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Mean Field Analysis of Exchange Coupling in Amorphous RE$Fe_2$-B (RE=Dy, Sm) Alloy Ribbons (비정질 RE$Fe_2$-B (RE=Dy, Sm) 합금 리본에서 평균장 이론에 의한 교환상호작용 계산)

  • Lee, J. M.;J. K. Jung;S.H. Lim
    • Journal of the Korean Magnetics Society
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    • v.11 no.3
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    • pp.85-96
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    • 2001
  • Experimental magnetization-temperature curves for melt-spun ribbons of amorphous alloys (Dy$\_$0.33/Fe$\_$0.67/)$\_$1-x/B$\_$x/(x=0 ,0.05, 0.1, and 0.15) and (Sm$\_$0.33/Fe$\_$0.67/)$\_$1-x/B$\_$x/(x=0, 0.01, 0.02, and 0.03) (in atomic fraction) are fitted with theoretical equations based on the mean field theory in order to calculate exchange couplings between constituent elements as a function of the B content. In the case of the DyFe$_2$-B system, the sign of the exchange coupling between Dy and Fe is negative, indicating that the magnetization direction of Dy is antiparallel to that of Fe. The sign of the other two couplings are positive indicating a parallel alignment. The exchange coupling between Fe ions are greatest, while that between Dy ions is negligible. In the case of the SmFe$_2$B alloys, the sign of all the couplings are positive, indicating ferromagnetic coupling between the spins. The exchange couplings between Fe ions, and Fe and Sm are comparable to each other, but they are much greater than that between Sm ions. The high exchange coupling between Fe and Sm, which is considered to occur indirectly, is rather unexpected, but it is considered to be unique characteristics of amorphous Sm-Fe alloys. In both alloy systems, the exchange coupling between Fe ions increases with increasing B content. and this may be explained by the increase of the Fe-Fe separation with increasing B content. The exchange coupling between Fe and RE also increases with increasing B content. As the B content increases, the magnetization decreases over the whole temperature range, and the Curie temperature also decreases.

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A Consideration on Intraspecific Competition with Particular Reference to Basal Area-class Structure of Even-aged Coniferous Monocultures (침엽수 동령 인공림내 개목들의 저적면적빈도분포에 의거한 종내경쟁에 대한 고찰)

  • 오계칠
    • Journal of Plant Biology
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    • v.24 no.1
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    • pp.47-57
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    • 1981
  • Girth at breast height was measured to test skewness ($g_1$) and kurtosis ($g_2$) of frequency distribution of the basal area in terms of t-test and Kolmogorov-Smirnov test for a total of forty six monocultures within Sudong and Kwhangnung area in central part of Korean peninsula in 1979 and 1980. The monocultures are about 10 to 50 years old, and four kinds: Pinus koraiensis, Larix kaempferi, Abies holophylla and Pinus rigida. Most of the sample sizes per site were ranged 70 to 110 excluding 4 sites. The number of classes interval was based on Sturges rule for each monoculture and was ranged from 5 to 10. In Sudong the range of age(yr) and basal area (($cm^2$)/tree) of the monocultures were from 10 to 20 and from 27.60 to 383. for Kwhangnung they were from 15 to 47 and mostly 102.15 to 619.14, respectively. All 43 monocultures except 1 showed +$g_1$, which ranged from 0.3 to 2.2 except six sites. Of the total 46 sites, 23 sites showed significant +$g_1$ which includes about 10 year-old monoculture. The number of classes interval with significant positive skewness ranged from 6 to 9. The data suggest that intraspecific competition in terms of stand structure seems to appear from about 10 year-old monocultures, and it may even last to about 50 year-old one. Around 24 monocultures showed nonsignificant -$g_2$ except one. Most -$g_2$ ranged from -0.12 to -0.83. Around 20 monocltures showed positive $g_2$ ranging from +0.13 to +3.841. Of the 22 +$g_1$, majority of 11 were very highly significant. Of all monocultures only 5 showed significant result from Kolmogorov-Smirnov test. Of the 4 species, Larix kaempferi seems to show density stress first then Abies holophylla, and Pinus koraiensis last. Data of this study indicate that adequate number of classes intervals and sample sizes for studying intraspecific competition in terms of basal area are 6 to 9 and 80 trees rather than 12 and 100 trees, respectively. It also suggests that most of the frequency distribution of basal area class are trimodal rather than bimodal under density stress. It is proposed that the leptokurtic distribution appears before normal distribution rather than direct change from platykurtic to normal distribution of basal area for selected stages in the development of stands.

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Growth characteristics of pathogens isolated from surface of carcass (도체표면에서 분리한 병원성 미생물의 성장특성)

  • 정영숙;박나영;이신호
    • Food Science and Preservation
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    • v.9 no.4
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    • pp.434-440
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    • 2002
  • The growth characteristics of 5. coli O157:H7 CDFI, A. sobria CDF3 and S. aureus CDF2 isolated from surface of carcass were investigated to improve hygienic quality of beef. The total count of carcass surface before washing was higher than that of after washing. Total count of after cooling decreased about 10$^1$∼ 10$^2$/㎠ compare with before cooling. Total count of carcass surface after transfer increased regardless seasons. The growth E. coli O157:H7 CDF1 occurred at pH 4 and 6% NaCl but A. sobria CDF3 and S. aureus CDF2 did not grow at the same conditions. Although the growth of E. coli O157:H7 CDF1 and S. aureus CDF2 was inhibited by 0.3% lactic acid, but A sobria CDF3 did not grow in TSB containing 0.3% lactic acid. E. coli O157:H7 CDF1 grew rapidly after 3 days incubation at 10$\^{C}$ but did not grow at 4$\^{C}$. But A. sobria CDF3 grew rapidly after 3 days incubation at 4$\^{C}$. E. coli O157:H7 CDF1 and A. sobria CDF3 were destroyed by heat treatment for 3 min at 60$\^{C}$. S. aureus CDF2 did not detect after heat treatment for 2 min at 70$\^{C}$.

Effect of Lotus Root(Nelumbo nucifera G.) on Lipid Metabolism in Rats with Diet - Induced Hypercholesterolemia (연근이 고콜레스테롤혈증 흰쥐의 지질대사에 미치는 영향)

  • Lee, Jae-Joon;Park, Se-Young;Lee, Myung-Yul
    • Food Science and Preservation
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    • v.13 no.5
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    • pp.634-642
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    • 2006
  • This study was performed to investigate the effects of lotus root ethanol extinct (LRE) on 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity in vitro, and lipid metabolism in the serum and liver of rate fed normal or high cholesterol diet in vivo. LRE (200 mg/kg/day and 400 mg/kg/day) was administered only to rats with fed high cholesterol diet for 6 week. We divided into 6 groups: normal diet group (NC), high cholesterol diet group (1% cholesterol and 0.25% sodium cholate)(HC), LRE 200 mg/kg treated group (NC-LREL), LRE 400 mg/kg teated group (NC-LREH), high cholesterol diet and LRE 200 mg/kg treated group (HC-LREL), and high cholesterol diet and LRE 400 mg/kg teated group (HC-LREH). LRE significantly inhibited the HMG-CoA reductase activity in a concentration-dependent manner in vitro. The body weight gain and liver weight of the high cholesterol diet group were higher than the normal diet group whereas the groups administered LRE were gradually decreased. The high cholesterol diet group increased serum triglyceride, total cholesterol, free cholesterol and LDL-cholesterol levels, and decreased atherogenic index, HDL-cholesterol and phospholipid levels as compared with the normal diet group. LRE administrated groups were increased in serum HDL-C/T-C, HDL-cholesterol and phospholipid levels, and decreased serum triglyceride, total cholesterol, free cholesterol, and LDL-cholesterol levels as compared with the high cholesterol diet group. These effect of LRE within the high cholesterol diet groups were concentration-dependent manners. There were no differences in the levels of serum triglyceride, total cholesterol, phopholipid, HDL-cholesterol and free cholesterol between normal diet groups. The hepatic LRE administrated groups than in the high cholesterol diet group. Teken together, it is suggested that LRE exerts hypocholesterolemic effect by reducing serum cholesterol concentration in rats with high cholesterol diet-induced hypercholesterolemia.

Rapid Fermentation of Freeze-Concentrated Ice Apple Wine by a Sugar Tolerant Yeast, Saccharomyces cerevisiae SS89 (내당성 효모 Saccharomyces cerevisiae SS89에 의한 동결농축 사과즙의 무가당 아이스 사과주 속성 발효)

  • Choi, Sang-Hoon;Baek, Seong-Yeol;Yeo, Soo-Hwan;Park, Heui-Dong
    • Food Science and Preservation
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    • v.19 no.3
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    • pp.413-419
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    • 2012
  • Fermentation of ice apple wine from freeze-concentrated Fuji apple juice to 36 $^{\circ}Brix$ was carried out using Saccharomyces cerevisiae SS89, a sugar-tolerant wine yeast strain. The characteristics of the fermentation and the properties of ice apple wine were compared with those of S. cerevisiae W-3, an industrial wine yeast that was used as a control in this study. During the fermentation, the alcohol content increased more rapidly by S. cerevisiae SS89 together with the decrease of the soluble solid content, compared to S. cerevisiae W-3. It reached 12% (v/v) after 15 days of fermentation by S. cerevisiae SS89 (12.4%, v/v) and 21 days by S. cerevisiae W-3 (12.6%, v/v). The soluble solid contents of the SS89 and W-3 wines were 24.0 and 23.6 $^{\circ}Brix$, respectively. Lactic acid was detected at the highest level, followed by malic aid, among the organic acids in both wines. No big differences in the organic acid contents were observed based on the strains. In the SS89 wine, higher levels of methanol, propanol, butanol, and isoamyl alcohol were detected, together with a lower isobutanol content, compared with the W-3 wine. The SS89 wine showed higher level of intensity as well as higher Hunter's L and b color values compared to the W-3 wine. In the sensory evaluation, similar scores in color, flavor, taste, and overall preference were obtained in the two wines. Therefore, S. cerevisiae SS89 was thought to be useful for the rapid fermentation of ice apple wine.

Fermentation Characteristics of Freeze-Concentrated Apple Juice by Saccharomyces cerevisiae Isolated from Korean Domestic Grapes (국산 포도로부터 분리된 Saccharomyces cerevisiae에 의한 동결농축 사과주스의 알코올 발효특성)

  • Choi, Sang-Hoon;Choi, Yoon-Jung;Lee, A-Rong;Park, Seon-A;Kim, Dong-Hyun;Baek, Seong-Yeol;Yeo, Soo-Hwan;Rhee, Chang-Ho;Park, Heui-Dong
    • Food Science and Preservation
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    • v.18 no.4
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    • pp.559-566
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    • 2011
  • In this study, the good brewing conditions for the 24 $^{\circ}Brix$ freeze-concentrated apple wine were investigated. The four selected Saccharomyces cerevisiae strains MM10, SS89, SS812, and WW108, could ferment quickly when brewed with high sugar levels. During the fermentation, the reducing sugar contents slowly declined while the total acid in all the yeasts increased and the final alcohol content was 12-13%, a typical wine's alcohol content. The viable counts were shown to be 6-6.8 log cfu/ml. During the fermentation, the organic acid content was shown to be within the range of 2.36-3.11%, and the free sugar content, except for the SS89 and WW108 strains, was shown to consist only of sorbitol, although fructose was somewhat detected in the SS89 and WW108 strains. Methanol was not detected, or only a trace of it was detected, and the aldehyde content was 107.68-114.27 ppm. As for the fusel oil contents, a trace of propanol was detected. Isobutanol and butanol were present in 40.16-54.65 and 25.47-27.73 ppm, respectively. The isoamy1 alcohol content was shown to be the highest (108.88-217.26 ppm). The final total phenolic compounds were shown to be 0.1-0.16%. The final Hue values were shown to be 1.3-3.6, and the final intensity was 0.1-0.45. The lightness (L) was within the range of 91.78-98.51, the redness (a) was at a neutral position at red and green, and the yellowness (b) was within the range of 2.38-7.7. In the sensory evaluation, the SS812 strain was found to be the best in terms of color, the SS89 strain in terms of odor, and the WW108 strain in terms of taste. Overall, SS812 was found to be the best apple wine.

Analysis of Nutrient Composition of Baechu Kimchi (Chinese Cabbage Kimchi) with Seafoods (수산물을 첨가한 배추김치의 영양성분 분석)

  • Jang, Mi-Soon;Park, Hee-Yeon;Park, Jin-Il;Byun, Han-Seok;Kim, Yeon-Kye;Yoon, Ho-Dong
    • Food Science and Preservation
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    • v.18 no.4
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    • pp.535-545
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    • 2011
  • The nutrient composition, including the proximate composition and the mineral, vitamin, amino acid, and free-amino-acid levels, of baechu kimchi (Chinese cabbage kimchi) to which 14 kinds of seafood (flatfish, yellow corvina, sea beam, pollack gizzard shad, ray, gray mullet, skate, hairtail, anchovy, sea squit, pen shell, scallop, small octopus)were added was analyzed. The seafoods were added to salted cabbage at concentration of 10% (w/w) and the prepared seafood baechu Kimchi (BK) was stored at $5^{\circ}C$ for seven days. The levels of moisture (82.09-88.56%), crude lipid (0.31-0.64%), and crude ash (2.70-3.50%) did not differ much among the samples, but the level of crude protein of the BK-with-seafood samples (2.42-5.15%) was greater than that of the control BK (2%), without seafood. The Fe and Ca contents of BK with flatfish showed the highest values (4.1 and 74 mg/100 g, respectively). The vitamin A contents of BK samples with 14 different kinds of seafood were higher than that of the control BK. Moreover, the BK with sea squit had higher vitamin $B_2$ (0.90 mg/100 g) and vitamin C (8.48 mg/100 g) contents among all the BK-with-different-kinds-of-seafood samples. Total amino acids were detected in all BK-with-seafood samples, most of which had high levels of glutamic acid, aspartic acid, proline and alanine. Glutamic acid was the most abundant of all the amino acids. The major free amino acids were hydroxyproline, glutamic acid, alanine, proline, leucine, and valine, of which hydroxyproline was the most abundant. In conclusion, BK with seafood is thought to be a very good source of protein, which is very important from dietary life of humans.

Antioxidative Activities and Tyrosinase Inhibition Ability in Various Extracts of the Vitex rotundifolia Seeds (만형자(Vitex rotundifolia) 추출물의 항산화 활성과 Tyrosinase 저해 활성)

  • Lee, Yang-Suk;Choi, Bok-Dong;Joo, Eun-Young;Shin, Seung-Ryeul;Kim, Nam-Woo
    • Food Science and Preservation
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    • v.16 no.1
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    • pp.101-108
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    • 2009
  • The purpose of this study was to measure flavonoid and polyphenol contents, and physiological activities of various extracts from Vitex rotundifolia seeds (known as Man Hyung Ja). We obtained three extracts using water (WE), ethanol (EE) and hot water (HWE). The EE sample had the highest flavonoid content of 31.05 mg/g. Polyphenol contents of WE and HWE were 186.69 mg/g and 182.55 mg/g, respectively. HWE had the highest superoxide dismutase (SOD)-like activity, at 83.40%. The electron donating abilities (EDA) were $91.14{\sim}95.97%$ at the concentration of 1.0 mg/mL, and all of extracts showed more than 88% EDA even at a concentration of 0.1 mg/mL. The inhibitory rates of xanthine oxidase were $94.02{\sim}97.51%$ when 1.0 mg/mL extracts were used, and all extracts showed more than 90% inhibition at 0.5 mg/mL. The nitrite scavenging abilities were $59.27{\sim}86.61%$ at pH 1.2 and 1.0 mg/mL extract concentration; these abilities decreased as pH increased. Tyrosinase inhibition activities of HWE and WE were 48.58% and 46.67%, respectively. These results indicate that Vitex rotundifolia seeds extract might be an effective antioxidative activity.

Study on the Quality of Apple Dressing Sauce Added with Pine Mushroom(Tricholoma matsutake Sing) and Chitosan (송이버섯과 키토산을 첨가한 사과 드레싱 소스의 품질에 관한 연구)

  • Hong, Ju-Yeon;Choi, Young-Jun;Kim, Mi-Hyun;Shin, Seung-Ryeul
    • Food Science and Preservation
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    • v.16 no.1
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    • pp.60-67
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    • 2009
  • The purpose of this research was to develop the apple dressing sauce added pine mushroom (Tricholoma matsutake Sing.) and chitosan which has excellent functionality and scent. An apple dressing sauce with pine added to it was manufactured and tested for sensuality and also for quality changes during storage. The sensory test of the sauces added pine mushroom, the apple dressing sauce added pine mushroom and the apple dressing added pine mushroom and chitosan scored high points. The chromaticity of the apple dressing sauce with pine mushroom compared to the pine didn't show much difference in the L, a, b values and also in the sauces added pine and chitosan, the apple dressing showed less change. At $4^{\circ}C$ and 25, the viscosity of the sauces with pine mushroom showed a small increase in all samples as the storage duration went on. At $4^{\circ}C$, a continuous decrease of the pH was seen in all of the apple dressing sauce added with pine mushroom on storages and from 30 days the pH seemed to start increasing slightly. During storage, the titratable acidity in all samples of the apple dressing with pine mushroom at $4^{\circ}C$ and $25^{\cird}C$ seemed to some what increase as the term went on but there was no significant differences to the acidity. At $4^{\circ}C$, the total viable cells in the apple dressing with pine mushroom showed $1.7{\times}10^{2}CFU/g$ which was the lowest in the beginning of storage period but as the storage period grew longer the total viable cells increased in all of the samples.

Antioxidant activities of commonly used Brassica spp. sprout vegetables in Korea (국내 다소비 십자화과 새싹채소 추출물의 항산화 활성)

  • Shin, Gi-Hae;Lee, Young-Jun;Kim, Jae-Hwan;Kim, Young-Hyoun;Kim, Dan-Bi;Lee, Jong Seok;Lim, Jeong-Ho;Lee, Ok-Hwan
    • Food Science and Preservation
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    • v.21 no.4
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    • pp.587-592
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    • 2014
  • Brassica spp. vegetables have been known to have biological activities such as anti-cancer and anti-inflammatory activities. In this study, we investigated the in vitro physicochemical characteristics and antioxidant activities of commonly used Brassica spp. sprout vegetables such as kohlabi (Brassica oleracea var. gongyloides), red radish (Raphanussativus L. var. sativus), broccoli (B. oleracea var. italica), cabbage (B. rapavar. glabra Regel), rape (B. napus), radish (R. sativus), and tatsoi (B. campestris var. narinosa) sprouts. Our results showed that the vegetables with the highest total phenolics contents were the radish sprout ($24.40{\pm}1.24mg\;TAE/g$) and kohlabi sprout extracts ($23.97{\pm}0.46mg\;TAE/g$). Furthermore, the vegetable with the highest total flavonoid content was the radish sprout extract ($15.30{\pm}1.35mg\;CE/g$). However, the kohlabi sprout extract showed the highest DPPH radical scavenging value ($IC_{50}=1.95mg/mL$) and ORAC value (79.03 mM TE/g). In addition,the six kinds of Brassica spp. sprout vegetable extracts, except tatsoi, significantly inhibited the reactive oxygen species (ROS) production and showed that intracellular oxidative stress is closely related tothe accumulation of differentiated adipocytes and fat during the adipogenesis of 3T3-L1 preadipocytes. These results suggest that Brassica spp. sprout vegetables, especially kohlabi and radish sprout extracts, can be used to develop natural antioxidants.