• Journal of the Korean Wood Science and Technology
• /
• 제29권3호
• /
• pp.36-46
• /
• 2001

This study was to find a way of reusing wood and plastic wastes, which considered as a troublesome problem to be solved in this age of mass production and consumption, in manufacturing wood fiber-polypropylene fiber composite panel. And the feasibility of this composite panel as a substitute for existing headliner base panel of automobile was also discussed, especially based on physical and mechanical performance. Nonwoven web composite panels were made from wood fiber and polypropylene fiber formulations of 50 : 50, 60 : 40, and 70 : 30, based on oven-dry weight, with densities of 0.4, 0.5, 0.6, and 0.7 g/$cm^3$. At the same density levels, control fiberboards were also manufactured for performance comparison with the composite panels. Their physical and mechanical properties were tested according to ASTM D 1037-93. To elucidate thickness swelling mechanism of composite panel through the observation of morphological change of internal structures, the specimens before and after thickness swelling test by 24-hour immersion in water were used in scanning electron microscopy. Test results in this study showed that nonwoven web composite panel from wood fibers and polypropylene fibers had superior physical and mechanical properties to control fiberboard. In the physical properties of composite panel, dimensional stability improved as the content of polypropylene fiber increased, and the formulation of wood fiber and polypropylene fiber was considered to be a significant factor in the physical properties. Water absorption decreased but thickness swelling slightly increased with the increase of panel density. In the mechanical properties of composite panel, the bending modulus of rupture (MOR) and modulus of elasticity (MOE) appeared to improve with the increase of panel density under all the tested conditions of dry, heated, and wet. The formulation of wood fiber and polypropylene fiber was considered not to be a significant factor in the mechanical properties. All the bending MOR values under the dry, heated, and wet conditions met the requirements in the existing headliner base panel of resin felt.

• 대한물리치료과학회지
• /
• 제10권1호
• /
• pp.222-231
• /
• 2003

The ACL(Anterior cruciate ligament) is the smallest of the four main ligaments of the knee, but it is the primary stabilizer. Injuries have a tendency to occur when the foot is firmly planted and the knee is twisted. Any sports that requires acceleration, change of direction and deceleration can increase the chances of suffering an ACL tear. The incidence of severe knee sprains that involve the ACL are at an all-time high. Since 1980, the number of these injuries have increased at least three-fold. Although the rate of increase has been much less dramatic since the middle 1980s, even the ultra-modem releasable ski binding has not been able to start reducing the incidence of ACL injuries. An ACL injury prevention program developed for downhill skiers by the Vermont Safety Research group emphasized increasing awareness of situations that can potentially result in an ACL injury and pre-planning strategies if events, leading to these situations, begin to fall in place. As part of the above study by Ettlinger et al., an educational prevent program was developed to teach these principles and thus reduce the rate of serious knee injuries. Four thousand instructors and patrol at 20 ski resorts who received the training had a 62% decline in serious knee injuries compared to a similar group that did not receive this training. Whenever you fall, try not to fully straighten your legs. Don't try to get up until you've stopped sliding(unless you are try to avoid an obstacle or other skier). When you're down, stay down. And don't land on your hand. So, if you feel yourself falling: arms forward, ski plates together, hands over knee. Then you will be able to save your ACL.

• 대한통합의학회지
• /
• 제3권4호
• /
• pp.61-67
• /
• 2015

Purpose : The purpose of this study was to find out the effect of exercise on the angle and distance between scapular stability and McKenzie stretch exercise. Method : 30 volunteers took part in this experiment and we divided into three groups(experimental group A, experimental group B, control group C). Experimental group A performed scapular stabilization exercise and experimental group B performed McKenzie neck stretching exercise and control group didn't perform any exercise. Experimental group(A, B) received a total of 12 exercise session over a 4 week period (three times per week). Posture and craniovertebral angle changes of the neck using GPS measurements reported. Result : The CVA and distance change after exercise were significantly reduced in the experimental group A and B. Conclusion : Therefore, we have confirmed through experiments reducing a CVA and distance between scapular stabilization and McKenzie neck stretching exercises, whereby we would also be helpful to ensure the treatment of forward head posture.

• 한국학교ㆍ지역보건교육학회지
• /
• 제6권
• /
• pp.117-126
• /
• 2005

This study attempted to extract a suggestive point to help the design of a program, which is used to promote physical activities, by applying a social cognitive theory based on literature review on the physical activity based on a social cognitive theory. This study considers 10 journal articles that used a social cognitive theory, physical activity, and exercise as the major variable using the EBSCOhost Academic Search Premier and Educator's Reference Desk (ERIC). The type of papers was analyzed using a certain criterion, which can be configured according to the number of each year's papers, characteristics of research subjects, application type of a social cognitive theory, and classification of the application of objects in a social cognitive theory. The characteristics of each year's papers presented no specific characteristics for each year's papers, but the study in 2004 especially presented a high level. The characteristics of research subjects presented four highest cases in the case of the college student, and there were zero cases for children. The application type of studies on physical activities using a social cognitive theory can be largely classified as three types. The results of the measurement using a sectional investigation for SCT objects were 2 cases, the application of SCT for promoting physical activities was 1 case, and the demonstration of evaluation for the effect of SCT objects presented 8 highest cases. Although the social cognitive theory in the characteristics of the classification of object applications can be classified as 10 objects, there were no cases that used 10 all objects, partial applications of the object were measured in 8 studies, and two cases presented no detailed considerations on the object. Most of studies used a part of the object where the application of self-efficacy were measured by 8 highest cases. In addition, there were no measurements on the situation, observation learning, answer and response, and self-management. The elements of attitude, cognitive activity, self-efficacy, and handicaps among the SCT object were commonly used, and studies that the self-efficacy largely affects on the promotion of physical activities presented the main current.

• Advances in concrete construction
• /
• 제16권6호
• /
• pp.291-302
• /
• 2023

As the first part of the body that strikes the ground during running, sports shoes are especially important for improving performance and reducing injuries. The use of new nanotechnology materials in the shoe's sole that can affect the movement angle of the foot and the ground reaction forces during running has not been reported yet. It is important to consider the material of the sole of the shoe since it determines the long-term performance of sports shoes, including their comfort while walking, running, and jumping. Running performance can be improved by polymer foam that provides good support with low energy dissipation (low energy dissipation). Running shoes have a midsole made of ethylene propylene copolymer (EPP) foam. The mechanical properties of EPP foam are, however, low. To improve the mechanical performance of EPP, conventional mineral fillers are commonly used, but these fillers sacrifice energy return. In this study, to improve the magnificence of physical education training with nanotechnology, carbon nanotubes (CNTs) derived from recycled plastics were prepared by catalytic chemical vapor deposition and used as nucleating and reinforcing agents. As a result of the results, the physical, mechanical, and dynamic response properties of EPP foam combined with CNT and zinc oxide nanoparticles were significantly improved. When CNT was added to the nanocomposites with a weight percentage of less than 0.5 wt%, the wear resistance, physical properties, dynamic stiffness, compressive strength, and rebound properties of EPP foams were significantly improved.

• 한국전자거래학회지
• /
• 제14권4호
• /
• pp.267-286
• /
• 2009

자동차부품산업에 속한 대부분의 기업은 완성차 조립을 위한 공급기업과의 협력에 있어 공급사슬관리시스템을 필요로 하고 있다. 자동차부품산업은 1차, 2차, 3차 공급업체와 같은 계층적 구조의 산업 특성을 가지고 있다. 최근 RFID 기술을 적용한 새로운 구현사례가 통합된 정보시스템 구현이 요구되는 다양한 영역에서 나타나고 있다. 특히 자동차부품산업의 공급사슬환경은 유비쿼터스환경으로 전환되고 있다. 자동차부품산업에 속한 대부분의 기업은 비즈니스 프로세스의 단축, 거래정보의 공유, 그리고 거래당사자간의 협업관계를 증진하기 위해 RFID기반의 공급사슬관리 구현에 관심이 높다. 본 연구는 제품의 입고, 출고, 재고관리와 같은 자동차부품산업의 물류분야에 RFID 기술을 구현하고자 한다. 연구의 목적은 유비쿼터스 컴퓨팅환경에서 u-SCM 시스템에 적용된 RFID를 활용하여 공급사슬네트워크의 협업관계를 증진하기 위한 것이다. 본 논문의 기여는 UML 기법을 적용하여 RFID기반의 SCM 시스템을 설계하고 구현함으로써 기존 프로세스를 새로운 프로세스로 전환하는 새로운 시스템 접근방안을 제안하는 것이다.

• 보존과학회지
• /
• 제28권4호
• /
• pp.329-341
• /
• 2012

마애화령석지장은 해안가에 인접해 있고 해수에 의해 주기적으로 일정 부분이 침수되는 특수한 입지적 조건에 있다. 마애불을 구성하는 암석은 중립질 또는 조립질을 띠는 흑운모화강암으로 내구성이 강한 편이나, 암석 내부에 침투한 염용액과 주변 환경과의 복잡한 상호작용에 의해 구성암석의 색과 강도 및 내구성 등 물성이 변화된 상태이다. 마애불을 이루는 암석은 염(NaCl)결정화 작용에 의한 표면층 박리박락이 심각하다. 박리박락(14.6%)은 해수의 주요 경계면을 중심으로 대기에 상시 노출되는 상부에 집중되어 있다. 반면, 해수에 의해 주기적으로 침수되는 암괴 하부는 오염물이 침착되어 흑화층을 나타내며 이와 함께 갈색변색과 생물오염이 중첩된 상태이다. 표면 오염 및 변질은 흑색 변색(29.2%), 황색 변색(14.1%), 갈색 변색(4.4%), 녹색 변색(2.9%)의 순으로 높은 훼손율(50.5%)을 나타냈다. 또한 해수면을 경계로 상부가 해수에 침수되는 하부보다 초음파 속도가 낮고 편차가 커 많은 물성 변화가 있었음을 알 수 있으며, 특히 해수 침투 경계면의 표면 물성이 취약함을 확인하였다.

• E2M - 전기 전자와 첨단 소재
• /
• 제16권9호
• /
• pp.64.1-64
• /
• 2003

A metal-ferroelectric [SrBi$_2$Ta$_2$O$\_$9/ (SBT)-high-k-insulator(PrOx)-semiconductor(Si) structure has been fabricated and evaluated as a key part of metal-ferroelectric-insulator-semiconductor-field-effect-transistor MFIS-FET memory, aiming to improve the memory retention characteristics by increasing the dielectric constant in the insulator layer and suppressing the depolarization field in the SBT layer. A 20-nm PrOx film grown on Si(100) showed both a high of about 12 and a low leakage current density of less than 1${\times}$ 10e-8 A/$\textrm{cm}^2$ at 105 MV/cm. A 400-nm SBT film prepared on PrOx/Si shows a preferentially oriented (105) crystalline structure, grain size of about 130 nm and subface roughness of 3.2 nm. A capacitance-voltage hysteresis is confirmed on the Pt/SBT/PrOx/Si diode with a memory window of 0.3V at a sweep voltage width of 12 V. The memory retention time was about 1 104s, comparable to the conventional Pt/SBT/SiO$\_$x/N$\_$y/(SiO$\_$N/)/Si. The gradual change of the capacitance indicates that some memory degradation mechanism is different from that in the Pt/SBT/SiON/Si structure.

• 대한물리의학회지
• /
• 제5권4호
• /
• pp.527-534
• /
• 2010

Purpose : The application of tape to modulation of pain and muscular excitability has become common clinical practice among musculoskeletal physical therapy. However, the techniques of the tape application has been relied on empirical evidence in preference to the neurophysiological evidence. Thus, the mechanism of taping has to be elucidated further. The aim of this study was to determine whether elastic and non-elastic taping across a muscle does indeed change ${\alpha}$-motor neuron excitability. Methods : The study was performed on 10 neurologically healthy adults. Two different types of tape were applied to skin overlying gastrocnemius. The elastic tape stretched up to 120% of its original length but non-elastic tape didn't stretched up of its original length. The tape applied across the direction on thickest part of the gastrocnemius. The ${\alpha}$-motor neuron excitability of the gastrocnemius was assessed using the gastrocnemius H-reflex. The amplitude of the M-wave and H-reflex were measured across three conditions: before tape application, with tape and with the tape removed. Results : No significant changes of the excitability of the ${\alpha}$-motor neuron were obtained across three condition, either in the elastic and non-elastic tape. Conclusion : From the results, I could come to the conclusion that further clinical work will be required.

• The Journal of Korean Physical Therapy
• /
• 제26권5호
• /
• pp.324-330
• /
• 2014

Purpose: The aim of the current study was to compare the muscle architecture of lower extremity using rehabilitative ultrasound imaging (RUSI) in young adults in Seoul and Hanoi. Methods: The study design was a comparative study of muscle cross-sectional area of lower extremity. Sixty healthy young subjects (Seoul group: 30, Hanoi group: 30) participated in this study. Real-time B-mode RUSI with a 7.5MHz linear transducer was used for measurement of cross-sectional area, pennation angle, and muscle thickness of the rectus femoris, tibialis anterior, and medial gastrocnemius muscles. Independent t-test was used for statistical analysis. Results: Significant difference in cross sectional area of rectus femoris was observed between Korean young adults and Hanoi young adults (p<0.01). Muscle thickness and pennation angle of tibialis anterior in Korean young adults were greater than in Hanoi young adults (p<0.01). In addition, the muscle thickness and pennation angle of the medial part of gastrocnemius muscle were greater in Korean young adults than in Hanoi young adults (p<0.01). In addition, in the results for gender, men had larger muscle architectures than women in both groups (p<0.01). Conclusion: This study, using RUSI, showed significant difference in muscle architectures of lower extremity in a diverse group of young adults RUSI.