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Generation and Deformation of Solitary Waves

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china Ocean engineering 1996年第4期11卷 419-432页

作者： Chou Chung-Ren Shih Ruey-Syan Professor, dept. of Harbor and River engineering, national taiwan Ocean university . graduate Student, dept. of Harbor and River engineering, national taiwan Ocean university dept. of Harbor and River Eng. National Taiwan Ocean University

Base on the Lagrangian description and finite differencing of the time step, the generation, propagation and deformation of solitary waves are simulated numerically by means of boundary element method. An algorithm to generate waves with any prescribed form is also implanted in the scheme, but in this research, solitary waves are studied. The numerical model is first verified by studying the case of a solitary wave impinging against a vertical wall. Time histories of evolution of a soliton running up on a sloping beach, as well as over a submerged obstacle are then presented. Applications to scattering problems due to solitary waves progressing over a slope onto a shelf are also shown.

关键词： Lagrangian description solitary wave boundary element method time histories

Properties of Concrete Incorporating Bed Ash from Circulating Fluidized Bed Combustion and Ground Granulates Blast-furnace Slag

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Journal of Wuhan university of Technology(Materials Science) 2011年第2期26卷 348-354页

作者：鄭安 Department of civil engineering National Ilan UniversityIlan 26046TaiwanChina

The properties of concrete incorporating circulating fluidized bed combustion （CFBC） bed ash and ground granulates blast-furnace slag （GGBS） were *** strength,drying shrinkage,mercury intrusion porosimetry （MIP）,scanning electronic microscopy （SEM）,and X-ray diffraction （XRD） of concrete samples containing CFBC bed ash and GGBS were *** work used initial surface absorption test （ISAT） and rapid chloride penetration test （RCPT） on concrete to measure the absorption and the ability of concrete to resist chloride ion characteristics for different concrete samples containing CFBC bed ash and *** circuit potential （OCP）,direct current polarization resistance were obtained to evaluate rebar *** CFBC bed ash was X-ray amorphous and consist of SiO2,Al2O3 and CaO *** the replacement of CFBC for sand increases,the rate of initial surface absorption （ISA） increases but compressive strength *** the content of CFBC bed ash replacement for sand maintains constant,the replacement of GGBS for cement increases,compressive strength increases but the rate of ISA *** and corrosion resistance of rebar significantly improve by utilizing a proper amount of CFBC bed ash and GGBS in concrete.

关键词： corrosion absorption chloride circulating fluidized bed combustion GGBS

NUMERICAL SIMULATION OF TURBIDITY CURRENT IN RESERVOIR

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International Journal of Sediment research 1993年第2期 43-65页

作者： YU, Wei-Sheng Post-Doctoral Fellow, Hydraulic research Laboratory, national taiwan university, taipei 107, taiwan, china LEE, Hong-Yuan Professor, Department of civil engineering, national taiwan university, taipei 107, taiwan, china

Turbidity current is one of the most important phenomena that occurs in a reservoir. It is able to carry tremendous amounts of fine sediment over a long distance and has significant impacts on the spatial distributions of sediment deposition in a reservoir. Layer-inte- integrated equations were applied in this study to simulate the hydraulic characteristics of a gradually varied turbidity current. Small disturbance theory was used to analyze the locations of the boundary conditions, and a series of experiments were conducted to calibrate and verify the model. Sensitivity analyses were also performed to Study the impacts or water entrainment coefficient, total resistance coefficient and transport-capacity concentration of suspended sediment. It was found that supercritical turbidity current occurs when the densimetric Froude number is greater than 0.88, and the boundary conditions have to be as- signed at the upstream end. For the case of the turbidity current without erosion or deposition, variations of the water entrainment coefficient and total resistance coefficient will only change the longitudinal variation rate of the hydraulic characteristics of the turbidity current. For the case of the turbidity current with erosion or deposition, transport-capacity concentration is the only parameter that affects the trend of the turbidity current.

关键词： Turbidity current Reservoir Sedimentation.

Improved performance of GaN-based light-emitting diodes by using short-period superlattice structures

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Progress in Natural Science:Materials International 2010年第1期20卷 70-75页

作者： Yi-jung LIU~1,Chien-chang HUANG~1,Tai-you CHEN~1,Chi-shiang HSU~1,Shiou-ying CHENG~2, Kun-wei LIN~3,Jian-kai LIOU~1,Wen-chau LIU~1 1.Institute of Microelectronics,Department of Electrical engineering,national Cheng-Kung university, Tainan 70101,taiwan,china 2.Department of Electronic engineering,Nation Ilan university,I-Lan 26041,taiwan,china 3.Department and graduate Institute of Computer Science and Information engineering, Chaoyang university of Technology,Taichung 41349,taiwan,china Institute of Microelectronics Department of Electrical Engineering National Cheng-Kung University Tainan 70101 Taiwan China Department of Electronic engineering Nation Ilan University I-Lan 26041 Taiwan China Department and graduate Institute of Computer Science and Information engineering Chaoyang University of Technology Taichung 41349 Taiwan China

An InGaN/GaN multiple-quantum-well（MQW）light-emitting diode（LED）with a ten-period i（undoped）-InGaN/p（Mg doped）-GaN（2.5 nm/5.0 nm）superlattice（SL）structure,was *** SL structure that can be regarded as a confinement layer of holes to enhance the hole injection efficiency is inserted between MQW and p-GaN *** studied LED device exhibits better current spreading performance and an improved quality,compared with a conventional one without SL *** to the reduced contact resistance as well as more uniformity of carriers injection,the operation voltage at 20 mA is decreased from 3.32 to 3.14 V.A remarkably reduced reverse-biased leakage current(10-7-10-9A)and higher endurance of the reverse current pulse are *** measured output power and external quantum efficiency（EQE）of the studied LED are 13.6 mW and 24.8%,respectively. In addition,significant enhancement of 25.4%in output power as well as increment of 5%in EQE for the studied devices is observed, as the studied devices show superior current spreading ability and reduction in dislocations offered by the SL structure.

关键词： GaN superlattice(SL) current spreading hole confinement electrostatic discharge(ESD)

Improved threshold retracker for satellite altimeter waveform retracking over coastal sea

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Progress in Natural Science:Materials International 2006年第7期16卷 732-738页

作者： GUO Jinyun, HWANG Cheiway, CHANG Xiaotao and LIU Yuting ( Department of Land Information and Surveying engineering, Xuzhou Normal university, Xuzhou 221116, china Departmenl of civil engineering, national Chiao Tung university, Hsinchu 30050, taiwan, china Institute of Geodesy, china Academy of Surveying and Mapping, Beijing 100039, china) Xuzhou Normal Univ Dept Land Informat & Surveying Engn Xuzhou 221116 Peoples R China Natl Chiao Tung Univ Dept Civil Engn Hsinchu 30050 Taiwan china Acad Surveying & Mapping Inst Geodesy Beijing 100039 Peoples R China

Data quality is a key factor for the application of satellite altimetry to geodesy and oceanography. Accuracy of altimetry is limited in the coastal area because the altimeter waveforms are seriously contaminated by topography and environmental pollution. So waveform retracking is needed to compute the range correction of geophysical data records (GDRs) for better accuracy. In this paper, a new waveform retracker named the improved threshold retracker (ITR) is put forward. The retracker first builds sub-waveforms based on leading edges detected in a waveform, then determines the middle point of each leading edge to compute the retracking range correction, finally calculates the referenced sea surface heights according to the geoid undulation from a local geopotential model and tide heights from an ocean tide model, and compares it with all retracking ranges to determine the best one. As a test, altimeter waveforms of Geosat/GM are retracked around the taiwan coastal area. The result shows that accuracy of ITR method is two times better than that of theβ-5-pa-rameter function-fitting method and threshold method, and three times better than that of GDRs. ITR can efficiently improve the altimetry accuracy of the coastal sea area.

关键词： satellite altimetry waveform retracking improved threshold retracker sub-waveform.

Wireless neural stimulation using ultrasound

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Wireless neural stimulation using ultrasound

Longshore Current on an Equilibrium Beach

2011年全国压电和声波理论及器件应用研讨会

作者： Paichi Li Department of Electrical and Electronic engineering.graduate School of engineering, national taiwan university,taipei,taiwan

＜正＞Wireless neural stimulation has the potential in several clinical applications such as deep brain stimulation and neuromuscular *** of the existing wireless power and data transmission methods are using electromagnetic waves in the radio frequency ***,the power transmission in this case often has limited *** this study,we propose ultrasound as vehicles for both power and data transmission for wireless,implantable neural *** main advantage is that ultrasound in the MHz range can be focused at dept.,thus providing an effective way for power transmission under FDA safety *** addition,the weak acoustic scattering in soft tissues also allows accurate data communication with the implanted device using *** demonstrate the feasibility,we have designed and fabricated a prototype *** an acoustic power of 112 mW from the transmitting transducer,4.15 mW can be received and made available by the device, which only consumes a power of 1.8 mW for neural stimulation.A BER of 10-6 at 25 kbps data rate is achieved using a modified amplitude shift keying（ASK） *** of ultrasonic wireless neural stimulation is clearly demonstrated.

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来源： cnki会议评论

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china Ocean engineering 1996年第2期11卷 181-192页

作者： Chang Hsien-Kuo and HsuTai-Wen’ Associate Professor, Department of civil engineering, national Chiao Tung university, 1001 Ta-Hsueh Rd.,Hsinchu, 300 taiwan . Associate Professor, Department of Hydraulics and Ocean engineering, national Cheng Kung university,Tainan Department of civil engineering National Chiao Tung University 1001 Ta-Hsueh Rd. Hsinchu 300 Taiwan dept. of Hydr. and Ocean engineering National Cheng Kung University Tainan Taiwan

Natural beaches tend to be concave-up rather than planar and are reasonable to be modeled by an equilibrium beach profile. A governing equation for longshore current on an equilibrium beach is derived and its analytical solution is given in this paper. Through comparisons of the present solution and field data of longshore current for a step-type beach, the present solution is found to have fairly agreeable prediction to longshore current inside the surf zone. The effects of the shape of a concave-up beach and turbulent mixing stress on longshore current inside the surf zone are discussed in the present paper.

关键词： longshore current equilibrium beach profile surf zone turbulent mixing stress

NUMERICAL MODELLING OF ROCK FALL USING EXTENDED DDA

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岩石力学与工程学报 2003年第6期22卷 926-931页

作者： Chen Guangqi (graduate School of civil and Structural engineering, Kyushu university, Fukuoka 816-8581 Japan) graduate School of civil and Structural engineering Kyushu University 日本 Fukuoka

The reasonable design of protective structures to mitigate the hazards from rock fall depends on the knowledge of motion behaviors of falling stones,such as the falling paths,velocities,jump heights and *** simulation is an effective way to gain such kind of knowledge,In this paper,the discontinuous deformation analysis (DDA) is applied to rock fall *** order to obtain more reliable results,the following improvements and extensions are made on the original DDA.(1)Solve the problem of block expansions due to rigid body rotation error.(2) Add the function of modeling the drag resistance from air and plants so that the velocities of falling stones obtained by simulations are good enough in agreement with those by experiments in situ.(3)Add the capability to consider energy loss due to block collisions so that the jumping heights and distances obtained by simulations are good enough in agreement with thos by experiments even for the slope with very soft layer on its *** of application examples is presented to show that the extended DDA is very effective and useful in rock fall ***,the presented method is expected to be put into wide use in slop stability analysis.

关键词：岩石力学 DDA 落石运动岩石力学能量损耗 DDA 边坡

A SIMPLIFIED WATER QUALITY MODEL FOR WETLANDS

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International Journal of Sediment research 2004年第2期19卷 96-105页

作者： Jan-Tai KUO, Jihn-Sung LAI, Wu-Seng LUNG and Chou-Ping YANG Professor, Department of civil engineering and Hydrotech research Institute, national Tawan university, No. 1, Sect. 4, Roosevelt Road, taipei 106, taiwan E-mail: kuoj@ntu.edu.tw assistant researcher, Hydrotech research Institute, national taiwan university, taipei 106, taiwan Professor, Department of civil engineering, university of Virginia, Charlottesville, Virginia 22904-4742, U.S.A Ph.D. Candidate, Department of civil engineering, national taiwan university,taipei 106, taiwan Department of civil engineering and Hydrotech research Institute National Taiwan UniversityNo.1Sect.4Roosevelt RoadTaipei 106TaiwanChina Hydrotech research Institute National Taiwan UniversityTaipei 106TaiwanChina Department of civil engineering University of VirginiaCharlottesvilleVirginia 22904-4742U.S.A Department of civil engineering National Taiwan UniversityTaipei 106TaiwanChina

The purpose of this study is to develop a simplified mathemirtical model to simulate suspendedsolids and total phosphorus concentrations in a wetland or detention pond. Field data collectedfrom a wet detention pond during storms were used to demonstrate the application of this *** agreements between the model results and data were achieved. The ratio of averagoutlet method and summary of loads method were used to quantify the removal efficiency ofpollutants, reflecting the efficiencies are very close. The results of this study can be used fornonpoint source pollution control, wastewater treatment or best management practices (BMPs)through the wetland.

关键词： Wetland Detention pond Water quality model Nonpoint source pollution control BMPs