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A New Inversion-free Iterative Method for Solving the Nonlinear Matrix Equation and Its Application in Optimal Control
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作者 GAO Xiangyu XIE Weiwei ZHANG Lina 《应用数学》 北大核心 2026年第1期143-150,共8页
In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to ... In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to obtain the maximal positive definite solution of nonlinear matrix equation X+A^(*)X|^(-α)A=Q with the case 0<α≤1.Based on this method,a new iterative algorithm is developed,and its convergence proof is given.Finally,two numerical examples are provided to show the effectiveness of the proposed method. 展开更多
关键词 Nonlinear matrix equation Maximal positive definite solution Inversion-free iterative method Optimal control
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A Cost-Effective Approach to Precisely Estimate Singlet-Triplet Energy Gaps in MR-TADF Molecules:Combining Delta Self-Consistent Field and Time-Dependent Density Functional Theory Methods
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作者 Qian Jina Dong Wang 《Chinese Journal of Chemical Physics》 2026年第1期41-50,I0021-I0032,I0042,共23页
As a novel class of purely organic fluores-cent materials,multiple resonance thermal-ly activated delayed fluorescence(MR-TADF)compounds hold significant promise for next-generation display technologies.The efficiency... As a novel class of purely organic fluores-cent materials,multiple resonance thermal-ly activated delayed fluorescence(MR-TADF)compounds hold significant promise for next-generation display technologies.The efficiency of exciton utilization and the overall performance of organic light-emit-ting devices are closely linked to the singlet-triplet energy gap(ΔE_(ST))of MR-TADF emitters.Identifying an economic and accu-rate theoretical approach to predictΔE_(ST)would be beneficial for high-throughput screening and facilitate the inverse design of MR-TADF molecules.In this study,we evaluated the S_(1)state energy(E(S_(1))),T_(1)state ener-gy(E(T_(1))),andΔE_(ST)using three different physical interpretations:adiabatic excitation ener-gy,vertical absorption energy,and vertical emission energy.We employed the time-depen-dent density functional theory(TDDFT)and delta self-consistent field(ΔSCF)methods to calculate E(S_(1)),E(T_(1)),andΔE_(ST)for 20 MR-TADF molecules reported in the literature.We compared these calculated values with experimental data obtained from fluorescence spec-troscopy at room-temperature(or 77 K)and phosphorescence spectroscopy conducted at 77 K.Our findings indicate that the vertical absorption energy at the S0 state minimum,deter-mined by theΔSCF method,accurately predicts the S_(1)state energy.Similarly,the vertical absorption energy at the S0 state minimum,calculated using the TDDFT method,effectively predicts the T_(1)state energy.TheΔE_(ST)derived from the difference between these two excita-tion energies exhibited the smallest mean absolute error of only 0.039 eV compared to the ex-perimental values.This combination represents the most accurate and cost-effective method reported to date for predicting theΔE_(ST)of MR-TADF molecules,and can be integrated into AI-driven inverse design workflows for new emitters. 展开更多
关键词 Organic light-emitting diode Multiple resonance thermally activated delayed fluorescence emitter Single-triplet energy gap Delta self-consistent field method time-de-pendent density functional theory method
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A dense mesh optimization method for accelerating electrostatic interaction computation of non-cooperative space targets
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作者 Heng JING Zixuan ZHENG +3 位作者 Dejia CHE Da ZHANG Shulong LI Jianping YUAN 《Chinese Journal of Aeronautics》 2026年第2期499-516,共18页
Computing electrostatic interaction on non-cooperative targets with unknown meshes is crucial for electrostatic-based space on-orbit services.Although meshes for electrostatic interaction computations can be reconstru... Computing electrostatic interaction on non-cooperative targets with unknown meshes is crucial for electrostatic-based space on-orbit services.Although meshes for electrostatic interaction computations can be reconstructed from point clouds,they are usually too dense,leading to high computational costs.This paper presents an optimization method for converting dense meshes into optimal meshes,enabling fast and accurate computation of the electrostatic interaction by point clouds.First,the dense mesh reconstructed from point clouds is simplified into a coarse mesh using local operators.Second,the simplified mesh is refined by an iterative strategy that integrates a lightweight method of moments and an impedance matrix inheritance technique,ultimately yielding an optimal mesh for computing the electrostatic interaction.Simulation results show that our method effectively optimizes dense meshes,making electrostatic interaction computations using point clouds approximately 63.4 times more efficient than the previous method. 展开更多
关键词 Non-cooperative target Electrostatic interaction method of moments Point cloud Mesh optimization
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Two-Scale Concurrent Topology Optimization Method Based on Boundary Connection Layer Microstructure
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作者 Hongyu Xu Xiaofeng Liu +5 位作者 Zhao Li Shuai Zhang Jintao Cui Zongshuai Zhou Longlong Chen Mengen Zhang 《Computers, Materials & Continua》 2026年第5期347-372,共26页
In two-scale topology optimization,enhancing the connectivity between adjacent microstructures is crucial for achieving the collaborative optimization of micro-scale performance and macro-scale manufacturability.This ... In two-scale topology optimization,enhancing the connectivity between adjacent microstructures is crucial for achieving the collaborative optimization of micro-scale performance and macro-scale manufacturability.This paper proposes a two-scale concurrent topology optimization strategy aimed at improving the interface connection strength.This method employs a parametric approach to explicitly divide the micro-design domain into a“boundary connection region”and a“free design domain”at the initial stage of optimization.The boundary connection region is used to generate a connection layer that enhances the interface strength,while the free design domain is not constrained by this layer,thus fully exploiting the design potential of the material layout.During the optimization process,the solid isotropic material with penalization(SIMP)method is first used to optimize the material distribution in the free design domain,and filtering and projection techniques are employed to alleviate numerical instability and obtain a clear topological structure.Subsequently,the effective performance of the microstructure is calculated through homogenization and transferred to the macro-scale for global response analysis.Throughout the iterative process,the geometry of the connection layer remains unchanged,and only the free design domain is optimized,thereby achieving a balance between high performance and good manufacturability.The effectiveness of the proposed method is verified through numerical examples. 展开更多
关键词 Two-scale topology optimization connectable microstructure interface connectivity boundary connection layer SIMP method homogenization theory
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Validation of time-space collocation method for simulating asymmetric unsteady flows in eccentric compressors
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作者 Haowei ZHOU Pengcheng DU Fangfei NING 《Chinese Journal of Aeronautics》 2026年第2期80-99,共20页
Circumferentially non-uniform tip clearances induced by rotor eccentricity significantly affect the overall performance of axial compressors,particularly the stability margin.Currently,Computational Fluid Dynamics(CFD... Circumferentially non-uniform tip clearances induced by rotor eccentricity significantly affect the overall performance of axial compressors,particularly the stability margin.Currently,Computational Fluid Dynamics(CFD)plays a crucial role in the aerodynamic analysis of eccentric compressors.However,conventional full-annulus Unsteady Reynolds-Averaged Navier-Stokes(URANS)simulations are prohibitively expensive for routine design and analysis purposes.To address this issue,the paper presents a novel Fourier-based method,called the Time-Space Collocation(TSC)method,for efficient simulations of eccentric compressors.This method coherently treats temporal and spatial harmonics,making it well-suited to tackle the rotor eccentricity problem,as the perturbation waves induced by eccentricity are time-periodic with respect to the rotor and space-periodic with respect to the stator.Three numerical cases,including NASA Rotor 67,original Stage 67,and Stage 67 with a reduced rotor-stator axial gap,were conducted to verify the effectiveness of the TSC method.The results indicate that,for the rotor eccentricity levels studied in this paper,the influence of weak rotor-stator interactions can be disregarded in the original Stage 67.In this situation,applying three harmonics can accurately capture both the performance variations and the non-uniformly distributed flowfields of eccentric compressors,while achieving a reduction in run time by two orders of magnitude compared to full-annulus URANS simulations.However,in Stage 67 with a reduced rotor-stator axial gap,the results that include rotor-stator interactions align much more closely with the URANS results.Nevertheless,the TSC simulations can still achieve speed-ups of several dozen times.Overall,the TSC method shows promising potential for application within the engineering community. 展开更多
关键词 Circumferentially nonuniform tip clearance Full-annulus unsteady simulation Rotor eccentricity time-space collocation method time-space periodic flow
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Precision and trueness of a method for determing antimony content in groundwater using hydride generation-atomic fluorescence spectrometry
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作者 Bing-bing Liu Lin Zhang Ke Li 《Journal of Groundwater Science and Engineering》 2026年第1期49-58,共10页
At present,there is currently a lack of unified standard methods for the determination of antimony content in groundwater in China.The precision and trueness of related detection technologies have not yet been systema... At present,there is currently a lack of unified standard methods for the determination of antimony content in groundwater in China.The precision and trueness of related detection technologies have not yet been systematically and quantitatively evaluated,which limits the effective implementation of environmental monitoring.In response to this key technical gap,this study aimed to establish a standardized method for determining antimony in groundwater using Hydride Generation–Atomic Fluorescence Spectrometry(HG-AFS).Ten laboratories participated in inter-laboratory collaborative tests,and the statistical analysis of the test data was carried out in strict accordance with the technical specifications of GB/T 6379.2—2004 and GB/T 6379.4—2006.The consistency and outliers of the data were tested by Mandel's h and k statistics,the Grubbs test and the Cochran test,and the outliers were removed to optimize the data,thereby significantly improving the reliability and accuracy.Based on the optimized data,parameters such as the repeatability limit(r),reproducibility limit(R),and method bias value(δ)were determined,and the trueness of the method was statistically evaluated.At the same time,precision-function relationships were established,and all results met the requirements.The results show that the lower the antimony content,the lower the repeatability limit(r)and reproducibility limit(R),indicating that the measurement error mainly originates from the detection limit of the method and instrument sensitivity.Therefore,improving the instrument sensitivity and reducing the detection limit are the keys to controlling the analytical error and improving precision.This study provides reliable data support and a solid technical foundation for the establishment and evaluation of standardized methods for the determination of antimony content in groundwater. 展开更多
关键词 Mandel's h and k statistics Grubbs test Cochran test Repeatability limit Reproducibility limit method bias value
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结直肠癌组织中TIM3、SIAH1的表达特征及其与预后的关系
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作者 李志强 高静 +3 位作者 姚远 李小成 常畅 闫玉洁 《河北医科大学学报》 2026年第2期163-170,共8页
目的探讨结直肠癌(colorectal cancer,CRC)组织中T细胞免疫球蛋白黏蛋白3(T cell immunoglobulin and mucin domain-containing protein 3,TIM3)、E3泛素蛋白连接酶-1(seven in absentia homolog-1,SIAH1)的表达特征及其与预后的关系。... 目的探讨结直肠癌(colorectal cancer,CRC)组织中T细胞免疫球蛋白黏蛋白3(T cell immunoglobulin and mucin domain-containing protein 3,TIM3)、E3泛素蛋白连接酶-1(seven in absentia homolog-1,SIAH1)的表达特征及其与预后的关系。方法选取2019年6月―2022年3月在河北北方学院附属第二医院住院手术的CRC患者148例为研究对象,收集整理CRC患者临床资料,免疫组化法检测TIM3、SIAH1蛋白表达;Spearman法分析CRC组织TIM3与SIAH1表达之间的相关性;CRC组织TIM3、SIAH1与患者预后关系用Kaplan-Meier法分析;Cox回归分析影响预后的因素。结果UALCAN数据库中,癌组织中TIM3阳性表达率(53.19%)高于正常组织(15.79%),癌组织中SIAH1阳性表达率(33.64%)低于正常组织(60.71%)(P<0.05);免疫组织化学检测结果中,TIM3阳性表达率(70.95%)高于癌旁组织(38.51%),SIAH1阳性表达率(33.11%)低于癌旁组织(62.16%),差异有统计学意义(P<0.05);TIM3、SIAH1表达与CRC患者分化程度、临床分期以及淋巴结转移均有关(P<0.05);Spearman相关分析得出,CRC组织TIM3、SIAH1表达呈负相关(r=―0.435,P<0.05);CRC组织TIM3阳性表达患者3年生存率(54/105,51.43%)低于TIM3阴性表达患者(37/43,86.05%)(Log Rankχ^(2)=15.183,P<0.001);TIM3阳性组中位生存期为28.124个月(95%CI:26.220~30.028),短于TIM3阴性组的33.628个月(95%CI:31.818~35.437);CRC组织SIAH1阳性表达患者3年生存率(43/49,87.76%)高于SIAH1阴性表达患者(48/99,48.48%)(Log Rankχ^(2)=21.016,P<0.001),SIAH1阳性组中位生存期为34.76个月(95%CI:33.644~35.907)长于SIAH1阴性组的27.222个月(95%CI:25.219~29.225);分化程度(HR=2.457,95%CI:1.133~5.329)、临床分期(HR=2.861,95%CI:1.364~6.002)淋巴结转移(HR=2.729,95%CI:1.382~5.387)以及TIM3(HR=3.562,95%CI:1.833~6.922)、SIAH1(HR=0.613,95%CI:0.470~0.799)是影响预后的因素(P<0.05)。结论TIM3、SIAH1在CRC组织中呈现不同的表达特征,且其表达水平与患者预后有关。 展开更多
关键词 结直肠肿瘤 tim3 SIAH1 预后
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广州地球化学研究所ID-TIMS实验室单颗粒锆石U-Pb定年的低本底与高精度分析
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作者 钟玉婷 Amelin Yuri 徐义刚 《地球化学》 北大核心 2026年第2期208-218,共11页
高精度地质年代学可为理解地球演化历史提供高分辨率时间标尺。单颗粒锆石化学溶蚀–同位素稀释–热电离质谱法(CA-ID-TIMS)定年技术作为国际公认的定年“金标准”,其技术发展水平直接制约对关键地质事件时序的精确解析能力。本文系统... 高精度地质年代学可为理解地球演化历史提供高分辨率时间标尺。单颗粒锆石化学溶蚀–同位素稀释–热电离质谱法(CA-ID-TIMS)定年技术作为国际公认的定年“金标准”,其技术发展水平直接制约对关键地质事件时序的精确解析能力。本文系统介绍了中国科学院广州地球化学研究所ID-TIMS U-Pb年代学实验室在平台建设、分析方法与全流程Pb本底控制以及高精度定年方面的最新进展。通过引进国内首台配备ATONA专利放大器的Isotopx Phoenix热电离质谱仪,建立了以静态多接收为主的锆石U-Pb同位素分析流程,显著提升了分析精度与效率。通过系统优化洁净实验环境与实验材料处理流程,目前全流程Pb本底稳定控制在<0.70 pg,达到国际公认的ID-TIMS实验室准入标准,处于国内领先水平。对EARTHTIME合成溶液标样ET100的多流程验证显示,在直接点样、平行样测试与U-Pb化学分离三种处理方式下,^(206)Pb/^(238)U年龄测定结果均呈现良好的一致性(加权平均年龄为100.320±0.005 Ma),外精度为0.017%(2RSD)。采用所建立的分析流程对锆石标样R33与TEMORA 2进行测定,所获年龄与国际推荐值一致,表明本实验室已具备产出高精度、高重现性U-Pb年龄数据的能力。未来,实验室将持续优化本底控制,完善锆石微量元素与Hf同位素配套分析方法,并积极与国内外同行合作,力争为我国深时地质研究、关键地层定年与重大地质事件时序的精确框架构建提供可靠的技术支撑。 展开更多
关键词 高精度地质年代学 ID-timS 锆石U-PB定年 地时计划 本底控制
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Design and optimization of the RGB beam combiner in micro display using entropy weight-TOPSIS method 被引量:1
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作者 ZHENG Yu ZHAO Yan-bing +4 位作者 ZOU Xin-jie WANG Ji-rong JIANG Xiang LIU Jian-zhe DUAN Ji-an 《Journal of Central South University》 2025年第2期483-494,共12页
Red-green-blue(RGB)beam combiners are widely used in scenarios such as augmented reality/virtual reality(AR/VR),laser projection,biochemical detection,and other fields.Optical waveguide combiners have attracted extens... Red-green-blue(RGB)beam combiners are widely used in scenarios such as augmented reality/virtual reality(AR/VR),laser projection,biochemical detection,and other fields.Optical waveguide combiners have attracted extensive attention due to their advantages of small size,high multiplexing efficiency,convenient mass production,and low cost.An RGB beam combiner based on directional couplers is designed,with a core-cladding relative refractive index difference of 0.75%.The RGB beam combiner is optimized from the perspective of parameter optimization.Using the beam propagation method(BPM),the relationship between the performance of the RGB beam combiner and individual parameters is studied,achieving preliminary optimization of the device’s performance.The key parameters of the RGB beam combiner are optimized using the entropy weight-technique for order preference by similarity to an ideal solution TOPSIS method,establishing the optimal parameter scheme and further improving the device’s performance indicators.The results show that after optimization,the multiplexing efficiencies for red,green,and blue lights,as well as the average multiplexing efficiency,reached 99.17%,99.76%,96.63%and 98.52%,respectively.The size of the RGB beam combiner is 4.768 mm×0.062 mm. 展开更多
关键词 optical waveguide combiners red-green-blue beam combiner beam propagation method entropy weight TOPSIS method multiplexing efficiency
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Accumulative-Error-Based Event-Triggered Control for Discrete-Time Linear Systems:A Discrete-Time Looped Functional Method 被引量:2
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作者 Xian-Ming Zhang Qing-Long Han +1 位作者 Xiaohua Ge Bao-Lin Zhang 《IEEE/CAA Journal of Automatica Sinica》 2025年第4期683-693,共11页
This paper is concerned with event-triggered control of discrete-time systems with or without input saturation.First,an accumulative-error-based event-triggered scheme is devised for control updates.When the accumulat... This paper is concerned with event-triggered control of discrete-time systems with or without input saturation.First,an accumulative-error-based event-triggered scheme is devised for control updates.When the accumulated error between the current state and the latest control update exceeds a certain threshold,an event is triggered.Such a scheme can ensure the event-generator works at a relatively low rate rather than falls into hibernation especially after the system steps into its steady state.Second,the looped functional method for continuous-time systems is extended to discrete-time systems.By introducing an innovative looped functional that links the event-triggered scheme,some sufficient conditions for the co-design of control gain and event-triggered parameters are obtained in terms of linear matrix inequalities with a couple of tuning parameters.Then,the proposed method is applied to discrete-time systems with input saturation.As a result,both suitable control gains and event-triggered parameters are also co-designed to ensure the system trajectories converge to the region of attraction.Finally,an unstable reactor system and an inverted pendulum system are given to show the effectiveness of the proposed method. 展开更多
关键词 Discrete-time linear systems event-triggered control input saturation looped functional method
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A body-fitted adaptive mesh and Helmholtz-type filter based parameterized level-set method for structural topology optimization 被引量:1
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作者 Yijie Lu Xueying Chang +3 位作者 Zhengwei Zhang Hui Liu Yanguo Zhou Hao Li 《Acta Mechanica Sinica》 2025年第5期131-147,共17页
Parameterized level-set method(PLSM)has been proposed and developed for many years,and is renowned for its efficacy in ad-dressing topology optimization challenges associated with intricate boundaries and nucleation o... Parameterized level-set method(PLSM)has been proposed and developed for many years,and is renowned for its efficacy in ad-dressing topology optimization challenges associated with intricate boundaries and nucleation of new holes.However,most pertinent investigations in the field rely predominantly on fixed background mesh,which is never remeshed.Consequently,the mesh element partitioned by material interface during the optimization process necessitates approximation by using artificial interpolation models to obtain its element stiffness or other properties.This paper introduces a novel approach to topology op-timization by integrating the PLSM with body-fitted adaptive mesh and Helmholtz-type filter.Primarily,combining the PLSM with body-fitted adaptive mesh enables the regeneration of mesh based on the zero level-set interface.This not only precludes the direct traversal of the material interface through the mesh element during the topology optimization process,but also improves the accuracy of calculation.Additionally,the incorporation of a Helmholtz-type partial differential equation filter,relying solely on mesh information essential for finite element discretization,serves to regulate the topological complexity and the minimum feature size of the optimized structure.Leveraging these advantages,the topology optimization program demonstrates its versa-tility by successfully addressing various design problems,encompassing the minimum mean compliance problem and minimum energy dissipation problem.Ultimately,the result of numerical example indicates that the optimized structure exhibits a dis-tinct and smooth boundary,affirming the effective control over both topological complexity and the minimum feature size of the optimized structure. 展开更多
关键词 Topology optimization Parameterized level-set method Helmholtz-type filter Body-fitted adaptive mesh
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A New Method to Calculate Nonlinear Optimal Perturbations for Ensemble Forecasting 被引量:1
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作者 Junjie MA Wansuo DUAN +1 位作者 Zhuomin LIU Ye WANG 《Advances in Atmospheric Sciences》 2025年第5期952-967,共16页
Orthogonal conditional nonlinear optimal perturbations(O-CNOPs)have been used to generate ensemble forecasting members for achieving high forecasting skill of high-impact weather and climate events.However,highly effi... Orthogonal conditional nonlinear optimal perturbations(O-CNOPs)have been used to generate ensemble forecasting members for achieving high forecasting skill of high-impact weather and climate events.However,highly efficient calculations for O-CNOPs are still challenging in the field of ensemble forecasting.In this study,we combine a gradient-based iterative idea with the Gram‒Schmidt orthogonalization,and propose an iterative optimization method to compute O-CNOPs.This method is different from the original sequential optimization method,and allows parallel computations of O-CNOPs,thus saving a large amount of computational time.We evaluate this method by using the Lorenz-96 model on the basis of the ensemble forecasting ability achieved and on the time consumed for computing O-CNOPs.The results demonstrate that the parallel iterative method causes O-CNOPs to yield reliable ensemble members and to achieve ensemble forecasting skills similar to or even slightly higher than those produced by the sequential method.Moreover,the parallel method significantly reduces the computational time for O-CNOPs.Therefore,the parallel iterative method provides a highly effective and efficient approach for calculating O-CNOPs for ensemble forecasts.Expectedly,it can play an important role in the application of the O-CNOPs to realistic ensemble forecasts for high-impact weather and climate events. 展开更多
关键词 initial uncertainty conditional nonlinear optimal perturbation optimization method ensemble forecasting
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Study on the operating characteristics of Stirling engine based on an optimized analysis method 被引量:1
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作者 Shang-Dong Yang Wen-Pei Feng +1 位作者 Yu-Gao Ma Zhi-Xing Gu 《Nuclear Science and Techniques》 2025年第9期209-225,共17页
The Stirling engine,as a closed-cycle power machine,exhibits excellent emission characteristics and broad energy adaptability.Second-order analysis methods are extensively used during the foundational design and therm... The Stirling engine,as a closed-cycle power machine,exhibits excellent emission characteristics and broad energy adaptability.Second-order analysis methods are extensively used during the foundational design and thermodynamic examination of Stirling engines,owing to their commendable model precision and remarkable efficiency.To scrutinize the effect of Stirling engine design parameters on the cyclical work output and efficiency,this study formulates a series of differential equations for the Stirling cycle by employing second-order analysis methods,subsequently augmenting the predictive accuracy by integrating considerations of loss mechanisms.In addition,an iterative method for the convergence of the average pressure was introduced.The predictive capability of the established model was validated using GPU-3 and RE-1000 experimental data.According to the model,parameters such as the operational fluid,porosity of the regenerator,and diameter of the wire mesh and their influence on the resulting work output and cyclic efficiency of the Stirling engine were analyzed,thereby facilitating a broader understanding of the engine's functional characteristics.These findings suggest that hydrogen,owing to its lower dynamic viscosity coefficient,can provide superior output power.The loss due to flow resistance tends to increase with the rotational speed.Additionally,under conditions of elevated rotational speed,the loss from flow resistance declines in cases of increased porosity,and the enhancement of the porosity to diminish flow resistance losses can boost both the output work and the cyclic efficiency of the engine.As the porosity increased further,the hydraulic diameter and dead volume in the regenerator continued to expand,causing the pressure drop within the engine to become the dominant factor in the gradual reduction of output power.Furthermore,extending the length of the regenerator results in a decrease in the output work,although the thermal cycle efficiency initially increases before eventually decreasing.Based on these insights,this study pursues the optimal designs for Stirling engines. 展开更多
关键词 Stirling engine Second-order method Operating characteristics Mechanisms of loss Cyclic efficiency
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Photometry-free sky area visibility estimation method for All-sky Camera 被引量:1
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作者 Haiwen Xie Hui Zhi +4 位作者 Zhe Kang Shiyu Deng Bingli Niu Lei Wang Xiaojun Jiang 《Astronomical Techniques and Instruments》 2025年第1期52-64,共13页
Observatories typically deploy all-sky cameras for monitoring cloud cover and weather conditions.However,many of these cameras lack scientific-grade sensors,r.esulting in limited photometric precision,which makes calc... Observatories typically deploy all-sky cameras for monitoring cloud cover and weather conditions.However,many of these cameras lack scientific-grade sensors,r.esulting in limited photometric precision,which makes calculating the sky area visibility distribution via extinction measurement challenging.To address this issue,we propose the Photometry-Free Sky Area Visibility Estimation(PFSAVE)method.This method uses the standard magnitude of the faintest star observed within a given sky area to estimate visibility.By employing a pertransformation refitting optimization strategy,we achieve a high-precision coordinate transformation model with an accuracy of 0.42 pixels.Using the results of HEALPix segmentation is also introduced to achieve high spatial resolution.Comprehensive analysis based on real allsky images demonstrates that our method exhibits higher accuracy than the extinction-based method.Our method supports both manual and robotic dynamic scheduling,especially under partially cloudy conditions. 展开更多
关键词 All-sky cameras Astronomy image processing Ground-based astronomy Calibration Computational methods Observational astronomy
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Estimation of Chloride Diffusivity in Hydrated Tricalcium Silicate Using a Hydration-Diffusion Integrated Method
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作者 WANG Xin SHEN Dejian +2 位作者 TAO Sijie LIU Ruixin WU Shengxing 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2025年第1期49-64,共16页
This study aims to develop a chloride diffusion simulation method that considers the hydration microstructure and pore solution properties during the hydration of tricalcium silicate(C3S).The method combines the hydra... This study aims to develop a chloride diffusion simulation method that considers the hydration microstructure and pore solution properties during the hydration of tricalcium silicate(C3S).The method combines the hydration simulation,thermodynamic calculation,and finite element analysis to examine the effects of pore solution,including effect of electrochemical potential,effect of chemical activity,and effect of mechanical interactions between ions,on the chloride effective diffusion coefficient of hydrated C3S paste.The results indicate that the effect of electrochemical potential on chloride diffusion becomes stronger with increasing hydration age due to the increase in the content of hydrated calcium silicate;as the hydration age increases,the effect of chemical activity on chloride diffusion weakens when the number of diffusible elements decreases;the effect of mechanical interactions between ions on chloride diffusion decreases with the increase of hydration age. 展开更多
关键词 tricalcium silicate simulation method chloride diffusion coefficient pore solution
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Optimal Scheduling of an Independent Electro-Hydrogen System with Hybrid Energy Storage Using a Multi-Objective Standardization Fusion Method
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作者 Suliang Ma Zeqing Meng +1 位作者 Mingxuan Chen Yuan Jiang 《Energy Engineering》 EI 2025年第1期63-84,共22页
In the independent electro-hydrogen system(IEHS)with hybrid energy storage(HESS),achieving optimal scheduling is crucial.Still,it presents a challenge due to the significant deviations in values ofmultiple optimizatio... In the independent electro-hydrogen system(IEHS)with hybrid energy storage(HESS),achieving optimal scheduling is crucial.Still,it presents a challenge due to the significant deviations in values ofmultiple optimization objective functions caused by their physical dimensions.These deviations seriously affect the scheduling process.A novel standardization fusion method has been established to address this issue by analyzing the variation process of each objective function’s values.The optimal scheduling results of IEHS with HESS indicate that the economy and overall energy loss can be improved 2–3 times under different optimization methods.The proposed method better balances all optimization objective functions and reduces the impact of their dimensionality.When the cost of BESS decreases by approximately 30%,its participation deepens by about 1 time.Moreover,if the price of the electrolyzer is less than 15¥/kWh or if the cost of the fuel cell drops below 4¥/kWh,their participation will increase substantially.This study aims to provide a more reasonable approach to solving multi-objective optimization problems. 展开更多
关键词 Electro-hydrogen system multi-objective optimization standardization method hybrid energy storage system
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Topology Optimization of Orthotropic Materials Using the Improved Element-Free Galerkin (IEFG) Method
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作者 Wenna He Yichen Yang +1 位作者 Dongqiong Liang Heng Cheng 《Computers, Materials & Continua》 2025年第4期1415-1437,共23页
In this paper,we develop an advanced computational framework for the topology optimization of orthotropic materials using meshless methods.The approximation function is established based on the improved moving least s... In this paper,we develop an advanced computational framework for the topology optimization of orthotropic materials using meshless methods.The approximation function is established based on the improved moving least squares(IMLS)method,which enhances the efficiency and stability of the numerical solution.The numerical solution formulas are derived using the improved element-free Galerkin(IEFG)method.We introduce the solid isotropic microstructures with penalization(SIMP)model to formulate a mathematical model for topology opti-mization,which effectively penalizes intermediate densities.The optimization problem is defined with the numerical solution formula and volume fraction as constraints.The objective function,which is the minimum value of flexibility,is optimized iteratively using the optimization criterion method to update the design variables efficiently and converge to an optimal solution.Sensitivity analysis is performed using the adjoint method,which provides accurate and efficient gradient information for the optimization algorithm.We validate the proposed framework through a series of numerical examples,including clamped beam,cantilever beam,and simply supported beam made of orthotropic materials.The convergence of the objective function is demonstrated by increasing the number of iterations.Additionally,the stability of the iterative process is analyzed by examining the fluctuation law of the volume fraction.By adjusting the parameters to an appropriate range,we achieve the final optimization results of the IEFG method without the checkerboard phenomenon.Comparative studies between the Element-Free Galerkin(EFG)and IEFG methods reveal that both methods yield consistent optimization results under identical parameter settings.However,the IEFG method significantly reduces computational time,highlighting its efficiency and suitability for orthotropic materials. 展开更多
关键词 Solid isotropic microstructures with penalization method variable density method sensitivity analysis improved element-free Galerkin method meshless method
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Optimal Error Estimates of Multiphysics Finite Element Method for a Nonlinear Poroelasticity Model with Nonlinear Stress-Strain Relation
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作者 GE Zhi-hao LI Hai-run LI Ting-ting 《Chinese Quarterly Journal of Mathematics》 2025年第3期271-294,共24页
In this paper,we propose a multiphysics finite element method for a nonlinear poroelasticity model with nonlinear stress-strain relation.Firstly,we reformulate the original problem into a new coupled fluid system-a ge... In this paper,we propose a multiphysics finite element method for a nonlinear poroelasticity model with nonlinear stress-strain relation.Firstly,we reformulate the original problem into a new coupled fluid system-a generalized nonlinear Stokes problem of displacement vector field related to pseudo pressure and a diffusion problem of other pseudo pressure fields.Secondly,a fully discrete multiphysics finite element method is performed to solve the reformulated system numerically.Thirdly,existence and uniqueness of the weak solution of the reformulated model and stability analysis and optimal convergence order for the multiphysics finite element method are proven theoretically.Lastly,numerical tests are given to verify the theoretical results. 展开更多
关键词 Nonlinear poroelasticity model Multiphysics finite element method Back-ward Euler method
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Analysis of a Laplace Spectral Method for Time-Fractional Advection-Diffusion Equations Incorporating the Atangana-Baleanu Derivative
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作者 Kamran Farman Ali Shah +3 位作者 Kallekh Afef J.F.Gómez-Aguilar Salma Aljawi Ioan-Lucian Popa 《Computer Modeling in Engineering & Sciences》 2025年第6期3433-3462,共30页
In this article,we develop the Laplace transform(LT)based Chebyshev spectral collocation method(CSCM)to approximate the time fractional advection-diffusion equation,incorporating the Atangana-Baleanu Caputo(ABC)deriva... In this article,we develop the Laplace transform(LT)based Chebyshev spectral collocation method(CSCM)to approximate the time fractional advection-diffusion equation,incorporating the Atangana-Baleanu Caputo(ABC)derivative.The advection-diffusion equation,which governs the transport of mass,heat,or energy through combined advection and diffusion processes,is central to modeling physical systems with nonlocal behavior.Our numerical scheme employs the LT to transform the time-dependent time-fractional PDEs into a time-independent PDE in LT domain,eliminating the need for classical time-stepping methods that often suffer from stability constraints.For spatial discretization,we employ the CSCM,where the solution is approximated using Lagrange interpolation polynomial based on the Chebyshev collocation nodes,achieving exponential convergence that outperforms the algebraic convergence rates of finite difference and finite element methods.Finally,the solution is reverted to the time domain using contour integration technique.We also establish the existence and uniqueness of the solution for the proposed problem.The performance,efficiency,and accuracy of the proposed method are validated through various fractional advection-diffusion problems.The computed results demonstrate that the proposed method has less computational cost and is highly accurate. 展开更多
关键词 Laplace transform spectral method existence theory fractional derivative with non-singular kernel contour integration methods
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Applying the Radial Basis Function Method to Estimate the Distribution of Total Suspended Matter Concentration in Hangzhou Bay
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作者 CHEN Wanqian GAO Jinpeng +5 位作者 XU Minjie LIU Zezheng LI Bingtian LV Jing LI Shujiang SUN Junchuan 《Journal of Ocean University of China》 2025年第3期557-568,共12页
Ocean remote sensing satellites provide observations with high spatiotemporal resolution.However,the influence of clouds,fog,and haze frequently leads to significant data gaps.Accurate and effective estimation of thes... Ocean remote sensing satellites provide observations with high spatiotemporal resolution.However,the influence of clouds,fog,and haze frequently leads to significant data gaps.Accurate and effective estimation of these missing data is highly valuable for engineering and scientific research.In this study,the radial basis function(RBF)method is used to estimate the spatial distribution of total suspended matter(TSM)concentration in Hangzhou Bay using remote sensing data with severe data gaps.The estimation precision is validated by comparing the results with those of other commonly used interpolation methods,such as the Kriging method and the basic spline(B-spline)method.In addition,the applicability of the RBF method is explored.Results show that the estimation of the RBF method is significantly close to the observation in Hangzhou Bay.The average of the mean absolute error,mean relative error,and root mean square error in all the experiments is evidently smaller than those of the Kriging and B-spline interpolations,indicating that the proposed method is more appropriate for estimating the spatial distribution of the TSM in Hangzhou Bay.Finally,the TSM distribution in the blank observational area is predicted.This study can provide some reference values for handling watercolor remote sensing data. 展开更多
关键词 ocean remote sensing satellite total suspended matter concentration INTERPOLATION radial basis function Kriging method basic spline method
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