• 제목/요약/키워드: pressure sensitive

검색결과 793건 처리시간 0.028초

역문제를 이용한 음향장내의 소음해석 (The Analysis of Noise using of Inverse Problem in Acoustic Field)

  • 박성완
    • 한국생산제조학회지
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    • 제8권3호
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    • pp.66-75
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    • 1999
  • This paper is concerned with a analysis of noise by inverse problem available for analyzing the two and three-dimensional acoustic field problems. The noise of analysis considered in this study can be reduced to an optimum problem to find the optimal set of parameters defining the vibrating state of noise source surfaces. The optimal set of parameters are searched by the standard optimization procedure minimizing the square sum of the residuals between the measured and computed quantities of sound pressure at some points in the acoustic field. Computation is carried out for typical examples in which the noise sources are located on the infinite plane. It is demonstrated that the noise of analysis can be effectively made by using the sensitive reference data.

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Interfacial instability of Boger fluid in the pull-off test between two circular plates

  • Kang Hyoung Mi;Kim Chongyoup
    • Korea-Australia Rheology Journal
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    • 제16권4호
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    • pp.219-226
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    • 2004
  • In this study the deformation of liquid-air interface of Newtonian or Boger fluids filled between two par­allel-plates geometry was investigated when two surfaces were separated at a constant speed. The interface between the fluid and air showed either stable or unstable deformation depending on experimental con­ditions. Repeated experiments for a wide range of experimental conditions revealed that the deformation mode could be classified into three types: 'stable region', 'fingering' and 'cavitation'. The experimental condition for the mode of deformation was plotted in a capillary number vs. Deborah number phase plane. It has been found that the elasticity of Boger fluids destabilize the interface deformation. On the other hand, the elasticity suppresses the formation and growth of cavities.

Large deflection analysis of point supported super-elliptical plates

  • Altekin, Murat
    • Structural Engineering and Mechanics
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    • 제51권2호
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    • pp.333-347
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    • 2014
  • Nonlinear bending of super-elliptical plates of uniform thickness under uniform transverse pressure was investigated by the Ritz method. The material was assumed to be homogeneous and isotropic. The contribution of the boundary conditions at the point supports was introduced by the Lagrange multipliers. The solution was obtained by the Newton-Raphson method. The influence of the location of the point supports on the central deflection was highlighted by sensitivity analysis. An approximate relationship between the central deflection and the super-elliptical power was obtained using the method of least squares. The critical points where the maximum deflection may develop, and the influence of nonlinearity were highlighted. The nonlinearity was found to be sensitive to the aspect ratio. The accuracy of the algorithm was validated by comparing the central deflection with the solutions of elliptical and rectangular plates.

상어표피 모사 리블렛 구조의 탄성유체윤활 해석 (Elasto-hydrodynamic Lubrication Analysis for Biomimetic Riblet Surface like Shark Skin)

  • 김태완
    • 동력기계공학회지
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    • 제18권1호
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    • pp.128-134
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    • 2014
  • For the characteristic assessment of biomimetic shark skin structure pattern for engineering applications, we conducted the elastic hydrodynamic lubrication analysis for the shark skin surface pattern. The shark skin surfaces with roughness are generated numerically in the similar size with real shark skin scales. For the spherical contact on the generated shark skin surface with two different flow directions which are transversal and longitudinal, 3-dimensional elasto-hydrodynamic lubraction analysis are carried out. The result of the longitudinal flow which are similar with the flow of shark skin shows more beneficial effects with lower pressure and less sensitive effect with surface roughness.

사출압축성형을 통한 광디스크 기판 성형 및 복굴절의 측정 (Measurement of Birefringence Distribution in Optical Disk Substrates Fabricated by Injection-Compression Molding)

  • 김종성
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1999년도 춘계학술대회논문집
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    • pp.218-224
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    • 1999
  • It is necessary to improve mechanical and optical properties in the optical disk substrates as the information storage devices with high storage density using short wavelength laser are being developed. Injection compression molding is regarded as the most suitable process to manufacture optical disk substrates with high is regarded as the most suitable process to manufacture optical disk substrates with high dimensional accuracy low residual stresses and superb optical properties In the present study polycarbonate optical disk substrates were fabricated by injection compression molding and the birefringence regarded as one of the most important optical properties for optical disk is measured. The effects of various processing conditions upon the development of birefringence distribution were examined experimentally. It was found that the value of the birefringence distribution were very sensitive to the mold wall temperature history and the variance of the birefringence distribution in the radial direction was affected by the level of the packing and the compression pressure.

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The influence of atomosphere on high temperature crystal growth

  • Klimm, D.;Schroder, W.
    • 한국결정성장학회지
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    • 제9권4호
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    • pp.360-364
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    • 1999
  • The growth of crystals with high melting point$t_{fus}$$\geq$$1600^{\circ}C$ faces the researcher with experimental problems, as the choice of materials that withstand such high t is rather limited. Many metallic construction materials are in this high t range already molten or exhibit at least a drastically reduced mechanical strength. The very few materials with$t_{fus}$$1600^{\circ}C$ as e.g. W, Mo, and partially even Ir are more or less sensitive against oxygen upon heating. Whenever possible, high t crystal growth is performed under inert atmosphere (noble gases). Unfortunately, many oxides are not thermodynamically stable under such conditions, as reduction takes place within such atmosphere. A thoroughly search for suitable growth conditions has to be performed, that are on the one side "oxidative enough" to keep the oxides stable and on the other side "reductive enough" to avoid destruction of constructive parts of the crystal growth assembly. The relevant parameters are t and the oxygen partial pressure${po}_{2}$. The paper discusses quantitatively relevant properties of interesting oxides and construction materials and wasy to forecast theri behavior under growth conditions.

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축류송풍기의 삼차원 유동장 해석 (Three-dimensional analysis of the flow through an axial-flow fan)

  • 김광용;김정엽;정덕수
    • 대한기계학회논문집B
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    • 제21권4호
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    • pp.541-550
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    • 1997
  • Computational and experimental investigations on the three-dimensional flowfield through an automotive cooling fan are carried out in this work. Steady, incompressible, three-dimensional, turbulent flow through a rotating axial-flow fan is analyzed with Reynolds averaged Navier-Stokes equations and standard k-.epsilon. turbulence model. The governing equations are discretized with finite-volume approximations in non-orthogonal curvilinear coordinates. Computational static pressures on the casing wall agree well with the experimental data which are measured in this work. And, they are sensitive to the change of tip clearance. The flowfield is not significantly affected by the thickness of the blade. The k-.omega. model gives the static pressure rise on the casing wall which is similar to that with the k-.epsilon. model.

한미 FTA 협상전략의 특징 및 시사점 : 기간통신서비스 외자규제 사례를 중심으로 (Main Features and Implications of KORUS FTA Negotiation Strategy : The Case of Foreign Ownership Regulation on Facilities-based Public Telecom Services)

  • 이한영
    • 통상정보연구
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    • 제9권2호
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    • pp.399-422
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    • 2007
  • Like in other trade negotiations covering comprehensive sectors, it is reported that KOREA-US FTA tried so-called 'package deal' at the last minutes, when telecom services sector was positioned at the forefront and expected to partly play a role in buffering US' market-opening pressure on other sectors. Before everything else, Korean negotiators had to enhance the value of foreign ownership deregulation in telecom services sector as a leverage in the course of KOREA-US FTA negotiations. In addition, since foreign ownership change, if any, is highly sensitive issue either politically or policy-wise, it seems very difficult to find a breakthrough. Focusing on foreign ownership regulation in telecom services sector, this paper seeks how Korea has developed its strategic reasoning for negotiations and evaluates the outcomes of KOREA-US FTA negotiations.

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Immunohistochemical Changes of Apoptotic Control Genes by Chronic Inhibition of Nitric Oxide in Rats

  • Bae, Hyung-Joon
    • 대한의생명과학회지
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    • 제18권4호
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    • pp.420-427
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    • 2012
  • Sprague-Dawley (SD) rats were orally administered with NG-nitro-L-arginine methyl ester (L-NAME), which inhibits or blocks the production of nitric oxide from L-arginine in vascular endothelial cells and vessel tissue. We examined the effects of nitric oxide on some physiological changes such as blood pressure and heart rate, and confirms the apoptosis induced by the suppressed nitric oxide activity in the kidney. This study was performed to investigate correlation between the activities of nitric oxide and apoptosis by immunohistochemical changes of apoptotic control proteins with regulated chronic inhibition of nitric oxide. In the kidney from L-NAME-treated group, immunohistochemical reaction to the antigens of apoptosis inhibiting proteins such as bcl-2 and bcl-xL, exhibited a time-dependent reduction. The expression of apoptosis-inhibiting proteins such as bax and p53 increased expression in proportion to the duration of treatment. The most sensitive apoptosis regulating proteins to L-NAME were p53 in stimulation and bcl-2 in inhibition, respectively.

선박외벽용 작업을 위한 연마장비 힘제어 (Force Control of Robotic Vacuum Sweeping Machine for Shipment)

  • 진태석
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2013년도 춘계학술대회
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    • pp.509-512
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    • 2013
  • 본 논문은 산업용 로봇을 위한 힘 피드백 제어는 사람의 감각을 기반으로 한 작업을 대체하여 구현하기에 적합한 연마 시스템을 제안하였다. 기존 연마작업의 표면 연마, 비드처리, 기계 가공 디버링 등의 공정은 그 복잡성에서 자동화가 가장 곤란하다고 인식되어 주로 인력에 의존 해왔다. 본 연구는 연마 공구를 파지시킨 힘 제어 로봇에 의한 자동 연마 시스템의 구축을 위한 다축로봇 기반의 힘 센서로부터 신호 피드백 제어 방식의 특성을 파악하고 연마 공정에 적응성을 검증했다.

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