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Restarted Full Orthogonalization Method with Deflation for Shifted Linear Systems

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Numerical Mathematics(Theory,Methods and Applications) 2014年第3期7卷 399-412页

作者： Jun-feng yin Guo-Jian yin Department of Mathematics Tongji University1239 Siping RoadShanghai 200092P.R.China Department of Mathematics The Chinese University of Hong KongShatinNTHong Kong

In this paper,we study shifted restated full orthogonalization method with deflation for simultaneously solving a number of shifted systems of linear *** analysis shows that with the deflation technique,the new residual of shifted restarted FOM is still collinear with each ***,the new approach can solve the shifted systems simultaneously based on the same Krylov *** experiments show that the deflation technique can significantly improve the convergence performance of shifted restarted FOM.

关键词： Shifted linear systems full orthogonalization method restarted Arnoldi process deflation collinear

Uniform Estimate for The Tail Probabilities of Randomly Weighted Sums

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Acta Mathematicae Applicatae Sinica 2014年第4期30卷 1063-1072页

作者： yin-feng WANG Chuan-cun yin Xin-sheng ZHANG Department of Statistics Fudan University School of Business Shanghai Dianji University School of Mathematical Sciences Qufu Normal University

Several authors have studied the uniform estimate for the tail probabilities of randomly weighted *** their maxima. In this paper, we generalize their work to the situation thatis a sequence of upper tail asymptotically independent random variables with common distribution from the is a sequence of nonnegative random variables, independent of and satisfying some regular conditions. Moreover. no additional assumption is required on the dependence structureof {θi,i≥ 1）.

关键词： uniform estimate randomly weighted sums upper tail asymptotically independence class D ∩ζ

Soluble ST2:A Novel Biomarker for Diagnosis and Prognosis of Cardiovascular Disease

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Current Medical Science 2024年第4期44卷 669-679页

作者： yin feng Li-qun HE Department of Cardiology Traditional Chinese and Western Medicine Hospital of WuhanTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430030China

The increasing incidence of cardiovascular disease(CVD)is a significant global health concern,affecting millions of individuals each *** diagnosis of acute CVD poses a formidable challenge,as misdiagnosis can significantly decrease patient survival *** biomarkers have played a vital role in the diagnosis and prognosis of CVDs,but they can be influenced by various factors,such as age,sex,and renal *** ST2(sST2)is a novel biomarker that is closely associated with different *** low reference change value makes it suitable for continuous measurement,unaffected by age,kidney function,and other confounding factors,facilitating risk stratification of ***,the combination of sST2 with other biomarkers can enhance diagnostic accuracy and prognostic *** review aims to provide a comprehensive overview of sST2,focusing on its diagnostic and prognostic value as a myocardial marker for different types of CVDs and discussing the current limitations of sST2.

关键词： soluble ST2 cardiovascular disease combined biomarker diagnosis and prognosis limitations

High-pressure polymorph of TiO_2-Ⅱ from the Xiuyan crater of China

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Chinese Science Bulletin 2013年第36期58卷 4655-4662页

作者： CHEN Ming GU XiangPing XIE XianDe yin feng State Key Laboratory of Isotope Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences School of Geosciences and Info-Physics Central South University Key Laboratory of Mineralogy and Metallogeny Guangzhou Institute of Geochemistry Chinese Academy of Sciences

Abundant TiO2-Ⅱ,a high-pressure polymorph of titanium dioxide,was found in the gneiss fragments of impact-produced breccias from the Xiuyan *** in the gneiss was severely fragmented and fine-grained clasts less than 2 m in size had been transformed to *** thin layered TiO2-Ⅱ is also observed in coarse-grained rutile fragments,where the TiO2-Ⅱ layers distributes along fractures and cracks in *** 30 percent of rutile in the gneiss had been transformed to TiO2-Ⅱ.Fine grains of TiO2-Ⅱ display light bluish grey to light yellow brown in plane-polarized reflected *** investigation shows that TiO2-Ⅱ has an orthorhombic structure with space group *** cell parameters are a=4.543(1),b=5.491(9)and c=4.895(2).Its empirical formula calculated on the basis of two oxygen atoms can be written as(Ti0.985Fe0.008Nb0.006-Si0.003Zr0.001)1.003O2,or simply formula *** to the shock effects of quartz and feldspars,the peak shock pressure and post-shock temperature in the TiO2-Ⅱ-bearing gneiss are estimated to be between 35 and 43 GPa and 300–900°C,*** finding of TiO2-Ⅱ in the shock-metamorphosed gneiss provides another mineral physics evidence for shock origin of the Xiuyan crater.

关键词：陨石坑纳米岫岩高压二氧化钛中国经验公式平面偏振光

Influence of stress anisotropy on the cylindrical cavity expansion in undrained elastic-perfectly plastic soil

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Science China(Technological Sciences) 2018年第3期61卷 370-380页

作者： ZHOU Hang LIU HanLong ZHA YaHui yin feng Key Laboratory of New Technology for Construction of Cities in Mountain Area School of Civil Engineering Chongqing University State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology

This work presents an analysis of the influence of stress anisotropy on cylindrical cavity expansions in an undrained elastic-perfectly plastic soil. This problem was formulated by assuming a large strain in both the elastic and plastic zones around the cavity and a plain strain condition during the cavity expansion process. The solutions for the limit pressure, stress, and excess pore pressure were obtained by introducing the anisotropic initial stress coefficient K_0 into the conventional cylindrical cavity expansion *** proposed solutions were then used to interpret the piezocone penetration test, and the suitability of the solutions was verified by comparing the prediction with the piezocone penetration test data. Subsequently, parametric studies were carried out to investigate the influence of stress anisotropy on the stress, excess pores pressure distributions around an expanding cylindrical cavity, and limit pressure. The results show that the proposed cylindrical cavity expansion method under stress anisotropy is suitable and can be used to investigate the piezocone cone test. The present work improves upon the conventional theoretical framework of cavity expansion and can be applied to the determination of the stresses around axially loaded piles and around in-situ testing devices such as penetrometers.

关键词： anisotropy cylindrical cavity expansion undrained elastic-perfectly plastic

A Class of Preconditioners Based on Positive-Definite Operator Splitting Iteration Methods for Variable-Coefficient Space-Fractional Diffusion Equations

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Communications on Applied Mathematics and Computation 2021年第1期3卷 157-176页

作者： Jun-feng yin Yi-Shu Du School of Mathematical Sciences Tongji UniversityShanghai 200092China

After discretization by the finite volume method,the numerical solution of fractional diffusion equations leads to a linear system with the Toeplitz-like *** theoretical analysis gives sufficient conditions to guarantee the positive-definite property of the discretized ***,we develop a class of positive-definite operator splitting iteration methods for the numerical solution of fractional diffusion equations,which is unconditionally convergent for any positive ***,the iteration methods introduce a new preconditioner for Krylov subspace *** experiments verify the convergence of the positive-definite operator splitting iteration methods and show the efficiency of the proposed preconditioner,compared with the existing approaches.

关键词： Fractional diffusion equations Finite volume method Operator splitting Positive-definite

Oxygen Isotopic Compositions in a Plagioclase-Olivine Inclusion from Ningqiang Similar to Those in Al-rich Chondrules

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Acta Geologica Sinica(English Edition) 2021年第5期95卷 1583-1590页

作者： DAI Deqiu BAO Haimei LIU Shuang yin feng Department of Geology Hunan University of Science and TechnologyXiangtanHunan 411201China Institute of Geochemistry Chinese Academy of SciencesGuiyang 550081China Hunan Provincial Key Laboratory of Shale Gas Resource Utilization Hunan University of Science and TechnologyXiangtanHunan 411201China

We report the petrology and oxygen isotopic composition,using a Cameca Nano SIMS 50L ion microprobe,of a plagioclase-olivine inclusion,C#1,found in the Ningqiang carbonaceous *** addition to major phases(plagioclase,spinel and olivine),C#1 is also surrounded by a pyroxene rim(64 vol%Ca-rich and 36 vol%Ca-poor pyroxenes).On a three-isotope oxygen diagram,δ^(17)O vs.δ^(18)O,the compositions of individual minerals analyzed in C#1 fall along the carbonaceous chondrite anhydrous mineral line(CCAM),and oxygen isotopic compositions in C#1 show significant variability in δ^(18)O and δ^(17)*** oxygen isotopic compositions of the pyroxene rim minerals are similar to those of the other host minerals,which suggests that the rim likely formed from the same melting process as the *** rim is considered to have formed as a result of interaction between an ^(16)O-poor gas and a *** spinel grains are typically ^(16)O-rich and likely of relict origin,which is similar to ^(16)O-rich Ca-,Al-rich inclusions,which are probably a precursor of C#*** inclusion then likely melted in an ^(16)O-poor region where chondrules form,accompanied by oxygen isotope exchange with an ^(16)O-poor *** anorthite,pyroxene and spinel might have undergone fluid-assisted thermal metamorphism on the Ningqiang chondrite parent *** oxygen isotope data and evolution of the C#1 plagioclase-olivine inclusion are similar with those of Al-chondrules in chondrites.

关键词： meteorite petrology oxygen isotopes CAIs plagioclase–olivine inclusion Al-rich chondrules Ningqiang chondrite Shanxi

Wave equation tomographyin baseband with phase correction from the first arrival traveltimes

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石油物探 2017年第1期56卷 69-74页

作者： yin feng Jerry HARRIS Department of Geophysics Stanford University

We use the first arrival traveltime to correct the phase distortion in a nonlinear wave equation inversion *** improves the precision of tomographic reconstruction of a velocity structure with large variations and helps solve the ill-posed problem of wave equation *** the variation of the velocity distribution is large,general non-linear wave equation inversions are very ill-posed and for such strong nonlinear we can not obtain a correct *** of main reasons is that the calculated and observed phase of the wavefield differs greatly if the initial model is far from the true *** leads to highly mismatched phase between the calculated and the observed wave *** is so-called"Cycle Skipping"problem in the full waveform *** phase mismatch is even more pronounced if a high operating frequency is employed in order to increase *** address this problem,we use the first arrival to"demodulate"the wave field in the frequency domain with a goal of restoring the phase of wave *** we minimize an objective function consisting of so called"demodulated"wave field to solve wave equation inversion *** this way,we find that the inversion is much improved,and when the velocity perturbation in a complicated model reaches 35%,we can still obtain a good inversion.A computer simulation shows that our method is very robust for acoustical wave inversion with good reconstruction precision.

关键词：全波形反演随机边界异构并行作业池速度反演

Fast frequency-domain equalization for single-carrier V-BLAST systems over multipath channel

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Science in China(Series F) 2009年第1期52卷 115-125页

作者： feng Ang yin QinYe FAN JianCun School of Electronics and Information Engineering Xi'an Jiaotong University Xi'an 710049 China

A low complex minimum mean-square error frequency-domain decision feedback （MMSE-FDDF） equalization algorithm is proposed in this paper for the single-carrier V-BLAST systems. Exploiting the factor that the discrete Fourier transform （DFT） is unitary, the proposed receiver can equalize the signals by the MMSE detecting to the spectrums in the frequency domain instead of the waveforms in the time domain. In order to obtain the right decisions, the detector must be able to equalize the overall spectrum with regard to each layer. This work can be performed very efficiently since the system matrix has been designed as a special block-circulant-block matrix. Similar to other V-BLAST-like systems, the detecting order has strong impact on the performance of MMSE-FDDF. Therefore, we further give a fast optimally sorting scheme for the MMSE-FDDF architecture. By using the newly constructed matrix, the coefficients computation and the sorting can be combined into one process, and then we employ the modified Gram-Schmidt （MGS） to simplify the process. The simulation results and the computational complexity analysis show that the proposed MMSE-FDDF has better tradeoff between the performance and the complexity than the existing algorithms. In addition, MMSE-FDDF can avoid the performance floor caused by the overlap-and-save technique in the severe dispersive channel.

关键词： single-carrier orthogonal frequency division multiplexing frequency domain equalization V-BLAST ordering Cholesky decomposition