• Korean Chemical Engineering Research
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• 제48권5호
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• pp.568-573
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• 2010

본 연구에서는 polyester 섬유표면에 활성기를 부여하기 위한 전처리제로 isocyanate를 이용하여 농도에 따른 접착력을 평가하였다. 이 후 HNBR compound와 polyester fabric의 접착 시 접착력이 우수한 RFL 용액용 latex 선정 및 F/R mole ratio, F/R resin/latex 무게 비에 따른 실험을 진행하였다. 그 결과 전처리제의 농도가 7 wt%인 경우 가장 높은 접착력을 나타내었으며, RFL 용액용 latex로는 HNBR 컴파운드와 상용성이 높은 NBR latex가 우수한 결과를 나타내었고 F/R mole ratio, FR resin/latex 무게비가 각각 1/1, 20%일 때 가장 높은 접착력을 나타내었다. 또한, peel test와 FTIR 분석을 이용해 RF resin의 열처리 온도에 따른 접착강도와 spectra의 peak 변화를 평가해 본 결과 최적의 열처리 온도는 $200^{\circ}C$이었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.221-221
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• 2013

Striving to replace the well known silicon nanocrystals embedded in oxides with solution-processable charge-trapping materials has been debated because of large scale and cost effective demands. Herein, a silicon quantum dot-polystyrene nanocomposite (SiQD-PS NC) was synthesized by postfunctionalization of hydrogen-terminated silicon quantum dots (H-SiQDs) with styrene using a thermally induced surface-initiated polymerization approach. The NC contains two miscible components: PS and SiQD@PS, which respectively are polystyrene and polystyrene chains-capped SiQDs. Spin-coated films of the nanocomposite on various substrate were thermally annealed at different temperatures and subsequently used to construct metal-insulator-semiconductor (MIS) devices and thin film field effect transistors (TFTs) having a structure p-$S^{++}$/$SiO_2$/NC/pentacene/Au source-drain. C-V curves obtained from the MIS devices exhibit a well-defined counterclockwise hysteresis with negative fat band shifts, which was stable over a wide range of curing temperature ($50{\sim}250^{\circ}C$. The positive charge trapping capability of the NC originates from the spherical potential well structure of the SiQD@PS component while the strong chemical bonding between SiQDs and polystyrene chains accounts for the thermal stability of the charge trapping property. The transfer curve of the transistor was controllably shifted to the negative direction by chaining applied gate voltage. Thereby, this newly synthesized and solution processable SiQD-PS nanocomposite is applicable as charge trapping materials for TFT based memory devices.

• Carbon letters
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• 제12권4호
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• pp.207-217
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• 2011

We discuss the influence of few-walled carbon nanotubes (FWCNTs) treated with nitric acid and/or sulfuric acid on field emission characteristics. FWCNTs/tetraethyl orthosilicate (TEOS) thin film field emitters were fabricated by a spray method using FWCNTs/TEOS sol one-component solution onto indium tin oxide (ITO) glass. After thermal curing, they were found tightly adhered to the ITO glass, and after an activation process by a taping method, numerous FWCNTs were aligned preferentially in the vertical direction. Pristine FWCNT/TEOS-based field emitters revealed higher current density, lower turn-on field, and a higher field enhancement factor than the oxidized FWCNTs-based field emitters. However, the unstable dispersion of pristine FWCNT in TEOS/N,N-dimethylformamide solution was not applicable to the field emitter fabrication using a spray method. Although the field emitter of nitric acid-treated FWCNT showed slightly lower field emission characteristics, this could be improved by the introduction of metal nanoparticles or resistive layer coating. Thus, we can conclude that our spray method using nitric acid-treated FWCNT could be useful for fabricating a field emitter and offers several advantages compared to previously reported techniques such as chemical vapor deposition and screen printing.

• 공업화학
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• 제20권6호
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• pp.622-627
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• 2009

알칼리 수용액에 현상이 가능한 감광성 수지재료와 전도성 카본블랙 필러를 이용하여 포토 패터닝이 가능한 폴리머 후막 저항 페이스트를 제조하고 평가하였다. 감광성 수지로는 인쇄회로기판의 보호층으로 주로 사용되는 photo solder resist(PSR)를 사용하여 자외선에 의한 노광 및 알칼리 수용액에의 현상이 가능하게 하였다. 감광성 폴리머 저항 페이스트를 제작한 후, PCB 테스트 보드를 이용하여 후막저항체의 전기적 특성을 평가하였다. 카본블랙의 첨가량에 따라 시트저항은 감소하였으나, 과량 첨가시에는 현상성에 한계를 나타내었다. 재경화에 따라서 시트저항이 감소하였으며, 카본블랙의 첨가량이 많을수록 그 변화율은 작게 나타났다. 포토공정을 적용하여, 미세 패터닝된 meander형 후막저항체를 제조할 수 있었고, 이 방법을 통하여 적은 면적에도 시트저항의 수십 배에 달하는 큰 저항값을 구현할 수 있었다.

• 분석과학
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• 제12권3호
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• pp.203-208
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• 1999

살리실산 및 그 유도체들의 이온쌍 고성능 액체크로마토그래피 용리거동을 이동상 중 이온쌍 시약(tetrabutylammonium chloride, TBACl)의 농도를 변화시키면서 용량인자, k'를 측정함으로서 고찰하였다. 이동상의 pH 및 TBACl의 농도가 증가함에 따라 시료들의 k'는 증가하였다. 살리실산 정량의 최적 이동상 조건은 pH 7.2에서 20 mM TBACl을 함유한 메탄올 용액($MeOH:H_2O$ 30:70), p-아미노살리실산(PAS)은 40 mM TBACl을 함유한 메탄올 용액($MeOH:H_2O$ 20:80) 이었다. 머무름 거동의 관찰로부터 발견한 최적 조건에서 몇 가지 유도체들을 분리하였으며 아울러 아스피린과 결핵 치료제 중 살리실산 유도체들의 함량을 조사하였다.

• 폴리머
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• 제28권6호
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• pp.494-501
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• 2004

시클로부탄-1,2,3,4-테트라카복실산 이무수물, 2-(메타크릴로일옥시)에틸-3,5-디아미노벤조에이트 및 1,3-비스(3-아미노프로필)-1,1,3,3-테트라메틸디실록산을 N-메틸-2-피롤리돈 하에서 용액 중합 반응시켜 알칼리 수용액에서 현상이 가능할 뿐만 아니라 가시광선 영역에서 우수한 광투과성을 보이는 신규 감광성 폴리이미드 전구체인 폴리암산 (PAA-0)을 제조하였다. 광개시제의 존재 하에서 노광 후 열경화된 폴리이미드 박막은 2.38 wt%의 테트라메틸암모니움 히드록사이드 수용액에 용해되지 않는 특성을 보였으며, 이를 이용하여 광에 의한 미세 화상 형성 연구를 수행하였다. 폴리이미드 전구체 박막의 광반응에 적합한 광개시제는 2, 2-디메톡시-2-페닐아세토페논임을 알 수 있었고, 최적 광량은 400∼600 mJ/$\textrm{cm}^2$의 범위에 있음이 확인되었다. 감광성 폴리이미드 전구체는 25$0^{\circ}C$의 온도에서 50분간 열경화시킴으로써 투명한 폴리이미드 박막으로 전환이 되었으며, 유기용제를 비롯한 포토레지스트 제거제에 대한 우수한 내용제성 및 가시광선영역에서의 우수한 광투과 특성을 나타내었다.

• Corrosion Science and Technology
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• 제7권1호
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• pp.13-15
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• 2008

Aiming at the corrosion circumstances and corrosion prevention needs of downhole oil tubes, series protective coatings for downhole oil tubes have been developed in the authors' laboratory, including a baked type coating YG-01 and an air curing type coating YG-03, etc. The performance investigation of the coatings has been done for testing their corrosion resistance, mainly including salt fog test, immersion test in oil-field waste water and various acid solutions, high temperature and high pressure test in alkali solution or $H_2S/CO_2$ environment, as well as some other performances. The investigation results show that oil tube anti-corrosion coatings developed here can endure over 4000 hrs salt fog test, over 1000 hrs immersion in various acid solutions at room temperature and in boiling oil-field waste water. In addition, the coatings can keep intact after experiencing test in alkali solution under 70 MPa pressure at $150^{\circ}C$ for 24 hrs, and in simulative sour gas environment under the total pressure of 32 MPa ($P_{H_{2}S}=3.2MPa$, $P_{CO_{2}}=3.2MPa$) at $90^{\circ}C$ for 168 hrs, which show that the coatings can be used for corrosion prevention in downhole environments with specific high temperature and high pressure, such as sour gas wells. The other testing results show the oil tube protective coatings have excellent comprehensive performance.

• 대한한방부인과학회지
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• 제18권4호
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• pp.72-84
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• 2005

Purpose : This study was carried out to investigate the relaxational response to the water extract of Sobokchukeo-Tang(SCT) in isolated uterine muscle in rats. Methods : Segments of uterine muscle obtained from female rats immediately after delivery were mounted in organ baths superfused on a polygraph. The effects of SCT on the tension of potassium induced contracture were studied in rat uterine smooth muscles. All experiments were performed in Krebs-Henseit solution which was aerated with 100% oxygen and kept at $37^{\circ}C$. Results : KCI did not produce contraction in calcium-free solution, but $CaCl_2$ induced concentration-dependent contraction after depolarizing with KCI. SCT inhibited the tonic contraction of uterine muscle as dose dependent manner. And when SCT was pretreated in calcium-free medium, it showed more powerful relaxational effect. The effect of 10mg/ml concentration of SCT was equal to that of 9nM and 70nM of nifedipine and verapamil and the relaxational effect of SCT on rat uterine muscle can be assumed to be concerned with the action of cyclic AMP. But the action mechanism of relaxation on the rat uterine muscles were concerned with the calcium channel. Conclusion : From this study we could suggest that the relaxtional effect of SCT on uterine muscle be available to preventing and curing dysmenorrhea.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.893-896
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• 2008

본 연구는 황산염 환경하에서 메타카올린을 사용하여 제작된 시멘트 모르타르의 기초물성을 평가하기 위한 연구이다. 최근 열악한 환경에 노출되는 콘크리트 구조물이 증가함에 따라 콘크리트의 내구성에 대한 관심이 늘어나고 있다. 광물성 혼화재료를 첨가할 경우 콘크리트 내부의 조직을 치밀하게 하여 내구성을 좋게하는 방안이 있으며 현재에도 실리카흄, 플라이애쉬, 슬래그와 같은 기존의 광물질 혼화재료 이외에 새로운 혼화재료에 대한 연구가 활발히 진행되고 있는 실정이다. 따라서 본 연구에서는 열악한 환경에 노출된 콘크리트 열화에 대하여 아직 그 연구가 미비한 광물질 혼화재료인 메타카올린을 5%, 10%, 15%로 치환하여 시멘트 모르타르로 시편을 제작하였고, 이를 28일 표준양생을 시켜 담수, 해수, 10% 황산나트륨용액, 10% 황산마그네슘 용액에서 28일, 60일, 90일, 180일, 270일, 365일 동안 촉진양생 시켜 다양한 시편의 기초물성에 대한 실험을 수행하였다. 또한 현재 널리 쓰이고 있는 광물질 혼화재료인 실리카흄과 플라이애쉬를 가지고 같은 방법으로 실험을 한 후 메타카올린을 치환한 시편과의 비교 분석을 통하여 메타카올린의 내구적 성능을 평가하고자 한다.

• Journal of Magnetics
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• 제20권2호
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• pp.103-109
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• 2015

In this study, the authors attempted to produce a medical radiation shielding fiber that can be produced at a nanosize scale and that is, unlike lead, harmless to the human body. The performance of the proposed medical radiation shielding fiber was then evaluated. First, diamagnetic bismuth oxide, an element which, among elements that have a high atomic number and density, is harmless to the human body, was selected as the shielding material. Next, 10-100 nm sized nanoparticles in powder form were prepared by ball milling the bismuth oxide ($Bi_2O_3$), the average particle size of which is $1-500{\mu}m$, for approximately 10 minutes. The manufactured bismuth oxide was formed into a colloidal solution, and the radiation shielding fabric was fabricated by curing after coating the solution on one side or both sides of the fabric. The thicknesses of the shielding sheets prepared with bismuth oxide were 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and 1.0 mm. An experimental method was used to measure the absorbed dose and irradiation dose by using the lead equivalent test method of X-ray protection goods presented by Korean Industrial Standards; the resultant shielding rate was then calculated. From the results of this study, the X-ray shielding effect of the shielding sheet with 0.1 mm thickness was about 55.37% against 50 keV X-ray, and the X-ray shielding effect in the case of 1.0 mm thickness showed shielding characteristics of about 99.36% against 50 keV X-ray. In conclusion, it is considered that nanosized-bismuth radiation shielding fiber developed in this research will contribute to reducing the effects of primary X-ray and secondary X-ray such as when using a scattering beam at a low level exposure.