• Korean Journal of Weed Science
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• v.10 no.2
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• pp.93-98
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• 1990

Interspecific competition between E. colona and rice was determined over four growth stages in replacement series. No competition between the two species as measured by plant height, leaf area and dry weight occurred by 30 days after seeding (DAS) at all the density combinations studied. At 45 DAS reductions in leaf area and dry weight of E. colons due to the competition occurred at the density combinations where number of competing E. colons plant was less than that of rice. However, there was a great increase in leaf area and dry weight of E. colons at the density combination of one E. colons competing with four rice plants at 60 DAS. As the number of E. colons plants increased, the leaf area and dry weight of E. colona decreased resulting from intraspecific competition between E. colons plants. Although rice absorbed more nitrogen than E. colons up to 30 DAS, the reverse was observed from 45 DAS. A relatively small amount of phosphorous was absorbed by both rice and E. colons, but the amount of phosphorous taken up by E. colons was greater than that taken up by rice. E. colons absorbed extremely high amount of potassium when compared to rice.

• Journal of Animal Environmental Science
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• v.17 no.3
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• pp.181-188
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• 2011

With an increasing livestock population, animal manure production has been steadily increasing in Korea. This trend has forced farmers to spend more money for animal manure treatment in their farm. Therefore, research utilizing animal manure as a renewable resources has become increasingly important. The purpose of this study was to develop a stable advanced wastewater treatment system can be applied to conventional animal wastewater treatment processes and evaluate its contribution to reduce effluent discharge volume by recycling as flushing water. AOP (advanced oxidation process) process improved wastewater treatment efficiency in terms of color, suspended solids (SS) and chemical oxygen demand (COD). Due to the addition of Hydrogen peroxide ($H_2O_2$), pathogens, Salmonella and E. coli, reduction was accomplished. To enhance ozone treatment effect, three levels of ozone test on secondary effluent of pig slurry purification system were conducted. At the level of 5 g/hr, 6.7 g/hr and 8.4 g/hr color of secondary effluent of pig slurry purification system were decreased from 2,433 to 2,199, 2,433 to 1,980 and 2,433 to 243, respectively.

• Applied Biological Chemistry
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• v.41 no.2
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• pp.175-180
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• 1998

As a part of investigation for quality improvement of surimi gel from fish with a red muscle by addition of calcium-based powder from fish bone, we investigated the processing condition of calcium-fortified mackerel surumi gel and its quality stability during storage at $5^{\circ}C$. Judging from the results of the soluble calcium content and jelly strength, the reasonable addition concentration of calcium-based powder from Alaska pollack bone for improvement of functional properties in surimi gel was revealed 0.9% on the weight basis of the chopped mackerel meat. The soluble calcium content of the calcium-fortified surimi gel (105.0 mg/100 g) was more than that of the ordinary surumi gel (2.9 mg/100 g). During cold storage of calcium-fortified surumi gel, the moisture contents, amino acid compositions, soluble calcium and phosphorus contents were little changed, the pH, volatile basic nitrogen contents, histamine contents, peroxide values and brown pigment formation were slightly increased and viable cell counts and coliform groups were not detected. The calcium-fortified surimi gel was superior in the lysine and calcium contents, EPA and DHA compositions to the ordinary surumi gel. Judging from the results, it was suggested that calcium-fortified surumi gel was nutritive, functional and safety foods.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.62-68
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• 1998

To develop methods to produce low salt fermented squid with rich flavor and acceptable shelf life, the optimum processing conditions such as water activity of raw material, amounts of NaCl, papain and gucose were investigated. Water activity of squid meat was adjusted to 0.94 (raw meat), 0.90 and 0.88 by cold air blast and each was salted with 3, 5, or 7% NaCl followed by fermenting at $10^{\circ}C$ for 6 weeks. Amino nitrogen was increased rapidly with high water activity and low NaCl concentration. As a result of organoleptic evaluation it was concluded that optimum conditions were to adjust water activity of raw material to 0.90 and to salt with 5% NaCl. When squid meat adjusting water activity to 0.90 was treated with 0.05, 0.1 and 0.5% papain and fermented at $10^{\circ}C$ for 6 weeks, SDS-PAGE pattern showed rapid breakdown of myofibrilar protein with increasing amounts of papain but the treatment with 0.1% enzyme was best organoleptically. pH values of squid meat added with 1 and 2% glucose were maintained lower than control (glucose 0%) but there were no significant differences between the two glucose treatments. Therefore, it was thought that adding of glucose might be extended shelf life of fermented squid with low salt concentration.

• Journal of Aquaculture
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• v.10 no.2
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• pp.105-112
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• 1997

For improvement of fishermen's income by oyster cultivation in eastern coast of Korea, the spats of oyster (Crassostrea gigas) collected from Hadong in southern coast of Korea were transplanted to Chumunjin and cultured by hanging long line method from August 1994 to July 1995 for examination of their growth and ground environmental conditions. The environmental conditions show the annual range of water temperature as 8.33~$25.62^{\circ}C$, salinity as 32.84~$34.28\textperthousand$, PO4-P as 0.09~0.40$\mu$g-at/1, dissolived inorganic nitrogen (DIN) as 0.32~3.21$\mu$g-at/1. The growth of oyster in hanging culture was as follows : 88.7mm (shell hight) in upper layer (7m), 84.9mm in middle layer (10m) and 78.0mm in lower layer (13m) after one-year cultivation. Thus, the oysters in upper layer had grown relatively faster than those in lower layer. The relationships between shell hight (SH) and shell length (SL) in each culturing depth as follows : SL=0.5403 SH+8.5486 (r=0.9959) in upper layer, SL=0.5813 SH+3.7775 (r=0.9869) in middle layer, and SL=0.5159 SH+6.8736 (r=0.9961) in lower layer. The meat weight of oyster was the highest value as 13.24g in upper layer, and 12.68g in middle layer, and lowest as 10.96g in lower layer. The relationships between total wight (TW) and meat weight (MW) with culturing water layer were as follows : MW=0.1933 TW+0.1051 (r=0.0073) in upper layer, MW=0.1915 TW+0.1894 (r=0.9984) in middle layer, and MW=0.1650 TW+0.0558 (r=0.9983) in lower layer.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.2
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• pp.109-113
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• 2009

This study was performed to investigate the characteristics of nutrient removal of municipal wastewater in membrane bioreactor system. Membrane bioreactor consists of four reactors such as the anaerobic, the stabilization, the anoxic and the submerged membrane aerobic reactor with two internal recycles. The hydraulic retention time (HRT), sludge retention time (SRT) and flux were 6.2 h, 34.1 days and 19.6 L/$m^2$/hr (LMH), respectively. The removal efficiency of $COD_{Cr}$, SS, TN and TP were 94.3%, 99.9%, 69.4%, and 74.6%, respectively. The estimated true biomass yield, specific denitrification rate (SDNR), specific nitrification rate (SNR), specific phosphorus release rate (SPRR) and specific phosphorus uptake rate (SPUR) were 0.653 kgVSS/kgBOD/d, 0.044 $mgNO_3$-N/mgVSS/d, 0.035 $mgNH_4$-N/mgVSS/d, 51.0 mgP/gVSS/d and 5.4 mgP/gVSS/d, respectively. The contents of nitrogen and phosphorus of biomass were 8.86% and 3.5% on an average.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.10
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• pp.583-589
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• 2015

This study was performed to evaluate the feasibility of anaerobic pretreatment for the leachate solubilized from thermal hydrolysis of sewage sludge cake. Overall process for the treatment of sludge cake consists of thermal hydrolysis, crystallization of magnesium, ammonium, and phosphate (MAP) for the leachate and anaerobic digestion of supernatant from MAP crystallization. The experimental evidence showed that the optimum ratio of Mg : P for the struvite crystallization of leachate solubilized from thermal hydrolysis of sludge cake was 1.5 to 1.0 as weight basis at the pH of 9.5. With this operational condition, the removal efficiencies of ammonia nitrogen and phosphorous achieved 50% and 97%, respectively. The mesophilic batch test showed that the ultimate biodegradability of the supernatant from MAP crystallization reached 63% at S/I ratio of 0.5. The readily biodegradable fraction of 90% ($S_1$) of the MAP supernatant BVS (Biodegradable Volatile Solids, $S_0$) degraded with $k_1$ of $0.207day^{-1}$ for the initial 17 days where as the rest slowly biodegradable fraction ($S_2$) of 10% of BVS degraded with $k_2$ of $0.02day^{-1}$ for the rest of the operational period. Semi-Continuously Fed and Mixed Reactor (SCFMR) was chosen as one of the best candidates to treat the MAP supernatant because of its total solids content over 6%. Maximum average biogas production rates reached 0.45 v/v-d and TVS removal efficiency of 37~41% was achieved at an hydraulic retention time (HRT) of 20 days and its corresponding organic loading rate (OLR) of 1.43 g VS/L-d.

• Journal of the Korean Applied Science and Technology
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• v.33 no.4
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• pp.836-847
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• 2016

Water soluble oil was obtained by pyrolysis of biomass. The characteristics of emulsified fuel by mixing water soluble oil and MDO(marine diesel oil) and engine emissions were studied with engine dynamometer. Saw dust was used as biomass. Water soluble oil was obtained by condensing of water and carbon content with pyrolysis of saw dust at $500^{\circ}C$. Emulsion fuel was obtained by emulsifying MDO and water soluble oil by the water soluble oil mixing ratio of 10 to 20% of MDO. Exhaust gas detection was performed with engine dynamometer. While combustion, micro-explosion took place in the combustion chamber by water in the emulsion fuel, emulsion fuel scattered to micro particles and it caused to smoke reduction. The heat produced from water vapour reduce the temperature of internal combustion chamber and it caused to inhibition of NOx production. It can be verified by the lower exhaust temperature of each ND-13 mode using emulsion fuel than that of MDO fuel. The NOx and smoke concentration were reduced by increasing water soluble oil content in the emulsion fuel. The power also decreased according to the increment of water soluble oil content of emulsion fuel because emulsion fuel has low calorific value due to high water content than MDO. As a result of ND-13 mode test with 20% bio oil content, it was achieved 25% reduction in NOx production, 60% reduction in smoke density, and 15% reduction in power loss.

• Journal of The Korean Society of Grassland and Forage Science
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• v.12 no.3
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• pp.64-129
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• 1992

최근 초지중심 사양형태의 증가와 초지면적의 확대에 따라 단순한 사료로서가 아니라 영양가치가 높고 기호성이 높은 목초생산이 요구되고 있다. 그러나, 고위생산을 위해 다량으로 사용된 질소질비료에 의하여 질산태 중독 등의 문제가 야기되고 있어 목초의 생리 및 영양에 관한 연구가 필요하게 되었다. 사료성분 혹은 영양가치에 대한 연구는 이미 일찍부터 다루어져 왔으나, 주로 야초류, 청예작물 및 농가부산물 등의 일반성분 특히, 조단백질과 조섬유함량의 연구가 주가 되었고 다년생 목초류에 대한 연구는 1975년경부터 본격화 되기 시작하였다. 그동안 한국초지학회지와 축산학회지($1972\sim1991$)에 게재된 총 151편의 생리 및 영양에 관한 연구 중에서 다년생 목초류를 취급한 것은 불과 63편에 머물고 있다. 이 분야의 연구는 각종 목초 사료작물에 대한 재배조건과 생육단계에 따른 생리생태학적 연구와 사료성분, 소화율 및 가소화양분 함량의 일반적인 변화, 경향을 검토하여 사료 가치 평가를 위한 기준으로 삼았다. 그러나 다년생 목초류는 물론 사료 작물에 있어서 육종 생리분야의 연구는 매우 미흡한 상태로써 단지 발아, 생육, 저장탄수화물 및 유독성분 등 단편적인 연구만이 행해지고 있을 뿐이다. 또한 사료 성분이 가축의 기호성에 미치는 영향을 구명하기 위한 연구는 거의 이루어지고 있지 않으므로 금후 탄수화물과 미량 요소에 대한 자세한 연구 검토가 필요하다고 생각된다. 특히 목초와 사료작물의 화학적인 조성과 가축의 생리에 관련한 여러가지 문제들도 앞으로 보다 깊이 연구되어야 할 과제라고 생각된다.권을 잡기 위해 10년지기였던 IBM과 MS사는 각각 OS/2와 윈도즈를 내세우고 양보할 수 없는 힘겨루기에 들어갔다. 또 이들 양사는 펜컴퓨터,멀티미디어등 차세대제품의 운영체제 시장을 둘러싸고 일찍부터 격전에 들어갔으며 IBM과 MS사의 혼전을 틈타 썬마이크로시스템을 필두로한 워크스테이션 업체 및 유닉스진영까지 고성능 PC시장을 겨냥한 OS를 속속 개발, 90년대의 OS 전쟁은 한치 앞을 내다볼 수 없는 안개국면으로 접어들고 있다. DOS에서 32비트시대,펜컴퓨터, 멀티미디어에 이르는 차세대제품을 둘러싼 업계의 OS 쟁탈전을 통해 OS의 발전동향과 미래를 전망해 본다. results in the large change of the objective function, the sum of squares of deviations of the observed and computed groundwater levels. 본 논문에서는 가파른 산사면에서 산사태의 발생을 예측하기 위한 수문학적 인 지하수 흐름 모델을 개발하였다. 이 모델은 물리적인 개념에 기본하였으며, Lumped-parameter를 이용하였다. 개발된 지하수 흐름 모델은 두 모델을 조합하여 구성되어 있으며, 비포화대 흐름을 위해서는 수정된 abcd 모델을, 포화대 흐름에 대해서는 시간 지체 효과를 고려할 수 있는 선형 저수지 모델을 이용하였다. 지하수 흐름 모델은 토층의 두께, 산사면의 경사각, 포화투수계수, 잠재 증발산 량과 같은 불확실한 상수들과 a, b, c, 그리고 K와 같은 자유모델변수들을 가진다. 자유모델변수들은 유입-유출 자료들로부터 평가할 수

• Applied Biological Chemistry
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• v.47 no.2
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• pp.208-215
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• 2004

As a part of a study on the effective use of cultured oyster, oyster powder-added soybean pastes were prepared and its characteristics were examined. As the concentration of oyster powder added to commercial soybean paste was increased, the moisture level decreased, the crude and amino nitrogen content increased with no change in the salinity and titratable acidities. Also, the color of the soybean paste changed to a darker color as the concentration of oyster powder added to commercial soybean paste increased. Judging from the results of the above experiment and sensory evaluation, the optimal additive concentration of oyster powder to commercial soybean paste was revealed as 9%. The total amino acid content of oyster powder-added soybean paste was 2% higher than that of commercial soybean paste. The ratio of calcium and phosphorus of oyster powder-added soybean paste was about 1:2-2:1, an improvement in calcium absorption as compared to commercial soybean paste. Functional fatty acids, such as 20:5n-3 and 22:6n-3, were not detected in commercial soybean paste but detected in oyster powder-added soybean paste. The major free amino acids in oyster powder-added soybean paste were glutamic acid and aspartic acids. According to the above results, the nutritional, functional and taste properties of commercial soybean paste were improved while reducing preparation time of the housewife.