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Impact of COVID-19 on the energy consumption of commercial buildings:A case study in Singapore

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Energy and Built Environment 2024年第3期5卷 364-373页

作者： Senhong cai Zhonghua Gou School of Urban Design Wuhan UniversityWuhanChina

Numerous studies have demonstrated that commercial activities have significantly reduced during COVID-19,while there are few studies disclosing the consequent impacts on the energy consumption of commercial *** study explores the changes in energy consumption of different types of commercial buildings in Sin-gapore under the impact of the pandemic,using commercial building energy performance data from 2017 to 2020(n=540).The sampled buildings include 93 hotel buildings,303 office buildings,106 retail buildings,and 38 mixed *** analysis mainly used linear regression and paired sample *** results showed that relative to 2019,the mean energy use intensity(EUI)of sampled commercial buildings decreased by 56.77 kWh/m^(2)in the pandemic year(2020),a plunge of 19.9%.The extent to which the EUI of each type of commercial building is affected by the pandemic is found as:mixed development>retail>office>*** study also identi-fied the factors that significantly influenced the EUI of commercial buildings before and during the *** results of the study complement existing knowledge about the factors influencing energy consumption in com-mercial buildings by considering the impact of the pandemic and furthermore contribute to the improvement of energy management in commercial buildings by providing directions for building energy efficiency approaches.

关键词： Commercial buildings Energy consumption Energy use intensity Impact of COVID-19 Influential factors

A reduced-order model for fast predicting ionized flows of hypersonic vehicles along flight trajectory

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Chinese Journal of Aeronautics 2024年第1期37卷 89-105页

作者： Jingchao ZHANG Chunsheng NIE Jinsheng cai Shucheng PAN School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Science and Technology on Space Physics Laboratory China Academy of Launch Vehicle TechnologyBeijing 100076China Institute of Extreme Mechanics Northwestern Polytechnical UniversityXi’an 710072China

An improved Reduced-Order Model(ROM)is proposed based on a flow-solution preprocessing operation and a fast sampling strategy to efficiently and accurately predict ionized hypersonic *** ROM is generated in low-dimensional space by performing the Proper Orthogonal Decomposition(POD)on snapshots and is coupled with the Radial Basis Function(RBF)to achieve fast prediction ***,due to the disparate scales in the ionized flow field,the conventional ROM usually generates spurious negative ***,this issue is addressed by performing flow-solution preprocessing in logarithmic space to improve the conventional ***,extra orthogonal polynomials are introduced in the RBF interpolation to achieve additional improvement of the prediction *** addition,to construct high-efficiency snapshots,a trajectory-constrained adaptive sampling strategy based on convex hull optimization is *** evaluate the performance of the proposed fast prediction method,two hypersonic vehicles with classic configurations,i.e.a wave-rider and a reentry capsule,are used to validate the proposed *** two cases show that the proposed fast prediction method has high accuracy near the vehicle surface and the free-stream region where the flow field is *** with the conventional ROM prediction,the prediction results are significantly improved by the proposed method around the discontinuities,*** shock wave and the ionized *** a result,the proposed fast prediction method reduces the error of the conventional ROM by at least 45%,with a speedup of approximately 2.0×105compared to the Computational Fluid Dynamic(CFD)*** test cases demonstrate that the method developed here is efficient and accurate for predicting ionized hypersonic flows.

关键词： Reduced-order model Radial basis function Constrained sampling Transfer function Fast flow prediction Ionized hypersonic flows

Disentangling distinct Cu surface sites for electrocatalytic CO_(2)-to-CO and CO-to-C_(2+)conversion

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Science China Chemistry 2024年第4期67卷 1047-1048页

作者： Kun Jiang Wen-Bin cai Interdisciplinary Science Research Centre School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Collaborative Innovation Center of Chemistry for Energy MaterialsDepartment of ChemistryFudan UniversityShanghai 200438China

Electrochemical CO_(2)reduction reaction(CO_(2)RR)is a promising strategy to curb anthropogenic carbon emissions,for which intermittent renewable electricity could be stored as chemical energy within carbon-based fuel... 详细信息

关键词： carbon Electrochemical surface

Doped holographic superconductors in the Gubser–Rocha model

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Communications in Theoretical Physics 2024年第4期76卷 80-92页

作者： Ziyi Zhao Wenhe cai Shuta Ishigaki Department of Physics Shanghai UniversityShanghai 200444China Shanghai Key Laboratory of High Temperature Superconductors Department of PhysicsShanghai UniversityShanghai 200444China

We construct a doped holographic superconductor in the Gubser–Rocha model,and realize a superconducting dome in the middle of the temperature-doping phase *** is worth noting that unlike in previous research,the profile of our dome shrinks inward near to zero *** the numerical observation for the coupling dependence of the phase diagram,we find that the coupling between the two gauge fields plays a crucial role in the formation of the *** also analytically calculate the DC conductivity of the normal phase of the system in the momentum dissipation and obtain resistivity which is proportional to the *** AC conductivity is calculated numerically.

关键词： AdS-CFT correspondence High-Tc superconductor AC/DC conductivities Gubser-Rocha geometry

Induced pluripotent stem cells(iPSCs):molecular mechanisms of induction and applications

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Signal Transduction and Targeted Therapy 2024年第5期9卷 2065-2090页

作者： Jonas Cerneckis Hongxia cai Yanhong Shi Department of Neurodegenerative Diseases Beckman Research Institute of City of HopeDuarteCA 91010USA Irell&Manella Graduate School of Biological Sciences Beckman Research Institute of City of HopeDuarteCA 91010USA

The induced pluripotent stem cell(iPSC)technology has transformed in vitro research and holds great promise to advance regenerative *** have the capacity for an almost unlimited expansion,are amenable to genetic engineering,and can be differentiated into most somatic cell *** have been widely applied to model human development and diseases,perform drug screening,and develop cell *** this review,we outline key developments in the iPSC field and highlight the immense versatility of the iPSC technology for in vitro modeling and therapeutic *** begin by discussing the pivotal discoveries that revealed the potential of a somatic cell nucleus for reprogramming and led to successful generation of *** consider the molecular mechanisms and dynamics of somatic cell reprogramming as well as the numerous methods available to induce ***,we discuss various iPSC-based cellular models,from mono-cultures of a single cell type to complex three-dimensional organoids,and how these models can be applied to elucidate the mechanisms of human development and *** use examples of neurological disorders,coronavirus disease 2019(COVID-19),and cancer to highlight the diversity of disease-specific phenotypes that can be modeled using iPSC-derived *** also consider how iPSC-derived cellular models can be used in high-throughput drug screening and drug toxicity ***,we discuss the process of developing autologous and allogeneic iPSC-based cell therapies and their potential to alleviate human diseases.

关键词： mechanisms programming holds

Study on the evolution of solid–liquid–gas in multi-scale pore methane in tectonic coal

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Chinese Journal of Chemical Engineering 2024年第7期71卷 122-131页

作者： Junjie cai Xijian Li Hao Sui Honggao Xie College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China Mining College Guizhou UniversityGuiyang 550025China

The rich accumulation of methane(CH_(4))in tectonic coal layers poses a significant obstacle to the safe and efficient extraction of coal seams and coalbed *** coal samples from three geologically complex regions were selected,and the main results obtained by using a variety of research tools,such as physical tests,theoretical analyses,and numerical simulations,are as follows:22.4–62.5 nm is the joint segment of pore volume,and 26.7–100.7 nm is the joint segment of pore specific surface *** the dynamic gas production process of tectonic coal pore structure,the adsorption method of methane molecules is“solid–liquid adsorption is the mainstay,and solid–gas adsorption coexists”.Methane stored in micropores with a pore size smaller than the jointed range is defined as solid-state *** within the jointed range,which transition from micropore filling to surface adsorption,are defined as gaseous *** outside the jointed range,where solid–liquid adsorption occurs,are defined as liquid *** evolution of pore structure affects the methane adsorption mode,which provides basic theoretical guidance for the development of coal seam resources.

关键词： Tectonic coal Multiscale pore structure Methane adsorption Micropore filling Monolayer Molecular simulation

Practical cloud storage auditing using serverless computing

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Science China(Information Sciences) 2024年第3期67卷 33-47页

作者： Fei CHEN Jianquan cai Tao XIANG Xiaofeng LIAO College of Computer Science and Software Engineering Shenzhen University College of Computer Science Chongqing University

Cloud storage auditing research is dedicated to solving the data integrity problem of outsourced storage on the cloud. In recent years, researchers have proposed various cloud storage auditing schemes using different techniques. While these studies are elegant in theory, they assume an ideal cloud storage model;that is, they assume that the cloud provides the storage and compute interfaces as required by the proposed schemes. However, this does not hold for mainstream cloud storage systems because these systems only provide read and write interfaces but not the compute interface. To bridge this gap, this work proposes a serverless computing-based cloud storage auditing system for existing mainstream cloud object storage. The proposed system leverages existing cloud storage auditing schemes as a basic building block and makes two adaptations. One is that we use the read interface of cloud object storage to support block data requests in a traditional cloud storage auditing scheme. Another is that we employ the serverless computing paradigm to support block data computation as traditionally required. Leveraging the characteristics of serverless computing, the proposed system realizes economical, pay-as-you-go cloud storage auditing. The proposed system also supports mainstream cloud storage upper layer applications(e.g., file preview) by not modifying the data formats when embedding authentication tags for later auditing. We prototyped and open-sourced the proposed system to a mainstream cloud service, i.e., Tencent Cloud. Experimental results show that the proposed system is efficient and promising for practical use. For 40 GB of data, auditing takes approximately 98 s using serverless computation. The economic cost is 120.48 CNY per year, of which serverless computing only accounts for 46%. In contrast, no existing studies reported cloud storage auditing results for real-world cloud services.

关键词： cloud storage auditing serverless computing object storage usability

Interplay between Microscopic Structures and Macroscopic Viscoelastic Properties of Polyampholyte Gels

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Chinese Journal of Polymer Science 2024年第9期42卷 1360-1367,I0008页

作者： You-cai Xue Yi-Ming Yang Di Jia Beijing National Laboratory for Molecular Sciences Laboratory of Polymer Physics and ChemistryInstitute of ChemistryChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China

Polyampholyte gels,which have hierarchical structures,exhibit excellent self-healing properties and have great promise for biomaterials and *** investigated the relationship between microscopic structures and macroscopic viscoelastic properties of polyampholyte gels and found three factors influencing their viscoelastic properties,including the chemical crosslinking bonds,topological entanglements controlled by monomer concentration,and the ionic *** strength plays a major role on the strength of ionic bonds.A crossover point of elastic modulus and loss modulus was observed in the dynamic frequency sweeps at low monomer concentration or low chemical crosslinking density for gels with intermediate strength of ionic *** solid-liquid transition signaled by the crossover point is a typical feature of dynamic associated gels,representing the dynamical association-dissociation of the ionic bonds and full relaxation of the topological entanglements in the gel *** the crossover point disappears when the ionic bonds are too weak or too strong to form“permanent”***,in the non-linear yielding measurement,gels with intermediate strength of the ionic bonds are ductile and yield at very large shear strain due to the self-healing properties and the dynamic association-dissociation of the ionic *** the self-healing properties disappear when the ionic bond strength is too weak or too *** work reveals the mechanism of how the dynamic association-dissociation of ionic bonds influences both the linear and non-linear viscoelastic properties of the polyampholyte gels.

关键词： Polyampholyte gel Ionic bond Topological entanglement Self-healing Hierarchical structure

Few-Shot Graph Classification with Structural-Enhanced Contrastive Learning for Graph Data Copyright Protection

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Tsinghua Science and Technology 2024年第2期29卷 605-616页

作者： Kainan Zhang DongMyung Shin Daehee Seo Zhipeng cai Department of Computer Science Georgia State UniversityAtlantaGA 30303USA LSWare Inc. Seoul 08504Republic of Korea College of Intelligence Information Engineering Sangmyung UniversitySeoul 03016Republic of Korea

Open-source licenses can promote the development of machine learning by allowing others to access,modify,and redistribute the training ***,not all open-source licenses may be appropriate for data sharing,as some may not provide adequate protections for sensitive or personal information such as social network ***,some data may be subject to legal or regulatory restrictions that limit its sharing,regardless of the licensing model ***,obtaining large amounts of labeled data can be difficult,time-consuming,or expensive in many real-world ***-shot graph classification,as one application of meta-learning in supervised graph learning,aims to classify unseen graph types by only using a small amount of labeled ***,the current graph neural network methods lack full usage of graph structures on molecular graphs and social network *** structural features are known to correlate with molecular properties in chemistry,structure information tends to be ignored with sufficient property information ***,the common binary classification task of chemical compounds is unsuitable in the few-shot setting requiring novel ***,this paper focuses on the graph classification tasks of a social network,whose complex topology has an uncertain relationship with its nodes'*** two multi-class graph datasets with large node-attribute dimensions constructed to facilitate the research,we propose a novel learning framework that integrates both meta-learning and contrastive learning to enhance the utilization of graph topological *** experiments demonstrate the competitive performance of our framework respective to other state-of-the-art methods.

关键词： few-shot learning contrastive learning data copyright protection