• Title/Summary/Keyword: Cross diffusion

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The study on the diffusion of Catholicism in the New World: focused on the relationship between the king and the pope (왕권과 교권의 대립을 통해 본 신대륙의 가톨릭 전파과정 연구)

  • LEE, Seong hun
    • Cross-Cultural Studies
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    • v.37
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    • pp.7-29
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    • 2014
  • The 'discovery' or 'conquest' of the New World in 1492 was the starting point of world history that irrevocably changed the fate of the Latin American continent. The global stream known as 'Columbian Exchange', which was the widespread inter-continental contacts, inter-civilizational conflicts, or bilateral communication, has rendered multifarious effects throughout many historical periods up to the very contemporary time. The propagation of Catholicism initiated along with this 'discovery' transformed Latin America of nowadays in the region that has the biggest Catholic population in the world. The previous studies in Korea regarding Latin American Catholicism has focused on the spread of Catholicism in relation to the European colonization, rather than analyzing the concrete and detailed ways in which Catholicism exerted tremendous influences in the whole continent. They were less attentive to various historical contexts in which the diffusion of Catholicism differed greatly according to cultural landscapes and political specificities. Thus, this essay attempts to examine the diffusion of Catholicism from the perspective of confrontation between royal authorities and the power of church. The essay points out that the royal communities and institutional authorities which facilitated the intial process of Catholic evangelization maintained antagonistic relationship with ecclesial powers. By delving into the gradual transformation of church systems, it reveals that Catholicism in Latin America became a major field for conquerors in power to attain economic and political dominance. And unlike the initial submission and hospitality, the religious convert of the indigenous people attested to the violent inhumanity and opposition. Therefore, the essay aims to pave a clearer way to the understanding of complicated dynamics and conflicts between Catholicism in Latin America and the establishment of Spanish colonization.

A comparison on the heat load of HTS current leads with respect to uniform and non-uniform cross-sectional areas

  • Han, Seunghak;Nam, Seokho;Lee, Jeyull;Song, Seunghyun;Jeon, Haeryong;Baek, Geonwoo;Kang, Hyoungku;Ko, Tae Kuk
    • Progress in Superconductivity and Cryogenics
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    • v.19 no.3
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    • pp.44-48
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    • 2017
  • Current lead is a device that connects the power supply and superconducting magnets. High temperature superconductor (HTS) has lower thermal conductivity and higher current density than normal metal. For these reasons, the heat load can be reduced by replacing the normal metal of the current lead with the HTS. Conventional HTS current lead has same cross-sectional area in the axial direction. However, this is over-designed at the cold-end (4.2 K) in terms of current. The heat load can be reduced by reducing this part because the heat load is proportional to the cross-sectional area. Therefore, in this paper, heat load was calculated from the heat diffusion equation of HTS current leads with uniform and non-uniform cross-sectional areas. The cross-sectional area of the warm-end (65K) is designed considering burnout time when cooling system failure occurs. In cold-end, Joule heat and heat load due to current conduction occurs at the same time, so the cross-sectional area where the sum of the two heat is minimum is obtained. As a result of simulation, current leads for KSTAR TF coils with uniform and non-uniform cross-sectional areas were designed, and it was confirmed that the non-uniform cross-sectional areas could further reduce the heat load.

Experimental Study on Carbon Corrosion of Gas Diffusion Layer in PEM Fuel Cell (고분자전해질형 연료전지 가스확산층의 탄소 부식에 관한 실험적 분석)

  • Ha, Taehun;Cho, Junhyun;Park, Jaeman;Min, Kyoungdoug;Lee, Eunsook;Jyoung, Jy-Young
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.11a
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    • pp.76.1-76.1
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    • 2010
  • Recently, many efforts to solve the durability problem of PEM fuel cell are carried on constantly. However, despite this attention, durability researches of gas diffusion layer (GDL) are not much reported yet. Generally, GDL of PEM fuel cell experiences three external attacks, which are dissolution of water, erosion of gas flow, corrosion of electric potential. In this study, among these degradation factors, carbon corrosion of electric potential was focused and investigated with accelerated carbon corrosion test. Through the test, it is confirmed that carbon corrosion occurred at GDL, and corroded GDL decreased a performance of operating fuel cell. The property changes of GDL were measured with various methods such as air permeability meter, pore distribution analyzer, thermo gravimetric analyzer, and tensile stress test to discover the effects of carbon corrosion. Carbon corrosion caused not only loss of weight and thickness, but also degradation of mechanical strength of GDL. In addition, to analysis the reason of GDL property changes, a surface and a cross section of GDL were observed with scanning electron microscope. After 100 hours test, the GDL showed serious damage in center of layer.

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An Experimental Study of Silica Particle Growth in a Coflow Diffusion Flame Utilizing Light Scattering and Local Sampling Technique (I) - Effects of Flame Temperature - (광산란과 입자포집을 이용한 동축류 확산화염 내의 실리카 입자의 성장 측정(I) - 화염온도의 영향 -)

  • Cho, Jaegeol;Lee, Jeonghoon;Kim, Hyun Woo;Choi, Mansoo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.9
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    • pp.1139-1150
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    • 1999
  • The evolution of silica aggregate particles in coflow diffusion flames has been studied experimentally using light scattering and thermophoretic sampling techniques. The measurements of scattering cross section from $90^{\circ}$ light scattering have been utilized to calculate the aggregate number density and volume fraction using with combination of measuring the particle size and morphology through the localized sampling and a TEM image analysis. Aggregate or particle number densities and volume fractions were calculated using Rayleigh-Debye-Gans and Mie theory for fractal aggregates and spherical particles, respectively. Of particular interests are the effects of flame temperature on the evolution of silica aggregate particles. As the flow rate of $H_2$ increases, the primary particle diameters of silica aggregates have been first decreased, but, further increase of $H_2$ flow rate causes the diameter of primary particles to increase and for sufficiently larger flow rates, the fractal aggregates finally become spherical particles. The variation of primary particle size along the upward jet centerline and the effect of burner configuration have also been studied.

Production of NO in Interacting Laminar Diffusion Flames (상호작용하의 층류 확산 화염에서 NO의 생성)

  • 전철균
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.1
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    • pp.190-199
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    • 1993
  • In order to find the effect of flame interaction on NO production, dual laminar diffusion flames issuing from two rectangular nozzles were investigated theoretically. Chemical equilibrium model and Zeldovich mechanism were used in numerical model. The effect of four major parameters on NO production were inspected. These parameters are nozzle spacing, Raynolds number, aspect ratio of nozle cross section and velocity of secondary flow. It is found that interaction of flames enhances production of n. It is also found that multiflames with large spacing, small aspect ratio and strong secondary flow product less n.

A Study on the Use Intention of Xiaomi in Korean Market

  • Jin, Peng-Ru;Lee, Jong-Ho
    • The Journal of Industrial Distribution & Business
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    • v.9 no.11
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    • pp.17-24
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    • 2018
  • Purpose - The portability, functionality, and convenience of smart phones are constantly updated. With the rapid popularization of users of mobile terminals, Xiaomi is also developing rapidly. In February 2015, the users of Xiaomi exceeded 100 million people. As a transnational industry, Xiaomi has developed rapidly in not only China but also Korea. However, through the literature review, there is no radmissible study on the Xiaomi mobile telephones in the Korean market, so it is necessary to study the Xiaomi mobile phones in Korean market. Research design, data, and methodology - Figure analysis of data and social science analytical software of IBM SPSS AMOS 23.0 and IBM Statistics 23.0 were used for all the data researched. Results - First, the innovative diffusion temperament and the compatibility of Xiaomi have positive impacts on achievement expectations and effort expectations. Second, the innovative diffusion temperament and the complexity of Xiaomi have negative impacts on achievement expectations and effort expectations. Third, the innovative diffusion characteristics and the relative superiority of Xiaomi have positive impacts on achievement expectations and effort expectations. Conclusions - Through the analysis of the prior study, the innovation acceptance characteristics consist of compatibility, complexity, relative superiority, observation possibility, and the attempt possibility; the technical acceptance characteristics consist of achievement expectations, effort expectations, social influence, promotion condition, the study conducts relevant research on the continued use intention and analyze the hypothesis of research model.

EXPERIMENTAL STUDY ON THE FLOW AND MIXTURE DISTIBUTION IN A VISUALIZATION ENGINE USING DIGITAL PARTICLE IMAGE VELOCIMETRY AND ENTROPY ANALYSIS

  • Lee, K.H.;Lee, C.H.
    • International Journal of Automotive Technology
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    • v.8 no.2
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    • pp.127-135
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    • 2007
  • The objective of this study is to analyze the effect of velocity and vorticity on stratified mixture formation in the visualization engine. In order to investigate spray behavior, the pray velocity is obtained through the cross-correlation PIV method, a useful optical diagnostics technology and the vorticity calculated from the spray velocity component. These results elucidated the relationship between vorticity and entropy, which play an important role in the diffusion process for the early injection case and the stratification process for the late injection case. In addition, we quantified the homogeneous diffusion ate of spray using entropy analysis based on Boltzmann's statistical thermodynamics. Using these methods, we discovered that the homogeneous mixture distribution is more effective as a momentum dissipation of surrounding air than that of the spray concentration with a change in the injection timing. We found that the homogenous diffusion rate increased as the injection timing moved to the early intake stroke process, and BTDC $60^{\circ}$ was the most efficient injection timing for the stratified mixture formation during the compression stroke.

Neutronic simulation of the CEFR experiments with the nodal diffusion code system RAST-F

  • Tran, Tuan Quoc;Lee, Deokjung
    • Nuclear Engineering and Technology
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    • v.54 no.7
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    • pp.2635-2649
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    • 2022
  • CEFR is a small core-size sodium-cooled fast reactor (SFR) using high enrichment fuel with stainless-steel reflectors, which brings a significant challenge to the deterministic methodologies due to the strong spectral effect. The neutronic simulation of the start-up experiments conducted at the CEFR have been performed with a deterministic code system RAST-F, which is based on the two-step approach that couples a multi-group cross-section generation Monte-Carlo (MC) code and a multi-group nodal diffusion solver. The RAST-F results were compared against the measurement data. Moreover, the characteristic of neutron spectrum in the fuel rings, and adjacent reflectors was evaluated using different models for generation of accurate nuclear libraries. The numerical solution of RAST-F system was verified against the full core MC solution MCS at all control rods fully inserted and withdrawn states. A good agreement between RAST-F and MCS solutions was observed with less than 120 pcm discrepancies and 1.2% root-mean-square error in terms of keff and power distribution, respectively. Meanwhile, the RAST-F result agreed well with the experimental values within two-sigma of experimental uncertainty. The good agreement of these results indicating that RAST-F can be used to neutronic steady-state simulations for small core-size SFR, which was challenged to deterministic code system.

TRAVELING WAVES OF AN SIRS EPIDEMIC MODEL WITH SPATIAL DIFFUSION AND TIME DELAY

  • Du, Yanke;Xu, Rui
    • Journal of applied mathematics & informatics
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    • v.30 no.3_4
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    • pp.635-646
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    • 2012
  • This paper is concerned with an SIRS epidemic model with spatial diffusion and time delay representing the length of the immunity period. By using a new cross iteration scheme and Schauder's fixed point theorem, we reduce the existence of traveling wave solutions to the existence of a pair of upper-lower solutions. By constructing a newfashioned pair of upper-lower solutions, we derive the existence of a traveling wave solution connecting the uninfected steady state and the infected steady state.

Characteristics of Electron Transport in $SiH_4$ Gas used by MCS-BEq Algorithm (MCS-BEq 알고리즘에 의한 $SiH_4$ 기체의 전자수송특성)

  • Kim, Sang-Nam;Seong, Nak-Jin
    • Proceedings of the KIEE Conference
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    • 2006.10b
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    • pp.159-162
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    • 2006
  • In this paper energy distribution function in $SiH_4$ has been analysed over the E/N range 0.5${\sim}$300Td and Pressure value 0.5, 1.0, 2.5 Torr by a two-term approximation Boltzmann equation method and by a Monte Carlo simulation. The motion has been calculated to give swarm parameters for the electron drift velocity, diffusion coefficient, electron ionization, mean energy and the electron energy distribution function. The electron energy distribution function has been analysed in $SiH_4$ at E/N=30, 50Td for a case of the equilibrium region in the mean electron energy and respective set of electron collision cross sections. The results show that the deduced electron drift velocities, the electron ionization or attachment coefficients, longitudinal and transverse diffusion coefficients and mean energy agree reasonably well with theoretical for a rang of E/N values.

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