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81.
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83.
Hawking radiation is studied for arbitrary scalars, fermions and spin-1 bosons, using a tunneling approach, to every order in ? but ignoring back-reaction effects. It is shown that the additional quantum terms yield no new contribution to the Hawking temperature. Indeed, it is found that the limit of small ? in the standard quantum WKB approximation is replaced by the near-horizon limit in the gravitational WKB approach. 相似文献
84.
EDOT‐diketopyrrolopyrrole copolymers for high bulk hole mobility and near infrared absorption
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Christian J. Mueller Chetan R. Singh Mukundan Thelakkat 《Journal of Polymer Science.Polymer Physics》2016,54(6):639-648
To obtain novel low‐bandgap materials with tailored hole‐transport properties and extended absorption, electron rich 3,4‐ethylenedioxythiophene is introduced as a comonomer in diketopyrrolo[3,4‐c]pyrrole copolymers with different aryl flanking units. The polymers are characterized by absorption and photoluminescence spectroscopy, dynamic scanning calorimetry, cyclic voltammetry, and X‐ray diffraction. The charge transport properties of these new materials are studied carefully using an organic field effect transistor geometry where the charge carriers are transported over a narrow channel at the semiconductor/dielectric interface. These results are compared to bulk charge carrier mobilities using space‐charge limited current (SCLC) measurements, in which the charge carrier is transported through the complete film thickness of several hundred nanometers. Finally, charge carrier mobilities are correlated with the electronic structure of the compounds. We find that in particular the thiophene‐flanked copolymer PDPP[T]2‐EDOT is a very promising candidate for organic photovoltaics, showing an absorption response in the near infrared region with an optical bandgap of 1.15 eV and a very high bulk hole mobility of 2.9 × 10?4 cm2 V?1 s?1 as measured by SCLC. This value is two orders of magnitudes higher than SCLC mobilities reported for other polydiketopyrrolopyrroles and is in the range of the well‐known hole transporting polymer poly(3‐hexylthiophene). © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 639–648 相似文献
85.
86.
Bernd Brügmann 《General Relativity and Gravitation》2009,41(9):2131-2151
The success of the moving puncture method for the numerical simulation of black hole systems can be partially explained by
the properties of stationary solutions of the 1 + log coordinate condition. We compute stationary 1 + log slices of the Schwarzschild
spacetime in isotropic coordinates in order to investigate the coordinate singularity that the numerical methods have to handle
at the puncture. We present an alternative integration method to obtain isotropic coordinates that simplifies numerical integration
and that gives direct access to a local expansion in the isotropic radius near the puncture. Numerical results have shown
that certain quantities are well approximated by a function linear in the isotropic radius near the puncture, while here we
show that in some cases the isotropic radius appears with an exponent that is close to but unequal to one.
This paper is dedicated to the memory of Jürgen Ehlers. I have known JE for a number of years, in particular during his time
as founding director of the Albert Einstein Institute in Potsdam. JE was the mentor of my habilitation thesis in 1996, and
I am deeply thankful for many insightful discussions. JE combined great breadth and physical intuition with sharp analytical
thought. His example inspired me to look beyond the numerical methods and results of numerical relativity to the analytic
foundations. For example, while at the AEI, S. Brandt and I introduced “puncture initial data” for the numerical construction
of general multiple black hole spacetimes [3]. While the puncture construction starts with an analytic trick of the sort that
numerical relativists may devise, it is fair to say that the keen interest in analytical relativity created by JE at the AEI
induced us to push our analysis one step further. As a result [3] connects to [26] for an existence and uniqueness proof for
such black hole initial data, using weighted Sobolev spaces (see also [4–6]). The present work and its predecessors [9–12]
represent an example where numerical experiments led to the discovery of an analytic solution for the 1 + log gauge for the
Schwarzschild solution, and the present result, although modest, is of the type which I believe JE would have appreciated. 相似文献
87.
Barun Majumder 《Physics letters. [Part B]》2011,701(4):384-387
Recently Ali et al. (2009) [13] proposed a Generalized Uncertainty Principle (or GUP) with a linear term in momentum (accompanied by Planck length). Inspired by this idea we examine the Wheeler-DeWitt equation for a Schwarzschild black hole with a modified Heisenberg algebra which has a linear term in momentum. We found that the leading contribution to mass comes from the square root of the quantum number n which coincides with Bekenstein?s proposal. We also found that the mass of the black hole is directly proportional to the quantum number n when quantum gravity effects are taken into consideration via the modified uncertainty relation but it reduces the value of mass for a particular value of the quantum number. 相似文献
88.
Extending Parikh and Wilczek's work to the non-stationary black hole, we study the Hawking radiation of the non-stationary Kerr black hole by the Hamilto-Jacobi method. The result shows that the radiation spectrum is not purely thermal and the tunnelling probability is related to the change of Bekenstein Hawking entropy, which gives a correction to the Hawking thermal radiation of the black hole. 相似文献
89.
Structure and Photoelectric Characteristics of Functional Polymers and of Compositions Based on Them 总被引:1,自引:0,他引:1
The electronic processes in disordered organic solids were analyzed, classified, and summarized. They include the photogeneration of charge pairs, electron transport, geminal and bimolecular recombination, and the capture of charge carriers in local electronic states. General criteria were formulated for the targeted search for and the creation of new prospective polymers and their compositions with organic pigments and related compounds having specific photoelectric characteristics for electrographic and holographic media, photoelectric converters, and electroluminescent and photorefractive devices. 相似文献
90.
Hawking radiation can be viewed as a process of quantum tunneling near the black hole horizon. When a particle with angular
momentum L ≠ ωa tunnels across the event horizon of Kerr or Kerr-Newman black hole, the angular momentum per unit mass a should be changed. The emission rate of the massless particles under this general case is calculated, and the result is consistent
with an underlying unitary theory.
Supported by the National Natural Science Foundation of China (Grant No. 10773002) and the National Basic Research Program
of China (Grant No. 2003CB716302) 相似文献