中国科学院机构知识库网格系统: 检索

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	Variations in Global Soil Moisture During the Past Decades: Climate or Human Causes? 期刊论文 OAI收割 WATER RESOURCES RESEARCH, 2023, 卷号: 59, 期号: 7, 页码: e2023WR034915 作者: Liu, Yangxiaoyue; Yang, Yaping; Song, Jia \| 收藏 \| 浏览/下载：23/0 \| 提交时间：2023/09/07 soil moisture spatial-temporal variation attribution analysis climatic causes human causes
	Characterization and causes analysis for algae blooms in large river system 期刊论文 OAI收割 SUSTAINABLE CITIES AND SOCIETY, 2019, 卷号: 51, 页码: 11 作者: Cheng, Bingfen; Xia, Rui; Zhang, Yuan; Yang, Zhongwen; Hu, Sheng \| 收藏 \| 浏览/下载：62/0 \| 提交时间：2020/05/19 Eutrophication Algal blooms River ecosystem Causes analysis
	Land use dynamics and landscape change pattern in Hetao irrigation district, Inner Mongolia, China 会议论文 OAI收割 6th International Symposium on Digital Earth: Data Processing and Applications, Beijing, China, September 9, 2009 - September 12,2009 Zhang, Yinhui; Luo, Yi; Zhao, Wenwu 收藏 \| 浏览/下载：27/0 \| 提交时间：2014/12/07 This study analyzed spatial and temporal changes in land use in an irrigation district covering an area of 1.7 million ha in Northern China by GIS analyses and also investigated changes in landscape pattern using the landscape structure analysis program FRAGSTATS over the study period from 1986 to 2000. The decreases in farmland and the increases in grassland area mainly resulted from the policy of grain for green and converting slope farmland into pasture from China government. In spite of the efforts to conserve the fragile ecosystem the land degradation including soil salinization and grassland degradation was spreading rapidly. The area of alkali-saline land increased by 22493 ha and about 50555 ha of dense grassland degraded into mid-density grassland. In terms of landscape fragmentation both farmland and dense grassland showed the tendency of increased fragmentation. Both adverse natural conditions and human activities are responsible for the land degradation expansion in Hetao irrigation district but the root causes are increasing population pressure and irrational human activities such as flooding irrigation method and over-grazing. To prevent land degradation from spreading population control and improvement of the management are prerequisite approaches. 2010 SPIE.
	Equivalent lenses of supersonic seeker's outflow refractive index field obtained by simulation and experiment (EI CONFERENCE) 会议论文 OAI收割 2008 International Conference on Optical Instruments and Technology: Optical Systems and Optoelectronic Instruments, November 16, 2008 - November 19, 2008, Beijing, China Qun W.; Hongguang J.; Ming X. 收藏 \| 浏览/下载：24/0 \| 提交时间：2013/03/25 In order to decrease the aerodynamic drag of supersonic image guide missile and design a non-spherical dome the outflow field of the missile's dome is simulated using FLUENT. Based on the simulated results the accurate density field of the outflow field at all kinds of flight conditions is obtained and then the refractive index field of the outflow field is gotten according to the Gladstone-Dale law. The results show that the shock wave induces the heterogeneity of the refractive index field and the turbulent causes distortion. The outflow field is divided into several zones which are taken as equivalent lenses for aberration analysis. 2009 SPIE.
	Chip design of linear CCD drive pulse generator and control interface (EI CONFERENCE) 会议论文 OAI收割 2nd International Symposium on Advanced Optical Manufacturing and Testing Technologies - Advanced Optical Manufacturing and Testing Technologies, November 2, 2005 - November 5, 2005, Xian, China 作者: Sun H.; Wang Y.; Wang Y.; Wang Y.; Wang Y. 收藏 \| 浏览/下载：30/0 \| 提交时间：2013/03/25 CCD noises and their causes are analyzed. Methods to control these noises such as Correlated Double Sampling (CDS) filtering cooling clamping and calibration are proposed. To improve CCD sensor's performances the IC called Analog Front End (AFE) integration of CDS clamping Programmable Gain Amplifier (PGA) offset and ADC which can fulfill the CDS and analog-to-digital conversion is employed to process the output signal of CCD. Based on the noise control approaches the idea of chip design of linear CCD drive pulse generator and control interface is introduced. The chip designed is playing the role of (1) drive pulse generator for both CCD and AFE and (2) interface helping to analysis and transfer control command and status information between MCU controller and drive pulse generator or between global control unit in the chip and CCD/AFE. There are 6 function blocks in the chip designed such as clock generator for CCD and AFE MCU interface AFE serial interface output interface CCD antiblooming parameter register and global control logic unit. These functions are implemented in a CPLD chip Xilinx XC2C256-6-VQ100 with 20MHz pixel frequency and 16-bit high resolution. This chip with the AFE can eliminate CCD noise largely and improve the SNR of CCD camera. At last the design result is presented.
	El Nino phenomenon in simple ocean data assimilation data 期刊论文 OAI收割 ACTA OCEANOLOGICA SINICA, 2005, 卷号: 24, 期号: 4, 页码: 43-53 作者: Cui, MC; Wu, LJ \| 收藏 \| 浏览/下载：15/0 \| 提交时间：2010/12/22 El Nino/la Nina Phenomenon Causes Extended Associate Pattern Analysis Soda Data