潜孔锤冲击静压跟管钻进施工工艺的研究

工程施工钻孔中，经常遇到不稳定地层。目前，国内外针对不稳定地层的钻孔方法很多，但都有一定的局限性，且需要大型设备施工。潜孔锤冲击静压跟客钻进工艺是利用潜孔锤在套管上部的冲击和钻机自身对套管的静压，将护壁套管下入孔内的一种钻进方法。套管下入的主要动力是潜孔锤的冲击力，钻机的静压力起辅助作用。该方法可利用小型轻便钻机钻进不稳定地层，钻孔效率高，成孔质量好，设备搬迁方便。     

2002～2003年两次低温天气过程的对比分析

2002年12月下旬到2003年1月上旬，在相隔不到半个月时间内，广东省先后出现两次冷害天气过程。使用最近推出的MICAPS2．0分析系统，从环流形势、物理量梯度分布以及大气层结等方面对两次过程进行对比分析，找出引起两次过程的异同因子以及不同的“冷雨”效应。     

Fluvial gravel facies architecture of late Pleistocene age at Po Chue Tam, Lantau Island, Hong Kong: tectonic versus climatic control?

A cross-section of fluvial gravel deposits of late Pleistocene age exposed at Po Chue Tam, Lantau Island, Hong Kong contains two facies: a lower facies of planar cross-bedded gravel (Gp) and an overlying facies of clast-supported, massive gravels (Gcm). The Gp gravels include five gravel couplets. Each couplet consists of a clast-supported, coarse gravel-dominated bed and an overlying clast-supported, fine gravel-dominated bed with a discrete bounding surface. Tectonic uplift predating the last interglacial transgression produced a large amount of detritus in the source area. Excessive peak rainfall intensity resulting from enhanced seasonality of monsoonal precipitation in the following glacial period triggered catastrophic floods, which transported mature detritus in large quantities into a fault-controlled piedmont basin. The Gp gravels were deposited by pulsating flood flows. In relation to kinematic waves of particles, bedload sediment was longitudinally sorted and segregated into a train of gravel sheets. They draped over each other and accreted laterally due to expansion of flow, producing planar cross stratifications that are characteristic of recurrent, couplet-style coarse/fine cross beds. In contrast, Gcm gravels were laid down as a single, nearly horizontal bed by a catastrophic flood that was not subject to flow pulsation.     

焉耆盆地一次暴雪天气的分析

2000年2月21-22日焉耆盆地出现了大到暴雪过程，本文重要分析了此次天气过程的地面冷锋、水汽条件、稳定度和地面要素变化等，得到了一些大雪天气成因的结论。     

不稳定地温场的有限差分模拟

对矿井地温场的研究具有多方面的意义.本文采用有限差分法对不稳定地温场进行了研究,根据数学模型建立起差分方程,编制了计算程序,并通过一个实例分析了岩床侵入煤系地层时的温度变化规律.     

两种垂直分层方法对GPS水汽层析结果的影响

利用北京房山地区9个全球定位系统测站组成的实验站网,研究GPS水汽层析网格的划分方法,采取垂直均匀和垂直非均匀两种分层方法,分析GPS层析网格垂直分层对水汽层析结果的影响。结果表明：均匀和非均匀垂直分层方法得到的GPS水汽层析结果是可靠的,均可以与探空水汽结果进行比较。但垂直非均匀分层更符合大气水汽的实际分布特征,层析解算精度更高,尤其对测站高度差较小的GPS站网,尽量选择垂直非均匀分层方法。垂直均匀和垂直非均匀分层方法均可以为北京地区GPS层析网格垂直划分提供参考。     

Stratification of phosphorus in the atmosphere of the chemically peculiar B-type star HR 1512

A number of empirical relationships are shown to indicate an increase in the abundance of phosphorus logε(P) with height in the atmosphere of HR 1512. These include: (a) a correlation of logε(P) with the observed equivalent width W_obs of PII lines; (b) a correlation of logε(P) with the wavelength of the lines; (c) a systematic divergence in the values of logε(P) for lines with different excitation potentials E_l; in particular, lines with lower E_l correspond on the average to higher abundances logε(P); and, (d) a distinct dependence of logε(P) on the average geometrical height of formation, H_f. In addition, assuming that logε(P) is constant in the star's atmosphere leads to a systematic discrepancy between the theoretical equivalent widths W_th and the observed values W_obs. By a trial and error method we have found a distribution of the phosphorus abundance logε(P) with height H such that the systematic difference between W_th and W_obs vanishes. It turned out, however, that a simpler, step distribution of logε(P) yields equally good agreement between W_th and W_obs. Although the solution is nonunique, both distributions have some features in common, specifically: (1) a sharp rise in logε(P) occurs in the same range of heights H corresponding to optical thicknesses τ ₅₀₀₀ ≈ 10⁻²–10⁻³, i.e., stratification of phosphorus takes place in rather high layers of the atmosphere of HR 1512, and (2) the upper bound, logε _up(P) = 8.9, is the same in both cases, so that in the region of the rise, logε(P) increases by 3.4 dex. A comparison with available data for HgMn, Am, and Ap type stars shows that similar sharp changes in the abundances logε of several elements occur in other CP stars, at the same optical depths or in even higher layers of their atmospheres. __________ Translated from Astrofizika, Vol. 51, No. 2, pp. 239–253 (May 2008).     

三峡库区危岩稳定性断裂力学计算方法

危岩崩塌实际是危岩主控结构面断裂扩展问题。基于主控结构面的断裂力学模型提出了危岩断裂稳定性判定方法,建立了以联合应力强度因子为指标的危岩稳定系数,推导得出危岩主控结构面尖端受力分布形式及计算表达式,提出了危岩主控结构面尖端断裂力学模型,推导得出主控结构面尖端联合应力强度因子计算公式。重庆万州首立山危岩断裂稳定性计算结果表明,计算结果与现场情况较吻合,采用文中的断裂稳定性计算方法比现有的地质灾害防治工程设计规范更加安全、客观、实际。     

赤道大洋定常风生环流的理论模型

为了模拟以南、北赤道流、赤道逆流和赤道潜流为特征的赤道流系,从长时间平均的线性化的海水运动方程出发,考虑海水层化、保留经向摩擦作用,利用赤道太平洋中部海区经向流通量不随纬度变化的量阶估计,得到海水密度跃层对赤道风场的响应,即跃层深度的分布规律,然后应用我们已构建的改进Fourier方法求解(由于地转口效应所引入的)变系数的海水运动方程,得到适用于中部赤道太平洋的级数形式的三维流场解。