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.

Magnetic-field induced gap and staggered susceptibility in the S = 1/2 chain [PM?Cu(NO3)2?(H2O)2]n (PM = pyrimidine)

Abstract: Single-crystal magnetic susceptibility and specific heat studies of the one-dimensional copper complex [PMCu(NO3)2(H2O)2]n (PM = pyrimidine) show that it behaves like a uniform S = 1/2 antiferromagnetic Heisenberg chain, characterized by the exchange parameter J/kB = 36 K. Specific heat measurements in the applied magnetic field, however, reveal the formation of a field-induced spin excitation gap, whose magnitude depends on the magnitude and direction of the field. This behaviour is inconsistent with the ideal S = 1/2 Heisenberg chain. In the low-temperature region, a contribution to the susceptibility, approximately proportional to 1/T, is observed which varies strongly with the varying direction of the magnetic field. The field-induced gap and the 1/T contribution are largest for the same field direction. Previous observations of a field-induced gap in the related compounds copper benzoate and Yb4As3 have been explained by the alternating g tensor and alternating Dzyaloshinkii-Moriya interaction, producing an effective staggered magnetic field at the Cu and Yb ions. We apply this model to [PMCu(NO3)2(H2O)2]n and obtain a consistent quantitative explanation of the low-temperature susceptibility, the field-induced gap and their dependence on the magnetic-field direction.

Nonlinear optical generation using electromagnetically induced transparency in atomic hydrogen.

Abstract: Nonlinear optical generation using electromagnetically induced transparency is demonstrated with atomic hydrogen as a test medium. With the application of a strong-coupling laser field to the 3p-2s transition, the resonant Lyman-β (3p-1s) transition becomes transparent. The generated-sum-frequency Lyman-β radiation at 103 nm can continue to grow without suffering resonant absorption and phase mismatching

Interactive textbook and interactive Venn diagram: natural and intuitive interfaces on augmented desk system

Abstract: This paper describes two interface prototypes which we have developed on our augmented desk interface system, EnhancedDesk. The first application is Interactive Textbook, which is aimed at providing an effective learning environment. When a student opens a page which describes experiments or simulations, Interactive Textbook automatically retrieves digital contents from its database and projects them onto the desk. Interactive Textbook also allows the student hands-on ability to interact with the digital contents. The second application is the Interactive Venn Diagram, which is aimed at supporting effective information retrieval. Instead of keywords, the system uses real objects such as books or CDs as keys for retrieval. The system projects a circle around each book; data corresponding the book are then retrieved and projected inside the circle. By moving two or more circles so that the circles intersect each other, the user can compose a Venn diagram interactively on the desk. We also describe the new technologies introduced in EnhancedDesk which enable us to implement these applications.