机场航空噪声暴露-反应关系分析

本文利用我国的机场航空噪声评价量一计权等效连续感觉噪声级LWECPN和机场周边社区遭受机场噪声强烈干扰的人群比例PHA对机场航空噪声的暴露-反应关系进行了详细分析，得到了LWECPN～PHA关系式和关系曲线，并对LWECPN～PHA关系特点进行了分析。     

我国机场噪声评价量与噪声影响的定量关系

本文对我国机场航空噪声评价量LWECPN(计权等效连续感觉噪声级)与国外常用的评价量LDN(昼夜等效声级)的内涵进行了分析，导出了两者之间的关系，并借助这一关系和国外研究成果得到了机场周边社区人群中受到航空噪声强烈干扰的人数比例与LWECPN的关系式。     

Aircraft noise annoyance at three joint air carrier and general aviation airports

The results of social surveys conducted near three airports that support both general aviation and scheduled air carrier operations are presented and discussed. Inferences supported by these data include: The nature of noise exposure and community reaction at smaller airports may differ from that at larger airports; survey techniques are capable of identifying changes in annoyance associated with numerically small changes in noise exposure; changes in the prevalence of annoyance are causally produced by changes in noise exposure; and changes in annoyance associated with changes in exposure vary with time.     

城市道路交通噪声烦恼度社会调查

本文以烦恼度为主观反应指标,采用三种5级程度衡量尺度,对西安市内三条主要干道和两类典型交叉口附近区域内的道路交通噪声进行了烦恼度问卷调查。此次调查针对人口统计学因素(性别、年龄、文化程度、身体健康状况)上的个体差异与等级描述词不同的程度尺度可能对道路交通噪声烦恼度调查结果的影响,以及特定路况条件下的噪声烦恼度与不同机动车辆的行驶噪声烦恼度展开了研究。通过对调查数据的分析处理,发现并初步总结出:与选取不同的烦恼度尺度相比,人口统计学因素对调查结果的影响更加显著;人口统计学因素与特定路况条件下的噪声烦恼度及不同机动车辆的行驶噪声烦恼度无明显相关;但不同机动车辆的行驶噪声烦恼度不同,实际研究中需对摩托车噪声加以重视并区别对待。     

Effect of flight path dispersion on airport noise

The social impact of aircraft noise is usually assessed by way of estimates of the “energy sum” of noise delivered to points on the ground. Though in such estimates one commonly supposes that the noise generating aircraft fly along specific trajectories, it has been shown that statistical dispersion about the mean flight path can be significant. The literature suggests that the effect is dominated by lateral excursions due to fluctuations in heading during departure.In this paper an additive term is presented to correct “energy sum” based noise indices for lateral flight path dispersion. Gaussian distribution of flight paths and logarithmic decay of noise level are assumed in the mathematical model. Under these conditions, the correction term depends only on the horizontal and vertical distances between the observer and the closest point on the mean flight path, both distances being normalized by the standard deviation of the lateral fluctuations.The limited data that have been reported indicate that the standard deviation tends to grow linearly with distance after liftoff. If so, the correction for a given aircraft category will tend to be constant along lines radiating outward from the lift-off point. Lateral dispersion always reduces the noise index along the ground track. This reduction decreases to either side, vanishing at some 3 to 6 degrees azimuth. For larger azimuth angles, dispersion increases noise energy-the maximum occurring at some 10 degrees. In typical airport situations this maximum increase may be as great as four decibels. Accordingly, as these results represent a lower bound for them, dispersive effects may significantly influence airport exposure.A numerical example illustrates how lateral flight path dispersion broadens and foreshortens contours of equal noise exposure.     

关于噪声社会反应测定方法的国际共同研究——中国语噪声调查问题和评价尺度的建构

在有关噪声问题的社会调查中,由于不同的研究者采用了不同的调查问题和反应尺度,使得这些研究结果难以进行比较和借鉴。为了解决这个问题,ICBEN Team 6提出了制订标准的噪声社会反应测定方法的提案。本文就是在国际噪声联合专家研究结果的基础上,尝试建立中国语标准噪声调查问题和5级噪声反应言语尺度。     

A measurement model for general noise reaction in response to aircraft noise

In this paper a measurement model for general noise reaction (GNR) in response to aircraft noise is developed to assess the performance of aircraft noise annoyance and a direct measure of general reaction as indicators of this concept. For this purpose GNR is conceptualized as a superordinate latent construct underlying particular manifestations. This conceptualization is empirically tested through estimation of a second-order factor model. Data from a community survey at Frankfurt Airport are used for this purpose (N=2206). The data fit the hypothesized factor structure well and support the conceptualization of GNR as a superordinate construct. It is concluded that noise annoyance and a direct measure of general reaction to noise capture a large part of the negative feelings and emotions in response to aircraft noise but are unable to capture all relevant variance. The paper concludes with recommendations for the valid measurement of community reaction and several directions for further research.     

Shot noise measurements in a wide-channel transistor near pinch-off

We study a shot noise of a wide channel gated high-frequency transistor at a temperature of 4.2 K near pinch-off. In this regime, a transition from the metallic to the insulating state is expected to occur, accompanied by the increase in the partition noise. The dependence of the noise spectral density on current is found to be slightly nonlinear. At low currents, the differential Fano factor is enhanced compared to the universal value 1/3 for metallic diffusive conductors. We explain this result by the effect of thermal fluctuations in a nonlinear regime near pinch-off, without calling for the enhanced partition noise.     

Predictions of noise disturbance near large airports

This report examines the relationship between public annoyance with aircraft noise, objective measures of the noise itself, and mediating social or psychological conditions which affect the noise-annoyance relationship.     

Conformal field theories near a boundary in general dimensions

The implications of restricted conformal invariance under conformal transformations preserving a plane boundary are discussed for general dimensions d. Calculations of the universal function of a conformal invariant ξ which appears in the two-point function of scalar operators in conformally invariant theories with a plane boundary are undertaken to first order in the ge = 4 − d expansion for the operator φ² in φ⁴ theory. The form for the associated functions of ξ for the two-point functions for the basic field φ^α and the auxiliary field λ in the N → ∞ limit of the O(N) nonlinear sigma model for any d in the range 2 < d < 4 are also rederived. These results are obtained by integrating the two-point functions over planes parallel to the boundary, defining a restricted two-point function which may be obtained more simply. Assuming conformal invariance this transformation can be inverted to recover the full two-point function. Consistency of the results is checked by considering the limit d → 4 and also by analysis of the operator product expansions for φ^αφ^β and λλ. Using this method the form of the two-point function for the energy-momentum tensor in the conformal O(N) model with a plane boundary is also found. General results for the sum of the contributions of all derivative operators appearing in the operator product expansion, and also in a corresponding boundary operator expansion, to the two-point functions are also derived making essential use of conformal invariance.     

Effects of cessation of late-night flights on an airport community

A telephone survey was conducted to assess the effects of cessation of late-night overflights on communities to the east of Los Angeles International Airport. A total of approximately 1400 interviews were conducted before, immediately after, and a month after the cessation of flights. No appreciable effects were observed in terms of reduction of annoyance, or lessened speech or sleep interference. However large, consistent and statistically significant differences in response patterns as a function of level of noise exposure were observed both before and after cessation of late-night flights.These results can be accounted for either in terms of the relatively small decrease in 24-hour exposure that the elimination of flights between 23.00 and 06.00 hours represented, or in the light of a parallel study which failed to show recovery in the abnormal sleep patterns of long term area residents. The significance of these data for such issues as the proper weighting of nocturnal noise events or the appropriate weighting for numbers of events depends on which of the two alternative interpretations is favored.     

A Canadian national survey of attitudes and knowledge regarding preventive vaccines

Background  

Vaccines have virtually eliminated many diseases, but public concerns about their safety could undermine future public health initiatives.     

Quantum shot noise of conductors and general noise measurement methods

We review the quantum noise properties of phase coherent conductors, in particular the spectacular noise suppression associated with conductance quantization. We describe general techniques used to measure the tiny quantum shot noise current fluctuations at sub-kelvin temperature for low and high frequency.     

On the possible mechanism of the jet noise intensification near a wing

A qualitative model of the mechanism of intensification of jet noise issuing from a nozzle located near a wing is proposed. A two-dimensional model problem on the diffraction of a plane acoustic wave at the edge of a nozzle nozzle located near a half-plane simulating the wing edge is formulated. It is shown that diffraction on the wing edge of Kelvin-Helmholtz instability waves developing from the edge of the nozzle can lead to the significant intensification of the acoustic energy radiated into the far field.