• Elastomers and Composites
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• v.40 no.3
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• pp.174-180
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• 2005

Sonochemical synthesis of fullerene oxides $[C_{70}O_n](n=1{\sim}2)$ by fullerene$[C_{70}]$ and metal hexacarbonyl complexes $M(CO)_6$(M=Cr, Mo, W) took place under air atmosphere. The reactivity of fullerene$[C_{70}]$ and several metal hexacarbonyl complexes $M(CO)_6$(M=Cr, Mo, W) under same ultrasonic condition increased in the order of $Mo(CO)_6$ > $W(CO)_6$ > $Cr(CO)_6$. The MALDI-TOF-MS, UV-visible spectra, and HPLC analysis confirmed that the products of sonochemical reaction were $[C_{70}O_n](n=1{\sim}2)$.

• Journal of Applied Biological Chemistry
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• v.43 no.1
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• pp.5-11
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• 2000

Three cDNA clones encoding rice calmodulin (CaM) isoforms (OsCaM-1, OsCaM-2, and OsCaM-3) were isolated from a rice cDNA library constructed from suspension-cultured rice cells treated with fungal elicitor. The coding regions of OsCaM-1 and O.sCaM-2 were 89% homologous at DNA Ievel, whereas the 5' and 3' untranslated regions were highly divergent. The polypeptides encoded by OsCaM-1 and OsCaM-2 was identical except two conservative substitution at position 8 and 75. The coding region of OsCaM-3 was consist of a typical conserved CaM domain and an additional C-terminal extension. The amino acid sequence of conserved CaM domain of OsCaM-3 shared only 86% identity with that OsCaM-1. The OsCaM-3 cDNA is belongs to a novel group of calmodulin gene due to its C-terminal extension of 38 amino acids, a large number of which are positively charged. The extension also contains a C-terminal CaaX-box prenylation site (CVlL). Genomic Southern analysis revealed at least six copies of CaM or CaM-related genes, suggesting that calmodulin may be represented by a small multigene family in the rice geneme. Expression of OsCaM gene was examined through Northern blot analysis. Transcript level of OsCaM-3 was increased by treatment with a fungal elicitor, whereas the OsCaM-1 and OsCaM-2 genes did not respond to the fungal elicitor. The expression of OsCaM-3 gene was remarkable inhibited in the rice cells treated with cyclosporine A, calcinurin inhibitor.

• Journal of the Korean Mathematical Society
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• v.36 no.1
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• pp.97-107
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• 1999

Given a C-dynamical system (A, G, $\alpha$) with a locally compact group G, two kinds of C-algebras are made from it, called the full C-crossed product and the reduced C-crossed product. In this paper, we extend the theory of the classical C-crossed product to the C-dynamical system (A, G, $\alpha$) with a left-cancellative semigroup M with unit. We construct a new C-algebra A $\alpha$rM, the reduced crossed product of A by the semigroup M under the action $\alpha$ and investigate some properties of A $\alpha$rM.

• The Pure and Applied Mathematics
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• v.2 no.2
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• pp.111-114
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• 1995

A C$\^$$\infty$/ manifold is a pair (M, C) where a) M is a Hausdorff topological space such that every point $\chi$$\in$M has a neighborhood homeomorphic to an open subset of R$^n$. b) C is a collection of these homeomorphisms whose domains cover M. If ø, $\psi$ $\in$ C then ø o $\psi$$\^$-1/ is C$\^$$\infty$/. c) C is maximal with respect to (b).(omitted)

• Journal of the Korean Magnetics Society
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• v.7 no.4
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• pp.173-179
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• 1997

Change in phases, microstructures, and magnetic properties by the variation of quench rate and heat treatment were investigated for melt-spun $Fe_{77}Pr_{15}C_8$ ribbons. The amorphization of as-spun ribbons increased as the quench rate increased. As a result, the ribbon quenched at 40 m/s was almost entirely amorphous. Similarly to cast alloys, the primary phase in crystalline ribbons quenched at 10 m/s was $\alpha$-Fe followed by the secondary $Fe_{17}Pr_2C_x$. Crystalline phases were still dominant in the ribbon spun at 20 m/s, but in this case crystallization of $Fe_{17}Pr_2C_x$ was remarkable with a little suppression of $\alpha$-Fe. At 30 m/s an amorphous phase obviously dominated in the as-spun ribbons with small fraction of crystals. Therefore, substantial amount of hard magnetic $Fe_{14}Pr_2C$ was not obtained from the as-spun state but, as in cast alloys, produced only by a solid-state transformation. Within a few minutes fine grains of $Fe_{14}Pr_2C$ were easily obtained at relatively low temperature when the degree of amorphization of as-spun ribbons was higher. The grain size of $Fe_{14}Pr_2C$ was well less than 1${\mu}{\textrm}{m}$. The ribbons quenched at 20 or 30 m/s yielded higher coercivities after heat treatment.

• Korean Journal of Animal Reproduction
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• v.16 no.2
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• pp.117-123
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• 1992

This Study was carried out ot investigate the effects of concentration and equilibration time of cryoprotective aagents on survival rate of slowly and ultrarapidly frozen porcine embryos. The porcine embryos following dehydration by cryoprotective agents and 0.25M sucrose were slowly freezed(from 2$0^{\circ}C$ to -7$^{\circ}C$/-1$^{\circ}C$/min., from -7$^{\circ}C$ to -35$^{\circ}C$/-0.2$^{\circ}C$/min., from -35$^{\circ}C$ to -38$^{\circ}C$/-0.3$^{\circ}C$/min.) by Cell Freezer and directly plunged into liquid nitrogen and thawed in 38$^{\circ}C$ water bath. Survival rate was defined as development rate to the morula and blastocyst stage after in vitro culture or by FDA test. The results are summarized as follows : 1. The survival rates of porcine embryos after slow frozen-thawing in the freezing medium of 0.25M sucrose added 2.0M glycerol, 3.0M DMSO, 2.0M propanediol or 2.0M glycerol＋2.0M propanediol was 80.6, 84.7, 75.0 or 78.8%, respectively. 2. The survival rates of porcine embryos after slow frozen-thawing in the freezing medium of 0.50M sucrose added 2.0M glycerol, 3.0M DMSO, 2.0M propanediol or 2.0M glycerol＋2.0M propanediol was 80.9, 82.4, 73.1 or 77.1%, respectively. 3. The survival rates of porcine embryos after ultrarapid frozen-thawing in the freezing medium of 0.25M sucroese added 2.0M glycerol, 3.0M DMSO, 2.0M propanediol or 2.0M glycerol＋2.0M propanediol was 65.3, 68.6, 63.2 or 59.9%, respectively. 4. The survival rates of porcine embryos after ultrapid frozen-thawing in the freezing medium of 0.50M sucrose added 2.0M glycerol, 3.0M DMSO, 2.0 propanediol or 2.0M glycerol＋2.0M propanediol was 67.5, 62.9, 56.9, or 62.8%, respectively. 5. The higher survival rate of porcine embryos was attained at the short period ofequilibration time(5min.) in the freezing medium added 0.25M sucrose and 3.0 DMSO compared to those of 10 or 20min. equilibration time in the same condition.

• Kyungpook Mathematical Journal
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• v.62 no.1
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• pp.133-166
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• 2022

Let M be a semi-invariant submanifold with almost contact metric structure (𝜙, 𝜉, 𝜂, g) of codimension 3 in a complex space form M_n+1(c) for c ≠ 0. We denote by S and R_𝜉 be the Ricci tensor of M and the structure Jacobi operator in the direction of the structure vector 𝜉, respectively. Suppose that the third fundamental form t satisfies dt(X, Y) = 2𝜃g(𝜙X, Y) for a certain scalar 𝜃 ≠ 2c and any vector fields X and Y on M. In this paper, we prove that if it satisfies R_𝜉𝜙 = 𝜙R_𝜉 and at the same time S𝜉 = g(S𝜉, 𝜉)𝜉, then M is a real hypersurface in M_n(c) (⊂ M_n+1(c)) provided that $\bar{r}-2(n-1)c{\leq}0$, where $\bar{r}$ denotes the scalar curvature of M.

• Journal of the Korean Mathematical Society
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• v.44 no.1
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• pp.35-54
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• 2007

Let $M_c$ = M(2, 0, c) be the moduli space of O(l)-semistable rank 2 torsion-free sheaves with Chern classes $c_1=0\;and\;c_2=c$ on a K3 surface X, where O(1) is a generic ample line bundle on X. When $c=2n\geq4$ is even, $M_c$ is a singular projective variety equipped with a holomorphic symplectic structure on the smooth locus. In particular, $M_c$ has trivial canonical divisor. In [22], O'Grady asks if there is any symplectic desingularization of $M_{2n}$ for $n\geq3$. In this paper, we show that there is no crepant resolution of $M_{2n}$ for $n\geq3$. This obviously implies that there is no symplectic desingularization.

• Journal of Ocean Engineering and Technology
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• v.1 no.2
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• pp.83-92
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• 1987

Inorder ot estimate the running life of turbine rotors, fatigue crack propagation low, da/dN = C(${\DELTA}K)^m$, proposed by paris et al. has been widely applied. In this study, fatigue crack propagation rates for 16 samples of 1% Cr-Mo-V rotor steel were measured and statistical characteristics of m and C values in above equation were reviewed. The results are summarized as follows. 1. C and m follow a log-normal distribution and normal distribution, respectively. And the relation of C and shows a strong negative correlation. 2. Fatigue crack propagation equation can be expressed as da/dN=$4.11{\times}10^{-4}({\Delta}K/153.8)^m$, introducing the ralationship C=$C_oK_o^{-m}$. In this case, contribution of $C_o$ distribution to the distribution of log C shows very small compared to degrees of contribution by m.

• Journal of Ginseng Research
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• v.11 no.2
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• pp.136-144
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• 1987

Biosynthesis of saponins from acetate, mevalonate and squalene using root slices of panax ginseng C.A. Meyer was investigated. The sliced roots (2g) were incubated with the reaction mixture containing 20 M sodium acetate ($500\mu$Ci [U-$^{l4}C$]-acetate),10 mM mevalonate ($25\mu$Ci [2-$^{l4}C$]-mevalonate) or 10 mM swidme ($10\mu$Ci [4,8,12,13,17,21-$^3H$]-squalene) respectively at $30^{\circ}C$ for 72 hours. Biosynthesis of labelled ginseng saponine from [U-l4C]-acetate, [2-$^{l4}C$]-mevalonate and [4,8,12,13,17,21-$^3H$]-squalene was confirmed by autoradiography. Analysis of the products from [U-$^{l4}C$]-acetate by T.L.C. showed that the % radioactivities in panaxadiol, panaxatriol, squalene and mevalonate were found to be 2.1%, 2.7%, 2.6% and 0.2% respectively. Some of the sugars were also highly labelled. Analysis of the products from [2-$^{l4}C$]-mevalonate by T.L.C. showed that squalene was highly labelled and the products from [4,8,12,13,17,21-$^3H$]-squalene showed that panaxadiol, panaxatriol and sterol were highly labelled. From the above results, it was suggested that saponine might be synthesized from acetate via mevalonate-squalene route as expected in ginseng root.