Time-dependent ionization in the envelopes of type II supernovae at the photospheric phase     

M. Sh. Potashov  S. I. Blinnikov  V. P. Utrobin 《Astronomy Letters》2017,43(1):36-49

The importance of allowance for the time-dependent effect in the kinetics at the photospheric phase during a supernova explosion has been confirmed by several independent research groups. The time-dependent effect provides a higher degree of hydrogen ionization in comparison with the steadystate solutions and strengthens the Hα line in the resulting simulated spectrum, with the intensity of the effect increasing with time. However, some researchers argue that the time-dependent ionization effect is unimportant. Its allowance leads to an insignificant strengthening of Hα in their modeling only in the first days after explosion. We have demonstrated the importance of the time-dependent effect with the models of SN 1999em as an example using the new original LEVELS software package. The role of a number of factors that can weaken the time-dependent effect has been checked. We have confirmed that the intensity of the effect is affected by the abundance of metal admixtures in the envelope, while the addition of extra levels to the model hydrogen atom weakens the time-dependent effect to a lesser degree and never removes it completely.  相似文献   

CSEM technology as a value driver for hydrocarbon exploration     

Jonny Hesthammer  Aristofanis Stefatos  Mikhail Boulaenko  Alexander Vereshagin  Peter Gelting  Torolf Wedberg  Gregor Maxwell 《Marine and Petroleum Geology》2010

The use of the controlled source electromagnetic (CSEM) method as a risk reduction tool in marine hydrocarbon exploration is gaining increased acceptance in the oil industry. This is related to the ability to map resistivity contrasts in the sub-surface and thus aid the detection of hydrocarbons which are typically more resistive than surrounding rocks. Whereas acoustic (seismic) energy allows for mapping sub-surface structures that may contain hydrocarbons, electromagnetic (EM) energy can often say something about the fluids contained within the structures. Numerous successful CSEM case stories have been published over the past several years. However, there are also quite a few stories about “failure”-cases, although not well documented in the literature. Such “failure”-cases may reflect the lack of understanding of the CSEM technology and how CSEM data can act as a value driver. In order to understand this, it is necessary to handle uncertainties and decisions associated with the technology, These include geological uncertainties, noise models, survey designs, forward modelling parameters, inversion/migration parameters and pre-processing of real data. A proper handling of these uncertainties and decisions will aid in defining and constraining the chance of geologic success and geologic-success-case net present value for prospects prior to drilling wells. As such, the CSEM technology has a significant potential to increase exploration efficiency, if applied correctly.  相似文献   

Gas seeps in Lake Baikal—detection, distribution, and implications for water column mixing   总被引：4，自引：4，他引：0  

Nikolay Grigorievich Granin  Mikhail M. Makarov  Konstantin M. Kucher  Ruslan Y. Gnatovsky 《Geo-Marine Letters》2010,30(3-4):399-409

Echo sounders served to locate a large number of shallow- and deepwater gas seeps at the bottom of all three basins of Lake Baikal during the years 2005 to 2008. A substantial proportion of the shallow gas seeps was located near the delta of the Selenga River, and at the Posolskii uplift. Deepwater gas seeps were recorded at the lake bed both inside and outside of areas where a bottom-simulating reflector was identified in seismic profiles. By monitoring the activity of gas emissions at the gas seeps, times of episodic gas ebullition could be distinguished from times of persistent gas bubble streams. A maximum gas flare height of more than 950 m above the bottom was recorded at the St. Petersburg mud volcano located in the central basin of Lake Baikal. Based on calculations from echo sounder data, the ascent velocity of gas bubbles reached 40 cm/s. In the area of gas seepage, there was a thick near-bottom layer, in which the gradient of water temperature was equal to the adiabatic gradient. This implies complete mixing of the water close to the lake bed, resulting from ascending gas bubbles released at seep sites. Analyses of vertical temperature profiles indicate possibly localized upwelling up to the lake surface when gas emissions are intensive.  相似文献   

综合数字区域模型和大范围有机废弃产品处理的测试系统的开发     

Sergey Polyansky Mikhail Sykhanov Vladimir Tikunov 《地球信息科学学报》2007,9(1):73-77

综合数字区域模型在区域可持续发展的任何模型实现中都是不可或缺的,而空间数据基础设施为综合数字区域模型提供了一个可靠的基础。其可以很方便地在地图信息或者直接在地理信息系统(GIS)内形成。这种GIS系统具有开发良好的模型函数,能够集成专家系统,也能被设计全尺度多媒体产品。GIS允许集成不同的信息资源、模型、可视化和分析、各种假设的详尽细节和为诸如自然-社会-经济等的复杂系统提供可选开发方案。一个综合辅助信息系统的结构包括紧密相关的社会-政治、经济(或生产)、自然资源和环境模块。它提供了对于不同区域范围社会生态系统的全面描述,显示了自然和人类资源的重要性。人们在这个研究领域将会谈及自然和社会管理。根据它们的变化层次体系(从全局范围到局部范围)可以描述所有专题,并且考虑在不同尺度上描述的现象的专业特征。超媒体系统原理可以通过链接集成主题来实现。这种系统的日益复杂性使得系统的智能化成为必要,专家系统和神经元网络可以从很复杂并且非常模糊的问题中得出可行的解决方案。现代GIS配有很多设备,对用户来说,这使得用基础地图和互联网获取必要的数据来编制专题图成为可能。数学建模的专业方法具有特殊的重要性,特别是那些旨在追求在区域变换到可持续发展模型时设想的详尽细节的方法。最高级的AIS能作为全尺度的决策支持系统使用。莫斯科国立大学试图实现上述思想,开发了俄罗斯可持续发展信息系统框架,特以俄罗斯南部地区为一案例。该示例一方面作为更大区域即国家的一部分进行描述,另一方面作为一个或多或少、基于资源发展的单元进行描述。也能对区域发展战略和改革措施提出建议。我们已经对所有俄罗斯地区进行了分类,并且指出了不同组(工业、农业等)的最典型代表。将精心设计几个系统的区域分支来描述整个国家的不同地域类型。计算机辅助信息系统提供用户以各种各样传统地图集的计算机的模拟,为决策者对未来的设计和区域发展变量评估等创造了条件。我们正在开发一个大范围有机废弃产品处理的测试GIS系统。其主要目标是为在废弃物储存和掩埋场所的生物降解进行方法研究。其应用包括:存放生活和工业废品的场所的使用和改进(包括工业和农业的场所和废品产生的地方);污水处理设备的建设和重建等。  相似文献