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Dynamic COVID Zero Strategy triggered a significant increase of chlorine-based disinfectant

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Frontiers of Environmental Science & Engineering 2024年第8期18卷 73-80页

作者： Xuhao Wang Mai Su Chunyan Wang Yi Liu school of Environment Tsinghua UniversityBeijing 100084China

Chlorine-based disinfectants(CBDs)have been widely used to prevent and control the spread of the COVID-19,which may lead to the formation of carcinogenic *** China,strict disinfection strategies by local governments/communities or volunteering by residents have been implemented to meet the Dynamic COVID Zero(DCZ)***,the amount of CBDs used has not been *** author proposed an urban-scale disinfectant consumption estimation(ALICE)model to quantify weekly CBD *** results show that the CBD consumption for the urban region of beijing during the DCZ strategy was 3704.0 t(0.43 kg/(cap-yr)),equivalent to a monthly increase of 15 g/cap(70.5%)in CBD consumption compared with that in *** to the scenario analysis,a stricter strategy with a shorter response time toward new cases will decrease the total CBD consumption by 1.2% compared with the baseline estimation.A more precise prevention strategy with a smaller delineation of risk area and a less stringent strategy with a longer response time will lower the total CBD consumption by 0.42% and 0.35%,***,the more precise prevention strategy will reduce CBD consumption of close off and lockdown area(COLD area)by 16.9%,and the stricter strategy will reduce this consumption by 37.7%.This study highlights the impact of pandemic prevention and control strategies on chlorine-based disinfectant consumption and some implications for future environmental pollution and risk assessments.

关键词： COVID-19 Dynamic COVID Zero Strategy Disinfectants consumption Bottom-up approach Scenario analysis

Process optimization and mechanism study of ionic liquid-based mixed amine biphasic solvents for CO_(2) capture in biogas upgrading procedure

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Frontiers of Environmental Science & Engineering 2024年第8期18卷 43-57页

作者： Fanzhi Meng Siyu Han Li Lin Jinglin Li Kailun Chen Jianguo Jiang school of Environment Tsinghua UniversityBeijing 100084China

This study focused on enhancing the efficiency of methane upgrading and reducing energy consumption in the biogas upgrading process through the use of biphasic *** aqueous-based biphasic solvent,comprising methyl monoethanolamine(MMEA),N-methyldiethanolamine(MDEA),and 1-butyl-3-methylimidazolium tetrafluoroborate(ItFB),was meticulously *** biogas upgrading effect,regeneration efficiency,regeneration energy consumption,economic viability,selectivity,and phase separation characteristics of this absorbent were systematically *** parameters,including different inlet flow rates,stirring rate,methane inlet concentrations,reaction temperatures,and amine mixing ratios,were adjusted to investigate their impact.A comprehensive evaluation was conducted on the biogas upgrading effect and substance migration trends of the biphasic *** process parameters were determined,demonstrating the favorable impact of the biphasic solvent on biogas *** upgraded gas achieved a methane purity exceeding 96%,and the regeneration energy consumption decreased by 44.27% compared to 30 wt.%MEA,resulting in a more than 50% improvement in economic *** interaction between the ionic liquid and carbamate facilitated the phase separation process,with carbon enrichment after separation exceeding 95%.This enhancement significantly contributed to the improvement of regeneration energy *** study thus concludes that biphasic solvents,exemplified by the described aqueous-based solution,offer a promising avenue for effective biogas upgrading with notable advancements in economic and energy efficiency.

关键词： Biphasic solvents Biogas upgrading Energy consumption Process parameters Ionic liquid

Mechanism of internal thermal runaway propagation in blade batteries

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Journal of Energy Chemistry 2024年第2期89卷 184-194,I0005页

作者： Xuning Feng Fangshu Zhang Wensheng Huang Yong Peng Chengshan Xu Minggao Ouyang school of Vehicle and Mobility Tsinghua UniversityBeijing 100084China

Blade batteries are extensively used in electric vehicles,but unavoidable thermal runaway is an inherent threat to their safe *** study experimentally investigated the mechanism underlying thermal runaway propagation within a blade battery by using a nail to trigger thermal runaway and thermocouples to track its propagation inside a *** results showed that the internal thermal runaway could propagate for up to 272 s,which is comparable to that of a traditional battery *** velocity of the thermal runaway propagation fluctuated between 1 and 8 mm s^(-1),depending on both the electrolyte content and high-temperature gas *** the early stages of thermal runaway,the electrolyte participated in the reaction,which intensified the thermal runaway and accelerated its *** the battery temperature increased,the electrolyte evaporated,which attenuated the acceleration *** diffusion affected thermal runaway propagation through both heat transfer and mass *** experimental results indicated that gas diffusion accelerated the velocity of thermal runaway propagation by 36.84%.We used a 1D mathematical model and confirmed that convective heat transfer induced by gas diffusion increased the velocity of thermal runaway propagation by 5.46%-17.06%.Finally,the temperature rate curve was analyzed,and a three-stage mechanism for internal thermal runaway propagation was *** Stage I,convective heat transfer from electrolyte evaporation locally increased the temperature to 100℃.In Stage II,solid heat transfer locally increases the temperature to trigger thermal *** StageⅢ,thermal runaway sharply increases the local *** proposed mechanism sheds light on the internal thermal runaway propagation of blade batteries and offers valuable insights into safety considerations for future design.

关键词： Lithium-ion battery Blade battery Thermal runaway Internal thermal runaway propagation

A CAD-BEM geometry transformation method for face-based primary geometric input based on closed contour recognition

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Building Simulation 2024年第2期17卷 335-354页

作者： Jun Xiao Hao Zhou Shiji Yang Deyin Zhang Borong Lin Department of Building Science School of ArchitectureTsinghua UniversityBeijing100084China Key Laboratory of Eco Planning&Green Building Ministry of EducationTsinghua UniversityBeijing100084China Institute for Urban Governance and Sustainable Development Tsinghua UniversityBeijing100084China

Performance analysis during the early design stage can significantly reduce building energy ***,it is difficult to transform computer-aided design(CAD)models into building energy models(BEM)to optimize building *** model structures for CAD and BEM are *** this study,geometry transformation methods was implemented in BES tools for the early design stage,including auto space generation(ASG)method based on closed contour recognition(CCR)and space boundary topology calculation *** program is developed based on modeling tools SketchUp to support the CAD format(like*.stl,*.dwg,*.ifc,etc.).It transforms face-based geometric information into a zone-based tree structure model that meets the geometric requirements of a single-zone BES combined with the other thermal parameter inputs of the *** addition,this study provided a space topology calculation method based on a single-zone BEM *** program was developed based on the SketchUp modeling tool to support additional CAD formats(such as*.stl,*.dwg,*.ifc),which can then be imported and transformed into*.*** to current methods mostly focused on BIM-BEM transformation,this method can ensure more modeling *** method was integrated into a performance analysis tool termed MOOSAS and compared with the current version of the transformation *** were tested on a dataset comprising 36 conceptual models without partitions and six real cases with detailed *** ensures a transformation rate of two times in any bad model condition and costs only 1/5 of the time required to calculate each room compared to the previous version.

关键词： geometry transformation building energy model computer aid design closed contour recognition

Research on General-Purpose Brain-Inspired Computing Systems

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Journal of Computer Science & Technology 2024年第1期39卷 4-21页

作者：渠鹏纪兴龙陈嘉杰庞猛李宇晨刘晓义张悠慧 Department of Computer Science and Technology Tsinghua UniversityBeijing 100084China Department of Precision Instrument Tsinghua UniversityBeijing 100084China

Brain-inspired computing is a new technology that draws on the principles of brain science and is oriented to the efficient development of artificial general intelligence(AGI),and a brain-inspired computing system is a hierarchical system composed of neuromorphic chips,basic software and hardware,and algorithms/applications that embody this *** the system is developing rapidly,it faces various challenges and opportunities brought by interdisciplinary research,including the issue of software and hardware *** paper analyzes the status quo of brain-inspired computing *** by some design principle and methodology of general-purpose computers,it is proposed to construct"general-purpose"brain-inspired computing systems.A general-purpose brain-inspired computing system refers to a brain-inspired computing hierarchy constructed based on the design philosophy of decoupling software and hardware,which can flexibly support various brain-inspired computing applications and neuromorphic chips with different ***,this paper introduces our recent work in these aspects,including the ANN(artificial neural network)/SNN(spiking neural network)development tools,the hardware agnostic compilation infrastructure,and the chip micro-archi-tecture with high flexibility of programming and high performance;these studies show that the"general-purpose"system can remarkably improve the efficiency of application development and enhance the productivity of basic software,thereby being conductive to accelerating the advancement of various brain-inspired algorithms and *** believe that this is the key to the collaborative research and development,and the evolution of applications,basic software and chips in this field,and conducive to building a favorable software/hardware ecosystem of brain-inspired computing.

关键词： brain-inspired computing neuromorphic chip compiler spiking neural network

IoTDQ: An Industrial IoT Data Analysis Library for Apache IoTDB

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Big Data Mining and Analytics 2024年第1期7卷 29-41页

作者： Pengyu Chen Wendi He Wenxuan Ma Xiangdong Huang Chen Wang school of Software Tsinghua UniversityBeijing 100084China National Engineering Research Center for Big Data Software(NERCBDS) Tsinghua UniversityBeijing 100084China

There is a growing demand for time series data analysis in industry *** loTDB is a time series database designed for the Internet of Things(loT)with enhanced storage and I/O *** User-Defined Functions(UDF)provided,computation for time series can be executed on Apache loTDB *** satisfy most of the common requirements in industrial time series analysis,we create a UDF library,loTDQ,on Apache *** library integrates stream computation functions on data quality analysis,data profiling,anomaly detection,data repairing,*** enables users to conduct a wide range of analyses,such as monitoring,error diagnosis,equipment reliability *** provides a framework for users to examine loT time series with data quality *** show that loTDQ keeps the same level of performance compared to mainstream alternatives,and shortens I/O consumption for Apache loTDB users.

关键词： industrial big data data quality data mining and analytics

Potential effects of automated driving on vehicle travel demand: A comparison of three case cities

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第2期11卷 348-361页

作者： Jingchen Dai Ruimin Li Zhiyong Liu school of Civil Engineering Tsinghua UniversityBeijing 100084China Hang Lung Center for Real Estate Tsinghua UniversityBeijing 100084China school of Traffic and Transportation Beijing Jiaotong UniversityBeijing 100044China

Automated vehicles(AVs)hold the potential to reduce road accidents,mitigate traffic congestion,and improve travel ***,the possible countervailing impacts from the changes in underserved populations’vehicle travel demand tend to be *** determine the vehicle travel demand changes that resulted from underserved populations aged between 6 and 80,this paper explores the latent effect of AVs on vehicle kilometers traveled(VKT)in a fully AV environment using person trip survey data from the cities of Sanya,Shijiazhuang,and Shenzhen in *** paper uses the natural decline hypothesis of travel demand and proposes a regression model to investigate the difference among the cities’latent vehicle travel *** show that the average VKT of the overall population in Sanya,Shijiazhuang,and Shenzhen increased by 33.4%,47.0%,and46.8%,*** analysis of the regression model confirms that the current travel behavior of individuals can affect the degree of increase in their average *** AVs into public transport,increasing the acceptance of automated shared mobility options,transforming road space use type,and prototyping AV designs with various features and needs are potential methods to cope with the countervailing *** total VKT of the overall population increased by approximately 10%-25%depending on the *** conclusions of this paper provide informative insights into the evaluation of VKT for underserved populations and contribute to the deployment of AVs to address equity and inclusion issues.

关键词： Automated vehicles Vehicle kilometers traveled Aging population Travel behavior Natural decline hypothesis

Foundation models meet visualizations: Challenges and opportunities

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Computational Visual Media 2024年第3期10卷 399-424页

作者： Weikai Yang Mengchen Liu Zheng Wang Shixia Liu school of Software Tsinghua UniversityBeijing 100084China Microsoft Redmond 98052USA

Recent studies have indicated that foundation models, such as BERT and GPT, excel atadapting to various downstream tasks. This adaptability has made them a dominant force in buildingartificial intelligence (AI) systems. Moreover, a newresearch paradigm has emerged as visualizationtechniques are incorporated into these models. Thisstudy divides these intersections into two researchareas: visualization for foundation model (VIS4FM)and foundation model for visualization (FM4VIS).In terms of VIS4FM, we explore the primary roleof visualizations in understanding, refining, and evaluating these intricate foundation models. VIS4FMaddresses the pressing need for transparency, explainability, fairness, and robustness. Conversely, in termsof FM4VIS, we highlight how foundation models canbe used to advance the visualization field itself. Theintersection of foundation models with visualizations ispromising but also introduces a set of challenges. Byhighlighting these challenges and promising opportunities, this study aims to provide a starting point forthe continued exploration of this research avenue.

关键词： visualization artificial intelligence(AI) machine learning foundation models visualization for foundation model(VIS4FM) foundation model for visualization(FM4VIS)

Super-resolution diffractive neural network for alloptical direction of arrival estimation beyond diffraction limits

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Light(Science & Applications) 2024年第8期13卷 1602-1614页

作者： Sheng Gao Hang Chen Yichen Wang Zhengyang Duan Haiou Zhang Zhi Sun Yuan Shen Xing Lin Department of Electronic Engineering Tsinghua UniversityBeijing 100084China beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China

Wireless sensing of the wave propagation direction from radio sources lays the foundation for communication,radar,navigation,***,the existing signal processing paradigm for the direction of arrival estimation requires the radio frequency electronic circuit to demodulate and sample the multichannel baseband signals followed by a complicated computing process,which places the fundamental limit on its sensing speed and energy ***,we propose the super-resolution diffractive neural networks(S-DNN)to process electromagnetic(EM)waves directly for the DOA estimation at the speed of *** multilayer meta-structures of S-DNN generate super-oscillatory angular responses in local angular regions that can perform the all-optical DOA estimation with angular resolutions beyond the diffraction *** spatial-temporal multiplexing of passive and reconfigurable S-DNNs is utilized to achieve high-resolution DOA estimation over a wide field of *** S-DNN is validated for the DOA estimation of multiple radio sources over 5 GHz frequency bandwidth with estimation latency over two to four orders of magnitude lower than the state-of-the-art commercial devices in *** results achieve the angular resolution over an order of magnitude,experimentally demonstrated with four times,higher than diffraction-limited *** also apply S-DNN’s edge computing capability,assisted by reconfigurable intelligent surfaces,for extremely low-latency integrated sensing and communication with low power *** work is a significant step towards utilizing photonic computing processors to facilitate various wireless sensing and communication tasks with advantages in both computing paradigms and performance over electronic computing.

关键词： beyond optical network