| 1. |
- Li, Bo, et al.
(författare)
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Wind tunnel test study on influence of open/close operation on aerodynamic noise characteristics of high-speed pantographs
- 2024
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Ingår i: Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology). - 1672-7207. ; 55:5, s. 1846-1854
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Tidskriftsartikel (refereegranskat)abstract
- Wind tunnel tests of aerodynamic noise at wind speeds from 160 km/h to 324 km/h were carried out for high speed pantograph developed by Beijing CRRC CED Co. Ltd. The effects of wind speed and open/close operation status on pantograph aerodynamic noise characteristics were analyzed, and the pantograph aerodynamic noise at higher speed was predicted. The results show that the aerodynamic noise of the pantograph and its propagation characteristics are closely related to the wind speed and operating status. The panhead and nearby areas are prone to single-tone noise due to the influence of shedding vortices. The total sound pressure energy of the far-field noise increases with the power of 5.6 − 6.0 of wind speed. The total sound pressure levels of the pantograph far-field noise in the open/closed state are predicted to be about 106.8 dB and 106.6 dB respectively at the wind speed of 400 km/h by data fitting.
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| 2. |
- Deng, Qihong, et al.
(författare)
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Source Apportionment and Chemical composition of particulate matter (PM10) in university classrooms
- 2009
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Ingår i: Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology). - 1672-7207. ; 40:2, s. 332-328
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Tidskriftsartikel (refereegranskat)abstract
- The inhalable particulate matter (PM10) was continuously monitored and sampled in the classrooms of Central South University at Changsha by Tapered Element Oscillating Microbalance 1400a (TEOM 1400a) from September to December, 2007. The chemical compositions of the PM10 samples were analyzed by the X-ray fluorescence (XRF), and then the source apportionment of the classroom particles was investigated by the principal component analysis (PCA). The results show that the mean PM10 concentration in classrooms is (176.56±57.63)
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| 3. |
- Wang, X. -C, et al.
(författare)
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Quantized H∞ control for uncertain networked system
- 2011
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Ingår i: Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology). - 1672-7207. ; 42:SUPPL. 1, s. 392-398
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Tidskriftsartikel (refereegranskat)abstract
- Network-induced delay, data packet drop-out and perturbation are common problems for networked system. The designing of quantized feedback H∞ controller, focusing on the above problem was studied. In this general model, two logarithms were quantized used for the quantizing of control signal and status signal, and the sufficient condition for the asymptotical stability of the network control systems and the design of quantized feedback controller was proposed according to the Lyapunov stability theory and linear matrix inequality. The quantized feedback controller can make the systems asymptotically stable and meet H∞ performance. The design is confirmed to be efficient by the simulation result.
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