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31.
Kinmen Island is a small, tectonically stable, granitic island that has been suffering from a scarcity of fresh water resources due to excessive annual evapotranspiration over annual precipitation. Recent studies further indicate that shallow (0–70 m) sedimentary aquifers, the major sources of groundwater supply, have already been over-exploited. Therefore, this preliminary study is to investigate the existence of exploitable water resources that can balance the shortage of fresh water on this island. Site characterization data are obtained from island-wide geophysical surveys as well as small-scale tests performed in a study area formed by three deep (maximum depth to 560 m) vertical boreholes installed in mid-east Kinmen northeast to Taiwu Mountain. Vertical fracture frequency data indicate that the rock body is fractured with a spatially correlated pattern, from which three major fracture zones (depths 0–70, 330–360, and below 450 m) can be identified. Geologic investigations indicate that the deepest fracture zone is caused by the large-scale, steeply dipping Taiwushan fault. This fault may have caused a laterally extensive low-resistivity zone, a potential fractured aquifer, near Taiwu Mountain. The middle fracture zone is induced by the Taiwushan fault and intersects the fault approximately 21 m southeast of the study area below a depth of 350 m. Slug testing results yield fracture transmissivity varying from 4.8 × 10−7 to 2.2 × 10−4 m2/s. Cross-hole tests have confirmed that hydraulic connectivity of the deeper rock body is controlled by the Taiwushan fault and the middle fracture zone. This connectivity may extend vertically to the sedimentary aquifers through high-angle joint sets. Despite the presence of a flow barrier formed by doleritic dike at about 300 m depth, the existence of fresh as well as meteoric water in the deeper rock body manifests that certain flow paths must exist through which the deeper fractured aquifers can be connected to the upper rock body. Therefore, groundwater stored within the Taiwushan fault and the associated low-resistivity zone can be considered as additional fresh water resources for future exploitation.  相似文献   
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The use of base isolation for enhancing seismic resistibility has been proven as an efficient method in experimental and theoretical studies. It is usual to insert a flexible device in the horizontal direction to permit the most of relative deformation of a structure at this level. Because the rigidity of the superstructure is much higher than that of the base isolator underneath the structure, the behavior of the superstructure can be idealized as a rigid body during earthquakes. In general, hundreds of degrees of freedom and a step‐by‐step time history analysis are the basic requirements for calculating the seismic response of a base‐isolated structure under earthquakes. In order to develop a simple tool which can be easily adopted for calculating the seismic responses of the spherical sliding type isolated structures, a piecewise exact solution for predicting the seismic responses of base‐isolated structures has been derived in this study. The comparison between the experimental results conducted at the National Center for Research on Earthquake Engineering (NCREE) in Taiwan and the analytical results obtained from the piecewise exact solution show that the formulation derived in this study can predict the seismic responses of the base‐isolated structure with a very high accuracy. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
35.
An earthquake early warning (EEW) system with integration of regional and onsite approaches was installed at nine demonstration stations in several districts of Taiwan for taking advantages of both approaches. The system performance was evaluated by a 3-year experiment at schools, which experienced five major earthquakes during this period. The blind zone of warning was effectively reduced by the integrated EEW system. The predicted intensities from EEW demonstration stations showed acceptable accuracy compared to field observations. The operation experience from an earthquake event proved that students could calmly carry out correct action before the seismic wave arrived using some warning time provided by the EEW system. Through successful operation in practice, the integrated EEW system was verified as an effective tool for disaster prevention at schools.  相似文献   
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Digital mobile mapping, the method that integrates digital imaging with direct geo-referencing, has developed rapidly over the past 15 years. The Kalman filter (KF) is considered an optimal estimation tool for real-time INS/GPS integrated kinematic positioning and orientation determination. However, the accuracy requirements of general mobile mapping applications cannot be easily achieved even when using the KF scheme. Therefore, this study proposes an intelligent scheme combining ANN and RTS backward smoother to overcome the limitations of KF and to enhance the overall accuracy of attitude determination for tactical grade and MEMS INS/GPS integrated systems.
Yun-Wen Huang (Corresponding author)Email:
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In our attempt to characterize the interaction of trophic coupling between Synechococcus and pigmented nanoflagellates (PNFs), successive size-fraction experiments were performed at a coastal station on the northeast coast of Taiwan from June, 2005 to January, 2006. By estimating the growth rate and grazing rate of Synechococcus in the presence of nanoflagellates of different sizes, we truncated the food web by removing organisms with different body sizes (<2 μm, <5 μm, <10 μm, and <20 μm). The growth rates of Synechococcus ranged from −0.016 to 0.051 h−1 during the experimental period, suggesting that temperature was a primary mechanism controlling Synechococcus growth. In addition to size and relative biomass of pigmented nanoflagellates and Synechococcus, it is suggested that community structures played an important role in trophic link. Furthermore, we conclude that the trophic cascading effect in the northeast coast of Taiwan includes: 1) high grazing rates at night in the warm season; 2) the Synechococcus biomass generally exceeds the grazing threshold (6 × 104 cells mL−1); and 3) the biomass ratio of <5 μm PNFs to >5 μm PNFs should be 1:1 to 2:1.  相似文献   
38.
We investigate the causes for a strong high latitude imposed ice (land or sea) influence on the marine Intertropical Convergence Zone (ITCZ) in the Community Climate Model version 3 coupled to a 50-m slab ocean. The marine ITCZ in all the ocean basins shift meridionally away from the hemisphere with an imposed added ice cover, altering the global Hadley circulation with an increased tropical subsidence in the hemisphere with imposed ice and uplift in the other. The effect appears to be independent of the longitudinal position of imposed ice. The anomalous ice induces a rapid cooling and drying of the air and surface over the entire high- and midlatitudes; subsequent progression of cold anomalies occurs in the Pacific and Atlantic northeasterly trade regions, where a wind-evaporation-sea surface temperature (SST) feedback initiates progression of a cold SST ‘front’ towards the ITCZ latitudes. Once the cooler SST reaches the ITCZ latitude, the ITCZ shifts southwards, aided by positive feedbacks associated with the displacement. The ITCZ displacement transports moisture away from the colder and drier hemisphere into the other hemisphere, resulting in a pronounced hemispheric asymmetric response in anomalous specific humidity; we speculate that the atmospheric humidity plays a central role in the hemispheric asymmetric nature of the climate response to high latitude ice cover anomalies. From an energy balance viewpoint, the increased outgoing radiative flux at the latitudes of the imposed ice is compensated by an increased radiative energy flux at the tropical latitudes occupied by the displaced ITCZ, and subsequently transported by the altered Hadley and eddy circulations to the imposed ice latitudes. The situation investigated here may be applicable to past climates like the Last Glacial Maximum where hemispheric asymmetric changes to ice cover occurred. Major caveats to the conclusions drawn include omission of interactive sea ice physics and ocean dynamical feedback and sensitivity to atmospheric physics parameterizations across different models.  相似文献   
39.
The Fourier transform of cosmological density perturbations can be represented in terms of amplitudes and phases for each Fourier mode. We investigate the phase evolution of these modes using a mixture of analytical and numerical techniques. Using a toy model of one-dimensional perturbations evolving under the Zel'dovich approximation as an initial motivation, we develop a statistic that quantifies the information content of the distribution of phases. Using numerical simulations beginning with more realistic Gaussian random-phase initial conditions, we show that the information content of the phases grows from zero in the initial conditions, first slowly and then rapidly when structures become non-linear. This growth of phase information can be expressed in terms of an effective entropy. Gaussian initial conditions are a maximum entropy realization of the initial power spectrum; gravitational evolution decreases the phase entropy. We show that our definition of phase entropy results in a statistic that explicitly quantifies the information stored in the phases of density perturbations (rather than their amplitudes), and that this statistic displays interesting scaling behaviour for self-similar initial conditions.  相似文献   
40.
A critical concern regarding river bed stabilization and river engineering is the short‐term general scour that occurs in a field setting far from a river‐crossing structure or embankment during a typhoon‐induced flood. This study investigated the improvement of existing techniques that have been used to measure river bed scour. One of these techniques is the numbered‐brick column or scour chains method, in which only the maximum general scour depth of river bed is observed. A wireless tracer for monitoring real‐time scour was set‐up with a numbered‐brick column and was employed to collect synchronous data. The proposed method was successfully used to observe both real‐time scour and the maximum depth at flood peak. This observation was conducted at a steep gravel‐bed reach of the Shuideliaw Embankment on the intermittent Choshui River in Central Taiwan during Typhoon Soulik, which occurred in 2013. Future studies must be conducted to complete the development of an automatic real‐time scour and flood monitoring system for use in severe weather and flow conditions; this would facilitate the identification of river bed scour during conditions of unstable flow and the improvement of flood prevention engineering, bridge closure detection and emergency evacuation procedures. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
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