库尔勒1959-2008年冬季气温及负积温变化特征

利用库尔勒市近50a冬季逐日气温资料,分析了库尔勒冬季日平均气温、最低气温、负积温以及低温持续日数的变化趋势和特征,结果表明：库尔勒冬季平均气温自1985年开始发生增暖突变,最低气温、极端最低气温均在波动中逐渐上升,冬季增温主要体现在最低气温和2月平均气温的显著偏高,冬季气温最暖阶段在20世纪90年代;冬季负积温增暖变化早于冬季气温,冬季≤0℃低温持续日数明显减少,但近8a冬季≤-15℃的低温寒冷日数较20世纪80、90年代有明显增加,从而导致近8a负积温绝对值的增加。     

Multiple sulfur isotope chemostratigraphy across the Permian–Triassic boundary at Chaotian,China: Implications for a shoaling model of toxic deep-waters

Previous studies on multiple sulfur isotopes (³²S, ³³S, and ³⁴S) in sedimentary pyrite at the end-Permian suggested a shoaling of anoxic/sulfidic deep-water contributing to the extinction. This scenario is based on an assumption that the sedimentary sulfur cycle was largely controlled by benthos activity, though a stratigraphic correlation between the sulfur records and ichnofabrics of the sediments at the end-Permian has not yet been examined. We report the multiple sulfur isotopic composition of pyrite in the Permian–Triassic boundary interval at Chaotian, South China. Our data can be generally explained by a mixing of sulfur in sulfide from two different sources: one produced via sulfate reduction in an open system with respect to sulfate and the other produced in a closed system. In particular, the former with the substantially low δ³⁴S (<−40 ‰) and high ∆³³S (up to +0.100 ‰) values was likely produced via water-mass sulfate reduction or via sulfate reduction in oxic sediments with common burrows. The frequent occurrence of small pyrite framboids (mostly <5 μm in diameter) in the Lopingian (Late Permian) Dalong Formation of deep-water facies supports the enhanced water-mass sulfate reduction in an anoxic deep-water mass. The negative ∆³³S values are observed only in the oxic limestones, and no substantial ∆³³S change is observed across the extinction horizon despite of the disappearance of bioturbation. Our results are apparently inconsistent with the previous shoaling model. We expand the model and infer that, when the deep-water was sulfidic and its shoaling rate was high, a substantial amount of hydrogen sulfide (H₂S) was supplied onto the shelf via the shoaling; that resulted in the positive ∆³³S value of the bulk sediments. The observed ∆³³S variation on a global scale suggests a substantial variation in H₂S concentration and/or in upwelling rate of shoaling deep-waters during the Permian–Triassic transition.     

嵌岩桩负摩阻力现场试验与计算方法研究

桩-土剪切位移对桩基负摩阻力发展有重要的影响。在既有研究的基础上,通过桩周土体沉降与桩身应变的监测结果建立了计算桩-土剪切位移量的方法。利用该方法对浅中层桩-土监测数据进行分析,确定了在桩顶自由条件下该试验场地桩-土剪切位移量在4~5 mm;对于深层桩-土没有达到该剪切位移量,负摩阻力则无法发挥至极值。根据负摩阻力的发挥特征,改进了规范中嵌岩桩负摩阻力的计算方法,该方法同时考虑了桩周土竖向有效应力与桩土剪切位移的影响。使用该方法计算的负摩阻力与实测结果较为吻合,获得的下拉荷载能够达到安全与经济的效果,可供工程设计参考、借鉴。     

贵州高原山区正负地形特征及其对人口分布的影响

正负地形可通过源汇过程对水、土资源进行再分配,影响山区的人口分布。获取正负地形数据,运用6个指标和多元逐步回归法,分析贵州高原山区正负地形特征及其对人口分布的影响。研究表明：①贵州高原山区的正负地形结构异质性明显。蚕食度、深切度、平均粗糙度比、形状指标、匀度指数、破碎度的平均值分别为1.07、371m、1.01、3.40、325和3.34,表明正地形被负地形蚕食明显、切入深度大,正、负地形的粗糙度基本相当,正负地形景观斑块呈现形状不规则、面积不均匀的破碎状态。6个正负地形指标中,匀度指数的变异性最大,变异系数为90.43%;平均粗糙度比的变异性最小,变异系数为1.06%;②贵州高原山区的人口分布不均匀性突出。人口累积达到40%时,累积面积百分比为14%;人口累积达到80%时,累积面积百分比约为50%;③6个正负地形指标中,蚕食度和深切度是影响人口分布的主要因素。蚕食度与人口密度呈正相关关系,深切度与人口密度呈负相关关系。研究成果为研究地形条件的人口影响提供补充,并为贵州高原山区人-地关系协调和土地可持续管理提供参考。     

基于Item2Vec负采样优化的专题地图产品个性化推荐方法研究

建立适用于专题地图产品检索的用户偏好推荐模型是提高专题地图质量的有效方式之一,在专题地图产品推荐场景中,存在严重的内容冷启动和评论数据稀疏问题,现有的推荐算法无法为特定类用户推荐不同特征的专题地图产品,导致用户从专题地图中获取偏好信息受到限制。因此,本文构建基于负采样的连续词袋模型和基于Word2Vec的Item2Vec相结合的用户偏好推荐方法,用于专题地图产品推荐。① 计算用户行为日志文件中交互行为数据的隐性评分,以代替专题地图推荐信息流场景中稀疏的用户评论数据;② 基于负采样的连续词袋模型提取目标专题地图的前后地图序列感知特征信息,通过控制正负样本比例为1:2,提升目标专题地图潜在评分的预测精度;③ 通过Item2Vec将带有用户行为特征信息的专题地图映射到向量空间,计算用户对专题地图的相似度矩阵,根据用户偏好程度完成推荐。在构建的专题地图评分实验数据集Thematic CMaps和4个公开验证数据集MovieLens上的测试结果表明:与LFM、Personal Rank、Content Based和SVD 4种传统推荐算法相比,本文所提方法可有效提高潜在评分的预测精度,推荐性能最高达到27.85%;与以霍夫曼采样方式的Item2Vec基础方法和YouTubeNet 2种神经网络推荐算法相比,评分预测精度有一定提高,且推荐性能不断提升,最高达到2.97%和5.78%。以经典算法奇异值分解（SVD）为例,将MovieLens-20M数据集切分后,在数据量不断增大的数据子集中,本文所用方法的评分预测精度和性能均优于SVD方法。     

Deriving 3D coseismic deformation field by combining GPS and InSAR data based on the elastic dislocation model

The density of GPS measurements is usually one of the key issues in resolving 3-D coseismic deformation field from integrating GPS and Interferometric Synthetic Aperture Radar (InSAR) measurements with pure mathematic interpolation methods An approach that combines the elastic dislocation model with the Best Quadratic Unbiased Estimator (BQUE) or a robust estimation method named IGG (Institute of Geodesy and Geophysics) is proposed to reconstruct 3-D coseismic deformation field, in which only a small amount of GPS data is needed to produce a reasonable initial 3-D coseismic deformation. Then the BQUE and IGG are used to weight the InSAR and GPS measurements to avoid computational issues caused by the negative variance problem and to decrease the impact from gross errors. The Wenchuan earthquake is used to test the proposed method. We find that the developed method makes it possible to use only a few GPSs and InSAR data to recover the 3-D coseismic deformation field, which offers extensive future usage for measuring earthquake deformation, particularly in some tectonically active regions with sparse GPS measurements.     

青藏高原西部日土-普兰一带古构造应力值的估算

本文用超显微构造的位错密度法,估算了该地区6次构造事件的古构造应力值。尽管从现在的构造形变特征来看,不同构造事件都是沿近南北方向的伸展或挤压,但其形变强度各不相同,印支运动（晚三叠世）最强,平均差应力值达201MPa,四川运动（白垩纪—早第三纪早期）次之,为183MPa,其它各次构造运动均较弱,阿森特运动（前寒武纪末期）为101MPa,海西运动（早二叠世晚期）为121MPa,燕山运动（晚侏罗世）为130Mpa,喜马拉雅运动（中新世末期以来）为110MPa,加里东运动在本区大部分地方较弱,我们未采集到能反映其构造应力状态的样品。     

东天山康古尔金矿床石英位错构造及其动力学意义

康古尔金矿床形成于脆韧性—脆性剪切变形构造演化过程中。应用透射电镜超微技术分析水热成矿期石英位错构造、位错密度及差应力值有助于加深认识剪切构造条件下的成矿动力学机制。石英位错构造特征反映成矿期构造变形环境为中温—中低温、高差异应力、高应变速率。成矿期构造差应力演化呈明显的脉动性,这种脉动性所形成的“应力地震泵吸”机制对金矿成矿至关重要。     

济阳坳陷构造演化及其大地构造意义

济阳坳陷由负反转盆地、右旋扭张盆地及主动裂谷三个原型叠加而成,并在中、新生代经历了四个演化阶段,三叠纪为板内造山作用阶段,济阳坳陷曾为五条ＮＷ向的以逆冲断层为主的压性构造带占据,早－中侏罗世造山作用结束;晚侏罗世－早始新世为负反转盆地阶段,三叠纪ＮＷ向逆冲断层发生反向伸展;中始新世－渐新世为右旋扭张盆地阶段,ＮＥ,ＥＮＥ向扭张断裂发育,并进而成盆接受沉积,ＮＷ和断裂反向伸展活动受到抑制而渐趋消亡;中新世－全新世为主动裂谷阶段,“拗陷运动”取代“断陷运动”。济阳坳陷构造演化的阶段特征表明了郯庐断裂中、新生代的剪切运动史,即三叠纪右旋剪切,晚侏罗世－早始新世左旋剪切．中始新世－渐新世右旋剪切,中新世－全新世作弱右旋压剪。     

Dislocation parameters of Gonghe earthquake jointly inferred by using genetic algorithms and least squares method

IntroductionOnApril26,1990,anMs=7.0strongewthquakeoccurrednearTanggannofarminnerGonghebasin,QinghaiProvince.Aftertheevent,theSecondCrustalDeformationMonitoringCented,ChinaSeismologicalBureau,immediatelyconductedarelevelingsurveyalongthetwolinesacrosstheearthquakeregioninMayandJuneof1990,thereweretotally27levelingpoilltsreoccupied.Alongwiththelastpre-earthquakelevelingsurveyin1978,abigupliftwiththemaximum345mmatDH20aswellasasmallsubsidencewiththemaximum45.1mmatDH16havebeendetected(Figur…