• Title, Summary, Keyword: Rectangular arrays

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The Number of Configuration on Rectangular Arrays

  • Park, Ji-Hyun
    • Communications of Mathematical Education
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    • v.11
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    • pp.297-305
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    • 2001
  • In this paper, we derive the formula that the number of configuration on the rectangular arrays is counted by the composite shift operator method.

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THE NUMBER OF CONFIGURATION ON RECTANGULAR ARRAYS

  • Park, Ji Hyun;Jung, Wan Soo;Park, Dae Yeon
    • Journal of the Chungcheong Mathematical Society
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    • v.8 no.1
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    • pp.95-104
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    • 1995
  • In this paper, we derive the formular that the number of configuration on the rectangular arrays is counted by the composite shift operator method.

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A Study on Mixed Convection in Parallel Flat Plate with Heated Rectangular Block Arrays (발열체가 있는 평행평판공간내의 대류열전달에 관한 수치해석)

  • Jung, B.Y.;Lee, C.M.;Yim, C.S.
    • Solar Energy
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    • v.6 no.2
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    • pp.62-69
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    • 1986
  • An analysis is made of the fully developed laminar flow and heat transfer in a parallel flat plate with heated rectangular block arrays to investigated the influence of bouyancy force. The shrouds is considered as adiabatic, while the heated block surface transmit a uniform rate of heat flux per unit axial length. The governing equations for velocity and temperature are solved by SIMPLE(Semi-Implicit Method Pressure Linked Equation) algorithm. Detailed velocity and temperature fields and overall heat transfer on wide range of Rayleigh number and various aspect ratios of heated rectangular blocks are computed. The result show that bouyancy leads to a significient enhancement in heat transfer along with a smaller increase in pressure drop, with the great enhancement found when the aspect ratio is 3.0.

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The Comparison of Field Uniformity and SAR between TEM, Loop and Combined Elemented 16 Channel Transmit Arrays (TEM 형과 Loop 형의 전송소자를 이용한 16채널 3T Body 전송코일의 자장 균일도와 안전도 비교)

  • Ryu, Yeunchul;Kim, Young Beom
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.3
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    • pp.404-408
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    • 2014
  • In this research we evaluate the excitation homogeneity and SAR of three different Tx arrays after B1+ Shimming in the human body at 3T. Through the simulations, we compared the field properties that are standard deviation and mean value of transverse magnetization for 1) strip line TEM array, 2) rectangular loop array, 3) combined array of strip line element and rectangular loop and shown the utilities of B1+ shimming in human body model. After B1+ shimming, it is evaluated four different types of SAR for body mesh through whole body simulation; those are average, maximum 1-cell, maximum 1-gram, and maximum 10-gram SAR. It appears that in this particular comparison an array based on strip line elements can produce better homogeneity and lower SAR than an array of rectangular loops or an array of combined elements (strip line and loop). While many factors are considered in designing coils for production, it is hoped that methods and results like these will be used in the future to guide decisions and maximize benefit.

Novel Fabrication of Nanoporous Alumina Membrane Microtubes: 2-Dimensional Nanoporous Arrays on Every Facets of Microtubes

  • Chae, Weon-Sik;Im, Sung-Jae;Lee, Jin-Kyu;Kim, Yong-Rok
    • Bulletin of the Korean Chemical Society
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    • v.26 no.3
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    • pp.409-412
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    • 2005
  • Free-standing nanoporous alumina membrane microtubes with different shapes (rectangular and cylindrical tubes) and variable dimensions were easily fabricated by direct anodization of the aluminum templates of the specified shapes (strip and wire) and dimensions during the electrochemical reaction.

The Effects of Tube Arrangement and Inclination on the Pressure Drop in Tube Bundles of Intermediate Beat Exchanger in Liquid Meta Reactor (액체금속로 중간열교환기 관다발에서의 튜브배열과 경사각도가 압력강하에 미치는 영향)

  • Nam Ho Yun;Kim Jong Man;Choi Jong Hyeun
    • Proceedings of the KSME Conference
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    • pp.659-662
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    • 2002
  • The present paper presents the experimental results for pressure drop in inclined tube bundles located in a rectangular duct. Measurements are made for pressure drop in triangular and rotated triangular tube arrays having P/d ratio of 1.6 and inclination angles of 30,45,60 and 90 degrees. The Reynolds number based on the free stream velocity and tube diameter ranges from $8{\times}10^2\;to\;6.3{\times}10^{4}$. The experimental results show that the magnitude of dimensionless pressure drop decreases significantly when the inclined angle is less than 45 degree. The measured data are compared with two existing correlations available in the literatures. The ESDU correlation agrees well with the present data far the triangular arrays. But some discrepancies are observed for the rotated triangular arrays when the inclined angles are 30 and 45 degrees. The Idel'chik correlation generally agrees well with the measured data for the rotated triangular arrays except for the inclined angle of 30 degree. The Idel'chik correlation needs modification for the triangular arrays. The modified Idel'chik correlation agrees well with the measured data within $10{\%}$. It is found that the present measured data can be applied to the evaluation and modification of previous correlations.

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Evaluation of Local Loss Coefficients for Different Waveguide-Below-Cutoff (WBC) Arrays of Electromagnetic Pulse (EMP) Shied in Buildings (도파관 배열에 의한 국부저항계수 산정)

  • Pang, Seung Ki;Chae, Young Tae
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.7
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    • pp.366-372
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    • 2017
  • The objective of this study was to characterize Waveguide-Blow-Cutoff (WBC) array for Electromagnetic Pulse (EMP) shield in air duct or water pipe, the typical pathway of pulse in indoor space with critical electronic device. A numerical investigation with three different WBC designs (circular, rectangular, and hexagonal or honeycomb) was conducted to satisfy recommended shielding effectiveness (SE) levels from 80 dB to 140 dB. Pressure drop between upstream and downstream of EMP shields based on WBC arrays was also investigated to understand air flow feature in air duct of HVAC system. Results showed that honeycomb geometry outperformed other shapes in terms of reducing the depth of EMP shield, thus providing better air flow in duct path with lower local loss coefficient in HVAC system under SE requirements.

Color Tunable Nanostructures by Polarization Control for Display Applications

  • Cho, Eun-Byurl;Ko, Yeong-Il;Yeo, Jong-Souk
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.567-567
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    • 2013
  • Surface plasmon resonance is the enhancement of electromagnetic wave caused by oscillation on the metal and dielectric interfaces. Surface plasmons with nanohole arrays provides an enhancedresonance for the specific wavelengths of interests. Asymmetric array of nanoscale structures can enable orientation dependent shift of resonance wavelengths when combined with the control of polarization for incident visible light, thus providing color tunability. Appropriate lattice constants along the direction of polarization in rectangular nanohole arrays can determine the resonance condition generating red (R), green (G), and blue (B) colors and potentially be applied to display applications. In ourprevious report, we have optimized the ion beam nanomachining conditions to fabricate the nanostructures on the metal film. We apply the fabrication conditions to make nanoscale hole arrays using 100 nm thick gold layer on the glass substrate with the optimal design of periodicities along x, y, and diagonal directions of a=440 nm, b=520 nm, c=682 nm, and the hole diameter of d=200 nm. Using the reflective light in dark field mode of optical microscope, we can observe different colors. When the polarizer is paralleled along a, b, or c direction, the represented color is changed to R, G, and B, respectively. We further map the color using i1 to correlate the conditions of the nanohole arrays with their characteristic color.

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Analysis on Gu-il-jip, the mathematical book of Chosun dynasty and its pedagogical applications (조선시대의 산학서 <구일집>의 내용 분석 및 교육적 활용 방안 탐구)

  • 장혜원
    • Journal of Educational Research in Mathematics
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    • v.13 no.4
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    • pp.429-446
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    • 2003
  • Gu-il-jip is a mathematical book of Chosun dynasty in the 18c. It consists of nine chapters including more than 473 problems and their solutions. Analyzing the problems and their solutions, we can appreciate the mathematical researches by the professional mathematicians of Chosun. Especially, it is worth noting the followings: - units for measuring and decimal notations - $\pi$, area of circle, volume of sphere - naming the powers - counting rods - excess and deficit: calculation technique for excess-deficit relations among quantities - rectangular arrays: calculation technique for simultaneous linear equations - 'Thien Yuan' notation: method for representing equations - 'Khai Fang': algorithm for numerical solution of quadratic, cubic and higher equations Based on these analyses, some pedagogical applications are proposed.

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