• Title/Summary/Keyword: time of rising

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Minimization of Rising and Falling Times of A Boost Type Converter Output Voltage in Pulsed Mode Operation

  • Nho Eui-Cheol;Kim In-Dong;Joe Cheol-Je;Chun Tae-Won;Kim Heung-Geun
    • Proceedings of the KIPE Conference
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    • 2001.10a
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    • pp.286-290
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    • 2001
  • This paper describes an improved short-circuit protection method with a boost type rectifier using a multilevel ac/dc power converter. The output dc power of the proposed converter can be disconnected from the load within several hundred microseconds at the instant of short-circuit fault. Once the fault has been cleared the dc power is reapplied to the load. The rising time of the dc load voltage is as small as several hundred microseconds, and there is no overshoot of the dc voltage because the dc output capacitors hold undischarged state. The converter, which employs the proposed method, has the characteristics of a simplified structure, reduced cost, weight, and volume compared with a conventional power supply, which has frequent output short-circuits. Experimental results are presented to verify the usefulness of the proposed converter.

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A Study on Healing Environmental Elements of the Waiting space of Outpatient Department in Domestic General Hospital in Consideration of Patiences - Focused on General Hospitals in Seoul - (환자 중심적 측면에서 본 국내 종합병원 외래진료부 대기공간의 치유환경요소에 관한 연구 - 서울지역 종합병원을 중심으로 -)

  • Park, Min-Soo;Choi, Sang-Hun
    • Proceedings of the Korean Institute of Interior Design Conference
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    • 2005.05a
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    • pp.203-206
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    • 2005
  • Recently, it is not to much to say that the world of hospital architecture in Korea is in a time of transition that undergo big changes. Each hospital pursues their transformation not only for patiences' changing demands on medical services but to cope with rapid environmental changes that pouring like boundless competition, opening tendency and to get an advantage of competition to attract patiences with other hospitals. It is because national expectations and standards on medical services have risen and they are not satisfied with hospitals that run for doctors and medical care that served technically any more. With rising interests in health, it is emphasized not the functions of hospitals to prevent diseases but the purpose of treatment and securing other facilities according to rising economical incomes except medical facilities.

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Moving-load dynamic analysis of AFG beams under thermal effect

  • Akbas, S.D.
    • Steel and Composite Structures
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    • v.42 no.5
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    • pp.649-655
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    • 2022
  • In presented paper, moving load problem of simply supported axially functionally graded (AFG) beam is investigated under temperature rising based on the first shear beam theory. The material properties of beam vary along the axial direction. Material properties of the beam are considered as temperature-dependent. The governing equations of problem are derived by using the Lagrange procedure. In the solution of the problem the Ritz method is used and algebraic polynomials are used with the trivial functions for the Ritz method. In the solution of the moving load problem, the Newmark average acceleration method is used in the time history. In the numerical examples, the effects of material graduation, temperature rising and velocity of moving load on the dynamic responses ofAFG beam are presented and discussed.

Eating Behavior of University Students by Economic Environment (남녀 대학생의 식행동에 관한 연구(II) -경제적 환경을 중심으로-)

  • Kim Myung-Sun
    • Korean journal of food and cookery science
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    • v.21 no.2 s.86
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    • pp.125-138
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    • 2005
  • The purposes of this study were to determine what kinds of food university students had, how often they were eating out and how much they consumed. A questionnaire survey was conducted on 597 university students (male $40.9\%$, female : $51.9\%$). The students who spent under 200 thousand won per month had regular meals at breakfast, lunch and dinner. The students with personal monthly spending over 300 thousand won, both male and female, ate out more than others. The female students had more protein foods than the male students. Consumption of milk and milk products increased with rising monthly spending for female students. Regardless of monthly spending, the male students ate seaweeds low in 1-2 time per a week. Consumption of rice decreased with rising monthly spending for male and female students.

Nonlinear dynamic behavior of functionally graded beams resting on nonlinear viscoelastic foundation under moving mass in thermal environment

  • Alimoradzadeh, M.;Akbas, S.D.
    • Structural Engineering and Mechanics
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    • v.81 no.6
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    • pp.705-714
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    • 2022
  • The aim of this paper is to investigate nonlinear dynamic responses of functionally graded composite beam resting on the nonlinear viscoelastic foundation subjected to moving mass with temperature rising. The non-linear strain-displacement relationship is considered in the finite strain theory and the governing nonlinear dynamic equation is obtained by using the Hamilton's principle. The Galerkin's decomposition technique is utilized to discretize the governing nonlinear partial differential equation to nonlinear ordinary differential equation and then the governing equation is solved by using of multiple time scale method. The influences of temperature rising, material distribution parameter, nonlinear viscoelastic foundation parameters, magnitude and velocity of the moving mass on the nonlinear dynamic responses are investigated. Also, the buckling temperatures of the functionally graded beams based on the finite strain theory are obtained.

A Study on the Bubble Flow in the Gas-Liquid Plume (기-액 기둥에서 기포유동에 관한 연구)

  • Seo, Dong-Pyo;Hong, Myung-Seok;Oh, Yool-Kwon
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.2105-2108
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    • 2003
  • The characteristics of upward bubble flow were experimentally investigated in a liquid bath. In the present study, a thermal-infrared camera and high speed CCO camera were used to measure their temperature and local rising velocity, respectively. Heat transfer from bubble surface to water is largely completed within z=10mm from the nozzle, and then the temperature of bubble surface reaches that of water rapidly. The rising velocity of bubble was calculated for two different experimental conditions: 1) bubble flow without kinetic energy 2) with kinetic energy. Bubble flow without kinetic energy starts to undergo the effect of inertia force 10cm away from the nozzle. Whereas, kinetic energy is dominant before 30 cm away from the nozzle in bubble flow, but after this point, kinetic energy and inertial force are applied on bubble flow at the same time.

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High voltage Pulse Transformer for Pulsed Power Supply (펄스파워전원용 고전압 펄스변압기)

  • Kim, Jong-Hae;Ku, Chi-Wuk;Choi, Y.W.;Lee, H.S.;Rim, K.H.;Ko, Kwang-Cheol
    • Proceedings of the KIEE Conference
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    • 1998.07e
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    • pp.1755-1757
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    • 1998
  • Pulse transformers have been developed to apply for pulsed power technology as an alternative of a Marx generator. To obtain repetitive pulsed power generation, it is necessary to observe the rising time of output of pulse transformer. In this paper, using the equivalent circuit, The rising wave of output of pulse transformer is simulated for various input wave by using the Electromagnetic transient program(EMTP).

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Overload Criterion of Mineral-Oil-Immersed Distribution Transformers Rated 100kVA and Less (100kVA 이하 유입식 배전용변압기의 과부하 판정기준 설정)

  • Yun, Sang-Yun;Kim, Jae-Chul;Lee, Young-Suk;Park, Chang-Ho;Shon, Hwa-Young
    • Proceedings of the KIEE Conference
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    • 2001.11b
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    • pp.6-8
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    • 2001
  • This paper covers general recommendations for top-oil temperature rising of mineral-oil-immersed power distribution transformer rated 100kVA and less, manufactured in Korea. In order to analyze the top-oil temperature rising due to the distribution transformer loading we performed experiments for oil-immersed distribution transformer, manufactured in domestic at KERI(Korea Electrical Research Institute) from December 2000 to May 2001. The magnitude of loading were changed, and the top-oil temperatures for each time were measured. Finally, we present the overload criteria of distribution transformer for summer and winter season in domestic. respectively.

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우리나라 장수촌(長壽村)의 생활습관(生活習慣)과 음식문화(飮食文化)에 관(關)한 고찰(考察)

  • Lim, Chang Byum;Oh, Min-Seok;Song, Tae-Won
    • Journal of Haehwa Medicine
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    • v.11 no.1
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    • pp.237-256
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    • 2002
  • In view of the results that we studied about living and eating habit of korean old people who live in longevity village, we can make conclusion as follows. 1. They have regular rising time, bedtime and living routine. Their bedtime is between 9 to 11 and rising time is before 6. It goes to show that they are keeping regular hours. 2. Generally speaking, most of long life peoples are physical labor: agriculture, fishery, housework, etc. 3. They are in balance with their eating habit. The most favorite food of longevity village's old people is made from toenjang which is fermented soybean paste. 4. The geographical features of longevity village are mountain region, coast and island. 5. Most of people who live long are illiteracy and only a few people of them has finished elementary school course. Moreover, in case of illiteracy, there are more unschooled woman compare with both sexes.

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A Study on the Time-periodic Characteristics of Multi-Family Housing in Cheongju (청주지역 공동주택의 시기별 특성에 관한 연구)

  • Han, Jo-Dong;Rhee, Kang-Hoon
    • Journal of the Korean Institute of Rural Architecture
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    • v.3 no.3
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    • pp.57-67
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    • 2001
  • The evolution of multi-family housing in Cheongju can be divided by four stages which are a introduction period from 1972 to 1980, a popularization period from 1981 to 1989, a expansion period from 1990 to 1997, and a stagnation period after 1998. In the introduction period, the multi-family housings were mainly low-rise buildings because a government policy which focused on extension of the apartments for the low-income influenced multi-family housing constructions. During the popularization period, the multi-family housings were still low-rise but houses in various sizes were introduced. That was because the Housing Site Developments were started and private companies' participations followed them increasingly. As a result of vigorous participations of private companies and massive developments of housing sites, the multi-family housings in the expansion period started to show constructions of complex and trends of high density and high rising. Finally, in the stagnation period, a rate of the supply of the small houses, whose size was below $60m^2$ of exclusive, area was increased and extreme high-rise apartments emerged. High rising and density were the mainstream of the construction concepts. During this period, the growth of multi-family housing marked low. The reason was that a downturn in economy led private companies to shrink their constructions.

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