检索结果-南通市图书馆

粒子形态对浑浊介质后向散射光偏振特性的影响

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国激光 2020年第1期47卷 196-209页

作者：叶坤涛吉俄木沙翟盛杰江西理工大学理学院江西赣州341000 内华达大学拉斯维加斯分校机械工程系美国拉斯维加斯89154

偏振光在浑浊介质中传输的偏振特性的研究对实现各类偏振光技术具有重要意义。建立一种非球形粒子介质模型,并采用T矩阵法和矢量蒙特卡罗模拟相结合的方法,计算分析含不同非球形粒子的介质中的偏振光经过多次散射形成的后向散射光的偏... 详细信息

偏振光在浑浊介质中传输的偏振特性的研究对实现各类偏振光技术具有重要意义。建立一种非球形粒子介质模型,并采用T矩阵法和矢量蒙特卡罗模拟相结合的方法,计算分析含不同非球形粒子的介质中的偏振光经过多次散射形成的后向散射光的偏振特性。按照介质所含非球形粒子的尺寸分为瑞利散射粒子介质和米氏散射粒子介质。结果表明:瑞利散射粒子介质中,不同粒子形态对线偏振光和圆偏振光的后向散射光的偏振特性的影响不显著,线偏振光保偏能力优于圆偏振光,线偏振方向得到保持,而圆偏振光旋性发生改变;米氏散射粒子介质中,不同粒子形态对后向散射光的偏振特性有显著影响,光学厚度大时,各介质中的圆偏振光保偏能力优于线偏振光,厚度小时线偏振光的保偏能力优于圆偏振光。此外,粒子的形态对偏振光后向散射光偏振度空间分布及光强空间分布均有显著影响。

关键词：散射非球形矢量蒙特卡罗 T矩阵法偏振

在线全文

学校读者我要写书评

暂无评论

受细胞外液扰动的白细胞散射偏振特征

激光与光电子学进展 2019年第5期56卷 197-204页

作者：叶坤涛夏雪婷吉俄木沙江西理工大学理学院医学信息工程研究所江西赣州341000

针对白细胞受细胞外液扰动发生形变的情况,建立了无粒白细胞的椭球核切比雪夫形光学模型。基于T矩阵方法,对线偏振光入射时形态参数及细胞核质比对白细胞散射偏振的影响进行了数值仿真,并与不受细胞外液扰动时的散射偏振特性进行了对比... 详细信息

针对白细胞受细胞外液扰动发生形变的情况,建立了无粒白细胞的椭球核切比雪夫形光学模型。基于T矩阵方法,对线偏振光入射时形态参数及细胞核质比对白细胞散射偏振的影响进行了数值仿真,并与不受细胞外液扰动时的散射偏振特性进行了对比。研究结果表明,在侧向散射区,白细胞散射光线偏振度对外液扰动强度的变化相对于在后向散射区更为敏感,外液扰动越大对偏振的影响越大,且内核形变越大,外液扰动对白细胞散射光偏振的影响越大。

关键词：生物光学细胞分析光散射偏振米勒矩阵白细胞

结合改进显著性检测与NSST的红外与可见光图像融合方法

在线全文

学校读者我要写书评

暂无评论

红外技术 2021年第12期43卷 1212-1221页

作者：叶坤涛李文舒蕾蕾李晟江西理工大学理学院江西赣州341000

针对当前基于显著性检测的红外与可见光图像融合方法存在目标不够突出、对比度低等问题,本文提出了一种结合改进显著性检测与非下采样剪切波变换(non-subsampled shearlet transform,NSST)的融合方法。首先,使用改进最大对称环绕(maximu... 详细信息

针对当前基于显著性检测的红外与可见光图像融合方法存在目标不够突出、对比度低等问题,本文提出了一种结合改进显著性检测与非下采样剪切波变换(non-subsampled shearlet transform,NSST)的融合方法。首先,使用改进最大对称环绕(maximum symmetric surround,MSS)算法提取出红外图像的显著性图,并进一步通过改进伽马校正进行增强,同时应用同态滤波增强可见光图像。然后,对红外图像与增强的可见光图像进行NSST分解,利用显著性图指导低频部分进行融合;同时设定区域能量取大规则指导高频部分融合。最后,通过NSST逆变换重构融合图像。实验结果表明,本文方法在平均梯度、信息熵、空间频率和标准差上远优于其他7种融合方法,可以有效突出红外目标,提高融合图像的对比度和清晰度,并保留可见光图像的丰富背景信息。

关键词：图像融合显著性检测非下采样剪切波变换最大对称环绕同态滤波

在线全文

学校读者我要写书评

暂无评论

非球形气溶胶前向散射对消光的影响

应用激光 2022年第9期42卷 118-125页

作者：叶坤涛费兴明李文舒蕾蕾叶会亮江西理工大学理学院江西赣州341000

非球形气溶胶的前向散射导致太阳辐射计测量消光系数的结果有误差,需要进行前向散射修正。采用T矩阵法,研究了椭球形、圆柱形和切比雪夫形粒子的前向散射特性以及对前向散射修正因子的影响。研究表明,椭球粒子的前向散射强度随着等效半... 详细信息

非球形气溶胶的前向散射导致太阳辐射计测量消光系数的结果有误差,需要进行前向散射修正。采用T矩阵法,研究了椭球形、圆柱形和切比雪夫形粒子的前向散射特性以及对前向散射修正因子的影响。研究表明,椭球粒子的前向散射强度随着等效半径和轴比的增大而增大。沙尘气溶胶粒子中,修正因子会随粒子尺寸参数的增大呈现一个振荡减小的趋势,尺寸参数超过10后,前向散射修正因子将低于0.98,随尺寸参数的增大,修正因子达到0.96左右,不同轴比的椭球粒子和不同长度直径比的圆柱形粒子对修正因子影响较大,切比雪夫粒子的形变参数和波纹参数对修正因子没有明显的影响。研究结果可为大气气溶胶粒子的前向散射研究以及太阳辐射计等相关应用提供理论指导。

关键词：前向散射大气气溶胶 T矩阵散射相函数修正因子

基于高斯模糊逻辑和ADCSCM的红外与可见光图像融合算法

在线全文

学校读者我要写书评

暂无评论

红外技术 2022年第7期44卷 693-701页

作者：李文叶坤涛舒蕾蕾李晟江西理工大学理学院江西赣州341000

为了克服当前的红外与可见光图像融合算法存在着目标不够突出、纹理细节丢失等现象,本文提出了一种基于高斯模糊逻辑和自适应双通道脉冲发放皮层模型(AdaptiveDual-ChannelSpiking CorticalModel,ADCSCM)的红外与可见光图像融合算法。首... 详细信息

为了克服当前的红外与可见光图像融合算法存在着目标不够突出、纹理细节丢失等现象,本文提出了一种基于高斯模糊逻辑和自适应双通道脉冲发放皮层模型(AdaptiveDual-ChannelSpiking CorticalModel,ADCSCM)的红外与可见光图像融合算法。首先,使用非下采样剪切波变换(NonSubsampled Sheartlet Transform, NSST)将源图像分解为低频和高频部分。其次,结合新拉普拉斯能量和(New Sum of Laplacian, NSL)与高斯模糊逻辑,设定双阈值来指导低频部分进行融合;同时,采用基于ADCSCM的融合规则来指导高频部分进行融合。最后,使用NSST逆变换进行重构来获取融合图像。实验结果表明,本文算法主观视觉效果最佳,并在互信息、信息熵和标准差3项指标上高于其他7种融合算法,能够有效突出红外目标、保留较多纹理细节,提高融合图像的质量。

关键词：图像融合非下采样剪切波变换高斯模糊逻辑自适应双通道脉冲发放皮层模型

Investigations of Water Flow Behaviors Induced by Local Temperature Variations through a Single Rough Fracture for the Enhanced Geothermal Systems

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2024年第3期33卷 1055-1064页

作者： LI Jiawei ye Lin Department of Energy and Power Engineering Tsinghua UniversityBeijing100084China School of Power and Energy Northwestern Polytechnical UniversityXi’an710072China

In recent years,Enhanced Geothermal System(EGS)technologies have been applied to the geothermal resources production in the Hot Dry Rock(HDR).The core of EGS technologies is to adopt hydraulic fracturing in the reservoir to create a connected network of discrete fractures with the consideration of water as a working fluid for hydraulic fracturing and heat *** paper investigates the characteristics of water flow behaviors through a single rough fracture under different temperature and pressure conditions.A single fracture model with rough fracture surfaces is constructed and then characterized,and influences of the anisotropic factor on the average tortuosity and frictional resistance coefficient of water flow through a single fracture with rough surfaces have been compared and *** consideration of other impacting factors(temperature,pressure,fracture roughness),the impact of mass flow rate has also been *** simulation results present that changes of average tortuosity for water flow through a single rough facture are mainly affected by *** can be observed that higher temperature leads to larger average tortuosity but the frictional resistance coefficient shows an opposite *** for pressure conditions,it is found that effects of pressure on average tortuosity and frictional resistance coefficient is very small,which can be neglected under high pressure ***,the average tortuosity shows a progressively linear relationship with the mass flow *** the contrary,the frictional resistance coefficient has a negative relationship with the mass flow *** is revealed that when the mass flow rate reaches a critical point,the influences of temperature on the frictional resistance coefficient will be *** of single rough fractures with different anisotropic factors show that values of average tortuosity and frictional resistance coefficient have positive relationships with the increase

关键词： single rough fracture tortuosity frictional resistance enhanced geothermal system

Path-Dependent Progressive Failure Analysis for 3D-Printed Continuous Carbon Fibre Reinforced Composites

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2024年第4期37卷 84-93页

作者： Yuan Chen Lin ye School of System Design and Intelligent Manufacturing(SDIM) Southern University of Science and TechnologyShenzhen 518055China Shenzhen Key Laboratory of Intelligent Manufacturing for Continuous Carbon Fibre Reinforced Composites Southern University of Science and TechnologyShenzhen 518055China

In order to predict the damage behaviours of 3D-printed continuous carbon fibre(CCF)reinforced composites,when additional short carbon fibre(SCF)composite components are employed for continuous printing or special functionality,a novel path-dependent progressive failure(PDPF)numerical approach is ***,a progressive failure model using Hashin failure criteria with continuum damage mechanics to account for the damage initiation and evaluation of 3D-printed CCF reinforced polyamide(PA)composites is developed,based on actual fibre placement trajectories with physical measurements of 3D-printed CCF/PA ***,an elastic-plastic model is employed to predict the plastic damage behaviours of SCF/PA ***,the accuracy of the PDPF model was validated so as to study 3D-printed CCF/PA composites with either negative Poisson's ratio or high *** results demonstrate that the proposed PDPF model can achieve higher prediction accuracies in mechanical properties of these 3D-printed CCF/PA *** analyses show that the stress distribution is generally aggregated in the CCF areas along the fibre placement paths,and the shear damage and matrix tensile/compressive damage are the key damage *** study provides a new approach with valuable information for characterising complex 3D-printed continuous fibre-matrix composites with variable mechanical properties and multiple constituents.

关键词： 3D printing Continuous carbon fibre Modelling Energy absorption Negative Poisson's ratio

在线全文

学校读者我要写书评

暂无评论

静电驱动MEMS扭转微镜系统的分岔与吸合

江西理工大学学报 2017年第3期38卷 103-110页

作者：叶坤涛罗艳江西理工大学理学院江西赣州341000

建立了静电驱动的双下极板MEMS扭转微镜系统的动力学模型方程,通过其状态空间方程的数值解,在相空间对静态及动态的分岔现象、吸合特性进行分析,并利用哈密顿函数法在阻尼为零时与相空间分析结果进行了对比验证.研究表明,双下极板扭转... 详细信息

建立了静电驱动的双下极板MEMS扭转微镜系统的动力学模型方程,通过其状态空间方程的数值解,在相空间对静态及动态的分岔现象、吸合特性进行分析,并利用哈密顿函数法在阻尼为零时与相空间分析结果进行了对比验证.研究表明,双下极板扭转微镜系统中观察到的鞍结分岔、叉式分岔与系统的吸合失稳之间有明显的对应关系;在对系统动态特性分析的过程中,随阻尼变化观察到动态霍夫分岔;微镜系统动态吸合电压总小于静态吸合电压,且随阻尼、电压比升高;动态吸合电压随阻尼增大并最终接近饱和,饱和值为静态吸合电压;在相同的驱动电压下,最大偏转角随阻尼的升高而降低.研究方法和结论对静电驱动的扭转微镜系统的分析有借鉴作用.

关键词： MEMS 相图分岔吸合哈密顿

A modified stochastic model for LS+AR hybrid method and its application in polar motion short-term prediction

在线全文

学校读者我要写书评

暂无评论

Geodesy and Geodynamics 2024年第1期15卷 100-105页

作者： Fei ye Yunbin Yuan State Key Laboratory of Geodesy and Earth's Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430077China BeiDou High-precision Satellite Navigation and Location Service Hunan Engineering Research Center Hunan Institute of Geomatics Sciences and TechnologyChangsha 410007China Hunan Continuously Operating Reference Stations(HNCORS)Data Center Hunan Institute of Geomatics Sciences and TechnologyChangsha 410007China

Short-term(up to 30 days)predictions of Earth Rotation Parameters(ERPs)such as Polar Motion(PM:PMX and PMY)play an essential role in real-time applications related to high-precision reference frame ***,least squares(LS)+auto-regressive(AR)hybrid method is one of the main techniques of PM ***,the weighted LS+AR hybrid method performs well for PM short-term ***,the corresponding covariance information of LS fitting residuals deserves further exploration in the AR *** this study,we have derived a modified stochastic model for the LS+AR hybrid method,namely the weighted LS+weighted AR hybrid *** using the PM data products of IERS EOP 14 C04,the numerical results indicate that for PM short-term forecasting,the proposed weighted LS+weighted AR hybrid method shows an advantage over both the LS+AR hybrid method and the weighted LS+AR hybrid *** to the mean absolute errors(MAEs)of PMX/PMY sho rt-term prediction of the LS+AR hybrid method and the weighted LS+AR hybrid method,the weighted LS+weighted AR hybrid method shows average improvements of 6.61%/12.08%and 0.24%/11.65%,***,for the slopes of the linear regression lines fitted to the errors of each method,the growth of the prediction error of the proposed method is slower than that of the other two methods.

关键词： Stochastic model LS+AR Short-term prediction The earth rotation parameter(ERP) Observation model