动荷载作用下海底粉土的孔压响应及其动强度

本文选用近海分布较广的粉土为研究对象 ,利用室内动三轴试验结果 ,找出动荷载作用下粉土的动应力应变关系 ,分析模拟波浪荷载作用下粉土中的孔压响应、临界循环次数 ,确定波浪作用下粉土的应力状态、破坏临界循环次数 ,判断不同深度处的粉土发生液化的可能性及发生液化所需要的时间 ;研究粉土在动荷载作用下的强度降低 ,为海上工程设计和施工提供科学依据。     

参考数据集对Argo剖面浮标盐度观测资料校正的影响

国际Argo计划采用新颖的Argo剖面浮标来监测全球大洋中上层的变化,对浮标盐度观测资料进行质量控制是非常重要的。本文采用历史水文观测资料集得到的温-盐度(-S)关系,并利用Wong等人开发的WJO延时模式盐度校正方法,对电导率传感器出现漂移、偏移等故障的Argo剖面浮标盐度资料进行校正。对影响校正结果的历史水文资料集(或参考数据集)的选取进行了初步研究,并在不同的海区进行试验。结果表明,选取合适的参考数据集可以提高盐度校正的精度。     

台湾东北海域冷水块的特征

根据海洋调查历史资料 ,对台湾东北海域冷水块的时空分布、结构、特点进行分析 ,主要结果如下 :(1 )首次利用卫星跟踪漂流浮标的轨迹 ,佐证冬季该冷水块的存在。 (2 )鉴于该冷水的重要性 ,建议对它给予称谓 ,暂定名为“彭花棉”冷水块。 (3 )该冷水块是黑潮次表层水涌升的结果 ,是黑潮对我国近海海洋环境影响的典型实例之一。 (4)该冷水块具有低温、高盐、高密、低氧、高磷、高硅和高氮等特性     

β-1, 4-半乳糖基转移酶抑制剂的研究进展

β-1,4-半乳糖基转移酶(β-1,4-GalT)抑制剂的研究是当今糖化学和糖生物学的前沿研究领域之一。本文就β-1,4-GalT抑制剂(包括供体类似物、受体类似物、过渡态类似物)的设计、合成及活性评价诸方面予以综述。     

滇西北兰坪地区金顶超大型铅锌矿床架崖山-北厂 矿段岩石地层特征

详细描述了滇西北兰坪金顶矿区架崖山-北厂主矿段露采剖面的岩石地层学特征。架崖山-北厂矿段出露正常沉积岩和非正常沉积岩两大岩石系列,分别由灰白色白云质灰岩、黑色泥晶灰岩、青灰色泥灰岩、杂色泥质粉砂岩、砖红色粉砂岩、红色膏溶角砾岩和浅灰色钙质砂岩、灰褐色灰岩角砾岩、杂色垮塌角砾岩组成。空间上以非正常沉积岩系列灰褐色灰岩角砾岩和浅灰色钙质砂岩为中心,正常沉积岩系列灰白色白云质灰岩、黑色泥晶灰岩、杂色泥质粉砂岩、青灰色泥灰岩和红色膏溶角砾岩分布于其周围。灰褐色灰岩角砾岩和浅灰色钙质砂岩构成了金顶矿区的2种主要矿石类型,二者空间上密切共生,近直立的灰岩角砾岩分布于近水平的钙质砂岩层的下部,构成似“蘑菇”状的几何形态。架崖山-北厂矿段岩石地层学的特征揭示了兰坪金顶铅锌矿泥底辟机制的成因特点,为矿区勘查和外围寻找金顶式矿床提供了新恩路。     

中朝地台东北缘地区的地震层析成像

根据中朝地台东北缘地区 (东经 1 1 7°0 0′— 1 2 6°0 0′ ,北纬 36°0 0′— 44°0 0′) 1 980— 1 997年的 380 0 0余条P波走时数据 ,利用正交投影法重建了该区地壳和上地幔的三维速度结构 .通过分析及同人工地震测深剖面的详细对比 ,证明了成像结果的可靠性 .结果表明 :中朝地台东北缘地区地壳上地幔介质存在显著的横向不均匀性 ,直至 1 2 0km深度处依然明显 ;地壳上部的速度图像清楚地反映了不同岩石单元的分布与该区不同性质的基岩分布基本吻合 ;从上、中地壳的速度图像中发现了研究区存在海城、朝阳、义县、丹东南、唐山等几个低速异常区(即速度逆反层区 ) ,其中海城、唐山、朝阳等地区的壳内低速层已由深地震测深资料所证实 ;研究区陆地发生的几次强震均发生于壳内低速层上方的高速脆性介质内 ,而渤海发生的强震 ,此现象不明显 ,但都发生于横向介质速度显著突变的位置 ;在地壳不同深度上发现了普兰店至山海关横跨渤海的北西向低速异常带 ;地震层析二维速度图像与深地震测深资料的对比表明 ,研究区利用地震层析成像技术 ,在一定条件下可以获得与人工地震测深相似的效果     

Optimum multiple tuned mass dampers for structures under the ground acceleration based on the uniform distribution of system parameters

The five MTMD models, with natural frequencies being uniformly distributed around their mean frequency, have been recently presented by the first author. They are shown to have the near‐zero optimum average damping ratio (more precisely, for a given mass ratio there is an upper limit on the total number, beyond which the near‐zero optimum average damping ratio occurs). In this paper, the eight new MTMD models (i.e. the UM‐MTMD1～UM‐MTMD3, US‐MTMD1～US‐MTMD3, UD‐MTMD1 and UD‐MTMD2), with the system parameters (mass, stiffness and damping coefficient) being, respectively, uniformly distributed around their average values, have been, for the first time here, proposed to seek for the MTMD models without the near‐zero optimum average damping ratio. The structure is represented by the mode‐generalized system corresponding to the specific vibration mode that needs to be controlled. Through minimization of the minimum values of the maximum dynamic magnification factors (DMF) of the structure with the eight MTMD models (i.e. through the implementation of Min.Min.Max.DMF), the optimum parameters and values of Min.Min.Max.DMF for these eight MTMD models are investigated to evaluate and compare their control performance. The optimum parameters include the optimum mass spacing, stiffness spacing, damping coefficient spacing, frequency spacing, average damping ratio and tuning frequency ratio. The six MTMD models without the near‐zero optimum average damping ratio (i.e. the UM‐MTMD1～UM‐MTMD3, US‐MTMD1, US‐MTMD2 and UD‐MTMD2) are found through extensive numerical analyses. Likewise, the optimum UM‐MTMD3 offers the higher effectiveness and robustness and requires the smaller damping with respect to the rest of the MTMD models in reducing the responses of structures subjected to earthquakes. Additionally, it is interesting to note, by comparing the optimum UM‐MTMD3 with the optimum MTMD‐1 recently investigated by the first author, that the effectiveness and robustness for the optimum UM‐MTMD3 is almost identical to that for the optimum MTMD‐1 (without inclusion of the optimum MTMD‐1 with the near‐zero optimum average damping ratio). Recognizing these performance benefits, it is preferable to employ the optimum UM‐MTMD3 or the optimum MTMD‐1 without the near‐zero optimum average damping ratio, when installing the MTMD for the suppression of undesirable oscillations of structures under earthquakes. Copyright © 2003 John Wiley & Sons, Ltd.     

应变软化在甘肃红柳河辉长质糜棱岩形成中的作用

本文论述的辉长质糜棱岩发现于甘肃北山红柳河蛇绿岩套中。在简单说明了糜棱岩的地质背景及特征、描述了变形岩石的显微构造特征之后，重点对糜棱岩形成过程中的应变软化机制作了论述。探讨了软化岩的存在、组构调整、粒度缩小，长石的动态重结晶，水以及主导变形机制的不断调整与转化等应变软化机制，在应力作用下使岩石逐步软化过程中所起的作用，得出这种糜棱岩是在拆离剪切作用下，应力在蛇绿岩中的软化岩石辉长岩中集中，从而形     

Biomarkers in the Molar Tooth （MT）-Bearing Limestones in the Jilin-Liaoning Area of China

The origin of Molar Tooth (MT) carbonates has been argued for more than 100 years, which are a kind of Proterozoic carbonates especially composed of microsparite with ptygmatically folded and sheet-like structures. Biomarkers detected in the microcalcsparite from the Wanlong and Xingmincun formations in the Jilin-Liaoning area showed there are abundant normal alkanes, isoprenoids, hopanes, steranes, alkylmethylcyclohexanes, and alkyleyclohexanes, indicating a diversity of biological source: long-chain isoprenoids, the major components of chlorophyll, such as C19, C20, a kind of major biomarkers synthesized early by isoprenoid monomers; hopanes a type of characteristic biomarkers from prokaryote, such as archaebacteria and cyanobacteria; sterane a biomarker for eukaryote; and two kinds of alkanes with C17, C18 as the main peaks representing aquatic bacteria and with C23, C24 as the main peaks representing fungi, respectively. Biomarker analysis showed that MT is the result of bacterial and algal activities, which is a kind of organisms between aerobic and anaerobic bacteria, reproducing well in normal or slightly saline sea water under weak oxidation-reduction conditions, resulting in rapid deposition of calcite as microsparite clue to some mechanisms.     

国内外前寒武纪条带状铁建造研究现状

条带状铁建造(BIFs)主要发育于早前寒武纪时期(3.8~1.8Ga),记录了早期地球演化的重要信息且蕴含丰富的铁矿石资源。本文梳理总结了国内外BIF相关领域的研究认识及存在问题:1统计对比显示,BIF沉积事件与地幔柱、地壳增生等重大地质事件相关;2稀土元素及Nd同位素示踪表明,Fe来源于海水与海底高温热液的混合溶液,其中高温热液与海水比例为1:1000;3 BIFs缺乏负Ce异常且富集重Fe同位素,暗示沉积时古海洋整体处于缺氧环境以避免Fe~(2+)发生氧化;4一些重要科学问题尚未解决,例如Si的主要来源、沉淀机制及条带成因等;5华北克拉通BIFs多形成于约2.54Ga,BIF类型、形成时代与富矿成因等问题有待深入研究。本文认为,加强国内外典型BIFs的对比研究并适当应用现代先进测试技术,有利于探索BIF沉积的精细过程及古老克拉通的早期演化。