减P路径下饱和软粘土应力应变性状的试验研究   总被引：12，自引：1，他引：11  

张荣堂  陈守义 《岩土力学》2002,23(5):612-617

对汉口某地的淤泥质粘土进行了一系列应力路径试验。试验表明,饱和软粘土的应力应变性状与应力路径密切相关,在各种减P应力路径下的应力比与轴应变之间均存在着良好的双曲线关系,据此,建立了一个和应力路径有关的归一化应力应变双曲线模型。分析了排水试验中的体变特性和不排水试验下的孔压变化特性。  相似文献   

养殖珍珠的分级与报价体系     

耿宁一  李立平  王刚 《地质科学译丛》2012,(2):47-52

针对我国制定的珍珠分级国家标准,仅对影响珍珠品质各因素做了等级划分,并未给出首饰级珍珠的总品质等级的确定方法和标准,造成分级标准与国际上报价体系不接轨,使其在市场上无法广泛应用等问题,系统总结国际流行的各大珍珠分级标准和报价体系,通过对比分析我国国标存在的问题,提出我国养殖珍珠分级和报价的改进方法。即借鉴美国GIA或RichardH．Cartier的珍珠总品质分级方法,在原国家分级标准上根据各品质因素对总品质影响权重计算珍珠总品质等级（1～10级）;并推行对应珍珠总质量等级的报价体系,呼吁国家权威机构定期发布珍珠价格信息,以规范珍珠市场,为珍珠评估提供依据。  相似文献   

山东唐家沟金矿床地质特征及深部预测     

胡培强 《山东地质》2014,(10):15-20

唐家沟金矿位于胶东牟平乳山金矿带西南段;历经数次勘查工作,近期获得较大突破,累计金金属资源量规模达到近大型。矿区内出露地层主要为古元古代荆山群变质岩及新生界第四系,构造以古元古代褶皱构造和中生代断裂构造为主,其中含金矿化蚀变带受 NNE 向、NE 向、近 EW 向断裂控制。主要控矿构造呈 NNE 向、近 EW向展布,矿石类型主要为黄铁矿化石英脉、黄铁矿化花岗质碎裂岩和黄铁矿化大理岩,矿化具多期活动特点。研究发现,控矿构造局部引张段与其他构造交会处是储矿的有利部位,矿化蚀变叠加地段预示着深部成矿可能性极大。深部预测 NNE 向金矿化断裂构造与 NE 向硫化物富集带交会部位,残留荆山群地层与侵入岩接触部位、接触带与NE 向硫化物富集带交会部位为成矿的有利地带。  相似文献   

Puhimau Thermal Area: A Window into the Upper East Rift Zone of Volcano, Hawaii?     

K. A. McGee  A. J. Sutton  T. Elias  M. P. Doukas  T. M. Gerlach 《Pure and Applied Geophysics》2006,163(4):837-851

We report the results of two soil CO₂ efflux surveys by the closed chamber circulation method at the Puhimau thermal area in the upper East Rift Zone (ERZ) of p6/MediaObjects/s00024-006-0036-zflb2.gif" alt="MediaObjects/s00024-006-0036-zflb2.gif" align="middle"> volcano, Hawaii. The surveys were undertaken in 1996 and 1998 to constrain how much CO₂ might be reaching the ERZ after degassing beneath the summit caldera and whether the Puhimau thermal area might be a significant contributor to the overall CO₂ budget of p6/MediaObjects/s00024-006-0036-zflb2.gif" alt="MediaObjects/s00024-006-0036-zflb2.gif" align="middle">. The area was revisited in 2001 to determine the effects of surface disturbance on efflux values by the collar emplacement technique utilized in the earlier surveys. Utilizing a cutoff value of 50 g mp>−2p> dp>−1p> for the surrounding forest background efflux, the CO₂ emission rates for the anomaly at Puhimau thermal area were 27 t dp>−1p> in 1996 and 17 t dp>−1p> in 1998. Water vapor was removed before analysis in all cases in order to obtain CO₂ values on a dry air basis and mitigate the effect of water vapor dilution on the measurements. It is clear that Puhimau thermal area is not a significant contributor to p6/MediaObjects/s00024-006-0036-zflb3.gif" alt="MediaObjects/s00024-006-0036-zflb3.gif" align="middle"> CO₂ output and that most of p6/MediaObjects/s00024-006-0036-zflb3.gif" alt="MediaObjects/s00024-006-0036-zflb3.gif" align="middle"> CO₂ (8500 t dp>−1p>) is degassed at the summit, leaving only magma with its remaining stored volatiles, such as SO₂, for injection down the ERZ. Because of the low CO₂ emission rate and the presence of a shallow water table in the upper ERZ that effectively scrubs SO₂ and other acid gases, Puhimau thermal area currently does not appear to be generally well suited for observing temporal changes in degassing at p6/MediaObjects/s00024-006-0036-zflb2.gif" alt="MediaObjects/s00024-006-0036-zflb2.gif" align="middle">.  相似文献   

Limits on the source properties of FR-I galaxies from high-energy neutrino and gamma observations     

《Astroparticle Physics》2013

Active galactic nuclei (AGN) are believed to be the source of ultra high energy cosmic rays (UHECRs, pt type="math/mml" id="MathJax-Element-1">pt>). Particles are assumed to be accelerated in the accretion disk and the plasma jets, produced due to conservation of angular momentum, to the highest energies, where they interact with each other and produce pions, which decay among others in neutrinos.For a known cosmic ray (CR) spectral behavior, the main parameters in the calculation of the neutrino flux from proton–proton (p–p) interactions are the target density $n_{\text{H}}$pt type="math/mml" id="MathJax-Element-2">$n_{\text{H}}$pt> and the ratio of electrons to protons $f_{\text{e}}$pt type="math/mml" id="MathJax-Element-3">$f_{\text{e}}$pt>. Using most recent neutrino flux limits from IceCube point source searches, we set limits on the target densities for 33 FR-I galaxies. The densities are shown to be smaller than 30 pt type="math/mml" id="MathJax-Element-4">pt> to pt type="math/mml" id="MathJax-Element-5">pt>, depending on the source and when using a fixed electron to proton ratio of $f_e=0.1$pt type="math/mml" id="MathJax-Element-6">$f_e=0.1$pt>. This implies that some CR acceleration sites, especially those close to the core of the AGN, can already be excluded, or else that the ratio of electrons to protons deviates significantly from the commonly used value of 0.1.For Centaurus A (Cen A) and Messier 87 (M 87) we use Fermi observations to model the $\gamma$pt type="math/mml" id="MathJax-Element-7">$\gamma$pt>-flux, the neutrino flux and the resulting target density. The detection of these neutrinos will help to find information about acceleration processes in the source.  相似文献   

时间序列分析在电离层短期预报中的应用     

张伟  邱卫宁  王刘准  蒋健君 《测绘信息与工程》2014,(4):10-12

根据IGS提供的2012年TEC数据,在得到TEC值残差序列的基础上,利用谱分析去掉周期项和Matlab工具箱去掉趋势项并采用平滑算法去噪后,对随机项进行时间序列分析。目前,电离层格网点的预报均建立在原始TEC上,阐述了采用差分后的TEC值进行预报的方法,以减少日变化周期项的影响。根据AR（p）模型预报的结果加上周期项和趋势项后,再加上前一天对应时段的TEC值与IGS发布的数据比较,结果表明,该方法利用短期IGS发布的TEC值进行电离层预报能取得较高的精度。  相似文献   

基于汶川主震及余震的预警参数与震级相关性研究   总被引：7，自引：0，他引：7       下载免费PDF全文

彭朝勇  杨建思  薛兵  陈阳  朱小毅 《地球物理学报》2013,56(10):3404-3415

地震预警作为一种能够有效减轻地震灾害的手段已经被世界上越来越多的国家和地区所研究,并在实际应用中取得了显著的减灾实效.利用汶川主震及其余震P波和S波初期部分的信息,研究了最终地震震级与4个预警参数的相关性.考察的4个参数是位移幅值(P_d)、速度平方积分(IV2)、P波卓越周期和特征周期(τ_p和τ_c).使用的数据集时间跨度从2008年5月12日至2008年10月4日,共计218次震级大于等于4级的地震事件,包括主震8.0、最大余震6.5和7次大于等于6.0级的事件.P_d、IV2和τ_c在震级小于等于6.5级时与最终震级具有较好的相关性,没有出现震级饱和现象,验证了前人的统计结果.但是在估算主震震级时,都存在不同程度的低估现象,IV2参数尤其明显.另外,P_d和IV2统计曲线在M6级附近存在着一个斜率变化,并且P_d结果与前人统计结果相差较大.τ_p的统计结果表明该参数不适合应用到汶川地区的地震预警系统中.  相似文献   

p‐Nitrophenol Removal by Bauxite Ore Assisted Ozonation and its Catalytic Potential          下载免费PDF全文

Chunmao Chen  Hongshuo Chen  Ji Yu  Chao Han  Guangxu Yan  Shaohui Guo 《洁净——土壤、空气、水》2015,43(7):1010-1017

  相似文献   

Centrifuge modelling of lateral loading behaviour of a “semi-rigid” Mono-pile in soft clay     

Qing-jie Yang  Yu-feng Gao  De-qiong Kong 《Marine Georesources & Geotechnology》2013,31(10):1205-1216

Abstractp>Mono-pile foundations have been widely used for offshore wind turbines principally due to their convenient construction and cost-effective nature. So far, little attention has been paid to large diameter “semi-rigid” piles that have distinct behaviours from flexible or ideally rigid piles. This paper presents a series of centrifuge model tests to study the deforming and bearing characteristics of a 5.9 dia. semi-rigid pile under lateral loadings in kaolin clay. For monotonic loading, a modified p–y curve analysis model considering rotational soil flow near the rotation centre of pile was proposed, highlighting the limitation of classic plane-strain based plasticity models to evaluate the ultimate lateral pile-soil resistance. For cyclic loading, a strong correlation between the degree of soil degradation and cyclic load amplitude was identified. Besides, a degradation factor model, accounting for various cyclic stress levels and soil depths, was proposed, which can be used to assess the accumulative displacement of semi-rigid piles under cyclic loadings in soft clay.  相似文献   

基于平稳自回归模型的地表移动变形预测     

朱小玉  杜仲进  杨虹云 《测绘信息与工程》2012,37(4):29-30

采用AR(p)模型描述随机过程本身观测数据之间的相互关系,根据实测数据建立随机预测模型,对后三期变形量进行预报,并与实测数据进行比较,预报效果良好。  相似文献