• Bulletin of the Korean Chemical Society
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• v.18 no.5
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• pp.478-484
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• 1997

In a recent paper[Bull. Kor. Chem. Soc. 17, 735 (1996)] we reported results of molecular dynamic (MD) simulations for the thermodynamic and structural properties of liquid n-alkanes, from n-butane to n-heptadecane, using three different models. Two of the three classes of models are collapsed atomic models while the third class is an atomistically detailed model. In the present paper we present results of MD simulations for the dynamic properties of liquid n-alkanes using the same models. The agreement of two self-diffusion coefficients of liquid n-alkanes calculated from the mean square displacements (MSD) via the Einstein equation and the velocity auto-correlation (VAC) functions via the Green-Kubo relation is excellent. The viscosities of n-butane to n-nonane calculated from the stress auto-correlation (SAC) functions and the thermal conductivities of n-pentane to n-decane calculated from the heat-flux auto-correlation (HFAC) functions via the Green-Kubo relations are smaller than the experimental values by approximately a factor of 2 and 4, respectively.

• Bulletin of the Korean Chemical Society
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• v.17 no.7
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• pp.653-655
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• 1996

A comparative molecular field analysis (CoMFA) was carried out for the correlation of the transition state structures and the reaction rates for the SN2 reaction of 4-nitrophenyl benzoate and its sulfur analogs with anionic nucleophiles. The CoMFA analysis showed that both steric and electrostatic effects are important, and the steric contribution increased when nucleophiles are alkoxides or arylsulfides. In this study, we have demonstrated that the CoMFA analysis can be expanded beyond the scope of dealing with reactants and products. The reactant complex and transition state conformations generated along the reaction path can be more appropriately used for the correlation of structures and reaction rates.

• Bulletin of the Korean Chemical Society
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• v.9 no.3
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• pp.179-182
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• 1988

A simple correlation between cross interaction constants ${\rho}_{ij}$ and bond lengths in the transition state was obtained ; it has been shown that ${\rho}_{ij}$ corresponds to force constant of activation, which in turn is related to bond length by Badger's rule involving only universal constants. A satisfactory correlation between 4-31G ab initio calculated values of bond length and force constant for C-X streching in the transition state of the methyl transfer reaction, $X^-\;+\;CH_3X\;=\;XCH_3\;+\;X^-$, indicated that Badger's rule can be extended to bonds in the transition state. Independence of ${\rho}_{ij}$ values from the variable charge transmission of reaction centers has been demonstrated with nearly constant, experimentally determined I${\rho}$XYI values, and hence similar degree of bond formation, for various $S_N2$ reactions.

• 한국연소학회:학술대회논문집
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• 2002.06a
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• pp.163-170
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• 2002

The main objective of this study is to investigate the correlation of chemical structure and cetane number of reformed diesel fuels by ultrasonic irradiation. In order to analyze the effect of the chemical structure and the cetane number of reformed diesel fuels by ultrasonic irradiation, $^1H-NMR$ was used. From the study, following conclusive remarks can be made. 1) BI(=Branch Index), aromatics percentages, and $H_{\alpha}(={\alpha}-methyl$ functional group) of the reformed diesel fuels by ultrasonic irradiation decreased more than those of the conventional diesel fuel. 2) All the cetane numbers which were calculated from carbon type structure and hydrogen type distribution of the reformed diesel fuels increased more than those of the conventional diesel fuel. 3) Using predicated equation of cetane number caculated from carbon type structure is more reasonable than that caculated from hydrogen type distribution 4) BI, aromatics percentages, and $H_{\alpha}$ on both of conventional fuel and reformed diesel fuels by ultrasonic irradiation are inversely proportional to cetane number on these fuels.

• Korean Journal of Plant Resources
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• v.7 no.2
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• pp.109-114
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• 1994

Followings are resulted through the analysis of the maln characters and the leaf ingredients, which is on the purpose of getting the basic materials to improve jaso and increase its production.Of the introduced varieties, Jukyeubjaso-stem length is 180cm, ear length is 37cm, No. of branches ofstem is 27, leaf length Is 16cm, leaf width Is 15cm-has better character than any other. Gurye local-stem length is 179cm, ear length is 38cm-is taken to be the best in the Geo-ecotypic.In the yield of leaf and seed, JukyeubJaso Is 727kg/10a, the greatest of all. In the leaf softness, allthe Inirorluced varieties are about 3.5 degrees, the Geo-ecotypic, about 2. The qualify of the introducedvat'ieties is better· than that of the Geo-ecotypic. Estimating on the chemical analysis of leaf,Jukyeubjaso has Protein 21.84%, Total carbohydrate 7.91%, Fe 126ppm, and Gurye lacal has Protein21.7 a, Total carbohydrate 8.4%, Fe 148ppm, expressing the highest. In correlation coefficients of leafchemical components, between protein and Total carbohydrate, Protein and Mn, protein and Fe, Pro-tein and Cu all the sorts show the positive correlation. Among them the Geo-ccoyplcs show the hlghestsignificance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.912-917
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• 2010

It was known that oil-filled transformer's life depended on insulating paper which was applied to transformers for insulating of transformer. Therefore when paper was aged, its electrical, mechanical and chemical characteristics were changed. Especially if operating temperature was high, paper was quickly damaged. As cellulose paper which was mainly used for solid insulation of transformers was degraded, the cellulose polymer chains broke down into shorter lengths and gases such as CO, $CO_2$, $CH_4$, $C_2H_4$ and so on were produced from paper. Also by-product known as furan compounds were producted from paper and it were dissolved within insulating oil. In this paper accelerating aging cell was aged during 60 hours at 100, 150, 180 and $200^{\circ}C$, respectively, so evaluating the chemical characteristics of cellulose paper by thermal. An it were performed analysis such as tensile strength(TS), dissolved gas analysis(DGA) and high performance liquid chromatography(HPLC). Also for analyzing of correlation between insulating degradation characteristics, it was performed linear regression method as statistical treatment.

• Food Science of Animal Resources
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• v.36 no.2
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• pp.145-151
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• 2016

The relationship between chemical compositions, meat quality traits, and palatability attributes in 10 primal cuts from Hanwoo steer carcasses were assessed. Sensory palatability attributes of Hanwoo beef were more closely related with fat content than to moisture or protein content. Among the chemical compositions, only fat had a significant correlation with juiciness (0.67, p<0.001), tenderness (0.32, p<0.05), and overall palatability (0.56, p<0.001). Oleic acid (%) was not significantly related with overall palatability (p>0.05). Overall palatability was negatively correlated with drip loss (−0.32, p<0.05), cooking loss (−0.36, p<0.05), and shear force (−0.54, p<0.01). The correlation between fat content and overall palatability was increased when higher fat cuts (Ansim, Dungsim, Chaekeut, Yangjee, and Kalbi) were analyzed, compared to lower fat cuts (Moksim, Abdari, Udun, Suldo, and Satae). Also, the correlation between shear force and overall palatability was decreased in lower fat cuts compared to higher fat cuts. Our results suggest that the palatability of Hanwoo beef can be improved by increasing fat content in muscles, as increased fat content leads to an increase in sensory tenderness, flavor, and juiciness.

• Bulletin of the Korean Chemical Society
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• v.20 no.8
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• pp.897-904
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• 1999

We have presented the thermodynamic, structural and dynamic properties of liquid pentane isomers - normal pentane, isopentane, and neopentane - using an expanded collapsed atomic model. The thermodynamic properties show that the intermolecular interactions become weaker as the molecular shape becomes more nearly spherical and the surface area decreases with branching. The structural properties are well predicted from the site-site radial, the average end-to-end distance, and the root-mean-squared radius of gyration distribution func-tions. The dynamic properties are obtained from the time correlation functions - the mean square displacement (MSD), the velocity auto-correlation (VAC), the cosine (CAC), the stress (SAC), the pressure (PAC), and the heat flux auto-correlation (HFAC) functions - of liquid pentane isomers. Two self-diffusion coefficients of liquid pentane isomers calculated from the MSD's via the Einstein equation and the VAC's via the Green-Kubo relation show the same trend but do not coincide with the branching effect on self-diffusion. The rotational re-laxation time of liquid pentane isomers obtained from the CAC's decreases monotonously as branching increases. Two kinds of viscosities of liquid pentane isomers calculated from the SAC and PAC functions via the Green-Kubo relation have the same trend compared with the experimental results. The thermal conductivity calculated from the HFAC increases as branching increases.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.5
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• pp.732-739
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• 2009

Pig slurry is a good soil amendment not only because of its high organic matter content, but also because of its ability to provide various nutrients. The objective of this study was to estimate the influence of raw and processed pig slurry application on pot soil over chemical fertilizer and non-amended control soil. Change in the chemical parameters (pH, organic matter (OM), organic carbon (OC), macro and micronutrients) and microbial mass of the treated soils were monitored over 30 to 90 days. Pot soil was treated with the recommended dose of pig slurry and chemical fertilizer, and was sampled after 30, 60 and 90 days of incubation. The least significanct difference (p<0.05) was observed on Fe, Cu, Zn, available P and K between treatments. All treatments increased N, P and K content and microbial mass of soil over control soil. Interestingly, no significant effects were detected on OM, OC, total bacteria, actinomycetes and fungi mass in soil irrespective of treatments given. However fungal and bacterial counts, as well as available nutrients, were found to be higher in processed slurry (PS)-treated soil compared to other soils. In general a significant correlation existed between the fungal count and OM, OC, Zn, T Kjeldahl N (TKN), available P and K of soil. A strong negative correlation was observed between pH and Fe in soil. This study clearly demonstrated that the use of processed manure as a fertilizer could be a key for sustainable livestock agriculture.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.1
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• pp.22-29
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• 1991

This study was experimented to obtain the basic information on the changeable aspect and improvement of soil fertility in newly-reclaimed sloped land. Silage corn was cultivated under the six different treatments for 4 years. The relation between the amount or ratio of annual changes of soil physico-chemical properties and yield of silage corn were analyzed. Soil bulk density was decreased in 3rd year at topsoil, but that decreased in 4th year at subsoil. Soil organic matter also decreased in 2nd year at topsoil, and decreased continuously at subsoil. Bulk density and hardness of soil depths showed significant negative simple correlation with dry matter yield and cation exchange capacity showed positive. Correlation coefficient of chemical properties with dry matter yield were low. The range of annual changes of moisture percent, hardness and organic matter were wider than the other properties. The significantly different of physical properties were higher than the chemical properties, and those of topsoil were higher than subsoil. According to multiple regression between yield and physico-chemical properties of subsoil, bulk density and cation exchange capacity were in the greatest contribution at the variations, but bulk density was greatest at the ratios.