末次冰盛期以来东北地区霍拉盆地湖泊沉积物记录的C3/C4植被演化

利用气相色谱-质谱（GC-MS）联用技术对我国大兴安岭北部霍拉盆地湖泊沉积物进行了有机分子地球化学分析,检测出了丰富的正构烷烃。本研究主要讨论了正构烷烃的分布特征及其长链正构烷烃的单体碳同位素组成,结合AMS ¹⁴C年代数据,重建中国东北大兴安岭地区末次冰盛期以来的古植被及古气候变化。正构烷烃分布特征表明,末次冰盛期以来,霍拉盆地湖沼沉积物长链正构烷烃呈现明显的奇碳优势,主峰碳主要为nC₃₁,指示有机质主要来源于陆生高等植物,且草本植物输入占优势,木本植物输入丰富。陆生高等植物来源的长链正构烷烃单体稳定碳同位素的记录显示,末次冰盛期晚期以来古莲剖面沉积物长链正构烷烃（nC₂₇、nC₂₉和nC₃₁）稳定碳同位素整体偏负;此外,利用二元模式估算了C₃/C₄植物相对生物量,结果表明,自末次冰盛期以来我国东北大兴安岭地区C₃植物占绝对优势,然而在全新世大暖期C₄植物生物量呈现明显扩张趋势,这表明气候变暖对C₄植物量的增加有重要影响。

     

Characteristics of B,Zn and Se in stream sediments of Tanzania and their agricultural applications: Based on 1∶1000000 geochemical survey

Tanzania is located in eastern Africa with a predominantly agricultural ecomomy, the potential for developing and utilizing cultivated land are promising, but scientific guidance is required. B, Zn and Se are essential micronutrients for plants and human body with crucial biological functions, in particular, Se is significant for human health and considered as “the king of anti-cancer”. As these elements required by human or plants are mainly absorbed from soil directly or indirectly, therefore,...     

1999—2009年新疆能源消费碳排放的因素分解及实证研究

从影响因素角度用LMDI分解方法对新疆1999—2009年的碳排放进行研究。结果表明:能源结构和能源强度对新疆人均碳排放增长起抑制效应,且能源强度的抑制效应大于能源结构的抑制效应;产业规模和人口规模对新疆人均碳排放增长起拉动效应,且产业规模的拉动效应大于人口规模的拉动效应。能源强度和能源结构的抑制效应难以抵消由产业规模和人口规模拉动的新疆人均碳排放的增长。在实证研究结果的基础上提出了相应的政策建议。     

基于遥感和InVEST模型的白龙江流域景观生物多样性时空格局研究

以甘肃白龙江流域为例,结合遥感、GIS技术和InVEST模型,从景观地理学角度选取区域生境质量、植物净初级生产力和景观状态指数为评价指标,构建区域景观尺度上生物多样性空间格局综合评估方法,并在栅格像元尺度上开展白龙江流域景观生物多样性时空变化特征分析。结果表明：白龙江流域景观生物多样性空间格局差异显著,其生物多样性高值区主要集中在自然保护区和林业管护区,低值区主要分布在舟曲-武都-文县的白龙江两岸及其以北区域、宕昌县岷江沿岸、高寒稀疏植被区和高山积雪-裸岩区。1990~2010年,流域景观生物多样性较为丰富,整体呈现不断增长的趋势,个别局部区域减弱,其增长区主要体现在生态工程实施区和林业管护区,减少区多分布在人类活动频繁的城乡农耕区和灾害多发区。     

基于城市扩张的动态选址模型——以深圳垃圾转运站选址为例

现有的许多选址模型研究,主要集中在对选址算法的改进,而忽略了城市作为复杂地理系统所具备的不确定性和动态发展性对选址结果的影响。这往往导致最终的选址结果在设施投入使用后,无法满足新的需求甚至出现不适应新环境的情况。本文将基于GeoCA(地理元胞自动机)的城市扩张模型引入到传统的Location-allocation选址模型中,构建一个动态的选址模型框架,探索如何将选址结果建立在动态的、科学的城市形态预测基础上,促使选址结果更具有客观性、先见性和更符合可持续发展观,这也正是本研究的重要意义所在。同时,框架中的许多子模型都能够单独被优化,具有高度的可伸缩性,能够自适应于特定区域的选址要求。     

区域形象系统探索

从阐释区域形象系统的有关概念着手,全面探讨了区域形象系统的基本特性和研究内容,并就区域形象系统理论进行了有益研究。     

关于发展我国地下流体前兆流动观测问题的建议

从主机故障、传感器故障、避雷系统故障、供电系统故障4个方面,对天津流体台网水温观测系统故障事件及其跟踪分析进行讨论,提出规范化的排查思路及记录处理方法,可供兄弟台站作为同类数据跟踪分析工作的参考。     

地温示踪地表暖化过程中的气候变化和城市热岛效应

对日本熊本平原城区和郊区28口观测井温度进行测量,利用一维非稳定水－热流运移方程解析解反演地表温度变化率,同时与研究区域7个气象站气温数据进行对比验证。结果表明：1987－2012年研究区域城区地表温度增加1.51°C,近地表气温增加1.13°C;郊区地表温度增加0.81°C,近地表气温增加0.59°C。研究区域气候变化和城市热岛效应对地表暖化过程的贡献率基本一致,通过对城区和郊区地温进行测量分析,能有效量化区分两者对地表暖化过程的影响。     

关于地质统计学两个问题的研究

变异函数的拟合和计算费用高是目前地质统计学在推广应用中遇到的主要障碍。本文引出一种新的数学方法——线性规划法,基本上解块了变异函数的自动拟合问题;文章根据克里格方程组的结构,推导出一种无需逐块求方程的快速算法,使原来求解克里格估计值的巨大工作量被减少到可以忽略不计,彻底解块了地质统计方法储量计算的费用问题.     

Test and analysis of reinforced concrete (RC) precast shear wall assembled using steel shear key (SSK)

Reinforced concrete (RC) precast shear walls are extensively applied in practical engineering, owing to their fast construction speed. However, because of the transport conditions, RC precast shear walls have to be separated into small wall segments during the factory prefabrication procedure before being assembled on site. Typically, wet-type jointing methods are adopted to link the segments, which is time-consuming and results in unreliable post-pouring area strength. To overcome this problem, the novel scheme of the steel shear key (SSK) featuring steel shear panels and combined fillet and plug welding is proposed. Three RC precast shear wall specimens with different linking strength, termed as weakened SSK wall, standard SSK wall, and strengthened SSK wall, respectively, and an integrated shear wall specimen were designed. Quasi-static cyclic loading was applied to investigate the specimens' dynamic properties. The test results suggest the prefabricated wall segments equipped with SSKs showed reliable stiffness and bearing capacity and were improved in energy dissipation ability, compared with conventional shear walls. As the shear stiffness and number of equipped SSKs increased, the specimens exhibited higher strength, but their ductility and energy dissipation were slightly decreased. Most importantly, the standard SSK wall specimen could achieve satisfactory bearing capacity and deformability and is thus recommended for precast building structures. Finite element method (FEM) models were established to validate the test results, and parametric study analysis was conducted based on the coupling ratio of the SSK walls. Finally, an appropriate coupling ratio range is recommended for practical engineering applications.