掺氮TiO2光学薄膜的吸光特性研究

TiO2在光催化方面具有较好的应用前景,可望用于有害污染物的降解处理;但由于其禁带宽度对应的激发波长在紫外区,限制了其大规模应用。文章利用操作简便、易于控制的真空阴极电弧离子镀膜技术,制备了非掺氮和掺氮的TiO2薄膜。并分别在300℃和500℃退火后,获得了非晶态向锐钛矿结晶的转变。结果还表明,掺氮TiO2薄膜的相变温度比非掺氮的TiO2薄膜要高,其光吸收区也从紫外区扩展到了可见光区。     

基于旋转机械故障诊断模糊神经网络多传感器融合(英文)

目前多传感器融合技术能够有效地提高精度和容错能力 ,所以它广泛应用于目标识别领域中。本文描述了一种基于旋转机械故障诊断多传感器融合系统 ,在数据融合处理中利用模糊神经网络 ,比较了采用基于数据融合实验结果和没有融合的原始数据 ,显然前者比后者更精确。     

大孔阴离子交换树脂的制备和性质

离子交换法是从矿浆中提取金属的主要方法之一.介绍了一种用于从真实氰化矿浆中提取金的带有两种弱碱官能团的新型大孔阴离子交换树脂的合成方法,并研究了交联度和胺化反应条件对树脂提金性能的影响.树脂对金的交换容量为16mg/g干树脂,树脂对金的选择性为1.1.与苏联制造的提金树脂相比,新型大孔阴离子交换树脂具有好的性能和良好应用前景.      

锂离子电池单离子导体聚合物电解质研究进展

锂离子电池在3C电子产品和动力汽车电池行业广泛应用,在航天电源领域也展现出一定的前景。单离子导体是基本仅由参与电化学反应的锂离子迁移的电解质体系,解决传统锂离子电池液态电解质存在的副反应和阴离子的浓差极化等问题,改善电池的库伦效率和循环寿命。研究者们发展了多种类型的单离子导体电解质。本文总结了近5年来不同阴离子类型的单离子导体聚合物电解质合成策略以及分子动力学模拟计算的最新进展。     

四极－十六极分区式线型阱中汞离子囚禁仿真研究

利用SIMION软件建立了四极-十六极分区式线型离子阱系统模型，在此基础上仿真模拟了汞离子在四极阱和十六极阱中被囚禁时的第一稳定区，并分析了离子在不同阱中的运动特性。研究了汞离子云在分区式阱中的囚禁体积和速度分布，以及在不同囚禁区域之间的穿梭过程。模拟得出了稳态情况下分区式阱中不同囚禁区域的粒子数密度分布，验证了分区式离子阱中离子云被连续囚禁、穿梭时粒子数衰减和补偿。同时，根据以上数据分析讨论了汞离子囚禁时的多普勒效应，估算了基于此分区式离子阱的汞离子微波钟的性能水平。     

Characterization of the low latitude plasma density irregularities observed using C/NOFS and SCINDA data

Complex electrodynamic processes over the low latitude region often result in post sunset plasma density irregularities which degrade satellite communication and navigation. In order to forecast the density irregularities, their occurrence time, duration and location need to be quantified. Data from the Communication/Navigation Outage Forecasting System (C/NOFS) satellite was used to characterize the low latitude ion density irregularities from 2011 to 2013. This was supported by ground based data from the SCIntillation Network Decision Aid (SCINDA) receivers at Makerere (Geographic coordinate 32.6°E, 0.3°N, and dip latitude ?9.3°N) and Nairobi (Geographic coordinate 36.8°E, ?1.3°N, and dip latitude ?10.8°N). The results show that irregularities in ion density have a daily pattern with peaks from 20:00 to 24:00 Local Time (LT). Scintillation activity at L band and VHF over East Africa peaked in 2011 and 2012 from 20:00 to 24:00 LT, though in many cases scintillation at VHF persisted longer than that at L band. A longitudinal pattern in ion density irregularity occurrence was observed with peaks over 135–180°E and 270–300°E. The likelihood of ion density irregularity occurrence decreased with increasing altitude. Analysis of C/NOFS zonal ion drift velocities showed that the largest nighttime and daytime drifts were in 270–300°E and 300–330°E longitude regions respectively. Zonal irregularity drift velocities over East Africa were for the first time estimated from L-band scintillation indices. The results show that the velocity of plasma density irregularities in 2011 and 2012 varied daily, and hourly in the range of 50–150 m s^?1. The zonal drift velocity estimates from the L-band scintillation indices had good positive correlation with the zonal drift velocities derived from VHF receivers by the spaced receiver technique.     

Effects of adiabaticity and non-adiabaticity of dust charge fluctuation on the propagation of the dust ion acoustic waves in inhomogeneous dusty plasma

A theoretical investigation has been made for adiabatic positive and negative dust charge fluctuations on the propagation of dust-ion acoustic waves (DIAWs) in a weakly inhomogeneous, collisionless, unmagnetized dusty plasmas consisting of cold positive ions, stationary positively and negatively charged dust particles and isothermal electrons. The reductive perturbation method is employed to reduce the basic set of fluid equations to the variable coefficients Korteweg–de Vries (KdV) equation. Either compressive or rarefactive solitons are shown to exist depending on the critical value of the ion density, which in turn, depends on the inhomogeneous distribution of the ion. The dissipative effects of non-adiabatic dust charge variation has been studied which cause generation of dust ion acoustic shock waves governed by KdV-Burger (KdVB) equation. The results of the present investigation may be applicable to some dusty plasma environments, such as dusty plasma existing in polar mesosphere region.     

Cassini Plasma Spectrometer Investigation

The Cassini Plasma Spectrometer (CAPS) will make comprehensive three-dimensional mass-resolved measurements of the full variety of plasma phenomena found in Saturn’s magnetosphere. Our fundamental scientific goals are to understand the nature of saturnian plasmas primarily their sources of ionization, and the means by which they are accelerated, transported, and lost. In so doing the CAPS investigation will contribute to understanding Saturn’s magnetosphere and its complex interactions with Titan, the icy satellites and rings, Saturn’s ionosphere and aurora, and the solar wind. Our design approach meets these goals by emphasizing two complementary types of measurements: high-time resolution velocity distributions of electrons and all major ion species; and lower-time resolution, high-mass resolution spectra of all ion species. The CAPS instrument is made up of three sensors: the Electron Spectrometer (ELS), the Ion Beam Spectrometer (IBS), and the Ion Mass Spectrometer (IMS). The ELS measures the velocity distribution of electrons from 0.6 eV to 28,250 keV, a range that permits coverage of thermal electrons found at Titan and near the ring plane as well as more energetic trapped electrons and auroral particles. The IBS measures ion velocity distributions with very high angular and energy resolution from 1 eV to 49,800 keV. It is specially designed to measure sharply defined ion beams expected in the solar wind at 9.5 AU, highly directional rammed ion fluxes encountered in Titan’s ionosphere, and anticipated field-aligned auroral fluxes. The IMS is designed to measure the composition of hot, diffuse magnetospheric plasmas and low-concentration ion species 1 eV to 50,280 eV with an atomic resolution M/ΔM ∼70 and, for certain molecules, (such asN ₂ ⁺ and CO⁺), effective resolution as high as ∼2500. The three sensors are mounted on a motor-driven actuator that rotates the entire instrument over approximately one-half of the sky every 3 min.This revised version was published online in July 2005 with a corrected cover date.     

马尔科夫尼可夫规则机理的讨论

不对称烯烃与不对称试剂进行亲电加成反应时,遵守马尔科夫尼可夫规则,本文从生成碳正离子和环状高价正离子的两种反应途径对其反应机理加以讨论,并指出决定两种途径的主要因素.     

IMF Direction Derived from Cycloid-Like Ion Distributions Observed by Mars Express

Although the Mars Express (MEX) does not carry a magnetometer, it is in principle possible to derive the interplanetary magnetic field (IMF) orientation from the three dimensional velocity distribution of pick-up ions measured by the Ion Mass Analyser (IMA) on board MEX because pick-up ions' orbits, in velocity phase space, are expected to gyrate around the IMF when the IMF is relatively uniform on a scale larger than the proton gyroradius. During bow shock outbound crossings, MEX often observed cycloid distributions (two dimensional partial ring distributions in velocity phase space) of protons in a narrow channel of the IMA detector (only one azimuth for many polar angles). We show two such examples. Three different methods are used to derive the IMF orientation from the observed cycloid distributions. One method is intuitive (intuitive method), while the others derive the minimum variance direction of the velocity vectors for the observed ring ions. These velocity vectors are selected either manually (manual method) or automatically using simple filters (automatic method). While the intuitive method and the manual method provide similar IMF orientations by which the observed cycloid distribution is well arranged into a partial circle (representing gyration) and constant parallel velocity, the automatic method failed to arrange the data to the degree of the manual method, yielding about a 30° offset in the estimated IMF direction. The uncertainty of the derived IMF orientation is strongly affected by the instrument resolution. The source population for these ring distributions is most likely newly ionized hydrogen atoms, which are picked up by the solar wind.