检索结果-南通市图书馆

具有时变状态约束的无人直升机抗饱和跟踪控制设计

在线全文

学校读者我要写书评

暂无评论

中南大学学报(自然科学版) 2025年第1期56卷 100-110页

作者：阎坤赵金泽高嵩曹凯万敏西安工业大学电子信息工程学院陕西西安710021 南京航空航天大学自动化学院江苏南京211106

针对无人直升机在飞行过程中面临的状态受限和执行器饱和等多约束问题,本研究结合时变障碍Lyapunov函数技术和辅助系统方法提出了一种抗饱和安全飞行控制策略。首先,对状态约束进行分析并建立了包含输入饱和的无人直升机非线性系统模型... 详细信息

针对无人直升机在飞行过程中面临的状态受限和执行器饱和等多约束问题,本研究结合时变障碍Lyapunov函数技术和辅助系统方法提出了一种抗饱和安全飞行控制策略。首先,对状态约束进行分析并建立了包含输入饱和的无人直升机非线性系统模型;其次,针对输入饱和问题,采用饱和误差构造辅助系统,并将辅助系统的输出变量反馈到控制器中以提高系统的抗饱和能力,同时针对状态约束问题,引入时变障碍Lyapunov函数对其进行处理,保证飞行状态在预设的安全约束范围内变化;最后,在反步控制技术的框架下,设计了同时存在时变状态约束和输入饱和的无人直升机跟踪飞行控制方案,并结合Lyapunov稳定性理论证明了整个闭环系统误差的有界稳定性。通过仿真验证并与传统PID控制方法相对比,验证了本文所提出控制算法的有效性和优越性。研究结果表明:所提出的控制算法不仅能够确保无人直升机的飞行状态在合理且安全的范围内变化,而且提高了整个飞控系统的抗饱和能力。

关键词：无人直升机状态约束执行器饱和辅助系统时变障碍Lyapunov函数

MOF-derived nitrogen-doped iron–nickel oxide carbon nanotubes as efficient oxygen electrocatalyst for long-life rechargeable zinc–air batteries

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2023年第10期42卷 3326-3336页

作者： tao zhao Yu-Hang Wu Zhi-Rong song Xue Wang Rui-Lian Yin Hui Xu Hui Cui xie-Hong cao Jun-Kuo gao School of Materials Science and Engineering Institute of Functional Porous MaterialsZhejiang Sci-Tech UniversityHangzhou310018China College of Materials Science and Engineering Pinghu Institute of Advanced MaterialsZhejiang University of TechnologyHangzhou310014China Institute of Optoelectronic Materials and Devices China Jiliang UniversityHangzhou310018China Physics Division Argonne National LaboratoryLemontIL60439USA Department of Chemistry and International Institute for Nanotechnology(IIN) Northwestern UniversityEvanstonIL60208USA

Electrocatalysts with high activities are crucial for highenergy-density Zn-air ***,the sluggish kinetics of oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)on the electrocatalysts hindered the development of Zn-air ***,a new class of MOF-derived nitrogen-doped carbon nanotubes encapsulated with bimetallic oxide(FeNiO@NCNT)through facile pyrolysis strategy is *** FeNiO@NCNT exhibits high catalytic activities for both OER and ORR.

关键词： nickel catalyst carbon

Effect of Incoming Vortex on Secondary Flows in Turbine Cascades with Planar and Non-Axisymmetric Endwall

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2024年第1期33卷 138-157页

作者： cao Zhiyuan WANG Chuxuan song Zhigao gao Xi zhao Wei LIU Bo School of Power and Energy Northwestern Polytechnical UniversityXi'an 710072China National Key Laboratory of Science and Technology on Aerodynamic Design and Research Northwestern Polytechnical UniversityXi'an 710072China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100080China School of Aeronautics and Astronautics University of Chinese Academy of SciencesBeijing 100080China

Non-Axisymmetric Endwall Profiling(NAEP) is commonly utilized in turbines to eliminate secondary ***,most of the NAEP methods consider a single-blade row environment without incorporating the effect of the stage *** paper aims to investigate the influence mechanism of the incoming vortex on the endwall secondary flow structures of NAEP in a highly loaded turbine *** model the incoming vortex in a stage environment,this study considers a half-delta wing as the vortex generator at the upstream of the turbine *** NAEP is then carried out for a highly loaded turbine cascade with an in-house numerical optimization design platform subject to no incoming *** simulation is also carried out under the influence of the incoming vortex for the turbine cascades with both planar and non-axisymmetric *** paper furthers investigated the pitchwise effect of the incoming vortex on the near endwall secondary *** results indicate that the NAEP effectively improves the endwall secondary flow of the turbine cascade,where the total pressure loss coefficient and the secondary kinetic energy(SKE) are reduced by 7.3%,and 45.7%,*** is further seen that with the incoming vortex,the NAEP achieves a considerable control effect on the endwall secondary flow of the turbine *** incoming vortex,the NAEP can still achieve considerable control effect on the endwall secondary flow of the turbine cascade;the averaged reductions of loss coefficient and SKE are 7.8% and 14.2%,*** some pitchwise locations,incoming vortex can suppress the convection of cross-passage flow toward the suction corner greatly and reduce the loss coefficient of the baseline *** incoming vortex at 4/7 pitch impinged right at the blade leading edge,leading to the generation of low-momentum fluid,which increased the size and the strength of the horseshoe *** all the pitchwise locations,NAEP can suppress the seco

关键词： non-axisymmetric endwall secondary flow incoming vortex passage vortex stage environment

高温环境下2.5D针刺C/SiC复合材料失效机理及多尺度失效分析方法研究

在线全文

学校读者我要写书评

暂无评论

陶瓷学报 2025年第1期46卷 139-149页

作者：陈亮孟琳书张音旋王广帅曹奇凯赵铭卓吴涛高希光宋迎东中国航空工业集团公司沈阳飞机设计研究所辽宁沈阳110035 大连理工大学辽宁大连116024 南京航空航天大学江苏南京210016 南京航空航天大学江苏省航空动力系统重点实验室江苏南京210016 南京航空航天大学机械结构力学及控制国家重点实验室江苏南京210016

针对2.5D针刺C/SiC复合材料的失效破坏进行了试验和仿真计算研究。开展了室温、500℃、1000℃无氧环境下0°层、网胎层材料的拉伸、压缩破坏试验以及2.5D针刺C/SiC复合材料的拉伸、压缩和弯曲破坏试验,并利用电子显微镜对试验件断口进... 详细信息

针对2.5D针刺C/SiC复合材料的失效破坏进行了试验和仿真计算研究。开展了室温、500℃、1000℃无氧环境下0°层、网胎层材料的拉伸、压缩破坏试验以及2.5D针刺C/SiC复合材料的拉伸、压缩和弯曲破坏试验,并利用电子显微镜对试验件断口进行观察,分析了2.5D针刺C/SiC复合材料在不同温度下的损伤模式和失效机理。基于试验数据与观察结果,建立了通过单一铺层性能参数获取宏观针刺元件力学性能的方法,并依据多尺度理论和渐进损伤方法,借助Abaqus子程序二次开发进行了针刺C/SiC复合材料强度仿真分析。仿真预测的应力分布、失效模式与试验结果吻合较好,采用最大应变准则的强度预测精度可达94.7%,验证了分析方法在室温与高温环境下的准确性。

关键词： C/SiC复合材料多尺度分析性能预测失效分析

Existence of Solutions to a p-Laplacian Equation with Integral Initial Condition

在线全文

学校读者我要写书评

暂无评论

Communications in Mathematical Research 2017年第4期33卷 304-310页

作者： song wen-JING cao CHUN-LING zhao ZHI-QIANG gao wen-jie Institute of Applied Mathematics Jilin University of Finance and Economics School of Mathematics Jilin University No.11 High School of Changchun

In this paper, a class of one-dimension p-Laplacian equation with nonlocal initial value is studied. The existence of solutions to such a problem is obtained by using the topological degree method.

关键词： integral initial condition existence topological

Elimination of cracks in stainless steel casings via 3D printed sand molds with an internal topology structure

在线全文

学校读者我要写书评

暂无评论

China Foundry 2024年第4期21卷 319-326页

作者： Jun-hang Xu Bao-zhi Li zhao-wei song Yun-bao gao Jing-ming Li Yu Wang Qiu-lin wen Heng cao Zeng-rui Wang National Key Laboratory of Advanced Casting Technologies Shenyang 110022China Shenyang Research Institute of Foundry Co. Ltd.CAMShenyang 110022China

The important supporting component in a gas turbine is the casing,which has the characteristics of large size,complex structure,and thin *** the context of existing 3DP sand casting processes,casting crack defects are prone to *** leads to an increase in the scrap rate of casings,causing significant resource ***,the presence of cracks poses a significant safety hazard after the casings are put into *** generation of different types of crack defects in stainless steel casings is closely related to casting stress and the high-temperature concession of the sand ***,the types and causes of cracks in stainless steel casing products,based on their structural characteristics,were systematically *** sand molds with different internal topology designs were printed using the 3DP technology to investigate the impact of sand mold structures on high-temperature *** optimal sand mold structure was used to cast casings,and the crack suppression effect was verified by analyzing its eddy current testing *** experimental results indicate that the skeleton structure has an excellent effect on suppressing cracks in the *** research holds important theoretical and engineering significance in improving the quality of casing castings and reducing production costs.

关键词： gas turbine casing crack defects 3D printed sand mold topological structure high-temperature concession

Telomere-to-telomere assembly of cassava genome reveals the evolution of cassava and divergence of allelic expression

在线全文

学校读者我要写书评

暂无评论

Horticulture Research 2023年第11期10卷 82-95页

作者： xin-Dong Xu Ru-Peng zhao Liang Xiao Liuying Lu Min gao Yu-Hong Luo Zu-wen Zhou Si-Ying Ye Yong-Qing Qian bing-Liang Fan Xiaohong Shang Pingli Shi wendan Zeng Sheng cao Zhengdan Wu Huabing Yan Ling-Ling Chen Jia-Ming song State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources College of Life Science and TechnologyGuangxi UniversityNanning 530004China Cash Crops Research Institute Guangxi Academy of Agricultural SciencesNanning 530007China

Cassava is a crucial crop that makes a significant contribution to ensuring human food ***,high-quality telomere-totelomere cassava genomes have not been available up to now,which has restricted the progress of haploid molecular breeding for *** this study,we constructed two nearly complete haploid resolved genomes and an integrated,telomere-to-telomere gap-free reference genome of an excellent cassava variety,‘xinxuan 048’,thereby providing a new high-quality genomic ***,the evolutionary history of several species within the Euphorbiaceae family was *** comparative analysis of haploid genomes,it was found that two haploid genomes had extensive differences in linear structure,transcriptome features,and epigenetic *** located within the highly divergent regions and differentially expressed alleles are enriched in the functions of auxin response and the starch synthesis *** high heterozygosity of cassava‘xinxuan 048’leads to rapid trait segregation in the first selfed *** study provides a theoretical basis and genomic resource for molecular breeding of cassava haploids.

关键词： breeding thereby evolution

Light weight, mechanically strong and biocompatible α-chitin aerogels from different aqueous alkali hydroxide/urea solutions

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

Science China Chemistry 2016年第11期59卷 1405-1414页

作者： Beibei Ding Dan zhao Jianhui song Huichang gao Duoduo Xu Min Xu Xiaodong cao Lina Zhang Jie Cai College of Chemistry & Molecular Sciences Wuhan University Key Laboratory of Rubber-Plastics Ministry of Education Shandong Provincial Key Laboratory of Rubber-PlasticsQingdao University of Science & Technology Department of Physics Shanghai Key Laboratory of Magnetic Resonance East China Normal University School of Materials Science and Engineering South China University of Technology

Light weight and mechanically strong α-chitin aerogels were fabricated using the sol-gel/self-assembly method from α-chitin in different aqueous alkali hydroxide(KOH, Na OH and Li OH)/urea solutions. All of the α-chitin solutions exhibited temperature-induced rapid gelation behavior. 13 C nuclear magnetic resonance(NMR) spectra revealed that the aqueous alkali hydroxide/urea solutions are non-derivatizing solvents for α-chitin. Fourier transform infrared(FT-IR), X-ray diffraction(XRD) and cross-polarization magic angle spinning(CP/MAS) 13 C NMR confirmed that α-chitin has a stable aggregate structure after undergoing dissolution and regeneration. Subsequently, nanostructured α-chitin aerogels were fabricated by regeneration from the chitin solutions in ethanol and then freeze-drying from t-Bu OH. These α-chitin aerogels exhibited high porosity(87% to 94%), low density(0.09 to 0.19 g/cm^3), high specific surface area(419 to 535 m^2/g) and large pore volume(2.7 to 3.8 cm^3/g). Moreover, the α-chitin aerogels exhibited good mechanical properties under compression and tension models. In vitro studies showed that m BMSCs cultured on chitin hydrogels have good biocompatibility. These nanostructured α-chitin aerogels may be useful for various applications, such as catalyst supports, carbon aerogel precursors and biomedical materials.

关键词： chitin aerogels alkali hydroxide/urea aqueous solutions mechanical properties biocompatibility

Observation of coupling between zero- and two- dimensional semiconductor systems based on anomalous diamagnetic effects

在线全文

学校读者我要写书评

暂无评论

Nano Research 2016年第2期9卷 306-316页

作者： Shuo cao Jing Tang Yue Sun Kai Peng Yunan gao Yanhui zhao Chenjiang Qian Sibai Sun Hassan Ali Yuting shao Shiyao Wu Feilong song David A. Williams Weidong Sheng Kuijuan Jin Xiulai Xu Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China Hitachi Cambridge Laboratory Cavendish Laboratory Cambridge CB3 OHE UK Department of Physics Fudan University Shanghai 200433 China Collaborative Innovation Center of Quantum Matter Beijing 100084 China

We report the direct observation of coupling between a single self-assembled InAs quantum dot and a wetting layer, based on strong diamagnetic shifts of many-body exciton states using magneto-photoluminescence spectroscopy. An extremely large positive diamagnetic coefficient is observed when an electron in the wetting layer combines with a hole in the quantum dot; the coefficient is nearly one order of magnitude larger than that of the exciton states confined in the quantum dots. Recombination of electrons with holes in a quantum dot of the coupled system leads to an unusual negative diamagnetic effect, which is five times stronger than that in a pure quantum dot system. This effect can be attributed to the expansion of the wavefunction of remaining electrons in the wetting layer or the spread of electrons in the excited states of the quantum dot to the wetting layer after recombination. In this case, the wavefunction extent of the final states in the quantum dot plane is much larger than that of the initial states because of the absence of holes in the quantum dot to attract electrons. The properties of emitted photons that depend on the large electron wavefunction extents in the wetting layer indicate that the coupling occurs between systems of different dimensionality, which is also verified from the results obtained by applying a magnetic field in different configurations. This study paves a new way to observe hybrid states with zero- and two-dimensional structures, which could be useful for investigating the Kondo physics and implementing spin-based solid-state quantum information processing.

关键词： magneto-photoluminescence InAs quantum dots wetting layer strong diamagnetic effects