• Title/Summary/Keyword: double scale model

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LES OF TURBULENT PREMIXED COMBUSTION FLAME AND LES APPLICATION FOR THE INDUSTRIAL COMBUSTOR DEVELOPMENT (난류 예혼합연소 화염의 LES 및 산업용 연소기 개발을 위한 LES 응용 해석 기술)

  • Park, Nam-Seob;Ryu, Jong-Hyuk
    • 한국전산유체공학회:학술대회논문집
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    • 2010.05a
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    • pp.437-441
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    • 2010
  • LES results of turbulent premixed combustion flows are introduced by using the dynamic sub-grid scale model based on G-equation describing the flame front propagation. The turbulent premixed combustion flows around bluff body and over backward facing step are analyzed to validate present formation. LES of swirling partially premixed combustion flame is also performed to conform the predictive capabilities of LES model and to prompt our understanding for the combustion flows over double cone swirl burner combustor by using CFD-ACE+ commercial code.

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Centrifuge Model Tests for the Slope Reinforcement Effect (사면 보강효과 확인을 위한 원심모형실험)

  • 박용원;김병일;박종호;홍성수
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.521-528
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    • 2002
  • This paper presents the results of centrifuge model tests on the reinforced slope by pressure grouting. Tests were performed to investigate the reinforcing effect of grouting. In the tests, slopes of scale factor 1/10 were used changing the space and number of reinforcing bar. Test results are as tile follows; 1. The reinforcing effect increase rapidly with reinforcement area ratio at low value of reinforcement area ratio. 2. At high reinforcement area ratio the increase ratio of reinforcing effect decrease. 3. At same reinforcement area ratio, the reinforcing effect of double reinforcing bar was larger than the single reinforcing bar due to arching effect.

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A probabilistic micromechanical framework for self-healing polymers containing microcapsules

  • D.W. Jin;Taegeon Kil;H.K. Lee
    • Smart Structures and Systems
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    • v.32 no.3
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    • pp.167-177
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    • 2023
  • A probabilistic micromechanical framework is proposed to quantify numerically the self-healing capabilities of polymers containing microcapsules. A two-step self-healing process is designed in this study: A probabilistic micromechanical framework based on the ensemble volume-averaging method is derived for the polymers, and a hitting probability model combined with a crack nucleation model is then utilized for encountering microcapsules and microcracks. Using this framework, a series of parametric investigations are performed to examine the influence of various model parameters (e.g., the volume fraction of microcapsules, microcapsule radius, radius ratio of microcracks to microcapsules, microcrack aspect ratio, and scale parameter) on the self-healing capabilities of the polymers. The proposed framework is also implemented into a finite element code to solve the self-healing behavior of tapered double cantilever beam specimens.

A Comparative Analysis on the Competitiveness of Korean and Japanese Fashion Industry by Applying Generalized Double Diamond Model

  • Son, Mi Young;Kenji, Yokoyama
    • Asia Marketing Journal
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    • v.15 no.1
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    • pp.57-81
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    • 2013
  • The purpose of this paper is to seek ways to improve the competitiveness of Korea's fashion industry by utilizing the source of competitiveness of Japan's fashion industry, which represents the world's leading countries in terms of fashion, so that Korea can better enter the global fashion market. The study shall first compare the competitiveness of the Japanese and Korean fashion industries by utilizing the generalized double diamond model; second, provide an understanding of what the Japanese fashion industry can offer to Korean fashion industry and companies - that is, understand what the Japanese fashion industry's competitive edge is; and third, study the kind of global competitiveness that Korea's fashion industry must achieve. To adopt a generalized double diamond model to compare the competitiveness of the Korean and Japanese fashion industries, we selected 31 sub-variables to act as determinants of the model. That is, we extracted 31sub-variables by doing research of literature to analyze national competitiveness of the fashion industries. To measure these 31 sub-variables, secondary data was gathered. We collected data related to each sub-variable from various sources of Korea and Japan. And to calculate the competitiveness index, we took three steps with reference to previous studies. We found that status of the fashion industry of the two countries as it stands. That is, Japan is an advanced country of which fashion industry is domestic market-oriented while Korea is a small open economy that mainly focuses on the foreign market. Out of 31 proxy variables, Korea's fashion industry shows higher measurements relating to production and export than Japan, but Japan's fashion industry reports higher measurements than Korea in the fields of R&D, design and brand power, the rate of value added, the efficiency of companies and globalization. In order for Korea's fashion industry to achieve competitiveness in the global market, it should pursue the following development direction. First, it is very difficult for Korea to follow the footsteps of the U.S. and Japanese fashion industries that are able to take advantage of economies of scale, because Korea is smaller than those countries. Therefore, in the case of small economies such as Singapore, strengthening of international activities will practically improve domestic determinants that Korea should improve its domestic diamond by enhancing the current competitiveness of its international diamond. In other words, Korea needs to further endeavor to develop and expand global resources and markets as well as improve its competitiveness in terms of R&D, design and brand power, the rate of value-added, and the efficiency of companies. As the Korean fashion industry shows relatively advanced level of information technology and the fashion education system, it has considerable potential to grow. Korea is expected to have a huge growth potential since it has relatively higher level of information technology, fashion education system and activities than those of Japan in both the domestic diamond and international diamond. In particular, a better environment is laid out before Korea to gain competitiveness in the fashion industry due to the recently growing influence of the Korean Wave that Korea is expected to grow as a leader in the Asian market as well as in the global market.

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A Study on Breakdown Voltage of Double Gate MOSFET (DGMOSFET의 항복전압에 관한 연구)

  • Jung, Hak-Kee
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2012.05a
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    • pp.693-695
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    • 2012
  • This paper have presented the breakdown voltage for double gate(DG) MOSFET. The analytical solution of Poisson's equation and Fulop's breakdown condition have been used to analyze for breakdown voltage. The double gate(DG) MOSFET as the device to be able to use until nano scale has the adventage to reduce the short channel effects. But we need the study for the breakdown voltage of DGMOSFET since the decrease of the breakdown voltage is unavoidable. To approximate with experimental values, we have used the Gaussian function as charge distribution for Poisson's equation, and the change of breakdown voltage has been observed for device geometry. Since this potential model has been verified in the previous papers, we have used this model to analyze the breakdown voltage. As a result to observe the breakdown voltage, the smaller channel length and the higher doping concentration become, the smaller the breakdown voltage becomes. Also we have observed the change od the breakdown voltage for gate oxide thickness and channel thickness.

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Research on Efficiency of Western China's Universities under the "Double First-Class" Initiative ("더블 퍼스트 클래스"를 통한 중국 서부 대학의 연구 효율성에 관한 연구)

  • Youming Li;Jae-Yeon Sim
    • Industry Promotion Research
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    • v.8 no.4
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    • pp.257-266
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    • 2023
  • The research focuses on the provincial universities in the western region of China and investigates the research level of 12 provincial universities from 2017 to 2021, considering both static efficiency and dynamic efficiency. The static efficiency is examined using Data Envelopment Analysis (DEA), while the dynamic efficiency is analyzed using the Malmquist model. The analysis results are as follows: the scientific research efficiency of universities in the 12 western provinces is generally not high. Against the background of the "Double First-Class" construction, the overall efficiency of scientific research in universities is showing an increasing trend. The main reason for the increase in scientific research efficiency is the increase in scale efficiency in recent years. The total factor productivity (TFP) of research activities is influenced by the technology progress index and exhibits a pattern of initial increase, followed by a decline, and then an increase again. Research conclusion: Western colleges and universities should reasonably allocate resources for scientific research activities, perfect scientific research mechanisms, improve management standards, promote scientific innovation and corresponding achievements, and ultimately raise the scientific and technological level in western China.

A Digitized Decoupled Dual-axis Micro Dynamically Tuned Gyroscope with Three Equilibrium Rings

  • Xia, Dunzhu;Ni, Peizhen;Kong, Lun
    • Journal of Electrical Engineering and Technology
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    • v.12 no.1
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    • pp.385-395
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    • 2017
  • A new digitized decoupled dual-axis micro dynamically tuned gyroscope with three equilibrium rings (TMDTG) is proposed which can eliminate the constant torque disturbance (CTD) caused by the double rotation frequency of a driving shaft with a micro dynamically tuned gyroscope with one equilibrium ring (MDTG). A mechanical and kinematic model of the TMDTG is theoretically analyzed and the structure parameters are optimized in ANSYS to demonstrate reliability. By adjusting the thickness of each equilibrium ring, the CTD can be eliminated. The digitized model of the TMDTG system is then simulated and examined using MATLAB. Finally, a digitized prototype based on FPGA is created. The gyroscope can be dynamically tuned by adjusting feedback voltage. Experimental results show the TMDTG has good performance with a scale factor of $283LSB/^{\circ}/s$ in X-axis and $220LSB/^{\circ}/s$ in Y-axis, respectively. The scale factor non-linearity is 0.09% in X-axis and 0.13% in Y-axis. Results from analytical models, simulations, and experiments demonstrate the feasibility of the proposed TMDTG.

Investigation and Simulation Study on the Cascading Trip-off Fault of a Large Number of Wind Turbines in China on May 14, 2012

  • Qiao, Ying;Lu, Zong-Xiang;Lu, Ji;Ruan, Jia-Yang;Wu, Lin-lin
    • Journal of Electrical Engineering and Technology
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    • v.10 no.6
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    • pp.2240-2248
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    • 2015
  • The integration of the large-scale wind power brings great challenge to the stability of the power grid. This paper investigates and studies the fault on May 14, 2012 of the large-scale cascading trip-off of wind turbines in North China. According to the characteristics of the voltage variation, the fault process is divided into three stages: the pre-event stage, the critical stage before cascading, and the cascading stage. The scenes in the fault are reproduced, using the full-size actual power system model. Simulation models of double-fed induction generators (DFIGs) and SVCs including protection settings and controller strategies are carefully chosen to find out the reason of voltage instability in each stage. Some voltage dynamic that have never been observed before in the faults of the same kind are analyzed in detail, and an equivalent voltage sensitive dynamic model of DFIG is proposed for the fast computation. The conclusions about the voltage dynamics are validated by the actual PMU observation evidence.

Nonlocal dynamic modeling of mass sensors consisting of graphene sheets based on strain gradient theory

  • Mehrez, Sadok;Karati, Saeed Ali;DolatAbadi, Parnia Taheri;Shah, S.N.R.;Azam, Sikander;Khorami, Majid;Assilzadeh, Hamid
    • Advances in nano research
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    • v.9 no.4
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    • pp.221-235
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    • 2020
  • The following composition establishes a nonlocal strain gradient plate model that is essentially related to mass sensors laying on Winkler-Pasternak medium for the vibrational analysis from graphene sheets. To achieve a seemingly accurate study of graphene sheets, the posited theorem actually accommodates two parameters of scale in relation to the gradient of the strain as well as non-local results. Model graphene sheets are known to have double variant shear deformation plate theory without factors from shear correction. By using the principle of Hamilton, to acquire the governing equations of a non-local strain gradient graphene layer on an elastic substrate, Galerkin's method is therefore used to explicate the equations that govern various partition conditions. The influence of diverse factors like the magnetic field as well as the elastic foundation on graphene sheet's vibration characteristics, the number of nanoparticles, nonlocal parameter, nanoparticle mass as well as the length scale parameter had been evaluated.

Case Study on a Revised Career Fair at a Medical School Based on the Career Planning Process Model (진로계획과정모형에 기반한 충남대학교 의과대학 진로박람회 개선 사례)

  • So-young Lee;Jeong Lan Kim;Kukju Kweon
    • Korean Medical Education Review
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    • v.26 no.1
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    • pp.27-35
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    • 2024
  • Medical students' career choices hold significant importance at both individual and national levels. Therefore, Chungnam National University College of Medicine aimed to systematize its revised career fair in 2022, basing its efforts on a career planning process model. Chungnam National University College of Medicine sought to formalize the design process by utilizing the ADDIE model (analysis design, development, implementation, evaluation model) in developing programs for the career fair program. Throughout the entire process, the student support center and student council actively collaborated, striving to incorporate students' requests and opinions. They designed and developed a program for all stages of the career planning process. However, a new stage ("review & ref lection") was added to the existing 4-phase model, creating a transformed framework where this stage interacts with the original 4 phases. Each stage involved portfolios, career aptitude tests, career-related lectures, posters with introductory information about majors, and booths for each major. The revised career fair attracted double the expected participants (N=589). The program evaluation survey showed overall positive responses (N=135). Additionally, some factors in the Specialty Indecision Scale showed significant differences between before and after the career fair. The success of the newly developed career fair at Chungnam National University College of Medicine can be attributed to its systematic framework and the active involvement of students throughout the process. However, for aspects with long-term implications, such as "understand yourself " and "choose your specialty," there may be a need for supplementary programs.