海底电磁探测仪器的承压密封舱

在海底进行电磁场探测必须解决仪器的承压密封问题。密封舱的体重对海上投放作业的难易程度有直接影响。为协调设备安全与海上施工效率的一致性,对所研制的承压密封舱需进行合理设计,以较小的体积和重量实现所规定的承压指标。论述了海底电磁探测仪器的承压密封舱的可靠性设计方法、舱体内部的器件安装结构及海底测量过程,压力模拟试验表明所研制的承压密封舱已达到设计要求。     

Comparing palaeolimnological and instrumental evidence of climate change for remote mountain lakes over the last 200 years

This paper compares the palaeolimnological evidence for climate change over the last 200 years with instrumental climate data for the same period at seven European remote mountain lakes. The sites are Øvre Neådalsvatn (Norway), Saanajärvi (Finland), Gossenköllesee (Austria), Hagelseewli (Switzerland), Jezero v Ledvici (Slovenia), Estany Redó (Spain, Pyrenees), and Niné Terianske Pleso (Slovakia). We used multiple regression analysis to transfer homogenised lowland air temperature records to each of the sites, and these reconstructions were validated using data from on-site automatic weather stations. These data showed that mean annual temperature has varied over the last 200 years at each site by between 1 and 2 °C, typical of the high frequency variability found throughout the Holocene, and appropriate, therefore, to test the sensitivity of the various proxy methods used. Sediment cores from each site were radiometrically dated using ²¹⁰Pb, ¹³⁷Cs and ²⁴¹Am and analysed for loss-on-ignition, C, N, S, pigments, diatoms, chrysophytes, Cladocera and chironomids. Comparisons between the proxy data and the instrumental data were based on linear regression analysis with the proxy data treated as response variables and the instrumental data (after smoothing using LOESS regressions) as predictor variables. The results showed few clear or consistent patterns with generally low or very low r² values. Highest values were found when the data were compared after smoothing using a broad span, indicating that some of the proxy data were capturing climate variability but only at a relatively coarse time resolution. Probable reasons for the weak performance of the methods used include inaccurate dating, especially for earlier time periods, the influence of confounding forcing factors at some sites e.g., air pollution, earthquakes, and the insensitivity of some methods to low amplitude climate forcing. Nevertheless, there were trends in some proxy records at a number of sites that had a relatively unambiguous correspondence with the instrumental climate records. These included organic matter and associated variables (C and N) and planktonic diatom assemblages at the majority of sites and chrysophytes and chironomids at a few sites. Overall for longer term studies of the Holocene, these results indicate the need to be cautious in the interpretation of proxy records, the importance of proxy method validation, the continuing need to use reinforcing multi-proxy approaches, and the need for careful site and method selection.     

Hydrocarbon degraders from tropical marine environments

Analysis of 20 samples of marine mud and water around Mumbai resulted in the isolation of 17 bacteria and yeasts all of which were able to degrade more than 10% of the supplied crude oil. The yeasts strains were important degraders of the aliphatic fraction of crude. All the isolated yeasts belonged to the genus Candida. Using biochemical tests these were identified as Candida parapsilosis, C. albicans, C. guilliermondii, Yarrowia lipolytica, C. tropicalis and C. intermedia. Y. lipolytica was the best degrader utilizing 78% of the aliphatic fraction of Bombay High crude oil. None of these isolates degraded the aromatic or ashphaltene fractions. All the isolates required aeration, nitrogen and phosphate supplementation for optimal degradation. Four out of the six yeasts are human pathogens.     

中扬子区海相沉积盆地性质研究

分析了中扬子区海相沉积盆地基底和层序充填特性;研制了M判别图解,研究了沉积盆地的性质,认为盆地基底具有三分性,盆地层序充填具有阶段性和分区性,沉积盆地主体具有克拉通盆地的特点和性质。     

莺歌海盆地海相生物气特征及生化成气模式

莺歌海盆地浅层第四系-上新统存在丰富的生物气资源,已发现生物气的组成以甲烷和氮为主、干燥系数高达0.99,甲烷碳同位素轻(-65.57‰～-63.14‰)尤其是氢同位素偏重(-172.1‰～-108.5‰)是该区生物气的重要特点.研究表明,该区第四系-上新统海相沉积有机质是生物气的基质,这套源岩的平均有机碳含量约0.4%,有机质中细菌可利用基质以粗纤维、半纤维素和蛋白质为主,特别是有机质生化代谢过程中的中间产物-氨基酸、乙酸含量异常高,揭示其正处在活跃的生化成气时期;根据模拟实验结果结合本区的地质条件,初步确定生物气生成的主带在35～65℃之间、生化成气下限深度约为85℃(对应井深约2000 m,实际埋深1900 m左右),进而建立了海相生物气的形成演化模式。     

多重分形在海积软土微观结构研究中的应用

本文将多重分形谱引入到土微观结构分形研究中,对天津市滨海新区三个不同地点海积软土原状样及不同固结压力后土中孔隙的多重分形特征进行研究,从多重分形的角度对孔隙的不均匀性进行定量描述,并建立孔隙多重分形谱各特征参数与荷载之间的关系.结果表明三个地点的海积软土孔隙多重分形特征存在差异.     

参考文献著录规则应用及注意的问题

通过对《文后参考文献著录规则》的学习和理解,阐明参考文献著录方法,列举了有关著录事例和著录时应注意的问题。为著者撰写学术论文提供参考,以便提高学术论文和科技期刊质量。     

Brest sea level record: a time series construction back to the early eighteenth century

The completeness and the accuracy of the Brest sea level time series dating from 1807 make it suitable for long-term sea level trend studies. New data sets were recently discovered in the form of handwritten tabulations, including several decades of the eighteenth century. Sea level observations have been made in Brest since 1679. This paper presents the historical data sets which have been assembled so far. These data sets span approximately 300 years and together constitute the longest, near-continuous set of sea level information in France. However, an important question arises: Can we relate the past and the present-day records? We partially provide an answer to this question by analysing the documents of several historical libraries with the tidal data using a ‘data archaeology’ approach advocated by Woodworth (Geophys Res Lett 26:1589–1592, 1999b). A second question arises concerning the accuracy of such records. Careful editing was undertaken by examining the residuals between tidal predictions and observations. It proved useful to remove the worst effects of timing errors, in particular the sundial correction to be applied prior to August 1, 1714. A refined correction based on sundial literature [Savoie, La gnomique, Editions Les Belles Lettres, Paris, 2001] is proposed, which eliminates the systematic offsets seen in the discrepancies in timing of the sea level measurements. The tidal analysis has also shown that shallow-water tidal harmonics at Brest causes a systematic difference of 0.023 m between mean sea level (MSL) and mean tide level (MTL). Thus, MTL should not be mixed with the time series of MSL because of this systematic offset. The study of the trends in MTL and MSL however indicates that MTL can be used as a proxy for MSL. Three linear trend periods are distinguished in the Brest MTL time series over the period 1807–2004. Our results support the recent findings of Holgate and Woodworth (Geophys Res Lett) of an enhanced coastal sea level rise during the last decade compared to the global estimations of about 1.8 mm/year over longer periods (Douglas, J Geophys Res 96:6981–6992, 1991). The onset of the relatively large global sea level trends observed in the twentieth century is an important question in the science of climate change. Our findings point out to an ‘inflexion point’ at around 1890, which is remarkably close to that in 1880 found in the Liverpool record by Woodworth (Geophys Res Lett 26:1589–1592, 1999b).     

南海1∶100万永暑礁幅海洋区域地质调查成果

1∶100万永暑礁幅海洋区域地质调查成果揭示了该区地壳的浅、中、深层地质特征。浅层主要研究海底地形、地貌、表层沉积物、矿产资源、潜在地质灾害等；中层主要研究新生代地层、断裂体系、岩浆岩、含油气盆地远景等；深层则研究磁性基底、深层断裂、莫霍面分布特征等。本成果在以下几方面有重要突破：①通过对比新生代以来的地层,确定各沉积盆地地层特征和相互关系,在此基础上预测油气资源前景；②分析表层沉积物类型,预测本区未来可能具有开发价值的固体矿产资源；③利用磁性基底和莫霍面数据分析本区地壳结构特征。