• Title, Summary, Keyword: non-symmetry

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A Study on the Extru-Bending Process of the Angle Product with non-Symmetric "ㄱ" Section (비대칭 "ㄱ" 단면 앵글제품의 압출굽힘 가공에 관한 연구)

  • 이경국;진인태
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.277-280
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    • 2003
  • It was investigated that the "ㄱ" type angle product could be bended with a curvature during extrusion by extru-bending process. The bending process for the "ㄱ" type angle product can be developed by the hot metal extru-bending machine with the two punches moving in the different velocity. Because of non-symmetry of product, it is important to design the ruled surface contour of dies cavity for the welding and bending with two billets. So it is designed that the multi-hole container has two non-symmetric holes and non-symmetric contour of dies entrance. The results of the experiment show that "ㄱ" type angle product can be bended by the extrusion process and that the curvature of the product can be controlled by the velocity of punch and that the defects such as the distortion of section and the thickness change of the product and the folding and wrinkling of the product did not happen after the bending processing by the extrusion bending machine.

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Comparison of Tension According to the Type of Sling Cord during the Bridging Exercise with Sling in Stroke Patients (뇌졸중 환자의 교각 운동 시 슬링 줄의 종류에 따른 장력 비교)

  • Jang, Gwonuk;Chang, Jongsung
    • Journal of Korean Medicine Rehabilitation
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    • v.29 no.2
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    • pp.189-194
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    • 2019
  • Objectives The purpose of this study was to examine comparison of tension according to the type of sling cord during the bridging exercise with sling in stroke patients. Methods Twenty six stroke patients were recruited for this study. Subjects were randomly performed sling bridging exercise with three types of sling cords such as nonelastic cord with affected side-nonelastic cord with non affected side (NC-NC), nonelastic cord with affected side-elastic cord with non affected side (NC-EC), and elastic cord with affected side-nonelastic cord with non affected side (EC-NC). They were measured tension with a tensiometer of sling cord during the bridging exercise with sling. Results The tension of sling cord was significantly different in affected side, non affected side, and tension ratio of affected side/non affected side. There were significant differences tension in NC-EC from NC-NC and EC-NC and the NC-EC method was increased tension of affected side and decreased tension of non affected side. Conclusions These results showed that the NC-EC method was improved the symmetry of affected side and non affected side. Sling exercise with appropriate type of sling cord should be increased activities of affected side and improved recovery in stroke patients.

Microstructural Characteristics of III-Nitride Layers Grown on Si(110) Substrate by Molecular Beam Epitaxy

  • Kim, Young Heon;Ahn, Sang Jung;Noh, Young-Kyun;Oh, Jae-Eung
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.327.1-327.1
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    • 2014
  • Nitrides-on-silicon structures are considered to be an excellent candidate for unique design architectures and creating devices for high-power applications. Therefore, a lot of effort has been concentrating on growing high-quality III-nitrides on Si substrates, mostly Si(111) and Si(001) substrates. However, there are several fundamental problems in the growth of nitride compound semiconductors on silicon. First, the large difference in lattice constants and thermal expansion coefficients will lead to misfit dislocation and stress in the epitaxial films. Second, the growth of polar compounds on a non-polar substrate can lead to antiphase domains or other defective structures. Even though the lattice mismatches are reached to 16.9 % to GaN and 19 % to AlN and a number of dislocations are originated, Si(111) has been selected as the substrate for the epitaxial growth of nitrides because it is always favored due to its three-fold symmetry at the surface, which gives a good rotational matching for the six-fold symmetry of the wurtzite structure of nitrides. Also, Si(001) has been used for the growth of nitrides due to a possible integration of nitride devices with silicon technology despite a four-fold symmetry and a surface reconstruction. Moreover, Si(110), one of surface orientations used in the silicon technology, begins to attract attention as a substrate for the epitaxial growth of nitrides due to an interesting interface structure. In this system, the close lattice match along the [-1100]AlN/[001]Si direction promotes the faster growth along a particular crystal orientation. However, there are insufficient until now on the studies for the growth of nitride compound semiconductors on Si(110) substrate from a microstructural point of view. In this work, the microstructural properties of nitride thin layers grown on Si(110) have been characterized using various TEM techniques. The main purpose of this study was to understand the atomic structure and the strain behavior of III-nitrides grown on Si(110) substrate by molecular beam epitaxy (MBE). Insight gained at the microscopic level regarding how thin layer grows at the interface is essential for the growth of high quality thin films for various applications.

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Oscillatory modes generated by Hopf bifurcations in coupled four oscillators

  • Kitajima, Hiroyuki;Kawakami, Hiroshi
    • Proceedings of the IEEK Conference
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    • pp.1634-1637
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    • 2002
  • We examine the oscillatory modes generated by the Hopf bifurcations of non-origin equilibrium points in the four-coupled oscillator system. The Hopf bifurcations of the equilibrium points and the generated oscillatory modes are classified. By numerical bifurcation analysis we observe various interesting synchronized states caused by symmetry-breaking bifurcations.

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Shaking Table Test of a Rectangular Liquid Storage Tank (직사각형 액체저장탱크의 동적 응답특성에 관한 진동대 실험)

  • 김재관
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.209-214
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    • 2000
  • Shaking table tests were performed to investigate dynamic behavior of a three dimensional flexible rectangular liquid storage tank. Response characteristics to the three components of translational motion and three component of rotational motion were studied. The aluminium tank was exposed to the shaking high enough to make it behave in nonlinear range. Only very limited amount of the data have been processed yet. Very interesting phenomena on the effects of non-symmetry have been observed and presented. Test results that show nonlinear behavior under the high intensity shaking are reported.

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A ROLE OF SINGLETONS IN QUANTUM CENTRAL LIMIT THEOREMS

  • Accardi, Luigi;Hashimoto, Yukihiro;Obata, Nobuaki
    • Journal of the Korean Mathematical Society
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    • v.35 no.3
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    • pp.675-690
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    • 1998
  • A role of singletons in quantum central limit theorems is studied. A common feature of quantum central limit distributions, the singleton condition which guarantees the symmetry of the limit distributions, is revisited in the category of discrete groups and monoids. Introducing a general notion of quantum independence, the singleton independence which include the singleton condition as an extremal case, we clarify the role of singletons and investigate the mechanism of arising non-symmetric limit distributions.

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MODULI SPACES OF ORIENTED TYPE ${\mathcal{A}}$ MANIFOLDS OF DIMENSION AT LEAST 3

  • Gilkey, Peter;Park, JeongHyeong
    • Journal of the Korean Mathematical Society
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    • v.54 no.6
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    • pp.1759-1786
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    • 2017
  • We examine the moduli space of oriented locally homogeneous manifolds of Type ${\mathcal{A}}$ which have non-degenerate symmetric Ricci tensor both in the setting of manifolds with torsion and also in the torsion free setting where the dimension is at least 3. These exhibit phenomena that is very different than in the case of surfaces. In dimension 3, we determine all the possible symmetry groups in the torsion free setting.

Characteristics of Flow past a Sphere in Uniform Shear (균일 전단유동 내에 위치한 구 주위의 유동특성)

  • Kim, Dong-Joo;Choi, Hyung-Seok;Choi, Hae-Cheon
    • Proceedings of the KSME Conference
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    • pp.1607-1612
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    • 2004
  • Numerical simulations are performed to investigate the characteristics of flow past a sphere in uniform shear. The Reynolds numbers considered are Re=300, 425 and 480 based on the inlet center velocity and sphere diameter. The non-dimensional shear rate K of the inlet uniform shear is varied from 0 to 0.15. At Re=300, the head of the hairpin vortex loop always locates on the high-velocity side in uniform shear, and the flow maintains the planar symmetry. At Re=425 and 480, the irregularity in the location and strength of the hairpin vortex appearing in uniform inlet flow is much reduced in uniform shear, but the flows still keep the asymmetry for most inlet shear rates. However, in the cases of K=0.075 and 0.1 at Re=425, the flows become planar symmetric and their characteristics of the evolution of the hairpin vortex loops are different from those of asymmetric flows. A hysteresis phenomenon switching from the planar symmetry to the asymmetry (or vice versa) depending on the initial condition is also observed at Re=425.

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A Study on the Vibration Characteristics of Symmetry, Asymmetry Laminated Composite Materials by using Time-Average ESPI (시간평균 ESPI를 이용한 대칭.비대칭 적층 복합재료의 진동 특성 비교에 관한 연구)

  • Hong Kyung-Min;Ryu Weon-Jae;Kang Young-Jung;Kang Shin-Jae
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.259-260
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    • 2006
  • The ESPI(Electronic Speckle Pattern Interferometry) is a real time, full-field, non-destructive optical measurement technique. In this study, ESPI is proposed for the purpose of vibration analysis for new material, composite material. Composite materials have various complicated characteristics according to the ply materials, ply orientations, ply stacking sequences and boundary conditions. Therefore, it is difficult to analysis composite materials. For efficient use of composite materials in engineering applications the dynamic behavior, that is, natural frequencies, nodal patterns should be informed. If use Time-Average ESPI, can analyze vibration characteristic of composite material by real time easily. This study manufactured laminated composite of symmetry, asymmetry two kinds that is consisted of CFRP(Carbon Fiber Reinforced Plastics) and shape of test piece is rectangular form.

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Correction of Retracted Ala Using Spacer Graft in Secondary Cleft Lip and Nose Deformity (이차 구순비 변형 환자에서 Spacer Graft를 이용한 콧방울뒤당김(retracted ala)의 교정)

  • Han, Kyu-Seok;Choi, Hyun-Gon;Shin, Dong-Hyeok;Kim, Soon-Heum;Hwang, Eun-A;Uhm, Ki-Il
    • Archives of Plastic Surgery
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    • v.38 no.4
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    • pp.376-382
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    • 2011
  • Purpose: In patients with unilateral cleft lip and nose deformity, alar retraction is commonly seen on the non-cleft side after cleft side is corrected. Spacer graft was used to drag down the inferior border of the alar cartilage of the non-cleft side so as to match the cleft side. By performing spacer graft and septal extension graft together, symmetry and cosmetic improvements were achieved. Methods: Seven unilateral cleft lip and nose deformity patients underwent surgery for alar retraction correction. The median age was 24 years (ranged from 15 to 34 years), and the median follow-up period was 7.4 months (ranged from 6 to 12 months). The perpendicular length from the longitudinal axis of the nostril to the alar rim, the nasolabial angle and the ala-labial angle were measured in the lateral view photo. The longest perpendicular length from the cephalic border of the alar rim to the parallel line of the alar base was measured in the frontal view photo. Results: Improvement in alar retraction was seen after the surgery. There were no specific complications during the follow-up and the symmetry of both nostrils was satisfactory. No increase in the nasolabial angle or exposure of the nostrils was seen after the tip projection via tip plasty. Conclusion: The fundamental factor in correcting alar retraction with secondary cleft lip and nose deformity is repositioning the alar rim with spacer graft, which seems to be more physiologic than other methods. The method combining spacer graft with septal extension graft will bring symmetry as well as more cosmetic improvement in correction of alar retraction with secondary cleft lip and nose deformity.