Fan J.,Shanghai Electro Mechanical Engineering Institute |
Li L.,Shanghai Electro Mechanical Engineering Institute |
Li W.,Tianjin Jinhang Institute of Technical Physics
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2015
Infrared countermeasure systems and technology have developed for half a century. Several types of infrared countermeasure systems, such as on-board infrared jamming system, infrared decoy and infrared smoke have appeared, and form a huge family of infrared countermeasure systems. In recent years, with the development of advanced infrared imaging guided weapons and technology, the jamming performance of traditional infrared countermeasure systems became more and more dissatisfactory. The technical concept of direct infrared countermeasure (DIRCM) was gradually proposed, which used high-power Xenon lamp or laser as sources of infrared energy. DIRCM has advantageous infrared countermeasure properties, such as the capability of jamming infrared imaging seeker by jamming, dazzling, in-band damaging and out-ofband damaging, etc, the capability of reuse and high jamming efficiency, which makes it suitable for new generation of infrared countermeasure system. The international research on DIRCM systems and technology in recent years was reviewed. And the operational principle, jamming damage mechanism, technology advantage of DIRCM system and the development status abroad were focused. And the research trends of DIRCM system and technology were forecasted in the next years. ©, 2015, Chinese Society of Astronautics. All right reserved.
Chen D.,Harbin Institute of Technology |
He P.,Harbin Institute of Technology |
He P.,Harbin University of Commerce |
Fan R.,Harbin Institute of Technology |
And 4 more authors.
Journal of Physical Chemistry C | Year: 2012
We utilize femtosecond time-resolved electronic resonance-enhanced coherent anti-Stokes Raman scattering (ERE-CARS) to study the vibrational dynamics of cresyl violet 670 (CV670) dye molecules. For this purpose, the vibrational properties of CV670 are registered in diluted solutions of ethanol and methanol. By changing the timing (Δt > 0) of the laser pulses of this nondegenerate four wave mixing technique, the wavepacket dynamics on the electronically ground state can be detected as oscillations in the ERE-CARS signal. Two strong Raman vibrational modes with an average period of 0.401 and 0.423 ps in CV670-ethanol solutions are obtained simultaneously, and we observe a qualitative vibrational dephasing time difference of the Raman vibrational modes of CV670 in ethanol and methanol solvents (5 × 10 -5 mol/L), which may be due to the influence of the formation of the supramolecular structures in CV670-ethanol and CV670-methanol mixtures on the Raman modes of CV670. © 2012 American Chemical Society.
Wang J.-H.,Tianjin Jinhang Institute of Technical Physics |
Yao H.-B.,Tianjin Jinhang Institute of Technical Physics |
Liu Z.-X.,Tianjin Jinhang Institute of Technical Physics
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2010
The laser emitting circuit is an important part of laser proximity fuze system of which the characteristic affects the performance of laser proximity fuze directly. To gain the laser pulse with high-power and short-pulse, it is important to improve the operation distance, the dynamic detection accuracy and the ability of anti-interference of fog. But, there are many actual problems on gaining the laser pulse with high-power, short-pulse and small volume. When the laser pulse's width is becoming narrow to some certain, the peak power of laser pulse falls, which is influenced by the laser, driving circuit distributing parameter, process technology, and so on. In this paper, first of all, the laser emitting circuit was analyzed theoretically, secondly, PSPICE model and simulated waves were built. The results show that the parasitic inductance of laser and stray parameter of discharge loop may affect the frontier velocity of laser pulse and peak power. The relative solution methods were given from driven circuit design, components and laser selection, and circuit board layout.
Liu Q.,Tianjin Jinhang Institute of Technical Physics |
Wang L.-Q.,Tianjin Jinhang Institute of Technical Physics
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011
Airborne laser scanning (ALS) is an active remote sensing technique that can provide 3D information about the scene. Over the last few years, ALS has proved its capability of rapid acquisition of accurate topographic data. With the advantages of high accuracy, ALS data has become an accepted data source for highly automated acquisition of digital surface models (DSM) as well as for the generation of digital elevation models (DEM) which have been used in many applications such as civic planning, military navigation and natural hazard risk assessment. To utilize the 3D data provided by the ALS systems however, efficient methods for data processing and model construction needs to be developed. In this paper some recent technique on analysis and visualization modelling of ALS data will be presented. After the brief presentation of the ALS system, the computation of ALS data is introduced. The data processing chain for producing DSM is outlined. A data filtering method is proposed for generating DEM. A 3D visualization modelling study on ground scene is carried out and the framework of establishing visualization of DSM and DEM using ALS data is brought as well. © 2011 SPIE.
Liu H.-S.,Tianjin Jinhang Institute of Technical Physics |
Wang L.-S.,Tianjin Jinhang Institute of Technical Physics |
Jiang Y.-G.,Tianjin Jinhang Institute of Technical Physics |
Ji Y.-Q.,Tianjin Jinhang Institute of Technical Physics
Guangxue Jingmi Gongcheng/Optics and Precision Engineering | Year: 2013
The effects of preparative parameters such as substrate temperature, ion beam voltage, ion beam current and oxygen flow on the refractive index and stress of a SiO2 thin film were systematically studied by using the orthogonal experiment design method. The transmittance spectrum of SiO2 thin film was measured by spectrophotometers, and its reflective ellipsometric characteristics were measured by an elliptical polarization instrument. Then, the refractive index and stress of the thin film were obtained by the multiple wavelength curve-fitting method and the elastic deformation of a thin film-substrate system, respectively. The experimental results show that the refractive indexes of SiO2 thin film affected by preparative parameters with the weights from high to low are in a sequence of oxygen flow, substrate temperature, ion beam current and ion beam voltage and the confidence probability of effects of the first three refractive indexes is 87.03%, 71.98% and 69.53%, respectively. Moreover, the stresses of SiO2 thin film affected by preparative parameters with the weights from high to low are in a sequence of substrate temperature, ion beam current, ion beam voltage and oxygen flow and the confidence probability of effects of the first three stresses is 95.62%, 48.49% and 37.88%, respectively. It suggests that higher oxygen flows, lower substrate temperatures and lower ion beam voltages should be selected for preparing SiO2 thin films with low refractive indexes and lower substrate temperatures, and higher oxygen flows for preparing SiO2 thin films with low stresses.
Shen S.,Tianjin Jinhang Institute of Technical Physics
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2012
Microsystem is a comprehensive course based on Micro-Electro-Mechanical Systems, manufacturing technology of integrated circuit and other sciences, which is minitype, integrated, intelligent, inexpensive, efficient and productive. The composing and principle on microsystem domestic and oversea were described, the history and status on development of microsystem and distribution of industry were also introduced. Kinds of significant technologies on the machining of micro-structure instrument were presented and the principle, characteristic and technic in wet-etching, deep dry-etching, surface processing, binding, LIGA technology, nanoimprint technology and technology of producting high aspect ratio structures (HARPSS) were analyzed. HARPSS can make devices three-dimensional. Extraordinarily LIGA, which utilizes the excellent permeability of X-ray, can make high aspect ratio greater than 200:1, so that the size of structures can be smaller. The advantages of every technology combined with typical micro device were also pointed out such as mini-capacitor microphone and gear wheel.
Li J.,Tianjin University |
Du Z.,Tianjin University |
Zhou T.,Tianjin Jinhang Institute of Technical Physics |
Zhou K.,Tianjin Jinhang Institute of Technical Physics
Proceedings of 2012 International Conference on Measurement, Information and Control, MIC 2012 | Year: 2012
A technique has been developed to obtain simultaneous tomographic images of temperature and species concentration based on line-of-sight (LOS) diode laser absorption spectroscopy. Multiple LOS measurement paths divide the combustion zone into an MxN grid. With the assumption of uniform distribution around the grid intersection points, spatial distribution of temperature or a particular chemical species can be inferred from the M+N path averages because each measurement path passes through different grid boxes and carries their information of temperature and species concentration. The measurement accuracy and resolution depend on the total number of paths measured. The feasibility of this method is verified by simulated image reconstruction of an engine temperature distribution. © 2012 IEEE.
Yu Z.,Beijing Institute of Technology |
Leng J.,Beijing Institute of Technology |
Leng J.,Tianjin Jinhang Institute of Technical Physics |
Xue W.,Beijing Institute of Technology |
And 4 more authors.
Applied Surface Science | Year: 2012
ZnS/Ag/ZnS (ZAZ) multilayer films were prepared on polyethene terephthalate (PET) by ion beam assisted deposition at room temperature. The structural, optical and electrical characteristics of ZAZ multilayers dependent on the thickness of silver layer were investigated. The ZAZ multilayers exhibit a low sheet resistance of about 10 Ω/sq., a high transmittance of 92.1%, and the improved resistance stabilities when subjected to bending. When the inserted Ag thickness is over 12 nm, the ZAZ multilayers show good resistance stabilities due to the existence of a ductile Ag metal layer. The results suggest that ZAZ film has better optoelectrical and anti-deflection characteristics than conventional indium tin oxide (ITO) single layer. © 2011 Elsevier B.V. All rights reserved.
To S.,Hong Kong Polytechnic University |
Zhu Z.,Hong Kong Polytechnic University |
Wang P.,Tianjin Jinhang Institute of Technical Physics
Optical Engineering | Year: 2015
To improve the quality of diamond turned optics, it is necessary to employ a laborious postprocessing approach. However, the approach is often very hard to implement on freeform surfaces, and it greatly decreases the processing efficiency even for simple optics. An evolutionary diamond turning method is first proposed to comprehensively improve the quality of the turned optics. The evolutionary goal is to attenuate the peak value of the power spectral density of residual tool marks, and the special mutation point is observed during the evolution. Taking advantage of the modulation operation of a diamond tool in the spatial frequency domain, form accuracy, surface roughness, and surface reflectivity are all significantly improved, demonstrating the superiority of the EDT method for optics fabrication. © 2015 Society of Photo-Optical Instrumentation Engineers.
Dong H.,Tianjin Jinhang Institute of Technical Physics |
Liu H.,Tianjin Jinhang Institute of Technical Physics
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2015
An aviation large field of view(FOV) infrared scanning device employs TDI-CCD detector and performs a complete appliance scanning manner, its imaging quality is influenced by aircraft yawing rotation. The scanning device line of sight (LOS) rotation equation and LOS rotation constraint equation were established through kinematic analysis. Thus the aircraft yawing rotation bound was obtained which allowed a distinct image quality. Simulation was carried out on actual flight data, it shows an excellent image quality when aircraft makes a straight flight. The aircraft yawing rotation influence to large FOV scanning is acceptable. ©, 2015, Chinese Society of Astronautics. All right reserved.