预测器-减法器-恢复器构成的滤波器去除刺激伪迹的研究

为了去除混在瞬态诱发耳声发射(TEOAE)信号中的刺激伪迹,同时保留瞬态诱发耳声发射信号的有效信息,本文首次提出将预测器-减法器-恢复器构成的滤波器,用于去除受试者耳中的刺激伪迹,来准确提取TEOAE信号。此方法与导出的非线性响应方法相比,不但能准确有效地去除刺激伪迹,而且能保留TEOAE信号的有效成分。是一种非常有前景的应用于临床的方法。     

北京谱仪桶部簇射计数器能量响应特性研究

在北京正负电子对撞机的J/ψ和Ds能区,选择了辐射巴巴事例,并以此来研究北京谱仪的桶部簇射计数器能量响应特性.在消除了由于电子和辐射光子在桶部簇射计数器中沉积能量区域重叠的影响后,正确地得到了桶部簇射计数器在电子和光子动量小于2GeV以下的能量响应,表明在所研究能区,桶部簇射计数器的能量响应线性很好.对桶部簇射计数器微小的非线性进行修正后,重建的π0不变质量谱得到改善.     

大能量钕玻璃棒状激光器新型热管理技术

 针对kJ级大能量钕玻璃固体脉冲激光器,对比研究了传统恒温水冷方式和采用加热控制的新型热管理技术下的激光棒温度分布情况。结果表明,采用新型热管理技术可大大降低棒内温度梯度,减小泵浦过程中的热效应,确保大能量激光输出;而且加热循环水的最佳升温值在单泵浦脉冲引起的激光棒平均温升值附近,使得径向温差最小,该最佳升温值与脉冲间隔时间有关,比如脉冲间隔15 s时,循环水在每个脉冲过后的最佳升温值为单泵浦脉冲引起的激光棒平均温升值的0.85倍;采用加热控制后水温和激光棒温度整体升高,因此在工作一个脉冲串后,必须恢复激光棒温度到初始状态,然后再进行下一个脉冲串工作。     

Two-dimensional particle-in-cell plasma source ion implantation of a prolate spheroid target

A two-dimensional particle-in-cell simulation is used to study the time-dependent evolution of the sheath surrounding a prolate spheroid target during a high voltage pulse in plasma source ion implantation. Our study shows that the potential contour lines pack more closely in the plasma sheath near the vertex of the major axis, i.e. where a thinner sheath is formed, and a non-uniform total ion dose distribution is incident along the surface of the prolate spheroid target due to the focusing of ions by the potential structure. Ion focusing takes place not only at the vertex of the major axis, where dense potential contour lines exist, but also at the vertex of the minor axis, where sparse contour lines exist. This results in two peaks of the received ion dose, locating at the vertices of the major and minor axes of the prolate spheroid target, and an ion dose valley, staying always between the vertices, rather than at the vertex of the minor axis.     

气体扩散方程解析解及在测定分子间势能的应用

设计了一新颖的分子动理论实验装置,根据求解在约束条件下的气体扩散方程的解析解和气体分子在升华时会对容器底部产生作用力的特点,设计了一种新颖简单的实验器材来测量分子间相互作用的势能,其实验曲线符合理论数据,误差分析后的补偿曲线所得结果可较为精确地与理论结果吻合。本实验常温下即可进行,且精度较高,适合快速材料性质测定及大学物理教学,以解决大学物理演示实验课关于学气体动理论的实验数量较少,且往往只涉及对热学微观过程的宏观模拟,而很少涉及气体动理论的实验,导致学生学习不够深入的问题。有利于学生对分子运动学问题的深入探索。     

离子液体萃取铂、钯和铑离子的研究进展

铂族金属作为一类不可再生资源,在工业和军工方面有着重要应用,但其在分配和供求上存在严重不均衡,凸显了其资源化回收再利用的重要性.离子液体作为一种性质优良的绿色溶剂,成为科学研究的热点.本文对近年来利用离子液体萃取铂族金属铂、钯和铑等的研究进行了综述,并对其未来的发展方向进行了展望.     

磁耦合Mn2+-Mn2+离子对发光行为研究进展

过渡金属Mn2+掺杂的半导体/绝缘体作为发光材料在照明、显示等领域具有重要应用.Mn2+离子具有5个未成对的d电子,掺杂在发光材料中通常具有高自旋态,其容易与近邻的Mn2+离子发生交换或超交换作用即磁相互作用.此类相互作用可在分子尺度下对电子自旋产生很强的束缚能力,使得磁耦合Mn2+-Mn2+离子对的发光行为不同于孤立...     

Hybrid Optoelectronic Bistability in Frequency-Domain and Its Potential Application in FBG Sensors

We propose a novel optical bistable device （OBD） in frequency-domain with which we can perform optical bistable operations in a number of fibre Bragg gratings （FBGs） which are included in the same OBD. Such an OBD may bring more opportunities in applications and, as an example, we show the possibility of using it in an FBG sensor demodulating system. By use of a tunable light source, consisting of a broad band source and a scanning fibre F-P （FFP）, we demonstrate the above-mentioned operations experimentally.     

Characterization of ZnO:AI films deposited by r.f.magnetron-sputtering at low temperature

Transparent conducting ZnO:AI thin films with good adhesion and Iow resistivity have been prepared on organic substrates and Coming 7059 glass substrates by r.f. magnetron-sputtering technique at Iow substrate temperature (25-210℃). Structural and photoelectric properties of the deposited films are investigated. The deposited films are polycrystalline with hexagonal structure and a preferred orientation with the c-axis perpendicular to the substrate. Only the (002) peak is observed.High quality films with resistivity as Iow as 1.0 x 10- 3Ω@ cm and 8.4 x 10- 4Ω@ cm, the average transmittance over 74% and 85% in the wavelength range of the visible spectrum have been obtained on different substrates.     

桥链七甲川菁的合成及光性能

菁是一种具有多功能用途的染料,除用作卤化银感光材料及有机光导材料的光谱增感剂、光记录材料中记录介质外,还可作为染料激光器中用的激光染料.我们曾合成了四甲川苯乙烯菁、五甲川(艹粦)及五甲川吡喃鎓等红外染料作为激光染料,测定了它们的光性能.本文合成了具有桥链的七甲川菁,研究了这些桥链七甲川菁的吸收光谱及荧光光谱,并以YAG激光倍频(532nm)作泵浦源,测定了它们的激光调谐范围、中心波长及激光转换效率.