511 keV line and diffuse gamma rays from moduli

We obtain the spectrum of gamma ray emissions from the moduli whose decay into $e^+ e^-$ accounts for the 511 keV line observed by SPI/INTERGRAL. The moduli emit gamma rays through internal bremsstrahlung, and also decay directly into two gammas via tree and/or one-loop diagrams. We show that the internal bremsstahlung constrains the mass of the moduli below $\sim 40$ MeV model-independently. On the other hand, the flux of two gammas directly decayed from the moduli through one loop diagrams will exceed the observed galactic diffuse gamma-ray background if the moduli mass exceeds $\sim 20$ MeV in the typical situation. Moreover, forthcoming analysis of SPI data in the range of 1-8 MeV may detect the line emisson with the energy half the moduli mass in the near future, which confirms the decaying moduli scenario.Comment: 6 pages, 5 figures, published versio

Roles of Exogenous Technologies in Vehicle Innovation: Cases from a Japan’s Automotive Parts Manufacturing Firm

This paper explores the roles of technological innovations in the growth of Japan’s motor vehicle industry, mainly from technology spillover perspective from the early 2000s to today. An empirical analysis focusing on business performances, R&D investments, and patent applications taking a noteworthy unique case in Japan was attempted. Empirical analyses on the productivity of patent to technology stock, use of exogenous technologies for their own technological innovation on its Automotive Business Unit elucidated that innovation capabilities, incorporation of exogenous technologies, and profit generation makes a virtuous cycle of continuous technological innovation. Furthermore, we found that the range of technology spillovers is not only expanding along with the development of information communication technology but also superposing itself intricately between organizational (industry– firm–business unit) layers

Product Architecture as a Coordination System (Japanese)

Baldwin and Clark (2000) brought the substantial attention to the concept of product architecture. This concept, particularly the concept of module architecture, defines a product system as a "coordination system," taking the viewpoint that a product system is an object that is used by human users or developed by human developers. In this paper, product architecture is defined as a design concept for a product system that calls for complex part-to-part coordination in order to fulfill the user's objectives, whereby we seek to show that module architecture can clarify (1) the functions of a product, and (2) the relationship between users' commands and corresponding product actions. By doing so, it becomes possible for human users or developers, whose actions and behaviors are instinctively "context dependent," to operate and use highly complex systems as well as to design and develop new systems by seeking an appropriate combination of division of labor and collaboration between human beings and product systems.

Internal Degradation Monitoring of Power Devices During Power Cycling Test

A technique to monitor internal degradation to failure of power devices in real time was proposed. Required components for this technique are (1) non-destructive inside imaging, (2) power stress control and (3) device cooling. We constructed the system with scanning acoustic tomography (SAT), DC power supply controlled by own made program and water cooling system, respectively. In the case of a TO-3P packaged MOSFET, propagation of internal degradations to failure was successfully recorded as time series data by using this system. At the present time, the system is modified for high power and large size IGBT modules.8th International Conference on Integrated Power Electronics Systems (CIPS 2014), February 25-27, 2014, Nuremberg, German

Investor Sentiment in Japanese and U.S. Daily Mutual Fund Flows

We find evidence that is consistent with the hypothesis that daily mutual fund flows may be instruments for investor sentiment about the stock market. We use this finding to construct a new index of investor sentiment, and validate this index using data from both the United States and Japan. In both markets exposure to this factor is priced, and in the Japanese case, we document evidence of negative correlations between Bull' and Bear' domestic funds. The flows to bear foreign funds in Japan display some evidence of negative correlation to domestic and foreign equity funds, suggesting that there is a foreign vs. domestic sentiment factor in Japan that does not appear in the contemporaneous U.S. data. By contrast, U.S. mutual fund investors appear to regard domestic and foreign equity mutual funds as economic substitutes.

Lasing from a single quantum wire

A laser with an active volume consisting of only a single quantum wire in the 1-dimensional (1-D) ground state is demonstrated. The single wire is formed quantum-mechanically at the T-intersection of a 14 nm Al_{0.07}Ga_{0.93}As quantum well and a 6 nm GaAs quantum well, and is embedded in a 1-D single-mode optical waveguide. We observe single-mode lasing from the quantum wire ground state by optical pumping. The laser operates from 5 to 60 K, and has a low threshold pumping power of 5 mW at 5 K.Comment: 4 pages including 4 figure