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A Novel Bus Differential Protection Method Based on the Frequency-Dependent Evolution Mechanism of Fault-Current Traveling Waves

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IEEE Sensors Journal 2025年第10期25卷 18344-18357页

作者： Yu, Kun Zeng, Jupeng Zeng, Xiangjun Liu, Feng She, Xiaolong Wang, Sheng Zhuo, Chao State Key Laboratory of Disaster Prevention & Reduction for Power Grid Changsha University of Science and Technology Changsha410114 China

The time-domain fault signal data window provided by the new energy source is short. Certain existing bus protection methods may operate incorrectly when there are loud noise interference and high-resistance fault. Here, a novel differential bus protection method is proposed by using the fault-current traveling wave (FCTW) frequency domain. Changes in the reflection coefficient and the refraction coefficient with respect to the frequency of FCTWs (when they are reflected to the fault line and refracted to the nonfault line through the bus) are theoretically deduced. The frequency-dependent evolution mechanism of FCTWs on buses and transmission lines is revealed. Characteristic differences in the FCTW spectrum waveforms that occur between the power lines when internal and external faults occur in the bus system are accurately identified. A protection criterion is constructed using the Tanimoto coefficient (TC) because the TC construction mode and the corresponding characteristics can reliably identify the spectral waveform change trend, making the criterion largely unaffected by noise and fault resistance variations. PSCAD/EMTDC simulation results reveal that the proposed method is faster and more sensitive than the existing protection method, particularly for protecting against internal high-resistance faults and external faults with loud noise interference. laboratory testing verifies the effectiveness of the proposed method and it is suitable to realize the industry application with new energy access. © 2001-2012 IEEE.

关键词： Frequency domain analysis

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Physics-Based Predictions of the Month-by-Month Summer Western North Pacific Anomalous Anticyclone

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Journal of Climate 2025年第10期38卷 2187-2203页

作者： Zhu, Zhiwei Yang, Ying Liu, Boqi State Key Laboratory of Climate System Prediction and Risk Management Key Laboratory of Meteorological Disaster Ministry of Education Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and Technology Nanjing China State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences Beijing China

This study identified the distinct predictors of the western North Pacific anomalous anticyclone (WNPAC) in June, July, and August and revealed their independent influencing mechanisms on the formation of the summer WNPAC in each corresponding month. For the June WNPAC (AC_Jun), the North Atlantic warming (NAW) in April–May induces subsequently enhanced convection over the Indian Ocean and suppressed the convection over the tropical central Pacific, leading to AC_Jun via the Gill-type response. Meanwhile, the warming tendency over the western North Pacific from February to April, which reflects the slow decay of El Niño, results in AC_Jun through Indian Ocean warming. For the July WNPAC (AC_Jul), the cooling tendency from April to June over the central and eastern tropical Pacific is the sole predictor, which results in AC_Jul through the wind–evaporation–SST feedback. For the August WNPAC (AC_Aug), the tropical Atlantic warming (TAW) in June and July and the Bering Strait sea ice slow melting (BSSM) from April to May are the two predictors. While TAW has a similar influence on AC_Aug to that of NAW on AC_Jun, BSSM makes for AC_Aug by strengthening the westerly jet and subsequently atmosphere–ocean coupling over the North Pacific. Using these predictors, three physics-based empirical models (PEMs) for the seasonal predictions of AC_Jun, AC_Jul, and AC_Aug are conducted, which all outperform the National Centers for Environmental Prediction Climate Forecast System (CFS), shedding light on improving the seasonal prediction of the East Asian summer climate. © 2025 American Meteorological Society.

关键词： Heat flux

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Development and application of rock rheological constitutive model considering dynamic stress field and seepage field

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International Journal of Mining science and technology 2025年第3期35卷 467-482页

作者： Yian Chen Guangming Zhao Wensong Xu Shoujian Peng Jiang Xu Key Laboratory of Safe and Effective Coal Mining Ministry of Education Anhui University of Science and TechnologyHuainan 232001China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400044China

The generalized rheological tests on sandstone were conducted under both dynamic stress and seepage *** results demonstrate that the rheological strain of the specimen under increased stress conditions is greater than that under creep conditions,indicating that the dynamic stress field significantly influences the rheological behaviours of *** the rheological tests,the number of small pores in the sandstone decreased,while the number of medium-sized pores increased,forming new seepage *** high initial rheological stress accelerated fracture compression and the closure of seepage channels,resulting in reduction in the permeability of *** on the principles of generalized rheology and the experimental findings,a novel rock rheological constitutive model incorporating both the dynamic stress field and seepage properties has been *** simulations of surrounding rock deformation in geotechnical engineering were carried out using a secondary development version of this model,which confirmed the applicability of the generalized rheological numerical simulation *** results provide theoretical support for the long-term stability evaluation of engineering rock masses and for predicting the deformation of surrounding rock.

关键词： Generalized rheological test Seepage-stress coupling Seepage properties Dynamic stress field Rheological constitutive model

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High-precision magnetic field measurement system based on a coherent population trapping magnetometer onboard the SATech-01 satellite

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science China(Technological sciences) 2025年第2期68卷 227-242页

作者： Hongbo XUE Wei SONG Haoran ZHAO Yiteng ZHANG Shanzhi YE Jindong WANG Ran TAO Peng SANG Keli CHEN Xingzi BI Bingjun CHENG Bin ZHOU Yongliang XUE Yingying TANG Liu LIU Jinsong LI Xiaocheng ZHU Baoquan LI Jinguo LIU Wen CHEN Xiaofeng ZHANG Yonghe ZHANG Lei LI State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China Key Laboratory of Solar Activity and Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China Key Laboratory of Electronics and Information Technology for Space Systems National Space Science CenterChinese Academy of SciencesBeijing 100190China State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang 110016China Innovation Academy for Microsatellites Chinese Academy of SciencesShanghai 201304China

On July 27,2022,a high-precision system for measuring the magnetic field based on a coherent population trapping magnetometer(referred to as the CPT system)was launched onboard the Space Advanced technology demonstration satellite(SATech-01)by a ZK-1A *** payload comprises a scalar coherent population trapping magnetometer(CPTM),triaxial anisotropic magnetoresistance magnetometer(AMRM),and nano star tracker mounted on a non-magnetic telescopic tubular *** configuration enables synchronized measurement of scalar and vector geomagnetic fields,as well as the attitude,making the payload with its compact sensors suitable for applications on miniature satellite *** November 7,2022,the novel telescopic tubular mast was deployed in orbit,extending to a length of 5.28 *** CPTM,an absolute scalar magnetometer with an omnidirectional sensor,is the first China-developed quantum/atomic magnetometer successfully operating in *** orbit,the CPTM has sensitivity of~10 pT/Hz^(1/2) and can automatically operate under complex magnetic field *** difference between the scalar fields obtained using the CPTM and CHAOS model has a mean deviation of -3.73 nT and a standard deviation of 26.11 nT(1σ),without on-orbit calibration or *** miniaturized AMRM has a sensitivity of~0.3 nT/Hz^(1/2) and maintains stable and reliable operation in *** low-power and miniaturized nano star tracker has a measurement uncertainty of 14.23″(1σ)in *** mission has realized the on-orbit technical verification of the integrated and synchronized detection of the vector magnetic field and attitude and fully validated the system’s performance,automation level,and reliability.

关键词： magnetic field measurement system coherent population trapping magnetometer anisotropic magnetoresistance magnetometer nano star tracker non-magnetic telescopic tubular mast satellite

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Comprehensive Assessment of AIRS, TSHS, and VASS Temperature Profile Products in the Arctic Land Region

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Advances in Atmospheric sciences 2025年 1-14页

作者： Fan, Rongfeng Zhang, Lei Chen, Junming Wei, Ting Huang, Wentao Tian, Biao Ding, Minghu State Key Laboratory of Disaster Weather Science and Technology Chinese Academy of Meteorological Sciences Beijing China China Meteorological Administration Xiong’an Atmospheric Boundary Layer Key Laboratory Xiong’an New Area China MNR Key Laboratory for Polar Science Polar Research Institute of China Shanghai China Key Laboratory of Polar Atmosphere-ocean-ice System for Weather and Climate Ministry of Education Shanghai China

The Atmospheric Infrared Sounder (AIRS) on the Aqua satellite, along with the MWTS/MWHS Synergy (TSHS) sounding system and Atmospheric Vertical Sounder System (VASS) on the Fengyun-3D (FY-3D) satellite, provide high-quality data for studying Arctic temperature change. The generalized cold bias of AIRS is confirmed through horizontal comparisons with Arctic land radiosonde stations. VASS corrects the warm bias of TSHS by incorporating the Hyperspectral Infrared Atmospheric Sounder-I (HIRAS-I). Vertical comparisons demonstrate that AIRS, TSHS, and VASS offer excellent temperature detection from the top of the boundary layer to the lower stratosphere (800–100 hPa). However, the overestimation and errors of stratospheric temperatures by TSHS and VASS increase with altitude (pressures below 60 hPa). Specifically, the warm bias trends at 0.06 K hPa−¹, reaching 2.87 K and 2.92 K at 10 hPa. Similarly, RMSE values trend at 0.05 K hPa⁻¹, reaching 3.62 K and 3.69 K at 10 hPa. The low correlation (R ⩾ 0.65) of TSHS near 250 hPa in summer is significantly improved in VASS (R ⩾ 0.78) after adding HIRAS-I. The high vertical resolution due to infrared hyperspectral resolution facilitates the detection of complex temperature junctions. The retrieval error of AIRS in the boundary layer increases with cloudiness, while VASS combines microwave and infrared channel data to reduce the impact of cloud cover. Assessing the Arctic applicability of these three satellite temperature profile products will facilitate their widespread use in the Arctic region, enhance accurate climate change monitoring, and further reveal the mechanisms of Arctic warming. © Institute of Atmospheric Physics/Chinese Academy of sciences, and science Press 2025.

关键词： AIRS Arctic temperature TSHS VASS

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Effects of aggregate size distribution and carbon nanotubes on the mechanical properties of cemented gangue backfill samples under true triaxial compression

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 311-324页

作者： Qian Yin Fan Wen Zhigang Tao Hai Pu Tianci Deng Yaoyao Meng Qingbin Meng Hongwen Jing Bo Meng Jiangyu Wu State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and TechnologyHuainan 232001China State Key Laboratory for Geomechanics&Deep Underground Engineering China University of Mining and Technology(Beijing)Beijing 100083China Key Laboratory of Xinjiang Coal Resources Green Mining Ministry of EducationXinjiang Institute of EngineeringUrumqi 830023China

The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious ***,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of *** mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically *** results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,***,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the ***σ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite ***ε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse *** increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.

关键词： cemented gangue backfill materials particle size distribution true triaxial compression test carbon nanotubes mechanical properties failure modes

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Experimental and numerical simulation of the attenuation effect of blast shock waves in tunnels at different altitudes

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Defence technology(防务技术) 2025年第1期43卷 120-141页

作者： Changjiang Liu Hujun Li Zhen Wang Yong He Guokai Zhang Mingyang Wang School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China State Key Laboratory of Disaster Prevention and Mitigation of Explosion and Impact People's Liberation Army Engineering UniversityNanjing 210014China

Traffic engineering such as tunnels in various altitudinal gradient zone are at risk of accidental explosion,which can damage personnel and *** prediction of the distribution pattern of explosive loads and shock wave propagation process in semi-enclosed structures at various altitude environment is key research focus in the fields of explosion shock and fluid *** effect of altitude on the propagation of shock waves in tunnels was investigated by conducting explosion test and numerical *** on the experimental and numerical simulation results,a prediction model for the attenuation of the peak overpressure of tunnel shock waves at different altitudes was *** results showed that the peak overpressure decreased at the same measurement points in the tunnel entrance under the high altitude *** contrast,an increase in altitude accelerated the propagation speed of the shock wave in the *** average error between the peak shock wave overpressure obtained using the overpressure prediction formula and the measured test data was less than15%,the average error between the propagation velocity of shock waves predicted values and the test data is less than 10%.The method can effectively predict the overpressure attenuation of blast wave in tunnel at various altitudes.

关键词： Shock wave propagation Tunnel Altitude effect Peak overpressure Shock waves velocity Engineering safety

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Impacts of Land–Atmosphere Coupling on Summer Extreme Hot-Humid Compound Events over Southern Eurasia under Different Sea Surface Temperature Backgrounds

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Advances in Atmospheric sciences 2025年第4期42卷 744-760页

作者： Yajing QI Haishan CHEN Siguang ZHU State Key Laboratory of Climate System Prediction and Risk Management/Key Laboratory of Meteorological Disaster Ministry of Education/Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science and TechnologyNanjing 210044China School of Atmospheric Sciences Nanjing University of Information Science and TechnologyNanjing 210044China

Land–atmosphere coupling and sea surface temperature(SST)anomalies both have essential impacts on weather and climate *** on the ERA5 reanalysis dataset and the CESM1.2.2 model,this study investigates the influence of land–atmosphere coupling on summer extreme hot-humid events(EHHE)over southern Eurasia under different SST *** results suggest that coupling causes near-surface air temperature increases that exceed 0.5℃.From 1961 to 2020,the frequency of EHHE has continuously increased,and is closely related to soil moisture anomalies in the northern Indian Peninsula(IDP)and the middle and lower reaches of the Yangtze River(YRB).Numerical simulations further demonstrate that land–atmosphere coupling raises the risk of EHHE by 25.4%.In a typical El Niño SST background state,intensified land–atmosphere coupling tends to produce notable increases in the frequency of *** dominant processes that land–atmosphere coupling affects the EHHE variations are evidently different between these two *** surface thermal anomalies predominate in the IDP,while moisture conditions are more critical in the *** warm SST anomalies exist,dry soil anomalies in the IDP are prominent,and evaporation is constrained,increasing sensible heat *** geopotential height anomalies are significant,combined with adiabatic warming induced by descending motion and a noticeable warm center in the near-surface *** southward shift of the westerly jet enhances divergence over *** anticyclonic circulation anomalies over the western Pacific are conducive to guiding moisture transport to the YRB,providing a favorable circulation background for the development of summer EHHE.

关键词： land-atmosphere coupling sea surface temperature extreme hot-humid events southern Eurasia

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Estimating the Dst index using machine learning from IMAGE/HENA observations

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Advances in Space Research 2025年第6期75卷 4786-4794页

作者： Yan, Yuheng Yu, Xiancai Zhang, Xianguo Sun, Tianran Beijing Key Laboratory of Space Environment Exploration National Space Science Center Chinese Academy of Sciences Beijing China School of Computer Science and Technology University of Chinese Academy of Sciences Beijing China State Key Laboratory of Space Weather National Space Science Center CAS Beijing China

This study presents a novel approach to estimating the Disturbance Storm Time (Dst) index, a critical measure of geomagnetic storm activity, using Energetic Neutral Atom (ENA) observations from the High Energy Neutral Atom (HENA) imager on the IMAGE satellite. By applying machine learning techniques—specifically multilayer perceptrons (MLPs) and convolutional neural networks (CNNs) to ENA data from 2000 to 2005, we developed models that achieve a root mean square error (RMSE) of 18.96 nT and a correlation coefficient (R) of 0.87 in predicting the Dst index. This method offers a new, global perspective on geomagnetic storm dynamics by leveraging satellite-based ENA data, enhancing spatial and temporal resolution beyond ground-based magnetometer measurements. These findings show the potential of machine learning in improving space weather forecasting and deepening our understanding of geomagnetic storm dynamics. © 2024

关键词： Convolutional neural networks

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Enhanced influence of the North Atlantic Oscillation on winter snowfall in northern China since 2000

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science China Earth sciences 2025年第4期68卷 1236-1244页

作者： Botao ZHOU Chuer GUO Yuepeng HU Wenxin XIE Bo SUN Tingting HAN Ning SHI State Key Laboratory of Climate System Prediction and Risk Management/Key Laboratory of Meteorological Disaster Ministry of Education/Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science and TechnologyNanjing210044China School of Atmospheric Sciences Nanjing University of Information Science and TechnologyNanjing210044China Zhejiang Meteorological Observatory Hangzhou310002China

Because of the profound impacts of snowfall in northern China on the economy society and human lives,it is essential to understand the physical mechanisms behind the variability of snowfall in this *** on the observational and reanalysis data during 1961–2018,this study examines the relationship of winter snowfall over northern China with the North Atlantic Oscillation(NAO).The results show that their relationship experiences an interdecadal change around *** 2000–2018,the NAO is significantly and negatively correlated to winter snowfall in northern *** the NAO is in the negative phase,the East Asian subtropical jet and polar front jet tend to move northward and southward,respectively,concomitant with an anomalous cyclonic circulation from Lake Balkhash to Lake Baikal in the middle and lower *** an atmospheric background favors the increase of snowfall over northern China by empowering the interactions of cold air with moist airflows in the target ***,during 1981–1999,the association of the NAO with the above atmospheric circulations seems inconspicuous,thereby reducing its relation to winter snowfall in northern *** investigation suggests that the enhancement of the connection between the NAO and aforementioned atmospheric circulations may result from the westward displacement of the NAO southern center from the former period to the latter period.

关键词： Winter snowfall Northern China North Atlantic Oscillation Interdecadal change Atmospheric circulations

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