Y掺杂Al2O3高k栅介质薄膜的制备及性能研究

利用射频反应共溅射方法制备了Y掺杂Al₂O₃电介质薄膜，用掠入射x射线衍射检测了薄膜的结构，用高分辨率扫描电子显微镜(HRSEM)、原子力显微镜(AFM)观察了薄膜断面和表面形貌，用高频C-V和变频C-V及J-V测量了样品的电学特性. 结果表明，Y的掺入使电介质薄膜的介电常数k有了很大提高(8.14—11.8)，并体现出了较好的介电特性. 分析认为：与氧具有较大电负性差的Y离子的加入，增大了薄膜中的金属—氧键(M—O)的强度；同时，Y的加入使Al₂O₃的结构和原子配位发生了改变，从而提高了离子极化对薄膜介电常数的贡献. 退火前后的XRD谱均显示薄膜为非晶态；HRSEM断面和AFM形貌像显示所制备的薄膜非常平整，能够满足器件要求. 关键词： 高k栅介质 掺杂氧化铝 射频反应溅射     

激光光栅多普勒效应微小振动测量

为了提高测量微小振动的精度和动态范围，提出一种基于激光光栅多普勒效应的微振动测量系统。通过对差拍信号的频率分析，以峰值频率比值的方法可以排除干扰获得被测振动频率，找到振动的翻转点并判断振幅的大小；推导了在翻转点附近的微小位移与电压值的关系，对于小于计数当量值的位移由测量电压得到，提高了微小振动位移的测量精度以及系统测量的最小分辨率、动态范围。实验系统的频率范围为0．5～500Hz，振幅为20～10mm，相对误差小于1％，其动态范围大于100dB。     

Investigation of the intrinsic absorption edge in nanostructured polycrystalline zinc oxide thin films

We have studied the temperature variation of the intrinsic absorption edge of thin polycrystalline films of zinc oxide, obtained by high-frequency magnetron reactive sputtering. We ha ve observed that the intrinsic absorption edge in such films is described by a modified Urbach’s rule. We have calculated the effective frequency of phonons taking part in formation of the absorption edge. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 2, pp. 200–203, March–April, 2006.     

利用倒谱方法实现气声发育的重建

本文介绍了一种利用复倒谱来实现气声发音重建的方法。首先分析了气声发音的语音特征；进而在复倒谱序列中加入基频特征使其恢复到正常的语音。对元音［a］以及实际语音段进行了处理，均有较好的效果。     

Simple Millimeter Wave Dielectric Disc Filter with Very Flat Passband Characteristic

A particular fitter design suitable for millimeter- and submillimeter-waves is presented. By mounting equally spaced dielectric discs of identical thickness inside an overmoded circular waveguide very flat bandpass-filters with a relative bandwidth of about ±6% can be achieved. Normalized to the guided wavelength the air spacing corresponds to 1/4, 3/4, ... whereas the thickness of the dielectric disc is an integer multiple of 1/2. This particular design is possible for an odd number of discs only. A design example shows 19 GHz bandwidth at 150 GHz. A typical application is side-band filtering for radiometers at plasma experiments.     

双折射调谐器设计的等色图原理

提出双折射调谐器设计的等色图方法，给出原理。分析表明当晶片光轴处在以折射光线为轴线、顶角为４５°的圆锥面上时，双折射调谐器具有最快的波长调谐速率；当光轴位于过折射光线并与入射面成４５°或１３５°的平面内时，调谐器抑制非所需波长的能力最强。由此给出光轴相对晶片表面的两个优化取向，对石英晶片它们分别为１８．７１２°和５９．９２２°。文中还给出了三块晶片组合的调谐器的设计例子，对其调谐特性进行了简要的讨论。     

双折射双频激光器频差特性分析

用激光原理和晶体光学原理分析了腔内加旋光晶体输出光的频差特性，分析表明：当晶片旋转时，理论计算的频差永远小于晶体两本征模通过晶片位相差所决定的频差，有一特殊因子Ｇ＾２起作用。Ｇ＾２的物理意义是激光本征模在晶体两本征模上的投影比平方。这表明一个激光本征模在通过晶体时是部分以快模形式，部分以慢模形式，实际位相延迟介于两者之间，由于两者都介于快模和慢模之间，因而实际频差小于由快模和慢模决定的频差，理论计     

因瓦合金纳米微粉的恒磁导率及其压力、频率特性和压力相变

 以Fe-30wt%Ni合金片为母合金，用蒸发冷凝法制备了三种粗细不同的纳米微粒。经透射电镜和X光衍射物相分析，微粒成分与母合金一致。5T、5H和3K粉的平均粒度分别为13.6、27和40 mm。在室温和43~28个不同的流体静压力（0.000 1~2.205 GPa）下测量了它们的磁化曲线、磁导率曲线和起始磁化曲线。结果表明：（1）在H＝(20－132)(1000/4π)A/m范围内Fe-30Ni合金三种纳米粉均具有恒磁导率。（2）三种纳米粉恒磁导率随静水压的变化规律如下：μ_r＝3.83+0.253p-0.022 1p²-0.007 22p³（5T粉）；μ_r＝3.93+1.20p-1.97p²+1.52p³-0.510p⁴+0.059 9p⁵（5H粉）；μ_r＝5.96-0.276p+0.107p²-0.045 9p³（3K粉）。前两者随压力增加而升高。后者随压力增加而下降。（3）γ-α马氏体相变明显存在于5T、5H粉中，而3K粉中未见到。（4）Fe-30Ni合金片的μ_i从200kHz至2 MHz已下降一个数量级，而其纳米粉μ_i的频率范围高于300 MHz，增大两个数量级以上。     

Progress in stacked piezocomposite ultrasonic transducers for low frequency applications

A stacked ultrasonic transducer comprises multiple individual layers connected mechanically in series and electrically in parallel to reduce the fundamental thickness mode resonance to a frequency corresponding to the transit time of the complete stack and the electrical impedance to a value which corresponds to that of the layers of the stack in parallel. In turn, this allows lower frequency resonant operation than would be possible with a single layer, and facilitates electrical impedance matching to typical transmission circuitry. On transmission, an ideal stack of uniform layers will have an output amplitude larger than that of the equivalent single layer by a factor equal to the . However, using conventional signal amplification circuitry on reception, the output voltage amplitude will be smaller than that of the equivalent single layer by a similar factor. In the past, stacks have commonly been assembled from layers of conventional piezoceramic material but more recently there have been reports of stacks of 1–3 piezocomposites and it is this type that is considered here. The work described in this paper is motivated by the need to operate at frequencies lower than are possible using conventional piezocomposite fabrication technology. Progress in comparison of experimental and simulated results is outlined and the highlights of a theoretical design study are presented. These show that although the general behaviour of a stacked structure is easily predicted, a rigorous theoretical analysis is essential to understand the detail of even a limited range of possible designs.