共查询到20条相似文献,搜索用时 140 毫秒
1.
2.
垂准仪实际上是对大地重力铅垂线(自然基准)进行复现的仪器.而所复现的重力铅垂线的准确程度(或不确定度)是我们所关心的.所以垂准仪的校准,实际是要检查仪器给出的重力铅垂线的计量性能。为达到此目的,应该建立更高等级的重力铅垂线计量标准.这里暂称为“垂准标准”.并应使仪器给出的重力铅垂直线与标准重力铅垂直线——垂准标准进行比较.以实现对垂准仪的校准。这就是说,对垂准仪进行校准时. 相似文献
3.
研究并建立了定标用多通道紫外日光模拟仪及量值溯源装置。模拟仪的输出光谱分布满足欧洲化妆品盥洗用品及香水协会等组织的技术指标要求。研制了光辐射度定标和测量转接器,有效解决了模拟仪输出光斑小、辐照分布不均匀、光导弯曲易改变光谱分布等测量问题,实现了模拟仪光谱辐射照度和光谱匹配的高准确度测量,以及UVA和UVA+B积分辐射照度量值的准确溯源。并研制了SPF紫外辐射照度测量仪表,用于 UVA和UVA+B积分辐射照度量值的测量、保存与传递,其量值溯源至光谱辐射照度国家基准装置。 相似文献
4.
<正>0引言垂准仪是以重力线为基准,给出铅垂直线的光学仪器,广泛应用于建筑施工和设备安装中提供铅垂线。垂准仪分为光学垂准仪和激光垂准仪两种,目前,激光垂准仪由于直观、容易操作,其使用量高于光学垂准仪。激光垂准仪使用简单,携带方便,可以提供上下双向重力准线,市场保有量和使用量较大。不过,相比于光学垂准仪,激光重力准线难以校准。垂准仪最主要的指标为其重力准线偏差, 相似文献
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
为了更加准确地评定用水平仪测量竖直轴系的倾角回转误差,利用水平仪测试数据中误差的组成成分,明确两维水平仪读数中的谐波成分与回转误差中的谐波成分的相互关系。基于已有的2种数据处理方法,提出了将测量数据转换到固定坐标系下2种新的处理方法。详细分析了4种数据处理方法的优缺点,其中一次谐振分离方法将回转误差中的一次谐振量成功分离,得到了完整的回转误差。通过改变铅垂度,对轴系回转误差进行8次测量,对比所辨识的参数,从而验证了该方法的正确性。 相似文献
16.
M.R. Gecit 《International Journal of Engineering Science》1981,19(6):747-755
This paper is concerned with the axisymmetric problem of an elastic layer lying on a semi-infinite foundation. The layer is pressed against the foundation by a uniform clamping pressure applied over its entire surface and a uniform vertical body force due to the effect of gravity. In addition, an axisymmetric vertical line load is applied to the layer. It is assumed that the contact between the layer and the foundation is frictionless and that only compresive normal tractions can be transmitted through the interface. The contact along the interface will be continuous if the value of the line load is less than a critical value. However, interface separation takes place if it exceeds this critical value. The problem is formulated and solved for the cases of tensile and compressive line loads. Numerical results for contact stress distributions are given for different material combinations. 相似文献
17.
The effect of irregularities of the refractive index of a terrestrial layer of the atmosphere on the slope of the polarization
plane of an electromagnetic wave is evaluated numerically. An optical range polarimeter is developed having a sensitivity
of the order of 1″. The possibility is demonstrated of practical application of the polarization plane as a basis for direct
measurement of the relative angular positions (deviations) of a plumb line at scattered points of the earth’s surface. 相似文献
18.
L. Quettier 《低温学》2010,50(9):534-540
Simulating a reduced gravity environment experienced in spaceships in a laboratory setting for studying different technical aspects (fluid transfer or propellant behavior, for example) is a primordial step prior to extraterrestrial explorations. We first present some results on boiling heat transfer in helium under reduced gravity using a commercial magnet and point out the limitations in volume and magnetic force homogeneity to perform reduced gravity experiments with such a non ad hoc magnet. Then, we present a new magnetic design to create a reduced gravity environment in large volume suitable for boiling test experiments in oxygen. Based on a modified design we present the magnetic configurations that allow compensating gravity for different elements such as hydrogen, water or helium but in smaller volumes. We detail the different aspects of winding techniques to achieve the requirements on magnetic force. 相似文献
19.
20.
将主销后倾角和主销内倾角纳入“四轮定位”概念,相对于非转向轮推进线对这些角度进行了定义,推导出转向系统几何参数之间的关系,进而得出后倾角和内倾角的计算公式(测量原理)。由于在不可见的转向轴线平面投影图上无法安装测量装置,因此可以利用推导出的计算公式间接测量后倾角和内倾角,同时阐明了使用这种测量方法必须遵守的限制条件,并以FNCA型非接触式车轮定位仪为例简单介绍了转向轴线几何参数的测量过程。 相似文献