• 한국전기전자재료학회논문지
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• 제15권12호
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• pp.1054-1059
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• 2002

A great deal of research has been done in the field of characterization for piezoelectric thin films after the first report on the measurement for the piezoelectric coefficient of thin films in 1990. The main idea of this research is to provide a distinctive solution for the measurement and standardization of both the longitudinal and the transverse piezoelectric d-coefficients, d33 and d31, of ferroelectric thin films. In general, to get these two coefficients of thin films, two different measuring systems are required. Here, we propose the improved method for the evaluation of these two coefficients with single equipment and with the relatively convenient procedure. The two-step loading process of applying the both positive and the negative pressure has been introduced to acquire the piezoelectric coefficients. These results have been calibrated for both the longitudinal and 4he transverse piezoelectric d-coefficients, d33 and 431, of thin films by comparison with the virtual standard created from FEM. In this experiments, we have obtained d33 of 331pC/N and 031 of -92.2pC/N for the PZT thin films.

• 한국전산구조공학회논문집
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• 제19권4호
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• pp.347-356
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• 2006

본 논문에서는 단면상의 화이버 요소를 사용하여 3차원 강구조물의 점진적인 소성화를 고려하는 실용적인 비선형 비탄성 해석방법을 개발하였다. 부재의 p-$\delta$, p-$\Delta$ 등의 기하비선형은 안정함수로 고려하였다. 잔류응력은 단면상에 있는 화이버 요소에 초기응력을 가하여 고려하였다. 각 하중 단계에서 탄성상태인 단면을 계산하여 축강성과 휨강성을 직접 결정함으로서 점진적인 소성화를 고려하였다. 각 화이버 요소의 응력 변화를 계산하여 변형률 반전효과를 고려하였다. 제안된 해석 방법은 3차원 강구조물의 실용적인 해석 및 설계에 유용하게 사용될 것이라 판단한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2772-2774
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• 2000

According to the development of marine transportation business and the modernization and over sizing of vessel transportation equipment. shipping equipment used in the terminal are getting more atomized and speedier. thus the efficiency of shipping and discharging depends upon the degree of practice of terminal operating manpower. It means that cultivation of experts in this field is essentially needed and it is becoming a serious problem to guarantee the training programs to provide high-class. high-skilled manpower. The best result can be expected when we use the real equipment for training purposes. but it will cause many difficulties such as budget problem. To overcome this situation. we developed the Virtual Container Crane Simulator(VCCS System) which enables the operator to learn the operation of the equipment as well as safety problems within a short time. VCCS system begins with establishing the direction of operation by setting the appropriate motions for each step. and then it instructs the basic operation. It enhances the driver's ability to cope with accidents during operation and completes and completes the mastery of operating techniques with The repetition of practice.

• 대한조선학회논문집
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• 제28권2호
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• pp.228-240
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• 1991

균열진전에 관한 많은 실험결과는 피로 균열진전 과정이 확률과정(stochastic process)임을 보여주고 있다. 따라서, 피로 균열진전에 관한 연구는 확률론적 기반에서 다루어져야 한다. 본 연구에서는 균열의 진전과정을 discrete Markov process로 가정하여, Bogdanoff가 제안한 Markov chain model(MCM)을 이용하여 구조물의 신뢰도를 평가할 수 있는 방법을 제시한다. 본 연구에서는 구조부재의 파괴형태로 누출, 소성붕괴 그리고 취성파괴를 취하였으며, 초기 균열크기의 변동성, 검사의 효과 등이 고려되었다. 또한, 불규칙 하중은 등가음력의 개념을 도입하여 처리하였다. 그리고, 구조물에의 계산례를 통하여 본 연구의 유용성을 보였다.

• 한국지진공학회논문집
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• 제21권5호
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• pp.205-213
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• 2017

The WUF-W moment connection is a pre-qualified connection that can be used for special moment frames specified in current seismic design specifications. Since the stress distribution near the connection varies according to access hole configuration, the cyclic performance of WUF-W connections is strongly affected by the access hole configurations. To evaluate the connection performance according to various access hole configurations, it is expensive to conduct experiments with many connection specimens. Instead, finite element analyses (FEA) can be performed. Throughout the FEA, stress and strain distribution in the connection can be monitored at each loading step. The purpose of this study is to construct nonlinear 3-dimensional FE models for accurately predicting the cyclic behavior of WUF-W connections. For predicting connection fracture using FEA, an appropriate response index detecting the incidence of connection rupture is proposed.

• Structural Engineering and Mechanics
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• 제23권5호
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• pp.455-468
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• 2006

Smart structural systems are defined as ones that demonstrate the ability to modify their characteristics and/or properties in order to respond favorably to unexpected severe loading conditions. The performance of such a task requires a set of additional components to be integrated within such systems. These components belong to three major categories, sensors, processors and actuators. It is wellknown that all structural systems entail some level of uncertainty, because of their extremely complex nature, lack of complete information, simplifications and modeling. Similarly, sensors, processors and actuators are expected to reflect a similar uncertain behavior. As it is imperative to be able to evaluate the impact of such components on the behavior of the system, it is as important to ensure, or at least evaluate, the reliability of such components. In this paper, a system model for reliability assessment of smart structural systems is outlined. The presented model is considered a necessary first step in the development of a reliability assessment algorithm for smart structural systems. The system model outlines the basic components of the system, in addition to, performance functions and inter-relations among individual components. A fault tree model is developed in order to aggregate the individual underlying component reliabilities into an overall system reliability measure. Identification of appropriate limit states for all underlying components are beyond the scope of this paper. However, it is the objective of this paper to set up the necessary framework for identifying such limit states. A sample model for a three-story single bay smart rigid frame, is developed in order to demonstrate the proposed framework.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권2호
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• pp.122-127
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• 2005

A size exclusion chromatography (SEC) process, in the presence of denaturant in the refolding buffer was developed to refold recombinant human $interferon-\gamma$ ($rhIFN-\gamma$) at a high concentration. The $rhlFN-\gamma$ was overexpressed in E. coli resulting in the formation of inactive inclusion bodies (IBs). The IBs were first solubilized in 8 M urea as the denaturant, and then the refolding process performed by decreasing the urea concentration on the SEC column to suppress protein aggregation. The effects of the urea concentration, protein loading mode and column height during the refolding step were investigated. The combination of the buffer-exchange effect of SEC and a moderate urea concentration in the refolding buffer resulted in an efficient route for producing correctly folded $rhIFN-\gamma$, with protein recovery of $67.1\%$ and specific activity up to $1.2\times10^7\;IU/mg$.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.447-448
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• 2007

Product development is consisting by trend that accommodate almost function digital cam in camera phone that can speak of Mobile appliance, and competition about number of elemental area of image sensor is consisting for market prior occupation between these. Propose in this research and small size camera phone self-focusing adjustment actuator that do city manufacture is similar with general storehouse pickup actuator drive way, but selected in cylindrical to reduce space that lens holder occupies because there is restriction loading of lens and space enemy. Target number of research established that execute drive displacement more than $600{\mu}m$ in 2.75V that is house voltage that is used in Mobile device that is general. Also, described about maximum transfer displacement characteristic, displacement response characteristic, hysteresis, response characteristic, smallest transfer step characteristic, actuator's drive characteristic that is manufactured to examination item of maximum consumption electric power by special quality estimation system that apply laser displacement sensor that produce itself to evaluate city manufactured actuator's special quality.

• 한국지하수토양환경학회지:지하수토양환경
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• 제10권4호
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• pp.13-17
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• 2005

암모늄의 질산화 반응, 질소산화물의 탈질 반응, 그리고 유기물의 산화반응을 고려한 SAT 모델링 시스템에 대해서, 현장조건의 변화에 따른 모델 결과를 비교하기 위해 6가지 모델 조건에 대한 가상의 수직 2차원상 모델 시뮬레이션을 하였다. 시뮬레이션 조건에서 수리전도도, 주입수 주입율, 지표 피복 여부, 그리고 운영 계획과 같은 4가지 영향 인자들이 고려되었다. 시뮬레이션 결과, 모든 조건에서 모델 개발 과정에서 고려한 반응 영향들이 잘 모사되었다.

• Water Engineering Research
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• 제4권1호
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• pp.19-30
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• 2003

TMDL development and implementation have great potential fur use in efforts to improve water quality management, but the TMDL approach still has several difficulties to overcome in terms of cost, time requirements, and suitable methodologies. A well-defined prioritization approach for identifying watersheds of concern among several tar-get locations that would benefit from TMDL development and implementation, based on a simple screening approach, could be a major step in solving some of these difficulties. Therefore, a web-based decision support system (DSS) was developed to help identify areas within watersheds that might be priority areas for TMDL development. The DSS includes a graphical user interface based on the HTML protocol, hydrological models, databases, and geographic information system (GIS) capabilities. The DSS has a hydrological model that can estimate non-point source pollution loading based on over 30 years of daily direct runoff using the curve number method and pollutant event mean concentration data. The DSS provides comprehensive output analysis tools using charts and tables, and also provides probability analysis and best management practice cost estimation. In conclusion, the DSS is a simple, affordable tool for the preliminary study of TMDL development via the Internet, and the DSS web site can also be used as an information web server for education related to TMDL.