基于Teager能量算子（TEO）基频的应力影响下的变异语音分类

变异语音识别是一项极具挑战意义的研究课题,一种解决方法是在前端对语音进行变异分类,然后根据不同变异情况采用相关的处理算法。在各种语音变异中,说话人在战斗机、航天飞机座舱等环境中,身体受到应力(重力)影响时的情况更具有特殊性。其所引起的发音变异有别于因心理的、感知的或生理的因素所引起的变异,目前国内外还鲜见有关应力影响不变异语音分类问题的专门研究。木文从对应力影响下的几种基于基频的语音特征的分析出发,提出了对应力影响下的变异语音和正常语音进行分类的方法。对航空模拟飞行器中采集的小词表实验样本,特定人平均分类正确率达到了93.3%,多说话人分类上确率达到了85.8%。     

Synthesis and luminescence of a novel conjugated europium complex with 6-parachloroaniline carbonyl 2-pyridine carboxylic acid

A novel organic ligand, 6-parachloroaniline carbonyl 2-pyridine carboxylic acid, and the corresponding europium complex, tris(6-parachloroaniline carbonyl-2-pyridine carboxylate) europium (III) have been designed and synthesized. The results showed that the synthesized product was a conjugated complex, emitting remarkable strong red luminescence, and was a good red luminescence material with good thermal stability. The ⁵D₀ lifetime of Eu³⁺ in the complex was examined using time-resolved spectroscopic analysis. The lifetime values for 1.0×10⁻⁵ mol/l ethanol solution of the complex and for the complex solid were 0.49±0.01 and 1.94±0.01 ms, respectively.     

基于虚拟仪器的人体皮肤组织吸收光谱检测平台

本文运用光电无损检测技术,采用皮外反射式测量方法,通过光纤光谱仪和虚拟仪器构建人体皮肤组织吸收光谱检测平台.该平台适合于光子-组织相互作用基础研究及激光美容临床检测,可协助医师进行病理诊断和病变程度判别.文中给出几个吸收光谱的检测结果.     

Laser–MBE growth of high-quality ZnO thin films on Al2O3(0001) and SiO2/Si(100) using the third harmonics of a Nd:YAG laser

High-quality ZnO thin films were grown on single-crystalline Al₂O₃(0001) and amorphous SiO₂/Si(100) substrates at 400–640 °C using laser molecular beam epitaxy. For film growth, the third harmonics of a pulsed Nd:YAG laser were illuminated on a ZnO target. The ZnO films were epitaxially grown on Al₂O₃(0001) with the narrow X-ray diffraction full width at half maximum (FWHM) of 0.04° and the films on SiO₂/Si(100) exhibited a preferred c-axis orientation. Furthermore, the films exhibited excellent optical properties in photoluminescence (PL) measurements with very sharp excitonic and weak deep-level emission peaks. At 15 K, PL FWHM values of the films grown on Al₂O₃(0001) and SiO₂/Si(100) were 3 and 18 meV, respectively. Received: 8 May 2001 / Accepted: 18 September 2001 / Published online: 20 December 2001     

苯基取代聚乙炔中的元激发

苯环取代聚乙炔是一类具有简并基态的发光聚合物.利用扩展的SuSchriefferHeeger模型,研究了这类聚合物链中的孤子、极化子等元激发特性.结果表明:由于苯环与聚乙炔主链间的强π电子耦合,苯环取代抑制了聚乙炔主链的二聚化,减小了导带与价带之间的能隙;因此取代聚乙炔中的元激发具有较小的激发能,同时具有更大的相干长度.尽管苯基取代对元激发有很大的影响,但是非取代聚乙炔中元激发的基本物理规律依然成立,表明这些元激发的基本特性不受取代基团的影响 关键词： 孤子 极化子 苯基取代聚乙炔     

Semipolar (11\bar 2\bar 2) ZnO thin films grown on LaAlO3‐buffered LSAT (112) single crystals by pulsed laser deposition

Semipolar (11\bar 2 \bar 2) ZnO was successfully grown on (112) LaAlO₃/(LaAlO₃)_0.29(Sr₂AlTaO₆)_0.35 substrate by pulsed laser deposition. The epitaxial relationship is [11\bar 23]_{\rm ZnO} // [11\bar 1]_{\rm LAO/LSAT} with the polar axis of [000\bar 1]_{\rm ZnO} pointing to the surface. For ZnO films with thickness of 1.6 μm, the threading dislocation density is ～1 × 10⁹ cm^–2, and the density of basal stacking faults is below 1 × 10⁴ cm^–1. The (11\bar 2 \bar 2) ZnO exhibits strong D⁰X emissions with a FWHM of 9 meV and very few green–yellow emissions in the low‐temperature (10 K) and room‐temperature photoluminescence spectra, respectively.

     

超短时延测量DFB激光器的动态线宽

激光器调谐过程中的动态线宽是非常重要的参数, 然而, 当前各种测量方法得到的都是激光器稳定状态下的静态线宽. 本文提出一种对干涉拍信号进行基于局部均值分解的时频分析进而获取激光动态线宽的方法, 通过仿真信号验证了这种时频分析方法提取瞬时相位噪声的有效性; 构建实验系统, 利用10cm路径差产生约0.5ns的超短时延, 提取相位噪声的时频分布, 首次得到了分布反馈半导体激光器在脉冲工作模式下的动态线宽. 关键词： 超短时延 动态线宽 局部均值分解 时频分布     

基于1–10GHz空地链路信号的雨强监测方法可行性研究

空地链路上的微波信号受降雨影响, 会产生功率衰减和去极化效应. 基于这些物理特性, 本文提出利用1–10 GHz空地链路信号的降雨干扰项获取雨强的方法, 并开展了相关理论研究. 根据空地链路信号与雨滴复杂的相互作用, 研究了空地链路信号频率为1–10 GHz时, 雨强 (rain rate, R) 对衰减 (attenuation, A) 和交叉极化分辨率 (cross-polarization discrimination, XPD)的影响, 分别建立了A-R和XPD-R关系模型. 通过数值模拟, 分别分析了利用上述两个关系模型估测雨强的可行性, 并系统研究了不同频率、极化方式和仰角条件下的适用性. 研究结果表明, 对于水平极化或圆极化, 且频率较高的空地链路信号, 利用A-R关系反演强降雨具有理论上的可行性; 对于不同频率和极化方式的信号, XPD-R关系模型都可以用于反演雨强, 并且对于1–50 mm·h^-1范围内的雨强, XPD较为敏感; 不同仰角条件下, A-R和XPD-R 模型都适用. 在4–10 GHz时, 本文的XPD-R模型和国际电信联盟ITU-R中XPD预测模型的结果非常接近. 所得出的结论对于下一步开展相关的验证实验, 拓展卫星系统的气象应用, 实时估测降雨强度, 实现全球降雨观测具有重要的参考价值. 关键词： 空地链路信号 雨强 衰减特性 交叉极化分辨率(XPD)     

An analog of double electromagnetically induced transparency with extremely high group indexes

An asymmetric metamaterial exhibiting an analog of double electromagnetically induced transparency(EIT) in the middle-infrared region is reported.The metamaterial consists of two-layered arrays of Ushaped rings embedded in a medium,with the lower layer rotated by 90°.Our simulations demonstrate that both maximum group indexes are extremely high at the two EIT-like positions.The group index reaches about thrice the currently reported maximum value at the high-frequency EIT-like position.The transmittance at the two transparency positions also possesses extremely high Q factors,which is conducive to controlling the propagation of electromagnetic waves.     

Ranking spreaders by decomposing complex networks

Ranking the nodes? ability of spreading in networks is crucial for designing efficient strategies to hinder spreading in the case of diseases or accelerate spreading in the case of information dissemination. In the well-known k-shell method, nodes are ranked only according to the links between the remaining nodes (residual links) while the links connecting to the removed nodes (exhausted links) are entirely ignored. In this Letter, we propose a mixed degree decomposition (MDD) procedure in which both the residual degree and the exhausted degree are considered. By simulating the epidemic spreading process on real networks, we show that the MDD method can outperform the k-shell and degree methods in ranking spreaders.