• Title/Summary/Keyword: Product surface

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TENSOR PRODUCT SURFACES WITH POINTWISE 1-TYPE GAUSS MAP

  • Arslan, Kadri;Bulca, Betul;Kilic, Bengu;Kim, Young-Ho;Murathan, Cengizhan;Ozturk, Gunay
    • Bulletin of the Korean Mathematical Society
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    • v.48 no.3
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    • pp.601-609
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    • 2011
  • Tensor product immersions of a given Riemannian manifold was initiated by B.-Y. Chen. In the present article we study the tensor product surfaces of two Euclidean plane curves. We show that a tensor product surface M of a plane circle $c_1$ centered at origin with an Euclidean planar curve $c_2$ has harmonic Gauss map if and only if M is a part of a plane. Further, we give necessary and sufficient conditions for a tensor product surface M of a plane circle $c_1$ centered at origin with an Euclidean planar curve $c_2$ to have pointwise 1-type Gauss map.

An Analysis of the Twisting and Bending Extrusion Process of the Product with the Rectangular Section by the $ DEFORM^{TM}$-3D (사각단면을 가진 압출제품의 비틀림굽힘 압출가공법에 대한$ DEFORM^{TM}$-3D 해석)

  • 윤선홍
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1999.03b
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    • pp.115-118
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    • 1999
  • The twisting and bending extrusion process is developed by the $DEFORM^TM$-3D. Because the rectangular section of the extruded product has the symmetry line of cross-section area, the twisting and the bending of extruded product has not occurred. The product with the rectangular section is applied to the twisting and bending extrusion process through the twisted die surface and eccentricity die section. It is shown that the twisting of extruded product is caused by the twisted die surfaces and the bending of extruded product is causd by the eccentricity between the die section. The results by the analysis show that the twisting angle and the curvature of extruded products increases by the die twisting angle, the eccentricity, but decreases by the die length, and friction condition

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The Surface Roughness of Injection Product according to the change of Injection Conditions (성형조건에 따른 성형품의 표면 거칠기 변화)

  • Park, Joon-Hyoung;Kim, Kuy-Bok;Yoon, Se-Kwon;Lee, Hyeon-Woo;Kim, Sun-Kyung
    • Design & Manufacturing
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    • v.8 no.2
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    • pp.12-17
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    • 2014
  • Currently, injection molding process is a very useful technique that be applied to many field. And injection molding technology has been commercial based on many studies. However, there is no standard of surface roughness because there are few studies about surface technology of injection product. In addition, when designing the mold, changes of the core surface and the injection conditions are not considered. In this paper, change of surface according to the core and the injection conditions was compared with the surface of the injection product. Accumulation of these technologies will propose direction in mold design, manufacturing and injection molding technology.

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Effect of Small Surface Defects in the Starting Material on Product Quality after Drawing (원소재의 미소 표면결함이 인발공정에 미치는 영향)

  • Nam, C.H.;Lee, I.K.;Lee, J.K.;Joun, M.S.
    • Transactions of Materials Processing
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    • v.23 no.3
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    • pp.159-163
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    • 2014
  • In the current study, the effect of small surface defects in the starting material including roughness, indentations, or scratches, which are perpendicular to the direction of drawing, on the product quality is investigated using the finite element method. An axisymmetric defect is assumed. Such defects are defined by a cylindrical defect area and two tapered regions connecting the defect area to the non-defective area of the material. Various conditions for these initial surface defects are considered, including defect depth, defect slope and defect length. To describe the plastic deformation of the defect in detail during the simulation, local remeshing is applied. Based on the finite element results, defect disappearance maps were generated. It was found that defect disappearance is significantly dependent on the defect depth and the defect length coupled with the defect slope.

Development of New Generation Sea Surface Temperature

  • Hiroshi, Kawamura
    • Proceedings of the KSRS Conference
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    • 2002.10a
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    • pp.634-637
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    • 2002
  • In order to contribute to trial of the ocean weather forecasts, we have developed new generation sea surface temperature. It is clod free, high-spatial resolution daily SST product, which enables us to follow the movements of SST patterns relating to the oceanic variations. The product is produced through an objective analysis merging various infrared and microwave SST products.

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Theoretical Study of Cycloaddition Reactions of C60 on the Si(100)-2×1 Surface

  • Rashid, Mohammad Harun Or;Lim, Chul-Tack;Choi, Cheol-Ho
    • Bulletin of the Korean Chemical Society
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    • v.31 no.6
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    • pp.1681-1688
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    • 2010
  • Density functional theory was adopted to study the various surface products and their reaction channels focusing on the on-dimer configuration which has not been suggested before. Energetic results show that the most stable on-dimer configuration is the 6,6-[2+2] structure which resembles the typical [2+2] cycloaddition product. The 6,6-[2+2] product is also more stable than any other possible surface structures of inter-dimer configuration further suggesting its existence. Potential energy surface scan along various possible initial surface reactions show that some of the possible on-dimer surface products require virtually no reaction barrier indicating that initial population of on-dimer surface products is thermodynamically determined. Various surface isomerization reaction channels exist further facilitating thermal redistribution of the initial surface products.

A Study on Extrusion Process of Cylindrical Product with Helical Fins Using Rotating Extrusion Die (회전압출다이를 사용한 헬리컬 핀붙이 원형단면 제품의 압출가공에 관한 연구)

  • Park S. M.;Jin I. T.
    • Transactions of Materials Processing
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    • v.14 no.5 s.77
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    • pp.444-451
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    • 2005
  • A new extrusion process of the circular section product with helical fins could be developed by rotating extrusion die. The twisting of extruded product is caused by the twisted conical die surface connecting the die entrance section and the die exit section linearly. But, until now, because the process has used fixed extrusion die, it needs high pressure in order to twist billet and form fin shape on the surface of billet. So, during extruding billet, in order not to twist billet, the extrusion die is needed to rotate itself instead of twisting of billet. It is known that it is possible to reduce extrusion load of product with helical fins by analysis and experiments using rotating die. And it is known that, through the extrusion load analysis by $DEFORM^{TM}-3D$ software, optimal rotational velocity of rotating die can be obtained according to reduction ratio of area and twisted angle of die. And experiments and analysis using rotating extrusion die show that the twisted angle of product can be controlled by twisted angle of extrusion helical die and the rotational velocity of extrusion helical die.

Experimental Study of Removing Surface Corrosion Products from Archaeological Iron Objects and Alternating Iron Corrosion Products by Nd:YAG Laser Cleaning System (Nd:YAG 레이저를 이용한 철제유물의 표면부식물 제거 및 성분 변화 연구)

  • Lee, Hye Youn;Cho, Nam Chul;Lee, Jong Myoung;Yu, Jae Eun
    • Korean Journal of Metals and Materials
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    • v.50 no.5
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    • pp.353-360
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    • 2012
  • The corrosion product of archaeological iron objects is supposed to be removed because it causes re-corrosion. So far it is removed by scapel and sand blaster but they depend on the skill and experience of a conservator and the glass-dust of the sand blaster is harmful to humans. Therefore this study applies a laser cleaning system which is used in various industrial cleaning processes, to remove corrosion product from archaeological iron objects. In addition, this work studies the alternation of corrosion product after laser irradiation, which evaluates the reliability of the laser cleaning system. Optical microscopy, SEM-EDS, XRD, Raman have been used to observe and analyse the surface of the objects. The results show the capacity of laser cleaning some corrosion product, but blackening appears with increasing pulses and laser energy, and some corrosion products, goethite and hematite, are partially altered to magnetite. These problems, blackening and alternation of corrosion product, should be solved by further studies which find the optimal laser irradiation condition and use a wetting agent.

Imfluence of Surface roughness on Rapid prototyping by FDM (FDM 장치에서 쾌속조형물의 형상이 표면 거칠기에 미치는 영향)

  • 전재억;정진서;하만경
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.1037-1041
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    • 2001
  • Competitive power is rapidly manufacture product required consumers. Therefore, modern industry have changed from small item many production to many item small production, rapid production is necessary thing at the product development. Thus, rapid prototyping is appeared. If the graphic model was made by CAD, the production can be made in short term. That provide what the part was directly tested by the worker. It provide believable data. This study is Imfluence of Surface roughness on Rapid prototyping by FDM(Fused deposition modeling).

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Effects of Surface Roughness on Atmospheric Corrosion of Galvanized Steel Sheets (아연도금 강판의 대기부식에 미치는 표면 거칠기의 영향)

  • 안진호;강성군;장세기
    • Journal of the Korean institute of surface engineering
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    • v.31 no.6
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    • pp.307-316
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    • 1998
  • The effects of surface roughness on chromate conversion coating and the corrosion behavior of galvanized steel sheets were investigated. Surface roughness was differently given to the galvanized steel sheets tested and these were then chromated. Accelerated corrosion test was conducted under the condition of $30^{\circ}C$, 90%RH with flowing 200ppm $SO_2$ gas. The galvanized steels were also exposed to urban environment for 5 weeks. The corrosion rates were measured by weight gain method. The distribution of chromate film and corrosion product on the coating were examined which SEM/EDS. The chromate film formed preferentially at the convex sites rather than at the concave sites on the surface. The corrosion products were found at the concave sites where the chromate film formed rarely. The corrosion product on the coating were found at the concave sites where the chromate film formed rarely. The corrosion rates increased slightly with the surface roughness in accelerated corrosion test but significantly in field test.

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