Navy sonar and cetaceans: just how much does the gun need to smoke before we act?

Cetacean mass stranding events associated with naval mid-frequency sonar use have raised considerable conservation concerns. These strandings have mostly involved beaked whales, with common pathologies, including "bubble lesions" similar to decompression sickness symptoms and acoustic traumas. However, other cetacean species have also stranded coincident with naval exercises. Possible mechanisms for the strandings include a behavioral response that causes deep divers to alter their diving behavior, which then results in decompression sickness-like impacts. Current mitigation measures during military exercises are focused on preventing auditory damage (hearing loss), but there are significant flaws with this approach. Behavioral responses, which occur at lower sound levels than those that cause hearing loss, may be more critical. Thus, mitigation measures should be revised. A growing number of international bodies recognize this issue and have urged increasing scrutiny of sound-producing activities, but many national jurisdictions have resisted calls for increased protection.     

清江流域汛期暴雨短期预报数理统计模型

利用天气预报基本原理和方法,从天气学角度出发,在历史天气图上(1990～2000年)寻找清江流域汛期(5～9月)暴雨发生的天气系统,配以局地大气能量,对照清江流域汛期逐日面雨量资料,从中找出物理意义明确、相关性较好的预报因子,应用数理统计方法,建立清江流域汛期暴雨短期预报数理统计模型。经检验,该预报模型具有一定的实用性。     

海试引发深水油气综合地球物理采集的几点思考

深水地球物理采集技术随着国际海洋油气勘探的不断升温,技术水平不断提高.本文结合我国的地球物理海试实践,提出深水油气综合地球物理采集的几点思考,地震采集参数的选择,重磁震采集过程的实时监控,总结海试过程深水地球物理采集的两方面进展,一是精确定位的长缆二维地震采集技术,二是高精度的重磁震联合质量监控的综合地球物理测量技术,为深水油气勘探提供采集技术保障.     

光纤测量技术在岩土工程量测中的应用

光纤作为传感与传输双重功能的特殊介质,所具有显著优势使其在岩土工程量测中有着十分广阔的应用前景。在介绍光纤传感器与系统和光纤微弯测量原理的基础上,以边坡变形量测为例,结合岩土工程中对应力应变、压力位移等多种参量的量测要求,探讨了光纤位移传感器制作及布设方法,深入分析了其在边坡变形量测中需要解决的关键技术问题和解决办法,给出了构建超长距全分布式光纤量测系统的基本模式和主要架构。     

A synthesis of dominant ecological processes in intensive shrimp ponds and adjacent coastal environments in NE Australia

One of the key environmental concerns about shrimp farming is the discharge of waters with high levels of nutrients and suspended solids into adjacent waterways. In this paper we synthesize the results of our multidisciplinary research linking ecological processes in intensive shrimp ponds with their downstream impacts in tidal, mangrove-lined creeks. The incorporation of process measurements and bioindicators, in addition to water quality measurements, improved our understanding of the effect of shrimp farm discharges on the ecological health of the receiving water bodies. Changes in water quality parameters were an oversimplification of the ecological effects of water discharges, and use of key measures including primary production rates, phytoplankton responses to nutrients, community shifts in zooplankton and delta15N ratios in marine plants have the potential to provide more integrated and robust measures. Ultimately, reduction in nutrient discharges is most likely to ensure the future sustainability of the industry.     

Modelling of hydrodynamics and cohesive sediment transport in Tanshui River estuarine system,Taiwan

A laterally averaged two-dimensional numerical model is used to simulate hydrodynamics and cohesive sediment transport in the Tanshui River estuarine system. The model handles tributaries as well as the main stem of the estuarine system. Observed time series of salinity data and tidally averaged salinity distributions have been compared with model results to calibrate the turbulent diffusion coefficients. The overall model verification is achieved with comparisons of residual currents and salinity distribution. The model reproduces the prototype water surface elevation, currents and salinity distributions. Comparisons of the suspended cohesive sediment concentrations calculated by the numerical model and the field data at various stations show good agreement. The validated model is applied to investigate the tidally averaged salinity distributions, residual circulation and suspended sediment concentration under low flow conditions in the Tanshui River estuarine system. The model results show that the limit of salt intrusion in the mainstem estuary is located at Hsin-Hai bridge in Tahan Stream, 26 km from the River mouth under Q75 flow. The null point is located at the head of salt intrusion, using 1 ppt isohaline as an indicator. The tidally averaged sediment concentration distribution exhibits a local maximum around the null point.     

旅大50号金伯利岩管中金刚石谱学特征及地质意义

通过矿物谱学的方法对放大５０号金伯利岩管中不同晶形金刚石进行研究。结果表明，不同晶形金刚石中杂质种类、含量及结构上存在很大差异。其中，发现Ｎ杂质中有“Ｎ≡Ｎ”结构形式，且随晶体形态的变化而变化，那是其来源深度及所经历的过程不同所致。本文阐述了它们的地质意义。     

相关系数稳定性检验及其在水文地质学中的应用

在利用相关分析预报地下水动态变化的过程中,由于忽视了回归方程中相关系数稳定性问题,经常会得到不理想的预报结果。本文在系统地介绍相关系数稳定性检验方法的基础上,通过对甘肃省武威盆地地下水动态变化的预报检验,提出了解决这一问题的办法,即分段截取法。该法使采用相关分析对地下水动态变化做出较高水平的预报成为可能,该法既简单又实用。