• Steel and Composite Structures
• /
• 제19권1호
• /
• pp.153-171
• /
• 2015

Twelve large-scale composite deck slabs were instrumented and tested in a cantilever diaphragm configuration to assess the effect of fibers and welded wire mesh (WWM) on the in-plane shear capacity of composite deck slabs. The slabs were constructed with reentrant decking profile and reinforced with different types and dosages of secondary reinforcements: Conventional welded wire mesh (A142 and A98); synthetic macro-fibers (dosages of $3kg/m^3$ and $5.3kg/m^3$); and hooked-end steel fibers with a dosage of $15kg/m^3$. The deck orientation relative to the main beam (strong and weak) was also considered in this study. Fibers and WWM were found efficient in distributing the applied load to the whole matrix, inducing multiple cracking, thereby enhancing the strength and ductility of composite deck slabs. The test results indicate that fibers increased the slab's ultimate in-plane shear capacity by up to 29% and 50% in the strong and weak directions, respectively. WWM increased the ultimate in-plane shear capacity by up to 19% in the strong direction and 9% in the weak direction. The results suggest that discrete fibers can provide comparable diaphragm behavior as that with the conventional WWM.

• 대한가정학회지
• /
• 제36권5호
• /
• pp.125-135
• /
• 1998

The purpose of this study is to investigate the overall levels of the middle-aged employed men's attitudes toward retirement and plans for post-retirement life, and to explore the relative effects of personal, family, and job characteristics on retirement attitude and the level of retirement plan. The data were collected from the 438 middle-aged (ranging from 41 to 50) employed men through the structured questionnaires. The data were analyzed using frequency, percentile, average, standard deviation, and multiple regression analysis. The results of the data analysis show that most of the respondents had neither positive nor negative attitude toward retirement and the level of planning for post-retirement life was slightly higher than average score on the scale. Next, the positive attitudes of middle-aged employed men toward retirement were observed from those who have higher education, larger household income, higher job security and lower job stress respondents who hold professional, administrative, or official jobs were more positive toward retirement than those who hold professional, administrative, or official jobs were more positive toward retirement than those who hold manufacturing or sales job. A well-planned post-retirement life was found among those who have better health, higher job satisfaction, job security and job orientation. Job characteristic variables such as job security and job satisfaction showed stronger impact than personal or family ones on the attitude toward retirement and the level of retirement planning. Household income and health also had significant effects.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2000년도 춘계학술발표대회 논문집
• /
• pp.93-96
• /
• 2000

The theory of non-prismatic folded plate structures was reported by the senior author in 1965 and 1966. Fiber reinforced composite materials are strong in tension. The structural element for such tension force is very thin and weak against bending because of small bending stiffnesses. Naturally, the box type section is considered as the optimum structural configuration because of its high bending stiffnesses. Such structures can be effectively analyzed by the folded plate theory with relative ease. The "hollow" bending member with uniform cross-section can be treated as prismatic folded plates which is a special case of the non-prismatic folded plates. Tn this paper, the result of analysis of a folded plates with one box type uniform cross-section is presented. Each plate is made of composite laminates with fiber orientation of [ABBCAAB]$_r$, with A=-B=$45^{\circ}$, and C=$90^{\circ}$. The influence of the span to depth ratio is also studied. When this ratio is 5, the difference between the results of folded plate theory and beam theory is 1.66%. is 1.66%.

• 대한토목학회논문집
• /
• 제13권1호
• /
• pp.65-74
• /
• 1993

중립축에 대하여 대칭인 보강된 적층평판의 좌굴하중을 극대화 하는 최적설계를 시도하였다. 전체 평판의 무게가 일정한 가운데 적층평판을 이루는 각기 판의 두께와 보강재의 단면을 이루는 두께와 높이를 설계변수로 취하였다. 유한요소법을 이용하여 평판의 좌굴하중이 계산되었으며 최적설계는 IMSL program routine을 사용하였다. 최적설계시 나타나는 optimality condition이 고도의 비선형 연립방정식이 되므로 이경우 여러개의 국부 최적점이 발견되었다. 보강재와 평판의 각층에서의 보강섬유의 방향을 달리하며 각자의 효율성을 연구 조사하였으며 이중($0^{\circ}Beam/0^{\circ}/90^{\circ}$)s인 경우에 사장 우수한 설계를 할수 있는것으로 나타났다.

• Clinics in Shoulder and Elbow
• /
• 제17권4호
• /
• pp.190-193
• /
• 2014

Recurrent posterior shoulder instability is a debilitating condition that is relatively uncommon, but its diagnosis in young adults is increasing in frequency. Several predisposing factors for this condition have been identified, such as the presence of an abnormal joint surface orientation, an osteochondral fracture of the humeral head or glenoid cavity, and a postero-inferior capsuloligamentary deficit, but their relative importance remains poorly understood. Whilst, conservative treatment is effective in cases of hyperlaxity or in the absence of bone abnormality, failure of conservative treatment means that open or arthroscopic surgery is required. In general, soft-tissue reconstructions are carried out in cases of capsulolabral lesions in which bone anatomy is normal, whereas bone grafts have been required in cases where posterior bony Bankart lesions, glenoid defects, or posterior glenoid dysplasia are present. However, a consensus on the exact management of posterior shoulder instability is yet to be reached, and published studies are few with weak evidence. In our study, we report the reconstruction of the glenoid using iliac bone graft in a patient suffering recurrent posterior shoulder instability with severe glenoid bone defect.

• 한국잠사곤충학회지
• /
• 제39권2호
• /
• pp.186-196
• /
• 1997

The IR crystallinity index of Calcium nitrate treated silk fiber decreased proportionally to the concentration of calcium nitrate. A partial change of conformation was observed in the concentration of over 46.4-47.6% changing from $\beta$-sheet or to random coil in the crystalline region. This is in coincidence with the result of crystallinity index, which was started to be reduced in the concentration range of 46.4-47.6%. A same trend was observed for the X-ray order factor, birefringence, degree of orientation and surface structure. These structural parameters were remarkably changed on the treatment of silk fibers with concentration of 46.4-17, 6% calcium nitrate. Therefore, it seems that there exists a critical concentration of calcium nitrate in affection the structure and morphology of silk fibers. According to the examination of surface morphology, the fine stripe was observed in the direction of fiber axis at 46.4% concentration. However, the treated concentration was exceeded by 47.6%, the cracks were appeared severely on the fiber surface in the transverse direction as well as fiber axis direction. This result might be related to the tensile properties, specially a tenacity of silk fibers. As a result of quantitative analysis of a dilute acid hydrolysis, three different regions, which are known as a amorphous, semi-crystalline and crystalline region, could be obtained. The hydrolysis rate curves were different with various concentrations of treatment and the relative contents of each region could be calculated.

• 한국전기전자재료학회논문지
• /
• 제25권2호
• /
• pp.121-124
• /
• 2012

The characteristics of Ga-doped zinc oxide (GZO) thin films deposited at different deposition temperatures (TS~250 to $550^{\circ}C$) on 4H-SiC have been investigated. Structural and electrical properties of GZO thin film on n-type 4H-SiC(0001) were investigated by using x-ray diffraction(XRD), atomic force microscopy(AFM), Hall effect measurement, barrier height from I-V curve and Auger electron spectroscopy(AES). XRD $2\theta$ scan shows GZO thin film has preferential orientation with c-axis perpendicular to SiC substrate surface. The lowest resistivity ($\sim1.9{\times}10^{-4}{\Omega}cm$) was observed for the GZO thin film deposited at $400^{\circ}C$. As deposition temperature increases, barrier height between GZO and SiC was increased. Whereas, resistivity of GZO thin films as well as barrier height between GZO and SiC were increased after annealing process in air atmosphere. It has been found that the c-axis oriented crystalline quality as well as the relative amount of activated Ga3+ ions and oxygen vacancy may affect the electrical properties of GZO films on SiC.

• International Journal of Aeronautical and Space Sciences
• /
• 제15권1호
• /
• pp.82-90
• /
• 2014

In this paper, the effect of Lorentz force on the stability of attitude orientation of a charged spacecraft moving in an elliptic orbit in the geomagnetic field is considered. Euler equations are used to derive the equations of attitude motion of a charged spacecraft. The equilibrium positions and its stability are investigated separately in the pitch, roll and yaw directions. In each direction, we use the Lorentz force to identify an attitude stabilization parameter. The analytical methods confirm that we can use the Lorentz force as a stabilization method. The charge-to-mass ratio is the main key of control, in addition to the components of the radius vector of the charged center of the spacecraft, relative to the center of mass of the spacecraft. The numerical results determine stable and unstable equilibrium positions. Therefore, in order to generate optimum charge, which may stabilize the attitude motion of a spacecraft, the amount of charge on the surface of spacecraft will need to be monitored for passive control.

• 한국농촌건축학회논문집
• /
• 제13권2호
• /
• pp.39-46
• /
• 2011

The agricultural population, the farming, the agriculture of our country has been decreased more rapidly than those of other countries. Also, the changing speed of the rural village in Korea has shown a similar trend. By considering the urbanization process and migration state caused by the economic growth and the increasing level of relative poverty in comparison with the urban area, it has been necessary to go through the impoverishment and slum-orientation of the rural area. In our country, the rural village became old age. So, the collapse is predicted to a population shortage if such trend is continued in the village society. according to investigate, Many urban peoples have opinion that migrates to a farm village. but those not migrate to rural community. The mainly reason is low life environment. therefore it is need the plan that the urban people migrates to a rural village, and must have the plan to be engaged in the agriculture. lt was the rural-fishing New Town development project that started in 2009 for 30~40 years's urban people. This study is about characteristic and improvement of Rural-Fishing New Town development project.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.610-615
• /
• 2005

Visual servoing is the fusion of results from many elemental areas including high-speed image processing, kinematics, dynamics, control theory, and real-time computing. It has much in common with research into active vision and structure from motion, but is quite different from the often described use of vision in hierarchical task-level robot control systems. We present a new approach to visual feedback control using image-based visual servoing with the stereo vision in this paper. In order to control the position and orientation of a robot with respect to an object, a new technique is proposed using a binocular stereo vision. The stereo vision enables us to calculate an exact image Jacobian not only at around a desired location but also at the other locations. The suggested technique can guide a robot manipulator to the desired location without giving such priori knowledge as the relative distance to the desired location or the model of an object even if the initial positioning error is large. This paper describes a model of stereo vision and how to generate feedback commands. The performance of the proposed visual servoing system is illustrated by the simulation and experimental results and compared with the case of conventional method for dual-arm robot made in Samsung Electronics Co., Ltd.