• Title/Summary/Keyword: ROOT

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The Effects of Root Gap on Mechanical Properties and Fatigue Strength of Weldment (용접부의 기계적 성질 및 피로강도에 미치는 루트 간격의 영향)

  • 이원근;장경복;강성수
    • Journal of Welding and Joining
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    • v.19 no.2
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    • pp.98-103
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    • 2001
  • Root gap out of standard by welding deformation is frequently produced at butt weld joints of steel bridge. For example although standard root gap is below 6mm at butt weld joints of plates under 15mm thickness. maximum 35mm root opening is produced at the weld field. At this case, the part out of standard is generally built up and the rest part is welded by WPS. Direct welding without built-up welding is preferred in weld field because built-up welding process bring about the cost-up at manufacturing. To apply this direct weld to root gap out of standard, the investigation about mechanical properties and fatigue at weldment is required. Inthisstudy, therefore the verification for direct weld without built up is performed at weldment as root gap. It includes tension, bending. hardness, impact and fatigue test for each welding specimen of 6mm, 25mm, 35mm root gap.

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The Regulation of Root Hair-specific Expansin Genes

  • Cho, Hyung-Taeg
    • The Plant Pathology Journal
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    • v.20 no.1
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    • pp.18-21
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    • 2004
  • The root hair provides a major entering spot for the symbiotic legume rhizobia. It is obvious that dynamic cell wall modification occurs in the plant root hair during the early microbe invasion. Expansins are nondestructive cell wall-modifying proteins that are involved in cell growth and differentiation. Among about 40 expansin genes in Arabidopsis, two expansin genes are expressed specifically in the root hair cell. Orthologous genes of this Arabidopsis root hair expansins have been found in other Brassica members, rice, and Medicago truncatula (a legume). In this review, I discuss the probable function of expansins during the early symbiotic process between the root hair and microbes and the regulation of root hair expansin genes in a comparative approach.

Effect of Different Soil pH on the Root Growth of Temperate Grass Species (토양산도의 차이가 주요화본과목초의 뿌리생육에 미치는 영향)

  • 이혁호;박근제;이종열
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.7 no.1
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    • pp.1-7
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    • 1987
  • A pot experiment conducted to investigate the root elongation and weight of grasses, i.e. Orchardgrass, tall fescue and perennial ryegrass under the conditions adjusted pH of half vertical part of pot soil to seven levels from 2 to 8. 1. Root growth was drastically decreased as soil pH was lowed. 2. Higer the soil pH, longer the root length. Increase of soil pH to 6 increased the root length of orchardgrass, perennial ryegrass and tall fescue. 3. Regardless of grass species, most of roots distributed to the soil which adjusted pH from 6 to 7. 4. Dry weight of root was increased to pH 7 of soil in orchardgrass and perennial ryegrass and was 55 to 78% of production of pH 6 compared with soil pH 7. In case of tall fescue, dry root weight in the soil pH 7 was 69.8% of root weight growed in soil pH 6.

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Wood pelletizing using pine root waste biomass - different pelletizing properties between trunk and root biomass of Pinus densiflora (소나무 뿌리 폐기물을 이용한 목질 펠릿 제조 - 목부와 뿌리로 제조한 펠릿의 특성 비교)

  • Shin, Soo-Jeong;Han, Gyu-Seong;Myeong, Soo-Jeong;Cho, Jung-Sik;Yeon, Ik-Jun
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.10a
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    • pp.71-73
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    • 2008
  • Different biosolid fuel (wood pellet) properties between trunk and root of pine (Pinus densiflora) biomass were investigated. Trunk has more organic solvent extracts and Klason lignin content which has higher heating values than root biomass component. In root biomass, polysaccharides content was higher than trunk biomass. Based on Higher Heating Value (HHD) analysis and ash content, trunk biomass showed better solid fuel characteristics than root biomass. But pine root biomass had lower HHD than trunk biomass, its HHD values were higher than other hardwood or annual plant lignocellulosic biomass.

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A STUDY ON THE ROOT CANAL MORPHOLOGY OF HUMAN MAXILLARY SECOND PREMOLAR WITH TRANSPARENT SPECIMENS (투명표본(透明標本)에 의한 상악(上顎) 제이소구치(第二小臼齒)의 근관형태(根管形態)에 관(關)한 연구(硏究))

  • Lee, Chung-Sik
    • Restorative Dentistry and Endodontics
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    • v.8 no.1
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    • pp.139-145
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    • 1982
  • Eighty four human maxillary second premolars were injected with china. ink, decalcified, cleared and used in study, in vitro, to determine the number of root canals, the frequency and location of lateral canals, the frequency and location of transverse ansatomoses, the curvature of root canals, the location of apical foramens, and the frequency of apical deltas. The results were as follows: 1. Most of the teeth demonstrated one canals, but the only tooth was found to have two canal. 2. Of the 101 canals studied, 85.1% of the canals were found to have lateral canals and these ramifications were usually located in the apical third of the root. 3. Of the two root canals in one root, 25.4% of the canals were found to have transverse anastomoses and were usually located in the middle third of the root 4. 33.3% of apical foramens were located directly on the root apex and 66.7% of them laterally, and 46.5% of canals showed distal curvature.

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Investigation of Phenolic, Flavonoid, and Vitamin Contents in Different Parts of Korean Ginseng (Panax ginseng C.A. Meyer)

  • Kim, Ji-Sang
    • Preventive Nutrition and Food Science
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    • v.21 no.3
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    • pp.263-270
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    • 2016
  • This study investigated the phenolic, flavonoid, and vitamin constituents in the main root, root hair, and leaf of ginseng. The total individual phenolic and flavonoid contents were the highest in the leaf, followed by the main root and root hair. Ferulic acid and m-coumaric acid were found to be the major phenolics in the main root and root hair, while p-coumaric acid and m-coumaric acid were the major phenolics in the leaf. Catechin was the major flavonoid component in the main root and root hair, while catechin and kaempferol were the major flavonoid components in the leaf. Pantothenic acid was detected in the highest quantity in the non-leaf parts of ginseng, followed by thiamine and cobalamin. Linolenic acid and menadione were the major components in all parts of ginseng.

Effect of Pot Depth on Root Development and Distribution during Seedling Growing Period in Tobacco. (육묘포트 깊이가 담배의 뿌리발달 및 분포에 미치는 영향)

  • 이상각;심상인;강병화;이학수;석영선
    • Journal of the Korean Society of Tobacco Science
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    • v.19 no.1
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    • pp.18-23
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    • 1997
  • The study was carried out to clarify reasonable production of healthy seedling, optimal Pot depth, and appropriate transplanting time, which can be deduced from understanding of seedling quality. Seedling quality results from growth of root and shoot, morphology and distribution of root system under influence of Pot depth during seedling growing period. Stem height, shoot dry weight, leaf area and leaf number were increased in proportion to depth of pots. Growth of shoot and root during seedling growing period showed the most dramatic development between 20th and 25th day after temporary planting. Root number increased as pot depth decrease and total root length and dry weight increased as pot depth increase. In 5cm pot, relative multiplication rate was higher and mean extension rate was lower than other depth of Pot. The limitation of pot volume in which rhizosphere was located enhance the development of roots of second and third order. At 20th days after temporary Planting root distribution was relatively uniform in length and development of adventitious root on stem base was poor as Pot depth decreased.

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Effect of Light Intensity and Temperature on the Growth and Root Yield of Panax ginseng (광도와 온도가 인삼의 생육 및 수량에 미치는 영향)

  • 이종화
    • Journal of Ginseng Research
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    • v.12 no.1
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    • pp.40-46
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    • 1988
  • This study was conducted to investigate the optimum temperature and light intensity of photosynthesis and transmittance in the shade for better growth and root yield of ginseng. The 3-year-old ginseng plants grown under the shade of 5, 10 and 20% transmittance did not show any significant difference in the stem length, stem diameter, leaf area and root length. The root diameter markedly increased under the shade of 10% and 20% transmittance, and the root was the heaviest under the shade of 20% transmittance. The 6-year-old ginseng plants grown at 20% transmittance showed the largest root diameter but the root length was not influenced by transmittance. The root was heaviest in the shade of 20% transmittance.

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A STUDY ON THE ROOT CANAL MORPHOLOGY OF HUMAN MAXILLARY FIRST PREMOLAR WITH TRANSPARENT SPECIMENS (투명표본(透明標本)에 의한 상악(上顎) 제일소구치(第一小臼齒)의 근관형태(根管形笞)에 관(關)한 연구(硏究))

  • Han, Young-Chul
    • Restorative Dentistry and Endodontics
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    • v.7 no.1
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    • pp.139-144
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    • 1981
  • Eighty four human maxillary first premolars were injected with china ink, decalcified, cleared and used in study, in vitro, to determine the number of root canals, the frequency and location of lateral canals, the frequency and location of transverse anastomoses, the curvature of root canals, the location of apical foramens, and the frequency of apical deltas. The results were as follows: 1. Most of the teeth demonstrated two canals, but 20.2% of the teeth were found to have one canal. 2. Of the 151 canals studied, 38.4% of the canals were found to have lateral canals and these ramifications were usually located in the apical third of the root. 3. Of the two root canals in one root, 35.7% of the canals were found to have transverse anastomoses and were usually located in the middle third of the root. 4. 15.2% of apical foramens were located directly on the root apex and 84.8% of them laterally, and 52.3% of canals showed distal curvature.

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Comparison of Growth Characteristics of 1- and 2-year-old Bare Root and Container Seedling of Chamaecyparis obtusa (편백 1, 2년생 노지묘와 용기묘의 생장특성 비교)

  • Song, Ki Sun;Cha, Young Geun;Choi, Jin Young;Kim, Jong Jin
    • Journal of Korean Society of Forest Science
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    • v.101 no.2
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    • pp.317-323
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    • 2012
  • This study was performed in order to explore the growth characteristics by growing stage in the containerized seedling and the bare root seedling of Chamaecyparis obtusa Sieb. et Zucc., which is the major plantation species of Korean southland. The height growth of 1-year-old bare root seedlings was better than containerized seedlings, which grew in the containers with capacity of 31.2 mL and 300 mL. The root collar diameter growth was the best in the containerized seedlings of container with 300 mL. The 2-year-old bare root seedlings were surveyed to be better in the height and root collar diameter growth than the containerized seedlings of container with 300 mL. In the comparison of dry mass production, it was the highest in 32 mL containerized seedlings as for 1-year-old above ground and in 300 mL containerized seedlings as for below-ground and total dry mass production. In case of 2-year-old seedlings, it was indicated to be high in bare root seedling as for the part above ground and in dry mass production of the containerized seedling as for the part below ground. In the comparison on root morphological traits of seedlings such as the total root length, the root project area, the root surface area, the average diameter in root, and the root volume, all of 1 and 2-year -old containerized seedlings showed the higher growth than the bare root seedlings except the average diameter in root. Synthesizing the results of this experiment, the containerized seedlings are relatively excellent in root development compared to bare root seedlings in the process of producing seedlings of C. obtusa, thereby being judged to have grown into excellent seedlings.