北极水声学：一门引人关注的新型学科

北极水声学是一门研究北极及其毗邻海域水声环境效应的学科。研究内容包括海洋环境噪声,特别是冰盖下的海洋环境噪声;北极海区的混响特性;北极及其毗邻海域的水声传播规律、冰盖下的水声通信,以及由于北极海区的独特环境(所谓半声道效应)而给水声信号处理带来的新的研究课题。北极水声学的研究开始于二次世界大战之后,当时的研究内容明显的带有冷战的烙印。近年来由于地球变暖的趋势,北极冰区面积持续减少,北极航道有望开通。又由于北极高纬度地区的丰富的自然资源,引起各海洋大国的高度关注,北极水声学已成为新的研究热点,并注入了新的内容。本文综述介绍北极水声学的研究概况,以及和北极声学密切相关的海洋声学方面的研究课题。自从上世纪90年代以来,我国科学家对探索北极表现了极大兴趣,本文简要介绍我国对北极的5次海洋考察和正在进行的第6次考察。对我国在北极及其毗邻海域水声学研究方面所面临的挑战提出初步的应对措施。     

松花江冰下声学试验技术研究

北极区域极具战略意义与商业价值,随着各国的广泛关注,针对北极地区开展的科考科研活动逐渐增多。其中北极海域的相关研究尤为重要,特别是北极水声学,是保障北极军事存在以及正常科考科研活动的重要支撑。课题组于2015年1月在哈尔滨松花江进行了冰下声学试验,主要内容包括冰下信道测试、冰层散射系数测量以及冰下水声通信试验,实现了冰下半波导现象的初步观测、冰层前向散射系数的测量、基于能量检测器的低信噪比扩频通信、基于时反镜判决反馈均衡技术的高速水声通信以及冰下12用户多址水声通信等内容。本文对本次冰下声学试验情况进行介绍,并给出了相应的试验结果及经验总结。     

北极跨冰层水中声源方位估计实验与分析

为了获取北极冰下声源方位信息,在北极冰层上方布放检波器和冰下投放声弹声源开展了冰下声源的分频段方位估计实验.研究结果表明,冰下声源方位估计的误差、准确率与检波器接收信号频段(或冰下声源信号频段)有关.采用低频段的接收信号进行方位估计时准确率较高,误差均值较小,所用接收信号频段≤250 Hz时,方位估计准确率可达72.9...     

北极典型冰下声信道建模及特性

将Burke-Twersky (BT)散射模型与射线理论相结合研究北极典型冰下的水声信道特性。BT模型将极地冰水界面的冰脊视为随机分布在自由表面的半椭圆柱。首先根据BT模型分别对高频和低频情况下的冰面反射系数取近似,计算不同频率的冰面反射系数。然后结合射线理论计算冰下声场并分析冰下信道特性,并与相同条件下绝对软界面的水声信道进行对比研究。结果显示,由于冰界面的存在,冰水界面与绝对软界面相比,冰面反射系数较小,使得部分声线不会传播很远,且随频率的增加衰减越发严重,因此不利于声信号远距离传播;此外在信道结构上,由于冰层反射系数较小,冰下信道多径相较于无冰的水-空气界面其多途现象不明显。研究结果对认知极地冰下水声信道特性以及开展极地水声系统性能预报具有一定意义。      

双基地冰-水界面混响强度的理论预报

针对北极冰层冰水界面具有小尺度粗糙界面的情况,给出由冰层造成的混响平均强度的理论预报公式。首先将北极冰层等效为具有粗糙界面的弹性介质,并且采用小粗糙度微扰理论在精细拟合粗糙度谱的基础上,建立粗糙冰层的三维散射强度模型,然后建立三维双基地声呐几何模型确定有效散射区域,最后给出双基地冰下混响平均强度的估算公式,并在所拟合的粗糙度谱的情况下,利用该预报公式计算双基地声呐配置参数和海冰物理及声学特性对冰下混响强度的影响算例。数值仿真表明该公式能够估算出北极冰下双基地声呐产生的混响平均强度,并且分析出了时延、基线长度等声呐配置参数和冰层声速比、密度比等海冰物理参数会对混响强度造成的影响。声呐的配置参数主要影响散射的有效面积,海冰的物理参数则影响着冰层的散射强度。其中,冰层声速比不仅影响混响强度的大小,还会影响混响强度随时间的衰减速度。      

采用被动声监测方法识别波弗特海区域海洋水声环境

为了研究北冰洋冰下水声环境的噪声特性,对2016年中国第七次北极科考期间在波弗特海进行的声学观测实验获取的数据集,采用时间统计分析和频域谱分析方法进行了处理,讨论了处理结果与同时期获取的海洋、大气之间的联系。针对冰下噪声长期监测和北冰洋水声环境特性的准实时观测,确定了描述冰下水声环境特性的参数组,给出了处理方法和流程,用于基于被动声监测的水声环境识别,指导研究设计和硬件选择。回传的实测结果可以与已发表的结论进行比较,从而确切描述和理解北冰洋水声环境的变化。     

水声学研究进展

声学是一门古老而又年轻的科学,水声学是声学的一个分支。本文介绍近年来水声学研究的主要进展。包括新型水声换能器材料、水中非线性声学、匹配场过滤、宽容性信号处理、水声通信、合成孔径成象技术、数据融合、声层析、水下ＧＰＳ技术等。文中还介绍了军事海洋学和基于模型的声呐设计等新概念。     

《水中目标声散射》

正科学出版社出版,2018年1月,北京,333页,定价:129元水中声学目标的回声或散射是有源声呐的信息源。由声呐方程知,在声呐工作的三大要素:目标特性、传输信道和接收、处理设备中,目标信息是声呐工作的基础。其中水下目标声散射的研究是最为实际应用所关注的,水声学著作,如R.J.尤立克《水声原理》、朱埜《主动声呐检测信息原理》等都设专门章节对水下目标声散射特性进行讨论。汤渭霖等《水中目标声散射》则为该领域第一部专门论著。     

北极海域海洋环境噪声建模与特性分析

北极海域海洋环境噪声的特殊性在于具有偶发的尖脉冲声，为分析其特性与规律，首先建模仿真分析不同脉冲噪声下高斯分布与α稳定分布的拟合效果，验证后者的鲁棒性。再从实测北极海域噪声中选取三种典型环境噪声为样本，通过对其非高斯性判定及不同分布模型对比，验证α稳定分布在北极海域环境噪声统计特性建模中的有效性，同时研究不同深度、不同频段对模型参数的影响，最后通过各月参数的统计结果与海冰密集度分析冰下噪声成因。由于通道数量有限，没有给出所有深度的变化规律。结果表明，北极海域冰下环境噪声具有明显脉冲成分和非高斯性，利用α稳定分布能更好的描述其统计特性；100Hz可作为冰下环境噪声脉冲性干扰源的划分界限；结冰期环境噪声具有强烈的非高斯性，而冰封期则高斯性较强。     

国内声学文献分类索引

(声学分类:0总类;1.物理声学22.水声学;3.机械振动学;4.噪声控制学55.超声学;6.语言声学; 7.生理声学;8.建筑声学Z 9.电声学;10.声学测试;11.大气声学5 12.地声学;13.生物声学;14.音乐声学;15.声信号处理) 0.总 类新型换能器及声基阵的发展概况,周福洪,郑士杰、姚青山,声学技术,9(1990),NO.4,1.航空声呐评述和展望,凌国民,声学与电子工程,1990,N。3,1.传声器的发展动向,张福学,电声技术,二990,N。 5,15.近代电声测量的主要思路,翁泰来,电声技术,1990,N。5,25. 2. 水 声 学厚度振动换能器脉冲响应的研究,郎益夫、蔡崇成、蒋桶祥等,声学技…     

Progresses and advances in Arctic underwater acoustics study

As a part of underwater acoustics, the study and development of Arctic Acoustics is later than underwater acoustics about several hundred years. After World War II, the study of Arctic Acoustics attracts many interests by some developed countries, especially U.S. and pre-Soviet Union. The research works obviously have some kinds of cold war brand. After the Cold War, with the gradual warming trend of Arctic area, the ocean acoustic environment in Arctic and its adjacent area have been considerably concerned. The 8 countries of Arctic rim organized exclusive "Arctic Council" in 1996. The white paper of "China Arctic Policy"was published in January 26, 2018, the Chinese government declared that China is a close Arctic country, and is the responsible stakeholder of Arctic interests. The new advances in Arctic research works axe introduced in this paper, including the results of scientific survey and studies about Arctic underwater acoustics of Chinese researchers. It is showed that the Arctic underwater acoustical research area is not only parallely copy the topics what traditional underwater acoustics covered, e.g. environment noise,reverberation,and propagation, but also the topics which is specifically based on the Arctic environment. Some of these research fields cannot be included in the traditional shallow water, deep water acoustics, e.g. the ice-water interface feature, ice covered semi-acoustic channel effect, the communication and navigation of UUV in the condition of under ice, and the adaptation of sonar technique, equipment in the ice-covered environment, etc.     

Features of underwater acoustics from Aristotle to our time

Underwater acoustics has been one of the fastest growing fields of research in acoustics. In particular, the 20th Century has taken our understanding of underwater acoustics phenomena a great step forward. The two World Wars contributed to the recognition of the importance of research in underwater acoustics, and the momentum in research and development gained during World War II did not reduce in the years after the war. The so-called cold war and the development in computer technology both contributed substantially to the development in underwater acoustics over the second half of the 20th Century. However, the very widespread field of underwater acoustic activities started nearly 2300 years ago with human curiosity about the fundamental nature of sound in the sea. From primitive philosophical and experimental studies of the velocity of sound in the sea and through centuries of successes and failures, the knowledge about underwater acoustics has developed into its high-technological status of today. In particular the development through the period from Aristotle (384–322 BC) to 1960 formed the basis for the tremendous research and development efforts we have witnessed in our time. In this paper most emphasis will be put on the development in underwater acoustics through this period of nearly 2300 years duration, and only the main trends in later research will be mentioned.     

Overview of a university course on acoustics and noise

The Bachelor of Mechanical Engineering at the University of New South Wales in Sydney, Australia is a four year degree program. In their fourth and final year, students can choose from a range of technical elective courses, one of those being in acoustics. The acoustics course entitled "Fundamentals of Noise" can also be taken as a postgraduate coursework subject as part of a Masters by Coursework degree. The course covers fundamental topics in acoustics, noise, noise measurement, and noise control. This paper outlines the topics covered in the course, the range of assessment activities conducted by the students, and the use of invited industry guest speakers, all of which aim to maximize student knowledge, interest, and performance in the course.     

Information for Contributors

<正>1 Chinese Journal of Acoustics is the publication of the Acoustical Society of China and the Institute of Acoustics, Chinese Academy of Sciences, to promote the international understanding and collaboration in the field of acoustics. It publishes original works in all branches of acoustics in China. Contributions from invited guests and friends overseas are also solicited.     

Information for Contributors

1 Chinese Journal of Acoustics is the publication of the Acoustical Society of China and The Institute of Acoustics, Academia Sinica, to promote the international understanding and collaboration in the field of acoustics. It publishes original works in all branches of acoustics in China. Contributions from invited guests and friends overseas are also solicited. 2 Contributed papers submitted for publication in the Journal should be original, unpub-     

Information for Contributors

1 Chinese Journal of Acoustics is the publication of the Acoustical Society of China and The Institute of Acoustics,Academia Sinica,to promote the international understanding and collaboration in the field of acoustics.It publishes original works in all branches of acoustics in China.Contributions from invited guests and friends overseas are also solicited.     

全国声学标准化技术委员会的发展与国家声学基础测量方法标准体系建设

首先回顾了全国声学标准化技术委员会自1980年成立以来,在国家声学标准制、修订方面所取得的一批重要的标准研究成果。经过全国声学领域历届委员和专家30年来的共同努力,截止2009年共制、修订声学方面国家标准166项次,形成了目前归口声标委管理的131项现行有效的国家标准,由此也建立了涵盖声学基础、噪声、建筑声学、超水声四大类标准的国家声学基础测量方法标准体系。这些声学基础测量方法标准体系与国家声环境质量、噪声排放等环保标准和工程建设标准、电声和音视频等标准共同构成了较为完整的国家声学标准体系。最后结合声标委今后要开展的标准工作,提出了进一步完善国家声学基础测量方法标准体系的细部构想,可以相信,将来随着这些标准的陆续出台,我国声学标准体系会更趋完善。      

人居声环境科学——亚热带建筑科学国家重点实验室近年研究进展

本文介绍华南理工大学亚热带建筑科学国家重点实验室建筑声学子实验室近年来在人居声环境科学领域所开展的研究工作及取得的研究进展。人居声环境科学涵盖建筑声学、环境声学及声景学三个分支学科,分别对应于人居环境科学的三个主干一级学科,即建筑学、城乡规划学及风景园林学。其研究目的在于体现对人们的听觉关怀,创造一个良好的人居声环境。     

Ray and wave chaos in problems of sound propagation in the ocean

In the 1990s, a new area of research appeared in underwater acoustics: the investigation of the chaotic behavior of ray trajectories in inhomogeneous waveguides. It was found that, at distances on the order of 1000 km, the ray chaos already is fully developed, and this phenomenon should be taken into account in describing long-range sound propagation in the ocean. The present review, using specific examples, describes the methods of theoretical studies of both the ray chaos and its manifestations at a finite wavelength, as well as the results obtained in this area of research.