• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.1
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• pp.42-48
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• 1998

Synthesis of PLT($Pb_{1-X}La_{2X/3}TiO_3$, x=0.1~0.3) powders was carried out by hydrothermal method. Optimal conditions for synthesis were $250^{\circ}C$ of reaction temperature, 8M-KOH solution of hydrothermal solvent and 12 hrs reaction time, and the monolithic $Pb_{1-X}La_{2X/3}TiO_3$ particles were obtained with the composition of x$\leq$0.2. The tetragonality(c/a) and the phase transition temperature were decreased by the increment of the $La_2O_3$ contents in PLT solid solutions, and the Curie temperature of the $Pb_{1-X}La_{2X/3}TiO_3$(x=0.2) was $400^{\circ}C$. The shape of the synthesized particles were nearly spherical and the size was in the 20~200 nm range.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.1
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• pp.87-95
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• 2002

This study was carried out to investigate the load of soil layers affected by soil depth in artificial soil alone or in blends with Loam with various ratio. The artificial soils were perlite large grain, perlite small grain, and perlite small grains blended with Loam (sand 46%, silt 40%, clay 14%) at a ratio of 8:2, 6:4, 5:5 (v/v). The soil layers were divided into a planting layer and a well-drained layer, then the weight of each layer in the air-dried state and in the field capacity were determined. The data were subjected to correlation analysis, regression analysis, and paired samples t-test. The summarized results are as follows; 1) In the air-dried state, the regression equations of the well-drained layer weight(kg/m2) in perlite large grain, planting layer weight in perlite small grain, planting layer weight in perlite small grain biended with loam(8:2, v/v), perlite small grain blended with loam(6:4, v/v), and perlite small grain blended with loam(5:5, v/v) were; 1.65824*X+0.026, 1.52292*X-0.052, 3.21468*X+0.515, 6.17549*X+ 0.083, and 6.02100*X + 33.133, respectively, where X is soil depth measured in Centimeters. 2) In the field capacity, the regression equations of the well-drained layer weight(kg/m2) in perlite large grain, planting layer weight in perlite small grain, planting layer weight in perlite small grain blended with loam(8:2, v/v), perlite small grain blended with loam(6:4, v/v), and perlite small grain blended with loam(5:5, v/v) were 5.055*X - 2.006, 7.073*X + 100.008, 8.092*X + 116.676, 10.766*X + 100.112, and 10.974*X + 124.423, respectively, where X is the soil depth measured in Centimeters. 3) All of the equations mentioned above were statistically reliable and therefore easily applicable in practical business affairs.

• Journal of the Korean Wood Science and Technology
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• v.8 no.1
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• pp.22-27
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• 1980

Quantitative assessment of edge blunting of saw-teeth was carried out by TALYSURF. 1. Using the following equation, the real shape of a saw-tooth can be traced on the graph of TALYSURF. ${\frac{{\Delta}h}{h}}={\frac{V{\Delta}_x}{V_x}}$ {${\Delta}h$: vertical distance of stylus h: vertical distance in chart $V{\Delta}_x$: Velocity of stylus $V_x$: velocity of chart} 2. As shown on Fig 2, the error from stylus itself can be calculated by following equation. i) 13.8${\mu}{\leqq}$x<20.4${\mu}$ y=-0.2246x+4.59${\mu}$ ii) 0${\leqq}$x<13.8${\mu}$ y=${\sqrt{(-18{\mu})^2-x^2}}-1.42x+32.7{\mu}}$ 3. The relationship between profile of saw-tooth and error from stylus itself can be calculated by following equation. $E(%)=\frac{f(r){\times}{\frac{4}{18{\mu}}}}{f(R){\times}{\frac{R}{18.5{\mu}}}-f(r){\times}{\frac{r}{18{\mu}}}}{\times}100$ {E(%)${\frac{error\;of\;stylus}{dullness\;of\;saw\;tooth}}{\times}100$ r: radius of stylus tip R: radius of tip which is drawn in graph of talysurf f(r) : error of stylus f(R) : dullness of tip which is drawn in graph of talysurf} 4. The graph of maximum error and profile of saw-tooth was parabola.

• Radiation Oncology Journal
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• v.20 no.3
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• pp.246-252
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• 2002

Purpose : It has been recognized that interaction of the Fas : Fas ligand plays an important role in radiation-induced apoptosis. The purpose of this study was to investigate the role of Fas mutation in radiation-induced apoptosis in vivo. Materials and Method : Mice with mutations in Fas, $MRL/Mpj-Fas^{Ipr}$, and its normal control, MRL/Mpj, were used in this study. Eight-week old male mice were given whole body radiation. After irradiation, the mice were killed and their spleens were collected at different time intervals. Tissue samples were stained with hematoxylin-eosin and the numbers of apoptotic cells were scored. Regulating molecules of apoptosis including p53, Bcl-2, Bax, $Bcl-X_L,\;and\;Bcl-X_S$ were also analyzed by Western blotting. Results : At 25 Gy irradiation, the level of apoptosis reached the peak value at 8 hr after radiation and recovered to the normal value at 24 hr after radiation in MRL/Mpj mice. In contrast, the peak apoptosis level appeared at 4 hr after radiation in $MRL/Mpj-Fas^{Ipr}$. At 8 hr after radiation, the levels of apoptosis in MRL/Mpj mice and $MRL/Mpj-Fas^{Ipr}$ mice were $52.3{\pm}7.8\%\;and\;8.0{\pm}8.6\%$, respectively (p<0.05). The expression of apoptosis regulating molecules, p53, $Bcl-X_L\;and\;Bcl-X_S$, increased in MRL/Mpj mice in response to radiation; p53 with a peak level of 3-fold at 8 h, $Bcl-X_L$ with a peak level of 3.3-fold at 12 h, and $Bcl-X_S$ with a peak level of 3-fold at 12 h after 25 Gy radiation. Bcl-2 and Bax did not show significant change in MRL/Mpj mice. However in $MRL/Mpj-Fas^{Ipr}$ mice, the expression levels of p53, Bcl-2, Bax, $BCl-X_L\;and\;BCl-X_S$ showed no significant change. Conclusion : The level of radiation-induced apoptosis was lower in Fas mutated mice, Ipr, than in control mice. This seemed to be related to the lack of radiation-induced p53 activation in the Ipr mice. This result suggests that Fas plays an important role in radiation-induced apoptosis in vivo.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.1
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• pp.32-40
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• 2024

The aim of this research was to apply a method designed to derive the factors influencing total ammonia removal when operating an additional pretreatment system at Aquaponics. The Box-Behnken method, among response surface analysis methods was used to characterize and determine the optimal nitrification conditions when operating the pretreatment system. Among the mathematically and statistically calculated prediction equations, the total ammonia nitrogen concentration Y1 measured on day 8 was derived as Y₁=-195.8+2.23X₁+42.9X₂+47.5X₃+0.1856X₁²-1.380X₁X₂-1.770X₁X₃, and the time taken to reach the maximum total ammonia nitrogen concentration during the experiment period was derived as Y₂=271-5.04X₁+60.5X₂-64.8X₃+0.1654X₁²+6.54X₃²-0.600X₁X₃-9.00X₂X₃. The coefficients of determination of the regression models of Y₁ and Y₂ were 93.99% and 94.46%, respectively. The modified coefficients of determination were also high, at 89.48% and 88.91%, respectively. The prediction coefficients of determination of Y₁ and Y₂, were 70.68% and 62.11%, respectively, which was relatively lower than that of Y1, but still indicated a reliable prediction performance.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.1 s.12
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• pp.38-46
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• 2007

In this paper an X-band low phase noise HBT oscillator using a planar type MMIC resonator is designed. The chip area of the proposed resonator shows a quarter of the conventional hair-pin resonator using distributed transmission lines. The measurement results show oscillation frequency of 8.295 GHz, the power output of 4.8 dBm, and phase noise characteristic of -106.8 dBc/Hz and -121.7 dBc/Hz at 100 kHz and 1 MHz offset frequencies respectively.

• Journal of the Korean Electrochemical Society
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• v.1 no.1
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• pp.1-7
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• 1998

For the purpose of finding new cathode materials for medium-temperature $(700\~800^{\circ}C)$ solid oxide fuel cells, $Gd_{0.8}Ca_{0.2}Co_{1-x}Fe_xO_3,\;(x=0.0\~0.5)$ are prepared, and their thermal stability and conductivity characteristics are investigated. Also, the cathodic activities are measured after the cathode layer being attached on CGO (cerium-gadolinium oxide) electrolyte disk. The X-ray analyses indicate that the materials prepared by calcining the citrate-gels at $800^{\circ}C$ have the orthorhombic perovskite structure without discernible impurities. The thermal stability of the undoped Co perovskite is so poor that it is decomposed to the individual binary oxide even at $1300^{\circ}C$. But the partially Fe-doped cobaltates exhibit a better thermal stability to retain their structural integrity up to $1400^{\circ}C$. The observation whereby both the undoped and Fe-doped cobaltates melt at ca. $1300^{\circ}C$ leads us to perform the electrode adhesion at <$1300^{\circ}C$. The cathodic activity of $Gd_{0.8}Ca_{0.2}Co_{1-x}Fe_xO_3,\;(x=0.0\~0.5)$, electrodes is superior to $La_{0.9}Sr_{0.1}MnO_3$, among the samples of $x=0.0\~0.5$, the x=0.2 cathode shows the best activity for the oxygen reduction reaction. It is likely that the Fe-doping provides a better thermal stability to the materials but in turn imparts an inferior cathodic activity, such that the optimum trade-off is made at x=0.2 between the two factors. The total electrical conductivity and ion conductivity of $Gd_{0.8}Ca_{0.2}Co_{1-x}Fe_xO_3$, are measured to be 51 S/cm and $6.0\times10^{-4}S/cm\;at\;800^{\circ}C$, respectively. The conductivity values illustrate that the materials are a mixed conductor and the reaction sites can be expanded to the overall electrode surface, thereby providing a better cathodic activity than $La_{0.9}Sr_{0.1}MnO_3$.

• Journal of Magnetics
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• v.7 no.2
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• pp.25-28
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• 2002

Slowly cooled $Cu_xFe_{3-x}O_4$ ($\chi$=0.1, 0.2) have been investigated over a temperature range from 82 to 700 K using the M$\ddot{o}$ssbauer technique. X-ray diffraction shows that these have a single-phase cubic spinel structure of lattice parameters $\alpha$=8.396 and 8.398${\AA}$, respectively. Since Cu ions prefer B (octahedral) sites to A (tetrahedral) sites, the ionic distribution is $(Fe)_A[Fe_{2-x}Cu_x]_BO_4$. M$\ddot{o}$ssbauer spectra consisted of two sets of 6-line pattern from. A site in ferric state and B site in ferrous-ferric state. Intensity ratio of B to A subspectra is 1.0 at 82 K and increases to 2.0 at 700 K with increasing temperature. After annealing the samples under vacuum at $450^circ{C}$ for a half hour, x-ray diffraction patterns have the peaks of magnetite- and hematite-phase. Lattice constants of magnetite-phase are 8.395 and 8.392 ${\AA}$ smaller than 8.396 and 8.398 ${\AA}$ before annealing, respectively. M$\ddot{o}$ssbauer spectra reveal the conventional magnetite pattern with the additional hematite pattern. Intensity ratios of B to A subspectra fur magnetite-phase become 1.9-2.0 over all temperature ranges and Cu ions are distributed over A and B sites randomly. Ratios of hematite to total intensity in M$\ddot{o}$ssbauer spectra for $\chi$= 0.1 and $\chi$= 0.2 are 10 and 21%, respectively. These hematite ratios may be due to annealing under vacuum at $450^circ{C}$, which transforms $Cu^{2+}$ ionic states into $Cu^{1+}$. Verwey temperatures far $\chi$= 0.1 and $\chi$= 0.2 are $123\pm2$ K and $128\pm2$ K.

• 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).

• The Journal of Natural Sciences
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• v.14 no.1
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• pp.25-37
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• 2004

T7 RNA polymerase also recognize intrinsic, hairpin-independent termination signal, a conserved 7-base pair sequence (ATCTGTT in the non-template stand) and U-rich sequence downstream of it. These intrinsic, hairpin-independent termination signal were commonly found in PTH and CJ termination sequences. There are two types of mutant T7 RNA polymerases recognizing sensitively(X3, X19, BG8) of insensitively (R173C) the intrinsic termination signals. We determined the T7 transcription activities of these mutants. Compared to wild-type, mutants X4, 19 and BG8 show highly reduced transcription activities (8%, 33%, 34%). On the other hand mutant R173C shows comparable transcription activity of wild-type (112%). Also transcription termination efficiencies at the PTH or CJ termination signals were determined by using mutant RNA polymerases. Temination of mutnats X4, X19 and BG8 are increased compared to wild-type. On the other hadn mutant R173C proceeds through PTH and CJ termination signals.