基于声门波和声道特征的语音情感识别

语音情感识别是实现自然人机交互不可缺失的部分,是人工智能的重要组成部分。发音器官的调控引起情感语音声学特征的差异,从而被感知到不同的情感。传统的语音情感识别只是针对语音信号中的声学特征或听觉特征进行情感分类,忽略了声门波和声道等发音特征对情感感知的重要作用。在我们前期工作中,理论分析了声门波和声道形状对感知情感的重要影响,但未将声门波与声道特征用于语音情感识别。因此,本文从语音生成的角度重新探讨了声门波与声道特征对语音情感识别的可能性,提出一种基于源-滤波器模型的声门波和声道特征语音情感识别方法。首先,利用Liljencrants-Fant和Auto-Regressive eXogenous(ARX-LF)模型从语音信号中分离出情感语音的声门波和声道特征;然后,将分离出的声门波和声道特征送入双向门控循环单元（BiGRU）进行情感识别分类任务。在公开的情感数据集IEMOCAP上进行了情感识别验证,实验结果证明了声门波和声道特征可以有效的区分情感,且情感识别性能优于一些传统特征。本文从发音相关的声门波与声道研究语音情感识别,为语音情感识别技术提供了一种新思路。     

稀疏拉伸式L型极化敏感阵列的二维波达方向和极化参数联合估计

为降低现有的共心式矢量传感器阵列天线间存在的严重互耦影响,进一步提高参数估计精度,该文提出一种稀疏拉伸式L型极化敏感阵列(SSL-PSA),并针对该阵列提出一种2维波达方向(DOA)和极化参数联合估计算法。首先建立稀疏拉伸式极化敏感阵列的信号模型,然后将阵列划分为6个子阵,采用子空间旋转不变算法(ESPRIT)算法得到多个旋转不变因子(RIFs),再根据旋转不变因子间的关系,通过数学运算,得到一组方向余弦有模糊精估计值和4组无模糊粗估计值;然后重构出对应的4组导向矢量,根据导向矢量和噪声子空间的正交性,确定出正确的一组无模糊粗估计值;最后通过现有的解模糊方法得到高精度且无模糊的DOA和极化参数估计值。该文所提阵列不存在共心结构,相对于现有的含有共心式矢量传感器结构的阵列,大大降低了互耦影响,且可在不增加天线数目的前提下,有效扩展阵列的2维孔径,大大提高DOA估计精度。仿真结果证明该文所提方法的有效性。

     

电子探针在新疆拜城碱性花岗岩烧绿石研究中的应用

本文利用电子探针对新疆拜城碱性花岗岩中的烧绿石进行了研究.通过背散射图像分析可知拜城碱性花岗岩中烧绿石多为不规则粒状,颗粒直径在30 ～ 150 μm,与氟碳铈镧矿、萤石、磁铁矿等伴生;利用元素面扫描得出碱性花岗岩烧绿石中Nb、Ta、U、La、Ce、F等稀有、稀土元素的分布情况;并对碱性花岗岩中烧绿石进行了定量分析,表...     

A scanning electron microscope study of the cathodoluminescence in GaP led material

Cathodoluminescence in GaP doped with zinc and oxygen has been studied using a scanning electron microscope. In p-n structures grown by liquid epitaxy, a region of low luminescent efficiency is found near to the junction. This is explained by a higher concentration of non-radiative centres, due to either growth defects or impurities. Lamps made by double liquid epitaxy on pulled substrates increase in efficiency when annealed. No such increase occurs for layers grown by single or double liquid epitaxy on vapour grown substrates. The increase is correlated with the movement of the edge of the cathodoluminescent region towards the junction in the first case only.     

Scanning electron microscopy and cathodoluminescence study of the epitaxial lateral overgrowth (ELO) process for gallium nitride

Traditional epitaxial growth of GaN by metalorganic vapor phase epitaxy (MOVPE) on mismatched substrates such as sapphire or SiC produces a columnar material consisting of many hexagonal grains ∼0.2–1.0 μm in diameter. The epitaxial-lateral-overgrowth (ELO) process for GaN creates a new material: single-crystal GaN. We have studied the ELO process for GaN grown by MOVPE in a vertical flow rotating substrate reactor. Characterization consisted of plan-view SEM and vertical-cross-section TEM studies, which revealed a large reduction in dislocation density in the overgrown regions of the GaN. Panchromatic and monochromatic cathodoluminescence images and spectra were used to study the spatial variation of the optical properties within the GaN ELO samples. The effects of growth temperature and stripe material on the overgrown layers were examined. Through the use of a higher substrate temperature during growth and the use of a SiN_x stripe material, the overgrown crystal shape has a smooth 2D top surface with vertical sidewalls. Applying a second ELO step, rotated by 60°, over a fully coalesced ELO layer yields a further reduction of defects in GaN overgrown surfaces.     

Microwave Inversion of Leaf Area and Inclination Angle Distributions from Backscattered Data

The backscattering coefficient from a slab of thin randomly oriented dielectric discs over a flat lossy ground is used to reconstruct the inclination angle and area distributions of the discs. The discs are employed to model a leafy agricultural crop, such as soybeans, in the L-band microwave region of the spectrum. The distorted Born approximation, along with a thin disc approximation, is used to obtain a relationship between the horizontal-like polarized backscattering coefficient and the joint probability density of disc inclination angle and disc radius. Assuming large skin depth reduces the relationship to a linear Fredholm integral equation of the first kind. Due to the ill-posed nature of this equation, a Phillips-Twomey regularization method with a second difference smoothing condition is used to find the inversion. Results are obtained in the presence of 1 and 10 percent noise for both leaf inclination angle and leaf radius densities.     

大别山超高压变质矿物中的微结构缺陷及其意义

近年来，人们在大别造山带的变质岩中发现了许多用来指示超高压变质条件的标志性矿物和其他一些异常的矿物学现象，这些新的发现深化了人们对大陆板块俯冲和折返过程中的不同层次板片在构造动力学和地球动力学作用下演化的认识。本项工作用高分辨透射电镜（HRTEM）研究了大别山超高压变质岩中石榴石、绿辉石和硬玉的超微构造及变形结构特征，从超微观尺度揭示了不同变质地质事件产生的微观地质异常信息。     

高性能阴极荧光分析系统及其在氮化物半导体材料中的应用

本文介绍了一套高性能的阴极荧光（Cathodolumineseence简称CL）分析系统，该系统由一台场发射扫描电镜（FEI公司的Quatan 200F）和高性能阴极荧光谱仪（Catan公司的Mono Cl3＋和液氮冷台）组成。由于使用了场发射环境扫描电镜，不仅能获得高空间分辨的形象像，而且对观察试样无需进行任何预处理（包括绝缘样品甚至含水样品），这无疑为真实的显微分析提供了强有力的手段。     

跨界思索，从甲型H1N1流感看木马检测防范

自2003年SARS以来，类似这种具备广泛传染性的病毒事件屡见不鲜，从禽流感再到现在的甲型H1N1，可谓“一波未平，一波又起”。     

Fermi's golden rule, nonequilibrium electron capture from the wetting layer, and the modulation response in P-doped quantum-dot lasers

Electron capture from a quantum dot's (QDs) wetting layer is described by Fermi's golden rule that relates the transition rate to the density of final states. The wetting layer capture causes a brief nonequilibrium electron distribution between the QD ground state and its wetting layer states and can slow a QD laser's modulation response. This effect is studied for time constants and capture conditions relevant to self-organized InAs QDs. It is shown that even a moderately fast electron capture consistent with present low temperature measurements can limit a QD laser's modulation speed.     

Specific features of the cathodoluminescence spectra of AlInGaN QWs,caused by the influence of phase separation and internal electric fields

The specific features of the cathodoluminescence (CL) spectra in AlInGaN heterostructures, caused by the influence of phase separation and internal electric fields, observed at varied CL excitation density, are studied. It is shown that the evolution of the CL spectrum and the variation in the spectral position of emission lines of nanoscale layers with current density in the primary electron beam makes it possible to identify the occurrence of phase separation in the layer and, in the absence of this separation, to estimate the electric-field strength in the active region of the structure.