***,a novel BNNT dispersion method with exceptional dispersibility in a wide range of solvents has been demonstrated by surtace polarity modulation through short-molecule pyridine *** atoms in pyridine are selectively bonded to electron-deficient boron atoms of the BNNT surface through Lewis acid-base reaction,which changes the surface polarity of BNNTs from neutral to ***-dispersing pyridine-attached BNNTs(Py-BNNTs)create a thick and stable electronic double layer(EDL),resulting in uniform dispersion of BNNTs in solvents with an exceptional solubility parameter range of 18.5-48 MPa^1/*** uniform dispersion of BNNTs is maintained even after the mixing with diverse ***,composites incorporating uniformly-distributed BNNTs have been realized,and extraordinary property enhancements have been *** thermal conductivity of 20 wt.%Py-BNNT/epoxy composite has been significantly improved by 69.6%and the tensile strength of 2 wt.%Py-BNNT/PVA has been dramatically improved by 75.3%.Our work demonstrates a simple and facile route to dispersing BNNTs in diverse solvents,consequently leading to selective utlization of BNNT dispersed solvents in various application fields.

关键词： boron nitride nanotube one-dimensional nanomaterials surface polarity modulation electrostabilization boron nitride nanotube composite

Function-regeneration of non-porous hydrolyzed-MOF-derived materials

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Nano Research 2019年第8期12卷 1921-1930页

作者： Yo Chan Jeong Jin Weon Seo Jae Ho Kim Seunghoon Nam Min Chang Shin Young Shik Cho Jin Syul Byeon chong rae park Seung Jae Yang Carbon Nanomaterials Design Laboratory Research Institute of Advanced Materials and Department of Materials Science and Engineering Seoul National UniversitySeoul 08826Republic of Korea Advanced Nanohybrids Lab. Department of Chemical Engineering Inha UniversityIncheon 22212Republic of Korea School of Advanced Materials Engineering College of Engineering Andong National University Andong Gyeongsangbuk-do 36729Republic of Korea

A facile synthetic strategy based on a water-based process is developed for the preparation of metal-organic framework (MOF)-derived materials by revisiting the hydrolyzed non-porous metal-organic frameworks (h-MOF). The poor water stability of MOF has been recognized as key limitations for its commercialization and large-scale applications because the hydrolysis resulted in the complete loss of their functionalities. However, we found that the negative effect of hydrolysis on MOF can be nullified during the heat treatment. As similar to the intact MOF, h-MOF can be used as a precursor for the preparation of MOF-derived materials from porous MOF-derived carbons (MDCs) to MDC@ZnO composites. The property of h-MOF-derived materials is almost equivalent to that of MOF-derived materials. In addition, h-MOF turned the weakness of water instability to the strength of facile water-based process for hybridization. With the demonstration of the hybrid composite between h-MDC@ZnO and reduced graphene oxide (rGO) as a prototype example, it exhibited superior electrochemical performance when evaluated as an electrode material for lithium-ion batteries.

关键词： nanomaterials metal-organic framework (MOF) porous materials MOF-derived carbon hydrolyzed MOF

Effective I/O Scheme Based on RTP for Multimedia Communication Systems

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Journal of Computer Science & Technology 2006年第6期21卷 989-996页

作者： Nam-Sup park chong-Sun Hwang Department of Computer Science and Engineering Korea Univcrsity Seoul Korea

The prime standard for audio/video transport in IP networks is the Real-time Transport Protocol （RTP） and it is targeted at useful services for the transport of real-time multimedia data. RTP was originally designed for use in multicast conferences, using the lightweight sessions model. RTP （in particular, the data part） is so tightly coupled to the application that a number of people have developed libraries that implement RTP. However, little is known about the RTP overheads between user area and kernel area within operating systenl. Actually, unnecessary copying between user area and kernel area lowers the system efficiency. In this paper, we present the design and implementation of Enhanced Multimedia Input/Output Scheme based on LINUX. We brought focus to the crossover architecture supporting RTP. Our contributions are able to be summarized into two components： 1） Enhanced Input/Output （EIO） scheme based on LINUX improves the transmission speed by reducing the overheads generated from data copy and context switch between user area and kernel area. And this enables server-based system to transport multimedia data more efficiently. 2） Furthermore, Enhanced Input/Output scheme with RTP （EIORTP） scheme supports efficient multimedia data transmission architecture. The two schemes improve the performance of massive multimedia data transmission.

关键词： kernel area system call EIO RTP EIORTP

Properties of ZnO Thin Films Grown on Si (100) Substrates by Pulsed Laser Deposition

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Journal of Materials Science & Technology 2010年第11期26卷 973-976页

作者： Young rae Jang Keon-Ho Yoo Seung Min park Department of Physics Kyung Hee University Department of Chemistry Kyung Hee University

ZnO thin films were grown on Si （100） substrates by pulsed laser deposition using a ZnO *** substrate temperature was varied in the range of room temperature to 800 ℃,and the oxygen partial pressure of 0.1333 Pa （1 m Torr） to 1333 Pa （10 Torr）.The properties of the resulting films were investigated by photoluminescence （PL）,grazing incidence X-ray diffraction （GIXRD）,X-ray photoelectron spectroscopy （XPS）,and field emission scanning electron microscopy （FESEM）.Based on the ultraviolet （UV,～380 nm） to visible emission ratio in the PL spectrum,the optimum growth conditions were determined to be 600 ℃ and 133.3 Pa （1 Torr）,*** oxygen 1s peak in the XPS spectrum was decomposed into two *** peak at lower binding energy increased in intensity with the oxygen partial pressure from 0.1333 Pa （1 m Torr） to 133.3 Pa （1 Torr） while the other peak *** GIXRD curve at the optimum condition showed strong two peaks （002） and （103）.A strong correlation between the （103） peak intensity and the UV emission intensity was found.

关键词： ZnO Pulsed laser deposition Photoluminescence

An Efficient Data Dissemination Scheme for Spatial Query Processing

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Journal of Computer Science & Technology 2007年第1期22卷 131-134页

作者： Kwangjin park Hyunseung Choo chong-Sun Hwang School of Information and Communication Engineering Sungkyunkwan University 440-746 Suwon Korea Department of Computer Science and Engineering Korea University 5-1 Anam-Dong Seongbuk-Ku Seoul 136-701 Korea

Due to the personal portable devices and advances in wireless communication technologies, Location Dependent Information Services （LDISs） have received a lot of attention from both the industrial and academic communities. In LDISs, it is important to reduce the query response time, since a late query response may contain out-of-date information. In this paper, we study the issue of LDISs using a Voronoi Diagram. We introduce a new NN search method, called the Exponential Sequence Scheme （ESS）, to support NN query processing in periodic broadcast environment. This paper aims to provide research directions towards minimizing both the access latency and energy consumption for the NN-query processing.

关键词： air index wireless data broadcasting mobile computing

Broadcast-Based Spatial Queries

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Journal of Computer Science & Technology 2005年第6期20卷 811-821页

作者： Kwang-Jin park Moon-Bae Song chong-Sun Hwang Department of Computer Science and Engineering Korea University 5-1 Anam-Dong Seongbuk-Ku Seoul 136-701 Korea

Indexing techniques have been developed for wireless data broadcast environments, in order to conserve the scarce power resources of the mobile clients. However, the use of interleaved index segments in a broadcast cycle increases the average access latency for the clients. In this paper, the broadcast-based spatial query processing methods （BBS） are presented for the location-based services. In the BBS, broadcasted data objects are sorted sequentially based on their locations, and the server broadcasts the location dependent data along with an index segment. Then, a sequential prefetehing and caching scheme is designed to reduce the query response time. The performance of this scheme is investigated in relation to various environmental variables, such as the distributions of the data objects, the average speed of the clients and the size of the service area.

关键词： broadcasting location-aware caching prefetching mobile computing

Non-isotropic weighted L^p estimates for the -equation on piecewise smooth strictly pseudoconvex domains

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Science China Mathematics 2008年第12期51卷 2161-2171页

作者： Heungju AHN Hong rae CHO Jong-Do park Nims 3F TowerKoreana 628 Daeduk-Boulevard Yuseong-gu Department of Mathematics Pusan National University Department of Mathematics Seoul National University Department of Mathematics Pohang University of Science and Technology

In this paper we obtain non-isotropic weighted Lp estimates with the boundary distance weight function for the-equation on piecewise smooth strictly pseudoconvex domains under a hypoth- esis of complex transversalit... 详细信息

关键词： non-isotropic norm Cauchy-Riemann equation piecewise strictly pseudoconvex domain

Recent application of biochar on the catalytic biorefinery and environmental processes

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Chinese Chemical Letters 2019年第12期30卷 2147-2150页

作者： Hyung Won Lee Heejin Lee Young-Min Kim rae-su park Young-Kwon park School of Environmental Engineering University of SeoulSeoul 02504Republic of Korea Department of Environmental Engineering Daegu UniversityGyeongsan 38452Republic of Korea Department of Bioenvironmental&Chemical Engineering Chosun College of Science&TechnologyGwangju 61453Republic of Korea

Lignocellulosic biomass is an abundant and environment-friendly source for renewable energy *** value and application of biochar,which is obtained from the thermochemical conversion of biomass,is increasing rapidly because of its high carbon content and *** property of biochar,such as surface area,porosity,and number of functional groups,can be improved by controlling the conditions of biomass conversion,biochar activation,and functionalization *** production and activation of biochar as well as its potential use for soil remediation,pollutant adsorption,and biorefinery have been reviewed extensively over recent *** paper provides a conceptual approach for biochar production and activation together with its application as a catalyst for biorefineries and the removal of environmental contaminants.

关键词： Biomass Thermochemical conversion Biochar Activation Catalyst

Perspective on the critical role of interface for advanced batteries

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Journal of Energy Chemistry 2020年第8期29卷 217-220,I0008页

作者： chong Yan Hong Yuan Ho Seok park Jia-Qi Huang School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Advanced Research Institute of Multidisciplinary Science Beijing Institute of TechnologyBeijing 100081China School of Chemical Engineering Sungkyunkwan University(SKKU)Jangan-guSuwon 440-746Republic of Korea

As an efficient and environmental friendly energy storage system, lithium battery has been integrated into daily mobile life [1].Lithium batteries are becoming indispensable to all types of electronic products such as laptop computers, mobile phones, digital cameras [2]. A typical lithium battery consists of positive electrode(cathode), negative electrode(anode), electrolyte and other inactive materials(binder, conductive agent, separator) [3].

关键词： Interface Lithium metal Graphite Solid electrolyte interphase(SEI) Solvation Specific absorption