• Korean Journal of Materials Research
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• v.12 no.9
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• pp.747-749
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• 2002

Hydroxyapatite powders were prepared after heating at $1250^{\circ}C$ by the direct reaction using oyster shells and $H_3$$PO_4$. Properties of hydroxyapatite powders were investigated as XRF, XRD, DTA, FT-IR, SEM. Only hydroxyapatite was observed in XRD powders which was heated at $1250^{\circ}C$ for 2 hours and there was no remained CaO in that sample. And the results of FT-IR of sample was confirmed hydroxyapatite. Sample was agglomerated together, but needle shape morphology was observed in powders heated at $1250^{\circ}C$.

• Journal of the Korean Ceramic Society
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• v.28 no.8
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• pp.647-653
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• 1991

In order to synthesize fine AlN powder by the direct nitridation of Aluminum metal power added LiF and BaF2 as additives was heated at 150$0^{\circ}C$ for 3 hrs. in nitrogen gas with flow rate of 20 mι/sec. Additives are promoted the nitridation by prevented the aggromerate of powders when 3% LiF and 2% BaF2 were added to Al metal powder. Rate of nitridation was about 100% and average size of AlN powders were very fine such as 0.3 ${\mu}{\textrm}{m}$. Specific surface area of synthesized AlN powder was 3.95$m^2$/g and also O2 and N2 contents were 2.595% and 33.25%, respectively.

• Proceedings of the Korean Printing Society Conference
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• 1995.11a
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• pp.23-25
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• 1995

• Journal of Pharmaceutical Investigation
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• v.19 no.3
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• pp.117-121
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• 1989

A metal complex, copper (II) L-proline was chemically bound to ethylene glycol dimethacrylate and divinylbenzene crosslinked chloromethylated polystyrene and they were used as chiral chelate resin matrix for column chromatography to resolve enantiomers of DL-amino acids. The L-enantiomers eluted first and the degree of resolution on the polymer crosslinked with ethylene glycol dimethacrylate was superior to the polymer crosslinked with divinylbenzene.

• Journal of Energy Engineering
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• v.10 no.1
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• pp.40-48
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• 2001

디젤엔진에 적합한 환경 친화적 연료로 평가받고 있는 디메틸에테르(DME)를 기존의 메탄올 탈수화에 의한 간접법 대신 합성 가스로부터 직접 합성법으로 제조하였다. 합성가스에서 메탄올을 합성하는 경우에 비해 화학 평형 상의 이점 때문에 DME를 합성하는 것이 경제적이며 이는 실험 결과와 일치하였다. 기상 반응기에서 메탄올 탈수촉매의 부가에 의한 메탄올 환산 생산량은 메탄올 합성촉매에 의한 생산량에 비해 두 배 이상의 증가를 보인다. 메탄올 탈수촉매를 Cu로 개질한 효과는 없었으며, 메탄올 탈수촉매로서 순수 감마알루미나가 가장 우수한 반응성을 보였다. 반응 조건이 25$0^{\circ}C$, 30atm일 때 고려된 GHSV 범위에서 촉매 적정 혼합비는 7:3, 합성 가스의 조성비는 $H_2$/CO=1일 때 가장 좋은 선택도와 수율을 나타내었다.

• Journal of Energy Engineering
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• v.10 no.1
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• pp.49-54
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• 2001

최근 자동차용 청정 연료로서의 이용 가능성으로 주목받는 디메틸에테르를 액상 혼합 반응기에서 직접 합성 가스로부터 합성하였다. 메탄올 함성촉매와 감마알루미나의 혼성촉매를 사용한 결과, $H_2$/CO=1일 때, 메탄올 함성 촉매와 탈수촉매의 비가 8:2인 경우, 가장 높은 메탄옥 환산 생산량을 보였다. 또한 공간속도의 변화에 따른 디메틸에테르, 메탄올, 이산화탄소, 메탄 등 각 생성물에 대한 선택도의 변화는 거의 없이 일정하였다. 메탄옥 합성 반응 촉매만을 사용한 경우, 생성물 중 각 성분의 선택도는 반응가스의 공간속도에 따라 달라졌는데, 반응가스의 공간속도가 작아지면 생성물 중 디메틸에테르의 선택도는 변화가 없었으나, 이산화탄소의 발생량이 많고 메탄올의 생성이 적어졌다. 동일한 반응 조건에서 액상 반응과 시강 반응을 비교한 결과, DME 수율이 액상의 경우가 더 높았다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.92.1-92.1
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• 2013

Molecular electronics has been the subject of intese research for many years because of the fundamental interest in molecular charge transport and potential applications, such as (bio)nanosensors and molecular memory devices. Molecular electronics requires a method for making reliable eletrical contacts to singlemolecules. To date, several approaches have been reported: scanning-probe microscopy, mechanical break junctions, nano patterning, and direct deposition of electrode on a self-assembled monolayers. However, most methods are laborious and difficult for large-scale application and more importantly, cannot control the number of moleucles in the junction. Recently, DNA has been used as a template for metallic nanostructures (e.g., Ag, Pd, and Au nanowires) through DNA metallization process. Furthermore, oligodeoxynucleotides have been tethered to organic molecules by using conventional organic reactions. Collectively, these techniques should provide an efficient route toward reliable and reproducible molecular electronic devices with large-scale fabrication. Therefore, I will present a paradigm for the fabrication of moleuclar electronic devices by using micrometer-sized DNA-singe organic molecule and DNA triblock structures.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.265.2-265.2
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• 2013

We fabricate poly(3,4-ethylenedioxythiopene patterns using liquid-bridge-mediated nanotransfer (LB-nTM) printing via vapor phase polymerization (VPP). LB-nTM printing method can simultaneously enable the synthesis, alignment and patterning of the nanowires from molecular ink solutions. Two- or three-dimensional complex structures of VPP-PEDOT were directly fabricated over a large area using many types of molecular inks. VPP method is a versatile technique that can be used to obtain highly conducting coatings of conjugated polymer on both conducting and non-conducting substrates. The PEDOT patterns has analyzed crystallinity from X-ray diffraction pattern and select-area diffraction patterns. In addition, the PEDOT pattern has high conductivity compared other conducting polymers.

• Journal of the Mineralogical Society of Korea
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• v.3 no.2
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• pp.89-97
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• 1990

To examine how London energy controls the c-dimensions of phyllosilicates, London energy, as well as Coulomb and Pauli repulstion energy was calculated as a function of d(001) for 1M and d(002) for 2M 1 phyllosilicates. London and Pauli repulstion energy calcualtion use a direct interaction calculation method and Coulomb energy calculation adopts Fourier synthesis method. The energy calculations show that Coulmb and Pauli repulsion energy dominantly control the c-dimensions of phyllosilicates having the interlayer cationss, i.e., the layer charges. On the other hand, if phyllosilicates have no interlayer cations, London energy is solely responsible for holding the layers and maintain the c-dimensions. The significance of London energy in determining the c-dimensions of phyllosislicates de-creases as the layer charge increases. When the layer charge is lower than one equivalent on the basis of Oη(OH)2 formula, London energy plays an important role in determing the c-dimensions. however, if the layer charge is higher than one equivalent, London energy becomes insignifi-cant in determining the c-dimension.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.12
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• pp.3782-3791
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• 1996

A great deal of effert has been invested in upgrading the performance and the efficiency of mechanical structures. Using experimental modal analysis(EMA) or finite element analysis(FEA) data of mechanical structures, this performance and efficiency can be effectively evaluated. In order to analyze complex structures such as automobiles and aircraft, for the sake of computing efficiency, the dynamic substructuring techniques that allow to predict the dynamic behavior of a structure based on that of the composing structures, are widely used. By llinking a modal model obtained from EMA and an analytical model obtained from FEA, the best conditioned structures can be desinged. In this paper, a new algorithm for structural dynamic modification-SRFSM (substructure response function sensitivity method) is proposed by linking frequency responce function synthesis and response function sensitivity. A mehtod to obtain response function sensitivity using direct derivative of mechanical impedance, is also used.