检索结果-南通市图书馆

Numerical Simulation of Radiation Transport to Improve Microalgae Cultivation in an Air-Lift Photobioreactor

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Thermal Science 2025年第1期34卷 62-76页

作者： zhang Xianbin LI mingjia HUNG Tzuchen zhang Zixun Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education School of Energy and Power EngineeringXi'an Jiaotong University School of Mechanical Engineering Beijing Institute of Technology Department of Mechanical Engineering Taipei University of Technology

A comprehensive numerical model is developed to simulate the growth of microalgae under light/dark cycling *** purpose of this study is to predict the growth rate of Chlorella vulgaris cultivated in photobioreactors(PBRs) in order to improve the light conditions for microalgae and enhance the photosynthetic *** fluid dynamics(CFD) is used to simulate its internal hydrodynamic *** Lagrangian method is employed to track the movement of microalgae *** radiative transfer equation(RTE)is used to obtain light intensity *** combination of light radiation field and microalgae cell motions is used to construct the light history and they are integrated into the model of the photosynthetic units(PSU) to calculate the microalgae growth *** numerical results demonstrate that enhanced light/dark cycling frequency with ordered mixing can promote efficient microalgae *** effect of the vortex flow field generated by the baffles in an air-lift PBR is analyzed for increasing microalgae growth *** using the 1:1 baffle spacing,the biomass production of microalgae is increased by 41.8% compared to the original PBR.

关键词： light distribution particle tracking photobioreactor structure optimization

Melting Evaluation of Phase Change Materials Impregnated into Cascaded Metal Foams with Regionalized Enhancement

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Thermal Science 2025年第1期34卷 223-241页

作者： WEI Xinyi zhang Nan zhang Zhaoli CAO Xiaoling YUAN Yanping School of Mechanical Engineering Southwest Jiaotong University

Metal foam promotes the heat transfer of phase change materials(PCMs) in the penalty of reducing the energy storage density of the composite *** this work,the effects of constant porosity(0.96,0.94,0.92,or 0.90) and pore density(PPI) of metal foam on heat transfer of composite PCMs are *** rate could be enhanced by employing with low porosity copper ***,aiming to the right bottom phase changing "dead region",a regionalized enhancement strategy of cascaded metal foams is *** dynamic melting performances of all the composite PCMs are comprehensively *** results reveal that the cascaded configuration is beneficial for *** show that the horizontal strategy enhances melting performance:a maximum of 17.98% reduction in total melting time could be reached when the rear part porosity is 90%.The energy storage density rate could be raised by 5.48%.Besides,the vertical strategy performs with a better average temperature uniformity of 0.441 and brings a lower temperature in the heated *** sum up,the regionalized enhancement of copper foam provides better performance in the phase change *** shows significant potential for solar heat storage and thermal protection.

关键词： copper metal foam heat transfer enhancement phase change materials regionalized enhancement

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

丰都县陆生野生动物资源调查初报

西南师范大学学报（自然科学版） 2002年第6期27卷 955-960页

作者：王志坚蒋国福张运明岳兴建张昊星王军辉西南师范大学生命科学学院重庆400715

野外调查采用样带法、样方法、样线法和样点法,并结合访问进行.该次调查显示,丰都县有陆生野生脊椎动物18目(亚目)40科128种,其中,国家二级重点保护动物8种.结合历史记载,共有4纲25目(亚目)61科188种,并列出了名录.

关键词：丰都县陆生野生动物资源名录资源调查野生脊椎动物国家保护动物

维普期刊数据库

The optimal control theory——a scientific approach to fundamentally solving control problems

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2025年第1期68卷 389-391页

作者： Huanshui zhang School of Electrical and Automation Engineering Shandong University of Science and Technology School of Control Science and Engineering Shandong University

The maximum principle has bridged mathematical optimization to optimal control,ushering in significant developments and refinements in optimal control theory,notably during the 1960s with the advent of linear quadratic (LQ)control and linear quadratic estimation (LQE).This progression propelled optimal control theory into further advancements,encompassing stochastic control,robust/H-infinity control,model predictive control (MPC),networked control,and reinforcement learning *** control,established upon a rigorous mathematical foundation,extends static optimization theory to dynamic systems,exhibiting scientific essence,unity,and ***,since its inception,optimal control theory has served as an indispensable core role across all control-related domains,including communication-constrained control in networked systems,consensus control,cooperative control,and reinforcement learning control.

关键词：

同方期刊数据库

Method for Estimating the State of Health of Lithium-ion Batteries Based on Differential Thermal Voltammetry and Sparrow Search Algorithm-Elman Neural Network

在线全文

学校读者我要写书评

暂无评论

Energy Engineering 2025年第1期122卷 203-220页

作者： Yu zhang Daoyu zhang TiezhouWu School of Electrical and Electronic Engineering Hubei University of TechnologyWuhan430068China

Precisely estimating the state of health(SOH)of lithium-ion batteries is essential for battery management systems(BMS),as it plays a key role in ensuring the safe and reliable operation of battery ***,current SOH estimation methods often overlook the valuable temperature information that can effectively characterize battery aging during capacity ***,the Elman neural network,which is commonly employed for SOH estimation,exhibits several drawbacks,including slow training speed,a tendency to become trapped in local minima,and the initialization of weights and thresholds using pseudo-random numbers,leading to unstable model *** address these issues,this study addresses the challenge of precise and effective SOH detection by proposing a method for estimating the SOH of lithium-ion batteries based on differential thermal voltammetry(DTV)and an SSA-Elman neural ***,two health features(HFs)considering temperature factors and battery voltage are extracted fromthe differential thermal voltammetry curves and incremental capacity ***,the Sparrow Search Algorithm(SSA)is employed to optimize the initial weights and thresholds of the Elman neural network,forming the SSA-Elman neural network *** validate the performance,various neural networks,including the proposed SSA-Elman network,are tested using the Oxford battery aging *** experimental results demonstrate that the method developed in this study achieves superior accuracy and robustness,with a mean absolute error(MAE)of less than 0.9%and a rootmean square error(RMSE)below 1.4%.

关键词： Lithium-ion battery state of health differential thermal voltammetry Sparrow Search Algorithm

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

井下双位自锁式电磁铁参数优化及性能分析

磁性材料及器件 2017年第3期48卷 26-31页

作者：汪兴明张剑秋王强西南石油大学石油与天然气工程学院四川成都610500 中国船舶工业集团公司上海船厂船舶有限公司上海202164 中国航天科技集团公司烽火机械厂四川成都611130

针对井下的恶劣工作环境,为了降低电磁阀能耗,提出了一种利用永磁体自锁的电磁阀。为了提高电磁阀在工作过程中的性能,利用Ansoft Maxwell软件建立电磁铁的分析模型,并对模型进行有限元分析。分别考虑电磁铁衔铁在不同位置、永磁体不同... 详细信息

针对井下的恶劣工作环境,为了降低电磁阀能耗,提出了一种利用永磁体自锁的电磁阀。为了提高电磁阀在工作过程中的性能,利用Ansoft Maxwell软件建立电磁铁的分析模型,并对模型进行有限元分析。分别考虑电磁铁衔铁在不同位置、永磁体不同长度情况下,电磁铁的自锁性能和抗振动的能力。针对不同长度的线圈以及衔铁的不同位置,对电磁铁的换向能力进行有限元分析,得到合理的线圈长度。仿真结果分析表明,井下自锁式电磁铁增加永磁体的长度有助于衔铁抗振动能力的提高,但会削弱电磁铁的换向能力。综合考虑上述因素,结合电磁铁的实际尺寸,得到永磁体长度和线圈长度的优化设计参数分别为3mm和21mm。

关键词：油气井工程电磁铁有限元分析法双位自锁优化设计

维普期刊数据库

Automatic and Rapid Throughflow-Based Optimal Design Method for Multi-Stage Axial-Flow Compressors

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2025年第1期34卷 77-91页

作者： LEI Fan zhang Xiawen JU Yaping zhang Chuhua Department of Fluid Machinery and Engineering School of Energy and Power EngineeringXi'an Jiaotong University Production and Environmental Department China Huaneng Group.Co.Ltd. State Key Laboratory for Strength and Vibration of Mechanical Structures Xi'an Jiaotong University

Throughflow design has the advantages of less time consumption and large optimization space,and thus is the corner stone of advanced design system of multi-stage axial-flow *** majority of relevant studies were limited to the throughflow inverse designs,and quite few works have been till now devoted to the throughflow optimal *** this work,an automatic and rapid throughflow-based optimal design method is proposed for axial-flow compressors in which a throughflow inverse design solver is embedded in optimal genetic algorithm to improve the design efficiency of axial-flow *** types of design parameters in the throughflow inverse design of axial-flow compressors,i.e.,swirl and shroud curve,are simultaneously used to optimize both the blade shape and flow *** proposed method is validated by the redesign optimization of the benchmark axial-flow compressor NASA Stage 35,and the CFD predictions show that the throughflow-based optimization leads to 1.18% efficiency benefit at design *** proposed method is then utilized to the two-dimensional throughflow optimal design of a large-scale 6.5-stage axial-flow industrial *** optimal design results are confirmed by CFD predictions,indicating that the proposed method can effectively improve the design adiabatic efficiency of the compressors by 1.09% within a few minutes on desk-top *** throughflow design implications are also obtained for advanced axial-flow industrial *** work could enhance the capability of throughflow design method and has engineering application value to explore the throughflow optimization space of multi-stage axial-flow compressors.

关键词： NASA

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

倒数迭代算法的理论分析与方案探讨

计算机学报 1981年第5期 384-391页

作者：周兴铭张民选长沙工学院

本文阐述了倒数迭代算法的理论基础。对初始近似倒数表的构成及精度控制进行了理论分析,提出了一个既省器材又处理简单的硬件倒数表方案。文章提出了一个误差分析和精度控制的一般方法并用该方法分析了四种不同的迭代算法,指出了各种方... 详细信息

本文阐述了倒数迭代算法的理论基础。对初始近似倒数表的构成及精度控制进行了理论分析,提出了一个既省器材又处理简单的硬件倒数表方案。文章提出了一个误差分析和精度控制的一般方法并用该方法分析了四种不同的迭代算法,指出了各种方法的特点及适用范围。最后给出“近似倒数流水部件”设计一例,运用本文的理论分析,使硬件和流水线站数大为减少。

关键词：理论分析误差分析数值分析方案探讨迭代次数乘法器迭代算法精度控制截尾

侵蚀条件下坡地土壤水分与有效磷的空间分布特征

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

水土保持学报 2001年第2期15卷 41-44页

作者：李裕元邵明安张兴昌中国科学院水利部水土保持研究所陕西杨陵712100

坡地的水土流失及磷素在泥沙中的富集不仅导致土地生产力下降、环境恶化 ,也对下游水体的环境造成严重危害。以不同施磷时间的黄绵土为试验材料 ,通过人工模拟降雨试验观察了坡地侵蚀土壤水分含量 (SM)与有效磷含量 (APC)的空间变化特... 详细信息

坡地的水土流失及磷素在泥沙中的富集不仅导致土地生产力下降、环境恶化 ,也对下游水体的环境造成严重危害。以不同施磷时间的黄绵土为试验材料 ,通过人工模拟降雨试验观察了坡地侵蚀土壤水分含量 (SM)与有效磷含量 (APC)的空间变化特征。结果表明 :自坡顶向下侵蚀土壤表层 0～ 5 cm与 5～ 10 cm的土壤水分 (SM)呈现出完全一致的波浪状递增趋势。有效磷含量 (APC)的空间变化虽然也为波浪状 ,但其节奏要较水分变化快一倍 ,而且 0～ 5 cm与 5～ 10 cm两层间并不同步 ,下层略有滞后。磷向 2 0 cm以下土层的迁移量极少 ,不同坡位间差别不大。施磷 2 4d以前从坡顶向下有效磷含量 (APC)呈降低趋势 ,而施磷 2 4d以后在坡下则略有富集 ;施磷 6 d以前坡地 0～ 5 cm土层有效磷含量 (APC)较 6 d以后低

关键词：坡地土壤水分有效磷空间分布模拟降雨土壤侵蚀

维普期刊数据库