• KSBB Journal
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• 제26권6호
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• pp.552-556
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• 2011

A novel agar-degrading bacterium mbrc-1 was isolated from seashore of Kyungpo at Gangwon province and cultured in marine broth 2216 medium. Isolated bacterium mbrc-1 was named as Flammeovirga sp. mbrc-1 based on the 16S rDNA sequence. Its agarase showed maximum activity of 923 units/L at pH 7.0 and $45^{\circ}C$ and sustained 90% remaining activity after exposed to $45^{\circ}C$ for 2 hours. The enzyme hydrolyzed agarose to yield neoagarohexaose (18.5%), neoagarotetraose (38%) and neoagarobiose (43.5%), indicating that the enzyme is ${\beta}$-agarase. Thus, isolated bacterium and its ${\beta}$-agarase would be useful for the industrial production of neoagarotetraose and neoagarobiose.

• Journal of Photoscience
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• 제8권3_4호
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• pp.105-112
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• 2001

Susceptibility to low temperature photoinhibition in photosynthetic apparatus was compared among three cucumber cultivars, Gahachungjang (GH), Banbaekjijeo (BB) and Gaeryangsymji (GR). By chilling in the light for 6 h, a sustained decrease in the potential quantum yield (Fv/Fm) and the oxidizable P700 contents was observed, and the decrease was less in GH than in BB and GR. Although the difference was small, some $\Phi_{PSII}$ remained in GH after light-chilling for 6 h indicating that a few electrons can flow around photosystem II(PSII). As a consequence, the primary electron acceptor of PSII, $Q_{A}$, was reduced slowly and was not fully reduced after light-chilling for 6 h in GH. Although the amplitude was small, the development of NPQ was also faster in GH, indicating a higher capacity for non-photochemical energy dissipation. The relative fraction of a fast relaxing component of NPQ (qf) was higher in GH. After light-chilling for 5 h, the values of qf in BB and GR became much smaller than that in GH, indicating BB and GR suffered more significant uncoupling of ATPase and/or irreversible damages in PSII. When fluorescence induction transients were recorded after chilling, significant differences in quenching coefficients (qQ and qN) were observed among the three cultivars.

• 한국환경과학회지
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• 제9권3호
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• pp.185-191
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• 2000

Sustainable development has been the key concept, both in economic policies and in environmental management since 1970s. In the view of systems ecology, sustainable resource use strategies are considered to be essential in achieving sustainable development. During the last three decades, the discipline of systems ecology has applied ecological energetic analysis to the evaluation of the contribution of natural environments to economic systems. ENERGY analysis of main energy flows driving the economy of humans and life support systems of a city was made including environmental energies, fuel, and inputs, all expressed as solar emjoules. Total EMERGY use of Pusan was 3.89 E22 sej/yr, about 90 percent of it was purchased sources from outside during eleven years from 1985 to 1995. EMERGY flows from the environment were less than 10 percent. EMERGY yield ratio and environmental loading ratio were 1.10 and 10.45, respectively. EMERGY sustainability index is there(ore less than one, which is indicative of highly developed consumer oriented economies. Development of a city has been achieved in the short run by the economic growth, but it can be sustained in the long run by the use of renewable resource systems.

• 한국작물학회지
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• 제45권1호
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• pp.1-5
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• 2000

Leaf area is critical for crop light interception, and thereby has a substantial influence on crop yield. This experiment was conducted to characterize the development of soybean [Glycine max (L.) Merr.] leaf area. Plastochron index and leaf relative growth rate of Jackson was contrasted with the PI416937, which also has demonstrated tolerance to drought. First, plastochron ratio (PR) and plastochron index (PI) were evaluated in greenhouse to compare the leaf growth rate between two genotypes under well-watered condition. There was reasonable constancy of PR between two genotypes. The PR means of Jackson and PI416937 were 0.41 and 0.44, respectively. A fairly smooth increase of PI during vegetative stage was observed. Second, the relative growth rates were graphed against leaf area, normalized with respect to final leaf area, under well-watered and water-deficit conditions. Leaf growth was sustained longer in well-watered condition than water-deficit condition and there was a sizable proportion of leaves which was ceased earlier their growth in water-deficit condition compared to well-watered condition. The leaf relative growth rate of Jackson until leaves had completed at 45% of their growth during water deficit period was higher than that of PI416937.

• 약학회지
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• 제45권6호
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• pp.623-633
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• 2001

Various bupivacaine-loaded microspheres were prepared using poly(d,1-lactide) (PLA) and poly(d,1-lactic-co-glycolide) (PLGA) by a solvent evaporation method for the sustained release of drug. The effects of process conditions such as drug loading, polymer type and solvent type on the characteristics of microspheres were investigated. The prepared microspheres were characterized for their drug loading, size distribution, surface morphology and release kinetics. Drug loading efficiency and yield of PLGA micro- spheres were higher than those of PLA microspheres. The prepared microspheres had an average particle size below 5${\mu}{\textrm}{m}$. The particle size range of microspheres was 1.65~2.24${\mu}{\textrm}{m}$. As a result of SEM, the particle size of PLA microspheres was smaller than that of PLGA microspheres. In morphology studies, microspheres showed a spherical shape and smooth surface in all process conditions. In thermal analysis, bupivacaine-loaded microspheres showed no peaks originating from bupivacaine. This suggested that bupivacaine base was molecular-dispersed in the polymer matrix of microspheres. The release pattern of the drug from microspheres was evaluated for 96 hours. The initial burst release of bupivacaine base decreased with increasing the molecular weight of PLGA, and the drug from microspheres released slowly. In conclusion, bupivacaine-loaded microspheres were successfully prepared from poly(d,1-lactide) and poly (d,1- lactic-co-glycolide) polymers with different molecular weights allowing control of the release rate.

• 한국환경과학회지
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• 제2권2호
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• pp.135-144
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• 1993

The purpose of this experimental research was focused to improve the quality of the effluent and the yielded sludge when the papermill wastewater was treated by the indirect aerated submerged biofilter as a second treatment method of papermill wastewater. Changing the various experimental factors (Nutrient additions or not, HRT, Fh ratio, recirculation ratio, etc) with indirect aerated submerged biofilter, the results are as follows. 1) because of the microbes concentration could be sustained to 9, oho man in submerged biofilter and then the volumetric organic loads could be increased to 2.7 kg-BOD/$m^3$<\TEX>/day, the reactor volume can be reduced. 2) Because of the yield coefficient(Y) and the endogenous decay coefficient(kd) were revealed 0.4 and 0.07/d, the yielded sludge volume was reduced. 3) The concentration of the sloughed sludge in the reactor was 2.62~4.01 %, so the thickener could be omited in the papermill wastewater sludge treatment process. 4) When the operating was conducted at HRT of 4hrs, the treatment efficiencies of BOD and COD were obtained 80% and 70%. 5) The range of the theoretical recirculation ratios of this reactor was 14~26. According to those ratios, at the low loads ( BOD volumetric loads is less than 0.79 kg-BOD/$m^3$<\TEX>/day, FM ratio is less than 2.0/d) the results were fitted to the theoretical recirculation ratios (14 ~26) and at the high loads the efficiency were increased to the rise of recirculation ratios.

• 생물환경조절학회지
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• 제18권1호
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• pp.40-45
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• 2009

본 연구는 딸기 배양액의 $NO_3-N$와 $NH_4-N$의 비율을 달리하여 '장희(章姬)' 딸기의 생육, 수량 및 과실의 품질, 그리고 양이온 흡수에 미치는 영향을 알아보고자 수행하였다. $NO_3-N$와 $NH_4-N$의 비율은 5.5:0, 4.0:1.5, $3.0:2.5me{\cdot}L^{-1}$로 조절하였다. 실험기간 동안 배양액내의 $NH_4-N$의 비율이 높아질수록 pH가 낮았으며, EC는 전 실험기간 동안 $0.8{\sim}1.0dS{\cdot}m^{-1}$로 4월 이후에 5.5:0 처리구가 다른 처리구보다 약간 낮았으나 그 외에는 처리구 간에 유의한 차이를 나타내지 않았다. $NO_3-N:NH_4-N$를 3.0:2.5로 $NH_4-N$의 비율을 높여도 양이온의 흡수에 길항증상이 나타나지 않았다. 딸기의 엽병장과 엽폭은 $NO_3-N$의 단독 처리구 보다 $NO_3-N:NH_4-N$이 4.0:1.5와 3.0:2.5인 처리구에서 더 길어졌다. $NO_3-N:NH_4-N$이 4.0:1.5와 3.0:2.5 처리구 간에는 유의한 차이가 없었다. 과장, 과경, 과중, 당도는 $NO_3-N$와 $NH_4-N$비율 차이에 따른 통계적인 유의차가 인정되지 않았다. 주당 과실 수량은 $NO_3-N:NH_4-N$ 4.0:1.5의 처리구에서 가장 낮았으며, 나머지 두 처리간에는 유의한 차이가 없었다. 실험 기간 동안 이상과는 전혀 발생하지 않았다.

• 수산경영론집
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• 제22권2호
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• pp.75-99
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• 1991

A quantitative analysis was carried out to monitor the commercial yield level of walleye pollock Theragra chalcogramma in the east coast of Korea, based on available data on catch and fishing effort, catch per unit of effort including fish prices from 1911 to 1988, using a traditional yield model. The results from the quantitative assessment were based to estimate maximum economic yield (MEY) and optimal fishing effort (E-opt) at MEY. On the other hand, interaction aspects between danish seine fishery and trawl fishery mainly targeting walleye pollock in the east coast of Korea were studied to predict optimal situation in fishing effort level from economic point of view which gives the most benefits to the two fisheries. Total production of walleye pollock in 1911 when its catch record was begun for the first time was about 12, 000 metric tons(M/T), and then the catch trend maintained nearly at the level of 50, 000 M/T per annum, showing a decreasing trend until 1930. The highest production from historical data base on walleye pollock fishery statistics was from the years in 1939 and 1940, about 270, 000 M/T and 26, 000 M/T, respectively. No production of the fish species was recorded during the years from 1943 to 1947, and from 1949 to 1951. From 1952 onwards annual production was only available from the southern part of 38$^{\circ}$N in the east coast. During two decades from 1952 to 1970, the production had sustained about less than 30, 000 M/T every year. Annual production showed an increasing trend from 1971, reaching a maximum level of approximately 162, 000 M/T in 1981. Afterwards, it has deceased sharply year after year and amounted to 180, 000 M/T in 1988. The catch composition of walleye pollock for different fishery segments during 1970~1988 showed that more than 70% of the total catch was from danish seine fishery until 1977 but from 1978 onwards, the catch proportion did not differ from one another, accounting for the nearly same proportion. Catch per unit of effort (CPUE) for both danish seine fishery and trawl fishery maintained a decline tendency after 1977 when the values of CPUE were at level of 800 kg/haul for the former fishery and 1, 300 kg/haul for the latter fishery, respectively. CPUEs of gillnet fishery during 1980~1983 increased to about 3.5 times as high value as in the years, 1970~1979 and during 1987~1988 it decreased again to the level of the years, 1970~1978. The bottom longline fishery's CPUE wa at a very low level (20 kg/basket) through the whole study years, with exception of the value (60 kg/basket) in 1980. Fishing grounds of walleye pollock in the east coast of Korea showed a very limited distribution range. Danish seine fishery concentrated fishing around the coastal areas of Sokcho and Jumunjin during January~February and October~December. Distributions of fishing grounds of trawl fishery were the areas along the coastal regions in the central part of the east coast. Gillnet and bottom longline fisheries fished walleye pollock mainly in the areas of around Sokcho and Jumunjin during January~February and December. Relationship between CPUEs' values from danish seine fishery and trawl fishery was used to standardize fishing effort to apply to surplus production model for estimating maximum sustainable yield (MSY) and optimum fish effort (F-opt) at MSY. The results suggested a MSY of 114, 000 M/T with an estimated F-opt of 173, 000 hauls per year. Based on the estimates of MSY and F-opt, MEY was estimated to be about 94, 000 M/T with a range of 81, 000 to 103, 000 M/T and E-opt 100, 000 hauls per year with a range of 80, 000 to 120, 000 hauls. The estimated values of MEY and E-opt corresponded to 82% of MSY and 58% of F-opt, respectively. An optimal situation in the fishing effort level, which can envisage either simultaneously maximum yield or maximum benefit for both danish seine fishery and trawl fishery, was determined from relationship between revenue and cost of running the fleet : the optimal fishing effort of danish seine fishery was about 52, 000 hauls per year, corresponding to 50 danish seiners and 27, 000 hauls per year which is equal nearly to 36 trawlers, respectively. It was anticipated that the net income from sustainable yield estimated from the respective optimal fishing effort of the two fisheries will be about 3, 800 million won for danish seine fishery and 1, 000 million won for trawl fishery.

• 한국초지조사료학회지
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• 제7권2호
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• pp.71-78
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• 1987

본 실험은 파종방법, 배수화도 및 여름철 예취관리가 오차드그라스 채초지의 목장건물수량, 고사물량, 초지의 잡초발생 및 피복율에 미치는 영향을 조사하기 위하여 심험설계는 주구를 조파와 산파로 하고 세구를 배수랑호구와 배수불랑구로 하였으며, 세세구는 장마전 예취구와 장마후 예취구를 두어 세세구 배치 3반후으로 하여 1983년 9월부터 1984년 10월까지 실시하였던바 얻어진 결과는 다음과 같다. 1. 초지의 목장건물수량은 1회 예취시에는 처리간에 차이가 없었으나 2회와 3회 예취시에는 장마전 예취구가 장마후 예취구에 비하여 수량이 높았고 ($P{\le}0.01$) 3회예취시에는 조파구가 산파구에 비하여 수량이 높았다. $P{\le}0.05$. 2. 목장의 고사물량은 2회예취시에만 발생하였는데 장마전 예취구에서는 발생하지 않았는데 반해 장마후 예취구에서는 배수랑호구와 배수불랑구에서 총 목장수량에 대하여 각각 24%와 35%의 고사물량이 발생하였다. 3. 잡초발생은 1회, 2회예취시에는 거의 없었으나 3회 예취시부터 다량발생하였는데 산파구가 조파구에 비하여 높았고 ($P{\le}0.05$) 장마후 예취구가 장마전 예취구에 비하여 월등이 높았다. $P{\le}0.01$. 4. 목장의 피복율은 1회 예취율에는 거의 100%로 차이가 없었으나 2회 및 3회 예취후에는 장마전 예취구가 장마후 예취구에 비하여 매우 높은 수준을 보였으며 ($P{\le}0.01$) 조파는 산파에 비하여 높았으나 유의차는 없었다. 또한 각 처리구의 월동전식생 피복율은 장마전 예취구는 장마후 예취구에 비해 오차드그라스의 구성비율은 높았고 잡초 및 나지의 구성비율은 낮았다. 5. 본 실험결과로 미루어보아 오차드그라스채초지의 2회 예취는 장마전에 실시하고 조파를 함으로서 잡초발생을 크게 줄일 수 있을 것으로 생각된다.

• KSBB Journal
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• 제16권5호
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• pp.505-510
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• 2001

생분해성 합성고분자인 PLA와 천연고분자 물질 tamarind gum과 levan을 불용화시킨 다당 아세타이트를 solvent evaporation 방법을 통해 약물(indomethacin)이 포함된 미세구를 제조하였다. PLA 미세구의 경우, 약물의 방출속도는 함유된 약물의 양에 따라 달라졌으며 담체의 비율이 증가할수록 약물의 방출이 지연되었다. 다당 아세테이트를 이용해서 제조한 미세구의 경우에도 방출지연 효과가 있었다. 이러한 점들을 고려해볼 때 본 실험에서 사용한 생체분해성 고분자 미세구들이 방출지연담체로 사용될수 있음을 알 수 있었다.