首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
胡钧 《上海国土资源》1999,(1):26-30,38
针对新颁国家标准,采用改进的测试技术,对桩基动力特性进行试验研究,取得不同类型基础所相应的测试方法,桩基动力特性参数主要影响因素等方面的结论。  相似文献   

2.
王长虹  朱合华  钱七虎 《岩土力学》2014,35(Z2):386-392
岩土参数的空间分布特征由于存在取样数据之间自相关和互相关的特性,未知点的岩土参数属性可通过特定的方法内插或外推,经典的数理统计方法难以确定周围的数据样本点以及相应的插值系数。首先介绍地统计学中基于距离加权的普通克里金(ordinary kriging, OK)算法、泛克里金算法(UK)和协克里金算法(CK)。由于基于滑动距离加权的OK算法无法度量局部空间的奇异性,将引入多重分形理论弥补该缺陷。以2010上海世博会的世博轴区域(长525 m,宽80 m)为工程背景,区域内共有42个取土钻孔,以典型的粉质黏土层3个重要的物理力学指标,即黏聚力、内摩擦角和压缩模量验证以上算法。对于岩土参数黏聚力和内摩擦角,预测精度由高至低为多重分形联合模型(MK)、协克里金模型(CK)、泛克里金模型(UK)、普通克里金模型(OK);对于岩土参数压缩模量,相应的顺序为泛克里金模型和普通克里金模型位置互换。研究结果证明,在岩土参数空间场的分析中,辅助信息有助于提高数据预测精度,并且多重分形联合模型有助于分析空间局部的奇异性。  相似文献   

3.
Near the outskirts of the Albanian port of Durres on the Adriatic Coast, at a place called Porto Romano, an old chemical complex has been producing chromate salts for a period of ∼20 years (1972–1993). As a result large quantities of chromite ore processing residue (COPR) waste were released mainly as suspended particles and/or dissolved species in effluents, which settled in a decantation pond area, 200 × 250 m in size, east of the industrial plant. Unfortunately, pollutants were spread out with time. Knowing that chromium mobility and toxicity in natural settings is species dependent, the species characterization has been carried out in different sampling media (pond sediments, lagoonal sediments and water samples). Five pond profiles were sampled within the decantation area up to a depth of ∼1 m, till the underlying Quaternary lagoonal silty-clays were reached. Total Cr content is highly variable with values between 1,130 and 24,409 mg/kg which is clearly higher than the defined local background values for lagoonal silty-clays (198 mg/kg of Cr). Leaching of Cr(VI) especially occurs in the pond sediments, which are low in OC, CEC and clay content, under acidic and neutral pH conditions (e.g. up to ∼2,230 mg/kg Cr(VI) leached from a sample containing a total concentration of Cr 12,200 mg/kg). Moreover, leaching of the Cr(III) occurs only under strictly acidic conditions (maximum 1,144 mg/kg leached from a sample containing a total Cr-concentration of 17,608 mg/kg). In this study also a number of natural attenuation conditions (i.e. reaction with lagoonal clays rich in organic matter and iron as well as isomorphous substitution) have been recognized.  相似文献   

4.
Character of the Si and Al Phases in Coal Gangue and Its Ash   总被引:1,自引:0,他引:1  
Abstract: Analysis of the Si and Al phases in coal gangue fuel and its ash is important for use of coal gangue ashes. A comprehensive study by theoretical and experimental analyses with differential thermal analysis, X-ray diffraction and Infrared Spectroscopy has been made in the present article to explore the diagram of the Si and Al phases in coal gangue fuel and its ashes. It is found that kaolinite and quartz are the main phases in coal gangue fuel. The ratio of moles Al2O3 to SiO2 (i.e., Al2O3 (mole) /SiO2 (mole)) is usually no more than 0.5 in most coal gangue fuel and its ashes. The kaolinit at about 984°C releases a large quantity of SiO2, which makes calcine coal gangue more active than coal gangue itself. The relationship between the ratio Al2O3 (mole)/SiO2(mole) and the components of coal gangue ash is analyzed, resulting in a formula to calculate the quantity of each phase. Applying the formula to the testing samples from an electric plant in north China supports the above conclusions.  相似文献   

5.
张翔  丁晶 《水科学进展》2000,11(1):105-110
从神经网络(NN),模糊系统(FS)和进化算法(EC)三者相结合的角度,介绍了神经智能信息处理系统的研究现状,讨论了该系统在水文水资源中的应用,并对其应用发展趋势进行了预测。  相似文献   

6.
在实验室条件下,选择几种有代表性的无机离子(包括宏观生命元素、微量生命元素、副生命元素),并保持一定的浓度和PH值(6.18±0.2),研究了各无机离子和烷化剂对DNATm值的影响。结果表明,有益元素与有害元素对DNATm值高低的影响明显不同。前者使Tm升高,抑制DNA热变性,后者使Tm值降低,促进DNA热变性;这并非阴阳离子的离子强度造成的,而是由于加入的无机离子对DNA分子中磷酸基因和碱基的作用不同所致。而且它们对DNATm值的影响幅度和方向与烷化剂的存在有很大关系。烷化剂可以大大降低Tm值,加入各种无机离子对烷化作用产生不同的影响。这表明,作为致癌的主要机理—烷化作用可能与各种离子的存在和在生物体内的平衡状态有关。所测结果还表明,烷化剂的作用比无机离子大得多。这些结果有助于区分有害与有益元素,对癌症的早期发现及阐明致癌、防癌机理有重要意义。  相似文献   

7.
张先伟  孔令伟 《岩土力学》2013,34(Z2):134-142
近海地区黏土的微观结构单元--黏土畴中含有大量的粒内孔隙,其孔径小至纳米级,这部分孔隙对黏土的物理指标、水稳性、膨胀性、收缩性等具有重要影响,一般方法很难准确地描述其孔隙特征。试验利用扫描电镜、压汞法、氮气吸附法对湛江黏土的微观孔隙特征及其孔隙发育的控制因素分析,建立微观结构与物理指标、力学行为的相互关系与灵敏性分析。结果表明,湛江黏土具有不良物理性质和良好力学特性指标的异常组合,是一种高灵敏性的强胶结结构性黏性土,其机制主要是:湛江黏土的微观结构为带有胶质联结特性的、定向性无序的开放式絮凝结构,孔隙结构为具有较高的强度和空间稳定性的边-面-角联结的空间网架系统。由于特殊的孔隙网架结构以及“墨水瓶”型孔隙的存在,导致退汞过程出现滞留现象及产生吸附回线。研究表明,联合扫描电镜、压汞法、氮气吸附法能够准确、完整地对近海地区黏土孔隙体系特征进行定性与定量的评价。  相似文献   

8.
Speciation of Cr and V within BOF steel slag reused in road constructions   总被引:1,自引:0,他引:1  
Basic Oxygen Furnace (BOF) steel slag is a residue from the basic oxygen converter in steel-making operations, which is partially reused as an aggregate for road constructions. It is essentially composed of calcium, silicon and iron but also contains potential toxic elements present as traces, like chromium (Cr, 2600 mg kg− 1) and vanadium (V, 690 mg kg− 1), which can be released. The linked results of chemical analysis, XRD and SEM-EDX enabled to identify the main mineral phases composing BOF slag and EDX micro-analyses indicated that V and Cr were associated to dicalciumferrite. A 47-days static leaching test at a laboratory scale with a controlled pH of 5 (pHstat leaching test) showed that Cr was little released, while V was significantly released. Finally, X-ray absorption near-edge structure (XANES) spectra of 3 BOF slag samples were recorded (“raw”, leached 47 days at pH 5 and aged 2 years in a lysimeter). XANES spectra showed that Cr is present at octahedral coordination in the trivalent form, the less mobile and less toxic one, and that its speciation does not evolve during natural ageing and leaching at pH 5. They also indicated that V is predominantly present in the + 4 oxidation state and seems to become oxidized to the pentavalent form (the most toxic form) during natural ageing.  相似文献   

9.
INTRODUCTION The properties of phosphor usedin a plasma dis-play panel (PDP) affect the performance of the PDP(Okazaki et al .,2000 ; Rao and Devine ,2000) . Theluminescent properties of the phosphor are decided bythe morphology ,particle size and size distribution ofthe powder ,sothe requirements for the powder mor-phology are high in a color PDP which belongs to ahigh resolution display apparatus (I m et al .,2005 ;Yang et al ., 2005) . Studies have shown that withsmall particle si…  相似文献   

10.
前寒武纪地层中的生物标志物与生命演化   总被引:6,自引:1,他引:5  
史继扬  向明菊 《沉积学报》2000,18(4):634-638
对山西五台、北京十三陵和河北蓟县前寒武纪2.5~0.85Ga岩样中生物标志物地分析研究,发现了正烷烃、类异戊二烯烷烃、烷基环已烷、烷基甲基环已烷、五环三萜烷以及甾烷类等,讨论了生物标志物与前寒武纪生物的演化,提出类异戊二烯是合成早期生物的重要单体,2.5Ga前寒武纪时期,已经产生了厌氧光合细菌和真核生物,原核生物的生成时期可能早于2.5Ga。  相似文献   

11.
东南亚及哀牢山红河构造带构造演化的讨论   总被引:17,自引:1,他引:16  
张进江  钟大赉 《地质论评》1999,45(4):337-344
通过对东南亚和哀牢山红河构造带演化已有模式的分析,在近年来本区海上研究资料的了,结合滇西地质情况,认为东南亚的构造格局是由印度洋、太平洋和欧亚三大构造体系共同作用形成的。60 ̄15MaBP,欧亚构造体系分别与太平洋和印度洋构造体系作用在东南亚东、西部形成两个弧后盆地扩张体系。两体系扩张强度和方向的不同,形成转换调节构造带-哀牢山红河构造带。东部较强的扩张作用使扬子板块向北运动,形成哀牢山以东的逆冲  相似文献   

12.
针对我国油气资源数据相对多源、异构、分散的现状,根据OLAP的实际需求,采用MVC模式作为系统架构模式,实现了国家油气资源数据库数据提取、转换和加载(ETL)系统。阐述了系统所采用的基于面向对象体系结构(SOA)的5层结构模型,使用ODBC和XML技术实现数据库连接的动态映射,应用Oracle DB解决了多媒体数据处理等关键问题。  相似文献   

13.
假玄武玻璃是一种呈暗色的微晶—隐晶质岩石,一般产于古地震断层滑动面,被认为是研究地震活动的"化石岩"。经过碎裂岩化或摩擦熔融,假玄武玻璃发育于从地表到岩石圈地幔的整个地震活动区,其年代学研究对于揭示某一地区古地震活动频次及发生规律有重要意义。假玄武玻璃的定年一般采用Rb-Sr、^40Ar-^39Ar、裂变径迹等三种方法,但Sr的扩散性质、假玄武玻璃内部结构和成分的不均一性及其形成高温快速过程中锆石的退火行为等诸多因素,制约了以上三种方法的应用。文中总结了三种方法,分析了其适用范围和局限性,探讨了假玄武玻璃定年研究中最适用的方法和需注意的事项。最后,阐述了假玄武玻璃研究的地震学指示意义。  相似文献   

14.
钟展环 《岩矿测试》1996,15(2):81-91
研究了高效液相色谱(HPLC)、高效离子色谱(HPIC)、高效离子排斥色谱(HPEIC)和低压离子色谱(LPIC)中有效理论塔板数的变量因素,提出了能定量表述柱分离效率的参数──柱效率S及其计算方法。给出了其它色谱参数(分离度Rs,分离系数α和容量因子K')与有效理论塔板数及柱效率相关的实验结果。  相似文献   

15.
示波计时电位法测定矿石中的镓和铟   总被引:5,自引:0,他引:5  
胡娟  张振海 《岩矿测试》2000,19(2):109-111118
在pH5.0的茜素S-KC1-HAcNaAc-La^3+溶液中,Ga(Ⅲ)、In(Ⅲ)具有良好的示波图,其切口电位为-1.38V和-0.86V(us.SCE)。可分别进行测定。镓的质量浓度在100~1800ug/L内、铟的质量浓度在5~140ug/L内与切口高度呈良好的线性关系,检出限Ga为90ug/L及In为5ug/ L。通过萃取与干扰元素分离之后,对闪锌矿、锡石样品中的镓、铟测定,8次测定的RS  相似文献   

16.
The present study is based on the observed features of the MBL (Marine Boundary Layer) during the Bay of Bengal and Monsoon Experiment (BOBMEX) — Pilot phase. Conserved Variable Analysis (CVA) of the conserved variables such as potential temperature, virtual potential temperature, equivalent potential temperature, saturation equivalent potential temperature and specific humidity were carried out at every point of upper air observation obtained on board ORV Sagar Kanya. The values are estimated up to a maximum of 4 km to cover the boundary layer. The Marine Boundary Layer Height is estimated from the conserved thermodynamic profiles. During the disturbed period when the convective activity is observed, the deeper boundary layers show double mixing line structures. An attempt is also made to study the oceanic heat budget using empirical models. The estimated short-wave radiation flux compared well with the observations.  相似文献   

17.
廖先斌  郭晓勇  杜宇 《岩土力学》2013,34(1):143-147
为了在国内岩土设计中很好利用英国标准(BS)标贯设备的试验结果,对英国标准和中国标准(GB)标贯设备及试验结果进行分析,研究相关性。BS和GB标贯设备主要的区别是前者的锤垫质量大于后者,造成试验时两者锤击能量有差别,因此,获得的标贯击数不同。通过采用标贯能量分析仪,测量配置不同直径钻杆的BS和GB设备试验时的实际锤击能量,计算两者不同的实际锤击能量与理论锤击能量的能量比,利用能量比的差别分析BS与GB标贯击数的相关性,建立相关公式。分析显示,试验时BS标贯设备比GB标贯设备的锤击传递能量要小,标贯击数要大;钻杆直径为50 mm比直径为42 mm传递的锤击能量略高,标贯击数略低。通过研究,最终建立了BS与GB标贯设备试验结果的相关关系,英标标贯设备获得的数据从而能更好运用于中国标准中,并提供符合中国利用标贯评价的岩土设计参数。  相似文献   

18.
提要:油气成藏年代学是多旋回叠合盆地油气成藏动力学研究的热点问题。运用钻井岩心样品的自生伊利石同位素定年和流体包裹体间接定年方法,探讨分析了鄂尔多斯盆地东北部二叠系多期次油气成藏的时间和期次。含油气砂岩自生伊利石年龄以较宽的时间域分布在178~108 Ma,测年数据的统计分布特征指示二叠系原生油气成藏时间主要集中在175~155 Ma和145~115 Ma两组主值年龄区间,相应的峰值年龄为165 Ma和130 Ma。流体包裹体测温数据的统计分析与其宿主砂岩磷灰石裂变径迹热史模拟路径的投影关系表明,二叠系不同层段共同经历了与90~78 ℃和125~118 ℃两组统计峰温相应的162~153 Ma和140~128 Ma两期原生油气成藏事件,其中的上二叠统则还经历了统计峰温接近98 ℃、峰值年龄接近30 Ma的一期次生油气成藏事件。由此认为,鄂尔多斯盆地东北部二叠系不同层段在中生代早—中期的多旋回沉降增温过程至少经历了165~153 Ma和140~128 Ma的两期原生油气成藏作用,上二叠统则在晚白垩世以来盆地后期抬升改造阶段的构造动热转换过程经历了接近30 Ma的一期次生油气成藏作用。  相似文献   

19.
利用MODIS NDVI数据、同期地表水热组合数据和植被类型数据,对2000-2014年蒙古高原生长季和三季(春、夏、秋季)植被覆盖时空演变特征及其对地表水热因子响应模式进行分析。研究表明:这15 a来,蒙古高原生长季及三季归一化植被指数NDVI均呈增加趋势,且呈显著增加趋势区域主要集中在内蒙古地区,一定程度上反映了该地区生态恢复工程的有效性。研究区植被覆盖变化与地表水分指数LSWI有密切的关系,因此证明研究区植被覆盖的增加归因于自然和人为因素的共同作用。不同类型植被NDVI均呈增加趋势,其中荒漠植被NDVI增加最明显,森林植被增加平缓,且存在季节性差异。此外,不同类型植被NDVI受水热因子影响也存在季节性差异。  相似文献   

20.
Manganese (oxy)hydroxides (MnOX) play important roles in the oxidation and mobilization of toxic As(III) in natural environments. Abiotic oxidation of Mn(II) to MnOX in the presence of Fe minerals has been proved to be an important pathway in the formation of Mn(III, IV) (oxy)hydroxides. However, interactions between Mn(II) and As(III) in the presence of Fe minerals are still poorly understood. In this study, abiotic oxidation of Mn(II) on lepidocrocite, and its effect on the oxidation and mobilization of As(III) were investigated. The results show that MnOX species are detected on lepidocrocite and their contents increase with increasing pH values ranging from 7.5 to 8.4. After 10 days, an MnOx component, groutite (α-MnOOH) was found on lepidocrocite. During the simultaneous oxidation of Mn(II) and As(III), and the As(III) pre-adsorbed processes, the presence and oxidation of Mn(II) significantly promotes the removal of soluble As(III). In addition, MnOx formed on lepidocrocite also contributes to the oxidation of soluble and adsorbed As(III) to As(V), the latter being subsequently released into solution. In the process where Mn(II) is pre-adsorbed on lepidocrocite, less As(III) is removed, given that the active sites occupied by MnOx inhibit the adsorption of As(III). In all experiments, the removal percentages of As(III) and the release of As(V) are correlated positively with pH values and initial concentrations of Mn(II), although they are not apparent in the Mn(II) pre-adsorbed system.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号