Electron transport in a ferromagnet-superconductor junction on graphene

In a usual ferromagnet connected with a superconductor, the exchange potential suppresses the superconducting pairing correlation. We show that this common knowledge does not hold in a ferromagnetsuperconductor junction on a graphene. When the chemical potential of a graphene is close to the conical point of energy dispersion, the exchange potential rather assists the charge transport through a junction interface. The loose-bottomed electric structure causes this unusual effec

Microwave band on-chip coil technique for single electron spin resonance in a quantum dot

Microwave band on-chip microcoils are developed for the application to single electron spin resonance measurement with a single quantum dot. Basic properties such as characteristic impedance and electromagnetic field distribution are examined for various coil designs by means of experiment and simulation. The combined setup operates relevantly in the experiment at dilution temperature. The frequency responses of the return loss and Coulomb blockade current are examined. Capacitive coupling between a coil and a quantum dot causes photon assisted tunneling, whose signal can greatly overlap the electron spin resonance signal. To suppress the photon assisted tunneling effect, a technique for compensating for the microwave electric field is developed. Good performance of this technique is confirmed from measurement of Coulomb blockade oscillations.Comment: 7 pages, 8 figures, Accepted for publication in Rev. Sci. Instrum. The bibliography file is update

Thick polymer blend organic solar cells fabricated by slow drying

AbstractOrganic solar cells (OSCs) were generally fabricated by two types of deposition method, namely, dry and wet. Many OSCs use very thin films that cannot fully absorb light. Thick film deposition for OSCs has numerous benefits, such as highly efficient harnessing of solar light and low leakage. Thick film fabrication for polymer blend organic solar cells by the wet deposition method was investigated. OSCs were fabricated by spin coating and slow drying using P3HT and bis[60]PCBM in a solvent, respectively. Two-dimensional (2D)-mapping images of the photocurrent of the cells were measured by a laser-beam-induced current method. A low-current density area was not found in all the cells. As a result, we succeeded in fabricating OSCs with a power conversion efficiency of more than 4% by slow drying

Competitive Pressure from Neighboring Markets and Optimal Privatization Policy

We formulate a mixed oligopoly model in which one state-owned public enterprise competes with n private firms in the same market and m private firms in the neighboring market. We investigate how n and m affect the optimal degree of privatization. We find a nonmonotone (monotone) relationship between the optimal degree of privatization and the number of private competitors in the neighboring (same) market. The optimal degree of privatization is increasing in the number of private firms in the same market, and the relationship between the optimal degree of privatization and the number of private competitors in the neighboring market is an inverted U-shape. An increase in m more likely increases the optimal degree of privatization when the degree of product differentiation is low. Our results suggest that more competitive pressure from competitors supplying differentiated products can reduce the optimal degree of privatization

The transformation of the Japanese commercial code and its impact on the Japanese economy

Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management, 2007.Includes bibliographical references (leaves 96-100).The legal system is an essential basis of the society and economy of every country, and it changes continually in accordance with national social and economic situations. The Japanese Commercial Code is no exception. One of the most significant and fundamental Japanese laws, it was enacted in 1899 as part of the modernization of Japanese society as the country moved away from a policy of seclusion followed by the old feudal government. The new Code was strongly affected by corporate laws in place at the time in Germany and France. However, as the balance of power in the world economy changed over the ensuing years, the Japanese Commercial Code and other corporate laws were influenced by American laws, and the nature of the Commercial Code was slowly transformed, especially following the Second World War and after the collapse of the so-called "bubble economy" in Japan. In this thesis, I discuss the history of fundamental Japanese laws, the steps and players in the legislative process, and present details about the introduction of the share exchange system, which stimulated many more mergers and acquisitions in Japan. Then I analyze the economic impact of new legal procedures for M&As, including the share exchange system, and identify possible directions for Japanese corporate laws in the future.by Toshihiro Yoshida.M.B.A