Browsing by Author "Li, SL"

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An optimization model for assessing flight technical delay
(2002-06-01)
Wong, JT
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Li, SL
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Gillingwater, D
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
This paper identifies the causes as well as the practical measurement of aircraft flight delays. The performance of air traffic management is measured by examining technical delays and scheduled timetable delays, which are derived from a mathematical programming model. To validate the optimization model, flight delays are simulated under various service rules. The outcome of the simulation runs shows that the average delay for each aircraft estimated from the optimization model is marginally higher than that from the simulation run under the "first come first serve" rule. However, under the "arrival flight first" rule, the optimization model's results are either higher or lower than those of the simulation model. Nonetheless, both sets of simulated delays are strongly correlated with those of the optimization model. Results from regression analyses show that the optimization model has the capacity to predict flight technical delays.
Superconductivity of alpha-TiAl alloys
(2000-11-01)
Liu, SM
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Jing, XN
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Lu, L
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Li, SL
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Lin, JJ
The superconducting transition temperature Tc of alpha TiAl alloys has been measured up to 10 atomic percentage of Al. T-c monotonously increases with a tendency to saturation for high Al content.
Upper critical field of Ti and alpha-TiAl alloys: Evidence of an intrinsic type-II superconductivity in pure Ti
(2000-10-01)
Liu, SM
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Zhang, DL
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Jing, XN
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Lu, L
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Li, SL
The upper critical field H-c2 of alpha-Ti1-xAlx(0 less than or equal to x less than or equal to 0.1) alloys has been investigated in detail. The behaviors can well be described by the theory of type-II superconductors. The electronic specific heat deduced from the superconducting properties is in excellent agreement with previous calorimetric measurements. However, the Fermi velocity obtained here is substantially lower than predicted by band calculation. The present work gives clear evidence that pure Ti is an intrinsic type-II superconducting element due to its very low renormalized Fermi velocity.