水泥喷浆桩工程技术在新乡市区住宅楼基础工程的应用实例

新乡市染织厂 9号住宅楼基础工程 ,属于一个典型的老城区改造工程实例。拟建工程场地的环境地质条件很差 ,不能满足建筑设计与施工要求。在分析岩土工程地质资料和深层搅拌桩设计、施工技术的基础上 ,选择水泥喷浆桩复合地基进行处理并获成功 ,取得了良好的社会效益和经济效益。水泥喷浆桩复合地基处理在新乡市区首次应用成功 ,显示了地基处理施工、设计单位的技术实力     

砼地基施工质量的CT检测技术

建筑工程板状砼地基属地下工程,其施工质量的检测与控制难度较大。根据该类工程的特点（面积大,厚度小）,可将其视为二维结构,采用弹性波ＣＴ成像方法检测其施工质量,在工程实践中取得了满意的效果。本文将结合工程实例介绍板状砼地基浇注质量的ＣＴ检测技术,包括弹性波ＣＴ的基本原理、野外数据采集系统的设计以及数据处理方法。     

Landsat时序变化检测综述

时序变化检测已成为当前Landsat数据主流的变化检测方法。本文从检测算法对比、时序数据构建和精度评价等方面对Landsat时序变化检测进行回顾和评述,进而提出Landsat时序变化检测当前所存在的问题,及其所面临的挑战。Landsat时序变化检测算法可大致归纳为轨迹拟合法、光谱-时间轨迹法、基于模型的方法3大类,这些算法大多基于森林扰动提出;变化检测常用指标有波段型、植被指数型、线性变换型、组合型4大类,每类指标的优势不同,可综合多类指标以更全面地检测不同扰动类型。尽管Landsat时序变化检测已取得长足发展,但仍然面临诸多挑战,其中最大挑战是缺少一致性的参考数据集进行变化检测精度评价。     

科学合作地域倾向性研究——以中国雾霾研究为例

科学合作是促进知识传播和共享的重要途径,已有研究表明,地理因素是影响科学合作的主要因素之一。然而,目前针对该问题的研究大多只是从科学计量学的角度,对科学合作强度与地理距离的函数关系进行描述,无法揭示科学合作在空间上的分布特征和内部差异性。因此,本文从地理学的角度,以中国雾霾研究的合作网络为例,通过对文献题录中的位置信息进行解析,将虚拟的科学合作网络映射到地理合作网络。在此基础上,提出了一种考虑地理距离的科学合作网络社区发现方法,挖掘科学合作网络中蕴含的空间聚类特征,从而对科学合作的地域倾向性进行反映。通过比较发现,基于合作频次与地理距离的社区发现算法,能够使社区内部的平均地理距离最小而合作强度最大,既反映了科学合作在地理上的近似性,又体现了科学合作强度特征。该方法能够直观地揭示科学合作中隐含的空间分布模式和联系,对其他复杂网络的地理社区划分也有一定的借鉴意义。     

浅层地震反射在郧西盆地断层探测中的应用与研究

在前期详细地质调查的基础上,对郧西盆地进行针对性的浅层地震反射勘探,并利用地震发射结果来确定断层位置及构造特征。该研究对南水北调中线核心水源区地震安全系统的建设有一定意义。     

Observation and Research of the Transits of Extrasolar Planets

In order to make more accurate estimates of the physical parameters of extrasolar planets, the observation and research on the phenomena of transits of the 7 known stars with the planetary systems TrES-1, TrES-3, XO-2, WASP-1, WASP-2, WASP-3 and HAT-P-7 are carried out with the 1-m reflecting telescope at Shandong University Weihai Astronomical Observatory/Weihai Municipal Astronomical Observatory. The fundamental conditions of the observation and data processing are introduced, and the transit light curves as well as the parameters of some planets derived from them are given. At the same time, when the results are summarized and analyzed, the prospects for the more in-depth and detailed researches which will be further carried out are also described.     

On the use of X-ray and γ-ray telescopes for identifying the origin of electrons and positrons observed by ATIC, Fermi, and PAMELA

X-ray and γ-ray observations can help understand the origin of the electron and positron signals reported by ATIC, PAMELA, PPB-BETS, and Fermi. It remains unclear whether the observed high-energy electrons and positrons are produced by relic particles, or by some astrophysical sources. To distinguish between the two possibilities, one can compare the electron population in the local neighborhood with that in the dwarf spheroidal galaxies, which are not expected to host as many pulsars and other astrophysical sources. This can be accomplished using X-ray and γ-ray observations of dwarf spheroidal galaxies. Assuming the signal detected by Fermi and ATIC comes from dark matter and using the inferred dark matter profile of the Draco dwarf spheroidal galaxy as an example, we calculate the photon spectrum produced by electrons via inverse Compton scattering. Since little is known about the magnetic fields in dwarf spheroidal galaxies, we consider the propagation of charged particles with and without diffusion. Extending the analysis of Fermi collaboration for Draco, we find that for a halo mass ∼10⁹ M_⊙, even in the absence of diffusion, the γ-ray signal would be above the upper limits. This conclusion is subject to uncertainties associated with the halo mass. If dwarf spheroidal galaxies host local magnetic fields, the diffusion of the electrons can result in a signal detectable by future X-ray telescopes.     

Optimized running conditions and sensitivity for direction sensitive detectors of WIMP dark matter

Optimum fill pressures for direction-sensitive dark matter detectors based on tracking in gases are considered. Given the minimum resolvable track length and the gas fill, the Lindhard–Scharf stopping model leads to the existence of an optimum pressure which maximizes the specific event rate R (event rate per unit detector volume). In addition, maximizing the detectibility of the recoil nucleus diurnal asymmetry is considered. Optimum fill pressures are calculated for Ar, CF₄, CS₂ and Xe gas fills, as a function of the WIMP mass and the minimum resolvable track length. The associated minimum target volumes required to achieve currently competitive WIMP-nucleon cross-section sensitivity are also calculated. The standard isothermal sphere model of the galactic WIMP halo is used throughout, but the method could be extended to use any desired WIMP distribution function.     

The sensitivity of the next generation of lunar Cherenkov observations to UHE neutrinos and cosmic rays

We present simulation results for the detection of ultra-high energy (UHE) cosmic ray (CR) and neutrino interactions in the Moon by radio-telescopes. We simulate the expected radio signal at Earth from such interactions, expanding on previous work to include interactions in the sub-regolith layer for single dish and multiple telescope systems. For previous experiments at Parkes, Goldstone (GLUE), and Kalyazin we recalculate the sensitivity to an isotropic flux of UHE neutrinos. We find the published sensitivity for the GLUE experiment to be too high (too optimistic) by an order of magnitude, and consequently the GLUE limit to be too low by an order of magnitude. Our predicted sensitivity for future experiments using the Australia Telescope Compact Array (ATCA) and the Australian SKA Pathfinder (ASKAP) indicate these instruments will be able to detect the more optimistic UHE neutrino flux predictions, while the square kilometre array (SKA) will also be sensitive to all bar one prediction of a diffuse ‘cosmogenic’, or ‘GZK’, neutrino flux.Outstanding theoretical uncertainties at both high-frequency and low-frequency limits currently prevent a reliable estimate of the sensitivity of the lunar Cherenkov technique for UHE cosmic ray (CR) astronomy. Here, we place limits on the effects of large-scale surface roughness on UHE CR detection, and find that when near-surface ‘formation-zone’ effects are ignored, the proposed SKA low-frequency aperture array could detect CR events above 56 EeV at a rate between 15 and 40 times that of the current Pierre Auger Observatory. Should further work indicate that formation-zone effects have little impact on UHE CR sensitivity, observations of the Moon with the SKA would allow directional analysis of UHE cosmic rays, and investigation of correlations with putative cosmic ray source populations, to be conducted with very high statistics.     

2.4m望远镜网络安全初步设计

云南天文台将在2.4m望远镜建立远程观测系统。由于远程观测系统通过网络实现通信,必然会面临网络上的各种威胁。为了保证整个网络系统的安全,避免各种不安全因素造成的损失。在对现在望远镜网络分析基础上设计了安全的网络结构,并实现了具有入侵检测功能的防火墙,这些措施初步保障了2.4m望远镜网络系统的安全。