毫米波行波管用衰减瓷

针对毫米波行波管用衰减瓷,就衰减瓷在复合粉体制备工艺、微观结构和材料性能测试等方面作了详细论述.     

含钛衰减陶瓷制作工艺

通过实验对现有衰减材料制作过程中的一些问题进行讨论 ,从微观结构、烧成工艺以及与国外衰减瓷几个方面的对比对衰减瓷的研制提出改进意见和建议。     

国内外几种衰减材料的制造工艺及结构性能比较

在电真空器件中广泛使用吸收微波的材料，随着器件功率增大，对此种材料的要求也越来越高，本文讨论了几种国外微波衰减瓷材料在结构性能和制造方面的特点，以及与几种国产衰减瓷材料的比较，对衰减瓷材料提出了主要要求；叙述了表征吸收微波电磁能量的参数和制造材料的物化原理。     

微波管用衰减材料的研究

首先介绍了国内外的几种微波衰减材料,同时分析了我所正在使用和研究的几种衰减瓷;其次介绍了波导传输反射法测量微波衰减材料的高频电磁参数,以及国内其它单位和国外的测量水平状况;再次,通过介绍衰减器微波吸收特性的CAD,对衰减瓷在使用中的不匹配问题进行了讨论;最后结合笔者的认识,讨论了今后微波管用衰减材料的研究方向。     

工艺参数对TiO2衰减瓷的影响

通过选择合理的工艺参数可提高TiO2衰减瓷的性能，实验表明通过在一定范围内升高温度、增加TiO2含量和添加高价态氧化物可提高TiO2衰减瓷的衰减量。     

钙钛矿瓷的半导化及其感湿机理

本文提出了钙钛矿瓷半导化的替位缺陷模型,并以此导出了半导瓷的电阻率公式。文中分析了钛铝酸钙瓷表面的吸附作用和感湿机理。文中还介绍了一种半导体瓷的极性检测法。     

连续激光作用下瓷质绝缘子温度和热应力分析

利用高能激光清除输电线路缠绕异物的方法取得了较好的使用效果,但激光在清除异物时也会照射到绝缘子上,时间过长可能会损伤绝缘子.为了研究在使用激光辐照瓷质绝缘子时的温度、应力损伤特性,本文对激光静止和移动辐照不同材料瓷绝缘子不同部位的情况进行了建模、计算,重点分析了瓷绝缘子在使用普通瓷、氧化铝瓷、氧化锆瓷、堇青石瓷四种材料...     

95%氧化铝瓷的烧成缺陷——暗斑问题的研究

本文通过几种测试方法和分析方法,系统地研究了暗斑瓷与正常瓷在宏观物理性能与微观结构方面所存在的差异。结果表明,暗斑瓷的介质损耗比正常瓷增加近二个数量级,抗折强度下降10%左右,在暗斑瓷中发现有次晶相钙长石和钙铝黄长石,而在正常瓷中,这二种次晶相的含量明显减少或基本上没有发现。95%氧化铝瓷中暗斑的产生与瓷体中次晶相钙长石和钙铝黄长石的出现有关,特别是钙长石的存在会大大增大瓷体的介质损耗,因此,具有暗斑缺陷的瓷件不应投入正常使用。     

RT瓷基体质量问题的研究

本文以国内外十余种氧化铝碳膜电阻瓷体的微观分析资料为据,从瓷体成分、晶相结构和表面缺陷三方面研究了影响瓷体渗碳质量的因素,认为目前国产瓷体中二次莫来石晶相发育不良是重要影响因素。文中对莫来石的存在状况与渗碳质量的关系做了简要分析,并以生产实例说明提高瓷体质量的主要措施。     

瓷绝缘子表面激光损伤的数值模拟和实验研究

为了防止输电线路激光除冰过程中激光损伤绝缘子等电力设备,采用有限元分析软件ANSYS对激光与普通瓷、氧化铝瓷、氧化锆瓷、堇青石瓷作用后的温度场和应力场进行了数值模拟,得到氧化铝瓷具有较好的抗热应力破坏性能,并进行了Nd∶ YAG激光照射绝缘子表面实验,得到绝缘子表面温度与照射时间和损伤类型的关系.结果表明,激光功率密度...     

Forced nonlinear precession of the magnetization vector under the conditions of an orientation transition

Forced nonlinear precession of the magnetization vector in a normally magnetized magnetic plate under the conditions of an orientation transition is considered. It is shown that, in the field lower than the form demagnetization field, the variable circularly polarized field causes precession of the equilibrium position of the magnetization vector. It is demonstrated based on a vector model in which the precession period of the equilibrium position is inversely proportional to the squared amplitude of the variable field and the sine of the angle of deviation of the equilibrium position of magnetization from the constant field. It is shown that the critical parameters necessary for excitation of precession of the equilibrium position are the amplitude and frequency of the variable field. Diagrams determining domains of existence of precession of the equilibrium position for different saturation magnetization of a magnetic plate are constructed in terms of the coordinates variable field amplitude-frequency. The role of dissipation of magnetization oscillations in the determination of the critical parameters is elucidated. The features of precession in the presence of asymmetric excitation and in the presence of anisotropy in the plane of the plate are noted.     

多光子Tavis-Cummings模型中运动原子与二项式光场相互作用的量子纠缠

利用全量子理论,研究了多光子Tavis-Cummings模型中运动原子与二项式光场相互作用系统的量子纠缠特性,讨论了不同初始状态下的二项式光场系数和原子运动速度对纠缠特性的影响.结果表明：二项式光场系数不影响场熵演化的周期性,但影响场熵峰值大小.随着原子跃迁光子数的增多,场熵演化的周期性和消纠缠现象逐渐消失.原子运动的速度影响场熵的演化周期,且影响场熵峰值的大小,而原子跃迁光子数的增大,会消弱原子运动速度对场熵演化的影响.当光场处于中间态,原子运动速度较低,且原子跃迁光子数较大时,光场与原子可以长久地处于量子纠缠态.     

有线电视加解密系统研究

有线电视加解密技术是有线电视付费管理的一个重要技术保障。在发射端,先将各路电视视频信号进行同步时基校准后,根据同步图案数据确定的同步图案实现每一路电视信号的同步信号的时基处理,以完成电视信号加密(加扰),随后将各路加密(加扰)电视信号连同数据的调制信号一起发送。在接收端,先根据射频信号解调出同步图案数据,并根据解调出的同步图案数据对射频信号进行群解密(解扰),从而实现了电视信号的单加群解。     

硬盘盘片结构特点及NiP基板CMP研究

分析了硬盘盘片的结构特点及硬盘基板的作用。在超净实验室中,通过调节氧化剂的含量,对硬盘基板进行了化学机械抛光。分析了不同氧化剂的含量对硬盘基板抛光速率的影响。对抛光后的硬盘基板进行了检测。抛光后的硬盘基板的粗糙度基本达到厂家的要求。对有可能造成硬盘基板划伤的原因进行了分析研究,为下一步解决划伤问题的实验提供了理论依据。     

Berechnungsmethoden zur Ermittlung der Schutzstrecke bei U- und Stadtbahnen

One essential component of project planning of train control system plants is the design and calculation of the protective route. At first, definitions of the most important terms are explained. There are three different calculation methods depending on the regard of the slope of the track system as well as on the train mass representable. The simplest method only considers the maximum slope before the signal and the danger point. The second method considers the slope of the track in the form of stairs. The gradient method is presented as a third method. The regard of the inclination gradient occurs here in the form of a twofold averaging. On the one hand the mean value in the form of an integral is formed via the train length. On the other hand averaging occurs in the form of an integral via the braking distance. The middle inclination value found in this way is inserted in the iterative process for the determination of the protective route.     

无驱动硅微机械陀螺

报道了无驱动结构硅微机械陀螺,推导了输出电压方程。从方程表达式可看出,该陀螺输出信号包含旋转载体的偏航和俯仰角速度及自旋角速度的信息。通过实验说明如何在输出信号中提取相关信息,即输出信号的频率表示载体自旋角速度的平均值,输出信号的包络表示载体偏航和俯仰角速度大小的瞬时值,输出信号的极性由输出波形的相位超前和滞后确定。最后给出该陀螺目前所达到的主要性能指标。     

基于红外测温的柜内元件热故障的反问题识别

结合红外辐射理论分别建立了控制柜内部单个和多个元件同时过热时对壳体内表面的红外辐射模型,得到了壳体内表面总的热流密度分布,并针对受热壳体建立二维热传导模型。基于对壳体表面红外成像测温,运用L-M算法进行了导热反问题模拟研究,对控制柜内部单个和多个元件的发热温度和方位进行了识别,最后分析了测量误差对计算结果的影响。结果发现运用L-M算法对单个和多个故障元件的发热温度和方位进行分开反演求解和同时进行反演计算时,都取得了较好效果,求解精度较高。测量误差对发热温度的反演计算结果影响更大。     

激光干扰行间转移CCD串扰现象研究

分析了激光功率密度增加到原来的10倍的时候,激光干扰行间转移CCD的串扰图像部分的灰度值并不是成比例地增加,并对串扰图像进行了仿真。由于光电二极管的溢出是不断进行的,垂直CCD的每个像元都获得所有超过阈值的像元溢出的光生载流子之和。每个超过阈值的像元溢出的光生载流子等于垂直CCD向下移动一个像元所需的时间内溢出的光生载流子。通过求解感光部分中光生电子遵守的方程,得到电子浓度增量和入射光功率的关系,进而仿真出串扰图像。仿真了激光能量为串扰阈值10倍和100倍量级时的串扰图像,仿真结果和实验结果可比。     

Phase-only synthesis of nulls in the sum and difference radiation patterns of the phased array antenna of a coordinate meter

Two approaches to the phase-only synthesis of nulls in radiation patterns (RPs) of the phased array antenna (PAA) of a coordinate meter are considered. The approaches use the specificity of the structure of the sheet of the measuring PAA. Such a PAA forms the sum RP and two difference RPs, which ensure measuring of the angular coordinates of an object. The problem of the phase-only synthesis of pattern nulls in prescribed directions in one or several PAA RPs with the angular orientation of the nulls of difference RPs kept in the RP scanning direction is solved. Design relationships are derived and a RP synthesis method, which is based on iterative univariate minimization of a nonlinear functional and includes analytic determination of the minimum of this functional at each iteration, is described. Examples of the array pattern synthesis are presented. The effect the phasing increment on the depth of formed nulls is analyzed and the dependence of the value of the PAA RP in the scanning direction on the position of the formed null is investigated. The effect of synthesized nulls on the shape of the PAA direction-finding characteristic is analyzed.     

A method for the measurement of the parameters of a two-layer stratified earth

A two-layer stratified model is assumed for the earth. The distances involved are assumed to be sufficiently short that the earth can be considered flat. The measurement of the parameters of the top layer can easily be made from the surface, but the parameters of the lower layer are somewhat more difficult. A method is given for the evaluation of these quantifies in terms of measurements of propagation between two antennas located at the surface of the earth. The theoretical solution for the field of an antenna located at the surface of a flat stratified earth has been given by J. R. Wait. This solution is taken as the starting point; it is put into a form which explicitly shows the influence of the parameters of the lower layer. The method of least squares is then used to evaluate the unknown parameters in terms of the measurements. This process allows the use of a large number of measurements which are essentially subjected to an averaging procedure. This prevents localized irregularities in the earth's surface from unduly affecting the results.