冰岛地热资源的开发利用

地球内部蕴藏着难以想象的巨大的地热能量,地热资源由于储量巨大,相对于石油、煤炭等能源,对环境的负面影响小,因此被世界各国公认为可再生清洁能源,并逐渐成为重点研究开发的新能源。地热资源虽然蕴藏丰富,但在世界各地的分布不均匀,有些国家地热资源特别丰富,全球富地热资源的国家应首届冰岛。     

中国磁性构造学的进展（下）

四、河北省迁安矿区柳河峪断裂的磁组构研究迁安矿区位于河北省迁安县的西部。其范围北起水厂,南至佛峪院;西以震旦系盖层为界,东到滦河。南北长27公里。东西宽8—13公里,面积约为300平方公里。矿区处于华北地台北缘,燕山沉降带的迁安隆起西部边缘的褶皱带中。区内广泛出露太古界变质岩系和震旦系长石石英砂岩。此外还有少量侏罗系和老第三系地层。矿区断裂构造类型及先后期次较多,对矿体的影响也较大。从变形机制上看,有韧性断裂和脆性断裂两种。从改造关系来划分可分成愈合型断裂和复合型断裂两种。其形成年代为前中元古和后中元古两种:前者一般为韧性断裂和愈合型断裂,后者一般为脆性断裂和复合型断裂。     

月壤双轴试验的剪切带离散元数值分析

土体的破坏问题一般都是从其剪切带入手进行研究的。针对真实月壤所处的环境（无水、低重力场、低气压等）和内摩擦角较大的特点,采用最近提出的1种考虑粒间抗转动作用与粒间范德华力2个因素的月壤散粒体力学接触模型,用离散单元法模拟了柔性边界条件下月球环境（含范德华力）与地球环境（不含范德华力）2种试样的双轴压缩试验,通过试样局部变形、速度场、孔隙比及转动场的变化情况研究了2种试样剪切带形成与发展。研究结果表明,剪切带的形成是试样内部应变局部化的结果,同时也伴随着试样内部颗粒相对转动的局部化,月面环境对试样的破坏形式与性状（剪切带的倾角及厚度）有显著的影响,探月工程中必须考虑到月面环境对月壤力学性质的影响。     

南水北调渠坡膨胀土胀缩特性及变形模型研究

南水北调工程膨胀土渠坡变形受大气降雨、蒸发等干湿循环作用较为显著,揭示渠顶膨胀土在干湿循环作用下的胀缩变形和垂直位移变形特征,可为渠坡的稳定性评价与处治方案提供依据。利用膨胀土室内胀缩特性试验结果,结合垂直位移量、含水率、降雨量、蒸发量和气温监测等现场观测数据,分析渠顶位移量和影响因子间关联度,建立了干湿循环作用下渠顶膨胀土的竖向变形模型。研究结果表明,以含水率、降雨量、蒸发量等构成的胀缩因子与渠顶垂直位移呈负相关关系,胀缩因子引起垂直位移分量较小;温度因子与渠顶垂直位移呈正相关关系,对渠顶垂直变形有较大影响,是影响渠顶变形的主要因素;渠坡开挖（时效因子）在施工初期对渠顶垂直变形有一定的影响,开挖完成后对渠顶垂直变形影响甚微。     

2008年夏季加拿大海盆永久冰区的淡水累积现象

A combination of δ~(18)O and salinity data was employed to explore the freshwater balance in the Canada Basin in summer 2008.The Arctic river water and Pacific river water were quantitatively distinguished by using different saline end-members.The fractions of total river water,including the Arctic and Pacific river water,were high in the upper 50 m and decreased with depth as well as increasing latitude.In contrast,the fraction of Pacific river water increased gradually with depth but decreased toward north.The inventory of total river water in the Canada Basin was higher than other arctic seas,indicating that Canada Basin was a main storage region for river water in the Arctic Ocean.The fraction of Arctic river water was higher than Pacific river water in the upper 50 m while the opposite was true below 50 m.As a result,the inventories of Pacific river water were higher than those of Arctic river water,demonstrating that the Pacific inflow through the Bering Strait is the main source of freshwater in the Canada Basin.Both the river water and sea-ice melted water in the permanent ice zone were more abundant than those in the region with sea-ice just melted.The fractions of total river water,Arctic river water,Pacific river water increased northward to the north of 82°N,indicating an additional source of river water in the permanent ice zone of the northern Canada Basin.A possible reason for the extra river water in the permanent ice zone is the lateral advection of shelf waters by the Trans-Polar Drift.The penetration depth of sea-ice melted waters was less than 30 m in the southern Canada Basin,while it extended to 125 m in the northern Canada Basin.The inventory of seaice melted water suggested that sea-ice melted waters were also accumulated in the permanent ice zone,attributing to the trap of earlier melted waters in the permanent ice zone via the Beaufort Gyre.     

热带北太平洋西部固氮速率及固氮微生物组成

In the present study, we report N_2 fixation rate(~(15)N isotope tracer assay) and the diazotroph community structure(using the molecular method) in the western tropical North Pacific Ocean(WTNP)(13°–20°N, 120°–160°E). Our independent evidence on the basis of both in situ N_2 fixation activity and diazotroph community structure showed the dominance of unicellular N_2 fixation over majority of the WTNP surface waters during the sampling periods.Moreover, a shift in the diazotrophic composition from unicellular cyanobacteria group B-dominated to Trichodesmium spp.-dominated toward the western boundary current(Kuroshio) was also observed in 2013. We hypothesize that nutrient availability may have played a major role in regulating the biogeography of N_2 fixation.In surface waters, volumetric N_2 fixation rate(calculated by nitrogen) ranged between 0.6 and 2.6 nmol/(L·d) and averaged(1.2±0.5) nmol/(L·d), with 10 μm size fraction contributed predominantly(88%±6%) to the total rate between 135°E and 160°E. Depth-integrated N_2 fixation rate over the upper 200 m ranged between 150 μmol/(m~2·d)and 480 μmol/(m~2·d)(average(225±105) μmol/(m~2·d). N_2 fixation can account for 6.2%±3.7% of the depthintegrated primary production, suggesting that N_2 fixation is a significant N source sustaining new and export production in the WTNP. The role of N_2 fixation in biogeochemical cycling in this climate change-vulnerable region calls for further investigations.     

楚科奇和西伯利亚陆架颗粒有机物的来源：碳、氮同位素的线索

The stable isotopic composition(δ~(13)C and δ~(15)N) and carbon/nitrogen ratio(C/N) of particulate organic matter(POM) in the Chukchi and East Siberian shelves from July to September, 2016 were measured to evaluate the spatial variability and origin of POM. The δ~(13)C_(POC) values were in the range of -29.5‰ to-17.5‰ with an average of -25.9‰±2.0‰, and the δ~(15)N_(PN) values ranged from 3.9‰ to 13.1‰ with an average of 8.0‰±1.6‰. The C/N ratios in the East Siberian shelf were generally higher than those in the Chukchi shelf, while the δ~(13)C and δ~(15)N values were just the opposite. Abnormally low C/N ratios(4), low δ~(13)C_(POC)(almost-28‰) and high δ~(15)N_(PN)(10‰) values were observed in the Wrangel Island polynya, which was attributed to the early bloom of small phytoplankton. The contributions of terrestrial POM, bloom-produced POM and non-bloom marine POM were estimated using a three end-member mixing model. The spatial distribution of terrestrial POM showed a high fraction in the East Siberian shelf and decreased eastward, indicating the influence of Russian rivers. The distribution of non-bloom marine POM showed a high fraction in the Chukchi shelf with the highest fraction occurring in the Bering Strait and decreased westward, suggesting the stimulation of biological production by the Pacific inflow in the Chukchi shelf. The fractions of bloom-produced POM were highest in the winter polynya and gradually decreased toward the periphery. A negative relationship between the bloom-produced POM and the sea ice meltwater inventory was observed, indicating that the net sea ice loss promotes early bloom in the polynya.Given the high fraction of bloom-produced POM, the early bloom of phytoplankton in the polynyas may play an important role on marine production and POM export in the Arctic shelves.     

劳动保护工作的现代发展趋势

介绍俄罗斯联邦在劳动保护方面的这一立法,指出劳动保护工作在组织方面不足。介绍欧洲联盟国家召开的国劳保大会以及欧洲议会专门委员会制定的１９９６￣２０００年作业工地工作安全、卫生和健康保护规划。介绍了俄罗斯地矿系统劳动保护工作现状,提出了改善劳保工作的措施和科技规划的主要方向。     

西太平洋地区DMS及其他硫化物的观测研究

1991年9～10月中,美在西太平洋区域进行了PEM-WEST-A考察,从中选取其飞行观测资料中的硫化物(主要包括DMS、SO₂、OCS和CS₂4种硫化物)进行了硫化物的垂直分布分析,并结合气象资料和轨迹分析估计西太平洋大气中硫化物的源。结果表明,DMS在观测区域的通量较小,这与此地区低的生物产率有关;而且随着高度的升高,DMS浓度降低。由SO₂的浓度廓线可看出,在边界层及对流层下部,随着高度的升高,SO₂略有减少,但在对流层中部增多甚快。海洋大气中,OCS浓度很高(约为500×10-12),且很稳定,它不随纬度、高度变化。CS₂浓度很低,其浓度随高度变化趋势不明显。     

生态移民前、后神农架大九湖沼泽内锯齿藓中的重金属含量变化

苔藓作为监测大气污染的指示生物,在国内外被广泛应用于研究大气重金属沉降分布。为了研究神农架大九湖沼泽生态移民前、后大气重金属沉降变化状况,于2012年7月29日和2016年10月25日,在野外采集锯齿藓(Prionidium setschwanicum)样品,并测定其中的As、Cd、Cr、Co、Cu、Fe、Pb和Zn的含量,分析生态移民前、后大九湖沼泽锯齿藓中8种重金属的含量变化。研究结果表明,生态移民4 a后,锯齿藓中As、Cd、Cr、Cu、Pb和Zn含量都显著减少,分别减少了100%、43%、68%、42%、56%和76%。这与生态移民后该区人类活动减少有关,虽然仍存在因少量旅游交通造成的大气重金属沉降,但是,相对生态移民前,大九湖沼泽的大气环境质量得到了一定程度的改善。