• Korean Journal of Optics and Photonics
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• v.8 no.3
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• pp.213-217
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• 1997

We have measured photoluminescence (PL) and time-resolved PL in doped-GaAs. As increasing doping concentration, the PL spectra of n-type GaAs shift to higher energies while the PL spectra of p-type GaAs shift to lower energies than the bandgap of the undoped GaAs. The contribution of the Burstein-Moss effect overrules the band-gap narrowing in n-type GaAs, contrary to p-type GaAs. The PL rise time and decay time become shorter as increasing doping concentration. The PL rise and decay time in doped-GaAs depend on the type of majority carriers and their concentrations, which imply that the carrier-carrier interaction plays an important role in the energy relaxation processes.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.42-42
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• 1993

Angiotensin converting enzyme (ACE)은 혈압 상승작용과 밀접한 관계가 있는 효소이다. 따라서 이 효소의 작용 억제는 혈압 강하를 초래한다. 본 실험에서는 ACE와 여러점에서 유사점을 가진 Carboxypeptidase A에 대하여 강력한 억제 효과를 나타내는 간단한 구조의 억제제를 개발한 바 있는데. 이때 사용한 억제제 설계방법을 ACE 억제제 개발에 적용시켜 ACE 억제를 통한 고혈압 강하제 개발을 목적으로 하였다. ACE 억제작용에 있어서의 알려진 구조-활성 상관 관계와 ACE의 활성부위를 기초로 해서 아래와 같은 구조의 물질을 억제작용 보유의 물질로 설계하고 합성하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.5
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• pp.798-805
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• 1986

단열 혹은 등온 경계조건 하의 수직평판과, 선열원으로부터 형성되는 열상승류 간의 열적 상호작용을 조사형ㅆ다. 경계층 방정식은 Patankar-Spalding의 유한차분법을 사용하여 계산하였다. 단열평판의 경우에 자유 열상승류로부터 벽 경계층으로 부터의 점진적인 발달 단계를 설명하였다. 등온평판의 경우에는 평판주위에 새롭게 형성되는 열경계층에서의 열전달현상을 자세히 고찰하였다.

• Korean Journal of Environmental Biology
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• v.23 no.1
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• pp.64-70
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• 2005

To investigate the synergistic effects of low dose gamma irradiation and growth regulators on the growth and photosynthesis in rice (Oryza sativa L.), laboratory and greenhouse experiments were conducted using 4-year-old rice seeds. In the laboratory experiment, the germination rate was increased in 0.001 ppm IBA treatment, showing the synergistic effect of gamma irradiation and growth regulators. The seedling growth was increased by treatment of GA₃ and IBA, the irradiated groups having higher than the non-irradiated ones. Particularly, it was remarkable in 0.001 ppm IBA. In greenhouse experiment, seedling growth was increased in response to a combination of gamma irradiation and 0.001 ppm IBA. Effective quantum yield of PSⅡ(Ф/sub PSⅡ/) and photochemical quenching (qP) were increased, while non-photochemical quenching (qN) was decreased by 0.001 ppm IBA. A synergistic effect of gamma irradiation and IBA was only found in seedling growth. The present results suggest that low dose gamma irradiation and growth regulator could synergistically stimulate seedling growth.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.6
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• pp.686-692
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• 1992

The present study was carried out to examine the antioxidative actions between the products of amino-carbonyl reaction and commercial antioxidants, and investigate their synergistic effects. Nondialyzable melanoidins exhibited more significantly in the antioxidative action than unfractionated meanoidins did. Also, in the case of unfractionated melanoidins, both glycine and histidine were more effective than aspartic acid for the antioxidative action. There was no significant difference among amino acids in the action of nondialyzable melanoidins. The unfractionated melanoidin was not as good as antioxidative action of the synthetic antioxidants, butylated hydroxytoluene, tert-butyl hydroquinone and ascorbic acid ; however, the one was superior to that of natural antioxidants, ${\alpha}$-tocopherol and lecithin. Otherwise, the action of nondialyzable melanoidin was similar to that of synthetic antioxidant. The synergistic effects were increased in using melanoidin with ${\alpha}$-tocopherol and lecithin except for the systems of fructose-aspartic acid and fructose-glycine in unfractionated melanoidins.

• Weed & Turfgrass Science
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• v.5 no.3
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• pp.136-143
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• 2016

This study was conducted to investigate the algicidal characteristics of cashew nut oil (CNO) and to develop CNO mixtures with other compounds having synergistic effects on the growth inhibition against a blue-green alga, Microcystis aeruginosa. Among tested CNOs, CNO with higher anacardic acid contents (Ana-A) exhibited the best algicidal activity against M. aeruginosa. Ana-A showed broad algicidal spectrum with particular greater activity against blue-green algae than green algae. Ana-A showed the greatest activity against to Oscillatoria tenuis ($IC_{50}=0.19{\mu}g\;mL^{-1}$) among the tested blue-green algae and to Chlorella vulgaris ($IC_{50}=4.54{\mu}g\;mL^{-1}$) among the tested green algae, respectively. In a mixture experiment to evaluate a chemical interaction in M. aeruginosa control, Ana-A showed a strong synergistic effect with MSB and menadione, mild synergistic effect with citric acid, and additive effect with chryspophanol, copper sulfate and quinoclamine. Taken together, our results suggest that CNO containing higher anacardic acid can be used as an eco-friendly natural algicide for selective control of blue-green algae such as M. aeruginosa and O. tenuis through an optimization of application rate and in combination with synergists such as MSB and menadione.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2002.05a
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• pp.227-230
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• 2002

환경문제를 야기하는 할론 소화설비의 사용이 금지되면서 대체소화설비로 관심을 끌며 연구되기 시작한 미세물분무 소화설비이다. 미세물분무는 고압에서 물을 방사하여 $Dv_{0.99}$가 1,000$\mu$m 미만의 물입자를 만들며 작은 물입자로 인해 표면적의 증가와 증발특성이 우수하고, 산소농도를 감소시키는 질식작용과 화염의 냉각작용에 의해 소화작용을 상승시킨다. 이러한 미세물분무의 소화작용에 대한 소규모 화재실험을 기반으로 유류화재의 진압$\cdot$소화특성에 대한 실용화를 위해 실제크기 화재실험을 하였다.(중략)

• Journal of the Speleological Society of Korea
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• no.48
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• pp.9-16
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• 1996

석회동굴은 유구한 지구 표면 지층의 역사를 되새겨 주는 석회암 층에서 형성되는 지하동굴이다. 바다 속에서 퇴적되어 형성된 석회암 층이 융기 작용으로 지표면에 상승되어 이른 바 석회암 지표 층을 이루고 있는 곳에서는 빗물에 의한 화학작용으로 땅 표면에서 카르스트 윤회과정의 갖가지 지형지물이 발달되는데, 이 때에 지하에 스며든 지하수의 물리 작용으로 곧 지하수류가 흘러 지나간 공동이 생기게 되고, 나아가서는 낙반 및 확장 등으로 지하동굴이 확장되는데, 2차적인 지하수 침투작용으로 석회질 용해수에 의한 2차 생성물이 형성되어 이른 바 화려한 석회동굴이 이루어진다. 그 석회암의 화학 성분 여하에 따라, 그리고 지하수의 지하 투수량에 따라 석회동굴의 양상은 달리 나타나게 된다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.842-849
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• 1997

This study was designed to investigate the antioxidative activity of enzymatic hydrolysates prepared from defatted anchor muscle by various pretenses. In these hydrolysates, the hydrolysates derived from pepsin and Protamex showed the strongest antioxidative activity. Enzymatic hydrolysates also showed the synergistic effects on antioxidative activity of $\alpha-tocopherol$, and almost no change in butylated hydroxytoluene (BHT). Peroxidation of metal ions $(Fe^{3+},\;Cu^{2+})$ was inhibited by enzymatic hydrolysates. Ten fractions (P-1 to P-10) were fractionated from the peptic hydrolysates by Amberlite IR-120 and Bio-gel P-2 column chromatography. The maximum antioxidative activity was observed in the traction P-2 (fraction No. $26\~31$). In amino acid composition of before and after hydrolysis of defatted anchovy muscle and the active fractions (P-2), contents of aspartic arid and glutamic acid were increased, but alanine, cysteine, tyrosine and phenylalanine were decreased.

• The Korean Journal of Pharmacology
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• v.27 no.1
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• pp.21-31
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• 1991

When administered intracerebroventricularly (icv), cholinergic nicotinic agents, nicotine and DMPP, as well as cholinergic muscarinic agents, muscarine and bethanechol, produced pressor responses in urethane-anesthetized vagotomized rabbits. The response patterns to nicotine and to DMPP were similar, while the bethanechol response resembled the muscarine pattern. The pressor response to nicotine and DMPP was markedly inhibited by icv mecamylamine but not by icv pirenzepine, whereas the response to muscarine and bethanechol was inhibited by icv pirenzepine but not by icv mecamylamine, suggesting that both nicotinic and muscarinic receptors in the brain are involved in the action. Intravenous pretreatments of animals with regitine, reserpine, enalapril, saralasin, both regitine and enalapril, both regitine and saralasin, SK&F-100273 did not prevent the pressor response to nicotine and muscarine. Iv pretreatments with both regitine and SK&F-100273 inhibited the nicotine response without affecting the muscarine response, whereas pretreatments with three agents, regitine, enalapril and SK&F-100273, inhibited the muscarine response. The nicotine-induced elevated blood pressure as well as the muscarine-induced were lowered by regitine but not by enalapril or by SK&F-100273. Enalapril was without effect on the nicotine hypertension in rabbits treated with regitine or both regitine and SK&F-100273, whereas SK&F-100273 lowered the nicotine hypertension in regitine-treated animals. Enalapril did not enhance the lowering effect of SK&F-100273 in regitine-treated ones, nor did it cause a fall of the muscarine hypertension induced in regitine-treated rabbits, but it did lower the blood pressure in animals treated with both regitine and SK&F-100273. Likewise, SK&F-100273 did not cause a fall of the muscarine hypertension induced in regitine-treated rabbits, but it did lower the blood pressure in animals treated with both regitine and enalapril. These data suggest that the nicotine-induced hypertensive state is related to at least two systems in the periphery-sympathetic and vasopressin, whereas in the muscarine-induced hypertensive state three systems in the periphery are involved, i.e., the sympathetic, vasopressin and angiotensin system. The hypotensive effect of regitine on basal arterial blood pressure levels of rabbits was not influenced by pretreatment with either of enalapril or SK&F-100273, but significantly potentiated by treating with both enalapril and SK&F-100273, suggesting participation of the sympathetic and the renin-angiotensin system as well as the vasopressin system in maintenance of arterial blood pressure.