Nagoya Institute of Technology

About: Nagoya Institute of Technology is a education organization based out in Nagoya, Japan. It is known for research contribution in the topics: Thin film & Catalysis. The organization has 10766 authors who have published 19140 publications receiving 255696 citations. The organization is also known as: Nagoya Kōgyō Daigaku & Nitech.

Enhanced fluorescence from Eu3+ owing to surface plasma oscillation of silver particles in glass

Abstract: We describe the increase of europium ion (Eu3+) fluorescence owing to resonant plasma oscillation of silver (Ag) particles in silica (SiO2) glass, which were precipitated by annealing in a reducing atmosphere sol–gel derived SiO2 glass containing Ag+ and Eu3+ ions. Nanometer size effects of Ag particles on the increase were also investigated as a function of the reduction time. The mean particle size and the volume fraction of silver particles in glass were estimated from absorption spectra using the Mie–Drude theory modified by the electron mean free path model. The fluorescence from Eu3+ ions when the excitation was a N2 laser increased in the presence of silver particles of ∼4.3 nm size. From comparison of the radiative damping time of the plasma oscillation with the lifetime of Eu3+ fluorescence we, tentatively, concluded that the induced surface plasma oscillation by incidence and the interaction between Eu3+ and Ag particles occurred simultaneously.

Two‐photon processes in defect formation by excimer lasers in synthetic silica glass

Abstract: Defect formation in dehydrated silica glasses was investigated using various excimer lasers with different energies. The ArF laser (6.4 eV) generates the E’ center more effectively than the KrF laser (5.0 eV), while the XeCl laser (4.0 eV) generated no centers. Defect generation was found to be proportional to the square of the laser photon density, indicating that it occurs dominantly due to a two‐photon process which makes band‐to‐band excitation possible. The E’ center probably originated from oxygen‐deficient centers. Contributions to the E’ center formation from a process involving direct absorption at the sites of intrinsic defects in SiO2 glass were discussed on the basis of the excitation energy dependence and a comparison with the effect of a low‐pressure mercury lamp.

Trainable ISTA for Sparse Signal Recovery

Abstract: In this paper, we propose a novel sparse signal recovery algorithm called the trainable iterative soft thresholding algorithm (TISTA). The proposed algorithm consists of two estimation units: a linear estimation unit and a minimum mean squared error (MMSE) estimator based shrinkage unit. The error variance required in the MMSE shrinkage unit is precisely estimated from a tentative estimate of the original signal. The remarkable feature of the proposed scheme is that TISTA includes adjustable variables that control step size and the error variance for the MMSE shrinkage function. The variables are adjusted by standard deep learning techniques. The number of trainable variables of TISTA is nearly equal to the number of iteration rounds and is much smaller than that of known learnable sparse signal recovery algorithms. This feature leads to highly stable and fast training processes of TISTA. Computer experiments show that TISTA is applicable to various classes of sensing matrices, such as Gaussian matrices, binary matrices, and matrices with large condition numbers. Numerical results also demonstrate that, in many cases, TISTA provides significantly faster convergence than approximate message passing (AMP) and the learned iterative shrinkage thresholding algorithm and also outperforms orthogonal AMP in the NMSE performance.