• 지질공학
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• 제5권1호
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• pp.105-113
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• 1995

광대역 방해신호가 수신되는 센서 또는 안테나 어레이에는 어레이 성능을 향상시키기 위하여 각 방해신호 방향에 광대역 영점(null)을 형성하는 것이 바람직하다. 광대역 영점을 효과적으로 형성하는 한 방법은 미분 영점을 사용하는 것이다. 어레이 계수와 감지기 위치의 무작위 오류가 있는 어떤 조건이 주어진 선형 어레이에서의 미분영점의 성능을 논의하며 컴퓨터 실험 결과를 제시한다.

• 환경위생공학
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• 제13권1호
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• pp.147-156
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• 1998

A synthesis process for PZT powder using $NH_{3}$ gas as a precipitator in a bubble column reactor was experimentally successful in develope a production process of piezoelectric ceramic PZT powder. Also as a reaction by coprecipitation, the crystalized PZT ceramic powder at the condition of over pH 9 could be attained. The time needed for reaction on the condition of $NH_{3}$ gas flow rate = 0.5 1/min, Ar gas flow rate = 2.0 1/min. Feed flow rate = 2.33 ml/sec was less than five minutes, so it could synthesize PZT powder for such a few moments. And the synthesized PZT powder was $0.17{\mu}m$ in diameter on an average.

• Applied Science and Convergence Technology
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• 제24권6호
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• pp.219-223
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• 2015

Enhancement of the surface hydrophobicity of polydimethylsiloxane (PDMS) thin films deposited on substrates covered with titanium dioxide ($TiO_2$) nanospheres was studied. First, a low-temperature solution-phase method using polyvinylpyrrolidone (PVP) as a surface capping agent and a water/dimethylformamide (DMF) mixture as the reaction medium was used to synthesize monodisperse $TiO_2$ nanospheres. It was possible to easily control hydrolysis rate of the Ti-precursors and the size of the synthesized nanospheres by varying the amount of PVP and the volume ratio of the solvent mixture. Spray coating of the synthesized $TiO_2$ nanospheres under the PDMS film increased the water contact angle of the film surface to $150.3^{\circ}$. This simple treatment can modify the surface morphology at a nanometer scale without any long or complicated nanoprocess; hence, the surface enters the superhydrophobic Cassie-Baxter regime.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.184-186
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• 2009

Composites of LSCF($La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-\delta}$ and CGO(gadolinium doped ceria) is an efficient candidate cathode material with CGO electrolytes. In this study, LSCF with exact perovskite structure was synthesized by using solid state reaction(SSR) method. The optimized temperature to synthesize $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-\delta}$ with rhombohedral structure. was $1100^{\circ}C$. The polarization resistance of the LSCF/CGO(50:50 wt.%) was smaller than those of other composite cathodes. The analysis of the EIS data of LSCF/CGO suggests that the diffusion and adsorption-desorption of oxygen can be the key process in the cathodic reaction of SOFC using LSCF/CGO as cathode material.

• Archives of Pharmacal Research
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• 제21권1호
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• pp.73-75
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• 1998

In summary, six 4-substituted-1-azzanthraquinones were designed and synthesized using hetero Diels-Alder reaction as a key step. Although a great number of reaction conditions for benzylic bromination were examined, this step need to be improved for the efficient synthesis of the related analogues. 4-Bromomethyl-1-azzanthraquinone 6 may have potential for the treatment of tumors resistant to the doxorubicin. The compounds 9 and 10 containing the latent alkylating functionality may need further in depth biological evaluation. Work is in progress to design, synthesize, and evaluate additional compounds in this and related systems.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.912-915
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• 2002

It has been known that general velocity and force of a rigid body in space can be described in forms of a twist and a wrench by use of screws. However, the geometrical meaning of acceleration has not been clearly disclosed. It has been a normal practice to analyze or synthesize the acceleration effect of manipulator using some complex mathematical equations, which do not represent any geometrical meanings. In other words, such a technique doesn't clearly provide information about the overall acceleration state of manipulator at that instant. In this study, the geometrical meaning of acceleration of a rigid body has been investigated and thereby a geometrical procedure which can be applied to inverse acceleration analysis of a general non-redundant manipulator is presented as an application.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1998년도 Proceedings of UNESCO-internetwork Cooperative Regional Seminar and Workshop on Bioassay Guided Isolation of Bioactive Substances from Natural Products and Microbial Products
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• pp.189-189
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• 1998

Tissue factor (TF) is a cell surface receptor of coagulation factor Ⅶ and is the principal initiator of the vertebrate coagulation cascade. TF is found in high levels in some organs such as brain, lung and placenta, whereas blood monocytes, endothelial cells contain only trivial amount of TF when quiescent, and is stimulated to synthesize TF by infections or vascular lesions. TF is reported to be found in high levels in atherosclerotic plaques, cancer cells. TF activation in various cells in many infectious or immunologic diseases tells us the physiologic importance of TF. We screened many edible vegetables for TF inhibitor, by measuring the prothrombin time to detect the TF activity, and we picked Aster scaber to isolate the TF inhibitory substance. Aster scaber showed two kinds of anti thrombotic activity, one is TF inhibition and the other is elongation of plasma recalcification time. The anti thrombotic substances were found to be saponins which has echinocystic acid as aglycone.

• 한국정밀공학회지
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• 제15권3호
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• pp.88-98
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• 1998

In many automatization applications, a rigid body is required to go forward and backward repeatedly through a set of given position/orientations precisely while a crank is rotated. Such a motion can be generated by 6 bar mechanism adding a dyad to a 4 bar mechanism. If this is the case for 3 position synthesis of the 4 bar mechanism, the feasible solution area for designing the 4 bar mechanism will be limited over the general solution area. This paper proposes a procedure to synthesize 4 bar mechanism to be used to generate the required motion. It is found that the only input crank of the 4 bar mechanism should be limited to satisfy the condition. And the feasible design area for the circle point/ center point of the input crank is identified so that design of the undesired mechanism could be avoided. The method is tested and the results are shown.

• 한국진공학회지
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• 제7권1호
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• pp.72-76
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• 1998

본 연구에서는 방전내에서 활성화된 라디칼의 반응을 촉진시키는 플라즈마중합을 통하여 기능성 유기박막을 합성하기 위해 새로운 형태의 유동가스형 반응장치를 개발하였 다. 중합을 위해서 스티렌 모노머를 사용하였으며 분자구조와 분자량 분포에 대한 분석을 행하였다. 제작된 플라즈마중합막은 우수한 성능의 전자빔 레지스트로서 평가되었다. 새로운 플라즈마 반응장치를 이용하여 제작된 박막의 감도는 습식공정에 의해 제작된 레지스트의 감도에 비해서 향상되었으며 깨끗한 패턴이 성공적으로 제작되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.531-531
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• 2012

So many groups have been researching the green quantum dots such as InP, InP/ZnS for overcoming the semiconductor nanoparticles composed with heavy metals like as Cd and Pb so on. In spite of much effort to keep up CdSe quantum dots, it does not reach the good properties compared with CdSe/ZnS quantum dots. This quantum dot has improved its properties through the generation of core/shell CdSe/ZnS structure or core/multi-shell structures like as CdSe/CdS/ZnS and CdSe/CdS/ CdZnS/ZnS. In this research, we try to synthesize the InP multi-shell structure by the successiveion layer absorption reaction (SILAR) in the one pot. The synthesized multi-shell structure has improved quantum yield and photo-stability. To generate white light, highly luminescent InP multi-shell quantum dots were mixed with yellow phosphor and integrated on the blue LED chip. This InP multi-shell improved red region of the LEDs and generated high CRI.