• Bulletin of the Korean Chemical Society
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• v.27 no.5
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• pp.759-761
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• 2006

The compound B(C6F5)3 and its variations have been widely employed as alkyl carbanion abstracting reagents to produce metallocene cations for olefin polymerization.1-3 Weakly coordinating anions containing boron can greatly improve the activity of metallocene catalysts used in industrial olefin polymerization4 and thus group IV and V metallocene complexes of the organohydroborate anions have been intensively investigated.5 Recently, many organohydroborate metallocene complexes have been reported by Shore and co-workers.6-8 A common structural feature of those complexes is the three-center two electron M-H-B bond, like that observed in transition metal tetrahydroborate complexes but the reactivity and fluxional behavior of organohydroborate complexes are unlike those of the tetrahydroborate analogues.6 Although many of those metallocenes have been synthesized, few complexes could be used in the olefin polymerization and then this laboratory has been involved in the chemistry of the cyclic organohydroborate anions, and their group IV metallocene derivatives for the catalyst.9 Described here is recent work that led to the preparation of a novel cyclic organohydroborate hafnocene complex (h5-C5H5)2Hf ？(μ-H)2BC8H14 ,Cl. The hafnocene complex contains the three-center two electron bond Hf-H-B10 in which the hydride abstraction for olefin polymerization may occur.

• Korean Journal of Veterinary Research
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• v.22 no.1
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• pp.1-8
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• 1982

The effect of acetylcholine, oxytocin and prostaglandin $F_{2{\alpha}}$ ($PGF_{2{\alpha}}$) on cyclic nucleotide levels in estrogen-primed rabbit whole uterus were studied in the presence and absence of 1-methyl-3-isobutyl xanthine (MIX), a phosphodiestrase inhibitor, and indomethacin, a prostagandin inhibitor. In the absence of MIX, acetylcholine increased guanosine 3', 5'-cyclic monophosphate (cGMP), but had no effect on adenosine 3', 5'-cyclic monophosphate (cAMP) levels. In contrast, oxytocin had no influence on cGMP, but decreased cAMP levels. $PGF_{2{\alpha}}$ increased cGMP and decreased cAMP levels. MIX increased both cAMP and cGMP levels. Oxytocin and $PGF_{2{\alpha}}$ further increased cGMP levels, indicating activation of guanylate cyclase activity. The ratio of cAMP/cGMP was decreased by uterine stinulants both in presence and absence of MIX. Indomethacin elevated cAMP and cGMP revels. The effects of uterine stimulants in the presence of indomethacin on cyclic nucleotide levels were varied from tissue to tisse. In general, oxytocin decreased cGMP and $PGF_{2{\alpha}}$ increased cAMP/cGMP levels, but the effects were statisically nonsignicficant. The cAMP/cGMP ratio was increased by uterine stimulant in the presence of indomethacin. In conclusion, uterine stimulants eased cAMP/cGMP ratio which indicates that the uterine stimulants have opposing effects on adenylate cyclase and guanylate cyclase activities. The endometrium plays a role in the regulation of cyclic nucleotide levels and uterine contraction by means of PG synthesis. Indomethacin has an unknown activities besides both of PG synthetase and phosphodiesterase inhibitions.

• Bulletin of the Korean Chemical Society
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• v.18 no.1
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• pp.14-18
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• 1997

Sulconazole nitrate, C18H16Cl3N3O3S, crystallizes in monoclinic, space group C2/c, with a=14.401(1), b=8.051(1), c=34.861(2) Å, β=95.9(1)°, g=0.58 mm-1, Dc=1.523 g/cm3, Dm=1.522 g/cm3, F(000)=1888.0, and z=8. Intensities for 2460 unique reflections were measured on a CAD4 diffractometer with graphited-monochromated Mo-Kα radiation. The structure was solved by direct method and refined by full matrix least squares to a final R=0.071 for 2182 reflections (Io > 2σIo). The bond lengths and angles are comparable with the values found in the analogues imidazole derivatives. The 2,4-dichlorophenyl ring(A) and the p-chlorophenyl ring(B) are almost planar with different heights [dihedral angle 17.3°] while the imidazole ring(C) is nearly perpendicular to the two phenyl rings[dihedral angles about the two rings A, B are 110.8° and 96.1° respectively]. In order to understand the overall conformation we calculated the selected distances (l1, l2, l3) among the center of the three rings and considered the imaginary plan D[C(7), C(9) and C(16)]. The two polar group S(8) and N(19) do not have gauche conformation and l2 value (4.47 Å) is shorter than the other imidazole derivatives. One -NO3 group are hydrogen bonded the two neighbored sulconazole molecules. The molecular crystal packing is also formed by two hydrogen bondings and van der Waals forces.

• Journal of Powder Materials
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• v.23 no.2
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• pp.108-111
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• 2016

$Y_2O_3-H_3BO_3:Eu^{3+}$ powders are synthesized using a mechanical alloying method, and their photoluminescence (PL) properties are investigated through luminescence spectrophotometry. For samples milled for 300 min, some $Y_2O_3$ peaks ([222], [440], and [622]) and amorphous formations are observed. The 300-min-milled mixture annealed at $800^{\circ}C$ for 1 h with Eu = 8 mol% has the strongest PL intensity at every temperature increase of $100^{\circ}C$ (increasing from 700 to $1200^{\circ}C$ in $100^{\circ}C$ increments). PL peaks of the powder mixture, as excited by a xenon discharge lamp (20 kW) at 240 nm, are detected at approximately 592 nm (orange light, $^5D_o{\rightarrow}^7F_1$), 613 nm, 628 nm (red light, $^5D_o{\rightarrow}^7F_2$), and 650 nm. The PL intensity of powder mixtures milled for 120 min is generally lower than that of powder mixtures milled for 300 min under the same conditions. PL peaks due to $YBO_3$ and $Y_2O_3$ are observed for 300-min-milled $Y_2O_3-H_3BO_3$ with Eu = 8 mol% after annealing at $800^{\circ}C$ for 1 h.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.4
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• pp.648-657
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• 1997

In order to investigate the polymorphism of wagnerite, the single phase of$Mg_3(PO_4)_2$ was synthesized by heating the stoichiometric mixture of $Mg_3(PO_4)_2$ and $MgF_2$ in a sealed platinum tube at $1040^{\circ}C$ (or 3 hours, One reversible inversion was detected at $1255^{\circ}C$ and the thermal decomposition was not observed until it reached the melting point. As a result, wagnerite is thermally stable enough to be used as pigments for glazes and plastics if substituted with divalent metal ions. The contractions of d-values in $Zn_4P_2O_8F_2$ and $Zn_3MgP_2O_8F_2$ phases were observed by the substitution with metal ions which resulted in intense purple, gold and green colors. Among the several attempts of charge - coupled sub-stitution, only $A^{1+}A_3^{2+}X^{5+}X^{6+}O_8_F2$ compositions were successful to synthesize the wagnerite phase.

• Journal of the Korean Ceramic Society
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• v.45 no.9
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• pp.561-566
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• 2008

Carbon fiber fabric-silicon carbide composites were fabricated by liquid silicon infiltration (LSI) process. The porous two-dimensional carbon fiber fabric performs were prepared by 13 plies of 2D-plain-weave fabric in a three laminating method, [0/90], [${\pm}45$], [$0/90/{\pm}45$] lay-up, respectively. Before laminating, a thin pyrolytic carbon (PyC) layer deposited on the surface of 2D-plain weave fabric sheets as interfacial layer with $C_3H_8$ and $N_2$ gas at $900^{\circ}C$. A densification of the preforms for $C_f-Si-SiC$ matrix composite was achieved according to the LSI process at $1650^{\circ}C$ for 30 min. in vacuum atmosphere. The bending strength of the each composite were measured and the microstructural consideration was performed by a FE-SEM.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.2
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• pp.146-150
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• 1990

This study was conducted to investigate the genetic analysis of esterase isozymes in maize with tillers. The materials used for the study were stele tissue for five day old seedlings of IK inbred line with tiller and A-type inbred line with no tiller, their Fl and F,. The methods employed for the study were same as previous report by Lee and Choe. A total of thirteen isoesterase enzyme bands were identified and five zones were distinguised according to both migration distance and genetic segregation patterns. The E$\sub$0.3/, E$\sub$0.4/ and E$\sub$0.5/ loci appeared from orgin to 0.5cm migration distance were controlled by the two alleles in (IK/A-type)F$_2$ and the E$\sub$0.3/+E$\sub$0.4/ of variants was controlled by codominant alleles. The E$\sub$1.0/, E$\sub$1.2/, E$\sub$1.5/ and E$\sub$1.8/ loci appeared from 1.0cm to 1.8cm were also controlled by the two alleles. However, the null band was functioned alleles. The E$\sub$2.8/, E$\sub$3.0/ and E$\sub$3.5/ loci appeared from 2.8cm to 3.5cm migration distance were very active and near location. A total of individuals with two paried bands of these loci were more than those of three paired bands(x$^2$=0.327$\^$**/). The activity of bands appeared over 3.8cm were very low and these were controlled by the two alleles. In above results, genetic segregations of stele tissue of maize with tillers were suggested to be controlled by Mendelian genetic laws.

• Journal of the Korean Electrochemical Society
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• v.8 no.1
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• pp.37-41
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• 2005

We investigated the electrochemical properties and microstructure on the various argon deposition pressure $(P_{Ar})$ and the low annealing temperature $(400^{\circ}C)$ of $LiCoO_2$ cathodes, which deposited by R.F. magnetron sputtering. The microsuucture and composition of Lico02 thin film was changed as a function of $P_{Ar}$. The capacity and electrochemical properties were improved with Ph of $LiCoO_2$ thin films. The cycling reversibility and stability of thin film batteries were measured by cyclic voltammetry and the constant current charge-discharge. The physical properties of cathode films were analyzed by ICP-AES, XRD, SEM and AFM for composition, crystallization and surface morphology.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.5
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• pp.704-711
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• 2020

Objective: Muscle fiber types, numbers and area are crucial aspects associated with meat production and quality. However, there are few studies of pig muscle fibre traits in terms of the detection power, false discovery rate and confidence interval precision of whole-genome quantitative trait loci (QTL). We had previously performed genome scanning for muscle fibre traits using 183 microsatellites and detected 8 significant QTLs in a White Duroc×Erhualian F₂ population. The confidence intervals of these QTLs ranged between 11 and 127 centimorgan (cM), which contained hundreds of genes and hampered the identification of QTLs. A whole-genome sequence imputation of the population was used for fine mapping in this study. Methods: A whole-genome sequences association study was performed in the F₂ population. Genotyping was performed for 1,020 individuals (19 F₀, 68 F₁, and 933 F₂). The whole-genome variants were imputed and 21,624,800 single nucleotide polymorphisms (SNPs) were identified and examined for associations to 11 longissimus dorsi muscle fiber traits. Results: A total of 3,201 significant SNPs comprising 7 novel QTLs showing associations with the relative area of fiber type I (I_RA), the fiber number per square centimeter (FN) and the total fiber number (TFN). Moreover, one QTL on pig chromosome 14 was found to affect both FN and TFN. Furthermore, four plausible candidate genes associated with FN (kinase non-catalytic C-lobe domain containing [KNDC1]), TFN (KNDC1), and I_RA (solute carrier family 36 member 4, contactin associated protein like 5, and glutamate metabotropic receptor 8) were identified. Conclusion: An efficient and powerful imputation-based association approach was utilized to identify genes potentially associated with muscle fiber traits. These identified genes and SNPs could be explored to improve meat production and quality via marker-assisted selection in pigs.

• Journal of the Korean Ceramic Society
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• v.31 no.6
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• pp.685-693
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• 1994

Sublimation vapour pressures and sublimation enthalpy of anhydrous bismuth trifluoride have been measured by the continuous gravimetric Cnudsen-effusion method from 639-7 to 782.8 K. Additional effusion measurements have also been made from 750.6 to 863.1 K by the torsion-effusion method. Based on a correlation of subHo298.15 and subSo298.15, a recommended P(T) equation has been obtained for BiF3(s); logP= -C/T+5.2375logT-3.205$\times$10-3+4.661$\times$104/T2+1.348 where P is in Pa, T in Kelvin, subHo298.15 in kJ mol-1 and C=( subHo298.15-13.5149)/1.9146$\times$10-2. Condensation coefficients and their temperature dependence have been derived from the effusion measurements.