应力场演化与强震间相互作用的有限元模拟研究

针对川滇地区,在大量搜集前人资料和结果的基础上,建立了包括上地壳、中地壳、下地壳、上地幔等4层结构的三维有限元模型。通过反复调试,确定了其边界条件。然后计算了川滇地区背景应力场、断层蠕动产生的应力场和强震触发的应力场,以及它们的动态变化。结果表明后续地震大多发生在前面地震引发的库仑破裂应力正值区,前一地震对后续地震有一定的触发作用,强震是在较高的应力背景下成组发生的。这对判断、识别地震异常,提高地震预测水平有着很大的意义。     

长江三峡坝区的雷暴规律

利用宜昌站１９６１～１９９４年的逐日气象资料,较为详细地分析了长江三峡坝区（宜昌地区）雷暴现象的演变规律,着重讨论了雷暴的年际变化、月际分布特征及日变化情况,为长江三峡大江截流及工程建设提供参考。     

TYSC—3Q测井仪数据采集方法改进

ＴＹＳＣ－３Ｑ型数字测井仪目前在煤田地质勘探中大量地使用着,但其承仪器配套的数据采集软件因开发时间过早,已不能适合现在地计算机软件系统。本文从软、硬件两个方面论述了新的数据采集方法,并给出了采用Ｃ程序设计语言实现的方案。     

浅谈中小型专业图书馆期刊文献资源开发利用

为搞好对地质专业图书馆科技期刊收藏和更充分地开发利用科技期刊文献资源,图书馆工作人员需努力提高业务素质;努力做到合理配置,深入课题为读者服务,同时开展多样化服务,拓宽科技期刊文献资源利用领域。     

Windows环境下古地磁样品测试系统的实现

介绍了如何在Ｗｉｎｄｏｗｓ环境下实现实时测控的有关问题与技术。在ＶＢ编程环境下,ＶＢ应用程序通过调用动态链接库（ＤＬＬ）完成硬件中断响应与处理,以及对底层输入／输出Ｉ／Ｏ端口的操作,充分发挥了ＶＢ和Ｃ两种语言的各自优势。     

Millimetric properties of IRAS galaxies – III. Luminosity functions, sub-mm counts and contributions to the sky background

We exploit observations at 1.25 mm with the ESO–SEST telescope of a southern galaxy sample, selected from the IRAS PSC and complete to S ₆₀=2 Jy, to derive the FIR and mm luminosity functions and the conditional probability distributions of FIR and mm luminosity of galaxies. The reliability of these estimates is ensured by the good observed correlation of the far-infrared and mm emissions. This detailed knowledge of the millimetric properties of galaxies is used to simulate the extragalactic sub-mm sky (background intensity, small-scale anisotropy signals and discrete source statistics), which is the target of a variety of ground-based and space observatories. We find, in particular, that a recent tentative detection of a sub-mm background would require, if confirmed, strong evolution with cosmic time of the galaxy long-wavelength emissivity. We finally discuss ways to test such evolution with present and forthcoming facilities: while emphasizing the difficulty of achieving this with large mm telescopes on the ground (because of the poor atmospheric conditions of current sub-mm sites), we mention an interesting opportunity with the long-wavelength camera on ISO . Preliminary results of deep surveys, both from space and from the ground, seem indeed to require excess emission in the past by dusty galaxies with respect to no-evolution predictions.     

The observability of topological defects with ground-based interferometers

Topological defect theories lead to non-Gaussian features on maps of fluctuations of the cosmic microwave background radiation (CMBR), which enable us to distinguish them from maps predicted by standard inflationary models. We have recently presented a maximum entropy method (MEM) which simultaneously deconvolves interferometer maps of CMBR fluctuations, and separates out foreground contaminants. By applying this method to simulated observations using a realistic ground-based interferometer, we demonstrate that it is possible to recover the prominent hotspots in the CMBR maps which delineate individual defects, even in the presence of a significant Galactic foreground.     

Extragalactic source counts and contributions to the anisotropies of the cosmic microwave background: predictions for the Planck Surveyor mission

We present predictions for the counts of extragalactic sources, the contributions to fluctuations and their angular power spectrum in each channel foreseen for the Planck Surveyor (formerly COBRAS/SAMBA ) mission. The contribution to fluctuations owing to clustering of both radio and far-IR sources is found to be generally small in comparison with the Poisson term; however the relative importance of the clustering contribution increases and may eventually become dominant if sources are identified and subtracted down to faint flux limits. The central Planck frequency bands are expected to be 'clean': at high galactic latitude (| b | > 20°), where the reduced galactic noise does not prevent the detection of the extragalactic signal, only a tiny fraction of pixels is found to be contaminated by discrete extragalactic sources. Moreover, the 'flat' angular power spectrum of fluctuations resulting from extragalactic sources substantially differs from that of primordial fluctuations; therefore, the removal of contaminating signals is eased even at frequencies where point sources give a sizeable contribution to the foreground noise.     

The Planck Surveyor mission and gravitational lenses

An extremely sensitive all-sky survey will be carried out in the millimetre/submillimetre waveband by the forthcoming ESA mission Planck Surveyor . The main scientific goal of the mission is to make very accurate measurements of the spatial power spectrum of primordial anisotropies in the cosmic microwave background radiation; however, hundreds of thousands of distant dusty galaxies and quasars will also be detected. These sources are much more likely to be gravitationally lensed by intervening galaxies compared with sources discovered in surveys in other wavebands. Here the number of lenses expected in the survey is estimated, and techniques for discriminating between lensed and unlensed sources are discussed. A practical strategy for this discrimination is presented, based on exploiting the remarkable sensitivity and resolving power of large ground-based millimetre/submillimetre-wave interferometer arrays. More than a thousand gravitational lenses could be detected: a sample that would be an extremely valuable resource in observational cosmology.