• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 E
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• pp.1779-1781
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• 1998

We are going to design the Square Pulse Generator use of PCPS (Photo-Conductive Power Switch) for Blumlein lain. The circeuit is made of LC device and it is simulated by Schematics Evaluation Version 8.0 of MicroSim. After charged by DC voltage 15[kV]. When the switch is ON, Square pulse is generated after pause time 1.7857[${\mu}s$]. The square pulse is maximum peak voltage 13.987[kV], pulsed width 3.4017[${\mu}s$], rising time 0.7474[${\mu}s$], falling time 1.1718[${\mu}s$].

• 한국지역지리학회지
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• 제9권4호
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• pp.437-460
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• 2003

통일신라시대의 서원경성의 위치는 청주읍성 지역이 되고 있다. 청주의 매장 문화재인 남석교는 신라 진흥왕 19년 무인년(588년)에 수선했다는 기록으로 보아 남석교의 원조는 그 이전으로 소급될 수 있고 그 후에 수차에 걸쳐 개축되었다는 사실도 알 수 있다. 조선시대 청주읍성의 남북 주축도로는 남문을 통과하고 있고 남문 밖의 시장의 발달로 인하여 남문 밖의 무심천에 위치한 남석교의 역할은 지대할 수밖에 없다. 남석교에서 유래된 대교천의 명칭은 조선 철종 12년(1861년)까지는 대교천으로 불렸고 고종 8년(1871년)에는 무성천으로도 불렸으며 광무 2년(1902년) 이후에는 무심천으로 부르게 되었다고 짐작된다. 청주는 풍수지리와 무심천의 지명유래 등으로 부정적인 이미지를 지니기도 하였지만 점차 긍정적인 이미지로 변화되고 있다. "남석교 사적비"는 1907년까지는 존재하였지만 "표석"과 더불어 유실되었고 "남석교"는 $1931{\sim}1932$년 간의 석교동 제방공사 때문에 매몰되었으며 이러한 문화재들은 가치가 매우 크므로 복원되어야 할 것이다.

• Journal of Ecology and Environment
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• 제29권4호
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• pp.337-342
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• 2006

The total monoterpenoid content of the pine litter layer and the availability of these compounds as inhibitors/stimulators on Polysphondylium violaceum of cellular slime molds were investigated. In order to determine the several monoterpenoids in the natural environment, we examined their concentrations in fresh, senescent, and decaying needles from 3 pine species (Pinus densiflora, P. thunbergii, P. rigida) by litter bag method. Total monoterpenoid content was highest in the fresh needles, but also remained relatively high in senescent needles. The effect of monoterpenoids identified from Pinus plants on the growth of P. violaceum was studied. We tested four concentrations (1, 0.1, 0.01, and $0.001\;{\mu}g/{\mu}L$) of each compound by using a disk volatilization technique. Each compound was treated after germination of spores of P. violaceum. All of the compounds at $1\;{\mu}g/{\mu}L$ concentration had a very strong inhibitory effect on cell growth of P. violaceum. Fenchone at all concentrations, myrcene, verbenone, bornyl acetate, and limonene at low concentrations stimulated the growth of P. violaceum. These results suggest that inhibitory or enhancing effects of selected monoterpenoids depend upon the concentration of the individual compound.

• The Korean Journal of Ecology
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• 제21권5_3호
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• pp.695-702
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• 1998

This study was carried out to investigate to determine seasonal variation of dehydrogenase activity, phosphatase activity, adenosine tri-phosphate content and some physicochemical properties, such as soil pH, moisture content, organic matter and several heavy metal concentrations from Apr. 1997 to jan. 1998 in Pinus densiflora and Quercus mongolica forest in Mt. Nam, to explain a relationship between enzyme activity and the soil factors. There were ranges of 4.03-4.65 in soil pH, 18.65-51.09% in moisture content and 6.69-95.95% in orgainc matter. The organic matter content decreased with soil horizon, showing the higher values in Q. mongolica forest. In comparison to the results of Kawngneung site as control area, there were slightly differences due to a development level of forest ecosystem and microbial degradation of organic matter. The heavy metal concentrations showed 32.50-75.55 ${\mu}g/g$ in Cu, 69.33-134.84 ${\mu}g/g$ in Zn, 57.02-150.32 ${\mu}g/g$ in Pb, and 0.36-1.00 ${\mu}g/g$ in Mt. Nam. These values are higher than in Kwangneung site because of long-term exposure to air pollutants from central city. On the other hand, ATP contents in Mt. Nam were lower than in Kawngneung site in relation to soil organic matter, moisture content and relatively high heavy metal concentrations. ATP contents per soil weight was largest in F+H layer and in spring time of other seasons. Dehydrogenase activity as an index of soil microbial activity had a ranges of 170.67-1,221.66 ${\mu}g$ TPF/g that showed lower values than in Kawngneung site. However, phophatase activity had a contray tendency due to P fertilization for a continuous management. Those values increased through spring to a maximum in the summer and fall in autumn. This is basically caused by metabolic state of soil on the biological activity and several and several factors, such as aeration, soil temperature, vegetation and microflora.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.307-308
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• 2005

ZnO varistor ceramics were fabricated as a function of the sintering temperature from $1125^{\circ}C$ to $1200^{\circ}C$ with glass-frit 0.03wt% addition. The average grain size was increased from 10.4 ${\mu}m$ to 23.7 ${\mu}m$, and varistor voltage was decreased from 538 V to 329 V with rising of the sintering temperature. The nonlinear coefficient a showed similar value from 75 to 80 and leakage current of all specimens exhibited the result of $1{\mu}A$ at 82% of varistor voltage. But the clamping voltage ratio of the specimens sintered at $1175^{\circ}C$ was 1.37 at 25A [$8/20{\mu}s$]. Also, endurance of surge current and deviation of varistor voltage of sintered specimens at $1175^{\circ}C$ were $6400A/cm^2$, $\Delta$-3.32%, respectively.

• 약학회지
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• 제41권1호
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• pp.132-138
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• 1997

The antimicrobial activity of Manuka oil, a steam distillate from Leptospermum scoparium, was investigated, and it's MIC against ten kinds of microorganisms was determin ed. MICs against bacteria and fungi were measured by means of both two-fold dliution method and agar plate two-fold dilution method, respectively. MICs of Manuka oil against Staphylococcus aureus KCTC 1916 and Micrococcus luteus KCTC 1915, gram-positive microrganisms, were identical as 3.05 ${\mu}$g/ml, while it's antibacterial activity against gram-negative microrganisms such as Pseudomonas aeruginosa KCTC 2513, Escherichia coli KCFC 1682, Klebsiella pneunioniae KCTC 2001 or Proteus vulgaris KCTC 2433 was negligible(MIC: ${\geq}$ 1000 ${\mu}$g/ml), suggesting a high susceptibility of gram-positive bacteria to Manuka oil. In addition, MIC against Aspergillus niger KCTC 6077 was 24 ${\mu}$g/ml. and that against the other fungi, Tricophyton mentagrophytes KCTC 1374 and Candida albicans KCTC 1940 was ${\geq}$ 1000 ${\mu}$g/ml. When Manuka oil ointment was used in combination with other drugs. i.e.. gentamycin sulfate, chlotrimazol and hydrocortisone acetate, and diphenhydramine HCl and hydrocortisone acetate. it's antibacterial activity against Staphylococcus aureus KCTC 1916 was higher than Manuka oil ointment or other drugs alone. In conclusion, Manuka oil possesses a selective antibacterial activity against Staphylococcus aureus KCTC 1916, and can be used as a potent antibacterial agent against it.

• Natural Product Sciences
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• 제16권2호
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• pp.68-74
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• 2010

Phytochemical investigation on the ethyl acetate and n-butanol fractions of Moutan Cortex resulted in the isolation and characterization of a new monoterpene glycoside (3) and twenty known monoterpene glycosides (1, 2, 4-21). The structure of 3 was determined by spectroscopic data interpretation and physico-chemical properties. Compounds 1 and 8 presented a remarkable inhibitory activity against lipoxygenase-1 (LOX-1) with $IC_{50}$ values of 45.2 and $37.5\;{\mu}M$, respectively. Compounds 9, 10, 13, 18, 19, and 21 showed significant 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effect with $IC_{50}$ values of 9.8, 25.5, 6.4, 15.2, 18.7, and $23.7\;{\mu}M$, respectively. Benzoylpaeoniflorin (8), which exhibited the highest inhibitory effect with an $IC_{50}$ value of $37.5{\pm}0.7{\mu}M$, was further analyzed the inhibition kinetics by Lineweaver-Burk plots. Results indicated that 8 is a non-competitive inhibitor, and the kinetic parameter values were estimated to be ($31.04\;{\mu}M$, Ki), ($0.29\;{\mu}M/min$, $V_m$), and ($48.50\;{\mu}M$, $K_m$).

• 한국보건교육건강증진학회:학술대회논문집
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• 한국보건교육건강증진학회 2007년도 춘계학술대회 자료집
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• pp.95-97
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• 2007

• 과학과기술
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• 제25권3호통권274호
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• pp.38-39
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• 1992

• 대학교육
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• 통권10호
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• pp.81-86
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• 1984