Using X‐ray observations to identify the particle acceleration mechanisms in VHE SNRs and “dark” VHE sources

Very high energy (VHE) γ‐ray observations have proven to be very successful in localizing Galactic acceleration sites of VHE particles. Observations of shell‐type supernova remnants have confirmed that particles are accelerated to VHE energies in supernova blast waves; the interpretation of the γ‐ray data in terms of hadronic or leptonic particle components in these objects relies nevertheless strongly on input from X‐ray observations. The largest identified Galactic VHE source class consists of pulsar wind nebulae, as detected in X‐rays. Many of the remaining VHE sources remain however unidentified until now. With X‐ray observations of these enigmatic “dark” objects one hopes to solve the following questions: What is the astrophysical nature of these sources? Are they predominantly electron or hadron accelerators? And what is their contribution to the overall cosmic ray energy budget? The paper aims to provide an overview over the identification status of the Galactic VHE source population. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

中心裂纹巴西圆盘压缩载荷下T应力研究

为了研究中心裂纹巴西圆盘试件在压缩载荷作用下T应力的解析计算方法,通过权函数法推导出集中载荷作用下T应力的显式表达式,进而得到分布载荷作用下的T应力表达式。与边界配位法进行对比,所得公式优点在于任意相对裂纹长度和任意加载角下的T应力值都能较容易的精确得到。进一步分析表明,分布载荷与集中载荷作用下T应力的偏差随着载荷分布角的增加而增加。集中载荷作用下,相对裂纹长度固定时,T应力随着加载角的增大而增大。中心裂纹巴西圆盘纯I型与纯II型断裂试验时,大多数情况下的T应力都为负值。T应力值对中心裂纹巴西圆盘测定断裂韧度试验有影响,想要通过使T应力为0来消除这种影响是很难达到目的的。     

Offshore wind decommissioning regulations and workflows in the Outer Continental Shelf United States

Decommissioning regulations for offshore renewable energy facilities require that all facilities be removed and the seafloor cleared of all obstructions at the end of the life of the lease. The purpose of this paper is to provide an overview of the expected workflows and stages of decommissioning that are likely to arise for offshore wind farms, to describe the exposure and liability of the parties involved and to compare offshore wind and oil and gas decommissioning. An alternative method for turbine removal is proposed which, if feasible, will reduce decommissioning cost. The objectives of a bonding program are motivated and discussed.     

复合隔震支座在网格屋盖结构中的应用研究

将铅芯橡胶隔震垫与碟簧组合形成复合隔震垫,并应用于网格屋盖结构,利用串联弹簧模型预估铅芯橡胶隔震垫参数,利用单质点弹簧模型预估碟簧参数,结合实际工程,进行了模态分析、水平地震动时程分析及竖向地震动时程分析,表明复合隔震技术降低屋盖、下部结构加速度反应60%左右,降低由于地震引起的基顶反力约30%,但水平地震下隔震屋盖的侧移增大显著,应引起注意;文中提出的隔震垫参数预估模型得到了地震动时程分析的验证,可为工程参考。     

Amplification and variability of the AGN X‐ray emission due to microlensing

We consider the contribution of microlensing to the AGN Fe Kα line and X‐ray continuum amplification and variation. To investigate the variability of the line and X‐ray continuum, we studied the effects of microlensing on quasar X‐ray spectra produced by crossing of a microlensing pattern across a standard relativistic accretion disk. To describe the disk emission we used a ray tracing method considering both metrics, Schwarzschild and Kerr. We found that the Fe Kα and continuum may experience significant amplification by a microlensing event (even for microlenses of very small mass). Also, we investigate a contribution of microlensing to the X‐ray variability of high‐redshifted QSOs, finding that cosmologically distributed deflector may contribute significantly to the X‐ray variability of high‐redshifted QSOs (z > 2). (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Measurement of the longitudinal magnetic-field component for FU Ori

The Main Stellar Spectrograph of the 6-m Special Astrophysical Observatory telescope equipped with a polarimetric analyzer was used to measure the longitudinal magnetic-field component of FU Ori on January 24, 2002. The following (3σ) upper limits were obtained for the magnetic field B_‖: B_‖<350–400 G in the formation region of Fe I, Ni I, and Ca I absorption lines (disk + wind), and B_‖<200 G in the formation region of the absorption component of the Hα line with a P Cyg profile. We conclude that the strength of a large-scale magnetic field capable of collimating the disk wind does not exceed 300 G. For the region where the emission component of the Hα line is formed, we found that B_‖<100 G. Such a low value may have been obtained because the magnetic field lines in this region were almost perpendicular to the line of sight at the time of our observations.     

Estimating the interstellar extinction and the contribution from an accretion shock to the formation of emission continuum in DS Tau and DG Tau

We analyze the UV spectra of the young stars DG Tau and DS Tau taken with the STIS spectrograph from the Hubble Space Telescope. For these stars, we found the upper limits of the interstellar extinction A _V . Their values proved to be lower than those obtained by other authors from optical observations. For DS Tau, DG Tau, and T W Hya, we also determined the ratio of theflux in the C IV 1550 doublet lines to the excess continuum flux. It proved to be an order of magnitude lower than its value predicted by the accretion-shock (AS) models of Lamzin (1998) and Calvet and Gullbring (1998). It thus follows that for these stars, the emission continuum originates mainly in the accretion disk and/or the boundary layer rather than in the AS, as has been thought previously. Since a similar conclusion has previously been reached for DR Tau, T Tau, and RY Tau, we may assume that the disks around most young stars reach the stellar surface and accretion mainly proceeds through the boundary layer.     

Indirect Imaging of the Accretion Disk Rim in W Crucis

The eclipsing binary W Crucis belongs to the rare group of strongly interacting binaries, which are believed to be shortly after the first and rapid mass transfer between components, prior to the Algol phase. New 7-colour photometric measurements in the Geneva system are presented for this long period binary. Several consecutive cycles were covered, which revealed rather complex light curves with pronounced bumps and asymmetries in the eclipse shoulders, as well in out-of-eclipse brightness. We modelled light curves with a variant of Rutten’s 3D eclipse-mapping method, which makes it possible to indirectly image the accretion disk rim. A patchy structure has emerged, which explains the rather erratic and complex light curve and its cycle-to-cycle variations.     

含粘滞性弱磁化吸积盘的轴对称脉动不稳定性

本文讨论了一种含扩散型粘滞的弱磁化等温吸积盘模型，在此模型中研究了扩散型粘滞、垂向磁场Bz和环向磁场B对轴对称脉动不稳定性的影响．结果表明，对于轴对称扰动，一般情况下盘内存在四种轴对称振荡模式．其中二种模式是脉动不稳定的，粘滞和磁场对它们表现为非稳因素；而另外二种模式是稳定的，粘滞和磁场对它们表现为致稳因素．此外我们还注意到，Bz和B主要影响近轴向的脉动不稳定性，扩散型弱粘滞主要影响径向脉动不稳定性．     

VAX计算机及图象系统硬磁盘扩充

本文介绍了为VAX计算机系统扩充硬磁盘以及为ARIES-Ⅱ图象处理系统建立图象伪磁盘的方法及步骤。