万山水域温盐分析：海湾扇贝养殖环境可行性研究

对初步建成的《养殖水域温盐信息系统》进行试验开发，分析了海湾扇贝南移至万山水域养成的可行性。根据万山湾18a每日的温盐信息，通过平均值、距平值、极限值等多项统计特性的分析，认为珠江口水域只有10月至翌年4月基本具备养成海湾扇贝的温盐自然条件，盐度20～35；温度18～28℃。而每年6～8月该水域都会受高温、低盐的袭击，盐度极端低值曾出现2．39、3．06、4．80等，在这样的盐度条件下，会导致海湾扇贝养殖成体全部死亡。因此，本着因地制宜的方针，作者认为该水域不宜发展海湾扇贝养殖。     

四川核电站气象服务系统初探

本文在分析四川核电站建设选址落户南充．其核电站选址、建设和核能发电对开展核电气象监测手段和内容、拓展气象服务领域、核电与气象关系等方面进行了需求目的分析，提出四川核电站气象监测、服务、应用气象研究的工作思路和方案，为四川核电建设和可持续发展提供气象服务。     

Impact Assessment of Urban Meteorology and the Atmospheric Environment Using Urban Sub-Domain Planning

For the purpose of (1) investigating the relationship between urban planning and the atmospheric environment, and (2) improving the atmospheric environment through rational and scientific planning, an urban sub-domain scale model is developed in the form of a three-dimensional non-hydrostatic model with k – ɛ closure. The distribution and azimuth of buildings, the screening of shortwave radiation by buildings, and the underlying surface type as characteristics of the urban environment are included, the ground temperature is calculated using the force-restore method, and the concentration equation is solved simultaneously. The model is evaluated using special field observations and wind-tunnel experiment data, showing that model results meet the observational and experimental data generally well. Based on the model, an index system and evaluation method is set up to assess the impact of urban meteorology and the atmospheric environment using urban sub-domain planning. As an example, two layouts of a specific sub-domain in Beijing are assessed. The impact assessment system of urban meteorology and the atmospheric environment using urban sub-domain planning, which includes the urban sub-domain scale numerical model, index system and evaluation method, provides an effective approach to improve the atmospheric environment through rational and scientific planning.     

福州华林井数字化水位观测数据的对比分析

通过对福州华林井数字化水位观测系统产出的两套数据的对比分析 ,我们发现公用数采采集的水位整点值略高于LN - 3型数字水位自身采集打印的水位整点值 ,但两者的水位整点值曲线图的形态是完全一致的。因此 ,我们认为公用数采产出的数据可以完全取代LN - 3水位仪自身打印的数据 ,这对“十五”期间完成数字化改造之后利用数字化观测资料进行分析提供了依据。     

The westerly anomalies over the tropical pacific and their dynamical effect on the enso cycles during 1980–1994

In this paper, the zonal wind anomalies in the lower troposphere over the tropical Pacific during 1980–1994 are analyzed by using the observed data. The results show that during the formation of the 1982/83, 1986/87 and 1991 / 92 ENSO events, there were the larger westerly anomalies in the lower troposphere over the equatorial Pacific. Moreover, it is explained by using the correlation analyses that the westerly anomalies over the equatorial Pacific could cause the warm episodes of the equatorial central and eastern Pacific. A simple air-sea coupled model is used to discuss theoretically the dynamical effect of the observed westerly anomalies of wind stress near the sea surface of the equatorial Pacific on the ENSO cycle occurred in the period of 1981–1983. It is shown by using the theoretical calculations of the equatorial oceanic Kelvin wave and Rossby waves responding to the forcing of the observed anomalies of zonal wind stress near the sea surface of the equatorial Pacific that the westerly anomalies of wind stress near the sea surface of the equatorial Pacific make significant dynamical effect on the ENSO cycles occurred in the period of 1982–1983.     

佛山市暴雨过程的逐时雨量分布特征初探

通过历年暴雨逐时雨量分布特征的分析，摸索暴雨过程的演变规律，从而提高对暴雨规律及中尺度系统的认识，拓宽暴雨研究新领域；同时对排水工程的设计和暴雨预警信号的发布提供了重要的参考依据。     

水流作用下斜桩局部冲刷及流场变化试验研究

为研究水流作用下斜桩周围局部冲刷特性及流场变化并掌握斜桩同垂直桩的差异,本研究在不同流速条件下开展了包含反斜桩、垂直桩、正斜桩等多种工况的水槽试验,测量分析了斜桩的冲刷历时曲线、床面形态、沿程流速分布、最大冲刷深度等数据.结果表明:清水条件下斜桩周围局部冲刷坑及桩后沙丘尺度明显减小;斜桩桩前最大冲刷深度随倾角的增加而逐...     

Dynamic force control with hydraulic actuators using added compliance and displacement compensation

A new approach to dynamic force control of mechanical systems, applicable in particular to frame structures, over frequency ranges spanning their resonant frequencies is presented. This approach is implemented using added compliance and displacement compensation. Hydraulic actuators are inherently velocity sources, that is, an electrical signal regulates their velocity response. Such systems are therefore by nature high‐impedance (mechanically stiff) systems. In contrast, for force control, a force source is required. Such a system logically would have to be a low‐impedance (mechanically compliant) system. This is achieved by intentionally introducing a flexible mechanism between the actuator and the structure to be excited. In addition, in order to obtain force control over frequencies spanning the structure's resonant frequency, a displacement compensation feedback loop is needed. The actuator itself operates in closed‐loop displacement control. The theoretical motivation, as well as the laboratory implementation of the above approach is discussed along with experimental results. Having achieved a means of dynamic force control, it can be applied to various experimental seismic simulation techniques such as the effective force method and the real‐time dynamic hybrid testing method. Copyright © 2008 John Wiley & Sons, Ltd.     

流体迁移和海底地形与天然气水合物的形成

使用重力取样器、渔网、深潜器等手段,已经在海底及以下浅表层的区域采获天然气水合物样品,但关于浅表层水合物的发育机制、分布规律、与海底地形的关系等问题还缺乏基本认识。根据2006年鄂霍次克海天然气水合物调查航次的调查数据,发现萨哈林东北陆坡区,特别是中、下陆坡区发育大量海底凸起。这些凸起一般呈不对称的丘形,宽几百米,高几十米。与海底沙波、沙脊不同,海底凸起为孤立海底地形,在南北方向上并不连续。海底剖面仪结果清楚地显示古陆坡凸起的发育。现今海底陆坡凸起的幅度普遍地要小于古陆坡凸起的幅度,个别地方古今陆坡凸起的形态有所变化,但大部分古、今陆坡凸起是一一对应的,基本形态没有根本变化。在萨哈林陆坡地区存在两个方向的挤压应力场,分别是由德鲁根盆地向萨哈林陆坡方向的挤压应力场和萨哈林陆坡沿萨哈林走滑断裂向南的挤压应力场,海底陆坡凸起是这两大应力场复合作用的结果。浊反射区中的游离气是底辟构造中的超高压多相物质向上迁移形成的,浊反射区上方对应的海底凸起应该是宏观构造挤压和局部底辟发育叠合的结果,浊反射区上方的海底凸起,在形态等方面应该和其他仅由挤压构造原因形成的凸起有所区别,比如顶部发育裂口等。在底辟构造中,由于游离气体的向上迁移,在整个水合物稳定域中从下到上,直至海底都可能形成水合物。     

A two-dimensional numerical wave flume based on SA-MPLS method

A spatially adaptive(SA) two-dimensional(2-D) numerical wave flume is presented based on the quadtree mesh system,in which a new multiple particle level set(MPLS) method is proposed to solve the problem of interface tracking,in which common intersection may be traversed by multiple interfaces.By using the adaptive mesh technique and the MPLS method,mesh resolution is updated automatically with time according to flow characteristics in the modeling process with higher resolution around the free surface and the solid boundary and lower resolution in less important area.The model has good performance in saving computer memory and CPU time and is validated by computational examples of small amplitude wave,second-order Stokes wave and cnoidal wave.Computational results also indicate that standing wave and wave overtopping are also reasonably simulated by the model.