• KSBB Journal
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• 제15권5호
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• pp.452-457
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• 2000

Buffer의 특성에 맞는 체류인자에 관한 모텔식을 얻기 위 해서는 buffer 9} 양이온의 농도에 관한 관련식을 실험으로 결 정해야 한다 또한 model 식에서 비이온과 음이온의 체류인 자를 나타내는 ko와 k의 값이 일정한 경향을 나타내고 있기 때문에 buffer의 농도와 modifier의 농도를 동시에 고려한 model 식이 가능하게 된다. 본 연구에서 제안한 모델식을 이용하여 임의의 buffer의 농도에 따른 시료의 체류시간을 예측할 수 있다. 이러한 모텔식을 이용하여 buffer를 이 용한 RP-HPLC의 분석 및 분리조건을 예측할 수 있고 시행 오차적인 방법보다 빠른 시간 내에 최적의 분석 및 분리조건 을 얻을 수 있다

• Bulletin of the Korean Chemical Society
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• 제27권2호
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• pp.211-218
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• 2006

This work deals with 24 substances composed of nitrogen-containing heterocycles. The relationships between the chromatographic retention factor (k) and those physicochemical properties which are relevant in quantitative structure-properties relationship (QSPR) studies, such as the polarizability $(\alpha)$, molar refractivity (MR), lipophilicity (logP), dipole moment $(\mu)$, total energy $(E_{tot})$, heat of formation $(\Delta H_f)$, molecular surface area $(S_M)$, and binding energy $(E_b)$, were investigated. The accuracy of the simple linear regressions between the chromatographic retention and the descriptors for all of the compounds was satisfactory (correlation coefficient, $0.8 \leq r \leq 1.0$). The QSPR models of these nitrogen-containing heterocyclic compounds could be predicted with a multiple linear regression equation having the statistical index, r = 1.000. This work demonstrated the successful application of the multiple linear approaches through the development of accurate predictive equations for retention factors in liquid chromatography.

• Bulletin of the Korean Chemical Society
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• 제24권12호
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• pp.1757-1762
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• 2003

The interrelation between retention factors of several L-amino acids and their physico-chemical and structural properties can be determined in chromatographic research. In this paper we describe a predictor for retention factors with various properties of the L-amino acids. Eighteen L-amino acids are included in this study, and retention factors are measured experimentally by RP-HPLC. Binding energy ($E_b$), hydrophobicity (log P), molecular refractivity (MR), polarizability (${\alpha}$), total energy ($E_t$), water solubility (log S), connectivity index (${\chi}$) of different orders and Wiener index (w) are theoretically calculated. Relationships between these properties and retention factors are established, and their predictive and interpretive ability are evaluated. The equation of the relationship between retention factors and various descriptors of L-amino acids is suggested as linear and multiple linear form, and the correlation coefficients estimated are relatively higher than 0.90.

• 한국조리학회지
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• 제12권4호
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• pp.18-32
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• 2006

This research is to figure out how interpersonal relationships among the foodservice industry affected customer satisfaction and retention. Marketing strategy methods could be indicated to bear fruit in the food-industry based on this research. First, the properties of each factor related interpersonal relationship of foodservice industry, customer satisfaction and retention were obtained from previous studies. Second, interpersonal relationship was applied as an independent variable, retention between customers and the foodservice industry as a consequent variable and customer satisfaction as a parameters. The result reached through convergent validity came to satisfy all variables. Third, it was strongly maintained that the higher interpersonal relationship was, the more satisfied customers were and that the more satisfied customers were, the stronger retention was. It was shown that customers would repurchase and had strong loyalty to a certain enterprise if its services satisfied them and met their expectations.

• 한국조리학회지
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• 제14권2호
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• pp.99-114
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• 2008

The purpose of this study is to examine the relationships between each type of attitudes toward money and the attributes of choosing family restaurants. A self-administrated questionnaire was completed by 387 students, and data were analysed by frequency, factor, reliability and canonical correlation. Seven factors were obtained from factor analysis of attitudes toward money; Factor 1 "power", Factor 2 "obsession", Factor 3 "retention", Factor 4 "achievement", Factor 5 "anxiety", Factor 6 "distrust", and Factor7 "evaluation". The attributes of family restaurant choice were extracted into six factors: Factor 1 "quality of food", Factor 2 "restaurant event", Factor 3 "interior environment", Factor 4 "value of food", Factor 5 "convenience for approach", and Factor 6 "employees' service". Canonical correlation analysis showed three significant functions. Canonical function 1 showed that the attitudes of considering the power of money, its retention and achievement were indicated to have significantly positive relationships with the quality of food in the attributes of choosing family restaurants. Canonical function 2 showed that significantly negative relationships between distrust and restaurant events and convenience for approach. Canonical function 3 also showed that significantly positive relationships between obsession and anxiety and the interior of restaurants and employees' service, and significantly negative relationships between evaluation and the interior of restaurants and employees' service.

• KSBB Journal
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• 제19권4호
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• pp.263-268
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• 2004

최근 생체 내에서 다른 약리활성을 보이는 키랄물질의 고순도 제조에 관심이 증가되고 있다. 현재 널리 사용되고 있는 것은 키랄고정상을 이용한 기존 분리방법에 비해서, 제조 후 안정성과 환경적인 측면을 고려한 초임계유체를 이용한 분리방을 시도하였다. 본 연구에서는 키랄물질인 ibuprofen의 최적의 분리 조건을 구하기 위해서 온도와 압력, 첨가되는 IPA의 양에 따른 체류인자와 분리도의 영향을 고찰하였다. 온도가 감소하고 압력이 증가할수록 체류인자는 감소하였다. IPA의 양에 따라 더 큰 영향을 받아서 IPA의 양이 많을수록 분리도는 감소하는 경향을 보였다. 실험으로부터 정한 최적의 분리조건은 130 bar, 311.15 K, 4% IPA (vol.)일 때이었다. 동일한 주입량에서 액체 크로마토그래피에서는 비선형의 용출곡선을 보였지만, 초임계유체 크로마토그래피에서는 선형의 용출곡선을 얻었다.

• KSBB Journal
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• 제20권4호
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• pp.260-265
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• 2005

N-CBZ-L-phenylalanine를 주형분자로 하고 MAA와 4-VPY를 기능성 단량체로 하여 분자각인 고분자를 합성하였다. N-CBZ-L-phenylalanine와 MAA, 4-VPY는 수소결합의 영향을 많이 받고 있으며 이온결합과 소수성결합도 작용하고 있다. 혼합성분을 기능성 단량체로 사용함으로 하여 단량체의 성분들 사이에서 상호작용 효과를 나타냈다. 실험결과에 의하면 혼합 성분인 MAA와 4-VPY를 기능성 단량체로 한 분자각인 고분자에서의 체류인자가 단일성분인 MAA를 사용한 고분자에서의 체류인자보다 컸고 컬럼 효율은 낮았지만 분리도는 높았다. 산성인 MAA와 염기성인 4-VPY를 함께 사용함으로써 거울상 이성질체인 N-CBZ-L-phenylalanine과 N-CBZ-D- phenylalanine의 분리도를 증가시킬 수 있었다. 혼합된 성분의 기능성 단량체로하여 제조된 분자각인 고분자를 키랄 물질의 분리를 비롯한 천연물질의 분리에 더 광범위하게 사용될 수 있을 것이다.

• 한국농공학회지
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• 제32권E호
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• pp.47-58
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• 1990

Abstract A regionalized daily streamflow model using a modified retention parameter in the SCS method was developed to predict the daily streamflow of a natural series for Korean watersheds. Model verification showed that it is possible to use the model for extending short period records in a gaged watershed or for predicting daily streamflow in any ungaged watershed, with reasonable accuracy by simply inputing the name of the watershed boundary, the watershed size, the latitude and longitude of the watershed, and the daily areal rainfall.

• 한국축산식품학회지
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• 제30권6호
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• pp.1024-1030
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• 2010

굽기에 비해 삶기를 했을 경우 중량과 부피의 감소가 큰 것으로 나타났다. 부위별로 조금씩의 차이를 보이기는 하지만 지방은 조리 후에 증가하는 것으로 조사 되었으며 수분과 단백질은 감소하는 것으로 조사되었다. 무기질함량은 굽기를 했을 때 증가하는 경향을 보였으며, 삶기를 했을 때 감소하는 경향을 보였다. 영양소 잔존율는 굽기에서 삶기에 비하여 높게 나타나는 경향을 보이는 것으로 조사되었고, 수분, Na, K, P에서 유의적인 차이를 보였다(p<0.05). 잔존율 변화는 기존 분석자료와 비교했을 때 조리후의 영양소가 오히려 증가하는 것처럼 보이나 잔존량계수 계산법을 사용하게 되면 영양소가 감소하거나 증가 폭이 줄어드는 것으로 나타났다. 전국적으로 유통되는 한우는 더 다양하며, 등급 품질 역시 5등급으로 구성되어 한우의 일부 특성만을 보여주고 있다는 한계점을 지니고 있다. 따라서 추후 국내에 유통되는 다양한 브랜드 한우를 이용한 연구가 이루어져야 할 것이다.

• Bulletin of the Korean Chemical Society
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• 제24권9호
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• pp.1265-1268
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• 2003

The estimation of retention factors by correlation equations with physico-chmical properties maybe helpful in chromatographic work. The physico-chemical properties were water solubility (S), hydrophobicity (P), total energy ($E_t$), connectivity index 1 ($^1{\chi}$), hydrophilic-lipophlic balance (x) and hydrophilic surface area (h) of isoflavones. The retention factors were experimentally measured by RP-HPLC. Especially, the empirical regulations of water solubility and hydrophobicity were expressed in a linear form. The equation between retention factors and various physico-chemical properties of isoflavones was suggested as $k = a_0 + a_1\;log S + a_2log\;P^Q + a_3(E_t) + a_4(^1{\chi}) + a_5(x) + a_6(h)$, and the correlation coefficients estimated were relatively higher than 0.95. The empirical equations might be successfully used for a prediction of the various chromatographic characteristics of substances, with a similar chemical structure.