巴颜喀拉山东端过去376年来夏季气温变化

巴颜喀拉山地处青藏高原东缘,是长江和黄河上游的分水岭,其生态环境与气候背景变化对下游地区的生态安全具有重要影响,但较短的器测记录限制了对该地区气候变化历史和机制的认识。本文基于巴颜喀拉山东端青海云杉（Picea crassifolia）486年树轮宽度年表,重建了该地区376年的夏季（6月、7月和8月）平均气温变化。结果显示,研究区经历了2个冷期（1724~1789年、1864~1994年）和3个暖期（1637~1723年、1790~1863年和1995~2012年）。经集合经验模态分解（Ensemble Empirical Mode Decomposition,简称EEMD）发现,重建温度序列的年代际和多年代际信号与太平洋年代际涛动（Pacific Decadal Oscillation,简称PDO）和北大西洋涛动（North Atlantic Oscillation,简称NAO）的变化有较好的一致性,表明PDO和NAO可能对研究区夏季温度变化具有重要影响,但具体影响机制需要气候模式来进一步揭示。     

2D modeling of overpressure in a salt withdrawal basin,Gulf of Mexico,USA

This study demonstrates the utilization of 2D basin models to address overpressure development due to compaction disequilibrium in supra-allochthonous salt mini-basins with very high sedimentation rates in the Gulf of Mexico. By properly selecting 2D line sections with moderate stratigraphic resolution, it is possible to predict timing of overpressure development and approximate present-day overpressure distributions in the mini-basin. This study shows that even low resolution models with approximate information on the net-to-gross (sand:shale ratio) can average ±0.4 ppg with a maximum error of 1.0 ppg relative to pressure measurements in sandstones. The models based on age, depth, approximate lithology and an interpretation of complicated salt movement are adequate to evaluate pressure to address issues around trap containment and may be used for preliminary well planning. This study tested the results of overpressure prediction utilizing different stratigraphic resolutions and shows the sensitivity of overpressure modeling to 2D line selection. Also, three models were built to investigate how the permeability of salt welds affects overpressure development in an adjacent salt mini-basin. These results indicate that even a salt weld permeability reduction of 1.5 log mD results in a pressure difference between neighboring mini-basins. Additionally, these models qualitatively reproduced the seismic velocity volume which is supporting evidence that the salt welds in this mini-basin are at least partially sealing.     

小湾水电站坝址区低高程岸坡表生改造特征及机制研究

摘要：小湾水电站坝基、水垫塘边坡及低高程排水洞系统广泛地揭示了低高程岸坡的地质特征。基于现场调查和二维弹塑性有限元分析,深化认识了低高程岸坡表生改造特征：（1）它是在建造和构造改造的基础上进行的：原构造缓倾角节理扩展、错动;陡倾角节理扩展、产状改变以及错动;新生了大量中缓倾角裂隙;表生改造程度向坡内减弱。（2）建立了低高程岸坡表生改造缓裂生成机制模型,分析了其生成过程。（3）在二维弹塑性有限元分析中,基于拉破坏区分布、剪应变和点安全度等指标,分析了低高程岸坡卸荷松弛范围,其中谷底表生改造明显影响深度为6~9m。     

龙门山构造带中段实测剖面的古应力恢复

龙门山逆冲构造带由茂汶断裂带、北川-映秀断裂带和安县-灌县断裂带及其间夹块组成,这一NE向构造带印支期以来遭受了多期构造活动,形成了川西前陆盆地的多套粗碎屑岩记录。本文大致垂直主构造线走向,沿都江堰至耿达剖面进行了断裂滑动分析和古应力恢复。通过9个观测点12组断裂数据的古应力反演,并结合区域热年代学研究成果,获得了龙门山构造带三条主要断裂活动阶段的认识,包括早期NNW向区域挤压、中期SEE向区域挤压、以及晚期NNE、NNW两个方向区域挤压,推测它们依次与秦岭晚造山挤压（T3）、江南隆起挤压与青藏构造域联合（K1）及青藏构造域为主体（K以来）的区域构造控制有关。     

教育绅士化社区：形成机制及其社会空间效应研究

教育绅士化现象已成为深刻影响我国城市居住空间分异的重要因素,以长春市郊区出现的教育绅士化社区为例,对其形成机制及社会空间效应进行深入研究。结果表明：① 在优质教育资源空间分布不均及教育体制改革背景下,私立学校与房地产开发活动在郊区的结合催生出一种新的教育绅士化现象,其实质是由教育资源引发的绅士化现象。② 教育绅士化社区采用“房地产+名校”的模式进行开发,涉及地方政府、房地产开发商、学校以及绅士阶层四大主体。教育绅士化缘于地方政府的征地行为,开发商是物质景观改造的主体,学校则是吸引绅士阶层集聚的关键。③ 教育绅士化社区一方面引导了资本、中产阶层和优质教育资源向郊区的迁移,促进了郊区物质景观及人口、社会经济的升级,并在一定程度上有利于教育公平。另一方面又不可避免地引起了城市人口、社会经济空间的分层和极化。本研究在一定程度上丰富了教育绅士化的研究内容和研究视野,同时对教育、住房以及城市发展政策的制定具有一定启示。     

贺兰山树轮晚材宽度记录中的降水量变化

通过贺兰山地区树木年轮晚材宽度的研究，建立了贺兰山地区最近250年来的树轮晚材宽度年表。与气象观测记录的相关分析结果表明，树木生长与生长季当年5—7月降水量呈明显的正响应，在此年表的基础上重建了贺兰山地区过去250年来5—7月降水量，发现其具有明显的干湿变化，相对干旱年占总年数的52％，相对湿润年占总年数的35．5％，平年为14．5％，旱灾是该地区主要旱涝灾害。谱分析结果显示该地区5—7月降水有明显的2．6、3．5、21．3年的3个准周期。同时贺兰山地区降水量的变化历史可以反映东亚夏季风的变迁历史。     

地震后重建过程中的建筑最低成本分析

震后重建工作中,传统建筑最低成本的分析方法无法平衡成本与建筑需求性关系,造成最低成本下建筑的抗震能力较低。设计震后建筑最低成本分析方法,分析震后建筑成本需求关系,提供建筑成本与需求关系的基本数据;优化IFC建筑标准,定义最低成本指标;对分析因素进行综合设置,平衡价值链上需求关系;分析需求与建筑成本关系,完成震后建筑最低成本分析方法的构建,实现最低成本分析。实验数据表明,设计的建筑最低成本分析方法既能满足需求关系,又能实现建筑成本的最低化分析。     

锥束重建的Smith—Grangeat方法的分析

ＣＴ机、ＳＰＥＣＴ及ＰＥＴ等医疗设备是当前重要的医疗诊断工具，但这些设备都跟某些射互有关，当放射性元素衰变而发射某种射线时，如果它们在４立体角范围内是等概率分布的，则扇形采集比在上方向上有集的效率提高了许多。     

A graph edit dictionary for correcting errors in roof topology graphs reconstructed from point clouds

In the task of 3D building model reconstruction from point clouds we face the problem of recovering a roof topology graph in the presence of noise, small roof faces and low point densities. Errors in roof topology graphs will seriously affect the final modelling results. The aim of this research is to automatically correct these errors. We define the graph correction as a graph-to-graph problem, similar to the spelling correction problem (also called the string-to-string problem). The graph correction is more complex than string correction, as the graphs are 2D while strings are only 1D. We design a strategy based on a dictionary of graph edit operations to automatically identify and correct the errors in the input graph. For each type of error the graph edit dictionary stores a representative erroneous subgraph as well as the corrected version. As an erroneous roof topology graph may contain several errors, a heuristic search is applied to find the optimum sequence of graph edits to correct the errors one by one. The graph edit dictionary can be expanded to include entries needed to cope with errors that were previously not encountered. Experiments show that the dictionary with only fifteen entries already properly corrects one quarter of erroneous graphs in about 4500 buildings, and even half of the erroneous graphs in one test area, achieving as high as a 95% acceptance rate of the reconstructed models.     

Selection of prior distributions and multiscale analysis in Bayesian temperature reconstructions based on fossil assemblages

It is possible to reconstruct the past variation of an environmental variable from measured historical indicators when the modern values of the variable and the indicators are known. In a Bayesian statistical approach, the selection of a prior probability distribution for the past values of the environmental variable can then be crucial and the selection therefore should be made carefully. This is particularly the case when the data are noisy and the statistical model used is complex since the influence of the prior on the results can then be especially strong. It can be difficult to elicit the prior probability distribution from the available information, since usually there are no measured data on the past values of the variable one wants to reconstruct and different reconstructions are typically consistent with each other only at a coarse level. To overcome these difficulties we propose to use a non-informative smoothing prior, possibly in combination with an informative prior, that simply penalizes for roughness of the reconstruction as measured by the variability of its values. We believe that it can sometimes be easier to set an overall prior distribution on the roughness than to agree on a prior for the actual values of the reconstructed variable. Note that by using a smoothing prior one incorporates into the model itself the smoothing step usually done before or after the actual numerical reconstruction. Another idea proposed in this paper is to integrate the reconstruction model with a multiscale feature analysis technique known as SiZer. Multiscale analysis of the posterior distribution of the reconstructed variable makes it possible to infer its statistically significant features such as trends, maxima and minima at several different time scales. While only temperature is considered in this paper, the technique can be applied to other environmental variables.