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Chinese Journal of Aeronautics 2024年第8期37卷 404-420页

作者： Yuqing qiu Yan LI Jinxi LANG Yuxian LIU Zhong WANG School of Automation Northwestern Polytechnical UniversityXi’an 710129China

As the elevator and rudder can be used actively for control,in addition to the rotors,Coaxial High-speed Helicopters(CHHs)have the problems of control redundancy and changing control authority in the transition *** paper presents a robust-augmentation transitioning flight control design for a CHH under the adverse conditions of parametric uncertainties and external ***,based on control characteristic analysis,an Adaptive Filtered Nonlinear Dynamic Inversion(AFNDI)controller is proposed for the angular rate to handle the effect of unknown unstructured uncertainties and external *** analysis proves that the presented angular rate controller can guarantee steady-state and transient ***,the attitude angle and velocity controllers are also ***,an Incremental-based Nonlinear Prioritizing Control Allocation(INPCA)method is designed to take into account control surface transition and changing control authority,which efficiently distributes the required moments between coaxial rotors and aero-surfaces,and avoids the control reversal problem of the yaw *** the proposed control architecture,the low-pass filter is introduced to alleviate the adverse influence of time delay and measurement ***,the effectiveness of the proposed controller is demonstrated through nonlinear numerical simulations,and is compared with existing *** results show that the proposed control law can improve both capabilities of disturbance rejection and fast response,and works satisfactorily for the CHH transitioning control characteristic.

关键词： Coaxial high-speed helicopter Transition mode Attitude control Control allocation Robust adaptive control

Research on the Stability Analysis Method of DC Microgrid Based on Bifurcation and Strobe Theory

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Energy Engineering 2024年第4期121卷 987-1005页

作者： Wei Chen Nan qiu Xusheng Yang School of Electrical Engineering and Information Engineering Lanzhou University of TechnologyLanzhou730050China

During the operation of a DC microgrid,the nonlinearity and low damping characteristics of the DC bus make it prone to oscillatory *** this paper,we first establish a discrete nonlinear system dynamic model of a DC microgrid,study the effects of the converter sag coefficient,input voltage,and load resistance on the microgrid stability,and reveal the oscillation mechanism of a DC microgrid caused by a single ***,a DC microgrid stability analysis method based on the combination of bifurcation and strobe is used to analyze how the aforementioned parameters influence the oscillation characteristics of the ***,the stability region of the system is obtained by the Jacobi matrix eigenvalue *** simulation verifies the feasibility and effectiveness of the proposed method.

关键词： DC microgrid bifurcation nonlinear dynamics stability analysis oscillation characteristics

计及风险扩散的智能变电站二次系统风险评估模型

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电测与仪表 2020年第24期57卷 66-75页

作者：戴志辉韩健硕邱小强耿宏贤华北电力大学河北省分布式储能与微网重点实验室河北保定071003

智能变电站中引进智能电子设备和虚端子连接,促使在二次系统风险评估时需对智能电子设备间交互关系和智能变电站二次系统风险扩散过程进行深入研究。基于此,结合二次系统信息流和继电保护逻辑,建立保护系统依赖网络模型;并根据部分装置... 详细信息

智能变电站中引进智能电子设备和虚端子连接,促使在二次系统风险评估时需对智能电子设备间交互关系和智能变电站二次系统风险扩散过程进行深入研究。基于此,结合二次系统信息流和继电保护逻辑,建立保护系统依赖网络模型;并根据部分装置发生故障风险后引发的风险扩散过程,建立二次系统风险扩散模型;最后通过仿真分析得到二次系统风险扩散的特征,并从保护系统规模、风险恢复参数和误操作角度对二次系统进行了风险评估,验证了文中所提模型与方法的有效性。

关键词：智能变电站继电保护系统风险评估风险扩散复杂网络信息流相依网络

Exceptional reversed yield strength asymmetry in a rare-earth free Mg alloy containing quasicrystal precipitates

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Journal of Magnesium and Alloys 2024年第2期12卷 687-699页

作者： Qiang Yang Shuhui Lv Zixiang Yan Zefeng Xie Xin qiu State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022PR China School of Materials Science and Engineering Changchun University of Science and Technology130022PR China

This work reports an exceptional reversed yield strength asymmetry at room temperature for a rare-earth free magnesium alloy containing a mass of fine dispersed quasicrystal(I-phase)*** exhibiting traditional basal texture,it owns an exceptional CYS/TYS as high as~*** back-scattered diffraction(EBSD)and transmission electron microscopy(TEM)examinations indicate pyramidal and prismatic dislocations plus tensile twinning being activated after immediate yielding in compression while basal and non-basal dislocations in tension.I-phase particles transferred the concentrated stress by self-twinning to provide the driving force for tensile twin initiating in neighboring grains,thereby significantly increasing the critical resolved shear stress of tensile twinning to possibly the level of pyramidal slip,finally leading to the dominance of pyramidal slip plus tensile twinning in texture *** results in a higher contribution on yield strength by~55 MPa in compression than in tension,which reasonably agrees with the experimental yield strength difference(~38 MPa).It can be concluded that I-phase particles influence deformation modes in tension and in compression,finally result in reversed yield strength asymmetry.

关键词： Magnesium alloy Reversed yield strength asymmetry Transmission electron microscopy(TEM) Twinning Dislocations

The Influence of Airflow Transport Pathways on Precipitation during the Rainy Season in the Liupan Mountains of Northwest China

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Advances in Atmospheric Sciences 2024年第11期41卷 2215-2229页

作者： Yujun qiu Chunsong LU Zhiliang SHU Peiyun DENG Key Laboratory of Aerosol-Cloud-Precipitation of China Meteorological Administration Nanjing University of Information Science&TechnologyNanjing 210044China Key Laboratory for Meteorological Disaster Monitoring and Early Warning and Risk Management of Characteristic Agriculture in Arid Regions China Meteorological AdministrationYinchuan 750002China Ningxia Key Laboratory of Meteorological Disaster Prevention and Reduction Yinchuan 750002China

This study investigates the influence of airflow transport pathways on seasonal rainfall in the mountainous region of the Liupan Mountains(LM) during the rainy seasons from 2020 to 2022, utilizing observational data from seven ground gradient stations located on the eastern slopes, western slopes, and mountaintops combined with backward trajectory cluster analysis. The results indicate 1) that the LM's rainy season, characterized by overcast and rainy days, is mainly influenced by cold and moist airflows(CMAs) from the westerly direction and warm and moist airflows(WMAs) from a slightly southern direction. The precipitation amounts under four airflow transport paths are ranked from largest to smallest as follows: WMAs, CMAs, warm dry airflows(WDAs), and cold dry airflows(CDAs). 2) WMAs contribute significantly more to the intensity of regional precipitation than the other three types of airflows. During localized precipitation events,warm airflows have higher precipitation intensities at night than cold airflows, while the opposite is true during the afternoon. 3) During regional precipitation events, water vapor content is the primary influencing factor. Precipitation characteristics under humid airflows are mainly affected by high water vapor content, whereas during dry airflow precipitation, dynamic and thermodynamic factors have a more pronounced impact. 4) During localized precipitation events, the influence of dynamic and thermodynamic factors is more complex than during regional precipitation, with the precipitation characteristics of the four airflows closely related to their water vapor content, air temperature and humidity attributes, and orographic lifting. 5) Compared to regional precipitation, the influence of topography is more prominent in localized precipitation processes.

关键词： regional precipitation localized precipitation airflow transport water vapor flux instability energy topographic influence

Multilevel Attention Unet Segmentation Algorithmfor Lung Cancer Based on CT Images

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Computers, Materials & Continua 2024年第2期78卷 1569-1589页

作者： Huan Wang Shi qiu Benyue Zhang Lixuan Xiao Xi’an Institute of Optics and Precision Mechanics Chinese Academy of SciencesXi’anChina School of Biomedical Engineering Fourth Military Medical UniversityXi’anChina University of Illinois at Urbana Champion ChampaignUSA

Lung cancer is a malady of the lungs that gravely jeopardizes human ***,early detection and treatment are paramount for the preservation of human *** computed tomography(CT)image sequences can explicitly delineate the pathological condition of the *** meet the imperative for accurate diagnosis by physicians,expeditious segmentation of the region harboring lung cancer is of utmost *** utilize computer-aided methods to emulate the diagnostic process in which physicians concentrate on lung cancer in a sequential manner,erect an interpretable model,and attain segmentation of lung *** specific advancements can be encapsulated as follows:1)Concentration on the lung parenchyma region:Based on 16-bit CT image capturing and the luminance characteristics of lung cancer,we proffer an intercept histogram algorithm.2)Focus on the specific locus of lung malignancy:Utilizing the spatial interrelation of lung cancer,we propose a memory-based Unet architecture and incorporate skip connections.3)Data Imbalance:In accordance with the prevalent situation of an overabundance of negative samples and a paucity of positive samples,we scrutinize the existing loss function and suggest a mixed loss *** results with pre-existing publicly available datasets and assembled datasets demonstrate that the segmentation efficacy,measured as Area Overlap Measure(AOM)is superior to 0.81,which markedly ameliorates in comparison with conventional algorithms,thereby facilitating physicians in diagnosis.

关键词： Lung cancer computed tomography computer-aided diagnosis Unet segmentation

应用蛋白质芯片筛选壮族单纯性室间隔缺损血清标志蛋白

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广西医科大学学报 2007年第6期24卷 832-835页

作者：李永红仇小强曾小云广西壮族自治区疾病预防控制中心南宁530021 桂林医学院广西医科大学公共卫生学院流行病与统计学教研室

目的:应用蛋白质芯片技术筛选壮族单纯性室间隔缺损(VSD)血清标志蛋白。方法:用表面增强激光解吸、电离飞行时间质谱技术和CM10芯片检测25例壮族单纯性VSD患儿与36例儿科常见病患儿血清,用Ciphergen公司的BiomarkWizard软件分析数据。结... 详细信息

目的:应用蛋白质芯片技术筛选壮族单纯性室间隔缺损(VSD)血清标志蛋白。方法:用表面增强激光解吸、电离飞行时间质谱技术和CM10芯片检测25例壮族单纯性VSD患儿与36例儿科常见病患儿血清,用Ciphergen公司的BiomarkWizard软件分析数据。结果:有12个蛋白具有统计学差异,其中质荷比(m/z)6640.784、8570.154、8698.278、2244.582、5321.868、6441.972和7973.3107个蛋白在VSD患儿血清高表达,质荷比(m/z)2213.579、4604.572、2142.465、9198.582和2169.2645个蛋白下调。结论:蛋白质芯片技术是发现与筛选室间隔缺损血清标志蛋白的快速、有效的蛋白质组学工具。

关键词：室间隔缺损标志蛋白蛋白质芯片技术蛋白质组学

An Imbalanced Data Classification Method Based on Hybrid Resampling and Fine Cost Sensitive Support Vector Machine

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Computers, Materials & Continua 2024年第6期79卷 3977-3999页

作者： Bo Zhu Xiaona Jing Lan qiu Runbo Li College of Mechanical and Electrical Engineering Kunming University of Science&TechnologyKunming650500China

When building a classification model,the scenario where the samples of one class are significantly more than those of the other class is called data *** imbalance causes the trained classification model to be in favor of the majority class(usually defined as the negative class),which may do harm to the accuracy of the minority class(usually defined as the positive class),and then lead to poor overall performance of the model.A method called MSHR-FCSSVM for solving imbalanced data classification is proposed in this article,which is based on a new hybrid resampling approach(MSHR)and a new fine cost-sensitive support vector machine(CS-SVM)classifier(FCSSVM).The MSHR measures the separability of each negative sample through its Silhouette value calculated by Mahalanobis distance between samples,based on which,the so-called pseudo-negative samples are screened out to generate new positive samples(over-sampling step)through linear interpolation and are deleted finally(under-sampling step).This approach replaces pseudo-negative samples with generated new positive samples one by one to clear up the inter-class overlap on the borderline,without changing the overall scale of the *** FCSSVM is an improved version of the traditional *** considers influences of both the imbalance of sample number and the class distribution on classification simultaneously,and through finely tuning the class cost weights by using the efficient optimization algorithm based on the physical phenomenon of rime-ice(RIME)algorithm with cross-validation accuracy as the fitness function to accurately adjust the classification *** verify the effectiveness of the proposed method,a series of experiments are carried out based on 20 imbalanced datasets including both mildly and extremely imbalanced *** experimental results show that the MSHR-FCSSVM method performs better than the methods for comparison in most cases,and both the MSHR and the FCSSVM played significan

关键词： Imbalanced data classification Silhouette value Mahalanobis distance RIME algorithm CS-SVM

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嵌入式存储器容错方案可靠性评估

微电子学 2015年第2期45卷 275-280页

作者：支天杨海钢蔡刚秋小强中国科学院电子学研究所北京100190 中国科学院大学北京100190

随着工艺节点的不断降低,存储器的软错误率呈指数趋势上升,容错技术已成为存储器设计中的重要环节。依据美国NASA Rosetta实验数据,对错误检纠错码(EDAC:Error Detection and Correction)和不同的在线刷新模式组成的多种容错方案进行可... 详细信息

随着工艺节点的不断降低,存储器的软错误率呈指数趋势上升,容错技术已成为存储器设计中的重要环节。依据美国NASA Rosetta实验数据,对错误检纠错码(EDAC:Error Detection and Correction)和不同的在线刷新模式组成的多种容错方案进行可靠性建模与量化评估,提出了不同工艺节点下嵌入式存储器容错技术选择的判据方法。在地面单粒子模拟实验中进行验证,结果表明,该方法预测的失效率评估结果与实验测试结果的平均偏差约为10.3%。

关键词：可靠性评估容错技术嵌入式存储器

Comprehensive tensile properties improved by deep cryogenic treatment prior to aging in friction-stir-welded 2198 Al–Li alloy

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Rare Metals 2024年第10期43卷 5403-5409页

作者： Jian-qiu Sun Yue Ma Chong Gao Hong-Yun Luo School of Materials Science and Engineering Beihang University Chinalco Research Institute of Science and Technology

In order to improve the comprehensive mechanical properties,deep cryogenic treatment （DCT）prior to aging was carried out on friction-stir-welded（FSW） 2198 Al-Li alloy;afterward,the microstructure and tensile properties were characterized by means of optical microscopy （OM）,transmission electron microscopy（TEM） and tensile *** results show that FSW 2198 alloy through DCT prior to aging （DAT） possesses superior tensile properties than conventional aging treatment （AT）The microstructural analysis reveals that DAT alloy exhibits a finer grain structure,since DCT might effectively alleviate the residual stress in FSW 2198 alloy and thus decrease the driving force for grain coarsening in subsequent aging ***,DCT generates dislocation multiplication,which provides more preferential nucleation sites for T1 （Al2CuLi） phase during subsequent aging treatment,resulting in high-density fine T1 phases and thin precipitate-free zone within DAT *** reasonable microstructure leads to DAT alloy possessing better strength-ductility combination compared to AT alloy.

关键词： Al–Li alloy Deep cryogenic treatment Friction stir welding Tensile properties