• 제목/요약/키워드: stem flow

검색결과 221건 처리시간 0.024초

Measurement and estimation of transpiration from an evergreen broad-leaved forest in japan

  • Hirose, Shigeki;Humagai, Tomo′omi;Kumi, Atsushi;Takeuchi, Shin′ichi;Otsuki, Kyoichi;Ogawa, Shigeru
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2001년도 학술발표회 논문집(I)
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    • pp.52-59
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    • 2001
  • Methods to measure and estimate transpiration of a forest composed of evergreen broad-leaved trees (Pasania edulis Makino) are studied. Heat pulse velocity has been measured along with soil moisture and micrometeorological factors at the Fukuoka Experimental Forest, the Research Institute of Kyushu University Forests in Fukuoka, Japan (33$^{\circ}$38'N, 130$^{\circ}$31'E, alt. 75m). Tree cutting measurement was conducted to convert the heat pulse velocity into sap flow and transpiration. A big leaf model to calculate transpiration and Interception loss is examined and the estimated values are compared with the measured values obtained from the heat pulse measurement. The results show that 1) Pasania edulis Makino posessing radial pore structure had relatively high water content and high heat pulse velocity even within the central part of the stem near the pith, 2) the heat pulse velocity was well correspond to the water uptake in the tree cutting measurement, 3) the estimation of sap flow based on the heat pulse velocity is accurate, and 4) the big leaf model using the parameters obtained from measurement of a portable photosynthesis system in one day in summer gives reasonable estimation of transpiration independent of seasons and weather.

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한국 가족윤리변천사 IV -1950년 6.25동란이후부터 1960년대 말 까지- (A Historical Approach to the Korean Family Ethics -from period of korean war: 1950's to the end of 1960's-)

  • 이정덕;박허식
    • 대한가정학회지
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    • 제37권7호
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    • pp.45-68
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    • 1999
  • From the Korean War in 1950 to the end of the 1960s, the traditional feudal residue which had been prevalent in our society was disrupted and suddenly replaced with modem western order. Family ethics were also to be changed, so that western family ethics replaced those of confucian ones. This is part of a study that examines the flow of family ethics from ancient families to modem families to find out the stem of Korean family ethics. Since there are almost no existing studies that have dealt this topic, newspaper, magazine and also interviews with the people of thus era were very helpful to this study along with the related books and papers. On account of limited space, this study focused in the first place on husband-wife ethics and parent-child ethics among family ethics.

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4 홀 Micro Multi Cell Tube 의 압출공정 해석 및 기계적 특성 평가 (Extrusion process Analysis and Evaluation of Mechanical property for Micro Multi Cell Tube with 4 hole)

  • 이정민;김병민
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2004년도 추계학술대회 논문집
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    • pp.397-400
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    • 2004
  • The direct extrusion with porthole die can produce condenser tube which has the competitive power in costs and qualities compared with the existing conform extrusion. In general, porthole die extrusion has a great advantage in the forming that produces the hollow sections difficult to produce by conventional extrusion with a mandrel on the stem. Especially, condenser tube manufactured by porthole die belongs to sophisticated part and demands tighter dimension tolerance and higher surface finish than any other part. In order to confirm the general of porthole die extrusion, we perform the 3D FE analysis of hot porthole extrusion in non-steady state by using DEFORM 3D and investigate a pattern of elastic deformation for porthole die through the stress analysis using ANSYS 5.5 during extrusion process.

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다발성 후하소뇌동맥 해리성 동맥류 - 증 례 보 고 - (Multiple Dissecting Aneurysms of the PICA Trunk - Case Report -)

  • 김종태;김한규
    • Journal of Korean Neurosurgical Society
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    • 제30권1호
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    • pp.66-72
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    • 2001
  • Apatient with multiple dissecting aneurysms of a posterior inferior cerebellar artery trunk who presented with SAH is reported. A 58-year-old woman presented with sudden occipital headache, dizziness and vomiting. The intial vertebral angiography revealed a suspicious pearl and string sign at the proximal posterior inferior cerebellar artery(PICA) segment. After 2 weeks, follow up angiography showed a progression of the proximal PICA dissection and newly developed dissecting aneurysm of the distal PICA segment. A far lateral suboccipital transcondylar appoach confirmed two dissecting aneurysms at distant sites of the PICA trunk. The dissection segments were wrapped with muslin wrap, which preserved the flow through the PICA and brain stem perforators. The angiographys at 3 weeks and 6 months after operation revealed serial disappearance of the dissecting aneurysms which is distal to proximal. The diagnosis, course and treatment of the dissecting aneurysms of the PICA are discussed with literature review.

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Novel Reproductive Techniques in Swine Production - A Review

  • Okere, C.;Nelson, L.
    • Asian-Australasian Journal of Animal Sciences
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    • 제15권3호
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    • pp.445-452
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    • 2002
  • The main objective of modern reproductive technologies in pig reproduction is to increase reproductive efficiency and rates of genetic improvement. They also offer potential for greatly extending the multiplication and transport of genetic materials and the conservation of unique genetic resources in reasonably available forms for possible future use. The development and refinement of these technologies is concentrating on gamete and embryo collection, sorting and preservation, in vitro production of embryos, culturing, manipulation of embryos (splitting, nuclear transfer, production of chimeras, establishment embryo stem cells, and gene transfer) and embryo transfer. Also, the development of these novel technologies is facilitated by modern equipment for ultrasonography, microscopy, cryopreservation, endoscopy, and flow cytometry, microinjectiors, micromanipulators and centrifugation. The real impact on herd productivity will come from combining new reproductive techniques with powerful DNA technologies. The new reproductive techniques will allow a rapid turnover of generations, whereas the DNA technology can provide selection, which does not need phenotypic information when the selection decisions are made.

HPLC에 의한 가시오가피 및 오가피 중 Hyperin의 정량 (Determination of Hyperin in Acanthopanax senticosus and A. sessiliflorus by HPLC)

  • 이상현;정하숙;신국현;김박광
    • 약학회지
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    • 제48권4호
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    • pp.231-235
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    • 2004
  • A new high performance liquid chromatographic method was applied for the determination of hyperin in Acanthopanax senticosus and A sessiliflorus. The stationary phase used was $\beta$-Bondapak $C_{18}$ reverse-phase column and a mobile phase program was a gradient of acetonitrile and distilled water at a flow rate of 1.0 ml/min. Hyperin was detected at 210 nm, and the analysis was successfully carried out within 20 min. Hyperin was detected in the one year-grown and two years-grown stem of A senticosus (0.47 and 0.13 mg/g, respectively) and A sessiliflorus (0.14 and 0.03 mg/g, respectively). Hyperin was detected in the main and branch root of A sessiliflorus (0.30 and 0.09 mg/g, respectively). But there is no detection of hyperin in the main and branch root of A senticosus.

Preparation, Characterization, and Catalytic Applications of Graphene-palladium Nanocomposites

  • 홍영국;유세희;박준범
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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    • pp.262-262
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    • 2012
  • Modifications of graphenes have been studied for catalytic applications due to their advantages such as high surface area, conductivity and thermal stability. In this research, individual graphene oxide (GO) sheets were exfoliated from graphite using Hummers and Offeman method. Pd nano-particles were deposited on the GO surface using Pd2+ ion exchange where hydroxyl groups on the GO act as nucleation sites of Pd nanoparticles and their dispersions. The thermal treatments of the Pd-GO in H2 flow produced Pd-Graphene nanocomposites. Their catalytic performances in Sonogashira reaction were investigated. Morphological and chemical structures of the GO, Pd-GO, and Pd-Graphene were investigated using FT-IR, XRD, TEM, STEM, and XPS. The catalytic performances have been investigated using microwave reactor.

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Nanostructured Polymer Electrolytes for Li-Batteries and Fuel Cells

  • 박문정
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2012년도 춘계학술발표대회
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    • pp.71.2-71.2
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    • 2012
  • There are rising demands for developing more efficient energy materials to stem the depletion of fossil fuels, which have prompted significant research efforts on proton exchange fuel cells (PEFCs) and lithium ion batteries (LIBs). To date, both PEFCs and LIBs are being widely developed to power small electronics, however, their utilization to medium-large sized electric power resources such as vehicle and stationary energy storage systems still appears distant. These technologies increasingly rely upon polymer electrolyte membranes (PEMs) that transport ions from the anode to the cathode to balance the flow of electrons in an external circuit, and therefore play a central role in determining the efficiency of the devices; as ion transport is a kinetic bottleneck compared to electrical conductivity, enormous efforts have been devoted to improving the transport properties of PEMs. In present study, we carried out an in-depth analysis of the morphology effects on transport properties of PEMs. How parameters such as self-assembled nanostructures, domain sizes, and domain orientations affect conductivities of PEMs will be presented.

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트랜섬 선미를 가지는 선형의 포텐셜 유동해석 (Potential How Analysis for a Hull with the Transom Stern)

  • 최희종;전호환
    • 한국해양공학회지
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    • 제15권1호
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    • pp.1-6
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    • 2001
  • This study focuses on the potential flow analysis for a hull with the transom stern. The method is based on a low order panel method. The Kelvin type free-surface boundary condition which is known to better fit experimental data for a high speed is applied. To treat a dry transom stern effect a special treatment for the free-surface boundary condition is adopted at the free-surface region after the transom stern. Trim and sinkage, which are important in high speed ships, are considered by an iterative method. Pressure and momentum approaches are used to calculate the wave resistance. Numerical calculations are performed for Athena hull and these results are compared with the experimental data and also other computational results.

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Hematopoiesis Activity of Sambucus javanica on Chloramphenicol-induced Aplastic Anemia Mouse Model

  • Putra, Wira Eka;Rifa'i, Muhaimin
    • Natural Product Sciences
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    • 제25권1호
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    • pp.59-63
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    • 2019
  • Hematopoiesis has a pivotal role in the maintenance of body homeostasis. Ironically, several hematological disorder caused by chemicals, drugs, and other environmental factors lead to severe bone marrow failure. Current treatments like stem cell transplantation and immunosuppression remain ineffective to ameliorate this diseases. Therefore, a newtreatment to overcome this entity is necessary, one of them by promoting the usage of medicinal plants. Thus, this study aimed to evaluate the hematopoiesis potency of S. javanica berries and leaves extracts in chloramphenicol (CMP)-induced aplastic anemia mice model. In this present study, several types of blood progenitor cell such as $TER-119^+VLA-4^+$ erythrocytes lineage, $Gr-1^+$ granulocytes, and $B220^+$ B-cell progenitor cells were evaluated by flow cytometry analysis. Accordingly, we revealed that S. javanica berries and leaves extracts significantly promoted $TER-119^+VLA-4^+$ erythrocytes lineage and $Gr-1^+$ granulocytes after exposed by CMP. Thus, these results suggested that S. javanica berries and leaves extracts might have hematopoiesis activity in CMP-induced aplastic anemia mice model.