• Structural Engineering and Mechanics
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• 제62권6호
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• pp.719-724
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• 2017

We consider an elastic isotropic plate reinforced by stringers and weakened by a periodic system of rectilinear slots of variable width. The variable width of the slots is comparable with elastic deformations. We study the case when the slots faces get in contact at some area. Determination of parameters characterizing the partial closure of variable width slots is reduced to the solution of a singular integral equation. The action of the stringers is replaced with unknown equivalent concentrated forces at the points of their connection with the plate. The contact stresses and contact zone sizes are found from the solution of the singular integral equation.

• Structural Engineering and Mechanics
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• 제76권2호
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• pp.153-162
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• 2020

Aiming at the mechanical and structural characteristics of the contact zone composite rock, the shear tests and numerical studies were carried out. The effects of the differences in mechanical properties of different materials and the normal stress on shear properties of contact zone composite samples were analyzed from a macro-meso level. The results show that the composite samples have high shear strength, and the interface of different materials has strong adhesion. The differences in mechanical properties of materials weakens the shear strength and increase the shear brittleness of the sample, while normal stress will inhibit these effect. Under low/high normal stress, the sample show two failure modes, at the meso-damage level: elastic-shearing-frictional sliding and elastic-extrusion wear. This is mainly controlled by the contact and friction state of the material after damage. The secondary failure of undulating structure under normal-shear stress is the nature of extrusion wear, which is positively correlated to the normal stress and the degree of difference in mechanical properties of different materials. The increase of the mechanical difference of the sample will enhance the shear brittleness under lower normal stress and the shear interaction under higher normal stress.

• 한국세라믹학회지
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• 제53권4호
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• pp.411-416
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• 2016

Benzothienobenzothiophene ($C_8-BTBT$) is a soluble organic small molecule material with high crystallinity resulting from its strong self-organizing properties. In addition, the high mobility and easy fabrication of $C_8-BTBT$ make it very attractive in terms of organic thin-film transistors. In this work, we made $C_8-BTBT$ thin films by using the zone-casting method; we also used an organic solvent to treat the devices with solvent vapor annealing to improve the electrical properties. As a result, we confirmed improved mobility, threshold voltage, and subthreshold swing after solvent vapor annealing. To prove the effect of solvent vapor annealing, we used the simultaneous extraction model to extract the contact resistance from the current-voltage curve. We confirmed that the electrical properties improved with decreasing contact resistance.

• 대한기계학회논문집A
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• 제27권10호
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• pp.1703-1711
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• 2003

An elastic-plastic finite element analysis is performed to investigate detailed closure behaviour of fatigue cracks in residual stress fields and the numerical results are compared with experimental results. The finite element analysis performed under plane stress using contact elements can predict fatigue crack closure behaviour. The mesh of constant element size along crack surface can not predict the opening level of fatigue crack. Specially, the mesh of element sizes depending upon the reversed plastic zone size included the effect of crack opening point can precisely predict the opening level. By using the concept of the mesh of element sizes depending upon the reversed plastic zone size included the effect of crack opening point, the opening level of fatigue crack can be determined very well.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.427-432
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• 2003

In contact-type multiview 3 dimensional imaging systems, the optimum design parameters are not easily found because of difficulty in determining the size of viewing zone. Two factors related with the viewing zone, such as different view image patching and the widths of the viewing regions are discussed to explain the difficulty.

• E2M - 전기 전자와 첨단 소재
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• 제10권9호
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• pp.895-900
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• 1997

A Quench in cable-in-conduit (CIC) conductors is often initiated by a disturbance such as strand motion that generates a highly localized normal zone in a strand or a few strands of the CIC conductors. The localized normal zone causes current and heat transfer between a disturbed strand and neighboring strands. Electrical and thermal contact characteristics between strands thus have an effect on the transient stability of the CIC conductors. In this paper the effect of contact characteristics between strands on the CIC conductor stability is presented based on the measured heat transfer characteristics of supercritical helium (SHe) for the local heating. The quench and recovery processes of the strands for the abrupt and highly localized disturbance are analyzed at the boundary between quench and recovery.

• Structural Engineering and Mechanics
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• 제83권3호
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• pp.341-351
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• 2022

During bolted flange assembly, the contact stiffness of some areas of the joint surface may be low due to the elastic interaction. In order to improve the contact stiffness at the lowest position of bolted flange, the correlation model between the initial bolt pre-tightening force and the contact stiffness of bolted flange is established in this paper. According to the stress distribution model of a single bolt, an assumption of uniform local contact stiffness of bolted flange is made. Moreover, the joint surface is divided into the compressive stress region and the elastic interaction region. Based on the fractal contact theory, the relationship model of contact stiffness and contact force of the joint surface is proposed. Considering the elastic interaction coefficient method, the correlation model of the initial bolt pre-tightening force and the contact stiffness of bolted flange is established. This model can be employed to reverse determine the tightening strategy of the bolt group according to working conditions. As a result, this provides a new idea for the digital design of tightening strategy of bolt group for contact stiffness of bolted flange. The tightening strategy of the bolted flange is optimized by using the correlation model of initial bolt pre-tightening force and the contact stiffness of bolted flange. After optimization, the average contact stiffness of the joint surface increased by 5%, and the minimum contact stiffness increased by 6%.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.499-502
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• 2005

A process map has been developed, which can identify the process conditions for weak mechanical bonding at the contact surface during the direct extrusion of a Cu-Ti bimetal bar. Bonding mechanism between Cu and Ti was assumed as a cold pressure welding. Then, the plastic deformation at the contact zone causes mechanical bonding and a new bonding criterion for pressure welding was developed as a function of the principal stretch ratio and normal pressure at the contact surface by analyzing micro local extrusion at the contact zone. Finite element analyses for extrusion of Cu-Ti bimetal bars were performed for various process conditions. The deformation history at the contact surface was traced and the proposed new bonding criterion was applied to predict whether the mechanical bonding at the Cu-Ti contact surface happens. Finally, a process map for the extrusion of Cu-Ti bimetal bar is suggested.

• 한국지반환경공학회 논문집
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• 제8권6호
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• pp.85-95
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• 2007

탄질 셰일 파쇄대의 경우, 물리탐사의 사전조사방법으로 그 여부를 파악하기 어렵고 또한, 용수등에 노출이 안되는 경우 탄질 셰일층 강도 자체는 양호한 특성이 있다. 그러나 이러한 탄질 셰일층의 경우 용수에 접하거나 대기에 노출되는 경우 단기간내에 강도가 급격히 저하되거나 풍화가 급속히 진전되는 매우 취약한 특성이 있다. 따라서 사전 예측하기가 어렵고 붕락발생시 급작스럽게 발생하는 경우가 대부분이다. 강도감소 측면에서는 용수와 접할시, 탄층 세일 파쇄대층에 대한 점하중 강도 시험결과 12시간 경과후 강도가 56%감소하였다. 또한 본 논문에서는 탄질 셰일 파쇄구간에 대한 표준 보강단면을 제시하였다.

• 유통과학연구
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• 제11권8호
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• pp.25-30
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• 2013

Purpose - Foodservices have grown to over 60% of the franchise industry. However, despite reaching this high level, the foodservice franchise industry is experiencing severe ups and downs. While factors such as expansion by franchises and the entry of large multinational firms are causing this imbalance, the more serious problem faced by franchisees is the lack of know-how and correct operating procedures. Franchise headquarters should advise franchisees on important matters such as food ingredients, interior design, tableware, and fixtures. However, even though franchise headquarters have the ability to impart such management know-how, this is often a neglected area. Research design, data and methodology - This study was conducted in an industrial environment to present suitable competitive alternatives for foodservice franchises. Empirical analysis was conducted using a sample of 232 people with experience in targeting customers. The main purpose of this study is not to identify and analyze the factors affecting customer satisfaction. Customers of the Food Service Industry to invite contacts until departure for the service flow by identifying the expectations and allow this area by analyzing the resulting measures to enhance the competitiveness has presented. Results - Actual results contact factors affecting the quality of service on customer satisfaction was a significant influence. However, the end of this analysis, the actual customer satisfaction directly affects the quality of service that is only important factor can commit mistakes. Relatively large impact on customer satisfaction, which is relatively independent of the quality factor should be a review of zone of tolerance. In this study, eating phase relative to contact the service customer satisfaction was the most influential. The results, however, zone of tolerance for an area in the waiting and ordering dissatisfaction factors are appearing. And in the course of these services outside the zone of tolerance area is unsatisfactory evaluation is being done. Conclusions - After all, Foodservice, the contact service management for zone of tolerance the top priority should be can be seen. Foodservice contact first in the case of service quality factors caused by the continuous flow of services, so this step-by-step identification needs to be clearer. This, of course, to distinguish between the actual per unit of activity appears to be more difficult to follow, for it seems to need a lot of future complementary. Next is the assessment of customer service quality. Customers remember the experience for the services of a real contact through the assessment and service evaluation clearly emerge as the expected level can be difficult. However, this situation is controlled by the test method cannot be avoided unless there is no limit to the number of leave. Despite these limitations, the next step to contact a service evaluation and analysis have to continue to refine and thereby franchisees for the operation of the store in terms of practical know-how required to provide to the office believe.