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Wind disturbance compensated path-following control for fixed-wing UAVs in arbitrarily strong winds

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Chinese Journal of Aeronautics 2024年第2期37卷 431-445页

作者： Hao LU Lan GAO Yunda YAN Mingzhe hou Chenliang WANG Hangzhou Innovation Institute Beihang UniversityHangzhou 310051China School of Information Science and Technology Hangzhou Normal UniversityHangzhou 311121China Department of Computer Science University College LondonLondon WC1E 6BTUnited Kingdom Center for Control Theory and Guidance Technology Harbin Institute of TechnologyHarbin 150001China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

Wind is the primary challenge for low-speed fixed-wing unmanned aerial vehicles to follow a predefined flight *** cope with various wind conditions,this paper proposes a wind disturbance compensated path following control strategy where the wind disturbance estimate is incorporated with the nominal guiding vector field to provide the desired airspeed direction for the *** the control input vector for the outer-loop kinematic subsystem needs to satisfy a magnitude constraint,a scaling mechanism is introduced to tune the proportions of the compensation and nominal ***,an optimization problem is formulated to pursue a maximum wind compensation in strong winds,which can be solved analytically to yield two scaling factors.A cascaded inner-loop tracking controller is also designed to fulfill the outer-loop wind disturbance compensated guiding vector ***-fidelity simulation results under sensor noises and realistic winds demonstrate that the proposed path following algorithm is less sensitive to sensor noises,achieves promising accuracy in normal winds,and mitigates the deviation from a desired path in wild winds.

关键词： Path following Guiding vector field Wind disturbance Disturbance rejection Fixed wings

Heat Transfer Characteristics of a Microchannel Heat Sink with Highly-Dense Micro-Jet Arrays

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Journal of Thermal Science 2024年第3期33卷 1148-1160页

作者： ZHANG Yu CHEN Xiaoyan MIAO Lin CHEN Liang hou Yu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an710049China Beijing Aerospace Technology Institute Beijing100083China

This paper proposed a new structure of highly-dense micro-jet arrays for hybrid jet-impingement/microchannel heat sinks(~120 jet per cm^(2) with jet width of 0.35 mm).Parametric study is performed to investigate the influence of structure and flow parameters on the convective heat transfer of water jet cooling in confined *** simulation results show that the optimal jet width,jet spacing and impingement distance are around 0.2 mm,0.2 mm and 0.3 mm,respectively,which can achieve a low thermal resistance as well as a relatively low pressure *** analysis of the heat transfer pathways shows that the micro-fin jet structures can extend the impinging heat transfer area and conduct a considerable proportion of heat,which can reach up to 38.9%with the Reynolds number ranging from 797.1 to *** heat transfer characteristics in the heat sink will shift from impingement dominated heat transfer to the channel-convection dominated heat transfer as the jet impingement distance increases.A correlation is proposed to predict the average Nusselt number on the stagnation area for the heat sink with different structure parameters,and the deviations of predictions from the numerical results are less than 10%.

关键词： hybrid heat sink impingement microchannel thermal management high heat flux

GRIK1 promotes glioblastoma malignancy and is a novel prognostic factor of poor prognosis

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Oncology Research 2024年第4期32卷 727-736页

作者： GUOQIANG hou XINHANG XU WEIXING HU Department of Neurosurgery First Affiliated Hospital of Nanjing Medical UniversityNanjingChina Department of Neurosurgery Renji HospitalShanghai Jiao Tong UniversityShanghaiChina

Primary tumors of the central nervous system(CNS)are classified into over 100 different histological *** most common type of glioma is derived from astrocytes,and the most invasive glioblastoma(WHO IV)accounts for over 57%of these ***(GBM)is the most common and fatal tumor of the CNS,with strong growth and invasion capabilities,which makes complete surgical resection almost *** various treatment methods such as surgery,radiotherapy,and chemotherapy,glioma is still an incurable disease,and the median survival time of patients with GBM is shorter than 15 ***,molecular mechanisms of GBM characteristic invasive growth need to be clarified to improve the poor *** ionotropic receptor kainate type subunit 1(GRIK1)is essential for brain function and is involved in many mental and neurological ***,GRIK1’s pathogenic roles and mechanisms in GBM are still ***-nuclear RNA sequencing of primary and recurrent GBM samples revealed that GRIK1 expression was noticeably higher in the recurrent ***,immunohistochemical staining of an array of GBM samples showed that high levels of GRIK1 correlated with poor prognosis of GBM,consistent with The Cancer Genome Atlas *** of GRIK1 retarded GBM cells growth,migration,and *** together,these findings show that GRIK1 is a unique and important component in the development of GBM and may be considered as a biomarker for the diagnosis and therapy in individuals with GBM.

关键词： Glioblastoma GRIK1 Invasion Proliferation Prognosis

Machine Learning Analysis of Impact of Western US Fires on Central US Hailstorms

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Advances in Atmospheric Sciences 2024年第7期41卷 1450-1462页

作者： Xinming LIN Jiwen FAN Yuwei ZHANG ZJason hou Pacific Northwest National Laboratory RichlandWA 99354USA Argonne National Laboratory LemontIL 60439USA

Fires,including wildfires,harm air quality and essential public services like transportation,communication,and *** fires can also influence atmospheric conditions,including temperature and aerosols,potentially affecting severe convective ***,we investigate the remote impacts of fires in the western United States(WUS)on the occurrence of large hail(size:≥2.54 cm)in the central US(CUS)over the 20-year period of 2001–20 using the machine learning(ML),Random Forest(RF),and Extreme Gradient Boosting(XGB)*** developed RF and XGB models demonstrate high accuracy(>90%)and F1 scores of up to 0.78 in predicting large hail occurrences when WUS fires and CUS hailstorms coincide,particularly in four states(Wyoming,South Dakota,Nebraska,and Kansas).The key contributing variables identified from both ML models include the meteorological variables in the fire region(temperature and moisture),the westerly wind over the plume transport path,and the fire features(i.e.,the maximum fire power and burned area).The results confirm a linkage between WUS fires and severe weather in the CUS,corroborating the findings of our previous modeling study conducted on case simulations with a detailed physics model.

关键词： wildfire severe convective storm hailstorm machine learning

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基于驱动频率的硅微陀螺零偏补偿方法研究

传感技术学报 2012年第5期25卷 624-627页

作者：满海鸥肖定邦吴学忠陈志华侯占强总装驻常德地区军代室湖南常德415007 国防科技大学机电工程与自动化学院长沙410073

针对硅微陀螺的零偏受环境温度影响比较敏感的问题,研究了一种新的温度补偿方案。通过研究驱动频率的温度特性,发现驱动频率与温度之间存在很好的线性关系,经过适当的标定,驱动频率可以作为内置温度传感器取代传统的温度传感器,解决了... 详细信息

针对硅微陀螺的零偏受环境温度影响比较敏感的问题,研究了一种新的温度补偿方案。通过研究驱动频率的温度特性,发现驱动频率与温度之间存在很好的线性关系,经过适当的标定,驱动频率可以作为内置温度传感器取代传统的温度传感器,解决了传统传感器温度不准确和测量滞后的问题。建立了驱动频率与零偏的模型,对硅微陀螺的零偏进行了温度补偿验证。验证试验表明,在-40℃～60℃全温区范围内,零偏温度灵敏度由0.053°/(s.℃)提高到0.00244°/(s.℃),有效地改善了全温区的零偏温度系数。

关键词：硅微陀螺零偏温度补偿驱动频率

The abundance,distribution,and enrichment mechanism of harmful trace elements in coals from Guizhou,Southwestern China

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Acta Geochimica 2024年第5期43卷 889-903页

作者： Hui hou Wei Cheng Ruidong Yang Yan Zhang College of Mining Guizhou UniversityGuiyangChina National and Local Joint Laboratory of Engineering for Effective Utilization of RegionalMineral Resources from Karst Areas GuiyangChina Guizhou Key Laboratory of Comprehensive Utilization of Non-Metallic Mineral Resources GuiyangChina College of Resource and Environment Engineering Guizhou UniversityGuiyangChina

Coal seams can enrich a variety of harmful trace elements under specific geological *** spatial distribution of harmful trace elements in coal is extremely uneven,and the distribution characteristics of each element content are *** harmful elements released in the process of coal mining and utilization will cause serious harm to the environment and the human *** is of great resource significance to study the geochemistry of coal that affects the enrichment and distribution characteristics of harmful trace *** on the domestic and foreign literature on coal geochemistry in Guizhou published by previous investigators,this study counted 1097 sample data from 23 major coal-producing counties in Guizhou Province,systematically summarized the relevant research results of harmful trace elements in the coal of Guizhou,and revealed the overall distribution and enrichment characteristics of harmful trace elements in the coal of *** results show that the average contents of Cd,Pb,Se,Cu,Mo,U,V,As,Hg,and Cr in coal of Guizhou are higher than those in Chinese coal and world coal.A variety of harmful trace elements in the coal of Guizhou have high background values,especially in Liupanshui,Xingyi and Qianbei *** enrichment of various harmful trace elements in the Late Permian coal in Guizhou is mainly related to the combined action of various geological and geochemical *** supply of terrigenous debris and sedimentary environment may be the basic background of the enrichment of harmful elements in western Guizhou,while low-temperature hydrothermal activity and volcanic ash deposition may be the main reasons for the enrichment of harmful elements in southwestern Guizhou.

关键词： Harmful trace elements Distribution characteristics Enrichment law Geological and geochemical features Guizhou

Seamless Indoor-Outdoor Switching Localization Algorithm based on CKF

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Journal of Communications and Information Networks 2024年第1期9卷 88-98页

作者： Gang Yang Guodong hou Ningning Feng Weida Meng School of Communication and Information Engineering Xi’an University of Posts and TelecommunicationsXi’an 710121China

To solve the problem of large positioning error and discontinuous positioning of special forces members when moving in cross-region indoors and outdoors, and to compensate for the linearization error and local convergence problem that may exist in the extended Kalman filter(EKF)in nonlinear systems, that is,the iterative results may be trapped in a local optimum situation, a seamless indoor-outdoor switching localization algorithm based on cubature Kalman filter (CKF) is proposed. CKF does not require the computation of Jacobian matrices, which can improve computational efficiency and filtering accuracy to a certain extent. In the system, an inertial measurement unit (IMU) is employed to correct the positioning errors of ultra-wideband (UWB)and BeiDou navigation satellite system(BDS).The positioning data from UWB and BeiDou in cross-region are weighted fused and then fused with the data from the IMU using CKF to obtain the final accurate positioning information. This study designs a scene-switching mechanism to achieve seamless switching between indoor and outdoor positioning scenes. By jointly analyzing the positioning accuracy of UWB and BeiDou,the positioning scene is determined, and appropriate counting thresholds are set to avoid frequent erroneous scene switches. Experimental results show that the proposed algorithm achieves a positioning accuracy of approximately 21.7 cm in cross-region,which can enable seamless integration of indoor and outdoor positioning,avoid positioning jumps, and enhance positioning accuracy.

关键词： cubature Kalman filtering ultra-wideband inertial measurement unit fusion positioning seamless switching

Post-transcriptional regulation of DEAD-box RNA helicases in hematopoietic malignancies

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Genes & Diseases 2024年第5期11卷 315-323页

作者： Jiankun Fan Zhigang Li Li Pei Yu hou Institute of Life Sciences Chongqing Medical UniversityChongqing 400016China Department of Hematology Southwest HospitalThird Military Medical University(Army Medical University)Chongqing 400038China

Hematopoiesis represents a meticulously regulated and dynamic biological *** aberrations affecting blood cells,induced by various factors,frequently give rise to hematological *** instances are often accompanied by a multitude of abnormal post-transcriptional regulatory events,including RNA alternative splicing,RNA localization,RNA degradation,and ***,post-transcriptional regulation plays a pivotal role in preserving hematopoietic *** DEAD-Box RNA helicase genes emerge as crucial post-transcriptional regulatory factors,intricately involved in sustaining normal hematopoiesis through diverse mechanisms such as RNA alternative splicing,RNA modification,and ribosome *** review consolidates the existing knowledge on the role of DEAD-box RNA helicases in regulating normal hematopoiesis and underscores the pathogenicity of mutant DEADBox RNA helicases in malignant *** is placed on elucidating both the positive and negative contributions of DEAD-box RNA helicases within the hematopoietic system.

关键词： DEAD-box RNA helicase Hemopoietic system Post-transcriptional regulation Ribosomes assembly RNA alternative splicing

Research on Improved MobileViT Image Tamper Localization Model

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Computers, Materials & Continua 2024年第8期80卷 3173-3192页

作者： Jingtao Sun Fengling Zhang Huanqi Liu Wenyan hou School of Computer Science and Technology Xi’an University of Posts and TelecommunicationsXi’an710121China Shaanxi Key Laboratory of Network Data Analysis and Intelligent Processing Xi’an University of Posts and TelecommunicationsXi’an710121China

As image manipulation technology advances rapidly,the malicious use of image tampering has alarmingly escalated,posing a significant threat to social *** the realm of image tampering localization,accurately localizing limited samples,multiple types,and various sizes of regions remains a multitude of *** issues impede the model’s universality and generalization capability and detrimentally affect its *** tackle these issues,we propose FL-MobileViT-an improved MobileViT model devised for image tampering *** proposed model utilizes a dual-stream architecture that independently processes the RGB and noise domain,and captures richer traces of tampering through dual-stream ***,the model incorporating the Focused Linear Attention mechanism within the lightweight network(MobileViT).This substitution significantly diminishes computational complexity and resolves homogeneity problems associated with traditional Transformer attention mechanisms,enhancing feature extraction diversity and improving the model’s localization *** comprehensively fuse the generated results from both feature extractors,we introduce the ASPP architecture for multi-scale feature *** facilitates a more precise localization of tampered regions of various ***,to bolster the model’s generalization ability,we adopt a contrastive learning method and devise a joint optimization training strategy that leverages fused features and captures the disparities in feature distribution in tampered *** strategy enables the learning of contrastive loss at various stages of the feature extractor and employs it as an additional constraint condition in conjunction with cross-entropy *** a result,overfitting issues are effectively alleviated,and the differentiation between tampered and untampered regions is *** evaluations on five benchmark datasets(IMD-20,CASIA,NIST-16,Columbia and Coverage)validat

关键词： Image tampering localization focused linear attention mechanism MobileViT contrastive loss