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A New Design Approach for Nearly Linear Phase Stable IIR Filter using Fractional Derivative 被引量:1
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作者 Nikhil Agrawal Anil Kumar Varun Bajaj 《IEEE/CAA Journal of Automatica Sinica》 EI CSCD 2020年第2期527-538,共12页
In this paper,a new design method for digital infinite impulse response(IIR)filters with nearly linear-phase response is presented using fractional derivative constraints(FDCs).In the proposed method,design problem of... In this paper,a new design method for digital infinite impulse response(IIR)filters with nearly linear-phase response is presented using fractional derivative constraints(FDCs).In the proposed method,design problem of an IIR frlter is constructed as the minimization of phase error between the desired and designed phase response of an allpass filter(APF)such that the designed lowpass filter(LPF)or highpass frlter(HPF)yields less passband(ep),and stopband errors(es)with optimal stopband attenuation(As).In order to have accurate passband(pb)response,FDCs are imposed on appropriate reference frequency,where the optimality of these FDCs are ensured by using a new greedy based sorting mechanism.The simulated results reflect the efficiency of the proposed method in term of improved passband response along with better transition width.However,small reduction in^is observed within the allowable limit,when compared to noin-fractional design approach,but the designed filter remains immune to wordlength(WL)effect. 展开更多
关键词 Fractional derivative constraint(FDC) infinite impulse response(IIR)filter least squared linear phase QUANTIZATION
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A simple algorithm to calculate the pulsed sound field of a wide-band linear phased array
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作者 黄晶 阙沛文 +2 位作者 张志钢 雷华明 金建华 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2006年第4期427-430,共4页
A simple algorithm using an impulse response for a rectangular piston element is discussed. The impulse response of linear phased array is obtained hv stumming the impulse responses of rectangular piston elements with... A simple algorithm using an impulse response for a rectangular piston element is discussed. The impulse response of linear phased array is obtained hv stumming the impulse responses of rectangular piston elements with different delay times. The output response of the linear wide-band array is equal to the convolution of impulse response functions with wide-band pulse exeiting signal. Sound field distributions and impulse responses of three kinds of transducers are compared. The results can be used to optimize the parameters of the linear phased array transducers used in uhrasonie imaging in nondestructive testing (NDT). 展开更多
关键词 linear phased array ultrasonic transducer impulse response sound field
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Ultrasonic beam focusing characteristics of shear-vertical waves for contact-type linear phased array in solid 被引量:2
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作者 Yu-Xiang Dai Shou-Guo Yan Bi-Xing Zhang 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第3期270-276,共7页
We investigate the beam focusing technology of shear-vertical(SV) waves for a contact-type linear phased array to overcome the shortcomings of conventional wedge transducer arrays. The numerical simulation reveals the... We investigate the beam focusing technology of shear-vertical(SV) waves for a contact-type linear phased array to overcome the shortcomings of conventional wedge transducer arrays. The numerical simulation reveals the transient excitation and propagation characteristics of SV waves. It is found that the element size plays an important role in determining the transient radiation directivity of SV waves. The transient beam focusing characteristics of SV waves for various array parameters are deeply studied. It is particularly interesting to see that smaller element width will provide the focused beam of SV waves with higher quality, while larger element width may result in erratic fluctuation of focusing energy around the focal point. There exists a specific range of inter-element spacing for optimum focusing performance. Moreover, good beam focusing performance of SV waves can be achieved only at high steering angles. 展开更多
关键词 beam focusing shear-vertical(SV)waves contact-type linear phased array SOLID
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General FIR Filter Design with Linear Phase in Passband by Water Cycle Algorithm
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作者 Haijiang Hu Shaojing Song Yumei Gong 《Journal of Computer and Communications》 2018年第11期326-331,共6页
FIR filter is an important type of filter in the field of signal processing because of its inherent stability, simpler structure, and easier implementation on linear phase. WCA is used to solve FIR filter design with ... FIR filter is an important type of filter in the field of signal processing because of its inherent stability, simpler structure, and easier implementation on linear phase. WCA is used to solve FIR filter design with low magnitude error and linear phase in passband. This method uses WCA to optimize the filter coefficient based on the low magnitude errors in all frequency domains. Moreover, in the constraint conditions, the least group delay in passband is used for the optimization. The experiments testify this method has good performance on the passband error and group delay error in the passband. Therefore this method is an efficient algorithm for FIR filter optimization which can be used in the digital signal processing widely. 展开更多
关键词 FIR WCA linear phase Optimization
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Non-Linear Phase Tomography Based on Fréchet Derivative
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作者 Valentina Davidoiu Bruno Sixou +1 位作者 Max Langer Franoise Peyrin 《Advances in Computed Tomography》 2014年第4期39-50,共12页
Phase imaging coupled to micro-tomography acquisition has emerged as a powerful tool to investigate specimens in a non-destructive manner. While the intensity data can be acquired and recorded, the phase information o... Phase imaging coupled to micro-tomography acquisition has emerged as a powerful tool to investigate specimens in a non-destructive manner. While the intensity data can be acquired and recorded, the phase information of the signal has to be “retrieved” from the data modulus only. Phase retrieval is an ill-posed non-linear problem and regularization techniques including a priori knowledge are necessary to obtain stable solutions. Several linear phase recovery methods have been proposed and it is expected that some limitations resulting from the linearization of the direct problem will be overcome by taking into account the non-linearity of the phase problem. To achieve this goal, we propose and evaluate a non-linear algorithm for in-line phase micro-tomography based on an iterative Landweber method with an analytic calculation of the Fréchet derivative of the phase-intensity relationship and of its adjoint. The algorithm was applied in the projection space using as initialization the linear mixed solution. The efficacy of the regularization scheme was evaluated on simulated objects with a slowly and a strongly varying phase. Experimental data were also acquired at ESRF using a propagation-based X-ray imaging technique for the given pixel size 0.68 μm. Two regularization scheme were considered: first the initialization was obtained without any prior on the ratio of the real and imaginary parts of the complex refractive index and secondly a constant a priori value was assumed on ?. The tomographic central slices of the refractive index decrement were compared and numerical evaluation was performed. The non-linear method globally decreases the reconstruction errors compared to the linear algorithm and is achieving better reconstruction results if no prior is introduced in the initialization solution. For in-line phase micro-tomography, this non-linear approach is a new and interesting method in biomedical studies where the exact value of the a priori ratio is not known. 展开更多
关键词 phase Retrieval In-Line phase TOMOGRAPHY Inverse Problems NON-linear Problem NON-linear Optimization Fréchet DERIVATIVE Coherent IMAGING FRESNEL Diffraction phase Contrast X-Ray IMAGING
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Multi-Level Inverter Linear Predictive Phase Composition Strategy for UPQC
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作者 M.Hari Prabhu K.Sundararaju 《Intelligent Automation & Soft Computing》 SCIE 2023年第6期2947-2958,共12页
The power system is facing numerous issues when the distributed gen-eration is added to the existing system.The existing power system has not been planned with flawless power quality control.These restrictions in the ... The power system is facing numerous issues when the distributed gen-eration is added to the existing system.The existing power system has not been planned with flawless power quality control.These restrictions in the power trans-mission generation system are compensated by the use of devices such as the Static Synchronous Compensator(STATCOM),the Unified Power Quality Con-ditioner(UPQC)series/shunt compensators,etc.In this work,UPQC’s plan with the joint activity of photovoltaic(PV)exhibits is proposed.The proposed system is made out of series and shunt regulators and PV.A boost converter connects the DC link to the PV source,allowing it to compensate for voltage sags,swells,vol-tage interferences,harmonics,and reactive power issues.In this paper,the fea-tures of a seven-level Cascaded H-Bridge Multi-Level idea are applied to shunt and series active filter changeovers to reduce Total Harmonic Distortion and com-pensate for voltage issues.Despite its power quality capacity for common cou-pling,the proposed system can inject the grid’s dynamic power.During voltage interference,it can also provide a piece of delicate burden power.The simulation is carried out with the help of MATLAB/SIMULINK programming,and the results are compared to those of other conventional methods. 展开更多
关键词 Unified power quality conditioner PHOTOVOLTAIC linear predictive phase composition total harmonic distortion
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Construction of Two-Dimensional Compactly Supported Orthogonal Wavelets Filters with Linear Phase 被引量:8
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作者 Si Long PENG Institute of Automation, Academia Sinica, Beijing 100080. P. R. China 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2002年第4期719-726,共8页
In this paper, at large class of two-dimensional orthogonal wavelet filters, (lowpass and highpass), are presented in explicit expression. We also characterize the filters with linear phase in this case. Some examples... In this paper, at large class of two-dimensional orthogonal wavelet filters, (lowpass and highpass), are presented in explicit expression. We also characterize the filters with linear phase in this case. Some examples are also given, including non-separable filters with linear phase. 展开更多
关键词 TWO-DIMENSIONAL ORTHOGONAL linear phase WAVELET FILTERS
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Design of Perfect Reconstruction Cosine Modulated Filter Bank with Linear Phase
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作者 Tan, Ying 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1998年第1期24-30,共7页
We propose the quadratic constrained formulas for the design of linear phase cosine modulated paraunitary filter banks given in references . Using these formulae, we can, directly, optimize the prototype filter coeff... We propose the quadratic constrained formulas for the design of linear phase cosine modulated paraunitary filter banks given in references . Using these formulae, we can, directly, optimize the prototype filter coefficients in a quadratic form. A design example is also given to demonstrate these formulae in this paper. 展开更多
关键词 Quadratic constrained formula linear phase Perfect reconstruction Cosine modulated FB.
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A Construction Method of Wavelet with Linear Phase
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作者 匡正 李云晖 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 1997年第4期4-6,共3页
H(ω) |is chosen as a filter for filter H(ω) ,and |H(ω)| is a even function when H(ω) is a real coefficient rational function of e -iω ,and so the scaling and wavelet functions corresponding to | H... H(ω) |is chosen as a filter for filter H(ω) ,and |H(ω)| is a even function when H(ω) is a real coefficient rational function of e -iω ,and so the scaling and wavelet functions corresponding to | H(ω) | possess linear phases. An algorithm is given for computation of wavelet at very low cost. 展开更多
关键词 WAVELET SYMMETRIC WAVELET linear phase
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Linearization and analytic solution of fluid dynamics of cell two-phase flow
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作者 范天佑 范蕾 唐志毅 《Journal of Beijing Institute of Technology》 EI CAS 2011年第1期1-3,共3页
Linearized equations of fluid dynamics of cell two phase flow for one dimensional case are proposed. Based on the equations, an analytic solution is derived, in which the frequency of wave is observed. The frequency f... Linearized equations of fluid dynamics of cell two phase flow for one dimensional case are proposed. Based on the equations, an analytic solution is derived, in which the frequency of wave is observed. The frequency formula consists of all important parameters of the fluid dynamics. In our observation, the group velocity and phase velocity of the motion of wave propagation are explicitly exhibited as well. 展开更多
关键词 ell two phase flow fluid dynamics linearIZATION analytic solution
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Linear Complementary Method for Moving Boundary Problems with Phase Transformation 被引量:1
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作者 Deng Kang Shen Min(Shanghai University) Sun Huanchun(Dalian University of Technology) 《Advances in Manufacturing》 SCIE CAS 1998年第3期67-70,共4页
In this paper, the linear complementary method for moving boundary problems with phase transformation is presented, in which a pair of unknown vectors of heat source with phase transforming and the temperature field c... In this paper, the linear complementary method for moving boundary problems with phase transformation is presented, in which a pair of unknown vectors of heat source with phase transforming and the temperature field can be solved exactly, and a large amount of iterative calculations can be avoided. 展开更多
关键词 phase transformation moving boundary problems heat transfer linear complementary equation
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Two-Phase Multi Objective Fuzzy Linear Programming Approach for Sustainable Irrigation Planning
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作者 D. G. Regulwar Jyotiba B. Gurav 《Journal of Water Resource and Protection》 2013年第6期642-651,共10页
The objective of the present study is to develop the irrigation planning model and to apply the same in the form of Two-Phase Multi Objective Fuzzy Linear Programming (TPMOFLP) approach for crop planning in command ar... The objective of the present study is to develop the irrigation planning model and to apply the same in the form of Two-Phase Multi Objective Fuzzy Linear Programming (TPMOFLP) approach for crop planning in command area of Jayakwadi Project Stage I, Maharashtra State, India. The development of TPMOFLP model is on the basis of various Linear Programming (LP) models and Multi Objective Fuzzy Linear Programming (MOFLP) models, these models have been applied for maximization of the Net Benefits (NB), Crop production (CP), Employment Generation (EG) and Manure Utilization (MU) respectively. The significant increase in the value of level of satisfaction (λ) has been found from 0.58 to 0.65 by using the TPMOFLP approach as compare to that of MOFLP model based on maxmin approach. The two-phase approach solution provides NB = 1503.56 Million Rupees, CP = 335729.30 Tons, EG = 29.74 Million Man days and MU = 160233.70 Tons respectively. The proposed model will be helpful for the Decision Maker (DM) to take a decision under conflicting situation while planning for different conflicting objectives simultaneously and has potential to find out an integrated irrigation planning with prime consideration for economic, social and environmental issue. 展开更多
关键词 SUSTAINABLE IRRIGATION PLANNING Multi Objective Fuzzy linear PROGRAMMING Maxmin APPROACH TWO-phase APPROACH
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Comparative Study of Linear and Non-Linear Controls of Three-Phase Shunt Active Filters for Improving the Quality of Electrical Energy
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作者 Mamane Adamou Nabil Alkassoum +1 位作者 André Foulani Amadou Seidou Maiga 《Energy and Power Engineering》 2019年第3期149-166,共18页
The aim of this work is to comparatively study two types of control of a three-phase shunt active filter (TSAF) in order to realize a system of depollution of electrical networks so as to improve the quality of electr... The aim of this work is to comparatively study two types of control of a three-phase shunt active filter (TSAF) in order to realize a system of depollution of electrical networks so as to improve the quality of electrical energy. We used two TSA control models which differ in the method of disturbed currents detection, one linear and the other non-linear. The results show that the non-linear control method, although with high calculation blocks, gives more promising results than the linear control method. When connecting a non-linear load (televisions, lamps, variable speed drives, etc.) directly to the public distribution network, the non-linear nature of the load causes the source current to be deformed due to the presence of harmonic currents and voltages. These harmonics thus generate a high reactive power, and therefore considerable electrical losses in the network. One of the solutions to reduce losses on the electricity grid is to incorporate an electronic circuit called a filter into the electricity grid. This work carried out a comparative study of two types of control of a three-phase shunt active filter (TSAF) in order to carry out a system for cleaning up electricity networks in order to improve the quality of electrical energy. We used two TSA control models that differ in the method of detecting disturbed currents, one linear and the other non-linear. The results show that the non-linear control method, although with high calculation blocks, gives better results than the linear control method. 展开更多
关键词 Power QUALITY Active THREE-phase SHUNT Filter NON-linear CONTROL linear CONTROL
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Linear Phase FIR Filter on Measuring 3-D Surface
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作者 WANG Yunshan,YANG Fujun,LI Wei (Shandong University of Technology,Jinan 250061,CHN) 《Semiconductor Photonics and Technology》 CAS 1997年第2期29-34,共6页
An optical technology for 3-D surface measurement is set up.The technology,based on a deformed projected grating pattern which carries the 3-D information of the measured object,can automatically and accurately obtain... An optical technology for 3-D surface measurement is set up.The technology,based on a deformed projected grating pattern which carries the 3-D information of the measured object,can automatically and accurately obtain the phase map of a measured object by using a linear-phase FIR filter.In contrast to the 2-D fast Fourier transform technique,it’s more than fast.Only one image pattern is sufficient for measuring.The phase map can be processed without assigning fringe orders and making distinction between a depression and an elevation.Theoretical analysis and experimental result are presented. 展开更多
关键词 linear-phase FIR FILTER Profilometry Projected GRATING Image 3-D SURFACE
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计及边端效应的直线式移相变压器等效电路分析
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作者 赵镜红 周长朵 +2 位作者 王涵铭 严思念 严冬傲 《电工技术学报》 EI CSCD 北大核心 2024年第6期1792-1805,共14页
直线式移相变压器是一种新型移相变压器,具有绕组结构简单、易于模块化和可任意角度移相的优点。其直线型结构导致变压器存在边端效应,进而导致气隙磁场产生畸变。为了计算出边端效应产生的影响,该文从直线式移相变压器的磁场进行深入分... 直线式移相变压器是一种新型移相变压器,具有绕组结构简单、易于模块化和可任意角度移相的优点。其直线型结构导致变压器存在边端效应,进而导致气隙磁场产生畸变。为了计算出边端效应产生的影响,该文从直线式移相变压器的磁场进行深入分析,并建立计及边端效应的等效电路模型。首先,基于一维场理论对直线式移相变压器进行数学分析,根据场路复功率相等的原则,推导出等效电路二次侧参数,并计算出边端效应修正系数;然后,根据边端效应的分析结果和直线感应电机的等效电路拓扑建立计及边端效应的等效电路模型;最后,通过直线式移相变压器的二维有限元仿真模型和小功率样机的实验,验证了建模方法的合理性和等效电路模型的准确性。 展开更多
关键词 直线式移相变压器 边端效应 等效电路 有限元
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发卡式填充结构的直线式移相变压器设计及其磁场分析
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作者 赵镜红 薛婕 严思念 《国防科技大学学报》 EI CAS CSCD 北大核心 2024年第4期201-211,共11页
在原有直线式移相变压器的基础上,借鉴直线电机相关理论,设计了一款发卡式填充结构的直线式移相变压器,有效地解决了原有结构绕线方式复杂、体积大、不易进行模块化串并联等问题,同时改善了模块化连接时,连接处半填充槽引起的一次侧激... 在原有直线式移相变压器的基础上,借鉴直线电机相关理论,设计了一款发卡式填充结构的直线式移相变压器,有效地解决了原有结构绕线方式复杂、体积大、不易进行模块化串并联等问题,同时改善了模块化连接时,连接处半填充槽引起的一次侧激磁电流密度降低、气隙磁场畸变等问题。简要介绍了直线式移相变压器系统的工作原理;借鉴直线电机以及旋转电机设计方法,提出了半填充槽结构的直线式移相变压器的设计方法;同时采用了发卡式结构消除连接处半填充槽结构引起的一系列问题;最后通过有限元仿真进行验证对比。结果表明,对于所设计的发卡结构的直线式移相变压器,输出波形较好,气隙磁场畸变较小。 展开更多
关键词 直线式移相变压器 半填充槽 发卡式 磁场分析
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弱电网下光伏并网系统锁相环参数自适应控制 被引量:1
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作者 武海涛 张宁宁 +3 位作者 曹志轩 温素芳 李磊 李会珍 《电网与清洁能源》 CSCD 北大核心 2024年第1期52-61,共10页
针对弱电网下PLL(phase-looked loop,PLL)会使并网逆变器的稳定性下降问题,提出一种锁相环带宽自适应控制策略来实现锁相环参数依据电网实时阻抗值来获得最优的控制参数,保证系统最佳控制性能和稳定运行,从而提升跟网型逆变器在弱电网... 针对弱电网下PLL(phase-looked loop,PLL)会使并网逆变器的稳定性下降问题,提出一种锁相环带宽自适应控制策略来实现锁相环参数依据电网实时阻抗值来获得最优的控制参数,保证系统最佳控制性能和稳定运行,从而提升跟网型逆变器在弱电网下的对电网阻抗的适应能力。利用PSCAD/EMTDC进行仿真验证,仿真结果证明自适应控制策略正确、有效。 展开更多
关键词 弱电网 锁相环 谐波线性化 稳定边界 参数自适应
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基于虚拟电压矢量的双三相直线磁通切换永磁电机容错SVPWM策略
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作者 杜怿 严序康 +3 位作者 张丽 朱孝勇 毛怡 孙旭 《中国电机工程学报》 EI CSCD 北大核心 2024年第3期1153-1161,I0025,共10页
高可靠性是电梯驱动系统的首要指标。针对双三相直线磁通切换永磁(dual-three-phase linear flux switching permanent magnet,DTP-LFSPM)电机单相开路故障,提出一种基于虚拟电压矢量的容错空间矢量脉宽调制策略。首先,基于单相开路故... 高可靠性是电梯驱动系统的首要指标。针对双三相直线磁通切换永磁(dual-three-phase linear flux switching permanent magnet,DTP-LFSPM)电机单相开路故障,提出一种基于虚拟电压矢量的容错空间矢量脉宽调制策略。首先,基于单相开路故障下的五维变换矩阵计算得到故障后的32个空间电压矢量分布。然后,筛选部分空间电压矢量,以z子空间电压幅值为零且每个扇区产生对称的脉宽调制波形为目标,重构得到12个虚拟电压矢量,相邻的2个虚拟电压矢量都由3个基本电压矢量组成,并用于合成参考电压矢量,不仅可以减少单相开路故障容错控制时的电流谐波,而且具有计算简单,易于硬件实现等优点。最后,搭建DTP-LFSPM电机驱动控制系统仿真与实验平台,仿真和实验测试结果证明所提容错策略的正确性和有效性。 展开更多
关键词 双三相 直线电机 空间矢量脉宽调制 虚拟电压矢量 容错
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新型多功能厘米波频率合成器设计
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作者 莫馁 杨航 穆晓华 《压电与声光》 CAS 北大核心 2024年第2期171-173,共3页
该文介绍了一种新型多功能厘米波频率合成器,利用锁相倍频的方式,首次将直接数字频率合成器(DDS)输出的连续波(步进1 MHz)、常规脉冲、重频抖动、重频参差、双脉冲、捷变频信号、组变信号、二相编码和线性调频等信号搬移至0.8~18 GHz频... 该文介绍了一种新型多功能厘米波频率合成器,利用锁相倍频的方式,首次将直接数字频率合成器(DDS)输出的连续波(步进1 MHz)、常规脉冲、重频抖动、重频参差、双脉冲、捷变频信号、组变信号、二相编码和线性调频等信号搬移至0.8~18 GHz频段,外形尺寸为76 mm×70 mm×10 mm,体积约为传统类似频率综合器项目的1/20,具有工作频带宽、频率高、体积小等优点。 展开更多
关键词 频率合成器 线性调频 二相编码 宽频带 小体积
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固相萃取-超高效液相色谱-三重四极杆/线性离子阱质谱法检测水中大环内酯类抗生素
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作者 范素素 蔡萌 +2 位作者 方烨渟 王丽婕 石健 《分析科学学报》 CAS CSCD 北大核心 2024年第3期293-299,共7页
采用固相萃取-超高效液相色谱-三重四极杆线性离子阱质谱技术(SPE-UPLC-QTRAP MS)建立了环境水样中阿奇霉素、林可霉素、克林霉素、红霉素及替米考星5种大环内酯类抗生素的检测方法。调节水样pH为10后经HLB固相萃取柱净化、富集,然后用K... 采用固相萃取-超高效液相色谱-三重四极杆线性离子阱质谱技术(SPE-UPLC-QTRAP MS)建立了环境水样中阿奇霉素、林可霉素、克林霉素、红霉素及替米考星5种大环内酯类抗生素的检测方法。调节水样pH为10后经HLB固相萃取柱净化、富集,然后用Kinetex F5色谱柱进行分离,用0.1%甲酸水溶液和0.1%甲酸乙腈溶液进行洗脱,采用电喷雾正离子源(ESI+),多反应监测(MRM)-信息依赖采集(IDA)-增强子离子(EPI)扫描模式对样品进行检测,用多反应监测(MRM)进行定量,增强子离子(EPI)谱图库辅助定性。结果表明:5种大环内酯类抗生素线性关系良好,相关系数均大于0.9992;检出限为0.01~0.30μg·L^(-1),定量限为0.10~0.50μg·L^(-1);3种不同浓度的水样加标回收率为71.60%~111.05%,相对标准偏差均在10%以内,EPI谱库比对纯度值均大于90%。该方法将传统的MRM扫描模式结合EPI谱图库检索,实现了同时定性和定量分析,对未知物准确定性定量检测提供了重要参考。 展开更多
关键词 大环内酯类抗生素 固相萃取 线性离子阱 液质联用 残留检测
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