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Fractional derivative statistical damage model of unsaturated expansive soil based on unified hydraulic effect

Journal of Mountain Science 2023年第9期20卷 2769-2782页

作者： zhang hua WANG Peng School of Architecture and Civil Engineering Chengdu UniversityChengdu 610106China Sichuan Provincial Engineering Research Center of City Solid Waste Energy and Building Materials Conversion and Utilization Technology Chengdu UniversityChengdu 610106China Geotechnical Engineering Institute Sichuan Institute of Building ResearchChengdu 610081China Sichuan Engineering Research Center for Mechanical Properties and Engineering Technology of Unsaturated Soils Chengdu UniversityChengdu 610106China

Unsaturated expansive soil is widely distributed in China and has complex engineering *** paper proposes the unified hydraulic effect shear strength theory of unsaturated expansive soil based on the effective stress principle,swelling force principle,and soil–water *** the viscoelasticity and structural damage of unsaturated expansive soil during loading,a fractional hardening–damage model of unsaturated expansive soil was *** model parameters were established on the basis of the proposed calculation method of shear strength and the triaxial shear experiment on unsaturated expansive *** proposed model was verified by the experimental data and a traditional damage *** proposed model can satisfactorily describe the entire process of the strain-hardening law of unsaturated expansive ***,by investigating the damage variables of the proposed model,it was found that:(a)when the values of confining pressure and matric suction are close,the coupling of confining pressure and matric suction contributes more to the shear strength;(b)there is a damage threshold for unsaturated expansive soil,and is mainly reflected by strength criterion of infinitesimal body;(c)the strain hardening law of unsaturated expansive soil is mainly reflected by fractional derivative operator.

关键词： Unsaturated expansive soil Unified hydraulic effect Shear strength theory Hardening-damage model Fractional derivative

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Filtering of long-term dependent fractal noise in fiber optic gyroscope

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Journal of Systems Engineering and Electronics 2010年第6期21卷 1041-1045页

作者： Chunhong hua zhang Ren Minhu zhang School of Automation Science and Electrical Engineering Beihang University Beijing 100191 E R. China

Stochastic noises of fiber optic gyroscope （FOG） mainly contain white noise and fractal noise whose long-term dependent component causes FOG a rather slow drift. In order to eliminate this component, a two-step filtering methodology is proposed. Firstly, fractional differencing （FD） method is introduced to trans-form fractal noise into fractional white noise based on the estima-tion of Hurst exponent for long-term dependent fractal process, which together with the existing white noise make up of a gener-alized white noise. Further, an improved denoising algorithm of wavelet maxima is developed to suppress the generalized white noise. Experimental results show that the basic noise terms of FOG greatly decrease, and especially the slow drift is restrained effectively. The proposed methodology provides a promising ap-proach for filtering long-term dependent fractal noise.

关键词： fiber optic gyroscope (FOG) fractal noise long-term dependence fractional differencing wavelet denoising.

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Doping-induced phase transition enables better electrocatalysts

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Science China Materials 2018年第12期61卷 1623-1624页

作者： Xiao zhang Zhuangchai Lai hua zhang School of Materials Science and Engineering Nanyang Technological University

Switching from fossil-fuel economy to hydrogen economy requires efficient catalysts to facilitate several funda- mental electrochemical reactions,including oxygen evolution reaction (OER),hydrogen evolution reaction (HER),oxygen reduction reaction (ORR),and hydrogen oxidation reaction (HOR).At present,platinum-group materials are still considered as the state-of-the-art catalysts,which,however,are rare and expensive,resulting in tremendous restrictions to wide *** future of hydrogen economy demands the design of cost-effective and highly active catalysts that are geologically abundant, particularly for affordable and scalable device *** for non-platinum-group electrocatalysts,strategies to enhance their catalytic performances include controlling their size,morphology and composition,creating defects and strains,as well as modulating the van der Waals interactions and crystal phases,etc.[1,2].Although remarkable progress has been achieved,innovations in catalyst design that aim to further promote catalytic activities are still highly desired.

关键词： Doping-induced phase transition enables better electrocatalysts

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Entanglement Criterion of N-Qubit State

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Communications in Theoretical Physics 2006年第4期45卷 601-604页

作者： zhang hua WU Xiao-hua Department of Physics Sichuan University Chengdu 610064 China

In this paper, we shall develop a generic scheme to construct the criterion that an N-qubit state has true N-particle entanglement. For the N = 3 case, we show that violation of the Mermin＇s inequality │ E^LHV （σ^ x× σ^ y× σ^y ＋ σ^y × σ^x×σ^y ＋ σ^y ×σ^y× σ^x＆ -σ^x × σ^x ×σ^x）│≤2, is sufficient to confirm three-particle entanglement.

关键词： N-particle entanglement Mermin's inequality

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Inferring the Physics of Structural Evolution of Multicomponent Polymers via Machine-Learning-Accelerated Method

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Chinese Journal of Polymer Science 2023年第9期41卷 1377-1385,I0006页

作者： Kai-hua zhang Ying Jiang Liang-Shun zhang School of Chemistry Center of Soft Matter Physics and Its ApplicationsBeihang UniversityBeijing100191China Shanghai Key Laboratory of Advanced Polymeric Materials School of Materials Science and EngineeringEast China University of Science and TechnologyShanghai200237China

Dynamic self-consistent field theory(DSCFT)is a fruitful approach for modeling the structural evolution and collective kinetics for a wide variety of multicomponent ***,solving a set of DSCFT equations remains daunting because of high computational ***,a machine learning method,integrating low-dimensional representations of microstructures and long short-term memory neural networks,is used to accelerate the predictions of structural evolution of multicomponent *** is definitively demonstrated that the neural-network-trained surrogate model has the capability to accurately forecast the structural evolution of homopolymer blends as well as diblock copolymers,without the requirement of“on-the-fly”solution of DSCFT ***,the data-driven method can also infer the latent growth laws of phase-separated microstructures of multicomponent polymers through simply using a few of time sequences from their past,without the prior knowledge of the governing *** study exemplifies how the machine-learning-accelerated method can be applied to understand and discover the physics of structural evolution in the complex polymer systems.

关键词： Machine learning Dynamic self-consistent field theory Structural evolution Block copolymers Homopolymer blends

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Symplectic algebraic dynamics algorithm

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Science China(Physics,Mechanics & Astronomy) 2007年第2期50卷 133-143页

作者： WANG ShunJin zhang hua Center of Theoretical Physics Sichuan UniversityChengdu 610064China

Based on the algebraic dynamics solution of ordinary differential equations and integration of $\hat L$ , the symplectic algebraic dynamics algorithm s? n is designed, which preserves the local symplectic geometric structure of a Hamiltonian system and possesses the same precision of the na?ve algebraic dynamics algorithm ? n . Computer experiments for the 4th order algorithms are made for five test models and the numerical results are compared with the conventional symplectic geometric algorithm, indicating that s? n has higher precision, the algorithm-induced phase shift of the conventional symplectic geometric algorithm can be reduced, and the dynamical fidelity can be improved by one order of magnitude.

关键词： symplectic algebraic dynamics algorithm preserving local symplectic geometric structure reduction of algo-rithm-induced phase shift improving dynamical fidelity

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An improved phase measurement method of integrated pulse profile for pulsar

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Science China(Technological Sciences) 2011年第9期54卷 2263-2270页

作者： zhang hua XU LuPing School of Electronic Engineering Xidian University Xi' an 710071 China

Integrated profile is one of the basic characteristic of X-ray pulsar. Gaussian function fit is used to model the components of X-ray pulsar profile, and it is combined with Poisson distribution model of X-ray pulsar to analyze Cramer-Rao low bound （CRLB） of phase, phase rate estimation and relation between CRLB and profile components. Then, a time domain method using minimum entropy is proposed for profile phase and phase rate estimation, and its effectiveness is explained using simulation examples.

关键词： pulsars phase measurement Cramer-Rao minimum entropy

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Algebraic dynamics algorithm:Numerical comparison with Runge-Kutta algorithm and symplectic geometric algorithm

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Science China(Physics,Mechanics & Astronomy) 2007年第1期50卷 53-69页

作者： WANG ShunJin zhang hua Center of Theoretical Physics Sichuan UniversityChengdu 610064China

Based on the exact analytical solution of ordinary differential equations, a truncation of the Taylor series of the exact solution to the Nth order leads to the Nth order algebraic dynamics algorithm. A detailed numerical comparison is presented with Runge-Kutta algorithm and symplectic geometric algorithm for 12 test models. The results show that the algebraic dynamics algorithm can better preserve both geometrical and dynamical fidelity of a dynamical system at a controllable precision, and it can solve the problem of algorithm-induced dissipation for the Runge-Kutta algorithm and the problem of algorithm-induced phase shift for the symplectic geometric algorithm.

关键词： algebraic dynamics algorithm for ordinary differential equations preserving both geometrical and dynamical fidelity numerical comparison with Runge-Kutta algorithm and symplectic geometric algorithm

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Quasi-sure Flows Associated with Vector Fields of Low Regularity

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Chinese Annals of Mathematics,Series B 2014年第1期35卷 51-68页

作者： Siyan XU hua zhang Faculty of Sciences Ningbo University School of Statistics Jiangxi University of Finance and Economics

The authors construct a solution U_t(x) associated with a vector field on the Wiener space for all initial values except in a 1-slim set and obtain the 1-quasi-sure flow property where the vector field is a sum of a skew-adjoint operator not necessarily bounded and a nonlinear part with low regularity,namely one-fold ***,the equivalence of capacities under the transformations of the Wiener space induced by the solutions is obtained.

关键词： Quasi-sure flows Abstract Wiener space Low regularity

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Evaluation of pelvic lymph node coverage of conventional radiotherapy fields based on bony landmarks in Chinese cervical cancer patients using CT simulation

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2009年第9期10卷 683-688页

作者： Xiang zhang hua YU Department of Gynecologic Oncology Zhejiang Cancer Hospital Hangzhou 310022 China

Objective： To evaluate the pelvic lymph node coverage of conventional pelvic fields based on bony landmarks in Chinese patients with cervical cancer by using computed tomography （CT） simulation images to contour pelvic vessels as substitutes for lymph nodes location. Methods： A retrospective review of CT simulation images and conventional pelvic radiation planning data sets was performed in 100 patients with cervical cancer at the International Federation of Gynecology and Obstetrics （FIGO） Stage liB to IIIB in our hospital. Pelvic arteries were contoured on CT simulation images, and the outlines of conventional pelvic fields were drawn as defined by the gynecologic oncology group （GOG） after hiding the contours. The distances between the following vessel contours and field borders were measured： D1, the superior border of the anterior/posterior （AP） field and the bifurcation of abdominal aorta; D2, the ipsilateral border of the AP field and the distal end of external iliac artery; and D3, the anterior border of the lateral （LAT） field and the distal end of the external iliac artery. The distances were recorded as positive values if the measuring point was within the conventional pelvic fields, or they were recorded as negative values. Lymph nodes coverage was considered adequate when D1≥0 mm, D2〉17 mm or D3≥7 mm. Results： All patients had at least 1 inadequate margin, 97 patients （97.0%） had 2, and 22 patients （22.0%） had all the 3. On the AP field, 95 patients （95%） had the measuring point, the bifurcation of the abdominal aorta, out of the field （D1〈0 mm）, and all the patients had a distance less than 17.0 mm between the distal end of the external iliac artery and ipsilateral border （D2〈1 7.0 mm）. On the LAT field, 24 patients （24%） had a distance less than 7.0 mm between the distal end of the external iliac artery and anterior border （D3〈7.0 mm）. Conclusion： We observed that conventional pelvic fields based on bony landmarks provided inadequate coverage of pelvi

关键词： Cervical cancer Radiotherapy planning Computed tomography (CT) simulation Lymph nodes

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