问题
单项选择题
一阶系统的单位阶跃响应的动态过程为( )。
A．振荡发散过程
B．等幅振荡过程
C．正弦衰减振荡过程
D．单调指数上升，最终趋于固定值
答案
参考答案：D
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一阶系统的单位阶跃响应的动态过程为( )。
A．振荡发散过程
B．等幅振荡过程
C．正弦衰减振荡过程
D．单调指数上升，最终趋于固定值
参考答案：D
| 任务型阅读。 BEIJING, March 9-The central government will require an additional three years of use for official vehicles for ministers (部长) and governors (政府官员) to reduce the costs of purchasing new cars, media have reported. The new rule has been applied among all Party and government departments nationwide, the Beijing News reported on Tuesday. The new rule has not yet been made public, said Li, a member of the Chinese People's Political Consultative Conference National Committee. Under the old rules, the cars used by ministerlevel officials could be replaced as often as every five years, Li said. These officials will also continue to use the same cars when they take new posts, he added. The new rule also reiterated (重申) that officials ranking below ministeror governorlevels should not be allocated cars. The cars possessed by their departments should be used on demand. "It violates the rules for lowerranking-even countylevelofficials to be allocated cars," Li said. Purchases of vehicles for official use have been heavily investigated, as they account for a large expenditure of public funds every year. A survey on the Web news www.ifeng.com found 59 percent of respondents believed the new rule will be difficult to obey because it is related to officials' interests. Local government departments had stopped approvals for requests for such vehicles and had started to limit the number of such cars under the new rules, Li said. "The future reform of official vehicle use will introduce market systems", Li said. Premier Wen Jiabao said in the annual government work report on Saturday that expenditures on such vehicles will not increase in 2011 compared with a year ago. Beijing's standing deputy mayor Ji Lin last week said the municipal government will release the number of vehicles for official use in the capital as early as at the end of this month. Earlier this month, the Ministry of Finance had published a rule regulating the budgets for such vehicles.
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