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A stable staggered-grid finite-difference scheme for acoustic modeling beyond conventional stability limit

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Petroleum Science 2024年第1期21卷 182-194页

作者： jing-Yi xu Yang Liu National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing 102249China China University of Petroleum(Beijing) Karamay CampusKaramay 834000XinjiangChina

Staggered-grid finite-difference(SGFD)schemes have been widely used in acoustic wave modeling for geophysical *** improved methods are proposed to enhance the accuracy of numerical ***,these methods are inevitably limited by the maximum Courant-Friedrichs-Lewy(CFL)numbers,making them unstable when modeling with large time sampling intervals or small grid *** solve this problem,we extend a stable SGFD scheme by controlling SGFD dispersion relations and maximizing the maximum CFL ***,to improve modeling stability,we minimize the error between the FD dispersion relation and the exact relation in the given wave-number region,and make the FD dispersion approach a given function outside the given wave-number area,thus breaking the conventional limits of the maximum CFL ***,to obtain high modeling accuracy,we use the SGFD scheme based on the Remez algorithm to compute the FD *** addition,the hybrid absorbing boundary condition is adopted to suppress boundary reflections and we find a suitable weighting coefficient for the proposed *** derivation and numerical modeling demonstrate that the proposed scheme can maintain high accuracy in the modeling process and the value of the maximum CFL number of the proposed scheme can exceed that of the conventional SGFD scheme when adopting a small maximum effective wavenumber,indicating that the proposed scheme improves stability during the modeling.

关键词： Acoustic wave Staggered-grid finite-difference(SGFD) modeling Courant-friedrichs-lewy(CFL)number Stability

Coordinated Voltage Control of Distribution Network ConsideringMultiple Types of Electric Vehicles

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Energy Engineering 2024年第2期121卷 377-404页

作者： liang Liu Guangda xu Yuan Zhao Yi Lu Yu Li jing Gao State Grid Jibei Electric Power Research Institute(North China Electric Power Research Institute Co. Ltd.)Beijing100045China

The couple between the power network and the transportation network(TN)is deepening gradually with the increasing penetration rate of electric vehicles(EV),which also poses a great challenge to the traditional voltage control *** this paper,we propose a coordinated voltage control strategy for the active distribution networks considering multiple types of *** the first stage,the action of on-load tap changer and capacitor banks,etc.,are determined by optimal power flow calculation,and the node electricity price is also determined based on dynamic time-of-use tariff *** the second stage,multiple operating scenarios of multiple types of EVs such as cabs,private cars and buses are considered,and the scheduling results of each EV are solved by building an optimization model based on constraints such as queuing theory,Floyd-Warshall algorithm and traffic flow *** the third stage,the output power of photovoltaic and energy storage systems is fine-tuned in the normal control *** charging power of EVs is also regulated in the emergency control mode to reduce the voltage deviation,and the amount of regulation is calculated based on the fair voltage control mode of ***,we test the modified IEEE 33-bus distribution system coupled with the 24-bus Beijing *** simulation results show that the proposed scheme can mitigate voltage violations well.

关键词： Electric vehicle transportation network voltage control queuing theory

Hepatomegaly and jaundice as the presenting symptoms of systemic light-chain amyloidosis: A case report

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World Journal of Gastrointestinal Oncology 2024年第2期16卷 550-556页

作者： xu Zhang Fei Tang Yan-Ying Gao De-Zhao Song jing liang Department of Gastroenterology and Hepatology The Third Central Hospital of TianjinTianjin 300170China Tianjin Key Laboratory of Extracorporeal Life Support for Critical Diseases Artificial Cell Engineering Technology Research CenterTianjin Institute of Hepatobiliary DiseaseTianjin 300170China Department of Interventional Radiology The Third Central Hospital of TianjinTianjin 300170China

BACKGROUND Light chain(AL)amyloidosis is a plasma cell dyscrasia characterized by the pathologic production and extracellular tissue deposition of fibrillar proteins derived from immunoglobulin AL fragments secreted by a clone of plasma cells,which leads to progressive dysfunction of the affected *** two most commonly affected organs are the heart and kidneys,and liver is rarely the dominant affected organ with only 3.9%of cases,making them prone to misdia-gnosis and missed *** SUMMARY A 65-year-old woman was admitted with a 3-mo history of progressive jaundice and marked ***,based on enhanced computed tomography scan and angiography,Budd-Chiari syndrome was considered and balloon dilatation of significant hepatic vein stenoses was ***,addi-tional diagnostic procedures,including liver biopsy and bone marrow-exami-nation,revealed immunoglobulin kapa AL amyloidosis with extensive liver involvement and hepatic vascular *** disease course was progre-ssive and fatal,and the patient eventually died 5 mo after initial presentation of *** AL amyloidosis with isolated liver involvement is very rare,and can be easily misdiagnosed as a vascular disease.

关键词： Jaundice Hepatomegaly Liver amyloidosis Kappa light chain Pseudo-Budd-Chiari syndrome Case report

Research on key technologies of UAV cluster cooperative system for Internet of Things applications

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Journal of Control and Decision 2024年第1期11卷 26-35页

作者： xu jing Xi’an International University Xi’anPeople’s Republic of China

The combat tasks faced by UAVs are becoming more and more *** single UAVs are limited by the constraints of platform load capacity,lightweight load,and insufficient lowpower equipment,so it is difficult to complete complex tasks *** at typical UAV collaborative confrontation application scenarios,this paper constructs a multi-agentoriented cluster collaborative intelligent system architecture and establishes a swarm-oriented intelligent UAV cluster collaborative control ***,this paper forms a simulation environment for UAV cluster collaborative confrontation and completes the design and implementation of the UAV cluster collaborative confrontation system based on swarm *** addition,this paper analyses the key technologies of the UAV cluster collaborative system with the support of the Internet of Things technology and verifies the performance of the system after constructing the corresponding *** experimental results show that the system constructed in this paper is effective.

关键词： Internet of Things UAV cluster collaborative control key technology

Total synthesis of a putative yuzurimine-type Daphniphyllum alkaloid C_(14)–epi-deoxycalyciphylline H

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Chinese Chemical Letters 2024年第4期35卷 336-339页

作者： jingping Hu jing xu Shenzhen Grubbs Institute and Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis and Shenzhen Key Laboratory of Small Molecule Drug Discovery and Synthesis Southern University of Science and TechnologyShenzhen 518055China

One of the largest subfamilies within the famous Daphniphyllum alkaloid family is made up of the yuzurimine-type(or macrodaphniphyllamine-type) alkaloids. Their complex aza-polycyclic caged structures, several contiguous stereogenic centers, and vicinal all-carbon quaternary centers make these alkaloids formidable challenge for synthetic chemists. Recently, synthesis of these alkaloids has received extensive attention from our community. Herein, we wish to report the total synthesis of C_(14)–epideoxycalyciphylline H, a putative member of yuzurimine-type alkaloid subfamily. Key transformations employed in our approach include an intramolecular Prins reaction and a Pd-catalyzed enyne cycloisomerization. In addition, synthesis of a daphnezomine L-type alkaloid, paxdaphnidine A, was also studied.

关键词： Total synthesis Daphniphyllum alkaloids Yuzurimine-type alkaloids Prins reaction Enyne cycloisomerization

HgaNets:Fusion of Visual Data and Skeletal Heatmap for Human Gesture Action Recognition

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Computers, Materials & Continua 2024年第4期79卷 1089-1103页

作者： Wuyan liang Xiaolong xu School of Internet of Things Nanjing University of Posts and TelecommunicationsNanjing210023China School of Computer Science Nanjing University of Posts and TelecommunicationsNanjing210023China

Recognition of human gesture actions is a challenging issue due to the complex patterns in both visual andskeletal features. Existing gesture action recognition (GAR) methods typically analyze visual and skeletal data,failing to meet the demands of various scenarios. Furthermore, multi-modal approaches lack the versatility toefficiently process both uniformand disparate input ***, in this paper, an attention-enhanced pseudo-3Dresidual model is proposed to address the GAR problem, called HgaNets. This model comprises two independentcomponents designed formodeling visual RGB (red, green and blue) images and 3Dskeletal heatmaps, *** specifically, each component consists of two main parts: 1) a multi-dimensional attention module forcapturing important spatial, temporal and feature information in human gestures;2) a spatiotemporal convolutionmodule that utilizes pseudo-3D residual convolution to characterize spatiotemporal features of gestures. Then,the output weights of the two components are fused to generate the recognition results. Finally, we conductedexperiments on four datasets to assess the efficiency of the proposed model. The results show that the accuracy onfour datasets reaches 85.40%, 91.91%, 94.70%, and 95.30%, respectively, as well as the inference time is 0.54 s andthe parameters is 2.74M. These findings highlight that the proposed model outperforms other existing approachesin terms of recognition accuracy.

关键词： Gesture action recognition multi-dimensional attention pseudo-3D skeletal heatmap

Exploring centimeter-sized crystals of bismuth-iodide perovskite toward highly sensitive X-ray detection

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Chinese Chemical Letters 2024年第6期35卷 185-188页

作者： Xin Dong jing liang Zhijin xu Huajie Wu Lei Wang Shihai You Junhua Luo Lina Li College of Chemistry Fuzhou UniversityFuzhou 350116China State Key Laboratory of Structure Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China University of Chinese Academy of Sciences Beijing 100049China

Lead-halide perovskites exhibit outstanding performance in X-ray detection due to their intrinsic features such as high charge carrier mobility,large atomic number,and long carrier lifetime,but the toxicity of lead is regarded as the major factor hindering their ***,we introduce organic molecule(R)-(-)-2-methylpiperazine(R-MPz)into the bismuth-based structure to synthesize lead-free(R)-(H_(2)MPz)BiI_(5)(R-MBI).The high-quality centimeter-sized single crystals have been obtained,which show a low dark current and superior environmental ***,the single-crystal device of R-MBI exhibits a highμτproduct up to 1.88×10^(-4)cm^(2)/V and a low trap density of 1.21×10^(10)cm^(-3).Further,the detector displays excellent detection sensitivity of 263.58μC Gy_(air)^(-1)cm^(-2)and a favorable low detection limit of 4.35μGyair/s,both of which meet the requirement for medical *** findings shed light on the exploration of innovative bismuth-based hybrid perovskites for high-performance X-ray detection.

关键词： Perovskite Lead-free Bismuth-based X-ray detection Sensitivity

Impaired Spatial Firing Representations of Neurons in the Medial Entorhinal Cortex of the Epileptic Rat Using Microelectrode Arrays

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Research 2024年第2期2023卷 541-552页

作者： Zhaojie xu Fan Mo Gucheng Yang Penghui Fan Botao Lu Wei liang Fanli Kong Luyi jing Wei xu Juntao Liu Mixia Wang Yirong Wu Xinxia Cai State Key Laboratory of Transducer Technology Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Epilepsy severely impairs the cognitive behavior of *** remains unclear whether epilepsy-induced cognitive impairment is associated with neuronal activities in the medial entorhinal cortex(MEC),a region known for its involvement in spatial *** explore this neural mechanism,we recorded the spikes and local field potentials from MEC neurons in lithium-pilocarpine-induced epileptic rats using self-designed microelectrode *** the open field test,we identified spatial cells exhibiting spatially selective firing properties and assessed their spatial representations in relation to the progression of ***,we analyzed theta oscillations and theta modulation in both excitatory and inhibitory ***,we used a novel object recognition test to evaluate changes in spatial cognitive ability of epileptic *** the epilepsy modeling,the spatial tuning of various types of spatial cells had suffered a rapid and pronounced damage during the latent period(1 to 5 d).Subsequently,the firing characteristics and theta oscillations were *** the chronic period(>10 d),the performance in the novel object experiment *** conclusion,our study demonstrates the detrimental effect on spatial representations and electrophysiological properties of MEC neurons in the epileptic latency,suggesting the potential use of these changes as a"functional biomarker"for predicting cognitive impairment caused by epilepsy.

关键词： epilepsy impaired involvement

The Forecast Skills and Predictability Sources of Marine Heatwaves in the NUIST-CFS1.0 Hindcasts

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Advances in Atmospheric Sciences 2024年第8期41卷 1589-1600页

作者： jing MA Haiming xu Changming DONG jing-Jia LUO Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/KLME/ILCEC/Institute of Climate and Application Research(ICAR) Nanjing University of Information Science and TechnologyNanjingJiangsu 210044China

Using monthly observations and ensemble hindcasts of the Nanjing University of Information Science and Technology Climate Forecast System(NUIST-CFS1.0) for the period 1983–2020, this study investigates the forecast skill of marine heatwaves(MHWs) over the globe and the predictability sources of the MHWs over the tropical oceans. The MHW forecasts are demonstrated to be skillful on seasonal-annual time scales, particularly in tropical oceans. The forecast skill of the MHWs over the tropical Pacific Ocean(TPO) remains high at lead times of 1–24 months, indicating a forecast better than random chance for up to two years. The forecast skill is subject to the spring predictability barrier of El Nino-Southern Oscillation(ENSO). The forecast skills for the MHWs over the tropical Indian Ocean(TIO), tropical Atlantic Ocean(TAO), and tropical Northwest Pacific(NWP) are lower than that in the TPO. A reliable forecast at lead times of up to two years is shown over the TIO, while a shorter reliable forecast window(less than 17 months) occurs for the TAO and ***, the forecast skills for the TIO, TAO, and NWP are seasonally dependent. Higher skills for the TIO and TAO appear in boreal spring, while a greater skill for the NWP emerges in late summer-early autumn. Further analyses suggest that ENSO serves as a critical source of predictability for MHWs over the TIO and TAO in spring and MHWs over the NWP in summer.

关键词： marine heatwaves NUIST-CFS1.0 hindcasts forecast skill predictability source ENSO