• Advances in materials Research
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• 제12권1호
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• pp.15-29
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• 2023

In this paper, fracture analysis of a continuously inhomogeneous arch structure with two longitudinal cracks is developed in terms of the time-dependent strain energy release rate. The arch under consideration exhibits non-linear creep behavior. The cross-section of the arch is a rectangle. The material is continuously inhomogeneous along the thickness of the cross-section. The arch is loaded by two bending moments applied at its end sections. The mechanical behavior of the material is described by using a non-linear stress-strain-time relationship. The two longitudinal cracks are located symmetrically with respect to the mid-span of the arch. Due to the symmetry, only half of the arch is considered. Time-dependent solutions to strain energy release rate are obtained by analyzing the balance of the energy. For verification, time-dependent solutions to the strain energy release rate are derived also by considering the time-dependent complementary strain energy. The evolution of the strain energy release rate with the time is analyzed. The effects of material inhomogeneity, locations of the two cracks along the thickness of the arch and the magnitude of the external loading on the time-dependent strain energy release rate are evaluated.

• Geomechanics and Engineering
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• 제25권2호
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• pp.111-121
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• 2021

Large deformation and rapid pressure propagation take place inside the rock mass under the dynamic loads caused by the explosives, on quarry faces in order to extract aggregate material. The complexity of the science of rock blasting is due to a number of factors that affect the phenomenon. However, blasting engineering computations could be facilitated by innovative software algorithms in order to determine the results of the violent explosion, since field experiments are particularly difficult to be conducted. The present research focuses on the design of a Finite Element Analysis (FEA) code, for investigating in detail the behavior of limestone under the blasting effect of Ammonium Nitrate & Fuel Oil (ANFO). Specifically, the manuscript presents the FEA models and the relevant transient analysis results, simulating the blasting process for three types of limestone, ranging from poor to very good quality. The Finite Element code was developed by applying the Jones-Wilkins-Lee (JWL) equation of state to describe the thermodynamic state of ANFO and the pressure dependent Drucker-Prager failure criterion to define the limestone plasticity behavior, under blasting induced, high rate stress. A progressive damage model was also used in order to define the stiffness degradation and destruction of the material. This paper performs a comparative analysis and quantifies the phenomena regarding pressure, stress distribution and energy balance, for three types of limestone. The ultimate goal of this research is to provide an answer for a number of scientific questions, considering various phenomena taking place during the explosion event, using advanced computational tools.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
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• pp.137-140
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• 2002

EM(ElectroMagnetic) pump is used for the purpose of transporting liquid sodium coolant with electrical conductivity in the LMR(Liquid Metal Reactor). In the present study, computer program for the pilot annular linear EM pump has been developed for the maximum flowrate with 200 l/min and maximum developing pressure with 3 bar. Firstly, Balance equation is induced by the equivalent circuit method which is commonly employed to analyze linear induction machines and the calculation of the hydraulic pressure drop. Then, design equation is converted to the computer program and optimum pump variables are determined by this code. The code is verified by the comparative analysis with the characteristic of the commercialized pump.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.1002-1006
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• 2004

The studies on OLED(Organic Light-Emitting Diode) materials and structures have been researched in other to improve luminescence efficiency of OLED. Electrons and holes are injected into the devices, transported across the layer and recombine to form excitons, their profiles are sensitive to mobility velocity of electrons and holes. A suggested means of improving the efficiency of LEDs would be to balance the injection of electrons and holes into light emission layer of the device. In this paper, we demonstrate the difference of velocity between hole and electron by experiments, and compare with a data of simulation and experiment changing hole carrier transport layer thickness, so we get the optimal we improve luminescence efficiency. We improve understanding of the various luminescence efficiency through experiments and numerical analysis of luminescence efficiency in the hole carrier transport layer's thicknes.

• 한국자동차공학회논문집
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• 제5권3호
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• pp.117-127
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• 1997

To maintain the reasonable temperature in the engine is very important to keep the steady combustion state of engine and to prevent increasing of lubricant consump- tion, deteriorating of lubricant, shortening of the life time of engine and decreasing of material strength. The method of energy balance for devided elements of radiator is considered to analyse the performance of radiator. Th data of engine test and vehicle cooling tunnel test are applied to program for calculation of radiator outlet temperature, and this result is compared with outlet temperature of vehicle cooling tunnel test. As a result, the radiator outlet temperature by numerical analysis agrees well with that by experiment. It is concluded that this simulation program is available in developing the cooling system for a new car.

• Coupled systems mechanics
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• 제11권6호
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• pp.543-556
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• 2022

Delamination of multilayered inhomogeneous beam that exhibits non-linear relaxation behavior is analyzed in the present paper. The layers are inhomogeneous in the thickness direction. The dealamination crack is located symmetrically with respect to the mid-span. The relaxation is treated by applying a non-linear stress-straintime constitutive relation. The material properties which are involved in the constitutive relation are distributed continuously along the thickness direction of the layer. The delamination is analyzed by applying the J-integral approach. A time-dependent solution to the J-integral that accounts for the non-linear relaxation behavior is derived. The delamination is studied also in terms of the time-dependent strain energy release rate. The balance of the energy is analyzed in order to obtain a non-linear time-dependent solution to the strain energy release rate. The fact that the strain energy release rate is identical with the J-integral value proves the correctness of the non-linear solutions derived in the present paper. The variation of the J-integral value with time due to the non-linear relaxation behavior is evaluated by applying the solution derived.

• Coupled systems mechanics
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• 제3권1호
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• pp.53-71
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• 2014

Accurate prognoses of the durability of concrete structures require a detailed description of the continuously running aging processes and a consideration of the complete load history. Therefore, in the framework of continuous porous media mechanics a model is developed, which allows a detailed analysis of the most important aging processes of concrete as well as a flexible coupling of different processes. An overview of the prediction model and the balance equations is given. The material dependent model equations, the consequences of coupling different processes and the solution scheme are discussed. In two case studies the aging of concrete due to hydration and chloride penetration are presented, which illustrate the capabilities and the characteristics of the developed model.

• 한국콘텐츠학회논문지
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• 제16권8호
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• pp.693-705
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• 2016

본 연구는 근로자의 일과 삶의 균형을 지원하는 조직문화 척도(일과 삶의 균형 조직문화 척도)를 개발하고, 타당도를 검증하기 위해 수행되었다. 이를 위해 국내외 일과 삶의 균형과 조직문화 관련 연구결과 및 측정도구를 고찰하였고, 이를 토대로 일과 삶의 균형 조직문화 척도를 구성하는 요인들을 이론적으로 추출하여 예비문항을 구성하였다. 30대-50대 기혼 직장인 773명을 대상으로 설문조사를 실시하였다. 그 결과, 탐색적 확인적 요인분석을 통해 5개의 요인을 최종적으로 추출하였다: WLB 기업의지, WLB 상사배려, 동료의사소통, 동료지원, WLB 제도사용 용이성. 다음으로, 일과 삶의 균형 조직문화 척도의 타당도 검증을 위해 수렴타당도, 변별타당도, 준거관련 타당도(동시적 타당도, 예언타당도) 등을 확인하였다. 그 결과, 일과 삶의 균형 조직문화척도가 유사 조직문화 척도들 그리고 일과 삶의 균형, 삶만족도, 직무만족, 조직몰입, 이직의도, 경력단절의도와 유의한 상관관계를 보였다. 본 연구를 통해 일과 삶의 균형 조직문화를 측정하는 타당도있는 다차원 척도를 개발할 수 있었으며, 이는 향후 일과 삶의 균형과 조직문화에 관한 연구의 질을 향상시키는데 기여할 것으로 기대된다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 2부
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• pp.105-109
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• 2011

This study is concerned with the development of the SL inorganic floor covering. First, volatile organic compounds, inorganic test profile on the SL through the flooring is environment-friendly inorganic noncombustible floor finishes the event of fire toxic gases (such as volatile organic compounds) emissions have been identified as not at all. Second, SL-breathable material, the concrete floor to prevent aging, long life, which are three levels of noise, shock-absorbing function was decreased. Third, SL economic analysis of mineral flooring terrazzo tile floors compared with the normal material. On a terrazzo tile cost 13,500 won ~ 24,500 won, but It have found that, in terms of labor SL 36,899 won ~ 38,899 won flooring mineral balance. Occurs in the total amount when compared with terrazzo tile floors and 25,399 won 3T, 5T and economical analysis concludes that the original 12,399 won.

• 한국전기전자재료학회논문지
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• 제35권4호
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• pp.372-376
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• 2022

Since the ZnO varistor is a semiconductor device, the internal thermal distribution during the varistor operation is recognized as an important factor in the performance and deterioration of the varistor. For an optimal varistor structure design, the thermal runaway phenomenon during the varistor operation was interpreted using the Comsol 5.2 analysis program by a finite element analysis. The maximum temperature of the center measured in the cross section of the ZnO varistor was confirmed to increase as the temperature moved from the lower electrode to the center towards the upper electrode up to 572.6 K. The electrodes are thinned so that the influence of the Schottky barrier is not great. The heat gradient balance is determined to be improved when the electrode of the hybrid form is introduced. The thickness, density, pore distribution, impurity uniformity, and particle size of the ZnO varistor are required, and it is determined that the pyrolysis gradient will be improved regardless of the electrode thickness. When these results are applied to design the ZnO varistor, the optimal structure of the ZnO varistor can be obtained.