3D electromagnetic simulation of the coupling characteristics and double-stub Ferrite tuners impedance matching for EAST ICRH four-strap antenna

A program developed with COMSOL software integrates EAST four-strap antenna coupling with the double-stub Ferrite tuners(FT)impedance matching,obtaining physical quantities crucial for predicting the overall performance of the ion cyclotron resonance heating(ICRH)antenna and matching system.These quantities encompass S-matrix,port complex impedance,reflection coefficients,electric field and voltage distribution,and optimal matching settings.In this study,we explore the relationship between S-matrix,reflection coefficients,port complex impedance,and frequency.Then,we analyze the impact of Faraday screens placement position and transparency,the distance from the Faraday screen(FS)to the current straps(CS),the relative distance between ports,and the characteristic impedance of the transmission line on the coupling characteristic impedance of the EAST ICRH system.Finally,we simulate the electric field distribution and voltage distribution of the EAST ICRH system for plasma heating with double-stub FT impedance matching.Using optimized parameters,the coupling power of the ICRH system can be approximately doubled.The results present herein may offer guidance for the design of high-power,long-pulse operation ICRH antenna systems.

Optical matching layer structures in evanescent coupling photodiodes at a wavelength of 1.55 μm:physics,design and simulation

We have studied the optical matching layers （OMLs） and external quantum efficiency in the evanescent coupling photodiodes （ECPDs） integrating a diluted waveguide as a fibre-to-waveguide coupler, by using the semi-vectorial beam propagation method （BPM）. The physical basis of OML has been identified, thereby a general designing rule of OML is developed in such a kind of photodiode. In addition, the external quantum efficiency and the polarization sensitivity versus the absorption and coupling length are analysed. With an optical matching layer, the absorption medium with a length of 30μm could absorb 90% of the incident light at 1.55μm wavelength, thus the total absorption increases more than 7 times over that of the photodiode without any optical matching layer.

STRESS AND ENERGY TRANSFER OF WATER COUPLING BLASTING

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考虑快速变负荷和灵活性供需匹配的耦合系统优化调度

可再生能源与快速变负荷改造的火电机组在同一并网点对外形成耦合系统,是提升沙漠、戈壁、荒漠等灵活性发电资源缺乏而可再生能源比例较高地区灵活性的有效手段。为了挖掘火电机组改造后的耦合系统经济性与灵活性,文中提出一种风光火耦合系统多目标优化调度方法。首先,根据实际测算的火电机组灵活性改造后的运行煤耗数据,拟合了机组爬坡过程的煤耗计算公式,并分析了火电快速变负荷能力提高对耦合系统经济性和灵活性的影响。在此基础上,将日综合运行收益与灵活性供需匹配度作为目标函数,考虑包括阶梯式爬坡率在内的系统运行约束,构建多目标优化调度模型。通过在优化算法中使用分组关联多项式变异算子,提高了算法对维度较高、约束较复杂的电力系统多目标优化调度问题的求解能力。最后,以某地区耦合系统为例进行了优化调度仿真。结果表明,文中所述方法能够获得综合经济性与灵活性相对更优的耦合系统优化调度方案。

普通铅对LA-ICP-MS磷灰石U-Pb定年结果的影响及校正方法

磷灰石是火成岩、变质岩和沉积岩中广泛分布的含铀矿物,开展磷灰石U-Pb年代学研究对揭示岩浆演化过程、示踪溯源等方面具有重要意义。激光剥蚀电感耦合等离子体质谱法(LA-ICP-MS)是开展磷灰石U-Pb年龄微区分析的重要手段之一。当前,基体匹配磷灰石U-Pb定年矿物标样缺乏和标样中不可避免的普通铅是制约LA-ICP-MS高精度磷灰石U-Pb年龄分析的主要瓶颈。本文对比研究了标样中普通铅对LA-ICP-MS磷灰石U-Pb定年结果的影响,采用含普通铅的磷灰石MAD作外标直接开展U-Pb年龄校正,获得的被测样品年龄会产生显著的系统偏差(最大约6%);采用207Pb法或Tera-Wasserburg图解法先校正标样中普通铅,再利用校正后的数据进行元素分馏和仪器漂移校正则可获得准确的磷灰石U-Pb年龄,与推荐值偏差在2%以内。另一方面,为消除标样中普通铅对分析结果的影响,本文还采用水蒸气辅助激光剥蚀方法,实现以NIST612玻璃作为外标准确分析磷灰石U-Pb年龄,解决了磷灰石U-Pb定年微区分析高质量标样缺乏的难题。本研究通过对标样中普通铅进行预校正或采用非基体匹配分析,建立了高精度LA-ICP-MS磷灰石U-Pb定年新方法,将促进磷灰石U-Pb年代学在地球科学研究中的应用。

电感耦合等离子体原子发射光谱法测定锆镍合金粉中锆

建立电感耦合等离子体原子发射光谱法测定锆镍合金粉中的锆含量。采用硝酸-氢氟酸溶解样品,选择339.198 nm谱线作为锆元素分析谱线,通过基体匹配法消除镍基体干扰。锆的质量分数在0.1%~40%范围内与光谱发射强度线性关系良好,相关系数为0.9997,方法检出限为0.0054%,定量限为0.018%。采用所建方法对锆镍合金模拟样品和锆镍合金粉样品进行测定,测定结果的相对标准偏差为0.208%~0.408%(n=11),样品加标回收率为98.9%~102.5%。该方法能够快速、准确地测定锆镍合金粉中的锆含量。

Parameters optimum matching of pure electric vehicle dual-mode coupling drive system

As an important development direction of pure electric vehicle drive system,the distributed drive system has the advantages of compact structure,high transmission efficiency,and flexible control,but there are some serious problems such as high performance requirements to the drive motors,complex control strategies,and poor reliability.To solve these problems,a two motors dual-mode coupling drive system has been developed at first,which not only has the capacity of two-speed gear shifting,but also can automatically switch between the distributed drive and the centralized drive by means of modes change control.So,the performance requirements to the drive motors can be reduced,the problem of abnormal running caused by the fault of unilateral distributed drive systems also can be resolved by replacing the drive mode with centralized drive.Then,the system parameters primary and the optimum matching under the principle of efficiency optimization have been carried out,which makes the drive system achieve predetermined functions and meet the actual demands of different operating statuses.At last,the economic comparison of a pure electric vehicle installation with a dual-mode coupling drive sytem,a single-motor centralized drive system or a dual-motor distributed drive system in the simulation conditions has been completed.Compared with other systems,the driving range of the electric vehicle driven by the designed system is significantly increased,which proves the better efficiency and application value of the system.

High-sensitivity methane monitoring based on quasi-fundamental mode matched continuous-wave cavity ring-down spectroscopy

Continuous-wave cavity ring-down spectroscopy(CW-CRDS)is an important technical means to monitor greenhouse gases in atmospheric environment.In this paper,a CW-CRDS system is built to meet the needs of atmospheric methane monitoring.The problem of mode matching is explained from the perspective of transverse mode and longitudinal mode,and the influence of laser injection efficiency on measurement precision is further analyzed.The results of cavity ring-down time measurement show that the measurement precision is higher when the laser is coupled with the fundamental mode.In the experiment,DFB laser is used to calibrate the system with standard methane concentration,and the measurement residual is less than±4×10^(-4)μs^(-1).The methane concentration in the air is monitored in real time for two days.The results show the consistency of the concentration changes over the two days,which further demonstrates the reliability of the system for the measurement of trace methane.By analyzing the influence of mode matching,it not only assists the adjustment of the optical path,but also further improves the sensitivity of the system measurement.

Linear theory of beam–wave interaction in double-slot coupled cavity travelling wave tube

A three-dimensional model of the double-slot coupled cavity slow-wave structure （CCSWS） with a solid round elec- tron beam for the beam-wave interaction is presented. Based on the ＂cold＂ dispersion, the ＂hot＂ dispersion equation is derived with the Maxwell equations by using the variable separation method and the field-matching method. Through numerical calculations, the effects of the electron beam parameters and the staggered angle between adjacent walls on the linear gain are analyzed.

Wireless Power Feeding with Strongly Coupled Magnetic Resonance for a Flying Object

Wireless power feeding was examined with strongly coupled magnetic resonance for an object moving in 3-D space. Electric power was transmitted from the ground to an electrically powered toy helicopter in the air. A lightweight receiver resonator was developed using copper foil. High Q of greater than 200 was obtained. One-side impedance matching the transmitter side was proposed to cope with high transmission efficiency and the receiver’s weight reduction. Results show that the efficiency drop near the ground was drastically improved. Moreover, the measured efficiency showed good agreement with theoretical predictions. A fully equipped helicopter of 6.56 g weight was lifted up with source power of about 5 W to an altitude of approximately 10 cm.

Apodized grating coupler using fully-etched nanostructures

A two-dimensional apodized grating coupler for interfacing between single-mode fiber and photonic circuit is demonstrated in order to bridge the mode gap between the grating coupler and optical fiber. The grating grooves of the grating couplers are realized by columns of fully etched nanostructures, which are utilized to digitally tailor the effective refractive index of each groove in order to obtain the Gaussian-like output diffractive mode and then enhance the coupling efficiency.Compared with that of the uniform grating coupler, the coupling efficiency of the apodized grating coupler is increased by 4.3% and 5.7%, respectively, for the nanoholes and nanorectangles as refractive index tunes layer.

Novel exact solutions of coupled nonlinear Schro¨dinger equations with time–space modulation

We construct various novel exact solutions of two coupled dynamical nonlinear Schrōdinger equations. Based on the similarity transformation, we reduce the coupled nonlinear Schrōdinger equations with time-and space-dependent potentials, nonlinearities, and gain or loss to the coupled dynamical nonlinear Schrrdinger equations. Some special types of non-travelling wave solutions, such as periodic, resonant, and quasiperiodically oscillating solitons, are used to exhibit the wave propagations by choosing some arbitrary functions. Our results show that the number of the localized wave of one component is always twice that of the other one. In addition, the stability analysis of the solutions is discussed numerically.

Effectiveness of Radiofrequency Inductively Coupled Plasma Sources for Space Propulsion

Evolution of geometric forms of antenna coils for radiofrequency(RF)inductively coupled plasma(ICP)sources is analyzed.Top effectiveness of flat ICPSs generating plasma"tablet"is shown.Especially effective are ICPSs using antenna coils enhanced with ferromagnetic cores(FMICPS).It is found that the design of flat ICPSs is simpler and more convenient for the arrangement of plasma diagnostics in comparison with ICPSs of other geometries.Effective flat FMICPS models of different diameters ranging from 10 cm to 100cm are considered.Recommendations are given for development engineers dealing with ICPS devices in general and with radio frequency ion thrusters(RITs)in particular.

基于倒L型匹配衰减器的宽带PLC信号阻抗匹配

针对窄带电力线通信(powerline communication, PLC)数据传输速率低、负载阻抗不匹配导致信号反射的问题,提出一种基于倒L型匹配衰减器的宽带PLC阻抗匹配方法。首先,基于归一化低通滤波器的频率变换、阻抗变换和电路变换方法,设计实现了三阶巴特沃斯T型宽带带通滤波模块。然后,采用倒L型结构的纯电阻匹配网络,通过确定不同频点的阻抗值调整主干匹配网络中可变电阻元件,实现了PLC耦合器与电力线之间的阻抗匹配。最后,根据提出的阻抗匹配方法设计制作了具有1~30 MHz带宽的PLC耦合电路。ADS仿真和实测验证均表明,所提阻抗匹配方法在更宽的频率范围内具备良好的匹配效果和电路参数易调节的特点,为PLC阻抗匹配的设计提供了新的理论和实践依据。

基于磁耦合谐振的多自由度电机无线电能传输

针对多自由度电机无线电能传输中传输效率较低的问题,提出基于磁耦合谐振的多自由度电机无线电能传输方法。该方法根据共振原理构建磁耦合谐振式无线电能传输模型,通过反射系数描述阻抗匹配状态,获取最佳负载阻抗;采用混沌优化算法优化电机线圈损耗率,实现多自由度电机无线电能传输优化。实验结果表明,应用该方法后,多自由度电机的电能输出功率达到了893 W,传输效率提升了0.10以上,提高了电能输出功率和传输效率,方法有效,具备可行性。

速调管放大器输入腔的匹配理论和模拟研究

基于输入微波与腔体耦合的等效电路模型,对于任意的腔体和电子束参数,建立了任意的输入微波与腔体耦合的速调管放大器输入腔的两种匹配状态的理论。建立了带有互感和电子束等效电阻和电容等参数的输入腔等效电路模型,推导了入射功率与反射功率的表达式,以及输入微波与带有电子束的输入腔耦合的完全匹配状态和任意的耦合这两种情形时输入功率和间隙电压关系的公式。推导了完全匹配状态时输入微波工作频率与输入腔有载品质因数的表达式。推导了复耦合系数等于1时输入腔外观品质因数与热腔品质因数的表达式,得出了当工作频率等于输入腔谐振频率,输入腔外观品质因数与热腔品质因数相等,且满足电子束等效电容远小于1时接近达到匹配状态,与传统理论基本一致。通过对比两种状态时的入射功率,得出了匹配状态时的入射功率小于复耦合系数等于1时入射功率的结论。通过对比复耦合系数等于1时新理论和传统理论的入射功率,得出不考虑电子束等效电容情况下两者相等的结论。采用二维粒子模拟的模型与匹配理论进行了对比,粒子模拟与理论基本一致。根据匹配理论找到了接近匹配状态的工作频率与有载品质因数以及较小的输入功率。

基于SAR阻抗匹配的WPT最大效率跟踪控制方法

无线电能传输(WPT)技术因其安全、便捷、非接触等优点而备受关注。最大效率传输是WPT系统中一个重要课题。传统的最大效率跟踪方法通常设定系统在固定耦合条件进行负载阻抗匹配,然而,耦合系数会在初级和次级线圈相对位置变化时不可避免地发生变化。提出基于耦合系数辨识与半有源整流(SAR)阻抗匹配的最大效率跟踪控制方法,该方法利用SAR结合耦合系数识别进行阻抗匹配,开关控制电容(SCC)补偿其阻抗虚部,避免了整流电路中非线性因素的影响。同时系统响应较快且控制方法便于实现。仿真和实验结果表明,耦合系数和等效负载变化时,都可以准确估计耦合系数并跟踪至最大效率点和输出恒压。

基于“人口—产业—治理”匹配度测算的我国城镇化空间优化策略探讨

随着我国城镇化进入中后期,城镇化空间发展要素不匹配、不协调的特征持续凸显。面对由此引发的各类问题,党的十八大以来,我国政府连续出台两轮新型城镇化规划,从系统视角提出了人口、产业、治理等要素协同配合的城镇化空间政策,为破解新时期城镇化面临的矛盾问题指明了方向。为推动城镇化空间政策的有序实施、优化提升城镇化各维度要素的协同发展,利用2020年“七普”全国297个地级及以上城市的统计数据构建指标体系,基于耦合协调度模型,测度城镇化与人口、产业、治理各维度的耦合协调水平,分析城镇化“人口—产业—治理”空间匹配度格局,识别发现我国现有城镇化空间匹配度格局呈现治理匹配度相对偏低、区域协调性有待增强、高匹配度新发展通道逐步形成、中小城市匹配度亟待提高。在此基础上,从坚持政策系统性、巩固完善总体空间布局、保障规模政策高效实施、强化特殊地区的针对性政策供给、建立政策动态调控机制等方面提出优化和推进城镇化空间政策实施的策略建议。

供需匹配视角下我国医疗资源耦合协调关系研究

目的:探讨医疗资源供给和医疗服务利用之间的耦合协调关系,为医疗资源合理配置提供有益参考。方法:以2017-2021年东中西部地区医疗资源供给和利用相关数据为基础,采用熵权法和耦合协调度模型,从供需匹配视角分析医疗资源供需耦合协调关系。结果:2017-2021年医疗资源供需总体耦合协调等级从初级协调升至中级协调,协调类型均为需求滞后型;东部地区2017-2021年医疗资源供需耦合协调度较中部和西部地区最高,协调类型均为供给滞后型;中部地区2017-2021年医疗资源供需耦合协调度较其他两个地区最低。结论:总体医疗资源供给得到明显提升,医疗资源配置耦合协调度稳步上升,但东中西部地区医疗资源配置存在较大差距。应从医疗资源供给端和需求端共同发力,构建医疗服务供需精准对接机制,探索医疗服务供需渐进决策路径。

考虑新能源爬坡的风光火耦合系统源荷匹配性分析及容量优化配置

风力发电、光伏发电与火力发电经同一点并网形成耦合系统,是我国北方地区发电侧灵活性调节电源与新能源间高效、低碳协同的一种形式.考虑区域新能源爬坡特性,结合源荷匹配分析,发掘和利用其规律,研究风光火耦合系统的容量优化配置方法,为耦合系统规划提供参考.首先,简述耦合系统运行模式和不确定性处理方法;其次,考虑耦合系统风光互补、爬坡事件和关键负荷特性,选取并提出相关指标用于源荷匹配评价;再次,考虑源荷特性、匹配、成本和收益等约束,建立耦合系统容量优化配置模型;最后,基于辽宁地区实际数据进行算例仿真,得到该地区耦合系统风、光的最优安装容量,并分析上述源荷相关因素与容量优化配置结果之间的相互影响,为新能源最优容量配置提供了参考与建议.