• Korean Journal of Soil Science and Fertilizer
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• v.12 no.1
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• pp.1-14
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• 1979

The fertility which is the combined factor is one of the important capability determiants of paddy soils. In this study, we aimed at attaining a quantitative evaluation of soil fertility and further establishing an objective fertility classification on the basis of the fertility evaluation. The samples used in this series studies were collected from Korean paddy field. They include deltas, flood plains, coastal plains, valley plains, fans and low terraces. On the basis of correlation analysis, factor analysis was applied to a set of 15 variables. As a result of factor analysis, five mutually independent and clearly definable fertility component factors were extracted from the 15 variables for the whole 90 surface soil samples. The fertility status of each sample soil could be objectively designated by the score of the five factors. As a means of summarizing the information obtained, taxonomic distances between all pairs of the samples were computed from these five factor scores further to be subjected to numerical taxonomy. Seven fertility groups were formulated, each of which was characterized by one or more of the fertility components. As this fertility classification was based on the present state of soil properties, it would be useful in pointing to the proper direction of further fertility amelioration and improvement for each group to enhance potential productivity of Korean paddy fields.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.2
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• pp.79-85
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• 1991

This study reports on the physical and chemical properties of the whole soils (<2mm) derived from five major rocks of granite, granite-gneiss, limestone, shale, and basalt in Korea. The properties were considered from the kind and frequency distribution of rock-forming minerals in the parent rocks. In particle size distribution, sand fractions were high in the soils from granite-gneiss, silt fractions mainly, in the residual soils from limestone, shale, and basalt. And clay fractions were particularly high in the colluvial soil from limestone and the old alluvial soil from basalt. pH, extractable Ca and Mg, and cation exchange capacity of the soils derived from limestone might be considered to be high due to the presence of sand and/or silt-sized calcite and dolomite inherited from the parent rocks. However, the soils derived from granite and granite-gneiss, being abundant in feldspars, quartz, and micas, showed a tendency to the contrary. A soil from shale composing of high quartz tended to have pH. extractable Ca, base saturation, and low exchangeable Al. In total element analysis, the soils derived from parent rocks with high contents of (i) orthoclase and micas, (ii) biotite, primary chlorite, and augite, and (iii) carbonate minerals and plagioclase as a rock-forming mineral showed a tendency to decrease the contents of $K_2O$, $Fe_2O_3$ and MgO, and CaO in comparison with those of their parent rocks.

• Journal of Sericultural and Entomological Science
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• v.47 no.2
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• pp.51-55
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• 2005

Resveratrol is naturally occurring phytoalexin compounds produced by grape berries, peanuts, and their products in response to stress such as fungal infection, heavy metal ions or UV irradiation. The objective of this study was to develope a reliable high performance liquid chromatographic (HPLC) method for the quantitative determination of trans-resveratrol in mulberry fruit. Samples were extracted in 80% MeOH and filtered with $0.45{\mu}m$ syringe filter. The transresveratrol was separated Waters $C_{18}$ column, using a mobile phase containing 0.025% trifluroacetic acid in 5% acetonitril and 0.035% trifluroacetic acid in 50% acetonitril, detected by photodiode array detector (PDA) at 254 nm and the flow rate was 1ml/min. Under this analytical condition, the mean content of mulberry fruits (fifty varieties) was $777.3{\pm}585.9ppm$. Among the tested samples, 'Mansaengbaekpinosang (II)' was the highest level in 3450.6 ppm. However four accessions including 'Gukbu', 'Sabangso (I)', 'Simseol' and yield mulberry fruit were not able to detected. Eight suitable varieties selected for the production of fruit were 'Jeolgokchosaeng (Chungbuk)' 777.8 ppm, 'Dangsang 7' 771.1 ppm, 'Jangsosang' 133.9 ppm, 'Susungppong' 31.1 ppm, 'Suwonnosang' 639.7 ppm, 'Palcheongsipyung' 1475.9 ppm, 'Kangsun' 864.0 ppm, and 'Jukcheonchosaeng' 1458.5 ppm. 'Daesungppong' which was the first authorized variety for the production of mulberry fruit was 1236.7 ppm. In conclusion, these results suggest that mulberry including fruit and leaf may a good new resource for resveratrol production.

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.1-8
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• 1997

A complement system-activating (anti-complementary) polysaccharide was purified from the hot water extract of young stems of Cinnamomum cassia Blume. Crude polysaccharide fraction (CC-1) was prepared from the hot water extract of the young stems followed by methanol-reflux, precipitation with ethanol, dialysis, and lyophilization. The anti-complementary activity of CC-1 was decreased greatly by periodate oxidation, but was not changed by pronase digestion. These suggest that carbohydrate moiety may be related to the activation of complement system. According to its ionic strength CC-1 was fractionated first using cetavlon to give 4 fractions, CC-2, 3, 4 and 5. Among them CC-2 fraction was found to retain the highest activity and yield. CC-2 was separated to an unabsorbed neutral sugar portion (CC-2-I) and seven absorbed acidic sugar fractions $(CC-2-II{\rightarrow}CC-2-VIII)$ on DEAE-Toyopearl 650C (Cl-). CC-2-III showing higher anti-complementary activity and yield than those of other fractions, was further purified on the gel permeation of Sephadex G-100 and Sepharose CL-6B to CC-2-IIIa-3. CC-2-IIIa-3 was determined to have a homogeneity hy GPC (Sepharose CL-6B) and HPLC. Gel chromatography using standard dextrans gave a value of $2.4{\times}10^5$ for the molecular weight. The purified polysaccharide, CC-2-IIIa-3 consisted of arabinose, xylose, glucose, galactose, galacturonic acid and glucuronic acid in a molar ratio of 5.56 : 3.77 : 1.87 : 1.00 : 5.12 : 3.13 and contained no nitrogen.

• Korean Journal of Medicinal Crop Science
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• v.1 no.1
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• pp.16-23
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• 1993

Seeds of Acanthopanx plants need about 2 years to germinate after sowing even if full matured fruits were harvested. I leave a room for doubt that this phenomenon could be brought by the immatured embryo in seed. If it is true, stratification method for the seed propagation of Acanthopanax plants would be used more effectively to promote the growth of embryo in relatively short time. Before stratification, seeds were devided into two parts. One of them was treated for 24hrs in the concentration of $GA_3$ 100 ppm. After stratification of non-treated and treated seeds, seeds for microtechnique were taken on interval of one month for three months, and fixed in Farmer's solution. The seed sizes of Acanthopanax plants were in biggest order A. sessiliflorus, A. seoulense, A. chiisanensis, A. koreanum and A. sieboldianum. The dehiscence phenomenon of seed coat didn't show in most of the seeds that stratified, but A. koreanum only dehisced in seeds treated in $GA_3$ 100ppm. The embryos of the stratified seeds that treated in $GA_3$ showed nomal growth, complete cotyledons and procambium in hypocotyl in any species, but the non-treated seeds could not expect the germination after sowing due to poor growing of the embryo in all species. In view of the results so far achieved, it has taken long times from sowing to germinate because the seed of Acanthopanax plants has immatured embryo.

• Korean Journal of Microbiology
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• v.39 no.2
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• pp.95-101
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• 2003

The total bacterial numbers, Eubacterial community structures and environmental factors which affect bacterial community were estimated monthly using DAPI and fluorescent in situ hybridization monthly, from June to November 2000 to evaluate the correlation between the bacterial community and environmental factors in eutrophic agricultural Masan reservoir in Asan. Average water temperatures varied from 12.3 to $27.5^{\circ}C$, pH 7.5 to 9.0, DO 7. I~12.8 mg/L, COD 6.4~13.0 mg/L, chlorophyll a 30.5~99.0 mg/㎥, SS 7.S~25.7 mg/L, TN 1.748~3.543 mg/L., and TP 0.104~0.581 mg/L, respectively. Total bacterial numbers showed high ranges from 0.4 to 9.6$\times$ $10^{6}$ cells/ml, and these indicated the mesotrophic or eutrophic state. The ratio of Eubacteria to total bacteria was 67.6-88.0%, which was higher than that in other reservoir. The relationships of total bacteria and Eubacteria community were more significant with organic nitrogen (Org-N), and organic phosphorus (Org-P) than with water temperature. Proteobacteria groups showed strongly significant relationships with Org-P and Org-N and significant relationships with water temperature, conductivity, COD, and inorganic nitrogen. C-F group was the most significant with Org-N, and HGC group with water temperature. However, relationships of Chl-a, pH, DO and SS showed no significance with any bacterial community. These results were different from other studies, because of the specific characteristics of Masan reservoir such as old, shallow and eutrophic states. The seasonal variation of bacterial community in Masan reservoir does not seem to depend on phytoplankton dynamics but on storm event and organic materials from watershed and the sediment of reservoir.

• Korean Journal of Poultry Science
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• v.33 no.1
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• pp.33-39
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• 2006

This study was conducted to investigate the feeding effect of $bio-silverlite^{(R)}$ on growth performance, organ phenomenon and cecum microflora in broiler chicks. The $bio-silverlite^{(R)}$ was made by an ion exchange between illite and $silver(Ag^+)$. There were four treatment groups: negative control group(non-treatment), antibiotic supplement group (positive control), 0.5% $bio-silverlite^{(R)}$ supplment group and 1.5% $bio-silverlite^{(R)}$ supplement group. Total 200 birds was assigned for this five replication tests, allocating 10 birds into each treatment. Experimental diets were formulated on isocalories and isonitrogen for the whole experimental period. Body weight gain was higher in antibiotic supplementation (+C) and $bio-silverlite^{(R)}$ supplement groups(S 0.5% and 51.5%) than the negative control group(-C), and feed efficiency was significantly enhanced with increase of the level of $bio-silverlite^{(R)}$ supplement. The length of small intestine was longer in +C than in -C and $bio-silverlite^{(R)}$ supplement groups (P<0.05), and the weight of small intestine was proportional to the level of $bio-silverlite^{(R)}$ supplement. Crop weight was lower in $bio-silverlite^{(R)}$ supplement group than in -C and +C groups (P<0.05), and the cecum weight was heavier in $bio-silverlite^{(R)}$ supplementation group. Intestinal villi height was longer in 51.5% group at 3 weeks and 6 weeks of age than in -C and +C groups. With the respect of the formation of intestinal microflora, TBC and CBC was not affected by age and feed additive. However, the number of LAB was slightly higher in $bio-silverlite^{(R)}$ supplement group than in -C and +C groups.

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.45-47
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• 2002

반도체 소자의 고집적화 및 고속화가 요구됨에 따라 MOSFET 구조의 게이트 절연막으로 사용되고 있는 SiO₂ 박막의 두께를 감소시키려는 노력이 이루어지고 있다. 0.1㎛ 이하의 소자를 위해서는 15Å 이하의 두께를 갖는 SiO₂가 요구된다. 하지만 두께감소는 절연체의 두께와 지수적인 관계가 있는 누설전류를 증가시킨다[1-3]. 따라서 같은 게이트 개패시턴스를 유지하면서 누설전류를 감소시키기 위해서는 높은 유전상수를 갖는 두꺼운 박막이 요구되는 것이다. 그러므로 약 25정도의 높은 유전상수를 갖고 5.2～7.8 eV 정도의 비교적 높은 bandgap을 갖으며, 실리콘과 열역학적으로 안정한 물질로 알려진 HfO2[4-5]가 최근 큰 관심을 끌고 있다. 본 연구에서는 HfO₂ 박막을 실제 소자에 적용하기 위하여 전극 및 열처리에 따른 HfO₂ 박막의 미세구조 및 전기적 특성에 관한 연구를 수행하였다. 이를 위해, HfO₂ 박막을 reactive DC magnetron sputtering 방법으로 증착하고, XRD, TEM, XPS를 사용하여 ZrO₂ 박막의 미세구조를 관찰하였으며, MOS 캐패시터 구조의 C-V 및 I-V 특성을 측정하여 HfO₂ 박막의 전기적 특성을 관찰하였다. HfO₂ 타겟을 스퍼터링하면 Ar 스퍼터링에 의해 에너지를 가진 산소가 기판에 스퍼터링되어 Si 기판과 반응하기 때문에 HfO₂ 박막 형성과 더불어 Si 기판이 산화된다[6]. 그래서 HfO₂같은 금속 산화물 타겟 대신에 순수 금속인 Hf 타겟을 사용하고 반응성 기체로 O₂를 유입시켜 타겟이나 시편위에서 high-k 산화물을 만들면 SiO/sub X/ 계면층을 제어할 수 있다. 이때 저유전율을 갖는 계면층은 증착과 열처리 과정에서 형성되고 특히 500℃ 이상에서 high-k/Si를 열처리하면 계면 SiO₂층은 증가하는 데, 이것은 산소가 HfO₂의 high-k 박막층을 뚫고 확산하여 Si 기판을 급속히 산화시키기 때문이다. 본 방법은 증착에 앞서 Si 표면을 희석된 HF를 이용해 자연 산화막과 오염원을 제거한 후 Hf 금속층과 HfO₂ 박막을 직류 스퍼터링으로 증착하였다. 우선 Hf 긍속층이 Ar 가스 만의 분위기에서 증착되고 난 후 공기중에 노출되지 않고 연속으로 Ar/O₂ 가스 혼합 분위기에서 반응 스퍼터링 방법으로 HfO₂를 형성하였다. 일반적으로 Si 기판의 표면 위에 자연적으로 생기는 비정질 자연 산화막의 두께는 10～15Å이다. 그러나 Hf을 증착한 후 단면 TEM으로 HfO₂/Si 계면을 관찰하면 자연 산화막이 Hf 환원으로 제거되기 때문에 비정질 SiO₂ 층은 관찰되지 않았다. 본 실험에서는 HfO2의 두께를 고정하고 Hf층의 두께를 변수로 한 게이트 stack의 물리적 특성을 살펴보았다. 선증착되는 Hf 금속층을 0, 10, 25Å의 두께 (TEM 기준으로 한 실제 물리적 두께) 로 증착시키고 미세구조를 관찰하였다. Fig. 1(a)에서 볼 수 있듯이 Hf 금속층의 두께가 0Å일때 13Å의 HfO₂를 반응성 스퍼터링 방법으로 증착하면 HfO₂와 Si 기판 사이에는 25Å의 계면층이 생기며, 이것은 Ar/O₂의 혼합 분위기에서의 스퍼터링으로 인한 Si-rich 산화막 또는 SiO₂ 박막일 것이다. Hf 금속층의 두께를 증가시키면 계면층의 성장은 억제되는데 25Å의 Hf 금속을 증착시키면 HfO₂ 계면층은 10Å미만으로 관찰된다. 그러므로 Hf 금속층이 충분히 얇으면 플라즈마내 산소 라디칼, 이온, 그리고 분자가 HfO₂ 층을 뚫고 Si 기판으로 확산되어 SiO₂의 계면층을 성장시키고 Hf 금속층이 두꺼우면 SiO/sub X/ 계면층을 환원시키면서 Si 기판으로의 산소의 확산은 막기 때문에 계면층의 성장은 억제된다. 따라서 HfO₂/Hf(Variable)/Si 계에서 HfO₂ 박막이 Si 기판위에 직접 증착되면, 순수 HfO₂ 박막의 두께보다 높은 CET값을 보이고 Hf 금속층의 두께를 증가시키면 CET는 급격하게 감소한다. 그러므로 HfO₂/Hf 박막의 유효 유전율은 단순 반응성 스퍼터링에 의해 형성된 HfO₂ 박막의 유전율보다 크다. Fig. 2에서 볼 수 있듯이 Hf 금속층이 너무 얇으면 계면층의 두께가 두꺼워 지고 Hf 금속층이 두꺼우면 HfO₂층의 물리적 두께가 두꺼워지므로 CET나 EOT 곡선은 U자 형태를 그린다. Fig. 3에서 Hf 10초 (THf=25Å) 에서 정전 용량이 최대가 되고 CET가 20Å 이상일 때는 high-k 두께를 제어해야 하지만 20Å 미만의 두께를 유지하려면 계면층의 두께를 제어해야 한다.

• Journal of Life Science
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• v.19 no.7
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• pp.994-1002
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• 2009

A bacteriocin-producing bacterium identified as Bacillus licheniformis was isolated from soybean sauce. Antibacterial activity was confirmed by paper disc diffusion method, using Micrococcus luteus as a test organism. The bacteriocin also showed antibacterial activities against Bacillus sphaericus, Lactobacillus bulgaricus, Lactobacillus planiarum, Paenibacillus polymyxa, and Pediococcus dextrinicus. Optimal culture conditions for the production of bacteriocin was attained by growing the cells in an MRS medium at a pH of 6.5~ 7.0 and a temperature of 37$^\circ$C for 36$\sim$48 hr. Solvents such as chloroform, ethanol, acetone, and acetonitrile had little effect on bacteriocin activity. However, about 50% of bacteriocin activity diminished with treatment of methanol and isopropanol at the final concentration of 50% at 25$^\circ$C for 1 hr. It was stable against a pH variation range from 3.0 and 7.0, but the activity reduced to 50% at a pH range from 9.0 to 11.0. It's activity was not affected by heat treatment at 100$^\circ$C for 30 min and 50% of activity was retained after heat treatment at 100$^\circ$C for 60 min, showing high thermostability. The bacteriocin was purified to a homogeneity through ammonium sulfate precipitation, SP-Sepharose ion-exchange chromatography, and reverse-phase high-performance liquid chromatography (HPLC). The entire purification protocol led to a 75-fold increase in specific activity and a 13.5% yield of bacteriocin activity. The molecular weight of purified bacteriocin was estimated to be about 2.5 kDa by tricine-SDS-PAGE.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.2
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• pp.71-78
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• 2000

Preferential flow has recently been the subject of increasing interest because these phenomena contribute to solute transport in soils. Commonly, preferential flow paths are associated with macropores or highly structured soils. We presented an analysis of the measured breakthrough curves (BTCs) of $Cl^-$ and $Cu^{2+}$ ions to test the occurrence of preferential flow in soils using miscible displacement technique under steady flow conditions. We also analyzed soil water retention curves and from this curves induced cumulative pore size distribution of undisturbed soils, which sampled from Ap1, B1, and C horizons of Songjeong series soils (the fine loamy, mesic family of Typic Hapludults). In this study, miscible displacement experiment on C horizon was excluded, because it is structureless sandy loam with saturated hydraulic conductivity of $5.2cmhr^{-1}$. The saturated hydraulic conductivity of Ap1 horizon was $2.0cmhr^{-1}$, which was about 7 times higher than that of B1 horizon ($0.27cm hr^{-1}$). Cumulative pore size distribution predicted that Ap1 horizon had more macropores (pore diameter larger than $49{\mu}m$, equivalent to -6 kpa of soil matric potential) than B1 horizon. The hydrodynamic dispersion coefficient from chloride BTCs was estimated as $1.3cm^2hr^{-1}$ for B1 and $34cm^2hr^{-1}$ for Ap1 horizon. However the retardation factors of B1 and Ap1 horizon were significantly different, i.e. 1 and 0.6, respectively, which means that there was distinct partition between mobile water and immobile phase in Ap1 horizon. The copper retardation effect of Ap1 horizon was less than that of B1 horizon, even though cation exchange capacity of Ap1 horizon was higher than that of B1 horizon. Thus, breakthrough curves of $Cl^-$ and $Cu^{2+}$ obviously showed the probability that preferential flow would occur in Ap1 horizon.