http://www.sciencedirect.com/science/article/pii/S1674987113000832     

J ianping C hen  Yanbo X u  X iang W ang  S hujun H e  D anping Y an  S haofeng L iu  Y ongliao Z ou  Y ongchun Zheng 《地学前缘(英文版)》2014,5(2):227-235

The Sinus Iridum region, the first choice for China＇s＂Lunar Exploration Project＂is located at the center of the lunar LQ-4 area and is the site of Chang＇e-3 （CE-3）＇s soft landing. To make the scientific exploration of Chang＇e-3 more targeted and scientific, and to obtain a better macro-level understanding of the geotectonic environment of the Sinus Iridum region, the tectonic elements in LQ-4 region have been studied and the typical structures were analyzed statistically using data from CE-1, Clementine, LRO and Lunar Prospector missions. Also, the mineral components and periods of mare basalt activities in the study area have been ascertained. The present study divides the tectonic units and establishes the major tectonic events and sequence of evolution in the study area based on morphology, mineral constituents, and tectonic element distribution.  相似文献   

Applying the Hidden Markov Model to Analyze Urban Mobility Patterns: An Interdisciplinary Approach     

LOO Becky P Y  ZHANG Feiyang  HSIAO Janet H  CHAN Antoni B  LAN Hui 《中国地理科学(英文版)》2021,(1):1-13

With the emergence of the Internet of Things(IoT), there has been a proliferation of urban studies using big data. Yet, another type of urban research innovations that involve interdisciplinary thinking and methods remains underdeveloped. This paper represents an attempt to adopt a Hidden Markov Model(HMM) toolbox developed in Computer Science for the analysis of eye movement patterns in Psychology to answer urban mobility questions in Geography. The main idea is that both people’s eye movements and travel behavior follow the stop-travel-stop pattern, which can be summarized using HMM. Methodological challenges were addressed by adjusting the HMM to analyze territory-wide travel survey data in Hong Kong, China. By using the adjusted toolbox to identify the activitytravel patterns of working adults in Hong Kong, two distinctive groups of balanced(38.4%) and work-oriented(61.6%) lifestyles were identified. With some notable exceptions, working adults living in the urban core were having a more work-oriented lifestyle. Those with a balanced lifestyle were having a relatively compact zone of non-work activities around their homes but a relatively long commuting distance. Furthermore, working females tend to spend more time at home than their counterparts, regardless of their marital status and lifestyle. Overall, this interdisciplinary research demonstrates an attempt to integrate spatial, temporal, and sequential information for understanding people’s behavior in urban mobility research.  相似文献   

Chemometrics data analysis of marine water quality and source identification in Southern Hong Kong   总被引：3，自引：0，他引：3  

Zhou F  Guo H  Liu Y  Jiang Y 《Marine pollution bulletin》2007,54(6):745-756

Various chemometric methods were used to analyze data sets of marine water quality for 19 parameters measured at 16 different sites of southern Hong Kong from 2000 to 2004 (18,240 observations), to determine temporal and spatial variations in marine water quality and identify pollution sources. Hierarchical cluster analysis (CA) grouped the 12 months into three periods (January-April, May-August and September-December) and the 16 sampling sites into two groups (A and B) based on similarities in marine water-quality characteristics. Discriminant analysis (DA) was important in data reduction because it used only eight parameters (TEMP, TURB, Si, NO(3)(-)-N, NH(4)(+)-N, NO(2)(-)-N, DO, and Chl-a) to correctly assign about 86% of the cases, and five parameters (SD, NH(4)(+)-N, TP, NO(2)(-)-N, and BOD(5)) to correctly assign >81.15% of the cases. In addition, principal component analysis (PCA) identified four latent pollution sources for groups A and B: organic/eutrophication pollution, natural pollution, mineral pollution, and nutrient/fecal pollution. Furthermore, during the second and third periods, all sites received more organic/eutrophication pollution and natural pollution than in the first period. SM5, SM6, SM17, SM10, SM11, SM12, and SM13 (second period) were affected by organic and eutrophication pollution, whereas SM3 (third period) and SM9 (second period) were influenced by natural pollution. However, differences between mineral pollution and nutrient/fecal pollution were not significant among the three periods. SM17 and SM10 were affected by mineral pollution, whereas SM4 and SM9 were highly polluted by nitrogenous nutrient/fecal pollution.  相似文献   

Predicting the tails of breakthrough curves in regional-scale alluvial systems   总被引：1，自引：0，他引：1  

Zhang Y  Benson DA  Baeumer B 《Ground water》2007,45(4):473-484

The late tail of the breakthrough curve (BTC) of a conservative tracer in a regional-scale alluvial system is explored using Monte Carlo simulations. The ensemble numerical BTC, for an instantaneous point source injected into the mobile domain, has a heavy late tail transforming from power law to exponential due to a maximum thickness of clayey material. Haggerty et al.'s (2000) multiple-rate mass transfer (MRMT) method is used to predict the numerical late-time BTCs for solutes in the mobile phase. We use a simple analysis of the thicknesses of fine-grained units noted in boring logs to construct the memory function that describes the slow decline of concentrations at very late time. The good fit between the predictions and the numerical results indicates that the late-time BTC can be approximated by a summation of a small number of exponential functions, and its shape depends primarily on the thicknesses and the associated volume fractions of immobile water in "blocks" of fine-grained material. The prediction of the late-time BTC using the MRMT method relies on an estimate of the average advective residence time, t(ad). The predictions are not sensitive to estimation errors in t(ad), which can be approximated by L/v , where v is the arithmetic mean ground water velocity and L is the transport distance. This is the first example of deriving an analytical MRMT model from measured hydrofacies properties to predict the late-time BTC. The parsimonious model directly and quantitatively relates the observable subsurface heterogeneity to nonlocal transport parameters.  相似文献   

On the relation between steep monoclinal flexure zones and steep hydraulic gradients   总被引：1，自引：0，他引：1  

Yechieli Y  Kafri U  Wollman S  Lyakhovsky V  Weinberger R 《Ground water》2007,45(5):616-626

Steep hydraulic gradients are found in association with steep monoclinal flexures. However, the physics of the reduction of the hydraulic conductivity, which is responsible for the steep gradients, has seldom been studied. We present results of hydrological and mechanical modeling aiming to study the effect of such steep hydraulic gradients demonstrated in the Judea Group Aquifer system, Israel. The hydrological configuration of steep dips and anisotropy between flows parallel and perpendicular to the bedding planes was simulated using the FEFLOW code. It exhibited a situation whereby part of the flow is oblique to the bedding planes and therefore some steepening of the hydraulic gradients occurred due to actual conductivity reduction. However, this reduction is not enough to account for the steeper gradients observed. The effect of a deep-seated reverse fault under the monocline on the permeability distribution within the structure was examined by numerical mechanical simulations. It exhibited a compressional stress distribution in the steep part of the monocline, which, due to shortening and closure of joints and voids, is presumably responsible for a significant pressure-induced permeability reduction. This process by itself in a layered structure, including interlayering of thin marl layers, could be responsible for the steep hydraulic gradients in the steep part of the monocline.  相似文献   

青藏高原那曲地区冰雹天气系统中的大气电场     

周筠珺  陈成品  刘黎平  楚荣忠  冯锦明  张彤  宋新民  M. Kajikawa  H. Fujii  Y. Aoi  T. Koike  S. Shimizu  K. Ueno 《高原气象》2000,19(3)

利用1998年4～9月间进行的GAME-TIBET青藏高原云和降水的多普勒雷达及大气平均电场加强期观测实验资料, 对青藏高原那曲地区的冰雹天气系统中的大气电场作了定量观测和研究.结果表明: 在降雹过程中大气电场强度基本上均为负值, 其峰值也均强于-22 kVm-1; 在降雹过程中随着降雹时间的临近, 大气电场强度不断增强, 但降雹开始时大气电场强度并未达到其峰值, 峰值出现的时刻比开始降雹的时刻略有滞后; 在各降雹日中, 较强的大气电场强度基本上对应着各冰雹谱分布段较多的冰雹数目, 而这种较好的相关在各谱分布段上都表现出来; 随着降雹时间的临近, 每5 min闪电频数不断增强.在开始降雹时每5 min闪电频数平均达到43, 峰值的出现时刻略滞后于开始降雹的时刻, 这一滞后时间一般平均在3 min左右; 在降雹过程中, 单位面积中的冰雹数目与对应时段内总闪电数有着较好的对数关系, 相关系数R为0.954 0.在降雹过程的时间序列上, 冰雹云成熟期过后, 总闪电次数与冰雹降雹率成反相关.  相似文献   

Smart Sediment Particle: A novel approach to investigating fluvial bed entrainment using instrumented sensors     

Yushu Xie  Bruce W.Melville  Asaad Y.Shamseldin  Colin N.Whittaker  Yifan Yang 《国际泥沙研究》2023,38(1):66-82

The Smart Sediment Particle(SSP) instrumented with multiple sensors to obtain tri-axial linear accelerations is used for studying the mechanism of coarse grain entrainment. Three bed arrangements are tested to examine their influences on entrainment processes and the threshold force and impulse conditions. The SSP shows satisfactory precision to capture the imperceptible movement tendencies immediately(e.g., 0.15 s) after the dislodgement. The experimental results show that bed packing can signi...  相似文献   

编码激励信号在岩石超声波速度检测中的应用     

H.Z.Wu  W.Zhu  T.M.He  Z.Y.Liu  X.W.Lan  兰晓雯  朱维 《地球与行星物理论评》2020,51(5)

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20世纪早期北极的地震活动:1904～1920年地震的重定位     

A.N.Morozov  N.V.Vaganova  E.V.Shakhova  Y.V.Konechnaya  V.E.Asming  G.N.Antonovskaya  Z.A.Evtyugina  辛雪侠  高翔 《地球与行星物理论评》2020,51(4)

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Photometric Survey of Galactic Open Clusters     

M.G. Lee  H.B. Ann  M.Y. Chun  S. L. Kim  Y. B. Jeon  B. G. Park  I. S. Yuk  H.Sung 《天文研究与技术》1999,(Z1)

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