东海西湖凹陷第三系反转构造及其对油气聚集的影响

东海西湖第三纪凹陷经历了早期裂陷和晚期挤压的构造作用,形成了现今规模宏大的反转构造。反转构造是先存的张性断裂后期受到挤压逆冲反转而形成的一种挤压构造与拉伸构造在垂向上叠加的复合构造。按反转强度的差异,本区的反转构造可划分为简单断展型和穿透断展型2种基本类型;按反转构造的几何样式,又可分为简单后冲反转、复合“Y”字型反转、“火”字型反转和花状反转等。凹陷内发育有东缘、中部、西斜坡边缘等3个反转构造带。沿中央凹陷带的反转作用最强,东缘次之,西斜坡边缘最弱。     

An algorithm to resolve γ-rays from charged cosmic rays with DAMPE

The DArk Matter Particle Explorer(DAMPE),also known as Wukong in China,which was launched on 2015 December 17,is a new high energy cosmic ray and γ-ray satellite-borne observatory.One of the main scientific goals of DAMPE is to observe Ge V-Te V high energy γ-rays with accurate energy,angular and time resolution,to indirectly search for dark matter particles and for the study of high energy astrophysics. Due to the comparatively higher fluxes of charged cosmic rays with respect to γ-rays,it is challenging to identify γ-rays with sufficiently high efficiency,minimizing the amount of charged cosmic ray contamination. In this work we present a method to identify γ-rays in DAMPE data based on Monte Carlo simulations,using the powerful electromagnetic/hadronic shower discrimination provided by the calorimeter and the veto detection of charged particles provided by the plastic scintillation detector. Monte Carlo simulations show that after this selection the number of electrons and protons that contaminate the selected γ-ray events at～10 Ge V amounts to less than 1% of the selected sample.Finally,we use flight data to verify the effectiveness of the method by highlighting known γ-ray sources in the sky and by reconstructing preliminary light curves of the Geminga pulsar.     

黄土河谷场地地形放大效应的研究

使用黄土河谷场地模型对地震动峰值加速度和频谱特征进行研究。结果表明,不同工况下各观测点PGA的放大比呈现出不同的变化规律。分析山顶和山谷各点的傅里叶谱以及谱比发现,在地形和土层共同作用下的放大效应是各自单独作用下放大效应的乘积。     

Porosity Distribution Characteristics and Geological Analysis of Brine Storage Medium in the Qaidam Basin,Western China

Underground brine is an unusual water resource that contains abundant mineral resources. It is distributed widely in the Qaidam Basin, western China, a hyperarid inland basin located in the northern Tibetan Plateau. Pores in the brine storage medium act as storage space and transmission channels of underground brine. Therefore, the porosity of brine storage medium determines its ability to store brine. In this study, Mahai Salt Lake was used as the research area as a modern saline lake located in the north area of the Qaidam Basin. A total of 100 porosity samples were collected from eight sampling points in two profiles of the research area at sampling depths of 1.30–314.78 m. The porosity distribution characteristics and influencing factors in brine storage medium were analysed according to the measured porosity data. Based on analysis of the pore structure characteristics, the brine storage medium contains intercrystalline pores, unlike conventional freshwater storage mediums. Moreover, the primary salt rock is susceptible to dissolution by lighter brine, facilitating the formation of secondary porosity. Due to the formation of secondary pores, a porosity greater than 20% remains even at buried depths greater than 100 m. Based on the geological statistical analysis, due to the geographic location, salt formation time, and depositional environment, the porosity values of Mahai Salt Lake do not exhibit a wider distribution, but also show more extreme values than a nearby salt lake. Based on the porosity characteristics by depth, due to the presence of secondary pores, flooding, stratigraphic static pressure, and other factors, porosity shows fluctuations with increasing depth.     

Investigations into the thermal non-equilibrium of W UMa-type contact binaries

Traditionally, some physical details(e.g., magnetic braking, energy transfer, angular momentum loss, etc.) have to be taken into consideration during investigations into the evolution of contact binaries. However, the real evolutionary processes which usually contain several of these physical mechanisms are very complicated as a result of strong interaction between components. To avoid dealing with these factors, a linear relationship is applied to the temperatures of components. It is found that the higher the mass ratio(M_2/M_1) of a contact system, the weaker the deviation from thermal equilibrium.On this basis, a variation trend of fill-out factor(f) changing with mass ratio can be inferred, which is consistent with observations. Moreover, if we stick to this point of view, it should be natural that the number of semi-detached binaries in the predicted broken-contact phase of relaxation oscillations is less than the number in the contact phase.     

PHoToNs–A parallel heterogeneous and threads oriented code for cosmological N-body simulation

We introduce a new code for cosmological simulations, PHo To Ns, which incorporates features for performing massive cosmological simulations on heterogeneous high performance computer(HPC) systems and threads oriented programming. PHo To Ns adopts a hybrid scheme to compute gravitational force, with the conventional Particle-Mesh(PM) algorithm to compute the long-range force,the Tree algorithm to compute the short range force and the direct summation Particle-Particle(PP) algorithm to compute gravity from very close particles. A self-similar space filling a Peano-Hilbert curve is used to decompose the computing domain. Threads programming is advantageously used to more flexibly manage the domain communication, PM calculation and synchronization, as well as Dual Tree Traversal on the CPU+MIC platform. PHo To Ns scales well and efficiency of the PP kernel achieves68.6% of peak performance on MIC and 74.4% on CPU platforms. We also test the accuracy of the code against the much used Gadget-2 in the community and found excellent agreement.     

Fermi/LAT observations of lobe-dominant radio galaxy 3C 207 and possible radiation region of γ-rays

3 C 207 is a lobe-dominant radio galaxy with a one sided jet and bright knots, spanning a kpcMpc scale, which have been resolved in the radio, optical and X-ray bands. This target was confirmed as a γ-ray emitter with Fermi/LAT, but it is uncertain whether the γ-ray emission region is the core or knots due to the low spatial resolution of Fermi/LAT. We present an analysis of its Fermi/LAT data acquired during the past 9 years. Different from the radio and optical emission from the core, it is found that theγ-ray emission is steady without detection of flux variation at over a 2σ confidence level. This likely implies that the γ-ray emission is from its knots. We collect the radio, optical and X-ray data of knot-A,the closest knot from the core at 1.4′′, and compile its spectral energy distribution(SED). Although the single-zone synchrotron+SSC+IC/CMB model that assumes knot-A is at rest can reproduce the SED in the radio-optical-X-ray band, the predicted γ-ray flux is lower than the LAT observations and the derived magnetic field strength deviates from the equipartition condition by 3 orders of magnitude. Assuming that knot-A is moving relativistically, its SED from radio to γ-ray bands would be represented well with the single-zone synchrotron+SSC+IC/CMB model under the equipartition condition. These results likely suggest that the γ-ray emission may be from knot-A via the IC/CMB process and the knot should have relativistical motion. The jet power derived from our model parameters is also roughly consistent with the kinetic power estimated with radio data.     

Geochronology and geochemistry of Baicaogou tuff in Yanji,NE China and its tectonic implications for Early Cretaceous

The authors studied zircon U-Pb age and geochemical data of Baicaogou tuff in Yanji,Jilin Province.The results indicate that the rocks formed in Early Cretaceous( 125. 6 ± 2. 3 Ma). Geochemically,these tuffs have high Si O2 and total Na2 O + K2 O,low Mg O and Fe O,and they belong to metaluminous series,the rock are enriched in LREEs and LILEs,depleted in HREEs and HFSEs such as Nb,Ta,Ti,and P,exhibiting an affinity to I-type granite. All these characteristics implied that the volcanic rocks were derived from partial melting of lower crust. Combined with the geochronology and geochemical features of the coeval igneous rocks within NE China,it is concluded that Yanji area was in a back-arc extensional setting in response to the subduction of the Paleo-Pacific Plate beneath the Eurasian Plate.     

Statistical landslide susceptibility assessment in a dynamic environment: A case study for Lanzhou City,Gansu Province,NW China

This study presents a statistical landslide susceptibility assessment (LSA) in a dynamic environment. The study area is located in the eastern part of Lanzhou, NW China. The Lanzhou area has exhibited rapid urbanization rates over the past decade associated with greening, continuous land use change, and geomorphic reshaping activities. To consider the dynamics of the environment in the LSA, multitemporal data for landslide inventories and the corresponding causal factors were collected. The weights of evidence (WofE) method was used to perform the LSA. Three time stamps, i.e., 2000, 2012, and 2016, were selected to assess the state of landslide susceptibility over time. The results show a clear evolution of the landslide susceptibility patterns that was mainly governed by anthropogenic activities directed toward generating safer building grounds for civil infrastructure. The low and very low susceptibility areas increased by approximately 10% between 2000 and 2016. At the same time, areas of medium, high and very high susceptibility zones decreased proportionally. Based on the results, an approach to design the statistical LSA under dynamic conditions is proposed, the issues and limitations of this approach are also discussed. The study shows that under dynamic conditions, the requirements for data quantity and quality increase significantly. A dynamic environment requires greater effort to estimate the causal relations between the landslides and controlling factors as well as for model validation.     

阿尔金铅、钕、锶、氩、氧同位素研究及其早期演化

根据铅、钕、锶、氩、氧等同位素体系及其年代学研究，阿尔金在其早期演化阶段中存在２７９０—２５９０、１８８３—１７０４、５７５和４７０—４２０Ｍａ４个构造热事件，各自具有不同的性质和时代意义。