• Korean Journal of Mathematics
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• v.22 no.4
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• pp.725-742
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• 2014

In this paper, we find all inequivalent classes of self-orthogonal codes over $Z_{p^2}$ of lengths $l{\leq}3$ for all primes p, using similar method as in [3]. We find that the classification of self-orthogonal codes over $Z_{p^2}$ includes the classification of all codes over $Z_p$. Consequently, we classify all the codes over $Z_p$ and self-orthogonal codes over $Z_{p^2}$ of lengths $l{\leq}3$ according to the automorphism group of each code.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.59.2-59.2
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• 2019

In this talk, I will explain the implications of a rapid appearance of dark energy between the redshifts ($z$) of one and two on the expansion rate and growth of perturbations. Using both Gaussian process regression and a parametric model, I show that this is the preferred solution to the current set of low-redshift ($z<3$) distance measurements if $H_0=73~\rm km\,s^{-1}\,Mpc^{-1}$ to within 1\% and the high-redshift expansion history is unchanged from the $\Lambda$CDM inference by the Planck satellite. Dark energy was effectively non-existent around $z=2$, but its density is close to the $\Lambda$CDM model value today, with an equation of state greater than $-1$ at $z<0.5$. If sources of clustering other than matter are negligible, we show that this expansion history leads to slower growth of perturbations at $z<1$, compared to $\Lambda$CDM, that is measurable by upcoming surveys and can alleviate the $\sigma_8$ tension between the Planck CMB temperature and low-redshift probes of the large-scale structure.

• Journal of the Korean Mathematical Society
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• v.35 no.4
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• pp.903-931
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• 1998

Since the modular curves X(N) = $\Gamma$(N)\(equation omitted)＊ (N =1,2,3) have genus 0, we have field isomorphisms K(X(l))(equation omitted)C(J), K(X(2))(equation omitted)(λ) and K(X(3))(equation omitted)( $j_3$) where J, λ are the classical modular functions of level 1 and 2, and $j_3$ can be represented as the quotient of reduced Eisenstein series. When N = 4, we see from the genus formula that the curve X(4) is of genus 0 too. Thus the field K(X(4)) is a rational function field over C. We find such a field generator $j_4$(z) = x(z)/y(z) (x(z) = $\theta$$_3$((equation omitted)), y(z) = $\theta$$_4$((equation omitted)) Jacobi theta functions). We also investigate the structures of the spaces $M_{k}$($\Gamma$(4)), $S_{k}$($\Gamma$(4)), M(equation omitted)((equation omitted)(4)) and S(equation omitted)((equation omitted)(4)) in terms of x(z) and y(z). As its application, we apply the above results to quadratic forms.rms.

• Journal of the Speleological Society of Korea
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• no.71
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• pp.5-11
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• 2006

A theoretical investigation of the solid phase mechanochemical synthesis of nano sized target product on the basis of dilution of the initial powdered reagent mixture by another product of an exchange reaction is presented. On the basis of the proposed 3 mode particle size distribution in mechanically activated mixture, optimal molar ratios of the components in mixture are calculated, providing the occurrence of impact friction contacts of reagent particles and excluding aggregation of the nanosized particles of the target reaction product. Derivation of kinetic equations for mechanochemical synthesis of nanoscale particles by the final product dilution method in the systems of exchange reactions is submitted. On the basis of obtained equations the necessary times of mechanical activation for complete course of mechanochemical reactions are designed. Kinetics of solid phase mechanosynthesis of nano TlCl by dilution of initial (2NaCl+$Tl_2SO_4$) mixture with the exchange reaction product (diluent,$zNa_2SO_4$, z=z*=11.25) was studied experimentally. Some peculiar features of the reaction mechanism were found. Parameters of the kinetic curve of nano TlCl obtained experimentally were compared with those for the model reaction KBr+TlCl+zKCl=(z+1) KCl+TlBr (z=z1*=13.5), and for the first time the value of mass transfer coefficient in a mechanochemical reactor with mobile milling balls was evaluated. Dynamics of the size change was followed for nanoparticle reaction product as a function of mechanical activation time.

• Journal of Microbiology and Biotechnology
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• v.27 no.11
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• pp.1994-1998
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• 2017

FtsZ, a bacterial cell-division protein, is an attractive antibacterial target. In the screening for an inhibitor of Staphylococcus aureus FtsZ, madurahydroxylactone (1) and its related derivatives 2-5 were isolated from Nonomuraea sp. AN100570. Compound 1 inhibited S. aureus FtsZ with an $IC_{50}$ of $53.4{\mu}M$ and showed potent antibacterial activity against S. aureus and MRSA with an MIC of $1{\mu}g/ml$, whereas 2-5 were weak or inactive. Importantly, 1 induced cell elongation in the cell division phenotype assay, whereas 2-5 did not. It indicates that 1 exhibits its potent antibacterial activity via inhibition of FtsZ, and the hydroxyl group and hydroxylactone ring of 1 are critical for the activity. Thus, madurahydroxylactone is a new type of inhibitor of FtsZ.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.405-406
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• 2005

A theoretical investigation of the solid-phase mechanochemical synthesis of nano-sized target product on the basis of dilution of the initial powdered reagent mixture by another product of an exchange reaction is presented. On the basis of the proposed 3-mode particle size distribution in mechanically activated mixture, optimal molar ratios of the components in mixture are calculated, providing the occurrence of impact-friction contacts of reagent particles and excluding aggregation of the nanosized particles of the target reaction product. Derivation of kinetic equations for mechanochemical synthesis of nanoscale particles by the final product dilution method in the systems of exchange reactions is submitted. On the basis of obtained equations the necessary times of mechanical activation for complete course of mechanochemical reactions are designed. Kinetics of solid phase mechanosynthesis of nano-TlCl by dilution of initial (2NaCl + $Tl_2SO_4$) mixture with the exchange reaction product (diluent, $zNa_2SO_4$, $z=z^*=11.25$) was studied experimentally. Some peculiar features of the reaction mechanism were found. Parameters of the kinetic curve of nano-TlCl obtained experimentally were compared with those for the model reaction KBr + TlCl + zKCl = (z + 1) KCl + TlBr ($z=z_l^*=13.5$), and for the first time the value of mass transfer coefficient in a mechanochemical reactor with mobile milling balls was evaluated. Dynamics of the size change was followed for nanoparticle reaction product as a function of mechanical activation time.

• Bulletin of the Korean Mathematical Society
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• v.52 no.1
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• pp.105-123
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• 2015

Let $f_{\beta}=h_{\beta}+\bar{g}_{\beta}$ and $F_a=H_a+\bar{G}_a$ be harmonic mappings obtained by shearing of analytic mappings $h_{\beta}+g_{\beta}=1/(2isin{\beta})log\((1+ze^{i{\beta}})/(1+ze^{-i{\beta}})\)$, 0 < ${\beta}$ < ${\pi}$ and $H_a+G_a=z/(1-z)$, respectively. Kumar et al. [7] conjectured that if ${\omega}(z)=e^{i{\theta}}z^n({\theta}{\in}\mathbb{R},n{\in}\mathbb{N})$ and ${\omega}_a(z)=(a-z)/(1-az)$, $a{\in}(-1,1)$ are dilatations of $f_{\beta}$ and $F_a$, respectively, then $F_a\tilde{\ast}f_{\beta}{\in}S^0_H$ and is convex in the direction of the real axis, provided $a{\in}[(n-2)/(n+2),1)$. They claimed to have verified the result for n = 1, 2, 3 and 4 only. In the present paper, we settle the above conjecture, in the affirmative, for ${\beta}={\pi}/2$ and for all $n{\in}\mathbb{N}$.

• The Korean Journal of Food And Nutrition
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• v.25 no.2
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• pp.274-283
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• 2012

The volatile flavor compounds of the essential oils from Ixeris dentate (Thunb.) Nakai and I. stolonifera A. Gray were investigated. The essential oils were extracted by hydro distillation extraction method. Ninety-three volatile flavor components were identified from I. dentate (Thunb.) Nakai essential oil. Hexadecanoic acid(33.73%) was the most abundant compound, followed by (Z,Z,Z,)-9,12,15-octadecatrienoic acid(18.59%), 6,10,14-trimethyl-2-pentadecanonel(10.39%) and phytol(5.21%). Ninety-seven volatile flavor components were identified from the essential oil of I. stolonifera A. Gray. Hexadecanoic acid was the most abundant component(39.7%), followed by (Z,Z,Z)-9,12,15-octadecatrienoic acid(12.63%), 9,12-octadecadienoic acid, ethyl ester(12.36%), pentacosane(5.2%) and 6,10,14-trimethyl-2-pentadecanone(3.18%). The volatile composition of I. dentate (Thunb.) Nakai was characterized by higher contents of phytol and phthalides than those of I. stolonifera A. Gray. The volatile flavor composition of I. stolonifera A. Gray can easily be distinguished by the percentage of sesquiterpene compounds against I. dentate (Thunb.) Nakai essential oil.

• Korean Journal of Plant Taxonomy
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• v.50 no.2
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• pp.148-153
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• 2020

Cleisostoma scolopendrifolium is an orchid species solely pollinated by the male bee Megachile yasumatsui. Although C. scolopendrifolium is an endangered species in Korea, little is known about its pollination mechanisms or the profiles of its chemical attractants. This study provides evidence that the Cleisostoma orchid attracts male bees as pollinators by mimicking female mating signals. We found 13 hydrocarbons in the Cleisostoma orchid flower presumed to be involved in sex pheromone mimicry: five alkanes (tricosane, pentacosane, heptacosane, nonacosane, and hentriacontane), compounds of cuticular hydrocarbons which function as chemical cues for the recognition of mates and species in social insects; and eight alkenes ((z)-9-tricosene, (z)-9-pentacosene, (z)-11-pentacosene, (z)-9-heptacosene, (z)-11-heptacosene, (z)-9-nonacosene, (z)-11-nonacosene, and (z)-11-hentriacontene) which serve as sex pheromones in several insects. We suggest that these hydrocarbons play a key role in the pollination mechanism between Cleisostoma orchids and Megachile bees.

• Korean Journal of Pharmacognosy
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• v.35 no.1 s.136
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• pp.35-40
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• 2004

Seven terpenoids, trans-phytol (1), ${\alpha}-spinasterol$ (2),${\beta}-sitosterol$ (3), oleanolic acid (4), traxasterol (5), ${\alpha}-spinasterol\;3-O-{\beta}-D-glucopyranoside$ (8), ${\beta}-spinasterol\;3-O-{\beta}-D-glucopyranoside$ (9), and three glycerides, 3-O-(9Z, 12Z, 15Z-octadecatrienoyl) glycerol (6), 3-O-(9Z, 12Z-octadecadienoyl) glycerol (7), 1, 2-O-(9Z, 12Z, 15Z-dioctadecatrienoyl)-3-O-${\beta}$- D-galactopyranosyl glycerol (10) were isolated from n-hexane fraction of the aerial parts of Saussurea nutans which was used as Korean traditional medicine to σeat rheumatic arthritis and dysmenorrhea. Their structures were established by chemical and spectroscopic methods.