铝棒发音的实验研究

对科学探究实验室中的铝棒发音实验进行了多组对比实验,借助多媒体音频软件Cool Edit 2000,探究了铝棒发音的规律,得到了铝棒发音的初步实验结论.     

基于发音特征的汉语普通话语音声学建模

将表征汉语普通话语音特点的发音特征引入汉语普通话语音识别的声学建模中,根据普通话发音特点,确定了用于区别普通话元音、辅音以及声调信息的9种发音特征,并以此为目标值训练神经网络得到语音信号属于各类发音特征的后验概率,将此概率作为语音识别的输入特征建立声学模型。在汉语普通话非特定人大词表自然口语对话识别系统中进行了实验验证,并与基于频谱特征的声学模型进行了比较,在相同解码速度下,由此方法建立的声学模型汉字错误率相对下降6.8%;将发音特征和频谱特征进行了融合实验,融合以后的识别系统相对基于频谱特征系统的汉字错误率相对下降10.1%。上述结果表明,基于发音特征的声学模型更加有效的实现了对语音特性的表征,通过利用发音特征和频谱特征的互补性,能够进一步实现对语音识别性能的提高。     

汉语语调降阶的实验研究

采用设计特定声调组合的实验室语句的方法,研究了汉语普通话语调降阶的规律。结果发现,在普通话语调中,同样存在自动降阶和非自动降阶两种音高现象。在有低音介入的非自动降阶中,低音对后音节音域的影响表现在使音域上限降低,音域的下限保持不变;因此汉语中的降阶是语调高音特征的表现;低音特征声调会使低音后的高音发生正向降低和低音前高音的逆向提高,并且这两种作用是可以相互包容的。在自动降阶中,高音线的下降趋势是线性的,它受重音位置及重读程度的影响,在发音人中有较大差异。与已有的其他语言降阶研究的结果相比,汉语的降阶率不是固定的,且降阶的作用范围并不只局限于同低音相邻的音节。     

汉语普通话调制函数的实验研究

通过测量传输通路的调制转移函数而导出语言传输指数可以客观评价厅堂或扩声系统的语言清晰度。本文介绍了测得的汉语普通话的调制转移函数,比较了语言传输指数和快速语言传输指数的相关性并绘出汉语普通话音节清晰度和语言传输指数的关系曲线。     

汉语语调音高下倾的实验研究

通过提取和分析特定声调组合的实验室语句的音高曲线,探讨了确定条件下的汉语语句音高下倾趋势。分析结果表明,在不同类型声调组合的陈述句中,低音线清晰地呈现出以韵律短语为基本单元的下倾现象,下倾的斜率与韵律短语长度成反比.声调组合不同,以及承载下倾特征点的音节在韵律词中的位置不同,都会导致低音线下倾的斜率不同。具体表现为:(1)当低音点处于韵律词词首时,低音线斜率的绝对值大于低音点处于韵律词词末时的绝对值;(2)韵律短语音高下倾程度还受其在句中所处位置的影响,句首韵律短语的下倾程度大于旬末韵律短语的下倾程度;(3)主句包含多个韵律短语时,它们的低音线起点可以是依次单调递降的,具体的下倾模式受短语之间句法语义关系的制约。     

基于共振峰模式的汉语普通话中韵母发音水平客观测试方法的研究

提出了一种以元音的共振峰模式为特征基于支持向量机算法的分类评估方法,用以对汉语普通话中的韵母发音水平进行客观测试。此算法为每个韵母分别训练全分类模型、子分类模型和评估模型,在两级分类的基础上对发音水平进行测试打分。实验结果表明,全分类模型可以达到90%以上的分类正确率,客观测试与专家主观评估的相似度达到82%,在性能上超过了传统的以倒谱系数为特征的隐含马尔科夫模型方法。     

关于汉语音节知觉空间的实验研究

通过心理物理实验方法建构汉语音节知觉的多维空间结构,寻求有关汉语音节知觉的客观表现。结果表明,在声学特征层面上,音高和时长是音节知觉结构的主要维度;在韵律层面上,句中位置、韵律词长度等指标比较直观地反映了音节在知觉多维空间中的分布。     

汉语单音语音的频谱分析实验

介绍了一个用频谱分析的方法对汉语单音语音进行分析的实验。通过对不同发声人对同一汉字的发音进行频谱分析 ,得出其相应的频谱特性或变化规律。     

对变质量问题的实验研究

对变质量问题的实验研究王晓耕，郝利（承德石油高等专科学校，０６７０００）在大学物理教学和习题中常遇到变质量问题，我们在气垫导轨的滑块上增加了载沙槽装置，在导轨上端悬挂一沙漏斗，当载沙槽、滑块组成的系统在外力作用下沿导轨运动时，漏斗中的沙子匀速地落在运...     

汉语数字助听器高频听损增强方法的实验研究

提出采用正弦模型改善患者高频听觉的非线性降频方法。正弦模型语音分解得到的幅度、频率和相位是算法三个主要的处理参数。为了避免谱失真,将语音频谱按倍频程划分为6个部分。最接近并低于患者门限频率的部分,只做幅度放大处理。按照不同频段对于语音理解度的贡献程度,将患者门限频率以上的频率段压缩并转移到患者的可听频段,并将对应相位信息变为最接近的对应低频相位。在本研究中,10个受试者进行了语音理解度测试。测试结果显示,经过训练后,患者的平均理解率至少提高45%。下一步的研究应增加受试者数量,并增加对患者的听损情况的详细分析,从而设计出更合理,更细致的降频助听算法。     

微型蒸气压缩制冷系统实验研究

该制冷系统由微型回转式压缩机、管带式换热器和毛细管等组成,制冷剂为R134a。单机重2.21kg,体积210mm×140mm×160mm。2.0kg锂电池确保系统150min内持续提供73.6W冷量。利用空气焓差台测量压缩机转速、蒸发器进风温度和送风量等参数对于系统性能的影响。实验结果确定了影响性能的主要因素,且表明主动调节可使系统满足不同的制冷量和冷却温度要求。     

Experimental investigation of cavitational bubble dynamics under multi-frequency system

Acoustic emission spectra measurements have been carried out under mono and multi-frequency acoustic sources to understand the fundamental difference in bubble/cavity dynamics. The effect of introducing the dual and triple frequency acoustic waves of different frequency on the sono-chemical yield has also been investigated experimentally. The introduction of a second wave has increased the number of cavitating bubbles and as well as the collapsing intensity of cavities resulting into higher sono-chemical yield, and better effective utilization of reactor volume with a large number of resonating cavitating bubbles. To get the information about the intensity of each of the cavity oscillating events, decomposition of the pressure signal measured by the hydrophone in the frequency domain of the FFT power spectrum has been carried out. Inverse fourier reconstruction technique, has been used to elaborate the dynamics of the cavitating bubbles in the multi-frequency system.     

一种基于音素模型感知度的发音质量评价方法

为了提高发音质量判别精度,提出了一种基于音素模型感知度的发音质量评价方法。它采用不同语音样本集合下样本声学特征的对数后验概率期望差作为音素模型对变异发音的感知度,并以此为基础,生成各音素对应的识别模型候选集。实验表明,所提出的方法使语音识别网络候选音素模型集合尺寸减少约95%;在非母语语音数据库上,该方法评分与人工专家打分相关性为0.828,基于该方法得到的声韵母错误检出率为70.8%,声调错误检出率为42.5%,均优于其它方法。     

以HFC134a为制冷剂的喷射制冷实验研究

设计并搭建了喷射制冷系统性能研究实验台,选取HFC134 a作为制冷剂进行了喷射制冷实验研究。研究表明,在测试工况范围内,喷射系统的COP随蒸发温度的升高而增加,随冷凝温度的升高呈现先是基本不变,后迅速降低的趋势,随发生温度的升高先升高后降低;另外,研究还发现系统的COP随着冷冻水流量的增加而增加。     

Experimental assessment of a multicarrier underwater acoustic communication system

This paper presents a multicarrier communication system which transmits information on independent subcarriers to achieve an increased data rate. For this system, a passive-phase conjugation (PPC) based receiver structure is assessed by processing data collected in sea trials. Based on temporal diversity (pulse compression) exploited by PPC processing, an adaptive multichannel decision feedback equalizer is used to remove intersymbol interference, where spatial diversity is exploited by adaptive multichannel combination. The digital phase-locked loop (DPLL) technique is implemented for carrier-phase tracking. In the scenario of low input signal-to-noise ratios (SNRs), the receiver structure achieved superior performance using a common DPLL. In a depth-fluctuated environment, two sea experiments were conducted over ranges of 2 km and 4 km, respectively, and this communication system was assessed with a data rate of 4 kbps. In terms of mean square error, output SNR and bit error rate, this receiver structure has demonstrated its performance for the multicarrier communication system.     

Experimental investigation of slow light propagation in degenerate two-level system

Slowing a light pulse in a degenerate two-level system is observed with a double-frequency sweeping technique. The effects of coupling beam intensity, cell temperature and frequency detunings of the coupling and probe beams in resonance, on the slowing of light propagation in such a system are investigated. It is found that group velocities depend strongly on polarization combinations. A group velocity $v_{\rm g}$=6760m/s of light pulses in caesium vapour is obtained under the optimal parameters.     

Experimental investigation of preset electrostatic fields in a quasi-electrode system

We describe the results of implementation and breadboard investigations of the method for obtaining constant electric fields of a preset form in a quasi-electrode system. We have constructed a prototype (12 cm in diameter and 30 cm in length) with 36 filamentary electrodes fed with potentials from divider systems with azimuthal distribution laws corresponding to cosθ′, cos2θ′, and cos3θ′ laws with the maximal voltages up to ±2.4 kV. As a result, the electric dipole, quadrupole, and sextupole fields are formed. These fields are analyzed for a 2D cross section of the prototype by physical simulation on a specially developed device with conducting paper. The distributions of the families of equipotential curves measured using the bridge circuit are considered and the strengths of the three types of electric fields are calculated. The results indicate the attainment of all predicted fields with preset parameters and a working area of the aperture of ≥84%. Some other favorable features are also outlined and a number of technical recommendations for producing such fields are given.     

Experimental investigation of the quality of lensless super-resolution ghost imaging via sparsity constraints

Ghost imaging via sparsity constraints (GISC) can nonlocally realize super-resolution imaging. Factors influencing the quality of lensless super-resolution GISC are investigated and the experimental results show that, the quality of GISC is enhanced as the object?s sparse ratio in the representation basis or the spatial transverse coherence lengths on the object plane are decreased. The differences between ghost imaging (GI) and GISC are also discussed.     

Experimental assessment of a 3-D plenoptic endoscopic imaging system

An endoscopic imaging system using a plenoptic technique to reconstruct 3-D information is demonstrated and analyzed in this Letter. The proposed setup integrates a clinical surgical endoscope with a plenoptic camera to achieve a depth accuracy error of about 1 mm and a precision error of about 2 mm, within a 25 mm × 25 mm field of view, operating at 11 frames per second.     

Experimental investigation of the temperature field in the gas-liquid two-layer system

Results of an experimental investigation of the temperature field across the liquid-gas two-layer system are presented. The liquid layer is locally heated from the bottom substrate, and the intensive liquid evaporation is observed. A technique for measuring the temperature profile across the liquid and gas layers (including their interface) is developed. To do these measurements, the microthermocouple is moved across the layers with the help of precision micropositioner with a step of 1 μm. The temperature jump at the liquid-gas interface is measured, and its value increases with the temperature increase. Detailed information on the temperature field near the interface is obtained by using the precise thermocouple displacement with a small step.