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Variational approach for the flow of Ree–Eyring and Casson fluids in pipes

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International Journal of Modeling, Simulation, and Scientific Computing 2016年第2期7卷 126-138页

作者： Taha Sochi university college london department of physics&Astronomy Gower Street LondonWC1E 6BTUK

The flow of Ree–Eyring and Casson non-Newtonian fluids is investigated using a variational principle to optimize the total *** variationally obtained solutions are compared to the analytical solutions derived from the Weissenberg–Rabinowitsch–Mooney equation and the results are found to be identical within acceptable numerical errors and modeling approximations.

关键词： Fluid mechanics tube flow Ree-Eyring Casson Weissenberg-Rabinowitsch-Mooney variational method total stress optimization.

Emissivity: A Program for Atomic Transition Calculations

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Communications in Computational physics 2010年第5期7卷 1118-1130页

作者： Taha Sochi university college london Department of Physics&AstronomyGower StreetLondonWC1E 6BTUK

In this article we report the release of a new program for calculating emissivity and other physical parameters in atomic transition *** program,which can be downloaded with its documentation and a sample of input and output files from ***/***,passed various rigorous tests and was used alongside R-matrix and Autostructure codes to generate theoretical data and analyze observational *** is particularly useful for investigating atomic transition lines in astronomical context as the program is capable of generating a huge amount of theoretical data and comparing it to observational line list.A number of atomic transition algorithms and analytical techniques are implemented within the program and can be very useful in various *** program can be described as fast and ***,it requires modest computational resources.

关键词： Atomic transition recombination autoionization emissivity computer code thermodynamic equilibrium decay routes Saha population

Effect of secondary radiation force on aggregation between encapsulated microbubbles

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Chinese physics B 2011年第11期20卷 359-364页

作者：张艳丽郑海荣汤孟兴章东 Key Laboratory of Modern Acoustics of Ministry of Education Institute of AcousticsNanjing University Institute of Biomedical and Health Engineering Shenzhen Institutes of Advanced TechnologyChinese Academy of Sciences department of bioengineering Imperial College London

Secondary radiation force can be an attractive force causing aggregates of encapsulated microbubbles in ultrasonic molecular imaging. The influence of the secondary radiation force on aggregation between two coated bubbles is investigated in this study. Numerical calculations are performed based on four simultaneous differential equations of radial and translational motions. Results show that the secondary force can change from attraction to repulsion during approach, and stable microbubble pairs can be formed in the vicinity of resonant regions; the possibility of microbubble aggregations can be reduced by using low exciting amplitude, ultrasonic frequencies deviating from the resonant frequencies or microbubbles with small compressibility.

关键词： microbubbles secondary radiation force aggregation

A New Mixed Clustering-Based Method to Analyze the Gait of Children with Cerebral Palsy

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Computers, Materials & Continua 2021年第2期66卷 1551-1562页

作者： Jing Hu Ling Zhang Jie Li Qirun Wang department of Rehabilitation Medicine Children’s Hospital of Nanjing Medical UniversityNanjing210008China Liaoning Children’s Hospital Shenyang110085China Shenyang Jing’an Mental Health Hospital Shenyang110163China department of physics and Astronomy University College LondonLondon0044UK

Cerebral palsy is a group of persistent central movement and posturaldevelopmental disorders, and restricted activity syndromes. This syndrome iscaused by non-progressive brain damage to the developing fetus or infants. Cerebralpalsy assessment can determine whether the brain is behind or abnormal. If itexists, early intervention and rehabilitation can be carried out as soon as possibleto restore brain function to the greatest extent. The direct external manifestation ofcerebral palsy is abnormal gait. Accurately determining the muscle strengthrelatedreasons that cause this abnormal gait is the primary problem for *** this paper, clustering methods were used to compare and analyze the differencesbetween the abnormal and normal gait parameters of children with andwithout cerebral palsy. Since the collected data contains overlapping data thatmay be mutated, while the centroids are also different, the expected result is *** solve this problem, a mixed clustering method is proposed that combinesthe advantages of K-means and hierarchical clustering, meaning that eachset of data shows a similar trend to specific parameters. Experiment results showthat this method can detect cerebral palsy through the difference between theabnormal gait of children with cerebral palsy and that of normal children.

关键词： Cerebral palys gait analysis children mixed clustering

Microstructure evolution and mechanical properties of Ti2AlNb/TiAl brazed joint using newly-developed Ti–Ni–Nb–Zr filler alloy

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Progress in Natural Science:Materials International 2020年第3期30卷 410-416页

作者： Xinyu Ren Haishui Ren Yonglai Shang Huaping Xiong Kai Zhang Jinghua Zheng Dong Liu Jianguo Lin Jun Jiang Welding and Plastic Forming Division Beijing Institute of Aeronautical Materials HH Wills physics Laboratory School of Physics University of Bristol department of Mechanical Engineering Imperial College London

Joining of TiAlNb alloy to TiAl intermetallics was conducted by the newly-developed Ti–Ni–Nb–Zr brazing filler *** microstructure evolution of the joints was investigated by scanning electron microscope (SEM),energy dispersive spectrometer (EDS) and electron backscatter diffraction (EBSD).The macro-micro mechanical properties were studied by shear test and nano-indentation *** interfacial microstructures across the brazing seam were TiAlNb substrate,α-TiAl+β-Ti,γ-TiAl+TiNi+TiNi+α-TiAl,α-TiAl+β-Ti,TiAl *** TiNi phase were firstly dissolved in the joints brazed at 1000°C for 10 min and then precipitated after a prolonged holding time of 15 *** nano-indentation test revealed that TiNi phase exhibited the highest hardness of 12.60 *** joints brazed at 1000°C/15 min presented the maximum shear strength of271 *** dissolution and precipitation behavior of TiNi phase was also discussed.

关键词： Brazing TiAl Ti2AlNb EBSD Microstructure evolution Nano-indentation

Reverse Rotation of Ring-Shaped Perturbation on Homogeneous Bose–Einstein Condensates

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Chinese physics Letters 2021年第9期38卷 11-17页

作者： Peng Gao Zeyu Wu Zhan-Ying Yang Wen-Li Yang School of physics Northwest UniversityXi’an 710127China Shaanxi Key Laboratory for Theoretical physics Frontiers Xi’an 710127China department of physics and Astronomy University College LondonLondon WC1E 6BTUK Peng Huanwu Center for Fundamental Theory Xi’an 710127China Institute of modern physics Northwest UniversityXi’an 710127China

We numerically study the dynamics of rotating ring-shaped perturbation on two-dimensional homogeneous Bose–Einstein condensates,where a new ring-shaped structure with reverse rotation *** reversely rotating mode is directly caused by the existence of the plane wave(namely the homogeneous background).By the modified linear stability analysis method,we quantitatively predict the influence of the background’s density on perturbation dynamics,including the velocity,amplitude,and frequency of the two *** construct an approximative solution to describe the short-lived dynamics of initial perturbation,which agrees well with our numerical ***,after the two rings separate,the transfer of atom number between them becomes linear,and the rate of transfer is impacted by the radial momentum of initial perturbation.

关键词： perturbation perturbation Einstein

Reply:Is the evolution of tumors Darwinian or non-Darwinian?

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National Science Review 2018年第1期5卷 17-19页

作者： Marc J Williams Benjamin Werner Chris P Barnes Trevor A Graham Andrea Sottoriva Evolution and Cancer Laboratory Barts CancerInstitute Queen Marry University of London department of Cell and Developmental Biology University College London Centre for Mathematics and physics in the Life Sciences and Experimental Biology (CoMPLEX) University College London Centre for Evolution and Cancer The Institute of Cancer Research department of Genetics Evolution and EnvironmentUniversity College London

Wu and colleagues’letter discusses the limitations of the use of a single sample per tumor to investigate neutral evolution in human *** evolution describes the situation in which there is no differential clonal selection amongst the population of cells within a cancer:all mutations thataccrue during growth are passengers and all drivers were already present in the

关键词： Reply:Is the evolution of tumors Darwinian or non-Darwinian VAF

Nanophotonics shines light on hyperbolic metamaterials

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Light(Science & Applications) 2022年第2期11卷 145-148页

作者： Andreas Aigner Judith M.Dawes Stefan A.Maier Haoran Ren Chair in Hybrid Nanosystems Nanoinstitute MunichFaculty of PhysicsLudwig-Maximilians-University MunichMunich 80539Germany MQ Photonics Research Centre Department of Physics and AstronomyMacquarie UniversityMacquarie ParkNSW 2109Australia.3Department of PhysicsImperial College LondonLondon SW72AZUK 不详

Hyperbolic metamaterials with a unique hyperbolic dispersion relation allow propagating waves with infinitely largewavevectors and a high density of states. Researchers from Korea and Singapore provide a comprehensive review ofhyperbolic metamaterials, including artificially structured hyperbolic media and natural hyperbolic materials. Theyexplain key nanophotonic concepts and describe a range of applications for these versatile materials.

关键词： materials. hyperbolic infinitely

Virial Coefficients from Unified Statistical Thermodynamics of Quantum Gases Trapped under Generic Power Law Potential in d Dimension and Equivalence of Quantum Gases

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Communications in Theoretical physics 2016年第9期65卷 291-296页

作者： Shah Mohammad Bahauddin Mir Mehedi Faruk physics and Astronomy Rice University Houston USA Theoretical physics Blackett Laboratory Imperial College London SW7 2AZ United Kingdom department of Theoretical physics University of Dhaka Dhaka-1000 Banglagesh

From the unified statistical thermodynamics of quantum gases, the virial coefficients of ideal Bose and Fermi gases, trapped under generic power law potential are derived systematically. From the general result of virial coefficients, one can produce the known results in d = 3 and d = 2. But more importantly we found that, the virial coefficients of Bose and Fermi gases become identical(except the second virial coefficient, where the sign is different)when the gases are trapped under harmonic potential in d = 1. This result suggests the equivalence between Bose and Fermi gases established in d = 1(J. Stat. Phys. DOI 10.1007/s10955-015-1344-4). Also, it is found that the virial coefficients of two-dimensional free Bose(Fermi) gas are equal to the virial coefficients of one-dimensional harmonically trapped Bose(Fermi) gas.

关键词： virial coefficients quantum gas equivalence