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A systematic review of the inequality of health burdens related to climate change

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Frontiers of Environmental Science & engineering 2024年第5期18卷 137-153页

作者： Xinke Song Shihui Zhang Hai Huang Qun Ding Fang Guo Yaxin Zhang Jin Li Mingyu Li Wenjia Cai Can Wang State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing100084China Department of Earth system Science Tsinghua UniversityBeijing100084China

Climate change significantly impacts human health,exacerbating existing health inequalities and creating new *** study addresses the lack of systematic review in this area by analyzing 2440 publications,focusing on four key terms:health,disparities,environmental factors,and climate *** inclusion criteria limited the selection to English-language,peer-reviewed articles related to climate health hazards,ensuring the relevance and rigor of the synthesized *** process synthesized 65 relevant *** investigation revealed that recent research,predominantly from developed countries,has broadened its scope beyond temperature-related impacts to encompass diverse climate hazards,including droughts,extreme weather,floods,mental health issues,and the intersecting effects of Coronavirus Disease *** has highlighted exposure as the most studied element in the causal chain of climate change-related health inequalities,followed by adaptive capability and inherent *** most significant vulnerabilities were observed among populations with low socioeconomic status,ethnic minorities,and *** study further reveals research biases and methodological limitations,such as the paucity of attention to underdeveloped regions,a narrow focus on non-temperature-related hazards,challenges in attributing climate change effects,and a deficit of large-scale empirical *** findings call for more innovative research approaches and a holistic integration of physical,socio-political,and economic dimensions to enrich climate-health discourse and inform equitable policy-making.

关键词： Climate change Health impact Human well-being Inequality Vulnerability

Absolute pose estimation of UAV based on large-scale satellite image

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Chinese Journal of Aeronautics 2024年第6期37卷 219-231页

作者： Hanyu WANG Qiang SHEN Zilong DENG Xinyi CAO Xiaokang Wang School of Mechatronical engineering Beijing Institute of TechnologyBeijing 100081China beijing Institute of Technology Chongqing Innovation Center Chongqing 401120China

Obtaining absolute pose based on pre-loaded satellite images is one of the important means of autonomous navigation for small Unmanned Aerial Vehicles(UAVs)in Global Navigation Satellite system(GNSS)denied *** of the previous works have tended to build Convolutional Neural Networks(CNNs)to extract features and then directly regress the pose,which will fail when solving the challenges caused by the huge viewpoint and size differences between“UAV-satellite”image pairs in real-world ***,this paper proposes a probability distribution/regression integrated deep model with the attention-guided triple fusion mechanism,which estimates discrete distributions in pose space and three-dimensional vectors in translation *** order to overcome the shortage of the relevant dataset,this paper simulates image datasets captured by UAVs with forward-facing cameras during target searching and autonomous *** effectiveness,superiority,and robustness of the proposed method are verified by simulated datasets and flight tests.

关键词： Satellite imagery Unmanned Aerial Vehicle(UAV) Deep neural networks Vision navigation von Mises-Fisher distribution

Dual-assisted high-precision tracking technique for wideband multiplexed signals in new generation GNSS

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Satellite Navigation 2024年第1期5卷 52-73页

作者： Yunhan Qi Zheng Yao Mingquan Lu Department of Electronic engineering Tsinghua UniversityBeijing100084China beijing National Research Center for Information Science and Technology Beijing100084China

With the evolution of Global Navigation Satellite system(GNSS),new generation GNSS signals have adopted the dual-frequency multiplexing modulation techniques,which jointly modulate multiple signals located on multiple sub-frequencies into a Wideband Multiplexed Signal(WMS).Although WMSs were proposed initially to reduce the complexity of satellite transmitters and improve the transmission efficiency of signals,their multi-component structures and wide root mean square bandwidths introduced by high-frequency subcarriers also provide the possibility to improve the GNSS ranging ***,this paper proposes a Dual-assisted Multi-component Tracking(DMT)technique,which can not only fully use high-frequency subcarriers in WMSs,but also effectively track carrier,subcarrier,and code by jointly utilizing all components in *** this paper,the tracking and ranging performances of DMT are comprehensively analyzed theoretically and by simulation and real *** results show that compared with existing WMS tracking methods,DMT can achieve tracking results with lower tracking jitters and ranging results with higher precision,providing a highly advantageous solution for new generation GNSS signal processing.

关键词： Wideband multiplexed signal Dual-assisted Multi-component High precision tracking

Univariate Time Series Anomaly Detection Based on Hierarchical Attention Network

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Tsinghua Science and Technology 2024年第4期29卷 1181-1193页

作者： Zexi Chen Dongqiang Jia Yushu Sun Lin Yang Wenjie Jin Ruoxi Liu State Grid beijing Electric Power Company Beijing 100031China Institute of Electrical engineering Chinese Academy of SciencesBeijing 100190China

In order to support the perception and defense of the operation risk of the medium and low voltage distribution system, it is crucial to conduct data mining on the time series generated by the system to learn anomalous patterns, and carry out accurate and timely anomaly detection for timely discovery of anomalous conditions and early alerting. And edge computing has been widely used in the processing of Internet of Things (IoT) data. The key challenge of univariate time series anomaly detection is how to model complex nonlinear time dependence. However, most of the previous works only model the short-term time dependence, without considering the periodic long-term time dependence. Therefore, we propose a new Hierarchical Attention Network (HAN), which introduces seven day-level attention networks to capture fine-grained short-term time dependence, and uses a week-level attention network to model the periodic long-term time dependence. Then we combine the day-level feature learned by day-level attention network and week-level feature learned by week-level attention network to obtain the high-level time feature, according to which we can calculate the anomaly probability and further detect the anomaly. Extensive experiments on a public anomaly detection dataset, and deployment in a real-world medium and low voltage distribution system show the superiority of our proposed framework over state-of-the-arts.

关键词： edge computing anomaly detection univariate time series self-attention

Calculation method for the formation time of dynamic filter cake in slurry shield tunneling

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Frontiers of Structural and Civil engineering 2024年第9期18卷 1337-1349页

作者： Yinzun YANG Dajun YUAN Changyan DU Dalong JIN Jun HAO Key Laboratory of the Ministry of Education for Urban Underground engineering Beijing Jiaotong UniversityBeijing 100044China School of Civil engineering Beijing Jiaotong UniversityBeijing 100044China China Railway 14th Bureau Group Mega Shield engineering Co. Ltd.Nanjing 211800China

In slurry shield tunneling,the stability of tunnel face is closely related to the filter *** cutting of the cutterhead has negative impact on the formation of filter *** study focuses on the formation time of dynamic filter cake considering the filtration effect and rotation of *** effect is the key factor for slurry infiltration.A multilayer slurry infiltration experiment system is designed to investigate the variation of filtrate rheological property in infiltration *** mass concentration C_(L),soil permeability coefficient k,the particle diameter ratio between soil equivalent grain size and representative diameter of slurry particles d_(10)/D_(85) are selected as independent design variables to fit the computational formula of filtration *** on the relative relation between the mass of deposited particles in soil pores and infiltration time,a mathematical model for calculating the formation time of dynamic filter cake is proposed by combining the formation criteria and formation rate of external filter *** accuracy of the proposed model is verified through existing experiment *** results show that filtration coefficient is positively correlated with slurry mass concentration,while negatively correlated with the soil permeability coefficient and the particle diameter ratio between soil and *** infiltration distance increases,the adsorption capacity of soil skeleton to slurry particles gradually *** formation time of external filter cake is significantly lower than internal filter cake and the ratio is approximately *** the dynamic cutting of the cutterhead,the formation time is positively associated with the rotation speed of cutter head,while negatively with the phase angle difference between adjacent cutter *** formation rate of external filter cake is greater than 98%when d_(10)/D_(85)≤*** increasing the content or decreasing the diameter size of solid-phase

关键词： slurry infiltration filtration coefficient dynamic filter cake formation time rotation speed phase angle

Frequency and Reliability Analysis of Load-Bearing Composite Beams

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Automotive Innovation 2024年第1期7卷 194-207页

作者： Junlei Wei Lingyu Sun Xinli Gao Wenfeng Pan Jiaxin Wang Jinxi Wang School of Transportation Science and engineering Beihang University37 Xueyuan RoadHaidian DistrictBeijing 100191China beijing Key Laboratory for High-Efficient Power Transmission and system Control of New Energy Resource Vehicle Beihang University37 Xueyuan RoadHaidian DistrictBeijing 100191China beijing Hangshu Vehicle Data Research Institute Co. Ltd.Beijing 100062China

The increasing utilization of fiber-reinforced thermoplastics(FRTPs)as a substitute for metal in load-bearing structures poses challenges related to NVH issues arising from frequency variations and reliability concerns stemming from fiber dispersion within the resin *** this study,the steel automobile seat beam serves as a benchmark for *** beams are designed and fabricated using two distinct processes:compression molding and injection ***,their modal frequency and reliability are meticulously *** investigations are conducted to explore the influence of various factors,including the combination of laminates and ribs,as well as the stacking sequence of laminates,on the modal *** findings reveal that the modal frequency and vibration mode are subject to alterations based on the fiber type,beam material,and laminate stacking ***,in comparison to the steel benchmark,the first-order frequency of the FRTP beam in this study experiences a 6.59%increase while simultaneously achieving a weight reduction of 32.42%.To assess reliability,a comprehensive analysis is performed,considering a six-fold standard *** analysis yields the permissible range of fluctuation for material elastic constants,bending performance,and frequency ***,the FRTP beams meet the required reliability *** results provide valuable insights for comprehending the stiffness-dependent response and effectively controlling structural performance when implementing FRTP for weight reduction purposes.

关键词： Automobile Fiber-reinforced thermoplastics Lightweight design Frequency change Reliability analysis

New method for multibody dynamics based on unknown constraint force

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Science China(Technological Sciences) 2024年第3期67卷 791-808页

作者： TIAN Ying JIA YingHong ZHANG Jun School of Astronautics Beihang UniversityBeijing 100191China beijing Institute of Control engineering Beijing 100190China National Laboratory of Space Intelligent Control Beijing 100190China

This paper presents a new method for the dynamics of multibody systems based on unknown constraint force. The method can uniformly solve multibody systems with typical configurations, including the system with rigid-flexible coupling, the system in tree topology, and the system with loop constraints. Unlike common methods, the proposed method can model the loop system without “cutting off” loop constraints, leading to the exact same modelling process as the tree-like system performs. Based on graph theory, a topological record matrix M_(rec) is proposed to capture the arbitrary system configuration. Moreover, constraint forces are selected as the key variables in semi-recursive framework. With the recursive kinematics relationship between adjacent bodies, the constraint force equation is further assembled to achieve the full-state system solution. The numerical simulations demonstrate the accuracy of the proposed method.

关键词： multibody system dynamic modelling rigid-flexible coupling unknown constraint force graph theory semi-recursive algorithm

Pore-pressure and stress-coupled creep behavior in deep coal:Insights from real-time NMR analysis

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International Journal of Mining Science and Technology 2024年第1期34卷 77-90页

作者： Wenhao Jia Hongwei Zhou Senlin Xie Yimeng Wang Xinfeng Hu Lei Zhang School of Mechanics and Civil engineering China University of Mining and Technology-BeijingBeijing 100083China School of Energy and Mining engineering China University of Mining and Technology-BeijingBeijing 100083China State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology-BeijingBeijing 100083China College of Safety and Emergency Management engineering Taiyuan University of TechnologyTaiyuan 030024China

Understanding the variations in microscopic pore-fracture structures(MPFS) during coal creep under pore pressure and stress coupling is crucial for coal mining and effective gas treatment. In this manuscript, a triaxial creep test on deep coal at various pore pressures using a test system that combines in-situ mechanical loading with real-time nuclear magnetic resonance(NMR) detection was ***-scale quantitative characterization, online real-time detection, and visualization of MPFS during coal creep influenced by pore pressure and stress coupling were performed using NMR and NMR imaging(NMRI) techniques. The results revealed that seepage pores and microfractures(SPM) undergo the most significant changes during coal creep, with creep failure gradually expanding from dense primary pore fractures. Pore pressure presence promotes MPFS development primarily by inhibiting SPM compression and encouraging adsorption pores(AP) to evolve into SPM. Coal enters the accelerated creep stage earlier at lower stress levels, resulting in more pronounced creep deformation. The connection between the micro and macro values was established, demonstrating that increased porosity at different pore pressures leads to a negative exponential decay of the viscosity coefficient. The Newton dashpot in the ideal viscoplastic body and the Burgers model was improved using NMR experimental results, and a creep model that considers pore pressure and stress coupling using variable-order fractional operators was developed. The model’s reasonableness was confirmed using creep experimental data. The damagestate adjustment factors ω and β were identified through a parameter sensitivity analysis to characterize the effect of pore pressure and stress coupling on the creep damage characteristics(size and degree of difficulty) of coal.

关键词： Real-time monitoring Pore pressure-stress coupling Microscopic pore-fracture structure Variable-order fractional creep model Deep coal

Carbon uptake by cement in China:Estimation and contribution to carbon neutrality goals

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Science China Earth Sciences 2024年第6期67卷 2056-2067页

作者： Mingjing MA Zi HUANG Jiaoyue WANG Le NIU Wenfeng ZHANG Xiaowei XU Fengming XI Zhu LIU Institute of Applied Ecology Chinese Academy of SciencesShenyang 110016China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Department of Earth system Science Tsinghua UniversityBeijing 100084China Department of engineering Science University of OxfordOxfordOX13UK

Cement is a widely used construction material *** manufacturing contributes to anthropogenic CO_(2)emissions ***,its alkaline compounds can absorb CO_(2)from the surrounding environment and engage in a carbonation reaction,thereby functioning as a carbon *** a major cement producer and consumer,China has an important responsibility to rigorously investigate and accurately account for cement carbon *** study presents a comprehensive analytical model of cement carbon uptake from China,revealing a substantial increase in carbon uptake from 1930 to 2021,peaking at 426.77 Mt CO_(2)(95% Confidence Interval:317.67-874.33 Mt CO_(2))in *** uptake accounts for 8.10% to 45.40% of China’s annual land sink and 2.51% to 4.54% of the global land *** cumulative carbon uptake by cement is approximately 7.06 Gt CO_(2)(95%CI:5.22–9.44 Gt CO_(2))during this period,offsetting 50.7% of the total emissions(13.91 Gt CO_(2),95%CI:12.44–17.00 Gt CO_(2))from the cement ***,cement mortar contributed to most absorption(65.64%).From a life cycle perspective,the service stage of cement materials is the period where the largest CO_(2)sink is formed,accounting for 90.03% of the ***,the potential for carbon sequestration in cement materials and their waste is ***,the model improves the accuracy of cement carbon accounting,supporting both China and global carbon neutrality ***,it is crucial for China to achieve its carbon neutrality goals sooner by prioritizing the environmental benefits of cement materials and wastes,and accelerating the development and commercialization of CO_(2)sequestration technologies for cement and its by-products.

关键词： Cement Carbon uptake Life cycle assessment Carbon emission reduction Carbon neutrality