期刊文献+
共找到30,002篇文章
< 1 2 250 >
每页显示 20 50 100
基于多PRI脉压回波的单通道雷达干扰分离方法 被引量:1
1
作者 刘梅 杨威 +1 位作者 高勋章 刘永祥 《信息对抗技术》 2024年第1期70-80,共11页
研究了一种基于盲源分离的单通道雷达有源相干干扰抑制方法。针对伴随式干扰场景,在间歇采样转发干扰、部分脉冲密集转发干扰等有源相干干扰并存的条件下,建立了基于脉冲压缩的多脉冲重复间隔采样抗主瓣有源相干干扰模型并对其可行性进... 研究了一种基于盲源分离的单通道雷达有源相干干扰抑制方法。针对伴随式干扰场景,在间歇采样转发干扰、部分脉冲密集转发干扰等有源相干干扰并存的条件下,建立了基于脉冲压缩的多脉冲重复间隔采样抗主瓣有源相干干扰模型并对其可行性进行了证明。针对现有单通道盲源分离方法在时域进行分离效果有限的问题,提出对脉压后的距离维数据进行盲源分离的思想,可在一定程度上抑制噪声对盲源分离的影响。同时,由于目标信号和干扰信号在脉冲压缩后重合度较低,可获得更好的分离效果。仿真和实测结果表明,在多个干扰源存在的条件下,本方法可有效分离真实目标回波和干扰回波。当信噪比大于5 dB时,目标脉压回波相似系数接近100%;选取虚拟通道数越多,分离效果越好。 展开更多
关键词 单通道盲分离 pri采样 抗主瓣有源干扰 最小描述长度准则
下载PDF
基于时频域特征挖掘与自注意力机制融合的雷达PRI变化类型识别
2
作者 王军 薛磊 +2 位作者 屠俑霖 遇浩宁 姜建华 《信息对抗技术》 2024年第5期74-83,共10页
针对存在异常值时雷达辐射源脉冲重复间隔(pulse repetition interval,PRI)变化类型识别困难的问题,提出一种基于时频域特征挖掘与自注意力机制融合的雷达PRI变化类型识别方法。首先对PRI序列进行时序变化特征和小波特征分析,从时域和频... 针对存在异常值时雷达辐射源脉冲重复间隔(pulse repetition interval,PRI)变化类型识别困难的问题,提出一种基于时频域特征挖掘与自注意力机制融合的雷达PRI变化类型识别方法。首先对PRI序列进行时序变化特征和小波特征分析,从时域和频域2个角度构建特征集;然后基于自注意力机制以数据驱动的方式学习时频特征之间的互补性,有效把握不同维度特征对识别效果的贡献,实现对不同维度特征的深度融合;最后基于全连接神经网络对融合后的特征进行模式分类,从而实现对PRI变化类型的识别。仿真结果表明,在不同异常值水平下,所提方法能够显著提高对6种典型PRI变化类型的识别准确率,而且识别效果要显著优于仅使用单一维度特征的方法。 展开更多
关键词 时频域特征挖掘 小波变换 自注意力机制 神经网络 pri变化类型识别
下载PDF
基于脉冲序列重构的雷达PRI调制类型智能识别算法研究
3
作者 黄中瑞 唐波 《信号处理》 CSCD 北大核心 2024年第2期263-271,共9页
雷达脉冲重复间隔(PRI)是雷达信号的关键参数,对于雷达性能发挥起着至关重要的作用。研判雷达PRI调制类型能够为雷达识别和性能分析提供重要支撑,是电子对抗领域的关键研究内容。针对现有PRI调制类型识别准确率受脉冲丢失影响较大的问题... 雷达脉冲重复间隔(PRI)是雷达信号的关键参数,对于雷达性能发挥起着至关重要的作用。研判雷达PRI调制类型能够为雷达识别和性能分析提供重要支撑,是电子对抗领域的关键研究内容。针对现有PRI调制类型识别准确率受脉冲丢失影响较大的问题,本文提出了一种基于脉冲序列重构的雷达PRI调制类型智能识别算法。首先,基于到达时间(TOA)多阶差分序列实现了PRI调制周期的初步估计;其次,根据PRI调制周期重构了不同脉冲序列样本;再次,对重构样本进行去均匀值预处理,并以此为输入搭建了卷积神经网络(CNN)识别PRI调制类型,该方法能够减弱人工提取特征的局限性,不仅可以获取PRI序列的深层特征,而且具有更强的环境适用性;最后,仿真实验表明了所提方法的有效性。在脉冲丢失率小于60%时,所提方法对于所有PRI调制类型的识别准确率均在92%以上,平均识别准确率大于98%,在脉冲丢失率小于80%时,平均识别准确率在81%以上。 展开更多
关键词 脉冲丢失 pri调制周期 卷积神经网络 pri调制类型识别
下载PDF
Review of Fault-tolerant Control for Motor Inverter Failure with Operational Quality Considered
4
作者 Yuxuan Du Wenxiang Zhao +2 位作者 Yihua Hu Jinghua Ji Tao Tao 《CES Transactions on Electrical Machines and Systems》 EI CSCD 2024年第2期202-215,共14页
In recent years,motor drive systems have garnered increasing attention due to their high efficiency and superior control performance.This is especially apparent in aerospace,marine propulsion,and electric vehicles,whe... In recent years,motor drive systems have garnered increasing attention due to their high efficiency and superior control performance.This is especially apparent in aerospace,marine propulsion,and electric vehicles,where high performance,efficiency,and reliability are crucial.The ability of the drive system to maintain long-term fault-tolerant control(FTC)operation after a failure is essential.The likelihood of inverter failures surpasses that of other components in the drive system,highlighting its critical importance.Long-term FTC operation ensures the system retains its fundamental functions until safe repairs or replacements can be made.The focus of developing a FTC strategy has shifted from basic FTC operations to enhancing the post-fault quality to accommodate the realities of prolonged operation post-failure.This paper primarily investigates FTC strategies for inverter failures in various motor drive systems over the past decade.These strategies are categorized into three types based on post-fault operational quality:rescue,remedy,and reestablishment.The paper discusses each typical control strategy and its research focus,the strengths and weaknesses of various algorithms,and recent advancements in FTC.Finally,this review summarizes effective FTC techniques for inverter failures in motor drive systems and suggests directions for future research. 展开更多
关键词 FAULT-TOLERANT Motor drive Operation quality inverter failure
下载PDF
Review of Three-phase Soft Switching Inverters and Challenges for Motor Drives
5
作者 Haifeng Lu Qiao Wang +1 位作者 Jianyun Chai Yongdong Li 《CES Transactions on Electrical Machines and Systems》 EI CSCD 2024年第2期177-190,共14页
For electric vehicles (EVs),it is necessary to improve endurance mileage by improving the efficiency.There exists a trend towards increasing the system voltage and switching frequency,contributing to improve charging ... For electric vehicles (EVs),it is necessary to improve endurance mileage by improving the efficiency.There exists a trend towards increasing the system voltage and switching frequency,contributing to improve charging speed and power density.However,this trend poses significant challenges for high-voltage and high-frequency motor controllers,which are plagued by increased switching losses and pronounced switching oscillations as consequences of hard switching.The deployment of soft switching technology presents a viable solution to mitigate these issues.This paper reviews the applications of soft switching technologies for three-phase inverters and classifies them based on distinct characteristics.For each type of inverter,the advantages and disadvantages are evaluated.Then,the paper introduces the research progress and control methods of soft switching inverters (SSIs).Moreover,it presents a comparative analysis among the conventional hard switching inverters (HSIs),an active clamping resonant DC link inverter (ACRDCLI) and an auxiliary resonant commuted pole inverter (ARCPI).Finally,the problems and prospects of soft switching technology applied to motor controllers for EVs are put forward. 展开更多
关键词 Soft switching inverters Zero-voltage switching Electric vehicles Motor drives
下载PDF
Adaptive Predefined-Time Backstepping Control for Grid Connected Photovoltaic Inverter
6
作者 Jiarui Zhang Dan Liu +4 位作者 Kan Cao Ping Xiong Xiaotong Ji Yanze Xu Yunfei Mu 《Energy Engineering》 EI 2024年第8期2065-2083,共19页
The system performance of grid-connected photovoltaic(PV)has a serious impact on the grid stability.To improve the control performance and shorten the convergence time,a predefined-time controller based on backsteppin... The system performance of grid-connected photovoltaic(PV)has a serious impact on the grid stability.To improve the control performance and shorten the convergence time,a predefined-time controller based on backstepping technology and dynamic surface control is formulated for the inverter in the grid-connected photovoltaic.The time-varying tuning functions are introduced into state-tracking errors to realize the predefined-time control effect.To address the“computational explosion problem”in the design process of backstepping control,dynamic surface control is adopted to avoid the analytical calculations of virtual control.The disturbances of the PV system are estimated and compensated by adaptive laws.The control parameters are chosen and the global stability of the closed-loop is ensured by Lyapunov conditions.Simulation results confirm the effectiveness of the proposed controller and ensure the predefined time control in the photovoltaic inverter. 展开更多
关键词 Photovoltaic inverter system backstepping technology predefined-time control adaptive control
下载PDF
A novel cascaded H-bridge photovoltaic inverter with flexible arc suppression function
7
作者 Junyi Tang Wei Gao 《Global Energy Interconnection》 EI CSCD 2024年第4期513-527,共15页
This paper presents a novel approach that simultaneously enables photovoltaic(PV)inversion and flexible arc suppression during single-phase grounding faults.Inverters compensate for ground currents through an arc-elim... This paper presents a novel approach that simultaneously enables photovoltaic(PV)inversion and flexible arc suppression during single-phase grounding faults.Inverters compensate for ground currents through an arc-elimination function,while outputting a PV direct current(DC)power supply.This method effectively reduces the residual grounding current.To reduce the dependence of the arc-suppression performance on accurate compensation current-injection models,an adaptive fuzzy neural network imitating a sliding mode controller was designed.An online adaptive adjustment law for network parameters was developed,based on the Lyapunov stability theorem,to improve the robustness of the inverter to fault and connection locations.Furthermore,a new arc-suppression control exit strategy is proposed to allow a zerosequence voltage amplitude to quickly and smoothly track a target value by controlling the nonlinear decrease in current and reducing the regulation time.Simulation results showed that the proposed method can effectively achieve fast arc suppression and reduce the fault impact current in single-phase grounding faults.Compared to other methods,the proposed method can generate a lower residual grounding current and maintain good arc-suppression performance under different transition resistances and fault locations. 展开更多
关键词 Photovoltaic inverter Flexible arc suppression Adaptive control Fuzzy neural network Sliding mode control Exit strategy
下载PDF
An Algorithm for Short-Circuit Current Interval in Distribution Networks with Inverter Type Distributed Generation Based on Affine Arithmetic
8
作者 Yan Zhang Bowen Du +3 位作者 Benren Pan GuannanWang Guoqiang Xie Tong Jiang 《Energy Engineering》 EI 2024年第7期1903-1920,共18页
During faults in a distribution network,the output power of a distributed generation(DG)may be uncertain.Moreover,the output currents of distributed power sources are also affected by the output power,resulting in unc... During faults in a distribution network,the output power of a distributed generation(DG)may be uncertain.Moreover,the output currents of distributed power sources are also affected by the output power,resulting in uncertainties in the calculation of the short-circuit current at the time of a fault.Additionally,the impacts of such uncertainties around short-circuit currents will increase with the increase of distributed power sources.Thus,it is very important to develop a method for calculating the short-circuit current while considering the uncertainties in a distribution network.In this study,an affine arithmetic algorithm for calculating short-circuit current intervals in distribution networks with distributed power sources while considering power fluctuations is presented.The proposed algorithm includes two stages.In the first stage,normal operations are considered to establish a conservative interval affine optimization model of injection currents in distributed power sources.Constrained by the fluctuation range of distributed generation power at the moment of fault occurrence,the model can then be used to solve for the fluctuation range of injected current amplitudes in distributed power sources.The second stage is implemented after a malfunction occurs.In this stage,an affine optimization model is first established.This model is developed to characterizes the short-circuit current interval of a transmission line,and is constrained by the fluctuation range of the injected current amplitude of DG during normal operations.Finally,the range of the short-circuit current amplitudes of distribution network lines after a short-circuit fault occurs is predicted.The algorithm proposed in this article obtains an interval range containing accurate results through interval operation.Compared with traditional point value calculation methods,interval calculation methods can provide more reliable analysis and calculation results.The range of short-circuit current amplitude obtained by this algorithm is slightly larger than those obtained using the Monte Carlo algorithm and the Latin hypercube sampling algorithm.Therefore,the proposed algorithm has good suitability and does not require iterative calculations,resulting in a significant improvement in computational speed compared to the Monte Carlo algorithm and the Latin hypercube sampling algorithm.Furthermore,the proposed algorithm can provide more reliable analysis and calculation results,improving the safety and stability of power systems. 展开更多
关键词 Short circuit calculation inverter type distributed power supplies affine arithmetic distribution network
下载PDF
基于改进EVM的雷达PRI调制类型开集识别
9
作者 文秋月 王志勇 《现代雷达》 CSCD 北大核心 2024年第8期22-28,共7页
雷达脉冲重复间隔(PRI)的调制类型是分析雷达工作状态和任务的重要手段。针对常见PRI调制类型识别算法无法识别未知调制类型的问题,文中提出一种基于改进极值机(EVM)的雷达PRI调制类型开集识别方法。首先,采用残差-双向长短时记忆网络进... 雷达脉冲重复间隔(PRI)的调制类型是分析雷达工作状态和任务的重要手段。针对常见PRI调制类型识别算法无法识别未知调制类型的问题,文中提出一种基于改进极值机(EVM)的雷达PRI调制类型开集识别方法。首先,采用残差-双向长短时记忆网络进行PRI序列的特征提取;其次,结合原型学习,利用基于距离的交叉熵损失和原型损失对特征提取网络进行训练;最后,在特征空间中引入已知类特征的线性组合以模仿未知类的行为,提出了改进的EVM模型。实验结果表明,与EVM相比,文中所提方法能够提升雷达PRI调制类型的识别准确率,且在开放的电磁环境下具有良好的开集适应性。 展开更多
关键词 脉冲重复间隔调制类型 开集识别 残差网络 双向长短时记忆 原型学习 极值理论
原文传递
Estimating the Input Power of a Power Plant Using the Efficiency of the Inverter
10
作者 Toussaint Tilado Guingane Sosthène Tassembedo +3 位作者 Eric Korsaga Dominique Bonkoungou Zacharie Koalaga François Zougmore 《Smart Grid and Renewable Energy》 2024年第3期99-106,共8页
The study focuses on estimating the input power of a power plant from available data, using the theoretical inverter efficiency as the key parameter. The paper addresses the problem of missing data in power generation... The study focuses on estimating the input power of a power plant from available data, using the theoretical inverter efficiency as the key parameter. The paper addresses the problem of missing data in power generation systems and proposes an approach based on the efficiency formula widely documented in the literature. In the absence of input data, this method makes it possible to estimate the plant’s input power using data extracted from the site, in particular that provided by the Ministry of the Environment. The importance of this study lies in the need to accurately determine the input power in order to assess the overall performance of the energy system. 展开更多
关键词 Estimation Data MISSING INPUT POWER EFFICIENCY inverter
下载PDF
Coordinated Capacitor Voltage Balancing Method for Cascaded H-bridge Inverter with Supercapacitor and DC-DC Stage
11
作者 Ye Zhang Zixin Li +2 位作者 Fanqiang Gao Cong Zhao Yaohua Li 《CES Transactions on Electrical Machines and Systems》 EI CSCD 2024年第2期191-201,共11页
Cascaded H-bridge inverter(CHBI) with supercapacitors(SCs) and dc-dc stage shows significant promise for medium to high voltage energy storage applications. This paper investigates the voltage balance of capacitors wi... Cascaded H-bridge inverter(CHBI) with supercapacitors(SCs) and dc-dc stage shows significant promise for medium to high voltage energy storage applications. This paper investigates the voltage balance of capacitors within the CHBI, including both the dc-link capacitors and SCs. Balance control over the dc-link capacitor voltages is realized by the dcdc stage in each submodule(SM), while a hybrid modulation strategy(HMS) is implemented in the H-bridge to balance the SC voltages among the SMs. Meanwhile, the dc-link voltage fluctuations are analyzed under the HMS. A virtual voltage variable is introduced to coordinate the balancing of dc-link capacitor voltages and SC voltages. Compared to the balancing method that solely considers the SC voltages, the presented method reduces the dc-link voltage fluctuations without affecting the voltage balance of SCs. Finally, both simulation and experimental results verify the effectiveness of the presented method. 展开更多
关键词 Cascaded H-bridge inverter(CHBI) Hybrid modulation strategy(HMS) Capacitor voltage balancing DClink voltage fluctuation Supercapacitor(SC)
下载PDF
Model Predictive Control for Cascaded H-Bridge PV Inverter with Capacitor Voltage Balance
12
作者 Xinwei Wei Wanyu Tao +4 位作者 Xunbo Fu Xiufeng Hua Zhi Zhang Xiaodan Zhao Chen Qin 《Journal of Electronic Research and Application》 2024年第2期79-85,共7页
We designed an improved direct-current capacitor voltage balancing control model predictive control(MPC)for single-phase cascaded H-bridge multilevel photovoltaic(PV)inverters.Compared with conventional voltage balanc... We designed an improved direct-current capacitor voltage balancing control model predictive control(MPC)for single-phase cascaded H-bridge multilevel photovoltaic(PV)inverters.Compared with conventional voltage balanc-ing control methods,the method proposed could make the PV strings of each submodule operate at their maximum power point by independent capacitor voltage control.Besides,the predicted and reference value of the grid-connected current was obtained according to the maximum power output of the maximum power point tracking.A cost function was con-structed to achieve the high-precision grid-connected control of the CHB inverter.Finally,the effectiveness of the proposed control method was verified through a semi-physical simulation platform with three submodules. 展开更多
关键词 Model predictive control(MPC) Photovoltaic system Cascaded H-bridge(CHB)inverter Capacitor voltage balance
下载PDF
基于改进SAMP的频率捷变和PRI抖动雷达群目标检测 被引量:4
13
作者 杜慧茜 高浩东 +2 位作者 傅雄军 郎平 董健 《北京理工大学学报》 EI CAS CSCD 北大核心 2023年第1期87-93,共7页
针对群目标场景下目标个数未知和网格失配影响稀疏重构效果的问题,提出一种改进的稀疏度自适应匹配追踪(sparsity adaptive matching pursuit,SAMP)算法用于频率捷变和脉冲重复间隔(pulse repetition interval,PRI)抖动雷达的动目标检测... 针对群目标场景下目标个数未知和网格失配影响稀疏重构效果的问题,提出一种改进的稀疏度自适应匹配追踪(sparsity adaptive matching pursuit,SAMP)算法用于频率捷变和脉冲重复间隔(pulse repetition interval,PRI)抖动雷达的动目标检测.改进算法回溯阶段的原子选择策略,通过正则化挑选出能量相近的原子进行网格失配矫正,可以有效减小重构误差、抑制重构伪峰.根据重构信号的功率变化率自适应扩展支撑集长度(群目标个数估值),减少算法在同一步长的搜索时间.仿真结果表明,相比于SAMP算法和传统的群目标检测算法,本文改进的算法在提升重构效果的同时也能减小距离和速度测量误差. 展开更多
关键词 群目标检测 频率捷变 pri抖动 SAMP算法 网格失配
下载PDF
基于周期样本图重构的雷达PRI调制类型识别算法研究
14
作者 薛磊 黄中瑞 刘照龙 《信息对抗技术》 2023年第2期75-89,共15页
为提升对雷达脉冲重复间隔(pulse repetition interval,PRI)的分析性能,提出了一种基于周期样本图重构的雷达PRI调制类型识别算法。首先,建立了雷达PRI调制模型,分析了不同调制类型的信号特点;其次,利用到达时间(time of arrival,TOA)... 为提升对雷达脉冲重复间隔(pulse repetition interval,PRI)的分析性能,提出了一种基于周期样本图重构的雷达PRI调制类型识别算法。首先,建立了雷达PRI调制模型,分析了不同调制类型的信号特点;其次,利用到达时间(time of arrival,TOA)多阶差分序列估计了雷达PRI调制周期,并基于直方图算法重构了PRI周期样本图;然后,以PRI周期样本图为基础,提出了5个PRI调制特征实现PRI调制类型识别;该方法不仅能够提升PRI调制类型的识别准确率,而且对干扰脉冲特别是脉冲丢失具有很强的稳健性;最后,仿真实验表明了所提方法的有效性。 展开更多
关键词 脉冲丢失 脉冲重复间隔调制周期 pri周期样本图 pri调制类型识别
下载PDF
基于PRI变换快速雷达信号分选方法 被引量:2
15
作者 李斌 李杨 彭平 《电子信息对抗技术》 北大核心 2023年第2期42-50,共9页
脉冲重复间隔(Pulse Repetition Interval, PRI)变换法对典型雷达信号分选效果良好,但运算量大的缺点使其难以在复杂电磁环境下实现实时信号分选处理,因而制约其广泛应用。基于PRI变换法原理和运算复杂度模型,提出了PRI谱高次谐波抑制... 脉冲重复间隔(Pulse Repetition Interval, PRI)变换法对典型雷达信号分选效果良好,但运算量大的缺点使其难以在复杂电磁环境下实现实时信号分选处理,因而制约其广泛应用。基于PRI变换法原理和运算复杂度模型,提出了PRI谱高次谐波抑制和压缩PRI谱分辨率两种方法,对PRI变换法关键步骤进行优化,提升处理速度。仿真了6种典型重频类型雷达信号脉冲数据进行分选效果验证,结果表明所提方法能适应多种重频类型和复杂电磁环境信号分选,处理速度提升达几倍至几十倍,可明显提高PRI变换法的工程应用能力。 展开更多
关键词 雷达信号分选 pri变换 高次谐波抑制 压缩pri谱分辨率
下载PDF
一种基于PRI谱的自适应重频检测方法
16
作者 李斌 周彬 李杨 《电子信息对抗技术》 北大核心 2023年第3期24-31,共8页
脉冲重复间隔(Pulse Repetition Interval,PRI)变换方法能够适应典型重频(Pulse Repetition Frequency,PRF)类型雷达信号分选,但采用观察时间原则和谐波抑制原则生成检测门限分选过程中,容易出现多信号分选漏批情况。基于滑窗滤波技术原... 脉冲重复间隔(Pulse Repetition Interval,PRI)变换方法能够适应典型重频(Pulse Repetition Frequency,PRF)类型雷达信号分选,但采用观察时间原则和谐波抑制原则生成检测门限分选过程中,容易出现多信号分选漏批情况。基于滑窗滤波技术原理,提出PRI谱滑窗滤波重频检测方法,实现多信号自适应分选,提高PRI变换方法对复杂电磁环境的适应能力。仿真了6种典型重频类型雷达脉冲数据进行分选效果验证,结果表明所提方法具备典型类型重频雷达信号分选能力,多信号及复杂信号环境适应能力强,信号分选及脉冲提取准确率高。 展开更多
关键词 雷达信号分选 pri变换 重频检测 滑窗滤波
下载PDF
甲基转移酶3调控pri-miR-21甲基化修饰在糖尿病肾病肾脏纤维化中的作用 被引量:1
17
作者 吴佳晋 钟晨 +3 位作者 李大伟 陈若洋 瞿俊文 张明 《上海交通大学学报(医学版)》 CAS CSCD 北大核心 2023年第1期1-7,共7页
目的·探讨甲基转移酶3(methyltransferase like 3,METTL3)调控pri-miR-21的N^(6)-甲基腺苷(N^(6)-methyladenosine,m^(6)A)甲基化修饰在糖尿病肾病(diabetic nephropathy,DN)小鼠肾脏纤维化发病机制中的作用。方法·采用8周龄... 目的·探讨甲基转移酶3(methyltransferase like 3,METTL3)调控pri-miR-21的N^(6)-甲基腺苷(N^(6)-methyladenosine,m^(6)A)甲基化修饰在糖尿病肾病(diabetic nephropathy,DN)小鼠肾脏纤维化发病机制中的作用。方法·采用8周龄雄性db/db小鼠作为DN模型小鼠,db/m小鼠作为对照,同时按照是否经尾静脉注射S-腺苷高半胱氨酸水解酶抑制剂3-脱氮腺苷(3-deazaadenosine,DAA),共随机分为4组(5只/组),分别为db/m组、db/db组、db/m+DAA组和db/db+DAA组;8周龄开始注射DAA,注射1次/5 d,共注射8次。DAA干预结束后继续饲养小鼠至19周龄,收取各组小鼠血、尿、肾脏组织标本。检测血糖、血肌酐、尿白蛋白肌酐比(albumin-to-creatinine ratio,ACR),肾脏行苏木精-伊红(H-E)染色、Masson染色及天狼星红染色观察病理变化;试剂盒检测肾脏总RNA中m^(6)A的甲基化水平;Western blotting检测肾脏METTL3及纤维化相关蛋白表达;实时定量PCR检测肾脏总pri-miR-21和成熟miR-21;使用免疫磁珠富集肾脏组织中m^(6)A甲基化RNA,并通过PCR检测其中m^(6)A甲基化的pri-miR-21。结果·相较于db/m组,db/db组小鼠血糖,血肌酐,ACR,肾脏METTL3、m^(6)A甲基化修饰水平、纤维化相关蛋白、总pri-miR-21、m^(6)A甲基化pri-miR-21和成熟miR-21表达水平均显著增加(均P<0.05),小鼠肾脏系膜基质增多、肾小球基底膜增厚、胶原纤维累积显著增加。相较于db/db组,db/db+DAA组血糖,血肌酐,ACR,肾脏m^(6)A甲基化修饰水平、纤维化相关蛋白、m^(6)A甲基化pri-miR-21和成熟miR-21表达水平均显著下降(均P<0.05),总pri-miR-21表达水平显著升高(P=0.000),METTL3蛋白表达水平未见显著变化,小鼠肾脏损伤及纤维化程度显著减轻。结论·pri-miR-21的m^(6)A甲基化修饰促进miR-21成熟,进而促进DN小鼠肾脏纤维化的发生发展;抑制METTL3可通过调控pri-miR-21的m^(6)A甲基化修饰抑制DN小鼠肾脏纤维化。 展开更多
关键词 糖尿病肾病 肾脏纤维化 N^(6)-甲基腺苷 甲基转移酶3 pri-miR-21 MIR-21
下载PDF
基于YOLOv5与PRI变换的无人机编队检测 被引量:1
18
作者 杨波 孙闽红 +1 位作者 仇兆炀 韩文草 《现代雷达》 CSCD 北大核心 2023年第9期53-60,共8页
针对无人机编队数量的检测,文中从信号处理角度,提出了一种基于YOLOv5与脉冲重复间隔(PRI)变换的无人机编队检测算法。首先对无人机旋翼的雷达回波微多普勒信号进行建模与参数化表征,用时频变换方法得到微多普勒时频图,然后对其中的闪... 针对无人机编队数量的检测,文中从信号处理角度,提出了一种基于YOLOv5与脉冲重复间隔(PRI)变换的无人机编队检测算法。首先对无人机旋翼的雷达回波微多普勒信号进行建模与参数化表征,用时频变换方法得到微多普勒时频图,然后对其中的闪烁脉冲用YOLOv5进行检测并得到每个闪烁脉冲的位置信息,最后用PRI变换对闪烁脉冲进行分选,并基于分选结果得到无人机数量的估计。实验结果表明,该方法在信噪比为2 dB时,对4架无人机编队的检测准确率能够达到90%以上。 展开更多
关键词 无人机 编队数量检测 微多普勒 YOLOv5 脉冲重复间隔变换
原文传递
基于DBSCAN聚类和曲线拟合的PRI分选算法
19
作者 常安琪 乔宏乐 徐伟 《火控雷达技术》 2023年第2期21-26,共6页
随着电磁环境日益复杂多变,正确的雷达信号分选显得尤为重要。脉冲重复周期(Pulse Repetition Interval,PRI)作为雷达信号分类识别时的典型参数,可用于从交叠信号中分离出不同的雷达脉冲序列。针对高密度脉冲流条件下的PRI分选问题,本... 随着电磁环境日益复杂多变,正确的雷达信号分选显得尤为重要。脉冲重复周期(Pulse Repetition Interval,PRI)作为雷达信号分类识别时的典型参数,可用于从交叠信号中分离出不同的雷达脉冲序列。针对高密度脉冲流条件下的PRI分选问题,本文将带噪声的基于密度聚类(Density-Based Spatial Clustering of Application with Noise,DBSCAN)算法与曲线拟合算法相结合,通过Matlab仿真分析对比了其与经典序列差值直方图算法(Sequential Difference Histogram,SDIF)算法的分选正确率和抗噪性能,证明所提方法不仅能得出较高精度的脉冲序列测量值,且分选正确率更高。 展开更多
关键词 DBSCAN 曲线拟合 SDIF pri
下载PDF
Principle and parameter design of arc welding inverter using soft switching technique
20
作者 陈树君 冯雷 +2 位作者 李亮玉 殷树言 张树田 《China Welding》 EI CAS 1998年第1期63-70,共8页
The soft switching are welding inverter reduces switching losses and improves operating environment of devices by using Zero-Voltage-Transition (ZVT) technique. Step-by-step analysis of each timing interval and the as... The soft switching are welding inverter reduces switching losses and improves operating environment of devices by using Zero-Voltage-Transition (ZVT) technique. Step-by-step analysis of each timing interval and the associating voltage and current waveforms are included for the Full-Bridge Zero-Voltage-Switched PWM converter. Numerous design equations supporting the phase-shifted soft switching technique are highlighted. 展开更多
关键词 soft switching arc welding inverter Zero-Voltage-Transition (ZVT) Zero-Voltage-switching (ZVS)
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部