中国科学院机构知识库网格系统: 检索

Lightweight design of large scale theodolite's turntable based on topology optimization of continuum structure (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Optoelectronics and Microelectronics, ICOM 2012, August 23, 2012 - August 25, 2012, Changchun, China
作者: Wang Y.; Wang Y.; Wang Y.; Wang Y.; Wang Y.

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In order to solve the problem that the weight of large scale theodolite's casting or steel plate welded structure is too heavy lightweight design of large scale turntable based on topology optimization of continuum structure is investigated. Topology optimization could have better optimization efficiency because it can provide the optimized distribution of material and gain optimized structure in conceptual design phase of the structural design. In order to obtain lightweight and high stiffness structure a truss turntable based on topology optimization of continuum structure is presented and the validity of this lightweight structure is examined by finite element analysis. Comparing to the traditional welding steel turntable the lightweight turntable without changing the static displacement can lose 386.48 kg(lightweight ratio is 26.7%) and its first-order natural frequency raises from 167.02Hz to 173.71Hz. Meanwhile in other aspects this turntable also has better performance than traditional structure. 2012 IEEE.

Optimization and design of the bottom support of the primary mirror chamber in the opto-electronic device (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Transportation, Mechanical, and Electrical Engineering, TMEE 2011, December 16, 2011 - December 18, 2011, Changchun, China
作者: Zhang G.; Zhang G.; Zhang G.

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Application of particulate reinforced aluminum matrix composite in airborne photoelectric turret (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Electric Information and Control Engineering, ICEICE 2011, April 15, 2011 - April 17, 2011, Wuhan, China
作者: Wang P.

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In order to design and manufacture more excellent airborne photoelectric stable turret modulus of elasticity of 213 GPa and thermal expansion coefficient of 7.9106/K. The frame has decreased the maximum deformation by by 60% and increased the fundamental frequency by 65% as compared with those of aluminum alloy materials a new type of aeronautical material-particulate reinforced aluminum matrix composite (SiC/Al composite) is investigated. Several crucial technologies respectively as shown by finite element analysis results. Those are confirmed by vibration test furthermore. Therefore such as pressureless infiltration technology a significant lightening effect is achieved and the thermal control load is also reduced. The test result indicates that the stable accuracy of the system achieves 19.8rad and the optical-axis parallelism of pay load is 0.1mrad. The research applies the SiC/Al composites to airborne photoelectric platforms interface reaction controls and plate's welding are systematically studied. Then which makes a effective exploration for the new aeronautical material's application. 2011 IEEE. using SiC/Al composites the airborne photoelectric stable turret frame is successfully prepared in density of 2.94 g/ cm3

Design and image restoration research of a cubic-phase-plate system (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies, April 26, 2010 - April 29, 2010, Dalian, China
作者: Zhang J.; Zhang J.; Zhang J.; Shi G.; Zhang X.

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Wave-front coding technology is a novel jointly optical and digital imaging technology which can greatly extend the depth of focus of optical systems. The image restoration process is an important part of wave-front coding technology. Using wave-front coding makes the modulation transfer function(MTF) values of the optical systems change little over a range of several times the depth of focus which means the system MTF is quite insensitive to defocus and there is no zero in the passband. So we can design a single filter for the restoration of images in different defocus positions. However it's hard to avoid noise during image acquisition and transmission processes. These noises will be amplified in the image restoration especially in the high frequency part when the MTF drop is relatively low. The restoration process significantly reduces the system signal to noise ratio this way. Aimed at the problem of noise amplification a new algorithm was proposed which incorporated wavelet denoising into the iterative steps of Lucy-Richardson algorithm. Better restoration results were obtained through the new algorithm effectively solving the noise amplification problem of original LR algorithm. Two sets of identical triplet imaging systems were designed in one of which the cubic-phase-plate was added. Imaging experiments of the manufactured systems were carried and the images of a traditional system and a wave-front coded system before and after decoding were compared. The results show that the designed wave-front coded system can extend the depth of focus by 40 times compared with the traditional system while maintaining the light flux and the image plane resolution. 2010 Copyright SPIE - The International Society for Optical Engineering.

Motion mechanism analysis of a two-degree-of-freedom spherical motor (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Information Engineering and Computer Science, ICIECS 2010, December 25, 2010 - December 26, 2010, Wuhan, China
作者: Guo K.

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The working principle of a two-degree-of-freedom piezoelectric spherical motor using only one piezoelectric element was analyzed. The resonance frequencies of the motor's plate type piezoelectric vibrator were calculated by finite element method. The computer simulation was executed to analyze the motion trajectory of the four contact points between the stator and the sphere. Simulation results verified that the four contact points can form timing reasonable elliptical trajectories which re designed to drive the sphere to form two rotation degrees of freedom. The conclusion indicated the formation of two-dimensional movement mechanism of the spherical motor. 2010 IEEE.

Disc varifocal mechanism to improve efficiency of scene matching navigation system (EI CONFERENCE) 会议论文 OAI收割
2009 2nd International Conference on Future Information Technology and Management Engineering, FITME 2009, December 13, 2009 - December 14, 2009, Sanya, China
作者: Zhang C.-L.

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In order to meet special requests of optical imaging sensor in scene matching navigation system a disc varifocal mechanism is proposed for the flight vehicles of long flying time and range. Within small space occupied it can obtain real images with various resolutions. Moreover using plate traveling-wave Ultrasonic Motor as its driven motor can reduce energy loss improve control precision and ensure image obtaining being real-time and stable. Disc varifocal mechanism driven by plate traveling-wave Ultrasonic Motor is high-response and variation in load doesn't affect its performance parameter. Therefore applying disc varifocal mechanism in scene matching navigation system combing software and hardware can obviously improve the accuracy real-time and robust of scene matching navigation system. The experiment showed that when the weight of mechanism was 1.5kg the shortest starting was 0.6ms and the shortest shutoff was 0.5ms. 2009 IEEE.

The cell thickness and twist angle measurement of twist nematic liquid crystal cell by rotation of a quarter-wave plate using fourier analysis method (EI CONFERENCE) 会议论文 OAI收割
Asia Display 2007, AD'07, March 12, 2007 - March 16, 2007, Shanghai, China
Cui H.-Q.; Ling Z.-H.

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Proposed a new method of determining the cell thickness and the twist angle of twisted nematic liquid crystal cells a quarter-wave plate was inserted between the liquid crystal cell and the analyzer a stepper motor rotated the Retarder by 360 and measured the light intensity of every modulated point solved the stokes parameters of polarization light exiting from the liquid crystal cell using Fourier analysis method thereby determining the cell thickness and the twist angle. Experiments indicated that it is suitable for measuring the low-cell-gap accurately. In addition it also can be applied to the measurement of the cell thickness and twist angle of single polarizer reflected liquid crystal cell.

Study of microsphere plate photomultiplier tube (EI CONFERENCE) 会议论文 OAI收割
ICO20: Remote Sensing and Infrared Devices and Systems, August 21, 2005 - August 26, 2005, Changchun, China
作者: Wang X.; Li Y.; Li Y.; Li Y.; Li Y.

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The photomultiplier tube (PMT) that can work in different wavelength is an important detector device in remote sense technology. Microsphere plate using glass beads 50to 70m in diameter sintered together is the core component of the microsphere plate photomultiplier tube It is a novel two-dimension electron multiplier. The electrons gain for a single plate is about 1017 and do not have the phenomenon of ion-feedback. Furthermore the fabrication process is very easy. In this paper much interest was put on the microsphere plate photomultiplier tube. Based on the analyses from the theory and the experiment result we point out the key technology for fabricating PMT is how to obtain glass beads with narrow range in diameter and how to sinter the glass beads with a sufficient pylome. Factors affect the gradating technology and sintering process along with the solution to them is presented. In the last the structure scheme and technological characteristic for fabricating microsphere plate photomultiplier tube were given. The pulse rising-time of MSP-PMT is below 400ps suitable to the detection of high-speed pulse. As easy to be fabricated and has great advantage over MCP multiplier in the ratio of performance to price the microsphere plate photomultiplier tube is a promising dim-light detector.

Fabrication of polysilicon thin film on glass with low-temperature UV-assisted crystallization (EI CONFERENCE) 会议论文 OAI收割
ICO20: Display Devices and Systems, August 21, 2005 - August 26, 2005, Changchun, China
Huang J. Y.; Ling Z. H.; Jing H.; Fu G. Z.; Zhao Y. H.

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The amorphous silicon (a-Si) film was crystallized on glass by a simple method employed ultraviolet at temperatures as low as 400C. The employ of ultraviolet enhanced the crystallization of amorphous silicon. This method is able to uniformly crystallized large-area amorphous silicon films. The polysilicon films crystallized by this way are suitable for the fabrication of thin film transistors on ordinary glass. Crystallization process is performed in a furnace. Amorphous silicon sample is placed on a hot plate and irradiated by a bank of ultraviolet lamps through a diffuser plate to improve the uniformity of light that irradiates the sample. Raman microscopy is used for analyzing the qualities of UV-assisted crystallized silicon films. By measuring the Raman spectra the effects of anneal temperature and process time on the crystallizing behavior crystallinity and grain size of the processed films were obtained. There has a threshold temperature for crystallization of amorphous silicon film in the presence of ultraviolet irradiation with certain intensity i.e. by ultraviolet irradiation with certain intensity only when the temperature is up to the threshold temperature the crystallization can be triggered. The threshold temperature is 400C when the intensity of ultraviolet irradiation is 1mW/cm2. Above threshold temperature the increase of anneal temperature increased the rate of crystallization. Crystallinity and grain size extracted from Raman spectra of samples increase with the extending of process time at certain temperature. Crystallization of amorphous silicon film with thickness of 50nm completed within 6 hours at 400C irradiated by ultraviolet with intensity of 2mW/cm2.

Fabrication and electron emission of carbon microtubes (EI CONFERENCE) 会议论文 OAI收割
Technical Digest of the 18th International Vacuum Nanoelectronics Conference, IVNC 2005, July 10, 2005 - July 14, 2005, Oxford, United kingdom
作者: Liu L.; Liu L.; Wang W.; Wang W.

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Carbon nanotubes have been attracting attention because of their unique physical properties and their application potential for field emission cathode. Carbon nanotubes possess the following properties favorable for field emission material such as a high aspect ratio and sharp tip high chemical stability high mechanical strength stable at high temperature. Some research works on carbon nanotubes field emitter and field emission display have been reported. Here a kind of carbon microtubes and its field emission properties are introduced. They have some different properties with carbon nanotubes and the density is lower than carbon nanotubes bundles. These carbon microtubes are directly synthesized by liquidoid epitaxy method on silicon substrates at low temperature. The field emission properties of carbon microtubes are reported too. Carbon microtubes film is synthesized in liquid by electrolysis. The graphite plate is as anode and n-silicon substrate with resistivity of 4-8 cm is as cathode. The electrolysis current is about 5-8mA/cm2 and applied voltage is 800-1500V. Temperatures of the methanol base solution is maintained at 60C in process of deposition of carbon microtubes. Carbon microtubes film is observed by scanning electron microscopy(SEM) as shown in fig.1(a b). The wall's thickness of carbon microtube is about 60nm. The diameter of carbon microtube is about 0.8 m. Raman spectrum of carbon microtubes film shows the two peaks at 1342and 1560cm-1. The field emission properties of carbon microtubes are measured in high vacuum chamber(10-5Pa). The emission area of carbon microtubes is 0.5cm 0.5cm. The threshold of field emission of the carbon microtubes film is about 3.6V/ m. Field emission property of carbon microtubes film is shown in fig.2. Another when the electric field between anode and cathode is 10V/ m the electric field distribution on single carbon microtube is also given after calculation according to electric field theory. Fig 3 shows that electric field distribution vertical section on the of single carbon microtube top with 2 m of highness. These results may help us to understand field emission properties of carbon microtubes. According to research results it is found that liquidoid synthesis is simple method to produce carbon microtubes cold cathode material and the carbon microtubes have better field emission properties. 2005 IEEE.