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社区同群效应与居民网络消费扩容提质

武汉大学学报（哲学社会科学版） 2025年第1期78卷 146-159页

作者：尹振涛张珩中国社会科学院金融研究所北京100710 中国社会科学院大学应用经济学院北京100710

在百年未有之大变局下,扩内需、促消费已成为推动经济高效循环、满足人民美好生活需要的关键途径。作为人际互动与社会关系构建的关键场所,社区居民所形成的关系网络,不仅能强化居民之间的相互依赖,也能使居民消费行为产生同群效应。社... 详细信息

在百年未有之大变局下,扩内需、促消费已成为推动经济高效循环、满足人民美好生活需要的关键途径。作为人际互动与社会关系构建的关键场所,社区居民所形成的关系网络,不仅能强化居民之间的相互依赖,也能使居民消费行为产生同群效应。社区同群效应的信息传递与知识溢出,在促进居民网络消费扩容提质的同时,可以通过增加网络消费信贷、提升消费等级和降低居民依赖心理,使得低于参考点的居民受到激励,实现网络消费的扩容提质,这一点在男性和银发群体以及处于中小城市和农村地区的居民中表现得更为明显。社区同群效应对居民网络消费所产生的这种积极作用,为建立社区交流机制、设计符合居民需求特点的网络消费信贷体系、树立理性消费观和构建能释放内需动力的消费机制提供了新的实证证据,也丰富了居民消费领域的研究。

关键词：社区同群效应网络消费扩容提质网络消费信贷

Value iteration algorithm for continuous-time linear quadratic stochastic optimal control problems

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Science China(Information Sciences) 2024年第2期67卷 170-180页

作者： Guangchen WANG heng zhang School of Control Science and Engineering Shandong University

In this study, we investigate a continuous-time infinite-horizon linear quadratic stochastic optimal control problem with multiplicative noise in control and state variables. Using the techniques of stochastic stability, exact observability, and stochastic approximation, a value iteration algorithm is developed to solve the corresponding generalized algebraic Riccati equation. Unlike the existing policy iteration algorithm, this algorithm does not rely on an initial stabilizing control. Further, this algorithm can also be used to compute policy evaluation steps that arise in the policy iteration algorithm. Herein, a simulation example is provided to validate the obtained results.

关键词： stochastic systems optimal control linear quadratic stochastic problem generalized algebraic Riccati equation value iteration algorithm

Source free unsupervised domain adaptation for electro-mechanical actuator fault diagnosis

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Chinese Journal of Aeronautics 2023年第4期36卷 252-267页

作者： Jianyu WANG heng zhang Qiang MIAO College of Electrical Engineering Sichuan UniversityChengdu 610065China

A common necessity for prior unsupervised domain adaptation methods that can improve the domain adaptation in unlabeled target domain dataset is access to source domain data-set and target domain dataset ***,data privacy makes it not always possible to access source domain dataset and target domain dataset in actual industrial equipment simulta-neously,especially for aviation component like Electro-Mechanical Actuator(EMA)whose dataset are often not shareable due to the data copyright and *** address this problem,this paper proposes a source free unsupervised domain adaptation framework for EMA fault *** proposed framework is a combination of feature network and ***,source domain datasets are only applied to train a source ***,the well-trained source model is trans-ferred to target domain and classifier is frozen based on source domain ***,nearest centroid filtering is introduced to filter the reliable pseudo labels for unlabeled target domain data-set,and finally,supervised learning and pseudo label clustering are applied to fine-tune the trans-ferred *** comparison with several traditional unsupervised domain adaptation methods,case studies based on low-and high-frequency monitoring signals on EMA indicate the effectiveness of the proposed method.

关键词： Data privacy Electro-mechanical actuator Pseudo-label clustering Nearest centroid filtering Unsupervised domain adaptation

Interface materials for perovskite solar cells

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Rare Metals 2021年第11期40卷 2993-3018页

作者： Yi-heng zhang Yuan Li School of Materials Science and Engineering South China University of TechnologyGuangzhou 510641China

Perovskite solar cells exhibit great potential to become commercial photovoltaic technology due to their high power conversion efficiency,low cost,solution processability,and facile large-area device *** engineering plays a significant role to optimize device *** the anode in the inverted devices,this review introduces the progress on the modification of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)including chemical structure alteration,physical doping,and solution *** present the recent advances of dopant-free hole transport materials widely applied in mesoporous and conventional devices,outlining their innovation with novel molecular design concepts toward promising material properties,and device *** the cathode,various metal oxide and organic electron transport materials are covered and the different modification strategies and related mechanisms are *** importantly,simple synthesis process,inexpensive raw materials and highly reproducible photovoltaic performance are the main consideration for the design of all the interface ***,an outlook and some suggestions regarding the future interface engineering are proposed based on the summary of the current development status and working mechanism of interface materials.

关键词： Perovskite solar cells Interface Hole transport materials Electron transport materials PEDOT:PSS

Preparation,optical properties and energy transfer of SrLaAlO_(4):Dy^(3+),Eu^(3+)

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Journal of Rare Earths 2024年第11期42卷 2058-2067,I0003页

作者： Wei Chen heng zhang Desheng Zhu School of Physic and Optoelectronic Engineering Yangtze UniversityJingzhou434023China

A series of Dy^(3+)/Eu^(3+) single doped and co-doped SrLaAlO_(4) phosphors was synthesized by the traditional high-temperature solid-state method,and their structure,morphology and optical properties were *** X-ray diffraction(XRD) shows a small amount of doping with Dy^(3+) and Eu^(3+) does not change the crystal structure of the matrix SrLaAlO_(4) and the best synthesis temperature is 1450℃.The scanning electron microscopy(SEM) indicates the particle size directly ranges from 1 to 5μm roughly and the energy dispersive spectroscopy(EDS) patterns show that SrLaAlO_(4):Dy^(3+) phosphor and SrLaAlO_(4):Dy^(3+),Eu^(3+) phosphor were successfully ***_(4):Dy^(3+) phosphor can be effectively excited by near-ultraviolet light,producing two strong emission lights at 483 nm(blue light) and 579 nm(yellow light),presenting a cold white light;SrLaAlO_(4):Eu^(3+) phosphor can be effectively excited by nearultraviolet light,producing red lights at 622 nm;the characteristic emission peaks of Dy^(3+) and Eu^(3+)can be shown simultaneously under the same excitation wavelength in SrLaAlO_(4):Dy^(3+), Eu^(3+) *** changing the relative doping concentration ratio of Dy^(3+) and Eu^(3+),the modulation of SrLaAlO_(4):Dy^(3+),Eu3+phosphor from cold white to warm white light can be *** addition,the study of the luminescent mechanism and lifetime shows that there is energy transfer between Dy^(3+) and Eu^(3+) in SrLaAlO_(4):Dy^(3+),Eu^(3+) phosphor.

关键词： High-temperature solid-phase method SrLaAlO_(4):Dy^(3+) Eu^(3+) Luminescence properties White phosphor Energy transfer Rare earths

Double-decoupled inverse design of natural laminar flow nacelle under transonic conditions

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Chinese Journal of Aeronautics 2023年第6期36卷 1-18页

作者： heng zhang Jie LI Zhao YANG School of Aerospace Engineering Tsinghua UniversityBeijing 100084China School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China

The inverse design based on the pressure distribution is an essential approach to realize the improvement of Natural Laminar Flow(NLF) performance for nacelles. However, the direct definition of target pressure distribution at design point is challenging for the dilemma to consider the constraints of shock wave and laminar flow at the same time. In addition, the universality of method will be limited when the inverse design is strongly coupled with the solver. Thus, a double-decoupled methodology based on the relationship of pressure distributions between design and off-design points is proposed in this paper, which realizes the decoupling of constraints in shock wave and laminar flow on target pressure distribution as well as the decoupling of flow field solution and inverse design method. Aimed at an isolated flow-through-nacelle of high bypass ratio, the target pressure distribution with appropriate favorable gradient and shock-free feature is defined according to physical principles at the off-design point of Ma = 0.80 while the transonic and laminar performance are examined at the design point of Ma = 0.85. The solution of flow field is based on γ-Re_(θ) transition model and the inverse design is based on residual-correction method. With the inverse design starting from off-design point, the performance of shock wave and laminar flow at design point are both improved. The local shock wave after the lip of nacelle is eliminated effectively while the streamwise length of laminar flow region is doubled and exceeds to 30% of the chord length. The percentage of drag reduction for outboard surface is 12.7% for friction drag, 7.8%for pressure drag and 10.5% for total drag. The effects of inverse design on the process of transition are analyzed with detailed flow features. The robustness of laminar flow is examined under different variation factors of freestream which are deviated from the design point.

关键词： Drag reduction Inverse design method Nacelle Natural laminar flow Transonic

An attention graph stacked autoencoder for anomaly detection of electro-mechanical actuator using spatio-temporal multivariate signals

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Chinese Journal of Aeronautics 2024年第9期37卷 506-520页

作者： Jianyu WANG heng zhang Qiang MIAO College of Electrical Engineering Sichuan UniversityChengdu 610065China

Health monitoring of electro-mechanical actuator(EMA)is critical to ensure the security of *** is difficult or even impossible to collect enough labeled failure or degradation data from actual *** autoencoder based on reconstruction loss is a popular model that can carry out anomaly detection with only consideration of normal training data,while it fails to capture spatio-temporal information from multivariate time series signals of multiple monitoring *** mine the spatio-temporal information from multivariate time series signals,this paper proposes an attention graph stacked autoencoder for EMA anomaly ***,attention graph con-volution is introduced into autoencoder to convolve temporal information from neighbor features to current features based on different weight ***,stacked autoencoder is applied to mine spatial information from those new aggregated temporal ***,based on the bench-mark reconstruction loss of normal training data,different health thresholds calculated by several statistic indicators can carry out anomaly detection for new testing *** comparison with tra-ditional stacked autoencoder,the proposed model could obtain higher fault detection rate and lower false alarm rate in EMA anomaly detection experiment.

关键词： Anomaly detection Spatio-temporal informa-tion Multivariate time series signals Attention graph convolution Stacked autoencoder

Protecting genes from RNA silencing by destroying aberrant transcripts

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Science China(Life Sciences) 2015年第6期58卷 613-615页

作者： zhang heng ZHU JianKang Shanghai Center for Plant Stress Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Department of Horticulture and Landscape Architecture Purdue University

Gene expression is intensively regulated at the transcript level. It is the rate of transcription and the rate of degrada- tion that together determine the steady-state level of a specific transcript. A whole-genome study indicates that the half-life of Arabidopsis transcripts varies from 0.2 to 〉24 h, indicating large variations in the turnover rate of specific transcripts, which is related to their biological functions.

关键词：转录水平 RNA沉默基因保护异常基因表达调控生物学功能降解作用全基因组

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

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

作者： Yunkai DENG Yongwei zhang Zhimin zhang Wei 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, which 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)