Comparisons of internal solitary wave and surface wave actions on marine structures and their responses

In this paper, a time-domain numerical model is established for computing the action of internal solitary wave on marine structures and structure motion responses. For a cylindrical structure, its side and bottom are discretized by pole and surface elements, respectively. The drag and inertial forces in the perpendicular direction of the structure are computed by the Morison equation from the pole elements, and the Froude–Krylov force in the axial direction of the structure due to internal wave motion is computed by integration of the dynamic pressure over the surface elements. The catenary theory is used to analyze the reaction force due to mooring lines, and the motion equation of the marine structure is solved by the fourth-order Runge–Kutta method in the time domain. The model is used to calculate the interaction of the internal solitary wave with a Spar platform with mooring system, and the surface wave action with the platform has also been computed by a frequency-domain boundary element method for comparison. Through the comparison based on a practical internal wave and surface wave states, it can be concluded that the internal wave force on the structure is only 9% of the one due to surface waves. However, the motion response due to the internal wave is much greater than the one due to the surface waves. It shows that the low-frequency effect of internal solitary waves is a great threat to the safety of marine structures.     

环境风垂直切变对0908号台风“莫拉克”影响的分析

利用多种卫星观测资料和NCEP/NCAR提供的风场资料等,分析环境风垂直切变对0908号台风“莫拉克”的强度、对流和降水结构的影响.结果表明:环境风垂直切变不是影响“莫拉克”强度变化的直接因素.“莫拉克”登陆前,在较强环境风垂直切变作用下,最大对流和降水区域均位于顺切变方向左侧,降水呈一阶非对称分布.“奠拉克”登陆后,...     

排山楼金矿床的蚀变特征

排山楼金矿发育有带状的蚀变晕。蚀变晕明显受韧性剪切带强带控制,从边部向中心根据蚀变强度不同可划分为:绿泥石化带,铁白云石化带和黄铁矿-绢云母化带。金矿化的程度与蚀变强弱关系密切,蚀变愈强金的品位愈高,因此,蚀变晕是寻找金矿的重要标志。     

Electron acceleration within coronal loops: A wave-particle process?

A simple model as given which aims at explaining how electrons could be accelerated within solar coronal loops due to their trapping by quasi-monochromatic whistler waves.Proceedings of the Second CESRA Workshop on Particle Acceleration and Trapping in Solar Flares, held at Aubigny-sur-Nère (France), 23–26 June, 1986.     

排山楼金矿床地质特征及金质来源

排山楼金矿床赋存于太古宙建平群东西向韧性剪切带之中。强蚀变糜棱岩即为金矿体及金矿化体。载金矿物为沿糜棱面理分布的细粒黄铁矿、动态重结晶石英集合体及铁白云石。金矿体直接受黄铁矿—黑云母化蚀变带控制。金的赋存状态以晶隙金为主,其次为少量黄铁矿包裹金。金矿化具有不同构造期的特点。金与微量元素的相关性,铅同位素及稀土元素特征都说明金来源于太古宙建平群变质岩。为同韧性剪切带型金矿床。     

STAGES AND POTENTIALITY OF WATER RESOURCES DEVELOPMENT INARID NORTHWESTERN CHINA

The processes of water resources exploitation and utilization can be divided into three stages by water resources transformation, and the history, present situation and future trend of water resources development in piedmont areas around high mountains of arid northwestern China. The three stages are: the stage of surface water development (the first stage), the stage of comprehensive development of surface and ground water (the second stage) and the stage of economical development of water resources (the third stage). The three stages link each other and show the law and processes of water resources exploitation and utilization associated with social and technological progress. The economical water policy should run through the three stages. On this point, however, the third stage differs from the others, particularly, refering to irrigated agriculture. The third stage has more progressive significance because it breaks the traditional ideas on water resources development. According to our investigation and calculation, under present conditions of water resources development, the net used water is about 160 × 10⁸ m³, accounting for 18% of the total water resources of northwestern China. The water resources have not been fully developed. If the first stage is finished, the exploitable water can be increased by 91%. After the second stage, furthermore, it can be increased by 216%. Supported by the National Natural Science Foundation of China.     

嵩山旅游资源及其开发利用

嵩山不仅是中外地质学家憧憬和瞩目的地质场所，而且还是一个旅游胜地。本文较详细地论述了嵩山的山石景观、岩溶景观、天然地质博物馆及人文景观。嵩山旅游资源类型齐全，分布集中，开发潜景远大。作者对开发嵩山旅游资源，加强资源保护等提出了对策和建议。     

The time lag of high-energy photons of Cyg X-1 in hard state

The time lag between hard and soft X-rays is an important aspect of the study of high-energy emission. Fourier cross spectrum, often used in calculating the time lag, is unable to measure statistically significant fast light variation above Fourier frequency 30 Hz from the measurements of Cyg X-1. The method of cross correlation function in time domain, developed by Li Ti-pei, can be effectively used in measuring time lags on different time scales. Using Li's method we discuss the properties of the time lag of high-energy photons of Cyg X-1 in hard state at different times. The results show that there is a significant time lap on short times scales (< 0.1 s). We confront different models of hard-state Cygnus X-1 with the observed time lag.     

利用有益微生物改善养殖生态环境的研究

研究了噬菌蛭弧菌在实验室条件下对水产养殖中常见病菌的裂解能力及噬菌蛭弧菌和光合细菌对池塘生态环境的改善作用。结果表明 ,噬菌蛭菌对嗜水气单胞菌具有裂解作用 ,噬菌蛭弧菌和光合细菌结合使用对养殖环境具有明显的改善作用。 2 5d后实验组比对照组池塘中的细菌总数少 2个数量级 ,70d后实验组比对照组池塘中的细菌总数少 3个数量级 ;2 5d后对照组COD为 6 35mg L ,使用噬菌蛭弧菌浓度为 3、5、1 0mL m3 及光合细菌皆为 5mL m3 实验组的COD分别为 4 6 7、4 1 6、4 1 8mg L ;2 5d后对照组NH3 N为 0 4 9mg L ,使用噬菌蛭弧菌浓度为 3、5、1 0mL m3 及光合细菌皆为 5mL m3 实验组的NH3 N分别为 0 36、0 33、0 32mg L ,90d后对照组NH3 N为 0 4 1mg L ,使用噬菌蛭弧菌浓度为 3、5、1 0mL m3 及光合细菌皆为 5mL m3 实验组的NH3 N分别为 0 2 7、0 2 2、0 2 1mg L ;5 5d后对照组硫化物为0 0 1 1mg L ,使用噬菌蛭弧菌浓度为 3、5、1 0mL m3 及光合细菌皆为 5mL m3 实验组的硫化物分别为0 0 1 0、0 0 0 8、0 0 0 8mg L。     

Three-dimensional Distribution of the Escape Photons of Hα Flares

A technique for obtaining a three-dimensional distribution of received pho- tons in Hα flares in the solar atmosphere is presented.It is well known that during flares hydrogen atoms in the chromosphere and photosphere are excited(even ion- ized)by the downward heating of non-thermal particles and then emit Hα photons. We trace back these Ha photons to their original layers by use of the contribution func- tion in the theory of spectral line formation,and so acquire their three-dimensional (3D)distribution.This technique is applied to the two-ribbon flare of 2002 January 20.The atmospheric models are obtained by fitting the“quasi-profiles”with the help of the generally used model atmospheres.Since the variety of the 3D images reflects the response of the atmospheric layers to the impact of energy transport,an analysis of the development of the flare is given through a comparison of the 3D images with the 2D temperature distribution.