• 대한약학회:학술대회논문집
• /
• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
• /
• pp.185.3-185.3
• /
• 2003

Juglone and naphthazarine derivatives were newly systhesized for the evaluation of antifungal activities. These derivatives were prepared by methylation of juglone and 2, 3-dichloro-5, 8-dihydroxy-l, 4-naphthoquinone, and by regioselective nucleophilic subsitution with arylthiols. All compounds were tested in vitro for their growth inhibitory activities against pathogenic fungi by the standard method. The MIC values were determined by comparison to flucytosine as a standard agent. (omitted)

• 한국정보통신학회논문지
• /
• 제15권4호
• /
• pp.860-868
• /
• 2011

블록 암호는 Feistel 구조와 SPN 구조로 나눌 수 있다. Feistel 구조는 암호 및 복호 알고리즘이 같은 구조이고, SPN 구조는 암호 및 복호 알고리즘이 다르다. 본 논문에서는 암호와 복호 과정이 동일한 SPN 구조 블록 암호 알고리즘인 가칭 SSB를 제안한다. SSB는 짝수 N 라운드로 구성하고, 각 라운드는 라운드 키 덧셈, 치환 계층, 바이트 교환 및 확산 계층으로 구성한다. 치환 계층은 홀수 라운드와 짝수 라운드가 서로 역의 관계를 이룬다. 확산 계층은 MDS 대합 행렬로 구성한다. SSB의 차분 및 선형 공격 확률은 $2^{-306}$로 AES와 동일하다. 본 논문에서 제안한 암호와 복호가 동일한 SPN 블럭 암호는 하드웨어 구성이 간단한 장점을 가지므로 제한적 하드웨어 및 소프트웨어 환경인 스마트카드와 전자 칩이 내장된 태그와 같은 RFID 환경에서 안전하고 효율적인 암호 시스템을 구성할 수 있다.

• 대한약학회:학술대회논문집
• /
• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
• /
• pp.350.3-351
• /
• 2002

2-Arylthio-, 2-arylthio-5-methoxy-, 2, 3-bisarylthio-juglones and 2, 3-bisarylthio-5, 8-dimethoxy-1, 4-naphthoquinones were newly systhesized for the evaluation of antifungal activities. These derivatives were prepared by methylation of juglone and 2, 3-dichloro-5, 8-dihydroxy-1, 4-naphthoquinone. and by resioselective nucleophilic subsitution with arylthiols. All compounds were tested in vitro for their growth inhibitory activities against pathogenic fungi by the standard method. The MIC values were determined by comparison to flucytosine as a fungicidal standard agent. In general. In general. most juglone derivatives shows in vitro antifungal activities. Among them. 2-arylthio-5-methoxy-juglones showed most potent antifungal activities against all pathogenic fungi.

• 한국세라믹학회지
• /
• 제43권5호
• /
• pp.284-292
• /
• 2006

$MgTiO_3{\cdot}CaTiO_3{\cdot}SrTiO_3$ system ceramics (MCST) were synthesized to study the effect of Ca addition amount and Sr substitution on temperature coefficient of resonance sequency. Temperature coefficient of resonance frequency was slightly increased by small amount ($i.e.{\sim}5%$) of Sr substitution. In case of 50% to 75% addition amount of $MgTiO_3$, decrease of quality factor was not observed with increasing dielectric constant.

• 복식문화연구
• /
• 제8권5호
• /
• pp.660-667
• /
• 2000

Clothing ventilation was investigated using a manikin wearing an impermeable overall under an isothermal condition, in which the ventilation occurred only through the openings. The ventilation volume was estimated by both microenvironment volume and ventilation rate, where, the microenvironment volume was measured by an air subsitution method and the ventilation rate by a trace gas method. Microenvironment volume of the experimental garment was about 21.0 liters. Even though it was certainly affected by the distance from the opening, the ventilation rate was more significantly influenced by the opening area and the shape of air layer in the clothing. The volume of air exchange in the clothing microenvironment was affected greatly by the microenvironment volume and the opening area, and it was different for each part of the body with bigger air exchange volume in the microenvironment of the leg as compared to that of the arm.

• 한국세라믹학회지
• /
• 제35권10호
• /
• pp.1007-1013
• /
• 1998

The samples of Bi2Sr2Ca1-xNaxCu2O8+y with various carrier concentration were synthesized by substituting Na for Ca ion. The superconducting properties hall coefficients and X-ray powder diffraction were measur-ed the sampled. Single phase samples were obtained for 0$\leq$x<0.3 of Bi2Sr2Ca1-xNaxCu2O8+y In the single phase the critical temperature. {{{{ { T}_{c } }} and carrier concentration increase with the increase of Na concentration pass through a maximum and then decreases. In the range of x$\geq$0.7 to the Na doped samples however we observed the metal-semiconductor transition. The c-axis seemed to decrease and a and b-axes increase with increasing Na concentration in the single phase. Decreasing of c-axis while increasing x is due to the smaller size of {{{{ {Na}^{+1 } }} ions to the {{{{ { Ca}^{+2 } }} ions. In the range of x>0.3 however the trend becomes ambiguous due to the inclusion of the 10K phase and impurity phase.

• 시멘트 심포지엄
• /
• 통권49호
• /
• pp.29-30
• /
• 2022

기후 문제의 심각성이 대두되면서 탄소중립에 세계적인 관심이 커지고 있다. 석회석 미분말은 충전재로써 시멘트 혼합재로 사용할 경우 긍정적인 효과를 얻을 수 있을 것으로 기대된다. 본 연구에서는 석회석 미분말 혼합재의 화학특성이 모르타르 플로우와 압축강도에 미치는 영향을 평가하려고 한다. 결과적으로 모든 석회석 종류와 치환량 수준에서 OPC 수준의 강도보다 저하하는 경향을 나타내었지만 석회석 혼합재를 사용할 경우 유동성이 향상되는 것을 확인하였다. 추후 석회석 시멘트의 단위수량 저감 효과를 이용해 강도 저하를 개선하는 연구를 진행할 계획이다.

• 한국환경성돌연변이발암원학회지
• /
• 제23권1호
• /
• pp.1-6
• /
• 2003

The purpose of this study was to evaluate whether the MTHFR variants, folate and vitamin $B_{12}$ deficiencies increase the risk of hyperhomocysteinaemia and adverse pregnancy outcome such as short gestational age or reduced birth weight. Healthy pregnant women (n=136; 24-28 gestational weeks; 20-40 years old), who visited Ewha Womans University Hospital for prenatal care, participated in this study. At the time of delivery, trained nurses recorded the pregnancy outcome from medical chart. We determined maternal MTHFR polymorphisms (C to T subsitution at nucleotide 677) and measured serum homocyteine, vitamin $B_{12}$, and folate concentrations. We compared serum homocysteine level by MTHFR genotype, serum folate and serum vitamin B12 levels using ANOVA. To evaluate the association between serum homocysteine level and pregnancy outcome, we compared the gestational age and birth weight by serum homocysteine levels using multiple regression analysis, adjusting for other potential predictors. Mean level of serum homocysteine was highest among pregnant women of the MTHFR variants with low levels of serum folate and vitamin $B_{12}$. Regarding association with birth outcome, we found the relationship between homocysteine levels and increased gestational age (p=0.03) and reduced birth outcome (p>0.05). Our data demonstrates that serum level of folate and vitamin $B_{12}$ among pregnant women affects significantly serum homocysteine levels, and the genetic polymorphism of MTHFR modulates the relationship between them. However, we did not have conclusive evidence of association between high homocysteine level and adverse pregnancy outcome such as preterm or low birth weight.

• 한국축산시설환경학회지
• /
• 제5권1호
• /
• pp.53-62
• /
• 1999

This study was carried out to investigate how to reuse the livestock waste and develop fly ash as a subsitution of sawdust which is used commonly to make compost. Fly ash and sawdust were mixed the ratio of 8 to 2, 7 to 3, 6, to 4, 5 to 5, 4 to 6. 3 to 7 and 2 to 8 after fermentation for 60 days the change of temperature, moisture, pH, organic matter, nitrogen content and C/N ratio were analyzed. The results are as follows; Temperature was reached to maximum (63.5$^{\circ}C$) more quickly in scraper type than in slurry type with adding large sawdust. When fly ash and sawdust were mixed same amount at scraper type and slurry type, moisture was 46.6~53.7% and maintained a good condition for fermentation. pH was showed the range of 7~10 as a mixture of fly ash. Organic matter contents were increased with increasing the added sawdust but did not show any tendency. Nitrogen content was also increased with increasing the amount of added sawdust but did not show any tendency. C/N ratio was increased to 20~60 with increasing the added sawdust, but when sawdust and fly ash were mixed 50:50, there was no significant during fermentation periods. In conclusion, supplementation of fly ash at the level of 50% of sawdust maintained a good condition for fermentation as a livestock waste composting.

• 한국자기학회지
• /
• 제5권4호
• /
• pp.281-286
• /
• 1995

Hexaferrite $Ba_{0.25}Sr_{0.75}Fe_{12}O_{19}$에 $SiO_{2}$를 첨가한 쉬트자석의 자기적 성질의 변화를 연구하기 위해 X-선 회절 실험, 뫼스바우어 분광실험, 자기모멘트 측정실험 등을 하였다. 쉬트자석은 Dr. Blade 방법에 의해 제조되었고, 결정구조는 마그네토플럼바이트 M-type 육방결정구조이다. 첨가제 농도에 따른 격자상수의 변화는 거의 없으나, $SiO_{2}$가 2.0 wt.% 이상부터 ${\alpha}-Fe_{2}O_{3}$ 의 상이 나타나기 시작했다. 이성질체 이동값은 Fe이온들이 3가 임을 나타낸다. $SiO_{2}$의 증가에 따라 Curie 온도는 감소함을 보였다. 이것은 $Si^{4+}$가 12k-site $Fe^{3+}$의 자리를 차지함으로써 Fe-O-Fe의 초교환상호작용에 의한 원자간 거리와 양이온 사이의 각이 변함에 따른 것이다. ${\alpha}-Fe_{2}O_{3}$의 상은 $Si^{4+}$가 12k-site $Fe^{3+}$의 자리를 차지함으로 치환된 $Fe^{3+}$에 의해 나타난 것이다. 자기모멘트측정으로 부터 $SiO_{2}$를 첨가한 $Ba_{0.25}Sr_{0.75}Fe_{12}O_{19}$ 쉬트자석은 보자력 $H_{c}$, 포화자화 $M_{s}$, 잔류자화 $M_{r}$이 양이온 치환보다는 미세구조변화에 더 의존함을 알았다.