Unexpected diversity of small eukaryotes in deep-sea Antarctic plankton

Phylogenetic information from ribosomal RNA genes directly amplified from the environment changed our view of the biosphere, revealing an extraordinary diversity of previously undetected prokaryotic lineages. Using ribosomal RNA genes from marine picoplankton, several new groups of bacteria and archaea have been identified, some of which are abundant. Little is known, however, about the diversity of the smallest planktonic eukaryotes, and available information in general concerns the phytoplankton of the euphotic region. Here we recover eukaryotes in the size fraction 0.2-5 microm from the aphotic zone (250-3,000 m deep) in the Antarctic polar front. The most diverse and relatively abundant were two new groups of alveolate sequences, related to dinoflagellates that are found at all studied depths. These may be important components of the microbial community in the deep ocean. Their phylogenetic position suggests a radiation early in the evolution of alveolates.     

Mesoscale vertical motion and the size structure of phytoplankton in the ocean

Phytoplankton size structure is acknowledged as a fundamental property determining energy flow through 'microbial' or 'herbivore' pathways. The balance between these two pathways determines the ability of the ecosystem to recycle carbon within the upper layer or to export it to the ocean interior. Small cells are usually characteristic of oligotrophic, stratified ocean waters, in which regenerated ammonium is the only available form of inorganic nitrogen and recycling dominates. Large cells seem to characterize phytoplankton in which inputs of nitrate enter the euphotic layer and exported production is higher. But the size structure of phytoplankton may depend more directly on hydrodynamical forces than on the source of available nitrogen. Here we present an empirical model that relates the magnitude of mesoscale vertical motion to the slope of the size-abundance spectrum of phytoplankton in a frontal ecosystem. Our model indicates that the relative proportion of large cells increases with the magnitude of the upward velocity. This suggests that mesoscale vertical motion-a ubiquitous feature of eddies and unstable fronts-controls directly the size structure of phytoplankton in the ocean.     

馏分油脱酸剂技术的应用研究

针对直馏柴油、减压馏分油碱洗电精制脱酸工艺存在的不足,开发了一种新的馏分油脱酸剂技术,完成了实验室研究、工业试验和工业应用。该技术使用现有的馏分油碱洗电精制工艺设备,只需增加水洗和脱酸剂回收系统,技术改造费用少。与传统的碱洗脱酸工艺比较,具有适应原料范围宽,烧碱用量下降67% ~75%,完全消除乳化,混合强度不影响脱酸效果,馏分油损失下降50% ~60%;脱酸剂再生循环使用,无废碱液排放,环境污染大为降低等优点。在最优操作条件下精制油酸值为零,已达到最苛刻的变压器油酸值指标(酸值<0. 017mgKOH/g),回收石油酸达到石油酸一级品65号酸的质量标准(SH/T0530-92)。     

GA-ANN综合优化地震属性的应用研究

讨论了应用遗传算法对地震属性进行优化组合的合理性和可行性,并依据遗传算法的框架提出了算法的实现步骤。在设计个体适应度评价函数环节讨论了以对非线性映射具广泛适应性的人工神经网络模型替代优化目标函数的思想的合理性及实现方法。最后以应用实例的数据对算法进行了检验并得到较满意的结果。     

界面特性对聚合物驱油时驱替速度的影响分析

针对界面特性（界面流变特性、界面张力特性、润湿性）在聚合物驱油过程中的重要性,将油藏孔隙介质简化成具有相继收缩和扩张的波纹管模型,根据能量平衡原理建立了波纹管中聚合物溶液驱替时的界面特性参数和驱替速度之间的数学模型,用有限差分方法求解,研究了界面粘度、界面张力、润湿角变化对聚合物/油界面速度的影响。研究结果表明：润湿性变化影响界面的驱替速度,当界面的曲率方向与驱替方向相反时,无因次界面张力和无因次界面粘度的增加都使无因次界面轴向速度降低,且界面轴向驱替速度关于孔隙单元中心不对称。     

应用油藏规模序列法预测东营凹陷剩余资源量

随着油气勘探程度的不断提高,未发现的剩余油气资源越来越少。如何准确预测高勘探程度即成熟探区的剩余油气资源,成为石油投资者和油气资源评价工作者关注的焦点。详细探讨了油藏规模序列法预测油气资源的原理、方法、操作流程及存在的问题,并运用该方法对东营凹陷剩余可探明储量以油气成藏体系为评价单元进行了预测。研究表明,东营凹陷剩余可探明储量约为17.03×10⁸t,仍具有较高的勘探潜力,并且主要集中在东营中央背斜带和东营凹陷北坡两个油气成藏体系内。实践证明,由于油藏规模序列法合理回避了油气成因机理问题,减少了资源评价工作中人为因素的影响,使资源评价结果更为客观。     

水平井产能预测相关式研究

针对水平井的稳态产能预测误差较大的问题,通过半解析耦合模型计算对比,发现在不同泄油体形态、水平垂直渗透率各向异性条件下,Joshi公式的误差变化规律：在厚油层、低垂向渗透     

考虑热损失非牛顿稠油热采不稳定试井分析

针对蒸汽未波及区的油层没有得到有效改善这一问题,通过采用内区考虑热损失,外区考虑为非牛顿幂律流体复合模型分析,求得了无限地层情况下的拉氏空间解。通过数值反演方法作出了相应的样版曲线,并且对样版曲线作了相应的敏感性分析。新的样版曲线在非牛顿流的影响下有别于常规复合油藏,外区径向流段不再呈现一般的水平直线段,在交界处由于冷凝系数的影响,压力导数出现明显的下掉现象,冷凝系数越大,下掉越严重。为稠油开发油藏压力动态分析提供了一种新的模型。     

Simulation for the primary electronic donor of photosystem IIin vitro

Histidine coordinated to Chi a is a distinct characteristic of Chl ain vivo. By using histidine analogue of 1-methylimidazole (C₄H₆N₂2) and measuring the UV/vis absorption, CD and MCD spectra of the interaction between C₄H₆N₂ and Chl a in CCI₄, we have obtained that: (i) In pure CCl₄ solvent, Chl a molecule is in five-coordinate state, and two Chl a molecules form an asymmetric compact-dimer with strong coupling interaction. We propose that the two Chl a molecules are connected by two unequally coordinated Mg-O bonds (the two oxygen atoms come from the C=O of C13¹ keto and C17 ester, respectively); (ii) when the molar ratio of C₄H₆N₂/Chl a is 0.5 or 1 (corresponding to 2Chl a · 1C₄H₆N₂ and 2Chl a · 2C₄H₆N₂, respectively), significant changes have been observed in the absorption, CD and MCD spectra, which indicate that the Chl a remains in dimer form, but the coupling interaction between them reduces greatly. We postulate that C₄H₆N₂ replaces the ligation of C=O of C17 ester and C13¹ keto to Mg atoms sequentially. The two Chl a molecules linked by two weakly interacted Mg…O bonds form a relaxed-dimer. The structure of the model is essentially similar to that of the primary electronic donor, P₆₈₀, of photosystem II in high plants and algae.     

有利砂体识别与解释

天然气的产量与砂岩的厚度,孔隙度,连通性,砂泥比等有密切的关系。为了解决砂体在空间以什么形态出现,其方向如何,纵向上如何变化,连通形式如何等问题,在前人研究的基础上,对篷来镇组某工区的砂体进行了精细识别和解释。在地震剖面上,砂体的响应一般表现为强振幅,低频率。孔隙性好,含气丰度高的砂体往往表现为速度低和极性反转的特点。但发现该工区的砂体在地震剖面上表现形式多变,甚至出现了合成地震记录与井旁地震记录严重不吻合的现象,故砂体识别工作不能遵循统一模式。因此,采用了多井约束,多层标定,分层解释来识别有利砂体。