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Influence of magnetic current on the ground state entanglement in an isotropic transverse XY chain

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Progress in Natural Science:Materials International 2007年第10期17卷 1147-1151页

作者： Liu Dan1,2., Zhang Yong3 and Long Guilu1,2.1. key laboratory for Atomic and Molecular NanoSciences, and Department of Physics, {2., {2., China 2. Center of Quantum Information Science and Technology, tsinghua National laboratory for information Science and Technology, {2., China 3. Institute of Physics, School of Sciences, beijing university of Posts and Telecommunications, beijing 100876, China) key laboratory for Atomic and Molecular NanoSciences and Department of Physics Tsinghua University Beijing 100084 China Center of Quantum Information Science and Technology Tsinghua National Laboratory for information Science and Technology Beijing 100084 China Institute of Physics School of Sciences Beijing University of Posts and Telecommunications Beijing 100876 China

We study the ground state entanglement in a three-qubit XY chain under the influence of a magnetization current. It is found that the ground state changes from a W state to a disentangled state as the magnetic field varies. When the Lagrange multiplier λ>3, namely under a strong magnetic current, the ground state holds onto a W state for a large range of the magnetic field strength. A phase transition to the magnetization-current phase occurs under a certain condition.

关键词： Heisenberg-XY chain magnetic-current phase transition.

Daily optimized model for long-term operation of the Three Gorges-Gezhouba Cascade Power Stations

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Science China(Technological Sciences) 2007年第z1期50卷 98-110页

作者： CAO GuangJing1, CAI ZhiGuo1?, LIU ZhiWu1 & WANG GuangQian2.1 China Three Gorges Project Corporation, Yichang 443002. China 2.state key {2. of Hydroscience and {2., tsinghua university, beijing 100084, China China Three Gorges Project Corporation Yichang 443002 China state key {2. of Hydroscience and {2. Tsinghua University Beijing 100084 China

This paper presents the step-by-step genetic algorithm based on artificial intelligence guidance and builds a long-term daily optimized operating model for the Three Gorges-Gezhouba Hydropower Complex with single generating set as the based operating unit. Actual operating data from 2.04 to 2.06 are used to verify the model, and results show that the simulation accuracy determined by measuring the total amount of cascade power generation reaches 99.66%. Statistic hydrological data of normal years and actual data of three years of 2.04―2.06 are respectively used to perform an optimized prediction of the power generation process and benefits in future when the water stored in the TGP Reservoir reaches 175 m level and power generation benefits under different operation modes, such as delayed subsiding water level, advance water storage, and adopting of different flood-limited water levels, are forecasted. In the case of years with normal inflows, the total amount of cascade power generation running on current specifications reaches 107500 GWh per year. If the commencement of water storage after the flood season is moved forward by 2. days, the amount of power generation can be increased by 3400 GWh per year. If the limited water level in the flood season is raised by three to five meters, the amount of power generation can be increased by 1600 to 32.0 GWh per year. If the commencement of water storage is moved forward while the maximum water level allowed in the flood season is raised, the amount of power generation can be increased by 6400 GWh per year.

关键词： cascade operation Three Gorges Project genetic algorithm optimization forecast

Delayed response model for bankfull discharge predictions in the Yellow River

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International Journal of Sediment Research 2011年第4期26卷 445-459页

作者： Baosheng WU and Lingyun LI 1 Prof.,state key {2. of Hydroscience and {2.,tsinghua university,beijing 100084,China, 2.Ph.D.and Research hydraulic Engineer,Changjing River Scientific Research Institute,Wuhan 430010,China [a] Prof. State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing 100084 China [b] Ph.D. and Research hydraulic Engineer Changjing River Scientific Research Institute Wuhan 430010 China

Delayed response means that channels cannot achieve a new equilibrium state immediately following disruption;the channel requires a response time or relaxation time to reach *** follows that the morphological state of fluvial system represents the cumulative effects of all previous disturbances and environmental conditions.A unique feature of the delayed response model for bankfull discharge is that the model is capable of representing the cumulative effects of all previous flow conditions when applied to predict the path/trajectories of bankfull discharge in response to altered flow *** this paper,the delayed response model was modified by readjusting the weight for the initial boundary conditions and introducing a variableβwith respect to *** modified model was then applied to the bankfull discharge calculations for three selected river reaches of the Yellow River,with each reach having different geomorphic settings and constraints. Results indicated that the modified model can predict accurately the bankfull discharge variation in response to changes in flow discharge and sediment load conditions that have been dramatically altered in the *** also demonstrated the strong dependence of current bankfull discharge on the previous years’ flow conditions,with the relaxation time varied from 2.to 14 years,meaning that the bankfull discharge was not only affected by the flow discharge and sediment load in the current year,but also by those in previous 1 to 13 ***,the relaxation time of bankfull discharge adjustment was inversely proportional to the long-term average suspended sediment concentrations,and this may be explained by fact that high sediment concentrations may have a high potential to perform geomorphic work and there is more sediment readily available to shape the channel boundary and geometry.

关键词： Yellow River Bankfull discharge Delayed response Flow discharge Sediment load Relaxation time

A measurement error model for microarray data analysis

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Progress in Natural Science:Materials International 2005年第7期15卷 614-620页

作者： ZHOU Yiming and CHENG Jing ( Department of Biological Sciences and Biotechnology, tsinghua university, beijing 100084, China {2. key laboratory of Biomembrane and Membrane Biotechnology, tsinghua university, beijing 100084, China National engineering Research Center for beijing Biochip Technology, 18 Life Science Parkway, beijing 102.06, China) Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China. state key {2. of Biomembrane and Membrane Biotechnology Tsinghua University Beijing 100084 China. National engineering Research Center for beijing Biochip Technology 18 Life Science Parkway Beijing 102206 China

Microarray technology has been widely used to analyze the gene expression levels by detecting fluorescence intensity in a high throughput fashion. However, since the measurement error produced from various sources in microarray experiments is heterogeneous and too large to be ignored, we propose here a measurement error model for microarray data processing, by which the standard deviation of the measurement error is demonstrated to be linearly increased with fluorescence intensity. A robust algorithm, which estimates the parameters of the measurement error model from a single microarray without replicated spots, is provided. The model and algorithm for estimating of the parameters from a given data set are tested on both the real data set and the simulated data set, and the result has been proven satisfactory. And, combining the measurement error model with traditional Z-test method, a full statistical model has been developed It can significantly improve the statistical inference for identifying differentially expressed genes.

关键词： microarray measurement error model parameter estimation differentially expressed genes.

Research on Theoretical Model of Linear Frequency Modulation Interferometry

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Chinese Journal of Lasers 2000年第3期9卷 28-34页

作者： CHEN Yan ZHAO Yang (state key {2. of Precision Measurement Technology and Instruments, Department of Precision Instruments,{2., beijing 100084,China) 清华大学精密测试技术及仪器国家重点实验室北京 100084

In this paper, the principle of linear frequency-modulation (LFM) with an external microcavity laser is analyzed mathematically and a method to establish the math model of LFM heterodyne interference is presented. The expression of LFM heterodyne interference is deduced by an illustration of a triangular frequency modulation. At present, one application of the LFM technique is non-guide absolute distance measurement. Experimental results of a system for absolute distance measurement based on a microchip solid laser and LFM technique are given. Based on the precisely theoretical model some effective approaches to improve the performance of LFM and decrease the measuring error are discussed.

关键词： linear frequency modulation heterodyne interference absolute distance measurement

ADAPTIVE VARIABLE STRUCTURE CONTROLLERS AND APPLICATION TO ENGINE IDLE SPEED CONTROL SIMULATION

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Chinese Journal of Mechanical engineering 2003年第2期16卷 171-174页

作者： Hui Qing Quyang Minggaostate key {2. of AutomotiveSafety and Energy,{2.,beijing 100084, China state key {2. of Automotive Safety and Energy Tsinghua University Beijing 100084 China

A neural-network-based adaptive variable structure control methodology isproposed for the tracking problem of nonlinear discrete-time input-output systems. The unknowndynamics of the system are approximated via radial basis function neural networks. The control lawis based on sliding modes and simple to implement. The discrete-time adaptive law for tuning theweight of neural networks is presented using the adaptive filtering algorithm with residueupper-bound compensation. The application of the proposed controller to engine idle speed controldesign is discussed. The results indicate the validation and effectiveness of this approach.

关键词： variable structure control adaptive control neural networks nonlineardiscrete-time systems idle speed control

Orthogonally linear polarized lasers (I)——principle and devices

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Progress in Natural Science:Materials International 2005年第7期15卷 586-595页

作者： ZHANG Shulian and XU Ting (state key {2. of Precision Measurement Technology and Instruments, Department of Precision Instruments, {2., beijing 100084, China) state key {2. of Precision Measurement Technology and Instruments Department of Precision Instruments Tsinghua University Beijing 100084 China

Two kinds of orthogonally polarized lasers, i. e. Zeeman dual-frequency lasers and four-frequency ring lasers (laser gyros) have been developed since the invention of lasers, in which circularly polarized lights oscillate. This paper summarizes recent progress of the study on orthogonally linear polarized lasers with the standing wave cavity. Firstly, the expression of producing orthogonally linear polarized lights in standing wave cavity, i. e. laser frequency splitting, is given. Almost all the birefringence effects made in laser cavity are used to produce orthogonally linear polarized lights. The effect includes quartz crystal birefringence effect, calcite birefringence effect, stress (photo-elastic) birefringence effect and electro-optical birefringence effect. Secondly, several physical phenomena of orthogonally linear polarized lasers are discovered such as aberrance of frequency splitting curves caused by optical activity of quartz crystal, order-passing of longitudinal modes with frequency splitting and strong modes competition. Finally, because the traditional Zeeman dual frequency laser cannot output frequency difference larger than 3 MHz, the approaches of obtaining larger frequency difference are studied. The sequential results, several kinds of orthogonally polarized lasers, are described, such as birefringence dual frequency lasers outputting a frequency difference from 40 MHz to hundreds of megahertz, birefringence-Zeeman dual frequency lasers outputting a frequency difference from 1 MHz to hundreds of megahertz, the LD pumped YAG birefringence dual frequency laser outputting frequency difference of several gigahertz, and the lasers whose longitudinal mode spacing is c/4L instead of c/2. .

关键词： orthogonally polarized laser dual frequency laser intra-cavity birefringence Zeeman effect photo-elastic birefringence electro-optical birefringence frequency splitting.

Sediment delivery ratio and its uncertainties on flood event scale:Quantification for the Lower Yellow River

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Science China(Technological Sciences) 2010年第3期53卷 854-862页

作者： FU XuDong 1,JIANG LiWei 1,WU BaoSheng 1,HU ChunHong 2.WANG GuangQian 1 &FEI XiangJun 1 1state key {2. of Hydroscience and {2.,tsinghua university,beijing 100084,China 2.hina Institute of Hydropower and Water Resources Research,beijing 100044,China 1. state key {2. of Hydroscience and {2. Tsinghua University Beijing 100084 China2. China Institute of Hydropower and Water Resources Research Beijing 100044 China

Sediment delivery ratio(SDR)for fluvial rivers was formulated with sediment rating *** observed data of SDR on flood event scale of the Lower Yellow River(LYR)were adopted to examine the formulation and to calibrate the model parameters.A regression formula of SDR was then established and its 95%prediction interval was accordingly quantified to represent its overall *** types of factors including diversity of the incoming flow conditions,river self-regulation processes,and human activities were ascribed to the *** following were shown:(1)With the incoming sediment coefficient(ISC)being a variable,it was not necessary to adopt the incoming flow discharge as the second variable in the formulation of SDR;and(2.ISC=0.003 and therefore SDR=2.might be a threshold for distinguishing the characteristics of sediment transport within the *** findings would highlight sediment transport characteristics on the scale of flood event and contribute to uncertainty based analysis of water volume required for sediment transport and channel maintenance of the LYR.

关键词： sediment delivery ratio Lower Yellow River flood event uncertainty prediction interval

Anomalous magnetotransport in LaMn_(1-x)Te_xO_3

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Science China(Physics,Mechanics & Astronomy) 2009年第7期52卷 987-992页

作者： TAN GuoTai1,2. CHEN ZhengHao3 & ZHANG XiaoZhong4,5 1 key laboratory of Beam Technology & Materials Modification of the Ministry of Education, Institute of Low Energy Nuclear Physics, {2. Normal {2., {2. 100875, China 2.{2. Radiation Center, {2. 100875, China 3 laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, {2. 100080, China 4 key laboratory of Advanced Materials of the Ministry of Education, Department of Materials Science and engineering, {12., beijing 100084, China 5 {2. National Center for Electron Microscopy, {12., beijing 100084, China 1. key laboratory of Beam Technology & Materials Modification of the Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing 100875 China 2. beijing Radiation Center Beijing 100875 China 3. laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China 4. key laboratory of Advanced Materials of the Ministry of Education Department of Materials Science and Engineering Tsinghua University Beijing 100084 China 5. beijing National Center for Electron Microscopy Tsinghua University Beijing 100084 China

The LaMn1-xTexO3+δ (x=0.1, 0.2. 0.3) were synthesized using solid-state reaction method for the first time. X-ray photoemission spectrum (XPS) shows that in the samples the Te ions have a valence of Te4+, and Mn3+ ions are partly converted into Mn2. and Mn4+ due to the excess oxygen and Te doping. The magnetotransport associated with Mn2., Mn3+ and Mn4+ was investigated. The experimental results show that the samples are insulator at 0 T when the amount of Mn3+ is much larger or less than the sum of Mn2. and Mn4+; by contrast, the samples display metal to insulator transition with increasing temperature when the amount of Mn3+ is close to the sum of Mn2. and Mn4+. These anomalous magnetotransport behaviors were analyzed in the frame of the double-exchange (DE) mechanism.

关键词： colossal magnetoresistance La-Te-Mn-O magnetotransport