Gauged Q ball in a piecewise parabolic potential

Q ball solutions are considered within the theory of a complex scalar field with a gauged U(1) symmetry and a parabolic-type potential. In the thin-walled limit, we show explicitly that there is a maximum size for these objects because of the repulsive Coulomb force. The size of Q ball will increase with the decrease of local minimum of the potential. And when the two minima degenerate, the energy stored within the surface of the Q ball becomes significant. Furthermore, we find an analytic expression for gauged Q ball, which is beyond the conventional thin-walled limit.Comment: 1 figure

On the Quintessence with Abelian and Non-abelian Symmetry

We study the perturbations on both "radial" and "angular" components of the quintessence with an internal abelian and non-abelian symmetry. The properties of the perturbation on the "radial" component depend on the specific potential of the model and is similiar for both abelian and non-abelian case. We show that the consine-type potential is very interesting for the O(\textit{N}) quintessence model and also give a critical condition of instability for the potential. While the properties of perturbations on "angular" components depend on whether the internal symmetry is abelian or non-abelian, which we have discussed respectively. In the non-abelian case, the fluctuation of the "angular" component will increase rapidly with time while in the abelian case it will not.Comment: 15 pages, to be published in Int. J. Mod. Phys.

Quasinormal modes of stringy black holes

String theory is a promising candidate for a fundamental quantum theory of all interactions including Einstein gravity. Some solutions in string theory can be interpreted as black holes. Using the semi-analytic method and WKB method,the quasinormal modes(QNMs)of 1+1 dimensional black hole in string theory are studied.The QNMs of 1+3 dimensional black hole in string theory are also calculated through numerical approach.The numerical investigation has shown that the late time gravitational oscillation of the black hole under an external perturbaton is dominated by certain QNMs.Comment: 2 figure

Challenges and Prospects of Vehicle OTA Spherical Near-Field Measurement Probes

This Paper Discusses the Issue of Measuring Probe Indicators for Large-Scale Equipment, Such as Automobiles, under Conditions of Offset Configuration. a Simulation of Spherical Near-Field Measurement based on an Offset Configuration is Presented in This Paper. the Measurement Error is Defined According to the Reference Data Calculated by Spherical Wave Expansion Theory. through Comparative Analysis of the Simulation Results, the Main Reason for the Measurement Error is the Insufficient Coverage of the Probe\u27s Beamwidth. by Adjusting the Probe\u27s Radiation Pattern using Simulation Software, an Optimized Probe that Satisfies Near-Field Measurement Requirements under Meter-Level Offset Conditions is Obtained. Finally, based on the Simulation Results, a Set of Recommended Values for the Main Performance of the Optimized Probe is Provided

A Research on Community-Based Livestock of Qinghai-Tibet Plateau

Qinghai-Tibet Plateau locates in Southwestern China, covering the whole area of Tibet Autonomous Region, Qinghai Province, Southern part of Gansu Province, Northwestern part of Sichuan Province and Northwestern part of Yunnan Province, with an area of around 139.08 million hectares of natural grassland, accounting for 39% of the total area of natural grassland in China. It is also the largest natural ecozones in China and one of the least disturbed regions by human activities, with its air, water sources, soil, grassland, wildlife in their pristine state. Qinghai-Tibet Plateau is the native home for Tibetan people. Grassland animal husbandry is the foundation of the economy of QTP and the main source of livelihood for local nomadic people. During the long term of concerted evolution with the nature, Tibetan people living on Qinghai-Tibet Plateau have formed a uniquely holistic grassland ecological culture that is compatible with their production system and the ecosystem. The majority of Tibetan people observe Tibetan Buddhism. Their respect for nature and their belief in that all sentient beings are equal take deep root in their traditional culture. Their harmonious co-existence with nature exemplifies the eco-civilization ideas and provides a solid cultural foundation for both ecology conservation and featured animal husbandry development. On Qinghai-Tibet Plateau, national policies and initiatives such as dual contract of livestock and forage, natural grassland vegetation recovery, returning grazing land to grassland, grassland ecosystem subsidy and rewarding mechanism have been implemented, playing an important role in promoting grassland ecosystem conservation and grassland animal husbandry development. However, since grassland animal husbandry is a complex system involving grassland, farm animal, environment, society, economy, culture, etc, there are still many outstanding problems to be solved