某近城大型露天矿山可持续发展策略#br#

随着城镇化建设深入，近城露天矿山的开发与城市发展之间面临诸多问题，诸如土地空间约束、环保政策趋紧、次生地质灾害等严重影响区域的可持续发展。在实践中，矿山的一些做法虽然取得了一定成效，但仍然存在着家底不清、目标不明、缺乏系统性规划等缺陷，难以实现矿山与城市的协调发展。为此，以某近城大型露天矿山为例，运用SWOT分析法，综合分析其优劣势、存在的机遇与挑战，并提出相应的发展策略。通过矿山废弃物资源化再利用，提高资源的利用效率，解决资金缺口，提升土地的价值，化解矿业开发与城市发展之间的矛盾，实现矿业开发的经济效益、生态效益和社会效益的统一。     

Synthesis and Characterization of Pr0.6-xNdxCa0.4FeO3-δ with Pechini Method

Pr0.6-x NdxCa0.4 FeO3-δ （ x = 0.0, 0.2, 0.3, 0.4, 0.5, 0.6） were synthesized using Pechini method. A number of studies were conducted concerning composition, specific area, crystalline structure and microstructure of the samples by means of FT-IR, BET, XRD TG-DTA and SEM. The results show that all the samples with different doping amounts of Pr^3＋ and Nd^3＋ on A-site are fine dispersed, and mean particle size less than 100 nm. The powders have good sinterability, and the relative density is 95% after sintered at 1200 ℃ for 2 h. It is found that all specimens are entirely single phase solid solutions with orthorhombic perovskite structure, the stable perovskitetype phase is formed completely after calcination at 900 ℃.     

天然气产业链下游市场风险评价模型探讨

随着我国天然气主干管网的逐步形成，天然气产业链下游市场正在进入快速成长阶段，建立风险预警系统的重要性开始显现，而风险评价模型是其基础工作之一。文章在天然气产业链下游区域市场风险评价指标体系的基础上，综合运用层次分析法和灰色系统理论，建立了对天然气产业链下游区域市场风险评价的模型，并以各区域市场的用气量占全国总用气量的比重为权重，建立起完整的市场风险评价模型，可为评价天然气产业链下游市场整体市场风险时参考。     

空间数据立方体的物化视图选择方法研究

针对决策支持系统(DSS)中集成空间分析能力的应用趋势，研究基于空间数据仓库的一种决策分析工具——空间在线分析处理(Spatial OLAP)，拟解决影响空间OLAP在线响应的瓶颈难点——空间数据立方体的物化问题。首先系统地提出空间OLAP的模型，然后对现有空间度量物化视图选择方法进行改进，提出了双向空间Greedy算法。实验证明．该算法在降低选择时间和求解质量两方面具有更好的表现。     

协作学习模式在计算机实验教学中的探索

通过建立计算机开放性实验室,设计各种开放实验,并结合协作学习的模式,为学生创造一个良好的学习与实践环境,以提高学生计算机方面的动手能力及与人协作的能力。阐述了协作学习模式在开放实验中的操作方式,协作学习网络平台的建设,并提出了几种开放实验室的建设及管理方法。     

重复压裂气井产能模拟研究

由于重复压裂气井原有裂缝的失效程度难以评价。导致重复压裂气井的产能预测常常有很大的误差。为此，根据重复压裂气井的压前产量和舍水率，拟合了原有裂缝的有效率，在考虑新裂缝和原有裂缝共同作用的情况下，建立了气、水两相平面二维的裂缝-油藏数学模型，通过对模型的数值求解，对重复压裂气井进行了产能评价。研究表明，在考虑新、老裂缝共同作用下的产能评价方法，能更为准确地预测重复压裂后的生产动态情况，对压裂时机的确定、压后经济效益的预测都具有重要的指导意义。     

Grain Growth Behavior of 5Cr21Mn9Ni4N Steel Micro-Alloyed by Rare Earth

Grain growth behavior of 5Cr21Mn9Ni4NRE steel was experimentally studied at various solid solution treatment temperatures and holding for different times. The experimental results show that the 5Cr21Mn9Ni4NRE steel has the feature of sharp austenite grain coarsening after solid solution treatment at the temperature above 1150 ℃. RE added in the steel has the benefit to restrain grain growth and increase grain growth activation energy.     

PMMA／PBA乳胶IPN阻尼材料的研究

用乳液聚合方法合成了一系列的互穿聚合物网络，其中包括：ＰＭＭＡ／ＰＢＡ和Ｐ（ＭＭＡ－ｃｏ－ＰＭＡ）／ＰＢＡ乳胶互穿聚合物网络（ＬＩＰＮ），ＰＭＭＡ／ＰＢＡ乳胶双向互穿聚合物网络（ＬＢＩＰＮ）以及ＰＭＭＡ／ＰＢＡ界面交联互穿聚合物网络（ＩＣＬＩＰＮ）。动态力学谱和拉伸试验结果表明：（１）ＰＭＭＡ／ＰＢＡ互穿聚合物网络的两组分相容性和阻尼性能可通过ＭＭＡ和ＰＭＡ共聚来改善；（２）双向互穿技术是一种行之     

我国石油天然气企业安全监管博弈分析

采用经济博弈论分析了石油天然气企业的安全监管问题。根据石油天然气企业的特点，建立了政府安全监管部门和石油天然气企业之间的博弈模型，同时建立了企业内部监管机构和一线操作员工之间的博弈模型，分别求解了两个博弈模型，得到了各自的最优策略概率。分析了石油行业的安全形势，提出了相关建议。     

Why are Websites co-linked? The case of Canadian universities

This study examined why Websites were co-linked using Canadian university Websites as the test set. Pages that co-linked to these university Websites were located using Yahool. A random sample of 859 co-linking pages (the page that initiated the co-link) was retrieved and the contents of the page, as well as the context of the link, were manually examined to record the following variables: language, country, type of Website, and the reasons for co-linking. The study found that in over 94% of cases, the two co-linked universities were related academically; many of these cases (38%) showed a relationship specifically in teaching or research. This confirms results, from previous quantitative studies, that Web co-links can be a measure of the similarity or relatedness of sites being co-linked and that Web co-link analysis can thus be used to study relationships among linked Websites.