• Title/Summary/Keyword: side of angle

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평행류 열교환기 내부의 열유동 해석 (Heat and Flow Analysis Inside a Parallel-Flow Heat Exchanger)

  • 오석진;정길완;이관수
    • 대한기계학회논문집B
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    • 제27권6호
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    • pp.781-788
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    • 2003
  • In the present study, the heat and flow characteristics of a parallel-flow heat exchanger are numerically analyzed by using three-dimensional turbulent modeling. Heat transfer rate and pressure drop are evaluated using the concept of the efficiency index by varying the locations, the shapes and angles of inlet/outlet, and the protrusion height of flat tube. It is found that negative angle of the inlet improves the heat transfer rate and pressure drop. Results show that the locations of the inlet and outlet should be toward the right side and the left side to the reference model, respectively, in order to enhance the heat transfer rate and pressure drop. Increasing the height of the lower header causes pressure drop to decrease and yields the good flow characteristics. The lower protrusion height of flat tube shows the improvement of the heat transfer rate and pressure drop. The heat transfer rate is greatly affected by the parameters of outlet side such as the location and angle of the outlet. However, the pressure drop is influenced by the parameters of inlet side such as the location and angle of inlet and the height of the header.

바이오 임피던스 분석을 이용한 뇌졸중 편마비환자의 상지 분석 (Analysis on Upper Extremity of Hemiplegic Stroke Patients Using Bioelectrical Impedance)

  • 유찬욱;박주형
    • 한국콘텐츠학회논문지
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    • 제17권10호
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    • pp.94-101
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    • 2017
  • 본 연구는 뇌졸중 편마비 환자 24명을 대상으로 마비측과 비마비측의 바이오 임피던스 값을 비교 분석하고자 하는 것이다. 본 연구에서는 2015년 10월부터 11월 까지 뇌졸중으로 진단 받은 편마비환자 24명을 대상으로 하였다. MultiScan 5000을 이용하여 바이오임피던스를 측정하였고 프래딕션마커(Prediction mark), 저항성분(resistance), 리액턴스(reactance), 위상각(phase angle)을 비교분석하였다. 뇌졸중 편마비 환자와 바이오임피던스 값의 비교분석을 위해 뇌졸중 편마비 가 아닌 일반인 6명의 오른쪽과 왼쪽을 비교분석하였다. 뇌졸중 편마비 환자의 마비측과 비마비측 부위에서 임피던스 값을 측정하여 정량화된 수치로 나타낸 결과 뇌졸중 편마비 환자의 마비측과 비마비측의 프래딕션마커(Prediction mark), 리액턴스(reactance), 위상각(phase angle)의 값의 유의한 차이를 보였다(p<0.05). 일반인을 대상으로 오른쪽과 왼쪽의 프래딕션마커(Prediction mark), 리액턴스(reactance), 위상각(phase angle)의 값의 유의한 차이를 보이지 않았다(p>0.05). 본 연구 결과를 통해 뇌졸중 편마비 환자의 마비측과 비마비측의 임피던스값의 유의한 차이가 있다는 것을 알 수 있었고 또한, 이를 통해 임상의 재활치료를 받는 뇌졸중 환자의 치료에 정량화된 수치로 측정할 수 있는 유용한 평가도구로서의 가능성을 제시하였다. 향후 연구에서는 임피던스 분석을 이용하여 뇌졸중환자의 마비측과 비마비측의 분석뿐만 아니라 다양한 대상군, 다양한 신체부위 그리고 재활치료 중재의 효과 등을 측정하는 연구가 필요할 것으로 보인다.

Evaluation of Articular Eminence Morphology in Patients with Spontaneous Temporomandibular Joint Dislocation Using Cone Beam Computed Tomography

  • Kim, Ji Hoo;Park, Hyun-Jeong;Seo, Yo-Seob;Ryu, Ji-Won;Ahn, Jong-Mo
    • Journal of Oral Medicine and Pain
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    • 제47권1호
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    • pp.27-37
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    • 2022
  • Purpose: This study aimed to broaden our understanding of the predisposing factor and treatment of dislocation by analyzing and evaluating the morphology of the articular eminence (AE) in subjects with temporomandibular joint (TMJ) dislocation using cone beam computed tomography (CBCT). Methods: The subjects were divided into two groups: dislocation (31 subjects) and control (32 subjects). CBCT was used to examine 126 TMJs in 63 subjects (26 males, 37 females). The height, width, and posterior slope of the AE were measured in the parasagittal plane. The posterior slope was measured using the "top-roof line angle (TR angle)" method and the "best-fit line angle (BF angle)" method. The AE on the left side (AEL) and the AE on the right side (AER) of the subjects in the dislocation group were separately analyzed and compared with the control group after taking measurements. The average value of both sides was used when comparing with subjects with bilateral dislocation. Results: Dislocations were more frequent in females (67.7%) than in males (32.3%). The dislocation group showed a gentler TR angle than the control group in the AER and in the average of AE on the both sides (AEB). The same group also showed a wider AE in the AEL and the AER (p<0.05). In subjects with unilateral dislocation, the width of the AE with dislocation was narrower and the TR angle and BF angle was steeper than the other side without dislocation (p<0.05). Conclusions: In subjects with unilateral TMJ dislocation, the posterior slope of the AE is steeper, and the width is narrower at the site of dislocation compared to the site without dislocation. However, in subjects with bilateral TMJ dislocation, AEB were wider, and the mean value of the posterior slope of AEB was gentler than that of the control group.

Micro Reverse-pyramid Array를 이용한 일체형 Sheetless LCD Backlight의 광학적 특성 (Optical Characteristics of Sheetless LCD Backlight Using Micro Reverse-pyramid Array)

  • 전화준;임교성;곽진석;권진혁
    • 한국광학회지
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    • 제23권3호
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    • pp.119-123
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    • 2012
  • LCD backlight unit (BLU)에서 도광판 상부에 micro reverse-pyramid array (MRPA) 또는 micro reverse-cone array (MRCA)을 설치함으로써 기존의 확산 시트와 프리즘 시트를 없애고 구조를 단순화하였으며, 광학적 시뮬레이션을 통하여 새로운 도광판의 최적 조건을 얻었다. MRPA와 MRCA의 측면각과 높이, 윗변의 반지름이나 윗변의 길이에 따라 휘도와 시야각의 변화를 구하였다. MRPA와 MRCA 구조물의 최적의 형상은 측면각이 각각 59도와 57도이었으며, 시야각은 68도와 64도이었다. 구조물의 높이는 큰 영향을 주지 않았다.

회피 기동에 강인한 수상 항적 탐색 방법 (Robust Ship Wake Search Method in the Target Evasion Environment)

  • 구본화;이영현;박정민;정석문;홍우영;김우식;임묘택;고한석
    • 한국군사과학기술학회지
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    • 제12권1호
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    • pp.8-17
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    • 2009
  • This paper proposes robust ship wake search method in the target evasion environment. Moving surface ships generate a long trailing wake in the rear of a surface ship. Wake homing torpedo sensing this wake can detect the surface target and engage it automatically. In wake homing torpedo, wake search method is important element to maximize effectiveness of wake homing torpedo. This paper proposes one-side, two-side and centering mode according to passing wake boundary scenarios. Also, wake deflection angle is deduced by using the principle of deflection angle of acoustic torpedo. The representative experimental results using monte-carlo simulation demonstrate that the searching method using one-side mode is superior to two-side and centering mode in the target evasion environment.

주 재배 작목별 한국 여성 농업인 체형 특성 (Characteristics of the Body Shape of Korean Woman Farmers by Crops)

  • 백윤정;이경숙
    • 한국의류학회지
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    • 제32권10호
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    • pp.1584-1594
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    • 2008
  • This study was to research the characteristics of the body shape of Korean woman farmers by the major crops. Four hundred ninety-five Korean woman farmers from 9 different area such as Kumi, Damyang, Iksan, Injae, Chungju, Choongju, Haman, Whasung, and Whasoon volunteered for this study. Their major crops were the rice, the pepper, the water melon, the strawberry, the wild rocambole, the sweet persimmon, the grapes, the mushroom, and the chrysanthemums. Twelve body angles were measured from archived the somatotype photographs of the front, the side, and the back. Questionnaires of SF-36 and the farmer's symptom, and the farm-work related movements were surveyed. The results were as follows; 1. Farmers had lower health levels in physical role limit, pain, vitality, and physical function than other occupational workers. 2. Most farmers acted the high-risk ergonomics motions when they worked in the farm. 3. There were significantly different on the both shoulder angles, the hip tangential line slope, the hip breadth angel, in frontal ankle-knee angle, the bending back angle, the dropping breast slope, the abdominis media angle, under the abdominis media angle, the glutea angle, under the glutea angle, and the sideward knee angle(p<.05). 4. Farmers cultivating the low plants such as the water melon, the strawberry, and the wild rocambole showed more banded vertebralis and side knee angles. Farmers cultivating the red pepper showed the dropping the left shoulder and O shape legs. Farmers cultivating the fruit trees such as the sweet persimmon and the grapes showed the less banded side knee angles than other farmer groups. 5. On comparing the same age, farmers showed the older's body shape in earlier and much more than the old living in the city.

모형자동차 충돌시험의 데이터베이스를 이용한 측면 충돌사고 재구성 (A Study on the Side Collision Accident Reconstruction Using Database of Crush Test of Model Cars)

  • 손정현;박석천;김광석
    • 한국자동차공학회논문집
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    • 제17권2호
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    • pp.49-56
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    • 2009
  • In this study, a side collision accident reconstruction using database based on the deformed shape information from the collision test using model cars is suggested. A deformation index and angle index related to the deformed shape is developed to set the database for the collision accident reconstruction algorithm. Two small size RC cars are developed to carry out the side collision test. Several side collision tests according to the velocity and collision angles are performed for establishing the side collision database. A high speed camera with 1000fps is used to capture the motion of the car. A side collision accident reconstruction algorithm is developed and applied to find the collision conditions before the accident occurs. Two collision cases are tested to validate the database and the algorithm. The results obtained by the reconstruction algorithm show good match with original conditions with regard to the velocity and angle.

초듀랄류민(A2024-T3)의 절삭거동에 관한 연구 (The Study on the Cutting Behavior of Super Duralumin(A2024-T3))

  • 전태옥;박흥식;예규현
    • 한국정밀공학회지
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    • 제9권4호
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    • pp.147-153
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    • 1992
  • This study was undertaken to investigate the cutting behaviour of super duralumin (A2024-T3) with sintered carbide tool(P20). The cutting test was carried out under different conditions such as cutting speed, cutting depth and rake angle, etc. The specific cutting force Kc and Kt of vertical and radial forces decreases as cutting speed increases, especially the decrease rate of Kt becomes larger than of Kc as cutting speed increases. Kc and Kt in small cutting depth are much affected by work-hardening of surface layer. The chip width and shear angle become layer as cutting depth increases, especially chip width at feed of 0.1mm almost approaches cutting width. Relation between the friction coefficient of chip side and tool rake angle side can make the modelization studying the built-up edge size. The shear angle model equation of super duralumin generally agree with theory of Ernst-Merchant.

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측쇄기를 가진 폴리머의 폴리이미드 소성 방법에 따른 액정 배향 효과 (Liquid crystal alignment effects by imidization methods of the polyimide on the polymer with side chain.)

  • 서대식;김형규
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 춘계학술대회 논문집 디스플레이 광소자 분야
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    • pp.177-180
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    • 2000
  • In this study, we investigated the pretilt angle generation and liquid crystal (LC) alignment by ultraviolet (UV) exposure during imidization of polyimide on the polymer with side chain. The generated pretilt angle of nematic (N) LC using in-situ photo-alignment method was smaller than that of the conventional UV photo-alignment method. Also, the generated pretilt angle of NLC tends to increase by annealing.

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아음속 유동하의 고 받음각 물체 주위의 비대칭 와류 특성 연구 (Asymmetric Vortices around a Body at High Angle of Attack Subsonic Flow)

  • 박미영;김완섭;이재우;박수형
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2008년도 춘계학술대회논문집
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    • pp.33-38
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    • 2008
  • Numerical investigation of asymmetric vortices at high angles of attack subsonic flow is performed using three-dimensional Navier-Stokes equations. A small bump has been carefully selected and attached near the nose of an ogive cylinder to simulate symmetric vortices. Selected bump shape does develop asymmetric vortices and is verified using Lamont's experimental results. By changing the angle of attack, Reynolds numbers, and Mach numbers, the characteristics of asymmetric vortices are observed. The angle of attack which contributes significantly to the generation of asymmetric vortices are over 30 degrees. By increasing Mach number and Reynolds number asymmetric vortices, hence the side forces show decreasing trend..

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