• 한국태양에너지학회 논문집
• /
• 제35권4호
• /
• pp.25-34
• /
• 2015

This research is carried out to provide fundamental data for the design of solar photovoltaic systems. Methodologically, the solar radiation installations from 10 different pyreheliometers are measured, which are set up at 6 and 4 different levels of tilts and azimuth, respectively. Maximum of a yearly accumulated solar radiation is $1,569.8kWh/m^2{\cdot}year$ with a tilt angle of $30^{\circ}$ and an azimuth angle of $0^{\circ}$(south), $1,558.5kWh/m^2{\cdot}year$ with an azimuth angle of $0^{\circ}$(south) in combination of a tilt angle of $35^{\circ}$. This paper estimates that in designing fixed solar photovoltaic systems with a tilt angle of $12.5^{\circ}{\sim}50^{\circ}$(south) and a tilt angle of $35^{\circ}$ in combination of an azimuth angle of $S45^{\circ}W{\sim}S45^{\circ}E$, a tilt angle and an azimuth angle will cause a maximum 6.8% and 9.9% of efficiency variation respectively, depending on a installed solar module's angle and direction.

• 한국운동역학회지
• /
• 제14권1호
• /
• pp.51-63
• /
• 2004

The purpose of this study was to investigate a three dimensional kinematic variables about the last stride and the release phase of the throwing technique for female javelin throwers. For the motion analysis, Six female javelin throwers were used as subjects. Three-dimensional coordinates were collected using the Kwon3D Motion Analysis Package Version 2.1 Program. Two S-VHS Video Cameras were used to record the locations and orientations of control object and the performances of the subjects at a frequency of 6.0 HZ. After the kinematic variables such as the time, the distance, the velocity, and the angle were analyzed about the last stride and release phase, the followings were achieved; 1. For the effectively javelin throwing, the subjects appeared to do long the approach time in the phasel of landing phase, and short the delivery time in release phase 2. In the release event, the other subjects except for subject A appeared to throwing in the lower condition than the height of themselves. This result showed to slow the projecion velocity. 3. For increase the projection vcelocity of the upper extremity joint in the release event, it appeared to do extend rather the shoulder angle than increase the extension of elbow joint. 4. The body of COG angle showed to gradually increase nearly at the vertical axis in the release event. But the front lean angle of trunk showed a small angle compare to increase of the body of COG angle. Therefore for the effectively momentum transmission of the whole body in the javelin, the front and back lean angle of trunk appeared to do fastly transfer the angle displacement in the arch posture or the crescent condition during the deliverly motion of the release phase.

• 대한치과교정학회지
• /
• 제24권2호
• /
• pp.395-403
• /
• 1994

To find out the antero-posterior morphology of the upper face in Angle's class III malocclusion patients, 90 patients, adults in Heilman's Dental age, were used as samples and following results were obtained after the relative comparision of antero-posterior relationship of upper facial structures between Angle's class I malocclusion patients and Angle's class III malocclusion patients and of antero-posterior size of upper facial structures to horizontal and vertical structures in each patients. 1. After comparison of the distance from PMV line to anterior margin of maxillary sinus and cheek, which determines the antero-posterior position of the upper face, upper face in Angle's class III patients are underdeveloped relative to Angle's class I patients. The distance between orbitale and anterior margin of maxillary sinus were greater in Angle's class I patients, whic implies thart the upper face in Angle's class III are depressed. 2. Antero-posterior dimension of anterior cranial base from PMV line and vertical dimension of upper face are statistically insignificant between two groups. After comparing antero-posterior position of upper face to anterior cranial base, the upper face in Angle's class Et patients are depressed antero-posteriorly in relation to anterior cranial base. Following the comparision of antero-posterior position of upper face in relation to vertical dimension of upper face, the upper face in Angle's class III patients seem to be narrow antero-posteriorly

• 대한기계학회논문집A
• /
• 제40권12호
• /
• pp.1013-1019
• /
• 2016

CFRP는 탄소섬유를 기반으로 수지를 합침하여 제조된 복합소재로, 높은 비 강도와 경량성을 지녀 다양한 분야들에서 널리 사용되어지고 있다. 특히 일방향 탄소섬유는 적층 각도를 적용할 수 있으며 이때 적용된 적층 각도로 구성된 CFRP는 적층 각도가 없는 것보다 더 높은 강성을 가지고 있다. 본 논문에서는 적층 각도 변화에 따른 CFRP 소형 인장시험편의 크랙 전파와 파괴거동에 관한 것으로, 각 적층 각도에 따른 크랙 성장의 특성을 고찰한다. 적층 각도가 증가함에 따라 최대 응력 값이 작게 나타나고 크랙 전파가 더디게 나타나지만, 적층 각도 $60^{\circ}$를 기점으로 그 응력이 다시 증가되므로 서, 적층 각도에 따른 한계를 보이고 있다. 본 연구결과는 기계구조물의 CFRP사용에 있어 구조물내의 결함이 발생하였을 때의 피로파괴 가능성을 검증하는 자료로 사용될 수 있다고 사료된다.

• 한국정밀공학회지
• /
• 제4권3호
• /
• pp.44-51
• /
• 1987

In metal cutting various types of chips are produced in consequence of cutting conditions. Flow-type chips have been studied in most cases because they are easier to be analyzed, but the actual surfaces of chips are not smooth, but crushed. This paper deals with saw-toothed chips, special types of flow-type chips, which have deep concaves and high convexes and sharp angles on the free surface. I tried to establish the theory of saw-toothed chip mechanism through experimental observation, that is, the mathmatical model of the cutting energy and cutting mechanism through the geometrical observation of the chips by using a microscope. The results obtained are as follows: 1. The mechanism of saw-toothed chips is diffenent from that of general flow-chips. 2. In the case of saw-toothed chips, the shear angle must be measured by the hypotenuse angle and the rake angle, and the shear angle is more affected by the rake angle than by the hypotenbuse angle. 3. The friction angle is represented by .beta. = . pi. /4+ .alpha./ sub n/- .phi. which is different from Merchant's equation. 4. The pitch and the slip are greatly influenced by depth of cut, but the influence of the rake angle on it is small. 5. The normal stress and the shear stress on the shear plane decrease with the increase of the cutting depth, and they are almost independent on the variation of a rake angle. 6. The unit friction energy on the tool face, the unit shear energy on the shear plane, and the total cutting energy per unit volume decrease with the increase of rake angle and cutting depth.

• 대한물리의학회지
• /
• 제10권2호
• /
• pp.29-34
• /
• 2015

PURPOSE: The purpose of present study was to introduces an exceptional case in measurement methods (CVA, CRA and Cobb angle) to identify the FHP with verified reliability and validity. Subjects: Three males aged 30 years were recruited: A Normal, B and C who have FHP. METHODS: All the subjects were measured CVA, CRA and Cobb angle with the Photogrammetry and Radiography. RESULTS: The results revealed that it is not enough for measurement methods to identify the FHP using CVA, CRA and Cobb angle. On Photogrammetry values; CVA had $65^{\circ}$, CRA was $148^{\circ}$ of Normal subject A and CVA had $61^{\circ}$, CRA was $149^{\circ}$ of FHP subject B and CVA had $51^{\circ}$, CRA was $149^{\circ}$ of FHP subject C. On Radiography values; CVA had $73^{\circ}$, CRA was $148^{\circ}$ and Cobb was $50^{\circ}$ of Normal subject A and CVA had $70^{\circ}$, CRA was $150^{\circ}$ and Cobb was $53^{\circ}$ of FHP subject B and CVA had $61^{\circ}$, CRA was $153^{\circ}$ and Cobb was $31^{\circ}$ of FHP subject C. CONCLUSION: The reliable CVA, CRA and Cobb angle use methods from the previous studies might not be suitable for the diagnose the FHP. We think that it is necessary to have more detailed evaluation methods and the radiography is also needed for clear evaluations because of some possible exceptions.

• 한국해양공학회지
• /
• 제35권5호
• /
• pp.313-326
• /
• 2021

A submerged body with varied control inputs can execute large drift angles and large angles of attack, as well as basic control such as straight movement and turning. The objective of this study is to analyze the dynamic characteristics of a submerged body comprising six thrusters and six control planes, which is capable of a large drift angle and angle of attack motion. Virtual captive model tests via were analyzed via computational fluid dynamics (CFD) to determine the dynamic characteristics of the submerged body. A test matrix of virtual captive model tests specialized for large-angle motion was established. Based on this test matrix, virtual captive model tests were performed with a drift angle and angle of attack of approximately 30° and 90°, respectively. The characteristics of the hydrodynamic force acting on the horizontal and vertical surfaces of the submerged body were analyzed under the large-angle motion condition, and a model representing this hydrodynamic force was established. In addition, maneuvering simulation was performed to evaluate the standard maneuverability and dynamic characteristics of large-angle motion. Considering the shape characteristics of the submerged body, we attempt to verify the feasibility of the analysis results by analyzing the characteristics of the hydrodynamic force when the large-angle motion occurred.

• 한국지반공학회논문집
• /
• 제23권8호
• /
• pp.69-76
• /
• 2007

테이퍼말뚝의 연직거동은 지반의 응력상태와 내부마찰각, 말뚝의 벽면마찰각, 말뚝의 테이퍼 각도에 영향을 받는다. 본 논문에서는 테이퍼 각도가 말뚝의 연직거동에 미치는 영향을 조사하기 위해서 가압토조를 이용한 모형말뚝시험을 실시하였다. 시험결과에 따르면 말뚝의 테이퍼 각도가 커질수록 주면마찰력은 커지고 선단지지력은 감소하였으나, 단위 선단지지력의 경우 보통 상대밀도의 지반에서는 말뚝의 테이퍼 각도에 비례해서 증가하였으나 조밀한 지반에서는 테이퍼 각도에 따라 감소하였다. 그리고 말뚝의 전체지지력에 대한 주면마찰력의 비율은 테이퍼 각도가 커짐에 따라 그리고 지반의 상대밀도가 작아짐에 따라 증가하는 경향을 보였다. 또한 말뚝의 단위 체적당 전체지지력은 지반이 느슨할 때는 테이퍼 각도에 따라 증가했지만 조밀한 지반에서는 테이퍼 각도에 따라 감소하였다. 따라서 테이퍼말뚝은 조밀한 지반보다는 느슨한 지반에서 더 경제성이 있는 것으로 나타났다.

• Journal of Korean Neurosurgical Society
• /
• 제66권6호
• /
• pp.703-715
• /
• 2023

Objective : This retrospective study investigated the factors that affect cage obliquity angle despite orthogonal maneuvers performed during oblique lateral interbody fusion (OLIF) and assessed the relationship between cage obliquity angle and radiological outcomes post-surgery. Methods : Twenty-nine males who underwent L4-L5 OLIF for lumbar degenerative disease between 2019 and 2021 with a followup duration greater than 12 months were analyzed. Radiological parameters were measured including psoas muscle volume, total psoas area index (total psoas muscle area [cm²]/height squared [m²]), distance from the iliac artery to the origin of the psoas muscle (DIAPM), angle between the origin of the psoas muscle and the center of the vertebral disc (APCVD), iliac crest height, disc height, lumbar flexibility (lumbar flexion angle minus extension angle), cage location ratio, cage-induced segmental lumbar lordosis (LL) (postoperative index level segmental LL minus used cage angle), foraminal height changes, fusion grade. Results : DIAPM, APCVD, iliac crest height, postoperative index level segmental LL, and cage-induced segmental LL were significantly correlated with OLIF cage obliquity angle. However, other radiological parameters did not correlate with cage obliquity. Based on multiple regression analysis, the predictive equation for the OLIF cage obliquity angle was 13.062-0.318×DIAPM+0.325×1APCVD+0.174×iliac crest height. The greater the cage obliquity, the smaller the segmental LL compared to the cage angle used. Conclusion : At the L4-L5 level, OLIF cage obliquity was affected by DIAPM, APCVD, and iliac crest height, and as the cage obliquity angle increases, LL agnle achievable by the used cage could not be obtained.

• 대한물리치료과학회지
• /
• 제31권2호
• /
• pp.52-62
• /
• 2024

Background: This study was to investigate effects of narrow squat exercise according to ankle angle of Toe in 10° and Toe out 10° on women with genu varum. Design: Randomized Controlled Trial or Cross-sectional Study. Methods: 30 adult women with genu varum participated in this study. All subjects were randomly assigned to 15 people of narrow squat exercise in ankle angle of Toe in 10° group (TI) and 15 people of narrow squat exercise in ankle angle of Toe out 10° group (TO). The narrow squat exercise program was conducted three times a week for six weeks. The distance between the knees was measured by using Digital Vernier Caliper. The quadriceps angle (Q-angle) was measured by using Goniometer. The stride length and propulsion were measured through G-Walk Results: Both TI and TO groups showed effective significant differences in distance between the knees, Q-angle, and propulsion (p<.05). There was no significant difference in stride length (p>.05). Left leg propulsion was found to be significantly more effective in TI group than in TO group (p<.05). Conclusion: These results suggested that narrow squat exercise according to ankle angle of toe in 10° and toe out 10° was effective for genu varum. However, compared to TO group, TI group was more effective in gait propulsion. It is considered that narrow squat exercise in ankle angle of Toe in 10° can be suggested as an effective intervention method for women with genu varum.