The effect of task on determination of maximum phonational frequency range

The purpose of this study was to investigate if there was an effect of task on determination of maximum phonational frequency range (MPFR). Two tasks commonly used to elicit MPFR in clinical voice evaluations were compared. Normal adult females (N = 30) were examined. No statistically significant effect of task was found. Both tasks (glissando and discrete-step) were found to have a high positive correlation (0.84). Implications of the use of one task for determination of maximum phonational frequency range are discussed, as is the possibility of a task effect on determination of other voice parameters.     

ESR spectrometer with a wide frequency range using a gyrotron as a radiation power source

The development of a high frequency electron spin resonance (ESR) spectrometer with a wide frequency range using a gyrotron as the radiation power source is described.GYROTRON FU-E, optimized for use in an ESR spectrometer in the millimeter wave range, was developed in Fukui University. In order to test the normal operation of the spectrometer, the ESR of two standard samples, single crystal and polycrystalline DPPH, has been measured, in the pulsed mode over the frequency range from 65 GHz to 135 GHz.     

基于灰度和空间联合信息最小化的磁共振图像偏差场纠正

在磁共振图像（MR）的偏差场纠正中,针对灰度信息最小化方法没有考虑空间信息问题,提出联合信息最小化方法,该方法把图像的灰度信息和空间信息结合起来.空间信息采用灰度导数信息.被偏差场破坏的图像灰度及其导数值的联合信息（联合熵）大于对应的没被偏差场破坏的图像联合熵.联合熵是通过计算灰度及其导数值的联合概率分布得到.仿真脑部MR数据和临床脑部MR数据的试验结果都表明,灰度及其二阶导数联合信息最小化方法纠正效果良好,大大减少了脑白质和脑灰质的灰度交叠.     

Inelastic electron tunneling spectroscopy: Intensity as a function of surface coverage

Inelastic election tunneling spectroscopy (IETS) is a sensitive technique for obtaining vibrational spectra of molecules adsorbed on an oxide surface and incorporated into a metal-oxide-metal tunnel junction. IETS energy data are used routinely. However, IETS intensities contain additional information which, for theoretical and experimental reasons, has not been used systematically. This paper examines the variation of IETS intensity with surface coverage of dopant molecules in the junction, a relationship of practical and theoretical importance. IET spectra are taken using standard experimental techniques and a liquid doping technique which allows the surface coverage to be determined independently. From an analysis of a large number of modes of benzoic acid on alumina, it is found that IETS intensity, defined in the usual way as the normalized change in conductance, $\text{Δ σ}\text{σ}$, is a nonlinear function of surface coverage. A physical model is presented which attributes this behavior to a difference in elastic tunneling conductances through empty or filled regions of the dopant layer in a junction with a fraction of a monolayer coverage. In addition, the liquid and vapor doping techniques in common use in IETS are discussed in terms of statistical mechanics and are shown to be manifestations of the same basic phenomenon.     

Intensity discrimination as a function of level and frequency and its relation to high-frequency hearing

This paper examines how intensity discrimination depends on the test frequency, the level, and the subjects's high-frequency hearing. Three experiments were performed. In the first experiment, intensity discrimination of pulsed tones was measured as a function of level at 1 and 14 kHz in five listeners. Results show less deviation from Weber's law at 14 kHz than at 1 kHz. In the second experiment, intensity discrimination was measured for a 1-kHz tone at 90-dB SPL as a function of the cutoff frequency of a high-pass masking noise in two listeners. Results show that the audibility of very high frequencies is important for frequency discrimination at 1 kHz. The DL increased by a factor between 1.5 and 2.0 as the cutoff frequency of the noise was lowered from 19 to 6 kHz. In the third experiment, thresholds from 6 to 20 kHz and intensity discrimination for a 1-kHz tone was measured in 12 listeners. Results show that the DLs at 80-dB SPL are correlated with the ability to hear very high frequencies. Results of all three experiments are consistent with the multiband version of the excitation-pattern model for intensity discrimination [Florentine and Buus, J. Acoust. Soc. Am. 70, 1646-1654 (1981)].     

背景扣除和强度校正对激光诱导等离子体光谱参数的影响

激光诱导击穿光谱技术以其无需样品预处理、分析速度快、能实现多元素同时检测和远程分析等优点已经被广泛应用于诸多领域的物质成分定性或定量分析。该技术的理论基础是激光诱导等离子体。对等离子体光谱参数(如光谱谱线强度、等离子体温度等)的准确测量是利用该技术进行定性或定量分析的前提条件。实际的实验系统中,由于仪器本身固有的性能限制,会造成采集光谱信号的失真,从而限制等离子体光谱参数的精确测量或计算。为了克服仪器固有性能的影响,分析了实验系统所用中阶梯光栅光谱仪和传输光纤的固有性能缺点对光谱信号背景噪声和元素谱线绝对强度的影响,然后采用剥峰法对光谱信号中存在的锯齿状背景噪声进行扣除,利用辐射定标光源的标准光谱数据对谱线绝对强度进行校正,并对比了背景扣除和强度校正对等离子体谱线强度和等离子体温度的影响,实验表明谱线强度校正对合金钢等离子体380 nm以下的光谱信号具有较大影响,通过背景扣除和强度校正后,等离子体温度由13 401.75 K降低至8 980.72 K,玻尔兹曼平面法求解等离子体温度的拟合决定系数由0.60提高至0.91。因此在光谱数据处理之前对测量光谱进行背景扣除和强度校正是十分必要的,为提供可靠地光谱数据进行物质成分定性或定量分析奠定了基础。     

会聚厄米-双曲余弦高斯光束的光强分布和焦移

 基于厄米-双曲余弦高斯光束通过无光阑限制薄透镜聚焦的解析传输公式，研究了厄米-双曲余弦高斯光束聚焦区域的光强分布，并对光束的焦移进行了分析，讨论了偏心参数对光强主极大位置的影响。结果表明：TEM₁₁模厄米-双曲余弦高斯光束的相对焦移（绝对值）随偏心参数和菲涅尔数的减小而增大，菲涅尔数较大时相对焦移趋于零。TEM₂₂模光束在偏心参数小于0.54时，轴外与轴上光强极大值的比值大于1，此时光强主极大在轴外，偏心参数大于0.54时则相反；在偏心参数等于0.54时比值为1，此时光束有两个主极大，偏心参数愈大光强愈集中于轴上。使用LW法和GH法得到的TEM₂₂模光束的相对焦移（绝对值）随偏心参数和菲涅尔数的变化规律与TEM₁₁模光束一致，但相同参数下使用这两种方法得出的具体结果不同。     

强度调制型光纤折射率传感器的设计与研究

研制了一种基于菲涅耳反射原理的测量液体折射率的光纤传感器.该传感器采用普通FC/PC尾纤插头作为传感头.整个实验系统需要的元件少、光路简单.讨论了测量的基本原理和数据处理方法.采用相对强度的数据处理方法,有效地消除了光源不稳定性和光路中各种损耗所带来的误差,提高了系统的测量准确度.实验结果表明,测量准确度能够达到10－4 量级,并且适合微量液体的测量.该测量方法还可扩展到固体、气体和其它与折射率相关参量的测量.     

环境气氛对高能量激光诱导等离子体辐射特性的影响

采用高能量钕玻璃激光器(～25 J)激发诱导金属等离子体,研究了环境气体及其压力对等离子体辐射特性的影响。实验结果表明,相同压强下,氩气中等离子体的谱线强度明显高于空气中等离子体的谱线强度;0.8×105Pa氩气条件下,光谱标钢等离子体的谱线强度达到了最大值;随着环境气压的增大,谱线自吸明显增强,当环境气压达到(0.8～0.93)×105Pa时,标样铝的AlⅠ308.22 nm和AlⅠ309.27 nm两条谱线产生了严重自蚀;另外,等离子体的激发温度也随环境气压的增大而增大,0.93×105Pa氩气条件下标钢等离子体的激发温度相对于0.43×105Pa时升高了近1 500 K。     

在依赖强度耦合Jaynes-Cummings模型中制备光场的相干态的叠加态

提出一个制备光场具有可控制的权重因子和相位和相干位态的叠加态的方案。它是基于在依赖强度耦合Ｊａｙｎｅｓ－Ｃｕｍｍｉｎｇｓ模型中对通过腔中的原子进行选择测量。     

Comparisons of intensity measures and their stability in male and female sneakers

The purpose of the present study was to provide data on the intensitycharacteristics of young adult speakers in terms of conversational intensity level, conversational intensity range, and available intensity range. Subjects included 20 males and 20 females, ages 20–30 years. Each subject was asked to read the Rainbow Passage at a conversational intensity level, as softly as possible without whispering, and as loudly as possible, on 2 separate days 1 week apart. The second and third sentences of the three readings on both days were analyzed for various intensity parameters. Results revealed a conversational intensity level of 70.42 dB for males and 68.15 dB for females. When male and female intensity measures were compared, few statistically significant differences were found. Further, when intensity measures for the first and second readings were compared, few significant differences were found.     

Normative thresholds in the 8- to 20-kHz range as a function of age

Using a prototype high-frequency audiometer, auditory thresholds in the 8- to 20-kHz range were obtained from 240 subjects ranging in age from 10-60 years. These measurements were obtained in interest of developing a normative database for frequencies above 8 kHz, and to evaluate intersubject variability as a function of age. An analysis of variance (ANOVA) revealed significant effects of frequency, age, and sex, and a significant frequency-by-age interaction. The largest changes in sensitivity with age occurred between 40 to 59 years. Below approximately 15 kHz, the intersubject variability of threshold estimates increased as a function of both age and frequency. Further analysis revealed that the age-related changes in variability were related to absolute thresholds rather than to age per se. When data are converted to dB HL (relative to the youngest group tested), the region of maximum hearing loss shifts to lower frequencies with increasing age, and threshold shifts with age are greatest in the 13- to 17-kHz range.     

A method to accurately measure and respond to an underwater sound pulse in a wide dynamic range

I.IntroductionTomeasurethesound1evelofanundcrwatersoundpulsewithunknownamplitudeisofimportanceinunderwaterapp1ication.Forinstancc,asimu1ationsystemusedtointerfcresomesonarmusthavesuchfunction,whichhastobeabIctomeasurethesoundlcvelatreceivingpointandretransmitasimulatcdsignalwithrequircdsoundlcvelafterpropcrprocessing.Itisdifficultforanorma1peakorthresho1ddetectortocompletethistask.Thereasonforthisisthattherangeofthesignalamp1itudercaches7O-8odBandthereissomedistortionofsignalwaveform,inaddit…     

Intensity normalization of additive and multiplicative spatially multiplexed patterns with n encoded phases

An efficient, robust and user-free intensity normalization method for patterns with n frequency-multiplexed phases of both additive and multiplicative types is proposed. For this, the parameter estimation approach by using the least-squares method is applied. The theoretical principles are given and the good performance of the proposal is verified by computer simulation and experimental results. Because the proposed method has good features such as robustness, simplicity, fast and user-free execution, it could be implemented in a wide variety of applications. This contribution motivates future generalization in both phase demodulation algorithms and experimental setups to exploit the benefits of additive/multiplicative patterns with multiple phases.     

Application of a micro-Brillouin scattering technique to characterize bone in the GHz range

The evaluation of elastic properties of bone matrix has been investigated using several techniques such as nanoindentation and scanning acoustic microscopy (SAM). These techniques make use of good spatial resolution, which can prevent effects due to microstructures at the level of several hundreds of microns. In this paper, micro-Brillouin scattering (μ-BR) is introduced as another possible technique to characterize the elastic properties of bone. This technique is well known as a non-contact and non-destructive method to evaluate viscoelastic properties of transparent materials in the GHz range. Using thin, translucent bone specimens with thicknesses of around 100 μm, and the reflection induced optical geometry, ultrasonic wave velocities in the GHz range were obtained. Because this technique optically measures thermal phonons in the specimen, we can easily measure in-plane anisotropy of wave velocities by rotating the specimen. In a single trabecula, the site matched data between SAM and μ-BR showed good correlation, revealing the applicability of this technique to characterize material properties of bone. Some recent results on the anisotropy in a trabecula and the elasticity evaluation of newly and matured bones are also introduced.     

基于无芯光纤强度调制型液位传感器的设计与性能

利用强度调制型光纤传感器容易解调的优势,提出了一种强度调制型光纤液位传感器.传感器由三根无芯光纤组成,其中,无芯光纤1与无芯光纤2串联构成测量臂,无芯光纤3构成参考臂.仿真分析得出,无芯光纤长度每缩短1mm,透射峰波长增加25.46nm.在0~50mm小液位范围内,实验测得传感器在水、5%NaCl、10%NaCl和15%NaCl水溶液四种液体环境中的液位灵敏度分别为0.069 5dB/mm、0.074 73dB/mm、0.077 49dB/mm及0.082 71dB/mm,线性度分别为0.998 25、0.998 49、0.988 11及0.995 13,线性度较高.该传感器可较好地消除光源光功率波动与环境温度变化带来的影响,重复性较好,在石油化工领域有一定的应用潜力.     

楔形海域中三维效应对声源距离估计的影响分析*

楔形海域中声传播会出现显著的三维效应,导致水平方向上特定接收位置的声信号出现模态多次到达或者模态影区。利用射线模型,首先对楔形波导中的传播损失进行计算,分析三维效应的存在对于声波传播的影响, 结果表明,随着距离的增加,水平折射效应愈加明显,所得的三维结果与利用二维模型计算所得相差逐渐增大。然后对比二维声场和三维声场中的接收波形,并对其进行模态分离,证明在某些接收位置将会出现明显的模态多次到达或模态影区。最后通过匹配全波解以及分离出的各号简正波所对应的脉冲波形进行声源距离估计研究,并分析三维效应对于声源距离估计结果的影响。结果表明,由于三维效应的存在,使用三维模型能够得到准确估计声源距离,而利用二维模型进行估计得到的结果与实际距离相差较多,总体上偏大。     

加性信号调制下指数形式关联噪声驱动的单模激光的光强关联时间

采用线性化近似,计算了加性信号调制下的由具有指数关联的两白噪声驱动的单模激光增益模型的光强关联时间.发现两噪声间关联程度对光强关联时间随噪声强度的变化曲线有很大的影响,两噪声间关联程度取不同值时,光强关联时间随噪声强度的变化曲线中将出现极大值(即出现共振) 或极小值(即出现抑制) .