检索结果-南通市图书馆

Orthogonal waveform design with fractional programming on the ambiguity suppression of SAR systems

Science China(information Sciences) 2024年第9期67卷 263-279页

作者： Yunkai DENG Yongw.i zhang Zhimin zhang w.i wANG Heng zhang Department of Space Microwave Remote Sensing System Aerospace Information Research InstituteChinese Academy of Sciences

waveform diversity(wD) represents a dynamic and transformative technology widely used in radar systems to enhance sensitivity and discrimination capabilities. Recently, wD techniques have been extensively explored for their potential ambiguity suppression within synthetic aperture radar(SAR) *** these, the alternate transmitting mode combined with orthogonal waveforms emerges as a particularly promising solution. This study focuses on optimizing the power spectrum density(PSD) of signals to design and generate an orthogonal waveform pair that achieves both a low cross-correlation-to-autocorrelation ratio(CAR) and satisfactory imaging performance. initially, we construct a fractional programming model with convex constraints to minimize the CAR. To address this challenge, we introduce an iterative optimization procedure for the PSD variable, w.ich sequentially reduces the CAR. Each optimization step can be efficiently solved using a quadratically constrained quadratic program, ensuring that the resulting computational complexity remains low. Building on the optimized PSD, we established a parametric piecewise linear model to generate an orthogonal waveform pair. This model not only maintains a low CAR but achieves satisfactory imaging performance in real-time applications. Consequently, this orthogonal waveform pair effectively suppresses range ambiguity in SAR systems. Finally, we demonstrated the practicability and effectiveness of the proposed orthogonal waveforms through detailed simulation experiments, specifically targeting ambiguity suppression in conventional quad-polarization SAR systems.

关键词： synthetic aperture radar (SAR) waveform diversity (wD) ambiguity suppression orthogonal waveform fractional programming power spectrum density (PSD)

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Single Fe atom-anchored manganese dioxide for efficient removal of volatile organic compounds in refrigerator

引用

Nano Research 2024年第5期17卷 3927-3933页

作者： Yiwen wang Jun zhang Yongfei zhang Yu zhang Zhe wang Jing wang Yuen wu Department of Endocrinology the First Affiliated Hospital of USTCDivision of Life Science and MedicineUniversity of Science and Technology of ChinaHefei 230001China School of Chemistry and Materials Science University of Science and Technology of ChinaHefei 230026China Hefei Hualing Co. LtdHefei 230088China Linkway Technology Co. LtdResearch Institute of Single Atom Catalysts Industry TechnologyNanning 530000China

The efficient and rapid removal of volatile organic compounds(VOCs)holds significant importance for ensuring food quality and human health,particularly within the low-temperature confined spaces in ***,achieving effective VOCs degradation under such conditions poses challenges in terms of activating inert bonds and facilitating mass *** this study,we propose a novel solution by designing a cleaner module that incorporates 1.07%single Fe atom-anchored manganese dioxide catalysts(FeSAs-MnO_(2)).The combination of single Fe atoms and defect-rich MnO_(2) substrate efficiently activates molecular oxygen,leading to enhanced generation of highly reactive oxygen species(ROS).Non-thermal plasma(NTP)and circulating fan are introduced to facilitate the regeneration of catalytic activity and improve mass *** FeSAs-MnO_(2) cleaner module demonstrates exceptional performance in trimethylamine(TMA)removal,achieving a conversion efficiency of 98.9%for 9 ppm within just 9 ***,accelerated aging tests predict an extended service life of up to 45 years for the FeSAs-MnO_(2) cleaner module,surpassing the expected lifespan of refrigerators significantly.

关键词： single atom catalysts volatile organic compounds(VOCs) trimethylamine(TMA) non-thermal plasma(NTP) refrigerator

来源：

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

Self-assembly of perovskite nanocrystals:From driving forces to applications

引用

Journal of Energy Chemistry 2024年第1期88卷 561-578,I0013页

作者： Yi Li Fei zhang School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072China Collaborative innovation Center of Chemical Science and Engineering(Tianjin) Tianjin 300072China

Self-assembly of metal halide perovskite nanocrystals(NCs)into superlattices can exhibit unique collective properties,w.ich have significant application values in the display,detector,and solar cell *** review discusses the driving forces behind the self-assembly process of perovskite NCs,and the commonly used self-assembly methods and different self-assembly structures are ***,we summarize the collective optoelectronic properties and application areas of perovskite superlattice ***,we conclude with an outlook on the potential issues and future challenges in developing perovskite NCs.

关键词： Self-assembly Metal halide perovskite Nanocrystals Driving forces

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Recent advances in multifunctional shape memory photonic crystals and practical applications

引用

Nano Research 2024年第1期17卷 79-96页

作者： Yong Qi Shufen zhang State Key Laboratory of Fine Chemicals Frontier Science Center for Smart MaterialsDalian University of TechnologyDalian 116024China

Shape memory photonic crystals(SMPCs)are smart composite materials with changeable structural color integrated by shape memory polymer and photonic *** can produce one or more temporary shapes through nanoscale deformation,memorizing current *** can be recovered to their original shapes or some intermediate states under external stimuli,accompanied by the variation of structural *** porous carriers with built-in sensing properties,SMPCs promoted the interdisciplinary development of nanophotonic technology in materials science,environmental engineering,biomedicine,chemical engineering,and ***,the recent progress on multifunctional SMPCs and practical applications,including traditional and cold programmable SMPCs,is summarized and *** primary concern is shape programming at the nanoscale that has demonstrated numerous attractive functions,including smart sensing,ink-free printing,solvent detection,reprogrammable gradient wetting,and controllable bubble transportation,under variations of the surface *** aims to figure out the nanoscale shape memory effects on structural color conversion and additional performance,inspiring the fabrication of the next generation of ***,perspectives on future research directions and applications are also *** is believed that multifunctional SMPCs are powerful nanophotonic tools for the interdisciplinary development of numerous disciplines in the future.

关键词： photonic crystal shape memory structural color cold programmable shape recovery

来源：

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

Analytical modeling and approaches of multihelix cables incorporating with interwire mutual contacts

引用

Applied Mathematics and Mechanics(English Edition) 2024年第9期45卷 1633-1654页

作者： Zhichao zhang Xingzhe wANG Key Laboratory of Mechanics on Disaster and Environment in western China The Ministry of Education of ChinaCollege of Civil Engineering and MechanicsKey Laboratory of Special Function Materials and Structure Design of Ministry of EducationLanzhou UniversityLanzhou 730000China College of Civil Science and Engineering Yangzhou UniversityYangzhou 225127Jiangsu ProvinceChina

This study aims to develop an analytical model based on the curve beam theory to capture the mechanical response of a multihelix cable considering the internal contact ***,a double-helix cable subjected to axial tension and torsion is analyzed,and both the line and point contacts between the neighboring wires and strands are considered via an equivalent homogenized ***,the proposed theoretical model is extended to a hierarchical multihelix cable with mutual contact displacements by constructing a recursive relationship between the high-and low-level multihelix *** global tensile stiffness and torsional stiffness of the double-helix cable are successfully *** results are validated by a finite element(FE)model,and are found to be consistent with the findings of previous *** is shown that the contact deformations in multihelix cables significantly affect their equivalent mechanical stiffness,and the contact displacements are remarkably enhanced as the helix angles *** study provides insights into the interwire/interstrand mutual contact effects on global and local responses.

关键词： wordshierarchical multihelix cable mutual contact effect mechanical response effective stiffness

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Study on Coded Permutation Entropy of Finite Length Gaussian w.ite Noise Time Series

引用

Chinese Journal of Electronics 2024年第1期33卷 185-194页

作者： Huihui SUN Xiaofeng zhang School of Physics and information Technology Shaanxi Normal University

As an extension of permutation entropy(PE), coded permutation entropy(CPE) improves the performance of PE by making a secondary division for ordinal patterns defined in PE. in this study, we provide an exploration of the statistical properties of CPE using a finite length Gaussian w.ite noise time series theoretically. By means of the Taylor series expansion, the approximate expressions of the expected value and variance of CPE are deduced and the Cramér-Rao low bound(CRLB) is obtained to evaluate the performance of the CPE estimator. The results indicate that CPE is a biased estimator, but the bias only depends on relevant parameters of CPE and it can be easily corrected for an arbitrary time series. The variance of CPE is related to the encoding patterns distribution,and the value converges to the CRLB of the CPE estimator when the time series length is large enough. For a finitelength Gaussian w.ite noise time series model, the predicted values can match well with the actual values, w.ich further validates the statistic theory of CPE. Using the theoretical expressions of CPE, it is possible to better understand the behavior of CPE for most of the time series.

关键词： Time series analysis w.ite noise Predictive models Taylor series Entropy Encoding Time measurement

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Robust adaptive radar beamforming based on iterative training sample selection using kurtosis of generalized inner product statistics

引用

Journal of Systems Engineering and Electronics 2024年第1期35卷 24-30页

作者： TiAN Jing zhang w.i School of information and Electronics Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Electromagnetic Space Security Chengdu 610036China

in engineering application,there is only one adaptive w.ights estimated by most of traditional early warning radars for adaptive interference suppression in a pulse reputation interval(PRi).Therefore,if the training samples used to calculate the w.ight vector does not contain the jamming,then the jamming cannot be removed by adaptive spatial *** the w.ight vector is constantly updated in the range dimension,the training data may contain target echo signals,resulting in signal cancellation *** cope with the situation that the training samples are contaminated by target signal,an iterative training sample selection method based on non-homogeneous detector(NHD)is proposed in this paper for updating the w.ight vector in entire range *** principle is presented,and the validity is proven by simulation results.

关键词： adaptive radar beamforming training sample selection non-homogeneous detector electronic jamming jamming suppression

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Design Research of a Novel Aftercool-Humidifier Concept for Humid Air Turbine Cycle

引用

Journal of Thermal Science 2024年第3期33卷 951-969页

作者： zhang Junzheng XU Zhen School of Energy and Power Engineering Shandong UniversityJi’nan250061China Shandong Engineering Laboratory for High-efficiency Energy Conservation and Energy Storage Technology&Equipment Shandong UniversityJi’nan250061China

Humid air turbine cycle(HAT)has potential of electrical efficiencies comparable to combined cycle,with lower investment cost and NO_(x) *** typical heat exchanger network of HAT consists of intercooler(if there is),aftercooler,recuperator,economizer and humidifier,w.ich brings higher efficiency but makes the system more *** simplify HAT layout,a novel humidifier concept is proposed by integrating the aftercooler into traditional counter-current *** on this concept,a one-dimensional model including pressure drop and exergy calculation is established to distinguish the thermodynamic and hydrodynamic characteristics,and then the structural parameters,such as the number of rows and columns,tube diameter,pitch and type for a micro HAT are *** results show that the aftercool-humidifier plays the same role as original aftercooler and humidifier,and can match the in-tube air,out-tube air and water stream well with lower *** the case of micro HAT cycle,the volume of heat and mass transfer area can be reduced by 47%compared with traditional *** major thermal resistance occurred in the convection heat transfer process inside the tube;however,using enhanced tube cannot effectively improve the compactness of device.

关键词： humid air turbine cycle humidifier thermodynamic analysis one-dimensional model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

indispensable gutter layers in thin-film composite membranes for carbon capture

引用

Green Energy & Environment 2024年第8期9卷 1220-1238页

作者： Gengyi zhang Haiqing Lin Department of Chemical and Biological Engineering University at Buffalo The State University at New York

industrial thin-film composite(TFC) membranes achieve superior gas separation properties from high-performance selective layer materials,w.ile the success of membrane technology relies on high-performance gutter layers to achieve production scalability and low-cost manufacturing. However, the current literature predominantly focuses on the design of polymer architectures to obtain high permeability and selectivity, w.ile the art of fabricating gutter layers is usually safeguarded by industrial manufacturers and appears lackluster to academic researchers. This is the first report aiming to provide a comprehensive and critical review of state-of-the-art gutter layer materials and their design and modification to enable TFC membranes with superior separation performance. we first elucidate the importance of the gutter layer on membrane performance through modeling and experimental results. Then various gutter layer materials used to obtain high-performance composite membranes are critically reviewed, and the strategies to improve their compatibility with the selective layer are highlighted, such as oxygen plasma treatment, polydopamine deposition, and surface grafting. Finally, we present the opportunities of the gutter layer design for practical applications.

关键词： Thin-film composite membranes Gutter layer Gas separation Carbon capture

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

User Purchase intention Prediction Based on improved Deep Forest

引用

Computer Modeling in Engineering & Sciences 2024年第4期139卷 661-677页

作者： Yifan zhang Qiancheng Yu Lisi zhang School of Computer Science and Engineering North Minzu UniversityYinchuan750030China Laboratory of Graphics and images of the State Ethnic Affairs Commission North Minzu UniversityYinchuan750030China

widely used deep neural networks currently face limitations in achieving optimal performance for purchase intention prediction due to constraints on data volume and hyperparameter *** address this issue,based on the deep forest algorithm and further integrating evolutionary ensemble learning methods,this paper proposes a novel Deep Adaptive Evolutionary Ensemble(DAEE)*** model introduces model diversity into the cascade layer,allowing it to adaptively adjust its structure to accommodate complex and evolving purchasing behavior ***,this paper optimizes the methods of obtaining feature vectors,enhancement vectors,and prediction results within the deep forest algorithm to enhance the model’s predictive *** demonstrate that the improved deep forest model not only possesses higher robustness but also shows an increase of 5.02%in AUC value compared to the baseline ***,its training runtime speed is 6 times faster than that of deep models,and compared to other improved models,its accuracy has been enhanced by 0.9%.

关键词： Purchase prediction deep forest differential evolution algorithm evolutionary ensemble learning model selection

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：