• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.399-404
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• 2010

추진제 주입압력 350 psia 에서 0.95 lbf 의 정상상태 공칭추력을 내는 단일액체추진제 하이드라진 추력기의 펄스모드 시험 결과를 추진제 공급압력, 추력기 작동환경 진공도, 그리고 추력펄스 등의 변이와 함께 추력기의 열적 반응거동과 더불어 제시한다. 시험자료는 임펄스 비트, 진공 비추력, Force Centroid 등의 펄스모드 성능특성인자로 변환되어 상세한 분석이 이루어지고, 1 lbf급 표준형 단일추진제 로켓엔진의 펄스모드 기준성능과 성공적으로 비교된다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.355-355
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• 2010

The epitaxial growth of MgO film on Fe(001) has been investigated by scanning tunneling microscopy (STM). After confirming the clean Fe(001)-c($2{\times}2$) substrate by STM, Mg was deposited at room temperature (RT) under $O_2$ partial pressure of $10^{-7}\;Torr$. The MgO was grown as clusters, not as an epilayer even after postannealing at $400^{\circ}C$, as shown in Figure (a). On the contrary, when Mg was deposited on Fe(001)-c($2{\times}2$) at RT and post-oxidized through exposing $O_2$ at partial pressure $10^{-7}\;Torr$, the thin-layered film with some clusters was formed. Extended-annealing at $400^{\circ}C$ reduced the cluster density, and finally the single and epitaxial MgO-c($2{\times}2$) film was formed on Fe(001)-c($2{\times}2$) as shown in Figure (b). This ultrathin MgO film formed on Fe is expected to be applied to many technological applications, such as catalysis, microelectronics, and magnetic devices.

• 한국수산과학회지
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• 제33권5호
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• pp.399-402
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• 2000

일반적인 수산물 통조림의 내용물 속에는 물, 기름 및 조미액즙 등 packing medium이 들어있다. 본 연구에서는 새우, 꽁치 및 굴을 원료로 건조 및 조미 후 packing medium이 없는 새로운 형태의 조미통조림을 제조하고 이들 제품의 진공도별 (15, 30, 45 및 60cmHg) 열침투 특성을 조사할 목적으로 본 연구를 수행하였다. 진공도별 제품의 열침투 속도는 진공도가 높을수록 빠르게 나타났으며 동일시간 살균했을 때 진공도가 높을수록 Fo치가 높게 나타났다. 한편 상법으로 제조된 water pack과 본 시험에서 제조한 조미통조림과의 열침투 속도를 비교했을 때 새우와 꽁치 조미통조림의 경우는 진공도 15cmHg 이상에서는 열침투 속도가 water pack 제품보다는 빠르게 나타났고 굴 제품의 경우는 water pack 제품이 30cmHg 이상에서 열침투 속도가 빠르게 나타났다. 따라서 packing medium이 없는 조미 통조림의 경우 진공도 30cmHg 이상이 되면 기존의 water pack 제품보다 열침투 속도가 빠르다는 사실이 관찰되었다.

• 한국진공학회지
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• 제11권4호
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• pp.235-239
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• 2002

식각된 트랜치의 내부에 다결정 실리콘 측벽을 형성하고, 감압 화학기상 증착법(RPCVD: Reduced Pressure Chemical Vapor Deposition)을 이용해서 이를 선택적으로 성장시킴으로써 트랜치를 채우는 새로운 트랜치 격리방법을 제안하였다. 공정진행 결과, 측벽의 초기깊이와 선택적으로 성장되는 실리콘의 두께가 트랜치의 최종형태를 결정하는 가장 중요한 요소임을 확인할 수 있었다. 이 방법은 CMP 공정을 거치지 않고도 트랜치의 내부만이 실리콘으로 채워진 구조를 구현함으로써, 공정을 단순화할 뿐만 아니라 불균일 연마와 흠집발생 등 기존의 CMP 공정에서 발생할 수 있는 문제들을 방지할 수 있다는 장점을 지니고 있다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.935-938
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• 2007

In suction nozzle of a vacuum cleaner, where flow-induced noise is generated mainly by flow resistance, several ideas to reduce noise are investigated. To increase fan performance, blade number is optimized and a centrifugal fan is replaced by a cross-flow fan, In addition, gear ratio of fan to drum brush is changed. It is found that fan performance is increased by adopting these methods. Next, the blade height of the fan is decreased to reduce sound pressure level, which causes inevitably decrease in fan performance. Eventually, flow-induced noise is reduced by 6.3 dBA in its overall level with the fan performance maintained.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.249-251
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• 2001

A novel technology for recycling valuable metals contained in waste dry-battery by vacuum metallurgy was devised by theoretical analysis. On the condition of the total chamber pressure of 1.013$\upsilon$10$^1$Pa, Hg, Cd and Zn are distilled in the temperature range of 773~973K, Pb is volatilized in the range of 1173~1273K while Mn, Cu, Fe and C are remained in residual. MnO$_2$and ZnO are reduced by carbon in waste dry-battery in 773~1273K. Pure metals including Zn, Cd, Hg and Pb can be recovered respectively from their mixed vapor by fractional condensation. Metal Cu and MnO$_2$can be obtained from the residual by hydrometallguical method. The technology can eliminate the pollution of Cd, Hg and Pb to environment.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.353-353
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• 2010

Alcohol is a vesatile polar solvent for molecules. As a preparation to deposit large molecules, we studied interaction of solvent molecules on metallic surface. in this work, we report on methanol adsorption on NiAl(110) with scanning tunneling microscopy (STM). These alcohol solvent molecules were deposited by a pulse injection method suitable for deposition of thermally unstable molecules. The injection of liquid alcohol onto the substrate in UHV was performed by using a high-speed solenoid valve with the back-pressure reduced down to 100 Torr. This technique allowed precise control over the amount of dosing of molecules to less than 1 L. Alcohol-induced features, attributed to methoxy, were found on bare NiAl(110) surface.

• 한국초전도ㆍ저온공학회논문지
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• 제20권4호
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• pp.11-15
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• 2018

Torque tubes in High Temperature Superconducting (HTS) motor transfer torque from superconducting field winding rotor to the room temperature shaft. It should have minimum heat conduction property for minimizing the load on cryo-refrigerator. Generally, these torque tubes are made with stainless steel material because of high strength, very low outgassing and low thermal contraction properties at cryogenic temperatures and vacuum conditions. With recent developments in composite materials, these torque tubes could be made of composites such as Kevlar and S-Glass, which have the required properties like high strength and low thermal conductivity at cryogenic temperatures, but with a reduced weight. Development and testing of torque tubes made of these composites for HTS motor are taken up at Bharat Heavy Electricals Limited (BHEL), Hyderabad in collaboration with Central Institute of Plastics and Engineering Technology (CIPET), Chennai and Indian Institute of Technology (IIT), Kharagpur. As these materials are subjected to vacuum, it is important to measure their outgassing rates under vacuum conditions before manufacturing prototype torque tubes. The present study focusses on the outgassing characteristics of Kevlar and S-Glass, using an Outgassing Measurement System (OMS), developed at IIT Kharagpur. The OMS facility works under vacuum environment, in which the test samples are exposed to vacuum conditions over a sufficient period of time. The outgassing measurements for the composite samples were obtained using pressure-rise technique. These studies are useful to quantify the outgassing rate of composite materials under vacuum conditions and to suggest them for manufacturing composite torque tubes used in HTS motors.

• Journal of Plant Biotechnology
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• 제7권2호
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• pp.113-121
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• 2005

The objective of this study was to identify the major parameters controlling DNA delivery by particle bombardment to immature embryos of Chinese spring wheat (Triticum aestivum L.). Efficiency of DNA (uidA gene) delivery was assessed by transient GUS (${\beta}$-glucuronidase) expression in bombarded tissues. Of the parameters analyzed, acceleration pressure, bombardment distance, chamber vacuum pressure, bombardment times, osmotic conditioning of culture had a remarkable influence on transient gene expression. A bombardment procedure suitable for Chinese spring wheat cultivars was developed which allowed high-efficiency DNA delivery combined with reduced damage to target tissues. The high efficiency made the system practical for wheat genetic transformation research and accelerating wheat breeding programs.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.229-234
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• 2007

Microscale heat transfer and microfluidics have become increasingly important to overcome some very complex engineering challenges. The use of very small passages to gain heat transfer enhancement is a well documented method for achieving high heat flux dissipation. As the passage size is decreased, the heat transfer performance increases but the pressure drop increases sharply when the passage size is reduced. In this study, the performance evaluation of micro plated heat exchangers under the counter flows with straight, V-shaped and Y-shaped channel are carried out.