短线匹配法预制箱梁线形控制方法

短线匹配法预制箱梁施工工艺正逐渐应用于我国大跨度预应力桥梁建设中,预制阶段的线形控制技术是其中的关键.在阐述短线匹配法预制箱梁施工流程的基础上,针对其施工控制特点,着重研究施工控制网的建立、线形测控点的布设、预制坐标系的建立、预制精度的分析、工程独立坐标与桥梁整体坐标的转换、预制过程中的误差分析与修正等线形控制方法.短线匹配法在南京长江第四大桥中的应用,体现了其在特大桥箱梁预制中的优越性和实用价值.     

Distribution of quasars on the sky

It is shown that high-redshift quasars of bright apparent magnitude are concentrated in the direction of the centre of the Local Group of galaxies. A number of them are distributed along a line originating from the Local Group companion galaxy, M 33. A similar, but shorter and fainter line of quasars is seen emanating from the spiral galaxy NGC 300 in the next nearest, Sculptor Group of galaxies. The concentration of bright quasars in the Local Group direction is supported by bright radio sources catalogued in high-frequency surveys. One of the consequences of this large-scale inhomogeneity is to explain the different gradient of radio source counts in the direction of the Local Supercluster, a result discovered in 1978 but never investigated further. Previously reported homogeneity and isotropy of radio-source counts over the sky would seem to be an effect of integrating nearby, large-scale groupings with more distant, smaller-scale groupings over different directions in the sky. More careful analyses as a function of flux strength and spectral index on various scales over the sky are now required. Previous conclusions about radio source and quasar luminosity and number evolution drawn from logN- logS counts would then need to be re-evaluated.     

大失准角的SINS/GPS组合对准算法研究

利用四元数误差方程和非线性滤波技术能较好地解决大失准角下SINS的空中对准问题。迭代滤波比扩展卡尔曼滤波能在更大程度上改善对准精度，但计算量大。针对此不足，本文基于扩展卡尔曼滤波的状态与偏差解耦算法具有较高数值效率和迭代滤波具有较高精度的特点，推导出了一种非线性滤波算法，并对基于加性四元数误差方程的SINS／GPS组合对准进行了数字仿真。仿真结果表明：该算法既具有迭代滤波的精度又比迭代滤波计算量小。     

海底路由勘察自动化成图技术研究

海底路由勘察综合图是海底电缆管道路由区的海底地形地貌、海底面状况和工程地质条件勘察成果的综合反映,是路由设计施工的重要依据。目前综合图的绘制需要大量人工编辑,缺乏批量生产能力,本文研究了路由勘察数据特征,利用AutoCAD VBA开发技术实现了水深数据分级分色展绘、地形剖面成图、浅地层剖面解译数据剖面投影以及成果图框的自动化生成,应用证明该技术对降低作业难度、提高内业处理效率具有较高的实用价值。     

Polarization of climate politics results from partisan sorting: Evidence from Finnish Twittersphere

Prior research shows that public opinion on climate politics sorts along partisan lines. However, they leave open the question of whether climate politics and other politically salient issues exhibit tendencies for issue alignment, which the political polarization literature identifies as among the most deleterious aspects of polarization. Using a network approach and social media data from the Twitter platform, we study polarization of public opinion toward climate politics and ten other politically salient topics during the 2019 Finnish elections as the emergence of opposing groups in a public forum. We find that while climate politics is not particularly polarized compared to the other topics, it is subject to partisan sorting and issue alignment within the universalist-communitarian dimension of European politics that arose following the growth of right-wing populism. Notably, climate politics is consistently aligned with the immigration issue, and temporal trends indicate that this phenomenon will likely persist.     

输水渠道线路优化与漫游数学家模型

在传统漫游数学家模型的基础上,以线路定性方案、渠段纵坡为决策变量,工程总投资为目标函数,考虑渠段线路状态转移和渠道首末水位约束,提出了阶段函数已知情况下的长距离输水渠道线路优化二维动态规划模型。实例证明该法对长距离输水渠道线路系统的优化比传统线路方法更优越。     

对称基本型回旋曲线平移算法初探

在市政工程(电信、电力、上下水、热力等线性工程)、道路公路设计和测量定线中经常遇到这样一类问题,即当带有回旋曲线的道路中线一经确定,其路边线、辅路、匝道和其他市政配套管线要求与主路中线平行布设,这样就提出了回旋曲线如何平移最为合理的问题。此文就以对称基本型回旋曲线为例,对这一课题的几种计算方法进行初步的探讨,以供参考。     

基于惯性导航系统的轨道检查仪双位置对准方法

为提高轨道检查仪惯性导航系统对准精度,提出适用于轨道检查仪的惯性导航系统双位置对准方法。该方法利用轨道检查仪掉头方式,实现惯导系统加速度计常值零偏补偿。选用0.1°/h光纤陀螺仪和200 μg石英挠性加速度计组成惯性导航系统,在一铁路路段进行轨道检测试验。试验结果表明,双位置对准方法能够有效去除惯性器件零偏误差导致的轨道参数检测误差,在轨检仪连续工作300 m的情况下,铁路轨道水平检测精度明显提高。     

中国-朝鲜长白山区新生代火山事件的划分及对比

中朝长白山地区新生代火山堪称东北亚之冠 ,为进一步认识火山时、空、物的演化发展势态 ,对活动的稳定性作出科学评估 ,综合分析了 6 0年代以来 ,特别是近期中、朝地质学家的成果 ,从火山事件地层学理论出发 ,对该区提出划分 31次火山事件的新方案     

RTK技术在线路控制测量与恢复定线中的应用

主要介绍了RTK技术在线路控制测量与恢复定线中的应用,对控制测量精度进行了一定的分析,综合考虑线路控制测量在RTK作业时应求得转换参数以进行两种坐标系的实时转换,在两个控制点间的线路应选用该两点的两套坐标求转换参数,得到两个坐标系的尺度参数姿,恢复定线时考虑高斯平面上的坐标点再投影到建筑面上来,这是一个相反的过程。改正系数1/K对放样元素的影响得出一些有益的结论和体会。