Hydrodynamic characteristics and sediment transport of a tidal river under influence of wading engineering groups

By taking the Yong River for example in this paper, based on the multiple measured data during 1957 to 2009, the change process of runoff, tide feature, tidal wave, tidal influx and sediment transport are analyzed. Then a mathematical model is used to reveal the influence mechanism on hydrodynamic characteristics and sediment transport of the wading engineering groups such as a tide gate, a breakwater, reservoirs, bridges and wharves, which were built in different periods. The results showed the hydrodynamic characteristics and sediment transport of the Yong River changed obviously due to the wading engineering groups. The tide gate induced deformation of the tidal wave, obvious reduction of the tidal influx and weakness of the tidal dynamic, decrease of the sediment yield of flood and ebb tide and channel deposition. The breakwater blocked estuarine entrances, resulting in the change of the tidal current and the reduction of the tidal influx in the estuarine area. The large-scale reservoirs gradually made the decrease of the Yong River runoff. The bridge and wharf groups took up cross-section areas, the cumulative affection of which caused the increase of tidal level in the tidal river.     

The Regularity of Relative Movement Among Crevices in Lianziya

This paper summarizes and interprets the data observed from relative movement among crevices in Lianziya in the past seventeen years. The regularity of relative movement among crevices is obtained and the development tendency of dangerous rock masses is analyzed, which can be used to estimate the stability of Lianziya.     

焦耳效应标定高温卡尔维微量热计

根据热流式量热计的Tian氏方程,用焦耳效应标定高温卡尔维微量热计。用偏差法得到的灵敏度值与积分法测得的值一致。用回归曲线对灵敏度实验值进行拟合,利用计算机求得灵敏度—温度回归曲线,得到了室温至700℃的全部灵敏度值,从而即可使用微量热计测量此温度范围内的未知样品热效应。     

ON SOME KEY SEDIMENTATION PROBLEMS OF THREE GORGES PROJECT (TGP)

I. INTRODUCTIONThe Three Gorges Project (TGP) being planned is to be located on the Yangtze River at Sandouplug, 44 km upstream of Yichang (Fig. l). A scheme studied in the feasibility stage has the crest ofthe dam placed at 185 m with a maximums height o…     

用β—γ1.46Mev测定含钾样中的铀

在β-γ综合测铀基础上,用大晶体、大道宽,突出~(40)K的11.46MeVγ贡献,使钾的铀当量趋近零值,可以实现含钾样中铀的准确测定。     

北京市区冬季大气气溶胶空气动力学尺度谱分布的研究

本文讨论了北京市区冬季大气气溶胶空气动力学尺度的各种谱分布,发现平均粒子谱为单峰型,而平均表面积谱和平均质量谱则通常为三峰型。但是,表面积谱和质量谱随时间变化明显。 三峰型质量谱与国外给出的城市双峰型质量谱差别显著,揭示了我国目前城市气溶胶污染所具有的一种带普遍性的重要特性。     

我国多雨季和少雨季的一些统计特征

通过对我国31年124季降水距平图的分析发现1.全国性的特多(少)雨季中,在高原东侧(95—105°E间)总有一少(多)雨带出现。2.多(少)雨季之后仍为多(少)雨季的持续性以春一夏最好,秋冬最差。3.一年中出现多雨季的次数与黑潮海温和西太平洋副高强度呈正相关。     

A FUMIGATION DIFFUSION MODEL DURING THE MOUNTAIN-VALLEY WIND SHIFT PERIOD

The fumigation during the mountain-valley wind shift has been first identified as a special type of pol-lutant diffusion using the monitoring measurements of Dukou,Southwest Sichuan,China.Such a pheno-menon occurs frequently all year around but summer,particularly in winter months.A new model for thefumigation during the mountain-valley wind shift period is developed that allows satisfactory explanation ofthe fact.Analyses indicate that the model can more accurately predict not only the high concentration ofPollutants but the time and locality of the occurrence as well.The ground concentration of SO_2 during fumigation is several times up to over a decade higher thanthe daily mean for the whole region,one of the main contamination processes that affect the air quality ofthe city.The medel analyses provide a basis for more effective prediction of the quality and precautionstudy against the disaster.     

Late quaternary monsoon patterns on the Loess Plateau of China

China's Loess Plateau was formed under special conditions. The tectonic movement, topographical characteristics, and monsoon patterns combined to create a favourable environment for the accumulation of thick loessic deposits. The Loess Plateau itself is part of the ‘Monsoon Triangle’ of China, a region very susceptible to climatic changes. Throughout the Upper Pleistocene the palaeoenvironment on the Loess Plateau alternated from steppe, to deciduous forest and coniferous forest, in response to shifts in the atmospheric circulation. Three monsoon patterns appear to be indicated: (1) a full glacial monsoon pattern (18000–15000 yr BP) which induced a cold and dry climate favouring loess accumulation in steppe conditions; (2) an interglacial monsoon pattern (last interglacial and Holocene) in which a warm humid climate prevailed with deciduous forests, leaving palaeosols interbedded within the loess sequence; and (3) a transitional or interstadial monsoon pattern (50 000–23 000 yr BP) in which the climate was cold and humid in the Loess Plateau, encouraging the development of coniferous forest.     

岩石压剪性断裂特性及Ⅰ—Ⅱ型复合断裂判据

本文系统阐述了岩石压剪性断裂的特性,认为金属断裂力学复合断裂判据基本上不适用于压剪状态下的岩石斯裂;在此基础上,提出了新的岩石压剪性断裂判据:2COSθ_0/2(cosθ_0-1)[(1+1/f~2)~(1/2)-1]K_Ⅰ+[(sin θ_0/2-3sin 3θ_0/2)(1+1/f~2)~1/2+4sin θ_0/2]K_Ⅱ=4K_(Ⅰc),推导了起始断裂角ψ_0,说明了实验验证结果,指出了该判据在工程地质领域中的应用途径。