鹿科动物发情期叫声的研究进展

声音通讯是动物交流个体信息的五大通讯方式之一,围绕鸟类、两栖类、鲸目、翼手目等以声音通讯为主要交流方式的动物相关研究多聚焦在叫声特征、产生机制、物种演化等研究内容。鹿科(Cervidae)动物雄性个体在发情期叫声音调多变,种间差异明显,是研究鹿科动物种间和种内声音变异及解剖学机制的理想群体。文章基于各项国内外鹿科动物发情期的叫声研究,列举雄鹿发情期声音通讯行为的差异,并对发情期叫声进行了分类,总结鹿发声结构研究现状、鹿科动物在雄性竞争与雌性选择中对雄鹿叫声的基频和共振峰的不同偏好,以及基频与共振峰在传达信息时的种间差异。此外,文章还探讨了杂交鹿在叫声发育与性选择偏好演化等方面的研究。

Influence of temperature on acoustic emission source location accuracy in underground structure

An acoustic emission(AE)experiment was carried out to explore the AE location accuracy influenced by temperature.A hollow hemispherical specimen was used to simulate common underground structures.In the process of heating with the flame,the pulse signal of constant frequency was stimulated as an AE source.Then AE signals received by each sensor were collected and used for comparing localization accuracy at different temperatures.Results show that location errors of AE keep the same phenomenon in the early and middle heating stages.In the later stage of heating,location errors of AE increase sharply due to the appearance of cracks.This provides some beneficial suggestions on decreasing location errors of structural cracks caused by temperature and improves the ability of underground structure disaster prevention and control.

Characteristics of acoustic emission temporal sequences during the failure of a concrete structure under loading

The characteristics of acoustic emission (AE) signals given off in the course of the failure of a concrete structure is explored based on the laboratory experiments with concrete specimens. It is observed that the failure of a concrete structure experiences three stages divided by two inflexion points on the AE event curve, which are sequentially no damage, damage initiation and propagation, and major failure stages. In the first stage, existing micro cracks and defects are compacted by loading, but no damage propagated, hence few AE signals are detected, and it appears that there exists a nearly linear relationship between the relative stress and relative strain. In the second stage, the AE event frequency increases, implying that micro cracks begin to emerge inside the concrete structure, which is consistent with the damage mechanics. When the load is over 80 % of that breaks the structure, i.e. the maximum load, there is a vertical jump on the AE event count curve, which suggests that the failure propagation speeds up. After the second inflexion point, the AE event density increases faster than before, and there is another jump just before breaking, which indicates a quick propagation stage. These findings are valuable for evaluating the damage situations, and for studying and monitoring the dynamic process of the failure behaviors of a concrete structure.

Research on vibration and near-field sound radiation of ring-ribbed cylindrical shell coated deadening and decoupling materials

The research on structural vibration and sound radiation of underwater ring-ribbed cylindrical shell, which is coated with a kind of deadening and decoupling materials, becomes a focus in recent years. This paper analyzes the problem on two aspects: model experiment and numerical calculation. The model experiment is carried out including three cases firstly, in which the structural vibration response and radiating acoustic field are measured respectively, and the results gained in these three cases are analyzed to discuss the effect of reducing structural vibration and radiating noise of the deadening and decoupling materials. The coupling FEM/BEM and the SEA methods are both used in numerical calculation, i.e. the arithmetic of the coupling FEM/BEM method is adopted to calculate the low frequency characteristics and the SEA method is adopted to calculate the medium-high frequencies characteristics of the model. By comparing experimental results with numerical calculation results, it is proved that the algorithm adopted in this paper is reasonable.

An explosive seismic sounding profile across the transition zone between west Kunlun Mts. and Tarim Basin

The explosive seismic sounding profile across the transition zone from the west Kunlun Mts. to the Tarim Basin revealed the complex deep structure formed by continent-continent collision on the northern margin of the Tibetan Plateau. The profile shows that the attitude of the Moho is in agreement with that of the crystalline basement in the Tarim Basin and the whole crust dips as a thick slate southwards with an angle from 5° to 7°. Meanwhile, the Moho depth increases from 40 km to 57 km within a distance of 150 km in the southern Tarim region, depicting the subduction of the crust of this region towards the west Kunlun Mts. The crust of the northern slope of the west Kunlun Mts. shows an evident compressed and shortened feature, that is, the basement is uplifted, the interface dips northwards and the Moho rises abruptly to become flat, so that the lower crust is as thick as 20 km.

What makes a cry a cry？ A review of infant distress vocalizations

In contrast to the cries of human infants, sounds made by non-human infants in different stressful behavioral contexts （hunger or physical discomfort, isolation, capture by humans or predators） are usually treated as distinct types of vocalizations. However, if distress vocalizations produced by different species and in different contexts share a common motivational state and associated neurochemical pathways, we can expect them to share a common acoustic structure and adaptive function, showing only limited variation that corresponds to the infant＇s level of arousal. Based on this premise, we review the acoustic structure and adaptive function of two types of distress calls, those given when infants were isolated from their mothers （isolation caUs） or captured by humans （capture calls）. We conducted a within-context comparison examining the two call types across a diverse se- lection of mammalian species and other vertebrate groups, followed by a comparison of how acoustic structure and function dif- fers between these contexts. In addition, we assessed acoustic traits that are critical to the response of caregivers. Across verte- brate species, distress vocalizations produced in these two behavioral contexts tend to be tonal with a simple chevron, flat or de- scending pattern of frequency modulation. Reports that both isolation and capture calls of vertebrate infants serve to attract care- givers are universal, and the fundamental frequency of infant vocalizations is often critical to this response. The results of our re- view are consistent with the hypothesis that differences in the acoustic structure of isolation and capture distress vocalizations re- flect differences in arousal, and not discrete functions. The similarity in acoustic structure and caregiver response observed across vertebrates adds support to the hypothesis that the production and processing of distress vocalizations are part of a highly-conserved system of social vocal behaviour in vertebrates. Bioacoustic research may move forward by recognizing the commonality among different forms of infant solicitations that attract caregivers, and the commonality of these solicitations with vocalizations that attract conspecifics in still other behavioral contexts [Current Zoology 58 （5）： 698-726, 2012].

An FBG acoustic emission source locating system based on PHAT and GA

Using the acoustic emission locating technology to monitor the health of the structure is important for ensuring the continuous and healthy operation of the complex engineering structures and large mechanical equipment. In this paper, four fiber Bragg grating(FBG) sensors are used to establish the sensor array to locate the acoustic emission source. Firstly, the nonlinear locating equations are established based on the principle of acoustic emission, and the solution of these equations is transformed into an optimization problem. Secondly, time difference extraction algorithm based on the phase transform(PHAT) weighted generalized cross correlation provides the necessary conditions for the accurate localization. Finally, the genetic algorithm(GA) is used to solve the optimization model. In this paper, twenty points are tested in the marble plate surface, and the results show that the absolute locating error is within the range of 10 mm, which proves the accuracy of this locating method.