• Title/Summary/Keyword: SHARP

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A Taxonomic Review of the Genus Laccophilus Leach (Coleoptera: Dytiscidae: Laccophilinae) in Korea (한국산 깨알물방개속(딱정벌레목 : 물방개과 : 깨알물방개아과)의 분류학적 재검토)

  • LEE, Dae-Hyun;AHN, Kee-Jeong
    • Korean journal of applied entomology
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    • v.54 no.2
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    • pp.63-71
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    • 2015
  • A taxonomic review of Korean Laccophilus Leach is presented. Five species are recognized, three of which [L. hyalinus (De Geer), L. lewisius Sharp and L. minutus ($Linn{\acute{e}}$)] previously recorded in Korea are incorrect identification of L. vagelineatus Zimmermann, L. lewisioides Brancucci and L. difficilis Sharp, respectively. Habitus and SEM photographs, key and diagnoses of the species are provided.

Development of an Algorithm Preserving Sharp-Edges of Control Meshes in the Doo-Sabin Subdivision Scheme (조정 메쉬의 각진 모서리를 유지하기 위한 수정 Doo-Sabin 곡면 분할 알고리듬 개발)

  • 이현찬;주병준;홍충성
    • Korean Journal of Computational Design and Engineering
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    • v.8 no.1
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    • pp.1-9
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    • 2003
  • Recently, designing 3D objects using various modeling techniques become getting more important issues in related industrial fields. The subdivision scheme is a technique that generates a smooth sur-face through many times of refinement processes that split polygons of control mesh into several smaller polygons. In this paper, we propose a new subdivision algorithm that preserves sharp-edges of control mesh after several refinement processes in the Doo-Sabin subdivision scheme. Using the pro-posed algorithm, the Doo-Sabin subdivision scheme can be well applied to modeling 3D objects with sharp-edges.

Fabrication of ultra-sharp tungsten tip using electro-chemical etching system (전기화학적 에칭방법을 이용한 초미세 바늘 전극 제작)

  • 오현주;장동영;강승언
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.04a
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    • pp.449-452
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    • 2004
  • To obtain the ultra-sharp tungsten tip, an analog to digital converter circuit aided by a personal computer has been setup. At the moment the lower part of the needle drops off during the etching process, a maximum current change across the reference resistor is detected by the PC interface card and the applied voltage is then cut off within a few milliseconds. Out experiment has been able to fabricate an ultra-sharp tungsten tip ~200 $\AA$ radius with a higher reproduction rate and reliability than the conventional method.

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A study on the C-shape Sharp Turn of fish robot according to biological mimic (생물학적 모방에 따른 물고기 로봇의 빠른 방향 전환 연구)

  • Park, Jin-Hyun;Lee, Tae-Hwan;Choi, Young-Kiu
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.15 no.12
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    • pp.2626-2631
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    • 2011
  • CST(C-shape sharp turn) represented the motion whereby fish bend their tail quickly in a C-shape to achieve an emergent changing of its swimming direction on fish swimming. But there is not yet the general motion trajectory functions related to CST. In this paper, we proposed the very simple motion functions related to CST sequence recorded from a real fish by biologists. Through the computer simulations, we confirmed the usefulness of the proposed function.

Mechanical behavior and buckling failure of sharp-notched circular tubes under cyclic bending

  • Lee, Kuo-Long
    • Structural Engineering and Mechanics
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    • v.34 no.3
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    • pp.367-376
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    • 2010
  • In this paper, an experimental investigation of the mechanical behavior and buckling failure of sharp-notched circular tubes subjected to cyclic bending is discussed. The unnotched and sharp-notched circular tubes of SUS 304 stainless steel were tested under symmetric curvature-controlled cyclic bending. It was found from moment-curvature curves that the loops show cyclic hardening and gradually steady after a few cycles for all tested tubes. The ovalization-curvature curves show an unsymmetric, ratcheting and increasing manner with the number of cycles. In addition, it was found that six almost parallel lines corresponding to unnotched and five different notch-depth (0.2, 0.4, 0.6, 0.8 and 1.0 mm) tubes were noted from the experimental relationship between the cyclic controlled curvature and the number of cycles necessary to produce buckling on a log-log scale. An empirical formulation was proposed so that it could be used for simulating the aforementioned relationship. By comparing with the experimental finding, the simulation was in good agreement with the experimental data.

Flexural Vibration Analysis of Mindlin Rectangular Plates Having V-notches or Sharp Cracks (V노치 또는 예리한 균열을 가지는 Mindlin 직사각형 평판의 휨 진동해석)

  • Kim, Joo-Woo;Jung, Eui-Young;Kim, Seung-Hyun
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2003.04a
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    • pp.35-42
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    • 2003
  • This paper provides the first known flexural vibration data for thick (Mindlin) rectangular plates having V-notches. The V-notch has bending moment and shear force singularities at its sharp corner due to the transverse vibratory bending motion. Based upon Mindlin plate theory, in which transverse shear deformation and rotary inertia effects are considered, the Ritz procedure is employed with a hybrid set of admissible functions assumed for the rotational and transverse vibratory displacements. This set includes: (1) a mathematically complete set of admissible algebraic-trigonometric polynomials which guarantee convergence to exact frequencies as sufficient terms are retained; and (2) an admissible set of Mindlin corner functions which account for the bending moment and shear force singularities at the sharp corner of the V-notch. Extensive convergence studies demonstrate the necessity of adding the Mindlin corner functions to achieve accurate frequencies for rectangular plates having sharp V-notches.

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A Study on the Properties of Commercial Zippers (시판지퍼의 물성에 관한 연구)

  • Joo Jeong Ae;Cha Ok Seon
    • Journal of the Korean Society of Clothing and Textiles
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    • v.9 no.2
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    • pp.35-43
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    • 1985
  • The purpose of this study was to analyse the characteristics and the problems of commercial zippers such as polyester coil zippers, plastic zippers and brass zippers by testing their properties. The sizes of the samples used for this were $\sharp$3, $\sharp$5 and $\sharp$8($\sharp$7 only in case of brass zippers), and all of them were selected in the same lot and collected from 4 different domestic companies. Original samples and another samples laundered 1, 3, 5 and 10 times were measured in terms of colorfastness, durability of coating of zipper, longitudinal dimensional change, operability of zipper, strength of zipper chain crosswise, and reciprocating movement of zipper. In conclusion, the properties of the zippers were revealed differently according to their kinds. Therefore, it was recommended that the present test standard should be modified, in order to improve them in quality.

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Sharp Edge Tool Alignment for Micro Pattern Machining (마이크로 패터닝 가공을 위한 공구 정렬에 관한 연구)

  • Park, Soon-Sub;Won, Jong-Ho
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.8 no.3
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    • pp.1-6
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    • 2009
  • This paper presents a geometrical error compensation of tool alignment for sharp edge bite on B axis controlled machine. In precision micro patterning, bite alignment is crucial parameter for machined surface. To decrease bite alignment error, plus tilted bite from B axis center is touched to reference work piece(pin gauge) and checked the deviation from original position. Same process is repeated for maximum touch deviation value. From this touched position value, wheel alignment error in X axis and Z axis can be calculated on B axis center. Experimental results show that this compensation method is efficient to correct sharp edge bite alignment.

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A study of CWR on railway viaduct with sharp curves (철도고가교 급곡선부 레일장대화 방안연구)

  • 이상진;김기훈;신순호;이주헌
    • Proceedings of the KSR Conference
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    • 2000.05a
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    • pp.415-422
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    • 2000
  • The Seoul Subway Line 4 crossing downtown diagonally constructed in February 1980 and opened on October 11, 1983. The line 4 is thus able to link southern and northern parts of Seoul with the downtown as well as with the Seoul outskirts. More than 810,000 people use it everyday. Line 4 was constructed like Line 1,2,3 with ballast track system causing much maintenance cost gradually and espicially much public discontent due to wheel and rail contact noise by railway viaduct with sharp curves. CWR on railway viaduct with sharp curves, 180m$\leq$R$\leq$300m, hasn't been designed and constructed ever in domestic. Therefore in order to reduce noise and vibration caused by interaction between wheel and rail the possibility and the methods of CWR(Continuous Welded Rail) on railway viaduct with sharp curve less than R300 will lead it to the maintenance free system.

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Taxonomy of the Korean Oxyporinae (Insecta, Coleoptera, Staphylinidae) (한국산 입치레반날개아과 (곤충강, 딱정벌레목, 반날개과) 의 분류)

  • Wook-Sun Hwang;Kee-Jeong Ahn
    • Animal Systematics, Evolution and Diversity
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    • v.16 no.2
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    • pp.191-202
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    • 2000
  • A taxonomic study of the Oxyporinae including a single genus Oxyporus Fabricius in Korea is presented. Members of the genus are known to be obligate inhabitants on fleshy mushrooms. They are characterized by crescent-shaped last labial palpomere. Nine species are recognized, five of which are reported for the first time in Korea (Oxyporus basicornis Cameron, O. basiventris Jarrige, O. crocatus Fauvel, O. niger Sharp, O. triangulum Sharp). The illustrations, descriptions, and key to the Korean species of the Oxyporinae are presented.

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