共查询到20条相似文献,搜索用时 0 毫秒
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研究了Xe(6p[1/2]_0 )和Xe(6p[3/2]_2)激发态与含氧分子反应的淬灭动力学.在与N_2O和OCS分子反应中,观察到较强的XeO和XeS紫外发射,其最大强度分别在234nm和227nm,并对发射机构进行了讨论. 相似文献
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A. Donnachie H.G. Dosch M. Rueter 《The European Physical Journal C - Particles and Fields》2000,13(1):141-150
The total hadronic cross sections at high energy are calculated as a function of energy and photon virtuality in a model combining Reggeon exchange,
the quark box diagram (a fixed pole in Regge language) and soft and hard pomeron exchanges evaluated in the context of dipole-dipole
scattering. Good agreement is obtained with the data for the real cross section and for the real photon structure function . However the model prediction for the cross section is too small. This is attributed to an incorrect extrapolation of the dependence of the hard pomeron adopted here. Parametrising it independently shows that the hard part of the cross section
can be well represented by a simple Regge pole with intercept .
Received: 19 August 1999 / Published online: 3 February 2000 相似文献
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A. Schwabedissen D. Loffhagen Th. Hammer W. Bötticher 《Applied physics. B, Lasers and optics》1994,58(6):471-481
Absorption spectroscopic measurements of effective particle number densities of excited Xe, Ne, Cl, and H performed on a small scale discharge with well-defined current and voltage pulses are compared with the results of model calculations over a wide range of discharge parameters. The reaction kinetic pathways determining the ionization and dissociative attachment rates have been verified by the good agreement obtained during the quasi-steady-state phase of the discharge for Xe and H. To reproduce the rise times of the excited Xe particle number densities during the ignition phase, the electron collision excitation cross sections of ground state Xe published by Puech and Mizzi [1] had to be enhanced by about 25%. From the Ne measurements it is concluded that the electron collision excitation cross sections of ground state Ne published by Puech and Mizzi [1] may be too large near the threshold. Measurements of excited Cl particle number densities are unsuitable to check the attachment kinetics of HCl, because these densities are mainly determined by reactions not involving the formation of Cl– ions. 相似文献
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A steady-state, chemiluminescence technique has been used to measure effective rate constants for vibrational relaxation as a function of vibrational level for KrF* in collisions with He, Ne, and Ar and XeCl* with Ar. The effective rate constants reported include contributions to relaxation due to intersystem crossing between theB andC states, in addition to direct relaxation within theB state. The relevance of these results to the understanding of previous measurements in KrF and XeCl lasers is discussed. 相似文献
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研究了在Xe(6p)激发态与N_2O和OCS反应中,产物XeO~*和XeS~*的紫外荧光特性.实验证实它们具有短的寿命以及发射谱在高压Ar中的振动弛豫效应. 相似文献
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E. Gotsman E. Levin U. Maor E. Naftali 《The European Physical Journal C - Particles and Fields》2000,14(3):511-523
We extend our previous treatment of the p cross section based on Gribov's hypothesis to the case of photon–photon scattering. With the aid of two parameters, determined
from the experimental data, we separate the interactions into two categories corresponding to short (“soft”) and long (“hard”)
distance processes. The photon–photon cross section thus receives contributions from three sectors, soft–soft, hard–hard and
hard–soft. The additive quark model is used to describe the soft–soft sector, pQCD the hard–hard sector, while the hard–soft
sector is determined by relating it to the system. We calculate and display the behaviour of the total photon–photon cross section and its various components and polarizations
for different values of energy and virtuality of the two photons, and discuss the significance of our results.
Received: 12 January 2000 / Published online: 6 April 2000 相似文献
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The positive column of low pressure DC glow discharges in Xe/Cl2 and Kr/Cl2 gas mixtures has been investigated with respect to its UV radiation power and radiative efficiency for a wide range of parameters (total gas pressure: 1–30 mbar, current 10–30 mA, partial pressure of Cl2: 1–33%). Also the radial distribution of the particle number densities of XeCl* (B) and KrCl* (B) has been determined by absolutely calibrated emission spectroscopy. Optimum UV (190–350 nm) output and efficiency has been found in gas mixtures with a relative Cl2 partial pressure of 2–3% and total gas pressure of 12–18 mbar. At these parameters, the UV radiation power per column length is greater than 40 Watt/m with a radiative efficiency of 15–18%. These discharges could be used for UV induced photochemical processes. 相似文献
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In the first part of the paper we introduce a new parametrization for the manifold underlying quadratic analogue of the usual Heisenberg group introduced in Accardi et al. (Infin Dimens Anal Quantum Probab Relat Top 13:551–587, 2010) which makes the composition law much more transparent. In the second part of the paper the new coordinates are used to construct an inductive system of \(*\)-algebras each of which is isomorphic to a finite tensor product of copies of the one-mode quadratic Weyl algebra. We prove that the inductive limit \(*\)-algebra is factorizable and has a natural localization given by a family of \(*\)-sub-algebras each of which is localized on a bounded Borel subset of \(\mathbb {R}\). Moreover, we prove that the family of quadratic analogues of the Fock states, defined on the inductive family of \(*\)-algebras, is projective hence it defines a unique state on the limit \(*\)-algebra. Finally we complete this \(*\)-algebra under the (minimal regular) \(C^*\)-norm thus obtaining a \(C^*\)-algebra. 相似文献
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Taking into account the experimental accuracy of the body motions in the solar system, we propose a General Relativity Theory
which is new but nevertheless completely metric.
*Presented at the IARD 2004 Conference, Saas-Fee Switzerland. 相似文献
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Ashwani Kumar Singh Amir Iqbal Upendra Bahadur Singh Roman S. Dabrowski 《Phase Transitions》2018,91(8):811-820
Thermodynamic and electro-optical characterization of a ferroelectric liquid crystalline material, namely ((S) (+) 4-(1-methylheptyloxy) phenyl 4′-octyloxybiphenyl-4-carboxylate) possessing paraelectric SmA*, ferroelectric SmC*, hexatic SmBh* and SmI* phases has been carried out. Phase identification has been done by optical and thermodynamic studies. Switching parameters viz. spontaneous polarization, switching time and rotational viscosity have been determined. The spontaneous polarization has been found to increase with decreasing temperature in SmC* phase. The switching time is found of the order of few milliseconds. 相似文献
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The structure of the B s1(5830) meson has not yet been exactly known in the quark model. In this paper, the strong form factors and coupling constants of B s1, as a conventional meson, are investigated. The coupling constants $ g_{B_{s1} B^* K} $ and $ g_{B_{s1} B^* K_0^* } $ are calculated in the framework of the three-point QCD sum rules. Our findings are compared with the results of the light-cone sum rules (LCSR) and heavy-chiral unitary approaches. 相似文献