• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.3
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• pp.86-102
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• 2003

Polynitrogen molecules are of great interest as potential high energy-density materials, and hence such structures of various isomers of nitrogen clusters have been calculated using molecular modeling techniques by the researchers from various sectors of scientific institutions. In this article, the predicted meta-stable structures of these hypothetical molecules have been thoroughly reviewed.

• Nuclear Engineering and Technology
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• v.50 no.6
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• pp.907-914
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• 2018

In this article, we conducted molecular dynamics simulations to investigate the effect of applied strain and temperature on irradiation-induced damage in alpha-zirconium. Cascade simulations were performed with primary knock-on atom energies ranging between 1 and 20 KeV, hydrostatic and uniaxial strain values ranging from -2% (compression) to 2% (tensile), and temperatures ranging from 100 to 1000 K. Results demonstrated that the number of defects increased when the displacement cascade proceeded under tensile uniaxial hydrostatic strain. In contrast, compressive strain states tended to decrease the defect production rate as compared with the reference no-strain condition. The proportions of vacancy and interstitial clustering increased by approximately 45% and 55% and 25% and 32% for 2% hydrostatic and uniaxial strain systems, respectively, as compared with the unstrained system, whereas both strain fields resulted in a 15-30% decrease in vacancy and interstitial clustering under compressive conditions. Tensile strains, specifically hydrostatic strain, tended to produce larger sized vacancy and interstitial clusters, whereas compressive strain systems did not significantly affect the size of defect clusters as compared with the reference no-strain condition. The influence of the strain system on radiation damage became more significant at lower temperatures because of less annealing than in higher temperature systems.

• Transactions on Electrical and Electronic Materials
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• v.4 no.1
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• pp.1-6
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• 2003

We have studied the size confinement effect on the properties of melting-like transition of small icosahedral copper clusters using a classical molecular dynamics simulation based on a well fitted empirical potential. We investigated the caloric curves of icosahedron nanoclusters and the significant depression in the melting temperatures of the copper nanoclusters was compared with that of the bulk copper. A structural transitions from decahedral to icosahedral shapes were shown. As the cluster size increased, the melting temperature increased, and the latent heat increased but seem to be saturated. However, the specific heat was unrelated to the cluster size.

• Journal of Microbiology
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• v.34 no.2
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• pp.184-191
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• 1996

The cellular fatty acids and quinones of streptomycetes isolated from volcanic soils were analysed. The strains contained fatty acids of 14 to 17 carbon chains, and 12-methyltetradecanoic acid and 14 methylpentadecanoic acid were dominant in most strains. The total profiles consisted of 74% branched fatty acid family, 16.8% linear family and 8.2% unsaturated family. The largest cluster of grey spore meases defined by numerical classification was separated from the remainders in the principal component analysis, but the other clusters were overlapped with one another. In the analysis of respiratory quinones, all of the strains contained either the menaquinone of 9 isoprene units with 6 hydrogenations of 8 hydrogenations as the major species. The distribution of menaquinones among the clusters could provide an important key in the chemotaxonomy of streptomycetes.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.306-309
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• 2011

A lattice model based molecular clusters is presented to improve a classical equation of state(EOS) for volumetric properties in the critical region. The term is based on the two assumptions: (1) The Helmholtz energy is individually divided into classical and long-range density fluctuation contribution (2) All molecules form cluster near the critical region due to long-range density fluctuation. To formulate such molecular cluster, we extended the Veytsman statistics originally developed for the cluster due to hydrogen bonding. The probability function in the statistics is modified to represent the characteristics of long-range density fluctuation vanishing far from critical region. The proposed fluctuation contribution was incorporated into the Sanchez-Lacombe EOS and the combined model with 6 adjustable parameters has been tested against experimental VLE data for pure compounds. The combined model is found to well represent flatten critical isotherm for methane and top of the coexistence curve for the tested components.

• Bulletin of the Korean Chemical Society
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• v.13 no.5
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• pp.482-486
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• 1992

Ion-molecule reactions of acetylene and mixed acetylene-ammonia cluster ions are studied using an electron impact time-of-flight mass spectrometer. The present results clearly demonstrate that $(C_2H_2)_n^+$ cluster ion distribution represents a distinct magic number of n=3. The mass spectroscopic evidence for the enhanced structural stabilities of $[C_6H_4{\cdot}(NH_3)_m]^+$ (m=0-8) ions is also found along with the detection of mixed cluster $[(C_2H_2)_n{\cdot}(NH_3)_m]^+$ ions, which gives insight into the feasible structure of solvated ions. This is rationalized on the basis of the structural stability for acetylene clusters and the dissociation dynamics of the complex ion under the presence of solvent molecules.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.54.1-54.1
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• 2018

Recent observational studies suggest that the environmental effects can shape the evolution of galaxies in clusters. In an attempt to better understand this process, we perform idealized radiation-hydrodynamic simulations of RAM pressure stripping on star-forming galaxies using RAMSES-RT. We find that extended HI disks are easily stripped by moderate ICM winds, while there is no significant decrease in the total mass of molecular gas. RAM pressure tends to compress the molecular gas, leading to enhanced star formation especially when the gaseous disk is hit by edge-on winds. On the other hand, strong ICM winds that are expected to operate at the centre of clusters strip both HI and molecular gas from the galaxy. Interestingly, we find that the strong ICM winds can induce the formation of relatively dense (~1H/cc) HI gas clouds at a distance from the disk.

• Animal cells and systems
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• v.12 no.4
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• pp.261-267
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• 2008

The human chromosomes 2, 7, 12 and 17 show genomic homology around Hox gene clusters, is taken as evidence that these paralogous gene families might have arisen from a ancestral chromosomal segment through genome duplication events. We have examined protein data from vertebrate and invertebrate genomes to analyze the phylogenetic history of multi-gene families with three or more of their representatives linked to human Hox clusters. Topology comparison based upon statistical significance and information of chromosome location for these genes examined have revealed many of linked genes coduplicated with Hox gene clusters. Most linked genes to Hox clusters share the same evolutionary history and are duplicated in concert with each other. We conclude that gene families linked to Hox clusters may be suggestion of ancient genome duplications.

• BMB Reports
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• v.41 no.9
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• pp.670-677
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• 2008

A cDNA microarray composed of 2,028 different ESTs from two shrimp species, Penaeus monodon and Masupenaeus japonicus, was employed to identify yellow head virus (YHV)-responsive genes in hemocytes of P. monodon. A total of 105 differentially expressed genes were identified and grouped into five different clusters according to their expression patterns. One of these clusters, which comprised five genes including cathepsin L-like cysteine peptidase, hypothetical proteins and unknown genes, was of particular interest because the transcripts increased rapidly ($\leq$ 0.25 hours) and reached high expression levels in response to YHV injection. Microarray data were validated by realtime RT-PCR analyses of selected differentially expressed transcripts. In addition, comparative analysis of the hemocyte transcription levels of three of these genes between surviving and non-surviving shrimp revealed significantly higher expression levels in surviving shrimp.

• Bulletin of the Korean Chemical Society
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• v.23 no.1
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• pp.107-111
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• 2002

The OSS2 (Oj？me-Shavitt-Singer 2)[L. Oj？me et al., J. Chem. Phys. 109, 5547 (1998)] model for the solvated proton in water is examined for $H_2O,\;H_3O^+,\;H_5O_2^+,\;H_7O_3^+,\;and\;H_9O_4^-$ by molecular dynamics (MD) simulations. The equilibrium molecular geometries and energies obtained from MD simulations at 5.0 and 298.15 K agree very well with the optimized calculations.