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941.
Existing and planned radiotelescopes working in the millimetre (mm) and sub-millimetre wavelengths range provide the possibility to be used for atmospheric line observations. To scrutinize this potential, we outline the differences and similarities in technical equipment and observing techniques between ground-based aeronomy mm-wave radiometers and radiotelescopes. Comprehensive tables summarizing the technical characteristics of existing and future (sub)-mm radiotelescopes are given. The advantages and disadvantages using radiotelescopes for atmospheric line observations are discussed. In view of the importance of exploring the sub-mm and far-infrared wavelengths range for astronomical observations and atmospheric sciences, we present model calculations of the atmospheric transmission for selected telescope sites (DOME-C/Antarctica, ALMA/Chajnantor, JCMT and CSO on Mauna Kea/Hawaii, KOSMA/Swiss Alpes) for frequencies between 0 and 2000 GHz () and typical atmospheric conditions using the forward model MOLIERE (version 5). For the DOME-C site, the transmission over a larger range of up to 10 THz () is calculated in order to demonstrate the quality of an Earth-bound site for mid-IR observations. All results are available on a dedicated webpage. 相似文献
942.
银根—额济纳旗盆地是在前寒武纪结晶地块和古生代褶皱基底基础上发育起来的中新生代断陷型沉积盆地,断陷分割严重,具有小湖盆多物源、相带窄、相变快、冲积体系沉积特点;每个凹陷为一个独立的断陷湖盆,自成一个独立的沉积单元,构成相对独立的含油气系统或勘探单元。侏罗系煤系与白垩系湖相泥质烃源岩发育,有机碳丰度中等,处于成熟与高成熟演化阶段;储集层以侏罗系致密砂岩与白垩系砂砾岩为主,受成份成熟度与结构成熟度所限,储层物性较差,多为低孔低渗储集层类型;由于后期构造改造强烈,成藏保存至关重要。在相对继承性较好的坳陷内主力沉积凹陷有利于油气生成、运聚成藏和后期保存。本文主要采用成因法(盆地模拟),结合地质条件类比法计算盆地石油资源量为6.5×108 t (含非常规致密油),非常规致密砂岩气为1 500×108 m3,具有良好勘探潜力;勘探方向上应立足居延海、查干、苏红图和达古4个主要沉积坳陷中的主力断陷,在加大针对断背斜、断块、断层遮挡的构造油气藏勘探的同时,注重斜坡区与凹陷区非常规致密油、致密砂岩气藏勘探。 相似文献
943.
提要:距我国中山站以南约400 km的格罗夫山是普里兹造山带向南极内陆的延伸部分,其基底地体由约在920?910 Ma期间侵入的镁铁质-长英质火成岩和少量中元古代的沉积岩构成,这些岩石仅在泛非期(约570?500 Ma)经历了单相变质-构造旋回,因此是一个典型的泛非期变质地体。泛非期高峰变质作用并不象前人所认为的那样仅为中低压麻粒岩相,而是高达770?840?C、1.18?1.40 GPa,并在随后经历了近等温减压(约0.6 GPa)的P-T演化过程。大规模的A型紫苏花岗岩和花岗岩在同造山-后造山阶段侵位,并造成了麻粒岩地体近等压降温的P-T轨迹。这些花岗质岩石是由长期富集地幔的底侵物质(碱性玄武质岩石)经部分溶融而形成的。结合相邻地质体的研究资料,我们认为普里兹造山带可能发育在太古宙-格林维尔期基底地体之上,这些基底地体可能与新元古代(?)盖层卷入到了统一的泛非期造山作用过程。在泛非期造山作用过程中,地壳曾被增厚约达40?50 km,而后又经历了厚约20 km的地壳伸展垮塌和剥蚀。所以,普里兹造山带应代表东冈瓦纳陆块内部由板块缝合作用所形成的一条泛非期碰撞造山带。 相似文献
944.
945.
946.
SHILing 《地球空间信息科学学报》2005,8(2):148-151
Parallel machine problems with a single server and release times are generahzatlons ot classical parallel machine problems. Before processing, each job must be loaded on a machine, which takes a certain release times and a certain setup times. All thesesetups have to be done by a single server, which can handle at most one job at a time. In this paper, we continue studying the complexity result for parallel machine problem with a single and release times. New complexity results are derived for special cases. 相似文献
947.
较大地震破裂尺度的一种简单估算 总被引:4,自引:0,他引:4
通过对各向同性均匀介质中两个点源的波形传播的几何性质的分析,提出对较大地震的破裂尺度的估计,可以采用多个子事件的模拟,根据接收台站得到的子事件的视时间差的分布特征,判断震源的实际破裂方向和破裂尺度,甚至仅仅根据宽频带P波(组)的波形宽度就可进行近似的估算。 相似文献
948.
In this paper we show how the quality factor Q may be calculated using a single seismograph station and a number of events recorded on analogue seismograms. We followed Nuttli's (1973) method and extended it to one seismograph station. Using the single station Bulawayo (BUL), we determined a mean Q value of 650 for Zimbabwe. Furthermore, we considered different propagation paths over Zimbabwe as the seismic waves travelled to BUL and found a low Q value of 350 for the Deka fault zone. the Q value of 650 obtained in this study agrees well within error with that of 603 reported by Chow et al. (1980) using the multistation, multi-event method, and lies within the range of Q values (454–759) reported by Xie & Mitchell (1990) using a 'back-project'method to image large-scale lateral variations of Lg coda Q . the results obtained are important as the Q value constitutes part of the input data in seismic hazard calculations. the method may be used to determine Q in regions where there may be only one station with reliable analogue seismogram data. 相似文献
949.
A. Joshi 《Journal of Seismology》2003,7(1):1-17
State of Uttaranchal in the northern part of India in the Garhwal Himalaya was hit by the Chamoli earthquake on 28th March, 1999 (GMT). This earthquake was recorded on a strong motion array installed in this region. The maximum peak ground acceleration of 353 cm/sec2 was recorded at an accelerograph located at the Gopeshwar station at an approximate epicentral distance of 14 km. The simplified method of Midorikawa (1993) has been used to model finite fault responsible for causing the Chamoli earthquake. This method is based on the Empirical Green's Function (EGF) technique of Irikura (1986).Modifications in this method have been made to include layered earth model and transmission effects at each boundary by Joshi (2001). Rupture causing the Chamoli earthquake is placed in two structural models of the earth in this work: one is a homogeneous half space and other is the multi layered earth model. Comparison in terms of root mean square error (RMSE) is made between the simulated and actual strong motion parameters like peak acceleration and duration. It is seen that the introduction of multi layered earth system in this simplified technique is capable of significantly reducing the RMSE in observed and predicted strong motion parameters and defining the attenuation rate for peak ground acceleration of this earthquake. 相似文献
950.
Draft effect on wave action with a semi-infinite elastic plate 总被引:1,自引:1,他引:0
1Introduction Wave action on coastal and offshore structuresis investigated by many researches. In the recent pa-pers we can seen that Li et al. (2006) developed athree-dimesional(3D) numerical model for obliquewave action on vertical walls, Li et al. (20… 相似文献