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971.
河西地区重力动态变化的二维离散小波多尺度分解 总被引:7,自引:5,他引:2
采用二维离散小波的多尺度分解技术,对1994~1995年和2002~2003年的河西地区重力动态变化进行分解,提取该地区不同层次的重力动态变化异常,结果反映了不同深度在一定尺度意义上的介质密度的动态变化分布。 相似文献
972.
依据随州三里岗ML4.7地震序列的地震监测和宏观调查所获得的基础资料,对此次地震序列的时空强特征及地震成因机理进行了分析。为使地震资料准确可靠,对混淆在序列中的爆破波形与地震波形进行了鉴别和剔除。结合这些基础资料和震源机制解结果。分析认为随州地震序列在成因上与该地区存在的北东和北西向两组断裂构造有关,但主发震构造是北西向断裂。 相似文献
973.
身份认证对于保证信息只被合法授权用户获取和访问起着重要作用,因而建立强有力的身份认证机制成为信息安全的关键之一。以现有动态口令身份认证主流技术为参照,提出了一种动态口令同步认证方法,以实现动态口令安全性、有效性与同步程度、验证效率之间的最优化配置。 相似文献
974.
张秋文 《大地测量与地球动力学》1994,(4)
本文在研究长江三峡及邻区地壳─上地幔结构和现今地壳重力场基础上,分析了该区板内中强地震的孕震动力学过程,探讨了整体上相对稳定的长江三峡及邻区孕育和发生中强地震的动力学机制,并提出了该区板内中强地震预测的动力学标志。 相似文献
975.
Remote sensing technique has played an important role in land use dynamic monitoring, but as for the land use dynamic monitoring
at county level, traditional remote sensing methods such as satellite imagery visual interpretation and computer classification
can not meet its demand for accuracy. The result of 1: 10 000 land use investigation map has high accuracy, but this method
can not be used to dynamically monitor the land use because of its big expenses, long period and difficulty in updating data.
In this paper, the characteristics of physiognomy, climate and the status of land use in Dehui County are taken into consideration
and a set of method, which takes use of 3S techniques and applies to Northeast China Plain, is come up with. When the land
use type of a land parcel changed as a whole, the date updating can be make by changing its land type ID in the attribute
table in a GIS. When the land use type of an irregular area changed, GPS receivers are used to position its border. This set
of method is characteristic of high accuracy and low expenses. It gets the information of land use change timely and can be
used to dynamically monitor the land use.
Foundation item: Under the auspices of the key project of the National Ninth Five-year Plan (96-B02-01-07).
Biography: LI Lin-yi (1968 —), female, a native of Jilin, Ph. D. candidate of Changchun Institute of Geography, the Chinese
Academy of Sciences. Her research interest includes land use change monitoring and crop yield estimation using “3S” techniques. 相似文献
976.
The Doppler Effect and Spectral Energy Distribution of Blazars 总被引:2,自引:0,他引:2
The relativistic beaming model is adopted to discuss quantitatively the observational differences between radio-selected BL Lac objects (RBLs) and X-ray-selected BL Lac objects (XBLs), and between BL Lac objects and flat spectrum radio quasars (FSRQs). The main results are the following:(1) In the Doppler corrected color-color(αro^in-αox^in) diagram,XBLs and FSRQs occupy separated regions, while RBLs bridge the gap between them. These properties suggest that similar intrinsic physical processes operate in all the objects under a range of intrinsic physical conditions. (2) Our results are consistent with the results of Sambruna, Maraschi and Urry (1996) from other methods. We show the αxox introduced by Sambruna to be a good index for describing the energy distribution because it represents the intrinsic energy distribution and includes the Doppler correction. (3)The Doppler effect of relativistic beaming is the main mechanism, and the physical differences(such as magnetic fields, electron energies) are also important complementary factors for understanding the relation between XBLs and RBLS. 相似文献
977.
Soil water repellency may be characterized in terms of the delayed infiltration time of a water droplet resting on the soil surface, which is, water drop penetration time (WDPT), or repellency persistence. Such repellency persistence varies nonlinearly with soil water content (θg), although no models have been proposed to reproduce the variation of WDPT with θg in soils. Dynamic factor analysis (DFA) is used to identify two common patterns of unexplained variability in a scattered dataset of WDPT versus θg measurements. A four‐parameter lognormal distribution was fitted to both common patterns obtained by DFA, and these were combined additively in a weighted multiple linear bimodal model. We show how such an empirical model is capable of reproducing a large variety of WDPT versus θg curve shapes (N = 80) both within a wide range of measured WDPTs (0–17 000 s) and for samples with organic matter content ranging from 21·7 to 80·6 g (100 g)?1. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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