• 멤브레인
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• 제28권5호
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• pp.320-325
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• 2018

FASs (fluoroalkylsilanes)로 표면 개질한 소수성 막에 대한 부탄올/물, 이소프로판올/물 용액의 수착(sorption)량을 측정하였으며 이들 수착 특성을 Hansen 용해도 파라미터를 이용하여 해석하였다. 부탄올의 수착량이 이소프토판올보다 많았으며, 이는 부탄올의 용해도 파라미터(${\delta}_t=20.4$)와 FASs 소수성 막의 용해도 파라미터(${\delta}_t=16.9$)와의 차이가 이소프로판올 (${\delta}_t=24.6$)과의 차이보다 작기 때문인 것으로 설명할 수 있다. 극성력(${\delta}_p$) 측면에서 살펴보면, FASs 극성력(${\delta}_p=4.6$)과 부탄올의 극성력(${\delta}_p=6.3$)과의 차이가 FASs 극성력(${\delta}_p=4.6$)과 이소프로판올의 극성력(${\delta}_p=9.0$)과의 차이보다 작다. 이는 부탄올-FASs 간의 극성력 차이가 이소프로판올-FASs 간의 극성력 차이보다 작아서 부탄올-FASs 간의 상호인력이 크다는 것을 의미하며, 수착량이 크게 나타나는 결과를 설명할 수 있다. 본 실험결과로부터 막에 대한 알코올의 수착특성, 용매에 대한 용질의 용해도 등을 분석하는데 용해도 파라미터를 이용할 수 있음을 알 수 있다.

• 센서학회지
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• 제27권2호
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• pp.99-104
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• 2018

A micro electromagnetic actuator with high vibration efficiency is proposed for use in an implantable hearing device. The actuator, which can be implanted in the middle ear, consists of membranes based on the stainless steel 304 (SUS-304), and other components. In conventional actuators, in which a thick membrane and a silicone elastomer are used, the size reduction was difficult. In order to miniaturize the size of the actuator, it is necessary to reduce the size of the actuation potion that generates the driving force, resulting in reduction of the electromagnetic force. In this paper, the electromagnetic actuator is further miniaturized by the metal membrane and the vibration amplitude is also optimized. The actuator designed according to the simulation results was fabricated by using micro-electro-mechanical systems (MEMS) technology. In particular, a $20{\mu}m$ thick metal membrane was fabricated using the erosion process, which reduced the length of the actuator by more than $400{\mu}m$. In the experiments, the vibration displacement characteristics of the optimized actuator were above 400 nm within the range of 0.1 to 1 kHz when a current of $1mA_{rms}$ was applied to the coil.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2010년도 정기 학술발표대회
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• pp.102.1-102.1
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• 2010

대체수자원 중 막여과 기술에 대한 관심이 지속적으로 높아지고 있다. 하지만, 이러한 막여과 기술에는 fouling이 발생시 효율저감, flux저감, 소모에너지 증대 등 문제점이 발생한다. 이러한 fouling저감을 위해 막 표면특성분석을 통한 기초연구가 필요하다고 보고 이 연구를 진행하였다. AFM을 이용하여 CML입자와 막의 상호작용을 통해 초기 막오염 경향을 예측할 수 있다.

• 한국가스학회지
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• 제14권2호
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• pp.40-46
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• 2010

본 연구에서는 기존 멤브레인식 LNG 저장탱크의 측정장치와 안전장치에 대한 고찰과 분석을 통해 초대형 멤브레인 식 LNG 저장탱크에 적합한 새로운 통합제어안전관리시스템 연구를 수행하고자 한다. 통합제어안전관리시스템은 기존에 단수로 설치한 압력계를 추가하고, 기존의 LNG 저장탱크에는 없는 변위센서와 하중센서를 내부탱크와 예응력 콘크리트 구조물 사이를 관통하는 강재앵커에 새로이 설치함으로써 초대형 LNG 저장탱크의 안전성과 효율성을 향상시키는 역할을 담당할 것으로 예상된다. 변위센서와 하중센서는 멤브레인 패널의 파손여부, 내부탱크로부터 발생된 LNG 누설의 단서를 제공하게 될 것이다. 기존의 누설센서는 내부탱크 뒤편의 보냉재 공간에 설치한 온도센서에 의해 LNG 누설이라는 신호를 보낼 때까지도 멤브레인 패널의 손상에 관련된 적절한 정보를 제공하지 못할 수 있다. 결국 새로운 통합제어안전관리시스템은 온도, 압력, 변위량, 하중, LNG의 밀도 데이터를 수집하고 분석하기 위한 것으로, 탱크시스템의 안전성과 내부탱크의 누설을 제어하기 위한 시스템이다. 또한, 디지털 데이터는 멤브레인 패널의 안전성에 관련된 변위량과 하중, LNG의 액위와 밀도, 쿨다운 공정, 누설, 압력 등을 제어하기 위해 측정된다.

• 한국막학회:학술대회논문집
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• 한국막학회 1995년도 춘계 총회 및 학술발표회
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• pp.34-35
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• 1995

The unique feature of pervaporation is the mass transfer from a liquid phase to a vapor phase through a non-porous polymeric membrane. When a liquid mixture is brought into contact with a membrane at one side, it is sorbed into the membrane. Due to a driving force applied across the membrane, the sotbed liquid molecules permeate through the membrane and evaporate at the downstream side of the membrane. In pervaporation the permeated species are usually removed from the downstream side under a relatively low vapor pressure, for example by evacuation with a vacuum pump. As far as this condition is fulfilled, the evaporation step can be considered to be much faster than sorption or diffusion. Hence evaporation does not contribute to permselectivity. Therefore the separation by pervaporation results from the differences in the preferential sorption of the individual components of a mixture into the membrane together with the diffusion rates through the membrane. This postulation implies that both sorption and diffusion phenomena have to be accounted for to understand the physico-chemical nature of the pervaporation separation process.

• Membrane and Water Treatment
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• 제10권5호
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• pp.381-385
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• 2019

Surface modification is very efficient and scalable approach to achieve improved membrane performance. We treated Reverse Osmosis Thin Film Composite (TFC RO) membrane with various concentrations of Polyethylene Glycol (PEG), a hydrophilic polymer after activation with sodium hypochlorite. This treatment resulted in an increment of the water flux by 43% and the salt rejection by 2.36% for the 3000 mg/l PEG-treated membrane. Further, these PEG-treated membranes were exposed to a mixture of 3000 mg/l PEG and 1000 mg/l sodium hypochlorite for 1 hour. Further modification of this membrane by PEG and sodium hypochlorite mixture increased the water permeance up to 133% when compared with the virgin TFC RO membrane. We characterized the treated membranes to understand the changes in wettability by contact angle analysis, changes in surface morphology and roughness by scanning electron microscope (SEM) and atomic force microscope (AFM) analysis.

• 한국공간구조학회논문집
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• 제19권1호
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• pp.109-116
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• 2019

In this paper, the shape adjustment algorithm of the spoked wheel cable structures with retractable membrane system is studied. The initial tension of the membrane or cable is necessary to form the structure and its value is determined by the design shape. However, due to internal and external environmental influences, its shape may be different from the initial designed shape. In the case of the cable structures covered in this study, tension adjustment is necessary to maintain the designed shape because it influences the tension of the cable depending on the state of the retractable membrane. Therefore, we proposed an adjustment algorithm of an initial shape based on the force method. The effectiveness and validity of the methodology were examined through the applicable cable structures. The results of the shape adjustment analysis of the symmetric spoked wheel cable model were reliable and accurate results were obtained.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.907-912
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• 2001

KOGAS had developed the Ring-knot membrane for LNG storage tank. But we found that some modifications were needed in using the Ring-knot membrane for the commercial LNG storage tanks. So, both analytical and experimental studies have been performed to investigate the strength of the new membrane and the reaction force at the anchor point. Using nonlinear FEM code and experiments, the stress analysis of the new corrugated membrane shapes subject to the cryogenic liquid pressure and thermal loading are performed to ensure the stability and fatigue strength of the new membrane. This paper reports on the results of investigations into this new type of membrane.

• 한국유체기계학회 논문집
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• 제9권2호
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• pp.19-24
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• 2006

Nano fountain-pen is a novel device to make the constant patterning in micro process using new designed probe. Fountain-pen nanolithography (FPN) is applied for constant supply of liquid in conjunction of patterns and surface variation in the micro process. In this study, nuo fountain-pen is composed with reservoir, micro channels, tip and scondary chamber. Instead of traditional method only using capillary force, liquid can be definitely and exactly injected with membrane pumping by the repulse force of tip. It is dfficult to perform experiments in the micro range so that we carried out a numerical analysis for internal flow, using a commercial code, FlUENT, The velocity, pressure and flow rate are obtained under laminar, unsteady, three-dimensional incompressible flow with no-slip condition, and results are graphically described.

• 한국공간구조학회논문집
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• 제5권2호
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• pp.81-87
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• 2005

The Space structures may have large freedom in scale and form. And especially Hybrid structures are received much attention from the view points of their light weight and aesthetics. Hybrid systems are stable structures which are reticulated spatial structures composed of compressive straight members, struts and cables and Membranes. In this paper, The Hybrid Unit System are suggested using the Membrane and Cable elements based on the Tensegrity Unit system. Also, The Hybrid System of double-layered single curvature is presented. We analyze the force density method allowing form-finding for Tensegrity systems. And We analyze the shape analysis by the LARSH which is the program for nonlinear analysis.