10,594 research outputs found
PDMS/PVA composite ferroelectret for improved energy harvesting performance
This paper address the PDMS ferroelectret discharge issue for improved long- term energy harvesting performance. The PDMS/PVA ferroelectret is fabricated using a 3D-printed plastic mould technology and a functional PVA composite layer is introduced. The PDMS/PVA composite ferroelectret achieved 80% piezoelectric coefficient d33 remaining, compared with 40% without the proposed layer over 72 hours. Further, the retained percentage of output voltage is about 73% over 72 hours
Periodicities in Solar Coronal Mass Ejections
Mid-term quasi-periodicities in solar coronal mass ejections (CMEs) during
the most recent solar maximum cycle 23 are reported here for the first time
using the four-year data (February 5, 1999 to February 10, 2003) of the Large
Angle Spectrometric Coronagraph (LASCO) onboard the Solar and Heliospheric
Observatory (SOHO). In parallel, mid-term quasi-periodicities in solar X-ray
flares (class >M5.0) from the Geosynchronous Operational Environment Satellites
(GOES) and in daily averages of Ap index for geomagnetic disturbances from the
World Data Center (WDC) at the International Association for Geomagnetism and
Aeronomy (IAGA) are also examined for the same four-year time span. Several
conceptual aspects of possible equatorially trapped Rossby-type waves at and
beneath the solar photosphere are discussed.Comment: Accepted by MNRAS, 6 figure
In situ growth of blue-emitting thin films of cerium-doped barium chloride hydrate at low temperatures
Blue emission was observed from thin films of barium chloride hydrate doped with cerium. The films were deposited by spray pyrolysis of aqueous solutions with substrate temperatures between 250 and 450°C. The cathodoluminescence (CL) spectrum consists of two peaks at 443 and 485 nm due to 4f-5d transitions of cerium ion. The dependence of the emission band on deposition temperature and Ce/Ba ratio is discussed. The CL luminance and luminous efficiency at 5 kV were 120 cd/mÂČ and 0.48 lm/W, respectively, for the films deposited at temperatures as low as 250°C. The results indicate barium chloride hydrate doped with cerium is a blue phosphor that exhibits relatively efficient luminescence after processing at low temperatures. © 2003 American Institute of Physics.published_or_final_versio
An Information Model for Geographic Greedy Forwarding in Wireless Ad-Hoc Sensor Networks
In wireless ad-hoc sensor networks, an important issue often faced in geographic greedy forwarding routing is the "local minimum phenomenon" which is caused by deployment holes and blocks the forwarding process. In this paper, we provide a new information model for the geographic greedy forwarding routing that only forwards the packet within the so-called request zone. Under this new information model, the hole and its affected area are identified easily and quickly in an unsafe area with a labeling process. The greedy forwarding will be blocked if and only if a node inside the unsafe area is used. Due to the shape of the request zone, an unsafe area can be estimated as a rectangular region in the local view of unsafe nodes. With such estimate information, the new routing method proposed in this paper will avoid blocking by holes and achieve better performance in routing time while the cost of information construction is greatly reduced compared with the best results known to date.Department of ComputingRefereed conference pape
Enhanced superconductivity at the interface of W/SrRuO point contact
Differential resistance measurements are conducted for point contacts (PCs)
between tungsten tip approaching along the axis direction and the
plane of SrRuO single crystal. Three key features are found.
Firstly, within 0.2 mV there is a dome like conductance enhancement due to
Andreev reflection at the normal-superconducting interface. By pushing the W
tip further, the conductance enhancement increases from 3\% to more than 20\%,
much larger than that was previously reported, probably due to the pressure
exerted by the tip. Secondly, there are also superconducting like features at
bias higher than 0.2 mV which persists up to 6.2 K, resembling the enhanced
superconductivity under uniaxial pressure for bulk SrRuO crystals
but more pronounced here. Third, the logarithmic background can be fitted with
the Altshuler-Aronov theory of tunneling into quasi two dimensional electron
system, consistent with the highly anisotropic electronic system in
SrRuO.Comment: prb style, 9 pages, 8 fig
New variable separation approach: application to nonlinear diffusion equations
The concept of the derivative-dependent functional separable solution, as a
generalization to the functional separable solution, is proposed. As an
application, it is used to discuss the generalized nonlinear diffusion
equations based on the generalized conditional symmetry approach. As a
consequence, a complete list of canonical forms for such equations which admit
the derivative-dependent functional separable solutions is obtained and some
exact solutions to the resulting equations are described.Comment: 19 pages, 2 fig
Distinct versus overlapping functions of MDC1 and 53BP1 in DNA damage response and tumorigenesis
The importance of the DNA damage response (DDR) pathway in development, genomic stability, and tumor suppression is well recognized. Although 53BP1 and MDC1 have been recently identified as critical upstream mediators in the cellular response to DNA double-strand breaks, their relative hierarchy in the ataxia telangiectasia mutated (ATM) signaling cascade remains controversial. To investigate the divergent and potentially overlapping functions of MDC1 and 53BP1 in the ATM response pathway, we generated mice deficient for both genes. Unexpectedly, the loss of both MDC1 and 53BP1 neither significantly increases the severity of defects in DDR nor increases tumor incidence compared with the loss of MDC1 alone. We additionally show that MDC1 regulates 53BP1 foci formation and phosphorylation in response to DNA damage. These results suggest that MDC1 functions as an upstream regulator of 53BP1 in the DDR pathway and in tumor suppression. © 2008 Minter-Dykhouse et al. The Rockefeller University Press.published_or_final_versio
KIAA1967 (KIAA1967)
Review on KIAA1967 (KIAA1967), with data on DNA, on the protein encoded, and where the gene is implicated
Approximate perturbed direct homotopy reduction method: infinite series reductions to two perturbed mKdV equations
An approximate perturbed direct homotopy reduction method is proposed and
applied to two perturbed modified Korteweg-de Vries (mKdV) equations with
fourth order dispersion and second order dissipation. The similarity reduction
equations are derived to arbitrary orders. The method is valid not only for
single soliton solution but also for the Painlev\'e II waves and periodic waves
expressed by Jacobi elliptic functions for both fourth order dispersion and
second order dissipation. The method is valid also for strong perturbations.Comment: 8 pages, 1 figur
Loops in Twistor Space
We elucidate the one-loop twistor-space structure corresponding to
momentum-space MHV diagrams. We also discuss the infrared divergences, and
argue that only a limited set of MHV diagrams contain them. We show how to
introduce a twistor-space regulator corresponding to dimensional regularization
for the infrared-divergent diagrams. We also evaluate explicitly the
`holomorphic anomaly' pointed out by Cachazo, Svrcek, and Witten, and use the
result to define modified differential operators which can be used to probe the
twistor-space structure of one-loop amplitudes.Comment: 21 pages, TeX. v3. missing citations added. v4. subtlety with the i
\epsilon prescription clarifie
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