Biomarkers in the Molar Tooth （MT）-Bearing Limestones in the Jilin-Liaoning Area of China   总被引：2，自引：1，他引：2  

旷红伟  李艳霞  曾艳涛  孟祥化  葛铭 《中国地球化学学报》2004,23(4):334-341

The origin of Molar Tooth (MT) carbonates has been argued for more than 100 years, which are a kind of Proterozoic carbonates especially composed of microsparite with ptygmatically folded and sheet-like structures. Biomarkers detected in the microcalcsparite from the Wanlong and Xingmincun formations in the Jilin-Liaoning area showed there are abundant normal alkanes, isoprenoids, hopanes, steranes, alkylmethylcyclohexanes, and alkyleyclohexanes, indicating a diversity of biological source: long-chain isoprenoids, the major components of chlorophyll, such as C19, C20, a kind of major biomarkers synthesized early by isoprenoid monomers; hopanes a type of characteristic biomarkers from prokaryote, such as archaebacteria and cyanobacteria; sterane a biomarker for eukaryote; and two kinds of alkanes with C17, C18 as the main peaks representing aquatic bacteria and with C23, C24 as the main peaks representing fungi, respectively. Biomarker analysis showed that MT is the result of bacterial and algal activities, which is a kind of organisms between aerobic and anaerobic bacteria, reproducing well in normal or slightly saline sea water under weak oxidation-reduction conditions, resulting in rapid deposition of calcite as microsparite clue to some mechanisms.  相似文献   

Seismic performance evaluation of steel arch bridges against major earthquakes. Part 1: dynamic analysis approach     

Tsutomu Usami  Zhihao Lu  Hanbin Ge  Takeshi Kono 《地震工程与结构动力学》2004,33(14):1337-1354

In this study the inelastic behavior of steel arch bridges subjected to strong ground motions from major earthquakes is investigated by dynamic analyses of a typical steel arch bridge using a three‐dimensional (3D) analytical model, since checking seismic performance against severe earthquakes is not usually performed when designing such kinds of bridge. The bridge considered is an upper‐deck steel arch bridge having a reinforced concrete (RC) deck, steel I‐section girders and steel arch ribs. The input ground motions are accelerograms which are modified ground motions based on the records from the 1995 Hyogoken‐Nanbu earthquake. Both the longitudinal and transverse dynamic characteristics of the bridge are studied by investigation of time‐history responses of the main parameters. It is found that seismic responses are small when subjected to the longitudinal excitation, but significantly large under the transverse ground motion due to plasticization formed in some segments such as arch rib ends and side pier bases where axial force levels are very high. Finally, a seismic performance evaluation method based on the response strain index is proposed for such steel bridge structures. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

西藏降水量、气温变化特征及相关关系   总被引：9，自引：2，他引：9       下载免费PDF全文

葛朝霞  王会容  曹丽青  王晓兰 《气象科学》2004,24(4):468-473

本文利用40a逐日降水与气温资料，分析了西藏地区降水量、气温的年变化和年代际变化特征，讨论了气温与降水量的相关关系。结果表明：近几十年来，西藏年平均气温、降水量有明显上升的趋势；气温是影响西藏地区降水量的重要因子之一。绝大多数月份的月平均降水量与前期气温有很好的相关关系，可作为月平均降水量预报的参考依据。  相似文献   

地质雷达快速检测运营公路隧道隐患   总被引：4，自引：0，他引：4  

赵天库  葛为中  张忠良 《上海国土资源》2004,18(3):62-66

为了评价运行多年隧道的衬砌质量，查找隐患，开展了拱顶的地质雷达无损快速检测。在雷达波形剖面图上分析空洞、不密实异常，推断出大量隐患。物探成果经过开凿验证，证明其隐患定位成功率在85％以上。地质雷达快速检测方法为隧道病害治理提供了可靠的基础资料。  相似文献   

基于DOM的宁波市城市用地调查     

葛纪坤 《现代测绘》2004,27(2):38-39

介绍以DOM，进行城市用地调查方式，极大的提高了调查的效率。  相似文献   

利用跨断层形变资料研究天山中段断层现今活动特征     

韩桂红  滕海涛  高歌  李桂荣  张治广 《大地测量与地球动力学》2019,39(1):72-76

利用2001年以来天山中段多个跨断层形变场地的测量资料，从断层运动方向和断层平均速率2个方面分析天山中段3条断层现今活动特征。结果表明，霍玛吐断裂呼图壁段断层的活动性质为正、逆断和左、右旋交替活动；北轮台-辛格尔断裂库尔勒段断层表现为右旋运动特征，活动性质为逆断性；妖魔山F2断裂乌鲁木齐段的断层活动性质以逆断为主。妖魔山F2断裂乌鲁木齐段断层的活动程度最高，霍玛吐断裂呼图壁段最低。霍玛吐断裂、北轮台-辛格尔断裂、妖魔山F2断裂垂直方向上基本均处于张性变化，前两者水平向处于挤压状态；断层活动速率的时间进程具有阶段性特征，各个时间段转折点有较好的匹配性。  相似文献   

Real-time retrieval of precipitable water vapor from GPS and BeiDou observations   总被引：3，自引：2，他引：1  

Cuixian Lu  Xingxing Li  Tobias Nilsson  Tong Ning  Robert Heinkelmann  Maorong Ge  Susanne Glaser  Harald Schuh 《Journal of Geodesy》2015,89(9):843-856

  相似文献   

创意再生视域宁波老工业区绅士化动力机制   总被引：6，自引：1，他引：5  

马仁锋  王腾飞  张文忠 《地理学报》2019,74(4):780-796

绅士化成为全球各类城市更新的核心现象,受地理、城市和规划等学科关注。以宁波和丰创意广场形成为例,运用问卷调查和访谈数据,借助扎根理论和结构方程模型分别构建和验证涵盖空间生产、推拉模式和创意集群孕育在内的老工业区绅士化动力机制。研究发现：① 生成和丰创意广场的创意修复过程呈现典型绅士化现象,且该现象具有高端写字楼主导的开放性和多元景观特征,入园企业私营化、生产要素创意化和生产关系外向化的业态特征以及年轻化、情怀化、创意化和服务化的群体特征;② 和丰绅士化现象是老工业区以推拉方式形成的社会空间置换,权力、资本和创意联结而成的再生产关系主导空间实践;建筑规划师和创意阶层主导的物质性空间营造和创意实践形成空间表征;空间表征推动创意集群内生发展和演化,催化了基于文化、理想和情感体验的文化共识和身份认同,升华为表征性空间,形成了“地方元素的感性认可→资本要素和关系力量的理性约束→地方元素、资本要素和关系力量协同→关系力量的反馈”逻辑路径,激活了老工业区空间演化。③ 和丰创意集群育成取决于文化氛围、办公环境、经济区位、政府政策和社会关系网络等要素相互作用。  相似文献   

Effects of feeding time on complement component C7 expression in Pelteobagrus vachellii subject to bacterial challenge     

Shao  Ting  Qin  Chuanjie  Duan  Huiguo  Yuan  Dengyue  Wen  Zhengyong  Wang  Jun  Ge  Fanglan 《中国海洋湖沼学报》2018,36(6):2358-2367

Journal of Oceanology and Limnology - Shifting the feeding time for fish from daytime to nighttime could alter their digestive behavior, disturb their metabolism, and may affect immune-related...  相似文献   

Nitrogen Budget in Recirculating Aquaculture and Water Exchange Systems for Culturing <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis>     

Zhao Chen  Hongxing Ge  Zhiqiang Chang  Xiefa Song  Fazhen Zhao  Jian Li 《中国海洋大学学报(英文版)》2018,17(4):905-912

In order to investigate the culture characteristics of two indoor intensive Litopenaeus vannamei farming modes, recirculating aquaculture system (RAS) and water exchange system (WES), this study was carried out to analyze the water quality and nitrogen budget including various forms of nitrogen, microorganism and chlorophyll-a. Nitrogen budget was calculated based on feed input, shrimp harvest, water quality and renewal rate, and collection of bottom mud. Input nitrogen retained in shrimp was 23.58% and 19.10% respectively for WES and RAS, and most of nitrogen waste retained in water and bottom mud. In addition, most of nitrogen in the water of WES was TAN (21.32%) and nitrite (15.30%), while in RAS was nitrate (25.97%), which means that more than 76% of ammonia and nitrite were removed. The effect of microalgae in RAS and WES was negligible. However, bacteria played a great role in the culture system considering the highest cultivable cultivable bacterial populations in RAS and WES were 1.03×10¹⁰ cfu mL^?1 and 2.92×10⁹ cfu mL^?1, respectively. Meanwhile the proportion of bacteria in nitrogen budget was 29.61% and 24.61% in RAS and WES, respectively. RAS and WES could realize shrimp high stocking culture with water consuming rate of 1.25 m³ per kg shrimp and 3.89 m³ per kg shrimp, and power consuming rates of 3.60 kw h per kg shrimp and 2.51 kw h per kg shrimp, respectively. This study revealed the aquatic environment and nitrogen budget of intensive shrimp farming in detail, which provided the scientific basis for improving the industrial shrimp farming.  相似文献