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感应读出延时线阳极光子计数探测器研究

光谱学与光谱分析 2024年第5期44卷 1291-1296页

作者：张蕊利刘永安张亚龙杨向辉刘哲苏桐赵宝升盛立志中国科学院西安光学精密机械研究所瞬态光学与光子技术国家重点实验室陕西西安710119 中国科学院大学光电学院北京100049

针对空间天文、生物荧光、光谱测量等领域对高灵敏、大面阵探测器的应用需求,研制出基于感应读出方式的延迟线阳极光子计数成像探测器。该探测器由微通道板、延时线阳极以及读出电路组成,其中延时线阳极的性能直接影响探测器的成像质量... 详细信息

针对空间天文、生物荧光、光谱测量等领域对高灵敏、大面阵探测器的应用需求,研制出基于感应读出方式的延迟线阳极光子计数成像探测器。该探测器由微通道板、延时线阳极以及读出电路组成,其中延时线阳极的性能直接影响探测器的成像质量。作为一种电荷感应读出延时线阳极,该阳极利用信号到达的时间差解码入射光子的位置,可获得高的探测灵敏度和大的成像面积,同时简化了工艺难度并提升了可靠性。设计了感应读出延时线阳极,理论分析了探测器不同设计参数及材料对感应电荷量的影响,提出了解决异层电极间感应电荷量难以平衡的方法。据此研制出了收集面积为40 mm×40 mm的位敏阳极。测试结果表明该阳极信号传输衰减小于10%,极间串扰小于3%。利用该阳极进行了光子计数成像实验,获得了优于150μm的空间分辨率,为研制可应用于天文紫外光谱测量的大面阵、高灵敏探测器提供了理论依据及实验指导。

关键词：探测器光子计数成像位敏阳极空间分辨光谱测量

COMPUTATIONAL RESEARCH ON WAVE MAKING OF MOVING WIGLEY HULL IN TIME DOMAIN

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Journal of Hydrodynamics 2008年第4期20卷 469-476页

作者： yang xiang-hui YE Heng-kui FENG Da-kui LIU Juan College of Traffic Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China Ship Information Center Beijing 100085 China

Based on Green＇s theorem, a time domain numerical model was constructed to simulate wave making phenomenon caused by a moving ship. In this article, the Rankine sources and dipoles were placed on boundary surfaces （i.e., the ship surface and free surface）, and a time-stepping scheme was employed. Its unique characteristic is that steady state can be realized from initial value by employing the time-stepping scheme and unsteady free surface conditions. In time domain, if the results of unsteady flow problem tend to data stabilization after many time steps of computation, they could be regarded as the data of steady ones. This model could be employed to steady or unsteady problems. Theoretical reasoning and computational process of this method was described in detail The linear and nonlinear boundary conditions on body surface were studied, and the relative means to realize these boundary conditions in iterative computation were also discussed. Some proper parameters about the model of the Wigley hull were determined by many numerical tests, and their influences on wave making resistance and wave pattern were discussed. According to the comparison between numerical results and data available in relative references, the method used in this work is proven to be a reliable method in time domain. And the lattice reorganization in every time step computation is a feasible numerical approach.

关键词： Rankine source dipole time domain Wigley hull lattice reorganization time-stepping scheme Green's theorem

《园艺植物生物技术》课程思政教学改革与探索

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南方园艺 2024年第1期35卷 61-63页

作者：刘朝阳杨向晖秦永华赵杰堂张志珂华南农业大学园艺学院广东广州510642

《园艺植物生物技术》课程作为园艺专业的核心课程,在培养农业高质量人才中有着重要作用。针对该课程在课程思政教学过程中存在的一系列问题,提出了相应的改革思路与措施,积极引入课堂案例分析等多种灵活的教学手段,将思政元素有机融入... 详细信息

《园艺植物生物技术》课程作为园艺专业的核心课程,在培养农业高质量人才中有着重要作用。针对该课程在课程思政教学过程中存在的一系列问题,提出了相应的改革思路与措施,积极引入课堂案例分析等多种灵活的教学手段,将思政元素有机融入课程教学全过程,取得了良好的教学效果,同时也为农业高等院校该门课程及本专业其他课程思政建设提供一定参考和借鉴。

关键词：园艺植物生物技术课程思政教学改革

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Regio-and Stereoselective Polymerization of Bio-based Ocimene by Rare-Earth Metal Catalysts

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Chinese Journal of Polymer Science 2024年第2期42卷 223-229,I0008页

作者： Qi-Yuan Wang Li-Peng Sang Zhen Zhang yang Jiang hui Tian Xia Zhao xiang Guo Shi-hui Li State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei230026China Science and Technology on Aerospace Chemical Power Laboratory Hubei Institute of Aerospace ChemotechonologyXiangyang441003China Shanxi Coal Chemical Industry Technology Research Institute Xi’an710000China Hubei Institute of Aerospace Chemotechonology Xiangyang441003China

Coordination polymerization of renewable β-ocimene has been investigated using asymmetric diiminophosphinate lutetium complex1, β-diketiminate yttrium complex 2, bis(phosphino)carbazolide yttrium complex 3, half-sandwich benzyl fluorenyl scandium complex 4 and pyridyl-methylene-fluorenyl rare-metal complexes 5a–5c. Complexes 1, 4 and 5a–5c show trans-1,2-regioselectivities and high activities, of which 5c exhibits excellent isoselectivity(mmmm>99%). Conversely, complexes 2 and 3 promote β-ocimene polymerization to produce isotactic cis-1,4-polyocimenes(cis-1,4>99%, mm>95%). Diblock copolymers cis-1,4-PIP-block-cis-1,4-POc and cis-1,4-PBD-block-cis-1,4-POc are obtained in one-pot reactions of β-ocimene with isoprene and butadiene using complex 3. Epoxidation and hydroxylation of polyocimene afford functionalized polyolefins with enhanced T_(g)(from-20 ℃ to 79 ℃ and 74 ℃) and hydrophilicity.

关键词： Biobased monomer Terpenes Ocimene Rare-earths Polymerization Regio/stereoselectivity Elastomer

An integrative mathematical model of microwave ion thruster for mHz-frequency thrust noise analysis

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Chinese Journal of Aeronautics 2024年第4期37卷 121-136页

作者： xiang NIU hui LIU Daren YU Plasma Propulsion Laboratory Harbin Institute of TechnologyHarbin 150001China

Many high-precision space missions need thrusters to produce thrust with low noise to compensate for disturbances and ensure satellite platform stability. Microwave ion thruster is characterized with a wide thrust range and potential for these missions. A cost-effective and accurate mathematical model is crucial for mHz-frequency thrust noise analysis and feedback controller design. The Particle-In-Cell(PIC) and global models are two common simulation tools. The PIC model is characterized with high accuracy but huge computation cost, which is difficult to analyze long-time performance characteristics. Now, the global model is only used for the discharge chamber with low accuracy and cannot reflect ion extraction properties. In this paper, an integrative mathematical model is built for a 1-cm microwave ion thruster and can reflect ion beamlet divergence and impingement on the Accelerator Grid(AG). Simulation results show good agreement with experiments at 0.06 sccm. However, the model demonstrates worse consistency with experiments when the flux increases to 0.1 sccm, which may be because the influence of neutral gas on the Electron Cyclotron Resonance(ECR) is not considered in the model. A long-time(1000 s) simulation is conducted with this model under 35 μN. It takes 3 hrs, and the thrust noise reaches 1 μN/Hz^(0.5) at 1 mHz.

关键词： Electric propulsion Microwave ion thruster Integrative model Sheath property Ion beamlet divergence Thrust noise Plasma

Effect of solute Ce,Mn,and Si on mechanical properties of silicon steel:insights from DFT calculations

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Journal of Iron and Steel Research International 2024年第3期31卷 700-709页

作者： xiang-jun Liu Ji-chun yang hui-ping Ren Xiao-bin Jia Ming-yi Zhang Chang-qiao yang School of Materials and Metallurgy Inner Mongolia University of Science and TechnologyBaotou 014010Inner MongoliaChina Key Laboratory of Integrated Exploitation of Bayan Obo Multi-Metal Resource Inner Mongolia University of Science and TechnologyBaotou 014010Inner MongoliaChina Inner Mongolia North Heavy Industries Group Co. Ltd.Baotou 014010Inner MongoliaChina Inner Mongolia Metal Material Research Institute Baotou 014010Inner MongoliaChina

The influence of solute Ce,Mn,and Si on the mechanical properties of silicon steel was investigated by first-principles ***,Mn,and Si can all be solubilized in Fe *** significantly reduces the incompressibility and rigidity of the system but also significantly improves the toughness and *** effect of Mn on mechanical properties of the system is not *** has a significant effect on the improvement in incompressibility and rigidity but a limited effect on the improvement in toughness and *** metallic bond strength of Fe-Ce,Fe-Mn,and Fe-Si doped systems is weaker than that of the pure Fe system,which can be used to explain the reduction in the incompressibility and rigidity of these doped *** relatively high electron cloud density in the doped system may be responsible for the increase in toughness.

关键词： Silicon steel Rare earth First-principles calculation Elastic modulus Electronic structure

Efficient knowledge distillation for hybrid models:A vision transformer‐convolutional neural network to convolutional neural network approach for classifying remote sensing images

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IET Cyber-Systems and Robotics 2024年第3期6卷 1-22页

作者： Huaxiang Song Yuxuan Yuan Zhiwei Ouyang Yu yang hui xiang School of Geography Science and Tourism Hunan University of Arts and ScienceChangdeHunanChina

In various fields,knowledge distillation(KD)techniques that combine vision transformers(ViTs)and convolutional neural networks(CNNs)as a hybrid teacher have shown remarkable results in ***,in the realm of remote sensing images(RSIs),existing KD research studies are not only scarce but also lack *** issue significantly impedes the deployment of the notable advantages of ViTs and *** tackle this,the authors introduce a novel hybrid‐model KD approach named HMKD‐Net,which comprises a CNN‐ViT ensemble teacher and a CNN *** to popular opinion,the authors posit that the sparsity in RSI data distribution limits the effectiveness and efficiency of hybrid‐model knowledge *** a solution,a simple yet innovative method to handle variances during the KD phase is suggested,leading to substantial enhancements in the effectiveness and efficiency of hybrid knowledge *** authors assessed the performance of HMKD‐Net on three RSI *** findings indicate that HMKD‐Net significantly outperforms other cuttingedge methods while maintaining a significantly smaller ***,HMKD‐Net exceeds other KD‐based methods with a maximum accuracy improvement of 22.8%across various *** ablation experiments indicated,HMKD‐Net has cut down on time expenses by about 80%in the KD *** research study validates that the hybrid‐model KD technique can be more effective and efficient if the data distribution sparsity in RSIs is well handled.

关键词： hybrid‐model knowledge distillation remote sensing image classification vision transformer

Effect of short neuropeptide F signaling on larval feeding in Mythimna separata

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Insect Science 2024年第2期31卷 417-434页

作者： Mei-Mei Li Qi yang Li-hui Chen Yan-Ying Li Jun-xiang Wu xiang-Li Xu State Key Laboratory of Crop Stress Biology in Arid Areas College of Plant ProtectionNorthwest A&F UniversityYanglingShaanxi ProvinceChinaand School of Agricultural Sciences Jiangxi Agricultural UniversityNanchangChina

Mythimna separata is a notorious phytophagous pest which poses serious threats to cereal crops owing to the gluttony of the *** short neuropeptide F(sNPF)and its receptor sNPFR are involved in a diversity of physiological functions,especially in functions related to feeding in insects,it is a molecular target for pest ***,an sNPF and 2 sNPFRs were identified and cloned from *** analysis revealed that the sNPF and its receptors had a highly conserved RLRFamide C-terminus and 7 transmembrane domains,*** sNPF and its receptor genes were distributed across larval periods and tissues,but 2 receptors had distinct expression *** starvation-induced assay elucidated that sNPF and sNPFR expression levels were downregulated under food deprivation and recovered with subsequent *** interference knockdown of sNPF,sNPFR1,and sNPFR2 by injection of double-stranded RNA into larvae not only suppressed food consumption and increased body size and weight,but also led to decrease of glycogen and total lipid contents,and increase of trehalose compared with double-stranded green fluorescent protein ***,molecular docking was performed on the interaction mode between sNPFR protein and its ligand sNPF based on the 3-dimensional models constructed by AlphaFold;the results indicated that both receptors were presumably activated by the mature peptide *** results revealed that sNPF signaling played a considerably vital role in the feeding regulation of *** and represents a potential control target for this pest.

关键词： feeding regulation Mythimna separata pest control target RNA interference short neuropeptide F sNPF receptors

Inter-stage performance and energy characteristics analysis of electric submersible pump based on entropy production theory

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Petroleum Science 2024年第2期21卷 1354-1368页

作者： hui Wang yang yang Bin Xi Wei-Dong Shi Chuan Wang Lei-Lei Ji xiang-Yu Song Zhao-Ming He College of Hydraulic Science and Engineering Yangzhou UniversityYangzhou225009JiangsuChina College of Electrical and Mechanical Engineering Nanchang Institute of TechnologyNanchang330044JiangxiChina College of Mechanical Engineering Nantong UniversityNantong226019JiangsuChina National Research Center of Pumps Jiangsu UniversityZhenjiang212013JiangsuChina Zhejiang Zhenxing Petrochemical Machinery Co. Ltd.Ruian325204ZhejiangChina Department of Mechanical Engineering of Texas Tech University Lubbock79411TXUSA

The electric submersible pump(ESP) is a crucial apparatus utilized for lifting in the oil extraction *** lifting capacity is enhanced by the multi-stage tandem structure, but variations in energy characteristics and internal flow across stages are also introduced. In this study, the inter-stage variability of energy characteristics in ESP hydraulic systems is investigated through entropy production(EP) analysis,which incorporates numerical simulations and experimental validation. The EP theory facilitates the quantification of energy loss in each computational subdomain at all ESP stages, establishing a correlation between microscopic flow structure and energy dissipation within the system. Furthermore, the underlying causes of inter-stage variability in ESP hydraulic systems are examined, and the advantages and disadvantages of applying the EP theory in this context are evaluated. Consistent energy characteristics within the ESP, aligned with the distribution of internal flow structure, are provided by the EP theory, as demonstrated by our results. The EP theory also enables the quantitative analysis of internal flow losses and complements existing performance analysis methods to map the internal flow structure to hydraulic losses. Nonetheless, an inconsistency between the energy characterization based on EP theory and the traditional efficiency index when reflecting inter-stage differences is identified. This inconsistency arises from the exclusive focus of the EP theory on flow losses within the flow field, disregarding the quantification of external energy input to the flow field. This study provides a reference for the optimization of EP theory in rotating machinery while deeply investigating the energy dissipation characteristics of multistage hydraulic system, which has certain theoretical and practical significance.

关键词： Electric submersible pump(ESP) Entropy production theory Energy characteristics Inter-stage differences