Porosity and wave velocity evolution of granite after high-temperature treatment: a review

The evolution of porosity and changes in wave velocity in granite after high-temperature treatment has been experimentally investigated in different studies. Statistical analysis of the test results shows that there is a temperature threshold value that leads to variations in porosity and wave velocity. At a temperature that is less than 200 °C, the porosity of granite slowly increases with increases in temperature, while the wave velocity decreases. When the temperature is greater than 200 °C (especially between 400 and 600 °C), the porosity quickly increases, while the wave velocity substantially decreases. The temperature ranges of room temperature to 200 and 200–400 °C correspond to the undamaged state and the micro-damage state, respectively. The results confirm that there is an important link between the variations of physical and mechanical properties in response to thermal treatment. By studying the relationships among rock porosity, wave velocity and temperature, this provides the basis for solving multi-variable coupling problems under high temperatures for the thermal exploitation of petroleum and safe disposal of nuclear waste.     

城市地下空间开发利用地质适宜性三维评价指标体系研究——以杭州市为例

地下空间开发地质适宜性三维评价是合理进行地下空间立体化开发、降低开发地质风险的重要手段,也是当前研究热点。作为地质适宜性三维评价全过程的重要一环,科学合理地建立三维评价指标体系是其能否正确开展的前提基础。通过结合杭州城市地下空间开发面临的地质问题,在系统分析各评价指标对地下空间开发建设影响的特征基础上,以三维视角从地层三维结构等多个方面构建完成了一套具有多层次结构的三维评价指标体系,并采用层次分析方法对评价指标进行了目标权重的计算、一致性检验、排序和分析。该指标体系可划分为5个准则层21个指标层,相较于二维评价指标体系,通过融合三维地质模型和三维空间分析方法,使评价过程中能够考虑更多的评价因子,更好地描绘地下复杂的三维地质环境,丰富了三维评价结果的内涵。基于模糊综合评价方法的杭州钱江新城二期的三维评价应用成果表明,该指标体系为三维地质模型和三维空间分析方法之间的整合提供了有力的指导,为提升三维尺度下的地下空间开发地质适宜性评价精度和准确性提供了有力的支持。     

气溶胶对北京中尺度对流系统影响的数值试验

利用可分辨云模式(WRF),模拟研究了不同气溶胶浓度对北京地区2001年8月23日一次产生强降水和冰雹的对流天气的影响。结果表明,气溶胶浓度的增加不利于对流云的发展,导致地面降水减小,但是对降水结构没有明显影响。气溶胶浓度增加导致云中水成物数浓度和质量浓度均发生变化,其中云水、冰晶和雪含量增加,而雨水、霰和雹含量减小。从云微物理学分析发现,气溶胶浓度减小有利于高层云的形成,云滴有效半径随着气溶胶浓度增加而减小。     

The formation of explosive volcanos at the circum-Pacific convergent margin during the last century

Journal of Oceanology and Limnology - The circum-Pacific convergent margin is known as “the Ring of Fire”, with abundant volcano eruptions. Large eruptions are rare but very disastrous....     

A statistical study on the temporal distribution of ionospheric TEC anomalies prior to M7.0+ earthquakes during 2003–2012

In this paper, we conduct a new statistical study on the temporal distribution of the Global Positioning System Total Electron Content (GPS TEC) anomalies prior to the earthquakes with magnitude M≥7.0 in the global area during 2003–2012 by the method of statistical analysis. The temporal distribution of the ionospheric TEC anomalies prior to the earthquakes with magnitude M≥7.0 is for the first time studied. It has been observed that the ionospheric negative anomalies mainly occur in one week prior to the earthquakes, and only when the magnitude is greater than or equal to 7.6, the ionospheric anomalies will have the greatest probability of occurrence in the afternoon to sunset (i.e. between 12:00 and 18:00 local time). They last for approximate 2 hr, but the chance of detecting the significant enhancement in the ionospheric TEC seems not to be a function of time and there is no clear tendency for positive anomalies. In addition, the relationship of the occurrence rate of pre-earthquake ionospheric anomalies and the magnitude of the earthquake is discussed, and it is found that the observed ionospheric TEC anomalies within several days before the earthquakes are highly likely to be related with the earthquakes because the occurrence rate of pre-earthquake ionospheric anomalies seems to increase slightly with the earthquake magnitude increasing.     

新疆恰瓦克南钛磁铁矿成矿地质条件、控矿因素及找矿预测

恰瓦克南钛磁铁矿位于巴楚断隆的西北段,产于华力西晚期的NWW向构造穹隆NWW向与基底性的NWW向断裂的交汇部位,成矿与麻扎塔格杂岩体中的基性-超基性岩具有直接联系。钛磁铁矿体具有较大的规模,矿体呈层状或似层状,赋矿岩石主要为辉长岩、辉石岩和橄辉岩,矿体均为隐伏矿体,矿石铁品位w(TFe)=10.21%～17.36%,属于低品位磁铁矿床。恰瓦克南钛磁铁矿床与附近的瓦吉里塔格钒钛磁铁矿床具有相似的成矿条件和矿床地质特征,成矿物质主要来源于基性-超基性岩体,基性岩浆的演化促成钛磁铁矿的聚集成矿,而构造穹隆产生NNW向断裂和NEE向断裂的交汇部位则控制着成矿基性-超基性岩的上侵和定位。文章还对进一步的找矿工作进行了预测。     

Effects of timber infill walls on the seismic behavior of traditional Chinese timber frames

This study investigates the enhanced effect of timber infill walls on the seismic behavior of traditional Chinese timber frames. Two 1/2 scaled traditional Chinese timber infill walls(TIWs), two 1/2 scaled timber frames with timber infill walls(TFTIWs) and one 1/2 scaled timber frame(TF) were fabricated and tested under low-cyclic reversed loading. The failure modes, strength, stiffness, and energy consumption capacity of the TIWs and the TFTIWs were obtained, and the effects of the TIWs on the ...     

中国粮食生产效率空间溢出网络及提升路径

现有研究普遍关注粮食生产单元自身资源禀赋以及功能属性,对于经济主体相互作用所产生的外部性研究十分有限。为此,本文在空间引力模型的基础上着重分析网络外部性对粮食生产效率的影响,并以此为逻辑起点进一步探讨网络提升路径以及各空间单元在整体网络中的综合定位与潜力。结果表明,中国粮食生产网络空间溢出效应显著,对粮食生产效率具有明显的促进作用,其实质是规模经营思想在空间维度的扩展,符合近带动远辐射规律,且交通基础设施的互通互联与人口流动是实现网络空间外溢的主要路径。同时,整体网络中共存在4种潜在节点,包括核心控制型、局域核心型、潜力型以及边缘型。未来应充分发挥核心控制型节点的辐射带动作用,加强东西轴带的空间交互影响,实现农业资源技术的跨地域流动与互补。