• 제목/요약/키워드: Surface Expansion

검색결과 998건 처리시간 0.032초

급속상악확대술 시행 후 지대치와 지지골 표면에 나타나는 치근흡수의 불화나트륨 단독투여를 통한 예방에 대하여 (The effect of NaF on bone and tooth resorption around an anchor tooth during a rapid maxillary expansion procedure)

  • 민승기;정규림
    • 대한치과교정학회지
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    • 제34권6호
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    • pp.526-536
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    • 2004
  • 본 연구는 급속상악확대술 시행 후 보정기간중에 지대치의 압박측 치근흡수에 불화나트륨의 경구 투여가 영향을 미치는지를 알아보기 위하여 시행되었다. 이차성징을 아직 나타내지 않은 10마리 소아기 암캐에 견치를 주지대치로 사용하는 주조형 상악 확대장치를 제작, 장착하였다 상악확대장치는 20일간에 걸쳐 5mm 확장시켰으며, 교합면 방사선사진을 이용하여 정중구개봉합의 이개를 확인하였다. 실험동물은 실험군 5 마리와 대조군 5 마리로 나뉘었으며, 보정기간 중 실험군에는 2.2 mg/kg/day의 불화나트륨 (불소로서 1.0mg/kg/day)을 캅셀제의 형태로 1 일 2 회로 나누어 단독 경구 투여하였다. 실험동물들을 보정 후 0 일, 15 일, 30 일, 45 일, 및 60 일째에 각 군당 한 마리씩 배정하여 충분한 마취로 희생시킨 후 상악골을 절취하였다. 이후 실험동물의 좌측 상악 견치의 압박측 치근표면과 압박측 견치 협면을 덮고 있던 골 조직의 치아측 표면을 주사전자현미경을 이용하여 관찰하였다. 본 실험에서 압박측 치근표면을 관찰한 결과 45일 보정군과 60일 보정군의 대조군에서 흡수소와가 발현되는 빈도가 높았다. 지대치 압박측 치근을 덮는 골면에 나타나는 흡수소와의 발현은 30일의 보정기간 이후부터 실험군에서 적게 나타남을 알 수 있었다. 차후 급속상악확대술을 시행하는 경우 효과적인 NaF의 투여시기와 용량에 대한 검증이 필요하리라 생각된다.

Expansion ratio estimation of expandable foam grout using unit weight

  • WooJin Han;Jong-Sub Lee;Thomas H.-K. Kang;Jongchan Kim
    • Computers and Concrete
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    • 제33권4호
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    • pp.471-479
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    • 2024
  • In urban areas, appropriate backfilling design is necessary to prevent surface subsidence and subsurface cavities after excavation. Expandable foam grout (EFG), a mixture of cement, water, and an admixture, can be used for cavity filling because of its high flowability and volume expansion. EFG volume expansion induces a porous structure that can be quantified by the entrapped air content. This study observed the unit weight variations in the EFG before and after expansion depending on the various admixture-cement and water-cement ratios. Subsequently, the air content before and after expansion and the gravimetric expansion ratios were estimated from the measured unit weights. The air content before expansion linearly increased with an increase in the admixture-cement ratio, resulting in a decrease in the unit weight. The air content after the expansion and the expansion ratio increased nonlinearly, and the curves stabilized at a relatively high admixture-cement ratio. In particular, a reduced water-cement ratio limits the air content generation and expansion ratio, primarily because of the short setting time, even at a high admixture-cement ratio. Based on the results, the relationship between the maximum expansion ratio of EFG and the mixture ingredients (water-cement and admixture-cement ratios) was introduced.

지반침하 거동특성 분석을 위한 암반의 부피팽창률에 관한 연구 II (A Study on the Volumetric Expansion Ratio of Rock Mass for Subsidence Behavior Analysis II)

  • 이승중;정용복;최성웅
    • 터널과지하공간
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    • 제18권6호
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    • pp.436-446
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    • 2008
  • 지반침하 지역의 지표침하량은 지하 채굴적의 높이보다 작은 것으로 분석되고 있다. 이러한 원인은 암반의 부피팽창률이며 아직까지 이에 대한 연구는 미흡한 실정이다. 따라서 본 연구에서는 부피팽창률 산정을 위해 3차원 입체 모델을 이용하여 지표침하량과 침하영향범위를 고려한 이론식을 유도하였다. 또한 수치해석 시 부피 팽창률의 적용성 검토를 위하여 개별요소 프로그램인 UDEC(Universal Distinct Element Code)을 이용하여 측압계수의 변화에 따른 지표침하의 변화 양상과 점착력의 변화에 따른 부피팽창률의 변화 양상을 분석하였다.

증기발생기 관판내부 균열 열화 특성 (Degradation Characteristics of Tubes in the Steam Generator Tubesheet)

  • 조남철;강용석;김형남;이국희
    • 한국압력기기공학회 논문집
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    • 제10권1호
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    • pp.7-14
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    • 2014
  • There has been extensive experience associated with the operation of SGs wherein it was believed, based on NDE, that throughwall tube indications were present within the tubesheet. The installation of the SG tubes usually involves the development of a short interference fit, referred to as the tack expansion, at the bottom of the tubesheet. The tack expansion was usually effected by a hard rolling process and thereafter, in most instance, by the expansion of a urethane plug inserted into the tube end and compressed in the axial direction. The rolling process by its very nature is considered to be intensive with regard to metalworking at the inside surface of the tube and would be expected to lead to higher residual surface stresses. Alternate repair criteria(ARC) in the tack expansion area have been developed and applied to nuclear power plants in USA, however domestic nuclear power plants have not applied ARC for tubes in tubeheet area yet. In consideration of the degradation characteristics of tubes in the Steam Generator tubesheet, this paper suggests ARC application for tubes in the steam generator tubesheet of the domestic nuclear power plants in order to assure life time of the steam generator as well as nuclear power plants.

GIS와 RS를 이용한 도시확산 포텐셜 평가기법의 개발 (Development of a potential evaluation method for urban expansion using GIS and RS technologies)

  • 김대식;정하우
    • 농촌계획
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    • 제10권3호
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    • pp.41-51
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    • 2004
  • This study aims to develop a potential evaluation method for urban spatial expansion using remote sensing (RS) and geographic information system (GIS). A multi-criteria evaluation method with several criteria and their weighting values was introduced to evaluate the score and quantification of the potential surface around the existing cities. The six criteria with one geographic factor, slope, and five accessibility factors, time distance from center of the city, national road, interchange of expressway, a big city, and station, were defined for the potential. RS techniques were applied for classification of the actual urban expansion maps between two periods, and GIS functions were used for score of accessibility criteria with a distance decay function from geographic, road and several point maps, which was developed in this study. The new methodology was applied to a test area, Suwon, between 1986 and 1996. In order to optimize the six weighting values, this study made new findings to search the optimal combination of the weighting values from new methodology, weighted scenario method for intensity order (WSM), combined with intensity order and AHP method, including a trial and error method for sensitivity analysis to make the intensity order. The optimal combination of the weighting values by the new method generated the optimal potential surface, considering spatial trend of urban expansion in the test area.

하복의 체표변화에 따른 동작적합성에 관한 연구 -하복동작 및 체형을 중심으로- (A Study on the Movement-Fitness according to the Surface changing of Lower-Limb -On the Movements and Shapes of Lower-limb-)

  • 박영득;서영숙
    • 한국의류학회지
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    • 제20권2호
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    • pp.257-269
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    • 1996
  • The puropose of this study was to investigate the movement-fitness according to the surface changing of lower limb The experimental items were divided into the lower limb movements (5) and body-shapes (7). This study was done by the expansion and contraction rate consideration of length, girth Also, the lower half of body shape-change on the movements and body-shapes by flat shell was done simultaneously. The summarized findings resulted from experiments and investigation are suggested as follows; First, when commpared the expansion and contraction rate of the length and girth items, the expansion rate of the back crotch length (14~20%), hip girth (10~ 21%) and knee girth (6.2~18.5%) in rabbit leap movement was the most notable among all variables considered in this experimentation. On the others hand, the front croth length (-22~-52%) contracted remarkably. And big-thigh type was the most notable on the body-shape comparision. Second, in comparision of the expansion and contraction rate of the area on the blocks, the expansion of the hip (50~200%) and knee (51~74%) block was the most remarkable. Especially, in the sit on knees movement of the hip-down type expanded 209.4%. Third, in comparision of the lower half of body shape-change, on the movements and body- shapes by the flat shell, under the influence of knee-joint and hip-joint the shape-changs of the hip and knee block was the most notable. But the shape-change of the waist, abdomen, calf, and ankle was feeble.

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의치상 레진의 중합 방법에 따른 크기의 안정성 및 표면 형태에 관한 연구 (DIMENSIONAL STABILITY AND SURFACE MORPHOLOGY OF VARIOUS DENTURE RESINS)

  • 채숙영;방몽숙
    • 대한치과보철학회지
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    • 제30권3호
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    • pp.401-410
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    • 1992
  • The purpose of this study was to investigate the dimensional changes and surface morphology of dentures processed by various polymerization conditions. The measurements were done by taking radiograph and using vernier calipers and each specimen was observed on scanning electron microscope. Results obtained were as follows. 1. The difference of dimensional stability was not recognized between various polymerization conditions(heat-cured resin, pour-type resin, microwave-cured resin, and injection molding resin). 2. There were expansion and shrinkage in the occlusal dimension, shrinkage in the frontal dimension, and expansion in the lateral dimension. 3. Scanning electron microscope pictures of heat-cured resin showed dense and regular surface morphology. 4. Microwave-cured resin surface appeared more regular and smooth than pour-type resin but less dense and more irregular than heat-cured resin. 5. Scanning electron microscope pictures of pour-type resin with the lowest dimensional change showed the most irregular surface morphology.

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진동둘레선 설계를 위한 진동체표변화에 관한 연구 (Body Surface Changes at Armhole Area for the Pattern of Armhole Line)

  • 이정란;임원자
    • 한국의류학회지
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    • 제20권5호
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    • pp.930-942
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    • 1996
  • This study was done to provide the characteristics of body surface changes at armhole area. Experiments were carried out at upper arm and upper body inchuding 67 items, 74 segments by the stanard posture and arm movements. The subjects were 15 females of twenty aged. The major conclusions of this study are; 1. On the circumference items of upper arm, armhole circumference was decreased by all arm movement, especially high contracted on front armhole line. The most contracted segments of armhole circumference were from the shonlder point to front and back interscye breadth point. Axillary circumference was increased 5 cm to the utmost, so the function of sleeve pattern would be decided by axillary circumference. 2. The lengths of upper arm were decreased near center line, sleeve cap length was contracted 3∼4 cm. Posterior armpit point area was increased both length and breadth. According to the rates of expansion and contraction, the diagram of expansion and contraction of upper arm was suggested. 3. On upper body, back side chest breadth was increased exceedingly and shoulder length was decreased most. It was apparent that surface changes of upper body were greatly larger as far away from center front and center back line. The rates of expansion and contraction of upper body were also represented as a diagram of surface changes.

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체형별 상복동작에 따른 상체의 체표면 변화에 관한 연구 -남자대학생을 중심으로- (A Study on the Variation of the Body surface Area by the Arm movements to Somatotype -The Subject of the College Men-)

  • 김진경
    • 대한가정학회지
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    • 제26권2호
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    • pp.1-13
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    • 1988
  • The purpose of this study was to classify somatotype of males, to show changes of the body skin surface by the somatotype. The size of sample was 156 males between age 20 and 24. Somatotype classified into Bending somatotype, Standard somatotype, Turning over somatotype. And according to the somatotype, changing of the upper part of the body by the arm movements analyzed through gypsum experiment. The result obtained from this study were as follows; 1. the variation of the upper part of the body form by changing the am movements, by the increasing of movements, shoulder-point ws moved to be inside or upside, the anterior armpit point & armpit point were moved to the upside. 2. As a result of investigating into the rate of the expansion and contraction of the basic lines and body surface area by the arm movements, the rate of expansion and contraction of the basic lines by the arm movements, the side sea length showed the maximum rate of extension in 135 degrees, the shoulder length showed the maximum rate of contraction in 135 degrees. The rate of expansion and contraction on the body surface area by the arm movements showed the phenomenon of contraction, of items F1, F6, B1, B9 showed the phenomenon of extension, of items F3, F4, F8, F9, B8, B9. 3. According to somatotypes, items which show the significant difference were, of items f3, f8, b3, b8, F2, F7, F8, B3, B7, in all movements.

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영구자석 여자전동기 회전부 축의 열박음에 따른 변형특성 (Distortion Response of Motor Axis with Permanent Magnet as Shrink Fitting)

  • 우병철;정연호;강도현
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 C
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    • pp.1451-1453
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    • 2003
  • Shrink fitting is often used to replace conventional mechanical fasteners and fastening methods. Localized heating of the mating surface provides temporary expansion and allows slip fit assembly. The resulting interference fit exhibits exceptional strength without surface deformation at ambient temperatures. We studied an analysing method to find out a deformation of motor axis with shrink fitting of thermal expansion.

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