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871.
通过降水,土壤水分,天然草场产草量之间建立的统计关系,来说明水分供应是影响牧草产量的重要因素,并依据降水和土壤水分与牧草产草量的关系划分出牧草生长中水分供给的正常,干旱等指标。 相似文献
872.
立体视觉的摄影测量理论 总被引:1,自引:0,他引:1
单杰 《武汉大学学报(信息科学版)》1998,(4)
从引入空间投影变换的概念入手,证明了体积之交比为一般的投影不变量,从而将其作为描述物体的度量。通过对基础矩阵进行合适的分解,导出了确定投影变换模型之齐次坐标和投影坐标的方法。提出了三维直接线性变换用于由物体的投影变换模型进行物体重建。实验分析证实了所述理论和方法的正确性。 相似文献
873.
淮河流域洪涝变化吸引子维数研究 总被引:15,自引:1,他引:14
淮河流域洪涝序列的功率谱表现出了较好的混沌谱特征,这是序列呈分形结构的内在原因。洪涝序列及其不同平滑序列的关联维数表明,序列平滑程度越大,关联维数越小,关联维数反映了序列所在系统的层次,是系统结构复杂性的重要量度,是 系统建模所需独立变量的控制参数。要恰当地描述淮河流域洪涝发生系数,需构造至少5个状态变量的动力学系统。 相似文献
874.
苍山5.2级地震前十里泉电厂井地下水离子多组分的变化特征及机制讨论 总被引:3,自引:0,他引:3
1995年9月20日山东苍山5.2级地震前,山东枣庄十里电厂水化学现观测井(Δ=km)水离子多组分出现了较为同步的异常变化。本文以此为基础,分析研究了这些异常的变化特征,讨论了异常出现的机制,研究认为,枣庄十里泉电厂水化学观测井水离子多组分的异常同步变化及相互印证,提高了异常的可信度;与水中常见离子组分相比,其中水汞的震前异常变化幅度最大,异常特征明显;十里泉电厂水化学观测井水离子多组分的同步异常 相似文献
875.
You-Kuan Zhang Jie Lin 《Stochastic Environmental Research and Risk Assessment (SERRA)》1998,12(2):117-140
Transport of non-ergodic solute plumes by steady-state groundwater flow with a uniform mean velocity, μ, were simulated with Monte Carlo approach in a two-dimensional heterogeneous and statistically isotropic aquifer whose transmissivity,
T, is log-normally distributed with an exponential covariance. The ensemble averages of the second spatial moments of the plume
about its center of mass, <S
i
i
(t)>, and the plume centroid covariance, R
i
i
(t) (i=1,2), were simulated for the variance of Y=log T, σ
Y
2=0.1, 0.5 and 1.0 and line sources normal or parallel to μ of three dimensionless lengths, 1, 5, and 10. For σ
Y
2=0.1, all simulated <S
i
i
(t)>−S
i
i
(0) and R
i
i
(t) agree well with the first-order theoretical values, where S
i
i
(0) are the initial values of S
i
i
(t). For σ
Y
2=0.5 and 1.0 and the line sources normal to μ, the simulated longitudinal moments, <S
11(t)>−S
11(0) and R
11(t), agree well with the first-order theoretical results but the simulated transverse moments <S
22(t)>−S
22(0) and R
22(t) are significantly larger than the first-order values. For the same two larger values of σ
Y
2 but the line sources parallel to μ, the simulated <S
11(t)>−S
11(0) are larger than but the simulated R
11 are smaller than the first-order values, and both simulated <S
22(t)>−S
22(0) and R
22(t) stay larger than the first-order values. For a fixed value of σ
Y
2, the summations of <S
i
i
(t)>−S
i
i
(0) and R
i
i
, i.e., X
i
i
(i=1,2), remain almost the same no matter what kind of source simulated. The simulated X
11 are in good agreement with the first-order theory but the simulated X
22 are significantly larger than the first-order values. The simulated X
22, however, are in excellent agreement with a previous modeling result and both of them are very close to the values derived
using Corrsin's conjecture. It is found that the transverse moments may be significantly underestimated if less accurate hydraulic
head solutions are used and that the decreasing of <S
22(t)>−S
22(0) with time or a negative effective dispersivity, defined as , may happen in the case of a line source parallel to μ where σ
Y
2 is small. 相似文献
876.
1983年菏泽5.9级地震前地下流体异常分布特征及其有关问题讨论 总被引:1,自引:0,他引:1
全面、系统地分析研究了菏泽5.9级地夺前地下流体异常时空分布及其场兆、源兆特征。结果表明,异常空间分布与活动构造密切相关,断裂端部和交汇处是异常响应的第三地区。单位面积异常台项数,震中及附近地区远高于外围地区。震前1个月左右,异常台项月频次大幅度增高,单项异常的时间演化有持续型、完整型和突跳型三种类型。源兆异常具有中期、短期、临震异常配套、水化我组分同步异常变化、宏观异常多点成片、持续时间长、幅度 相似文献
877.
贵金属资源的应用及开发 总被引:1,自引:1,他引:0
将贵金属的应用,资源分布,生产和贵金属的分析化学结合在一起进行了综述,由于贵金属资源的短缺性及考虑可持续发展战略,特别介绍了贵金属资源的二次回收问题,并对其将来的发展作了一定的评价和展望。 相似文献
878.
本文利用近三十年来的地面测量资料和东亚地区11个地磁台的资料,以及1965.0、1975.0国际地磁参考场等资料,对东亚大陆磁场的时、空变化特征进行了研究。内容包括:东亚大陆磁场的空间分布特征及场源深度的估算,东亚大陆磁场的中心位置及其磁场强度、磁场方向,近三十年来东亚大陆磁场的长期变化特征等。得到的主要结果是:1.东亚大陆磁场的中心位置近三十年来没有西向漂移的迹象,从而推断它的长期变化主要由场源强度的变化所引起,而不是主要由非偶场的西向漂移所引起;2.东亚大陆磁场的中心与它的长期变化的中心不相一致,同时,在青藏高原的东部还可能存在一弱中心。 相似文献
879.
Tianshan is one of the longest and most active intracontinental orogenic belts in the world. Due to the collision between Indian and Eurasian plates since Cenozoic, the Tianshan has been suffering from intense compression, shortening and uplifting. With the continuous extension of deformation to the foreland direction, a series of active reverse fault fold belts have been formed. The Xihu anticline is the fourth row of active fold reverse fault zone on the leading edge of the north Tianshan foreland basin. For the north Tianshan Mountains, predecessors have carried out a lot of research on the activity of the second and third rows of the active fold-reverse faults, and achieved fruitful results. But there is no systematic study on the Quaternary activities of the Xihu anticline zone. How is the structural belt distributed in space?What are the geometric and kinematic characteristics?What are the fold types and growth mechanism?How does the deformation amount and characteristics of anticline change?In view of these problems, we chose Xihu anticline as the research object. Through the analysis of surface geology, topography and geomorphology and the interpretation of seismic reflection profile across the anticline, we studied the geometry, kinematic characteristics, fold type and growth mechanism of the structural belt, and calculated the shortening, uplift and interlayer strain of the anticline by area depth strain analysis.
In this paper, by interpreting the five seismic reflection profiles across the anticline belt, and combining the characteristics of surface geology and geomorphology, we studied the types, growth mechanism, geometry and kinematics characteristics, and deformation amount of the fold. The deformation length of Xihu anticline is more than 47km from west to east, in which the hidden length is more than 14km. The maximum deformation width of the exposed area is 8.5km. The Xihu anticline is characterized by small surface deformation, simple structural style and symmetrical occurrence. The interpretation of seismic reflection profile shows that the deep structural style of the anticline is relatively complex. In addition to the continuous development of a series of secondary faults in the interior of Xihu anticline, an anticline with small deformation amplitude(Xihubei anticline)is continuously developed in the north of Xihu anticline. The terrain high point of Xihu anticline is located about 12km west of Kuitun River. The deformation amplitude decreases rapidly to the east and decreases slowly to the west, which is consistent with the interpretation results of seismic reflection profile and the calculation results of shortening. The Xihu anticline is a detachment fold with the growth type of limb rotation. The deformation of Xihu anticline is calculated by area depth strain analysis method. The shortening of five seismic reflection sections A, B, C, D and E is(650±70) m, (1 070±70) m, (780±50) m, (200±40) m and(130±30) m, respectively. The shortening amount is the largest near the seismic reflection profile B of the anticline, and decreases gradually along the strike to the east and west ends of the anticline, with a more rapidly decrease to the east, which indicates that the topographic high point is also a structural high point. The excess area caused by the inflow of external material or outflow of internal matter is between -0.34km2 to 0.56km2. The average shortening of the Xihubei anticline is between(60±10) m and(130±40) m, and the excess area caused by the inflow of external material is between 0.50km2 and 0.74km2. The initial locations of the growth strata at the east part is about 1.9~2.0km underground, and the initial location of the growth strata at the west part is about 3.7km underground. We can see the strata overlying the Xihu anticline at 3.3km under ground, the strata above are basically not deformed, indicating that this section of the anticline is no longer active. 相似文献
In this paper, by interpreting the five seismic reflection profiles across the anticline belt, and combining the characteristics of surface geology and geomorphology, we studied the types, growth mechanism, geometry and kinematics characteristics, and deformation amount of the fold. The deformation length of Xihu anticline is more than 47km from west to east, in which the hidden length is more than 14km. The maximum deformation width of the exposed area is 8.5km. The Xihu anticline is characterized by small surface deformation, simple structural style and symmetrical occurrence. The interpretation of seismic reflection profile shows that the deep structural style of the anticline is relatively complex. In addition to the continuous development of a series of secondary faults in the interior of Xihu anticline, an anticline with small deformation amplitude(Xihubei anticline)is continuously developed in the north of Xihu anticline. The terrain high point of Xihu anticline is located about 12km west of Kuitun River. The deformation amplitude decreases rapidly to the east and decreases slowly to the west, which is consistent with the interpretation results of seismic reflection profile and the calculation results of shortening. The Xihu anticline is a detachment fold with the growth type of limb rotation. The deformation of Xihu anticline is calculated by area depth strain analysis method. The shortening of five seismic reflection sections A, B, C, D and E is(650±70) m, (1 070±70) m, (780±50) m, (200±40) m and(130±30) m, respectively. The shortening amount is the largest near the seismic reflection profile B of the anticline, and decreases gradually along the strike to the east and west ends of the anticline, with a more rapidly decrease to the east, which indicates that the topographic high point is also a structural high point. The excess area caused by the inflow of external material or outflow of internal matter is between -0.34km2 to 0.56km2. The average shortening of the Xihubei anticline is between(60±10) m and(130±40) m, and the excess area caused by the inflow of external material is between 0.50km2 and 0.74km2. The initial locations of the growth strata at the east part is about 1.9~2.0km underground, and the initial location of the growth strata at the west part is about 3.7km underground. We can see the strata overlying the Xihu anticline at 3.3km under ground, the strata above are basically not deformed, indicating that this section of the anticline is no longer active. 相似文献
880.