Bilepton production in $ e^-\gamma $ collisions

We study the production of bileptons, new gauge bosons of lepton number two, in the minimal 3-3-1 model in high energy collisions. If the bilepton masses are in the range of 300 GeV the reaction will give observable cross-sections in future colliders.Received: 5 August 2003, Published online: 23 March 2004Dang Van Soa: On leave of absence from Department of Physics, Hanoi University of Education, Hanoi, VietnamHoang Ngoc Long: On leave of absence from Institute of Physics, NCST, P.O. Box 429, Bo Ho, Hanoi 10000, Vietnam     

Parametric dependence of turbulent particle transport in tore supra plasmas

Steady state full noninductive current tore supra plasmas offer a unique opportunity to study the local parametric dependence of particle pinch velocity, in order to discriminate among different theories. Magnetic field shear is found to generate an inward pinch which is dominant in the gradient region (normalized radius 0.3相似文献   

Renormalization-group improved calculation of top-quark production near threshold

The top-quark cross section close to threshold in e(+)e(-) annihilation is computed including the summation of logarithms of the velocity at next-to-next-to-leading-logarithmic order in QCD. The remaining theoretical uncertainty in the normalization of the total cross section is at the few-percent level, an order of magnitude smaller than in previous next-to-next-to-leading order calculations. This uncertainty is smaller than the effects of a light standard-model Higgs boson.     

Internal transport barrier with ion-cyclotron-resonance minority heating on tore supra

Recently, reversed magnetic shear operation was performed using only ion-cyclotron-resonance frequency minority heating (ICRH) during current ramp-up. A wide region of reversed magnetic shear has been obtained. For the first time, an electron internal transport barrier sustained by ICRH is observed, with a dramatical drop of density fluctuations. This barrier was maintained, on the current flat top, for about 2 s.     

Dispersion and Confinement Loss Control in Modified Hexagonal Photonic Crystal Fibers

This paper presents a novel technique for the control of chromatic dispersion and confinement loss in hexagonal photonic crystal fibers (H-PCFs). It is demonstrated that it is possible to obtain very low chromatic dispersion of 0 ± 0:38 ps/(nm·km) in the wavelength range of 1.41 to 1.66 μm and confinement loss of less than 0.0001 dB/km from a six ring modified H-PCF (MH-PCF). The higher order dispersion at 1.55 μm is about −0.001 ps/(nm²-km).     

Reduced graphene oxide-encapsulated mesoporous silica as sulfur host for lithium–sulfur battery

Journal of Solid State Electrochemistry - With up to fivefold higher in energy density vs. lithium-ion battery, lithium–sulfur (Li–S) battery is a compelling energy storage system,...     

Structural properties of graphs of diameter 2 with maximal repeats

It was shown using eigenvalue analysis by Erdös et al. that with the exception of C₄, there are no graphs of diameter 2, of maximum degree d and of order d², that is, one less than the Moore bound. These graphs belong to a class of regular graphs of diameter 2, and having certain interesting structural properties, which will be proved in this paper.     

TPR and XPS characterization of chromia–lanthana–zirconia catalyst prepared by impregnation and microwave plasma enhanced chemical vapour deposition methods

Chromia–lanthana–zirconia catalysts prepared by wet impregnation and microwave plasma enhanced chemical vapour deposition methods have been characterized by temperature-programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS). The impregnation procedure requires large amounts of solvent and calcination at high temperatures producing Cr⁶⁺ species. Unlike this, it is found that the microwave plasma enhanced chemical vapour deposition (PECVD) method predominantly produces Cr³⁺ species on zirconia-based supports. Moreover, it has been shown that the dispersion of chromium species deposited on zirconia-based support by the PECVD method is higher than the dispersion of those prepared by wet impregnation. Thus, the advantages of PECVD over the impregnation method consist in this case in preventing the use of large amounts of solvent and avoiding the primary formation of poisonous Cr⁶⁺ species as well as in enabling the deposition of chromium species with high dispersion on zirconia-based supports.