Some Problems in the Design of Breakwaters in Dayaowan Port Area

- In this paper, some problems in the design of the breakwater for Dayaowan port area are described including the optimal selection of the layout plan of the breakwater; the selection of structural type of the breakwater, the concrete block type for bank protection, the reversed L-shape parapet; the elevation of the parapet; the stability test of the whole revetment; as well as wave absorbing effects of the perforated     

Dynamic Analysis of a Single-Column Platform

In this paper, a single-column structure used as well-head platform is studied. The loads of wave and current exerted on the single-column will be greatly reduced, therefore the cost of the structure will be decreased. The advantages of the single-column structure compared with ordinary jacket structure are explained. A dynamic analysis of this type of structure is made and some problems related to dynamic analysis are solved. In order to check the reliability of computation theory and programme, model tests have been carried out. However, as space is limited, the conclusion of tests will be introduced in another paper. Therefore, this type of structure is applicable for proctical engineering.     

Computation of Diffraction of Irregular Waves Behind Double Jetty

The coefficient of deffraction of regular waves behind the double jetty has been computed in this paper at first by using the singularity distribution method. The model tests conducted for diffraction of irregular waves with a unidirectional frequency spectrum have confirmed good agreement between the data measured in experiments and the results computed by the singularity distribution method plus the linear superposition method for the energy of component waves in the directional frequency spectra. Therefore, this technique for component waves in the directional spectra has been further used to compute diffraction of irregular waves of multidirection, including the employment of a directional distribution function of the cos2 type, as well as the Bretschneider-Misuyann frequency spectrum.     

Design of Submarine Pipeline in BZ34-2/4 Oil Field

This paper presents the detail design conditions, design criteria and methods as well as design conclusions of the process, structure and corrosion of the production flowlines and high pressure water injection lines in BZ34-2 / 4 oil field in Bohai Bay. At present this design represents the design capability and level in the field of the submarine pipeline engineering of China.     

针对简化路网的基于序列的双向合并地图匹配算法

简化路网具有结构简单、算法运行速度快的特点,对地图匹配算法的基础研究具有应用价值。本文针对简化路网的GPS轨迹数据地图匹配问题提出了一种基于序列的双向合并算法。实验结果表明:本算法不仅具有较好的匹配度,还优于现有的Passby算法和增量算法,并且在匹配过程中解决了遗漏路段和极值等错误问题。所以,本算法对于实际路网的地图匹配具有较好的借鉴作用。     

Reduced ARAIM monitoring subset method based on satellites in different orbital planes

With the development of the Global Navigation Satellite System, the increased number of satellites has resulted in more fault hypothesis situations and subset solutions. This situation represents a new challenge for advanced receiver autonomous integrity monitoring (ARAIM) in terms of the computational load. To efficiently detect faults and reduce the computational load, a method based on the association between satellite features in the same orbital plane is proposed. This approach first tests subsets that exclude entire constellations to narrow the search range for faults. Next, we evaluate multiple-fault cases directly by utilizing the subsets that exclude entire orbit satellites. Compared with the baseline Multiple Hypothesis Solution Separation (MHSS) method, our method can clearly reduce the number of subsets and the computational time under a typical multi-constellation situation while satisfying the localizer precision vertical 200 performance requirement, i.e., the guidance supports approach operations down to 200-foot altitudes. Furthermore, the experimental results illustrate that the number of subsets is reduced at most by two orders of magnitude, from 1330 to 87, and the computational time is decreased by 66.6%. The effective monitoring threshold and the fault-free 10^?7 error bound on the accuracy of our method are much closer to those of the baseline MHSS method, and the usability coverage of both methods reaches 100%. This study verifies that the monitoring subsets and the calculation time for ARAIM are dramatically reduced by the new method.     

基于GIS的斜坡单元划分方法改进与实现

斜坡单元已广泛应用于滑坡易发性制图和地质灾害评价。然而在山间盆地或大型宽谷处,常规方法划分出的斜坡单元与地貌背景难以匹配。依据高程及其衍生变量的基本形态系统和曲率的流域分割原理,基于ArcGIS技术,通过叠加曲率和反转曲率的流域边界,改进了斜坡单元划分方法。结果表明：与常规方法相比,改进方法不仅能够使用山脊线和山谷线以划分斜坡单元,还能利用台地边界和宽谷边界以分割水平地表与倾斜地表;划分出的单元大小相对均匀,单元形状总体介于圆形和正三角形之间。对于水平成分较多的地区,如黄土塬区和水库库区,该方法与传统方法相比,具有较好的应用前景。     

2013年8月沙澧河流域一次连续暴雨过程成因分析

利用常规观测资料和NCEP 1°×1°再分析资料,对2013年8月24—25日河南省沙澧河流域的连续暴雨过程进行分析。结果表明：本次连续性暴雨过程共分为两部分,前一部分是台风“谭美”外围的螺旋云带导致,后一部分转为低槽切变线影响,转折点在24日20时之后。偏东急流为暴雨提供了充沛且持久的水汽条件,水汽通量高值区集中在800 hPa以下的低层和边界层。垂直螺旋度计算结果显示,850 hPa等压面上正垂直螺旋度中心的移向和强度变化与降水落区及趋势变化有很好的对应关系,大暴雨中心位于正垂直螺旋度中心附近,正垂直螺旋度中心位置对大暴雨落区有一定的指示意义;中低层正、高层负的垂直螺旋度配置,动力条件非常有利于强降水产生。湿位涡演变分析发现,此次过程中低层既存在对流不稳定,又存在对称不稳定,有利于垂直对流和倾斜对流发生,导致上升运动和水汽输送加强,有利于降水增幅。雷达回波演变特征表明,回波的后向传播、列车效应及准静止等特征,导致降水量增加,暴雨发展。     

DEFORMATION AND ROUGHNESS CHANGES OF THE MAIN CHANNEL AND FLOODPLAIN IN FLOOD EVENTS (CASE STUDY )

LINTRODUCTIONAsfear7specificsurveyshavebeenmadeonthemorphologicalbehavioroftheHuaihefox'erinthepast.Someinformationofbeddeformationduringfloodprocesshavebeenobtained.Beingrelativelystable,theHuaihehiverusedtobeineptlytreatedas"fixedbed".Fortunately,tilehydrometricalstationsweredenselydistributedalongtheHuaihehiverinthe1950s,andthevelocitylareamethodwasusedforthedeterminationofdischarge.Themeasurementsofdischargearelistedin"TheDischargeMeasurementsTable"intheHydrologicalYearbooks.Sinc…     

Variation of γ-Ray and Particle Fluxes At the Sea Level During the Total Solar Eclipse of 24 October, 1995

A Total Solar Eclipse (TSE) was observed from Diamond Harbour (lat. 22.2°N, long 88.2°E) on 24 October 1995. The variation of -ray intensity was measured in the energy range of 0.3–3.0 MeV for different time spans throughout the period of the eclipse. A CR-39 detector was used to look at the change in the fluxes of neutral and charged particles. The maximum drop ( 25%) in the intensity of -ray was observed in the range 2.5–3 MeV during TSE. The CR-39 results showed the appearance of a good number of tracks and a small variation of proton and neutron flux of 10% which was not significant statistically. Low energy -ray fluxes at sea level originate from the secondary electron-photon components of cosmic rays in the atmosphere; its modulation by TSE is interpreted as follows. The cooling of the atmosphere in the path of the umbra induces a reduction of the height of the main production layer of the nuclear component, as a result of which, fewer µ^± mesons (from the decay of the^± mesons) decay to e^±. This leads to a small reduction in the flux of electron-photon component at sea level which originates from this branch; the main branch of e - component from ⁰ decay remains nearly unaffected. As the total mass of air remains the same, little or no change in the slow proton or the neutron flux at sea level is expected. These are consistent with the present observations. For a better understanding, further studies of this new phenomenon during future TSE are suggested.