• 제목/요약/키워드: DO

검색결과 63,307건 처리시간 0.065초

Automatic Control Of Dissolved Oxygen In Activated Sludge Aeration Tank

  • Park, Kwang-Soo;Heo, Nam-Hyo;Lee, Hae-Goon;Han, Gee-Baek;Kim, Chang-Won
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • 제3권2호
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    • pp.113-119
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    • 1999
  • The quality of the effluent from an activated sludge aeration tank can deteriorate when the substrate removal rate decreases due to an abrupt reduction in the DO concentration, which is affected by such operating conditions as the loading rate, temperature, wastewater composition, and so on. In this research, a DO control system that includes a PI (proportional-integral) controller/Hiraoka controller was developed and applied to a pilot-scale activated sludge process, then its acceptability was estimated. The applicability of the respiration rate to DO control was also estimated. The respiration rate indicated a variety of input organic loading rates, which is the main disturbance to the DO concentration in an aeration tank. When the influent concentration incrementally decreased and increased between CODcr 1,000 mg/l and 100 mg/l, the control system with a PI controller exhibited a good llperformance-the average DO concentrations were 2.00$\pm$0.14 mg/l and 1.88$\pm$0.15 mg/l (set value was 2.0 mg/l), respectively, and the settling time was just 10 minites. When the control system was operated for 4 days, the DO concentration was 1.99$\pm$0.18 mg/l and 32.6% of the air flowrate was saved. However, the fluctuations in the respiration rates and air flowrates were severe, which could be harmful to the stability of the biomass and mechanical stability of the blower. A possible approach to solve this problem may be the simultaneous control of the loading rate and DO concentration.

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1991~1993년 전남지방에서 발생한 렙토스피라증, 쯔쯔가무시병, 신증후출혈열에 관한 연구 - 보건기관에 보고된 자료를 중심으로 - (A Study on Leptospirosis, Tsutsugamushi Disease and Hemorrhagic Fever with Renal Syndrome in Chonnam in 1991~1993 - Based on notified cases to the Public Health Center -)

  • 박형철;이명학;손명호;조귀영;이정희;강미정;김홍;김개환;김순천
    • 농촌의학ㆍ지역보건
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    • 제19권2호
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    • pp.119-128
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    • 1994
  • This study was performed on 302 cases of leptospirosis, tsutsugamushi disease and hemorrhagic fever with renal syndrome(HFRS) which occurred in Chonnam(Do) in 1991 through 1993. The results were as follows : 1. 81.8% of the patients with Leptospirosis and 54.5% of the HFRS patients were men while 61.4% of the patients with tsutsugamushi disease were women. 2. Most patients lived in rural areas(Gun), their educational level was elementary School or lower and their occupations were either farmer or jobless. 3. Peak ages were 40s for leptospirosis(36.4%) and 50s for tsutsugamushi disease and HFRS(32.9% and 36.4% respectively). 4. The high incidence areas of tsutsugamushi disease were northern, eastern and a diagonal line, from northeast to southwest, of the Chonnam area, and these are consistent with a mountainous district. 5. In monthly distribution leptospirosis was higher in Sep. and Oct., and tsutsugamushi disease and HFRS were higher in Oct. and Nov. 6. The first case is occurring and the last case shows up later than in past years.

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충청북도 생태숲 조성예정지의 자원식물상 (The Resource Plants in Construct-Reserved Site of Ecological Forest, Chungcheongbuk-do, Korea)

  • 유주한;조흥원;진연희;윤희빈;이귀용;한주환;이철희
    • 한국자원식물학회지
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    • 제18권3호
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    • pp.390-402
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    • 2005
  • 본 연구는 충청북도 제천시 생태숲 조성예정지의 자원식물상을 체계적으로 파악하기 위해 수행되었다. 이 지역은 북위 $37^{\circ}\;12'$, 동경 $127^{\circ}\;57'$에 위치하고 2004년 3월부터 10월까지 조사하였다. 관속식물상은 83과 238속 324종 44변종 3품종 등 총 371종류가 확인되었고 자원식물상 조사결과 관상용 식물자원은 178종 $(47.98\%)$, 식용 식물자원은 232종$(62.53\%)$, 약용 식물자원은 257종$(69.27\%)$, 기타용 식물자원은 154종$(41.51\%)$로 나타났다. 산림청 희귀 및 멸종위기식물은 너도바람꽃, 백작약, 태백 제비꽃, 미치광이풀로 조사되었다.

Sea Prince호 유류유출 후의 남해안 소리도-금오도 주변 연성퇴적물 대형저서동물의 군집구조 (Community Structure of Soft-bottom Macrozoobenthic Communities near the Sori-Keumo Islands, Southern Coast of Korea after the Sea Prince Oil Spill)

  • 최진우;서진영;임현식;신현출
    • 한국수산과학회지
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    • 제39권spc1호
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    • pp.151-164
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    • 2006
  • We monitored the current macrozoobenthic community structure after the Sea Prince oil spill around Keumo-do and Sori-do, Korea. Macrobenthic animals were collected seasonally around Sori-Keumo do using a van Veen grab ($0.1m^2$) from October 1999 to April 2000. In total, 196 species were identified at 46 sites around Keumho-do. The mean density was 1,460 individuals/$m^2$, and polychaetes comprised 80% of the total density of the macrozoobenthic. Dominant species were the polychaete Tharyx sp. (51%), the echinoderm Amphioplus megapomus (5%) and the polychaete Lumbrineris longifolia (3%). We identified 176 macrobenthic species at 36 sites around Sori-do. The mean density was 1,068 individuals/$m^2$, and polychaetes was the most abundant faunal group, comprising 41%, followed by mollusks (24%) and echinoderms (20%). Dominant species in Sori-do were the mollusk Potamocorbula amurensis (23%), the chinoderm Amphioplus megapomus (14%), and the polychaete Tharyx sp. (10%). The overall community structures in the study area showed few seasonal changes, although there was a gradual change in the species composition within each benthic community. Tharyx sp. was the most abundant species in the study area. Because this species has not been found in the other coastal areas except during recent investigations, it is considered to have increased during the course of community succession after the oil spill. The macrozoobenthic around Keumo-do showed little change in species richness, whereas around Sori-do, it showed a few increases in species richness after the summer of 1998. The overall density showed the same trend as species richness. Based on improved community indices, we suggest that the macrozoobenthic communities around Sori-Keumo Islands are gradually recovering from the oil-spill damagecaused by the oil spill.

강원도 지역 가임기 여성의 분만서비스 접근성 분석 (The Spatial Accessibility of Women in Childbearing Age for Delivery Services in Gangwon-do)

  • 최소영;이광수
    • 보건행정학회지
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    • 제27권3호
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    • pp.229-240
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    • 2017
  • Background: This study purposed to analyze the spatial accessibility of women in childbearing age to the healthcare organizations (HCOs) providing delivery services in Gangwon-do. Methods: Network analysis was applied to assess the spatial accessibility based on the travel time and road travel distance. Travel time and travel distance were measured between the location of HCOs and the centroid of the smallest administrative areas, eup, myeon, and dong in Gangwon-do. Korean Transport Database Center provided road network GIS (Geographic Information System) Database in 2015 and it was used to build the network dataset. Two types of network analysis, service area analysis and origin-destination (OD)-cost matrix analysis, applied to the created network dataset. Service area analysis defined all-accessible areas that are within a specified time, and OD-cost matrix analysis measured the least-cost paths from the HCOs to the centroids. The visualization of the number of the HCOs and the number of women in childbearing age on the Ganwon-do map and network analysis were performed with ArcGIS ver. 10.0 (ESRI, Redlands, CA, USA). Results: Twenty HCOs were providing delivery services in Gangwon-do in 2016. Over 50% of the women in childbearing age were aged more than 35 years. Service area analysis found that 89.56% of Gangwon-do area took less than 60 minutes to reach any types of HCOs. For tertiary hospitals, about 74.37% of Gangwon-do area took more than 60 minutes. Except Wonju-si and Hoengseong-gun, other regions took more than 60 minutes to reach the tertiary hospital. Especially, Goseong-gun, Donghae-si, Samcheok-si, Sokcho-si, Yanggu-gun, Cheorwon-gun, and Taebaek-si took more than 100 minutes to the tertiary hospital. Conclusion: This study provided that the accessibility toward the tertiary hospital was limited and it may cause problems in high-risk delivery patients such as over 35 years. Health policy makers will need to handle the obstetric accessibility issues in Gangwon-do.

경상북도 내 유통 농산물 중의 잔류농약 동향 (2004~2008년) (Tendency of Residual Pesticides in Commercial Agricultural Products in Gyeongsangbuk-Do Area (the year 2004~2008))

  • 양승태;손진창;정광현;이창일;김미정;박희숙;차춘근
    • 한국식품위생안전성학회지
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    • 제24권4호
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    • pp.338-347
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    • 2009
  • The content of residual pesticides in commercial agricultural products in Gyeongsangbuk-Do area was investigated for 5 years extending the year 2004 through 2008. The detection rates of residual pesticides in agricultural products by year were similar in range of 11.6~16.4%. But the violation rates showed lower values in the last years from 4.5% of the year 2004 to 0% of the year 2007. The highest residual concentration of each pesticide detected in commercial agricultural products was investigated by year. That is, in the year 2004 and 2005, chlorpyrifos, chlorothalonil, diazinon, endosulfan, ethoprophos, fenarimol and procymidone were detected over the tolerance in kale, parsley, celery, chard and lettuce, and in the year 2006, permethrin in the soybean and peanut. The detection rate and violation rate of pesticides were highly increased in the order of the endosulfan, chlorpyrifos, procymidone, chlorfenapyr, fenitrothion, imazalil, isoprothiolane, methidathion and permethrin. The detection rate and violation rate of pesticides were increased after August every year.

한국 수달(Lutra lutra)의 분포 현황 (Distribution of Eurasian Otter Lutra lutra in Korea)

  • 조영석;원창만;김주필
    • 환경생물
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    • 제24권1호
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    • pp.89-94
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    • 2006
  • 본 연구는 수달의 배설물에 근거해 한국 수달의 서식지 분포 및 그 패턴을 유추하기 위하여 수행되었다. 본 연구에서 분포 조사에 사용한 총 750개의 조사 격자 (13.75X11\;km) 중 34%에 이르는 255개의 구획에서 수달의 배설물이 존재한다는 것을 확인하였다. 수달 배설물의 지역적 분포 빈도는 경상북도(49.62%), 강원도 (49.56%), 충청북도 (41.67%), 경상남도 (38.00%), 전라북도 (37.93%), 전라남도 (24.24%), 충청남도 (20.29%), 경기도(7.36%)순이었다. 수달의 배설물이 발견된 대부분 지역에서 아주 적은 수(평균 1.7 spraints/sprainting site)의 배설물만을 확인하였으므로 지역별 개체군의 크기는 크지 않은 것으로 추정된다. 수달의 배설물에 근거해 유추한 수달 서식지의 분포 패턴은 한국에 서식하는 수달의 보전 및 관리를 위한 기초 생태자료로써 중요한 기여를 할 것으로 사료된다.

울릉도의 화산층서와 단층에 대한 연구 (A Study on Volcanic Stratigraphy and Fault of Ulleung-do, Korea)

  • 김기범;이기동
    • 지질공학
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    • 제18권3호
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    • pp.321-330
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    • 2008
  • 울릉도 화산체의 지질과 지질구조 및 화산활동상을 연구하기 위해서 선행된 연구 자료를 수집하고 현장조사를 실시하였다. 울릉도는 동해 해저에서부터 약 3,000m 높이의 화산체로 해수면 부근의 기저는 현무암질 집괴암이며 그 상위로 조면암질 집괴암, 조면암, 조면암질 부석과 조면안산암 순으로 분포하고 있다. 나리분지의 칼데라는 함몰에 의해 역삼각형의 단층이 나타나고 있고, 나리분지를 중심으로 북동-남서방향과 북서-남동방향의 단층들이 분포하고 있다. 신생대 제4기(Quaternary)의 울릉도 화산활동은 해수면 부근의 현무암질 집괴암 및 응회암 분출의 제1기, 조면암질 집괴암 및 응회암이 분출한 제2기, 조면암질 용암류의 분출의 제3기, 조면암질 부석이 분출한 제4기, 칼데라 내의 조면암질 안산암이 분출시기인 제5기로 구분하였다. 울릉도의 지질은 다양하고 복잡하여 지질공학 또는 응용지질분야에서 접근하기가 용이하지 않았다. 따라서 이번 연구에서는 울릉도 지질을 단순화하여 이들이 쉽게 활용할 수 있도록 자료를 제공하고자 하였다.

"도문대작(屠門大嚼)"을 통해 본 조선중기 지역별 산출 식품과 향토음식 (A study on Regional foods in the middle of Chosun Dynasty through Domundaejac)

  • 차경희
    • 한국식생활문화학회지
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    • 제18권4호
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    • pp.379-395
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    • 2003
  • Regional foods is influenced by weather, local and social environment etc. The purpose of this study was to understand that regional foods in the middle of Chosun Dynasty through Domundaejac. Some of representative dishes of the Hansung and Kyonggi-do Area is duck(rice cake) of seasonally celebrated days, hangua(korea confectionary) and rice wine. Typical foods in Chungchong-do Area is included persimmon, jujube, watermelon and wax gourd. Some of the well-known food in Kangwon-do Area is pear, bangpungchuk(gruel), sukebyung(rice cake), woongjijunggua(korea confectionary) and sanat-kimchi(picked mustard leaves and stem) that is seemed characteristics of mountainous section. Some of the famous dishes in Cholla-do Area is backsanja(korea confectionary), tea, chuksun kimchi(bamboo shoot pickle), citrus fruits and ear shell. Kyongsan-do Area ia famous persimmon, bamboo fruit, dasik(korea confectionary) and yakban(glutinous rice cake). Hwanghae-do Area is famed pear and choshi as assumed the eatly form of gochujang(thick soypaste mixed with red pepper). Representative dishes are deljjuk(blue berry), herring, sangat-kimchi(picked mustard leaves and sterm) in Hamgyong-do Area and daemandu(big dumpling) in Pyongan-do Area. The coast area is famous for using lots of sea food. Fresh seafood is consumed raw, and clams, fish and seaweed are liberally added to soups and other dishes. The East coast is catched salmon, flatfish, codfish, sandfish and mackerel The West coast is catched yellow corvenia, lobster, tiny shrimp and large-eyed herring. The South coast is catched sea mussel, codfish and laver.

재래종대두의 결실일수군별과 제형질과의 관계 (Relationship between Fruiting Period and Agronomic Characters in Korean Local Soybean Collections)

  • 송희섭;김봉용;권신한
    • 한국작물학회지
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    • 제33권4호
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    • pp.380-385
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    • 1988
  • The present study was conducted to evaluate agronomic characters of the soybean germplasm which was collected from the sites covering whole areas of southern Korean peninsula. A total of 2,748 Korean native soybeans was grouped for fruiting period and in this group frequency distribution of the important agronomic characters and relationships among the characters were determined. The results obtained were summarized as follows; The soybean germplasm was comprised of SeoulㆍKyonggi-do 7.5%, Kangwon-do 13.3%, Chungchongbuk-6.6%. Chungchongnam-do 12.3%, Chollabuk-do 10.7%, Chollanam-do 12.6%, Kyongsangbuk-do 20.8%, Kyongsangnam-do 15.3% and Cheju-do 0.6% in number of collections. Frequency distribution of the germplasm for fruiting period was 0.14% in Group I (below 55 days). 1.67% in Group II (56-60 days), 10.58% in (Group III(61-65 days), 23.18% in Group IV(66-70 days), 25.91% in Group V(71-75 days) 19.79% in Group Ⅵ(76-80 days), 15.1% in Group Ⅶ(81-85 days) and 3.6% in Group Ⅷ(over 85 days). The lines over 70 days in fruiting period were as much as 64.4% of germplasm. The fruiting period varied largely from 45 days to 91 days. Fruiting period was positively correlated to seed weight, days to maturity, days to flowering, plant height and number of branches per plant, respectively. While. it was negatively correlated to number of pods, lodging and virus infectivity, repectively, and in particular negative correlation was shown significantly between yield and fruiting period. Average yield was very high as much a 1.389kg/ha in fruiting period Group I, and decreased with increment of fruiting period, 1.400kg/ha in Group II. 1.384kg/ha in Group III. 1,299kg/ha in Group IV, 1,197kg/ha in Group V, 1,117kg/ha in Group Ⅵ, 967kg/ha in Group Ⅶ and 832kg/ha in Group Ⅷ.

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