Modeling the WMAP large-angle anomalies as an effect of a local density inhomogeneity     

Li-Ping He  Quan Guo National Astronomical Observatories  Chinese Academy of Sciences  Beijing  China  Graduate University of Chinese Academy of Sciences  Beijing 《中国天文和天体物理学报》2010,10(2)

We investigate large-angle scale temperature anisotropy in the Cosmic Microwave Background (CMB) with the Wilkinson Microwave Anisotropy Probe (WMAP) data and model the large-angle anomalies as the effect of the CMB quadrupole anisotropies caused by the local density inhomogeneities. The quadrupole caused by the local density inhomogeneities is different from the special relativity kinematic quadrupole. If the observer inhabits a strong inhomogeneous region, the local quadrupole should not be neglected. We ...  相似文献   

Multicolor photometry of the galaxy cluster A98: substructures and star formation properties     

Li Zhang  Qi-Rong Yuan  Xu Zhou  Zhao-Ji Jiang  Yan-Bin Yang  Jun Ma  Jiang-Hua Wu  Zhen-Yu Wu 《中国天文和天体物理学报》2010,10(1)

An optical photometric observation with the Beijing–Arizona–Taiwan–Connecticut (BATC) multicolor system is carried out for A98 (z = 0.104),a galaxy cluster with two large enhancements in X-ray surface brightness.Spectral energy distributions (SEDs) covering 15 intermediate bands are obtained for all sources detected down to V ～ 20 mag in a field of 58 × 58 .After star–galaxy separation with colorcolor diagrams,a photometric redshift technique is applied to the galaxy sample for further membership determinat...  相似文献   

The study of Seyfert 2 galaxies with and without infrared broad lines     

Hong-Bing Cai    Xin-Wen Shu  Zhen-Ya Zheng  Jun-Xian Wang CAS Key Laboratory for Research in Galaxies  Cosmology  Department of Astronomy  University of Science  Technology of China  Hefei  China National Time Service Center  CAS  Xi’an  China 《中国天文和天体物理学报》2010,10(5)

From the literature,we construct a sample of 25 Seyfert 2 galaxies (S2s)with a broad line region (BLR) detected in near infrared (NIR) spectroscopy and 29with NIR BLRs which were not detected. We find no significant difference between the nuclei luminosity (extinction-corrected [OIII] 5007) and infrared color f60/f25 between the two populations,suggesting that the non-detections of NIR BLRs could not be due to low AGN luminosity or contamination from the host galaxy. As expected,we find significantly lower X-ray obscurations in Seyfert 2s with NIR BLR detection,supporting the unification scheme. However,such a scheme was challenged by the detection of NIR BLRs in heavily X-ray obscured sources,especially in six of them with Compton-thick X-ray obscuration. The discrepancy could be solved by the clumpy torus model and we propose a toy model demonstrating that IR-thin Xray-thick S2s could be viewed at intermediate inclinations and compared with those IR-thick X-ray-thick S2s. We note that two of the IR-thin X-ray-thick S2s (NGC 1386 and NGC 7674) experienced X-ray transitions,i.e. from Compton-thin to Comptonthick appearance or vice versa based on previous X-ray observations,suggesting that X-ray transitions could be common in this special class of objects.  相似文献   

Dust growth in protoplanetary disks - a comprehensive experimental / theoretical approach     

Jürgen Blum 《中国天文和天体物理学报》2010,(12)

More than a decade of dedicated experimental work on the collisional physics of protoplanetary dust has brought us to a point at which the growth of dust aggregates can-for the first time-be self-consistently and reliably modeled. In this article, the emergent collision model for protoplanetery dust aggregates, as well as the numerical model for the evolution of dust aggregates in protoplanetary disks, is reviewed. It turns out that, after a brief period of rapid collisional growth of fluffy dust aggregates...  相似文献   

盾构隧道与矿山法隧道接合部施工工艺     

张二海  洪健  吴文涛 《岩土钻凿工程》2010,(1):88-90

深圳地铁2号线蛇海区间采用盾构法＋矿山法施工,但由于受地层及周边环境的限制,隧道接合部难以按原设计进行施工。经过研究比对,实际施工时采用了一种新的施工工艺,问题得以顺利解决,可供类似工程参考。  相似文献   

用地下径流模数法预测山岭隧道涌水量的局限性分析与改进   总被引：1，自引：0，他引：1  

许增荣 《地下水》2010,32(1):49-50,124

地下径流模数法是一种近年来在隧道涌水量预测中应用较广泛的方法,该方法目前在具体使用过程中对有关参数的计算有很大可变性。根据作者在多种地区的工作经验,分析了根据地表水枯水期流量观测数据用该方法预测山岭隧道涌水量的局限性,提出了改进方法及相应的计算公式,并进一步论述了该方法的基本适用条件。  相似文献   

云南安楚高速公路大红田隧道涌水分析     

朱春林  邢志会  唐顺  包梅 《云南地质》2010,29(3):323-327

依据大红田隧道水文地质勘察和监测数据,结合前人已有成果,重点探讨隧道涌水特征、涌水影响范围及地下水消失量,并尝试对断流泉出流进行预测。  相似文献   

粘土中圆形隧道上限解的研究     

尹小军 《岩土工程技术》2010,24(1):20-23

根据极限分析上限理论,基于Davis等人提出的隧道垮落模型,提出了剪切区参数α等于1时的新的隧道垮落模型。由不可压缩性条件和速度连续性条件求出了剪切区速度和间断线表达式,计算了该模型间断线上能量耗损、剪切区能量耗损和总外力所做的功。利用功能原理,求出了稳定率的表达式,并计算了相应的稳定率。从求解结果来看,所得上限解小于Davis等人的结果,因而该上限解将更接近真实解。从与实验结果比较来看,该上限解位于实验值附近,能与实验结果比较好地吻合,从而说明该模型更加接近真实隧道垮落情形。该上限解可为隧道支护提供理论依据。  相似文献   

杭州某顶管下穿钱江二桥的施工影响分析     

吕斌 《中国勘察设计》2010,(3):58-61

杭州某污水处理厂双线圆形管道拟采用顶管隧道施工方案,分别用plaxis软件进行有限元分析和经验法计算得到顶管隧道穿越钱江二桥铁路桥梁引起的地面变形、桩基变形、桩基承载力影响大小数据。结果证明顶管穿越铁路桥,对桥梁影响较小。  相似文献   

综合物探方法在马石店隧道勘察中的应用     

时彦芳 《山东地质》2010,(8):22-24

利用高密度电阻率法和浅层地震波法对309国道马石店隧道进行勘察,以高密度电法为主,浅层地震折射波法相辅助的方法,通过综合比较,可以查明风化层和基岩分界及隐伏构造,为勘察设计提供依据,综合物探方法达到了满意的效果。  相似文献