• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2000.11a
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• pp.6-6
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• 2000

국가우주개발 중장기 계획에 의거, 독자 인공위성 발사체 개발에 필요한 필수기술을 확보하기 위하여 액체추진제 로켓엔진의 개발에 대한 필요성이 대두되었으며, 이에 따라 한국항공우주연구소는 과학로켓 3호(KSR-III)에 적용하기 위한 액체추진기관을 개발하고 있다. 이러한 목적으로 kerosine/LOx를 사용하며 13톤급의 추력을 낼 수 있는 시제엔진이 설계, 제작되었으며 이 엔진에 대한 연소시험이 실시되었다. 본 연구에서는 액체추진기관 시험을 위한 일련의 진행사항, 시험방법을 소개하며, 시험을 통하여 획득한 정특성 자료 및 동특성 자료에 대하여 분석하였다.(중략)

• Journal of Adhesion and Interface
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• v.13 no.3
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• pp.101-108
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• 2012

Narrowly dispersed poly(BMA-co-MMA) and PBMA latices (PSD : 1.002~1.008) were synthesized successfully by surfactant-free emulsion polymerization with 2,2' azobis(2-methyl-propionamidine) dihydrochloride (AIBA) and $K_2S_2O_8$ (KPS). The number average particle diameter and the number average molecule weight were found to be 160~494 nm and (1.25~7.55) ${\times}10^4$, respectively. The influences of BMA/MMA ratio, monomer and initiator concentrations, addition of DVB/EGDMA crosslink agent, and polymerization temperature on the polymerization rates and on the particle size and molecular weight were studied. The rate of polymerization increased with increasing MMA concentration in BMA/MMA weight ratio. The particle diameter as well as the polymer molecular weight could be controlled easily by controlling the BMA/MMA weight ratio, monomer concentration, AIBA and KPS concentration, and polymerization temperature.

• Journal of dental hygiene science
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• v.8 no.3
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• pp.109-115
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• 2008

Two t-amines, N,N-dimethylaniline (MA), N,N-dimethyl-p-toluidine (MPT), were investigated as new visible light amine initiators for a dental resin composite of UDMA in order to improve photopolymerization effect. Three t-amines mixed with three photosensitizers, camphorquinone(CQ), 1-phenyl-1,2-propane dione(PD) and diacetyl (DA), respectively. And then this mixtures are added to resin monomer, UDMA. Photopolymerization efficiency of UDMA was studied through the use of FT-IR absorption spectroscopy. The photopolymerization effect of amine initiators were compared with that of 4-(dimethylamino)ethyl methacrylate (AEM), the most widely used photoinitiator. The photopolymerization efficiency of UDMA containing the amine initiator increased with irradiation time. The relative polymerization efficiency containing the CQ photosensitizer increase was in the order: AEM < MPT < MA. And the relative polymerization efficiency containing the PD photosensitizer increase was in the order: MPT < AEM < MA. This result shows that MA is most efficient amine initiator with CQ and PD.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.7
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• pp.701-708
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• 2009

The flight control law of developed flight control computer(DFLCC) is developed based on operation flight program of advanced trainer aircraft full scale development final configuration. The flight control law design is used common use development tool in GUI(Graphic User Interface) environment. The flight control law transformed to C-Code is reflected in OFP. The OFP is verified by the standardized verification process. But, before standardized verification process, we need preliminary verification process such as similarity of flight control law and reliability of developed HILS. Similarity of flight control law is verified by comparing the aircraft response of advanced trainer aircraft and those of the developed control law. Also, reliability of developed HILS is verified by comparing the aircraft response of HILS and Non-real time simulation result. This paper verifies similarity of developed control law and reliability of HILS environment as comparing aircraft response.

• Journal of the Korean association of regional geographers
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• v.16 no.5
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• pp.497-516
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• 2010

The purpose of this study is to critically investigate the places of the 'Daegusibyeong(大丘十詠)', written by Seo, Geojeong based on Chinese poem, old documents, and field surveys in terms of a geographical perspective. It is asserted that the controversial aspects on the 'Daegusibyeong(大丘十詠)' are corrected through the analysis of old documents and field surveys. The results are summarized in the followings. 1) Ascertain historical and geographical evidence on places of 'Daegusibyeong(大丘十詠)' are accomplished properly based on old documents and field surveys. 2) The existing misinterpretation of the 'Daegusibyeong(大丘十詠)' are corrected by the finding of one Chinese character in the 'Dongsasimseung(桐寺尋僧)', the seventh poem of 'Daegusibyeong(大丘十詠)' consisted of 10 Chinese poems. 3) Subjects and content of the 'Daegusibyeong(大丘十詠)' in Sagajib(四佳集) are more rightly written than those of the old documents such as Daegueubji(大丘邑誌), Sinjeungdonggukyeojiseungram(新增東國輿地勝覽). 4) A few mistakes in the subject and word of the 'Daegusibyeong (大丘十詠)' are corrected as compared with the those of the old documents. 5) It is assumed that the brand value and image of Daegu city will be improved if the 'Daegusibyeong(大丘十詠)' is restored based on the results of the study and its restoration is utilized in Daegu city tour program.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.5
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• pp.675-681
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• 2011

In this paper, we dealt with the design and fabrication of a medium pressure ultra-violet (UV) lamp and a magnetic ballast which are main components for ballast water treatment systems (BWTS). To acquire an optimal discharge condition of UV lamp, electrical and optical characteristics depending on the argon gas volume and the amount of mercury were experimentally analyzed. Rated voltage, current and power consumption of a prototype lamp were 490 [V], 8.6 [A] and 4.0 [kW], respectively. UV intensity of the lamp was 15 [%] higher than that of an equivalent lamp which is used in a BWTS. The magnetic ballast was designed in a UI core type through theoretical analysis and simulation. The open voltage and the rated power consumption of the ballast were 920 [V] and 8.5 [kVA] respectively. The disinfection efficacy which is carried out in a BWTS equipped with the UV lamp and magnetic ballast was over 99.99 [%], and this satisfy the IMO regulations.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.807-812
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• 2011

Fuel-side cold-flow tests were performed on the technology demonstration model of a 75 ton-class liquid rocket engine combustion chamber for the first stage of the Korea space launch vehicle II. Pressure drop in the cooling channels of the combustion chamber was measured by changing fuel mass flow rate through a pressure regulating system. Pressure drop in each segment of the chamber could be obtained and a lot of pressure drop was caused by high flow velocity in the nozzle throat segment. The accuracy of a hydraulic analysis method for calculating a pressure loss in cooling channels could be verified by applying it to the cold-flow test conditions.

• Journal of the Korean Ceramic Society
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• v.41 no.4
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• pp.313-322
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• 2004

Thick film photolithography is a new technology in that the lithography process such as exposure and development is applied to the conventional thick film process including screen-printing. In this research, low-temperature cofireable silver paste, which enabled the formation of thick film fine-line using photolithographic technology, was developed. The optimum composition for fine-line forming was studied by adjusting the amounts of silver powder, polymer and monomer, and the additional amount of photoinitiator, and then the effect of processing parameter such as exposing dose on the formation of fine-line was also tested. As the result, it was found that the ratio of polymer to monomer, silver powder loading, and the amount of photoinitiator were the main factors affecting the resolution of fine-line. The developed photosensitive silver paste was printed on low-temperature cofireable green sheet, then dried, exposed, developed in aqueous process, laminated, and fired. Results showed that the thick film fine-line under 20$\mu\textrm{m}$ width could be obtained after cofiring.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.12
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• pp.994-1001
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• 2013

Process of helicopter development is divided in design, manufacture and test & evaluation phase. Test & evaluation is performed step by step in order of component test, rig test, system ground test and flight test. After completing ground test and before first flight, US military specification requires 50hrs-PFAT in order to assure flight safety. PFAT is the test which requires tie-down and severe load imposition and it needs special ground test vehicle which is similar to helicopter prototype as well as much cost and period. In case of KUH, we have performed tailored PFAT considering KUH development environment. In this paper, we propose a proper way to perform the PFAT in accordance with development environment by giving KHU PFAT procedure and result.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.6
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• pp.56-61
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• 2012

Fuel-side cold-flow tests were performed on the technology demonstration model of a 75 ton-class liquid rocket engine combustion chamber for the first stage of the Korea space launch vehicle II. Pressure drop in the cooling channels of the combustion chamber was measured by changing fuel mass flow rate through a pressure regulating system. Pressure drop in each segment of the chamber could be obtained and a lot of pressure drop was caused by high flow velocity in the nozzle throat segment. The accuracy of a hydraulic analysis method for calculating a pressure loss in cooling channels could be verified by applying it to the cold-flow test conditions.