北京房山世界地质公园岩溶景观特色

北京房山世界地质公园是以岩溶洞穴景观和峰丛地貌景观为主题的地质公园。大石河流域发育中奥陶统马家沟组石灰岩,自上而下,依次发育鸡毛洞、银狐洞、石花洞和孔水洞,由一条地下暗河将其连为一个洞系,其水源补给点在大石河上游,排泄点为孔水洞。周口店猿人遗址属于中奥陶统马家沟组岩溶洞穴。拒马河流域发育中元古界雾速山组白云岩,岩溶洞穴包括云水洞、仙栖洞、龙仙宫和三清洞,均属唐县期夷平面时期的产物。拒马河流域地层平缓的中元古界雾速山组峰丛地貌区东从张坊起,西至大沙地,南临笔架山,北抵石人峰,流域面积395km~2,其中碳酸盐岩岩石面积占360km~2,山体上部的岩石被溶解,形成峰丛地貌景观。     

显式完全平方守恒差分格式在近岸海流数值模拟中的应用

用显式完全平方守恒差分格式及其改进分解算法对南海月平均流和海面起伏进行了数值模拟，与隐式完全平方守恒差分格式相比，计算时间可省３—５倍，具有良好的时间效益，而且，其计算效果不比隐式完全平方守恒差分格式差。因此，显式完全平方守恒差分格式及其改进分解算法具有良好的实用价值。     

新型珊瑚海水混凝土力学性能试验研究

为了解决全珊瑚海水混凝土(coral aggregate seawater concrete,简称CASC)的脆性问题,采用碱式硫酸镁水泥(basic magnesium sulfate cement,简称BMSC)为胶凝材料和剑麻纤维为增韧材料制备了一种新型全珊瑚海水混凝土(NCASC),系统测定了基本力学性能,并与普通硅酸盐水泥制备的CASC、碱式硫酸镁水泥砂石混凝土(basic magnesium sulfate cement concrete,简称BMSCC)、普通砂石混凝土(ordinary portland cement concrete,简称OPC)以及普通轻骨料混凝土(lightweight aggregate concrete,简称LAC)的力学性能进行对比。结果表明:立方体抗压强度(f_(cu),m)在15~35 MPa范围内的NCASC的轴心抗压强度(f_c,m)、劈裂抗拉强度(f_(sp),m)与f_(cu),m之间具有较显著的线性关系;对于f_(cu),m为15~35 MPa的混凝土,相同强度NCASC的f_c,m高于OPC、LAC及BMSCC,其f_c,m与f_(cu),m比值最大,大致在0.85~0.96之间,NCASC的f_(sp),m比OPC和LAC高,但比BMSCC低,且随着强度的提高,OPC与NCASC的f_(sp),m间的差距在增大,而LAC和BMSCC与NCASC的f_(sp),m间的差距在缩小;在强度等级C15~C55的范围中,NCASC和CASC的f_(sp),m、f_c,m与f_(cu),m之间的关系基本可以采用相同的线性回归方程来描述,利用这两个回归线性方程得到对应于标准强度等级的CASC和NCASC的f_(sp),m和f_c,m数据,为CASC力学性能研究与结构设计提供参考依据。     

A New Retracking Technique for Brown Peaky Altimetric Waveforms

A new Brown-Peaky (BP) retracker has been developed for peaky waveforms that usually appear within ～10 km to the coastline. The main feature of the BP is that it fits peaky waveforms using the Brown model without introducing a peak function. The retracking strategy first detects the peak location and width of a waveform using an adaptive peak detection method, and then estimates retracking parameters using a weighted least squares (WLS) estimator. The WLS assigns a downsized weight to corrupted waveform gates, but an equal weight to other normal waveform gates. The BP retracker has been applied to 4-year Jason-1 waveform (2002–2006) in two Australian coastal zones. The results retracked by BP, MLE4 and ALES retrackers have been validated against tide-gauge observations located at Burnie, Lorne and Broome. The comparison results show that three retrackers have similar performance over open oceans with the correlation coefficient (～0.7) and RMSE (～13 cm) between altimetric and tide-gauge sea levels for distance >7 km offshore. The main improvement of BP retracker occurs for distance ≤7 km to the coastline, where validation results indicate that data retracked by BP are more accurate (15–21 cm) than those by ALES (16–24 cm) and MLE4 (19–37 cm).     

Tropical Cyclone Genesis Potential Index for Bay of Bengal During Peak Post-Monsoon (October-November) Season Including Atmosphere-Ocean Parameters

Several studies on tropical cyclone genesis potential index (GPI) mainly using atmospheric parameters (relative/absolute vorticity, relative humidity, vertical wind shear, potential instability, vertical velocity etc.) have been reported earlier. Though the ocean plays a vital role in the genesis and intensification of cyclones, no ocean parameter has been included in most of the studies. In this study, we have made an attempt to develop a new GPI for Bay of Bengal during peak post-monsoon (October-November) season including upper ocean heat content (UOHC) using the data for the period 1995–2015. It is found that the new GPI is better correlated with the total number of depressions, cyclones and severe cyclones (TNDC) compared with the existing GPI which was developed for the north Indian Ocean and presently used by India Meteorological Department (IMD), New Delhi. The correlation has significantly enhanced (r=0.86:significant at >99% level) by using the first differences [year(0) –year(?1)] of the time series data. Since, the new GPI which considers atmosphere and ocean (UOHC) parameters, it appears to be more suitable for Bay of Bengal during the peak post-monsoon season.     

南海IODP 349航次基底玄武岩中碳酸盐岩脉的岩石学特征*

国际大洋发现计划(International Ocean Discovery Program, IODP)349航次在南海东部次海盆和西南次海盆残留扩张脊附近的U1431和U1433站位首次钻取基底玄武岩, 通过对16块基底玄武岩内的碳酸盐岩脉薄片镜下观察以及激光拉曼光谱分析, 揭示碳酸盐矿物为方解石和文石, 为典型的洋壳低温热液蚀变次生矿物。U1431站位碳酸盐岩脉为独立的方解石脉、文石脉交替出现; 而U1433站位则存在方解石脉、文石脉和方解石-文石共生脉三种情况。此外, U1431站位在基底~42.1m处出现了平行的方解石脉和文石脉, 揭示U1431存在不同来源热液的多期活动, 即可能存在多次或多阶段不同的热液注入。U1431和U1433站位的碳酸岩脉中, 文石的矿物集合体形状基本一致, 呈块状、纤维状和放射纤维状; 而方解石存在差异, U1431的方解石以斑块状、块状、粒状和纤维状出现, 而U1433的方解石仅出现块状。U1431站位的碳酸盐岩脉的丰度明显高于U1433站位。这些均揭示U1431站位的低温热液活动强, 而U1433站位则相对弱。两个站位的热液活动不同很可能是由于区域地质环境的差异造成——U1431附近的巨大海山为其提供了热液补给, 而U1433远离热液的补给/渗漏点。     

Improvement in the calculation of anti-Stokes energy transfer and experimental justification based on Er0.01YbxY1 - 0.01 - xVO4 crystal

The improvement on the calculation of anti-Stokes energy transfer rate is studied in the present work. The additional proportion coefficient between Stokes and anti-Stokes light intensities of quantum Raman scattering theory as compared with the classical Raman theory is introduced to successfully describe the anti-Stokes energy transfer. The theoretical formula for the improvement on the calculation of anti-Stokes energy transfer rate is derived for the first time in this study. The correctness of introducing coefficient exp{ΔE / kT} from well-known Raman scatter theory is demonstrated also. Moreover, the experimental lifetime measurement in Er_0.01Yb_xY_{1 - 0.01 - x}VO₄ crystal is performed to justify the validity of our important improvement in the original phonon-assisted energy transfer theory for the first time.     

boldmath Investigation of inter-molecular hydrogen bonding in the binary mixture (acetone + water) by concentration dependent Raman study and ab initio calculations

This paper reports that vibrational spectroscopic analysis on hydrogen-bonding between acetone and water comprises both experimental Raman spectra and ab initio calculations on structures of various acetone/water complexes with changing water concentrations. The optimised geometries and wavenumbers of the neat acetone molecule and its complexes are calculated by using ab initio method at the MP2 level with 6-311+G(d,p) basis set. Changes in wavenumber position and linewidth (fullwidth at half maximum) have been explained for neat as well as binary mixtures with different mole fractions of the reference system, acetone, in terms of intermolecular hydrogen bonding. The combination of experimental Raman data with ab initio calculation leads to a better knowledge of the concentration dependent changes in the spectral features in terms of hydrogen bonding.     

Temporal electronic structure of non-resonant Raman excited virtual state of P-nitroaniline by 514 nm excitation via bond polarisabilities

We have studied the temporal bond polarisabilities of para-nitroaniline from the Raman intensities by the algorithm proposed by Wu et al. in 1987 (Tian B, Wu G, Liu G 1987 J. Chem. Phys. 87 7300). The bond polarisabilities provide much information concerning the electronic structure of the non-resonant Raman excited virtual state. At the initial moment by the 514.5 nm excitation, the tendency of the excited electrons (mapped out by the bond polarisabilities) is to spread to the molecular periphery, and the electronic structure of the Raman virtual state is close to the pseudo-quinonoidic state. When the final stage of relaxation is approached, the bond polarisabilities of those peripheral bonds relax faster than those closer to the molecular core, the phenyl ring. The molecule is in the benzenoidic form as demonstrated by the bond polarisabilities after relaxation.     

Implementation of baroclinic terms in a three-dimensional hydrodynamic model and its application to Anzali Port, Iran

Baroclinic terms have been implemented in a three-dimensional fully hydrodynamic model developed by Badiei et al. [2008. A three-dimensional non-hydrostatic boundary fitted model for free surface flows. International Journal for Numerical Methods in Fluids, 56(6), 607-627] modifying its momentum equations to account for density gradients and utilizing the scalar (salinity, temperature, etc.) conservation equation (SCE) and a state equation for the calculation of density. In the solution of advection-diffusion terms of the governing Navier-Stokes equations (NSE) and SCE, a symmetric splitting method was applied to ensure the long-term stability of simulations. Correction terms proposed by Ruddic et al. (1995) were applied to SCE to ensure the conservation of the scalar quantity. In the presence of baroclinic terms, the zero gradient pressure in the vertical direction in the vicinity of surface and bottom boundaries assumed by Badiei et al. [2008. A three-dimensional non-hydrostatic boundary fitted model for free surface flows. International Journal for Numerical Methods in Fluids, 56(6), 607-627] created spurious currents. This problem was solved by assuming a hydrostatic pressure variation at those boundaries. The ability of extended model was validated by comparing its results with an experimental test case. The simulation of hydrodynamic and salt intrusion at Anzali Port located at the southern coasts of Caspian Sea in Iran was carried out by the model with both barotropic and baroclinic modes. The simulated results with baroclinic mode show a better agreement with measured data as compared to the results of barotropic mode that clearly demonstrate the significance of baroclinic terms in the simulation of cyclic intrusion of salt wedge into the Port Basin.