• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.93-93
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• 2011

고진공 펌프 국산화의 일환으로 터보분자 펌프와 크라이오 펌프 개발이 진행 중이다. 크라이오 펌프 개발은 기계연구원, 우성진공(주), 국민대학교가 연합해서 수행하고 있다. 올해 9월말에 끝나는 1단계 마지막 3차 년도에는 두 고진공 펌프 모두 시제품을 완성하고 성능을 입증해야 한다. 이를 위해 고진공 펌프 개발과 별도로 진공 펌프 종합특성평가 시스템 개발도 표준과학연구원 주도로 진행되고 있는데 크라이오 펌프 평가 시스템은 원자력연구원이 담당하고 있다. 완성된 크라이오 펌프 성능평가 장치는 상온 기준 5${\times}$10-11 mbar의 기저압력을 보이고 있어서 초고진공 영역에서 크라이오 펌프 운전성능을 평가할 수 있는 준비를 마쳤다. 현재 크라이오 펌프 냉동기는 전반적으로 목표 설계치에 근접한 냉각성능을 나타내고 있는데 예를 들면 2차 냉각단 냉각능력이 10 K, 10 W로 대형 크라이오 펌프를 제작하기에도 충분하다. 활성탄 어레이도 여러 모델들을 자작하여 배기성능을 시험해 보았으므로, 최종적으로 3,600 L/s 급에 적합한 어레이를 만들고 이를 개발된 냉동기에 얹고 열차폐와 몸통을 씌워 펌프로서의 운전성능을 평가하는 일이 남아있다. 시제품은 상용품과 달리 기기가 차지하는 공간이 크고 부대설비가 복잡해서 운전성능 평가 장치에 부착해서 실험하기 어려울 수도 있으므로 기계연구원 현장에서 진공 게이지와 기체도입구만 부착한 마구리 플랜지를 펌프 흡기구 위에 달고 간이로 배기속도를 측정하는 것도 고려하고 있다. 이 경우는 표준용기를 사용할 때보다 배기속도가 과대평가되므로 이를 보정해 주는 방안을 마련해 놓아야 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.1006-1015
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• 1998

In general, attenuation at frequencies over 20GHz is mainly due to absorption by satmospheric gases, rain, and snow. Among this factors rain become an important limiting factor. Rain attenuation is highly influenced by rainfall-intensity and it varies over time and space. Thus it is requeired to obtain spatial and temporal data of rainfall-intensity for precise prediction of rainfall attenuation. In this paper, rainfall intensity of thiry-two measurement sites in South Korea excluding JeiJdo Islands over recent ten years is obtained and the regional relation between rainfall-intensity and percent of time is analyzed. Also we present the new method about rainfall-intensity cumulative distribution.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.463-466
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• 2008

The weapon systems with a liquid propulsion engine have been used for various purposes and demands of the liquid fuel with variety of properties for its operational purposes and environment. The cyclic hydrocarbons including norbornane or dicyclopentane structures have many applications to the guided weapon systems due to the high density and high energy characteristics, also efforts have been given in many fields. In this study, the cyclic hydrocarbons that we designed and fabricated were investigated to obtain tendency on the structures.

• Korean Journal of Metals and Materials
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• v.49 no.9
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• pp.739-745
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• 2011

Beta-type alloys are the most versatile class of titanium alloys. They offer the highest strength to weight ratios and very attractive combinations of strength, toughness, and fatigue resistance inlarge cross sections [1]. The present study was made to obtain useful information for the design of ${\beta}$-type titanium alloys with high-strength properties by using the $DV-X{\alpha}$ method. Employing two calculated parameters, the bond order (Bo) and the d-orbital energy level (Md) of alloying elements in ${\beta}$-type titanium alloy was introduced and used for prediction of mechanical properties. Thus, high-strength titanium alloys were designed by calculating the Md and Bo values of the previous and present titanium alloys.

• Prospectives of Industrial Chemistry
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• v.14 no.4
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• pp.29-40
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• 2011

앞으로 글로벌 시장에 진입할 수 있는 작물보호 신물질 개발을 위해서는 기술 난이도가 크면서 파급성 및 경제성을 갖는 친환경 신규작용점 탐색과 독창적 Scaffold를 갖는 후보물질 또는 천연물소재 발굴에 주력해야 하며, 이를 지원하는 HTS, 화합물은행 및 천연물은행 활용 분자설계 및 최적화 합성기술 등 후보물질 발굴 핵심 기술개발에 국가적인 지원이 지속적이고 장기간에 걸쳐 이루어져야 한다. 고품질의 식량생산 관리기술은 물론 석유대체 에너지 확보를 위한 농작물 바이오매스(작물, 사료, 바이오연료 등) 생산관리기술로서, 그린바이오기반(Target 효소, 천연물소 재탐색응용) 저탄소 녹색성장을 실현시키기 위한 친환경적인 생화학 작물보호제 개발이 필요하다. 또한 인구 증가와 유가상승 등 전 세계적인 경제위기 극복과 이산화탄소 증가에 따른 온난화 등 지구환경보존의 중요성이 크게 증가되면서 안전한 먹거리 생산과 환경오염을 최소화하는 지속적 생산체제를 갖추기 위하여 LOHAS (Lifestyle Of Health And Sustainability) 트랜드가 최근 농업의 화두로 떠오르고 있다. 이를 만족시키기 위하여 OECD를 중심으로 하는 선진 국가들은 기존 작물보호제의 사용을 5년 이내에 현재 사용량의 절반 이하로 감소시키고자 하고 있는데, 특히 지속적 재배와 국민건강 보호를 위한 LOHAS 농작물의 생산이 매년 50-100억불로 성장하고 있다. 이러한 추세는 2017년까지 그 성장세가 계속 지속될 것으로 예상되고 있어 미생물/생화학 중심의 바이오작물보호제의 개발은 LOHAS 트랜드를 충족시킬 수 있는 유력한 수단으로 인식되고 있다.

• Journal of the Korea Society of Computer and Information
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• v.28 no.10
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• pp.113-121
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• 2023

Network pharmacology in traditional Korean and Chinese medicine studies the molecular and biological aspects of herbal medicine using computational methods. Despite variations in databases, techniques, and criteria, most studies follow similar steps: constructing herb-compound networks, compound-target networks, and target interpretation. To ensure efficient and consistent analysis in herbal medicine network pharmacology, we designed and implemented a common analysis pipeline. We showed its reliability with existing databases. The proposed system has a potential to facilitate network pharmacology analysis in traditional medicine, ensuring consistent analysis of various herbal medicines.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.11
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• pp.767-773
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• 2017

Printed Circuit Heat Exchanger (PCHE) has an advantage for exchanging thermal energy between high-pressure and high-temperature fluids because its core is made by diffusion bonding method of accumulated metal thin-plates which are engraved of flow channel. Moreover, because it is possible that the flow channel can be micro-size hydraulic diameter, the heat transfer area per unit volume can be made larger than traditional heat exchanger. Therefore, PCHE can have higher efficiency of heat transfer. The smaller channel size can make the larger heat transfer area per unit volume. But if high pressure fluid flows inside the channel, the channel wall can be deformed, the structure and shape of flow channel and header have to be designed appropriately. In this study, the design methodology of PCHE channel in high pressure environment based on pressure vessel codes was investigated. And this methodology was validated by computational analysis.

• KSBB Journal
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• v.18 no.3
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• pp.190-196
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• 2003

An analytical system detecting DNA particularly utilizing a concept of membrane strip chromatography initially applied to home-version tests for, such as, pregnancy and ovulation has been developed. We have chosen S. typhimurium as model analyte among food-contaminating microorganisms that occurred in high frequencies, and invA gene, as a detection target, specific to Salmonella species. This gene was able to be amplified by PCR under optimal conditions employing newly designed primers in our laboratory. The PCR product was specifically measured via hybridization between the analyte and a DNA probe, which was a totally different feature from the conventional gel electrophoresis detecting the products based only on the molecular size. It is notable thar the DNA probe sequence was specially designed such that no separation of excess primers present after PCR was required. This was immobilized on a nitrocellulose (NC) membrane via streptavidin-biotin linkage minimizing a steric effect when the hybridization with the amplified DNA took place. The analyrical system detected the microorganism in a concentration of minimum $10^3$ cfu/mL (i.e., 10 cells per system), estimated from the standard curve, 20 to 40 minutes after adding the sample. This sneitivity was approximately 10 times higher than that of gel electrophoresis as an analytical tool conventionally used. Furthermore, the assay was able to be run at room temperature, which would ofter an extra advantage to users.

• Journal of Korea Foresty Energy
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• v.17 no.1
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• pp.47-55
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• 1998

In the search for broadband damping composites, it is desirable to have polymers with a broad and high loss region, covering the entire temperature and frequency range of interest. Interpenetrating polymer networks, IPN's, are materials composed of two or more crosslinked polymers intimately and irrevocably interwinded. The resulting distribution of microenviron-ments can result in a materials with a high mechanical loss broad end over that of either polymer component alone. In this study, several series of copolymer, crosslinked copolymer and copolymer/copolymer IPN's were synthesized for possible use as broadband damping materials. Then their dynamic tensile properties were measured and compared with the damping properties of sandwich composites. Dynamic mechanical analysis showed that the temperature of loss peak may be varied over a wide temperature range with formulation. The compatibility of IPN`s was depended on the compatibility of A and B polymers as well as crosslink density. The damping factor(tan ${\delta}_c$) of composites became greater when a polymer of approximate storage module(E`) range of 5X10$^7$ to 10$^9$ dyne/cm$^2$ and large tan ${\delta}$ at the same time was used. The damping properities of poly (2-EHA80-co-St20)/poly(2-EHA20-co-St80) IPN`s crosslinked with 3%-DEGDM were relatively better over a broad temperature range.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.69-74
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• 2018

With the increasing development of industrial society and the availability of high quality electrical energy, the simplification of operation and maintenance procedures is required, in order to ensure the reliability and safety of electrical systems. In this paper, the dielectric breakdown characteristics of $N_2-O_2$ mixed gas solid insulation, which is used as an alternative to SF6 in various electric power facilities, are verified. When the gas mixture has a composition ratio similar to that of the atmosphere, the dielectric breakdown characteristics are relatively stabilized. It was confirmed that the breakdown voltage of the gas in the electrode near an equal electric field increased with increasing pressure according to Paschen's rule. The breakdown voltage of the surface increased linearly with increasing pressure, and the difference was caused by the mixing ratio of $O_2$ gas. This change in the surface insulation breakdown voltage was caused by the influence of the electrically negative $O_2$ gas and the intermolecular collision distance. In this study, the influence of the intermolecular impact distance was larger (than that in the absence of the electrically negative $O_2$ gas). The breakdown voltage relation applicable to Teflon according to the surface insulation characteristics was calculated. The characteristics of the surface insulation properties of Teflon, which is used as a solid insulation material, were derived as a function of pressure. It is thought that these results can be used as the basic data for the insulation design of electric power facilities.