国标GB 3102.7-93《声学的量和单位》修订简介

国家技术监督局、国家教育委员会、广播电影电视部、国家新闻出版署于1994年11月14日联合发出的《关于在全国开展“量和单位”系列国家标准宣传贯彻工作的通知》中指出，重新修订的GB3100～3102－93《国际单位制及其应用》等15项有关“量和单位”的强制性系列国家标准，是涉及自然科学各个领域、各行各业必须执行的基础标准，也是国家法定计量单位的具体应用形式．为切实贯彻这套标准要求，所有1995年7月1日以后出版的科技书刊、报纸、新闻稿件、教材、产品铭牌和说明书等，在使用量和单位的名称、符号、书写规则时都应符合新标准的规定．…     

Ge_xSi_(1-x)/Si超晶格中周期不均匀对折叠声学声子拉曼线宽的影响

本文报导了在 Ge_Si_(1-x)/Si 超晶格中观察到了超晶格周期不均匀导致的折叠声学声子拉曼谱线展宽,这种谱线展宽与折叠指数(m)有关,折叠声学声子的谱线越宽,m 相同的折叠声学声子具有相同的线宽。     

2003年津鲁苏浙声学学术会议(21世纪声学技术创新论坛)在金华召开

十月金华,金桂飘香。正值浙江省“首届中国浙江学术节”隆重举办和浙江省声学学会成立十周年之际,2003年的10月11日,我们天津市、山东省、江苏省、浙江省三省一市声学学会联合举办的2003’津鲁苏浙声学学术会议(21世纪声学技术创新论坛)在浙江金华市隆重召开。天津市声学学会李允武理事长、王以真副理事长、山东省声学学会徐海亭理事长、江苏省声学学会陈伟中理事长、浙江省声学学会刘孟庵名誉理事长、崔晓文理事长、王兴荣、潘仲麟、张志涛、周利生、方健文、张三明副理事长以及各地的78名声学专家、学者、企业家和工作者出席了会议。会议特邀佳宾张淑仪院士出席了学术会议, 《应用声学》编辑部王丽生副主编到会。 刘孟庵教授主持了大会开幕式。浙江省声学学会     

On study of the theory and algorithm of the three dimensional coupled mode － parabolic equation

A fast algorithm of sound propagation in three dimensional underwater environments is presented. On the basis of the generalized phase integral (WKBZ) theory and the beam displacement ray mode (BDRM) theory, the coupled mode parabolic equation (CMPE) theory of sound propagation in range dependent underwater environment is extended for three dimensional (3D) problems. The CMPE3D solution is expressed in terms of the normal modes in vertical direction and the coupled mode amplitude coefficients in horizontal directions. By using the WKBZ theory and the BDRM theory, the local normal mode analysis can be processed efficiently. A PE-based algorithm, which was implemented in model FOR3D by Lee D et al [“Numerical Ocean Acoustic Propagation in Three Dimensions“, World Scientific, Singapore, 1995] is also adopted to solve the coupled mode amplitude coefficients. Numerical simulations indicate that the efficiency has been greatly improved by using CMPE3D instead of the PE approximations.     

Experimental studies on the multistage constant modulus array for the estimation of directions-of-arrival

The performance of the multistage Constant Modulus (CM) array, one of the most striking blind beamforming algorithms, for the source Directions-of-Arrival (DOA) estimation was analyzed via computer simulations and water tank experiments, and was compared to that of other DOA estimation algorithms including the ‘non-blind‘ and the ‘blind‘. Firstly, a nominal array model and an array model with gain and phase perturbations were established,respectively. Secondly, the multistage CM array algorithm was described and computer simulations were conducted. Simulation results showed that the multistage CM array could correctly estimate the DOA at the same time when the sources were blindly recovered, and the angle separating ability of the algorithm was beyond the Rayleigh resolution limit. By changing the variance of the array model errors, it was also verified that the multistage CM array was more robust to the errors than some other algorithms mentioned in this paper. Finally, water tank experiments and data processing results were provided. Situations with different array sizes and source angular separations were considered. It was shown that the results were in good agreement with computer simulations. Results of computer simulations and water tank experiments verified that the DOAs of the multiple independent sources could be blindly and robustly estimated with the multistage CM array.     

声学反问题的整体唯一性

It is proved that a sound-soft scatterer in R^N （N = 2, 3） is uniquely determined by a finite number of acoustic far-field measurements. The admissible scatterer possibly consists of finitely many solid obstacles and subsets of （N - 1）- dimensional hyperplanes.     

《应用声学》征稿简则

《应用声学》是声学领域的学术刊物，中国自然科学核心期刊，中国科学引文数据库、中国科技论文统计用刊，国内外公开发行，办刊的宗旨是繁荣应用声学事业，促进新成果的开发与推广，促进科研、工程技术人员与生产实践者之间的相互了解和合作，读者对象是从事声学方面科研、教学、医疗、产品与设备开发、科技管理、企业管理的工作者，以及大专院校学生。     

重视学生学习物理过程中的几个问题

物理学是一门研究物质运动规律．物质的基本结构及物质问相互作用的学科．它是其它自然科学和社会科学的基础．物理学揭示的时空与物质的关系及其相对性等概念深刻地影响着人们的哲学观念．物理学也是应用学科的基础．如电工学、无线电理论、微波理论都是以电磁场理论为基础；建筑学、水利学则要用到力学、声学等理论．根据物理学所涉及的内容和架构，以及物理学与先进的科学技术的关系，     

Stochastic Resonance in an Over-Damped Bias Linear System with Dichotomous Noise

The stochastic resonance in an over-damped bias linear system subject to multiplicative and additive dichotomous noise （DN） is investigated. By using the linear-response theory and the properties of the DN, the exact expressions are found for the signal-to-noise ratio （SNR）. It is shown that the SNR is a non-monotonic function of the correlation time of the additive DN, and it varies non-monotonically with the bias of the external field, the intensity and asymmetry of the multiplicative DN, as well as the external field frequency. Moreover, the SNR depends on the bias of the system, as well as the strength and asymmetry of the additive DN.     

863合成孔径声纳项目通过验收

由中国科学院声学研究所主持研制的国内第一套合成孔径声纳海试样机于2005年底在浙江舟山海域进行的海上试验中获得圆满成功，并于2006年初顺利通过863专家组验收。该样机不仅填补了国内空白，而且主要指标已经达到国际先进水平。