• Title, Summary, Keyword: Elongation

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Origin of the Vascular Combium in the Developing Hypocotyl of Glycine max Seedling (대두 유식물의 배축에 있어서 유관속형성층의 기원)

  • 강경덕
    • Journal of Plant Biology
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    • v.31 no.4
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    • pp.289-298
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    • 1988
  • The pattern of elongation in the developing hypocotyl of Glycine max shows that the elongation generally proceeds from base to the cotyledonary node in acropetal diredtion, although earlier elongation takes place through the entire hypocotyl. Because the differentiation of the vascular cambium in the hypocotyl advances also acropetally, it can be seen that the acropetal wave of hypocotyl elongation is associated with the acropetal differentiation of the cambium in the hypocotyl elongation is associated with the acropetal differentiation of the cambium in the hypocotyl elongation is associated with the acropetal differentiation of the cambium in the hypocotyl. The elongation of procambial cells occurs not only during active elongation but also after cessation of elongation of the hypocotyl. In tangential view, the procambium of the hypocotyl in early stage has homogeneous structure composed of short cells. Subsequently, these procambial cells elongate actively and then become elongated long cells. These long cells eventually become fusiform initials, while some of elongated long cells are transversely divided and then converted into ray initials. The characteristics of the vascular cambium are entirely acquired some time after hypocotyl elongation is completed, and the transitin from procambium to vascular cambium in the hypocotyl is a rather gradual process.

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Effects of Seed-Soaked $GA_3$ and Inorganic Salts on Mesocotyl and Coleoptile Elongation in Rice

  • Nam, Taeg-Su;Lee, Byun-Woo
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.45 no.1
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    • pp.50-54
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    • 2000
  • The elongation of mesocotyl and coleoptile plays important roles in the seedling emergence and stand establishment of dry direct-seeded rice. Experiments were carried out to elucidate the effects of seed-presoaking treatments of GA$_3$ and some inorganic salts on the mesocotyl, and coleoptile elongation of rice. Seed-soaked GA$_3$ promoted the elongation of mesocotyl, but little effect on the coleoptile elongation. The stimulation effects of GA$_3$ were found to be enhanced by addition of CaCl$_2$ However, the sole treatment of CaCl$_2$ showed no stimulating effect on the mesocotyl and coleoptile elongation. Mesocotyl elongation was most prominent in the combined treatments of 50ppm GA$_3$ with 100 mM CaCl$_2$. The synergistic effects of GA$_3$ and CaCl$_2$ on mesocotyl elongation varied with varietal groups. The stimulating effects of GA$_3$ were enhanced significantly by the addition of CaCl$_2$ in japonica varieties, Dongjinbyeo, Ilpumbyeo and Milyang 95, and tall indica variety, Labelle, but not in semidwarf Tongil type varieties, Tongilbyeo, Milyang 23, and Nampungbyeo, and semi-dwarf indica, Short Labelle. The promoting effects of GA$_3$ on the mesocotyl elongation were decreased in proportion to the lowered osmotic potential by PEG 6000 on the contrary to CaCl$_2$ This implies that the synergistic effects of CaCl$_2$ with GA$_3$ on mesocotyl elongation was not caused by osmotic potential lowered by CaCl$_2$ addition but by the salt itself. Salts such as Ca(NO$_3$)$_2$, MgCl$_2$ BaCl$_2$, NaCl, KCl and KNO$_3$ showed the synergistic effects with GA$_3$ on mesocotyl elongation as well. The degree of synergistic effects showed no differences among salts tested, implying that there is no specificity of ions constituting the salts.

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The Study on Elongation and Torque Measurement in Large Bolt by using Ultrasonic Technology (초음파를 이용한 대형볼트 신장량 및 체결력 측정연구)

  • Ahn, Y.S.;Gil, D.S.;Park, S.G.
    • Journal of the Korea Society For Power System Engineering
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    • v.13 no.3
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    • pp.40-46
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    • 2009
  • This study on the bolt elongation and torque measuring method by ultrasonic nod-destructive method. In the past, The dial gage was used for the elongation measurement of gas turbine bolts. The purpose of this study is to improve the traditional bolt elongation measurement method. The old method using dial gage measures the elongation of the gas turbine bolt. If the length differences among the loading bolts are within the required range, The loading torques of bolts consider as acceptable. But this method can not give the information about torque differences among the loading bolts. It could bring out vibration of turbine due to loading torque differences among the bolts. So the elongation and torque must be measured simultaneously. The new technology using ultrasonic non-destructive method can give the information about bolt elongation and torque. The ultrasonic method basically measures the speed in the bolt material for the calculation the bolt elongation. But the ultrasonic speed varies according to temperature and loading torque of bolts. So the factors of temperature and loading power were investigated and reflected to the calculation of bolt elongation and torque. The results of this study shows the big difference among the bolts torque in the old method and the torque differences among the bolts can be adjusted by reflecting the result of this study. And this torque adjusting method can decrease gas turbine vibration problem due to torque difference among the bolts. So this paper shows ultrasonic method is better than old method for the measurement of bolt elongation and torque.

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Elongation of Contact Length on the Line of Action in Roll Forming of Gears

  • Seizo Uematsu;Lyu, Sung-Ki
    • Journal of Mechanical Science and Technology
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    • v.17 no.3
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    • pp.321-328
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    • 2003
  • The elongation of contact length on the line of action is considered with particular reference for roll forming of gears, and for dynamic behavior of the tooth in meshing. However there is no paper that discuss the elongation of contact length in the load meshing of gears. Based on our investigation, the contact length on the line of action elongates more than the kinematically calculated value. In rolling, as the tool approaches the workpiece, the center distance of the gears decreases by a small amount. But, the elongation of contact length is sensitive. Therefore, the contact point on the line of action is difficult to be determined, which complicates the tooth analysis. In this study, the exact relation between the elongation of contact length and the tooth space over the recess or before the approach are revealed by experiments and kinematic theory. This analytical result applies not only for rolling, but also for the single flank meshing which is done under constant center distance.

Electrical Breakdown Properties of Highly Elongated Polyethylene (고연신(高延伸)Polyethylene의 절연파괴특성(絶緣破壞特性))

  • Park, Dae-Hee;Kim, Dong-Wook;Kang, Sung-Hwa;Lim, Kee-Joe
    • Proceedings of the KIEE Conference
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    • pp.1209-1211
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    • 1993
  • In this paper, the relationship between electrical breakdown properties and the molecular orientation owing to elongation was investigation from electrical conductivity, electrical breakdown strength and X-ray diffraction wag investigated. The changes of the stretching direction, from an a-axis orientation(at high elongation) to a c-axis orientation(at high elongation), as the elongation increases, were determined from X-ray diffraction patterns. These results suggest that the tendency for a decrease in the trap density at a higher elongation is consistent with a continuous change of the reorientation from the a-axis to the c-axis as the elongation increases.

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Effects of Superstructure on Electronic Properties of Polyethylene (Polyethylene의 전자물성(電子物性)에 미치는 고차구조(高次構造)의 효과(效果))

  • Park, Dae-Hee;Kim, Dong-Wook;Kang, Sung-Hwa;Lee, Kee-Joe
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.55-58
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    • 1993
  • In this paper, the relationship between trap properties and the molecular orientation owing to elongation was investigation from TSC, electrical conductivity and X-ray diffraction was investgated. The changes of the stretching direction, from an a-axis orientation(at low elongation) to a c-axis orientation(at high elongation), as the elongation increases. were determined from X-my diffraction patterns. These results suggest that the tendency for a decrease in the trap density at a higher elongation is consistent with a continuous change of the reorientation from the a-axis to the c-axis as the elongation increases.

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The Properties of Electrical Conduction and Photoconduction in Polyphenylene Sulfide(PPS) by Uniaxial Elongation (일축연신에 따른 Polyphenylene sulfide(PPS)의 전기전도 및 광전도 특성)

  • 이운용;장동욱;강성화;임기조;류부형
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.223-226
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    • 1998
  • In this paper, we have investigated how morphology and electrical properties in Polyphenylene sulfide(PPS) are changed by uniaxial elongation. XRD pattern shows that interplanar distance and crystallinities are decreased by increasing elongation ratio. Electrical conduction mechanism of PPS is explained as schottky emission from analysis of electrical current. The electrical current is decreased by increasing elongation ratio. The conductivity is changed remarkably above the glass transition temperature around $(82^{\circ}C)$. The band gap of PPS is evaluated as 3.9-4(eV) from the results of photoconductivity. Increarnent of elongation ratio gives us some information about deep trap formation from photocurrent.

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Effects of IAA on the Elongation and Cell Wall Glycosidase Activities in Excised Rape (Brassica napus L. cv. Yongdang) Hypocotyl Segments (유채 하배축 분절의 신장과 세포벽 분해효소의 활성에 미치는 IAA의 효과)

  • Jun, Sung-Soo
    • Journal of Plant Biology
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    • v.27 no.2
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    • pp.43-50
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    • 1984
  • Effects of IAA on the elongation and cell wall hlysocidase activities were investigated in excised rape (Brassica napus L. cv. Yongdang) hypocotyl segments. IAA promoted the elongation of rape hypocotyl segments. In rape hypocotyls, the first 10-mm segments from the hook exhibited maximal elongation and the capacity of elongation was gradually decreased with increasing distance of each 10-mm from the hook. A good correlation has been obtained between the magnitude of endogenous growth and the activities of $\alpha$, $\beta$-glucosidase and $\alpha$, $\beta$-galactosidase. However, exogenous application of IAA did not seem to enhance the tissue with IAA resulted in acidification of the incubation medium. From these data, we can conclude that IAA seems to enhance elongation of the tissue segments, at least in part, by releasing hydrogen ion into cell wall, some of which may participate in the cell wall extension process, but does not seem to trigger the activation of $\alpha$, $\beta$-glucosidase and $\alpha$, $\beta$-galactosidase.

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Study on the Effects of Single Fiber Tensile Properties on Bundle Tensile Properties through Estimation of HVI Bundle Modulus and Toughness

  • Koo, Hyun-Jin;Jeong, Sung Hoon;Suh, Moon W.
    • Fibers and Polymers
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    • v.2 no.1
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    • pp.144-147
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    • 2001
  • The HVI properites and Mantis single fiber tensile properties were analyzed to evaluate the relationship between fiber and bundle tensile properties. For this study, a new method has been developed for estimating the modulus and toughness of cotton fiber bundles directly from the HVI tenacity-elongation curves. The single fiber tensile properties were shown to be translated well into the bundle tensile properties. The single fiber breaking elongation was found to be the most significant contributing factor to bundle tensile properties. The bundle breaking elongation and toughness were shown to increase as the single fiber breaking elongation increased. The bundle modulus increased as the single fiber breaking elongation and/or standard deviation of single fiber breaking elongation decreased.

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Effect of Deformation Temperature, Strain Rate and Grain Size on the Tensile Properties of 304L Stainless Steel (304L stainless Steel의 인장성질에 대한 변형온도, 변형속도 및 결정입도의 영향)

  • Kang, C.Y.;Sung, J.H.
    • Journal of the Korean Society for Heat Treatment
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    • v.3 no.2
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    • pp.20-31
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    • 1990
  • This investigation has been carried out to make clear the effect of deformation temperature, strain rate and grain size on the tensile properties of 304L stainless steel. Tensile properties of the metastable austenitic 304L steel remarkably influenced by deformation temperature. Tensile strength increased with decreasing deformation temperature and the elongation showed maximum value near $40^{\circ}C$. In order to obtain the high elongation, a large amount of deformation is available in austenite before martensitic transformation and the martensite has to be induced gradually. Tensile strength and elongation increased with decreasing grain size. The temperature representing the maximum elongation shifted to low temperature and the peak width of elongation became broaden with decreasing austenite grain size. The volume fraction of strain induced martensite decreased with decreasing austenite grain size. As the strain rate increase, the temperature representing the maximum elongation value shifted to high temperature and volume fraction of strain induced martensite decreased.

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