浙江南部近海沉积物柱状样中脂类生物标志物的组成及形态分布

分析了浙江南部近海(东海陆架泥质区)沉积物柱状样中游离态和碱不稳定结合态脂类生物标志物的组成.沉积物中的脂肪酸呈现以C16脂肪酸为主峰的单峰形分布趋势,具明显偶碳优势,除表层沉积物中脂肪酸以游离态为主外,结合态为柱状样中脂肪酸的主要存在形态,脂肪酸的垂直分布主要由降解作用控制;以甾醇和脂肪醇为主体的醇酮组分主要以游离态...     

沟谷型沙漠泥流堆积体起动过程中的孔压变化特性

以黄河上游宁蒙段典型风水复合侵蚀流域为研究区域,重点针对堆积体堵塞沟道极端条件下的沟谷型沙漠泥流,从堆积体起动成灾的环节入手,开展直槽概化模型试验,并采用基于有效应力原理的流固耦合模型,概化模拟上游暴雨洪水入渗条件下堆积体内孔隙水压力变化特性及其起动过程,从微观角度揭示其成灾机理。结果表明：堆积体起动过程中孔隙水压力与时间呈指数为0.5的幂函数关系;流固耦合作用下堆积体内经历了应力场→体积应变→孔隙率→孔隙水压力→渗流场→塑性应变→屈服破坏的复杂非线性变化过程。     

Non-equilibrium flocculation characteristics of fine-grained sediments in grid-generated turbulent flow

Results are presented from a series of settling column experiments investigating temporal variations in the flocculation characteristics of purely cohesive (kaolin clay) sediment suspensions and cohesive (kaolin) and non-cohesive (fine sand) sediment fraction mixtures. Experimental runs were conducted under controlled hydrodynamic conditions generated by a rigid array of in-phase oscillating grids. The results indicated that rapid initial floc aggregation occurred under low turbulent shear rates, with peak maximal and root-mean-square (r.m.s.) floc sizes (∼ 400 μm and ∼ 200 μm, respectively) attained after relatively short time periods, before reducing with time. By contrast, lower aggregation rates and smaller floc sizes were observed under higher shear conditions, with flocs retaining suspended in the settling column for longer time scales due to the increased turbulence. The mud input concentration displayed some correlation with maximal and r.m.s. floc sizes at higher shear rates but no correlation was apparent at low shear rates. This observed floc behaviour may be attributed to the differences in concentration gradients at high and low shear rates that affect both floc settling rate and time required for flocs to attain equilibrium size. The addition of the fine sand fraction to the kaolin clay suspension reduced both the initial floc formation (i.e. aggregation) rate and the maximal and r.m.s. floc sizes attained throughout the experiments. The reduction in maximal floc sizes appeared to be enhanced by an increase in the ratio of fine sand to kaolin clay content within the mixture.     

王588块泥浆污染深穿透酸液研究与评价

王588块钻井泥浆污染主要是固相入侵和滤液与地层水的不配伍性。通过实验,优选出了具有高效深穿透能力以及固相溶解量大的表面活性剂DS-101酸液复配体系。实验表明,该体系耐温性强,对油泥具有极强的分散和溶解作用,对泥浆污染有明显的解堵效果,岩心渗透率恢复率可达127%。     

火山活动状态及其机理的初步探讨

根据火山喷发实例总结了火山喷发在不同阶段的活动状态,并探讨了可能的物理机理。火山活动从岩浆补给到岩浆喷发的物理过程可分为3个阶段:1)岩浆补给阶段,岩浆囊压力差或过剩压力的大小决定了火山活动是否休眠或扰动,岩浆补给速率对压力差起了决定性的作用;2)通道形成阶段,当过剩压力超过围岩破裂强度时,围岩开始破裂,之后水热活动起了重要的作用;3)岩浆运移与失稳喷发阶段,主要是岩浆运移与地壳盖层的相互作用与失稳的过程。文中还讨论了火山活动状态与火山喷发危险性等级之间的关系,7个危险性等级分别对应于火山活动的7种状态,即休眠、平静、扰动、动荡、临界、活动、灾变     

Estimation of tsunami hazard from volcanic activity — Suggested methodology with Augustine volcano,Alaska as an example

A general approach for the estimation of tsunami height and hazard in the vicinity of active volcanoes has been developed. An empirical relationship has been developed to estimate the height of the tsunami generated for an eruption of a given size. This relationship can be used to estimate the tsunami hazard based on the frequency of eruptive activity of a particular volcano. This technique is then applied to the estimation of tsunami hazard from the eruption of the Augustine volcano in Alaska. Modification of this approach to account for a less than satisfactory data base and differing volcanic characteristics is also discussed with the case of the Augustine volcano as an example. This approach can be used elsewhere with only slight modifications and, for the first time, provides a technique to estimate tsunami hazard from volcanic activity, similar to a well-established approach for the estimation of tsunami hazard from earthquake activity.     

离心式泥浆机械净化设备的研制与应用

本文介绍了两种离心式泥浆净化设备——NL-227型离心除泥器和WL-230型连续除泥离心机的结构、特点和应用效果,讨论了几种净化设备的分离物的粒度分布.     

江苏北部开敞淤泥质海岸的侵蚀过程及防护

开敞淤泥质海岸是淤泥质海岸的主要类型，其自然演变过程，主要受沿海河流泥沙供应条件的制约，一旦泥沙供应消失，海岸往往进入不可逆转的侵蚀过程。江苏北部淤泥质海岸的侵蚀过程，起自１８５５年黄河入海口北归利津入海以后，主要是在近岸破波对岸滩物质的冲刷和潮流的输移扩散作用下进行的。通过对淤泥质海岸动力和沉积物性质的认识和概化，对海岸侵蚀过程作出定量模拟，并对该地区海岸防护工程作出评价和讨论。