• 생명과학회지
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• 제20권9호
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• pp.1415-1419
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• 2010

최근 웰빙 열풍으로 나날이 녹차에 대한 관심과 소비가 증가하고, 생산 재배되고 있는 산지에 대한 브랜드화가 진행되고 있다. 하지만 지역에서 재배되고 있는 녹차품종의 구별 및 차이에 대해서는 아직 많은 연구가 되어 있지 않고 있다. 이 연구에서 국내 대표 녹차산지인 하동지역과 보성지역에서 채집한 녹차와 중국과 일본의 대표적 녹차품종을 가지고 STS-RFLP분석을 수행하였다. 페닐프로파노이드 생합성 경로에 관여하는 페닐알라닌 암모니아 리아제와 찰콘 합성효소 그리고 디하이드로플라보놀 4-리덕타아제 유전자의 암호영역과 비암호영역을 사용하여 이들 품종들을 구별할 수 있는 연구에 성공하였다. 이 논문에서는 녹차품종 구별에 사용 가능한 STS-RFLP법과 프라이머를 나타내었고, 하동지역과 보성지역의 녹차품종을 CHS 유전자의 CAPS 마커만으로 구별할 수 있는 방법을 찾아내어, 국내 지역간 품종의 구분 및 검증에 사용할 수 있다는 사실을 제시하였다.

• 한국물환경학회지
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• 제21권5호
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• pp.448-457
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• 2005

The conventional activated sludge processes were operated as a combined organic substrate removal and nitrification. So, it was necessary to provide with oxygen for both carbon and ammonia removal. But, in the BNR processes, nitrification is separated from carbon removal that causes fast ammonia oxidation and reduced oxygen demands. And most of the substrate is utilized by denitrification organisms and phosphorus accumulating organisms. with these appearances, mathematical model for BNR processes different from IWA ASM can be simplified and applied. In this study, it was performed that the existing equations as McKinney model, nitrification model published by U.S. EPA and oxygen demands from stoichiometry and the relationship between NUR and OUR were applied to full-scale BNR processes and the results were compared with the measured. and it is possible to make out the optimum design parameter from those equations.

• Environmental Engineering Research
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• 제25권2호
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• pp.135-146
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• 2020

This study was aimed to investigate the possibility of using raw and anaerobically-digested piggery wastewater as culture media for a green microalga Chlorella vulgaris (C. vulgaris). Due to high concentration of ammonia and dark color, the microalga did not grow well in this wastewater. In order to solve this problem, air stripping and NaOCl-treatment were applied to reduce the concentration of NH₃-N and the color intensity from the wastewater. Algal growth was monitored in terms of specific growth rate, biomass productivity, and nutrient removal efficiency. As a result, C. vulgaris grew without any sign of inhibition in air-stripped and 10-folds diluted anaerobically-digested piggery wastewater with enhanced biomass productivity of 0.57 g/L·d and nutrient removal of 98.7-99.8% for NH₃-N and 41.0-62.5% for total phosphorus. However, NaOCl-treatment showed no significant effect on growth of C. vulgaris, although dark color was removed greatly. Interestingly, despite that the soluble organic concentration after air stripping was still high, the biomass productivity was 4.4 times higher than BG-11. Moreover, air stripping was identically effective for raw piggery wastewater as for anaerobic digestate. Therefore, it was concluded that air stripping was a very effective method for culturing microalgae and removing nutrients from raw and anaerobically-digested piggery wastewaters.

• 한국초지조사료학회지
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• 제7권3호
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• pp.153-156
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• 1987

본 실험은 이른봄에 많이 생산이용되고 있는 호맥을 수영기, 출영기, 유숙기, 호숙기 및 황숙기의 5단계로 예취하여 이들을 임과로 silage를 만들었을 때 그 품질을 분석비교한 것으로써 그 결과를 요약하면 다음과 같다. 1. Silage의 건물회수율은 난숙기부터 높아졌고 (P<0.01), Total-N에 대한 ammonia 태실표의 비율은 난숙기(9.37%)와 호숙기(12.7%)가 낮았다. (P<0.01). 2.Silage의 건물과 건물회수율 및 건물과 pH의 상관관계는 각각 0.782및 0.785로서 정(+)의 상관이 있었고(P<0.01), 건물회수율과 수분 및 $NH_3-N$간에는 차(일)의 상관이 있었다 (P<0.05). 3. 생율단계별 silage의 유기산함량에 의한 품질평가로서는 난숙기와 호숙기가 우수한 것으로 나타났다. 4. 호맥은 수량과 silage의 품질면에서 볼 때 호숙기에 예취하여 silage로 이용하는 것이 가장 적합하다고 사료된다.

• KSBB Journal
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• 제14권3호
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• pp.328-336
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• 1999

본 연구에서는 제철소에서 배출되는 산업폐수를 이용하여 미세조류를 성공적으로 배양하였으며 이에 대한 모델링 연구를 통해 이산화탄소의 고정화 및 암모니아의 제거효율에 미치는 환경인자에 대하여 살펴보고 실제 옥외배양에서의 성능을 평가하고자 하였다. Bottle에서의 배양을 통해 산업폐수에서 미세조류가 성장하면서 암모니아를 완전히 제거할 수 있음을 확인하였다. 또한 이때 타양미생물의 성장은 미세조류의 성장에 비해 미미하였으므로 건조중량으로부터 고정화된 이산화탄소를 계산할 수 있었다. Raceway pond의 회분식운전 결과로부터 조류성장에 대한 모델을 구축하고 관계되는 parameter를 결정할 수 있었으며 이로부터 실제 옥외에서의 빛의 세기에서 고정화된 이산화탄소의 누적량 및 암모니아의 제거를 계산할 수 있었다. 그 결과 60 klux이상의 빛에서는 암모니아가 완전히 제거될 수 있다는 결과를 얻었으며 빛의 세기가 증가할 수록 성능이 향상되지만 빛에너지에 대한 효율은 감소하는 경향을 발견하였다. Raceway pond의 실제 옥외운전을 모사하기 위한 반연속식 배양실험에서는 dilution rate이 증가할 때 이산화탄소의 고정화율 및 암모니아의 제거율이 증가하나 암모니의 제거효율은 감소하는 경향을 얻었다. 또한 raceway pond의 옥외배양시 빛의 세기 및 폐수의 깊이, dilution rate에 따른 성능변화를 모델로 이용하여 계산하였는데 결과적으로 하루에 12시간동안 100klux의 태양빛이 공급되는 조건에서 raceway pond를 운전할 때 최적의 dilution rate은 0.425$day^{-1}$이며 이러한 조건에서 24.7 g$m^{2}day^{-1}$의 속도로 이산화탄소를 고정할 수 있는 것으로 평가되었다. 또한 이러한 조건에서 암모니아는 0.52 g $NH_3-Nm^{-2}day^{-1}$의 속도로 제거될 수 있으며 배출수증의 암모니아농도는 폐수의 깊이에 따라 크게 변화하는 것으로 나타났다.

• 한국자동차공학회논문집
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• 제20권1호
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• pp.95-105
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• 2012

The selective catalytic reduction (SCR) system is a highly-effective aftertreatment device for NOx reduction of diesel engines. Generally, the ammonia ($NH_3$) was generated from reaction mechanism of SCR in the SCR system using the liquid urea as the reluctant. Therefore, the precise urea dosing control is a very important key for NOx and $NH_3$ slip reduction in the SCR system. This paper investigated NOx and $NH_3$ emission characteristics of urea-SCR dosing system based on model-based control algorithm in order to reduce NOx. In the map-based control algorithm, target amount of urea solution was determined by mass flow rate of exhaust gas obtained from engine rpm, torque and $O_2$ for feed-back control NOx concentration should be measured by NOx sensor. Moreover, this algorithm can not estimate $NH_3$ absorbed on the catalyst. Hence, the urea injection can be too rich or too lean. In this study, the model-based control algorithm was developed and evaluated on the numerical model describing physical and chemical phenomena in SCR system. One channel thermo-fluid model coupled with finely tuned chemical reaction model was applied to this control algorithm. The vehicle test was carried out by using map-based and model-based control algorithms in the NEDC mode in order to evaluate the performance of the model based control algorithm.

• 한국자동차공학회논문집
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• 제20권1호
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• pp.20-27
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• 2012

The $NH_3$-SCR characteristics of $NO_X$ over a V-based catalyst are experimentally examined over a wide range of operating conditions, i.e., $170-590^{\circ}C$ and $30,000-50,000h^{-1}$, with a simulated diesel exhaust containing $NH_3$, NO, $NO_2$, $O_2$, $H_2O$, and $N_2$. The influences of the space velocity and oxygen concentration on the standard-SCR reaction are analyzed, and it is shown that the low space velocity and high oxygen concentration promote the SCR activity by ammonia. The best $deNO_X$ efficiency is obtained with a $NO_2/NO_X$ ratio of 0.5 because of an enhanced chemical activity induced by the fast-SCR reaction, while at the $NO_2/NO_X$ ratios above 0.5 the $deNO_x$ activity decreases due to the slow-SCR reaction. The oxidation of ammonia begins to take place at about $300^{\circ}C$ and the reaction products, such as $N_2$, NO, $NO_2$, $N_2O$, and $H_2O$, are produced by the undesirable oxidation reactions of ammonia, particularly at high temperatures above $450^{\circ}C$. Also, $NO_2$ decomposes to NO and $O_2$ at temperatures above $240^{\circ}C$. Therefore, $NO_2$ decomposition and ammonia oxidation reactions deteriorate significantly the SCR catalytic activity at high temperatures.

• 한국해양학회지
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• 제26권2호
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• pp.144-154
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• 1991

낙동강 하구독 건설 후 하구역의 환경특성 및 식물플랑크톤의 군집구조에 관하여 19894월부터 12월까지 조사하였다. 하구독 건설 후 장림천의 영향을 직접받는 하구둑 바로 아래지역은 둑 건설전에 비하여 용존산소가 낮아지고 암모니아 및 인산염의 농도 가 증가하였으며 이는 독 건설 후 낙동강의 유입이 일시적으로 차단되어 물의 정체현 상이 일어나고 이곳에 장님천을 통하여 많은 생활하수 및 공장폐수가 유입 되었기 때 문으로 사료된다. 질산염과 규산염 농도는 염분과 높은 역상관 관계를 나타내어 이들 의 주요 공급원은 낙동강 유입으로 판단되었다. 식물플랑크톤의 현존량은 춘계에는 하 구둑 상류지역에서 Asterionella sp.가, 하계에는 하구에서 Skeletomema costatum의 bloom이 있었으며 둑 건설 전에 비하여 녹조류 및 남조류가 증가하였다. 특히 하구둑 상부지역의 높은 엽록소 b의 농도는 이곳의 담수 녹조류에 기인한 것으로 사료되며 중 요종의 상당한 부분이 오염지표종이었다. 하구독 건설 후 환경특성 및 식물플랑크톤 군집의 변화가 일어나고 있는 것으로 사료된다.

• Fisheries and Aquatic Sciences
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• 제26권8호
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• pp.470-481
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• 2023

Algal overgrowth in shrimp culture ponds can affect the quality of the aquatic environment, thereby adversely affecting the shrimp and causing economic losses. The objective of this study was to evaluate the variation in phytoplankton composition in intensive shrimp ponds in Bac Lieu province, Vietnam. Phytoplankton samples were collected in three black tiger shrimp (Penaeus monodon) ponds and three whiteleg shrimp (Litopenaeus vannamei) ponds. The collected data were analyzed using SPSS and canonical correlation analysis softwares. In total, 75 species of phytoplankton were recorded in black tiger shrimp ponds and 64 species in whiteleg shrimp ponds. Diatoms had the highest species diversity with 29-30 species (39%-47%), followed by green algae with 9-19 species (14%-25%); species numbers of other phyla varied from 5-12 (8%-16%). The total number of phytoplankton species throughout the study varied from 34-50 species. Algal density was relatively high and ranged from 497,091-2,229,500 ind./L and 1,301,134-2,237,758 ind./L in black tiger shrimp and whiteleg shrimp ponds, respectively. The diatom density tended to increase during the final stage of the production cycle in black tiger shrimp ponds. Blue-green algae and dinoflagellates also increased in abundance at the end of the cycle, which can affect shrimp growth. Diatoms were significantly positively correlated with pH, salinity, total ammonia nitrogen, and nitrate (NO₃^-) concentrations (p < 0.05). Blue-green algae and dinoflagellates were positively correlated with salinity, phosphate (PO₄^3-), and NO₃^-. Algal species diversity was lower in the whiteleg shrimp ponds than in the black tiger shrimp ponds. Several dominant algal genera were recorded in the shrimp ponds, including Nannochloropsis, Gyrosigma, Chaetoceros, Alexandrium, and Microcystis. The results of this study provide basic data for further investigations, and they contribute to the management of algae in brackish-water shrimp ponds.

• Animal Bioscience
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• 제37권4호
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• pp.655-667
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• 2024

Objective: This study aimed to assess the impact of a hydroethanolic extract of walnut green husks (WGH) on rumen fermentation and the diversity of bacteria, methanogenic archaea, and fungi in sheep fed a high-concentrate diet. Methods: Five healthy small-tailed Han ewes with permanent rumen fistula were selected and housed in individual pens. This study adopted a self-controlled and crossover design with a control period and an experimental period. During the control period, the animals were fed a basal diet (with a ratio of concentrate to roughage of 65:35), while during the treatment period, the animals were fed the basal diet supplemented with 0.5% hydroethanolic extract of WGH. Fermentation parameters, digestive enzyme activities, and microbial diversity in rumen fluid were analyzed. Results: Supplementation of hydroethanolic extract of WGH had no significant effect on feed intake, concentrations of total volatile fatty acids, isovalerate, ammonia nitrogen, and microbial protein (p>0.05). However, the ruminal pH, concentrations of acetate, butyrate and isobutyrate, the ratio of acetate to propionate, protozoa count, and the activities of filter paper cellulase and cellobiase were significantly increased (p<0.05), while concentrations of propionate and valerate were significantly decreased (p<0.05). Moreover, 16S rRNA gene sequencing revealed that the relative abundance of rumen bacteria Christensenellaceae R7 group, Saccharofermentans, and Ruminococcaceae NK4A214 group were significantly increased, while Ruminococcus gauvreauii group, Prevotella 7 were significantly decreased (p<0.05). The relative abundance of the fungus Pseudomonas significantly increased, while Basidiomycota, Fusarium, and Alternaria significantly decreased (p<0.05). However, there was no significant change in the community structure of methanogenic archaea. Conclusion: Supplementation of hydroethanolic extract of WGH to a high-concentrate diet improved the ruminal fermentation, altered the structure of ruminal bacterial and fungal communities, and exhibited beneficial effects in alleviating subacute rumen acidosis of sheep.