• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.61-64
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• 1998

We have investigated the effects of ultraviolet (UV) light irradiation condition and imidization temperature for the generation of pretilt angle in nematic liquid crystal (NLC) on the two kinds of the polyimide (PI) surfaces. High pretilt angle of NLC is generated with oblique p-polarized UV light irradiation of 30$^{\circ}$ on PI surface for 20 min. Also, the high pretilt angle of NLC is generated with oblique p-polarized UV light irradiation of 10-30$^{\circ}$ on PI surface at 20min. The pretilt angle of NLC decreases with increasing the imidization temperature on all rubbed PI surfaces ; the pretilt angle of NLC with oblique p-polarized UV light irradiation of 30$^{\circ}$on PI surface decreases with increasing the imidization temperature. The high pretilt angle of NLC is observed due to high photo-depolymerization reaction by low surface energy at low imidization temperature. We suggest that the pretilt angle of NLC is strongly attributed to the photo-depolymerization reaction with the UV light irradiation condition and imidization temperature.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.1
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• pp.65-72
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• 1991

For the enhancement of a comprehension in temporomandibular joint radiographs, the author has compared and analysed the roentgenographic images of the temporomandibular joint of human dry skull which was taken by submentovertex projection, panoramic radiography, oblique lateral transcranial projection, corrected anterio-posterior tomogram and corrected lateral tomogram. The obtained results were as follows. 1. The submentovertex projection represented in detail the both poles and the posterior surface of the condylar head of the mandible. 2. The oblique lateral transcranial projection represented the articular space, the outer contour of the condylar head and the position of the condylar head within the mandibular fossa, but the relationship of the temporomandibular joint was not revealed accurate, because of the oblique direction of a central ray in taking radiographs. 3. The corrected antero-posterior tomogram was superior method in representation of roent- genographic images of the superior surface and the both poles of the condylar head and the corrected lateral tomogram was considered as the most accurate method among some radiographic techniques for the interpretation of articular space and condyle-fossa relationship. 4. It was possible to observe three-dimensionally the head of condyle with the combinated use of submentovertex projection, corrected antero-posterior tomogram and corrected lateral tomogram.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.19 no.1
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• pp.151-159
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• 1989

The author has studied radiographic bony cnages of mandibular condyle head in temporomandibular disorder patients using Oblique lateral transcranial projection, Orthopantomography, and Tomography. The bony change types and the frequencies of occurrence and the incidences of bony changes in three different radiographic techniques were examined. The coincidences of bony change types between the Oblique lateral transcranial projection and the lateral part of Tomogram, the Orthopantomogram and the medial part of Tomogram were also examined. The results were as follows: 1. The mean age of patients was 31.7 years and under 40 years were 24 patients, women werw 27 patients, men were 4patients. 2. The observable case of bony changes in all three radiographic techniques were 19 cases (50%) of 38 cases and the observable cases of bony changes in only Tomography were 5 cases(13.2%) 3. The most frequent radiographic bony change type was osteophyte and next orders were flattening, erosion, concavity. 4. The positional incidences of bony change in Tomogram were 31 cases in lateral part and 27 cases in central part. 5. The coincidence of bony change types between the Oblique lateral transcranial projection and the lateral part of Tomogram was 80%, and the coincidence between the Orthopantomogram and the medial part or Tomogram was 76.0%.

• The Journal of Korean Physical Therapy
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• v.32 no.1
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• pp.52-57
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• 2020

Purpose: This study compared the muscle activities of the Vastus medialis oblique (VMO) and the Vastus lateralis (VL) at three different knee extension angles: 90°, 135°, and 180° in the sitting position. Methods: Twenty subjects between 20 and 30 years of age participated in the study. A mobile phone application called the Clinometer was used to measure the knee joint angle. Electromyography (EMG) was performed to measure the muscle activities of the VMO and VL muscles during knee isometric extension exercises. The pulling sensor was used to maintain 70% of the maximum strength of the knee extensor continuously in the sitting position. After attaching the EMG sensor, the subjects were asked to perform isometric knee extension exercises randomly among three knee extension angles (90°, 135°, or 180°) in the sitting position. One-way repeated measures analysis of the variance and a Bonferroni post hoc test was used to identify the VMO and VL muscle activity during knee extension angles among 90°, 135°, and 180°. Results: The VMO and VL muscle activities increased with increasing knee extension angle in the sitting position (p<0.01). Conclusions: Knee extension exercise at a 180° angle in the sitting position can be recommended to increase the muscle activity of the VMO and VL muscle activities efficiently.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.6
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• pp.766-772
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• 2003

The pseudospectral method for stability analysis was used to find the most influential disturbance mode for transition of plane channel flows and Blasius flow at their critical Reynolds numbers. A number of various oblique disturbance waves were investigated for their pseudospectra and resolvent norm contours in each flow, and an exhaustive search method was employed to find the disturbing waves to which the flows become most unstable. In plane Poiseuille flow an oblique disturbance with a wavelength of 3.59h (where h is the half channel width) at an angle $28.7^{\circ}$ was found to be the most influential for the flow transition to turbulence, and in plane Couette flow it is an oblique wave with a wavelength of 3.49h at an angle of $19.4^{\circ}$. But in Blasius flow it was found that the most influential mode is a normal wave with a wavelength of $3.44{\delta}_{999}$. These results imply that the most influential disturbance mode is closely related to the fundamental acoustic wave with a certain shear sheltering in the respective flow geometry.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.11 no.2
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• pp.87-95
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• 1989

The therapeutic methods and follow - up prognosis of subcondylar fractures in adults have always been sources of controversy. To improve the therepeutic results in subcondylar fractures with displacement, and especially, the bicondylar ones, the auther employ the surgical reduction using of sagittal split and oblique subcondylar osteotomy. This report is illustrated by six clinical cases.

• Journal of Korean Physical Therapy Science
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• v.23 no.1
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• pp.24-32
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• 2016

Purpose: Muscle imbalance around the knee region, especially quadriceps imbalance, is considered one of the main contributing factors to the development and progression of knee dysfunction based on the changes observed via electromyography (EMG). This study aimed to investigate the effect of vastus lateralis (VL) inhibition taping using non-elastic tape on the EMG activity of the vastus medialis oblique (VMO) and VL during isometric knee extension. Method: Thirty-three healthy young adults (11 males and 22 females) were recruited. With and without VL inhibition taping, the participants performed isometric knee extension in the sitting position for a total of 7 seconds. Result: VMO/VL EMG ratio significantly increased after VL inhibition taping (p<.05). Conclusion: These findings suggest that VL inhibition taping may contribute to VL inhibition and may help improve VMO/VL ratio in young adults. We expect VL inhibition taping to be useful in individuals with greater VL than VMO activity

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.2
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• pp.74-82
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• 2010

Fretting damage can be observed in automobile and railway vehicle, fossil and nuclear power plant, aircraft etc. In the present study, railway axle material RSA1 used for evaluation of fretting fatigue life. Plain and fretting fatigue tests were carried out using rotary bending fatigue tester with proving ring and bridge type contact pad. Through these test, the following results are obtained: 1) it is found that the fretting fatigue limit of standard specimen decreased about 37% compared to the plain fatigue limit. 2) The early crack of Shinkansen type specimens initiated in contact area and final fractured below samp=214 MPa. 3) The early crack of all TGV type specimens initiated in rounded area and fractured. 4) Tire tracks and rubbed scars were observed in the oblique crack region and fatigue crack growth region of fracture surface. 5) The wear debris is observed on the contact surface, and oblique cracks at an earlier stage are initiated in contact area. These results can be used as useful data in a structural integrity evaluation of railway axle.

• The Journal of Korean Physical Therapy
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• v.29 no.2
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• pp.80-84
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• 2017

Purpose: This study was conducted to examine the effects of different sizes of blood flow restriction areas on the thickness of the external oblique and biceps brachii. Methods: The study subjects were 52 adults who were divided into four groups that performed plank exercises over a six-week period after blood flow restriction. Changes in the thickness of the external oblique and biceps brachii were measured using ultrasonography before the experiment, then three and six weeks after the experiment. The changes in each variable over time were evaluated by repeated-measures analysis of variance (ANOVA). Results: The external oblique and biceps brachii showed significant differences in muscle thickness with regard to time and the interaction between time and each group (p<0.01), but no significant differences with regards to changes between groups (p>0.05). Conclusion: A larger blood flow restriction area resulted in a statistically significant increase in muscle thickness. The results of this study may be used as the basis for future studies and for rehabilitation in clinical practice.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.151-151
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• 2012

빗각 증착법(oblique angle deposition; OAD)을 이용하여 코팅된 알루미늄과 질화 티타늄 박막의 특성을 분석하였다. OAD는 기판과 증발원이 수평하게 위치하는 일반적인 코팅방법과 다르게 기판이 증발원과 수평하게 놓이지 않고 일정한 각으로 기울여 코팅하는 방법을 의미한다. 코팅 시 기판이 증발원과 수평하지 않으면 입사되는 증기가 일정한 각도를 유지하기 때문에 코팅되는 박막의 구조가 달라지고 이로 인해서 물리적 특성도 변하게 된다. 본 연구에서는 음극아크와 스퍼터링을 이용하여 각각 질화 티타늄과 알루미늄을 빗각으로 코팅하여 박막의 미세구조와 물성 변화를 관찰하였다. 스퍼터링을 이용하여 빗각 코팅된 알루미늄의 경우, 박막의 구조가 치밀해지고 표면 조도가 낮아지는 현상이 관찰되었다. 알루미늄 박막의 치밀도와 표면조도 향상은 가시광선 영역의 반사율을 높이는 효과가 있었다. 강판에 알루미늄을 코팅하여 염수분무를 실시한 결과, 치밀한 조직으로 인해서 내식성이 향상되는 결과를 보였다. 음극 아크를 이용하여 빗각 코팅된 질화 티타늄 박막에서 기판과 수직하지 않고 일정한 각도로 기울어진 주상 조직이 관찰되었다. 기판에 수직하게 성장된 질화 티타늄 박막과 비교하여 기울어진 주상 구조의 박막은 경도가 높아지는 특성 변화가 관찰되었다. 빗각 증착법을 이용하여 박막의 조직, 물성 등을 제어할 수 있었다. 박막에 다양한 기능을 부여하는 코팅방법으로 빗각 증착법이 활용될 수 있을 것으로 판단된다.