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陈传康的学术生命路径和学术树 总被引:2,自引:0,他引:2
通过扩展传统的生命路径 ( life path)概念、并建立学术树 ( discipline tree)概念 ,研究已故当代中国著名地理学家、旅游学家陈传康教授的学术史。在统计了陈传康教授全部 1 2 1 2种次的学术著述的基础上 ,首先在时间纬度上建立了学术生命路径曲线、系统式和时序式生命路径表 ,用以统计分析陈传康教授的学术论著种次的分布情况和变迁过程 ,一方面反映出著作量随中国当代历史的脉动而出现的起伏变化 ,另一方面通过观察时间轴上这些著述的学科点的分布变化 ,不仅体现 2 0世纪 5 0年代~ 90年代陈传康学术偏好的转徙 ,也反映出 5 0年间中国地理学整体的变化轨迹。利用学术树的概念 ,统计分析陈传康一生构筑的个人学术体系 ,最终勾勒出其一生经营的学术群落的整体景观。 相似文献
94.
An important problem in hydrologic science is understanding how river flow is influenced by rainfall properties and drainage basin characteristics. In this paper we consider one approach, the use of mass exponents, in examining the relation of river flow to rainfall and the channel network, which provides the primary conduit for transport of water to the outlet in a large basin. Mass exponents, which characterize the power-law behavior of moments as a function of scale, are ideally suited for defining scaling behavior of processes that exhibit a high degree of variability or intermittency. The main result in this paper is an expression relating the mass exponent of flow resulting from an instantaneous burst of rainfall to the mass exponents of spatial rainfall and that of the network width function. Spatial rainfall is modeled as a random multiplicative cascade and the channel network as a recursive replacement tree; these fractal models reproduce certain types of self-similar behavior seen in actual rainfall and networks. It is shown that under these modeling assumptions the scaling behavior of flow mirrors that of rainfall if rainfall is highly variable in space, and on the other hand flow mirrors the structure of the network if rainfall is not so highly variable. 相似文献
95.
用地层倾角测井资料解释复杂构造的方法 总被引:1,自引:0,他引:1
倾角测井矢量图可以标示出井眼范围内各深度点的地层产状,一定的地层构造形态在矢量图上有一定的倾角矢量组合模式。通过正演计算,总结出了19种褶曲和断层等构造组合模式的样板及在一口井内各构造模式间的“串”、“缺”、“嵌”连接规律。对照组合模式样板进行矢量组合模式识别,采用“倾角矢量逐点叠加法”,可把井眼范围纵向排列的倾角矢量转换成任意方位的地层视产状,绘制构造剖面图。用多个剖面的地层空间坐标数据可绘制倾角构造平面图,确定钻遇构造的形态。据此原理,编制了一套倾角测井构造解释软件系统。 相似文献
96.
本文在综述了目前稳定流涌水量经验方程建立方法的基础上,根据最小二乘法原理,提出了一种新的方法—最小残差法,并给出了计算实例。计算表明,最小残差法是建立稳定法涌水量经验方程的一种较好方法,计算过程在微机上易于实现。 相似文献
97.
尝试建立变截面桩的挠曲线微分方程,继而提出了变截面优化桩的概念,并给出了端承桩的一种优化算法。还以圆截面大孔径挖孔灌注桩为例,在桩顶受竖向荷载、水平横向力及弯矩作用时,进行了最轻重量设计。通过计算表明,使用变截面优化桩可使桩的体积减少30%以上。 相似文献
98.
ABSTRACT In many places, magnitudes and frequencies of floods are expected to increase due to climate change. To understand these changes better, trend analyses of historical data are helpful. However, traditional trend analyses do not address issues related to shifts in the relative contributions of rainfall versus snowmelt floods, or in the frequency of a particular flood type. We present a novel approach for quantifying such trends in time series of floods using a fuzzy decision tree for event classification and applied it to maximal annual and seasonal floods in 27 alpine catchments for the period 1980–2014. Trends in flood types were studied with Sen’s slope and double mass curves. Our results reveal a decreasing number of rain-on-snow and an increasing number of short rainfall events in all catchments, with flash floods increasing in smaller catchments. Overall, the results demonstrate the value of incorporating a fuzzy flood-type classification into flood trend analyses. 相似文献
99.
ABSTRACTSustainable intensification of existing cropland is one of the most viable options for meeting the escalating food demands of the ever-increasing population in the world. Accurate geospatial data about the potential single-crop (rice-fallows) areas is vital for policymakers to target the agro-technologies for enhancing crop productivity and intensification. Therefore, the study aimed to evaluate and understand the dynamics of rice-fallows in the Odisha state of India, using SAR (Sentinel-1) and Optical (Landsat OLI) datasets. This study utilized a decision-tree approach and Principal component analysis (PCA) for the segmentation and separation of different vegetation classes. The estimated overall accuracy of extracted rice-fallow maps was in the range of 84 to 85 percent. The study identified about 2.2, 2.0 and 2.1mha of Rice-Fallows in the years 2015–16, 2016–17, and 2017–18, respectively. The combined analysis (all three years) of rice-fallow maps identified about 1.34mha of permanent rice-fallows, whereas the remaining 0.6–0.8mha area was under the current-fallow category. About 50% of the total permanent rice-fallows were detected in the rainfed areas of Mayurbhanj, Bhadrak, Bolangir, Sundargarh, Keonjhar, Baleswar, Nawarangpur and Bargarh districts. The study also illustrated the time-series profiles of SMAP (soil moisture) datasets for the ten agroclimatic zones of the Odisha, which can be utilized (along with rice-fallow maps) for the selection of crop and cultivars (e.g. short or medium duration pulses or oilseeds) to target the rice fallows. The approach utilized in the current study can be scaled up in similar areas of South and South-east Asia and Africa to identify single-crop areas for targeting improved technologies for enhanced crop productivity and intensification. 相似文献
100.
工业指标的"多年一贯制"不利于合理充分地利用矿产资源,文章提出适合经济规律的工业指标制定办法,建议地质技术人员按照矿山年总成本和矿产品市场价格及时修正工业指标,以便使项目上马决策趋于正确. 相似文献