上奥陶统底界全球辅助层型剖面在我国的确立

国际奥陶系分会于 1 995年在美国拉斯维加斯召开的第七届国际奥陶系大会上确立了奥陶系的三统六阶划分方案后 ,笔者等即参加了确立上奥陶统底界的国际工作组。这一工作组由 S.M.Bergstrom和 S.C.Finney为主 ,先后考察了美国亚拉巴马州的 Calera剖面 ,中国的新疆柯坪大湾沟剖面 ,中国甘肃平凉官庄剖面和瑞典 Scania的 Fagelsang剖面 ,经过五年的对比研究 ,于 2 0 0 0年确立了瑞典的Fagelsang剖面为上奥陶统底界的全球层型剖面和点位 ( GSSP) ,中国的新疆大湾沟剖面和美国的亚拉巴马的 Calera剖面为上奥陶统底界的两个全球辅助层型剖面 …     

对测绘个别名词术语英文对应词的商讨

提出了对测绘辞书中个别汉语名词术语所附英文词的修改意见或建议，与测绘界同行商讨。     

平面散点集Delaunay三角剖分的一种高效方法

以平面散点集逐点插入的Delaunay三角化的方法为基础，在三角化过程中采用一定策略，将其改进成为一种简单易行而高效的方法，能够适应包括多岛、多连通域等复杂情况的各种边界，能够生成贴体的三角网，网格能够保证符合Delaunay法则。     

高层建筑中轴线点恢复测量

高层建筑物中点恢复的测量方法是在负一层测定该建筑物的中点,再引到四层楼顶,最后重新确定施工放样数据,保证该建筑物的设计要求和施工监测。     

武汉市高层建筑岩土工程问题分析

武汉市是华中地区最大的城市,改革开放以来,兴建了许多高层建筑。高层建筑尤其是超高层建筑的主要特点是高度大、重心高、基底压力大及基础埋深大等。而武汉地区的地质条件又比较复杂,就第四纪地层而言,从最新沉积的各类软土如人工填土、淤泥类土、软塑状粘性土等,到全新世(Q4)沉积的各类砂土与卵砾石,直至晚更新世(Q3)及其以前沉积的老粘土均有分布。各类土层的厚度、深度及性质均变化较大。因此武汉地区高层建筑的岩土工程问题就显得复杂与多样,在众多复杂的岩土工程问题中,本文主要分析了比较突出的基础持力层与基础类型的确定,深基坑开挖中的边坡滑移、基坑涌水、流砂、突涌以及基坑防护等。通过对这些问题的分析,从中可以得出一些规律,对今后高层建筑的兴建具有一定的指导作用。     

2-D deformation analysis of a half-space due to a long dip-slip fault at finite depth

Closed form analytical expressions of stresses and displacements at any field point due to a very long dip-slip fault of finite width buried in a homogeneous, isotropic elastic half-space, are presented. Airy stress function is used to derive the expressions of stresses and displacements which depend on the dip angle and depth of the upper edge of the fault. The effect of dip angle and depth of the upper edge of the fault on stresses and displacements is studied numerically and the results obtained are presented graphically. Contour maps for stresses and displacements are also presented. The results of Rani and Singh (1992b) and Freund and Barnett (1976) have been reproduced.     

Simulation of marine boundary layer characteristics using a 1-D PBL model over the Bay of Bengal during BOBMEX-99

The characteristic features of the marine boundary layer (MBL) over the Bay of Bengal during the southwest monsoon and the factors influencing it are investigated. The Bay of Bengal and Monsoon Experiment (BOBMEX) carried out during July–August 1999 is the first observational experiment under the Indian Climate Research Programme (ICRP). A very high-resolution data in the vertical was obtained during this experiment, which was used to study the MBL characteristics off the east coast of India in the north and south Bay of Bengal. Spells of active and suppressed convection over the Bay were observed, of which, three representative convective episodes were considered for the study. For this purpose a one-dimensional multi-level PBL model with a TKE-ε closure scheme was used. The soundings, viz., the vertical profiles of temperature, humidity, zonal and meridional component of wind, obtained onboard ORV Sagar Kanya and from coastal stations along the east coast are used for the study. The temporal evolution of turbulent kinetic energy, marine boundary layer height (MBLH), sensible and latent heat fluxes and drag coefficient of momentum are simulated for different epochs of monsoon and monsoon depressions during BOBMEX-99.The model also generates the vertical profiles of potential temperature, specific humidity, zonal and meridional wind. These simulated values compared reasonably well with the observations available from BOBMEX.     

TEM study of a special grain boundary in a synthetic K-feldspar bicrystal: Manebach Twin

 A monoclinic KAlSi₃O₈ feldspar Manebach twin boundary was synthesized by diffusion bonding and examined using high-resolution transmission electron microscopy. The sharp (001) twin boundary is straight and free of strain. The boundary width is smaller than d₀₀₁. There is no rigid body shift observed at the twin boundary, and the feldspar structure is arranged symmetrically across (001). The twin boundary structure consists of bridged tetrahedral crankshafts, which are characteristic of the feldspar lattice. The grain boundary structure is in good agreement with the geometrical model of Taylor et al. (1934). The grain boundary composition of K_1/2H_1/2AlSi₃O₈ differs from their model. Received: 13 February 2002 / Accepted: 24 December 2002 Acknowledgements We thank M. Rühle, S. Hutt, J. Mayer, A. Strecker and U. Salzberger at MPI, Stuttgart, for their support and valuable advice in preparing TEM sections of bicrystals.     

ENSO事件中纬向异常流反向与东西侧边界反射的联系

建立一个中等复杂程度的海-气耦合模式研究东、西边界反射,纬向平流项-u′(δ)(T+T′)/(δ)x在ENSO循环位相转换中的作用及东、西边界反射与纬向异常流(u′) 符号改变的关系.结果得到:u′超前Nio3区SSTA位相转变的原因是东、西边界反射造成的.Sverdrup 平衡时所产生的地转流(ur)与东、西边界反射所产生的地转流(ur)的方向在大部分时间里是相反的,同时ur与风应力强迫之间大约有9个月的滞后时间(Kelvin波从180°E出发经东边界反射产生的Rossby波到达180°E时间).在模式ENSO事件消亡过程中的某一时刻以后,边界反射产生的调整过程变为主要过程,u′主要由ur来决定,这样就造成了u′的反向先于Nio区SSTA的反向.它实际上是海洋的调整过程与风应力强迫之间滞后关系的一种反映.敏感性数值试验表明,取消东边界反射,耦合模式能够模拟ENSO循环,但其周期比控制试验的周期短一年(3年).取消-u′(δ)(T+T′)/(δ)x,耦合模式能够模拟ENSO循环,但其周期比控制试验的周期长2年(6年).     

实验速度场测量技术及对流边界层特征研究

在对流槽中对对流边界层(CBL)温度场实验研究的基础上,进一步尝试通过实验技术测量速度场并分析研究CBL中的速度场特征。在应用PIV测量技术时选用铝粉作示踪粒子。实验证明了在混合层中速度分布明显具有对流边界层热泡特性;混合层顶部的速度分布很好地反应出夹卷层的结构特征;湍流速度特征量的垂直分布合理,与野外实测结果和类似的对流槽实验结果接近;误差分析表明示踪粒子的跟随性良好,粒子速度的测量结果能真实地反应流体的运动特征,从而得证了分析结果的可靠性。