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Probing signals of atmospheric gravity waves excited by the July 29,2021 M_(W)8.2 Alaska earthquake

Geodesy and Geodynamics 2024年第3期15卷 219-229页

作者： Geng Zhang Jianqiao Xu xiaodong chen Heping Sun Lizhuo Gong State Key Laboratory of Geodesy and Earth's Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan430077China University of Chinese Academy of Sciences Beijing100049China

It is commonly believed that the atmosphere is decoupled from the solid Earth.Thus,it is difficult for the seismic wave energy inside the Earth to propagate into the atmosphere,and atmospheric pressure wave signals excited by earthquakes are unlikely to exist in atmospheric observations.An increasing number of studies have shown that earthquakes,volcanoes,and tsunamis can perturb the Earth's atmosphere due to various coupling effects.However,the observations mainly focus on acoustic waves with periods of less than 10 min and inertial gravity waves with periods of greater than 1 h.There are almost no clear observations of gravity waves that coincide with observations of low-frequency signals of the Earth's free oscillation frequency band within 1 h.This paper investigates atmospheric gravity wave signals within1 h of surface-atmosphere observations using the periodogram method based on seismometer and microbarometer observations from the global seismic network before and after the July 29,2021 M_(w)8.2 Alaska earthquake in the United States.The numerical results show that the atmospheric gravity wave signals with frequencies similar to those of the Earth's free oscillations _(0)S_(2) and _(0)T_(2) can be detected in the microbaro meter observations.The results con firm the existence of atmospheric gravity waves,indicating that the atmosphere and the solid Earth are not decoupled within this frequency band and that seismic wave energy excited by earthquakes can propagate from the interior of the Earth to the atmosphere and enhance the atmospheric gravity wave signals within 1 h.

关键词： Atmospheric gravity modes Atmospheric gravity waves Alaska earthquake Normal modes Coupling of solid earth and atmosphere

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Single photon emitter deterministically coupled to a topological corner state

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Light(Science & Applications) 2024年第1期13卷 135-141页

作者： Mujie Rao Fulong Shi Zhixuan Rao Jiawei Yang Changkun Song xiaodong chen Jianwen Dong Ying Yu Siyuan Yu State Key Laboratory of Optoelectronic Materials and Technologies School of Electronics and Information TechnologySchool of PhysicsSun Yat-Sen UniversityGuangzhou 510006China Hefei National Laboratory Hefei 230088China

Incorporating topological physics into the realm of quantum photonics holds the promise of developing quantum light emitters with inherent topological robustness and immunity to backscattering.Nonetheless,the deterministic interaction of quantum emitters with topologically nontrivial resonances remains largely unexplored.Here we present a single photon emitter that utilizes a single semiconductor quantum dot,deterministically coupled to a second-order topological corner state in a photonic crystal cavity.By investigating the Purcell enhancement of both single photon count and emission rate within this topological cavity,we achieve an experimental Purcell factor of Fp=3.7.Furthermore,we demonstrate the on-demand emission of polarized single photons,with a second-order autocorrelation function g(2)(0)as low as 0.024±0.103.Our approach facilitates the customization of light-matter interactions in topologically nontrivial environments,thereby offering promising applications in the field of quantum photonics.

关键词： topological quantum deterministic

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Enhancing the interfacial binding strength between modular stretchable electronic components

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National Science Review 2023年第1期10卷 49-67页

作者： Shaobo Ji xiaodong chen Innovative Centre for Flexible Devices(iFLEX) Max Planck-NTU Joint Lab for Artificial SensesSchool of Materials Science and Engineering Nanyang Technological University Institute of Materials Research and Engineering(IMRE) Agency for Science Technology and Research

Stretchable electronics are emerging for personalized and decentralized clinics,wearable devices and human-machine interactions.Nowadays,separated stretchable functional parts have been well developed and are approaching practical usage.However,the production of whole stretchable devices with full functions still faces a huge challenge:the integration of different components,which was hindered by the mechanical mismatch and stress/strain concentration at the connection interfaces.To avoid connection failure in stretchable devices,a new research focus is to improve the interfacial binding strength between different components.In this review,recent developments to enhance interfacial strength in wearable/implantable electronics are introduced and catalogued into three major strategies:(ⅰ) covalent bonding between different device parts,(ⅱ) molecular interpenetration or mechanical interlocking at the interfaces and(ⅲ) covalent connection between the human body and devices.Besides reviewing current methods,we also discuss the existing challenges and possible improvements for stretchable devices from the aspect of interfacial connections.

关键词： stretchable electronics interfacial strength covalent bonding mechanical interlocking device–human interfaces

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ThyroidNet:A Deep Learning Network for Localization and Classification of Thyroid Nodules

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Computer Modeling in Engineering & Sciences 2024年第4期139卷 361-382页

作者： Lu chen Huaqiang chen Zhikai Pan Sheng Xu Guangsheng Lai Shuwen chen Shuihua Wang xiaodong Gu Yudong Zhang Ultrasonic Department Zhongda Hospital Affiliated to Southeast UniversityNanjing210009China School of Physics and Information Engineering Jiangsu Second Normal UniversityNanjing211200China School of Computing and Mathematical Sciences University of LeicesterLeicesterLE17RHUK Department of Information Systems Faculty of Computing and Information TechnologyKing Abdulaziz UniversityJeddah21589Saudi Arabia State Key Laboratory of MillimeterWaves Southeast UniversityNanjing210096China Jiangsu Province Engineering Research Center of Basic Education Big Data Application Jiangsu Second Normal UniversityNanjing211200China School of Software Engineering Quanzhou Normal UniversityQuanzhou362000China Department of Biological Sciences Xi’an Jiaotong-Liverpool UniversitySuzhou215123China

Aim:This study aims to establish an artificial intelligence model,ThyroidNet,to diagnose thyroid nodules using deep learning techniques accurately.Methods:A novel method,ThyroidNet,is introduced and evaluated based on deep learning for the localization and classification of thyroid nodules.First,we propose the multitask TransUnet,which combines the TransUnet encoder and decoder with multitask learning.Second,we propose the DualLoss function,tailored to the thyroid nodule localization and classification tasks.It balances the learning of the localization and classification tasks to help improve the model’s generalization ability.Third,we introduce strategies for augmenting the data.Finally,we submit a novel deep learning model,ThyroidNet,to accurately detect thyroid nodules.Results:ThyroidNet was evaluated on private datasets and was comparable to other existing methods,including U-Net and TransUnet.Experimental results show that ThyroidNet outperformed these methods in localizing and classifying thyroid nodules.It achieved improved accuracy of 3.9%and 1.5%,respectively.Conclusion:ThyroidNet significantly improves the clinical diagnosis of thyroid nodules and supports medical image analysis tasks.Future research directions include optimization of the model structure,expansion of the dataset size,reduction of computational complexity and memory requirements,and exploration of additional applications of ThyroidNet in medical image analysis.

关键词： ThyroidNet deep learning TransUnet multitask learning medical image analysis

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Potential risks of organic contaminated soil after persulfate remediation:Harmful gaseous sulfur release

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Journal of Environmental Sciences 2024年第1期135卷 1-9页

作者： Yuyang Long Zixiao Wu xiaodong Ding Jiansong chen Dongsheng Shen Jiali Shentu Cai Hui Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling Zhejiang Engineering Research Center of Non-ferrous Metal Waste RecyclingInstrumental Analysis CenterSchool of Environmental Science and EngineeringZhejiang Gongshang UniversityHangzhou 310012China Shangyu Yingtai Fine Chemical Co. Ltd.Shaoxing 312000China Hangzhou Ecological Environment Monitoring Center Hangzhou 310007China

Persulfate is considered a convenient and efficient remediation agent for organic contaminated soil.However,the potential risk of sulfur into the soil remediation by persulfate remains ignored.In this study,glass bottles with different persulfate dosages and groundwater tables were set up to simulate persulfate remediation of organic pollutants(aniline).The results found sulfate to be the main end-product(83.0%–99.5%)of persulfate remediation after10 days.Moreover,H_(2)S accounted for 93.4%–99.4%of sulfur reduction end-products,suggesting that H_(2)S was the final fate of sulfur.H_(2)S was released rapidly after one to three days at a maximum concentration of 33.0 ppm,which is sufficient to make a person uncomfortable.According to the fitted curve results,H_(2)S concentration decreased to a safe concentration(0.15 ppm)after 20–85 days.Meanwhile,the maximum concentration of methanethiol reached 0.6 ppm.These results indicated that secondary pollution from persulfate remediation could release harmful gases over a long time.Therefore,persulfate should be used more carefully as a remediation agent for soil contamination.

关键词： Gaseous sulfur release H_2S Long period potential risk Organic contaminated soil remediation Persulfate

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Localization method of subsynchronous oscillation source based on high-resolution time-frequency distribution image and CNN

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Global Energy Interconnection 2024年第1期7卷 1-13页

作者： Hui Liu Yundan cheng Yanhui Xu Guanqun Sun Rusi chen xiaodong Yu Institute of Electric Power Systems School of Electrical and Electronic EngineeringNorth China Electric Power UniversityBeijing 102206P.R.China Electric Power Research Institute of State Grid Hubei Electric Power Co. Ltd.Wuhan 430077P.R.China Central China Branch of State Grid Corporation of China Wuhan 430077P.R.China

The penetration of new energy sources such as wind power is increasing,which consequently increases the occurrence rate of subsynchronous oscillation events.However,existing subsynchronous oscillation source-identification methods primarily analyze fixed-mode oscillations and rarely consider time-varying features,such as frequency drift,caused by the random volatility of wind farms when oscillations occur.This paper proposes a subsynchronous oscillation sourcelocalization method that involves an enhanced short-time Fourier transform and a convolutional neural network(CNN).First,an enhanced STFT is performed to secure high-resolution time-frequency distribution(TFD)images from the measured data of the generation unit ports.Next,these TFD images are amalgamated to form a subsynchronous oscillation feature map that serves as input to the CNN to train the localization model.Ultimately,the trained CNN model realizes the online localization of subsynchronous oscillation sources.The effectiveness and accuracy of the proposed method are validated via multimachine system models simulating forced and natural oscillation events using the Power Systems Computer Aided Design platform.Test results show that the proposed method can localize subsynchronous oscillation sources online while considering unpredictable fluctuations in wind farms,thus providing a foundation for oscillation suppression in practical engineering scenarios.

关键词： Subsynchronous oscillation source localization Synchronous squeezing transform Enhanced short-time Fourier transform Convolutional neural networks

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Efficient Spin-Flip between Charge-Transfer States for High-Performance Electroluminescence, without an Intermediate Locally Excited State

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Research 2024年第1期2023卷 339-349页

作者： Donghai Zhang Shanshan Jiang xiaodong Tao Fulin Lin Lingyi Meng Xu-Lin chen Can-Zhong Lu State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouFujian 350002China Fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China FuzhouFujian 350108China Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials Xiamen Institute of Rare Earth MaterialsHaixi InstitutesChinese Academy of SciencesXiamenFujian 361021China University of Chinese Academy of Sciences Beijing 100049China

Thermally activated delayed fluorescence(TADF)materials with both high photoluminescence quantum yield(PLQY)and fast reverse intersystem crossing(RISC)are strongly desired to realize efficient and stable organic light-emitting diodes(OLEDs).Control of excited-state dynamics via molecular design plays a central role in optimizing the PLQY and RISC rate of TADF materials but remains challenging.Here,3 TADF emitters possessing similar molecular structures,similar high PLQYs(89.5%to 96.3%),and approximate energy levels of the lowest excited singlet states(S_(1)),but significantly different spin-flipping RISC rates(0.03×10^(6) s^(−1) vs.2.26×10^(6) s^(−1))and exciton lifetime(297.1 to 332.8μs vs.6.0μs)were systematically synthesized to deeply investigate the feasibility of spin-flip between charge-transfer excited states(^(3)CT–^(1)CT)transition.

关键词： transition lifetime desired

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The impact of the Rural Minimum Living Standard Guarantee(Rural Dibao)Program on child nutrition outcomes

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Journal of Integrative Agriculture 2024年第2期23卷 444-456页

作者： Dian chen Xiangming Fang Yu chen xiaodong Zheng Zhuo chen Rodney B.W.Smith Academy of Global Food Economics and Policy China Agricultural UniversityBeijing 100083China School of Public Health Georgia State UniversityAtlanta 30303USA School of Economics Zhejiang Gongshang UniversityHangzhou 310018China College of Public Health University of GeorgiaAthens 30602USA Department of Applied Economics University of MinnesotaSaint Paul 55108USA

The Rural Minimum Living Standard Guarantee(Rural Dibao)is an important unconditional cash transfer program to alleviate poverty in rural China.Despite the importance of children’s nutrition in breaking poverty cycles,little is known about the impact of Rural Dibao on child nutrition outcomes.Using China Family Panel Studies(CFPS),this paper examines the effects of Rural Dibao on child nutrition outcomes and investigates potential pathways and heterogeneous effects.We exploit propensity score matching and difference-in-differences techniques to evaluate the effects of the Rural Dibao program on child nutrition outcomes.Our results suggest that Rural Dibao significantly impacts the nutrition outcomes of children up to 15 years of age.Specifically,our results suggest that Rural Dibao improves child height-to-age z-scores by 1.05 standard deviations and lowers the probability of stunting by 11.9 percentage points.Additional analyses suggest that increased protein intake is the main pathway through which Rural Dibao participation contributes to better nutrition outcomes.We also find that the effect of the program is more pronounced among girls,children who are non-left-behind or live with highly educated mothers,and those from low-income families and poor areas.Our findings suggest that Rural Dibao participation helps improve child nutrition outcomes through improving diet quality.

关键词： Rural Minimum Living Standard Guarantee nutrition height-to-age z-scores stunting rural China

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An Incentive Mechanism for Federated Learning:A Continuous Zero-Determinant Strategy Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 88-102页

作者： Changbing Tang Baosen Yang xiaodong Xie Guanrong chen Mohammed A.A.Al-qaness Yang Liu IEEE the College of Physics and Electronic Information Engineering Zhejiang Normal UniversityUniversityJinhua 321004China the School of Mathematical Sciences Zhejiang Normal UniversityJinhua 321004China the Department of Electrical Engineering City University of Hong KongHong KongChina Key Laboratory of Intelligent Education Technology and Application of Zhejiang Province Jinhua 321004China

As a representative emerging machine learning technique, federated learning(FL) has gained considerable popularity for its special feature of “making data available but not visible”. However, potential problems remain, including privacy breaches, imbalances in payment, and inequitable distribution.These shortcomings let devices reluctantly contribute relevant data to, or even refuse to participate in FL. Therefore, in the application of FL, an important but also challenging issue is to motivate as many participants as possible to provide high-quality data to FL. In this paper, we propose an incentive mechanism for FL based on the continuous zero-determinant(CZD) strategies from the perspective of game theory. We first model the interaction between the server and the devices during the FL process as a continuous iterative game. We then apply the CZD strategies for two players and then multiple players to optimize the social welfare of FL, for which we prove that the server can keep social welfare at a high and stable level. Subsequently, we design an incentive mechanism based on the CZD strategies to attract devices to contribute all of their high-accuracy data to FL.Finally, we perform simulations to demonstrate that our proposed CZD-based incentive mechanism can indeed generate high and stable social welfare in FL.

关键词： Federated learning(FL) game theory incentive mechanism machine learning zero-determinant strategy

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Organo-mineral complexes in soil colloids:Implications for carbon storage in saline-alkaline paddy soils from an eight-year field experiment

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Pedosphere 2024年第1期34卷 97-109页

作者： Mengmeng chen Shirong ZHANG Lu LIU Baojian CHANG Yuyi LI xiaodong DING College of Resources and Environment Qingdao Agricultural UniversityQingdao 266109China Jingke High-tech Institute of Environmental Sciences Co. LtdBeijing 100094China Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural SciencesBeijing 100081China

The combination of organic carbon(OC) and reactive minerals is a crucial mechanism of soil carbon(C) storage, which is regulated by the formation of organo-mineral complexes on the surface of soil colloids. The effect of organic fertilizer on the storage mechanism of OC in soil colloids was studied through an 8-year field experiment, which included four treatments: i) no fertilization(control, CK), ii) only mineral N, P, and K fertilization(NPK), iii) NPK plus a low level(450 kg C ha^(-1)year^(-1)) of organic fertilization(NPKC1), and iv) NPK plus a high level(900 kg C ha^(-1)year^(-1)) of organic fertilization(NPKC2). The main results indicated that organic fertilizer addition significantly increased the content of aromatic-C, which was 158.7% and 140.0% higher in soil colloids than in bulk soil in the NPKC1 and NPKC2 treatments, respectively. X-ray photoelectron spectroscopy further demonstrated that the relative proportion of C=C group on the surface of soil colloids was increased by 20.1% and 19.1% in the NPKC1 and NPKC2 treatments, respectively,compared with the CK. In addition, compared with the NPK treatment, the content of reactive minerals(such as Fe and Al oxides) significantly increased with organic fertilization, which was positively correlated with C=C group in soil colloids. This indicates that aromatic-C may be retained by the formation of aromatic-mineral complexes with reactive minerals in soil colloids. Organic fertilization also significantly increased OC storage efficiency(OCSE), which was significantly higher in the NPKC1 treatment than in the NPKC2 treatment. Therefore, a moderate amount of organic fertilizer application is a better agronomic practice to increase OCSE and OC storage in saline-alkaline paddy soils.

关键词： aromatic-C aromatic-mineral complex organic fertilization reactive mineral soil organic carbon water-dispersible colloid

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