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111.
112.
113.
RF superconducting (SRF) cavities can work in continuous wave mode or long pulse mode.SRF technology has been developing rapidly since the end of the last century.RF superconducting technology is widely used in particle accelerators around the world.As the key elements, research on superconducting cavities is carried out worldwide.Besides Europe, the United States and Japan, many countries have already started SRF projects, such as Canada, India, Korea, etc.Great improvements on SRF technology have been made in China in recent years.Progress in SRF cavities is introduced in this paper. 相似文献
114.
Total reaction and fusion cross sections at sub- and near-barrier energies for the system 7Li + 28Si
A. Pakou K. Rusek N. Alamanos X. Aslanoglou M. Kokkoris A. Lagoyannis T. J. Mertzimekis A. Musumarra N. G. Nicolis D. Pierroutsakou D. Roubos 《The European Physical Journal A - Hadrons and Nuclei》2009,39(2):187-194
Fusion cross sections are extracted for the 7Li$ + $28Si system, via reaction cross section and transfer measurements at sub- and near-barrier energies ( E
lab = 5.7 to 14MeV). The energy evolution of transfer to reaction cross section ratios is determined with the aid of CDCC calculations,
which subsequently allows the deduction of fusion cross sections at sub- and near-barrier energies. It is shown that fusion
can be well represented in a BPM context. Fusion cross sections are compared for the systems 7Li$ + $28Si and 6Li$ + $28Si, the latter studied previously, and are found to exhibit different strengths. Last, the direct channels determined at 13MeV,
are found to be dominated by a 2n -transfer mechanism. 相似文献
115.
Utilizing the quantum statistical method and applying the new state density equation motivated by generalized uncertainty principle in quantum gravitaty, we avoid the difficulty in solving wave equation and directly calculate the partition function of bosonic and fermionic field on the background of rotating and charged black string. Then near the cosmological horizon, entropies of bosonic and fermionic field are calculated on the background of black string. When constant A introduced in generalized uncertainty principle takes a proper value, we derive Bekenstein- Hawking entropy and the correction value corresponding cosmologicaJ horizon on the background of rotating and charged black string. Because we use the new state density equation, in our calculation there are not divergent term and small mass approximation in the original brick-wall method. From the view of quantum statistic mechanics, the correction value to Bekenstein-Hawking entropy of the black string is derived. It makes people deeply understand the correction value to the entropy of the black string cosmological horizon in non-spherical coordinate spacetime. 相似文献
116.
Raj Bali 《International Journal of Theoretical Physics》2009,48(2):476-486
Bianchi Type V magnetized string dust bulk viscous fluid cosmological model with variable magnetic permeability, is investigated.
The magnetic field is due to an electric current produced along x-axis. Thus the magnetic fields is in yz-plane and F
23 is the only non-vanishing component of electromagnetic field tensor F
ij
. To get the deterministic model in terms of cosmic time t, we have also assumed the condition ζ
θ=constant where ζ the coefficient of bulk viscosity and θ the expansion in the model. The behaviour of the model in presence and absence of magnetic field and bulk viscosity and singularities
in the model are also discussed.
相似文献
117.
In this work the equation of circular loops of cosmic string possessing time-dependent tension is studied in the de Sitter
spacetime. We find that the cosmic string loops with initial radius r(t
0)>0.707L, L de Sitter radius, should not collapse to form a black hole. It is also found that in the case of r(t
0)<0.707L a loop of cosmic string whose tension depends on some power of cosmic time can not become a black hole if the power is lower
than a critical value which is associated with the initial size of the loop. Our research gives rise to some important corrections
to the conclusion in the case of loops of cosmic string with constant tension in the same background. 相似文献
118.
119.
Dumitru Vieru Corina Fetecau Muhammad Athar Constantin Fetecau 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2009,60(2):334-343
The unsteady flow of a viscoelastic fluid with the fractional Maxwell model, induced by a constantly accelerating plate between
two side walls perpendicular to the plate, is investigated by means of the integral transforms. Exact solutions for the velocity
field are presented under integral and series forms in terms of the derivatives of generalized Mittag–Leffler functions. The
corresponding solutions for Maxwell fluids are obtained as limiting cases for β → 1. In the absence of the side walls, all
solutions that have been determined reduce to those corresponding to the motion over an infinite plate.
相似文献
120.
Average-optimal string matching 总被引:2,自引:0,他引:2
The exact string matching problem is to find the occurrences of a pattern of length m from a text of length n symbols. We develop a novel and unorthodox filtering technique for this problem. Our method is based on transforming the problem into multiple matching of carefully chosen pattern subsequences. While this is seemingly more difficult than the original problem, we show that the idea leads to very simple algorithms that are optimal on average. We then show how our basic method can be used to solve multiple string matching as well as several approximate matching problems in average optimal time. The general method can be applied to many existing string matching algorithms. Our experimental results show that the algorithms perform very well in practice. 相似文献