Influence of aerodynamic optics on the imaging quality degradation of an high-speed aircraft

2018 ◽  
Author(s):  
Shouqian Chen ◽  
Rongda Zhang ◽  
Yue Ming ◽  
Lin Ju ◽  
Baofeng Cao ◽  
...  
Keyword(s):  
High Speed ◽  
Imaging Quality ◽  
Quality Degradation

Aerodynamic heating of the dome on imaging quality degradation of conformal optical systems

Optik ◽  
2014 ◽  
Vol 125 (24) ◽  
pp. 7120-7125 ◽  
Author(s):  
Wang Zhang ◽  
Fanyang Dang ◽  
Chenglong Hao ◽  
Zhigang Fan
Keyword(s):  
Optical Systems ◽  
Aerodynamic Heating ◽  
Imaging Quality ◽  
Quality Degradation

Joint influences of aerodynamic flow field and aerodynamic heating of the dome on imaging quality degradation of airborne optical systems

2012 ◽  
Vol 51 (36) ◽  
pp. 8625 ◽  
Author(s):  
Haosu Xiao ◽  
Baojun Zuo ◽  
Yi Tian ◽  
Wang Zhang ◽  
Chenglong Hao ◽  
...  
Keyword(s):  
Flow Field ◽  
Optical Systems ◽  
Aerodynamic Heating ◽  
Imaging Quality ◽  
Quality Degradation

scholarly journals Analysis of Hypersonic Platform-Borne SAR Imaging: A Physical Perspective

2021 ◽  
Vol 13 (23) ◽  
pp. 4943
Author(s):  
Lihao Song ◽  
Bowen Bai ◽  
Xiaoping Li ◽  
Gezhao Niu ◽  
Yanming Liu ◽  
...  
Keyword(s):  
High Speed ◽  
Signal Propagation ◽  
High Plasma ◽  
Plasma Sheath ◽  
Plasma Parameters ◽  
Sar Images ◽  
Scatter Matrix ◽  
Imaging Quality ◽  
Imaging Results ◽  
Sar Imaging

The usage of a hypersonic platform for remote sensing application has promising prospects, especially for hypersonic platform-borne synthetic aperture radar (SAR) imaging. However, the high-speed of hypersonic platform will lead to extreme friction between the platform and air, which will cause the ionization of air. The ionized gas forms the plasma sheath wrapped around the hypersonic platform. The plasma sheath will severely affect the propagation of SAR signal and further affect the SAR imaging. Therefore, hypersonic platform-borne SAR imaging should be studied from a physical perspective. In this paper, hypersonic platform-borne SAR imaging under plasma sheath is analyzed. The SAR signal propagation in plasma sheath is computed using scatter matrix method. The proposed SAR signal model is verified by using a ground experiment system. Moreover, the effect of attenuation caused by plasma sheath on SAR imaging is studied under different SAR parameters and plasma sheath. The result shows that attenuation caused by plasma sheath will degrade the SAR imaging quality and even cause the point and area targets to be submerged into the noise. The real SAR images under plasma sheath also illustrate this phenomenon. Furthermore, by studying imaging results under different SAR and plasma parameters, it can be concluded that the severe degradation of SAR imaging quality appears at condition of high plasma sheath electron density and low SAR carrier frequency. The work in this paper will be beneficial for the study of hypersonic platform-borne SAR imaging and design of hypersonic SAR imaging systems in the future.

Prevention of Material Deterioration in ECM of Sintered Carbide with Iron Ions

2017 ◽  
Vol 11 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Akihiro Goto ◽  
◽  
Atsushi Nakata ◽  
Sicong Wang ◽  
Nagao Saito ◽  
...  
Keyword(s):  
High Speed ◽  
Electrochemical Machining ◽  
High Speed Machining ◽  
Conductive Liquid ◽  
Sintered Carbide ◽  
High Speeds ◽  
Quality Degradation ◽  
Fe Ions ◽  
Electrical Source

This study focuses on electrochemical machining as a method of processing sintered carbide at high speeds. Previous studies have suggested the possibility of using electrochemical machining to achieve high-speed machining of sintered carbide. However, there has been strong resistance in industry against bringing sintered carbide into contact with a conductive liquid. This is because the material quality of sintered carbide is degraded by the elution of Co when it is brought into contact with a conductive liquid.In previous reports, the authors have shown that it is possible to control two modes of Co elution occurring during electrochemical machining: the elution from sintered carbide when it comes into contact with an electrolyte, and the selective elution of Co due to difference in the speeds of WC dissolution and elution of Co when sintered carbide is connected to an electrical source for processing. It was shown that it is possible to control the elution Co in sintered carbide when it comes into contact with an electrolyte by adding Co ions to the electrolyte to increase the concentration of Co ion, and that it is possible to prevent the excessive elution of Co by using a bipolar electrical source for machining. Although we showed that it is possible to carry out electrochemical machining of sintered carbide without degrading its quality, adding of large amounts of Co ions to the electrolyte entails a high cost. In this report, therefore, we describe the addition of Fe ions instead of Co ions to perform electrochemical machining of sintered carbide without quality degradation.

Comprehensive analysis of imaging quality degradation of an airborne optical system for aerodynamic flow field around the optical window

2013 ◽  
Vol 52 (33) ◽  
pp. 7889 ◽  
Author(s):  
Chenglong Hao ◽  
Shouqian Chen ◽  
Wang Zhang ◽  
Jinhan Ren ◽  
Chong Li ◽  
...  
Keyword(s):  
Flow Field ◽  
Optical System ◽  
Comprehensive Analysis ◽  
Optical Window ◽  
Imaging Quality ◽  
Quality Degradation

Technique of Adaptive Dynamic Imaging Quality Compensation for Dynamic Optics Working for High-speed Aircraft

2015 ◽  
Vol 44 (2) ◽  
pp. 211001
Author(s):  
李岩 LI Yan ◽  
胡斌 HU Bin ◽  
庄绪霞 ZHUANG Xu-xia
Keyword(s):  
High Speed ◽  
Dynamic Imaging ◽  
Imaging Quality ◽  
Adaptive Dynamic

Influence of altitude on aero-optic imaging quality degradation of the hemispherical optical dome

2019 ◽  
Vol 58 (2) ◽  
pp. 274 ◽  
Author(s):  
Hui Wang ◽  
Shouqian Chen ◽  
HuaJun Du ◽  
Fanyang Dang ◽  
Lin Ju ◽  
...  
Keyword(s):  
Imaging Quality ◽  
Quality Degradation

Microfabrication research at the National Submicron Facility

1983 ◽  
Vol 41 ◽  
pp. 86-89
Author(s):  
E.D. Wolf
Keyword(s):  
Integrated Circuits ◽  
Particle Physics ◽  
High Speed ◽  
New Technology ◽  
High Energy ◽  
High Energy Particle ◽  
New Science ◽  
Wide Range ◽  
Intermediate Domain ◽  
Circuit Function

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.

Vacuum System to Minimize the Specimen Contamination of High-Performance EM

1977 ◽  
Vol 35 ◽  
pp. 68-69
Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh
Keyword(s):  
Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
High Vacuum ◽  
Vacuum System ◽  
Pump System ◽  
Pumping System ◽  
Diffusion Pump ◽  
Almost All ◽  
Cascade Type

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.

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