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	Regularity of rural settlement changes driven by rapid urbanization in North China over the three decades 期刊论文 OAI收割 SCIENCE BULLETIN, 2023, 卷号: 68, 期号: 18, 页码: 2115-2124 作者: Liu, Yansui; Ou, Cong; Li, Yurui; Zhang, Liqiang; He, Jianhua \| 收藏 \| 浏览/下载：20/0 \| 提交时间：2023/11/06 Rural settlement changes Rapid urbanization Cost-effective approach Rural areal system Beijing-Tianjin-Hebei region
	impacts separation framework for performance prediction of middleware-based systems 学位论文 OAI收割 2009 Huang Xiang; Zhang Wenbo; Zhang Bo; Wei Jun \| 收藏 \| 浏览/下载：22/0 \| 提交时间：2011/03/20 aspect-oriented modeling cost effective approach middleware-based system model-based performance prediction software artifact software development middleware object-oriented programming software engineering
	Design of infrared afocal zoom system (EI CONFERENCE) 会议论文 OAI收割 ICO20: Optical Design and Fabrication, August 21, 2005 - August 26, 2005, Changchun, China 作者: Wang Y.; Jiang H.; Wang Y.; Wang Y.; Wang Y. 收藏 \| 浏览/下载：96/0 \| 提交时间：2013/03/25 The design method and result are described for an infrared afocal zoom system. Its zoom ratio is 4 (2) Functions such as changing the field-of-view and the corresponding field of view is 3-12. The working waveband is from 7.5m to 10.5m focusing for objects at finite distances and athermalizing the system can be achieved by axially moving a single element in the system. and its total length is required to be no more than 350mm. The final optical system consists of 7 elements with aspheric surfaces and a diffractive optical element. It achieves diffraction-limited imaging at the far infrared waveband. Two conclusions can be drawn from the design. (1) Using diffractive optical elements in the design of an infrared optical system is an effective approach to control color aberrations which eliminates the need to use exotic and expensive materials and helps to reduce the cost of the system