频率恒定条件下不同响度声音听觉判断绩效研究

为实际声音的编码选择提供科学依据，对8名大学本科生被试，用耳机呈现声音，计算机控制进程，实验研究了恒定频率下6种不同响度的声音的绝对辨别能力和听觉判断绩效。得到了在固定频率为1000Hz条件下，6种不同响度声音的优先级：92．1dB、62．9dB、86．2dB、80．4dB、68．8dB、74．6dB。为不同声音编码提出了声音选择方案。     

响度恒定条件下不同频率声音听觉判断绩效研究

通过研究人对固定响度为60dB条件下的不同频率声音的绝对辨别能力的实验，探讨了6种不同频率声音的听觉判断绩效，结果表明：在固定响度为60dB条件下，6种频率的声音选择的优先级分别是：144Hz、5553Hz、299Hz、1289Hz、2675Hz、621Hz。为不同声音编码系统提出了选择方案。     

试论影响电影声音响度的四个要素（一）

本文论述了影响声音响度的四个要素,它们分别是：声音电平对声音响度的影响、声音频率对声音响度的影响、声音作用时间对声音响度的影响及声像及空间定位对声音响度的影响。下面分别予以论述。     

试论影响电影声音响度的四个要素（二）

二、声音频率对声音响度的影响用声音频率控制好声音的响度,需要先从频率自身性质这个基础谈起,根据频率与响度之间的关系,了解它们是如何彼此影响,相互作用的。声音频率（主要是基频）确定声音的音调———是声音高低的表征作用。他们之间的关系并非呈正比,而是成对数关系。什么影响人耳对声音频率的感受？     

豚鼠耳蜗基底膜响应特性的实验测试与分析

为探究耳蜗基底膜的动态特性,利用激光多普勒测振仪(Laser Doppler Vibrometer,LDV)测试了豚鼠耳蜗基底膜在纯音激励下的动态响应。实验时,选取了14只新鲜的豚鼠耳蜗离体标本,分别测试了70 dB、80 dB、90 dB三种声激励下耳蜗基底膜的速度响应和位移响应,并改变输入声音信号的频率,研究了基底膜的振动特性。实验结果表明:纯音激励下基底膜的振动是正弦振动;在大小相同、频率不同的纯音激励下,基底膜同一位置处振动速度和振动位移大小不同,基底膜具有频率选择特性,在最佳频率处振动响应最大;基底膜在不同大小声压激励下相位响应趋势接近,超过最佳频率后相位滞后迅速增加;基底膜的运动具有行波特征。实验方法和测试结果可为人耳耳蜗听觉机制的研究提供指导。     

豚鼠耳蜗基底膜响应特性的实验测试与分析EI北大核心CSCD

为探究耳蜗基底膜的动态特性,利用激光多普勒测振仪(Laser Doppler Vibrometer,LDV)测试了豚鼠耳蜗基底膜在纯音激励下的动态响应。实验时,选取了14只新鲜的豚鼠耳蜗离体标本,分别测试了70 dB、80 dB、90 dB三种声激励下耳蜗基底膜的速度响应和位移响应,并改变输入声音信号的频率,研究了基底膜的振动特性。实验结果表明:纯音激励下基底膜的振动是正弦振动;在大小相同、频率不同的纯音激励下,基底膜同一位置处振动速度和振动位移大小不同,基底膜具有频率选择特性,在最佳频率处振动响应最大;基底膜在不同大小声压激励下相位响应趋势接近,超过最佳频率后相位滞后迅速增加;基底膜的运动具有行波特征。实验方法和测试结果可为人耳耳蜗听觉机制的研究提供指导。     

声音的客观评价

如果要用仪器测量声音的响度级,必须模仿人的听觉幅频特性。根据响度级的定义可知,响度计应该由测量声音声压级的＂声（压）级计＂插入模仿人的听觉幅频特性的计权网络组成。一般选取三种计权特性来代表人的听觉幅频特性。如图1所示,国际电工委员会（IEC）规定A、B、C三条曲线代表人的听觉幅频特性的计权特性：A计权曲线是模仿声压级在（0～30）dB时人的听觉幅频特性;     

音响基本文档节目优化机DP600

专业音响节目优化机DP600是一种创新的、使用灵活的音响管理系统,能提供世界一流的智能化音响基本文档的声音响度分析和响度校正,与当今使用的诸多广播专业音响、视频点播VOD媒介文档格式兼容,也是一套工作流程管理工具,可以进行编码、解码和自动译码的选择,在支持的文档格式中可使操作效率更高。     

柴油机声品质客观参量测试及分析

在柴油机的不同速度和负荷下,进行现场噪声测试,并且分析了响度、尖锐度、粗糙度和抖动强度等4种噪声客观评价参量。经数据分析后可知,特征响度曲线能准确反映决定人耳听觉响亮程度感受变化的声音频率成分。随着发动机转速与负荷的增加,噪声的响度值和尖锐度值呈现了明显递增的趋势。同时,在900 r/min～1 700 r/min范围内,抖动度值也呈现了明显减小的趋势。     

基于H型超材料的小型化调频空间滤波器

基于超材料的相位补偿特性实现特定波段超材料滤波器设计。本工作通过变形传统的互补型开口谐振环,设计了一种小型化哑铃型缝隙结构超材料滤波器,通过二极管控制超材料的电磁特性在不同时间的空间分布形式,以实现空间滤波器中心频率可调。滤波器单元尺寸为5.0 mm×5.0 mm×0.8 mm,具有小型化的特点。仿真结果表明:-10 dB工作带宽为28%(9.2～12 GHz),回波损耗最小值为29 dB,插入损耗最大值为0.8 dB。测试结果表明:-10 dB工作带宽为25%(9.2～11.7 GHz),回波损耗最小值为20 dB,插入损耗最大值为1.0 dB。     

基于舱段数据的整船冲击环境组合预报方法

随着舰载设备抗冲击研究的不断发展,能否准确预报水下圆柱壳的整体冲击环境对于设备的布置与安装具有重大意义。对圆柱壳进行水下爆炸试验是一种具有较高可信度的研究手段,但成本巨大,相对而言,舱段试验较为容易方便。本文对比了舱段与整体水下圆柱壳的冲击环境差异,发现水下圆柱壳与舱段的冲击环境差异主要集中于低频段,水下圆柱壳的低频响应以低阶振动模态为主,而舱段的低频响应以刚体运动为主。根据上述差异,本文结合经验模态分解法、船体梁理论,提出了以舱段冲击环境数据来预报整个圆柱壳冲击环境的组合方法,且具有较高的模拟精度。     

Tuning the Doping Type and Level of Graphene with Different Gold Configurations

Au nanoparticles and films are deposited onto clean graphene surfaces to study the doping effect of different Au configurations. Micro‐Raman spectra show that both the doping type and level of graphene can be tuned by fine control of the Au deposition. The morphological structures of Au on graphene are imaged by transmission electron microscopy, which indicate a size‐dependent electrical characteristic: isolated Au nanoparticles produce n‐type doping of graphene, while continuous Au films produce p‐type doping. Accordingly, graphene field‐effect transistors are fabricated, with the in situ measurements suggesting the tunable conductivity type and level by contacting with different Au configurations. For interpreting the experimental observations, the first‐principles approach is used to simulate the interaction within graphene–Au systems. The results suggest that, different doping properties of Au–graphene systems are induced by the chemical interactions between graphene and the different Au configurations (isolated nanoparticle and continuous film).     

Vortex Pattern and Local Density of States in High-Temperature Superconductors with Different Hole-Doped Level

Vortex charges in high-temperature superconductors (HTS) with a different hole-doped level are investigated by Bogoliubov–de Gennes equations based on a model Hamiltonian with competing antiferromagnetic (AFM) and d-wave superconducting order (DSC). Our results show that the AFM order inside the vortex core becomes significant for the underdoped sample, which competes with the DSC order through expulsion of the holes from outside the vortex core and leads to a negative vortex charge, whereas the vortex charge shows a double-vortex center with a positively charged core and a negatively charged core for a slightly overdoped level; and the positive vortex charge may occur for a highly hole-doped level. Moreover, local density of states indicates that the presence of the AFM order in the vortex core provides a mechanism for splitting of the zero-bias conductance peak into local peaks at the core center.     

Effects of Stress Level and Stress State on Creep Ductility:Evaluation of Different Models

The last few decades have witnessed an increasing emphasis on the development of strain-based approach for predicting the creep life or damage of components operating at elevated temperatures. Creep ductility, as a key parameter in this approach, may vary with a number of factors including strain rate,state of stress, operating temperature, material microstructure, etc. The present paper, however, is focused on reviewing the state-of-the-art understanding of the effects of stress level and stress state on the creep ductility. Mechanisms involving the void growth and coalescence are presented to describe the role of stress level in the variation of uniaxial creep ductility. The prediction capacity of existing empirical ductility models is also assessed in light of uniaxial test data. On the other hand, a vast body of multiaxial creep test data, collected from open literature, is utilized to examine the influence of the state of stress on the creep ductility. Then, a variety of multiaxial ductility factor models are introduced and evaluated with the available experimental data. Finally, a brief discussion on the dependence of creep ductility on the stress triaxiality and Lode parameter, predicted by numerical methods, is provided.     

不同主导权结构下服务水平对高铁快递供应链价格策略的影响

基于“高铁网+快递网”的高铁快递模式出现,为研究主导权对高铁快递供应链价格策略的影响,分别建立集中决策、中铁快运主导、传统快递企业主导、Nash均衡的Stackelberg博弈模型,得到4种模式下中铁快运和传统快递企业的最优价格及最大利润。研究表明,不同主导权结构下的最优直销价格保持不变,最优零售价格则在主导权分散时最高;协议运价受主导企业的价格管控;主导权的分散将导致供应链整体利润受损;主导权有利于主导企业获得更大利润。     

Quantitative Analysis of Multiple Proteins of Different Invasive Tumor Cell Lines at the Same Single‐Cell Level

Tumor cell invasion is pivotal to the development, metastasis, and prognosis of tumors. It is reported that the invasive ability of tumor cells is mainly dependent on the expression levels of membrane type‐1 matrix metalloproteinase (MT1‐MMP) and integrin α_Vβ₃ proteins on cell membranes. To precisely distinguish between tumor cells with different invasive abilities, it is important to establish a highly sensitive and precise quantification method to differentiate the expression levels of MT1‐MMP and integrin α_Vβ₃ in the same single tumor cell at the same time. Herein, two functional peptides to construct red‐emissive Au₂₆ clusters and green‐emissive Ag₁₂ clusters are reported. Moreover, the Au₂₆ clusters and Ag₁₂ clusters have the ability to specifically target MT1‐MMP and integrin α_Vβ₃, respectively, in the same single cell at the same time. By utilizing the fluorescent properties and metallic compositions of metal clusters, the MT1‐MMP and integrin α_Vβ₃ levels of the more invasive SiHa cells or the less invasive HeLa cells are simultaneously and quantitatively differentiated via laser ablation inductively coupled plasma mass spectrometry. This method of quantitatively detecting multiple invasive proteins on the same cell is of great value for accurately diagnosing aggressive tumors and monitoring the invasiveness of these tumors.     

超低电平测试系统

＠冯彪＠陈德明￥中国卫星海上测控部１引言处理非常微弱信号的能力是无线电领域十分关心的问题,因为提高接收机灵敏度比增加发射机功率或天线增益更为经济。近年来,频率合成器的输出电平越来越低。ＨＰ８６６５Ｂ最低输出电平为－１４０ｄＢｍ,ＦＬＵＫＥ６０８０Ａ为－１４...