• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.04a
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• pp.143-149
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• 1997

the horizontal corrosion fatigue tester has been developed for investigating environmental strength. Using this tester, we investigated about corrosion fatigue caracteristic for A106 GrB steel weldments in 3.5% synthetic seawater and room temperature. Considered parameter is only frequency of 1,3 and 5Hz. and Corrosion fatigue crack length was measured by DC potential difference method. From the results, we could find that the horizontal corrosion fatiued tester could be well applied to estimation of fatigue strength. and In case of 5Hz, corrosion fatigue crack growth path of A106 GrB steel weldment was transgranular, and of 1 and 3Hz showed that transgranular and intergranular was mixed. Also, Corrosion fatigue crack growth caracteristic values estimated in each frequency were C=9.33 x 10-9 and m=2.93 in 1Hz, C=9.77x10-10 and m=3.47 in 3Hz, C=1.02x10-10 and m=4.05 in 1Hz

• Bulletin of the Korean Chemical Society
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• v.25 no.4
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• pp.485-490
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• 2004

Silver-needle shaped crystals of $KLa_2Sb_3S_9$ from $K_2S_x$ flux and $KSm_2Sb_3Se_8$ from NaCl/KCl flux reactions were obtained and their crystal structures were determined by the single crystal X-ray diffraction method. $KLa_2Sb_3S_9$ crystallizes in the orthorhombic noncentrosymmetric space group $P2_12_12_1$ (No.19) with a unit cell of a = 4.220(3) ${\AA}$, b = 24.145(2) ${\AA}$, c = 14.757(5) ${\AA}$ and Z = 4. $KSm_2Sb_3Se_8$ crystallizes in the orthorhombic space group Pnma (No.62) with a unit cell of a = 16.719(3) ${\AA}$, b = 4.1236(8) ${\AA}$, c = 22.151(4) ${\AA}$ and Z = 4. Both structures have three-dimensional tunnel frameworks filled with $K^+$ ions. $KSm_2Sb_3Se_8$ is an ordered version of $ALn_{1{\pm}X}B_i{4{\pm}X}S_8$, and it is made up of NaCl-type and $Gd_2S_3$-type fragments. $KLa_2Sb_3S_9$ also contains building fragments similar to those of $KSm_2Sb_3Se_8$, however, there are chalcogen-chalcogen bonds in the $Gd_2S_3$-type fragment. The formula of $KLa_2Sb_3S_9$ can be described as $(K^+ )(La^{3+})_2(Sb^{3+})^3(S^{2-})_7(S_2^{2-})$.

• Journal of the Korean Chemical Society
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• v.37 no.1
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• pp.76-82
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• 1993

Two crystal structures of fully dehydrated Ca(II) and Tl(I) exchanged zeolite A, $Ca_{5.6}Tl_{0.8}-A (a = 12.242(2){\AA})\;and\;Ca_{1.4}Tl_{9.2}-A (a = 12.191(1){\AA})$, have been determined by single-crystal X-ray diffraction methods in the cubic space group Pm3m at 21(1)$^{\circ}C$. All crystals were ion exchanged in flowing streams of mixed $Ca(NO_3)_2\;and\;TINO_3$ aqueous solution with total concentration of 0.05M. All crystals were dehydrated at 360$^{\circ}C$ under $2{\times}10^{-6}\;torr$ for two days. The structures of the dehydrated $Ca_{5.6}Tl_{0.8}-A$ and $Ca_{1.4}Tl_{9.2}-A$ were refined to the final error indicies, $R_1$ = 0.072 and $R_2$ = 0.076 with 179 reflections for I > 3$\sigma$(I), and $R_1$ = 0.048 and $R_2$ = 0.043 with 226 reflections for I > 3$\sigma$(I), respectively. In each structure, Ca(II) ions are located on threefold axes associated with three 6-ring oxygens. $Ca^{2+}$ ions prefer to 6-ring sites and $Tl^+$ ions prefer to 8-ring sites when total number of exchanged cations per unit cell is more than 8.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.12 no.1
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• pp.62-68
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• 1999

Ferroelectric $Sr_{0.7}/B_{2.3}(Ta_{1-x}Nb_x)_2O_9$(x=0, 0.1, 0.2, 0.3) thin films were deposited on $Pt/SiO_2/Si$ substrate by MOD(Metalorganic Decomposition) process. Metal carboxylate and metal alkoxide were used as precursors, and 2-methoxyethanol, xylene as solvents. After spin coating, thin films were pre-annealed at $400^{\circ}C$, followed by RTA(Rapid Thermal Annealing) and final annealing at $800^{\circ}C$ in oxygen atmosphere. These procedures were repeated three times to obtain thin films with the thickness of $2000{\AA}$. To enhance the nucleation and growth of layered-perovskite phase, thin films were rapid-thermally annealed above $720^{\circ}C$ in oxygen atmosphere. As RTA temperature increased, fluorite phase was transformed to layered-perovskite phase. And the change of Nb contents affected dielectric / electrical properties and microstructure. The ferroelectric characteristics of $Sr_{0.7}/B_{2.3}(Ta_{1-x}Nb_x)_2O_9$ thin film were Pr=8.67 $\mu{C}/cm^2$, Ec=62.4kV/cm and $I_{L}=1.4\times10^{-7}A/cm^2$ at the applied voltage of 5V, respectively.

• Journal of the Korean Vacuum Society
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• v.15 no.5
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• pp.527-533
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• 2006

Spinel $LiNi_xMn_{2-x}O_4$ thin films were synthesized up to x = 0.9 by a sol-gel method employing spin-coating. The Ni-substituted films were found to maintain cubic structure at low x but to exhibit tetragonal structure for $x{\geq}0.6$. Such cubic-tetragonal phase transition indicates that $Ni^{3+}(d7)$ ions with low-spin $(t_{2g}^6,e_g^1)$ state occupy the octahedral sites of the compound, thus being subject to the Jahn-Teller distortion. By x-ray photoelectron spectroscopy both $Ni^{2+}$ and $Ni^{3+}$ ions were detected. Optical properties of the $LiNi_xMn_{2-x}O_4$ films were investigated by spectroscopic ellipsometry (SE) in the visible?ultraviolet range. The measured dielectric function spectra by SE mainly consist of broad absorption structures attributed to charge-transfer (CT) transitions, $O^{2-}(2p){\rightarrow}Mn^{4+}(3d)$ for 1.9 $(t_{2g})$ and $2.8{\sim}3.0$ eV $(e_g)$ structures and $O^{2-}(2p){\rightarrow}Mn^{3+}(3d)$ for 2.3 $(t_{2g})$ and $3.4{\sim}3.6$ eV $(e_g)$ structures. Also, sharp absorption structures were observed at about 1.6, 1.7, and 1.9 eV, interpreted as due to d-d crystal-field transitions within the octahedral $Mn^{3+}$ ion. The strengths of these absorption structures are reduced by the Ni substitution. Rapid reduction of the CT transition strength involving the eg states for x = 0.6 is attributed to the reduced wavefunction overlap between the $e_g$ and the $O^{2-}(2p)$ states due to the tetragonal extension of the lattice constant by the Jahn-Teller effect.

• Clinical and Experimental Reproductive Medicine
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• v.12 no.2
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• pp.59-64
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• 1985

This investigation represents a cytogenetic study of 382 women with primary amenorrhea. 235 cases (61.5%) showed normal karyotype, 46, XX and l47 cases (38.5%) showed chromosomal abnormalities. Of 144 females with cytogenetic abnormalities, 44 cases (30.0%) showed a 45, X constitution: 37 cases (25.2%) with 45, X/46, XX: 3 (2.0%) 45, X/47, XXX: 11 (7.5%) 45, X/46, XX/47, XXX: 1 (0.7%) 45, X/46, XY: 3 (2.0%) 46, $XX_{p-}$: 2 (1.4%) 46, $XX_{q-}$: 6 (4.1%) 46, X, i ($X_q$): 1 (0.7%) 45, X/46, $XX_{q+}$: 1 (0.7%) 45, X/46, XX, inv(X): 1 (0.7%) 45, X, inv (9)/47, XXX, inv(9). 36 women (24.5%) had a 46, XY constitution and 1 case (0.7%) had a 47, XXX constitution.

• Bulletin of the Korean Chemical Society
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• v.16 no.10
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• pp.923-929
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• 1995

Four crystal structures of M3-A (M3Na9-xHx-A, M=Rb or K and x=1 or 0), Rb3Na8H-A(a=12.228(1) Å and R1=0.046), Rb3Na9-A (a=12.258(3) Å and R1=0.058), K3Na8H-A (a=12.257(3) Å and R1=0.048) and K3Na9-A (a=12.257(3) Å and R1=0.052), have been determined by single crystal x-ray diffraction technique in the cubic space group Pm3^m at 21 ℃. In all structures, each unit cell contained three M+ ions all located at one crystallographically distinct position on 8-rings. Rb+ ions are 3.12 and 3.21 Å away respectively from O(1) and O(2) oxygens, about 0.40 Å away from the centers of the 8-rings, and K+ ions are 2.87 and 2.81 Å apart from the corresponding oxygens. These distances are the shortest ones among those previously found for the corresoponding ones. Eight 6-rings per unit cell are occupied by eight Na+ ions, each with a distance of 2.31 Å to three O(3) oxygens. The twelfth cation per unit cell is found as Na+ opposite 4-ring in the large cavities of M3Na9-A and assumed to be H+ for M3Na8H-A. With these noble non-framework cationic arrangements, larger M+ ions preferably on all larger 8-rings and the compact Na+ ions on all 6-rings, the bond angles in the 8-rings of M3-A, 145.1 and 161.0 respectively for (Si,Al)-O(1)-(Si,Al) and (Si,Al)-O(2)-(Si,Al), turned out to be remarkably stable and smaller, by more than 12 to 17°, than the corresponding angles found in the crystal structures of zeolites A with high concentration of M+ ions. It is to achieve these remarkably relaxed 8-rings, the main windows for the passage of gas molecules, with simultaneously maximized cavity volumes that M3-A have been selected as one of the efficient zeolite A systems for gas encapsulation.

• Journal of Environmental Science International
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• v.12 no.9
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• pp.997-1004
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• 2003

The objective of this research was to test whether, under controlled laboratory conditions, hybrid SNCR/SCR process improves N $O_{x}$ removal efficiency in comparison with the SNCR only. The hybrid process is a combination of a redesigned existing SNCR with a new downstream SCR. N $O_{x}$ reduction experiments using a hybrid SNCR/SCR process have been conducted in simple NO/N $H_3$/ $O_2$ gas mixtures. Total gas flow rate was kept constant 4 liter/min throughout the SNCR and SCR reactors, where initial N $O_{x}$ concentration was 500 ppm in the presence of 5% or 15% $O_2$. Commercial catalysts, $V_2$ $O_{5}$ -W $O_3$-S $O_4$/Ti $O_2$, were used for SCR N $O_{x}$ reduction. The residence time and space velocity were around 1.67 seconds and 2,400 $h^{-1}$ or 6000 $h^{-1}$ in SNCR and SCR reactors, respectively. N $O_{x}$ reduction of the hybrid system was always higher than could be achieved by SNCR alone at a given value of N $H_{3SLIP}$. Optimization of the hybrid system performance requires maximizing N $O_{x}$ removal in the SNCR process. An analysis based on the hybrid system performance in this lab-scale work indicates that a equipment with N $O_{xi}$ =500 ppm will achieve a total N $O_{x}$ removal of about 90 percent with N $H_{3SLIP}$ $\leq$ 5 ppm only if the SNCR N $O_{x}$ reduction is at least 60 percent. A hybrid SNCR/SCR process has shown about 26∼37% more N $O_{x}$ reduction than a SNCR unit process in which a lower temperature of 85$0^{\circ}C$ turned out to be more effective.be more effective.

• The Journal of the Korean life insurance medical association
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• v.4 no.1
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• pp.101-109
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• 1987

The present study was undertaken to establish the standard body weight by height in Korean adults by using the actually measured heights and weights of a total of 5,496 insured persons who were examined medically at the Honam Medical Room of Dong Bang Life Insurance Company, Ltd. from January, 1983 to January, 1986. The results were as follows: 1. The linear regression equations to establish the standard body weight of Korean adults were as follows: In male, for $18{\sim}19$ age group, $y=7.272{\times}10^{-6}{\times}x^3+23.560$ for $20{\sim}29$ age group, $y=8.187{\times}10^{-6}{\times}x^3+22.031$ for $30{\sim}39$ age group, $y=8.627{\times}10^{-6}{\times}x^3+23.169$ for $40{\sim}49$ age group, $y=9.561{\times}10^{-6}{\times}x^3+20.994$ and for $50{\sim}59$ age group, $y=8.604{\times}10^{-6}{\times}x^3+23.801$ In female, for $18{\sim}19$ age group, $y=8.252{\times}10^{-6}{\times}x^3+18.920$ for $20{\sim}29$ age group, $y=7.715{\times}10^{-6}{\times}x^3+22.409$ for $30{\sim}39$ age group, $y=8.808{\times}10^{-6}{\times}x^3+21.439$ for $40{\sim}49$ age group, $y=9.691{\times}10^{-6}{\times}x^3+21.940$ and for $50{\sim}59$ age group, $y=12.500{\times}10^{-6}{\times}x^3+11.031$ 2. The standard age, height, and weight tables by author were presented with the aid of linear regression equations. 3. The values of standard body weight by height established by author reveal to be a little higher than those of other Korean reports through all age groups of both sexes, and reveal to be considerably similar, compared with those of the reports in Japan for fourth and sixth decade of female group.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2545-2550
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• 2009

The purpose of this study was to examine the oral health care and oral health awareness of some laborers. Out of them, 220 workers were selected from K motor company in Hwaseong, and the other 180 workers were selected from D automobile company in Bupyeong. The findings of the study were as follows: As for daily toothbrushing frequency, the largest number of the laborers investigated(44.0%) brushed their teeth three times a day. Smoking made a significant difference to that($x^2$=19.00, p<.01). Concerning the use of oral hygiene supplies, 41.3 percent put oral hygiene supplies to use. There was a significant difference in that aspect according to gender($x^2$=9.20, p<.01). Regarding scaling experience, the largest group(37.3%) had their teeth scaled twice or more, and their scaling experience significantly varied with gender($x^2$=8.60, p<.05), age($x^2$=20.07, p<.01), academic credential($x^2$=11.88, p<.01) and the presence or absence of systemic diseases($x^2$=8.19, p<.05). In relation to oral diseases, the greatest group(27.8%) had dental caries. By gender, the female workers had more dental caries or the more swollen gums than the males, and the gap between the two was significant($x^2$=13.65, p<.05).