检索结果-南通市图书馆

计及需求侧柔性负荷调控的综合能源系统优化运行方法研究

在线全文

学校读者我要写书评

暂无评论

暖通空调 2024年第8期54卷 81-89页

作者：席昌远吴迪李桂强韩中合张玉龙赵旭东华北电力大学保定华北电力大学河北省低碳高效发电技术重点实验室保定中国科学技术大学合肥河北省建筑科学研究院有限公司石家庄赫尔大学可持续能源技术研究中心英国赫尔

引入柔性电热负荷参与到综合能源系统的调度中,综合考虑源荷两侧,供能侧构建了由光伏机组、能量转化装置和储能系统组成的多能源系统模型,需求侧构建了可平移、可转移和可削减柔性电负荷与耦合室内外温度的柔性热负荷模型。以系统日运... 详细信息

引入柔性电热负荷参与到综合能源系统的调度中,综合考虑源荷两侧,供能侧构建了由光伏机组、能量转化装置和储能系统组成的多能源系统模型,需求侧构建了可平移、可转移和可削减柔性电负荷与耦合室内外温度的柔性热负荷模型。以系统日运行成本最低为优化目标,分别对供能侧与需求侧设备出力和柔性负荷的用能时间与负荷大小进行了优化。对北京市某社区综合能源系统的优化调度进行了研究。结果表明:柔性负荷参与调度能够降低负荷波动,热负荷峰值由原来的3876.80 kW下降到3822.11 kW,减少了54.69 kW;电负荷的峰谷差从1488.81 kW下降到1382.69 kW,波动率下降了7.1%;源荷两侧共同参与优化调度能够提高系统经济效益,系统成本比原来降低了2.26%。

关键词：柔性负荷综合能源系统源荷两侧优化调度电负荷热负荷

Analysis on the Resilience of Key Pre-distribution in Sensor Networks

在线全文

学校读者我要写书评

暂无评论

China Communications 2007年第3期4卷 30-37页

作者： Shen yulong Ma Jianfeng Pei Qingqi xidian Univ Sch Comp Sci & Technol Xian 710071 Shaanxi Peoples R China Minist Educ Key Lab Comp Networks & Informat Secur Xian 710071 Shaanxi Peoples R China

Resilience against node capture is one of the main indicators of the key pre-distribution security in sensor *** providing the attack model and the definition of the resilience against node capture of sensor networks,the resilience of basic random key pre-distribution,Q-composite random key pre-distribution and their reinforced schemes are analyzed and compared in *** results show that the size of key pool,the numbers of the keys stored in nodes and the value of Q determine the resilience of random key *** tradeoff between the resilience,security connectivity and costs in sensor networks is *** researches lay a foundation on the design of the secure protocol and the algorithm in the specific application environment of sensor networks.

关键词： sensor networks resilience analysis key pre-distribution

Biaxial tensile behavior of Ti-6Al-4V under proportional loading

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第5期36卷 344-362页

作者： Lin QI Yazhou gUO Kanghua JIN Huaipu KANg yulong LI School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of Impact Dynamics and Engineering Applications Northwestern Polytechnical UniversityXi’an 710072China School of Civil Aviation Northwestern Polytechnical UniversitySuzhou 215699China NPU Yangzi River Delta Research Institute Suzhou 215400China

The biaxial tensile behavior of isotropic Ti-6Al-4 V is characterized in this paper.A novel cruciform specimen was designed and optimized to achieve uniform stress and strain distribution within the gauge *** tensile tests were conducted at three different loading ratios by the biaxial testing *** Digital Image Correlation(DIC)technique was applied to determine strain distribution,and a high-speed camera was employed to record the fracture *** Inverse Analysis(IA)approach with a combined experimental and numerical method was proposed to determine the true stresses at the gauge section of the specimen during biaxial tensile *** results indicate that the initial yield locus can be described by the Cazacu criterion accurately,whereas the Mises criterion can predict better the strengthening behavior of Ti-6Al-4 V in the first quadrant in the principal stress space.

关键词： Biaxial tensile testing Inverse analysis Strengthening behavior Ti-6Al-4V Yield locus

基于感知自编码器的军品电路表面缺陷检测方法

在线全文

学校读者我要写书评

暂无评论

微电子学与计算机 2024年第4期41卷 47-54页

作者：郭帅兵胡玉龙柴波西安微电子技术研究所陕西西安710054

面向军品电路的表面缺陷检测任务,由于军品电路存在多品种、小批量,表面复杂的特点,现有方法对图像重建效果较差,本研究提出一种基于感知自编码器(Perceptual AutoEncoder,PAE)的方法,将感知损失与自注意力模块引入无监督方法,增加方法... 详细信息

面向军品电路的表面缺陷检测任务,由于军品电路存在多品种、小批量,表面复杂的特点,现有方法对图像重建效果较差,本研究提出一种基于感知自编码器(Perceptual AutoEncoder,PAE)的方法,将感知损失与自注意力模块引入无监督方法,增加方法的可迁移性与图像重建效果。与传统检测方法相比,基于感知自编码器的方法无需面临传统模板法的对齐、光照平衡、色彩平衡等问题,极大地提升了针对不同产品的可迁移性,可有效解决军品电路多品种、小批量检测面临的困难。具体方法为:使用特征金字塔与卷积方法提取不同尺度的特征向量并聚类,聚类后使用自注意力模块自动加权并增强需要关注的特征,而后重建图像,将该图像作为模板与输入进行差分比较。针对感知自编码器,在自制的数据集上进行了评估,评估结果表明,引入感知损失后的自编码器能够更准确地进行缺陷检测。

关键词：表面缺陷检测感知损失自编码器

Dynamic Biaxial Compression of CFRP Laminates Using Electromagnetic Loading

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2022年第5期35卷 891-900页

作者： Huaipu Kang Jintao Liang Yi Li Hao Cui yulong Li NPU Yangtze River Delta Research Institute Suzhou215400China School of Aeronautics Northwestern Polytechnical UniversityXi’an710072China School of Civil Aviation Northwestern Polytechnical UniversitySuzhou215400China

The dynamic biaxial compression test for carbon-fiber-reinforced polymer(CFRP)laminates was carried out via synchronous electromagnetic loading in this *** the experiments,four stress pulses transmitted along four incident bars,loading the square specimen simultaneously from four directions to keep the center of the specimen *** dynamic mechanical behavior of CFRP was obtained employing the one-dimensional wave propagation theory,and the deformation and failure processes of the specimens were recorded by a high-speed *** effects of various biaxial stresses on the compressive strength were investigated in three biaxial and one uniaxial loading *** the CFRP laminates,the dynamic transverse compressive stress showed little effect on the longitudinal ultimate compressive *** simulations were performed to understand the dynamic stress wave *** showed that the employed loading device could guarantee good biaxial loading conditions until the ultimate failure of the *** approach allows for the dynamic biaxial compression testing of various materials,which is of great significance in evaluating the dynamic impact performance of aeronautical composites.

关键词： Carbon-fiber-reinforced polymer(CFRP) Dynamic loading Biaxial testing Electromagnetic loading

A thermo-viscoelastic model for particle-reinforced composites based on micromechanical modeling

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

Acta Mechanica Sinica 2021年第3期37卷 402-413,I0001页

作者： Yang Chen xiaohao Shi Zhenqiang Zhao Zaoyang guo yulong Li School of Civil Aviation Northwestern Polytechnical UniversityXi’an 710072China Institute of Biomedical Engineering and Health Sciences Changzhou UniversityChangzhou 213164China School of Science Harbin Institute of TechnologyShenzhen 518055China

Micromechanics-based constitutive models offer superior ability to estimate the effective mechanical properties for the composites,which greatly promote the computational efficiency in the multiscale analysis for composite *** this work,a thermo-viscoelastic model for particle-reinforced composites is proposed to estimate their thermal-mechanical coupling behaviors in terms of a micromechanics-based homogenization method in the time *** matrix and particles of the composites are modeled as“thermo-rheologically complex”viscoelastic *** temperature-dependent effective elastic strain energy ratios of particle to composite are proposed to evaluate the contributions of the matrix and *** thermo-viscoelastic model for the composites is then formulated by superposing the matrix and particle’s *** element simulations based on the representative volume element models are employed to validate the constitutive model under various thermal-mechanical coupling *** effects of the loading rate,viscous parameter and particle content on the effective thermal-mechanical responses of the composites are also comprehensively *** experimental data from literature are also employed to verify the constitutive *** findings show that the proposed thermo-viscoelastic model can accurately predict the thermal-mechanical coupling behaviors for the particle-reinforced composites.

关键词： Particle-reinforced composites Thermo-viscoelastic model Thermal-mechanical coupling Homogenization method Numerical validation

Highly efficient computation method for hazard quantification of uncontained rotor failure

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

Chinese Journal of Aeronautics 2020年第7期33卷 1980-1990页

作者： Zhenqiang ZHAO Peng LIU Yan LIU Chao ZHANg yulong LI Department of Aeronautical Structure Engineering Northwestern Poly technical UniversityXi'an 710072China Shaanxi Key Laboratory of Impact Dynamics and its Engineering Applications Northwestern Polytechnical UniversityXi’an 710072China

Uncontained Engine Rotor Failure(UERF)can cause a catastrophic failure of an aircraft,and the quantitative assessment of the hazards related to UERF is a very important part of safety ***,the procedure for hazard quantification of UERF recommended by the Federal Aviation Administration in advisory circular AC20-128A is cumbersome,as it involves building auxiliary lines and curve *** improve the efficiency and general applicability of the risk angle calculation,a boundary discretization method is developed that involves discretizing the geometry of the target part/structure into node points and calculating the risk angles numerically by iterating a particular algorithm over each node *** improved efficiency and excellent accuracy for the developed algorithm was validated through a comparison with manual solutions for the hazard quantification of the engine nacelle structures of a passenger aircraft using the guidance in *** further demonstrate the applicability of the boundary discretization method,the proposed algorithm was used to examine the influence of the target size and the distance between the target and rotor on the hazard probability.

关键词： Boundary discretization Critical point Hazard probability Risk angle Uncontained engine rotor failure

固体氧化物燃料电池和分部加热式S-CO_(2)循环联合发电系统设计与分析

在线全文

学校读者我要写书评

暂无评论

中国电机工程学报 2024年第19期44卷 7706-7716,I0018页

作者：马悦王哲曹梦龙姜悦茂纪玉龙韩凤翚大连海事大学轮机工程学院辽宁省大连市116000 叶轮机械研究所(西安交通大学能源与动力工程学院) 陕西省西安市710049

固体氧化物燃料电池(solid oxide fuel cell,SOFC)与余热回收相结合可进一步提高系统能量转换效率。该文设计一种SOFC与分部加热式超临界二氧化碳(partial heating supercritical CO_(2)Brayton cycle,PHSCBC)动力循环集成系统,SOFC系... 详细信息

固体氧化物燃料电池(solid oxide fuel cell,SOFC)与余热回收相结合可进一步提高系统能量转换效率。该文设计一种SOFC与分部加热式超临界二氧化碳(partial heating supercritical CO_(2)Brayton cycle,PHSCBC)动力循环集成系统,SOFC系统的出口废气作为高温热源,驱动PHSCBC进行联合发电。建立系统的电化学模型和热力学模型,对系统的能量和(火用)进行综合评价,并通过参数分析,研究汽碳比、燃料流量、压缩机进口温度和压力以及夹点温差对联合发电系统性能的影响。对系统性能进行优化,发现当系统燃料流量为0.54 mol/s、空气流量为6.19 mol/s,可达到净发电功率、发电效率、(火用)效率分别为260.08 kW、61.20%、56.54%,其中提高燃料流量将显著提高系统发电效率。所提出的混合系统具有高效、低成本和清洁的发电和供热性能,是一种具有实际应用前景的先进能量转换技术。

关键词：固体氧化物燃料电池分部加热式S-CO_(2)动力循环联合发电余热回收性能优化

维普期刊数据库博看期刊

Mechanical behaviors of polycrystalline NiTi SMAs of various grain sizes under impact loading

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2021年第7期64卷 1401-1411页

作者： xiAO Rui HOU Bing SUN QingPing ZHAO Han LI yulong School of Aeronautics Northwestern Polytechnical UniversityXi’an710072China Departement of Mechanical and Aerospace Engineering the Hong Kong University of Science and TechnologyHong Kong999077China Laboratoire de Mécanique et Technologie Cachan cedex94235France Sorbonne Université Paris75272France

This work presents mechanical properties of the NiTi polycrystalline superelastic shape memory alloys(SMA) of 5 different grain sizes under high-speed impacts. The amorphous, nanocrystalline(40, 80, 120 nm) and coarse grain(20 μm) sheets are manufactured with cold rolling and suitable heat treatments. A Hopkinson tensile bar is used to perform tests up to 45 m/s. Highspeed camera system and digital image correlation method are used to get the strain field and particle velocity field at a sampling frequency of 2×10~6 frames/s with a resolution of 924×768 pixels. Nominal stress-strain curves are obtained for all the sheets with a strain rate of about 1000 s~(-1) and they have a similar evolution to the quasi-static case but with much higher stress levels. The rate sensitivity is increased with the grain size and the stress level can reach up to a 70% growth for a coarse grain sheet but be totally insensitive for the amorphous sheet in the strain rate from 10~(-4) to 10~3 s~(-1). A single transformation front can be found under high-speed impact(45 m/s) at the early loading stage. The speed of the transformation front is calculated from strain time histories and the highest front speed of 811 m/s is observed which is never observed before. It also reveals that the front speed depends also on the grain size. With the same loading speed, the bigger the grain size is, the slower the transformation front speed is.

关键词： NiTi shape memory alloys mechanical property rate sensitivity phase transformation grain size effects