检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

VMD方法在旋转机械振动信号处理中的研究

计算机与数字工程 2022年第9期50卷 2093-2096页

作者：骆东松张树涛兰州理工大学电气工程与信息工程学院兰州730050

针对工作在环境复杂的旋转机械,提取的机械振动信号存在很强的噪音,系统信号和干扰噪声在频带上互相混叠,采用传统的降噪方法存在较大局限性。因此,论文提出基于变分模态分解(VMD)的故障诊断方法来消除噪音。针对VMD方法从原理上提出参... 详细信息

针对工作在环境复杂的旋转机械,提取的机械振动信号存在很强的噪音,系统信号和干扰噪声在频带上互相混叠,采用传统的降噪方法存在较大局限性。因此,论文提出基于变分模态分解(VMD)的故障诊断方法来消除噪音。针对VMD方法从原理上提出参数K、α、τ的确定方法,从而降低传统去噪的工作量,提高效率和可靠性等优势。

关键词：振动信号故障特征降噪变分模态分解

基于粒子群-差分进化耦合算法的滑带土强度三维数值反演分析

在线全文

学校读者我要写书评

暂无评论

土工基础 2022年第2期36卷 214-218页

作者：张述涛彭君民航中南机场设计研究院(广州)有限公司广州510405

滑动带作为滑坡的重要组成部分,是滑坡形成、发育和演化的关键,滑带土强度参数的确定对于滑坡稳定性分析具有重要意义。由于滑带土分布和参数的离散性、取样扰动影响和试验的误差,难以获得准确的参数值,对于体型复杂的滑坡,以调研得到... 详细信息

滑动带作为滑坡的重要组成部分,是滑坡形成、发育和演化的关键,滑带土强度参数的确定对于滑坡稳定性分析具有重要意义。由于滑带土分布和参数的离散性、取样扰动影响和试验的误差,难以获得准确的参数值,对于体型复杂的滑坡,以调研得到的稳定性状态进行三维数值参数反演分析是确定滑带土强度的较好方法。然而,采用试算法的反演方法存在三维数值分析工作量大的问题。以云南腾冲机场滑坡为例,依据实际的地形建立了精细化的三维数值模型,采用粒子群-差分进化法对滑坡当前状态滑带土强度进行参数反演,得出了滑带土饱和参数组合。采用该方法大大提高了滑坡参数反演分析的计算效率。

关键词：参数反演滑坡滑带土粒子群算法

基于Tau理论的机器人抓取运动仿生轨迹规划

在线全文

学校读者我要写书评

暂无评论

机械工程学报 2014年第13期50卷 42-51页

作者：张书涛张震钱晋武上海大学机电工程与自动化学院上海200072

针对机器人在抓取目标前的接近运动,提出一种基于Tau理论的仿生轨迹规划方法。Tau理论是认知科学研究者通过试验研究总结出的人和动物在接近和抓取物体时的运动策略。在Tau理论的基础上,对Tau理论的两种基本运动策略(Tau耦合策略和内部T... 详细信息

针对机器人在抓取目标前的接近运动,提出一种基于Tau理论的仿生轨迹规划方法。Tau理论是认知科学研究者通过试验研究总结出的人和动物在接近和抓取物体时的运动策略。在Tau理论的基础上,对Tau理论的两种基本运动策略(Tau耦合策略和内部Tau-g引导策略)进行运动学分析。针对内部Tau-g引导策略初始加速度不为零的问题,提出内部jerk引导的策略(内部Tau-j引导策略),并推导出基于Tau理论的机器人接近运动的轨迹规划公式。以三自由度平面机器人为例,进行轨迹规划、运动学分析、动力学分析、仿真和试验。结果表明,运用Tau理论进行轨迹规划,机器人手部的位置和姿态可在确定的时间同时到达目标,关节速度曲线、加速度曲线和驱动力矩曲线光滑连续,笛卡儿空间的轨迹是具有'钟形'光滑连续速度曲线的直线,验证了方法的有效性。

关键词： Tau理论仿生机器人轨迹规划

N-doped graphene quantum dot-decorated N-TiO2/P-doped porous hollow g-C_(3)N_(4) nanotube composite photocatalysts for antibiotic photodegradation and H2 production

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 165-178页

作者： Jingshu Yuan Yao zhang Xiaoyan zhang Junjie zhang Shen’gen zhang Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China Xi’an Fanyi University Xi’an 710105China Shunde Graduate School of University of Science and Technology Beijing Foshan 528399China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao SAR 820000China

Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the two primary drawbacks of pure TiO_(2). We combined N-doped graphene quantum dots (N-GQDs), morphology regulation, and heterojunction construction strategies to synthesize N-GQD/N-doped TiO_(2)/P-doped porous hollow g-C_(3)N_(4) nanotube (PCN) composite photocatalysts (denoted as G-TPCN). The optimal sample (G-TPCN doped with 0.1wt% N-GQD, denoted as 0.1% G-TPCN) exhibits significantly enhanced photoabsorption, which is attributed to the change in bandgap caused by elemental doping (P and N), the improved light-harvesting resulting from the tube structure, and the upconversion effect of N-GQDs. In addition, the internal charge separation and transfer capability of0.1% G-TPCN are dramatically boosted, and its carrier concentration is 3.7, 2.3, and 1.9 times that of N-TiO_(2), PCN, and N-TiO_(2)/PCN(TPCN-1), respectively. This phenomenon is attributed to the formation of Z-scheme heterojunction between N-TiO_(2) and PCNs, the excellent electron conduction ability of N-GQDs, and the short transfer distance caused by the porous nanotube structure. Compared with those of N-TiO_(2), PCNs, and TPCN-1, the H2 production activity of 0.1%G-TPCN under visible light is enhanced by 12.4, 2.3, and 1.4times, respectively, and its ciprofloxacin (CIP) degradation rate is increased by 7.9, 5.7, and 2.9 times, respectively. The optimized performance benefits from excellent photoresponsiveness and improved carrier separation and migration efficiencies. Finally, the photocatalytic mechanism of 0.1% G-TPCN and five possible degradation pathways of CIP are proposed. This study clarifies the mechanism of multiple modification strategies to synergistically improve the photocatalytic performance of 0.1% G-TPCN and provides a potential strategy for rationally designing novel photocatalysts for environmental remediation and solar energy conversion.

关键词： N-doped TiO_(2) N-doped graphene quantum dots P-doped g-C_(3)N_(4) porous hollow nanotube heterojunction photocatalysis

政府绩效评估的嵌入治理与偏差控制:一个结构-关系的分析框架

在线全文

学校读者我要写书评

暂无评论

河南师范大学学报（哲学社会科学版） 2021年第3期48卷 48-54页

作者：张书涛河南师范大学公共政策与社会管理创新研究中心河南新乡453007

压力型体制下上级政府主要凭借科层制正式权力结构运用“命令-控制”机制,自上而下地推进评估政策的执行,而下级政府则采取自下而上的“自主-应对”方式进行非正式策略回应。“结构-关系”框架为政府绩效评估嵌入治理的有效运作提供了... 详细信息

压力型体制下上级政府主要凭借科层制正式权力结构运用“命令-控制”机制,自上而下地推进评估政策的执行,而下级政府则采取自下而上的“自主-应对”方式进行非正式策略回应。“结构-关系”框架为政府绩效评估嵌入治理的有效运作提供了治理基础和效能保障。面对上下级政府之间的关系扭曲、行为失范、参与排斥和合法性缺失等治理偏差问题,需要在厘清诸治理要素及其逻辑关系的基础上构建具有一致性和协同性的政府绩效评估制度系统。通过政府规制对政府绩效评估的政策执行进行整体化控制,通过政策规范对政府绩效评估自主性行为进行限制,同时,确立政府绩效评估的价值目标与合作导向,实现政府、社会与公众的多层次治理协同。

关键词：政府绩效评估嵌入治理偏差控制制度协同

Reversing free-electron transfer of sulfide cocatalyst for exceptional photocatalytic H_(2)evolution

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2024年第4期171卷 147-149页

作者： Yanfeng zhang Zhenyi zhang National Experimental Chemistry Teaching Center Hebei Key Laboratory of Inorganic Nano-materialsCollege of Chemistry and Materials ScienceHebei Normal UniversityShijiazhuang 050024China Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission Key Laboratory of Photosensitive Materials and Devices of Liaoning ProvinceSchool of Physics and Materials EngineeringDalian Minzu UniversityDalian 116600China

Recently,Yu and co-workers deeply explore the potential impact of free electron transfer between co-catalysts and photocatalyst carriers on H_(2)evolution efficiency of active sites over MoS_(2+x).They pro-pose an electron-reversal tactics to evade the unexpected electron transfer and synchronously regulate the above transfer in a beneficial orientation for weakening hydrogen adsorption on S ***,this highlight not only discusses and summarizes the essences of electron reversal and the optimized H ad-sorption/desorption mechanism,but also emphasizes the significance of femtosecond transient absorp-tion spectroscopy(fs-TAS)and in-situ irradiated X-ray photoelectron spectroscopy(ISI-XPS)for revealing charge transfer dynamics and *** anticipate that this highlight can disseminate a new per-spective on the roles of photocatalyst carriers in improving cocatalytic H_(2)-production kinetics.

关键词： Photocatalysis Cocatalyst Electron reversal Antibonding-orbital occupancy S–H bonds

Deep Guided Attention Network for Joint Denoising and Demosaicing in Real Image

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 Electronics 2024年第1期33卷 303-312页

作者： Tao zhang Ying FU Jun zhang School of Computer Science and Technology Beijing Institute of Technology Advanced Reasearch Institute of Multidisciplinary Science Beijing Institute of Technology

Denoising(DN) and demosaicing(DM) are the first crucial stages in the image signal processing pipeline. Recently, researches pay more attention to solve DN and DM in a joint manner, which is an extremely undetermined inverse problem. Existing deep learning methods learn the desired prior on synthetic dataset, which limits the generalization of learned network to the real world data. Moreover, existing methods mainly focus on the raw data property of high green information sampling rate for DM, but occasionally exploit the high intensity and signalto-noise(SNR) of green channel. In this work, a deep guided attention network(DGAN) is presented for real image joint DN and DM(JDD), which considers both high SNR and high sampling rate of green information for DN and DM, respectively. To ease the training and fully exploit the data property of green channel, we first train DN and DM sub-networks sequentially and then learn them jointly, which can alleviate the error accumulation. Besides, in order to support the real image JDD, we collect paired raw clean RGB and noisy mosaic images to conduct a realistic dataset. The experimental results on real JDD dataset show the presented approach performs better than the state-of-the-art methods, in terms of both quantitative metrics and qualitative visualization.

关键词： Training Visualization Inverse problems Green products Noise reduction Pipelines Signal processing

Value Iteration-Based Cooperative Adaptive Optimal Control for Multi-Player Differential Games With Incomplete Information

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 690-697页

作者： Yun zhang Lulu zhang Yunze Cai the Department of Automation Shanghai Jiao Tong UniversityShanghai 200240 the Key Laboratory of System Control and Information Processing Ministry of Education of ChinaShanghai 200240China

This paper presents a novel cooperative value iteration(VI)-based adaptive dynamic programming method for multi-player differential game models with a convergence *** players are divided into two groups in the learning process and adapt their policies *** method removes the dependence of admissible initial policies,which is one of the main drawbacks of the PI-based ***,this algorithm enables the players to adapt their control policies without full knowledge of others’ system parameters or control *** efficacy of our method is illustrated by three examples.

关键词： Adaptive dynamic programming incomplete information multi-player differential game value iteration

Host plant traits play a crucial role in shaping the composition of epiphytic microbiota in the arid desert,Northwest China

在线全文

学校读者我要写书评

暂无评论

Journal of Arid Land 2024年第5期16卷 699-724页

作者： zhang Jun zhang Yuanming zhang Qi State Key Laboratory of Desert and Oasis Ecology Key Laboratory of Ecological Safety and Sustainable Development in Arid LandsXinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China Xinjiang Key Laboratory of Biodiversity Conservation and Application in Arid Lands Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China Xinjiang Field Scientific Observation Research Station of Tianshan Wild Fruit Forest Ecosystem Yili Botanical GardenXinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China College of Life Sciences Shihezi UniversityShihezi 832003China

Phyllosphere microorganisms are a crucial component of environmental microorganisms,highly influenced by host characteristics,and play a significant role in plant health and ***,the impact of host characteristics on shaping phyllosphere microbial communities of plants with different life forms remains *** high-throughput sequencing technology,this study analyzed the diversity and community composition of phyllosphere epiphytic microorganisms(e.g.,bacteria and fungi)of various plant life forms in the hinterland of the Gurbantunggut Desert,Northwest *** annotation of prokaryotic taxa(FAPROTAX)and fungi function guild(FUNGuild)were employed to assess the ecological functions of microorganisms and to investigate the role of stochastic and deterministic processes in shaping phyllosphere microbial *** showed a diverse array of phyllosphere epiphytic microorganisms in the desert plants,with Proteobacteria,Cyanobacteria,and Actinobacteriota dominating bacterial community,while Ascomycota and Basidiomycota were prevalent in fungal *** across different plant life forms highlighted distinct microbial communities,indicating strong filtering effects by plant *** prediction identified intracellular parasites(accounting for 27.44%of bacterial community abundance),chemoheterotrophy(10.12%),and phototrophy(17.41%)as the main functions of epiphytic bacteria on leaves of different life form *** prediction indicated that phyllosphere epiphytic fungi primarily served as Saprotrophs(81.77%),Pathotrophs(17.41%),and Symbiotrophs(0.82%).Co-occurrence network analysis demonstrated a predominance of positive correlations among different microbial ***-Crick dissimilarity index analysis revealed that deterministic processes predominantly influenced phyllosphere bacterial and fungal community *** partitioning analysis and random forest modeling suggested that pla

关键词： phyllosphere epiphytic bacteria phyllosphere epiphytic fungi community structure community diversity functional diversity plant life form plant functional traits