• Journal of Magnetics
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• 제6권2호
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• pp.57-60
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• 2001

Mechanically alloyed $TbCu_7 -type \;Sm_{12.5}Fe_{87.5-x}Ti_x$(x=0, 2.5, 5, 7.5),and their nitrides have been studied systematically by X-ray diffraction, A.C. initial susceptibility, and pulsed magnetization measurement. In this series, the volume expansion by nitriding is 5.6%~7.3%, and the increment of the Curie temperature is in the range of 21$0^{\circ}C$~35$0^{\circ}C$. With increasing Ti content, the remanence decreases linearly due to the substitution of non-magnetic Ti, and the coercivity decreases rapidly from 34.6 kA/cm (43.5 kOe) for $\chi$=0 to 14.3 kA/cm (18 kOe) for $\chi$=7.5. In the $Sm_{12.5}Fe_{87.5-x}Ti_xN_y$ series, the best magnetic properties were obtained from .7Ti7Ny series, the best magnetic properties were obtained from $Sm_{12.5}Fe_{87.5}N_y$($\chi$=0) with $_iH_c$=34.6 kA/cm (43.5 kOe), $B_r=0.75 \;T, \;and (BH)_{max}=113.8 kJ/m^3$(10.9 MGOe).

• 대한지하수환경학회지
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• 제3권1호
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• pp.37-49
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• 1996

이 연구에서는 난지도 매립지와 화성매립지를 연구대상으로하여 주변의 지하수 오염 정도를 파악하고, 오염물질들의 지연작용을 밝히며, 최적 오염지시인자를 도출하고자 하였다. 난지도, 김포, 화성 매립지에서 채취된 침출수에 대하여 현장측정과 실내 화학분석을 실시하여 침출수의 물리화학적 수리화학적 특성들을 파악한 결과 침출수는 높은 온도(31.7-40.1$^{\circ}C$)와 높은 전기전도도(14,650-32,800 $\mu$S/cm), 약 알칼리의 pH(7.58-8.45), 낮은 Eh값(-119.4-20.4 mV)을 특징적으로 보이며, 주성분 이온들로서 $Na^{＋}$, $K^{＋}$, $Ca^{2＋}$, $Mg^{2＋}$, HC $O_3$$^{－}$, C $l^{－}$ 등이, 부성분 이온들로서 Mn, S $r^{2＋}$, $Ba^{2＋}$, L $i^{＋}$, $F_{－}$, B $r^{－}$ 등이 부화되어 있다. 일반폐기물 매립지인 난지도.김포 매립지의 침출수와 산업폐기물 매립지인 화성매립지의 침출수는 S $O_4$$^{2－}$ , Fe 중금속 원소들의 함량으로 구분된다. 지표수와 지하수의 화학분석, Cl 표준화과정, WATEQ4F 분석 등을 종합하여 앞서 연구된 유선망 분석을 바탕으로 오염물질의 거동을 해석하였다. 또한 Contamination Factor를 통하여 최적의 오염지시인자를 도출하였다. 일반페기물 매립지인 난지도 매립지의 경우 K, Na, Ca, Mg, B, Zn, HC $O_3$, Cl, F, Br, TOC 등이 , 산업 폐기 물 매립지인 화성 매립지의 경우 K, Na, Ca, Mg, B, S $O_4$, HC $O_3$, Cl, F, Br, TOC 등이 뚜렷한 대조를 보이는 좋은 오염지시인자이며, 해안 매립지는 TOC가 가장 적합한 오염지시 인자이다.

• 한국미생물·생명공학회지
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• 제17권2호
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• pp.126-130
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• 1989

인삼 saponin 중에서 조성 비율이 가장 큰 ginsenoside R $b_1$을 약효면에서 훨씬 우수한 ginsenoside-Rd로 선택적 전환할 수 있는 전환효소를 Rhizopus japonicus 배양물로부터 순수하게 정제한 후 그 효소학적 특성을 조사하였다. 본 효소는 pH 4.8~5.0, 45$^{\circ}C$에서 그 활성도가 가장 높았으며 pH4~9의 범위에서 안정하였고, pH5.0에서 6$0^{\circ}C$ 열처리할 경우 50% 실활하는데 2시간이 소요되었다. M $n^{++}$, F $e^{++}$에 의해 효소활성이 촉진되었으며 C $u^{++}$, A $g^+$에 의해서는 저해되었다. 효소 저해제중에는 EDTA, o-phenanthroline 등에 의해 저해되기도 했다. 본 효소는 당류중에는 gentiobiose, cellulose만을, glycoside 중에서는 amygdalin, purnasin, salicin 등을 분해할 수 있었으며 ginsenoside R $b_1$, 이외의 다른 ginsenoside는 전혀 분해할 수 없었다. 본 효소의 Km치는 total saponin 기질 및 ginsenoside Rb group saponin 기질은 ginsenoside R $b_1$으로서 5.0mM 이었으며, gentiobiose는 4.8mM, amygdalin은 3.7mM 이었다.

• 천문학회지
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• 제50권3호
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• pp.79-92
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• 2017

We present a BV I optical photometric study of the old open cluster Ruprecht 6 using the data obtained with the SMARTS 1.0 m telescope at the CTIO, Chile. Its color-magnitude diagrams show the clear existence of the main-sequence stars, whose turn-off point is located around $V{\approx}18.45mag$ and $B-V{\approx}0.85mag$. Three red clump (RC) stars are identified at V = 16.00 mag, I = 14.41 mag and B - V = 1.35 mag. From the mean $K_s-band$ magnitude of RC stars ($K_s=12.39{\pm}0.21mag$) in Ruprecht 6 from 2MASS photometry and the known absolute magnitudes of the RC stars ($M_{K_S}=-1.595{\pm}0.025mag$), we obtain the distance modulus to Ruprecht 6 of $(m-M)_0=13.84{\pm}0.21mag$ ($d=5.86{\pm}0.60kpc$). From the ($J-K_s$) and (B - V ) colors of the RC stars, comparison of the (B - V ) and (V - I) colors of the bright stars in Ruprecht 6 with those of the intrinsic colors of dwarf and giant stars, and the PARSEC isochrone fittings, we derive the reddening values of E(B - V ) = 0.42 mag and E(V - I) = 0.60 mag. Using the PARSEC isochrone fittings onto the color-magnitude diagrams, we estimate the age and metallicity to be: $log(t)=9.50{\pm}0.10(t=3.16{\pm}0.82Gyr)$ and $[Fe/H]=-0.42{\pm}0.04dex$. We present the Galactocentric radial metallicity gradient analysis for old (age > 1 Gyr) open clusters of the Dias et al. catalog, which likely follow a single relation of $[Fe/H]=(-0.034{\pm}0.007)R_{GC}+(0.190{\pm}0.080)$ (rms = 0.201) for the whole radial range or a dual relation of $[Fe/H]=(-0.077{\pm}0.017)R_{GC}+(0.609{\pm}0.161)$ (rms = 0.152) and constant ([Fe/H] ~ -0.3 dex) value, inside and outside of RGC ~ 12 kpc, respectively. The metallicity and Galactocentric radius ($13.28{\pm}0.54kpc$) of Ruprecht 6 obtained in this study seem to be consistent with both of the relations.

• 소성∙가공
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• 제20권4호
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• pp.296-302
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• 2011

The objective of this paper is to determine the effect of process parameters on the behavior of a 18Cr-10Mn-$0.44N_2$ nitrogen steel sample deformed by hot rolling. Compression tests were carried out at high temperatures to determine the flow stresses needed for a finite element(FE) analysis. The strain rate, ranging from 0.1 to $1.0s^{-1}$, significantly affected the flow stress at temperatures higher than $1,000^{\circ}C$. Non-isothermal rolling simulations and laboratory rolling tests were performed with plate specimens 14.5mm thick, 135mm wide and 226mm long. A rolling reduction of 15% per pass leading to a cumulative rolling reduction of 60% was determined as optimal. The extension ratio of 176.5% in the length direction was about 30.4 times greater than the extension ratio of 5.8% in the width direction. Isotropic properties for tensile strength, microstructure and grain size were measured after mock-up hot rolling tests. The results from the mockup tests were found to be in good agreement with those of the simulations.

• 한국식품영양과학회지
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• 제7권1호
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• pp.35-39
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• 1978

In order to understand the diets of Gwangju city resident, nutrition survey was carried out through four years from 1974 to 1977. 1. Average intake of nutritional elements for an adult per day was 580. 25gr in 1974, 583.62gr in 1975, 599.13gr in 1976, and 597.72gr in 1977. 2. Average calorie distribution of the nutritional elements per adult per day was 13.51% protein, 4.70% fat and 81.08% carbohydrate in 1974; 11.6% protein, 7.1% fat and 81.3% carbohydrate in 1975; 15.0% protein, 4.9% fat and 80.1 % carbohydrate in 1976; 13.79% protein, 4.3% fat, and 82% carbohydrate in 1977. 3. The ratio of the animal protein to total protein consumed was 20.01% in 1974, 25.89% in 1975, 26.01% in 1976, and 29.38% in 1977. 4. In aspect of calorie, taken-in calorie was 2456.91 cal in 1974, 2515.10 cal in 1975, 2544.58 cal in 1976, and 2519.08 cal in 1977. However most of calorie were lower than the R.D.A. (3000cal). 5. The amount of ingested protein was 78.18 gr in 1974, 87.61 gr in 1975, 89,93 gr in 1976, and 81.65gr in 1977. The amount was higher than the R.D.A. (80gr) except 1974’s protein amount. 6. As for fat consumption, it was 27.18 gr in 1974, 40.96gr in 1975, 29.61gr in 1976, and 25.64gr in 1977. But these values were much lower than the R.D.A. (40gr) except for 1975’s. 7. In aspect of the minerals (Fe, Ca), intake of Ca was 462.34mg in 1974, 400.07 mg in 1975, 488.14 mg in 1976 and 440.95mg in 1977. The consumption of Ca was lower than the R.D.A. (600mg). Fe was 10.27mg in 1974, 8.54mg in 1975, 11.36mg in 1976 and 20.84mg in 1977. Most of them were higher than the R.D.A. (10mg) except 1975. 8. It was found that thiamine and riboflavin were ingested slightly higher than the R.D.A. (1.4mg, vit. $B_1$, 1.6mg, vit. $B_2$). The amount of niacin and ascorbic acid were also higher than the R.D.A. except 15.41mg of niacin in 1975.

• 미생물학회지
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• 제6권3호
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• pp.87-91
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• 1968

To research the characteristics of cellulose produced from one strains of Rhizopus(R-B 14) when it acts on the carboxyl methyl cellulose, this experiment was carried out in crude purified cellulose. The results obtained were as follows: 1. The optimum pH of cellulose was from 4. 5 to 5 .5 and the range of its stability to the pH was considerably extensive and it was from 4 to 7. 2. The optimum temperature of cellulose was $50^{\circ}C$ and the activity of it was instantly inactivated at $70^{\circ}C$. 3. The inhibition of the metal ions to the activity of cellulose was as follows; $Hg^{++}$ > $Ag^+$ +/ > $Fe^{+++}$ > $Pb^{++}$. But the activity of cellulose was not affected at all by $Na^+$, $K^+$ and $Mg^{++}$.

• 한국자기학회지
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• 제7권1호
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• pp.13-18
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• 1997

기본 조성 N $i_{0.18}$Z $n_{0.68}$C $u_{0.14}$F $e_{2}$ $O_{4}$와 N $i_{0.14}$Z $n_{0.64}$C $u_{0.22}$F $e_{2}$ $O_{4}$ 및 N $i_{0.24}$Z $n_{0.64}$C $u_{0.12}$F $e_{2}$ $O_{4}$에 입계의 고저항층을 형성하고 소결을 촉진시키기 위해서 0.1 mol %의 Ca $Co_{3}$와 입자의 성장을 촉진시키고 높은 투자율을 얻을 목적으로 $V_{2}$ $O_{5}$를 0.04 mol% 첨가하였다. 이들 원료들을 혼합한 후 950 .deg. C에서 3시간 하소 과정을 거친후 ball mill해서 toroid 시편을 만들고 1030 .deg. C, 1050 .deg. C 및 1070 .deg. C 에서 2시간 동안 공기중에서 소결 시켰다. Raw material의 조성비 변화 및 소결 온도 변화에 따른 여러 가지 물리적 특성들을 조사하였다. X-선 회절 분석 결과 이들 시편들이 spinel 구조를 이루고 있음을 확인하였고 금속현미경으로 측정한 결정 입자의 크기는 6 .mu. m ~ 16 .mu. m 이었다. 초투자율, 자기 유도는 소결 온도가 1030 .deg. C에서 1050 .deg. C로 증가함에 따라 증가하였고 Q factor와 보자력은 감소하였다. 보자력과 큐리온도는 각각 0.17 Oe 및 220 .deg. C 근처로 모든 시편들에서 거의 비슷하였다. 본 시편의 사용 주파수 범위는 0.4 ~ 20 MHz로 확인되었으며, 소결 온도 1050 .deg.C와 기본 조성 N $i_{0.14}$Z $n_{0.64}$C $u_{0.22}$F $e_{2}$ $O_{4}$ 에서 다른 사람들 보다 더욱 더 우수한 자기유도값(B, $B_{m}$ )을 얻을 수 있었다.

• 한국자기학회지
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• 제14권1호
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• pp.38-44
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• 2004

초거대 자기저항 물질인 페롭스카이트 구조의 망간 산화물 L $a_{0.67}$B $a_{0.33}$M $n_{1-x}$ F $e_{x}$ $O_3$(이하 LBMFO)에 대하여 에탄올을 용매로 한 졸겔법을 이용하여 미량의 철을 치환한 단일상의 LBMFO산화물 분말을 제조하였다. 결정학적 및 자기적 성질을 x선 회절법, 시료진동형 자화율 측정기(VSM), 중성자 회절 실험, 러더포드 후방 산란법, Mossbauer 분광법 및 자기저항 측정을 통하여 연구하였다. X-선 및 중성자 회절실험 분석 결과 결정학적 구조는 Pnma의 공간구조를 갖는 orthorhombic구조로 분석되었다. 미량의 철이 치환됨에 따라 격자상수 $a_{0}$ , $c_{0}$ 는 증가하며, $b_{0}$ 는 감소하는 경향을 보였다. VSM측정결과 포화 자화값과 보자력은 철의 치환량이 증가함에 따라서 각각 감소하는 경향을 보였다. 큐리(Curie)온도는 철의 치환량이 증가함에 따라서 360 K에서 점차 감소하는 경향성을 나타내었다. 철을 1 % 치환한 경우 1T 인가자장 하에 최대자기저항변화의 비($\Delta$$\rho$/$\rho$$_{H}$)는 281 K에서 9.5%였으며, 금속-반도체 전이 온도는 253 K로 관측되었다. Mossbauer 스펙트럼 분석결과 15 K에서 날카로운 Lorentzian 12 line(2 set)의 공명 흡수선으로 측정되었다. 이성질체 이동 값으로부터 미량 치환된 $^{57}$ Fe이온의 전자 상태는 +3가 임을 알 수 있었다.는 +3가 임을 알 수 있었다.

• 대한핵의학회지
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• 제1권1호
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• pp.1-19
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• 1967

The effects of X-ray irradiation and the thyroid gland on the erythropoietic system were studied in the white male rabbits. The total body irradiation was done in doses of 250 r and 500 r to each of 5 rabbits for 10days. The factors were 220KV, 10mA, FLI/4 Cu+1 mmAI(HVL:2.0 mm Cu) 50 cm F.S.D. The thyroid dysfunction was experimentally induced, by giving 2mg of thyroid tablets per kg body weight for 15 days in 5 rabbits for hyperthyroidism and by giving 1.5 mC of $^{131}I$ per kg body weight in another 5 rabbits for hypothyroidism. Fourteen healthy rabbits were used as control. The hematologic changes and ferrokinetic data obtained from $^{59}Fe$ and apparent half survival of the red blood cells obtained from $^{51}Cr$ were compared. Following were the results: A. X-ray irradiated group; 1. There were no significant changes in hematologic findings except for leucopenia. A slight decrease of red blood cells was observed in 500 r irradiated animals. 2. The decreases in the iron turnover rates of the plasma and red blood cells as well as in the red cell renewal rate were found in both groups. A :significant decrease of the red cell iron utilization rate was observed in the 500 r irradiated animals. 3. The apparent half survival times of the red blood cells were slightly, in the 250 r ($12.1{\pm}0.80$ days), and markedly shortened in the 500 r irradiated animals ($9.8{\pm}1.38$ days), the normal being $14.0{\pm}1.6$ days. 4. It appears, therefore, that the anemia caused by X-ray irradiation is due to the inhibition of hemopoietic function and the excess destruction of the red blood cells. B. Thyroid dysfunction group; 1. The slight increases of the red blood cell count and circulating blood volume with the normal serum iron level were observed in the hyperthyroid group, while the decreases of the red and white blood cell counts, hemoglobin and hematocrit values with a marked decrease of the serum iron level in the hypothyroid group. 2. A marked decrease of the plasma iron disappearance rate with increases of plasma iron turnover, red cell iron utilization and red cell iron turnover were observed in the hyperthyroid group, while the marked delay and decreases in the hypothyroid group. 3. The apparent half survival times of the red blood cells were almost the same with the control in the hyperthyroid group, ($14.0{\pm}1.58$ while a marked shortening in the hypothyroid group $10.6{\pm}0.30$. 4. It was reconfirmed that the thyroid hormones bear a close relationship with the erythropoietic system, namely, the latter is stimulated by the former. The lack of the thyroid hormones thus induces the bone marrow depression leading to anemia the major cause of which, therefore, is not hemolysis.