Papers by Keyword: Alignment

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Authors: Fei Li, Lin Li, Bao Yu Hong, Wen Li Liu
Abstract: A collimator is one of the most popular optical instruments used in optical workshop and parallelism of the beams is the key technical indicator of collimator. A great deal of efforts has been expended to ensure reticle locate at the focal plane. In this paper, a new laser differential confocal collimator alignment method is proposed for precision alignment of collimators. Based on this principle an experimental setup is built up and used to align two collimators whose focal lengths are 600mm and 1000mm and f-numbers are both 10.The wave-front parallelism error of the laser differential confocal system and the tested collimator is measured by the verified experiment based on scanning penta prism method. At last some influence factors alignment precision is analyzed. Theoretical analysis and experimental results show that the alighment precision based on laser differential confocal method can reach to 0.004mm.and can be a high-efficiency approach to align collimators, especially in industry production.
Authors: Ting Zhong Xu, Hebibul Rahman, Li Bo Zhao, Yu Long Zhao, Zhuang De Jiang
Abstract: The rheology of nanowires (NWs) and nanotubes (NTs) in shear flow has been analyzed by molecular dynamics (MD) simulation and macrofludic simulation. A method based on macrofludic system for aligning NWs and NTs is demonstrated. In this method, vortex is generated near the surface of a plane by using a mushroom like turnplate. Then a uniform velocity gradient was generated on the surface of the plane. Through controlling the rotational speed of the turnplate, the rheology of NWs and NTs in suspension can be easily controlled. So it provides a more effective and economical method for the alignment of NWs and NTs, as well as forming the anisotropy NWs and NTs bulk material.
Authors: Yun Wei You
Abstract: By applying the model in a case, two methods of linear and curved alignment are analyzed and compared. Besides, the main existing problems and the solutions to solve them are studied. The results show that curved alignment method has obvious advantages in highway design, interchange design, and other complex terrain conditions. With a variety of computer-aided design software line appears, curved alignment method will be widely used.
Authors: Sheng Bao, Fu Zhang, Xi Zhang
Abstract: The random errors exist in measuring with touch trigger probe. These errors are directly introduced into workpiece coordinate system with conventional alignment method. An enhanced measuring method is proposed in this paper to improve the accuracy of alignment for five-axis CNC machine tools. By using the method of least square, an error reference frame is constructed, and the relationship between the alignment parameters and the error reference frame is derived. An example of aircraft structural parts is presented to validate the presented method.
Authors: Ming Wen Wang, Niann I Yu, Wen Hao Liao
Abstract: Studies have proved that enhancing epoxy matrices by adding carbon nanotubes to form structural reinforcements has significantly improved mechanical properties at very low carbon nanotube loading. That mechanical properties of aligned composites are better than those of random ones has been demonstrated in past studies; however, alignment is not easy to achieve in carbon nanotube epoxy-matrix bulk composite by conventional techniques. In this study, epoxy-matrix bulk composites reinforced by aligned multi-walled carbon nanotubes (MWCNTs) are prepared using an RF electric field to elicit dipolar interactions among the nanotubes in a viscous matrix following immobilization by curing under continuous application of an anisotropic electric field and the fracture toughness is experimentally characterized later. The processes of actively aligned MWCNTs epoxy-matrix bulk composite were controlled as a function of CNT weight fraction, the frequency of dielectrophoretic field and processing time. Carbon nanotubes are not only aligned along the field but also migrate laterally to enhance thickness. Eventually, addition of nanotubes improved the mechanical properties of the MWCNT/epoxy bulk composites, and the increase in the flexural modulus and fracture toughness with the aligned nanotube composite is two times greater than the improvement for the randomly oriented composite.
Authors: Fang Liu, Wei Wang, Kui Li, Lei Wang
Abstract: Aircrafts with common attitude maneuverability (e.g. helicopter) are in more and more urgent need of low cost and high precision inertial navigation system (INS). To meet this demand, a scheme of fiber-optic gyroscope (FOG) strapdown inertial navigation system (SINS) with single-axis to and fro rotation-modulation method is adopted. A short-time alignment method bases on open-loop mathematic platform misalignment model is studied. The test results from the actual system show that this method has characteristic of high accuracy and simple, reliable operation. The estimate accuracy of azimuth error and is less than 2’. And the estimate error of north drift achieves 0.001º/h. Simultaneously, the input-axis accelerometer bias and gyroscope drift are estimated exactly.
Authors: Arnold C. Vermeulen
Abstract: The alignment of a ¼-circle Eulerian cradle is discussed. The method is based on diffraction and uses a special alignment tool and a stress-free powder sample. A new profile shape function is introduced to describe better distorted diffraction peaks.
Authors: Vladimir S. Obraztsov, Alexander A. Ageichik
Abstract: The results of new alignment technique for a telescope with the Epps-Shulte focus are presented. The technique is based on application of the synthesized holographic elements and IR interferometry.
Authors: Xiu Zhen Lu, Bo Peng, Yan Yan Chang, Ming Tao Xu
Abstract: Aligned array electrospun nanofibers are preferred and even necessary in most of applications. Most research reported was focus on the quality and uniform of directions of the array nanofibers. This paper describes a simple method for fabrication of large area aligned naonofibers. A zigzag shape collector was used in the electrospinning system. Alignment of nanofibers was realized by this system. Nanofibers collected on the peak and valley of the Aluminum foil were oriented. This system is a hybrid structure of parallel electrodes and disc collector with tip-like top.
Authors: Z.C. Yuan, S. Blackburn, A.J. Williams, I.R. Harris
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