Numerical research of a 2D axial symmetry hybrid model for the radio-frequency ion thruster

Since the high efficiency discharge is critical to the radio-frequency ion thruster (RIT),a 2D axial symmetry hybrid model has been developed to study the plasma evolution of RIT.The fluid method and the drift energy correction of the electron energy distribution function (EEDF) are applied to the analysis of the RIT discharge.In the meantime,the PIC-MCC method is used to investigate the ion beam current extraction character for the plasma plume region.The beam current simulation results,with the hybrid model,agree well with the experimental results,and the error is lower than 11％,which shows the validity of the model.The further study shows there is an optimal ratio for the radio-frequency (RF) power and the beam current extraction power under the fixed RIT configuration.And the beam extraction efficiency will decrease when the discharge efficiency beyond a certain threshold (about 87 W).As the input parameters of the hybrid model are all the design values,it can be directly used to the optimum design for other kinds of RITs and radio-frequency ion sources.     

一种高精度多径延时分布估计算法的研究

使用传统PN码序列相关法所测得的多径延时的时域分辨率受到PN码片长度的限制。本文研究了一种高精度的PN相关算法,这种方法改进了传统的PN相关算法的时域分辨率。该方法依靠分解延时分布数据向量相关矩阵的特征向量空间,来得到多径传播的路径数目和高分辨率的延时分布。计算机仿真表明,该算法可以分辨出延时差在1／10码片级的两条传播路径。     

Study of beam divergence and thrust vector eccentricity characteristics of the Hall thruster based on dual Faraday probe array planes and its applications

The accurate knowledge of the thrust vector eccentricity and beam divergence characteristics of Hall thrusters are of significant engineering value for the beneficial integration and successful application of Hall thrusters on spacecraft. For the characteristics of the plume bipolar diffusion due to the annular discharge channel of the Hall thruster, a Gaussian-fitted method for thrust vector deviation angle and beam divergence of Hall thrusters based on dual Faraday probe array planes was propo...     

电站锅炉火焰检测器应用现状分析

文中介绍了电站锅炉使用的各类火焰检测器的原理、存在的问题及发展方向，为火电厂火焰检测器的选型提供依据。     

高功率空间电推进技术发展研究

面向未来深空探测、空间货运等空间任务对具有牛级大推力、数千秒比冲、数万小时寿命等性能高功率电推进技术的应用需求,通过调研对比分析的方式,详细论述了国内外高功率电推进技术的发展现状和趋势,并针对具体技术路线给出了展望.从高功率电推进技术发展和工程应用的角度,总结梳理了磁场拓扑结构设计与优化、系统效率提升、地面性能诊断测试...     

大跨度钢箱梁转体桥施工技术

本文青岛新机场高速连接线(双埠—夏庄段)工程(天康路以西段)(起点—K7+380)3标段的涉铁工程钢箱梁转体桥为背景,总结分析以往大跨度钢箱梁T构转体桥在球铰安装、转体准备工作、转体监控等方面的施工技术,详细叙述了大跨度钢箱梁转体施工,形成了一套比较完整的施工技术和工艺,为类似工程提供经验借鉴.     

精甲醇改直送方案可行性分析探讨

某石化公司精甲醇互供料系统中,精甲醇储罐无VOCs治理措施和安全泄压装置,罐区VOCs异味管控困难,产品采出液位调节阀失控,存在超压撕裂损坏风险。该文结合目前公司精甲醇互供料现状,从甲醇互供料系统流程入手,探讨通过增加技改技措,将精馏塔馏出口产品进装置精甲醇储槽后外送,改为直接通过外送管线送入储运二部北罐区甲醇储罐,减少中间送料过程,降低动力消耗,有效消除甲醇罐区VOCs治理隐患和储罐超压风险,同时减少互供料协调联系等诸多环节,降低了操作人员的工作量。     

Mode-Coupling Analysis of Parametric Decay Instability in Magnetized Plasmas

In this paper, derived from Maxwell and fluid equations of plasmas, unified nonlinear wave equations are used to describe the parametric decay instability （PDI） in magnetized plasmas, and in view of mode-coupling, we can obtain all the possible PDI channels. By solving the nonlinear equations with a mode-coupling method, we obtain the growth rate of the PDI, of which all of the three waves are ordinary mode （O-mode） or extraordinary mode （X-mode） wave. Under the dipole approximation, an explicit formula of the growth rate of the X-mode and the condition of the equilibrium density scale are obtained. According to the existence conditions of three X-mode waves, this kind of instability might exist in ECRH with the second harmonic X-mode wave.     

ECS系统在蒙华海电的应用

介绍了蒙华海电2×200MW机组ECS系统,分析了存在的问题,并给出了改进方法。     

C~4ISR网络对抗技术

攻击和防御是对抗的两个基本方面。文章首先阐述了C^4ISR的概念,然后对信息网络的对抗技术进行了归纳分类,讨论了各种信息网络防御机制,重点分析了不同防御机制中所存在的脆弱性,并提出了相应的攻击措施。最后,对C^4ISR网络对抗机制间的攻防关系进行了总结。