• Title/Summary/Keyword: Stress resultant

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Study on the Address Discharge Characteristics for the Improvement of the Mis-firing Problem in AC PDP (AC PDP의 오방전 개선을 위한 어드레스 방전 특성 연구)

  • Jeon, Won-Jae;Kim, Dong-Hun;Lee, Seok-Hyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.6
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    • pp.1151-1156
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    • 2009
  • Unstable sustain discharges can occur at the bottom cells of the panel at high temperature. To solve this problem, the wall charge variation during an address period was investigated. A test panel of 7.5 inch XGA level was used and one green cell was measured. In order to realize operating condition equal to that of the bottom cells of 50 inch panel, the addressing stress pulses are applied. It seems that the resultant wall charge loss during address period increased with increase of stress time, temperature, pressure and Xe %. Wall charge loss increases with potential difference between scan electrode and address electrode, therefore wall charge loss can be minimized by the increase of scan voltage during address period.

A study on strength of internal gear (내접치차의 강도에 관한 연구)

  • 정태형
    • Journal of the korean Society of Automotive Engineers
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    • v.6 no.3
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    • pp.45-54
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    • 1984
  • Bending strength of an internal gear tooth is discussed as tooth form factor taking into account the actual stress magnitude. Stress analysis was carried out by the finite element method(FEM) for the calculation of tooth form factor of an internal gear. This paper also investigated the influences of number of teeth and addendum modification coefficient of the internal gear and the influences of number of teeth, addendum modification coefficient, pressure angle, radius of rounding of tooth tip, and bottom clearance coefficient of the pinion-shaped cutter on tooth form factor of internal gear. Generalizing the resultant data, a simple formula for the tooth form factor of an internal gear was derived for the calculation of tooth bending strength of an internal gear.

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Crystallization behavior of a-Si film using UV pulsed laser

  • Kim, Do-Young;Park, Kyung-Bae;Kwon, Jang-Yeon;Jung, Ji-Sim;Xianyu, Wenxu;Park, Young-soo;Noguchi, Takashi
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.656-660
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    • 2003
  • We studied the crystallization behavior of LP-CVD a-Si film using UV pulsed laser. With increase in the shot number of irradiation by fixing its energy density, poly-Si film having a large grain size of $0.5 {\mu}m$ was obtained. By analyzing the crystallized Si films using optical analysis such as Raman spectroscopy or AFM technique etc., conspicuous correlation between the grain size and the resultant film properties such as the stress or the roughness has been found. With the increase in the energy density or the shots number of laser, remarkable grain growth occurred following to the roughness formation corresponding to the increase in the tensile stress.

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Oxidative Stress and Antioxidant Defences in the Tasar Silkworm Antheraea mylitta D: Challenged with Nosema Species

  • Jena, Karmabeer;Pandey, Jay Prakash;Sinha, Ajit Kumar
    • International Journal of Industrial Entomology and Biomaterials
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    • v.28 no.2
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    • pp.85-91
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    • 2014
  • This study was designed to find out the effect of Nosema spore on oxidative damages and antioxidant defence in the midgut of tasar silkworm Antheraea mylitta. Higher level of lipid peroxidation (LPX) and total hydroperoxides indicate the resultant oxidative stress in the Nosema exposed specimen. Increased superoxide dismutase (SOD) suggests activation of physiological mechanism to scavenge the superoxide radical produced during Nosema infection. Higher activities of catalase and glutathione-S-tranferase on $18^{th}$ d indicate adaptive behaviour of the tissue against oxyradicals. The results suggest that Nosema infection is involved in altering the active oxygen metabolism by modulating LPX and reactive oxygen species (ROS), which is indicative of pebrine disease disorder.

Study on the Address Discharge Characteristics for the Analysis of the Unstable Discharge in AC PDP (AC PDP의 오방전 원인 분석을 위한 어드fp스 방전 특성에 관한 연구)

  • Kim, Dong-Hun;Jeon, Won-Jae;Lee, Seok-Hyun
    • Proceedings of the KIEE Conference
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    • 2007.11a
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    • pp.214-215
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    • 2007
  • Unstable sustain discharges can occur at the bottom cells of the panel at high temperature. To solve this phenomenon, the wall charge variation during an address period was investigated. A test panel of 7.5 inch XGA level was used and one green cell was measured. In order to realize operating condition equal to that of the bottom cells of 50 inch panel, the addressing stress pulses are applied. It seems that the resultant wall charge loss during address period increased with increase of temperature as well as the addressing stress pulse voltage. Therefore it results in unstable discharge during sustain period.

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A Study on Behavior of Fracture and Stress Distribution in Spot Welds (점熔接材 의 破壞擧動 과 應力分布)

  • 송삼홍;김부동
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.8 no.3
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    • pp.224-231
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    • 1984
  • Having found by means of a tension-shear test an optimal spot welding condition under which the maximum weld strength is to be brought forth, this study made an examination of behavior of fracture concerned with behavior of stress distribution, observed around the nugget periphery of the specimens prepared under the optimal conditions, with one point spot welded mild steel sheets. The resultant findings are as follows: (1)There remarkably exists an optimal spot welding condition to indicate the maximum weld strength, and fracture of the specimens spot welded under that condition occurs outside the nugget boundary. (2)An experiment on the basis of a photoelastic model reveals that the maximum stress is distributed along the center line of the steel plate width but occurs on the region corresponding to heat affected zone of spot welds. (3)Heat affected zone of spot welds consists of coarse grains with considerably low micro Vickers hardness value and of fine grains of high micro Vickers hardness value, and in this unbalanced structure weak region are represented in coarse grain region, where fracture is initiated and continues its propagation.

Enhanced proline accumulation and salt stress tolerance of transgenic indica rice by over-expressing P5CSF129A gene

  • Kumar, Vinay;Shriram, Varsha;Kishor, P.B. Kavi;Jawali, Narendra;Shitole, M.G.
    • Plant Biotechnology Reports
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    • v.4 no.1
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    • pp.37-48
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    • 2010
  • [ ${\Delta}^1$ ]pyrroline-5-carboxylate synthetase (P5CS) is a proline biosynthetic pathway enzyme and is known for conferring enhanced salt and drought stress in transgenics carrying this gene in a variety of plant species; however, the wild-type P5CS is subjected to feedback control. Therefore, in the present study, we used a mutagenized version of this osmoregulatory gene-P5CSF129A, which is not subjected to feedback control, for producing transgenic indica rice plants of cultivar Karjat-3 via Agrobacterium tumefaciens. We have used two types of explants for this purpose, namely mature embryo-derived callus and shoot apices. Various parameters for transformation were optimized including antibiotic concentration for selection, duration of cocultivation, addition of phenolic compound, and bacterial culture density. The resultant primary transgenic plants showed more enhanced proline accumulation than their non-transformed counterparts. This proline level was particularly enhanced in the transgenic plants of next generation ($T_1$) under 150 mM NaCl stress. The higher proline level shown by transgenic plants was associated with better biomass production and growth performance under salt stress and lower extent of lipid peroxidation, indicating that overproduction of proline may have a role in counteracting the negative effect of salt stress and higher maintenance of cellular integrity and basic physiological processes under stress.

3-Node Relaxed-Equiribrium Hybrid-Mixed Curved Beam Elements (완화된 평형조건을 만족하는 응력함수를 가지는 3절점 혼합 곡선보요소)

  • Kim, Jin-Gon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.21 no.2
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    • pp.153-160
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    • 2008
  • In this study, we propose a new three-node hybrid-mixed curved beam element with the relaxed-equiribrium stress functions for static analysis. The proposed element considering shear deformation is based on the Hellinger-Reissner variational principle. The stress functions are carefully chosen from three important considerations: (i) all the kinematic deformation modes must be suppressed, and (ii) the spurious constraints must be removed in the limiting behaviors via the field-consistency, and (iii) the relaxed equilibrium conditions could be incorporated because it might be impossible to select the stress functions and parameters to fully satisfy both the equiribrium conditions and the suppression of kinematic deformation modes in the three-node curved beam hybrid-mixed formulation. Numerical examples confirm the superior and stable behavior of the proposed element regardless of slenderness ratio and curvature. Besides, the proposed element shows the outstanding performance in predicting the stress resultant distributions.

Finite Element Stress Analysis of Implant Prosthesis of Internal Connection System According to Position and Direction of Load (임플랜트-지대주의 내측연결 시스템에서 하중의 위치 및 경사에 따른 임플랜트 보철의 유한요소 응력분석)

  • Jang, Jong-Seok;Jeong, Yong-Tae;Chung, Chae-Heon
    • Journal of Dental Rehabilitation and Applied Science
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    • v.21 no.1
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    • pp.1-14
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    • 2005
  • The purpose of this study was to assess the loading distributing characteristics of implant prosthesis of internal connection system(ITI system) according to position and direction of load, under vertical and inclined loading using finite element analysis (FEA). The finite element model of a synOcta implant and a solid abutment with $8^{\circ}$ internal conical joint used by the ITI implant was constructed. The gold crown for mandibular first molar was made on solid abutment. Each three-dimensional finite element model was created with the physical properties of the implant and surrounding bone. This study simulated loads of 200N at the central fossa in a vertical direction (loading condition A), 200N at the outside point of the central fossa with resin filling into screw hole in a vertical direction (loading condition B), 200N at the centric cusp in a $15^{\circ}$ inward oblique direction (loading condition C), 200N at the in a $30^{\circ}$ inward oblique direction (loading condition D) or 200N at the centric cusp in a $30^{\circ}$ outward oblique direction (loading condition E) individually. Von Mises stresses were recorded and compared in the supporting bone, fixture, and abutment. The following results have been made based on this study: 1. Stresses were concentrated mainly at the ridge crest around implant under both vertical and oblique loading but stresses in the cancellous bone were low under both vertical and oblique loading. 2. Bending moments resulting from non-axial loading of dental implants caused stress concentrations on cortical bone. The magnitude of the stress was greater with the oblique loading than with the vertical loading. 3. An offset of the vertical occlusal force in the buccolingual direction relative to the implant axis gave rise to increased bending of the implant. So, the relative positions of the resultant line of force from occlusal contact and the center of rotation seems to be more important. 4. In this internal conical joint, vertical and oblique loads were resisted mainly by the implant-abutment joint at the screw level and by the implant collar. Conclusively, It seems to be more important that how long the distance is from center of rotation of the implant itself to the resultant line of force from occlusal contact (leverage). In a morse taper implant, vertical and oblique loads are resisted mainly by the implant-abutment joint at the screw level and by the implant collar. This type of implant-abutment connection can also distribute forces deeper within the implant and shield the retention screw from excessive loading. Lateral forces are transmitted directly to the walls of the implant and the implant abutment mating bevels, providing greater resistance to interface opening.

Fabrication of Nb SQUID on an Ultra-sensitive Cantilever (Nb SQUID가 탑재된 초고감도 캔티레버 제작)

  • Kim, Yun-Won;Lee, Soon-Gul;Choi, Jae-Hyuk
    • Progress in Superconductivity
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    • v.11 no.1
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    • pp.36-41
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    • 2009
  • Superconducting quantum phenomena are getting attention from the field of metrology area. Following its first successful application of Josephson effect to voltage standard, piconewton force standard was suggested as a candidate for the next application of superconducting quantum effects in metrology. It is predicted that a micron-sized superconducting Nb ring in a strong magnetic field gradient generates a quantized force of the order of sub-piconewtons. In this work, we studied the design and fabrication of Nb superconducting quantum interference device (SQUID) on an ultra-thin silicon cantilever. The Nb SQUID and electrodes were structured on a silicon-on-insulator (SOI) wafer by dc magnetron sputtering and lift-off lithography. Using the resulting SOI wafer, we fabricated V-shaped and parallel-beam cantilevers, each with a $30-{\mu}m$-wide paddle; the length, width, and thickness of each cantilever arm were typically $440{\mu}m,\;4.5{\mu}m$, and $0.34{\mu}m$, respectively. However, the cantilevers underwent bending, a technical difficulty commonly encountered during the fabrication of electrical circuits on ultra-soft mechanical substrates. In order to circumvent this difficulty, we controlled the Ar pressure during Nb sputtering to minimize the intrinsic stress in the Nb film and studied the effect of residual stress on the resultant device.

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