• Journal of Ecology and Environment
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• 제33권3호
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• pp.195-204
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• 2010

In the study, the effects of elevated $CO_2$ and temperature on the photosynthetic characteristics, chlorophyll content, nitrogen content, carbon content, and C/N ratio of Phytolacca insularis and Phytolacca americana were examined under control (ambient $CO_2+$ ambient temperature) and treatment (elevated $CO_2+$ elevated temperature) for 2 years (2008 and 2009). The photosynthetic rate, transpiration rate and water use efficiency of two plant species were higher under the treatment than the under the control. The stomatal conductance of P. insularis was higher under the control, but that of P. americana was not significantly affected by $CO_2$ and temperature under the treatment. The chlorophyll contents of two species were decreased about 72.5% and 20%, respectively, by elevated $CO_2$ and temperature. The nitrogen contents of two species were not significantly altered by increase in $CO_2$ and temperature. The carbon contents of the two species were higher under the treatment than under the control. The C/N ratio of P. insularis was higher under the treatment but that of P. americana was not significantly affected by $CO_2$ and temperature. These results demonstrated that the physiological responses of P. insularis native plants might be more sensitively influenced by a $CO_2$-mediated global warming situation than those of the P. americana invasive plants.

• 생물환경조절학회지
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• 제1권1호
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• pp.21-27
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• 1992

야온과 시용질소의 형태를 달리한 양액이 탑채와 백경채의 생육 및 품질에 미치는 영향을 알아보기 위하여 실시한 실험의 결과는 다음과 같다. 1. 탑채, 백경채 모두 야온 15$^{\circ}C$ 에서 생육이 왕성하여 생체중이 무거웠으나 건물율과 vitamin C의 함량은 온도가 낮아질수록 증가하였다. 2. 양액의 N형태 비율에 따른 백경채의 생육은 NO$_3$$^{-}$ : NH$_4$$^{+}$ 의 비가 0 : 8에서만 극히 생육이 저조하고, 다른 처리구에서는 큰 차이가 없었다. 3. 양액내 NO$_3$$^{-}$-N의 함량이 높을수록 vitamin C의 함량이 많고, NH$_4$$^{+}$-N의 함량이 높을 때는 건물율이 높았다.

• 제어로봇시스템학회논문지
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• 제20권8호
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• pp.890-894
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• 2014

In this paper, we derive the CRLB (Cramer-Rao Lower Bound) of effective carrier-to-noise power ratio ($C/N_0$) estimation for a GPS (Global Positioning System) L1 C/A (Coarse/Acquisition) signal under band-limited white noise jamming environments. The quality of a received GPS signal is commonly described in terms of its $C/N_0$, implying that the noise is white and thus can be described by scalar noise density. However, if some intentional interference is received to a victim GPS receiver, then the $C/N_0$ is no longer the efficacious performance indicator. The correct and straightforward measurement to analyze the receiving situation is the effective $C/N_0$. In this paper, we consider a band-limited white noise jamming whose bandwidth is 2MHz and is the same as one of the first null-to-null bandwidth of the GPS L1 C/A signal.

• 산업기술연구
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• 제13권
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• pp.3-17
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• 1993

The composting process is a suitable to dispose the livestock manure in terms of resources recovery. However the performence of composting process is greatly affected by the environmental conditions such as characteristics of manure, type of the bulking agent, initial moisture contents, temperature, recycle and so on. The purpose of this study is to evaluate the optimum environmental conditions of composting process for livestock manures. The analytical results indicated that no bulking agent was necessary for the cow manure because of the proper C/N ratio. However the pig manure required a bulking agent since the pig manure had not only low in C/N ration but poor ventilation characteristics. In addtion, the initial miosture content for optimum composting appeared to be about 60%. The temperature control was also an essential factor to enhance the activity of thermophilic microorganisms in the laboratory composting unit. It was further found that the recycle of composts may contributed the completion of composting precess as well as C/N ratio reduction and moisture control.

• 한국응용과학기술학회지
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• 제35권3호
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• pp.654-666
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• 2018

본 연구는 비만 모델동물 랫드에서 식이 내 오메가 6와 3 지방산 비율(n-6/n-3 0, 4:1, 15:1, 30:1)이 지질대사의 생화학적 메카니즘을 구명하였다. 혈액 중성지방은 대조군과 비교할 때 n-6/n-3 비율 4:1, 15;1, 30:1 처리군에서 22.21%, 총콜레스테롤 20.60%, LDL-C 52.96%, 혈당 15.71%, ALT 11.97%, AST 9.13%, 인슐린 37.57%, 렙틴 45.98% 낮아졌으나, HDL-C 28.38%, 인지질 80.39% 증가하였고, 특히 4:1 처리군에서 가장 큰 효과가 나타났다. 간 조직에서 SREPB-$1{\alpha}$, SREPB-2 mRNA는 대조군과 비교할 때 n-6/n-3 비율 처리군에서 하향조절 하였으나 PPARs 그리고 지방조직의 LPL-mRNA는 상향조절 하였다. 간 조직에서 지방세포의 크기는 n-6/n-3 비율 30:1, 대조군, 15:1, 4:1 순서로 낮아졌고, 지방조직에서 지방세포의 크기는 대조군, 30:1, 15:1, 4:1 순서로 낮았다. 결과는 비만 모델동물 랫드에서 오메가 6와 오메가 3 지방산 비율, 특히 4:1을 함유하는 식이를 급여하면 혈액 유해 지질, 간 기능 효소, 렙틴, 인슐린, 간과 지방조직의 유전자 발현 조절을 통하여 건강을 유지할 수 있다는 새로운 사실을 발견하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제22권9호
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• pp.1248-1255
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• 2009

This study was carried out to evaluate the fatty acid composition in Nellore cows supplemented with either linseed (n-3) or canola grains (n-6 and n-9). Fifteen Nellore cows, aged five years and bodyweight 550 kg${\pm}$48 kg, were randomly distributed to the following treatments: CON (control), LIN (linseed) and CAN (canola grains). The cows were fed for 80 days. The concentrations of C18:0, C18:2 n-6 and C20:3 n-6 fatty acid were higher (p<0.10) in CON blood plasma in comparison to follicular liquid. Likewise, PUFA, n-6 contents, PUFA:SFA and n-6:n-3 ratios were higher (p<0.10) in blood plasma. On the other hand, C18:1 n-9, C22:5 n-3, MUFA and n-3 contents were lower (p<0.10) in blood plasma. C18:0, C18:2 n-6, C18:3 n-3, C22:5 n-3, PUFA, n-6, n-3 contents and PUFA:SFA ratio were higher (p<0.10) in LIN blood plasma than in the follicular liquid. Nevertheless, C14:0, C16:0, C16:1 n-7, PUFA, C16:0, C18:1 n-9 and MUFA contents were lower (p<0.10) in LIN blood plasma. On treatment CAN, the C18:0 and SFA contents, and n-6:n-3 ratios were higher (p<0.10) in blood plasma. However, C20:3 n-6, C22:5 n-3, PUFA and n-3 contents were lower (p<0.10) in blood plasma. C16:0, C18:0, PUFA, SFA contents and PUFA:SFA ratio did not differ (p>0.10) among the treatments. C14:0, C16:1 n-7, C18:2 n-6 and n-6 contents were higher (p<0.10) for CON and CAN than LIN. C17:1 n-7, C20:4 n-6 and C 22:0 contents were higher (p<0.10) for CAN than CON and LIN. C18:1 n-9, C18:3 n-3, MUFA and n-3 contents were higher (p<0.10) for LIN and CAN than CON. C20:3 n-6 content and n-6:n-3 ratio were higher (p<0.10) for CON than LIN and CAN. C22:5 n-3 content were higher (p<0.10) for CON and LIN than CAN. The concentrations of fatty acids in blood plasma and follicular liquid were not correlated for any fatty acid, independent of the treatment studied. Canola grain added to the diet of Nellore cows resulted in increased concentrations of fatty acids n-6 and n-3 in follicular liquid.

• 한국물환경학회지
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• 제22권2호
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• pp.230-237
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• 2006

The operational parameters and control strategies of a tertiary wastewater treatment process a biological filtration system were investigated. The biological filtration system consisted of a nitrification filter (Fiter 1) and a polishing filter with anoxic and aerobic parts (Filter 2). SS, T-C-BOD, and T-N in effluent were kept stable at less than 3, 5 mg/L, and 5 mgN/L, respectively, under a HRT in Filter (filter-bed) of 0.37~2.3 h. T-N at the outlet of Filter 2 were about 1~5 mgN/L under the condition of LV of 50~202 m/d. Methanol addition was controlled based on the COD/N ratio or McCarty's equation. Constant COD/N ratio control results in excess addition under large diurnal fluctuation of $NOx^--N$, and McCarty's equation can be used to add appropriate amount of methanol. Control of methanol addition by on-line nitrate measurement, control of aeration by on-line DO measurement, and control of backwashing by head loss measurement are successfully operated. These results proved that this process prove the easy-maintenance and cost-effectively treatment is attainable.

• 환경생물
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• 제31권4호
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• pp.383-392
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• 2013

본 연구는 식물성 플랑크톤의 1차 생산력에 대한 N:P ratio의 영향을 분석하기 위해 "영양염 첨가실험(NEBs)"을 실시하였다. 영양염 첨가실험(NEBs)에 의한 N:P Ratio의 영향은 대청호에서 측정된 수질데이터와 비교분석하였다. 단기 영양염 첨가실험 결과, 인 (P)을 첨가한 처리군들 (N:P Ratio=5, 15, 20, 30)에서의 1차 생산력의 반응이 대조군 (Control)과 인(P)을 첨가한 처리군 (N:P Ratio=80, $T_V$), 질소(N)를 첨가한 처리군(N:P Ratio=150, $T_{VI}$)에서보다 높았다. 또한 질소 (N)를 처리한 처리군에서는 대조군과 모든 처리군에서보다 1차 생산력의 반응이 유의하게 작았다. 영양염 첨가실험의 결과, 식물성 플랑크톤의 성장에 인이 제한영양염으로 작용하고 있었으며, 질소첨가 (Spiking N)는 식물성 플랑크톤의 성장을 억제한 것으로 사료된다. 대청호의 영양염 변이 분석 결과, 최소 N:P Ratio에서 엽록소-a의 최대농도가 나타났고, N:P Ratio는 식물성 플랑크톤의 성장에 대한 핵심 조절자로 사료되었다. 본 연구결과를 종합해 볼 때, N:P Ratio가 식물성 플랑크톤의 성장을 조절하는 핵심 인자로 작용 할 것으로 사료된다.

• 한국환경농학회지
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• 제28권4호
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• pp.397-402
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• 2009

In Korea, salt stress is one of the major problems limiting crop production and eco-environmental quality in greenhouse soil. The objective of this study was to evaluate the effectiveness of organic residues (Chinese milk vetch, maize stalk, rice straw, and rye straw) for reducing salt activity in greenhouse soil. Organic residues was incorporated with salt-accumulated soil (EC, 3.0 dS $m^{-1}$) at the rate of 5% (wt $wt^{-1}$) and the changes of electrical conductivity (EC) was determined weekly for 8 weeks under incubation condition at $30^{\circ}C$. The EC, microbial biomass carbon (MBC), and water soluble ions in soil was strongly affected by C/N ratio of organic residues. After 8 weeks incubation, the concentration of water soluble $NO_3{^-},\;Ca^{2+}$, and $Mg^{2+}$ was significantly decreased in organic residues having high C/N ratio (maize stalk, rice straw, and rye straw) incorporated soil compared to organic residues having lower C/N ratio (Chinese milk vetch) incorporated soil. The EC value in Chinese milk vetch incorporated soil was higher than control treatment. In contrast, maize stalk, rice straw, and rye straw amended soil was highly decreased the EC value compared to control and Chinese milk vetch applied soil after 4 weeks incubation. Our results indicated that incorporation of organic residues having high C/N ratio (>30) could reduce salt activity resulting from reducing concentration of water soluble ions.

• 한국환경보건학회지
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• 제28권2호
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• pp.141-148
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• 2002

This study was performed to examine the effects of rice straw as bulking materials on temperature, pH, weight and volume reduction, porosity, C/N ratio, salinity, and conductivity in aerobic composting of food wastes. Volume ratios of food wastes to rice straw in reactor control, RS-1, RS-2, RS-2 and RS-4 were 4:0, 4:1. 4:2. 4:3 and 4:4, respectively. Reactors were operated for 24days with 1 hour stirring by lrpm and 2hours aeration per day. The values of pH of food wastes and rice straw were 4.39 and 7.4, respectively. The lowering of the volume ratio of food wastes to rice straw resulted in the high reaction temperature and the fast weight and volume reduction rates. C/N ratio in control was larger than that in rice straw containing reactors. Salinity and conductivity in reactors were condensed and increased by reaction days.