定向钻进铺管施工用高密度聚乙烯管的设计准则

高密度聚乙烯管用作自来水,煤气和排污管道,进行河流穿越和城市基础设施更换,基应用正迅速增长,水平定向钻进和导向钻进是铺设可张拉,无泄漏的热熔焊接式ＨＤＰＥ管的理想技术。然而,ＨＤＰＥ管的选择不仅取决于管柱运行过程中的应力情况,还同等程度地取决于施工过程中管柱的应力情况。本研究对用于非开挖施工的聚乙烯管的主要设计准则进行概要的探讨。     

从格陵兰获取的完整冰期旋回的第一支甲磺酸盐和硫酸盐的冰芯记录

冰芯中的甲磺酸盐作为过去海洋逸出的二甲基硫化物的可能示踪剂已引起了注意。除了硫酸盐以外，ＭＳＡ是ＤＭＳ的第二个重要的气溶胶氧化产物，但与硫酸盐对比，ＤＭＳ氧化是ＭＳＡ已知的唯一来源。Ｃｈａｒｌｓｏｎ等提出的海洋浮游植物逸出的硫影响云反照的气候反馈机理的假说，增加了建立跨越大的气候变化的ＭＳＡ和非海盐硫酸盐长期记录的兴趣。     

Identification and Expression of the Conotoxin Homologous Genes in the Giant Triton Snail(Charonia tritonis)

Conotoxin(CTX) is a small peptide toxin, and plays crucial role in anesthetizes prey, preys and defends competitors.Charonia tritonis is the natural predator of the crown of thorns starfish(CoTS) and the protector of coral reefs. It plays an important role in the coral reef ecosystem. However, the types of toxins produced by tritons and the molecular mechanisms of toxin secretion of C. tritonis are unknown. In the present study, the four conotoxin homologous genes(CTXs) from C. tritonis were ide...     

Distribution and Controlling Factors of Dissolved Gaseous Mercury and Reactive Mercury in Seawater Near Yangtze River Estuary

Complex hydrocultural conditions in the estuary affect the migration and transformation of mercury. Using two voyages in July and October 2018, Dissolved Gaseous Mercury(DGM) and Reactive Mercury(RHg) were determined to explore the source, transformation and influence of DGM content in the adjacent waters of Yangtze River Estuary in summer and autumn. The results showed the contents of DGM and RHg in summer were higher than those in autumn, and both of them were higher than those in open sea. In...     

Deformation and failure mechanism of Yanjiao rock slope influenced by rainfall and water level fluctuation of the Xiluodu hydropower station reservoir

With the construction of the Xiluodu hydropower station on the Jinsha River, the reservoir impoundment began in 2013 and the water level fluctuates annually between 540 m and 600 m above sea level. The Yanjiao rock slope which is located on the left bank of the Jinsha River 75 km upstream of the Xiluodu dam site, began to deform in 2014. The potential failure of the slope not only threatens Yanjiao town but also affects the safe operation of the Xiluodu reservoir. This paper is to find the facto...     

3D Motion parameters determination based on binocular sequence images

Introduction Amongexistingvisionmoniteringandtheesti mationof3Dmotion,nearlyallinvestigations aremoniteringandtracingthemotionobject basedonsinglesequenceimages.Themotionin formationbyanalyzingthesinglesequenceima gesisrelative,whichincludesascaleoffactor…     

On Newton-like methods for solving nonlinear equations

Introduction Manymethodsforsolvingnonlinearequations aredescribedindetail[1,2].TheNewtonmethod fortheapproximationofarootofnonlinear equationf(x)=0isanimportantandbasic method,whichconvergesquadratically.The Newtonmethodanditsdeformationsarefocused onallt…     

A STUDY ON SEDIMENT PROBLEMS IN THE GONGZUI RESERVOIR

IINTRODUCTIONTheannualaverageruff-offinthewatershedoftheGongzuiReservoiris50billioncubicmeterswithanaveragesedimentloadof34.7milliontonsperyear.Finesedimentwithd,,=0'055mmcompose97%oftheiota]sedimentload.Theannualcoarsegravelpericleswithd,,=58.5mmisaboutonemilliontons.TheendofbackWateris38kmawayfromthedam.Thereservoirwasoriginallydesignedtoatotalstoragecapacityof374millioncubicmeters,inwhich102millioncubicmetersisregulationstoragecapacityand243millioncubicmetersis'dead'storagecapacityfo…     

Effect of aluminium dust on secondary organic aerosol formation in m-xylene/NO_x photo-oxidation

As an important anthropogenic volatile organic compound(VOC), m-xylene has attracted numerous attentions due to its potential in secondary organic aerosol(SOA) formation. In this study, effects of aluminium dust seeds(boehmite and alumina) on SOA yield and aerosol size in m-xylene/NOx photo-oxidation were investigated in a 2 m3 smog chamber at 30°C and 50% relative humidity. Compared to the seed-free system, the presence of aluminium seeds resulted in an increase in the SOA yield, and also enhanced the O3 concentration in the chamber. The photolysis of O3 is a major source of OH radical, which is the most important oxidant of m-xylene. The increase in O3 concentration could result in the generation of more OH radicals, and finally contribute to the SOA formation. Seed particles influence the SOA size mainly by acting as condensation nuclei. Semi-volatile organic compounds(SVOCs) were condensed onto these nuclei, resulting in the increase in SOA size. However, when aluminium seeds with high concentrations were introduced into the system, SVOCs that had been condensed onto each particle were dispersed by these seeds, leading to the reduction in aerosol size.