高压RESURF LDMOST的开态电阻与关态电压

降低表面电场原理可大大提高ＬＤＭＯＳＴ的器件性能。本文详细研究了用ＲＥＳＵＲＦ原理设计的ＬＤＭＯＳＴ的开态电阻与击穿电压的理论分析模型，并根据这一模型对ＲＥＳＵＲＦ ＬＤＭＯＳＴ的优化设计深入的讨论。最后评价了高压ＲＥＳＵＲＦ ＬＤＭＯＳＴ在保持器件耐压不变时降低其开态电阻的几种方法。     

FU－832F发射管的维护

ＦＵ－８３２Ｆ发射管的维护杨瑞田（锦州３１９转播台）目前，ＦＵ－８３２Ｆ发射管被广泛应用在中波１０ｋｗ发射机上，生产发射机的工厂采用ＦＵ－８３２Ｆ作单管功率放大。有些台站对原机实行改造时，也采用ＦＵ－８３２Ｆ取代并联工作的ＦＵ－１０１Ｆ做高频功率放大...     

THE OUTPUT OPTICAL FIELD INTENSITY DISTRIBUTION FORMED BY AN OPTICAL FIBER END

ＴＨＥＯＵＴＰＵＴＯＰＴＩＣＡＬＦＩＥＬＤＩＮＴＥＮＳＩＴＹＤＩＳＴＲＩＢＵＴＩＯＮＦＯＲＭＥＤＢＹＡＮＯＰＴＩＣＡＬＦＩＢＥＲＥＮＤ￥ＹＵＡＮＬｉ－Ｂｏ（Ｄｅｐａｒｔｍｅｎｔｏｆｐｈｙｓｉｃｓ，ＨａｒｂｉｎＥｎｇｉｎｅｅｒｉｎｇＵｎｉｖｅｒｓｉｔｙ...     

吸收光栅增益耦合DFB—LD电路模型

本文以激光器单模速率方程为基础,针对ＤＦＢ－ＬＤ推导了光子寿命与激光器内部损耗及端面出射损耗的关系,以及端面出射光功率与平均光子密度的关系,给出吸收光栅增益耦合ＤＦＢＬＤ电路模型,用该模型研究了ＡＧ－ＧＣ－ＤＦＢ－ＬＤ的自脉动效应及影响自脉动幅度和频率的主要因素。     

卫星在核爆炸探测中的应用

核爆探测通常指发现和测量核爆直接或间接产生的烟云、核电磁脉冲、光辐射、冲击波、地震波及雷达波等信号并进行处理,得出核爆的时间、地点、威力、方式及弹型等信息。     

高压RESURF LDMOSFET的实现

利用ＲＥＳＵＲＦ技术，使用常规低压集成电路工艺，实现了适用于ＨＶＩＣ、耐压达１０００Ｖ的ＬＤＭＯＳＦＥＴ。本文介绍了该高压ＬＥＭＯＳＦＥＴ的设计方法、器件结构、制造工艺测试结果，此外，本文还从实验和分析的角度探讨了覆盖在漂移区上面的金属栅－金属栅场板长度ＬＦ对ＲＥＳＵＲＦ器件耐压的影响。     

Pc5频段上电离层离子加热估值

本文利用欧洲非相干散射雷达的观测数据和地面同步测量的地磁脉动Ｐｃ５ＩＴＦＣ，ＥＳ ＥＴ ＸＷＹＧＸＭＷ ＩＨ Ｉ     

一个独特的FIFO接口子系统的设计

ＦＩＦＯ是数据处理经常用到的一个高速缓冲，可以说门类繁多，各种各样，文章介绍一种独特的ＦＩＦＯ接口子系统，在完成了本次读数操作之后，它使得ＦＩＦＯ自动地将下一单元数据输出到总线上，随时等待ＣＰＵ来读，并自动地继续上则不象常规作法那样去考虑ＣＰＵ繁琐的等待逻辑，另外该系统所有控制信号的产生均上一片ＧＡＬ２０ＲＡ１０和一片ＧＡＬ２０Ｖ８完成，该特点是基于可靠性和效费比的权稀考虑。     

新型陶瓷薄膜SOLUFILL生产多层陶瓷电容器

本文介绍一种介质陶恣薄膜商品ＳＯＬＵＦＩＬＬ的制造、工艺特点及特性。用ＳＯＬＵＦＩＬＬ生产ＭＬＣＣ有利于小型化、提高产品质量、降低成本，便于大规模生产瓷膜的专业化生产将是ＭＬＣＣ发展的一个方向。     

微波二极管变频器的频域分析

本文采用频域延拓交调波平衡法（ＦＤＣＩＢＭ）分析微波二极管变频器，讨论了本振（ＬＯ）和中频（ＩＦ）（或ＬＯ和射频（ＲＦ））输入均为大信号时的变频器分析，推导了上，下变频器统一的频域交调波平衡方程，并给出了一个微波巴伦二极管上变频器的分析和测量结果。     

The use of multistation networks in geomagnetic pulsation studies

Over the last few years, in association with the Ims,there has been a resurgence of interest in multistation studies of geomagnetic pulsations aimed at improving the understanding of generation and propagation processes. The spaced station networks may be entirely ground-based, a combination of ground and satellite stations or two or more satellites. One very important aspect in these studies is the measurement of the time delay of signals arriving at spaced stations. The standard techniques of cross-correlation and cross-spectral analyses are often employed and these methods are outlined. Consideration is given to the application of the methods to real data and to the limitations and accuracy of measurement. To illustrate these techniques details of the analysis of Pc 1 (0.2–5 Hz) geomagnetic pulsation ground-based spaced station data and results are presented.     

Influence of self-sustained pulsation in semiconductor lasers on optical transmission system

Degradations in semiconductor lasers caused by defects, such as dark lines or dark spots in an active region, sometimes introduce self-sustained pulsations. In this paper, dynamic properties of a modulated self-sustained pulsation InGaAsP/InP semiconductor laser are presented and the influence on the optical transmission system is described. In high-speed pulse modulation above the pulsation frequency, output waveforms showed a marked pattern effect. When the pulsing semiconductor laser is modulated below the pulsation frequency, the laser output had relatively large noise which had flat noise spectra. Therefore, error-rate characteristics were influenced by this noise. These results show that the self-sustained pulsations in semiconductor lasers sometimes cause transmission characteristics degradation on the optical transmission system. Therefore, careful attention should be paid to this matter.     

On the high-latitude limit of closed geomagnetic field lines

One ofthe investigations carried out with the energetic particle experiment on the Alouette satellites has been a study of the high-latitude boundary of 35-keV electrons in the outer radiation zone. A comparison of Λbthe average high-latitude boundary, with solar proton intensity versus latitude profiles, and with the location of the auroral oval, leads to the conclusion that Λbindicates approximately the high-latitude limit of closed geomagnetic field lines, or alternatively the low-latitude limit of open field lines. The dependence of Λbon local magnetic time and on the angle φ between the earth-sun line and the geomagnetic axis has been investigated. A noon-midnight asymmetry of about 8° is observed in Abas well as a marked dawn-dusk asymmetry. A dependence of Abon φ is also observed, in which Λbhas a minimum for φ ∼ 90° and is approximately symmetrical about this angle. The results are interpreted as indicating a stronger coupling between the solar wind and the magnetosphere when φ ∼ 90°, which results in more geomagnetic flux being swept back into the "tail" at these times. Some of the information included is presented in more detail in a recent paper by McDiarmid and Wilson [6].     

Comparison of Walsh and Fourier spectroscopy of geomagneticreversals and nonsinusoidal palaeoclimatic time series

Higher resolving capabilities and theoretical appropriateness of Walsh spectral techniques as compared to Fourier spectral analyses are presented for synthetic and nonsinusoidal geotime series. Theoretical developments of Walsh transform techniques and a comparative study of Walsh and Fourier spectral estimates are presented. The Walsh spectral technique is applied specifically to two actual time series data of geomagnetic reversals in binary telegraphic wave form and nonsinusoidal palaeomagnetic and palaeoclimate time series. Walsh spectra reveal periodicities in Milankovitch frequency bands and provide exceptionally well-resolved spectral lines. The possible physical significance of these orbital periodicities is discussed. A comparative example of autocorrelation analysis in the real time domain and dyadic time domain is also presented using a telegraphic signal model of actual geomagnetic reversal time series. and the result is briefly discussed. The computational efficiency of the Walsh function could be exploited further for many other binary and nonsinusoidal geophysical/geological time series     

基于地磁轨迹信号的新型室内定位

无处不在的地磁场由于室内环境中建筑结构的差异而具有独特的特征。此外,地磁信号的分辨难度会导致定位结果的不准确。本文提出了一种使用深度神经网络来提高定位精度的地磁室内定位系统。为了解决地磁场的低分辨率问题,本文将连续的地磁信号矢量化为轨迹序列,并以此为基础设计了一种新的地图构建方法来搭建用于室内定位的地磁数据库。然后,通过引入时间卷积网络(TCN)来提取磁轨迹序列的深层特征。实验结果表明,这种方法优于KNN和基于LSTM的DRNN等其他机器学习算法。      

Prompt nuclear EMP and Synchrotron radiation: a resolution of two approaches

The geomagnetic component of nuclear EMP generated by the prompt (t/sub max//spl sim/2 /spl mu/s) /spl gamma/-ray, neutron, and X-ray radiation from a nuclear explosion has been the subject of intense scrutiny for over 40 years. Recent work by certain members of the scientific community has suggested that a discrepancy exists in the calculations/derivation of nuclear EMP between treatments based on Maxwell's equations and the high-frequency approximation and those derived from a summation over particles emitting synchrotron radiation. In principle, the two approaches should be identical simply because the well-known Lie/spl acute/nard-Wiechert potentials for accelerating particles are derived from Maxwell's equations. In this paper, we start from the Lie/spl acute/nard-Wiechert potentials and derive an expression for nuclear EMP that is identical to previous work based on a solution of Maxwell's equations. Thus, the putative discrepancy between the two approaches is resolved and Maxwell's equations in this regard are again vindicated.     

Fault Tolerant and Minimum Loss Control of Double-Star Synchronous Machines Under Open Phase Conditions

In this paper, a new method for filtering the torque pulsations is proposed for double-star permanent magnet synchronous machines under fault conditions. The machine is supplied by two independent electric sources via two voltage source inverters. The proposed method deals with the case where an open-circuit fault occurs. To reduce the torque pulsations, the usual solution consists in supplying only the healthy star winding. Here, we propose to supply not only the healthy winding, but also the two remaining phases of the other star winding by the healthy legs of the faulty inverter. The stator current waveforms can be easily determined to minimize the copper losses while reducing the torque pulsations. Simulation and experimental results confirm the efficiency of the proposed method.     

Torque ripple minimization in PM synchronous motors using iterative learning control

Parasitic torque pulsations exist in permanent magnet synchronous motors (PMSMs) due to nonsinusoidal flux density distribution around the air-gap, errors in current measurements, and variable magnetic reluctance of the air-gap due to stator slots. These torque pulsations vary periodically with rotor position and are reflected as speed ripple, which degrades the PMSM drive performance, particularly at low speeds. Because of the periodic nature of torque ripple, iterative learning control (ILC) is intuitively an excellent choice for torque ripple minimization. In this paper, first we propose an ILC scheme implemented in time domain to reduce periodic torque pulsations. A forgetting factor is introduced in this scheme to increase the robustness of the algorithm against disturbance. However, this limits the extent to which torque pulsations can be suppressed. In order to eliminate this limitation, a modified ILC scheme implemented in frequency domain by means of Fourier series expansion is presented. Experimental evaluations of both proposed schemes are carried out on a DSP-controlled PMSM drive platform. Test results obtained demonstrate the effectiveness of the proposed control schemes in reducing torque ripple by a factor of approximately three under various operating conditions.     

基于遗传算法的地磁平缓区域导航算法

在地磁场信息变化平缓区域,采用单一特征量的相关算法进行匹配定位时误判率较高,为了解决这个问题,本文利用地磁场的矢量性提出一种基于遗传算法的地磁匹配搜索方法。 采用粗精匹配的方式对飞行器所在位置进行估计,再利用遗传算法逐步搜索最优匹配位置,从而解决在地磁场变化较为平缓区域定位导航容易误匹配的问题。最后根据所提算法进行了蒙特卡洛仿真实验,仿真结果证明该方法在地磁场平缓区域定位的有效性,同时具有较好的定位精度。