9,364 research outputs found
Two-dimensional heterogeneous photonic bandedge laser
We proposed and realized a two-dimensional (2D) photonic bandedge laser
surrounded by the photonic bandgap. The heterogeneous photonic crystal
structure consists of two triangular lattices of the same lattice constant with
different air hole radii. The photonic crystal laser was realized by
room-temperature optical pumping of air-bridge slabs of InGaAsP quantum wells
emitting at 1.55 micrometer. The lasing mode was identified from its spectral
positions and polarization directions. A low threshold incident pump power of
0.24mW was achieved. The measured characteristics of the photonic crystal
lasers closely agree with the results of real space and Fourier space
calculations based on the finite-difference time-domain method.Comment: 14 pages, 4 figure
Does Earnings Management Amplify The Association Between Corporate Governance And Firm Performance?: Evidence From Korea
This paper aims to examine whether earnings management strengthens the causal links between corporate governance and firm performance. It examines the association between corporate governance and real activity-based earnings management and extends it to firm performance. This study involves 1,104 listings on the Korean Stock Exchange and finds that real activity-based earnings management decreases if firms have a well-established governance system, and such earnings management could strengthen the causal link between corporate governance and firm performance as measured by Tobin’s Q. Our study results are the first empirical evidences that real activity-based earnings management is effectively controlled by a corporate governance system and that it has links between corporate governance and performance. This provides the importance of corporate governance which could effectively constrain real activity-based earnings management, such that eventually influences the firm’s performance. In particular, it provides useful insights into corporate structures in which ownership is highly concentrated. Our findings are of great importance for Korea, in which the predominant business structure for large enterprises is that of the chaebol (equivalent to the Japanese keiretsu), which consists of conglomerates of many smaller companies and in which the structure of corporate governance is that of owner control
Monoclinic and Correlated Metal Phase in VO_2 as Evidence of the Mott Transition: Coherent Phonon Analysis
In femtosecond pump-probe measurements, the appearance of coherent phonon
oscillations at 4.5 THz and 6.0 THz indicating the rutile metal phase of VO_2
does not occur simultaneously with the first-order metal-insulator transition
(MIT) near 68^oC. The monoclinic and correlated metal(MCM) phase between the
MIT and the structural phase transition (SPT) is generated by a photo-assisted
hole excitation which is evidence of the Mott transition. The SPT between the
MCM phase and the rutile metal phase occurs due to subsequent Joule heating.
The MCM phase can be regarded as an intermediate non-equilibrium state.Comment: 4 pages, 2 figure
Jamming Effect Analysis of Two Chinese GNSS BeiDou-II Civil Signals
Threats of electronic warfare, especially to global positioning systems (GPSs), have been rapidly increasing. The development of the Chinese navigation satellite system BeiDou has been extended to a global navigation satellite system (GNSS). In December 2011, the Chinese government released a specification document—a test version of a civil BeiDou-II signal called B1(I). A strong possibility exists that BeiDou-II (Chinese GNSS) will be adopted by North Korea in the near future. Therefore, research on BeiDou-II is essential. Since BeiDou-II is a newly-built system, few jamming effect analyses of its positioning signals have been performed. Thus, in this study, we analyze quality factors (Q) and the tolerable jamming signal power among two BeiDou-II civil signals, and two GPS civil signals, in three jamming conditions: band-limited white noise (BLWN), matched spectrum (MS), and continuous wave (CW). In addition, we present each jamming propagation range.DOI:http://dx.doi.org/10.11591/ijece.v2i6.181
Synthesis of VO_2 Nanowire and Observation of the Metal-Insulator Transition
We have fabricated crystalline nanowires of VO_2 using a new synthetic
method. A nanowire synthesized at 650^oC shows the semiconducting behavior and
a nanowire at 670^oC exhibits the first-order metal-insulator transition which
is not the one-dimensional property. The temperature coefficient of resistance
in the semiconducting nanowire is 7.06 %/K at 300 K, which is higher than that
of commercial bolometer.Comment: 3 pages, 4 figures, This was presented in NANOMAT 2006 "International
workshop on nanostructed materials" on June 21-23th of 2006 in Antalya/TURKE
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