基于“钻石模型”的我国地理信息产业国际竞争力分析

利用波特"钻石模型"理论,从生产要素、需求条件、结构与竞争、相关支持产业、政府推动和机会等六个方面对我国地理信息产业竞争力进行了分析,找到了我国地理信息产业在国际发展道路上存在的优势和不足,并提出相应对策。     

浅谈包头市1∶5000地形图缩编技术

主要介绍利用大比例尺地形图数据进行缩编的技术方法,以及在编制过程中的综合取舍原则.     

An elastoplastic constitutive model for frozen saline coarse sandy soil undergoing particle breakage

The mechanical property of frozen saline sandy soil is complicated due to its complex components and sensitivity to salt content and confining pressure. Thus, a series of triaxial compression tests were carried out on sandy samples with different Na₂SO₄ contents under different confining pressures to explore the effects of particle breakage, pressure melting, shear dilation and strain softening or hardening. The test results indicate that the stress–strain curves exhibit strain softening/hardening phenomena when the confining pressures are below or above 6 MPa, respectively. A shear dilation phenomenon was observed in the loading process. With increasing confining pressure, the strength firstly increases and then decreases. By taking into consideration the changes between the grain size distributions before and after triaxial compression tests, a failure strength line incorporating the influences of both particle breakage and pressure melting is proposed. In order to describe the deformation characteristics of frozen saline sandy soil, an elastoplastic incremental constitutive model is established based on the test results. The proposed model considers the plastic compressive, plastic shear and breakage mechanisms by adopting the non-associated flow rule. The breakage mechanism can be reflected by an index related to the initial, current and ultimate grain size distributions. The hardening parameters corresponding to compressive and shear mechanisms consider the influence of particle breakage. Then the effect of particle breakage on both the stress–strain and volumetric strain curves is analyzed. The calculated results fit well with the test results, indicating that the developed constitutive model can well describe the mechanical and deformation features of frozen saline sandy soil under various stress levels and stress paths. In addition, the strain softening/hardening, contraction, high dilation and particle breakage can be well captured.

     

Dilative behavior of kaolinite under drained creep condition

Acta Geotechnica - This paper studies the dilative behavior of clay during drained creep along triaxial tests under constant mean effective stress, where the volumetric strain is caused by the sole...     

<Superscript>57</Superscript>Fe Mössbauer spectroscopy,X-ray single-crystal diffractometry,and electronic structure calculations on natural sinhalites

Natural sinhalites, MgAlBO_4, from the Ratnapura District, Sri Lanka, and from Bodnar Quarry near Hamburg, Sussex Co., New Jersey, USA, have been characterized by ⁵⁷Fe Mössbauer spectroscopy, electron microprobe, X-ray single-crystal diffractometry and by electronic structure calculations in order to determine the oxidation state and site occupancy of iron in the sinhalite structure. The samples contain about 3.35 and 1.46 wt% of total iron oxide, respectively. The structure refinement is successful and reproduces the total iron content provided that the substitution of Mg²⁺ by Fe²⁺ on the M2 position only is assumed. The ⁵⁷Fe Mössbauer spectra at 77, 293, 573 and 773 K can be resolved into two doublets with hyperfine parameters common for octahedrally coordinated high-spin Fe²⁺. There is no evidence for iron in the tetrahedral site. Electronic structure calculations in local spin density approximation yield hyperfine parameters for Fe²⁺ on the M2-site at 0, 293, 573 and 773 K in quantitative agreement with experiments. Calculated spectroscopic properties for Fe²⁺ on the M1-site are at variance with the experimental data and, thus, indicate that substitution of Al³⁺ by Fe²⁺, if occurring at all, must be accompanied by considerable local expansion and distortion of the M1-octahedron.     

花岗岩型铀矿勘查中航放信息的提取与综合

采取线性与非线性的航放信息提取方法相结合的方式,对桃山地区的航空放射性测量数据进行了处理,在很大程度上有效地提取出与花岗岩型铀矿化密切相关的航放异常信息,建立了花岗岩型铀矿的航放找矿标志,并运用成矿有利度法完成了该区铀成矿潜力评价。已知铀矿含矿单元的正判率达86.4%,表明所建立的找矿标志及评价模型可靠,可用于未知区的铀成矿远景预测。     

黄河冲积层静止土压力系数原位测定与分析

静止土压力系数K0与其他物理力学性质相互制约,变化特征复杂,加之试验条件、理论假设条件不同,表达形式多样,结果迥异。依托济南地铁工程勘察,采用原位土体水平压力测定仪（KSB）对济南西北部黄河厚冲积层现场测试,将测试结果与原位旁压试验、室内侧压力仪K0试验结果,以及考虑黏性土内摩擦角、塑性指数的K0计算公式进行对比,分析表明：KSB测试结果以指数形式插值推算原位静止土压力系数更优;20 m深度范围内黄河冲积层黏性土可近似为正常固结饱和状态,K0介于0.4～0.7之间并随埋深减小,而Jaky公式计算值偏高,室内土工试验K0值偏低;以固结快剪内摩擦角 或等效内摩擦角 修正Jaky公式的计算结果更接近KSB实测值。     

Risk assessment of heavy metals in topsoil along the banks of theYangtze River in Huangshi,China

High concentrations of heavy metal in farmland threatens food production and human health. Our study assesses soil quality and the distribution of Cd, Cr, Cu, Zn, Pb and Ni, to identify possible sources of heavy metals along the banks of the Yangtze River in Huangshi. Heavy metal concentrations of 22 topsoil samples were measured using the inductively coupled plasma mass spectrometry instrument and data was analyzed by multivariate statistic approaches. Heavy metal contamination risk assessment was performed using a combination of the Nemerow multi-factor index method, the Hakanson potential ecological risk index method and the Muller index of geo-accumulation method. These methods determined similar results indicating that cadmium (Cd) poses a health risk to residents at the study site while Cr, Cu, Zn, Pb and Ni do not. The Nemerow multi-factor index method demonstrated that 18 samples were heavily polluted, three moderately polluted and one lightly polluted. The Muller index of geo-accumulation method found ten samples were moderately to strongly polluted by Cd, five were moderately polluted, six were lightly to moderately polluted and one was lightly polluted. The Hakanson potential ecological risk index method proved six samples were strongly polluted, seven were moderately polluted and nine were lightly polluted. Since our sampling sites were all in agricultural lands, we recommend the potential ecological risk index method as the most effective given it not only considers the range of pollutants contributing to soil pollution but factors in heavy metals toxicity. We are apt that the source of the high concentrations of Cd found in topsoil is derived from alluvial sediments upstream of the Yangtze River with a high percentage of residual speciation and a low percentage of exchangeable speciation distribution of Cd. This in turns indicates that a high concentration of Cd in soil had little impact on the natural environment. However, 31.9% of the iron-manganese oxides bound speciation indicating that such levels of Cd in soil would be potentially hazardous to the crops, particularly if exposed to a reductive condition.     

海上复杂断块油田储层流动单元研究与应用——以北部湾A油田A1/A5断块为例

开展海上复杂断块油田储层流动单元研究对刻画储层连通程度、剩余油的分布情况有着十分重要的实际意义。以北部湾A油田A1/A5断块为例,首先对复合砂体内单砂体的识别来建立流动单元研究的精细地质格架,然后结合断层封闭性、隔夹层分布、砂体接触关系所形成的渗流屏障进行流动单元划分。利用主成分分析和相关性分析的方法进行参数优选,确定孔隙度、泥质含量、渗流系数作为研究区流动单元分类的主要参数,并通过神经网络聚类分析将流动单元分为3类。在单井、剖面、平面流动单元展布研究的基础上,运用截断高斯模拟方法建立流动单元三维地质模型。结果表明:Ⅰ类流动单元具有最好的储渗能力,所钻油井累计产量比较高,但分布范围局限,成土豆状分布于水下分流河道中心部分;Ⅱ类分布范围最广,储渗能力较好,分布在水下分流河道微相中,剩余油分布较多,通过调整挖潜可以开发其生产潜力;Ⅲ类大多成条带状分布,主要位于水下溢岸砂沉积部位,储渗能力最差,产量很低,其开发潜力也比较差。