中国开放科研知识云: 检索

Luminescence and energy transfer in Ca3Sc2Si 3O12:Ce3+,Mn2+ white LED phosphors (EI CONFERENCE) 会议论文
Liu Y.; Zhang X.; Hao Z.; Luo Y.; Wang X.; Ma L.; Zhang J.

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Expanded emission spectra ranging from green to red are reported in Ca 3Sc2Si3O12 (CSS):Ce 3+ Mn2+ silicate garnets. Mn2+ may occupy Ca2 site (Mn2+(I)) to generate a yellow emission band at 574 nm or Sc3 site (Mn2+(II)) with red emission band at 680 nm. Efficient energy transfers from the green emitting Ce3+ to both Mn2+(I) and Mn2+(II) occur upon blue excitation into Ce3+. Concentration dependence of Mn2+ emission is analyzed based on Ce3+-Mn2+ energy transfer steady state rate equations and fluorescence lifetimes. Energy transfer efficiency (nT) and rate (W) are calculated with values as high as 45% and 14.01106 s-1 respectively. 2011 Elsevier B.V.

Structural amelioration of 920 nm optically pumped semiconductor vertical external-cavity surface emitting laser (OPS-VECSEL) (EI CONFERENCE) 会议论文
2nd International Conference on Energy, Environment and Sustainable Development, EESD 2012, October 12, 2012 - October 14, 2012, Jilin, China
Liang X.; Wang L.; Ning Y.; Liu Y.

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920 nm optically pumped semiconductor vertical external-cavity surface emitting laser (OPS-VECSEL) has an important application in laser display. We constructed and optimized a 920 nm OPS-VECSEL with active region of In0.09Ga0.91As quantum well (QW) system pumped by 808 nm laser diode module. By the finite element method self-consistent solutions of the semiconductor electronic and optical equations are realized to calculate the characteristics parameters of OPS-VECSEL. The performances of device especially the mode the threshold and the optical-optical translation efficiency were analyzed by dealing with different number of QWs (1 2 and 3) in one period QW depth barrier width the component and dimension of the non-absorption layer. We chose an improved structure of them. On this basis we ameliorated the number of QW periods and the simulation showed that in order to obtain high performance device the choice of the number of QW periods must be cautious. (2013) Trans Tech Publications Switzerland.

Advanced astigmatism-corrected tandem Wadsworth mounting for small-scale spectral broadband imaging spectrometer (EI CONFERENCE) 会议论文
Lei Y.; Lin G.-Y.

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Tandem gratings of double-dispersion mount make it possible to design an imaging spectrometer for the weak light observation with high spatial resolution high spectral resolution and high optical transmission efficiency. The traditional tandem Wadsworth mounting is originally designed to match the coaxial telescope and large-scale imaging spectrometer. When it is used to connect the off-axis telescope such as off-axis parabolic mirror it presents lower imaging quality than to connect the coaxial telescope. It may also introduce interference among the detector and the optical elements as it is applied to the short focal length and small-scale spectrometer in a close volume by satellite. An advanced tandem Wadsworth mounting has been investigated to deal with the situation. The Wadsworth astigmatism-corrected mounting condition for which is expressed as the distance between the second concave grating and the imaging plane is calculated. Then the optimum arrangement for the first plane grating and the second concave grating which make the anterior Wadsworth condition fulfilling each wavelength is analyzed by the geometric and first order differential calculation. These two arrangements comprise the advanced Wadsworth mounting condition. The spectral resolution has also been calculated by these conditions. An example designed by the optimum theory proves that the advanced tandem Wadsworth mounting performs excellently in spectral broadband. 2012 Optical Society of America.

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

KW-output high beam quality diode laser array source (EI CONFERENCE) 会议论文
2012 International Conference on Optoelectronics and Microelectronics, ICOM 2012, August 23, 2012 - August 25, 2012, Changchun, China
Shan X.; Zhang J.; Peng H.; Fu X.; Liu Y.; Wang L.

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With the advantages of small volume light weight high efficiency and long lifespan diode laser has been widely applied to industrial processing. Presently for laser used as processing light source needs to amount to dozens of KW per cm2 of power density how to increase power output and get smaller light spot for diode laser becomes a key problem. It is introduced that by designing beam shaping by ourselves and making use of optical system for beam blooming and focusing 808nm laser array composed of 20 bars eventually achieves the 1001.5w power output coupling efficiency at 90% 11mm2 of light spot through experiments which enables diode laser to be directly applied to cladding welding and so on. 2012 IEEE.

Optimization of the two parameters of classical blaze grating in Littrow mount (EI CONFERENCE) 会议论文
2nd International Conference on Advanced Engineering Materials and Technology, AEMT 2012, July 6, 2012 - July 8, 2012, Zhuhai, China
Zhang S.; Ying J.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

On the base of electromagnetic theory of gratings we analyse the effects of both of two important parameters of classical blaze grating in Littrow mount to diffraction efficiency and the two parameters are optimized for obtaining highest diffraction efficiency. It is presented that not only blaze angle but apex angle affect diffraction efficiency. The investigation has been performed on the design and fabrication of classical blaze grating which has high diffraction efficiency. (2012) Trans Tech Publications Switzerland.

Image mosaic technique based on the information of edge (EI CONFERENCE) 会议论文
2012 3rd International Conference on Digital Manufacturing and Automation, ICDMA 2012, July 31, 2012 - August 2, 2012, Guilin, Guangxi, China
Wu Z.-G.; Wang M.-J.; Wang Y.-Q.

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Image mosaic is an important branch in the field of image processing. This paper designs and realizes an image mosaic technique based on the information of edge. The technology is suitable for engineering application. First of all two images of the adjoining frames are processed by convolution operation get the edge images. And then we cut edge image into pieces and compute their spatial frequency. According to the value of the spatial frequency select reasonable registration model group. We compute correlation strength and the value of movement offset which are the model group and the current frame edge image. We can complete image mosaic by them. We use video sequence which of the resolution is 1024 * 768 do the experiment. The results show that the method has good effect and strong adaptability. Algorithm is high efficiency which running time is 24 ms. It is suitable for real-time processing requirements of the application. This method is an effective mosaic technique which is suitable for engineering application. 2012 IEEE.

Numerical simulation on efficient spinning technology based on multi-point adjusting principle (EI CONFERENCE) 会议论文
2nd International Conference on Manufacturing Science and Engineering, ICMSE 2011, April 9, 2011 - April 11, 2011, Guilin, China
Gong X. P.

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In order to realize high efficiency and flexible manufacturing for rotary surfaces equivalent stress in sheet metal's center region and bendable rollers active region exceeds yield stress efficient spinning technology (EST) is researched. It is the combination of multi-point forming and traditional spinning. Principle of EST is described and plastic deformation is generated traditional spinning method is compared with it experimental result accords with simulation result. Feasibility of EST is validated by simulation and experimental results. (2011) Trans Tech Publications. and characteristics of it are analyzed. Finite element analysis (FEA) model of disc-shape part is established EST process is analyzed equivalent stress and plastic strain distributions are analyzed. EST equipment is developed and the experiments are made. Results indicate: EST process consists of four stages

Study on spectrograph for ionosphere: A broadband imaging instrument prototype for far-ultraviolet (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2011: Space Exploration Technologies and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Yu L.; Wang S.-R.; Lin G.-Y.

收藏 | 浏览/下载：20/0 | 提交时间：2013/03/25

Current research on space-based exploration for the ionosphere needs more advanced technologies. Because the spectral signals in the ionosphere distributing basically in the far-ultraviolet waveband are very weak. Usual spectrometer structures and detectors such as CCD can't receive enough information. Based on this principle of atmospheric sounding the imaging spectrometer prototype for ionosphere detection application was designed to solve the problem. This prototype consists of the telescope and the imaging spectrometer. The simple structure and small number of mirrors can help higher transmission efficiency be achieved and weak signals detection be implemented. The telescope is an off-axis parabolic mirror and the spectrometer is a modified Czerny-Turner spectral imaging system. Modified Czerny-Turner spectrometer contains a spherical mirror a fixed plane grating and a toroidal mirror. By adjusting the incident angle to the collimating mirror and using toroidal mirror coma and astigmatism were corrected well. We also optimize distances between the grating to the focusing mirror and the focusing mirror to the image plane to improve disadvantages of traditional Czerny-Turner structure. Designed results demonstrate that aberrations are substantially corrected and high image quality can be obtained in broad waveband. The photon counting Wedge-Strip-Anode detector with micro-channel planes as the receiving plane is accepted for the instrument prototype. The other photon counting 2-D detector responding well for weak light such as Cross-Delay line detector and MAMA detector can also be used for detection. The calibration and performances testing system is made of a vacuum system a deuterium lamp a monochrometer and the instrument prototype. Results obtained from the experiment show that the spectral resolution is 2.4 nm and the spatial resolution is 80 m. The other calibration experiments are running. The technology of the spectrometer prototype is important for the research and applications of ionosphere remote sensing. 2011 SPIE.

Research on the effect of clamp on rudder lift-drag characteristics (EI CONFERENCE) 会议论文
2nd Annual Conference on Electrical and Control Engineering, ICECE 2011, September 16, 2011 - September 18, 2011, Yichang, China
Zhang N.; Yang C.; Jia H.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

The paper introduce structured grid division use CFD numerical simulation and FLUNET software to conduct the simulation calculation for flow field of high-speed vehicle which study the clamps of high-speed vehicle control helms how to affect the lift-drag characteristics of it. To better illustrate the problem we use the canard configuration vehicle that efficiency of control is higher. This paper calculate lift-drag characteristics of outer surface of canard helm that with or without clamps in the condition of subsonic transonic and supersonic then compare the lift-drag characteristics of in different conditions and analyze from the perspective of flow field. 2011 IEEE.

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