内蒙古正镶白旗地区侏罗纪含煤地层

内蒙古自治区正镶白旗宝立根陶海一带,在新生界之下赋存有含煤地层。前人将其确定为下白垩统巴彦花组,并以不整合关系置于上侏罗统张家口组之上。本文利用最新钻探和地震资料,从孢粉化石组合、地层层序、含煤地层岩性和地震剖面波组特征等方面综合分析后,认为这套含煤地层位于张家口组之下,层位与大兴安岭中—南部地区的红旗组、万宝组,二连地区的阿拉坦合力群以及冀北的下花园组相当,时代应为早—中侏罗世。     

黄土中宇宙成因核素10Be示踪古地磁场变化研究进展

宇宙成因核素10Be示踪古地磁场的研究在海洋和冰芯研究中得到了广泛应用,然而受黄土来源及沉降过程的复杂性制约,运用中国黄土10Be示踪古地磁场变化的研究直到近年来才取得突破进展.综述了黄土10Be的研究现状并指出将其应用于地磁场示踪研究存在的关键问题,重点介绍了为分离黄土10Be浓度记录所包含的气候因素和地磁场影响因素而建立的LGM分离方法、剩磁矫顽力估算模型方法和"平均值概念"方法.各种创新数理方法的建立基本解决了黄土10Be示踪古地磁场的科学难题,使黄土10Be示踪古地磁场变化研究成为可能.     

鄂尔多斯盆地元古界长城系沉积特征及天然气成藏潜力

长城系是鄂尔多斯盆地太古界—古元古界统一的结晶基底形成后所发育的最早期的沉积盖层,主要形成于区域拉张的裂陷构造背景下,在盆地内部发育多个东北向延伸的次级裂陷槽,并伴随有同构造期的基性岩浆活动。综合分析认为,长城系主要发育海相陆源碎屑建造,而在充填深海、半深海—海湾沉积的裂陷槽区,可能发育有效的海相烃源层;长城系沉积后,盆地大部分地区处于长达9～10亿年的抬升剥蚀环境,利于在其顶部形成大面积分布的风化壳储层;对长城系埋藏史分析表明其具有跨越大构造期而晚期成藏的热演化史,并未发生区域变质而遭破坏,在盆地本部地区具有有利的成藏构造保存条件;深层长城系是下一步天然气勘探值得期待的潜在层系,而勘探的关键是针对盆地本部的次级裂陷槽部署探井以确证长城系烃源岩的有效性。     

路堑高边坡稳定性分析方法和工程实践

探讨了高速公路路堑高边坡的实用工程分类方法,重点分析了岩质高边坡的破坏模式、稳定性分析方法、附加荷载的考虑方法、计算指标的选取方法等问题,结合多年来高边坡设计工作中的经验,探讨了高边坡的设计方法和工程对策。     

北京中关村高新技术企业的集聚与扩散

本文在调查研究的基础上，对北京中关村新技术集聚区域的企业衍生，集聚与扩散因素，以及企业的异地发展和地区内的商业区化趋势进行了讨论。结论指出，中关村新技术集聚体是我国高新技术产业的重要措施，国家对高新技术企业必须进行及时的有效支持和引导，使之获得健康的持续发展。     

基于深地震测深的深部动力学研究方法和应用

深地震测深是探测壳幔岩石圈精细速度结构、探讨岩石圈变形和演化过程的一种有效方法,在青藏高原隆升、克拉通裂解等大陆动力学研究中已发挥了重要的作用.然而,地震测深方法与深部动力学研究的结合尚处于现象描述为主的状态.因此,本文对前人利用深地震测深资料进行深部动力学研究的相关方法进行了回顾与总结:宽角反射/折射地震震相特征具有...     

Atmospheric wet and dry deposition of dissolved inorganic nitrogen to the South China Sea

At the global scale,atmospheric inputs of nitrogen are an important source of the new nitrogen that supports new marine production,especially in oligotrophic open oceans and marginal seas.This study reports quantities of atmospheric deposition of dissolved inorganic nitrogen(DIN) to the largest marginal sea in the North Pacific(the oligotrophic South China Sea,SCS) based primarily on rainwater sampling in the open northwestern region(Yongxing Island) from 2013 to 2015,and aerosol sampling from the SCS basin in June 2017.Atmospheric wet and dry deposition of DIN and their potential contributions to productivity were estimated.The volume-weighted mean rainwater concentrations during the wet and dry seasons were 4.9 and 18.1 μmol L~(-1) for N+N(NO_3~-+NO_2~-),and 5.7 and 4.0μmol L~(-1) for NH_4~+,respectively.Rainwater concentrations of DIN were lower in the marginal seas than in the open ocean.The aerosol NO_3~-concentration was 1.15±1.18 μg m~(-3) during the wet season,which is slightly lower than reported for the East China Sea and East Sea,but higher than in the Arabian Sea.Monthly wet and dry deposition rates ranged from 0.4-3.9 and 0.4-1.2 mmol m~(-2) mon~(-1) for NO_3~-,and 0.2-1.3 and 0.01-0.02 mmol m~(-2) mon~(-1) for NH_4~+,respectively.The annual wet and dry deposition fluxes of DIN were estimated to be 16.8 and 10.1 mmol m~(-2)yr~(-1),respectively.Compared to other marginal seas,the SCS receives less atmospheric NO_3~-inputs than the Yellow Sea,East China Sea,East Sea,and northeastern Mediterranean Sea.The total atmospheric DIN deposition may account for 1.8-11.1% of the nitrogen supporting new production and 0.7-1.8% of the nitrogen supporting primary production.     

Algal community and pollution indicators for the assessment of water quality of Ismailia canal,Egypt

Stochastic Environmental Research and Risk Assessment - The phytoplankton community structure is affected by both ecological and spatial factors. Influences of these two factors on phytoplankton...     

The unusual 2014–2016 El Ni?o events: Dynamics,prediction and enlightenments

The 2014–2016 El Ni?o events consist of a stalled El Ni?o event in the winter of 2014/2015 and a following extreme El Ni?o event in the end of 2015. Neither event was successfully predicted in operational prediction models. Because of the unusual evolutions of these events that rarely happened in the historical observations, few experience was ready for understanding and predicting the two El Ni?o events when they occurred. Also due to their specialties, considerable attention were attracted with aims to reveal the hidden mechanisms. This article reviews the recent progresses and knowledge that were obtained in these studies. Emerging from these studies, it was argued that the key factor that was responsible for the stalled El Ni?o in 2014 was the unexpected summertime Easterly Wind Surges(EWSs) or the lack of summertime Westerly Wind Bursts(WWBs). Most operational prediction models failed to reproduce such stochastic winds and thus made unrealistic forecasts. The two El Ni?o events awakened the research community again to incorporate the state-of-the-art climate models to simulate the stochastic winds and investigate their roles in the development of El Ni?o.