Feeding Behavior of One-year-old Silver Carp, Hypophthalmichthys molitrix, on Dominant Phytoplankton During a Summer in the Enclosure of Shallow-hypertrophic Lake

최민규,김백호,Choi, Min-Kyu,Takamura, Noriko,Kim, Baik-Ho 한국하천호수학회 2000 생태와 환경 Vol.33 No.4

수심이 얕은 부영양호수에서 우점하는 식물플랑크톤에 대한 1년생 백련어의 섭식특성을 조사하고자, 1997년 5월 23일부터 9월 18일까지 호수의 연안에 4개의 enclosure를 설치하고, 어류투입 이후의 각 enclosure수중과 어류의 장 내용물 중의 식물플랑크톤 군집의 변화를 비교하였다. 조사기간동안 각 enclosure의 수온, 플랑크톤의 총생물량, 어류 아가미의 여과공 등은 시간에 따라 른 변화가 없었으며, 어류성장은 주로 투입된 어류의 밀도에 의존되었다. 어류의 내용물에 의하면, 저밀도 투입 enclosure에서 수중과 어류 전장간의 플랑크톤군집의 유사도가 높게 나타났으며(p<0.05), 전체적으로 모든 enclosure에서 크기가 큰(>$100,000{\mu}m^3$) 식물플랑크톤-Oscillatoria, Anabaena, Melosira등은 어류투입이후 크게 감소되지 않았다. 어류의 먹이선택지수(${\alpha}$)와 플랑크톤의 크기 (Ingestion unit)사이에도 매우 낮은 상관성을 보였다(r = 0.001, p>0.5). 식물플랑크톤의 분석결과, 백연은 남조나 녹조에 비해 규조를 더 선호하였는데, 이는 규조의 세포벽이 다른 조류에 비해 소화과정동안 쉽게 파괴되지 않고, 저배율의 현미경적시야에서도 간단히 확인된다는 점 등,선택지수를 과대평가하게 되는 단점이 있기 때문에 백련어의 먹이습성에 대한 방법론적 개선이 필요하다고 판단된다. The feeding behavior of 1-year-old silver carp, Hypophthalmichthys molitrix (Val.) on phytoplankton species in a shallow hypertrophic lake was studied from 22 May to 18 September, 1997. Over the experimental period, the filter-pore sizes of the fish, the total biomass of the phytoplankton and the water temperature in each enclosure changed little with time. The fish biomass in each enclosure increased with time, while their percentage of weight gain correlated negatively to the stocking density, due perhaps to competition for prey. An analysis of gut contents of silver carp showed a strong similarity between the algal communities in the foregut and the water, and was significant for the fish enclosure with a low density (p<0.05). The presence of silver carp rarely suppressed the abundance of phytoplankton such as Oscillatoria, Anabaena and Melosira even at high ingestion levels. There were weak relationships between the IU values of each phytoplankton and the selectivity of fish on them (r = 0.001, p>0.5). There was no doubt that the silver carp fed unselectively when cyanobacteria populations were high, even though the selectivity index for diatoms was slightly higher than those for cyanobacteria, green algae and cryptomonads. Improvements in methodologies are needed to clearly understand and generalize the feeding behavior of silver carp.

의회 인클로저와 근대성 : 길과 생활공간의 직선화

이영석(Lee Young-Suk) 부산경남사학회 2010 역사와 경계 Vol.74 No.-

The parliamentary enclosure in the late eighteenth and early nineteenth centuries is very important especially in the point that it was one of the first examples which showed us the rapid change of the ecological environment by some artificial efforts of the ruling class. Up to now, most of studies on the parliamentary enclosure have been related to the growth of productivity, the decrease of agricultural population or the transition of agricultural labours to industrial workers after enclosures. While traditional historians emphasized the changes influenced by enclosure, revisionists did not agree with them. In this paper I would like to emphasize the fact that the life-spatial changes by the enclosure were based upon the standards of modernity or rationality. Those changes meant the adjustment of scattered strips and furlongs to the planed square-fields, and the establishment of curvilineal roads and fences to linear ones. The linearity of living space would be related to the growth of rationality, and it was the expression of modernity at that times. But we can not know how it influenced peasants' attitude because they did not leave their own records. After the enclosure, most of small peasants and cottagers continued to live in their villages on the basis of works and jobs succeeded from the enclosure such as fencing, the opening of new road or the re-making of new villages. In addition to it, they could work by the day for jobs of other villages experiencing the enclosure. But their work was only temporary. After the rapid fall of grain prices in 1815, many villages of the Midlands experienced the deep change. Most of peasants left for urban or industrial districts for their living.

A simple formula for insertion loss prediction of large acoustical enclosures using statistical energy analysis method

Kim, Hyun-Sil,Kim, Jae-Seung,Lee, Seong-Hyun,Seo, Yun-Ho The Society of Naval Architects of Korea 2014 International Journal of Naval Architecture and Oc Vol.6 No.4

Insertion loss prediction of large acoustical enclosures using Statistical Energy Analysis (SEA) method is presented. The SEA model consists of three elements: sound field inside the enclosure, vibration energy of the enclosure panel, and sound field outside the enclosure. It is assumed that the space surrounding the enclosure is sufficiently large so that there is no energy flow from the outside to the wall panel or to air cavity inside the enclosure. The comparison of the predicted insertion loss to the measured data for typical large acoustical enclosures shows good agreements. It is found that if the critical frequency of the wall panel falls above the frequency region of interest, insertion loss is dominated by the sound transmission loss of the wall panel and averaged sound absorption coefficient inside the enclosure. However, if the critical frequency of the wall panel falls into the frequency region of interest, acoustic power from the sound radiation by the wall panel must be added to the acoustic power from transmission through the panel.

급격한 조석 감소에 의한 새만금 갯벌 대형저서동물 변화

구본주,신상호,이석 한국해양과학기술원 2008 Ocean and Polar Research Vol.30 No.4

Tidal ranges of inner Saemangeum were largely reduced after the final dyke enclosure, resulting in the former tidal flats becoming either permanently exposed, still influenced by changing tide, or permanently submerged. The effect of reduced tidal range on survival and population stability of tidal flat macrofauna were investigated at three shifted habitats after the dyke completion. At the exposed area, several species survived for 80 days after the dyke enclosure. However, within 120 days, all macrofauna died off due to the elevated temperature during summer. At the intertidal area, some species were maintained until 170 days after the dyke enclosure with a large decrease of the faunal abundance. Species of the submerged area were seen to be more tolerant of the changed environments. The opportunistic species, such as Sinocorophium sinensis, Theora fragilis and Pseudopolydora Kempi, were massively introduced into the submerged area after the dyke enclosure, in which the benthic ecosystem was severely disturbed. Tidal ranges of inner Saemangeum were largely reduced after the final dyke enclosure, resulting in the former tidal flats becoming either permanently exposed, still influenced by changing tide, or permanently submerged. The effect of reduced tidal range on survival and population stability of tidal flat macrofauna were investigated at three shifted habitats after the dyke completion. At the exposed area, several species survived for 80 days after the dyke enclosure. However, within 120 days, all macrofauna died off due to the elevated temperature during summer. At the intertidal area, some species were maintained until 170 days after the dyke enclosure with a large decrease of the faunal abundance. Species of the submerged area were seen to be more tolerant of the changed environments. The opportunistic species, such as Sinocorophium sinensis, Theora fragilis and Pseudopolydora Kempi, were massively introduced into the submerged area after the dyke enclosure, in which the benthic ecosystem was severely disturbed.

Natural convection in a square enclosure with a circular cylinder according to the bottom wall temperature variation

김민성,두정훈,박용갑,윤현식,하만영 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.12

This paper presents the results of immersed boundary method–based two-dimension numerical simulations of natural convection in asquare enclosure with an inner circular cylinder at a Prandtl number of 0.7. This simulation spans three decades of Rayleigh number from103 to 106. This study focuses on the effect of the bottom wall temperature variation of the enclosure on thermal and flow structures ofnatural convection in the enclosure. The distribution of streamlines and isotherms in the enclosure depend strongly on the Rayleigh numberand the bottom wall temperature. When the Rayleigh number becomes larger, the variation in the distribution of streamlines and isothermsin the enclosure according to the bottom wall temperature becomes larger, resulting in the large variation in the number, size, andformation of the convection cells in the enclosure. The distribution of local and averaged Nusselt numbers on the cylinder surface and thetop and bottom walls of the enclosure depending on the Rayleigh number and the bottom wall temperature is presented in this paper.

淸의 北京 遷都와 만주의 北京 移住

박민수 명청사학회 2019 명청사연구 Vol.0 No.51

Even before “Entering the Pass,” the Manchus enforced a strict segregation policy separating the Manchus and Hans. This policy continued even after the Manchus moved their capital to Beijing. Dorgon inherited the Ming Beijing city structure – divided into an inner city and outer city – and utilized this pre-existing structure to separate the Manchus and Hans. Even though the Qing court introduced some policies to compensate the economic losses of the Han civilians who were forced to move, there was no denying that the migration of the bannermen and stabilizing their life took higher priority. One of the most visible but misunderstood policies that signified the segregation of the Manchus and Hans was the Manchu enclosure policy (quandi 圈地). The newly established banner-land around Beijing served two purposes; first is being the spoils of war that the Qing distributed as rewards to the banenrmen; second is being the economic base for the newly settled bannermen. As a result of this enclosure policy, the Han civilians were pushed away from the capital, while the location of the newly immigrated bannermen was concentrated near Beijing. The policy of enclosure reached its height in the fourth year of the Shunzhi era (1647), indicating the movement of the bannermen to Beijing gradually increased over time, but also more or less was concluded by this time. After this, the Qing court officially prohibited any further acts of enclosure, but the prohibition alone did not totally eliminate the practice of enclosure. In practice, civilian lands continued to be subject to enclosure. The enclosed lands were the economic basis for the bannermen, and therefore the practice continued. As we have seen, the enclosure policy was an inevitable policy that the Manchus needed to settle and secure their rule over the new territory; it served as the economic basis that enabled the continuous conquest of the Manchus; it was a realization of the policy of the Manchus and Hans segregation.

The Noise Reduction Effect by the Enclosure of Gas Turbines

박대훈(Dae Hun Park),신유인(Yoo In Shin),박성규(Sung Gyu Park),김강일(Kang Il Kim),송철기(Chul Ki Song) Korean Society for Precision Engineering 2017 한국정밀공학회지 Vol.34 No.4

A gas turbine is the main equipment used in a combined heat and power plant. It generates a high sound pressure noise level. To reduce the noise level, an enclosure is installed around the turbine. The sound insulation performance of the enclosure affects the amount of external noise reduction. In this study, a sound transmission loss analysis is performed using the boundary element method to predict sound insulation performance according to the numbers and shapes of the supporter. Radiated noise analysis is also performed for the main external points of the enclosure using ray-acoustics. The results of these analyses are presented and a design plan is proposed that reduces the sound pressure noise level of the enclosure.

Role of Silica in Phytoplankton Succession : An Enclosure Experiment in the Downstream Nakdong River (Mulgum)

Ha, Kyong,Joo, Gea-Jae The Ecological Society of Korea 2000 Journal of Ecology and Environment Vol.23 No.4

To understand the mechanism of phytoplankton succession in the Nakdong River, the resource availability (silica) and grazing effect on the phytoplankton community were investigated in an enclosure experiment at Mulgum in March 1995. In all enclosures, Stephanodiscus hantzchii was dominant during the first week. Two weeks later, the diatom community in the A (river water only) and B (filtered river water) enclosures was shifted to colonial green algae (Actinastrum sp., Pediastrum spp. and Scenedesmus spp.) and nanoplankton (2~3 ${\mu}$m of diameter) due to the silica depletion. In the C (silica addition in river water, 3 mg 1$^{-1}$ week$^{-1}$) and D (silica addition in filtered water) enclosures, Fragilaria crotonensis and Synedra acus increased as the silica addition was continued. The percentage of small phytoplankton (size, 10~13 ${\mu}$m) in the filtered enclosures (B and D) was much higher than that of A and C enclosures. A laboratory bottle experiment conducted in the fall of 1994 also showed similar results. Therefore, it is concluded that silica and zooplankton are important regulators in phytoplankton succession during the diatom blooming season in the Nakdong River.

지표 미량기체 방출에 대한 두 가지 다른 형태의 Enclosure 기반 측정 방법의 응용 및 Flow-through Dynamic System을 이용한 토양 NO 방출의 민감도 분석

김득수 ( Deug Soo Kim ) 한국농림기상학회 2007 한국농림기상학회지 Vol.9 No.3

지난 수 세기 동안 온실기체와 기타 화학적으로 중요한 미량기체들이 급격하게 증가하였다. 이러한 주요기체가 기후 변화에 미치는 영향을 이해하기 위해서는 각 기체들의 흡원과 발원을 규명하고, 생물권과 대기권 사이에서 발생하는 생물 기원 기체 플럭스들을 특성화하며, 주요 기체를 조절하는 프로세스들을 이해해야 한다. 본 논문에서는 야외 실험을 위한 실용적 방법인 enclosure 기반의 관측법을 소개한다. 특히, 토양표면에서 방출되는 일산화질소 플럭스에 대한 enclosure 내에서의 질량수지 방정식과 flow-through dynamic 플럭스 챔버 기법의 민감도를 제시하고 flow-through dynamic 플럭스 챔버 방법의 물리적인 시스템과 이론을 소개한다. 또한 챔버 벽에서 발생하는 일산화질소의 손실을 고려하므로써 새로운 플럭스 계산식을 소개하였고 그 계산식의 불확실성을 논의하였다. Rapid increases in the concentrations of greenhouse gases and many other chemically important trace gases have occurred over the last several centuries. For understanding the roles of these important gases in global change, it is essential to identify their sources and sinks, to characterize biogenic gas fluxes between the biosphere and atmosphere, and to understand the processes that control them. In this paper, enclosure-based measurements are described in a practical manner for field experiments. Theoretical reviews of mass balance equation in the enclosure and sensitivity of the flow-through dynamic flux chamber technique are presented; specifically for the case of NO flux measurements from soil surface. The physical system and theory behind the flow-through dynamic flux chamber method are examined. New calculation flux formula was introduced by considering NO chemical loss on chamber wall and uncertainties of the NO flux calculation were discussed.

A simple formula for insertion loss prediction of large acoustical enclosures using statistical energy analysis method

김현실,김재승,이성현,서윤호 대한조선학회 2014 International Journal of Naval Architecture and Oc Vol.6 No.4

Insertion loss prediction of large acoustical enclosures using Statistical Energy Analysis (SEA) method ispresented. The SEA model consists of three elements: sound field inside the enclosure, vibration energy of the enclosurepanel, and sound field outside the enclosure. It is assumed that the space surrounding the enclosure is sufficiently largeso that there is no energy flow from the outside to the wall panel or to air cavity inside the enclosure. The comparison ofthe predicted insertion loss to the measured data for typical large acoustical enclosures shows good agreements. It isfound that if the critical frequency of the wall panel falls above the frequency region of interest, insertion loss isdominated by the sound transmission loss of the wall panel and averaged sound absorption coefficient inside theenclosure. However, if the critical frequency of the wall panel falls into the frequency region of interest, acoustic powerfrom the sound radiation by the wall panel must be added to the acoustic power from transmission through the panel.