scholarly journals A Novel Multi-Angle SAR Imaging System and Method Based on an Ultrahigh Speed Platform

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1701 ◽  
Author(s):  
Wensheng Chang ◽  
Haihong Tao ◽  
Guangcai Sun ◽  
Yuqi Wang ◽  
Zheng Bao

Considering the difficulty of pulse repetition frequency (PRF) design in multi-angle SAR when using ultra-high speed platforms, a multi-angle SAR imaging system in a unified coordinate system is proposed. The digital multi-beamforming is used in the system and multi-angle SAR data can be obtained in one flight. Therefore, the system improves the efficiency of data recording. An improved range migration algorithm (RMA) is used for data processing, and imaging is made in a unified imaging coordinate system. The resolution of different view images is the same, and there is a fixed delay between the images. On this basis, the SAR image fusion is performed after image matching. The results of simulation and measured data confirm the effectiveness of the system and the method.

Author(s):  
G. J. Parker ◽  
E. Bruen

This paper describes an investigation into the behaviour of drops which impinge upon dry and wet surfaces. This is of particular interest in the context of the wet steam turbine. Two approaches have been made in the studies; these are: (1) Drops were made to impinge normally on to various types of dry, stationary surfaces. The drops were in the size range 300–1500 μm diameter with velocities of 2–9 m/s. (2) Drops were made to impinge on to surfaces moving with considerable velocity at right angles to the motion of the drop. Surface velocities ranged up to 45 m/s. The latter study is of direct interest for the splashing of drops on turbine casings at small glancing angles, as occurs near drainage belts. Analysis of the mechanisms involved is made from the records of high-speed ciné photography.


2014 ◽  
Vol 129 (S1) ◽  
pp. S45-S50 ◽  
Author(s):  
J H Kim ◽  
J Rimmer ◽  
N Mrad ◽  
S Ahmadzada ◽  
R J Harvey

AbstractObjective:This study investigated the effect of Betadine on ciliated human respiratory epithelial cells.Methods:Epithelial cells from human sinonasal mucosa were cultured at the air–liquid interface. The cultures were tested with Hanks' balanced salt solution containing 10 mM HEPES (control), 100 µM ATP (positive control), 5 per cent Betadine or 10 per cent Betadine (clinical dose). Ciliary beat frequency was analysed using a high-speed camera on a computer imaging system.Results:Undiluted 10 per cent Betadine (n = 6) decreased the proportion of actively beating cilia over 1 minute (p < 0.01). Ciliary beat frequency decreased from 11.15 ± 4.64 Hz to no detectable activity. The result was similar with 5 per cent Betadine (n = 7), with no significant difference compared with the 10 per cent solution findings.Conclusion:Betadine, at either 5 and 10 per cent, was ciliotoxic. Caution should be applied to the use of topical Betadine solution on the respiratory mucosal surface.


Author(s):  
Han Zhang ◽  
Lin Lei ◽  
Weiping Ni ◽  
Tao Tang ◽  
Junzheng Wu ◽  
...  

2021 ◽  
Vol 1 (1) ◽  
pp. 40-49
Author(s):  
S. Rachev ◽  
K. Dimitrova ◽  
D. Koeva ◽  
L. Dimitrov

During the operation of electric induction motors used to drive passenger elevators, electro-mechanical transient processes occur, which can cause unacceptable dynamic loads and vibrations. In this regard, research is needed both at the design stage and for operating elevator systems to determine the arising impact currents and torques, in order to propose solutions for their limitation within pre-set limits. Paper deals with starting processes in a two-speed induction motor drive of a passenger elevator. The equations for the voltages of the induction motor are presented in relative units in a coordinate system rotating at a synchronous speed. The values have been obtained for the torques, the rotational frequencies and the currents when starting at a high speed and passing from high to low speed.


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