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Droplet creator based on electrowetting-on-dielectric for lab on a chip

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Science china(Technological Sciences) 2006年第2期49卷 248-256页

作者： ZENG Xuefeng1, YUE Ruifeng1, WU Jiangang1, HU Huan1, DONG Liang1, WANG Zheyao1, HE Feng2.& LIU Litian1 1. Institute of Microelectronics, tsinghua university, beijing 100084,{2. 2. department of Engineering Mechanics, tsinghua university, beijing 100084,{2. 1. Institute of Microelectronics Tsinghua University Beijing 100084 China 2. department of Engineering Mechanics Tsinghua University Beijing 100084 China

Electrowetting-on-dielectric (EWOD) is to directly control the wettability of liquids on the solid surface by applying the electric potential to the microelectrode array under the dielectric layer. The prototype of the EWOD droplet creator with the sandwiched structure is used: the droplet is sandwiched between the top and bottom plates; the bot- tom plate consists of silicon used as the substrate of the microelectrode array, nitride sili- con film deposited by low pressure chemical vapor deposition as the dielectric layer and the fluorocarbon polymer film deposited by inductively coupled plasma chemical vapor deposition as the hydrophobic layer; and the top plate is the transparent electrode covered with the hydrophobic layer. To obtain the required minimum voltage, the process and the criterion of creating droplets are analyzed. At the voltage of 35 V the deionized water droplet surrounded in silicone oil is successfully created.

关键词： micro total analysis system, electrowetting-on-dielectric, creation and control of droplets, inductively coupled plasma chemical vapor deposition.

Ultra-Broad-Band LiNbO3 Electro-Optic Modulators with Novel Complex Electrode

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Chinese Journal of Lasers 2000年第2期9卷 128-133页

作者： ZHOU Weiqin WU Boyu PENG Jihu GU Jinghua HU Jinyang (department of Electronic Engineering, tsinghua university,{2., china) 清华大学北京 100084

The characteristics of Z- cut LiNbO3optical modulators with novel complex electrode are discussed by using the finite element method （FEM） and studied experimentally in this paper. The travelling wave electrode consists of upper and lower parts. It can easily realize phase velocity matching between microwave and optical wave and drastically reduce microwave electrode loss. An electrooptic modulator with larger than 100 GHz bandwidth and half wave voltage 6 V is designed, fabricated and measured. Vπis 5. 1 V and the attenuation coefficient ac is 0. 3 dB/(cm· GHz1/2.. The experimental results show that the modulator has great potentiality for expanding bandwidth.

关键词： electro-optic medulator LiNbO3 modulator travelling wave electrode complex electrode

Computational intelligence:From mathematical point of view

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Chinese Science Bulletin 1999年第10期44卷 865-880页

作者： QIAN Minping and GONG Guangludepartment of Probability and Statistics, Peking university, {2. 100871, china department of Applied Mathematics, tsinghua university, beijing 100084, china Deportment of Probability and Statistics Peking University Beijing China department of Applied Mathematics Tsinghua University Beijing China

A simple but illustrative survey is given on various approaches of computational intelligence with their features, applications and the mathematical tools involved, among which the simulated annealing, neural networks, genetic and evolutionary programming, self-organizing learning and adapting algorithms, hidden Markov models are recommended intensively. The common mathematical features of various computational intelligence algorithms are ***, two common principles of concessive strategies implicated in many computational intelligence algorithms are discussed.

关键词： computational intelligence simulated annealing neural network genetic algorithm evolutionary program-ming self-organizing learning self-adapting algorithm hidden Markov model concession strategy.

CO_2.Mitigation in Coal Gasification Cogeneration Systems with Integration of the Shift Reaction, CO_2.Absorption and Methanol Production

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Journal of Thermal Science 2004年第3期13卷 193-198页

作者： Yuanyuan DUAN Jin ZHANG Key Laboratory of Thermal Science and Power Engineering, department of Thermal Engineering, tsinghua university,{2., china Key Laboratory of Thermal Science and Power Engineering Department of Thermal Engineering Tsinghua University Beijing China

Cogeneration of electricity and liquid fuel can achieve higher efficiencies than electricity generation alone in Integrated Gasification Combined Cycle (IGCC), and cogeneration systems are also expected to mitigate CO2.emissions. A proposed methanol-electricity cogeneration system was analyzed in this paper using exergy method to evaluate the specified system. A simple cogeneration scheme and a complicated scheme including the shift reaction and CO2.removal were compared. The results show that the complicated scheme consumes more energy, but has a higher methanol synthesis ratio with partial capture of *** those methanol and electricity cogeneration systems, the CO2.mitigation is not merely an additional process that consumes energy and reduces the overall efficiency, but is integrated into the methanol production.

关键词： cogeneration system methanol synthesis CO2 mitigation exergy analysis

Experimental studies on removal of carbon dioxide by aqueous ammonia fine spray

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Science china(Technological Sciences) 2010年第1期53卷 117-122页

作者： NIU ZhenQi,GUO YinCheng & LIN WenYi department of Engineering Mechanics,School of Aerospace,tsinghua {2.,beijing 100084,china 1. department of Engineering Mechanics School of Aerospace Tsinghua University Beijing 100084 China

Experimental studies on carbon dioxide capture in a spray scrubber were carried *** spray of aqueous ammonia was used as CO2.*** of different operating and design parameters on CO2.removal efficiency including concentration of aqueous ammonia,liquid flow rate,total gas flow rate,initial temperature and concentration of carbon dioxide were investigated.

关键词： carbon dioxide aqueous ammonia absorption removal efficiency fine spray

Measurement of Mean Burst Period in WallTurbulence by Wavelet Analysis

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Communications in Nonlinear Science and Numerical Simulation 1999年第3期4卷 3-5页

作者： Li LI Chunxiao XU Zhaoshun ZHANG and Guialang CUI(department of Engineering Mechanics, tsinghua university,{2., china) department of Engineering Mechanics Tsinghua University Beijing 100084 China

IntroductionInwallturbulence,theejectionoflow-speedfluidfromthewallandthesweepofth***urst,andwhentheflowisbursting,therealwaysea... 详细信息

IntroductionInwallturbulence,theejectionoflow-speedfluidfromthewallandthesweepofth***urst,andwhentheflowisbursting,therealwaysea...

关键词： turbulence burst phenomena wavelet analysis

Effect of acid oxidization of carbon nanotube electrode on the capacitances of double layer capacitors

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Science china(Technological Sciences) 2004年第3期47卷 257-264页

作者： Li Chensha1,WANG Dazhi1,LIANG Tongxiang2.WANG Xiaofeng1 & LIANG Ji1 1. department of Mechanical Engineering, tsinghua university,{2. 100084, china 2. Institute of Nuclear Energy Technology, tsinghua university,Beijng 102.01,china tsinghua Univ Dept Mech Engn Beijing 100084 Peoples R China tsinghua Univ Inst Nucl Energy Technol Beijing 102201 Peoples R China

Polarizable electrode of electric double layer capacitor was made from carbon nanotubes. The effect of acid oxidation of electrode on the specific capacitance was studied. Oxidation removed the redundant carbon, expanded the pore size and introducedf some kinds of functional groups on the surface of CNTs. The specific capacitance of the electrodes winth organic electrolyte was increased from 2..4 to 49.6 F/g after being oxidized at a volume ratio H2.O4 to HNO3 of 3:1.

关键词： carbon nanotubes, electric double layer capacitor, specific capacitance.

TWO-DIMENSIONAL SIMULATION OF FLOWS IN PLANE-WALL DIFFUSERS

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Journal of Hydrodynamics 1992年第4期4卷 43-53页

作者： Yuan Ming-shun department of Hydraulic Engineering,tsinghua {2.,beijing 100084,P.R.china

A numerical model has been developed for computing turbulent flow in plane-wall *** model solves the weakly compressible flow equations with the application of the Smagorinsky's subgrid-scale turbulence model and the boundary conditions of partial slip and no slip at the solid *** examples include two-dimensional calculations of unstalled and stalled flows in diffusers of small diverging angle,as well as transitory stall flow in a symmetric diffuser of 16°total *** the unstalled and stalled flows,the calculated pressure recovery and velocity profile are compared with experimental *** the transitory stall flow,the com- putational result shows the unsteady flow features including the vortex shedding and stall washout phenomena that have been experimentally observed.

关键词： diffuser turbulent flow separation transitory stall Large-eddy simulation

Application of the wavelet transforms on axial strain calculation in ultrasound elastography

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Progress in Natural Science:Materials International 2006年第9期16卷 942-947页

作者： LUO Jianwen, BAI Jing and SHAO Jinhua (department of Biomedical Engineering, School of Medicine, tsinghua university,{2., china) [a]department of Biomedical Engineering School of Medicine Tsinghua University Beijing China

In ultrasound elastography, the axial strain distribution within biological tissues is calculated as the numerical derivative (differentiation) of the estimated axial displacement field. Unfortunately, the numerical derivative is unstable because it can greatly amplify the noises, especially at high frequencies. This work focuses on the axial strain calculation from the estimated axial displacements using wavelet transforms (WTs), including continuous wavelet transforms (CWTs) and discrete wavelet transforms (DWTs). The feasibility of the WT-based method using the quadratic spline function is verified by computer simulations and some phantom data. Results indicate that the WT-based method can effectively reduce the noise amplification in axial strain calculation.

关键词： ultrasound elastography axial strain differentiation wavelet transforms.