University of Electro-Communications

About: University of Electro-Communications is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Laser & Robot. The organization has 8041 authors who have published 16950 publications receiving 235832 citations. The organization is also known as: UEC & Denki-Tsūshin Daigaku.

Lu2O3:Yb3+ ceramics – a novel gain material for high-power solid-state lasers

Abstract: We have developed Yb3+:Lu2O3 ceramics with nanocrystalline technology and a vacuum sintering method. A laser diode end-pumped efficient Yb3+:Lu2O3 ceramic laser was demonstrated. A 0.7 W cw output power was obtained with the slope efficiency of ≈36% at 1035 nm wavelength, and 0.95 W with the slope efficiency of ≈53% at 1079 nm. We classify the Lu2O3:Yb3+ ceramics as gain medium for high-power solid-state lasers (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Nonuniversal Efimov atom-dimer resonances in a three-component mixture of 6Li.

Abstract: We observed an enhanced atom-dimer loss due to the existence of Efimov states in a three-component mixture of $^{6}\mathrm{Li}$ atoms. We measured the magnetic-field dependence of the atom-dimer loss in the mixture of atoms in state $|1⟩$ and dimers formed in states $|2⟩$ and $|3⟩$, and found two peaks corresponding to the degeneracy points of the energy levels of $|23⟩$ dimers and the ground and first excited Efimov trimers. We found that the locations of these peaks disagree with universal theory predictions, in a way that cannot be explained by nonuniversal two-body properties. We constructed theoretical models that characterize the nonuniversal three-body physics of three-component $^{6}\mathrm{Li}$ atoms in the low-energy domain.

Phase retrieval based on the irradiance transport equation and the Fourier transform method: experiments

Abstract: Experimental demonstrations of deterministic phase retrieval based on the Teague-Streibl irradiance transport equation are presented. A new technique is proposed, in which the transport equation is solved by the Fourier transform method for a periodic boundary condition with high spatial carrier frequency, which is created by making a light beam with unknown phase distribution pass through a grating. Quantitative phase measurements were performed by experiments without recourse to interferometry, and the results were found to be in good agreement with theory.

Microhardness and fracture toughness of Y2O3-and Y3Al5O12-based nanocrystalline laser ceramics

Abstract: The microhardness and fracture toughness of laser nanocrystalline ceramics based on the cubic oxides Y2O3 and Y3Al5O12 are determined experimentally. It is shown by comparative measurements that the fracture toughness and microhardness of Y2O3 ceramics exceed the corresponding parameters of Y2O3 single crystals by factors of 2.5 and 1.3, respectively. The fine morphology of grains and grain boundaries in fractures is investigated. It is ascertained that changes in the mechanical properties of the nanocrystalline ceramics under study are related to both the sizes and structure of grains and the structure of grain boundaries. It is suggested that twinning processes determine the mechanisms of formation of nanocrystalline ceramics.

Analysis of warranty claim data: a literature review

Abstract: Purpose – To provide a brief survey of the literature directed towards the analysis of warranty claim data.Design/methodology/approach – For convenience, this survey of the analysis of warranty claims data is somewhat arbitrarily be classified by topics as follows: age‐based claims analysis, aggregated warranty claims analysis, marginal counts of claims analysis, warranty claims analysis by using covariates, estimation of lifetime distribution using supplementary data, two‐dimensional warranty, warranty costs analysis, sales lag and reporting lag analysis, and forecasts of warranty claims.Findings – Emphasis is placed on a discussion of different kinds of warranty claims data selected from reviews and on a comparison of the statistical models and methods used to analyze such data.Research limitations/implications – Since the literature on product warranty data is vast, more work on this problem is needed.Practical implications – This review points out why warranty claims data is important and gives a surv...