Search

The statistical properties of the spatial derivatives of the Stokes parameters for polarization speckle are investigated theoretically and experimentally. Based on the Gaussian assumption, the six-dimensional joint probability density function (p.d.f) for the derivatives of the Stokes parameters ( S 1 , S 2 , and S 3 ) are all derived analytically for the first time. Subsequently, three two-dimensional p.d.f of derivatives for each Stokes parameters and the corresponding six marginal p.d.f are also given. Based on polar-interferometry, experiments have also been conducted to demonstrate the validity of the principle.

Plastic strain of structures having stress concentration is estimated by using the simplified method or the finite element elastic solutions. As the simplified methods used in codes and standards, we can cite Neuber’s formula and elastic follow-up procedure. Also we will cite stress redistribution locus (abbreviated as SRL) method recently proposed as the other simplified method. In the present paper, inelastic finite element analysis of perforated plate, whose stress concentration is about 2.2∼2.5, is carried out, and stress and strain locus in inelastic range by the detailed finite element solutions is investigated to compare accuracy of the simplified methods. As strain-controlled loading conditions, monotonic loading, cyclic loading and cyclic loading having hold time in tension are assumed. The inelastic strain affects significantly life evaluation of fatigue and creep-fatigue, and the stress and strain locus is discussed from the detailed inelastic finite element solutions.Copyright © 2010 by ASME

In analogy with the degree of polarization used widely for the description of partially polarized thermal light, we introduced a new concept of the spatial degree of polarization to characterize the statistical properties of the polarization speckle with its polarization states fluctuating in space. As a function of the spatial degree of polarization, the first order statistics of the polarization speckle are studied theoretically, and the corresponding probability density functions of the Stokes parameters are measured experimentally by a polarization interferometer to demonstrate the validity of the principle.

エネルギー消費量の算定法としては従来, RMR法が用いられてきたが, 近年, 携帯用24時間心拍数記憶装置が開発されたことにより, 心拍数を用いるエネルギー消費量算定方法が試みられている。その一方法としてHR-VO2法がある。そこでリンゴ栽培従事者を対象とし, 勢定, 摘花, 摘果, 袋かけおよび収穫に従事した1労働日の24時間心拍数記録をもとに, エネルギー消費量をHR-VO2法で推定し, 一部についてはRMR法と比較してHR-VO2法の有用性を検討した。24時間心拍記録からみた作業中の心拍数水準は, 摘花, 摘果, 袋かけ等では90～100拍, 収穫でも110拍前後にとどまっており, Rodahlの作業強度分類では“moderate work”のレベルに該当した。また, 同じ作業でも, 午前に比べて午後の心拍水準が低下する傾向を示し, 心拍数の日周期リズムとは異なる挙動を示した。HR-VO2法で算定した各労働日のエネルギー消費量は, RMR法による報告値と比べほぼ妥当な値と思われた。収穫作業日の一例について, HR-VO2法とRMR法による消費エネルギー量を比較すると, 前者は2,654kcalで後者より376kcal (16.5%) 高かった。作業動作別エネルギー消費量について, 両者の相関関係をみるとr=0.987 (p 袋かけ≒摘花>摘果>剪定の順序であった。収穫は日本人の栄養所要量で示された生活活動強度IV (重い) に該当し, 春季農繁期の管理作業日は同じ強度III (やや高い) に該当した。したがって, HR-VO2法によるエネルギー消費量推定法は, 若干の問題点はあるものの, 生体の代謝水準を比較的正確に反映する方法であり, その簡便性と相まって, 今後, RMR法に代わって導入されることが望ましいと考えられる。

A new technique for fluid mechanics measurement is proposed that makes use of pseudophase singularities in an analytic signal representation of a speckle-like pattern generated by a Laguerre-Gauss filter operation. Based on the formal analogy between the polarization of the vector wave and the gradient field for the complex analytic signal, a set of Stokes-like parameters have been applied for the description of the anisotropic core structure of the pseudophase singularities, which serves as unique fingerprints attached to the seeding particles moving with the flow. Experimental results for flow velocity and acceleration measurement are presented that demonstrate the validity of the proposed optical vortex metrology for fluid mechanics measurement.

Over the past decades, optical vortices or phase singularities have come to attract more and more attentions in the fields of applications such as optical metrology and photon manipulation. Recently, we proposed a new technique of micro-displacement measurement, called Optical Vortex Metrology (OVM) [1, 2]. The key idea of this technique is to make use of the phasesingularities in the pseudophase information of the complex analytic signal obtained from partial Hilbert transform, Riesz transform or Laguerre-Gauss transform of speckle patterns. Although we have experimentally demonstrated the validity of the proposed OVM in displacement measurement with both large dynamic range and high spatial resolution, the application of the proposed technique was restricted because the distortions of the morphology for the phase singularities stemming from speckle decorrelation enhance the difficulty in the unique search and identification of the registered marker phase singularity for calculation of their coordinate difference. In this paper, we propose a new technique that substantially improves the OVM technique in its ability of uniquely identifying the matching phase singularities under large distortions. In addition to the information about the location and the core structures of the phase singularities, we also detect the spatial structures of a group of the pseudophase singularities. This spatial structure can serve as a “constellation” that uniquely characterizes the mutual position relation between the individual phase singularities, and can be used for the purpose of the unique identification of a cluster of the phase singularities. Experimental results have been demonstrated that support the proposed principle.

The ordering of the one-dimensional Heisenberg spin glass interacting via the long-range power-law interaction is studied by Monte Carlo simulations. Particular attention is paid to the possible occurrence of the ``spin-chirality decoupling'' for appropriate values of the power-law exponent \sigma. Our result suggests that, for intermediate values of $\sigma$, the chiral-glass order occurs at finite temperatures while the standard spin-glass order occurs only at zero temperature., Comment: Proceedings of the Highly Frustrated Magnetism (HFM2006) conference. To appear in a special issue of J. Phys. Condens. Matter

A rate-type constitutive equation of compressible isotropic hyperelasticity and a finite element formulation based on the Updated Lagrangian approach are proposed. The constitutive equations of compressible hyperelasticity are simplified by introducing modified tensors in an intermediate configuration, which separates the volumetric deformation from the distortional deformation. Selective integration and a mixed pressure/displacement formulation have been adopted to avoid volumetric locking and the hourglass modes. The deformation of a simple rectangle block was simulated to show the effect of the choice of the finite elements and the integration methods on the stability and the accuracy of proposed method. Moreover, loading tests were carried out on a prototype specimen of a vibration control device made from circumferential rubber parts and reinforcing steel layers in order to evaluate applicability of the proposed formulation to such devices.

This paper proposes a new numerical model of lead material to predict mechanical properties of isolation and vibration control devices using lead as damping material. Shear and tensile loading tests of lead were carried out to make the numerical model. Shear loading test specimen were constructed from a circumferential lead part welded at the top and bottom to steel flanges. Cyclic stress-strain relations in large strain region were obtained from shear loading test results. The elastic constants and the initial yield stress were given from tensile loading test results. Therefore a numerical model was made using both shear loading and tensile loading test results. Mechanical properties of lead dampers and isolated rubber bearings were simulated using the proposed numerical model via finite element method to show applicability of the model.Copyright © 2003 by ASME

A highly-reliable ferroelectric memory (FeRAM) which ensures retention of data written at a low voltage of 2.5 V and humidity resistance for 10 years under a high temperature of 70/spl deg/C has been successfully developed for the first time. These excellent characteristics have been attained by a newly developed ferroelectric material with mixed superlattice crystal of Y-1 family and a integration technology which makes the use of pl-SiN passivation possible.