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Acta Mathematica Sinica,English Series 2000年第2期16卷 261-270页

作者： Shaoyi Zhangdepartment of Mathematics.beijing Normal university,beijing 100875,p.r.china department of Mathematics,Hubei Normal university,Huangshi 435002,p.r.china department of Mathematics Beijing Normal University Beijing 100875 P. R. China department of Mathematics Hubei Normal University Huangshi 435002 P. R. China

In this paper,for two given transition probabilities,the existence of the optimal Markovian coupling with respect to a non-negative lower semi-continuous function is *** an application of this result,the well-known Strassen’s theorem is ***,it is proved that the existence of an order-preserving Markovian coupling of two given jump processes is equivalent to their stochastical comparability.

关键词： Transition probability Markovian coupling Jump process

THE EXISTENCE OF rADIAL LIMITS OF ANALYTIC FUNCTIONS IN BANACH SpACES

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Chinese Annals of Mathematics,Series B 2001年第4期22卷 513-518页

作者： BU SHANGQUAN department of Applied Mathematics, tsinghua university, beijing 100084, china. E-mail: sbu@*** department of Applied Mathematics Tsinghua University Beijing 100084 China

Let X be a complex Banach space without the analytic radon-Nikodym property. The author shows that G = {f∈H∞(D,X) there exists∈＞ 0, such that for almost allθ∈[0, 2], lim sup f(reiθ) - f(seiθ)≥∈ } is a dense open subset of H∞(D, X). It is also shown that for every open subset B of T, there exists F∈H∞ (D, X), such that F has boundary values everywhere on Bc and F has radial limits nowhere on B. When A is a measurable subset of T with positive measure, there exists f∈H∞ (D, X), such that f has nontangential limits almost everywhere on Ac and f has radial limits almost nowhere on A.

关键词： Analytic radon-Nikodym property radial limits and vector-valued Hardy space

Constraints on Cardassian universe from Gamma ray bursts

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Science china(physics,Mechanics & Astronomy) 2010年第9期53卷 1720-1725页

作者： WANG TaiShan1 & LIANG Nan2 1 department of physics & Center for Astrophysics,tsinghua university,beijing 100084,china 2 department of Astronomy,beijing Normal university,beijing 100875,china 1. department of physics & Center for Astrophysics Tsinghua University Beijing 100084 China2. Department of Astronomy Beijing Normal University Beijing 100875 China

Constraints on the original Cardassian model and the modified polytropic Cardassian model are examined from the recently derived 42 gamma-ray bursts(GrBs) data calibrated with the method that can avoid the circularity *** results show that GrBs can be an optional observation to constrain the Cardassian *** the GrBs data with the newly de-rived size of baryonic acoustic oscillation peak from the Sloan Digital Sky Survey(SDSS),and the position of the first acoustic peak of the Cosmic Microwave Background radiation(CMB) from Wilkinson Microwave Anisotropy probe(WMAp),we find Ωm0=0.27+0.02-0.02,n=0.06+0.07-0.08(1σ) for the original Cardassian model,and Ωm0=0.27+0.23-0.02,n=-0.09+0.23-1.91,β=0.82+2.10-0.62(1σ) for the modified polytropic Cardassian model.

关键词： Cardassian Gamma ray burst Cosmic Microwave Background baryonic acoustic oscillation

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, beijing 100084, 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, beijing 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, beijing 100084, 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 university,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, beijing 100084, 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

New evidence for lack of CMB power on large scales

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Science china(physics,Mechanics & Astronomy) 2010年第3期53卷 567-570页

作者： LIU Hao1 & LI Tipei1,2,3 1 Key Laboratory of particle Astrophysics, Institute of High Energy physics, Chinese Academy of sciences, beijing 100049, china 2 department of physics & Center for Astrophysics, tsinghua university, beijing 100084, china 3 department of Engineering physics & Center for Astrophysics, tsinghua university, beijing 100084, china 1. Key Laboratory of particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China2. Department of Physics & Center for Astrophysics Tsinghua University Beijing 100084 China3. Department of Engineering Physics & Center for Astrophysics Tsinghua University Beijing 100084 China

A digitalized temperature map is recovered from the first light sky survey image published by the planck team, from which an angular power spectrum of the cosmic microwave background (CMB) is derived. The amplitudes of the low multipoles (low-l) measured from the preliminary planck power spectrum are significantly lower than those reported by the WMAp team. possible systematical effects are far from enough to explain the observed low-l differences.

关键词： cosmology cosmic microwave background data analysis

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, beijing 100084, 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.