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1.
Materials (Basel) ; 17(17)2024 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-39274777

RESUMEN

Elevated stations are integral components of urban rail transit systems, significantly impacting passengers' travel experience and the operational efficiency of the transportation system. However, current elevated station designs often do not sufficiently consider the structural dynamic response under various operating conditions. This oversight can limit the operational efficiency of the stations and pose potential safety hazards. Addressing this issue, this study establishes a vehicle-bridge-station spatial coupling vibration simulation model utilizing the self-developed software GSAP V1.0, focusing on integrated station-bridge and combined station-bridge elevated station designs. The simulation results are meticulously compared with field data to ensure the fidelity of the model. Analyzing the dynamic response of the station in relation to train parameters reveals significant insights. Notably, under similar travel conditions, integrated stations exhibit lower vertical acceleration in the rail-bearing layer compared to combined stations, while the vertical acceleration patterns at the platform and hall layers demonstrate contrasting behaviors. At lower speeds, the vertical acceleration at the station concourse level is comparable for both station types, yet integrated stations exhibit notably higher platform-level acceleration. Conversely, under high-speed conditions, integrated stations show increased vertical acceleration at the platform and hall levels compared to combined stations, particularly under unloaded double-line working conditions, indicating a superior dynamic performance of combined stations in complex operational scenarios. However, challenges such as increased station height due to bridge box girder maintenance, track layer waterproofing, and track girder support maintenance exist for combined stations, warranting comprehensive evaluation for station selection. Further analysis of integrated station-bridge structures reveals that adjustments in the floor slab thickness at the rail-bearing and platform levels significantly reduce dynamic responses, whereas increasing the rail beam height notably diminishes displacement responses. Conversely, alterations in the waiting hall floor slab thickness and frame column cross-sections exhibit a minimal impact on the station dynamics. Overall, optimizing structural dimensions can effectively mitigate dynamic responses, offering valuable insights for station design and operation.

2.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 10): o2454, 2009 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-21577909

RESUMEN

The title compound, C(10)H(16)Br(2)N(4), was synthesized by the reaction of 1-methyl-imidazole and 1,2-dibromo-ethane in toluene. The complete dication is generated by a crystallographic inversion centre situated at the mid-point of the ethane C-C bond. In the crystal structure, weak inter-molecular C-H⋯Br inter-actions link the mol-ecules into chains along the b axis and an intramolecular C-H⋯Br close contact is also present.

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