Spectral variability in Cygnus X-3

We model the broad-band X-ray spectrum of Cyg X-3 in all states displayed by this source as observed by the Rossi X-ray Timing Explorer . From our models, we derive for the first time unabsorbed spectral shapes and luminosities for the full range of spectral states. We interpret the unabsorbed spectra in terms of Comptonization by a hybrid electron distribution and strong Compton reflection. We study the spectral evolution and compare with other black hole as well as neutron star sources. We show that a neutron star accretor is not consistent with the spectral evolution as a function of L _E and especially not with the transition to a hard state. Our results point to the compact object in Cyg X-3 being a massive,  ∼30 M_⊙  black hole.     

A new model for Vela Jr. Supernova Remnant

We consider Vela Jr. as being the old Supernova Remnant (SNR) at the beginning of the transition from adiabatic to radiative stage of evolution. According to our model, Vela Jr. is situated outside Vela SNR at the distance of 600 pc and its age is 17500 yr. We model the high energy fluxes from Vela Jr. and its broadband spectrum. We find our results compatible with experimental data in radio waves, X- and γ-rays. Our hydrodynamical model of Vela Jr. explains the observed TeV γ-ray flux by hadronic mechanism. The proposed model does not contradict to the low density environment of the SNR and does not need extreme fraction of the explosion energy to be transferred to Cosmic Rays.     

Correlation between local structure and molar ratio of Au (III) complexes in aqueous solution: An XAS investigation

The local and geometrical structure around gold (III) e.g., Au³⁺ ions in aqueous solution with different OH⁻/Cl⁻ molar ratios, has been investigated by X-ray absorption spectroscopy (XAS). X-ray absorption near-edge structure (XANES) spectra of [AuCl_n(OH)_4−n]⁻ solutions have been calculated and the multiple-scattering spectral features have been attributed to Cl d-states, axial water molecules and the replacement of Cl⁻ ligands by OH⁻ ligands. A square–planar geometry for [AuCl_n(OH)_4−n]⁻ with two axial water molecules has been identified. Moreover, a spectral correlation between XANES features and the type of planar atoms has been identified. By extended X-ray absorption fine structure spectra (EXAFS), the planar Au bond distances in the solutions have also been determined, e.g., 2.28 Å for Au–Cl and 1.98 Å for Au–O, respectively. The same EXAFS analysis provides evidence that the peak at about 4.0 Å in solutions with the lowest OH⁻/Cl⁻ molar ratio arises from collinear Cl–Au–Cl multiple-scattering contributions. For the first time, a complete detailed reconstruction of the hydration structure of an Au ion at different pH values has been achieved.     

On the swelling potential of compacted high plasticity clays

We conducted a study of the spatial distributions of seismicity and earthquake hazard parameters for Turkey and the adjacent areas, applying the maximum likelihood method. The procedure allows for the use of either historical or instrumental data, or even a combination of the two. By using this method, we can estimate the earthquake hazard parameters, which include the maximum regional magnitude Mˆ_max, the activity rate of seismic events and the well-known bˆ value, which is the slope of the frequency-magnitude Gutenberg-Richter relationship. These three parameters are determined simultaneously using an iterative scheme. The uncertainty in the determination of the magnitudes was also taken into consideration. The return periods (RP) of earthquakes with a magnitude M ≥ m are also evaluated. The whole examined area is divided into 24 seismic regions based on their seismotectonic regime. The homogeneity of the magnitudes is an essential factor in such studies. In order to achieve homogeneity of the magnitudes, formulas that convert any magnitude to an M_S-surface scale are developed. New completeness cutoffs and their corresponding time intervals are also assessed for each of the 24 seismic regions. Each of the obtained parameters is distributed into its respective seismic region, allowing for an analysis of the localized seismicity parameters and a representation of their regional variation on a map. The earthquake hazard level is also calculated as a function of the form Θ = (Mˆ_max,RP_6.0), and a relative hazard scale (defined as the index K) is defined for each seismic region. The investigated regions are then classified into five groups using these parameters. This classification is useful for theoretical and practical reasons and provides a picture of quantitative seismicity. An attempt is then made to relate these values to the local tectonics.     

东海地区高压-超高压变质带中变质橄榄岩及其原岩和成因类型的判别——以PP1孔和PP3孔为例

本文在总结全球地幔橄榄岩岩石学和地球化学特征的基础上,首次提出了一个用于判别HPUHP变质带中变质橄榄岩原岩及其成因类型的判别图解。该图主要由镁铁总量MgO+（%）和一个参数m+f/si比值构成。另用Al2O3和CaO分别与MgO+（%）制成两个辅助图解,以示方辉橄榄岩和二辉橄榄岩之间在Al2O3和CaO含量上的分界。通过原岩判别结果和研究表明,PP3孔和PP1孔两者在变质组合、原岩成因类型、地球化学和变质条件方面存在一系列的重大差异。分别代表来自两种极端的地球化学类型和两种不同大地构造环境的UHP变质体。PP3钻孔以Ol+Gt+Cpx+Opx+Sp为变质矿物共生组合的含石榴石纯橄岩,其原岩系来自地幔残余成因的方辉橄榄岩遭受UHP变质作用的产物,它以成分高度均一,富Mg（Mg’=92）,极端亏损不相容元素REE（∑REE<1×10-6可称为超亏损型）为特征。在变质相中仍保留原岩的残余矿物铬尖晶石（Sp）,其成分显示蛇绿岩地幔橄榄岩的成分趋势。并出现以Gt和Sp共存相为特征的变质相。据实验结果（klemme,2004）表明该共存相的稳定域的PT条件CrSp可达7Gpa,T1400℃,即形成于200km的地幔深度。综合研究显示该孔变质橄榄岩原岩（方辉橄榄岩）具有大洋岩石圈地幔残余成因的某些印记,而不是同深度原生地幔岩相转变的产物。PP1孔变质橄榄岩是由无水矿物相（Ol+Opx+Cpx+Gt）+含水矿物相（Phl±Chu）组成的石榴石橄榄岩杂岩,其原岩来自两种不同成因的超镁铁岩系列：一为具地幔成因的方辉橄榄岩二辉橄榄岩系列（可能相当于地幔楔中的Al型橄榄岩）,另一部分（少数）来自具岩浆成因的超镁铁岩系列（纯橄岩—异剥橄榄岩—辉石岩组合,可能相当于A2型橄榄岩）。该套变质橄榄岩,以成分高度不均一,极端富集REE（∑REE平均>20×10-6可称为超富集型）和大离子亲石元素（K、Ba、Rb）为特征。这种异常现象并不反映其原岩原有的地球化学特征,它可能是由于在俯冲过程中受到陆壳物质的污染,或壳幔相互作用所致。据该孔变质相中缺乏Sp相,而以Gt为标志的变质相的事实,推断其形成的压力条件应>7Gpa, 即形成的深度应大于200km。上述研究表明在苏鲁UHP变质带中,不仅有来自大陆地幔楔中的地幔残余的UHP变质体,而且首次提出有可能来自大陆俯冲前锋具大洋岩石圈地幔性质的（蛇绿岩型地幔残片）变质体存在,这对揭示该区UHP变质带的形成和演化过程提供了新的信息。     

东海地区高压-超高压变质带中变质橄榄岩及其原岩和成因类型的判别——以PP1孔和PP3孔为例

本文在总结全球地幔橄榄岩岩石学和地球化学特征的基础上,首次提出了一个用于判别HP-UHP变质带中变质橄榄岩原岩及其成因类型的判别图解.该图主要由镁铁总量MgO+(%)和一个参数m+f/si比值构成.另用Al2O3和CaO分别与MgO+(%)制成两个辅助图解,以示方辉橄榄岩和二辉橄榄岩之间在Al2O3和CaO含量上的分界.通过原岩判别结果和研究表明,PP3孔和PP1孔两者在变质组合、原岩成因类型、地球化学和变质条件方面存在一系列的重大差异.分别代表来自两种极端的地球化学类型和两种不同大地构造环境的UHP变质体.PP3钻孔以Ol+Gt+Cpx+Opx+Sp为变质矿物共生组合的含石榴石纯橄岩,其原岩系来自地幔残余成因的方辉橄榄岩遭受UHP变质作用的产物,它以成分高度均一,富Mg(Mg'=92),极端亏损不相容元素REE(∑REE<1×10-6可称为超亏损型)为特征.在变质相中仍保留原岩的残余矿物铬尖晶石(Sp),其成分显示蛇绿岩地幔橄榄岩的成分趋势.并出现以Gt和Sp共存相为特征的变质相.据实验结果(klemme,2004)表明该共存相的稳定域的P-T条件Cr-Sp可达7Gpa,T1400℃,即形成于200km的地幔深度.综合研究显示该孔变质橄榄岩原岩(方辉橄榄岩)具有大洋岩石圈地幔残余成因的某些印记,而不是同深度原生地幔岩相转变的产物.PP1孔变质橄榄岩是由无水矿物相(Ol+Opx+Cpx+Gt)+含水矿物相(Phl±Chu)组成的石榴石橄榄岩杂岩,其原岩来自两种不同成因的超镁铁岩系列:一为具地幔成因的方辉橄榄岩-二辉橄榄岩系列(可能相当于地幔楔中的Al型橄榄岩),另一部分(少数)来自具岩浆成因的超镁铁岩系列(纯橄岩-异剥橄榄岩-辉石岩组合,可能相当于A2型橄榄岩).该套变质橄榄岩,以成分高度不均一,极端富集REE(∑REE平均>20×10-6可称为超富集型)和大离子亲石元素(K、Ba、Rb)为特征.这种异常现象并不反映其原岩原有的地球化学特征,它可能是由于在俯冲过程中受到陆壳物质的污染,或壳-幔相互作用所致.据该孔变质相中缺乏Sp相,而以Gt为标志的变质相的事实,推断其形成的压力条件应>7Gpa, 即形成的深度应大于200km.上述研究表明在苏鲁UHP变质带中,不仅有来自大陆地幔楔中的地幔残余的UHP变质体,而且首次提出有可能来自大陆俯冲前锋具大洋岩石圈地幔性质的(蛇绿岩型地幔残片)变质体存在,这对揭示该区UHP变质带的形成和演化过程提供了新的信息.     

Effect of alpha-damage annealing on apatite (U–Th)/He thermochronology

Recent data on He diffusion challenge the temperature sensitivity of apatite (U–Th)/He thermochronology: the damage induced by recoil of U and Th decay series during emission of α particles (α-recoil damage) has been proposed to modify He-diffusion properties through time. However, we propose that annealing of these irradiation defects may be an important phenomenon and may be significant in case of slowly-cooled or reheated basement rocks. To test this hypothesis, we developed a quantitative model including an explicit treatment of α-recoil damage, annealing, and their effect on He-diffusion kinetics, and calibrate it against literature data. Our model is based on two hypotheses: (1) helium is in equilibrium between an apatite crystal and its defects and (2) alpha-recoil damage annealing can be described analogously to fission-track annealing. This model has been embedded into a Monte Carlo simulation of helium production/ejection/diffusion and applied to data from the French Massif Central; a complex slowly-cooled terrain with burial reheating, where the thermal history has been constrained by previous fission-track (FT) data including FT length distributions. (U–Th)/He ages are close to the FT ages from the same samples and are generally reproducible among replicates, but some samples present He-age dispersion that is not correlated with crystal size. Our model reproduces the Massif Central data very well except for three samples where He ages are older than corresponding FT ages. We show that annealing of irradiation damage has an important impact on retentivity of helium and that the He content, [He] is only a rough approximation of the damage level. In particular our results show that independence of He ages on crystal sizes, in case of reheated samples, is a clear indication of the higher He retentivity induced by α-recoil defects and that an explicit treatment of defect annealing is required for a correct interpretation of (U–Th)/He ages in such a case. More generally a correlation with the crystal size can bring information on the thermal path only if the age of defects, well represented by the fission-track age, is available, due to the dependence of the partial retention zone on damages. Conversely, in case of rapid cooling or for samples having low U and Th contents, damage effects can be ignored without significant effects on He ages.     

Pile foundation analysis and design using experimental data and 3-D numerical analysis

Capacity based design of pile foundations limits the soil-structure interaction mechanism to group bearing capacity estimation, neglecting, in most cases, the contribution of the raft. On the other hand, a straightforward, nonlinear, 3-D analysis, accounting for soil and structural nonlinearities and the effects arising from pile–soil–pile interaction, would be extremely high CPU-time demanding and will necessitate the use of exceptionally powerful numerical tools. With the aim of investigating the most efficient, precise, and economical design for a bridge foundation, a hybrid method, compatible with the notion of sub-structuring is proposed. It is based on both experimental data and nonlinear 3-D analysis. The first step to achieve these targets is a back-analysis of a static pile load test, fitting values for soil shear strength, deformation modulus, and shear strength mobilization at the soil–pile interface. Subsequently, the response of 2 × 2 and 3 × 3 pile group configurations is numerically established and the distribution of the applied load to the raft and the characteristic piles is discussed. Finally, a design strategy for an optimized design of pile raft foundations subjected to non-uniform vertical loading is proposed.     

Peierls dislocation modelling in perovskite (CaTiO<Subscript>3</Subscript>): comparison with tausonite (SrTiO<Subscript>3</Subscript>) and MgSiO<Subscript>3</Subscript> perovskite

We present here a numerical modelling study of dislocations in perovskite CaTiO₃. The dislocation core structures and properties are calculated through the Peierls–Nabarro model using the generalized stacking fault (GSF) results as a starting model. The GSF are determined from first-principles calculations using the VASP code. The dislocation properties such as collinear, planar core spreading and Peierls stresses are determined for the following slip systems: [100](010), [100](001), [010](100), [010](001), [001](100), [001](010), and All dislocations exhibit lattice friction, but glide appears to be easier for [100](010) and [010](100). [001](010) and [001](100) exhibit collinear dissociation. Comparing Peierls stresses among tausonite (SrTiO₃), perovskite (CaTiO₃) and MgSiO₃ perovskite demonstrates the strong influence of orthorhombic distortions on lattice friction. However, and despite some quantitative differences, CaTiO₃ appears to be a satisfactory analogue material for MgSiO₃ perovskite as far as dislocation glide is concerned.     

MERSI和MODIS卫星监测京津冀及周边地区PM2.5浓度

京津冀及周边地区是中国PM_(2.5)污染最重的区域之一,利用卫星遥感技术监测大范围的PM_(2.5)时空分布变化是一种先进的重要手段。本研究首先基于暗像元算法利用FY-3B/MERSI与AQUA/MODIS对京津冀及周边区域进行了遥感AOT反演和验证分析;然后,引入气象资料和地面观测资料利用GWR模型反演了区域PM_(2.5)浓度,并对遥感反演结果进行了交叉验证评估,综合对比分析了MERSI和MODIS的气溶胶及PM_(2.5)遥感监测能力;最后,利用MERSI数据对2017年第一季度京津冀及周边区域的PM_(2.5)月均浓度时空分布变化情况进行了初步探索分析。结果表明:FY-3B/MERSI在气溶胶及PM_(2.5)遥感监测能力方面略优于AQUA/MODIS,MERSI反演的1 km分辨率AOT和PM_(2.5)与地面站点实测结果的决定系数R2分别为0.76μg/m~3和0.79μg/m~3,均方根误差分别为0.26μg/m~3和28μg/m~3,平均绝对误差分别为0.16μg/m~3和15μg/m~3,能基本满足对京津冀及周边区域PM_(2.5)的精细化监测需要。2017年第一季度京津冀及周边区域PM_(2.5)月均浓度遥感监测结果表明该区域的PM_(2.5)空间分布格局与地形地貌关系密切,高值区整体上沿太行山脉成带成片;从时间变化来看,1—3月呈逐月下降的趋势,其中3月份PM_(2.5)区域浓度较1月和2月有大幅下降。这说明FY-3\MERSI遥感反演产品能为环境质量监测和环境管理工作效果评估提供有效参考,本研究对国产卫星在大气环境遥感业务中的大力发展应用有重要参考意义。