• 한국세라믹학회지
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• 제31권10호
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• pp.1099-1106
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• 1994

It is suggested that the microstructural toughening process in the initial rising portion of R-curves observed in polycrystalline alumina should be different from the grain bridging mechanism identified in the long crack regime. Microcracking in the advancing crack front seems to be a prerequisite for the development of unbroken bridging ligaments behind the crack tip. In order to test such a proposition, attempts were made to identify experimentally the presence of microcracks in the frontal zone of propagating cracks. In-situ observation is made of crack growth in a miniature double cantilever beam specimen of a average grain size of 10 ${\mu}{\textrm}{m}$ alumina. Presence of a few microcracks was identified in front of crack tip on the propagating crack plane. The R-curves were re-evaluated based on the observation.

• 한국전문물리치료학회지
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• 제9권1호
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• pp.53-61
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• 2002

The purpose of this study was to compare the body alignment during standing on level and wedge board. Twenty healthy college students (8 females, 12 males) were evaluated in this study. Diagnostic contourline potographic imaging system (Model JTC-1, Jodang Trading Co.) was used to measure body alignment. Sagittal and frontal plane images were used to analyze the body alignment. The result showed that the cervical and lumbar lordotic curve significantly decreased during standing on wedge board when compared with standing on level. On the other hand, thoracic kyphosis significantly increased during standing on wedge board. There was no significant difference in body alignment according to gender, weight, and height. Clinically, patients with low back pain and severe lordosis may be affected by heel wedge. Further study is needed to identify whether the standing on wedge board can change the body alignment in patients with low back pain and spinal deformity.

• 대한기계학회논문집A
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• 제21권12호
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• pp.2096-2105
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• 1997

A parallel approach using a network of engineering workstations is presented for the efficient computation in the elastoplastic analysis of strip rolling process. The domain decomposition method coupled with the frontal solver for elimination of internal degrees of freedom in each subdomain is used. PVM is used for message passing and synchronization between processors. A 2-D plane strain problem and the strip rolling process are analyzed to demonstrate the performance of the algorithm and factors that have a great effect on efficiency are discussed. In spite of much communication time on the network the result illustrates the advantages of this parallel algorithm over its corresponding sequential algorithm.

• The Journal of Korean Physical Therapy
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• 제22권6호
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• pp.21-28
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• 2010

Purpose: The purpose of this study was to investigate the kinematic adaptation of head and trunk to ascend stairs and a ramp. Subjects were healthy young adults. Three-dimensional kinematic patterns of head and trunk movements were examined during stair climbing and steeper ramp climbing. Methods: Fourteen young subjects with no history of chronic or acute musculoskeletal, cardiovascular or respiratory disorders took part in this experiment. Kinematic data were collected using a 6 camera Vicon system (Oxford Metrix, Oxford, England). Repeated measures ANOVA analyses were used to investigate the effect of gait mode on kinematics of the head and trunk. Results: The angle of the trunk while ascending stairs or a ramp was modified in three human planes (p<0.05). The angle of head and neck during the ascending of stairs or a ramp was not changed in the sagittal plane but was changed in the frontal and transverse planes (p<0.05). Conclusion: This study describes and discusses some basic kinematic mechanisms underlying the pattern of head and trunk changes during stair and ramp climbing and showed that postural adaptation of the head and trunk is necessary to maintain balance.

• International Journal of Fluid Machinery and Systems
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• 제2권2호
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• pp.172-178
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• 2009

This paper reports on an investigation (using RSM with commercial CFD software) of the performance characteristics of the impeller in a centrifugal pump. Geometric parameters of vane plane development were defined with the meridional shape and frontal view of the impeller. The parameters are focused on the blade-angle distributions through the impeller in a fixed meridional geometry. For screening, a $2^k$ factorial design has been used to identify the important design parameters. The objective functions are defined as the total head rise and the total efficiency at the design flow-rate. From the $2^k$ factorial design results, it is found that the incidence angles and the exit blade angle are the most important parameters influencing the performance of the pump.

• 한국유체기계학회 논문집
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• 제11권3호
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• pp.36-42
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• 2008

In this paper, the performance characteristics of the impeller in a centrifugal pump were investigated using DOE(Design of Experiment) with commercial CFD software. Geometric parameters of vane plane development were defined with the meridional shape and frontal view of the impeller. The incidence angles and the exit blade angle were selected as main parameters using 2k factorial and the influences of selected design parameters were examined through the optimization process using RSM.

• 대한두개안면성형외과학회지
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• 제12권2호
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• pp.81-85
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• 2011

Purpose: Nasal bone fracture is the most common facial fracture. Although nasal bone fractures are considered to be minor injuries, the incidence of post-traumatic nasal deformity remains high. This study is designed to support management and patient satisfaction by classifying the simple nasal bone fracture, and survey the care method and result, which is compared with other studies. Methods: From May 2008 to April 2010, 334 patients with simple nasal bone fractures visited our hospital. The incidence, cause, types of nasal bone fracture, treatment, and complications are analyzed according to clinical examination, patient's record and radiographic images. Results: The mean age of patients was 30 years old, with 74% of the patients having been male, and 26% were female. The highest incidence of this fracture was between late teens to late twenties. The causes of nasal bone fracture were the following: having slipped or fallen down (39%), violence (16%), sports accident (14%), traffic accident (11%), industrial accident (6%), and others (16%). Patient's radiographic images were analyzed by Stranc and Robertson classification, frontal impact plane I was 38%, plane II was 16%, plane III was 1%, lateral impact plane I was 21%, plane II was 21%, and plane III was 3%. On average, surgical treatment was performed 7.2 days after trauma under general anesthesia. Closed reduction of nasal bone fracture was performed in 99% of patients. In patients with septal injuries, septal management was performed in 76.7% of cases. Aesthetic surgery was done on same time in 24% of patients. There were some complications, such as residual nasal deformity (7.2%), nasal obstruction (0.9%) and hyposmia (0.3%). Conclusion: According to this study, nasal bone fractures occurred commonly in physically active age groups (age 15~29 years), as a result of having slipped or fallen down, at afternoon and at night time. And it could be treated successfully by closed reduction and septoplasty by 7 days after trauma.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제23권2호
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• pp.115-123
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• 2001

The primary method of diagnosis in craniofacial deformity patient is used by gross inspection. The study for objective analysis and evaluation in Korean maxillofacial soft tissue portions is rare and our normals have been based on Caucasian such as American. But it is difficult to apply it to ours so we studied the frontal photometric measurements for maxillofacial Korean normals. The photograph were taken with the subject sitting in head position parallel with interpupillary plane to the floor. During taking pictures, facial analyser by Obwegeser in Martin was used for correct measurements. 54 male and 57 female ages 14 to 15 years were selected from a group of 111 healthy middle school students in Inchon. 1. The vertical measurements in glabella-subnasale, subnasale-stomion and stomion-menton in the male were higher than in the female subjects in $14{\sim}15$ years old Korean, so middle and lower third face were higher than those of female(p<0.05). 2. The horizontal measurements of female was higher than those of male in the rt. and It. eye width but smaller in nose width and lip width(p<0.05). 3. There was no significant difference in gender compared with soft cheek and mention angle measurements When our reports were compared with american white population, the vertical proportions in Korean normals were similar to american and the line measurements in middle facial length, nose width and intercanthal distance were higher than those of american.

• 대한두개안면성형외과학회지
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• 제11권2호
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• pp.77-84
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• 2010

Purpose: The nasal bones are the most common fracture sites of the facial bones, and a careful reduction may still result in secondary deformities, such as saddle nose, deviated nose, hump nose etc, requiring secondary cosmetic rhinoplasty. Therefore, this study examined the clinical characteristics of nasal bone fractures to propose guidelines for patient selection and surgical procedures to achieve more satisfactory results and to prevent secondary deformities with simultaneous augmentation rhinoplasty and bony reduction. Methods: The study was based on 26 out of 149 nasal bone fracture patients who underwent simultaneous augmentation rhinoplasty with bony reduction between May 2008 and April 2009. Retrospective analysis was performed according to the clinical data, surgical techniques and postoperative results. Results: Of the 26 patients, there were 15 males and 11 females. The incidence according to the Stranc's classification revealed that 62% of patients were injured by a frontal impact and 38% by a lateral impact. Frontal impact plane I (50%) was the most frequent type. At the follow up, 18 (81.2%) out of 22 patients were satisfied with their postoperative outcome, and the remaining 4 patients were fair. No one was dissatisfied. However, 5 cases in 3 patients (23%) had some complications; minimal implant deviation in 2 cases, minor irregularity on the nasal dorsum in 2 cases and palpable implant movement under palpation in 1 case. None of these cases required surgical correction. Conclusion: With the proper guidance, simultaneous augmentation rhinoplasty with bony reduction can prevent secondary deformities and satisfy the cosmetic outcomes.

• 한국산학기술학회논문지
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• 제20권3호
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• pp.224-230
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• 2019

본 연구의 목적은 이마면에서 엉덩관절 위치에 따라 배근육들의 근활성도를 측정하여 비교함으로 이마면에서 엉덩관절의 위치가 배근육들의 근활성도에 영향을 미치는지 알아보는 것이다. 연구방법은 20대의 건강한 남녀 26명을 대상으로 엉덩관절 중립, 모음, 그리고 벌림 자세에 따라 교각운동을 하였을 때 표면 근전도 장비를 이용하여 양쪽 배곧은근과 배바깥빗근, 배속빗근의 근활성도를 비교하였다. 통계 방법은 반복측정 일요인 분산분석을 실시하였고, 유의수준은 0.05로 하였다. 연구 결과 배바깥빗근과 배속빗근은 이마면에서 엉덩관절 위치에 따라 유의한 차이가 있었고, 배곧은근은 유의한 차이가 없었다. 양쪽 배바깥빗근과 왼쪽 배속빗근은 엉덩관절 중립자세보다 엉덩관절 모음 자세에서 근활성도가 유의하게 증가하였으며 오른쪽 배속빗근은 엉덩관절 벌림 자세보다 엉덩관절 모음 자세에서 근활성도가 유의하게 증가하였다. 본 연구를 통해 엉덩관절 모음 자세가 다른 자세들에 비해 안정화 운동에 더욱 효과적일 수 있다는 것을 알 수 있었고, 안정화 운동 프로그램을 고안할 때 운동의 강도를 조절하기 위해 이마면에서 엉덩관절의 위치에 대한 요소를 적용할 수 있을 것이다.