• Title/Summary/Keyword: shrinking

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Kinetic study of high-temperature removal of $H_2S$ by Ca-based sorbents (황화수소 제거를 위한 칼슘계 고온탈황제의 황화반응속도에 관한 연구)

  • 김영식;전지환
    • Proceedings of the Korean Environmental Sciences Society Conference
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    • 1998.04a
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    • pp.144-153
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    • 1998
  • Sorbents of calcined limestone and oyster particles having a diameter of about 0.63mm were exposed to simulate fuel gases containing 5000ppmv H2S for temperatures ranging from 600 to 800C in a TGA. The reaction between CaO and H2S proceds via an unreacted shrinking core mechanism. The sulfidation rate is likely to be controlled primarily by countercurrent diffusion through the product layer of calcium sulfide(CaS) formed. The kinetics of the sorption of H2S by CaO is sensitive to the reaction temperature and particle size, and the reaction rate of oyster was faster than the calcined limestone.

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Pipe Surface Reconstruction Using Shrinking (수축을 이용한 파이프 곡면의 복원)

  • Lee, In-Kwon
    • Journal of the Korea Computer Graphics Society
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    • v.5 no.2
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    • pp.1-7
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    • 1999
  • We present an algorithm to reconstruct a pipe surface from a set of unorganized points. A pipe surface is defined by a spine curve and a radius of a swept sphere. In this paper, by using the shrinking and moving least-squares methods, a point cloud is reduced to a thin curve-like point set that can be easily approximated with a spine curve of a pipe surface. The distance between a point in the thin point cloud and a corresponding point in the original point set represents the radius of a swept sphere of a pipe surface.

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PVT Measurement and Phase Transition Behavior of Dimer Liquid Crystals (이량체액정의 PVT측정과 상전이 거동)

  • 남수용
    • Journal of the Korean Graphic Arts Communication Society
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    • v.14 no.1
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    • pp.17-29
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    • 1996
  • N-substituted acrylamide hydrogel is reported to have the feature of bing transparent and sensitive enough to response to a temperature stimulus below the temperature of phase transition. Especially at the near of 35 C it becomes shrunk and opaque very quickly. It has also the characteristic of reversing swelling and shrinking. The experiment showed that it is possible to produce a functional gel of super water absorption with the process of free radical polymerizing PVA(polyvinylalcohol) and PAA(polyacrylamide), and crosslinking. The ratio of shrinking and swelling caused by copolymerization rises 10% to 80% at the each temperature of 20 C, 30 C, 40 C, respectively. Phase transition temperature of this gel by copolymerization is50 C while that of ordinary N-substituted acrylamides is between 32~35 C. This temperature reaches the rearing limit of animals and plants so that volumetric transition polymer gel can be ulilized in varying fields such as agriculture/gardening which are water-using field, on-off switch sensing temperature and volumetric variation, processing of liquid wastes and civil engineering works, architecture and electronics. We have no doubt that this material will be the high-functional resin in the hi-tech age of the near future.

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Strong Convergence of Modified Iteration Processes for Relatively Weak Nonexpansive Mappings

  • Boonchari, Daruni;Saejung, Satit
    • Kyungpook Mathematical Journal
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    • v.52 no.4
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    • pp.433-441
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    • 2012
  • We adapt the concept of shrinking projection method of Takahashi et al. [J. Math. Anal. Appl. 341(2008), 276-286] to the iteration scheme studied by Kim and Lee [Kyungpook Math. J. 48(2008), 685-703] for two relatively weak nonexpansive mappings. By letting one of the two mappings be the identity mapping, we also obtain strong convergence theorems for a single mapping with two types of computational errors. Finally, we improve Kim and Lee's convergence theorem in the sense that the same conclusion still holds without the uniform continuity of mappings as was the case in their result.

Shrink-Wrapped Boundary Face Algorithm for Mesh Reconstruction from Unorganized Points

  • Koo, Bon-Ki;Choi, Young-Kyu;Chu, Chang-Woo;Kim, Jae-Chul;Choi, Byoung-Tae
    • ETRI Journal
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    • v.27 no.2
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    • pp.235-238
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    • 2005
  • A new mesh reconstruction scheme for approximating a surface from a set of unorganized 3D points is proposed. The proposed method, called a shrink-wrapped boundary face (SWBF) algorithm, produces the final surface by iteratively shrinking the initial mesh generated from the definition of the boundary faces. SWBF surmounts the genus-0 spherical topology restriction of previous shrink-wrapping-based mesh generation techniques and can be applied to any type of surface topology. Furthermore, SWBF is significantly faster than a related algorithm of Jeong and others, as SWBF requires only a local nearest-point-search in the shrinking process. Our experiments show that SWBF is very robust and efficient for surface reconstruction from an unorganized point cloud.

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Development of a CAD program for optimal design of a cylinderical die with one stress-ring (단일보강링 원통형 금형의 최적 설계용 CAD 프로그램 개발)

  • 신중호;손주리;류갑상
    • 제어로봇시스템학회:학술대회논문집
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    • 1988.10a
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    • pp.556-561
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    • 1988
  • Shrink-rings (Stress-rings) are used in the fabrication of dies for cold forming and powder compaction processes to increase the allowable pressures for a given die material. Optimum procedures are to minimize a die thickness under the conditions that the stress distributions in the die and stress-rings utilize fully the strength available in each of the die elements. This paper proposes a new approach, where the maximum allowable shrinking pressures are calculated on shrinkage plans in the radial direction and the fractional shrinking pressures below the maximum allowable pressures are used as the design values. Two criteria for the optimal die design are used: Maximum shear stress limit for one-piece dies and zero tensile stress limit for combined dies. A computer program, DIECOM, is developed for illustrating the computer-aided design procedures. Finally, examples for each case are presented in this paper.

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Attack using Phase Shifts of Shrunken Sequence (수축수열의 위상이동차 공격법)

  • Choi, Un-Sook;Cho, Sung-Jin;Hwang, Yoon-Hee;Kim, Han-Doo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.6 no.1
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    • pp.97-104
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    • 2011
  • Pseudo-random sequences with high linear complexity and low correlation function values are widely used in communication and cryptology. In this paper, we study the properties of interleaved sequences generated by shrinking generator. And we give a method for obtaining the shrunken sequence from a partial description of the shrunken sequence by using the phase shifting of PN sequences generated by shrinking generator.

Fundamental Properties of Mortar and Wall Sand Coat Wall Materials Mixed with Eco-Friendly Plaster Material (친환경 미장재료로서 사벽재료를 혼입한 모르타르 및 벽체의 기초적 물성)

  • Liao, Xiao-Kai;Kim, Dong-Hun;Lim, Nam-Gi
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.05a
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    • pp.133-134
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    • 2017
  • The In the experiment on flow using sand walls, when white clay+sand was mixed with glutinous rice, traditional paper and seaweed as adherents and preventive measures for cracks, the flow was higher than other sand wall mortars. This indicates that it is effective in improving flow. Moreover, in terms of strength, a mix of white clay+sand, traditional paper and flour had a greater strength than a mix of white clay+sand, straws and flour. In the experiment to test for cracks and shrinking during drying, a composition of white clay+sand+traditional paper showed fewer cracks and less shrinking than the walls where straws were mixed in.

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Restructuring of the Off-Shore Otter Trawl Fishery in Korea (우리나라 근해저인망어업의 축소재편에 관한 고찰)

  • KIM, Dae-Young;KIM, Byoung-Ho
    • Journal of Fisheries and Marine Sciences Education
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    • v.16 no.1
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    • pp.124-141
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    • 2004
  • This study focuses on the off-shore trawl fishery, specifically on its restructuring and new regulations governing its operation since the 1990s. This fishery has an important role in terms of fishing capacity and production amount and is dependent on close diplomatic relations with adjacent fishing countries. The off-shore trawl fishery has been shrinking since the 1990s. In addition to a decrease in stock and an increase in imports, there are vessel buyback programs and a decrease in fishing grounds related to a tri-lateral agreement among Korea, China and Japan which have sped up the shrinking of the fishery. In this processing, costs exceed the increase of revenue. Excess investments in fishing gear and salary for crews have lowered profits in this fishery. Considering the above, the off-shore otter trawl fishery should stop increases in production and restructure the fishery by coordinating fishing gear restrictions and fishing areas, and down-sizing management capacity.

Kinetic of High-Temperature Removal of $H_2S$ by Ca-based Sorbents (황화수소 제거를 위한 칼슘계 고온 탈황제의 황화반응속도)

  • 김영식;전지환;손병현;정종현;정덕영;오광중
    • Journal of Environmental Science International
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    • v.8 no.1
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    • pp.125-133
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    • 1999
  • Sorbents of calcined limestone and oyster particles having a diameter of about 0.63mm were exposed to simulated fuel gases containing 5000ppm $H_2S$ for temperatures ranging from 600 to 80$0^{\circ}C$ in a TGA (Thermalgravimetric analyzer). The reaction between CaO and $H_2S$ proceeds via an unreacted shrinking core mechanism. The sulfidation rate is likely to be controlled primarily by countercurrent diffusion through the product layer of calcium sulfide(CaS) formed. The kinetics of the sorption of $H_2S$ by CaO is sensitive to the reaction temperature and particle size, and the reaction rate of oyster was faster than the calcined limestone.

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