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Understanding Urban Vitality from the Economic and Human Activities Perspective:A Case Study of Chongqing,China

Chinese Geographical Science 2024年第1期34卷 52-66页

作者： YANG Fiona Fan LIN Geng lei yubing WANG Ying YI Zheng School of Geography and Planning Sun Yat-sen UniversityGuangzhou510006China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai519100China Chongqing Planning and Design Institute Chongqing401147China

The literature on urban vitality tends to focus on the built *** paper argues that some important processes in shaping vitality may be overlooked without examining the intensity and diversity of economic and human *** newly developed spatial big data and adopting the methods of multi-indicator measurement and spatial analysis methods,we analyzed the pattern of urban vitality in Chongqing,a provincial city in western China and,on this basis,evaluated the creation and maintenance of urban vitality from the economic and human activities *** findings indicate that the impacts of economic and human activities are positive and *** the three intensity and diversity indicators,economic intensity and population density show an effect on urban vitality stronger than that of economic ***,economic diversity has the strongest superposition or interactive effect,and is thus an important foundation *** positive effect of population density on urban vitality is largely a result of Chongqing’s jobs-housing *** case of Chongqing highlights the importance of topographic features,historical inheritance,large-scale migration,and cultural activities in shaping the distinctive vitality pattern of a *** study contends that the creation and maintenance of urban vitality can not be fully explained without incorporating the impacts of economic and human *** contributes to a comprehensive measurement of urban vitality and enriches its connotations.

关键词： urban vitality economic diversity economic intensity population density Chongqing,China

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Understanding Urban Vitality from the Economic and Human Activities Perspective: A Case Study of Chongqing, China

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中国地理科学（英文版） 2024年第1期

作者： YANG Fiona Fan LIN Geng lei yubing WANG Ying YI Zheng

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New insights in nano-copper chromite catalyzing ultrafine AP:Evaluation of dispersity and mixing uniformity

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Defence Technology（防务技术） 2024年第2期32卷 120-133页

作者： Yong Kou Peng Luo lei Xiao Yanping Xin Guangpu Zhang yubing Hu Junqing Yang Hongxu Gao Fengqi Zhao Wei Jiang Gazi Hao National Special Superfine Powder Engineering Research Center of China School of Chemistry and Chemical EngineeringNanjing University of Science and TechnologyNanjing210094China Xi'an North Huian Chemical Industry Co.Ltd Xi'an710302China Xi'an Modern Chemistry Research Institute Xi'an710065China

Improving the application of nanomaterials has always been a research hotspot in the field of energetic materials(EMs)due to their obvious catalytic effect on the EMs,especially the uniformly dispersed ***,few studies have reported the dispersion of *** this study,the dispersity and mixing uniformity of nano-CuCr_(2)O_(4)was evaluated based on the difference of solid UV light absorption between the nano-catalytic materials and *** nano-CuCr_(2)O_(4)/ultrafine AP composites with different dispersity of nano-CuCr_(2)O_(4)were prepared by manual grinding and mechanical grinding with different grinding strength and griding *** then,the absorbance of different samples at 212 nm was obtained by solid UV testing due to the high repeatability of the absorbance at 210-214 nm for three parallel experiments,and the dispersity of different samples was calculated through the established difference ***,the samples were characterized by XRD,IR,SEM,EDS,DSC and TG-MS,which confirmed that different mixing methods did not change the structure of the samples(XRD and IR),and the mixing uniformity improved with the increase of grinding strength and grinding time(SEM and EDS).The scientificity and feasibility of the difference equation were further verified by *** dispersity of nano-CuCr_(2)O_(4)exhibits a positive intrinsic relationship with its catalytic performance,and the uniformly dispersed nano-CuCr_(2)O_(4)significantly reduces the thermal decomposition temperature of ultrafine AP from 367.7 to 338.8℃.The TG-MS patterns show that the dispersed nano-CuCr_(2)O_(4)advanced the thermal decomposition process of ultrafine AP by about 700 s,especially in the high temperature decomposition stage,and the more concentrated energy release characteristic is beneficial to further enhance the energy performance of AP-based *** above conclusions show that the evaluation method of dispersity based on solid UV curves could pro

关键词： Nano-CuCr_(2)O_(4) Ultrafine AP Dispersity UVeVis diffuse reflectance spectroscopy Thermal decomposition

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产业与地形因素影响下的山地城市职住空间关系——以重庆市主城九区为例

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热带地理 2022年第4期42卷 616-628页

作者：雷玙冰林耿杨忍王英中山大学地理科学与规划学院广州510006 南方海洋科学与工程广东省实验室(珠海) 广东珠海519000 重庆市规划设计研究院重庆401120

选择重庆主城九区作为典型案例,基于百度慧眼识别的就业人口与居住人口数据,通过测算就业-居住偏离度指数分析其人口分布特征与职住空间关系,划分就业主导区、基本匹配区与居住主导区。并基于全国第四次经济普查数据,在对产业进行综合... 详细信息

选择重庆主城九区作为典型案例,基于百度慧眼识别的就业人口与居住人口数据,通过测算就业-居住偏离度指数分析其人口分布特征与职住空间关系,划分就业主导区、基本匹配区与居住主导区。并基于全国第四次经济普查数据,在对产业进行综合因子分析基础上,定量化识别产业综合因子和地形因子对重庆主城九区职住空间匹配性影响。结果表明:1)重庆市主城区的就业与居住人口空间分布趋势具有一致性特征,整体上呈现“中间高、四周低”的特征;2)重庆市主城区的职住空间基本平衡,街道尺度上职住偏离特征不显著,但城市多组团的中心地区职住空间匹配特征稍有差异,呈现主中心(解放碑)职住平衡度低、4个副中心职住平衡度高的格局;3)空间回归模型表明,综合性服务产业因子和生产性服务产业因子强化了职住分离程度,社会性服务产业因子、制造业因子和地形起伏度降低了职住空间差异。总体上,产业布局与地形地貌是重庆主城区职住空间关系的重要影响因素,二者与政府规划、交通条件和居民生活相互补充、共同作用,塑造了重庆主城现今协调发展的就业-居住空间格局。

关键词：山地城市职住空间关系就业居住偏离度产业布局地形地貌空间回归模型重庆市

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Metarelation2vec:A Metapath-Free Scalable Representation Learning Model for Heterogeneous Networks

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Tsinghua Science and Technology 2024年第2期29卷 553-575页

作者： lei Chen Yuan Li Yong lei Xingye Deng School of Information and Electrical Engineering Hunan University of Science and TechnologyXiangtan 411201China School of Computer Science and Engineering Hunan University of Science and TechnologyXiangtan 411201China

Metapaths with specific complex semantics are critical to learning diverse semantic and structural information of heterogeneous networks(HNs)for most of the existing representation learning ***,any metapaths consisting of multiple,simple metarelations must be driven by domain *** sensitive,expensive,and limited metapaths severely reduce the flexibility and scalability of the existing models.A metapath-free,scalable representation learning model,called Metarelation2vec,is proposed for HNs with biased joint learning of all metarelations in a bid to address this ***,a metarelation-aware,biased walk strategy is first designed to obtain better training samples by using autogenerating cooperation probabilities for all metarelations rather than using expert-given ***,grouped nodes by the type,a common and shallow skip-gram model is used to separately learn structural proximity for each node ***,grouped links by the type,a novel and shallow model is used to separately learn the semantic proximity for each link ***,supervised by the cooperation probabilities of all meta-words,the biased training samples are thrown into the shallow models to jointly learn the structural and semantic information in the HNs,ensuring the accuracy and scalability of the *** experimental results on three tasks and four open datasets demonstrate the advantages of our proposed model.

关键词： metarelation random walk heterogeneous network metapath representation learning

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Structural energy storage composites based on modified carbon fiber electrode with metal-organic frame enhancing layered double hydroxide

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Nano Research 2024年第3期17卷 1552-1563页

作者： Jinrui Ye Zhongbao Wang Qin lei lei Sun Jinfeng Gu School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Tangshan Research Institute Beijing Institute of TechnologyTangshan 063000China School of Materials Science and Engineering Shenyang Jianzhu UniversityShenyang 110168China Department of Stomatology PLA Strategic Support Force Characteristic Medical CenterBeijing 100101China Beijing Electromechanical Engineering Research Institute Beijing 100074China

Structural energy storage composites present advantages in simultaneously achieving structural strength and electrochemical *** of carbon fiber electrodes and resin structural electrolytes in energy storage composite poses challenges in maintaining good mechanical and electrochemical properties at reasonable cost and ***,we report a simple method to fabricate structural supercapacitor using carbon fiber electrodes(modified by Ni-layered double hydroxide(Ni-LDH)and in-situ growth of Co-metal-organic framework(Co-MOF)in a two-step process denoted as Co-MOF/Ni-LDH@CF)and bicontinuous-phase epoxy resin-based structural ***-MOF/Ni-LDH@CF as electrode material exhibits improved specific capacity(42.45 F·g^(-1))and cycle performance(93.3%capacity retention after 1000 cycles)in a three-electrode *** bicontinuous-phase epoxy resin-based structural electrolyte exhibits an ionic conductivity of 3.27×10^(-4) S·cm^(-1).The fabricated Co-MOF/Ni-LDH@CF/SPE-50 structural supercapacitor has an energy density of 3.21 Wh·kg^(-1) at a power density of 42.25 W·kg^(-1),whilst maintaining tensile strength and modulus of 334.6 MPa and 25.2 *** results show practical potential of employing modified commercial carbon fiber electrodes and epoxy resin-based structural electrolytes in structural energy storage applications.

关键词： carbon fiber electrode structural electrolyte structural energy storage composites supercapacitor

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Imaging momentum-space Cooper pair formation and its competition with the charge density wave gap in a kagome superconductor

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 142-150页

作者： Yiming Sun yubing Tu Yang Luo Shuikang Yu Hongyu Li Yunmei Zhang Ping Wu Zhuying Wang Fan Zhang Wanru Ma Zuowei Liang Jianjun Ying Tao Wu Ziji Xiang Junfeng He lei Shan Zhenyu Wang Xianhui Chen Department of Physics CAS Key Laboratory of Strongly Coupled Quantum Matter Physicsand Hefei National LaboratoryUniversity of Science and Technology of ChinaHefei 230026China Information Materials and Intelligent Sensing Laboratory of Anhui Province Institutes of Physical Science and Information TechnologyAnhui UniversityHefei 230601China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China

The superconducting ground state of kagome metals AV_(3)Sb_(5)(where A stands for K,Rb,or Cs)emerges from an exotic charge density wave(CDW)state that potentially breaks both rotational and time reversal ***,the specifics of the Cooper pairing mechanism,and the nature of the interplay between these two states remain elusive,largely due to the lack of momentum-space(k-space)superconducting energy gap *** implementing Bogoliubov quasiparticle interference(B QPI)imaging,we obtain k-space information on the multiband superconducting gap structureΔ_(SC)^(i)(k)in pristine CsV_(3)Sb_(5).We show that the estimated energy gap on the vanadium d_(xy/x^(2)-y^(2))orbital is anisotropic but nodeless,with a minimal value located near the M ***,a comparison ofΔ_(SC)^(i)(k)with the CDW gapΔ_(CDW)^(i)(k)obtained by angle-re solved photoemission spectro scopy(ARPES)reveals direct k-space competition between the se two order parameters,i.e.,the opening of a large(small)CDW gap at a given momentum corresponds to a small(large)superconducting *** the long-range CDW order is suppressed by replacing vanadium with titanium,we find a nearly isotropic energy gap on both the V and Sb *** information will be critical for identifying the microscopic pairing mechanism and its interplay with intertwined electro nic orders in this kagome superconductor family.

关键词： kagome lattice charge density wave superconducting energy gap scanning tunneling microscopy

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DCVAE-adv:A Universal Adversarial Example Generation Method for White and Black Box Attacks

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Tsinghua Science and Technology 2024年第2期29卷 430-446页

作者： lei Xu Junhai Zhai College of Mathematics and Information Science Hebei UniversityBaoding 071002China

Deep neural network(DNN)has strong representation learning ability,but it is vulnerable and easy to be fooled by adversarial *** order to handle the vulnerability of DNN,many methods have been *** general idea of existing methods is to reduce the chance of DNN models being fooled by observing some designed adversarial examples,which are generated by adding perturbations to the original *** this paper,we propose a novel adversarial example generation method,called *** from the existing methods,DCVAE-adv constructs adversarial examples by mixing both explicit and implicit perturbations without using original ***,the proposed method can be applied to both white box and black box *** addition,in the inference stage,the adversarial examples can be generated without loading the original images into memory,which greatly reduces the memory *** compared DCVAE-adv with three most advanced adversarial attack algorithms:FGSM,AdvGAN,and AdvGAN++.The experimental results demonstrate that DCVAE-adv is superior to these state-of-the-art methods in terms of attack success rate and transfer ability for targeted *** code is available at https://***/xzforeverlove/DCVAE-adv.

关键词： deep neural network adversarial examples white box attack black box attack robustness

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Dynamic multifunctional metasurfaces:an inverse design deep learning approach

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Photonics Research 2024年第1期12卷 123-133页

作者： ZHI-DAN lei YI-DUO XU CHENG lei YAN ZHAO DU WANG The Institute of Technological Sciences Wuhan UniversityWuhan 430072China College of Materials Science and Engineering Sichuan UniversityChengdu 610065China

Optical metasurfaces(OMs)offer unprecedented control over electromagnetic waves,enabling advanced optical *** emergence of deep learning has opened new avenues for designing ***,existing deep learning methods for OMs primarily focus on forward design,which limits their design capabilities,lacks global optimization,and relies on prior ***,most OMs are static,with fixed functionalities once *** overcome these limitations,we propose an inverse design deep learning method for dynamic *** approach comprises a forward prediction network and an inverse retrieval *** forward prediction network establishes a mapping between meta-unit structure parameters and reflectance *** inverse retrieval network generates a library of meta-unit structure parameters based on target requirements,enabling end-to-end design of *** incorporating the dynamic tunability of the phase change material Sb2Te3with inverse design deep learning,we achieve the design and verification of dynamic multifunctional *** results demonstrate OMs with multiple information channels and encryption capabilities that can realize multiple physical field optical modulation *** Sb2Te3is in the amorphous state,near-field nano-printing based on meta-unit amplitude modulation is achieved for X-polarized incident light,while holographic imaging based on meta-unit phase modulation is realized for circularly polarized *** the crystalline state,the encrypted information remains secure even with the correct polarization input,achieving double *** research points towards ultra-compact,high-capacity,and highly secure information storage approaches.

关键词： polarization inverse approach

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Two-Stage Online Debiased Lasso Estimation and Inference for High-Dimensional Quantile Regression with Streaming Data

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Journal of Systems Science & Complexity 2024年第3期37卷 1251-1270页

作者： PENG Yanjin WANG lei School of Statistics and Data Science KLMDASRLEBPS and LPMCNankai UniversityTianjin 300071China

In this paper,the authors propose a two-stage online debiased lasso estimation and statistical inference method for high-dimensional quantile regression(QR)models in the presence of streaming *** the first stage,the authors modify the QR score function based on kernel smoothing and obtain the online lasso smoothed QR estimator through iterative *** estimation process only involves the current data batch and specific historical summary statistics,which perfectly accommodates to the special structure of streaming *** the second stage,an online debiasing procedure is carried out to eliminate biases caused by the lasso penalty as well as the accumulative approximation error so that the asymptotic normality of the resulting estimator can be *** authors conduct extensive numerical experiments to evaluate the performance of the proposed *** experiments demonstrate the effectiveness of the proposed method and support the theoretical *** application to the Beijing PM2.5 Dataset is also presented.

关键词： Adaptive tuning asymptotic normality debiased lasso online updating quantile regres-sion

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