Analysis on Bearing Capacity of Tunnel-Type Anchorage of a Long-Span Suspension Bridge

INTRODUCTION Tunnel typeanchoragehasobviousadvantages inbearingcapacityversusinvestment(LiuandHu,1996).However,itisrarelyusedinapracticalpro jectbecauseofitsrequirementofgoodrockcondi tions.Siduhebridge(Fig.1),whichliesintheBa dongmountainsinthewestplatea…     

The effects of land use on runoff and soil nutrient losses in a gully catchment of the hilly areas： implications for erosion control

1 Introduction Soiland waterlossisoneofthe worldwide environm entalissuesthreatening sustainable land use in semiarid areas.However,soiland water loss is highly variable in space and time,and its variability resultsfrom m any factorsoperating ata wide ran…     

Statistical Properties of Alfvén Ion Cyclotron Waves and Kinetic Alfvén Waves in the Inner Heliosphere

Alfvén ion cyclotron waves(ACWs) and kinetic Alfvén waves(KAWs) are found to exist at <0.3 au observed by Parker Solar Probe in Alfvénic slow solar winds. To examine the statistical properties of the background parameters for ACWs and KAWs and related wave disturbances, both wave events observed by Parker Solar Probe are selected and analyzed. The results show that there are obvious differences in the background and disturbance parameters between ACWs and KAWs. ACW events have a relatively hi...     

Organic carbon and nitrogen stable isotopes in the intertidal sediments from the Yangtze Estuary, China

The natural isotopic compositions and C/N elemental ratios of sedimentary organic matter were determined in the intertidal flat of the Yangtze Estuary. The results showed that the ratios of carbon and nitrogen stable isotopes were respectively −29.8‰ to − 26.0‰ and 1.6‰–5.5‰ in the flood season (July), while they were −27.3‰ to − 25.6‰ and 1.7‰–7.8‰ in the dry season (February), respectively. The δ¹³C signatures were remarkably higher in July than in February, and gradually increased from the freshwater areas to the brackish areas. In contrast, there were relatively complex seasonal and spatial changes in stable nitrogen isotopes. It was also reflected that δ¹⁵N and C/N compositions had been obviously modified by organic matter diagenesis and biological processing, and could not be used to trace the sources of organic matter at the study area. In addition, it was considered that the mixing inputs of terrigenous and marine materials generally dominated sedimentary organic matter in the intertidal flat. The contribution of terrigenous inputs to sedimentary organic matter was roughly estimated according to the mixing balance model of stable carbon isotopes.     

Results of 23 yr of Pulsar Timing of PSR J1453-6413

In this paper, we presented the 23.3 yr of pulsar timing results of PSR J1456-6413 based on the observations of Parkes 64 m radio telescope. We detected two new glitches at MJD 57093(3) and 59060(12) and confirmed its first glitch at MJD 54554(10). The relative sizes(Δν/ν) of these two new glitches are 0.9 × 10^-9and 1.16 × 10^-9,respectively. Using the “Cholesky” timing analysis method, we have determined its position, proper motion, and two-dimensional transverse velocities...     

美国地球物理学会1980年春季年会

美国地球物理学会1980年春季年会于5月22日至27日在加拿大多伦多市举行。这是该学会自1919年创建以来首次在国外并与加拿大的同行学会共同组织的一次年会。与会者近3,000人,盛况空前。我国有4名在美进修工作的科学工作者也参加了会议。 年会共收到论文1,613篇,内容极其广泛。包括高空物理,行星、太阳及星际物理,宇宙线,海洋,水文,气象,火山、岩石及地球化学,构造物理,地磁及古地磁,地震学,大地测量,勘探地球物理等14个学科。除少数共同感兴趣或具有特殊价值的论文在大会宣读外,其他均在各学科分组会上宣读。     

东海天然气水合物地热研究及其环境意义

依据地热资料研究天然气水合物稳定带厚度在东海海域的分布情况。东海在地质构造上位于新生代环太平洋构造带西部边缘岛弧的内侧,又是欧亚板块、太平洋板块和菲律宾海板块的相互作用带。依据国际热流委员会(IHFC)提供的东海地热数据,经过统计确定出该区域的热流分布,热流平均值为121·0mW/m2,最小值为73·0mW/m2,最大值为168·0mW/m2。同时利用天然气水合物温压模型计算了稳定带厚度,数据显示稳定带厚度平均值为92·2m,最小值为1·4m,最大值为190·6m,薄于其他已经发现的海洋天然气水合物稳定带厚度(约400m)。天然气水合物大部分分布在条件适宜的陆坡和岛坡上,冲绳海槽底部水合物稳定带厚度相对较薄。统计分析表明本区热流值与水合物稳定带厚度相关性很差,相关系数仅有0·12。这是由于天然气水合物所在海域水深较浅时,海底温度的变化迫使运算所应用的非线性方程影响因子迅速积累,从而导致相关系数降低。最后结合东海陆坡的地质条件,探讨了在天然气水合物存在的情况下,陆坡失稳的可能性及其造成的环境影响。