Sequencing analysis of a 40·2 kb fragment of yeast chromosome X reveals 19 open reading frames including URA2 (5′ end), TRK1, PBS2, SPT10, GCD14, RPE1, PHO86, NCA3, ASF1, CCT7, GZF3, two tRNA genes,three remnant delta elements and a Ty4 transposon

The complete sequence of a 40 247 bp DNA segment located on the left arm of chromosome X of Saccharomyces cerevisiae has been determined and analysed. The sequence encodes the 5′ coding region of the URA2 gene and 18 open reading frames of at least 100 amino acids. Ten of these correspond to known genes, whereas eight correspond to new genes. In addition, the sequence contains a tRNA-Ala gene, a tRNA-Asp gene, a Ty4 transposable element and three delta elements. The sequence has been deposited in the EMBL databank under Accession Numbers: Z49405, Z49404, Z49403, Z49402, Z49401, Z49400, Z49399, Z49398, Z49397, Z49396, Z49394, Z49392, Z49391, Z49390, Z49389, Z49387, Z49386, Z49385.     

我国宜一步到位发展高速磁悬浮列车——先行建设宁沪杭甬高速磁悬浮列车线

高速磁悬浮列车是 2 1世纪新型的、理想的交通工具 ,具有较多的优越性 ,其技术已趋成熟。我国应跨越轮轨铁路 ,一步到位发展磁悬浮列车。长江三角洲地区经济、社会飞速发展 ,区域需要建立快速、安全、舒适、清洁、节能的高速主通道。先在沪宁线或沪杭甬线上建试验段 ,然后建设宁—沪—杭—甬高速磁悬浮列车线 ,成为区域内实现 2小时经济圈的主通道     

探索城市景观桥梁的建筑造型

本文通过对单体景观桥梁和群组景观桥梁的典型工程的分析,阐述了建筑师对于城市景观桥梁的造型的理解和探索,通过案例总结出不同种类景观桥梁造型的塑造方法并以建筑师的表达方式来满足社会对景观桥梁的需求。     

Warning Odor of the North American Porcupine(Erethizon dorsatum)

Volatile compounds in the lipid coating of the lower-back quills of the North American porcupine,Erethizon dorsatum, were collected using headspace trapping on Tenax and analyzed by gas chromatography–mass spectrometry (GC-MS), GC with organoleptic detection, and GC with a chiral stationary phase. Over 50 components were isolated, primarily oxygenated aliphatics, lactones, and isoprenoids. The most abundant constituent was tetradecyl acetate, which does not contribute significantly to the odor of the quill lipids. GC with a wide-bore capillary column and a human nose as detector was used to determine the retention time of the peak with the characteristic porcupine odor. Comparison of this organoleptic chromatogram with those obtained with a flame ionization detector and GC-MS showed the compound to be a -decalactone. The racemic mixture of this optically active substance does not possess the unique odor. Resolution of the enantiomers of -decalactone by GC with a chiral cyclodextrin phase shows that the isomer possessing the characteristic porcupine odor is the(R)--decalactone. We suggest the biological function of this compound is to serve as a warning odor, which, in conjunction with an initial quill strike, produces a conditioned aversion in potential predators.     

大港孔店南部王官屯地区孔三段扇三角洲沉积特征及典型相序

在黄骅坳陷孔店南部王官屯地区孔三段扇三角洲沉积体系岩性相、测井相、地震相分析研究基础上,对该区扇三角洲沉积体系进行了沉积微相组合划分,并对各沉积相组合特征分析。研究认为,该区扇三角洲沉积的总体特征为：近源、粒级粗、堆积速率快,岩石相、地震相类型丰富。同时还建立了该区扇三角洲相的典型相序。研究结果对该区隐蔽油气藏的勘探具有一定的指导意义。     

纳雍地区龙潭组中段沉积序列模式及沉积体系的初步研究

本文在对贵州省纳雍地区龙潭组中段一剖面详细研究的基础上,划分出八种主要岩相类型,在此基础上,运用马尔可夫链分析法建立了该段的两种主要序列模式,通过沉积序列分析认为:该区龙潭组中段为一受潮汐影响的三角洲体系。     

论长江口的综合整治与开发

科学把握长江口的演变趋势,是制定长江口综合整治与开发方案的基础;维护健康长江、促进人水和谐,是保障长江口地区社会经济可持续发展的关键;满足航运发展需要,是长江口综合整治与开发的首要任务;人工河口是长江口综合整治与开发的长远方向;整治、围垦、疏浚相结合是长江口综合整治与开发的主要措施;控制和稳定河势是当前长江口综合整治与开发中急迫需要解决的问题;加强长江口的统一管理是促进长江口科学整治和合理开发的有力保障.     

浦东机场跑道工程江砂开采及对河道的影响

为满足浦东国际机场工程建设需要,从有利于河势和航运等角度出发,选择了长江口南槽江亚南沙南侧、九段沙保护区外侧的砂源区作为工程采砂区,并拟定采砂方案。采用delft 3D模型分析采砂前后工程区附近的流场变化。并从河势、防洪、水环境、通航、航道和生态等方面分析了采砂对长江口南槽河段的综合影响,论证采砂的可行性。通过分析得出采砂对长江口河道基本无影响。     

ADCP在长江内河流量比测试验与精度研究

根据长江中下游主要控制河段采用ADCP测流方式，结合长江河流水沙特性、测站特征和水文测船等具体情况，通过野外比测试验，针对ADCP存在的“适宜性”和流量测验精度等问题，进行了较为全面、深入、细致的分析研究．提出了一套能使ADCP适应于长江内河河流特性、现有测船条件的流量测验方法、精度指标等成果，具有广泛的推广应用价值。     

水泥土搅拌桩在长江干堤防渗工程中的应用

水泥土搅拌桩建造防渗墙作为堤防防渗加固处理的一种重要施工方法 ,在长江干堤整险加固工程建设中得到了大量应用。笔者对其在工程中的应用情况、施工控制参数、质量检测方法及存在的问题进行了介绍 ,并提出了搅拌桩的成墙特点及存在问题