洛阳市供水前景预测及对策探讨

洛阳市地下水资源量丰质优，远期供水前景较为乐观。然而，由地下水开采引起的环境水文地质问题仍属客观存在。本文在供水前景预测的基础上，提出了五项对策，对城市远期供水规划具借鉴意义。     

The characteristics of motion of thin magnetic tubes

Starting from the equations of motion of a thin magnetic tube, the characteristic curves and velocities and compatibility relations are derived as basis for investigating its motion and for correctly formulating the problem of stationary solution. It is shown that the characteristic velocity of transverse waves is related to the Alfvén Mach number of the flow in the tube. When the flow velocity exceeds the critical value for the Kelvin-Helmholtz instability, transverse waves cease to exist.     

Deepwater Ventilation and Stratification in the Neogene South China Sea

Combined data of physical property, benthic foraminifera, and stable isotopes from ODP Sites 1148, 1146, and 1143 are used to discuss deep water evolution in the South China Sea (SCS) since the Early Miocene. The results indicate that 3 lithostratigraphic units, respectively corresponding to 21-17 Ma, 15-10 Ma, and 10-5 Ma with positive red parameter (a*) marking the red brown sediment color represent 3 periods of deep water ventilation. The first 2 periods show a closer link to contemporary production of the Antarctic Bottom Water (AABW) and Northern Component Water (NCW), indicating a free connection of deep waters between the SCS and the open ocean before 10 Ma. After 10 Ma, red parameter dropped but stayed higher than the modern value (a*=0), the CaCO3 percentage difference between Site 1148 from a lower deepwater setting and Site 1146 from an upper deepwater setting enlarged significantly, and benthic species which prefer oxygen-rich bottom conditions dramatically decreased. Coupled with a major negative excursion of benthic δ13C at ~10 Ma, these parameters may denote a weakening in the control of the SCS deep water by the open ocean. Probably they mark the birth of a local deep water due to shallow waterways or rise of sill depths during the course of sea basin closing from south to east by the west-moving Philippine Arc after the end of SCS seafloor spreading at 16-15 Ma. However, it took another 5 Ma before the dissolved oxygen approached close to the modern level. Although the oxygen level continued to stabilize, several Pacific Bottom Water (PBW) and Pacific Deep Water (PDW) marker species rapidly increased since ~6 Ma, followed by a dramatic escalation in planktonic fragmentation which indicates high dissolution especially after ~5 Ma. The period of 5-3 Ma saw the strongest stratified deepwater in the then SCS, as indicated by up to 40% CaCO3 difference between Sites 1148 and 1146. Apart from a strengthening PDW as a result of global cooling and ice cap buildup on northern high latitudes, a deepening sea basin due to stronger subduction eastward may also have triggered the influx of more corrosive waters from the deep western Pacific. Since 3 Ma, the evolution of the SCS deep water entered a modern phase, as characterized by relative stable 10% CaCO3 difference between the two sites and increase in infaunal benthic species which prefer a low oxygenated environment. Thesubsequent reduction of PBW and PDW marker species at about 1.2 Ma and 0.9 Ma and another significant negative excursion of benthic δ13C to a Neogene minimum at ~0.9 Ma together convey a clear message that the PBW largely disappeared and the PDW considerably weakened in the Mid-Pleistocene SCS. Therefore, the true modern mode SCS deep water started to form only during the "Mid-Pleistocene climatic transition" probably due to the rise of sill depths under the Bashi Strait.     

An Adaptive Supervised Nonlinear Feature Extraction for Hyperspectral Imagery Classification

In this paper, an improved version of locally linear Embedding is proposed. In the proposed method, spectral correlation angle is invited to describe the distance between data points, which is expected to fit the hyperspectral image (HSI). The neighborhood graph of the data points is constructed based on supervised method. Different from traditional supervised feature extraction methods, the weight factors, which are used to control the transform, are adaptively achieved. In this way, the input arguments of original algorithm are not increased. To justify the effectiveness of the proposed method, experiments are conducted on two HSIs. Results show that the proposed method can improve the separability of HSI especially in low dimensions.     

顾及钟差随机项的GPS卫星钟差预报

针对卫星钟差呈趋势项和随机项变化的特点,提出了基于GM(1,1)与自回归求和移动平均的组合预报模型。该模型首先采用GM(1,1)模型预报钟差的趋势项部分,然后利用ARIMA模型对GM(1,1)的模型残差序列进行建模和预报,最后将GM(1,1)和ARIMA模型的预报结果对应相加即得到钟差的最终预报值。此外,采用IGS公布的精密卫星钟差进行预报试验,通过与卫星钟差预报中常用的二次多项式模型和修正指数曲线法模型预报结果的对比分析,结果表明:该方法可以对GPS卫星钟差进行高精度的中短期预报。用12 h钟差建模时,预报未来6、12、24和48 h的平均预报精度分别为0.71、1.17、1.93和4.38 ns,相比于二次多项式模型的平均预报精度分别提高了29.70%、43.75%、67.62%和76.21%;相比于修正指数曲线法模型的平均预报精度分别提高了18.39%、33.90%、61.40%和70.49%。     

星载激光光斑影像质心自动提取方法

激光光斑影像的质心提取是卫星激光测高数据处理中的重要环节,对于获得精确的激光指向角有重要的意义。本文总结了灰度重心法、高斯拟合法以及椭圆拟合法3种常用的质心提取方法,在比较其优缺点之后结合高斯曲面拟合法和椭圆拟合法,提出了一种基于高斯阈值的椭圆拟合方法,针对仿真数据进行试验,有较好的精度结果。采用GLAS（geoscience laser altimeter system）的实际激光光斑影像LPA（laser profile array）数据进行试验,发现LPA光斑质心位置变化周期约为1.5 h,幅度最大可达2~3个像素,对应激光指向角变化约9",说明在轨监视激光质心位置变化对于提高激光指向角测量精度非常必要。相关结论可为后续国产卫星激光测高仪足印影像处理提供参考。     

灰色-时序组合模型在建筑沉降预测中的应用

以实际地面沉降数据为基础,分别用灰色模型、时间序列模型对实测数据进行预测,然后按照一定方法对灰色模型、时间序列模型赋予合理权值,建立了灰色-时序组合模型~([1])。预测结果表明,组合模型的预测精度更为准确、可靠,说明该组合模型具有一定的可适用性。     

Investigating the effect of degree of compaction,initial water content,and electric field intensity on electrokinetic remediation of an artificially Cu- and Pb-contaminated loess

Acta Geotechnica - Given copper and lead mine enrichment and the high yield of North-Western China, the metallurgical industry attains prosperity. Metallurgical industrial waste which contains...     

Gas migration behavior in saturated bentonite under flexible conditions with consideration of temperature effects

Acta Geotechnica - Investigation of thermal effects on gas migration behavior in saturated bentonite materials is of great significance for the assessment of long-term safety and performance...