• 제목/요약/키워드: three to

검색결과 109,132건 처리시간 0.096초

Plant co-occurrence patterns and soil environments associated with three dominant plants in the Arctic

  • Deokjoo Son
    • Journal of Ecology and Environment
    • /
    • 제47권1호
    • /
    • pp.1-13
    • /
    • 2023
  • Background: The positive effects of Arctic plants on the soil environment and plant-species co-occurrence patterns are known to be particularly important in physically harsh environments. Although three dominant plants (Cassiope tetragona, Dryas octopetala, and Silene acaulis) are abundant in the Arctic ecosystem at Ny-Ålesund, Svalbard, few studies have examined their occurrence patterns with other species and their buffering effect on soil-temperature and soil-moisture fluctuation. To quantify the plant-species co-occurrence patterns and their positive effects on soil environments, I surveyed the vegetation cover, analyzed the soil-chemical properties (total carbon, total nitrogen, pH, and soil organic matter) from 101 open plots, and measured the daily soil-temperature and soil-moisture content under three dominant plant patches and bare soil. Results: The Cassiope tetragona and Dryas octopetala communities increased the soil-temperature stability; however, the three dominant plant communities did not significantly affect the soil-moisture stability. Non-metric multidimensional scaling separated the sampling sites into three groups based on the different vegetation compositions. The three dominant plants occurred randomly with other species; however, the vegetation composition of two positive co-occurring species pairs (Oxyria digyna-Cerastium acrticum and Luzula confusa-Salix polaris) was examined. The plant species richness did not significantly differ in the three plant communities. Conclusions: The three plant communities showed distinctive vegetation compositions; however, the three dominant plants were randomly and widely distributed throughout the study sites. Although the facilitative effects of the three Arctic plants on increases in the soil-moisture fluctuation and richness were not quantified, this research enables a deeper understanding of plant co-occurrence patterns in Arctic ecosystems and thereby contributes to predicting the shift in vegetation composition and coexistence in response to climate warming. This research highlights the need to better understand plant-plant interactions within tundra communities.

삼음삼양(三陰三陽)에 관(關)한 연구(硏究)

  • 윤창열
    • 혜화의학회지
    • /
    • 제4권2호
    • /
    • pp.337-353
    • /
    • 1996
  • The following results are obtained through study on the Three Eum and Three Yang. 1. Up to nowadays, many people confuse the Great Yang, the lesser Eum, the Great Eum, and the lesser Yang of the Sasang with the Great Yang, the lesser Yang, the Sunlight, the Great Eum, the lesser Eum, and the absolute Eum of the Three Eum and Three Yang becuase they are expressed with the same letters. But the former is the second specialization of the Eum and Yang, and the latter is the transformation of the six climate, so they cannot be the same thing, and there is no connection between them. 2. Three Eum and Three Yang is the outer expression of the six climate, which is coldness, heat, dryness, humidity, wind, and the fire, and it is the conception of the formation of objects which possess SI-JUNG-JONG & BON-JUNG-MAL, and it represents one term of the status of transformation in which the life and the Yang Qi are born, grown, united, and completed. 3. The Three Eum and Three Yang is not only applyed to the outer expression of the six climate, but also to the twelve channels which correspond with the twelve viscera, six differentiation of the disease of the cold, various illness, and the form of pulse. 4. The combination of the Three Eum and Three Yang and the twelve channels is divided into the channel of Sahwa and the channel of Jonghwa, and it also has important relationship with the physiology of the viscera. 5. The division of the six channels of disease of the cold suggested by Junggyung originates from the heat theory in Neagyung, but the six channels in the heat theory are of pathological conception, so the six channels of Junggyung includes the disease of the channels and the viscera. 6. The difference of the Pyo, Bon, Jung Qi of the Three Eum and Three Yang makes the syndrom of the disease diverse so it can be used in the diagnosis and the treatment of disease, and further studies are necessary on this part.

  • PDF

Switched Reluctance Motor의 Single Position Sensor 구동에 관한연구 (A Study on Single Position Driving Meethod of Switched Reluctance Motor)

  • 정윤철
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 2000년도 전력전자학술대회 논문집
    • /
    • pp.709-712
    • /
    • 2000
  • In general three position sensors are needed to drive three phases SRM. Single position sensor driving method for three phases Switched Reluctance Motor(SRM) is proposed in this paper. By using single position sensor the cost of SRM is reduced. But position sensor the cost of SRM is reduced. But position detection at the staring is needed for single position sensor driving method. In this paper we propose the active align method to detect the relative position of rotor to three phases and align to the nearest phase. We proved the validity of the method by experiment and compare with other method.

  • PDF

Analysis of a New Parallel Three-Level Zero-Voltage Switching DC Converter

  • Lin, Bor-Ren;Chen, Jeng-Yu
    • Journal of Electrical Engineering and Technology
    • /
    • 제10권1호
    • /
    • pp.128-137
    • /
    • 2015
  • A novel parallel three-level zero voltage switching (ZVS) DC converter is presented for medium voltage applications. The proposed converter includes three sub-circuits connected in parallel with the same power switches to share load current and reduce the current stress of passive components at the output side. Thus, the size of the output chokes is reduced and the switch counts in the proposed converter are less that in the conventional parallel three-level DC/DC converter. Each sub-circuit combines one half-bridge converter and one three-level converter. The transformer secondary windings of these two converters are connected in series in order to reduce the size of output inductor. Due to the three-level circuit topology, the voltage stress of power switches is equal to $V_{in}/2$. Based on the resonant behavior by the output capacitance of power switches and the leakage inductance (or external inductance) at the transition interval, each switch can be turned on under ZVS. Finally, experiments based on a 2 kW prototype are provided to verify the performance of the proposed converter.

스웜시스템을 위한 자기조직화의 3D 확장 (Extension of Self-organization for Swarm Systems to Three Dimensions)

  • 김재현;김동헌
    • 한국지능시스템학회논문지
    • /
    • 제20권4호
    • /
    • pp.489-496
    • /
    • 2010
  • 본 논문은 3D 환경에서의 스웜시스템을 위한 자기조직화 방법을 제시한다. 스웜 시스템의 자기조직화를 위하여 인력과 척력을 이용하는 인공 포텐셜 함수(Artificial Potential Function, 이하 APF)를 사용하였다. 제안된 연구에서는 2D 환경에서 자기조직화를 위해 사용되어왔던 다양한 포텐셜들을 3D 환경에 맞게 확장 설계한다. 지면이나 수면 등의 경계면을 가지는 3D 환경의 특성을 고려하여 지면 포텐셜(Ground Potential)을 제안한다. 지면 포텐셜을 고려하지 않았을 때와 고려할 때의 비교 결과를 통해 지면 포텐셜의 필요성과 효과를 보여준다. 마지막으로, 다양한 시뮬레이션 결과를 통해 3D 환경에서 확장된 인공포텐셜과 그 성질의 효율성을 보여준다.

소매입체구성을 위한 오그림 (Easing Contraction for Three-dimensional construction of Sleeve)

  • Lee, Myung-Hee
    • 복식
    • /
    • 제42권
    • /
    • pp.223-230
    • /
    • 1999
  • Dressmaking which is defined as the process of changing two-dimensional cloth into three-dime-nsional clothes needs a lot of joining parts. Particularly sleeve needs a more curved surface than other joining parts owing to shape of the top of arms. Easing is used to control the fullness along the seam-line to create the fullness curved shape of the sleeves and it plays an important role in increasing three-dimensional constru-ction power. unfortunately sufficient data regarding effective easing conditions to increase three-dimensional construction power of sleeve are not available. Therefore the author tried to investigate the effective easing conditions to increase three-dimensional construction power of sleeve by cap height. Easing construction power of sleeve by cap height. Easing contraction made by different angles on the sleeve cap curve line previous work were examined and the effective easing conditions according to the variation of angles were determined. This study contains the following objectives. Firstly to obtain the easing contraction ratio in sleeve according to the above easing conditions. Secondly to investigate the three-dimensional construction power or sleeve by the factors of easing contraction. Thirdly to determine for each sleeve the effective easing conditions on the basis of the calcuative easing contraction ratio in the sleeve patterns by cap heights.

  • PDF

Effects of Some Amino Acids on Ammonia Secretion and Extracellular Protease Activity by Three Oomycetes in Synthetic Medium with or without Glucose

  • Ali, Esam H.
    • Mycobiology
    • /
    • 제33권1호
    • /
    • pp.23-29
    • /
    • 2005
  • The effects of different concentrations of three amino acids as carbon and or nitrogen sources on mycelial dry weights, changes in pH values of synthetic medium, ammonia secretion and extracellular protease activity by three zoosporic fungi, pathogens of fish and shellfish, were studied. As compared with the control, the addition of isoleucine and aspartic acid as nitrogen sources were generally stimulative for mycelial dry weight production whereas phenylalanine was inhibitory irrespective to the tested fungal species. When amino acids served as carbon and nitrogen sources, the mycelial dry weights of the three fungi were increased (mostly non-significantly) relative to untreated control but weights were decreased as the concentrations of the three amino acids raised. The addition of individual amino acids as carbon and nitrogen sources to the medium significantly increased pH values of the medium comparable to the control. The addition of each of the three amino acids as carbon and nitrogen sources to the medium significantly induced ammonia secretion by the three species of zoosporic fungi. Ammonia secretion in synthetic medium amended with amino acids as nitrogen source raised by the three zoosporic fungi relative to untreated control except in case of Achlya racemosa treated with isoleucine. Extracellular protease activity was almost promoted in case of Achlya proliferoides and Saprolegnia furcata cultures treated with isoleucine and aspartic acid individually in presence of glucose and vice versa in case of phenylalanine. However, extracellular protease activity of A. racemosa decreased compared with the control at various concentrations of isoleucine and both phenylalanine and aspartic acid assumed inconsistent effects. Extracellular protease activity of the three zoosporic fungi in the medium devoid of glucose varied depending upon zoosporic fungal species, the tested amino acid and the applied concentrations. The values of protease activity were approximately less two folds than that obtained in presence of glucose.

3차원 공간 위상 관계 연산자의 설계 (Design of Three Dimensional Spatial Topological Relational Operators)

  • 김상호;강구;류근호
    • 정보처리학회논문지D
    • /
    • 제10D권2호
    • /
    • pp.211-220
    • /
    • 2003
  • 지리정보시스템은 3차원 위상정보를 표현함으로써 사용자에게 정확하고 정교한 서비스를 제공한다. 이 때에 3차원 위상정보연산을 위해 차원변경방식과 서로 이질적인 공간모델을 사용해야 하는데, 이 방식을 사용할 때는 공간 연산이 어려울 뿐 아니라 서로 호환성이 부족한 문제가 발생한다. 따라서 이 논문에서는 이 문제를 해결하기 위하여 2차원 공간 객체 모델을 수용하는 3차원 공간 객체 모델을 제안하였고, 타당성을 보이기 위하여 구현하여, 그 실행을 보였다. 3차원 공간 위상 관계 연산자를 위하여 DE-9IM 방식을 3차원 개념으로 정의한 DE-9IM을 이용해서 설계하였고, 객체지향 개념을 지원하는 컴포넌트 환경에서 3차원 공간 위상 연산자를 구현하였다. 이 논문에서 제안된 3차원 공간 위상 연산자는 타 시스템과의 상호 운용성을 보장하며, 구현된 공간 위상 관계 연산을 이용하여, 3차원 공간 객체에 대한 효율적인 공간 질의를 수행할 수 있다.

사고종류에 따른 삼상 일체화된 자속구속형 SFCL의 사고전류제한특성 분석 (Analysis of Fault Current limiting Characteristics According to Fault Type in Integrated Three-Phase Flux-Lock Type Superconducting Fault Current limiting)

  • 박충렬;임성훈;박형민;조용선;최효상;한병성
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
    • /
    • pp.54-56
    • /
    • 2005
  • In this paper, we investigated the quench characteristics of HTSC elements in the integrated three-phase flux-lock type SFCL according to fault types such as the single-line-to-ground fault, the double-line-to-ground fault, the line-to-line fault and the three-line-to-ground fault. The integrated three-phase flux-lock type SFCL was the upgrade version of the single-phase flux-lock type SFCL. The structure of the integrated three-phase flux-lock type SFCL consisted of three-phase flux-lock reactor wound on an iron core with the ratio of the same turn between coil 1 and coil 2 in each phase. When the SFCL is operated under the normal condition, the flux generated in the iron core is zero because the flux generated between two coils of each single phase is canceled out. Therefore, the SFCL's impedance is zero, and the SFCL has negligible influence on the power system. However, if a fault occurs in any single-phase among three phases, the flux generated in the iron core is not zero any more. The flux makes HTSC elements of all phases quench irrespective of the fault type, which reduces the current of fault phase as well as the current of sound phase. It was observed that the fault current limiting characteristics of the suggested SFCL were dependent on the quench characteristics of HTSC elements in all three phases.

  • PDF

이토 토요의 건축에 나타난 자기완결적 3차원 조직체의 특성에 관한 연구 (A Study on Characteristics of Self-Contained Three-Dimensional Organic Body found in Architecture of Ito Toyo)

  • 김종진
    • 한국실내디자인학회논문집
    • /
    • 제26권2호
    • /
    • pp.55-63
    • /
    • 2017
  • Recent projects of Japanese architect, Ito Toyo have been evolved into innovative and experimental stages that are unique and different from other contemporary architects. Since Ito established his own office in 1971, there were several critical changes and developments in terms of architectural philosophy as well as design methods. Particularly, after Sendai Mediatheque, Ito has tended to focus on creating three-dimensional organic body in which architectural form, space, structure, facilities, images are merged all together. With this new type of three-dimensional structure, Ito aims to generate a new notion of architecture as 'living organism'. This paper tried to analyze Ito's new concept of architecture, design process of three-dimensional organic body and its ultimate characteristics and meanings. For the analysis, three projects were selected: Taichung Metropolitan Opera House(2005), Berkeley Art Museum and Pacific Film Archive(2007), The New Deichman Library in Oslo(2008). These projects clearly represent several types of three-dimensional organic body. After the comparative studies, it is found that, in Ito's design process and method, there are unique characters: ambivalent relationship between plan and three-dimensional form, aiming new/hyper reality through complicated collaboration of analogue and digital design tools, and contradictory relationship with surrounding urban context. Although there are some limitations and restrictions, ever-evolving Ito's design concept and methods are very much valid and meaningful in contemporary spatial design in various perspectives.