• Korean Journal of Materials Research
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• v.2 no.4
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• pp.293-297
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• 1992

The magnetic properties of the amorphous Fe/sub 32/Ni/sub 36/Cr/sub 14/P/sub 12/B/sub 6/ has been studied by Mossbauer spectroscopy in the temperature range of 88-400K. The analysis of the spectrum of B8K, the magnetic hyperfine field and quadrupole splitting are found to be 140.5kOe and almost zero, which means that the magnetic hyperfine field is randomly oriented with respect to the principal axes of the electric field gradient, respectively. The values of quadrupole splitting in paramagnetic phase with Tc=280K are independent on the changes of temperature. Debye temperature is found to be about 288k from the analysis of recoilless fraction.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1285-1294
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• 1998

Whey powder, a by-product of milk industry, was utilized to produce biopolymer film with the combination of film matrix supporting material, sodium caseinate. Biopolymer films were prepared from whey powder-sodium caseinate mixtures at several mixing ratios. The effects of pH, plasticizers and cross-linkers on tensile strength (TS) and elongation (E) of films were investigated. The films could be formed by use of whey powder up to 70%. As the whey powder content was increased, TS of the film decreased while E increased. Films containing more than 70% of whey powder could not be formed due to the stickiness of lactose in whey powder. The optimum pH of the film solution was found to be 10. Among the plasticizers tested, sorbitol was found to be the most effective plasticizer while glycerol was inadequate for the film. Tensile strengths of films containing $30{\sim}40%$ whey powder were higher than 10 MPa with relatively high E, when the films were plasticized with 30% (w/w) and 40% sorbitol. TSs of the relatively weak films containing $50{\sim}60%$ whey powders were improved by the addition of small amount of sodium citrate for 30% sorbitol plasticized films, and by the addition of sodium chloride for 40% sorbitol plasticized films. It was concluded that up to 70% of whey powder could be utilized to produce biopolymer films by adding sorbitol and cross linkers at pH 10.

• Journal of the Korean Ceramic Society
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• v.13 no.3
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• pp.28-36
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• 1976

Zn 산화물을 산과 공기 그리고 헬륨 각각의 분위기에서 열처리 한 후 그 각각에 대한 열광성을 $83^{\circ}~300^{\circ}K$의 온도 범위에서 연구하였다. Zn 산화물의 열광성은 90$0^{\circ}C$ 이상의 온도에서는 산소의 부분압에 의존하며 그 최대강도는 1/T에 비례하였다. 이 성질을 유발한다고 믿어지고 있는 비화학양론적인 결함으 주 요인은 2개의 전자를 trap 하는 산호 이온의 vacancy라고 믿어지고 있다. Trap된 전자의 활성화에너지는 0.13ev였다.

• The Korean Journal of Zoology
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• v.36 no.2
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• pp.231-237
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• 1993

Lipophorin (LP) was purified from hemolvmph of late last instar larvae of Hyphuntria cuneo D. by KBr density gradient ultracentrifugation. Chemical composition of LP was investigated by electrophoresis, thin laver chromatography and ryas chromatography. LP consisted of Apo-LP I and Apo-LP ll, and M.W. of them were 230 Kd and 80 Nd, respectivelv. Lipid of LP was mostly composed of neutral lipid including triacylglvcerol, diacvlslvcerol, monoacylglvcerol and free cholesterol, and phospholipid rich in phosphatidvlethanolamine and phosphatidvlcholine. Fatty acids present in these lipids were found to have be 14:0, 16:0, 18:1, and 20:1.

• Journal of Korean Society of Forest Science
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• v.77 no.1
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• pp.43-52
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• 1988

One-year-old seedlings of Ginkgo biloba were treated with various simulated acid rains(pH 2.0, pH 3.0, pH 9.0 and pH 5.0) to examine the effects of simulated acid rain on the chemical properties of the tested soil. The seedlings were grown in a pot($4500cm^3$)containing one of three different soils(nursery soil, mixed soil and sandy soil). Simulated acid rain was made by diluting sulfuric and nitric acid solution($H^1SO^4$ : $HNO^3$ =3 : 1, V/V) with tap water and tap water(pH 6.4), and treated by 5mm each time for three minutes during the growing seasons(April to October 1985). Acid rain treatments were done three times per week to potted seedlings by spraying the solutions. The chemical properties of potting media were compared among three soil types as well as among the various pH levels. The results obtained in this study were as follows : 1. Exchangeable calcium and magnesium contents and base saturation of the soil decreased with decreasing pH levels of acid rain, and their decreasing rates were as follows : sandy soil was the highest, followed by mixed and nursery soils, However, exchangeable aluminum content rather increased as the pH levels decreased. 2. Available phosphate in the soil decreased as the pH levels of acid rain decreased. Its content increased in nursery soil, compared with those before acid gain treatment, Gut decreased in mined and sandy soils. 3. Soil sulfate and nitrate contents increased remarkably as the pH levels decreased, and the only significant difference in the sulfate was found among the pH levels. Soil sulfate content was the highest in nursery soil, followed by mixed and sandy soils.

• Microbiology and Biotechnology Letters
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• v.16 no.2
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• pp.92-97
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• 1988

Cysteinylglycinase was partially purified from Proteus mirabilis by consecutive procedure. The specific activity was increased about 16-fold to that of cell-free extract. The enzyme was found rather unstable on ammonium sulfate precipitation ann the precipitated enzyme protein became partially insoluble during dialysis. The precipitated enzyme was found to be solubilized by treatment of 4% Triton X-100 effectiviely, The optimum temperature and pH of the enzyme activity were 35$^{\circ}C$ and 7.3, respectively. After heat treatment of the enzyme at 5$0^{\circ}C$ for 30 min, it lost the activity to 70%. The enzyme was stable at pH 7.0-8.0. The molecular weight of the cysteinylglycinase was found to be about 190,000 by Sephadex G-150 gel filtration. The enzyme was activated by the addition of Mn$^{2+}$ and $Mg^{2+}$ ions. The maximal activation was obtained in preincubation with $Mg^{2+}$ ion for 30 min. The enzyme catalyzed the hydrolysis of various dipeptides and tripeptides. The Km and Vmax values for cysteinylglycine were 1.60 mM and 0.24 m unit/ mg, respectively.

• Journal of the Korean Chemical Society
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• v.38 no.11
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• pp.785-791
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• 1994

The $Sr_1-_xY_xMnO_3$ (x = 0.0∼1.0) system was synthesized using amorphous citrate process. The stability of various structures and the electronic transport properties of this system were investigated. X-ray diffraction study indicated that the $Sr_1-_xY_xMnO_3$ system has three different structures depending on composition, namely, 4L-hexagonal perovskite (when x is less than 0.3), pseudocubic perovskite (when x is 0.3∼0.7), and hexagonal nonperovskite (when x is larger than 0.7) structures. The structural changes and electronic properties were interpreted based on two factors, i.e., the size of cations and the oxidation state of manganese ion. When the concentration of Y substitution exceeds 30%, the Mn-Mn repulsive interaction dominates over intermetallic attraction, and thus structure changes to pseudocubic perovskite. In perovskite phase the unit cell dimensions increases with increasing $Mn^{3+}$ ions due to yttrium substitution. The band gap of $Sr_{0.9}Y_{0.1}MnO_3$ is greater than that of $Sr_{0.5}Y_{0.5}MnO_3$. The greater band gap of $Sr_{0.9}Y_{0.1}MnO_3$ indicates that the 4L-hexagonal structure is more stabilized than cubic perovskite due to the Mn-Mn bond.

• Journal of the Korean GEO-environmental Society
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• v.5 no.2
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• pp.23-31
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• 2004

Trichloroethylene(TCE), Cr(VI), and nitrate removal efficiency of a novel reactive barrier were experimented, and the types of corrosion species that form on the surface of the iron and bentonite as a result of reaction were investigated with Raman spectrophotometer. The reactive barrier is composed of bentonite and zero valent iron(ZVI), and this can substitute conventional geosynthetic clay liners for landfill leachate. Tests were performed in batch reactors for various ZVI content (0, 3, 6, 10, 13, 16, 20, 30, 100 w/w %) and pH. The reduction rates and removal efficiencies of TCE, Cr(VI) and nitrate increase at pH 7 buffered solution. As ZVI content increases, TCE, Cr(VI) and nitrate removal efficiencies increase. From the result of analysis with Raman spectrophotometer, Fe-oxides were observed, which are strong adsorbers of cantaminants. Magnetite can be also beneficial to the long term performance of the iron metal.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.21 no.2
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• pp.105-111
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• 1985

Optical properties of sea water were studied in the entrance of Tokyo Bay, Japan, based on the data obtained from six oceanographic stations in April, 1985. The observation of surface irradiance and underwater irradiance of sea water for eight kind of wavelengths (378, 422, 481, 513, 570, 621, 653, 677 nm) of sun light was conducted using the underwater irradiameter (Isigawa # SR-8). The mean attenuation coefficient of the sea water was appeared to be 0.300 (0.034-0.774) and the attenuation coefficient of the sea water for wavelength appeared such as 0.230 for 378 nm, 0.258 for 422 nm, 0.266 for 481 nm, 0.213 for 513 nm, 0.195 for 570 nm, 0.378 for 621 nm, 0.402 for 653 nm, 0.498 for 677 nm. The transparency was 7.2 m (6-9.5 m) and water color was 9 (6.5-10.5) in the study area and the sun's altitude 52.56$^{\circ}$(31.68-66.76$^{\circ}$). The relationship between attenuation coefficient (K) and transparency (D) was K=2.61/D (1.76/D-4.13/D). The rates of light penetration for eight kind of wavelengths (378, 422, 481, 513, 570, 621, 653, 677 nm) were computed with reference to the surface light intensity respectively. The mean rates of light penetration in proportion to depths were 69.30% (57.33-77.40%) in 1 m layer. 17.66% (6.3-27.90%) in 5 m layer, 4.47% (0.60-9.17%) in 10 m layer, and 0.77% (0.02-1.97%) in 20 m layer. The rates of light penetration at the transparency layer with reference to the surface light intensity was shown as 9.91% (0.51-22.99%).

• Current Research on Agriculture and Life Sciences
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• v.5
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• pp.75-80
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• 1987

We investigated physico-chemical properties of hard wheat flours for frozen yeast-raised breadmaking and freezing stability of frozen dough prepared by the straight no-time method. The general Composition of wheat flours were : moisture ; 14.0%, ash ; 0.48%. protein ; 13.15%, and dry gluten ; 13.43%. In farinograph data, development time and water absorption were 5.5 mimutes and 62 %, respectively. Amylograph maximum viscosity was 500 BU. Resistance to extention increased with the time and their extensibility decreased in the extensigraph data. From these results obtained from these physico-chemical properties, it was confirmed that the used wheat flours were most suitable for bread-baking. Considering effect of gassing power on cold storage period and fermentation time, it was effective that dough temperature should be adjusted to $20^{\circ}C$ in order to decrease freezing injury and maintain freezing stability.