• Title, Summary, Keyword: mass propagation

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Root Induction and Propagation of Sedum takesimense Nakai Using Leaf Cutting Method

  • Cheong, Eun Ju
    • Journal of Forest and Environmental Science
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    • v.34 no.1
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    • pp.50-52
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    • 2018
  • The effect of basal nutrients concentrations and exogenous auxin for root induction from leaves of Sedum takesimense were investigated for mass-propagation. Root induction rates were significantly different from the concentrations of basal salts but not influenced by supplemented IBA in the medium. The lowest concentration of MS basal salts (1/10) was most effective to induce roots from leaves followed 1/5 MS, and 1/2 and full strength MS medium. Supplement of IBA $10{\mu}M$ in the medium did not improve the root induction that resulted no differences compare to the hormone free media. Rooted leaves were transplanted in soil and survived in greenhouse.

Numerical Analysis for Wave Propagation and Sediment Transport with Coastal Vegetation (연안식생에 의한 표사이동 특성에 관한 수치해석)

  • Lee, Seong-Dae
    • Journal of Ocean Engineering and Technology
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    • v.21 no.5
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    • pp.18-24
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    • 2007
  • The environmental value of coastal vegetation has been widely recognized. Coastal vegetation such as reed forests and seaweed performs several useful functions, including maintaining water quality, supporting fish (and, thus, fisheries), protecting beaches and land from wave attack, stabilizing sea beds and providing scenic value. However, studies on the physical and numerical process of wave propagation, sediment transport and bathymetric change are few and far between compared to those on the hydrodynamic roles of coastal vegetation. In general, vegetation flourishing along the coastal areas attenuates the incident waves through momentum exchange between stagnated water mass in the vegetated area and rapid mass in the un-vegetated area. This study develops a numerical model for describing the wave attenuation and sediment transport in a wave channel in a vegetation area. By comparing these results, the effects of vegetation properties, wave properties and model parameters are clarified.

Compressive Fracture Behaviors of Transversely Isotropic Jointed Rock Model with an Opening (공동을 포함하는 횡등방성 절리암반 모델의 압축 파괴거동)

  • SaGong, Myung;Kim, Se-Chul;Yoo, Jea-Ho;Park, Du-Hee;Lee, J.S.
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.58-63
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    • 2009
  • Biaxial compression test was conducted on a transversely isotropic synthetic jointed rock model for the understanding of the fracture behaviors of a sedimentary or metamorphic rocks with well developed bedding or foliation in uni-direction. The joint angles employed for the model are 30, 45, and 60 degrees to the horizontal, and the synthetic rock mass was made of early strength cement. From the biaxial compression test, initiation propagation of tensile cracks at norm to the joint angle was found. The propagated tensile cracks eventually developed rock blocks, which was dislodged from the rock mass. Furthermore, the propagation process of the tensile cracks varies with joint angle: lower joint angle model shows more stable and progressive tensile crack propagation. The experiment results were validated from the simulation by using discrete element method PFC 2D. From the simulation, as has been observed from the test, a rock mass with lower joint angle produces wider damage region and rock block by tensile cracks. In addition, a rock model with lower joint angle shows a progressive tensile cracks generation around the opening from the investigation of the interacted tensile cracks.

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Preliminary numerical study on long-wavelength wave propagation in a jointed rock mass

  • Chong, Song-Hun;Kim, Ji-Won;Cho, Gye-Chun;Song, Ki-Il
    • Geomechanics and Engineering
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    • v.21 no.3
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    • pp.227-236
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    • 2020
  • Non-destructive exploration using elastic waves has been widely used to characterize rock mass properties. Wave propagation in jointed rock masses is significantly governed by the characteristics and orientation of discontinuities. The relationship between spatial heterogeneity (i.e., joint spacing) and wavelength for elastic waves propagating through jointed rock masses have been investigated previously. Discontinuous rock masses can be considered as an equivalent continuum material when the wavelength of the propagating elastic wave exceeds the spatial heterogeneity. However, it is unclear how stress-dependent long-wavelength elastic waves propagate through a repetitive rock-joint system with multiple joints. A preliminary numerical simulation was performed in in this study to investigate long-wavelength elastic wave propagation in regularly jointed rock masses using the three-dimensional distinct element code program. First, experimental studies using the quasi-static resonant column (QSRC) testing device are performed on regularly jointed disc column specimens for three different materials (acetal, aluminum, and gneiss). The P- and S-wave velocities of the specimens are obtained under various normal stress levels. The normal and shear joint stiffness are calculated from the experimental results using an equivalent continuum model and used as input parameters for numerical analysis. The spatial and temporal sizes are carefully selected to guarantee a stable numerical simulation. Based on the calibrated jointed rock model, the numerical and experimental results are compared.

Adventitious Bud Formation and Mass Propagation by Root and Propagation Medium of Wild Polygonatum odoratum Druce (야생 둥굴레의 뿌리와 배양토에 따른 대량번식과 부정아 발생)

  • 신동영;박종산;정연권;김학진;권병선;현규환
    • Korean Journal of Plant Resources
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    • v.15 no.1
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    • pp.8-17
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    • 2002
  • To improve new propagation method, I try to propagate wild polygonatum odoratum roots which formate adventitious bud without bud. The obtained results of size of roots and adventitious bud to formate for multiple propagation of wild polygonatum odoratum as the follow. One year grown wild polygonatum odoratum root in 5cm diameter formate 66.5% adventitious buds. One year grown wild polygonatum odoratum root in 15cm in diameter germinate 113% adventitious bud. Two years grown root in 15cm diameter formate adventitious bud three times more then one year root. Wild polygonatum odoratum in 15cm diameter without any bud in experiment plot makes 4 times of propagation. Sand and Perlite media propagaton plot was increased 3.1∼3.3times more than common culture medium. The best result of mass propagation wild polygonatum odoratum is 10mm diameter root and 5cm cut in length to plant sand media plot.

PROPAGATION OF CME IN MULTI-SATELLITE OBSERVATIONS (다중 위성 관측을 이용한 CME 전파 과정에 대한 연구)

  • 성숙경;이동훈
    • Journal of Astronomy and Space Sciences
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    • v.15 no.2
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    • pp.307-320
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    • 1998
  • We investigate the propagation of Coronal Mass Ejections(CMEs) near the earth with multi-satellite observations. Among the CMEs observed in the near-earth between Nov. 1994 and Nov. 1997, we select two events of Jan. 6-11,1997 and Nov. 4-7, 1997 which were observed by more than 3 satellites when these satellites were located apart with a sufficient distance from each other. We determine the speed and propagation of the two CMEs by calculating the position of each satellite in various coordinates and the onset time of each event. The results show that the speed of CMEs becomes significantly reduced when the perturbation arrives in the magnetosphere. It is also suggested that the propagation of the CMEs is approximated as the -x direction in GSE coordinates in the near-earth space.

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A Study on the Landscape Characteristics and Propagation Methods of Korean native Lindera obtusiloba Blume (자생 생강나무의 조경적 특성 및 번식방법에 관한 연구)

  • 심경구;하유미;김영해;심걸보
    • Journal of the Korean Institute of Landscape Architecture
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    • v.27 no.4
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    • pp.50-58
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    • 1999
  • This study was carried out to investigate the growth characteristics and propagation methods of L. obtusiloba as a woody landscape plant. The results are obtained as follows: L. obtusiloba was dioecious shrub and shaped with bush type. Leaves were ovate, obtuse, cordate, 7.05 cm long, 7.20 cm wide, and petiole 2.0 cm long. Flowers of L. obtusiloba were diclinous. Soil acidity ranged from pH 4.06 to 5.53 with the lowest at the Mt. Soo-Ri. Mt. Soo-Ri located near factory district, which was considered to damaged by environmental deteoration. While soil organic matter was highest at Mt. Soo-Ri, inorganic nutrients were low. L. obtusiloba grows in the area with low soil acidity and low content of inorganic. Therefore it seemed to be tolerant to air pollution. L. Obtusiloba was high seed germination rate in the plug box and its shoots were longer than seeding box and softwood cutting of L. obtusiloba showed the rooting rate of 50% at 5,000ppm on June 23. To develop a mass propagation method of Korean native L. obtusiloba through an axillary bud culture as a woody landscape plant, about 2∼3 cm shoots induced from explant were subcultured to new media contained different growth regulators. Shoots multiplied most effectively on a WPM containing 1.0 mg/l BA, producing 5.5 shoots with a shoot length of 2.5 cm per shoot explant.

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Incremental extended finite element method for thermal cracking of mass concrete at early ages

  • Zhu, Zhenyang;Zhang, Guoxin;Liu, Yi;Wang, Zhenhong
    • Structural Engineering and Mechanics
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    • v.69 no.1
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    • pp.33-42
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    • 2019
  • Thermal cracks are cracks that commonly form at early ages in mass concrete. During the concrete pouring process, the elastic modulus changes continuously. This requires the time domain to be divided into several steps in order to solve for the temperature, stress, and displacement of the concrete. Numerical simulations of thermal crack propagation in concrete are more difficult at early ages. To solve this problem, this study divides crack propagation in concrete at early ages into two cases: the case in which cracks do not propagate but the elastic modulus of the concrete changes and the case in which cracks propagate at a certain time. This paper provides computational models for these two cases by integrating the characteristics of the extended finite element algorithm, compiles the corresponding computational programs, and verifies the accuracy of the proposed model using numerical comparisons. The model presented in this paper has the advantages of high computational accuracy and stable results in resolving thermal cracking and its propagation in concrete at early ages.

A Contact Algorithm in the Low Velocity Impact Simulation with SPH

  • Min, Oak-Key;Lee, Jeong-Min;Kim, Kuk-Won;Lee, Sung-Soo
    • Journal of Mechanical Science and Technology
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    • v.14 no.7
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    • pp.705-714
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    • 2000
  • The formulation of Smoothed Particle Hydrodynamics (SPH) and a shortcoming of traditional SPH in contact simulation are presented. A contact algorithm is proposed to treat contact phenomenon between two objects. We describe the boundary of the objects with non-mass artificial particles and set vectors normal to the contact surface. Contact criterion using non-mass particles is established in this study. In order to verify the contact algorithm, an algorithm is implemented in to an in-house program; elastic wave propagation is an analysed under low velocity axial impact of two rods. The results show that the contact algorithm eliminates the undesirable phenomena at the contact surface; numerical result with the contact algorithm is compared with theoretical one.

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Effect of Medium Composition and Growth Regulators on Mass Propagation of Virus-Free Plant from the Meristem Cultures of 'Jarang' Grape ('자랑' 포도 생장점 배양으로부터 무병주 식물 대량번식에 미치는 배지 구성물질과 생장 조절제의 영향)

  • Lee, Jae Wung;Lee, Yun Sang;Hong, Eui Yon;Lee, Seok Ho;Kim, Hong Sik;Kim, Hag Hyun
    • Korean Journal of Plant Resources
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    • v.26 no.2
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    • pp.303-309
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    • 2013
  • This study was performed to clarify the effect of medium compositions and plant growth regulators on the shoot, root formation and growth of 'Jarang' grape for mass propagation of virus-free plant. The formation and growth of shoot were considerably favorable in half-concentration of MS medium. However, the formation of adventitious root per explants (avg. 2.1) was effective in higher concentration (two times) of MS medium. For sucrose concentration, 1% for the shoot formation, 3% for the adventitious root formation and 1% for the growth were observed as yield significant results. With the addition of 0.05% of activated carbon, the shoot growth was improved, and it was effective for the adventitious root formation and growth as well. A pH of 6.8 in the medium was the most suitable for mass propagation; the results showed significant enhancement in the number of nodes and the length of the shoot, 3.9 and 1.3 cm, respectively. The shoot growth was the most vigorous in BA 1.0 mg/L due to the impact of the growth regulator on the mass propagation in it. Consequently, 16.9 shoots per explant were formed in NAA 1.0 mg/L so good results were obtained.