选育品种松荷鲤遗传结构研究

本研究随机选取了136尾松荷鲤个体,利用30对多态性较高的微卫星标记对该品种的遗传结构进行了分析。结果表明:群体平均等位基因数(A)为8.33,有效等位基因数(Ae)为5.91,期望杂合度(He)值为0.81,平均多态信息含量(PIC)为0.78,显示出群体丰富的遗传多样性;哈迪-温伯格平衡检验结果显示超过半数的位点都发生了显著或者极显著偏离平衡,表明人工选择压力对群体结构造成了很大的影响;种群有效群体大小和群体瓶颈效应分析表明,有效种群大小约为133,种群近期内可能经历了遗传瓶颈。本研究通过对选育品种松荷鲤遗传变异进行了分析,初步了解了该品种的遗传结构,为松荷鲤的种质资源保存和利用提供了支持。     

Excel在水准测量内业处理中的应用

本文就Excel在二等水准测量内业处理中的应用加以比较详细的论述和探讨,使本来需要几个计算过程的平差变成了一个过程.充分发挥计算机的高效作用,大大提高了内业处理的效率.     

Explosive compaction technology for loess embankment settlement control: numerical simulation and field implementation

Loess covers about one-tenth of the world’s land area. While it is often used as embankment fill, loess is not an ideal construction material due to its wet collapsible nature, as it may cause significant embankment settlement and other related problems. Although explosive compaction (EC) technology has been used for many years, the challenges in experimental testing and theoretical analysis hinder its wider application. This paper contributes to the development of a design construction scheme of EC technology for loess embankment improvement through an integrated approach that involves finite element modeling, small-scale experiments, full-scale simulation and field implementation. In this study, a reliable finite element model is developed and validated through a small-scale experiment. The model is developed based on the software ANSYS/LS-DYNA^®14.5 and takes into account the coupling between different materials (including soil, explosives, air and pavement). Critical performance factors such as the volume of the explosion cavity, the density of the compacted soil and the soil pressure can be obtained directly from the model. The model is then extended to simulate full-scale embankments. A sensitivity study is conducted to establish the correlations between the design parameters and the abovementioned performance factors. The relationships served as design guidelines for the successful implementation of the EC technique in an embankment section on the Cheng-Chao highway in China. The results demonstrated the feasibility of the EC technique as a ground improvement method for loess embankments, and it illustrated the effectiveness of the numerical method as a tool in design.

     

利用特征选择自适应决策树的层次SAR图像分类

提出了一种新的基于特征选择自适应决策树的层次分类算法,用于合成孔径雷达（synthetic apertureradar,SAR）图像的分类。采用Joint Boosting算法选择出最适用于各类的特征组合,并自适应地搜索构造出一个由两类分类器构成的层次分类器,利用特征选择结果和自适应决策树进行了SAR图像的学习和推理,实现了自动分类,在国内首批极化干涉SAR数据上的实验证明了本算法的有效性。     

单点数字检波器地震资料中弱信号特征分析及识别方法

弱信号的检测和识别是当今地球物理学界非常关注的一个技术问题.对于高密度单点资料究竟多弱的信号才是弱信号,如何检测和识别,以往学术界很少有这样的文献报道.本文以理论研究为主,结合胜利油田某高密度实际资料,对此做了分析和讨论,得出以下初步结论:①就视觉分辨率而言,当弱信号的信噪比S/N＞2时,较易识别;S/N=1时,有可能...     

海洋能产业项目技术经济可行性评价研究

作为新兴的能源产业,海洋能产业项目在快速发展过程中必将带来一系列新的问题,这些问题对项目的投入与产出评价分析有着复杂而深远的影响。为了提高海洋能产业项目投资的准确性和合理性,有效降低投资风险,文章阐述了可行性研究的概念,介绍了海洋能产业项目技术经济可行性研究内容,为海洋能产业项目可行性分析提供理论和方法参考。     

敦煌莫高窟窟顶沙丘移动的初步研究

通过窟顶风沙资料的理论计算和沙丘动态监测，首次提出了窟顶沙丘移动方向为ＳＷ→ＮＥ向，移动方式为盘旋式－慢速稳定型。窟顶沙丘年平均移动量０．４２ｍ／ａ，入窟沙量４２９１ｍ￣３。在近百年内，沙丘不会埋没洞窟，但风沙流的危害仍十分严重。因此防止窟顶风沙流的危害是目前石窟保护中急待解决的重要问题。