东亚季风区最近1000 a石笋δ~(18)O空间变化特征及气候意义研究

利用重庆市丰都水鸣洞石笋NSM03精确定年数据和δ~(18)O数据建立的高分辨率石笋记录,结合其他已经发表的亚洲季风区石笋氧同位素记录,探讨洞穴石笋δ~(18)O值过去1 000 a的空间变化特征以及指示的气候环境意义.结果显示:亚洲季风区石笋δ~(18)O值过去1 000 a在空间上呈现出与大气降水δ~(18)O值相似的纬度效应和海陆效应,石笋δ~(18)O值沿水汽输送路径不断衰减,逐渐变轻,表明印度洋是中国季风降水的主要水汽源区;水鸣洞NSM03石笋记录与南亚季风区瓦什卡洞的WBS石笋记录以及中国藏南波密-林芝地区的树轮记录存在明显的相关关系,也进一步地表明中国东部季风区的水汽主要来自印度洋;亚洲季风区石笋δ~(18)O记录在过去1 000 a的变化趋势基本一致,但是中国东部季风区降水变化存在很大的空间差异,这表明季风区石笋δ~(18)O记录不一定都能指示当地降水量的变化;因此,中国季风区石笋δ~(18)O记录主要指示是东亚季风环流的信息,当东亚季风环流强的时候,季风区石笋氧同倍数偏轻;反之亦然.     

中世纪暖期和现代暖期中国季风降水时空模式及其机制

IPCC第五次评估报告认为中世纪暖期(950—1250 A.D.)和现代暖期(20世纪增温)存在具有高可信度.气象观测结果显示20世纪中期以来的显著增温时期,中国降水变化呈现典型的"南涝北旱"两极模式.然而,这一模式与中世纪暖期代用指标重建降水所揭示的"南干北湿"模式存在显著差异,且这一差异的动力学机制亦不明确.继承大气降水氧同位素(δ~(18)O)的中国石笋δ~(18)O记录是描述水循环演变历史信息的理想天然示踪剂.本文将北京石花洞(中国北方)和贵州董哥洞(中国南方)石笋δ~(18)O记录进行对比,基于δ~(18)O-降水-大气环流信号之间的机理联系,解析中世纪和现代暖期大气降水时空模式及其机制.结果显示中世纪暖期石花洞石笋δ~(18)O值显著负偏,指示亚洲夏季风增强,雨带北移,印度洋远源水汽输送增加,而南方洞穴石笋δ~(18)O值相对正偏,指示降水减少或者蒸发加强,局地环流降水增加.在中世纪暖期,洞穴记录对比结果呈现与其他指标重建结果一致的"南干北湿"模式. 20世纪增温时期,石花洞与董哥洞石笋记录均显示δ~(18)O值正偏过程,指示夏季风减弱,雨带南移,北方降水减少;南方降水则由近源水汽输送所控制.研究结果暗示中世纪暖期亚洲夏季风增强可能是气候自然变率的结果,而现代暖期季风减弱则可能与人类活动影响下的海温异常有关.     

福建玉华洞降水、滴水和新生碳酸盐δ~(18)O传递及环境意义

为探究福建玉华洞石笋δ18O的气候环境指示意义,于2011年7月~2013年12月,在将乐县天阶山逐月采集大气降水以及玉华洞3个滴水点和相对应的3个新生碳酸盐沉积物的样品,并进行氢氧同位素测试,分析δ18O在大气降水—洞内滴水—新生沉积物的传递过程及其变化规律.结果表明:3个滴水点的δD和δ18O均分布在当地大气降水线(δD=8.87δ18O+17.59(R2=0.97))附近,表明滴水的δD和δ18O体现了当地大气降水δD和δ18O的平均水平;沉积物δ18O的变化范围小于相对应的滴水δ18O变化范围,更小于洞外大气降水,但3者都呈现出夏秋季偏轻、冬春季偏重的季节性变化趋势;与逐月大气降水量对比发现,沉积物δ18O受月"降雨量效应"影响较少,沉积物δ18O主要受冬夏季降水水汽源地季节性差异的影响.总体而言,玉华洞沉积物δ18O值存在较明显的季节特征,其波动较好的继承了当地大气降水信息,玉华洞石笋δ18O可以用来重建季节性高分辨率的古气候记录.     

石笋碳同位素在古环境研究中的应用

在同位素平衡条件下洞穴上覆不同植被类型对石笋碳同位素组成影响最大,可以用石笋δ~(13)C记录重建C4/C3植被变化。C4较C3植被在暖干气候条件下更具生长优势,而一些研究中石笋δ~(13)C值偏正记录的C4/C3植被高比值与冷干气候条件相对应,似乎有待商榷。石笋δ~(13)C记录会滞后于δ18O记录,并且这种滞后有可能在记录冷事件方面表现更明显。非平衡分馏条件下的非生物因素会和生物因素叠加在一起影响石笋碳同位素组成变化,故在用石笋δ~(13)C记录解释气候变化之前,一定要先准确地识别出非生物因素。未来石笋碳在古环境中的应用还需借助模型定量化评估影响石笋碳同位素组成因素为突破点。     

植被截留对降水同位素分布的试验研究

植被截留对于探究小流域降雨空间变化原因以及深入理解产流机制具有重要的意义.本文通过对长江中下游小流域梅雨降水事件的林外降水和贯穿降水水样的稳定同位素(δ~(18)O和δ~2H)进行分析,探究贯穿降水同位素时空变化原因.通过拟合林外降水的δ~(18)O和δ~2H得到和睦桥流域梅雨事件大气降水线,其斜率和截距接近全球大气水线,但与中国东部季风区的大气水线存在明显的差别,主要是受采样方法、下垫面条件、气候环境和降水类型的综合作用.降水事件中的贯穿降水比林外降水的氘盈余平均值高,这可能与植被的截留以及强烈的蒸发有关.林外降水和贯穿降水的稳定同位素在时间尺度上的变化存在着明显的不同,总的来说贯穿降水相对更加贫化,这可能由蒸发分馏和雨强共同影响.贯穿降水的同位素展示明显的空间变化,主要由植物截留以及流域地形共同影响.     

石笋Mg/Ca比值记录的三峡库区小冰期气候变化

利用采自三峡库区水鸣洞石笋（NSM03）的测年数据、微量元素Mg/Ca比值为气候环境指标,并结合石笋δ18O记录分析三峡库区小冰期时期的气候变化。研究结果显示Mg/Ca值,在AD1280开始迅速减小,并持续至AD1300,石笋δ18O记录也显示在AD1280-1300期间明显快速偏重,表明季风迅速减弱,降水持续减少,库区进入小冰期。石笋微量元素比值记录表明,在小冰期时期内部存在明显的降水波动情况,尤其是在AD1400-1650期间,微量元素比值出现大幅度的震荡,表明季风降水在这一时期处于频繁波动期。     

贵州双河洞海洋同位素阶段11期石笋碳氧同位素记录及古环境意义

采用铀系定年法对双河洞石笋SW01进行年代测定及碳、氧同位素分析,以探讨石笋形成时的古环境信息。结果表明,石笋顶部沉积年代在海洋同位素阶段11期,山王洞形成年代在远早于海洋同位素阶段11期(MIS11)阶段。石笋δ~(18)O值为-8.85‰～-8.39‰,变化趋势与三宝洞同时期石笋SB-14相一致,但值略重。δ~(13)C阈值为-3.89‰～-2.55‰,意味着地表植被以C4植物为主,气候较干旱。结合MIS11阶段的气候特点,推断山王洞区域在MIS11阶段后期气候温暖且相对干燥,降雨量逐渐减少,大气降水量存在旋回性。     

东江下游大气降水氢氧同位素特征及水汽来源

大气降水是水循环系统的主要输入源,其氢、氧稳定同位素组成(δD、δ~(18)O)受区域气象、地理等因素变化影响较大,可以对环境变化做出快速、及时的响应,是研究全球和局地水循环特征的重要技术手段。东江流域地处我国珠江三角洲,季风环流通过影响水汽输送场的分布控制降水的时空分配。为研究区域降水成因及机理,本文采集并测定东江流域下游地区2017年逐日降水样品中δD、δ~(18)O,以月为研究时间尺度,分析其与气温、降水量之间的关系;利用HYSPLIT后向轨迹模式追踪降水气团的传输路径,进一步探讨区域降水的水汽来源及输送状况。结果表明,研究期间降水样品中δD的变化范围为-105.10‰～+9.98‰,雨量加权平均值为-57.88‰;δ~(18)O的变化范围为-14.80‰～-0.55‰,雨量加权平均值为-8.61‰,局地大气降水线为δD=8.60δ~(18)O+16.15(R~2=0.99)。月尺度下δ~(18)O最高值出现在1月份,为-3.47‰,最低值出现在8月份,为-10.17‰。δ~(18)O与气温、降水量均呈显著负相关关系,表现"反温度效应"和"降水量效应"。太平洋水汽带来的降水δ~(18)O、δD偏高,印度洋水汽带来的降水δ~(18)O、δD偏低,而南海降水气团中δ~(18)O、δD则随季节的不同而改变,表现为夏、秋两季明显较春季贫化,存在明显"降水同位素环流效应"。     

小冰期内部1510-1710AD时段石笋δ^18O变化趋势及驱动机制探讨

该文利用重庆丰都水鸣洞石笋NSM03高精度230Th年代数据和δ^18O值建立了三峡库区小冰期内部1510-1710AD这一时段的石笋氧同位素时间变化序列,研究结果显示在这两百年间,NSM03石笋δ^18O曲线呈高频变化,δ^18O值在1510-1670AD年相对偏负,之后δ^18O持续偏重,在1610年左右达到最大值,对应于前人研究的＂明末弱季风＂这一事件,而在1638AD之后又持续偏轻,显示了东亚季风由偏强到弱,再持续强盛的变化趋势。通过对NSM03石笋δ^18O的功率谱分析,发现石笋δ^18O记录在此期间存在25 a、5 a和3 a周期,表明这一时期重庆地区气候变化主要受控于太阳活动变化,同时受到ENSO事件的影响。     

新仙女木事件内部百年尺度弱季风事件的龙腑宫洞石笋记录

基于湖北省神农架龙腑宫洞一支石笋(LFG21)7个U/Th年龄和461组氧、碳同位素数据,建立了末次冰消期12.42~10.53 ka B.P.平均分辨率达3 a的亚洲夏季风强度演化序列.LFG21石笋δ~(18)O详细记录了新仙女木事件(YD)期间的季风突变细节,揭示了YD事件内部的不稳定性.在YD事件结构特征和转型模式上,石笋记录与格陵兰冰芯δ~(18)O记录具有良好的一致性,支持北高纬驱动机制以及高低纬之间的气候联系.其中,在~11.71 ka B.P.氧、碳同位素明显正偏,δ~(18)O从-8.6‰快速正偏至-7.9‰,δ~(13)C从-7.4‰快速正偏至-6.0‰,指示YD内部存在百年尺度的弱季风事件,持续时间为~200 a.这些特征与南京葫芦洞石笋δ~(18)O记录H1事件的内部结构和转型特征十分相似,暗示两者很可能受到同一驱动机制的影响.通过高、低纬地质资料的对比研究和波谱分析,本文认为YD内部百年尺度季风突变事件可能与热带大洋水汽输送变化导致的亚洲季风区水文循环异常以及太阳活动密切相关.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with