Chemical kinetics study of hydrocarbon regeneration from organic matter in carbonate source rocks and its significance     

LU ShuangFang  ZHONG NingNing  XUE HaiTao  PAN ChangChun  LI JiJun & LI HongTao Daqing Petroleum Institute  Daqing  China  China University of Petroleum  Beijing  China  Guangzhou Institute of Geochemistry  Chinese Academy of Sciences  Guangzhou  China 《中国科学D辑(英文版)》2007,50(4):536-543

In the comparison research of hydrocarbon regeneration, a low maturity carbonate source rock is heated to different temperatures in a gold tube to obtain a series of samples with different maturities. Then, the heated samples, before and after extraction, are subjected to Rock-Eval pyrolysis through a thermal simulation of hydrocarbon regeneration in order to inspect pyrolysis characteristics and probe into the characteristics of the chemical kinetics of each sample. The results indicate that, whether hy- drocarbon regeneration peak is delayed or advanced, the potential of hydrocarbon regeneration is closely related to the expulsion amount and breakdown maturity of primary hydrocarbon generation. After extraction, the average activation energy of artificially maturated samples increases with the in- creasing maturity, but the chemical kinetic properties of un-extracted samples decrease. The calibrated chemical kinetic models that describe extracted and un-extracted samples are applied to the Bohai Bay and the Songliao Basin, and the results indicate that the combination of the two models can explain some contradictory conclusions previously reported. These results also facilitate the quantitative evaluation of the amount of hydrocarbon regeneration by the chemical kinetic method.  相似文献   

沙坡头地区人工植被油蒿种群结构与更新的研究   总被引：7，自引：7，他引：7  

马凤云  李新荣  龙利群  张景光 《中国沙漠》2002,22(6):571-575

采用野外调查和比较分析的方法,对沙坡头地区人工植被油蒿种群的结构和更新进行了研究.通过对不同固沙起始年代油蒿种群大小结构的分析发现,幼树个体的数量较多,中等大小的成年个体数量少,老龄个体的数量极少.年限较短的人工植被区油蒿幼树个体的数量多于年限较长的人工植被区,而油蒿幼苗的数量则呈相反的趋势.油蒿幼苗在不同的地形中分布数量也不同,丘间地有较多的幼苗,背风坡幼苗特别少.油蒿成年个体在人工植被区中呈均匀分布,油蒿幼苗则呈聚集分布.  相似文献   

四川喇叭河自然保护区珙桐群落特征与更新   总被引：4，自引：0，他引：4  

王海明  李贤伟  陈治谏  王海娥  徐云  高建武  杜占青 《山地学报》2005,23(3):360-366

在对四川喇叭河自然保护区珙桐群落进行生态学调查的基础上，着重分析了该区珙桐群落植物的物种构成、群落结构、重要值排序、simpson指数、Shannon-Wiener指数，以及珙桐群落的生境条件、更新动态等。研究结果表明：(1)喇叭河自然保护区珙桐群落是一种典型的中亚热带中山山地常绿、落叶阔叶混交林植被；适宜分布于温暖、潮湿、雨量充沛、云雾多、日照少、山陡沟深的地段；(2)珙桐群落植物种类丰富、古老、特有性强；(3)珙桐群落垂直结构明显，珙桐构成建群种；草本层发达；(4)该地区珙桐以有性和无性繁殖更新，但有性繁殖能力很低，以无性繁殖更新为主，群落在其分布区内是一种稳定存在的群落类型。  相似文献   

新疆干旱区天然植被最低生态耗水量概念分析     

杨海梅  李明思  彭玉刚 《干旱区地理》2005,28(6):770-774

干旱区天然植被的最低生态耗水量问题关系到该地区生态建设的标准问题，也是评价水资源生态承载力所必须考虑的指标。同时，天然植被的最低生态耗水量是制定绿洲农业用水和节水规划的依据之一。据不同的生态目标分析并提出了天然植被不同的最低生态耗水量的概念，指出植物的最低生态耗水量是最低生态效应下的植物的耗水量，而且不同生态区要求的生态效应不同，因此，植物在不同生态目标下会表现出的最低生态耗水量不同。进行天然植被最低生态耗水量评价时，首先要明确生态目标。另外，通过试验发现，天然植被存在着生态耗水效率的概念，水分的生态效应存在最优值。  相似文献   

Rainfall-driven Episodic Flood Events: are they a major factor in moulding New South Wales arid land vegetation patterns?     

Martin E. Westbrooke 《The Australian geographer》2005,36(2):171-181

Episodic high rainfall has been proposed as an important factor in perennial species recruitment but flooding based on rainfall at a distance from the site has received little attention. Although such flood events in arid Australia are rare, studies of the ephemeral Olary Creek indicate that occasional floods can also have a high impact on the vegetation and landscape. During February 1997, a high-rainfall event caused flooding in the Olary Creek. One branch of the creek created a terminal lake within mallee vegetation on Nagaela Station in far-western New South Wales. The flood path of Olary Creek and this terminal lake allow study of the importance of rainfall-driven flood events in shaping vegetation in arid environments. This paper reports (i) the response of arid land plant species to high-rainfall-driven episodic flood events and (ii) how grazing pressure from native and introduced herbivores can impact on native species response.

A systematic study was conducted to understand the botanical composition in flooded and control areas based on 25 m² fenced and unfenced plots subjected to flooding and non-flooding. For 6 years following flooding, species richness in the flooded area was twice that of unflooded areas. In particular, 27 native species from 13 families were recorded both in the enclosed and open plots located in the flooded area. Over the study period nine species: Brachyscome ciliaris, Helichrysum leucopsidium, Vittadinia cuneata, Casuarina pauper, Maireana sedifolia, Salsola kali, Sclerolaena obliquicuspis, Eremophila sturtii and Eucalyptus foecunda germinated only in the flooded enclosed plots. Further, 11 exotic species from five families were recorded in the flooded (both enclosed and open) plots over the study period. Knowledge gained from this study will contribute to management strategies for arid land vegetation.  相似文献   

Assessing the discourses and practices of urban regeneration in a growing region     

Mike Raco 《Geoforum》2003,34(1):37-55

Most research on the discourses and practices of urban regeneration in the UK has examined case studies located in areas of relative socio-economic distress. Less research has been undertaken on regeneration projects and agendas in areas characterised by strong economic growth. Yet, it is in such places that some of the best examples of the discourses, practices and impacts of contemporary urban regeneration can be found. In some areas of high demand regeneration projects have used inner urban brownfield sites as locations for new investment. With the New Labour government’s urban policy agendas targeting similar forms of regeneration, an examination of completed or on-going schemes is timely and relevant to debates over the direction that policy should take. This paper, drawing on a study of urban regeneration in one of England’s fastest growing towns, Reading in Berkshire, examines the discourses, practices and impacts of redevelopment schemes during the 1990s and 2000s. Reading’s experiences have received national attention and have been hailed as a model for other urban areas to follow. The research documents the discursive and concrete aspects of local regeneration and examines the ways in which specific priorities and defined problems have come to dominate agendas. Collectively, the study argues that market-driven objectives come to dominate regeneration agendas, even in areas of strong demand where development agencies wield a relatively high degree of influence. Such regeneration plays a symbolic and practical role in creating new forms of exclusion and interpretations of place.  相似文献   

Cultural policy and place promotion: Swansea and Dylan Thomas     

Helen Watkins  David Herbert 《Geoforum》2003,34(2):249-266

As former industrial cities have experienced radical changes to the bases of their economies, the imperatives of finding new roles and functions has often led to the adoption of cultural policies. These are diverse and partial but have become part of place promotion policies designed to attract visitors and investors. The connection with a literary figure offers one exploitable quality and this paper explores the adoption of Dylan Thomas, poet and writer, as an icon for Swansea. What emerges is the existence of a diversity of interested individuals and groups, who start from different positions but work towards a common goal. The tensions about the life and works of the poet, evident over the 50 years since his death are still there but the key players, including the City and County of Swansea, are finding ways of reconciling their differences in the ‘production’ of Dylan Thomas. This use of a writer and his local connections forms part of the more general process of making a cultural policy for the city.  相似文献   

南京大都市空间演化与地域结构发展策略   总被引：1，自引：0，他引：1  

姚士谋  顾朝林 《地理与地理信息科学》2001,17(3):7-11

随着全球经济一体化、信息化时代的到来 ,各国各地区的城市发展策略亦受到深刻的影响。南京位于亚太地区我国沿海中部 ,具有江海优势 ,国务院在 90年代中期批复的南京市总体规划正在实施 ,有力地促进了南京城市的空间扩展及其城市内部空间结构深刻的变化。该文就南京都市圈内部城市空间结构的特征扩展模式及其发展趋势、策略作一个多层面的论证 ,从城市设计与规划艺术手法的高度作综合评述 ,为南京大都市的空间合理发展提供科学依据。  相似文献   

长石莼（缘管浒苔）（Ulva linza）原生质体再生与分化发育初步研究          下载免费PDF全文

陈群芳  汤文仲  冯子慧  霍元子  何培民 《海洋与湖沼》2011,42(3):397-403

采用细胞酶解技术获得长石莼（缘管浒苔）原生质体,再通过细胞培养观察原生质体再生以及各种分化发育途径。结果表明,长石莼（缘管浒苔）主要存在3种分化发育途径：1）部分原生质体可直接分裂形成有假根或无假根得单细胞苗。2）部分原生质体分裂成规则细胞团或不规则细胞团,最后形成苗簇。3）部分原生质体可发育为孢子囊／配子囊,其中部分...  相似文献   

Patterns and Cellular Mechanisms of Arm Regeneration in Adult Starfish Asterias rollestoni Bell     

FAN Tingjun  FAN Xianyuan  DU Yutang  SUN Wenjie  ZHANG Shaofeng  LI Jiaxin 《青岛海洋大学学报(英文版)》2011,(3):255-262

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