1,393 research outputs found
Photon-Assisted Quasiparticle Transport and Andreev Transport through an Interacting Quantum Dot
Resonant tunneling through a quantum dot coupled to superconducting
reservoirs in the presence of time-dependent external voltage has been studied.
A general formula of the current is derived based on the nonequilibrium Green's
function technique. Using this formula photon-assisted quasiparticle transport
has been investigated for the quantum dot connected to superconductors. In
addition, resonant Andreev transport through a strongly correlated quantum dot
connected to a normal metallic lead and a superconducting lead is studied.Comment: 9 pages(1 column) with 3 figure
Performance and Growth of Large Firms in China
This study examines the impacts of several factors, such as
internal capital markets, technology transfer via FDI, and
in-house R&D activities on the performance and growth of firms
using data gathered from the top 200 companies in China
during the period 1998-2003. A finance company, as an affiliate
in the business group, is used as proxy for the internal capital
market. The foreign joint venture firms and in-house research
center are used as proxies for technology transfer and for the
existence of in-house R&D activities, respectively. This paper
finds that having foreign joint ventures is positively correlated
with the firms growth but not with the financial and market
performance of firms. In contrast, doing in-house R&D activities
is positively correlated with the financial and market performances,
as well as the growth of firms
??????????????? ????????? ????????? ?????? ??? ????????????
??????????????? ????????? ???????????? ???????????? ?????? ?????????????????? ??????????????? ?????? ???????????? ??????. ??? ??????????????? ??????????????? ??? ?????? ????????? ???????????? ????????? ??????????????? ????????? ???????????????. ?????? ??????????????? ????????? ??? ?????? ????????? ???????????????, ??? ?????? ????????? diethylnitrosamine (DEN)??? C3H/HeN ?????? ?????? ?????? ???????????? ??? ?????? ????????? ????????? ???????????????. DEN?????? ????????? ???????????? ?????? alkaline phosphatase (ALP) ??????, TUNEL positive ???????????? ??????, ??? ???????????? ?????? ???????????? duct??? ??????, ?????????????????? ????????????, Masson???s trichrome ???????????? ????????? ???????????? ???, ?????? ?????? ?????? ??? ????????? ????????? ???????????? ?????? ???????????? ?????? ?????? ????????? ??? ?????????. ?????????, ??????????????? ?????? ???????????? ????????? ?????? ?????????????????? ??????, ?????? ?????? ??? ????????? ???????????? ??????????????? ???????????? ???????????? ???????????? ?????? ?????? ????????? ??? ?????????. ???????????? ???????????? ????????? ???????????? ??????, ???????????? ???????????? ???????????? ?????? ????????? ???, solvent partition ????????? ???????????? ????????? ???????????? hexane, ethyl acetate, water ???????????? ???????????????. ?????? ??????????????? ?????? ????????? ??????????????? ??????????????? ???, ethyl acetate ???????????? ??????????????? ????????? ?????????????????? ??????????????? ?????? ??????????????? ???????????? ????????? ????????? ????????? ??? ?????????. ????????? ethyl acetate???????????? ???????????? ????????? ????????? ??? ?????????, ??????????????? ????????? ??? ?????? ????????? ????????? ?????????. ???????????????, ??????????????? ????????? ????????????????????? ?????? ????????? ??? ?????? ????????? ???????????? ?????? ??????????????? ????????? ??? ?????? ????????? ????????? ????????? ?????? ???????????????. ?????????, ?????? ??????????????? ?????? ???????????? ?????? ??? ?????? ?????? ???????????? ??????????????? ?????? ????????? ????????? ??? ?????? ????????? ???????????? ??????.clos
Spin Fluctuation Induced Dephasing in a Mesoscopic Ring
We investigate the persistent current in a hybrid Aharonov-Bohm ring -
quantum dot system coupled to a reservoir which provides spin fluctuations. It
is shown that the spin exchange interaction between the quantum dot and the
reservoir induces dephasing in the absence of direct charge transfer. We
demonstrate an anomalous nature of this spin-fluctuation induced dephasing
which tends to enhance the persistent current. We explain our result in terms
of the separation of the spin from the charge degree of freedom. The nature of
the spin fluctuation induced dephasing is analyzed in detail.Comment: 4 pages, 4 figure
Effect of Charge Fluctuations on the Persistent Current through a Quantum Dot
We study coherent charge transfer between an Aharonov-Bohm ring and a
side-attached quantum dot. The charge fluctuation between the two
sub-structures is shown to give rise to algebraic suppression of the persistent
current circulating the ring as the size of the ring becomes relatively large.
The charge fluctuation at resonance provides transition between the diamagnetic
and the paramagnetic states.
Universal scaling, crossover behavior of the persistent current from a
continuous to a discrete energy limit in the ring is also discussed.Comment: 5 pages, 4 figure
Preparation of polylactide-co-glycolide nanoparticles incorporating celecoxib and their antitumor activity against brain tumor cells
Tae-Ho Kim1*, Young-Il Jeong2*, Shu-Guang Jin2, Jian Pei2, Tae-Young Jung1, Kyung-Sub Moon1, In-Young Kim1, Sam-Suk Kang1, Shin Jung1,21Department of Neurosurgery, 2Brain Tumor Research Laboratory, Chonnam National University Research Institute of Medical Science, Chonnam National University Hwasun Hospital and Medical School, Gwangju, Republic of Korea *These authors contributed equally to this work. Background: Celecoxib, a cyclo-oxygenase (COX)-2 inhibitor, has been reported to mediate growth inhibitory effects and to induce apoptosis in various cancer cell lines. In this study, we examined the potential effects of celecoxib on glioma cell proliferation, migration, and inhibition of COX-2 expression in vitro. Methods: Celecoxib was incorporated into poly DL-lactide-co-glycolide (PLGA) nanoparticles for antitumor drug delivery. Results: PLGA nanoparticles incorporating celecoxib had spherical shapes and their particle sizes were in the range of 50–200 nm. Drug-loading efficiency was not significantly changed according to the solvent used, except for acetone. Celecoxib was released from the PLGA nanoparticles for more than 2 days, and the higher the drug content, the longer the duration of drug release. PLGA nanoparticles incorporating celecoxib showed cytotoxicity against U87MG tumor cells similar to that of celecoxib administered alone. Furthermore, celecoxib did not affect the degree of migration of U87MG cells. PLGA nanoparticles incorporating celecoxib showed dose-dependent cytotoxicity similar to that of celecoxib alone in C6 rat glioma cells. Western blot assay of the C6 cells showed that neither celecoxib alone nor PLGA nanoparticles incorporating celecoxib affected COX-2 expression. Conclusion: PLGA nanoparticles incorporating celecoxib had antitumor activity similar to that of celecoxib alone, even though these particles did not affect the degree of migration or COX-2 expression in the tumor cells. Keywords: celecoxib, cyclo-oxygenase-2, PLGA nanoparticles, glioma, antitumor activit
Spin Fluctuation and Persistent Current in a Mesoscopic Ring Coupled to a Quantum Dot
We investigate the persistent current influenced by the spin fluctuations in
a mesoscopic ring weakly coupled to a quantum dot. It is shown that the Kondo
effect gives rise to some unusual features of the persistent current in the
limit where the charge transfer between two subsystems is suppressed. Various
aspects of the crossover from a delocalized to a localized dot limit are
discussed in relation with the effect of the coherent response of the Kondo
cloud to the Aharonov-Bohm flux.Comment: 4 pages, 2 figure
- …