• Bulletin of the Korean Chemical Society
• /
• 제7권5호
• /
• pp.367-371
• /
• 1986

Dynamic and equilibrium properties of n-alkane chains immersed in solvent molecules have been investigated by a molecular dynamics method. The n-alkane chain is assumed to be a chain of elements (CH$_2$) interconnected by bonds having a fixed bond length and bond angle, but each bond of the chain is allowed to execute hindered internal rotation. We studied the effect of the number of the chain elements (N$_c$ = 10, 15 and 20) on the equilibrium properties of the system, e.g., the pair correlation functions between a chain element and solvent molecules, g$_{cs}$(r), and between the chain elements, g$_{cc}$(r), and the configurational properties such as the mean-square end-to-end distance < R$^2$ >, the mean-square radius of gyration < S$^2$ >, and the eigenvalues of the moment-of-inertia tensor < S$_i^2$ > / < S$^2$ > (i = 1, 2 and 3). We also studied the dynamic properties of the system, e.g., the autocorrelation function C(A;t) where A = R$^2$(t), = S$^2$(t), or = ${\vec{V}}(t)({\vec{V}}$ = velocity of the center of mass), and the diffusion coefficient D. The g$_{cs}$(r)'s are almost equal irrespective of the change of Nc while g$_{cc}$(r) becomes larger as N$_c$ increases; The MD computed configurational properties < R$^2$2 > and < S$^2$ > were found to be a little different from the values calculated from the statistical equations of < R$^2$ > and < S$^2$ >, it may be due to the fact that our model for the MD simulations includes a long-range volume effect. From the < S$_i^2$ > / < S$^2$ >, it is found that the chain molecule has a nearly spherical shape irrespective of the variation of N$_c$. For the dynamic properties we found that the C(R$^2$;t) and C(S$^2$;t) of lower N$_c$ decay faster than those of higher N$_c$, while the C($\vec V$;t) of the center of mass in the chain is weakly dependent on the N$_c$. The center of mass diffusion coefficient D$_c$ decreases as N$_c$ increases while the end point diffusion coefficient D$_e$ is nearly equal irrespective of the change of N$_c$.

• 한국자기학회:학술대회 개요집
• /
• 한국자기학회 2006년도 동계학술연구발표회 및 자성 스핀트로닉스 국제학술대회
• /
• pp.21-21
• /
• 2006

• 한국자기학회:학술대회 개요집
• /
• 한국자기학회 2006년도 동계학술연구발표회 및 자성 스핀트로닉스 국제학술대회
• /
• pp.20-20
• /
• 2006

• 고려인삼학회:학술대회논문집
• /
• 고려인삼학회 2002년도 학술대회지
• /
• pp.491-501
• /
• 2002

A cross-examination between KT&G Central Research Institute and Guangzhou Institute for Drug Control was carried out in order to select optimum conditions for extraction, separation and determination of ginsenosides in red ginseng and to propose a better method for the quantitative analysis of ginsenosides. The optimum extraction conditions of ginsenosides from red ginseng were as follows: the extraction solvent, $70\%$ methanol; the extraction temperature, $100^{\circ}C;$ the extraction time, 1 hour for once; and the repetition of extraction, twice. The optimum separation conditions of ginsenosides on the SepPak $C_{18}$ cartridge were as follows: the loaded amount, 0.4 g of methanol extract; the washing solvents, distilled water of 25 ml at first and then $30\%$ methanol of 25 ml; the elution solvent, $90\%$ methanol of 5 ml. The optimum HPLC conditions for the determination of ginsenosides were as follows: column, Lichrosorb $NH_2(25{\times}0.4cm,$ 5${\mu}m$, Merck Co.); mobile phase, a mixture of acetonitrile/water/isopropanol (80/5/15) and acetonitrile/water/isopropanol (80/20/15) with gradient system; and the detector, ELSD. On the basis of the optimum conditions a method for the quantitative analysis of ginsenosides were proposed and another cross-examination was carried out for the validation of the selected analytical method conditions. The coefficient of variances (CVs) on the contents of ginsenoside-$Rg_{1}$, -Re and $-Rb_1$ were lower than $3\%$ and the recovery rates of ginsenosides were $89.4\~95.7\%,$ which suggests that the above extraction and separation conditions may be reproducible and reasonable. For the selected HPLC/ELSD conditions, the CVs on the detector responses of ginsenoside-Rg, -Re and $-Rb_1$) were also lower than $3\%$, the regression coefficients for the calibration curves of ginsenosides were higher than 0.99 and two adjacent ginsenoside peaks were well separated, which suggests that the above HPLC/ELSD conditions may be good enough for the determination of ginsenosides.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2010년도 춘계학술대회 논문집
• /
• pp.1031-1032
• /
• 2010

• 한국수정란이식학회:학술대회논문집
• /
• 한국수정란이식학회 2003년도 제3회 발생공학 국제심포지움 및 학술대회
• /
• pp.110-110
• /
• 2003

• 한국식물병리학회지
• /
• 제3권2호
• /
• pp.85-92
• /
• 1987

본 실험은 전기영동법에 의하여 탄저병균의 종분류를 하였다. 고추 탄저병균인 Colletotrichium gloeosporioides, C. dematium과 사과 탄저병균 Gloeosporium fructigenum은 esterase, leucine aminopeptidase, acid phosphatase와 glutamic oxaloacetic transaminase 동위효소에 의해 구분되었다. 특히 C. gloesoporioides의 G와 R-strain이 효소 pattern에 의해 구분되었다. G-strain은 고추의 모든 열매(푸른고추, 붉은고추)를 침해하나, R-strain은 단지 붉은 고추를 침해하고 푸른고추는 침해하지 않는다

• 한국식품과학회지
• /
• 제30권4호
• /
• pp.862-870
• /
• 1998

Myosin과 그 subfragment인 S-1과 LMM를 항원으로 하는 간접경합 효소면역분석법(Ci-ELISA)을 이용하여 동결육의 변화를 연구함으로써 수입 냉동육과 국내산 냉장 한우육과의 차별화를 위한 기초 자료를 마련하기 위하여 본 연구를 실시하였다. 각 항체의 표준곡선을 작성하였으며 최적반응범위는 $4{\sim}125{\;}{\mu}g/mL$이었고, 검출한계는 $0.1{\;}{\mu}g/mL$이었다. 확립된 Ci-ELISA를 이용하여 각각 $-10^{\circ}C,{\;}-20^{\circ}C,{\;}-50^{\circ}C$, 그리고 $-80^{\circ}C$에서 동결 기간 동안의 변화와 해동과 재동결에 따른 변화를 측정하였을 때 동결 기간 중 anti-MWM IgG와 반응한 myosin은 비교구와 비교하였을 때 $-20^{\circ}C$에서 변성도가 가장 컸으며 $-50^{\circ}C$에서 가장 적게 변성되었다. 단백질 용해성의 변화와 myosin과 항체와의 면역 친화성을 비교하였을 때 용해성이 감소하는 속도보다 더 빠르게 myosin이 변성되는 것으로 판단되었다. Anti S-1 IgG의 면역 친화성의 변화는 anti-MWM IgG에서 얻은 결과와 비교하였을 때 전혀 다른 경향을 보였다. anti-MWM IgG는 면역 친화성이 1개월 이후 급격히 감소된 데 비하여 anti S-1 IgG는 그와 같은 큰 변화를 나타내지 않았다. 반복되는 해동과 재동결 처리에서 anti-MWM IgG는 myosin과의 반응에서 2회 해동시부터 공격한 반응성의 감소를 보였으며 6회 해동시에는 85%까지 반응력을 상실했다(P<0.05). 두 실험 조건에서 $-20^{\circ}C$의 처리구의 myosin이 가장 심한 영향을 받은 것으로 나타났다. Anti-LMM IgG는 anti-MWM IgG에서 얻은 결과와 매우 유사한 경향을 보였다. $-10^{\circ}C$와 $-20^{\circ}C$에서 처리된 우육의 myosin은 저온에서 처리된 시료의 그것보다 보다 약 $10{\sim}15%$ 정도 더 많은 변성을 보인 것으로 사료된다.

• 대한화장품학회:학술대회논문집
• /
• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book II
• /
• pp.527-527
• /
• 2003

A high-performance liquid chromatographic method for the simultaneous quantitative analysis of DMDM hydantoin, sorbic acid, phenoxy ethanol in cosmetics was studied by using a X-terra C$\sub$18/ column and 0.75mM KH$_2$PO$_4$ in 0.85% sulfuric acid and methanol mixture(7:3) at 214nm. Calibration curves were found to be linear in the 20-100 $\mu\textrm{g}$/mL range (DMDM hydantoin), 50-250 $\mu\textrm{g}$/mL range (sorbic acid) and 10-50 $\mu\textrm{g}$/mL range (phenoxy ethanol). The result of recovery test were 96.6% ∼ 104.2%. This HPLC method can be applied quality control of cosmetics.

• 한국농공학회논문집
• /
• 제63권4호
• /
• pp.87-96
• /
• 2021

Determining design rainfall is the first step to plan an agricultural drainage facility. The objective of this study is to evaluate whether the current method for parameter estimation is reasonable for computing the design rainfall. The current Gumbel-Kendall (G-K) method was compared with two other methods which are Gumbel-Chow (G-C) method and Probability weighted moment (PWM). Hourly rainfall data were acquired from the 60 ASOS (Automated Synoptic Observing System) stations across the nation. For the goodness-of-fit test, this study used chi-squared (𝛘²) and Kolmogorov-Smirnov (K-S) test. When using G-K method, 𝛘² statistics of 18 stations exceeded the critical value (𝑥²_a=0.05,df=4=9.4877) and 10, 3 stations for G-C method, PWM method respectively. For K-S test, none of the stations exceeded the critical value (D^a=0.05_n=0.19838). However, G-K method showed the worst performances in both tests compared to other methods. Subsequently, this study computed design rainfall of 48-hour duration in 60 ASOS stations. G-K method showed 5.6 and 6.4% higher average design rainfall and 15.2 and 24.6% higher variance compared to G-C and PWM methods. In short, G-K showed the worst performance in goodness-of-fit tests and showed higher design rainfall with the least robustness. Likewise, considering the basic assumptions of the design rainfall estimation, G-K is not an appropriate method for the practical use. This study can be referenced and helpful when revising the agricultural drainage standards.