• Archives of Pharmacal Research
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• 제21권4호
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• pp.481-484
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• 1998

In activated macrophages the inducible form of nitric oxide synthase (i-NOS) generates high amounts of toxic mediator, nitric oxide (NO) which contributes to the circulatory failure associated with septic shock. A sesquiterpene lactone compound (yomogin) isolated from medicinal plant Artemisia princeps Pampan inhibited the production of NO in LPS-activated RAW 264.7 cells by suppressing i-NOS enzyme expression. Thus, yomogin may be a useful candidate for the development of new drugs to treat endotoxemia and inflammation accompanied by the overproduction of NO.

• 한국재료학회지
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• 제15권1호
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• pp.6-13
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• 2005

Copper based leadframe sheets were immersed in two kinds of hot alkaline solutions to form brown-oxide or blackoxide layer on the surface. The oxide-coated leadframe sheets were molded with epoxy molding compound (EMC). After post mold curing, the oxide-coated EMC-leadframe joints were machined to form sandwiched double-cantilever beam (SDCB) specimens. The SDCB specimens were used to measure the fracture toughness of the EMC/leadframe interfaces under quasi-Mode I loading conditions. After fracture toughness testing, the fracture surface were analyzed by various equipment to investigate failure path. An adhesion model was suggested to explain the failure path formation. The adhesion model is based on the strengthening mechanism of fiber-reinforced composite. The present paper deals with the introduction of the adhesion model. The explanation of the failure path with the proposed adhesion model was introduced in the companion paper.

• 한국표면공학회지
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• 제32권4호
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• pp.531-537
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• 1999

A copper based leadframe was oxidized in brown-oxide forming solution, then the growth characteristics of brown oxide and the effect of brown-oxide formation on the adhesion strength of leadframe to epoxy molding compound (EMC) were studied by using sandwiched double cantilever beam (SDCB) specimens. The brown oxide is composed of fine acicular CuO, and its thickness increased up to ~150 nm within 2 minutes and saturated. Bare leadframe showed alomost no adhesion to EMC, while once the brown-oxide layer formed on the Surface of leadframe, the adhesion strength increased up to ~80 J/$\m^2$ within 2 minutes. Correlation between oxide thickness, $\delta$ and the adhesion strength in terms of interfacial fracture toughness, $G_{c}$ was linear. Considering the above results, we might conclude that the main adhesion mechanism of brown-oxide treated leadframe to EMC is mechanical interlocking, in which fine acicular CuO plays a major role.e.

• 약학회지
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• 제40권2호
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• pp.131-134
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• 1996

3,4-Dimethoxyphenethyl amine(1) and 3,4-dimethoxybenzaldehyde were converted to compounds(4) through sucessive condensation and reduction reaction. Compound(4) was treated with methylthioacetyl chloride to give compound(5) then m-chloroperbenzoic acid(m-CPBA) treatment of compound(5) produced S-oxide(6). To obtain isoquinoline derivative(7),(8), compound(6) were treated with p-TsOH. Xylopinine(9) and it's derivatives(10) were produced by Bischler-Napieralski reaction.

• 한국세라믹학회지
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• 제26권2호
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• pp.267-275
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• 1989

YBa2Cu3O7-x oxide superconductors were fabricated by sintering and hotisostatic pressing (HIP), and their microstructures and properties were compared with each other. Thougha part of the second phase was observed along grain boundaries, their structures were consisted of single (123) phase and they had many porosities. But, porosities were remakably reduced by Hiping and the densification was brought about. The structure of (123) compound also showed a number of twins, which are typical of high Tc superconductors. The on-set temperature of YBa2Cu3O7-x compound sintered at 96$0^{\circ}C$ in oxygen and hipped at 88$0^{\circ}C$ was highest, but that shwoed 0 resistance at 87$^{\circ}$K, which is a little lower than the compound sintered at 96$0^{\circ}C$. HIP treatment also increased the critical current density of as-sintered compound. However, its value was low, which may be ascribed to the many pores of starting-sintered compact and partially to the second phase along grain boundaries.

• 자연과학논문집
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• 제14권2호
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• pp.33-40
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• 2004

유기물이 포함된 황산아연 폐수로부터 황산아연을 회수하기위해서는 유기물의 제거가 필수적이다. 폐수 속에 포함된 유기물을 2차 오염물질이 거의 발생하지 않게 처리하기 위하여 오전 산화법과 흡착법을 병용하여 처리함으로서 효과적으로 유기물을 제거 할 수 있었다. 과량의 황산은 산화아연을 처리하여 황산아연 7수염을 제조함으로써 과량의 황산을 처리할 수 있었다. 폐수 1kg을 처리하여 740g의 황산아연 7수염을 얻었다.

• Current Optics and Photonics
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• 제6권4호
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• pp.359-366
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• 2022

In this paper, we present a new design for angle-sensitive pixels (ASPs). The proposed ASPs take advantage of subwavelength compound gratings to capture the light angle, which enables pixel size to reach the wavelength scale of 0.7 ㎛ × 0.7 ㎛. The subwavelength compound gratings are implemented by the wires of the readout circuit inherent to the standard complementary metal-oxide-semiconductor manufacturing process, thus avoiding additional off-chip optics or post-processing. This technique allows the use of two pixels for horizontal or vertical angle detection, and can determine the light's angle in the range from -45° to +45°. The proposed sensor enables surface-profile reconstruction of microscale samples using a lensless imaging system.

• 한국자기학회지
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• 제14권1호
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• pp.13-17
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• 2004

알루미늄 산화물 절연막에 하프늄의 첨가가 미치는 영향에 관해서 연구하였다. 하프늄을 첨가할 경우 자기저항이 증가하고 자기저항의 온도의존도와 바이어스 전압의존도가 감소함을 관찰하였다. 이는 하프늄의 첨가가 알루미늄 산화물의 결함의 감소를 유발하기 때문이라 판단된다. 하프늄의 첨가된 알루미늄 산화물의 미세구조를 분석한 결과 하프늄이 알루미늄과 혼합됨이 관찰 되었다. 알루미늄과 하프늄의 혼합 금속을 절연막 형성을 위한 금속으로 사용한 결과 하프늄의 첨가된 알루미늄과 동일한 결과를 얻었다. 이로부터 하프늄이 알루미늄과 혼합하면서 절연막 내의 결함을 감소시키고 그에 따른 자기저항의 증가와 자기저항의 온도의존도와 바이어스 전압의존도를 감소시키는 결과를 가져온 것으로 판단된다.

• 한국지반환경공학회 논문집
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• 제4권2호
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• pp.39-46
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• 2003

계면활성제를 이용하여 불포화 지역에 고정화 지역을 설정함으로써, 지하수로 유입되는 유기오염물질의 거동을 지연시킬 수 있다. 본 연구에서는 다양한 수분함량을 보유한 불포화 및 포화 조건에서 연속식 컬럼 실험을 수행함으로써, 수분함량에 따른 계면활성제와 유기오염물질의 거동에 대하여 연구하였다. 산화알루미늄(aluminum oxide)이 충진된 컬럼 실험에서 계면활성제(dialkylated disulfonated diphenyl oxide)의 거동 및 수착 특성은 수분함량이 달라져도 비슷한 결과를 나타내었다. 그러나 계면활성제(DADS)로 개질된 산화알루미늄이 충진된 컬럼 실험에서는 유기오염물질인 나프탈렌(naphthalene)이 수분함량이 감소됨에 따라 거동이 지연되는 현상을 나타내었으며, 또한 더 많은 양의 나프탈렌이 알루미늄 산화물에 흡착된 계면활성제로 흡수되었다. 따라서 본 연구를 통하여 유기오염물질의 고정화 방법이 불포화 지역에도 효과적으로 적용될 수 있음을 알 수 있었다.

• 한국재료학회지
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• 제9권10호
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• pp.992-999
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• 1999

본래 약한 구리계 리드프레임/EMC(Epoxy Molding Compound) 계면의 접착력은 솔더 리플로우 (solder reflow) 공정 중에 종종 박형 플라스틱 패키지의 팝콘 균열 현상(popcorn-cracking phenomena)을 일으킨다. 본 연구에서는 리드프레임/EMC 계면의 접착력을 향상시키기 위하여 리드프레임을 알칼리 용액에 담궈 표면에 brown oxide를 형성시켰으며, EMC로 몰딩(molding)하여 SDCB(Sandwiched Double Cantilever Beam) 시편 및 SBN(Sandwiched Brazil-Nut) 시편을 준비하여 접착력을 측정하였다. 리드프레임의 brown oxide 처리는 미세한 바늘모양의 CuO 결정들을 리드프레임 표면에서 형성시켰으며, 리드프레임/EMC 계면의 접착력을 향상시켰다. 접착력의 향상은 산화층의 평균두께와 직접적인 관련이 있었다. 이는 미세한 바늘모양의 CuO 결정들이 EMC와 기계적인 고착(mechanical interlocking)을 하기 때문으로 생각된다.