• 대한물리치료과학회지
• /
• 제30권3호
• /
• pp.41-48
• /
• 2023

Background: This study examined the effects of the bridge exercise with trunk rotation on the thickness of body trunk muscles, including external oblique, internal oblique, and transverse abdominis in healthy male adults. Design: Randomized controlled trial Methods: Twenty-four men were evenly divided into a trunk rotation bridge exercise group and a basic bridge exercise group by drawing lots. The two groups performed the respective exercise for thirty minutes, three times a week for six weeks. repeated measure analysis of variance (ANOVA) was used after distinguishing between three different time points before the experiment, three weeks after the experiment, and six weeks after the experiment. The significance level was set at 0.05. In case an interaction between time and group existed, the paired t-test was used to examine the within-group difference. The independent-sample t-test was used to check the between-group difference. The significance level was set at 0.05. Results: All the men showed a significant change over time in their external oblique, internal oblique, and transverse abdominis muscles. An interaction between time and group was also found (p<0.05). Conclusion: The bridge exercise with trunk rotation causes a meaningful difference in the thickness of external oblique, internal oblique, and transverse abdominis muscles. Therefore, this study proposes the use of this exercise for lower-back stabilization in future research and clinical settings.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 하계학술대회 논문집
• /
• pp.423-426
• /
• 2001

Recently we have reported that the meander-patterned amorphous FeCoSiB films exhibit large change in their high frequency impedance by applying a strain, suggesting that the films are very attractive for making of a highly sensitive strain sensor elements. In this study, the effect of anisotropy on a change in the impedance of sputtered amorphous film patterns was investigated in the frequency range from 1MHz to 1GHz. As a function of applied strains, the high frequency impedance was extremely changed in the case of film patterns with transverse anisotropy due to excellent magnetomechanical coupling properties. As a summary, the maximum figure of merit f has measured about 2600 in the case of transverse anisotropy, and about 500 in the case of longitudinal anisotropy at 500 MHz. These values of F are approximately more than 1000 times higher than that of a conventional metal strain gauge (F 2) and more than 10 times higher than that of a semiconductor gauge (F 200).

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.147-149
• /
• 2005

On this study, we optimized maximizing thrust force of weight ratio and minimizing detent force of weight ratio at the TFLM(Transverse Flux Linear Motor) using design of experiments by the table of orthogonal array, characteristic function and analysis of means(ANOM), For two functions or more, the effectiveness of design change can be evaluated in accordance with change in design parameters. Also, The stator and mover weight of TFLM is reduced by up to 20 percent while its thrust force of weight ratio and detent force of weight improved. From now on, we are going to apply the required technique to design various uses and shares of the TFLM.

• 한국음향학회지
• /
• 제31권8호
• /
• pp.514-522
• /
• 2012

횡진동 모드 압전진동자의 우주-항공산업에의 적극적인 활용을 위하여 우주환경을 모사한 열진공 챔버를 사용하여 $-100^{\circ}C{\sim}90^{\circ}C$의 범위에서 PZT-5계열의 압전세라믹 진동자의 온도변화에 따른 특성변화를 조사하였다. 그 결과 공진 및 반공진주파수는 상온일 때를 중심으로 온도의 변화에 따라 증가하였고 유전상수의 경우 주어진 온도 범위에서 2500~7500의 범위에서 선형적으로 증가하였다. 기계적 손실은 0.08~0.03의 범위에서 선형적으로 감소하는 경향을 보였다. 이들에 대한 회귀분석을 통하여 1차원 및 2차원 회귀함수를 이용하여 압전진동자의 각 특성에 대한 온도의존함수들을 도출하였다. 이들 함수를 적용하여 구한 횡모드 압전 진동자의 입력어드미턴스의 계산결과는 측정결과와 좋은 일치를 보이고 있었으며 우주환경에서의 온도에 따른 특성변화 예측에 유효함을 확인할 수 있었다.

• 대한물리치료과학회지
• /
• 제29권1호
• /
• pp.64-72
• /
• 2022

Background: The purpose of this study is to investigate the effect of wall squat exercise according to the difference in the support surface on the thickness change of external oblique, internal oblique and transverse abdominalis of the trunk muscles and the change in distance of center of pressure when the eyes are opened and closed. Design: Randomized controlled trial. Methods: The subjects were 26 healthy adults, 18 males and 8 females. The composition of each group using the single-blind method was 13 people in the unstable side wall squat exercise group and 13 people in the stable side wall squat exercise group. Experimental measurements were divided into before, 3 weeks, and 6 weeks after the experiment, and changes in muscle thickness and balance were confirmed. Muscle thickness was measured using ultrasinic, and static balance change was measured using Bio-rescue. Results: There were significant differences in the thickness changes of external oblique, internal oblique and transverse abdominalis according to the wall squat exercise method by period and in the interaction between the period and the group (p<0.05). As a result of the post-hoc analysis, there was a significant difference in the change between the two groups in external oblique muscle after 6 weeks. And there was a significant difference in the distance of the pressure center between eyes open and closed eyes (p<0.05). Conclusion: In terms of instability, wall squat exercise was positive for changes in trunk muscle thickness. It suggests the possibility of using it for trunk muscle strengthening training in the future.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회B
• /
• pp.2638-2641
• /
• 2007

The magnetohydrodynamic(MHD) pressure drop along a liquid sodium flow was measured in a rectangular duct under a transverse magnetic field. The test section was made of a 3 mm thick stainless steel SUS304 with a $74{\times}5mm^2$ rectangular flow channel. The range of experimental parameters was roughly B=0${\sim}$0.18T and U=0${\sim}$0.9m/s at around $200^{\circ}C$. The differential pressure was measured by a diaphragm seal-type pressure transmitter filled with a high temperature silicon oil within 0.1MPa. The experimental results show a similar pressure drop with the theoretical estimation according to a change of the flow velocity and the magnetic field.

• Structural Engineering and Mechanics
• /
• 제14권4호
• /
• pp.401-416
• /
• 2002

This paper presents a domain decomposition method for buckling analysis of rectangular Kirchhoff plates subjected to uniaxial inplane load and with mixed edge support conditions. A plate is decomposed into two rectangular subdomains along the change of the discontinuous support conditions. The automated Ritz method is employed to derive the governing eigenvalue equation for the plate system. Compatibility conditions are imposed for transverse displacement and slope along the interface of the two subdomains by modifying the Ritz trial functions. The resulting Ritz function ensures that the transverse displacement and slope are continuous along the entire interface of the two subdomains. The validity and accuracy of the proposed method are verified with convergence and comparison studies. Buckling results are presented for several selected rectangular plates with various combination of mixed edge support conditions.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2001년도 추계학술발표대회 논문집
• /
• pp.191-194
• /
• 2001

A partially coupled thermo-piezoelectric-mechanical triangular finite element model of composite laminates with surface bonded piezoelectric actuators, subjected to externally applied mechanical load, temperature change load, electric field load is developed. The governing differential equations are obtained by applying the principle of free energy and variational techniques. A higher order zigzag theory displacement field is employed to accurately capture the transverse shear and normal effects in laminated composite plates of arbitrary thickness. Nonconforming shape functions by Specht are employed in the transverse displacement variables. Numerical examples demonstrate the accuracy and efficiency of the proposed triangular plate element.

• 한국자동차공학회논문집
• /
• 제1권1호
• /
• pp.41-49
• /
• 1993

Piston slap is one of the major sources of noise in a 4-cycle diesel engine. Piston slap is not only one of major source mounted near the top and bottom of the piston thrust and antithrust skirts. Effects of engine speed, load and coolant temperature on piston motion were investigated. The measured piston motion showed 6 slapes per cycle resulting from the change of side force. Major piston slap timing was retarded as engine speeds became higher. The increase of engine load made large piston transverse movement toward thrust side of cylinder block. Piston transverse movement was due to reduced piston-liner clearance at higher coolant temperature.

• Steel and Composite Structures
• /
• 제2권5호
• /
• pp.355-378
• /
• 2002

Use of composite steel construction with precast hollow core slabs is now popular in the UK, but the present knowledge in shear capacity of the headed shear studs for this type of composite construction is very limited. Currently, all the information is based on the results obtained from experimental push-off tests. A finite element model to simulate the behaviour of headed stud shear connection in composite beam with precast hollow core slabs is described. The model is based on finite element method and takes into account the linear and non-linear behaviour of all the materials. The model has been validated against the test results, for which the accuracy of the model used is demonstrated. Parametric studies showing the effect of the change in transverse gap size, transverse reinforcement diameter and in-situ concrete strength on the shear connection capacity are presented.