Simplified lateral free field boundary based on a lumped mass system     

Dong  Zhengfang  Kuo  Chenyang  Shi  Chengli  Wang  Junjie 《地震工程与工程振动(英文版)》2022,21(4):913-928

After reviewing the studies on the lateral artificial boundaries in dynamic soil-structure interactions, the free field boundary was theoretically analyzed in asymmetric- and symmetric-matrix forms. First, the lumped mass system was combined with viscous or viscoelastic elements to obtain a lumped mass-free field boundary. Second, typical examples were implemented using the finite element software ABAQUS. The incident shear wave was taken to be perpendicular to the bottom to verify the effectiveness of the lumped mass-free field under various sites: underground structures, uniform sites, and layered sites. Finally, the accuracy of the lumped mass-free field boundary was compared with those of the viscoelastic and roller boundaries on different calculation scales, soil damping ratios, structure sizes, and ground motion characteristics. Subsequently, the engineering design values for different damping ratios are given. The results show that the precision of the lumped mass-free field boundary was reasonable, and the operation was simple within the same engineering application.

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Genesis of Kaolinite Deposits in the Jungar Coalfield,NorthChina: Petrological,Mineralogical and Geochemical Evidence     

LIU Linsong  ZHANG Tongjun  LIU Jianping  LIU Qinfu  LI Kuo  LIU Di  LIU Wanyue 《《地质学报》英文版》2021,95(2):517-530

Petrological, mineralogical and geochemical studies carried out on kaolinite deposits in Haerwusu surface mine,Jungar Coalfield, northern Ordos Basin, North China, define their characteristics, ore genesis and economic interest. Based on the crystalline size, two different types of kaolinite rocks, cryptocrystalline and grainy, were identified under the microscope. XRD data show that kaolinite is the predominant mineral, associated with boehmite, magnesite, anatase, pyrite,diaspore and calcite. However, high boehmite content(mean 70%) shows up in the middle layers. Kaolinite minerals present homogeneous shape and a good crystallinity(HI = 0.96–1.26). Geochemical studies show that the SiO2/Al2 O3 molar ratio of kaolinite is close to the theoretical value, and the contents of Na2 O, K2 O, CaO, MgO are less, suggesting a strong chemical weathering environment. The REE and Eu anomalies show a close relationship between kaolinite and the Yinshan Oldland granite. A Ce anomaly reflects a continental sedimentary environment with shallow water. A temperature range of26.7–34℃ was calculated on the basis of the isotopic signatures(δ18 O, δD) of the kaolinite rocks. All these data indicate that the formation of the kaolinite is caused mainly by the dissolution, coagulation, precipitation and recrystallization of aluminosilicate clastics in acidic conditions. The formation of boehmite in the middle layers indicates that the source rocks have changed. Boehmite is mainly formed by dehydration and compaction of an aluminum-rich colloid which transported into peat swamp during diagenesis. In addition, it formed by desiliconization of kaolinite under acidic conditions. Due to its high kaolinite content(up to 90%) and low iron mineral content(less than 1%), and good crystallinity, kaolinite deposits occurred at Haerwusu surface mine probably have great economical value in the future.  相似文献   

南、北盘江流域枯水期水化学特征及离子来源分析   总被引：1，自引：0，他引：1  

马阔  吴起鑫  韩贵琳  董爱国 《中国岩溶》2018,37(2):192-202

为进一步了解珠江上游南、北盘江流域水化学现状,对其枯水期36个河水样品进行水化学特征分析,结果表明:枯水期河水pH值在7.85~8.75之间,呈弱碱性,TDS均值为358 mg·L-1。河水中阴离子组成以HCO3-、SO42-为主,当量浓度占比均值达到65%与26%,阳离子中Ca2+和Mg2+是绝对的优势离子,当量浓度占比均值分别为65%和24%。与丰水期相关研究对比分析发现Ca2+、Mg2+、Na+、SO42-、HCO3-、Cl-的枯水期浓度普遍高于丰水期,K+、NO3-丰、枯水期浓度变化不大。Piper图、岩性端元分析以及离子浓度比值分析表明,研究区水化学主要受碳酸和硫酸共同参与下的碳酸盐岩风化控制。南、北盘江流域都受到农业施用的钾肥和氮肥的影响,此外,北盘江主要受到煤炭开采以及燃煤工业的影响,南盘江主要受到源头及上游河段化工企业废水和沿途市县的生活废水的影响。与前人数据对比发现,15年间人为活动对流域水化学的影响加剧。   相似文献   

An alternative depth-integrated formulation for granular avalanches over temporally varying topography with small curvature     

Yih-Chin Tai  Chih-Yu Kuo  Wai-How Hui 《地球物理与天体物理流体动力学》2013,107(6):596-629

An alternative formulation is proposed for deriving depth-integrated equations for gravity-driven granular avalanches over a non-trivial topography with small curvature. The coordinate system of Bouchut and Westdickenberg (2004 Bouchut, F and Westdickenberg, M. 2004. Gravity driven shallow water models for arbitrary topography. Commun. Math. Sci., 2: 359–389. [Crossref] , [Google Scholar]) is combined with the unified coordinate (UC) method, so that it can evolve in accordance with the entrainment–deposition processes at the basal surface. The resultant mass and momentum equations are formulated as a conservation system of the Cartesian components of the conservative physical variables. The motion of the flows is driven by the basal topography-induced pressure, pressure gradient, and resisted by the basal friction. The best benefit of this formulation is that it greatly simplifies the computation of the varying coordinate orientations. The features and advantages of this formulation are illustrated by the sliding-mass examples where we simulate the motion of a finite mass of granular material sliding down an inclined chute, running through a transition zone, and being deposited onto a horizontal plane.  相似文献   

Spatial interpolation using MLP–RBFN hybrid networks     

I-Cheng Yeh  Yau-Hwang Kuo 《International journal of geographical information science》2013,27(10):1884-1901

It is easy for a multi-layered perception (MLP) to fit a stratified spatial interpolation pattern whose form is close to open surface; while it is easy for a radial basis function network (RBFN) to fit a pocket (radial) spatial interpolation pattern whose form is close to closed surface. However, in the real world, the spatial interpolation pattern may consist of stratified and pocket patterns. Neither MLP nor RBFN can fit the pattern easily. To combine their advantages to fit the complex hybrid spatial interpolation patterns, in this article we propose a novel neural network, MLP–RBFN hybrid network (MRHN), whose hidden layer contains sigmoid and Gaussian units at the same time. Although there are two kinds of processing units in MRHN, in this study we used the principle of minimizing the error sum of squares to derive the supervised learning rules for all the network parameters. This research took rainfall distribution in Taiwan as a case study. The results show that (1) the prediction error of the testing dataset outside the training dataset demonstrated that MRHN was the most accurate among the three networks, RBFN was the next best, and MLP was the worst; (2) the MLP model seriously underestimated the values of high observed rainfall; (3) over-learning may be a serious shortcoming of using RBFN in spatial interpolation applications; (4) MRHN may have better generalization learning capacity than RBFN in spatial interpolation applications.  相似文献   

Locating, monitoring, and characterizing typhoon-linduced landslides with real-time seismic signals   总被引：1，自引：0，他引：1  

Honn Kao  Chih-Wen Kan  Rong-Yuh Chen  Chien-Hsin Chang  Andreas Rosenberger  Tzay-Chyn Shin  Pei-Ling Leu  Kai-Wen Kuo  Wen-Tzong Liang 《Landslides》2012,9(4):557-563

Landslides induced by typhoon Morakot during its passage across Taiwan on 7–9 Aug 2009 claimed more than 700 lives and caused heavy economic loss. Unlike earthquake monitoring, precise locations of landslides could not be determined in near-real time because their seismic phases are difficult to identify. Here, we show that large, damaging landslide events are characterized seismically by a distinct waveform pattern of frequent intermixes of P and S waves over a time window of several tens of seconds. The predominant frequency band during these time windows ranges from 0.5 to 5?Hz. The high-frequency content is clearly deficient relative to that of local earthquakes by about one to two orders. We also demonstrate that large landslide events can be located and monitored with algorithms specifically designed for real-time seismic applications. This near-real-time monitoring capability would be particularly useful for emergency responders and government organizations to coordinate effective relief-and-rescue operations.  相似文献   

内蒙古阿巴嘎旗奥陶纪岩体的发现及地质意义   总被引：4，自引：0，他引：4  

赵利刚  冉皞  张庆红  李承东  王惠初  张阔  许雅雯  侯可军 《世界地质》2012,31(3):451-461

阿巴嘎旗格日敖包岩体位于贺根山断裂带北侧,为一个复式岩体,由石英闪长岩、花岗闪长岩和黑云母二长花岗岩组成,主体为二长花岗岩。采用LA--MC--ICP--MS 锆石U--Pb 定年方法,获得黑云母二长花岗岩206Pb /238U 年龄为449 ± 3. 0 Ma,形成时代为晚奥陶世。岩石为高钾钙碱性系列,轻稀土富集,微量元素Ba、Sr、Nb、Ta 、P、Ti 亏损,Rb 、Th、U、K、Nd、Zr 等元素富集,表明其形成于活动大陆边缘环境。其形成可能与苏尼特左旗南侧俯冲事件有关。  相似文献   

Adjusting Chlorine Dosage and to Prevent Bio‐Growth and Minimize Trihalomethanes in Reverse Osmosis Filtrate in a Wastewater Reclamation Process     

Yi‐Che Hsu  Yu‐Hsuan Wang  Shuo‐Chuan Wu  Chuen‐Mei Wu  Ching‐Ping Chu  Yu‐Jen Chung  Yong‐Tang Huang  Kuo‐Liang Wang 《洁净——土壤、空气、水》2012,40(3):254-261

Feasibility of effluent reclamation for the Futian municipal WWTP in Taichung Taiwan was evaluated using an “SF‐UF‐RO” pilot plant. The optimal parameters of each unit were obtained during the pilot plant test. The pilot plant started the operation in late October 2008 and operated until January 2011. The reverse osmosis (RO) system produces 75 m³ water daily, and the produced water quality was comparable to the city water in Taichung. Chlorine dosed in the sand filtration (SF) inlet and ultrafiltration (UF) backwash had the most significant effect on the stability of system performance. When the chlorine was underdosed, biofilm clogged the bag filter (prefilter of UF) and led to the flow rate decay of the UF. The prefilter needed replacement every 1 or 2 weeks resulting in increased process cost. On the other hand, when the chlorine dosage was increased to mitigate the biofilm growth, the residual chlorine not only reacted with TOC and derived trihalomethanes (THMs) in the RO product water (more than 20 µg/L), but it also damaged the RO membrane. After trial and error, the chlorine concentration was optimized as 0.7 mg/L in SF inlet to prevent growth of biofilm as well as to control the residual chlorine in the RO inlet and THMs in the RO product water. It is suggested that cautiously adjusting chlorine dosage is essential for stably operating such a hybrid membrane system to reclaim the municipal wastewater.  相似文献   

边缘适应：一个适应气候变化新概念的提出     

许吟隆  郑大玮李阔 高新全 《气候变化研究进展》2013,9(5):376-378

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福建省平潭大风分析   总被引：1，自引：0，他引：1  

廖廓  蔡晓禾  王超  吴幸毓 《海洋预报》2012,29(2):64-67

平潭是福建省最大岛屿,处于东亚季风区,是东、西风带交替影响的过度区,其气候季节性特征明显。通过对平潭站1953年建站到2010年的气候资料进行统计分析,结果显示:平潭年大风日数递减趋势明显。通过平潭沿海自动站与本站气象资料对比分析发现,不论是偏北还是偏南风,沿海自动站的风速都大于本站观测值,说明平潭本站风力已经不能真实代表平潭沿海风力。经过仔细研究,进一步总结出平潭本站与沿海自动站风速的相关性,为沿海大风的预报提供科学参考。  相似文献