共查询到20条相似文献,搜索用时 125 毫秒
1.
本文介绍具有缓和曲线圆曲线的2种测设方法:a.分布测设缓和曲线和圆曲线;b.在直缓点或缓直点1次设站连续测设近端缓和曲线和圆曲线。同时给出2种测设方法的切线支距法和偏角法的公式。 相似文献
2.
在公路测设中,用切线支距法与弦支距法结合完成曲线测设,并用PC—1500机辅助计算,能简化计算过程及正确完成曲线测设。 相似文献
3.
在公路测设中,用切线支距法与弦支距法结合完成曲线测设,并用PC-1500机辅助计算,能简化计算过程及正确完成曲线测设。 相似文献
4.
根据多年的公路测设经验,利用虚交基线结合切线支距法和弦支距法测量原理,总结出一种公路平曲线测设的高效方法-虚交基线支距法。章介绍了虚交基线支距法的计算方法与测设方法。尤其在树木茂密的林区与房屋密集的村镇使用虚交基线支距法测设公路平曲线,既可减轻劳动强度,又可节省时间,提高工作效率;而且测设精度高,不存在误差累计。 相似文献
5.
本文通过一系列数学推导,得出了复曲线上待测点及任意测站点的坐标公式,使极坐标法施测复曲线成为可能,为在不利的环境中施测复曲线提供了一个既简便又灵活的新方法。 相似文献
6.
7.
8.
9.
10.
回头曲线是林区公路常用的展线方法,由于大部分都是在山坡上作业,给选线定线带来一定困难。现介绍一种用图解法测设回头曲线的方法,供试用。回头曲线分马蹄形(圆心角<180°)和发针形(圆心角>180°)两种,都可用图解法测设。具体测法如下: 相似文献
11.
测量纤维增强体渗透率的重要性在于:一方面它控制充模时间,从而与树脂的固化动力学一起影响模具设计和注射口、排气口的位置,是数值模拟所需的关键参数;另一方面,它决定流动特性,控制树脂对纤维束的浸渍方式,是获得高品质制品的关键。笔者以平流法为基础,基于流体动力学原理,给出一维单向渗透率和二维径向渗透率的计算方法,并通过实验测量了一维单向渗透率值和二维径向渗透率值。结果表明:测量树脂对亚麻纤维织物的一维单向渗透率值时,渗透率值呈先增大后减小再增大的趋势,测量树脂对亚麻纤维织物的二维径向渗透率值时,两个坐标轴的轴向渗透率值大小不等,树脂在亚麻纤维织物内的流动是一个从非稳态到稳态的过程。 相似文献
12.
采用“坐标法”定线和放样与传统方法相比较,具有灵活、方便、准确的特点。能节省很多工作量和时间。本文介绍的方法在设计测量中有较高的使用价值。 相似文献
13.
Mitsuru Taniwaki Hidemi Akimoto Takanori Hanada Minami Tohro Naoki Sakurai 《Wood material science & engineering》2007,2(2):77-82
A method of measuring moisture content of wood is introduced. This method uses a vibrational technique. A shaker driven by swept sine signals was used for the accurate generation of vibration. A cylindrical wood sample was used to verify the method of measuring the moisture content. Resonance frequencies of the wood sample decreased as its moisture content increased. An experiment was performed by measuring the vibration of a tree to explore the feasibility of applying the method to the measurement of the moisture content of trees. The circumferential mode, which is independent of the height of a tree, was identified using a white oak tree. 相似文献
14.
15.
《Wood material science & engineering》2013,8(2):77-82
Abstract A method of measuring moisture content of wood is introduced. This method uses a vibrational technique. A shaker driven by swept sine signals was used for the accurate generation of vibration. A cylindrical wood sample was used to verify the method of measuring the moisture content. Resonance frequencies of the wood sample decreased as its moisture content increased. An experiment was performed by measuring the vibration of a tree to explore the feasibility of applying the method to the measurement of the moisture content of trees. The circumferential mode, which is independent of the height of a tree, was identified using a white oak tree. 相似文献
16.
17.
I. L. Post J. C. Atherton C. P. Vendhan Professor R. R. Archer 《Wood Science and Technology》1980,14(4):289-296
Summary Previous methods for measuring residual longitudinal growth strain distributions in logs are reviewed. An extension is given of Jacobs' method for measuring growth strains which yields residual strain information at many points in the cross section other than along the diametrical plank. Some of the longitudinal growth strain distributions measured using the new method are presented.This work was supported in part by NSF Grant ENG-74-02428 相似文献
18.
Summary A new method is presented for measuring fractional cell wall area by use of photomicrographs of cross sections of wood. The method is geometric in approach and measures, within a delineated area of complete cells, compound cell wall thickness of adjoining cells in systematically or randomly selected locations. In comparison to point sampling (dot grid method), applied with single or repeated trials, the proposed method is shown to require a lesser number of samples for the same statistical accuracy. In addition to fractional cell wall area, the method serves to determine mean cell and lumen area (or diameter). 相似文献
19.
对汽车在道路条件下进行燃料消耗量试验时.影响燃料消耗量测量的主要因素及误差做了全面的分析。并提出了控制误差的主要措施。 相似文献