• Bulletin of the Korean Chemical Society
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• 제19권11호
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• pp.1217-1221
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• 1998

We present results of molecular dynamic (MD) simulations for the segmental motion of liquid n-heptadecane in order to investigate conformational transitions from one rotational isomeric state to another. The behavior of the hazard plots for n-heptadecane obtained from our MD simulations are compared with that for polymer of Brownian dynamics (BD) study. The transition rate at the ending dihedrals of the n-heptadecane chain is much higher than that at the central dihedrals. In the study of correlation between transitions of neighboring dihedrals, the large value of c2 implies that some 30% of the transitions of the second neighbors can be regarded as following transitions two bonds away in a correlated fashion. Finally the analysis of multiple transitions and the number of times occurred in the initial 0.005 ns are discussed.

• Bulletin of the Korean Chemical Society
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• 제17권8호
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• pp.735-744
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• 1996

We present 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 Ⅰ-Ⅲ. Two of the three classes of models are collapsed atomic models while the third class is an atomistically detailed model. Model Ⅰ is the original Ryckaert and Bellemans' collapsed atomic model [Discuss. Faraday Soc. 1978, 66, 95] and model Ⅱ is the expanded collapsed model which includes C-C bond stretching and C-C-C bond angle bending potentials in addition to Lennard-Jones and torsional potentials of model Ⅰ. In model Ⅲ all the carbon and hydrogen atoms in the monomeric units are represented explicitly for the alkane molecules. Excellent agreement of the results of our MD simulations of model Ⅰ for n-butane with those of Edberg et al.[J. Chem. Phys. 1986, 84, 6933], who used a different algorithm confirms the validity of our algorithms for MD simulations of model Ⅱ for 14 liquid n-alkanes and of models Ⅰ and Ⅲ for liquid n-butane, n-decane, and n-heptadecane. The thermodynamic and structural properties of models Ⅰ and Ⅱ are very similar to each other and the thermodynamic properties of model Ⅲ for the three n-alkanes are not much different from those of models Ⅰ and Ⅱ. However, the structural properties of model Ⅲ are very different from those of models Ⅰ and Ⅱ as observed by comparing the radial distribution functions, the average end-to-end distances and the root-mean-squared radii of gyrations.

• Bulletin of the Korean Chemical Society
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• 제18권5호
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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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• 제34권7호
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• pp.2125-2130
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• 2013

A new nickel(II) complex $[NiL^1]^{2+}$ ($L^1$ = 1-(2-aminoethyl)-3-(N-{2-aminoethyl}aminomethyl-1,3-diazacyclohexane) containing one 1,3-diazacyclohexane ring has been prepared selectively by the metal-template condensation of formaldehyde with N-(2-aminoethyl)-1,3-propanediamine and ethylenediamine at room temperature. The complex reacts with nitroethane and formaldehyde to yield the pentaaza macrocyclic complex $[NiL^2]^{2+}$ ($L^2$ = 8-methyl-8-nitro-1,3,6,10,13-pentaazabicyclo[13.3.1]heptadecane) bearing one C-$NO_2$ pendant arm. The reduction of $[NiL^2]^{2+}$ by using Zn/HCl produces $[NiL^3(H_2O)]^{2+}$ ($L^3$ = 8-amino-8-methyl-1,3,6,10,13-pentaazabicyclo[13.3.1]heptadecane) bearing one coordinated C-$NH_2$ pendant arm that is readily protonated in acid solutions. The hexaaza macrocyclic complex $[NiL^4]^{2+}$ ($L^4$ = 8-phenylmethyl-8-nitro-1,3,6,8,10,13-hexaazabicyclo[13.3.1]heptadecane) bearing one N-$CH_2C_6H_5$ pendant arm has also been prepared by the reaction of $[NiL^1]^{2+}$ with benzylamine and formaldehyde. The nickel(II) complexes of $L^1$, $L^2$, and $L^4$ have square-planar coordination geometry in the solid states and in nitromethane. However, they exist as equilibrium mixtures of the square-planar $[NiL]^{2+}$ (L = $L^1$, $L^2$, or $L^4$) and octahedral $[NiL(S)_2]^{2+}$ species in various coordinating solvents (S); the proportion of the octahedral species $[NiL(S)_2]^{2+}$ is strongly influenced by the ligand structure and the nature of the solvent. Synthesis, spectra, and chemical properties of the nickel(II) complexes of $L^1-L^4$ are described.

• 한국식품저장유통학회지
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• 제21권3호
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• pp.381-387
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• 2014

식품의 방사선 조사는 식품 저장을 위한 성공적인 현대기술의 하나이지만 매우 신중하게 이루어져야 한다. 조사된 식품의 확인은 국제무역에서 소비자의 안전한 선택과 보호를 위해 가장 중요하다. 따라서 본 연구는 건조된 오징어와 문어에 전자선을 조사하여 선량별로 유도 생성되는 hydrocarbon류의 함량 및 분해패턴을 확인하였다. 비조사 시료와 선량별로 전자선 조사된 시료에서 지방을 추출한 뒤 solid phase extraction(SPE)방법을 이용하여 GC/MS로 확인하였다. 1, 3, 5, 7 및 10 kGy의 선량으로 전자선 조사된 건조 오징어와 문어에서 유도된 hydrocarbon류는 동일 선량에서 시료들의 지방산 조성에 따른 다른 생성률을 나타내었으며, 조사선량에 따라 증가하였다. 시료들에 다량 함유되어 있는 palmitic acid와 stearic acid로부터 생성된 1-tetradecene($C_{14:1}$), pentadecane($C_{15:0}$), 그리고 1-hexadecene($C_{16:1}$), heptadecane($C_{17:0}$)이 전자선 조사에 의해 유도된 주요 hydrocarbon류로 확인되었으며, 건오징어에서 hydrocarbon류 생성량이 건문어의 hydrocarbon류 생성량 보다 더 많음을 확인하였다. 이는 시료의 지방산 함유량에 따라 hydrocarbon류 생성량이 비례함을 알 수 있었다. 전자선 조사된 건오징어와 건문어에서 분석된 hydrocarbon류 중 1-tetradecene($C_{14:1}$), 1-hexadecene($C_{16:1}$) 그리고 heptadecane($C_{17:0}$)은 전자선 조사여부를 판별할 수 있는 지표로 활용될 수 있을 거라 사료된다.

• ALGAE
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• 제28권1호
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• pp.93-99
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• 2013

A freshwater cyanobacterium, Phormidium autumnale KNUA026, was isolated from puddles of icy water in Gyeongsan City, South Korea and its potential as a biofuel feedstock was investigated. Maximal growth was obtained when the culture was incubated at $25^{\circ}C$ and around pH 9.0. The total lipid content of the isolate was approximately 14.0% of dry weight and it was found that strain KNUA026 was able to autotrophically synthesize heptadecane ($C_{17}H_{36}$) which can be directly used as fuel without requiring a transesterification step. As this benthic cyanobacterium was capable of forming thick mats, it could be easily harvested by gravitational settling and this property may reduce the cost of production in commercial applications. Hence, P. autumnale KNUA026 appears to be a promising resource for use in the production of microalgae-based biofuels.

• 한국식품영양과학회지
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• 제43권12호
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• pp.1889-1895
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• 2014

건조된 국멸치와 지리멸치 및 밴댕이에 1, 3, 5, 7 및 10 kGy의 선량으로 전자선을 조사하여 비조사 시료와 조사된 시료에서 지방을 추출한 후 전자선 조사 시 유도 생성되는 hydrocarbon류를 florisil column chromatography를 이용하여 분리하였으며, hydrocarbon류의 함량 및 분해패턴은 GC/MS로 확인하였다. 전자선 조사된 건조 멸치류에서 palmitic acid로부터 생성되는 1-tetradecene($C_{14:1}$), pentadecane($C_{15:0}$)과 stearic acid로부터 1-hexadecene($C_{16:1}$), heptadecane($C_{17:0}$) 및 oleic acid로부터 8-heptadecene($C_{17:1}$), 1,7-hexadecadiene($C_{16:2}$)이 확인되었으며, 6종의 hydrocarbon류는 조사선량에 따라 증가하였다. 건조된 멸치류에서 유기용매에서 기인한 것으로 판단되는 pentadecane($C_{15:0}$) 및 heptadecane($C_{17:0}$)을 제외한 hydrocarbon류 중 8-heptadecene($C_{17:1}$)의 함량이 가장 높았으며, 다음으로 1-tetradecene($C_{14:1}$), 1-hexadecene($C_{16:1}$), 1,7-hexadecadiene($C_{16:2}$) 순으로 확인되었다. 따라서 전자선 조사된 건조 멸치류에서 분석된 hydrocarbon류 중 1-tetradecene($C_{14:1}$), 1-hexadecene($C_{16:1}$) 그리고 8-heptadecene($C_{17:1}$) 및 1,7-hexadecadiene($C_{16:2}$)은 전자선 조사 여부를 판별할 수 있는 유용한 지표로 활용될 수 있을 것이라고 사료된다.

• 한국미생물·생명공학회지
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• 제28권5호
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• pp.303-308
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• 2000

The character-istics of the volatile flavor components of traditional Korean Nuruk produced by Aspergillus oryze NR 3-6 and Penicillium expansum NR 7-7 were investigated. Volatile flavor of Nuruk was identified twenty-one components by gas chromatography-mass spectronmeter. Major flavor components were alkanes such as tridecan, tetradecan, penta-decane, hexadecane, heptadecane, octadecan, undecane, and dodecane.

• 한국환경과학회지
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• 제23권7호
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• pp.1253-1268
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• 2014

This study was investigated twenty two hazardous chemicals compounds for effluents of nine sewage treatment plants (STPs) and one waste water treatment plant (WWTP) in the Nakdong Ri-ver Basin. They are eleven phthalates(DMP, DEP, DIBP, DBP, BEEP, DNPP, DHP, DCP, DEHP, DNOP, Dinonyl phthalate, seven aliphatic hydrocarbons(n-Tridecane, n-Tetradecane, n-Pentadecan-e, n-Hexadecane, n-Heptadecane, n-Octadecane, n-Nonadecane, Isoquinoline, 2-Chloropyridine, 2-N-itrophenol, and Benzophenone. The twenty two compounds were analyzed by gas chromatograp-hy mass spectrometry (GC/MS) with liquid-liquid extraction (LLE). Twenteen of twenty two subs-tances were detected. They were DMP, DEP, DIBP, DBP, DEHP, n-Tetradecane, n-Pentadecane, n-Heptadecane, n-Octadecane, n-Nonadecane, Isoquinoline and Benzophenone. Among these, DEHP, DEP and Benzophenone were most frequently observed. They were obtained as $ND{\sim}36.881{\mu}g/L$, $ND{\sim}0.950{\mu}g/L$, $ND{\sim}2.019{\mu}g/L$, respectively. When the substances were calculated the average concentration at 10 points, the maximum average detection concentration was investigated at the Dalseocheon STP.

• 한국식품과학회지
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• 제35권6호
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• pp.1072-1078
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• 2003

방사선 조사된 건갑오징어로부터 유도된 hydrocarbon류와 2-alkylcyclobutanone류의 양을 비교 분석하였다. 건갑오징어의 지방추출은 Soxtec 기기를 이용하였으며, 지방추출 후 florisil 충진한 column을 이용하여 hydrocarbon류와 2-alkylcyclobutanone류를 분리하고 GC/MS 분석기기로 확인하였다. 0.5kGy부터 10kGy까지의 방사선 선량별로 조사된 각 시료에서 생성된 hydrocarbon류는 0.5kGy 이상 조사된 시료에서 검출되었으며 조사선량에 따라 생성량도 증가하였다. Palmitic acid와 stearic acid로부터 생성된 pentadecane과 1-tetradecene 그리고 heptadecane과 1-hexadecene의 함량이 가장 많았으며. 함량이 낮은 oleic acid로부터 생성된 8-heptadecene과 1,7-hexadecadiene은 가장 적은 함량으로 확인되었다. 2-Alkylcyclobutanone류는 0.5kGy 이상 조사된 시료에서 검출되었으며, palmitic acid로부터 생성된 2-dodecylcyclo-butanone이 두 시료 모두 가장 많이 생성되었다. Stearic acid로부터 생성된 2-tetradecylcyclobutanone 역시 조사선량과 지방산 함량에 따라 생성량이 증가되는 경향을 보였으나 그 함량이 너무 낮게 검출되었다. 본 연구 결과, 방사선 조사된 건오징어와 건갑오징로부터 생성된 hydrocarbon류는 조사선량에 따라 뚜렷하게 검출되었고 비조사 시료와 비교, 확인이 가능하여 방사선 조사 여부 판별뿐만 아니라 흡수선량을 예측하기 위한 marker로서 활용할 수 있으며, 2-alkylcyclobutanone류는 방사선 조사 유무의 marker로서 가능성을 확인하였다.