南京玄武湖水底交通隧道工程与环境效应分析

南京玄武湖隧道,既在城市中心,又在水下,是脆弱环境下典型的地质工程。影响水下隧道施工的不权有环境工程地质条件,还有城市环境约束因素;另外,隧道施工会对城市环境产生不良影响。作者对上述问题作了具体分析,并用系统工程的思想对隧道出口及施工方案的选择进行了初步评价。     

Topographically forced three-wave quasi-esonant and non-resonant interactions among barotropic rossby waves on an infinnite beta-plane

In this paper, we first apply the assumption h = εh′ of topographic variation (h is the nondimensional topographic height and is a small parameter) to obtain nonlinear equations describing three-wave quasi-resonant and non-resonant interactions among Rossby waves for zonal wavenumbers 1—3 over a wavenumber-two bottom topography (WTBT). Some numerical calculations are made with the fourt-order Rung-Kutta Scheme. It is found that for the case without topographic forcing, the period of three-wave quasi-resonance (TWQR) is found to be independent of the zonal basic westerly wind, but dependent on the meridional wavenumber and the initial amplitudes. For the fixed initial data, when the frequency mismatch is smaller and the meridional wavelength is moderate, its period will belong to the 30–60-day period band. However, when the wavenumber-two topography is included, the periods of the forced quasi-resonant Rossby waves are also found to be strongly dependent on the setting of the zonal basic westerly wind. Under the same conditions, only when the zonal basic westerly wind reaches a moderate extent, intraseasonal oscillations in the 30–60-day period band can be found for zonal wavenumbers 1–3. On the other hand, if three Rossby waves considered have the same meridional wavenumber, three-wave non-resonant interaction over a WTBT can occur in this case. When the WTBT vanishes, the amplitudes of these Rossby waves are conserved. But in the presence of a WTBT, the three Rossby waves oscillate with the identical period. The period, over a moderate range of the zonal basic westerly wind, is in the intraseasonal, 30–60-Day range.     

准四年周期的北半球夏季遥相关与东亚夏季风环流的相互关系

利用ＮＭＣ的２００ｈＰａ和８５０ｈＰａ风场资料研究了北半球夏季遥相关和东亚夏季风异常环流在准４年时间尺度上的相互关系。研究发现当北半球夏季出现积雪强迫型遥相关时,东亚－西太平洋地区既存在异常纬向环流,也存在异常经向环流;而当出现东亚太平洋型遥相关时,东亚－西太平洋地区以异常纬向环流为主。分析还发现源于北太平洋的异常涡旋在向南传播的过程中,先取西南路径,在到达菲律宾东部以后折向东南。     

河西走廊东部甜菜含糖量预测模式

运用灰色系统理论中的关联度方法,分析影响武威黄羊镇糖厂含糖量的气象因素,并建立了不含导数项的线性静态模式。经残差修正后,预测精度达９８．１１％。     

中国地区大气气溶胶辐射强迫及区域气候效应的数值模拟

利用太阳直接辐射日总量和日照时数等多年观测资料,反演了中国地区大气气溶胶0.75 μm光学厚度的年、月平均值,分析了我国大气气溶胶状况的时空分布特征。据此,在中国区域气候模式中考虑气溶胶的辐射影响,模拟中国地区气溶胶直接辐射强迫的大小及气候响应的季节变化特征。计算结果表明: 我国大气气溶胶光学厚度多年平均分布状况是以四川盆地为大值中心向四周减少;长江中下游武汉附近和南疆盆地为另两个大值中心;青藏高原为气溶胶低值区;我国绝大部分地区春季气溶胶光学厚度值最大,各地气溶胶光学厚度最小值出现的季节则有所不同。气溶胶辐射强迫介于-5.3～-13 W/m2之间;辐射强迫具有春、夏季大,秋、冬季小,冬季南方偏大,夏季北方偏大的特征。气溶胶辐射强迫的分布与其光学厚度的分布基本一致。由于气溶胶的影响,中国大陆地区地面气温均有所下降,四川盆地到长江中下游地区以及青藏高原北侧到河套地区降温最为明显,分别可达-0.4℃和-0.5℃。气候响应具有明显的季节特征。地面气温的变化除与辐射强迫的大小有关外,还受大气环流的影响。     

Hydrodynamic effect of the regulation project of Yangtze River deepwater channel downstream of Nanjing

A two-dimensional flow numerical model of the tidal reaches, which total length is more than 700 km, is established from Datong to the Yangtze River estuary. The tidal levels, velocities, diversion ratios and dynamic axes before and after the separate regulation of each reach and combined regulation of all reaches are obtained. The comparative analysis shows that the regulation project of a separate reach basically has no impact on velocity distributions and variations of diversion ratios of upper and lower reaches, the variations of dynamic axes are only within the local scope of the project. The regulation project of a separate reach also has less impact on the water level in the lower adjacent reaches, but will make the water levels in the upper reaches rise. After the implementation of the regulation projects for all reaches, the rise of water level in the upstream reaches will have a cumulative impact.     

Seven-frequency VLBI Observations of the GHz-Peaked-Spectrum Source OQ 208

We present quasi-simultaneous VLBI images of the GHz-Peaked-Spectrum radio source OQ 208 obtained with the Very Long Baseline Array at 1.4,1.7,2.3,5.0,8.4,15.4GHz and the European VLBI Network at 6.7 GHz.The low frequency(1.4,1.7 and 2.3GHz)ob- servations reveal a weak and extended steep-spectrum component at about 30mas away at position angle-110°,which may be a remnant emission.The radio structure of OQ 208 con- sists of two mini-lobes at 5.0,6.7,8.4 and 15.4 GHz.Our spectral analysis further confirms that the southwest lobe undergoes free-free absorption and finds that the free-free absorption is stronger in the inner region.By fitting the 8.4 GHz images from 1994 to 2005,we obtain a separation speed of 0.031±0.006 mas yr~(-1)between the two mini-lobes.This indicates a jet proper motion of 0.105±0.020 c and a kinematic age of 219±42 yr for the radio source.     

一种可能的地震成因模型

提出了一种地震成因模型。认为不仅水库地震、矿震等是被人类工程活动诱发的，其它地震也很可能有诱发因素起作用。这种作用不仅仅是触发了地震，地震的孕育很可能也与其有关。诱发因素包括人类工程活动、地外天体的特殊位置、地球自转角速度的变化、气象异常等。这些因素对地壳产生了附加垂直力，后者引起局部地层弯曲，进而导致应力集中、构造应力作用方式的改变乃至地震发生。     

Stellar and HI Mass Functions Predicted by a Simple Preheating Galaxy Formation Model

According to the new preheating mechanism of galaxy formation suggested by Mo et al., we construct a simple model of formation of disk galaxies within the current paradigm of galaxy formation. It incorporates preheating, gas cooling, bulge formation and star for-mation. The predicted stellar and HI mass functions of galaxies are discussed and compared with the observations. It is found that our model can roughly match both the observed galaxy luminosity function and the observed HI-mass function.     

Numerical modeling of secondary migration and its applications to Chang-6 Member of Yanchang Formation (Upper Triassic), Longdong area,Ordos Basin,China

Mathematic modeling, established on the basis of physical experiments, is becoming an increasingly important tool in oil and gas migration studies. This technique is based on the observation that hydrocarbon migration tends to take relative narrow pathways. A mathematical model of hydrocarbon migration and accumulation is constructed using the percolation theory. It is then calibrated using physical experimental results, and is tested under a variety of conditions, to understand the applicability of the model in different migration cases. Through modeling, dynamic conditions of large-scale migration pathways within homogeneous formations can be evaluated. Basin-scale hydrocarbon migration pathways and their characteristics are analyzed during the model application to the Chang-8 Member of the Triassic Yanchang Formation in Longdong area of Ordos Basin. In heterogeneous formations, spatial changes in fluid potential determine the direction of secondary migration, and heterogeneity controls the characteristics and geometry of secondary migration pathways.