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991.
992.
利用2008年夏季我国第3次北极科学考察资料,基于流式细胞技术,对白令海北部陆架区的微微型浮游植物丰度、细胞大小(碳含量)、色素浓度的分布特征进行了分析,并对该类群的环境适应性进行了研究。结果表明,微微型浮游植物中仅含聚球藻和真核藻,其丰度范围分别为0.14×106 2.69×106和0.23×106-12.49×106个/dm3。聚球藻的叶绿素a和藻红蛋白含量、微微型真核藻的叶绿素a含量与类群丰度以及微微型真核藻的类胡萝卜素含量与细胞大小间均存在同向变化趋势。两类藻偏向于喜温嗜淡型,更适合在寡营养环境中保持较高的丰度,但能在高营养盐浓度下形成相对较高的碳含量。越接近陆地,细胞越小,丰度越大,碳含量及FL2/FL3越低;所处层位越深、纬度越高,则细胞越大,碳含量及FL2/FL3越高。北极气温升高和径流量的增加有利于陆架区微微型浮游植物类群丰度的增加。 相似文献
993.
近年轴流转桨式机组水电站进水口事故闸门有两种布置方式,一门一机布置和多门一机布置.本文结合轴流转桨式机组特性,阐述防止机组飞逸的保护措施.然后通过两种布置方式的优缺点比较,建议采用一门一机的方式. 相似文献
994.
随着城乡建设和市、区经济发展进程不断加快,莱芜市用地矛盾十分尖锐,仍然有粗放利用、破坏浪费土地资源的现象,特别是部分经营者圈而不用,造成土地的闲置浪费。总结了莱芜市国土资源局市区分局在节约集约用地方面取得的成效,分析了存在的问题,并提出了合理化建议。 相似文献
995.
Fang‐Yue WANG Cong‐Ying LI Ming‐Xing LING Hong ZHANG Ya‐Li SUN Weidong SUN 《Resource Geology》2011,61(4):414-423
Xihuashan tungsten deposit is one of the earliest explored tungsten deposits in southeastern China. It is a vein type deposit genetically associated with the Xihuashan granite pluton. Here we report new dating and zircon geochemistry results. Re–Os isotopic dating for molybdenite intergrowth with wolframite in the oldest generation of the Xihuashan pluton yielded an isochron age of 157.0 ± 2.5 Ma (2σ). Zircon U–Pb laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) dating shows that the pluton crystallized at 155.7 ± 2.2 Ma (2σ). This age is similar to the molybdenite Re–Os age for the ore deposit within error. This, together with published data, suggests that the major W(Mo)‐Sn mineralization occurred between 160–150 Ma in southeastern China. These deposits constitute a major part of the magmatic‐metallogenic belt of eastern Nanlin. The lower Re content in molybdenite of the Xihuashan tungsten deposit shows crustal origin for the ore‐forming material. The limited direct contributions from the subducting slab for the tungsten mineralization in the Nanling region suggest a change of the style of the paleo‐Pacific plate beneath southeastern China. 相似文献
996.
矿床水文地质勘查类型划分是进行矿床水文地质勘查重要环节,是做好和优化勘查设计的主要依据。根据我国煤炭矿山经过几十年的开采,特别是近十几年来大规模开采,煤矿水文地质条件发生了较大变化,现行规范划分方案在实际应用中不基础上,结合《煤矿防治水规定》,提出了矿床水文地质勘查类型划分的新方案:类分孔隙充水矿床、裂隙充水矿床、岩溶充水矿床、老空水充水矿床、地表水充水矿床和复合式充水矿床6个;亚类分顶板充水、底板充分水、周边充水和组合式充水4个;型分水文地质条件简单、中等、复杂和极复杂4个。 相似文献
997.
近年来,国有地勘单位在改革发展中,人力资源管理方面普遍存在职工观念滞后、冗员较多、员工积极性不高、人才流失等问题。以总局管理下的某地勘单位为例,对国有地勘单位人力资源现状及存在的主要问题进行了梳理,总结提出了在当前环境下加强人力资源管理的对策及建议:强化人力资源管理意识,营造适宜人才发展的良好氛围;完善用人机制,加大人力资本投入;实施人力资源综合发展战略,设计合理的人才培训计划;深入体制改革,激发员工创新的积极性。 相似文献
998.
Polycyclic aromatic hydrocarbon concentrations in urban soils representing different land use categories in Shanghai 总被引:2,自引:0,他引:2
Jing Liang Guangjun Ma Hailan Fang Ling Chen Peter Christie 《Environmental Earth Sciences》2011,62(1):33-42
An extensive soil survey was carried out in Shanghai to investigate the spatial distribution and possible sources of polycyclic
aromatic hydrocarbons (PAHs) in urban soils. Soil samples were collected from highways, iron-smelting plants, steel-smelting
plants, shipbuilding yards, coking plants, power plants, chemical plants, urban parks, university campuses and residential
areas and were analyzed for 16 PAHs by gas chromatography with mass detection. High PAH concentrations were found in all locations
investigated, with mean values of soil total PAH concentrations in the range 3,279–38,868 μg/kg DM, and the PAH concentrations
were significantly influenced by soil organic matter content. Soil PAH profiles in all districts were dominated by PAHs with
4–6 rings. Principal components analysis and diagnostic ratios of PAHs indicate that they were mainly derived from coal combustion
and petroleum but in soils from highways the PAHs were derived largely from vehicle exhaust emissions. The high concentrations
of PAHs found indicate that many urban soils in Shanghai represent a potential hazard to public health. 相似文献
999.
Guor-Cheng Fang Chaur-Tsuen Lo Winn-Jung Huang Jyh-Cherng Chen Yuh-Shen Wu Jun-Han Huang Yi-Liang Huang 《Environmental Earth Sciences》2011,64(5):1237-1247
The main purpose of this study was to monitor ambient air particles and particulate-bound mercury Hg(p) in total suspended
particulates (TSP) concentration, dry deposition at five characteristic-sampling sites. In addition, the calculated/measured
dry deposition flux ratios of ambient air particles and particulate-bound mercury Hg(p) using three dry deposition models
during the years of 2009–2010 were also studied. The results showed that the order of seasonal variations for mean particulate-bound
mercury Hg(p) concentrations in TSP at Bei-shi (suburban/coastal), Chang-hua (downtown) and He-mei (residential) were all
shown as spring > fall, winter > summer, respectively. However, the order of seasonal variations mean particulate-bound mercury
Hg(p) concentrations in TSP that occurred at Gao-mei (wetland) were shown as spring > fall > winter > summer, respectively.
Finally, the results of this study also indicated that using the Noll and Fang model exhibited batten prediction results for
ambient air particles and particulate-bound mercury Hg(p) dry deposition when compared with the other depositions models at
any of the characteristic-sampling sites for this study. 相似文献
1000.
Duan Lin XiuQin LiHongDa Fang YanHong DongZhuoXuan Huang JiaHui Chen 《Estuarine, Coastal and Shelf Science》2011
To study the relationships between species distribution and environmental variables, calanoid copepods were classified and enumerated, and environmental variables were analyzed along 91 sites of the Pearl River Estuary (China) and adjacent waters. The 91 sites were divided into 3 groups based on surface salinity: the Inner area had salinity level below 10‰ and was mostly located in the Pearl River Estuary, the Coastal area had salinity between 10‰ and 32‰ and was almost located along the coastline, while the Offshore area had salinity level higher than 32‰ and was mainly located in the open area. Indicator Species Analysis was conducted to identify the indicator species within each group from among all calanoid copepods taxa. We found that the Inner area was characterized by Acartiella sinensis, Pseudodiaptomus poplesia and Pseudodiaptomus inopinus, the coastal area was characterized by Temora turbinata and Subeucalanus subcrassus, and the Offshore area was characterized by Paracandacia truncata, Subeucalanus subtenuis, Euchaeta rimana, Pareucalanus attenuatus, Rhincalanus cornutus, Cosmocalanus darwini, Centropages gracilis, Undinula vulgaris, Nannocalanus minor and Paraeuchaeta russelli. Canonical Correspondence Analysis (CCA) was used to identify relevant biotic and abiotic parameters that can best explain the distribution of calanoid copepods. CCA showed that during the summer of 2006, salinity, nutrient variables, especially SiO3–Si, NO3–N and DTN, Depth and Chl a were the environmental variables that strongly impacted the distribution and community structure of calanoid copepods. 相似文献