• Journal of the Korean Magnetics Society
• /
• v.5 no.1
• /
• pp.64-70
• /
• 1995

The authors have studied crystallographic and magrletic properties of $NdFe_{10.7}TiM_{0.3}(M=B,\;Ti)$ by X-ray diffraction, VSM magnetometer, and Mossbauer spectrometer. The Alloys were prepared by arc-melting under argon atmosphere. The $NdFe_{10.7}TiM_{0.3}$ has pure single phase, whereas the $NdFe_{10.7}Ti_{1.3}$ contains some $\alpha-Fe$, from powder X-ray diffractometry. The $NdFe_{10.7}TiM_{0.3}$ has the $ThMn_{12}$-type tetragonal structure with $a_{0}=8.587\;{\AA}\;and\;c_{0}=4.788\;{\AA}$. The Curie temperature ($T_c$) is $570{\pm}3\;K$ from $M\"{o}ssbauer$ spectroscopy performed at various temperatures ranging from 13 to 770 K. Each spectrum of below $T_c$ was fitted with five subspectra of Fe sites in the structure ($8i_{1},\;8i_{2},\;8j_{1},\;8j_{2}\;and\;8f$). The area fraction of the subspectra at room temperature are 16.4, 8.2, 14.8, 21.3 and 39.3 %, respectively. Magenetic hyperfine fields for the Fe sites decrease in the order, $H_{hf}(8i)>H_{hf}(8j)>H_{hf}(8f)$.

• Journal of Sensor Science and Technology
• /
• v.3 no.2
• /
• pp.65-73
• /
• 1994

TO:F($SnO_{2}:F$) thin films were prepared by RF magnetron sputtering system. The dependence of their structural, electrical, and optical properties on deposition conditions such as substrate temperature, working pressure and power was studied. The optimum conditions of TO:F thin film are $SnF_{2}$ content of 15wt.% in target, RF power of 150W, substrate temperature of $150^{\circ}C$ and working pressure of 2mmTr. The resistivity and transmittance at 550nm in visible spectrum of the TO:F film deposited at optimum condition are $9{\times}10^{-4}{\Omega}{\cdot}cm$ and above 85%, respectively. For the films deposited from the target without $SnF_{2}$ and with 15wt.% $SnF_{2}$, the optical bandgaps calculated from the transmittance curves are 3.84 and 3.9eV, respectively. X-ray diffraction patterns showed that TO and TO:F films had tetragonal rutile structure with (101), (200) direction.

• Advances in Energy Research
• /
• v.2 no.2
• /
• pp.97-104
• /
• 2014

A co-spray deposition technique has been developed to bypass a fundamental limitation in the conventional spray deposition technique, i.e., the deposition of metal oxides from incompatible precursors in the starting solution. With this technique, ZnO films codoped with F and Al have been successfully synthesized, in which F is incompatible with Al. Two starting solutions were prepared and co-sprayed through two separate spray heads. One solution contained only the F precursor, $NH_4F$. The second solution contained the Zn and Al precursors, $Zn(O_2CCH_3)_2$ and $AlCl_3$. The deposition was carried out at $500^{\circ}C$ on soda-lime glass in air. A minimum sheet resistance, $55.4{\Omega}/{\square}$, was obtained for Al and F codoped ZnO films after vacuum annealing at $400^{\circ}C$, which was lower than singly-doped ZnO with either Al or F. The transmittance for the codoped ZnO samples was above 90% in the visible range. This co-spray deposition technique provides a simple and cost-effective way to synthesize metal oxides from incompatible precursors with improved properties for photovoltaic applications.

• Applied Biological Chemistry
• /
• v.49 no.1
• /
• pp.25-29
• /
• 2006

This study was carried out to isolate the possible anti-tumor promoters from the citrus peel (Citrus natsudaidai Hayata). We fractionated the cold-pressed oil of citrus peel by column chromatography, HPLC and TLC. The analysis on column chromate-graphy yielded seven peaks $(F-I{\sim}F-VII)$, all of which showed single spot on TLC analysis ($R_f$ for $F-I{\sim}VIII$; 0.31, 0.13, 0.13, 0.78, 0.79, 0.69 and 0.84). Among the seven fractions, three fractions (F-I, -II and F-IV) were re-analyzed on HPLC, also showing single peak except for one fraction (F-IV) which was divided two peaks. The retention times $(R_f)$ of F-I and F-II was 3 min. and 2.5 min., respectively, but these of two peaks from F-IV were 2 min. and 4.5 min., respectively. Since the area of the latter peak (4.5 min.) was very smaller than that of the former one (2 min.), it is considered that the latter one did not appear on TLC analysis. The inhibitory effect on tumor promoter 12-O-tetradecanoylphorbol-13-acetate(TPA)-induced Epstein-Barr virus activation in Raji cells was tested for the seven fraction obtained. It decreased in order of F-VI (82.3+1.3%) > F-I (80.4+1.6%) > F-II (77.2+0.9%) > F-III (75.0+1.2%) > F-IV (74.1=1.0%) > F-V (71.0+1.1%) > F-VII (70.2+1.2%). These results imply that some constiuents contained in citrus peels have the inhibitory activity of TPA-induced tumor promotion.

• Korean Journal of Materials Research
• /
• v.8 no.9
• /
• pp.825-830
• /
• 1998

자화된 유도결합형 C4F8 플라즈마로 SiO2를 건식식각시 실리콘 표면에 발생하는 손상과 오염에 대하여 연구하였다. 오염의 분석을 위해서 XPS, SIMS, TEM을 사용하였으며, 손상정도를 측정하기 위해서 HRTEM과 Schottky-diode 구성을 통한 I-V특성 측정을 사용하였다. 유도 결합형 C4F8 플라스마에 0에서 18Gauss까지의 자장이 가해짐에 따라서 실리콘 표면에 생기는 잔류막의 두께가 SiO2식각속도와 선택비의 증가와 함께 증가하였으며, XPS를 통하여 그 조성이 fluorine-rich에서 carbon-rich 한 상태로 변화함을 알 수 있었다. 자장을 가하지 않는 상태에서는 표면에서 $40\AA$부근까지 고밀도의 손상층이 관찰되었으나, 자장을 가함에 따라서 노출된 손상층의 깊이는 깊어지나 그 밀도는 줄어들음을 HRTEM을 통하여 관찰 할 수 있었다. Schottky-diode를 통한 I-V특성곡선의 분석으로 자장이 증가함에 따라서 전기적인 손상이 감소함을 알 수 있었다.

• Ocean and Polar Research
• /
• v.38 no.1
• /
• pp.59-70
• /
• 2016

Establishing the strategic plans to foster the oceans and fisheries (O&F) industry as an engine for national sustainable economic growth has become an important task for developing countries as well as developed countries. The first step to do so is to identify O&F industry and analyze its economic effects. Therefore, the prime purposes of the paper are two-fold. The first is to identify O&F industry and estimate its market size using 2012 Input-Output (I-O) table published by the Bank of Korea. The second purpose is to obtain some quantitative information on production-inducing effect, value-added creation effect, and employment-inducing effect of the O&F industry. To this end, we apply an IO analysis using exogenous specification of the O&F industry. The results show that the O&F industry covers 4.1% and 3.0% of national output and gross domestic product, respectively. Moreover, we found that 1.0 won of production or investment in the O&F industry induces 1.7363 won of production and 0.4759 won of value-added in the national economy. One billion won of production or investment in the O&F industry touches off 7.5569 persons of employment. This information can be utilized in the O&F industry-related policy-making.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.11 no.7
• /
• pp.569-573
• /
• 2001

An approximate representation of discrete functions {f$_{i,j}\mid$｜i, j=-1, 0, 1, …, N+1}in two variables by a fuzzy system is described. We use the cubic B-splines as fuzzy sets for the input fuzzification and spike functions as the output fuzzy sets. The ordinal number of f$_{i,j}$ in the sorted list is taken to be the out put fuzzy set number in the (i, j) th entry of the fuzzy rule table. We show that the fuzzy system is an exact representation of the cubic spline function s(x, y)=$\sum_{N+1}^{{i,j}=-1}f_{i,j}B_i(x)B_j(y)$ and that the approximation error S(x, y)-f(x, y) is surprisingly O($h^2$) when f(x, y) is three times continuously differentiable. We prove that when f(x, y) is a gray scale image, then the fuzzy system is a smoothed representation of the image and the original image can be recovered exactly from its fuzzy system representation when it is a digitized image.e.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.28 no.7
• /
• pp.419-423
• /
• 2015

Sintering, microstructure, thermal conductivity and microwave dielectric properties of xLiF-(1-x)MgO ceramics (x=0.03~0.10 mol) were investigated. The high density was obtained in the specimens of $x{\geq}0.06$, i.e., 0.04 LiF-0.96 MgO in mol, whereas the amount of 0.03 mol LiF was insufficient to densify. From the result that the contact flattening in the sintered specimen was observed, the densification occurred through the liquid-phase sintering. The specimen of x=0.06 showed the highest room-temperature thermal conductivity. Relative density, thermal conductivity, dielectric constant, and quality factor ($Q{\times}f$) of the specimen for x=0.06 sintered at $900^{\circ}C$ for 4 h were 97.8%, $39.2Wm^{-1}K^{-1}$, 9.45, and 14,671 GHz, respectively.

• The Bulletin of The Korean Astronomical Society
• /
• v.40 no.1
• /
• pp.80.1-80.1
• /
• 2015

We present a study of outflows on 24 embedded young stellar objects selected from the source list of the Dust, Ice, and Gas in Time (DIGIT) Herschel key program. To study the relation between the CO outflows observed in low-J transitions and the properties of protostars more consistently with a homogeneous data set, we mapped the CO outflows of the selected targets in the J = 1-0 and J = 2-1 lines with two Korean telescopes (SRAO and TRAO). We compare CO outflow force ($F_{CO}$) with the bolometric luminosity, ($L_{bol}$) bolometric temperature, and the FIR molecular line luminosities of CO, $H_2O$, OH, and [O I] detected by the Herschel-PACS observations. We find that $F_{CO}$ of J = 1-0 is greater than that of 2-1 by a factor of ~ 2. The well known correlation between $F_{CO\;2-1}$ and $L_{bol}$ is not very evident in our sample as a whole, but they show a rather strong correlation when IRAM 04191+1522 is excluded. IRAM 04191+1522 has relatively high $F_{CO\;2-1}$ in spite of its low $L_{bol}$. This object is a well-known VeLLO, which is believed in the quiescent phase of the episodic mass accretion in the embedded stage. $L_{bol}$ traces a current accretion, but $F_{CO\;2-1}$ traces accretion happened long ago. Therefore, the low-$L_{bol}$ with the high-$F_{CO\;2-1}$ can be explained by the episodic accretion. $F_{CO\;2-1}$ shows little correlation with individual FIR line luminosities of CO, $H_2O$, OH, while [O I] and total FIR line luminosity seem to have correlations with $F_{CO\;2-1}$. This result is interpreted as the accretion energy deposits on species differently depending on shock properties, but the total FIR line luminosity sums the total accretion energy dispersed to different species.

• The Journal of Korean Medicine
• /
• v.27 no.3 s.67
• /
• pp.88-106
• /
• 2006

Objectives: This study was carried out to find the immune responses of the Gami-sopunghwalhyeol-tang $(Ji{\={a}}w{\`{e}}i-sh{\={u}}f{\={e}}nghu{\'{o}}xu{\`{e}}-tang)$ (hereinafter referred to GSHT) to the human fibroblast-like synoviocytes (hFLSs) isolated from patients with rheumatoid arthritis. Methods: Experiments were performed to measure the cytotoxity against hFCs and the production of pro-inflammatory cytokines in hFLSs and the production of NO, ROS. Results: 1. The gene expression of TNF-a, IL-6, IL-8 in hFLSs was effectively reduced at $100{\mu}g/ml$, whereas IL-1 $\beta$ was effectively reduced at 100 and $10{\mu}g/ml$ of GSHT. 2. The gene expression of ICAM-1, MMP-3 in hFLSs was effectively inhibited at 100 and $10{\mu}g/ml$ of GSHT, whereas TIMP-1 was effectively increased at 100 and $10{\mu}g/ml$ of GSHT. 3. The gene expression of NOS-II in hFLSs was effectively inhibited at $100{\mu}g/ml$ of GSHT. 4. The production of NO and ROS in hFLSs was inhibited at 100 and $10{\mu}g/ml$ of GSHT. 5. The proliferation of hFLSs was significantly inhibited at $100{\mu}g/ml$ of GSHT. Conclusions: Comparison of the results for this study showed that Gami-sopunghwalhyeol-tang ($Ji{\={a}}w{\`{e}}i-sh{\={u}}f{\={e}}nghu{\'{o}}xu{\`{e}}-tang$: GSHT) had immunomodulatory effects of suppressing or enhancing.