Absence of a periodic component in the quasar z distribution

The presence of a periodic component in the quasar distribution over redshift z is investigated. The periodicity is analysed for the coordinate ln(1 + z) and for the geodesic cosmological distance using the SDSS and 2dF catalogs (??85 000 quasars). Four different criteria and the Fourier transform method were used to search for periodicity. The analysis shows an absence of a periodic component in the quasar redshift distribution at any significant confidence level.     

The development of asymmetrical folds in a cross-laminated siltstone

A group of folds in alternating pelites and cross-laminated siltstones is described. An interpretation of the finite strain state, in the competent silt layers, is proposed on the basis of an analysis of the angle between cross-lamination and the principal surface of accumulation. Strain magnitudes are greatest in the fold hinge where domains of layer parallel shortening and layer parallel extension are separated by a neutral surface. Strain magnitudes in the fold limbs are small and are largely related to the development of the asymmetry of the folds. In the incompetent pelitic layers, strain in the fold limbs has a large, layer parallel shear component. Deformation in the pelites is accompanied by, and presumably partially achieved by, migration of quartz from areas where there is a tendency for volume to decrease, to areas where it is tending to increase. This process involves local increases in volume of more than 50%.A kinematic model is proposed for development of the folds. It involves early development of small symmetrical folds followed by their modification to asymmetrical, parasitic structures on the limbs of later folds. In the late stages of folding, continued shortening perpendicular to the axial surface orientation is achieved by development of a conjugate crenulation cleavage.     

Acceleration of Selenate Reduction by Alternative Drying and Wetting of Soils

In nature selenate reduction and nitrate denitrification both follow a similar biogeo-chemical mechanism.It has been proved that abiotic stresses such as alternative drying and wetting can exert an important influence on nitrate denitrification as well as on selenate reduction.Our experimental results lend great support to the above conclusion.     

The origin and tectonic significance of asymmetrical meander-belts

In the Hebgen lake area of SW Montana, the Madison and South Fork Rivers occupy the northeast sides of their respective meander-belts. The form of the abandoned meander-loops within these asymmetric meander-belts indicates that they were produced by gradual northeast migration of the active channels. This progressive migration can be related to tectonic tilting produced by regional extensional faulting at a high angle to the original channel-belt axis which ran down a gently sloping outwash cone. Asymmetric channel sandstone bodies in the rock record can be recognized by the preferred dip of successive lateral accretion units in meander loops. Together with soft sediment deformation, facies and thickness variations they may indicate tectonic deformation of the sedimentary surface.     

Reconstruction of the strip brightness distribution in a quasar accretion disk from gravitational microlensing data

A technique is proposed for the successive reconstruction of the branches of the strip brightness distribution for a quasar accretion disk via the analysis of observations of high magnification flux events in the multiple quasar images produced by a gravitational lens. The distribution branches are searched for on compact sets of nonnegative, monotonically nonincreasing, convex downward functions. The results of numerical simulations and application of the technique to real observations show that the solution obtained is stable against random noise. Analysis of the light curve of a high magnification event in image C of the gravitational lens QSO 2237+0305 observed by the OGLE group in summer 1999 has yielded the form of the strip brightness distribution in the accretion disk of the lensed quasar. The results are consistent with the hypothesis that the quasar disk was scanned by a fold caustic. The form of the strip distribution is consistent with the expected appearance of an accretion disk rotating around a supermassive black hole.     

Tsilmanite as a new type of jet

A new type of jet from continental Devonian deposits of the Middle Timan is described. Fragments of Archaeopteris were the substrate for jet formation. Fossils in sandstone layers are characterized by a peculiar spheroidal jointing of organic matter; the material is fusainized completely. The jet is characterized by integration of the properties of classic jet and inertinite. The proper name tsilmanite is suggested for the new type of jet after the place of its discovery.     

浅埋偏压隧道洞口坍方数值分析与处治

某公路隧道在进洞时出现坍方。针对该隧道工程的实际情况,建立数值分析模型,采用ANSYS程序模拟隧道施工力学行为,从围岩塑性区分布、位移以及锚杆和混凝土衬砌内力分布情况分析隧道变形和坍塌发生的原因。结果表明：隧道浅埋偏压、围岩力学性质差及施工支护不当导致坍方。结合工程实际提出洞内加固、地表注浆加固及开挖控制的综合处治方法,取得了理想的效果,为日后类似工程提供借鉴与参考。     

The complex one-sided integrals of Cauchy and Hadamard and application to boundary element method

The definitions of complex integrals of Cauchy and Hadamard with the singular point coinciding with the end point of the integration curve are proposed. It is shown that the new integrals satisfy most of the properties of the regular ones, including the change of variables. It is also shown that the Cauchy principal value (CPV) and Hadamard finite-part (HFP) integrals can be considered as a sum of the new type integrals. The application to numerical solution by the boundary element method (BEM) and the complex hypersingular integral equation (CHSIE) for the multiregions of interacting elastic bodies and bodies with cracks and holes is discussed. The different ways to place the collocation points are considered. The numerical results for the problems of circular hole and circular elastic inclusion in infinite plate indicated that the appropriate choice of the approximating functions leads to a high accuracy of the calculation. Applications of the new technique to geomechanics problems are discussed. © 1998 John Wiley & Sons, Ltd.     

波流环境中射流的大涡数值模拟

采用大涡模拟方法（LES）对波流环境中的垂向圆管射流进行了数值模拟。出口边界采用人工海绵层加零梯度条件以减小数值反射,且保证自由出流;入口边界分别采用线性叠加和非线性叠加的波流边界条件,通过与物理实验数据对比发现,采用非线性叠加的边界条件时模拟精度更高。数模结果表明,在波浪和水流共同作用下,射流体上部出现了较为明显的“水团”现象,射流平均速度矢量较纯流环境中更靠近底床,这与前期实验观察的结果一致。     

Mathematical modeling of a jet in the vicinity of a compact object

An MHD model for the formation of a jet in the vicinity of a compact object with a supersonic accretion regime is constructed, assuming that the plasma is perfectly electrically conducting. A stable, collimated jet of plasma along the z axis symmetric about the plane of the accretion disk is obtained. The parameters of the jet are in good agreement-with available observational data on the structure and properties of jets.     

动水中含污染物冲击射流横向高浓度聚集区的形成机理和特性分析

采用RNG湍流模型对动水中含污染物冲击射流滞止点下游区域的横向浓度分布特征进行了详细的数值研究,并与相应的实验结果进行了比较。分析了下游过渡区内横向高浓度聚集区的形成机理和扩散特性。计算结果表明,冲击效应和横流绕流对冲击射流下游过渡区内的横向浓度分布具有重要的影响。当流速比相对较小时,在靠近对称面以及底层壁射流与环境横流的横向边界附近出现较为明显的横向高浓度聚集区,计算结果表明,冲击效应产生的横向逆压梯度以及横流绕流导致的Scarf涡结构对横向高浓度聚集区的形成起主导作用。     

Acceleration characteristics of a rock slide using the particle image velocimetry technique

2017年四川省茂县新磨村滑坡的启动具有明显的“锁固段”效应。在现场调查基础上,采用高强度脆性材料制作斜坡模型,开展物理模拟试验,重现滑坡变形破坏过程,分析新磨村后山高位顺层滑坡在反倾节理和潜在滑移破裂面控制下的启动机制,结合“锁固段”岩体变形破坏特征、变形监测数据和声发射信号,研究滑坡临滑前兆。试验发现：受上部滑体推挤,滑源区前部“锁固段”岩体沿反倾节理鼓胀剪出,在坡表形成鼓胀裂缝,在斜坡内部形成顺坡向拉裂面,两组破裂面组合形成阶梯状破坏面,构成“锁固段”岩体破坏边界条件。斜坡在上部滑移块体推挤下,中部形成向临空面高速启动的弹射块体,并带动下部倾倒块体向坡外运动,滑坡启动。故对于此类滑坡,可将沿反倾节理剪出形成的鼓胀裂缝视为宏观临滑前兆;同时在“锁固段”屈服阶段,坡表与坡顶的位移比值随时间先快速增长、后平缓,表征滑面逐渐贯通,滑坡各部位变形逐渐趋于协同,滑坡即将失稳。该比值时序曲线的斜率趋近于零可视为此类滑坡的临滑前兆。研究结论对发育反倾节理的顺层边坡失稳预警有理论和实践意义。     

太阳粒子辐射与地球自转非潮汐加速度

太阳粒子（含太阳风粒子和扰动粒子）为地球磁场俘获，由磁尾→磁层→电离层，在高空形成复杂电流系统（发电机原理），引发电磁效应：产生地球叠加磁场；电流与地球磁体力的效应。其中重要的是：持续不断的太阳风粒子引发的一区场向电流，使地球磁转子产生顺向（自转方向）和加速度（电动机原理）。以弥补潮汐摩擦减速和各种内能消耗。同时，高能太阳粒子“核簇射”次级粒子与高层大气核反应产物，参与和促使地球大气圈、水圈、硅铝质陆壳的成生和演化。     

自进式直旋混合射流钻头结构优化与钻孔能力分析

自进式射流钻头作为水力喷射径向钻井技术开采煤系气的核心部件,对钻井效率有决定性影响。为获取直旋混合射流钻头结构的最优参数,采用Fluent数值模拟与室内钻进试验相结合的办法,分析不同钻头结构参数下三维流场的速度特性,给出优化准则,并通过钻进试验加以验证,得到钻头的最优参数:中心孔孔径1.2 mm,叶轮槽槽宽0.7 mm,叶轮长度4.5 mm,叶轮径向长度3.5 mm,倾角45°,混合腔腔长6 mm。并通过理论分析解释了不同参数对钻头钻进速度产生变化的原因,主要是通过影响直旋混合射流中直射流与旋转射流的通量,进而引起射流三维的变化。采用灰色关联分析法得出各参数结构对钻进位移的敏感性系数由高到低依次为:中心孔孔径、叶轮槽宽、叶轮径向长度、混合腔腔长、叶轮倾角、叶轮长度。室内钻进试验结果表明:优化后的射流钻头具有更高的钻进效率,在关联分析中对钻进效率影响最大的是直射流与旋转射流通量,且直旋通量比在0.54时,射流能量分配较合理。研究成果对径向钻井煤层气、天然气开采中钻头的设计与结构优化具有指导意义。      

Measurement of Explosion Acceleration and Analysis of Calibration Error

This paper analyses in detail the error of high and low frequency responses for measuring eplosion acceleration system in the frequency domain. The error caused by measuring system is calculated by means of spectrum analysis of input and output waveforms and different areas enclosed by amplitude-frequency curves. In addition, this paper introduces a method of calibrating impulse accelerometer in the frequency domain by Fourier transform method and presents a formula to determine the sensitivity of accelerometer.     

爆破加速度测量及标定误差分析

本文首先介绍了在频率域上对爆破加速度测量系统的低频响应误差和高频响应误差的详细分析过程,并对输入、输出波形采用频谱分析及计算幅频曲线,用幅频曲线所包围的不同面积来计算经过测量系统后所引起的误差.其次介绍了采用傅里叶变换法如何在频率域上标定冲击加速度计,给出了确定加速度灵敏度的方法.     

水平旋喷桩施工引起周围土体变形分析

水平旋喷桩施工期间,大量高压流体注入土层,引起土层内部产生较大的膨胀作用,致使周围一定区域的土体发生变形。水平旋喷桩施工引起土体变形可以归结为压力膨胀和体积膨胀共同作用的问题。依托单根水平旋喷桩施工的现场实例,建立了水平旋喷桩施工引起土体变形的数值模型。将水平旋喷桩施工引起的土体变形问题简化为圆孔的膨胀问题,可以统筹考虑注浆压力和注浆流量的影响。首先需要确定注浆压力的影响半径和注浆流量引起的体积膨胀比,然后可以通过数值模型计算膨胀引起的土体变形。数值分析结果与现场实测值的对比表明,当注浆压力影响半径为成桩半径的6倍时,数值计算结果与现场实测值吻合较好。     

Acceleration of spatial motions of stars by close-binary supermassive black holes in galactic nuclei

The conditions for the acceleration of the spatial motions of stars by close-binary supermassive black holes (SMBHs) in galactic nuclei are analyzed in order to derive the velocity distribution for stars ejected from galaxies by such black holes. A close binary system consisting of two SMBHs in circular orbits was subject to a spherically symmetrical “barrage” of solar-mass stars with various initial velocities. The SMBHs were treated as point objects with Newtonian gravitational fields. Models with binary component-mass ratios of 1, 0.1, 0.01, and 0.001 were studied. The results demonstrate the possibility of accelerating neutron stars, stellar-mass black holes, and degenerate dwarfs to velocities comparable to the relative orbital velocities of the binary-SMBH components. In the stage when the binary components are merging due to the action of gravitational-wave radiation, this velocity can approach the speed of light. The most massive binary black-holes (M ? 10⁹M_⊙) can also accelerate main-sequence stars with solar or subsolar masses to such velocities.     

同向圆射流混合特性实验研究

利用声学多普勒流速仪(Acoustic Doppler Velocimetry,ADV)自动测速系统和平面激光诱导荧光(Plane Laser Induced Florescence,PLIF)系统对同向圆射流的速度场和浓度场进行了系统的研究,并与前人的工作进行了比较和讨论。时均特性测量结果表明,射流主体段下游各断面的速度和浓度横向分布是自相似的,且近似可用高斯分布来表示;随着射流向下游传播,射流中心流速逐渐衰减,在强射流区和弱射流区遵循不同的规律;紊动特性测量结果表明,下游各断面的紊动强度横向分布是自相似的。     

高压注浆加固造成铁路路基隆起的原因分析

高压旋喷法施工造成路基、地面抬升,是地基处理过程中较常见的现象。分析上海地铁9号线高压旋喷施工造成铁路路基隆起的工程实例,将路基变形过程和注水试验进行对比,得出了注浆过程满足土体注水膨胀原理;同时由于桩周产生的压力远大于土体所能承受的孔隙水压力,使破坏的土体挤压进路基底部,加大了隆起量。通过调整施工参数,可改变土体注水膨胀的本构定律与桩周压力公式中相关变量,从而减小隆起量;并提出了调整施工进度、工艺等相应的处理方案。