Observational properties of accretion discs: Precessing and warped?     

Phil Charles  Will Clarkson  Remon Cornelisse  Chun Shih I 《New Astronomy Reviews》2008,51(10-12):768

Over the last 40 years, X-ray astronomy missions have revealed long-term, superorbital periods in a variety of X-ray binaries. These modulations can provide significant constraints on the physical properties of accretion discs. Some of these modulations are Her X-1-like and are interpreted as irradiation-driven, tilted, precessing accretion discs. Others show more complex light curves, with the period changing on timescales >1000 d, and are interpreted in terms of the Ogilvie and Dubus [Ogilvie, G.I., Dubus, G., 2001, MNRAS 320, 485 (OD01)] disc stability criteria. We suggest a categorisation of superorbital periods into six different types, based on their observed characteristics.  相似文献   

Sea level fluctuations on the east coast of Taiwan that overlie continental shelf break     

David Ching-Fang Shih  Yue-Gau Chen  Gwo-Fong Lin  Yih-Min Wu  Yee-Ping Jia  Chih-Ming Ma 《Stochastic Environmental Research and Risk Assessment (SERRA)》2010,24(1):29-46

Captured CO₂ could be deliberately injected into the ocean at great depth, where most of it would remain isolated from the atmosphere for centuries. CO₂ can be transported via pipeline or ship for release in the ocean or on the sea floor. No matter what for medium depth or deep sea, it appears that a potential area exists between 122–122.5°E and 21.8–22.3°N for CO₂ sequestration. The east coast of Taiwan can be a candidate for CO₂ temporary storage or transmitted plant. To have whole picture of assessment of sea level fluctuation, a completed statistical summary of seasonal sea level at six tidal gauge stations along the east coast of Taiwan is provided herein. Seasonal sea level time series is analyzed using spectral analysis in frequency domain to identify periodic component and phase propagation, especially for the astronomical-driven tidal effects. It identifies that the semi-diurnal and diurnal components in the resultant time series are related to astronomical tides M₂, and K₁ and O₁, respectively. It demonstrates a full analysis of sea level variations, and results can be useful when construction of testing or operating facilities on sea surface becomes desirable in the future.  相似文献   

Wind characterization and potential assessment using spectral analysis   总被引：2，自引：2，他引：0  

David Ching-Fang Shih 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(2):247-256

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关于长江正源的确定问題   总被引：1，自引：1，他引：0  

石铭鼎 《地理研究》1983,2(1):23-34

江源水系诸河,地处青藏高原腹地,因人迹罕至,对那条河是长江正源,历史上并没有一个统一的认识可以遵循。通过考察后,在江源诸河中,论长度,沱沱河(包括源头冰川)最长,当曲稍次;论河道上下游的一致性,尕尔曲最顺,沱沱河其次;而论水量,当曲最丰,沱沱河其次。综合以上因素,我们认为沱沱河长度既长,方向又顺,应为长江正源。综合上述观点,我们算得:由沱沱河源至四川省宜宾,长3474公里;宜宾至长江口约为2806公里。由于长江中下游下流主泓经常摆动,入海口段已有相当延长,故长江全长约为6300公里。  相似文献   

Optimal Thresholding of Predictors in Mineral Prospectivity Analysis     

Baddeley  Adrian  Brown  Warick  Milne  Robin K.  Nair  Gopalan  Rakshit  Suman  Lawrence  Tom  Phatak  Aloke  Fu  Shih Ching 《Natural Resources Research》2021,30(2):923-969

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Spectral decomposition of periodic ground water fluctuation in a coastal aquifer     

David Ching‐Fang Shih  Gwo‐Fong Lin  Yee‐Ping Jia  Yue‐Gau Chen  Yih‐Min Wu 《水文研究》2008,22(12):1755-1765

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Does canopy wetness matter? Evapotranspiration from a subtropical montane cloud forest in Taiwan          下载免费PDF全文

Hou‐Sen Chu  Shih‐Chieh Chang  Otto Klemm  Cheng‐Wei Lai  You‐Zhu Lin  Chi‐Chen Wu  Ji‐Yu Lin  Jhia‐Ying Jiang  Jiquan Chen  Johan F. Gottgens  Yue‐Joe Hsia 《水文研究》2014,28(3):1190-1214

Evapotranspiration (ET) and canopy wetness were measured over a 2‐year intensive field campaign at the Chi‐Lan Mountain cloud forest site in Taiwan. Eddy covariance and sap flow methods were applied to measure ET and tree sap flow of the endemic yellow cypress (Chamaecyparis obtusa var. formosana). ET was 553 mm yr^?1 over the study period with an annual rainfall and fog deposition of 4893 and 288 mm yr^–1, respectively. The duration of canopy wetness exceeded actual fog or rain events (mostly in the afternoon), and the intercepted water was evaporated later in the following dry morning. The cumulative wet duration accounted for 52% of time over the study period, which was longer than the duration of rainfall and fog altogether (41%). As it adapted to the extremely moist environment, the yellow cypress behaved in a wet‐enhanced/dry‐reduced water use strategy and was sensitive to short periods of dry atmosphere with high evaporation potential. During dry days, the sap flow rate rose quickly after dawn and led to conservative water use through midday and the afternoon. During periodically wet days, the canopy was mostly wetted in the morning, and the interception evaporation contributed largely to the morning ET. The initiation of morning sap flow was postponed 1–3 h, and the sap flow rate tended to peak later at midday. The midday canopy conductance was higher in the periodically wet days (10.6 mm s^–1) as compared with 7.6 mm s^?1 in the dry days. Consequently, the dry‐reduced water use strategy led to much lower annual ET with respect to the available energy (~46%) and high precipitation input (~11%). The moist‐adapted ecohydrology we report reveals the vulnerability of montane cloud forests to prolonged fog‐free periods. More research is urgently needed to better understand the resilience of these ecosystems and formulate adaptive management plans. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

A two‐dimensional inverse model to identify transmissivity in an anisotropic aquifer     

Shih‐Ching Wu  Yih‐Chi Tan  Chu‐Hui Chen  Shien‐Tsung Lin  Kai‐Yuan Ke 《水文研究》2008,22(26):5086-5096

This study suggested a numerical model using the Tabu search algorithm along with the Adjoint State method to identify the hydrogeological characteristics of an anisotropic groundwater aquifer. The Tabu search algorithm was applied to identify the anisotropic transmissivity components to avoid a local optimum. Then, the Adjoint State method was used to calculate the sensitivity of the parameters in order to increase the efficiency of the optimization. For an anisotropic and homogeneous aquifer, results showed that the optimal procedure presented combining the Tabu search algorithm and the Adjoint State method might successfully identify the values of the transmissivity components. If the duration of the pumping test was long enough (12‐h pumping test), the value of the transmissivity components could be optimized with type‐curve, straight‐line, and Tabu search methods, along with the Adjoint State methods. If the duration of the pumping test was short (0·5‐h pumping test), the Tabu search method, along with the Adjoint State method proposed herein, might successfully optimize the transmissivity components. For an anisotropic but heterogeneous aquifer, results showed that the suggested optimal procedure still successfully identified the values of the transmissivity components. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Using Lego NXT to explore scientific literacy in disaster prevention and rescue systems   总被引：4，自引：4，他引：0  

Bih-Yaw Shih  Chen-Yuan Chen  Chung-Wei Chen  I Hsin 《Natural Hazards》2012,64(1):153-171

This study explores the effectiveness of disaster prevention programs using NXT control techniques. The purpose of the cultivation of scientific literacy is to develop a more rational, scientific perspective on the current social changes and the impact of natural disasters. Using NXT as an effective scientific tool to support science education, we can further explore science education for the development of scientific literacy. The expectation confirmation model and technology acceptance model are used to explain the effect of technology products on the user??s satisfaction and intention. However, for the interpretation of scientific literacy, there is a lack of environmental and cognitive factors. So we combine social cognitive theory with social and scientific theories in our exploration of the use of NXT for the dominant effect of scientific literacy. The results demonstrate that users?? self-efficacy and the ease of use of NXT have low significance on use of scientific tools, but, at the end, it did not affect the user wishes. The interactions of NXT features and climate are the main causes of enhanced user intentions. Therefore, environmental factors are identified as an important reason for the development of scientific literacy. The results of this study on scientific literacy stimulate more directions for discussion.  相似文献   

Disaster prevention and reduction for exploring teachers’ technology acceptance using a virtual reality system and partial least squares techniques   总被引：8，自引：8，他引：0  

Chen-Yuan Chen  Bih-Yaw Shih  Shih-Hsien Yu 《Natural Hazards》2012,62(3):1217-1231

This study explores the effectiveness of disaster prevention programs using virtual reality and partial least squares techniques. The purpose is to gain an understanding of IS (information system) usage and acceptance behaviors, mainly the users’ acceptance of virtual reality, as well as provide a reference for future disaster prevention programs. Virtual reality is an important part of this process and needs a lot of special skills like knowledge of software and hardware for its development. To date, virtual reality has been used in many ways, such as in movies, for medical treatment and for educational training. This model incorporates the technology acceptance model, technology acceptance model 2 and IS success model and uses the partial least squares technique for structural modeling. The results indicate that virtual reality learning self-efficacy, subjective norms, system quality, information quality and service quality have a significant influence on perceived usefulness, perceived ease of use and playfulness. Considering the users’ intention to use and attitude while using virtual reality, playfulness is more significant than either perceived usefulness or perceived ease of use.  相似文献