河外H2O超脉泽源及与其相关的分子谱线的观测和研究

自从在活动星系核NGC4945的视线方向上发现第一个河外H2O超脉泽源以来，迄今为止已发现了19个河外H2O超脉泽源，对与活动星系核成协和河外H2O超脉泽源及分子谱线的观测和研究是探测和研究活动星系核核区中央源，拱核气体和尘埃环性质的非常有效的工具，主要评述对河外H2O超脉泽源及与其相关分子谱线的搜索，观测和理论研究现状。     

徐州土壤多环芳烃的环境地球化学迁移特征

选择江苏徐州黄棕壤进行不同深度层位多环芳烃含量的定量分析,研究并探讨了多环芳烃在土壤深度剖面中的地球化学迁移特征。研究结果显示,多环芳烃在徐州土壤剖面中主要集中在地表0~20 cm内。其中低环多环芳烃化合物的迁移能力较强,4~6环等高环化合物相对较难迁移,主要残留于地表生态系统环境中。     

对松辽盆地钱家店凹陷铀成矿作用的重新认认识

钱家店凹陷中的含矿层位主要为上白垩统姚家组,前人认为其中的红色砂岩为原生成因,但大量的证据证实砂岩原生应以灰色为主,红色砂岩为后生氧化蚀变造成,并控制着钱家店铀矿床铀矿化的产出.在此基础上建立该矿床的后生蚀变分带,依次为红色蚀变带、黄色蚀变带、灰白色蚀变带、过渡带、原生带,红色蚀变带为主要的氧化带,铀矿化主要集中在过渡带.平面上铀矿化主要分布于层间氧化带前锋线附近的位置,并在氧化舌状体的前端和两个氧化舌状体之间存在铀的富集.文章最后还建立了该矿床的成矿模式,并对区域上层间氧化带的展布进行了讨论.     

祁连山七一冰川流域各类环境介质中多环芳烃的分布特征与来源研究

从祁连山七一冰川流域各介质中总共检测出2～7环的多环芳烃50多种,其中16种美国EPA优控物质中,只有二氢苊和二苯并[a,h]蒽没有被检测到.雪冰和冰川融水样品中相对富集3环和4环,雪冰不溶微粒和冰尘以及七一冰川周围表层土壤样品主要以4～6环为主,这是由PAHs自身的物理化学性质决定的.荧蒽/芘,菲/蒽比值表明,研究区检测出来的多环芳烃可能主要来自于化石燃料的高温燃烧,特别是煤的燃烧和机车尾气排放产生.大气污染传输与干湿沉降是七一冰川及其周围土壤中PAHs的主要输入途径.     

南水北调西四环暗涵工程穿越桥梁监控量测技术应用

南水北调西四环暗涵工程为京石段控制性工程,下穿北京市西四环路桥梁30余座,桥梁的安全至关重要。在暗涵施工过程中对桥梁实施了有效的监控量测技术,通过自动化监测和常规监测手段获取数据,然后对监测数据进行详细分析、对比,以研究暗涵下穿桥梁施工过程中桥梁的受力变形协调过程。结果表明:墩柱差异沉降小于允许沉降的80%;墩柱倾斜值小于允许值的30%。监控工作做到了过程预警、过程控制,规避了工程风险,对类似工程具有借鉴意义。     

饱和粉砂不稳定性的试验研究

通过对净砂和级配良好粉砂(含10 %粉土)进行一系列三轴固结不排水试验（CU）,研究了粉土、孔隙比和围压对饱和粉砂不稳定性的影响。试验结果表明,净砂与粉砂在不排水剪切条件下均会出现应变软化现象（即不稳定性）。同一围压下脆性指数(IB)随孔隙比增加,但不稳定线的应力比随孔隙比增加而减小。引用等效粒间孔隙比(ege)后,净砂和粉砂在ege-ln p?平面上拥有基本相同的临界状态线。在临界状态理论及等效粒间孔隙比的基础上,提出在同一修正状态参数(?ge)下净砂和级配良好粉砂有相似的不稳定性。     

1998年春深圳湾环节环沟藻赤潮及其发生原因的探讨

1998年4月23日至29日深圳湾发生了较大规模的环节环沟藻赤潮,面积逾200km2,细胞密度高达3.8×106 个/L。赤潮发生于大量降雨之后 ,高峰期水体盐度在20以下。在深圳河河口海域 ,虽然富营养化程度也较高 ,但由于悬浮物含量过高 ,浮游植物及环节环沟藻数量较少。赤潮期间 ,深圳湾没有发生死鱼现象 ,养殖牡蛎的大量死亡估计与赤潮无关     

Photoinduced toxicity single and binary mixtures of four polycyclic aromatic hydrocarbons to the marine diatom Skeletonema costatum

Diatom Skeletonema costatum Cleve is one of the main predominant phytoplankton species in the Changjiang Estuary in China. In order to provide some basic information for future assessment of the potential risk on phytoplankton communities in this estuary caused by polycyclic aromatic hydrocarbons(PAHs), this alga was selected as a representative to investigate the photoinduced toxicity of PAHs, in single and mixture. Four PAHs including three-ring phenanthrene and anthracene, four-ring fluoranthene and pyrene were tested in the laboratory. The single toxicity of each PAH on this microalga was compared with and without the simulated solar UV radiation. The results showed that this microalga was sensitive to PAH's photoinduced toxicity. Ratios of the 72 h median effect concentration obtained for fluorescent and UV light tests were about 8.4 for phenanthrene, 13.0 for anthracene, 6.5 for fluoranthene, and 5.7 for pyrene, indicating that UV light enhanced the PAH toxicity to this alga significantly. Under the fluorescent radiation (lacking UV), the dose-response curves based on chemical concentrations revealed that the order of toxic strength was fluoranthene greater than pyrene greater than anthracene greater than phenanthrene; while under the UV radiation (476 μW/cm2 for UVA, 6.5 μW/cm2 for UVB) it became fluoranthene approximately equaling anthracene greater than pyrene greater than phenanthrene, indicating that the UV light also changed its relative toxicity to this alga. The photoinduced toxicity of PAHs to the marine diatom S. costatum might be a synergistic effect of photosensitization reactions (e.g., generation of single-state oxygen) and photomodification (photooxidation and/or photolysis).The combined effects of six binary mixtures on the marine diatom S. costatum were investigated using the additive-index method. Four binary-mixtures (phenanthrene plus anthracene; phenanthrene plus pyrene; anthracene plus fluoranthene; anthracene plus pyrene) were found to be synergistic joint action mode, while two binary-mixtures (phenanthrene plus fluoranthene; fluoranthene plus pyrene) displayed antagonist, revealing a complex pattern of possible interactions. The combined action mode of PAHs might be related to various factors such as the mixture compounds, mixture ratios and test conditions, etc.     

Design and Strength Analysis of A Spherical Connector for Lifting Subsystem in Deep Sea Mining System

1 .IntroductionThe lifting systemis composed of pipes andtheir connectors .It is not onlythe lifting channel formanganese nodule betweenthe miningship andintermediate bin,but alsothe supporting massfor deepsea miningequipment and cables .Sothe reliability…