수정진동자를 이용한 계면활성제의 특성 분석

송성훈,박진영,이행자,조홍식,장상목 동아대학교 환경문제연구소 1999 硏究報告 Vol.22 No.2

The phase transition phenomena and the phase separation phenomena of surfactants(SPES) are analyzed using QCA with resonant frequency and resonant resistance. The phase transition phenomena of SPES at 30℃ can be determined by measuring the resonant frequency and resonant resistance by lecithin coated on quartz crystal. The surfactants capacity of SPES can be analyzed by measuring the resonant frequency and resonant resistance of surfactants using QCA.

건물 산란계수를 이용한 비가시거리영역에서의 전파환경

강부식,김홍수,홍성욱 濟州大學校工科大學産業技術硏究所 1997 尖端技術硏究所論文集 Vol.8 No.1

In this paper, the scattered electric fields is computed to predict the shielding zone by analysing the effect of the reflected azimuth anlge at the building, and considering the path differences at observation point between the rays from origin and any point in the building. The scattering coefficients, which are applicable to the prediction of shielding zone, are computed and compared with measured one. We found that the scattering power become weak over 10 degree of the azimuth angle at which the scattering coefficient is lower than 40 dB. From this. the shielding zone can be estimated.

건물 산란계수를 이용한 비가시거리 영역에서의 전파환경

홍성욱,강부식,김흥수 濟州大學校 産業技術硏究所 1997 산업기술연구소논문집 Vol.8 No.1

In this paper, the scattered electric fields is computed to predict the shielding zone by analysing the effect of the reflected azimuth anlge at the building, and considering the path differences at observation point between the rays from origin and any point in the building. The scattering coefficients. which are applicable to the prediction of shielding zone. are computed and compared with measured one. We found that the scattering power become weak over 10 degree of the azimuth angle at which the scattering coefficient is lower than 40 dB. From this, the shielding zone can be estimated.

Water-in-Carbon Dioxide 마이크로에멀젼에서 나노 크기의 이산화티탄 합성 및 p-니트로페놀의 광분해에 대한 연구

이만식,이근대,홍성수 한국화학공학회 2002 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.40 No.4

CO_2에 용해 능력이 우수한 PFPE-NH_4(ammonium carboxylate perfluoro polyether) 및 PDMAEMA(poly(2-(dimethylamino)-ethyl methacrylate))-b-PFOMA(polu(1H, 1H, 2H, 2H-perfluoroocthyl methacrylate)) 계면활성제를 사용하여 W/C 마이크로에멀젼에 의해 나노 크기의 TiO_2를 제조하였다. TGA-DTA, FT-IR, XRD, TEM 등을 이용하여 나노 입자 제조시 W_0(H_2O/surfactant molar ratio)비에 따른 입자의 크기 및 결정성 등 물리적 성질을 조사하였다. 또한 제조된 TiO_2 나노 입자의 광촉매적 특성을 알아보기 위해 회분식 반응장치를 이용하여 p-니트로페놀의 광활성을 조사하였다. 제조된 TiO_2 나노 입자는 소성온도 250-450℃ 범위에서 유기물질과 수산화물이 분해 되어 450℃ 이상 비결정 구조에서 anatase 구조로 상 전이 되었다. W/C 마이크로에멀젼에서 제조된 나노 입자의 결정성 및 결정크기는 W_0 비가 증가할수록 증가하였다. p-니트로페놀의 광분해반응에서 반응성은 결정크기에 영향을 받았으며, 결정의 크기가 작을수록 반응성이 증가하였다. Titania nanoparticles were prepared by controlled hydrolysis of titanium tetraisopropoxide(TTIP) in PFPE-NH_4(ammonium carboxylate perfluoropolyether) and PDMAEMA(poly(2-(dimethylamino)ethyl methacrylate))-b-PFOMA(poly(1H, 1H, 2H, 2H-perfluoroocthyl methacrylate))/Water-in-CarbonDioxide Microemulsions. The physical properties, such as crystallite size and crystallinity according to W_0 ratio have been investigated by TGA-DTA, FT-IR, XRD and TEM. In addition, the photocatalytic degradation of p-nitrophenol has been studied by using batch reactor in the presence of UV light in order to compare the photocatalytic activity of prepared nanosized titania. The residual organic compound and hydroxyl group were completely removed in calcination temperature from the 250-450℃ and the amorphous phase changed into anatase structure above 450℃. The crystallinity and crystallite size of nanoparticles produced in water-in-carbon dioxide microemulsions increased with an increase of the W_o ratio. In the photocatalytic degradation of p-nitrophenol, the photocatalytic activity is mainly determined by the crystallite size of titania and the reaction rate increased with an decrease of crystallite size.

W/O 마이크로에멀젼에 의한 나노크기의 TiO₂/SiO₂ 합성에서 물/계면활성제의 몰 비(W_(0)) 영향 및 그 광분해 특성

이만식,주창식,이근대,홍성수 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.4

나노크기의 TiO₂/SiO₂입자는 음이온 계면활성제 AOT(sodium bis(2-ethylhexyl) sulfosuccinate)를 사용하여 W/O 마이크로 에멀젼에서 TTIP(titanium isopropoxide)와 TEOS(tetraethylorthosilicate)의 가수분해 반응에 의해 제조하였다. 그때 TEOS의 몰분율은 0.1이였다. 나노입자 제조시 W_(0)(H₂O/AOT)비에 따른 열적안정성, 표면적, 결정성 및 결정크기 등과 같은 물리적 특성은 TEM, XRD, BET, FT-IR, TGA-DTA 등을 사용하여 분석하였다. 또한 광촉매적 특성을 알아보기 위해 회분식 반응장치를 이용하여 p-니트로페놀의 광분해 활성을 조사하였다. 제조된 Ti0₂/SiO₂ 나노입자는 열처리 온도 105℃, 300℃에서 비결정구조를 가졌으며, 소성온도 800℃에서는 Ti0₂ 결정입자 내에 무정형의 SiO₂로 인해 열적 안정성이 증가되었고, 여전히 anatase 결정을 유지하였다. 그리고 Ti0₂/SiO₂(90/10) 입자에서 SiO₂ 결정은 관찰되지 않았다. 제조된 촉매는 대체로 구형이며 아주 균일한 분포를 갖는 것으로 관찰되었다. W_(0) 비가 증가할수록 결정크기는 증가되었고, 표면적은 감소하는 경향을 나타내었다. 또한 p-니트로페놀에 대한 광분해 활성은 순수한 Ti0₂ 보다 Ti0₂/SiO₂(90/10) 촉매가 우수하였다. Nanosized TiO₂/SiO₂ particles were prepared by hydrolysis of TTIP (titanium isopropoxide) and TEOT (tetra-ethylorthosilicate) in sodium bis (₂-ethylhexyl)sulfosuccinate (AOT) reverse micelles. The mole fraction of TEOS was 0.1. The physical properties, such as surface area. thermal stability, crystallite size and crystallinity according to W_(0), ratio have been investigated by TEM, XRD, BET, FT-IR, TGA and DTA. In addition. the photocatalytic degradation of p-nitrophenol has been studied by using batch reactor in order to compare the photocatalytic activity of prepared nanosized TiO₂/SiO₂, particles. It is shown that the XRD pattern of the particle heat treated at 105℃ and 300℃ indicates amorphous and the major phase of all the prepared particles were anatase structure. No significant rutile phase was observed although the calcination temperature at 800℃ and no peaks SiO₂ crystal were also observed for TiO₂/SiO₂ (90/10). The presence of amorphous SiO₂ in TiO₂/SiO₂ particle enhanced the thermal stability of TiOz particle resulting in the suppression of the phase transformation from anatase to rutile phase. The crystallite size of prepared particles decreased with decreasing W_(0) ratio. The surface area increased with decreasing W_(0) ratio. In addition, TiO₂/SiO₂ (90/10) particles shows higher photoactivity than that of pure TiO₂ particles.

클러스터하에서 효율적인 네트워크 메모리 구현

金善一,姜盛植,閔景玟 弘益大學校 科學技術硏究所 2001 科學技術硏究論文集 Vol.12 No.-

In a cluster system where nodes are connected via high-speed networks, accessing data in remote memory could take less time than accessing data in a local disk. As the price of DRAM gets cheaper, it becomes more attractive to use idle memory in a remote node to store data for future accesses. Network memory has been studied to use the idle remote memory for paging space or buffer caches, and it has been shown that network memory could improve the overall system perfoiinance by reducing the number of accesses to relatively slow local disks. In previous studies, operating system kernels or user-level libraries were modified to use network memory. However, these approaches requires either the modification of the kernels or user applications. In this paper, we propose using operating system expandibility features, such as loadable modules in LINUX, and a block device driver wrapper which accesses remote memory for data instead of accessing local disks. Our scheme does not need kernel modifications or user application changes. We present the design and implementation of the block device driver wrapper in detail in this paper.

긴 관동맥병변에서 긴 스텐트삽입에 대한 임상경과 및 재협착율

김영학,박성욱,정상식,박훈기,이상곤,이일수,이철환,김재중,홍명기,박승정 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.6

KOSDIC 포맷의 응용수준별 활용모델 개발 : KOSDIC-XML의 개발 제안을 중심으로 Proposing the Development of KOSDIC-XML

김성아,윤기병,이명식,김성식 대한건축학회 2004 대한건축학회논문집 Vol.20 No.4

This study proposes a methodological framework for extending the KOSDIC format, which has been developed as a standard for construction drawing file exchange. The Ministry of Construction and Transportation, in cooperation with the KICT(Korea Institute of Construction Technology), has recently finished the development of the KOSDIC 1.0, and is now seeking for strategic application scenarios in order to disseminate the KOSDIC format throughout the field works as well as the government institutes. The basic idea is that the KOSDIC format may not be well accepted in favor of legacy CAD systems unless otherwise clear benefits are experienced. Thus, we need first to define the next levels of KOSDIC development based on technical requirement and advances, second, to provide a progressive operation framework which extends the KOSDIC functionalities. Through the investigation of similar research efforts and by applying recent advances in Information Technology area, the authors have formulated futuristic application scenarios of KOSDIC format. Among the suggested methods, this paper presents the proposal of KOSDIC-XML. The KOSDIC-XML is an XML based application framework which extends the KOSDIC format by integrating various web technologies. They include channel based XML technology, Webservice framework, and distributed computing. The result of the research will be used for a theoretical framework KOSDIC-XML schema and its prorotype applications at the next phase of this research.

복어중독에 의한 가사 상태에서 소생한 1예

송승찬,신진호,강석우,박경남,최호순,박근태,문희식,기춘석,이성희,윤병철,노우균,조균석,이민호 大韓應急醫學會 1998 대한응급의학회지 Vol.9 No.3

Tetrodotoxin is a neurotoxin produced by about 90 species of puffer fish and causes paralysis of central nervous system and peripheral nerves by blocking the movement of all monovalent cation. Ingestion of tetrodotoxin produces clinical manifestations such as paresthesias(within 10-45 min), vomiting, lightheadedness, salivation, muscle twitching, dysphagia, difficulty in speaking, convulsion and death that expressed by cardiopulmonary arrest with loss of brain stem reflex sometimes. Tetrodotoxin prevents or delays ischemia induced neuronal death by way of following 3 mechanisms. Firstly, it reduces the energy demand of the brain tissues. Secondly, it delays or even prevents anoxic depolarization. Finally, it deminishes ischemia induced cell swelling and cerebral edema. We report a case of puffer fish poisoning which presented with cardiopulmonary arrest and loss of brain stem reflex, but completely recovered by aggressive cardiopulmonary resuscitation.

Selection and Grading Aspects of Language Materials in the Elementary School English Textbooks

Seong-Sig Kim 한국외국어교육학회 2003 Foreign languages education Vol.10 No.2