半浮区液桥自由面振荡特征

使用一套双路同步显微放大录像及图像处理系统,研究了夹角为90°的两个竖直剖面沿轴向不同高度液桥自由表面的位移振荡,得到轴向不同高度上的环向相位差,观测到在振荡周期内液桥表面轮廓线在不同时刻均不相交的特点。实验结果表明,液桥自由面振荡除具有径向扰动及轴向振荡变化外,还存在环向波动变化。根据实验结果,讨论了环向波动基本变化规律以及本实验在测量精度和测量误差方面存在的问题。     

测量结果的不确定度

不确定度是测量质量的重要指标。根据测量分布,提出了两类不确定度的评定方法,阐明了合成不确定度与总不确定度的计算和性质,并举出了应用例子。     

碱性体系锌—镍合金电沉积的研究

本文介绍了一种新型的碱性体系锌-镍合金电镀工艺。本工艺镀层光亮、镀液稳定、组成简单及维护方便,能在很宽的工艺范围下能镀出含镍量为11～15％的锌-镍合金。镀层具有高耐蚀性及低氢脆性。对电沉积机理也作了必要叙述。     

Acceleration of interplanetary pick-up ions and anomalous cosmic rays

It may not be doubted anymore that anomalous cosmic rays (ACRs) are produced in the heliosphere from interplanetary pick-up ions through their acceleration at the solar wind termination shock. However, there is no general agreement in the community of heliospheric researchers concerning the mechanism of injection of the pick-up ions into the shock acceleration. We discuss here three possible ways for pick-up ions to be involved into the acceleration process at the termination shock: (1) preacceleration of pick-up ions in the whole region from the Sun up to the termination shock by solar wind turbulences and interplanetary shock waves, (2) local preacceleration of pick-up ions in a vicinity of the termination shock by shock surfing, and (3) formation of high-velocity tails in pick-up ion spectra consisting of secondary pick-up ions which are produced in the supersonic solar wind due to ionization of energetic neutral atoms entering from the inner heliosheath.     

A survey of radio jets with Chandra and HST

Relativistic jets are a common property of radio-loud Active Galactic Nuclei (AGN). Understanding jet physical properties is an essential precursor to understanding the mechanisms of energy transport, and ultimately, how energy is extracted from the central black hole. In this paper, I highlight recent developments from Chandra and HST observations of kpc-scale jets in AGN, with particular emphasis on our survey of 17 radio jets in a sample of FRII radio galaxies. These observations show that (1) X-ray and optical emission is common from kpc-scale jets, (2) a large fraction of the bolometric luminosity is emitted at X-rays, and (3) in most sources, a candidate emission process for the X-rays is inverse Compton scattering of the Cosmic Microwave Background off the relativistic electrons in the jet. If the latter scenario holds, the implication is that jets are still relativistic on kpc scales.     

基于连续覆盖特性分析的星座设计

研究了需要对地面目标进行连续覆盖的星座的设计问题．首先推导了对覆盖性能有重要影响的星间覆盖间隔时间和轨道面覆盖间隔时间的计算公式，通过算例针对不同配置的星座进行了计算，使用工程仿真软件STK验证了分析结果．通过理论分析、算例计算以及工程仿真为该类型星座设计提供了理论指导。     

钛合金胶接点焊接头的性能检测

研究了不同焊接电流下钛合金板胶接点焊接头的A扫描信号和C扫描图像特征,并进行了拉伸-剪切试验。结果表明:通过观察C扫描图像的特征与A扫描信号的变化,能够划分胶接点焊接头的胶层区、热影响区、熔合区、熔核区以及焊接缺陷;随着电流(7~10 k A)的逐渐增大,接头熔核直径呈递增趋势,相应的失效载荷从7 231.5增加到10 939.0 N;当电流为7 k A时,在C扫描图像上反映出飞溅缺陷,此时接头失效载荷远小于没有出现飞溅的接头,可见飞溅降低了胶接点焊接头的拉剪载荷。     

Online scheduling of distributed Earth observation satellite system under rigid communication constraints

This paper focused on online scheduling of distributed Earth observation satellite system in a dynamic environment. The objective was to maximize the total profit of the overall system by efficiently coordinating the different satellites with stochastic arrival of urgent tasks, subject to rigid communication and observation time window constraints. We formulated this problem as a single-task, single-robot, time-extended assignment problem with intra-schedule dependency using the multi-robot task assignment taxonomy and formulated the sub-problem after releasing urgent tasks in a mixed-integer linear programming model. We first described the online scheduling algorithm for a single satellite, then we proposed the modified consensus-based bundle algorithm (m-CBBA) and modified asynchronous consensus-based bundle algorithm (m-ACBBA) with synchronous and asynchronous communication, respectively. Compared with initial versions of CBBA and ACBBA, the modified versions added the communication loop prediction phases to efficiently utilize scarce communication opportunities and reduce the communication requirements. Additionally, we introduce two contract net protocol (CNP)-based algorithms for comparison, respectively SingleItem-CNP-based (SI-CNP) algorithm and Batch-CNP-based (BA-CNP) algorithm. Computational experiments indicated that both the total profit and percentage of scheduled urgent tasks achieved by the m-ACBBA and m-CBBA algorithms were much higher than those achieved by both SI-CNP and BA-CNP. Additionally, the number of communications needed by either m-ACBBA or m-CBBA algorithm was lower than that by SI-CNP. When the communication cost in the system is high, the m-CBBA algorithm is preferred because it balances the profit and the required number of communications. When the communication cost is low, the m-ACBBA algorithm is preferred because it achieves high total profit and high percentage of scheduled urgent tasks.     

大厚度比零件（外侧）和波纹管（内侧）的缝焊研究

某重点型号波纹管组合件的设计要求是缝焊，对照以往产品的结构，比较明显的情况是波纹管在零件的内侧。零件的厚度是3mm，波纹管的厚度是0.1mm，零件与波纹管的厚度比比较大。波纹管在零件的内侧会产生一个问题：波纹管在焊接过程中会逐渐收缩，到最后与零件之间产生间隙，导致局部形不成焊缝。研究通过减小车配间隙,增加冷却手段、滚轮厚度和压力等措施来实现大厚度比的零件和波纹管之间的缝焊。     

Study of GNSS-measured ionospheric total electron content variations generated by powerful HF-heating

The purpose of this work is to report the experimental evidences for the influence of perturbations in the electron density in the dayside mid-latitude ionosphere, that are caused by high-frequency heating of the F2 layer, on the GNSS signals. The experiments were carried out at the Sura heater (Radio Physical Research Institute, N. Novgorod). During the sessions of ionospheric heating with different time modulations of the radiated power the rays linking the navigational satellites with the ground receiver intersected the heated region. Variations in the total electron content (TEC) were studied; these variations are proportional to the reduced phases of navigational signals. It is shown that with the square-wave modulation of the radiated power (with periods of 1, 6, 10 and 15 min), perturbations with periods of the main modulation of heating and its harmonics appear in the spectrum of TEC variations. Examples are presented of identification of the heating-induced variations in TEC, including determination of the amplitudes and time characteristics of these variations.