The Radcliffe Wave Parameters from Data on Open Star Clusters     

V.V.Bobylev  A.T.Bajkova 《天文和天体物理学研究(英文版)》2024,(3):108-111

A spectral analysis of the vertical positions and velocities of 374 open star clusters (OSCs) was carried out.We took these OSCs from the Hunt and Reffert catalog;they have an average age of about 10 million years,and are located on the galactic plane XY in a narrow zone inclined by 25°to the galactic axis Y.The following estimates of the parameters of the Radcliffe wave were obtained:(a) the maximum value in periodic perturbations of vertical coordinates Z_max=92±10pc with the wavelen...  相似文献   

Heavy metal stress induced hyperglycemia in blue swimmer crab, Portunus pelagicus     

SARAVANAN R.  SUGUMAR V.  BEEMA MAHIN M. I. 《海洋学报(英文版)》2018,37(5):47-53

The study was to find out the effect of cadmium and mercury on levels of hemolymph glucose, crustacean hyperglycemic hormone (CHH) and hepatopancreas glycogen in the blue swimmer crab Portunus pelagicus. The experiments were performed in both intact and eyestalk ablated crabs. Quantification of CHH was done by the indirect ELISA with the aid of primary anti-Carcinus maenas-CHH antibody. Higher glucose concentration was observed on exposure to 8×10^-6 of cadmium ((825.6±5.42) μg/mL) and 6×10^-6 of mercury ((90.5±6.25) μg/mL) after 48 h and 24 h respectively. Higher level of hemolymph glucose was observed in eyestalk intact crabs on exposure to cadmium and mercury than eyestalk ablated crabs. Decrease in the levels of CHH was observed in both eyestalk intact and ablated crabs on heavy metal exposure. Decline of the hepatopancreas glycogen level was also witnessed with the exposure to heavy metal, which validated its utilization in the production of glucose. Thus this study brings to light, the variations in hemolymph glucose, CHH and hepatopancreas glycogen on heavy metal stress. These carbohydrate metabolites can be used as biomarkers in assessing heavy metal contamination in water bodies.  相似文献   

一次行星际磁场南向突变的高纬电离层对流响应特征   总被引：1，自引：0，他引：1       下载免费PDF全文

徐良  徐继生  A.V.Koustov 《地球物理学报》2007,50(6):1623-1631

本文利用北半球的超级双极光雷达网数据,考察了一次行星际磁场南向突变时高纬电离层对流的响应特征,着重分析了响应的时间尺度. 对所研究的事件,行星际磁场南北分量在1.5 min内从+7 nT突变到-8 nT,而在突变前后约40 min内都保持相对稳定. 结果表明,电离层对流的初始响应发生在磁正午附近,相对于行星际磁场突变到达磁层顶的时间有大约3 min的滞后;响应与磁地方时有明显依赖关系,离磁正午越远,响应的滞后时间越长,晨昏两侧的对流响应比磁正午滞后约6 min,磁午夜的对流响应比磁正午滞后约12 min;对流重新趋于稳定的时间与磁地方时没有明显的依赖关系,该时间尺度约为10～14 min.  相似文献   

地球的工程地质结构——内容、成因、判别标志及空间分布     

V.T.Trofimov 《地学前缘》2007,14(2):257-267

文中定义了“工程地质结构”这一术语,讨论了其内容、成因、判别标志与依据、谱系分类及全球实际系列,并对全球及各大洲的超巨型、巨型、大型、中型工程地质结构的分布规律进行了描述。  相似文献   

Using thermal remote sensing in the classification of mountain permafrost landscapes     

Svetlana V.KALINICHEVA  Alyona A.SHESTAKOVA 《山地科学学报》2021,(3):635-645

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Gold and tin of fluid-magmatic systems:causes of combination-separation of concentration elements     

I.I. Fatyanov  V.G. Khomich 《东北亚地学研究》2009,(3)

The aim of the investigation is to reveal possible causes of isolation and co-occurrence of the economically significant concentrations of gold and tin. Comparative analysis of the different-rank factors that influenced migration and concentration of these elements show that different geochemical properties of Au and Sn are responsible for isolation of their big concentrations giving rise to independent metallogenic provinces, zones, and ore nodes. These differences resulted in individualization of the elem...  相似文献   

Lithostructural controls in Douala-Buea Region landscape(SW Cameroon margin): Insights from morphometric analysis     

Christian BALLA ATEBA  Sébastien OWONA  Moussa NSANGOU NGAPNA  Véronique MANGA TSIMI  DieudonnéMINYEM  Joseph MVONDO ONDOA 《山地科学学报》2021,(1):68-87

The Douala-Buea Region(DBR;4°-5°N,9°-10°30’E),a portion of the southern Cameroon passive margin,developed on the Proterozoic granito-gneissic basement and the Cretaceous to Recent volcanosedimentary cover,was explored in order to evaluate the lithology and tectonics controls on its landscape usingthequalitativeandquantitative geomorphological analyses based on 30 m resolution Digital Elevation Models(DEM)and field evidences.This area displays an uneven and complex landscape differentiated into four morphological units:Douala,Nkondjock,Kumba and Buea Units.The Douala Unit corresponds to the Coastal Plain and is extended on the Douala-Kribi/Camposedimentarybasin.The Nkondjock Unit represents a middle plateau developed on a Proterozoic granito-gneissic basement.The Kumba Unit matches with the southernmost volcanic Western Cameroon High Plateau.The Buea Unit corresponds to the Mount Cameroon stratovolcano.The relief analysis through mountain-front sinuosity(Smf,1.19–1.43)and relative relief ratio(Rr,0.10–2.31)vary from one unit to another.The drainage network analysis including drainage patterns,stepped longitudinalriverprofiles,theassociated morphometric indexes,notably the concavity index(IC,0.56–0.88),deviation(D,267–2912 m),basin asymmetry factor(A_F,6.37–42.12),hypsometric integral(HI,0.10–0.29),valley floor width to valley height ratio(V_f,0.36–2.75),elongation ratio(R_e,0.30–0.50),watershed slope(S,6.88–88.88)and stream length gradient index(SL,0–3332)vary from one basin to another too.These results also show the heterogeneous and uneven DBR landscape controlled by its lithology and active tectonics.The drainage system reveals concave to concavo-convex longitudinal river profile shapes with knick points,asymmetric basins,and fault reactivations,and highlights the tectonics activity that used to occur through the time and their control on the morphology.Together,they document the lithostructural controls on the DBR landscape evolution,extendable in the whole SW Cameroon margin.  相似文献   

The Representation of Soil Moisture-Atmosphere Feedbacks across the Tibetan Plateau in CMIP6     

Joshua TALIB  Omar V.MüLLER  Emma J.BARTON  Christopher M.TAYLOR  Pier Luigi VIDALE 《大气科学进展》2023,(11):2063-2081

Thermal processes on the Tibetan Plateau(TP) influence atmospheric conditions on regional and global scales. Given this, previous work has shown that soil moisture-driven surface flux variations feed back onto the atmosphere. Whilst soil moisture is a source of atmospheric predictability, no study has evaluated soil moisture-atmosphere coupling on the TP in general circulation models(GCMs). In this study, we use several analysis techniques to assess soil moisture-atmosphere coupling in CMIP6 sim...  相似文献   

超临界水氧化技术   总被引：4，自引：0，他引：4       下载免费PDF全文

李武  V.M.Valyashko  高世扬 《盐湖研究》1999,7(1):35-38

当水的温度为３７４．２℃．压力为２２１×１０５Ｐａ时,它变成一种即非液体又非气体的流体,该点称为水的临界点,温度和压力高于此点的水作为超临界水,超临界水有许多与普通水截然不同的性质,由此导致了超临界水的多种用途。ＳＣＷＯ（超临界水氧化）即是其中之一。  相似文献   

东亚地区地磁场的理论分析与矩谐模型   总被引：7，自引：2，他引：5       下载免费PDF全文

王月华  安振昌  V.P.Golovkov  N.M.Rotanova  A.L.Kharitonov 《地球物理学报》1999,42(5):640-647

根据东亚地磁场三分量绝对测量资料,使用矩谐分析方法研究了东亚地区（北纬２０-７０,东径４０-１６０）的地磁异常场,计算出地磁异常的矩谐模型．据此模型编绘了Ｘ．ＹＺ三分量磁异常图．结果表明,在东亚的中心地区地磁异常的分布比较均匀,表现出区域特征．而在边界地区,特别是西南角和东南角一带,由于缺乏实测数据,边界效应很大．  相似文献