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Calculation of three-dimensional acoustic scattering from Gaussian rough under-ice surface using the Kirchhoff approximation method with modified reflection coefficient

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Chinese Journal of Acoustics 2020年第3期39卷 273-286页

作者： CHEN Wenjian LANG Pengyuan HU Siwei YIN Jingwei SUN Hui ZHANG Yuxiang Acoustic Science and Technology Laboratory Harbin Engineering UniversityHarbin 150001 Key Laboratory of Marine Information Acquisition and Security(Harbin Engineering University) Ministry of Industry and Information TechnologyHarbin 150001 College of Underwater Acoustic Engineering Harbin Engineering UniversityHarbin 150001

The Kirchhoff approximation with a modified reflection coefficient is used to calculate the three-dimensional acoustic scattering of a Gaussian rough under-ice surface.The concept of a local statistical average reflection coefficient of an under-ice surface is proposed in the calculation model.The scattered sound field of a two-dimensional Gaussian rough under-ice surface is divided into coherent scattering and incoherent scattering.A formula is derived for the scattering coefficient of each scattering component,and the three-dimensional scattering intensity is obtained.The relationships between the scattering intensity and(ⅰ)the root-meansquare height of the Gaussian rough under-ice surface,(ⅱ)the angle of incidence,and(ⅲ)the sound frequency are analyzed.The scattering intensity of a Gaussian rough under-ice surface is measured in a laboratory water tank,and the calculation results of the theoretical model are verified.The experimental results are compared with those of the theoretical model using(ⅰ)the present local statistical average reflection coefficient of an under-ice surface and(ⅱ)the mirror reflection coefficient of an under-ice surface from the literature.The calculation results of the model using the local statistical average reflection coefficient agree well with the experimental results.

关键词： surface. coefficient Gaussian

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新建建筑围护结构的传热系数变化研究

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太阳能学报 2010年第6期31卷 717-722页

作者：孔凡红廖胜明郑茂余中南大学能源科学与工程学院长沙410012 哈尔滨工业大学市政环境工程学院哈尔滨150090

对严寒地区新建建筑围护结构的干燥过程进行了模拟,建立了不同干燥时期的热质耦合传递质能平衡方程,确立了围护结构各层多孔介质材料导热系数随含湿量和结冰量的变化关系,对围护结构传热系数的变化情况进行了模拟,分析了新建建筑传热系... 详细信息

对严寒地区新建建筑围护结构的干燥过程进行了模拟,建立了不同干燥时期的热质耦合传递质能平衡方程,确立了围护结构各层多孔介质材料导热系数随含湿量和结冰量的变化关系,对围护结构传热系数的变化情况进行了模拟,分析了新建建筑传热系数随着围护结构不断干燥的逐年变化规律。模拟结果表明:在严寒地区,新建建筑围护结构冬季的传热系数由于内部含湿量结冰要高于夏季围护结构传热系数,但围护结构冬季传热系数逐年下降,尤其前三年下降较明显。

关键词：建筑围护结构围护结构传热系数 BUILDING NEW HEAT TRANSFER coefficient 新建建筑严寒地区模拟结果含湿量干燥过程多孔介质材料年变化规律热质耦合平衡方程结冰冬季导热系数变化情况变化关系夏季

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Factorization for n-D Polynomial Matrices over Arbitrary coefficient Field

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Journal of Systems Science & Complexity 2020年第1期33卷 215-229页

作者： LIU Jinwang LI Dongmei ZHENG Licui School of Mathematics and Computing Sciences Hunan University of Science and TechnologyXiangtan 411201China

Multivariate(n-D)polynomial matrix factorization is one of important research contents in multidimensional(n-D)systems,circuits,and signal processing.In this paper,several results on n-D polynomial matrices factorization over arbitrary coefficient fields are proved.Based on these results,generalizations of some results on general matrix factorization are obtained for given n-D polynomial matrices whose maximal order minors or lower order minors satisfy certain conditions.The proposed results fit for arbitrary coefficient field and have a wide range of application.

关键词： coefficient field matrix factorization multidimensional polynomial matrix order minor

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Parameter Estimation of Linear Frequency Modulated Signals Based on Holder coefficient

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Journal of Harbin Institute of Technology(New Series) 2013年第2期20卷 95-98页

作者： Yu-Ning Zhao Xiao-Dong Yang Yun Lin College of Information and Communication Harbin Engineering University

The current parameter estimation algorithms of chirp rate have high complexity and long calculation time,meantime they are difficult to achieve high estimation rate. Therefore,in order to overcome these problems,in this paper,a new parameter estimation algorithm based on Holder coefficient is presented. Firstly,this algorithm calculates the correlation curve of the Holder coefficient value under different chirp rate. Secondly,this algorithm calculates the correlation curve under different SNR. Finally,the fitting curve expression can be got by the correlation curve,and then the estimation value of chirp rate can also be got. The theory analysis and simulation results show that this algorithm is simple and easy to realize,and has much better application value for real-time estimation.

关键词： parameter estimation LFM signal chirp rate holder coefficient correlation curve

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Delineation of epicardial stenosis in patients with microvascular disease using pressure drop coefficient:A pilot outcome study

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世界心脏病学杂志：英文版（电子版） 2017年第12期9卷 813-821页

作者： Ullhas Udaya Hebbar Mohamed A Effat Srikara V Peelukhana Imran Arif Rupak K Banerjee Department of Mechanical and Materials Engineering University of CincinnatiCincinnatiOH 45221United States Division of Cardiovascular Diseases University of Cincinnati Medical CenterVeteran Affairs Medical CenterCincinnatiOH 45221United States Department of Mechanical and Materials Engineering University of CincinnatiVeteran Affairs Medical CenterCincinnatiOH 45221United States Department of Mechanical and Materials Engineering Veteran Affairs Medical CenterCincinnatiOH 45221United States

AIM To investigate the patient-outcomes of newly developed pressure drop coefficient(CDP) in diagnosing epicardial stenosis(ES) in the presence of concomitant microvascular disease(MVD).METHODS Patients from our clinical trial were divided into two subgroups with:(1) cut-off of coronary flow reserve(CFR) 27.9 groups for assessing major adverse cardiac events(MACE:Primary outcome).Comparisons were also made between the survival curves for FFR 27.9 groups.Two tailed chi-squared and Fischer's exact tests were performed for comparison of the primary outcomes,and the log-rank test was used to compare the Kaplan-Meier survival curves.P 27.9 group(7.7%,2/26) was lower than FFR 27.9 group(12.5%,2/16) was lower than FFR 27.9 group(n = 26) when compared with FFR 27.9 group(n = 16) showed higher survival times compared to FFR group(n = 11);P = 0.58.CONCLUSION CDP correlated significantly with HMR and resulted in better %MACE as well as survival rates in comparison to FFR.These positive trends demonstrate that CDP could be a potential diagnostic endpoint for delineating MVD with or without ES.

关键词： Fractional flow reserve Pressure drop coefficient Microvascular disease Intermediate coronary stenosis Interventional cardiology

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Low remanence temperature coefficient Sm1-xErx(Co,Fe,Cu,Zr)z magnets operating up to 400℃

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Rare Metals 2020年第1期39卷 70-75页

作者： Tian-Li Zhang Bo Zhang Hui Wang Cheng-Bao Jiang Zhi-Hong Zhang Xiao-Qing Wang Wei Zhang School of Materials Science and Engineering Beihang UniversityBeijing100191China State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization Baotou Research Institute of Rare EarthsBaotou014030China

Er-doped Sm1-xErx(CobalFe0.15Cu0.08Zr0.03)7.8(x=0,0.1,0.2,0.3)magnets with a low remanence temperature coefficient were prepared by powder metallurgy method.The influence of Er content on the remanence and microstructure was investigated.X-ray diffractometer(XRD)analysis showed that the magnets with different Er contents consist of 2:17 R phase and 1:5 H phase.Scanning electron microscopy(SEM)analysis showed that the composition of the matrix is consistent with stoichiometric composition and no obvious precipitated phase appears.With the increase in doped Er amount,the temperature stability of Sm1-xErx(CobalFe0.15Cu0.08Zr0.03)7.8(x=0,0.1,0.2,0.3)is getting better.When x is up to 0.3,the magnets with a low remanence temperature coefficient are obtained and the remanence descends tardily from 0.86 to 0.80 T as the temperature rises from room temperature to 400℃.These results indicate that Er substitution for Sm in SmCobased permanent magnets together with optimal composition and proper heat treatment could achieve a desired magnetic performance combined with high thermal stability.

关键词： Permanent magnets Low remanence temperature coefficient Er doped Magnetic performance characterization

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Prediction of different stages of rectal cancer: Texture analysis based on diffusion-weighted images and apparent diffusion coefficient maps

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World Journal of Gastroenterology 2020年第17期26卷 2082-2096页

作者： Jian-Dong Yin Li-Rong Song He-Cheng Lu Xu Zheng Department of Radiology Shengjing Hospital of China Medical UniversityShenyang 110003Liaoning ProvinceChina College of Medicine and Biological Information Engineering Northeastern UniversityShenyang 110036Liaoning ProvinceChina Department of Clinical Oncology Shengjing Hospital of China Medical UniversityShenyang 110011Liaoning ProvinceChina

BACKGROUND It is evident that an accurate evaluation of T and N stage rectal cancer is essential for treatment planning.It has not been extensively investigated whether texture features derived from diffusion-weighted imaging(DWI)images and apparent diffusion coefficient(ADC)maps are associated with the extent of local invasion(pathological stage T1-2 vs T3-4)and nodal involvement(pathological stage N0 vs N1-2)in rectal cancer.AIM To predict different stages of rectal cancer using texture analysis based on DWI images and ADC maps.METHODS One hundred and fifteen patients with pathologically proven rectal cancer,who underwent preoperative magnetic resonance imaging,including DWI,were enrolled,retrospectively.The ADC measurements(ADCmean,ADCmin,ADCmax)as well as texture features,including the gray level co-occurrence matrix parameters,the gray level run-length matrix parameters and wavelet parameters were calculated based on DWI(b=0 and b=1000)images and the ADC maps.Independent sample t-tests or Mann-Whitney U tests were used for statistical analysis.Multivariate logistic regression analysis was conducted to establish the models.The predictive performance was validated by receiver operating characteristic curve analysis.RESULTS Dissimilarity,sum average,information correlation and run-length nonuniformity from DWIb=0 images,gray level nonuniformity,run percentage and run-length nonuniformity from DWIb=1000 images,and dissimilarity and run percentage from ADC maps were found to be independent predictors of local invasion(stage T3-4).The area under the operating characteristic curve of the model reached 0.793 with a sensitivity of 78.57%and a specificity of 74.19%.Sum average,gray level nonuniformity and the horizontal components of symlet transform(SymletH)from DWIb=0 images,sum average,information correlation,long run low gray level emphasis and SymletH from DWIb=1000 images,and ADCmax,ADCmean and information correlation from ADC maps were identified as independent predictors of nodal involvement.The area under the

关键词： Rectal cancer Diffusion weighted imaging Apparent diffusion coefficient Texture analysis

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Study on positive temperature coefficient of resistivity of co-doped BaTiO_3 with Curie temperature in room temperature region

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Science China(Technological Sciences) 2019年第5期62卷 811-819页

作者： YU AiMei LI Qiang FAN DeSong ZHANG HongLiang MIIT Key Laboratory of Thermal Control of Electronic Equipment School of Energy and Power EngineeringNanjing University of Science & Technology

As a temperature self-regulating heater material, the doped BaTiO_3 exhibits an attractive application perspective in the thermal management of electrical devices. However, the high Curie temperature does not meet the requirement in the thermal control application. In this work,(Ba_(0.997-x)Ce_(0.003)Sr_x)(TiNb_(0.002))O_3(x=0.2, 0.3, 0.35, abbreviated as BCSTNs) ceramics were prepared by the solid-state reaction method. The purpose of doping different content of strontium is to shift the Curie temperature of BaTiO_3-based ceramic to the ambient temperature region, maintaining excellent PT_C effect and low room-temperature resistivity by codoped cation ions in Ba-and Ti-site. The influences of sintering temperature and soak time on the microstructure as well as electrical properties of BCSTNs ceramics have been studied. The X-ray diffraction reveals that the composition with x=0.35 exhibits the coexistence of tetragonal and cubic lattice symmetries, confirmed by the Rietveld structure refinement. The dense microstructure with average grain sizes 0.84–7.87 μm was observed for BCSTN ceramics. Temperature-resistivity measurements demonstrate that T_C of the ceramics with x=0.35 shifted to the room temperature region. Additionally, the BCSTN ceramic with heavy doping Sr exhibits relative low room-temperature resistivity and the resistance jump greater than 2.0 orders of magnitude.

关键词： electrical heating Co-doped BaTiO3 curie temperature positive temperature coefficient of resistivity

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Non-Stokes drag coefficient in single-particle electrophoresis:New insights on a classical problem

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Chinese Physics B 2019年第8期28卷 201-211页

作者：廖麦嘉魏名佐徐士鑫歐陽新喬沈平 Department of Physics Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina Department of Physics Lehigh UniversityBethlehemPAUSA Department of Bioengineering Lehigh UniversityBethlehemPAUSA Centre for Quantitative Analysis and Modelling (CQAM) The Fields InstituteTorontoOntario M5T 3J1Canada

We measured the intrinsic electrophoretic drag coefficient of a single charged particle by optically trapping the particle and applying an AC electric field,and found it to be markedly different from that of the Stokes drag.The drag coefficient,along with the measured electrical force,yield a mobility-zeta potential relation that agrees with the literature.By using the measured mobility as input,numerical calculations based on the Poisson-Nernst-Planck equations,coupled to the Navier-Stokes equation,reveal an intriguing microscopic electroosmotic flow near the particle surface,with a well-defined transition between an inner flow field and an outer flow field in the vicinity of electric double layer’s outer boundary.This distinctive interface delineates the surface that gives the correct drag coefficient and the effective electric charge.The consistency between experiments and theoretical predictions provides new insights into the classic electrophoresis problem,and can shed light on new applications of electrophoresis to investigate biological nanoparticles.

关键词： electrophoresis drag coefficient vortices belt charged colloidal particle

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A tunnel lighting control system based on human vision and variable reduction coefficient

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Optoelectronics Letters 2021年第12期17卷 710-716页

作者：刘默晗刘红 School of Electronics Information Shanghai Dianji UniversityShanghai 201306China

Due to the changeable brightness outside the tunnel,the lighting brightness at the exit and entrance of the tunnel needs to be adjusted in time,so as to ensure that the driver can feel the difference of light intensity within the range that the human eye can adapt to when passing through the tunnel.In this paper,a tunnel lighting control strategy based on variable reduction factor is proposed,which can ensure that the lighting around the tunnel is within the range that the human eye can adapt to at any time.Through the field data collection and comparison and experiments,it can be shown that the lighting control method not only can improve the lighting quality in the tunnel,but also have better energy-saving effect and can reduce the cost of manual operation and maintenance.

关键词： lighting tunnel coefficient

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