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Scalar dark matter interpretation of the DAMPE data with U(1) gauge interactions
Cao, Junjie,Feng, Lei,Guo, Xiaofei,Shang, Liangliang,Wang, Fei,Wu, Peiwen American Physical Society 2018 Physical review. D Vol.97 No.9
<P>Recently, the Dark Matter Particle Explorer (DAMPE) experiment released the new measurement of the total cosmic e(+) e(-) flux between 25 GeV and 4.6 TeV, which indicates a spectral softening at around 0.9 TeV and a tentative peak at around 1.4 TeV. We utilize a scalar dark matter (DM) model to explain the DAMPE peak by XX -> Z'Z' -> l (l) over barl'(l) over bar 'l with an additional anomaly-free gauged U (l) family symmetry, in which X, Z'and l((')) denote, respectively, the scalar DM, the new gauge boson, and l((')) = e, mu, tau, with m(x) similar to m(z)' similar to 2 x 1.5 (TeV). We first illustrate that the minimal framework Gsm X U(l)(Y') with the above mass choices can explain the DAMPE excess, which, however, be excluded by LHC constraints from the Z' searches. Then, we study a nonminimal framework G(SM) X U(l)(Y') x U(i)(Y') in which U(l)(Y') mixes with U(l)(Y'). We show that such a framework can interpret the DAMPE data and at the same time survive all other constraints including the DM relic abundance, DM direct detection, and collider bounds. We also investigate the predicted e(+) e(-) spectrum in this framework and find that the mass splitting Delta m = m(x) - m(z') should be less than about 17 GeV to produce the peaklike structure.</P>
Dynamic response of a base-isolated CRLSS with baffle
Xuansheng Cheng,Bo Liu,Liangliang Cao,Dongpo Yu,Huan Feng 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.66 No.3
Although a rubber isolation cushion can reduce the dynamic response of a structure itself, it has little influence on the height of a sloshing wave and even may induce magnification action. Vertical baffles are set into a base-isolated Concrete Rectangular Liquid Storage Structure (CRLSS), and baffles are opened as holes to increase the energy dissipation of the damping. Problems of liquid nonlinear motion caused by baffles are described using the Navier-Stokes equation, and the space model of CRLSS is established considering the Fluid-Solid Interaction (FSI) based on the Finite Element Method (FEM). The dynamic response of an isolated CRLSS with various baffles under an earthquake is analyzed, and the results are compared. The results show that when the baffle number is certain, the greater the number of holes in baffles, the worse the damping effects; when a single baffle with holes is set in juxtaposition and double baffles with holes are formed, although some of the dynamic response will slightly increase, the wallboard strain and the height of the sloshing wave evidently decrease. A configuration with fewer holes in the baffles and a greater number of baffles is more helpful to prevent the occurrence of two failure modes: wallboard leakage and excessive sloshing height.
Dynamic response of a base-isolated CRLSS with baffle
Cheng, Xuansheng,Liu, Bo,Cao, Liangliang,Yu, Dongpo,Feng, Huan Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.66 No.3
Although a rubber isolation cushion can reduce the dynamic response of a structure itself, it has little influence on the height of a sloshing wave and even may induce magnification action. Vertical baffles are set into a base-isolated Concrete Rectangular Liquid Storage Structure (CRLSS), and baffles are opened as holes to increase the energy dissipation of the damping. Problems of liquid nonlinear motion caused by baffles are described using the Navier-Stokes equation, and the space model of CRLSS is established considering the Fluid-Solid Interaction (FSI) based on the Finite Element Method (FEM). The dynamic response of an isolated CRLSS with various baffles under an earthquake is analyzed, and the results are compared. The results show that when the baffle number is certain, the greater the number of holes in baffles, the worse the damping effects; when a single baffle with holes is set in juxtaposition and double baffles with holes are formed, although some of the dynamic response will slightly increase, the wallboard strain and the height of the sloshing wave evidently decrease. A configuration with fewer holes in the baffles and a greater number of baffles is more helpful to prevent the occurrence of two failure modes: wallboard leakage and excessive sloshing height.
Temperature characteristics of indentation rolling resistance of belt conveyor
Lidong Zhou,Zengfa Wu,Yongchao Li,Huiqiang Yao,Yuan Liu,Yuan Yuan,Wenjun Meng,Liangliang Han,Xueqin Cao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.8
In order to study the influence of temperature on the indentation rolling resistance of belt conveyor, theoretical analysis, numerical simulation analysis and experimental study of conveyor belt indentation rolling resistance with temperature characteristics were carried out in this paper, and the influence rules of different factors on the indentation rolling resistance of belt conveyor were obtained. First, the three-component Maxwell model is chosen as the viscoelastic model for the conveyor belt rubber material, and the viscoelastic modulus function based on temperature effects is constructed from the DMA experimental data fitting. Second, we introduce the one-dimensional Winkler foundation model to derive a mathematical expression for the indentation rolling resistance based on temperature properties. Then, a mathematical model of the indentation rolling resistance of a conveyor belt with temperature characteristics is developed in MATLAB and numerical simulations are performed. Finally, using the existing experimental equipment to conduct experiments, the experimental results are compared with the numerical simulation result. The results show that the theoretical numerical simulation results of the indentation rolling resistance with temperature effect presented in this paper have a consistent change trend with the experimental results; at constant temperature and constant load, the indentation rolling resistance increases with increasing band velocity; at constant temperature and constant velocity, the indentation rolling resistance increases with increasing load; at constant load and speed, when the temperature is lower than 0 °C or higher than 25 °C, the rolling resistance increases with the increase of temperature, when the temperature is between 0 °C and 25 °C, the rolling resistance decreases gradually with the increase of temperature.