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The Multi-parameter Test of Gravitational wave Dispersion with Principal Component Analysis

Research in Astronomy and Astrophysics 2024年第5期24卷 140-150页

作者： Zhi-Chu ma Rui Niu wen Zhao CAS Key Laboratory for Research in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaHefei 230026China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China

In this work, we consider a conventional test of gravitational wave(Gw) propagation which is based on the phenomenological parameterized dispersion relation to describe potential departures from General Relativity(GR)along the propagation of Gws. But different from tests conventionally performed previously, we vary multiple deformation coefficients simultaneously and employ the principal component analysis(PCA) method to remedy the strong degeneracy among deformation coefficients and obtain informative posteriors. The dominant PCA components can be better measured and constrained, and thus are expected to be more sensitive to potential departures from the waveform model. Using this method we analyze ten selected events and get the result that the combined posteriors of the dominant PCA parameters are consistent with GR within 99.7% credible intervals. The standard deviation of the first dominant PCA parameter is three times smaller than that of the original dispersion parameter of the leading order. However, the multi-parameter test with PCA is more sensitive to not only potential deviations from GR but also systematic errors of waveform models. The difference in results obtained by using different waveform templates hints that the demands of waveform accuracy are higher to perform the multiparameter test with PCA. whereas, it cannot be strictly proven that the deviation is indeed and only induced by systematic errors. It requires more thorough research in the future to exclude other possible reasons in parameter estimation and data processing.

关键词： gravitational waves-gravitation-black hole physics

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Highly Optimized Code Generation for Stencil Codes with Computation Reuse for GPUs

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Journal of Computer Science & Technology 2016年第6期31卷 1262-1274页

作者： wen-Jing ma Kan Gao Guo-Ping Long Laboratory of Parallel Software and Computing Science Institute of Software Chinese Academy of Sciences Beijing 100190 China State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing 100190 China Information Center China Association for Science and Technology Beijing 100863 China

Computation reuse is known as an effective optimization technique. However, due to the complexity of modern GPU architectures, there is yet not enough understanding regarding the intriguing implications of the interplay of compu- ration reuse and hardware specifics on application performance. In this paper, we propose an automatic code generator for a class of stencil codes with inherent computation reuse on CPUs. For such applications, the proper reuse of intermediate results, combined with careful register and on-chip local memory usage, has profound implications on performance. Current state of the art does not address this problem in depth, partially due to the lack of a good program representation that can expose all potential computation reuse. In this paper, we leverage the computation overlap graph （COG）, a simple representation of data dependence and data reuse with ＂element view＂, to expose potential reuse opportunities. Using COG, we propose a portable code generation and tuning framework for GPUs. Compared with current state-of-the-art code generators, our experimental results show up to 56.7% performance improvement on modern GPUs such as NVIDIA C2050.

关键词： GPGPU OpenCL stencil code generation computation reuse

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Evolution of microstructure and texture of cold-drawn polycrystalline Ag with low stacking fault energy

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Science China(Technological Sciences) 2015年第7期58卷 1146-1153页

作者： ma XiaoGuang CHEN Jian CHEN Zheng YAN wen State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern Polytechnical University School of materials Science and Chemical Engineering Xi'an Technological University

The evolution of microstructure and texture for drawn polycrystalline Ag was investigated by transmission electron microscopy and electron backscattering *** results show that there are deformation twins and some un-tangled discrete dislocations at low *** the strain is increased to 0.58,a lot of high density dislocation walls and microbands come into *** the same time,some twins lose the twinning relationship of 60°.At a strain of 0.94,both dislocation boundaries and twin boundaries will rotate to the axis direction of wires and the shear bands start to *** the strain is higher than 1.96,most of the boundaries are parallel to the drawn *** analysis indicates that with the strain increasing,the volume fraction of complex texture component decreases,butandtexture components ***,the variation in the volume fraction of each texture component as strains is not evident when the strains are higher than *** polycrystalline Ag with low stacking fault energy,complex texture components are easily formed.

关键词： polycrystalline Ag cold-drawn deformation microstructure deformation twinning stacking fault energy

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Improved non-negative tensor Tucker decomposition algorithm for interference hyper-spectral image compression

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Science China(Information Sciences) 2015年第5期58卷 112-120页

作者： wen Jia ZHAO JunSuo ma Caiwen wANG CaiLing Science and Technology on Integrated Information System Laboratory Institute of SoftwareChinese Academy of Sciences Xi'an Institute of Optics and Precision Mechanics Chinese Academy of Sciences College of Computer Science Xi'an Shiyou University

The compression method, first proposed in 2012, is based on the non-negative tensor decomposition for interference hyper-spectral image data. As a tensor is generated by a huge amount of interference hyper-spectral images, the multiplicative update algorithm is made extremely complicated, and even *** reduce the computational cost and speed up the convergence, this paper, based on the characteristics of interference hyper-spectral images, develops a new algorithm using different down-sampling factors for different non-negative wavelet sub-band tensors. The experimental results showed that this algorithm could significantly shorten the running time, while maintaining a good compression performance compared with the conventional methods.

关键词： interference hyper-spectral images LASIS three-dimensional lifting wavelet transform non-negative tensor decomposition image com

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Bifurcation behaviors of catalytic combustion in a micro-channel

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Journal of Thermal Science 2008年第1期17卷 84-89页

作者： wen Zeng maozhao Xie Hongan ma wei Xu School of Aero-engine and Energy Engineering Shenyang Institute of Aeronautical Engineering Shenyang 110034China School of Energy and Power Engineering Dalian University of Technology Dalian 116024 China

Bifurcation analysis of ignition and extinction of catalytic combustion in a short micro-channel is carded out with the laminar flow model incorporated as the flow model. The square of transverse Thiele modulus and the residence time are used as bifurcation parameters. The influences of different parameters on ignition and extinction behavior are investigated. It is shown that all these parameters have great effects on the bifurcation behaviors of ignition and extinction in the short micro-channel. The effects of flow models on bifurcation behaviors of combustion are also analyzed. The results show that in comparison with the flat velocity profile model, for the case of the laminar flow model, the temperatures of ignition and extinction of combustion are higher and the unsteady multiple solution region is larger.

关键词： catalytic combustion bifurcation theory short monolith

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Computation of rolling resistance caused by rubber hysteresis of truck radial tire

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第5期8卷 778-785页

作者： ma Gai-ling XU Hong CUI wen-yong College of Mechanical and Electrical Engineering Beijing University of Chemical Technology Beijing 100029 China

Applying the results of stress and strain calculated by 3D finite element model of truck radial tire 11.00R20, a maTLAB program used to compute rolling resistance of the tire caused by hysteresis rolling resistance (HRR) is worked out. The HRR distribution on different part of tire section, and the effects of speed, load, internal pressure and the width of the rim on HRR are analyzed. The analysis results showed that energy loss produced by tread rubber contributes the most part to HRR of the whole tire, and that to decrease the HRR, the hysteresis factor of the tread rubber should be reduced, and the distribution of the stress and strain on the section be optimized.

关键词： Truck radial tire Hysteresis rolling resistance (HRR) Finite element analysis (FEA) Hysteresis factor Tire structuredesign

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Minimizing chemical interference errors for the determination of lithium in brines by flame atomic absorption spectroscopy analysis

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Rare Metals 2006年第4期25卷 309-315页

作者： wen Xianming ma Peihua ZHU Geqin wU Zhiming Qinghai Institute of Salt Lakes Chinese Academy of Sciences Xining 810008 China Graduate School of Chinese Academy of Sciences Beijing 100039 China

Chemical interferences （ionization and oxide/hydroxide formation） on the atomic absorbance signal of lithium in FAAS analysis of brine samples are elaborated in this article. It is suggested that inadequate or overaddition of deionization buffers can lead to loss of sensitivities under particular operating conditions. In the analysis of brine samples, signal enhancing and oxide/hydroxide formation inducing signal reduction resulting from overaddition of deionization buffers can be seen with varying amounts of chemical buffers. Based on experimental results, the authors have arrived at the optimized operating conditions for the detection of lithium, under which both ionization and stable compound formation can be suppressed. This is a simplified and quick method with adequate accuracy and precision for the determination of lithium in routine brine samples from chemical plants or R＆D laboratories, which contain comparable amounts of lithium with some other components.

关键词： analytical chemistry simplified method FAAS lithium brine deionization oxide/hydroxide formation

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Bayesian inference of the crust–core transition density via the neutron-star radius and neutron-skin thickness data

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Nuclear Science and Techniques 2023年第6期34卷 125-133页

作者： wen-Jie Xie Zi-wei ma Jun-Hua Guo Department of Physics Yuncheng UniversityYuncheng044000China

In this work,we perform a Bayesian inference of the crust-core transition density ρ_(t) of neutron stars based on the neutron-star radius and neutron-skin thickness data using a thermodynamical *** and Gaussian distributions for the ρ_(t) prior were adopted in the Bayesian *** has a larger probability of having values higher than 0.1 fm^(−3) for ρ_(t) as the uniform prior and neutron-star radius data were *** was found to be controlled by the curvature K_(sym) of the nuclear symmetry *** phenomenon did not occur if K_(sym) was not extremely negative,namely,K_(sym)>−200 *** value ofρ_(t) obtained was 0.075_(−0.01)^(+0.005) fm^(−3) at a confidence level of 68%when both the neutron-star radius and neutron-skin thickness data were *** anti-correlations were observed between ρ_(t),slope L,and curvature of the nuclear symmetry *** dependence of the three L-K_(sym) correlations predicted in the literature on crust-core density and pressure was quantitatively *** most probable value of 0.08 fm^(−3) for ρ_(t) was obtained from the L-K_(sym) relationship proposed by Holt et *** larger values were preferred for the other two relationships.

关键词： Crust–core transition density of neutron stars Neutron-star radius Neutron-skin thickness Bayesian inference approach L–K_(sym)

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Non-Semisimple Lie Algebras of Block matrices and Applications to Bi-Integrable Couplings

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Advances in Applied mathematics and Mechanics 2013年第5期5卷 652-670页

作者： Jinghan Meng wen-Xiu ma Department of mathematics and Statistics University of South FloridaTampaFL 33620-5700USA

we propose a class of non-semisimple matrix loop algebras consisting of 3×3 block matrices,and form zero curvature equations from the presented loop algebras to generate bi-integrable *** are made for the AKNS soliton hierarchy and Hamiltonian structures of the resulting integrable couplings are constructed by using the associated variational identities.

关键词： Bi-integrable couplings non-semisimple matrix loop algebras AKNS hierarchy Hamiltonian structure symmetry

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Structural evolution of mesoporous graphene/LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2) composite cathode for Li-ion battery

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Rare Metals 2021年第3期40卷 521-528页

作者： wen-Jie Liu Xian-Zhong Sun Xiong Zhang Chen Li Kai wang wen wen Yan-wei ma Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100190China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201204China

Layered LiMO_(2)(M=Ni,Co,and Mn) is a type of promising cathode materials for high energy density and high work voltage lithium-ion ***,the poor rate performance and low power density hinder its further *** capacity fade is related to the structural transformation in the layered LiMO_(2).In this work,the structural changes of bi-material cathode composed of mesoporous graphene and layered LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)(NCM) were studied via in situ X-ray diffraction(XRD).During different C-rate charge-discharge test at the voltage range of 2.5-4.1 V,the composite cathode of NCM-graphene(NCM-G) reveals better rate performances than pure NCM *** NCM-G composite electrode displays a higher rate capability of 76.7 mah·g^(-1) at 5 C rate,compared to the pure NCM cathode of 69.8 mah·g^(-1)discharge *** in situ XRD results indicate that a reversible phase transition from hexagonal H1 to hexagonal H2 occurs in layered NCM material during 1 C chargedischarge *** the current increasing to 2 C/5 C,the structure of layered NCM material for both electrodes reveals few changes during charge and discharge processes,which indicates the less utilization of NCM component at high ***,the improved rate performance for bi-material electrode is attributed to the highly conductive mesoporous graphene and the synergistic effect of mesoporous graphene and NCM material.

关键词： LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)(NCM) Mesoporous graphene Bi-material In situ X-ray diffraction(XRD) Structural evolution

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