SQ13正方格子点渗流的重整化群方法

采用实空间重整化群方法,对二元SQ13正方格子点渗流模型进行了研究,得到了临界值P_c,模型在相变点的临界指数v。最后说明了所结果的合理性。     

石济客专引入济南枢纽方案探析

文章分析了石济客专引入枢纽后,枢纽内客运布局及作业分工的变化,择址新建新济南东站作为枢纽内东部城区的主要客站非常必要,重点论述了新济南东站站址方案的研究,经比较推荐平陵城站址方案。     

二价金属离子与咪唑活性位点相互作用的研究

用量子化学从头算方法在HF和MP2水平上运用6-311G**基组,研究二价金属离子(Mg2 、Ca2 、Zn2 )与咪唑活性位点的相互作用.结果表明:Zn2 对咪唑的几何参数影响最大;三种金属离子配合物的稳定化能依次为:Ca2 -咪唑＞Mg2 -咪唑＞Zn2 -味唑,配合物的稳定性顺序为Zn2 ＞Mg2 ＞Ca2 .     

羊抗人IgG的Fab''''片段在单晶硅片表面的位点导向性固定

提出了一种新的固相材料表面固定生物分子的方法。利用羊抗人ＩｇＧ的Ｆａｂ’片段Ｃ末端的唯一自由巯基和三甲氧基丙基巯基硅烷（ＭＰＴＭＳ）化的单晶硅表面的巯基结合位点导向性固定Ｆａｂ’片段。Ｘ－射线电子能谱（ＡＥＳ）和高分辨率的Ｘ－射线光电子能谱表征结果显示了Ｆａｂ’片段成功地固定在单晶硅片表面。为各种生物传感器的敏感层的制备提供了一种较好的途径。     

Genetic insight of the H5N1 hemagglutinin cleavage site

The cleavability of the hemagglutinin (HA) plays a major role in virulence of avian influenza viruses. Detailed analyses of the cleavage sequences and their evolution would give insights into the high pathogenicity of the H5N1 virus. HA segments were visually identifiable in the cellular automata (CA) image, and a feature gene segment (FGS) was only found in H5N1 rather than any other subtype. This FGS is a 30-bp gene segment mainly consisting of ‘A’ and ‘G’. When translated into amino acids the FGS converted into a sequence of mainly basic amino acids with positive charges. This feature amino acid segment (FAAS) was located in the cleavage site loop of HA which was potentially cleavable by various proteases. The 3D structure of H5N1 HA was reconstructed using homology modelling. It was found that the cleavage site loop was well exposed to potential proteases. The molecular surfaces were reconstructed to study how mutation and deletion of some amino acids in the FAAS affected the charge distribution. It was found that some mutations had severely changed the landscape of the charge dis- tribution. Statistical analyses of FAAS were made with respect to when and where the H5N1 viruses were found. In 2005, there were less un-mutated FAAS than the other years according to temporal evolution, and more mutated FAAS appeared in China than other regions according to geographic dis- tribution. These results are helpful for exploring the evolution of virus high pathogenicity.     

龙凤水库坝址比选分析

根据龙凤水库的实地情况,对坝址选择应考虑的各方面因素进行了全面的分析,从而确定了具体坝址.     

深层低渗透砂砾岩油藏注CO2吞吐提高采收率实验研究

深层低渗透砂砾岩油藏地层天然能量较低，压裂后产能递减较快，并且由于地层水敏性以及非均质性较强，采取注水开发的效果较差，采出程度较低。为进一步提高此类油藏的开发效率，开展了注CO₂吞吐提高采收率实验研究，分析了生产压力、焖井时间、吞吐周期以及岩心渗透率对吞吐采收率的影响，并结合核磁共振分析实验研究了CO₂吞吐微观孔隙动用特征。结果表明：生产压力越低、焖井时间越长，吞吐采收率越高；随着吞吐周期的增加，周期吞吐采收率和换油率均逐渐降低；岩心的渗透率越大，不同周期的吞吐采收率就越高；注CO₂吞吐的最佳生产压力为26 MPa,最佳焖井时间为8 h,最佳吞吐周期为5次。岩心的孔隙结构对CO₂吞吐过程中原油的微观动用特征影响较为明显，大孔隙发育较少、物性较差的岩心，吞吐初期主要动用大孔隙中的原油，而吞吐后期采收率的贡献主要来自小孔隙，此类岩心整体采出程度较低；而对于大孔隙发育较多、物性较好的岩心，大孔隙中原油的动用程度一直高于小孔隙，并且总体采出程度较高。S-1Y井实施注CO₂吞吐措施后，日...     

Recognition of Structure Similarities in Proteins

Protein fold structure is more conserved than its amino acid sequence and closely associated with biological function, so calculating the similarity of protein structures is a fundamental problem in structural biology and plays a key role in protein fold classification, fold function inference, and protein structure prediction. Large progress has been made in recent years in this field and many methods for considering structural similarity have been proposed, including methods for protein structure comparison, retrieval of protein structures from databases, and ligand binding site comparison. Most of those methods can be available on the World Wide Web, but evaluation of all the methods is still a hard problem. This paper summarizes some popular methods and latest methods for structure similarities, including structure alignment, protein structure retrieval, and ligand binding site alignment.     

铁路普通无缝线路的技术改造

详细阐述了铁路普通无缝线路技术改造的准备工作、施工程序、注意事项与整理工作,并简要介绍了钢轨现场焊接接头技术。     

钢管混凝土双梁节点试验及现场测试

通过钢管混凝土双梁节点的坚向静力加载试验研究，揭示了该节点的受力机理和破坏形态，并通过实际工程的现场试验研究，验证了模型试验的可靠性。证明了双梁节点具有构造简单、受力明确、施工方便、安全可靠的良好性能。