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.

Tribological properties of Mos2 thin coatings under liquid lubricating (EI CONFERENCE) 会议论文
2nd International Conference on Innovation Manufacturing and Engineering Management, IMEM 2012, December 14, 2012 - December 16, 2012, Chongqing, China
Bai Y.; Cao P.

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The objective of this study is to investigate the effect of solid and liquid lubrication on friction and wear performance of selected solid lubricating coatings comparative experiments have been carried out on magnetron sputtered MoS2 coatings against Si3N4 ball using a ball-on-disk tribo-tester under the conditions of room temperature and different lubrication. Surface morphology of coatings were investigated by atom force microscope (AFM) and friction coefficient (COF) and wear rate of solid films were also be analyzed. It was shown that the friction is greatly reduced when the solid film is lubricated with oil and grease simultaneously in comparison with single-lubricant lubrication at the start-up or under boundary lubrication conditions. Liquid lubrication causes a dramatic decrease of the wear-ability of the MoS2 coatings. The effect of oil lubrication to the deterioration of wear resistance of MoS2 film was even worse than lubrication grease. (2013) Trans Tech Publications Switzerland.

Laser cleaning of neutral attenuator plate based on low power laser diode (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
Gan X.; Chen Y.; Li L.

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Laser cleaning is a non-contact green and environmental cleaning method which can effectively remove particulate contaminations of sizes as small as 0.1 m without damage to the optics. But most laser cleaning devices are large and heavy also expensive due to using large lasers such as CO2 laser YAG Laser etc. In this work a low power LD was tried to clean fingerprint and dust contaminated on the surface of the attenuator glasses plates. In the laser cleaning experiment with low power diode the fingerprint grease can be efficient to be cleaned but there is no evident effect for cleaning inorganic dust. The cleaning different degree of fingerprint contaminations was investigated at the variable laser parameters including laser power and irradiation time. An optical microscope was used to analyze the cleaning effect. The results show that low power LD can effectively remove the fingerprint on the surface of absorptive-type attenuator glass plates. On the premise that the attenuator optics glasses are not damaged the cleaning area increases with the increase of radiation time and laser power. The cleaning area doesn't change much with the variation of laser frequency when the other parameters are the same. (2013) Trans Tech Publications Switzerland.

Electrically pumped organic laser device with a coupled microcavity structure (EI CONFERENCE) 会议论文
Organic Light Emitting Materials and Devices XVI, August 12, 2012 - August 15, 2012, San Diego, CA, United states
Liu X.; Lin J.; Li Y.; Qu S.

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Lasing action in electrically pumped organic laser device is demonstrated. A DCM laser dye doped Alq film serves as the active layer. High reflective and low loss electrical contacts are used to form a high quality factor coupled microcavity. Single longitudinal cavity mode is obtained at 618 nm with a threshold current density of 612 mAcm-2 under room temperature continuous wave operation. 2012 SPIE.

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.

Influence of high temperature annealing in nitrogen on upconversion luminescence of -NaYF4: Yb3+, Er3+ hexagonal sub-microplates (EI CONFERENCE) 会议论文
2012 International conference on Function Materials and Nanotechnology, FMN 2012, May 19, 2012 - May 20, 2012, Zhengzhou, China
Zhao J.; Jia T.; Kong X.

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The pure -NaYF4: Yb3+ Er3+ hexagonal sub-microplates were successfully prepared by the combination of coprecipitation and hydrothermal methods using sodium citrate as chelator. The size of them is about 600 nm 400 nm (side length thickness). The obtained sample was divided into two parts and one of them was annealed in nitrogen at 300 C for 2 hours. The crystal structure of the -NaYF4: Yb3+ Er3+ hexagonal sub-microplates before and after annealing treatment is hexagonal phase. Under the excitation of 980 nm diode laser the upconversion luminescence intensity the sample after annealing is much stronger than that of the sample without annealing treatment. High temperature annealing process improved the crystallization of the sample resulting in the decrease of the nonradiative relaxation and the enhancement of the upconversion luminescence. (2012) Trans Tech Publications Switzerland.

Influence of sensitizer concentration on the upconversion luminescence of NaYF4: Yb3+, Er3+ nanoparticles (EI CONFERENCE) 会议论文
2012 2nd International Conference on Machinery, Materials Science and Engineering Applications, MMSE 2012, June 16, 2012 - June 17, 2012, Wuhan, China
Zhao J.; Shi D.; Zhao Y.; Kong X.

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A series of NaYF4: Yb3+ Er3+ nanoparticles with different doping concentration were successfully prepared by the combination of coprecipitation and hydrothermal methods using sodium citrate as chelator. Upconversion luminescence can be observed in all of the samples at room temperature. Fixed the Er3+ concentration with 1 mol% unchanged the effect of the Yb3+ concentration on the upconversion luminescence of NaYF4: Yb3+ Er3+ samples were studied when the doped Yb3+ concentrations were 0 mol% 1 mol% 2 mol% 5 mol% 10 mol% and 20 mol% respectively. As increasing the Yb 3+ concentration the total intensity of the upconversion luminescence of the samples is increasing while the ratio of red to green emission increases firstly and then decreases. The maximum ratio value is 22.1 when the Yb3+ concentration is 10 mol%. It is found that the cross relaxation and cooperative sensitization effect are the reasons for the phenomenon above. (2012) Trans Tech Publications.

Control of N/N2 species ratio in NO plasma for p-type doping of ZnO (EI CONFERENCE) 会议论文
Chen X.; Zhang Z.; Yao B.; Jiang M.; Wang S.; Li B.; Shan C.; Liu L.; Zhao D.; Shen D.

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Nitrogen-doped ZnO thin films were grown on c-plane sapphire (Al 2O3) substrates via plasma-assisted molecular beam epitaxy using plasma activated nitric oxide (NO) as the oxygen source and dopant. X-ray diffraction measurements indicate that a small NO flux benefits the crystal quality of the thin films. Hall effect measurements indicate that the electron density of the ZnO films decreases gradually with decreasing NO flux and the conduction reverses to p-type at a certain flux. Optical emission spectra indicate that the N atom content in the NO plasma increases with decreasing NO flux and the origin of this is discussed. X-ray photoelectron spectroscopy measurements demonstrate that the number of N atom occupied O sites in the ZnO lattice increases correspondingly. 2011 American Institute of Physics.

Design of motion compensation mechanism of satellite remote sensing camera (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
Gu S.; Yan Y.; Xu K.; Jin G.

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Synthesis and luminescence properties of Eu3+-doped silicate nanomaterial (EI CONFERENCE) 会议论文
17th International Conference on Dynamical Processes in Excited States of Solids, DPC'10, June 20, 2010 - June 25, 2010, Argonne, IL, United states
Lu S.; Zhang J.; Zhang J.

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In this paper we introduce a sol-gel process for preparing Y 2Si2O7: Eu3+ nanocrystals. The rare earth compounds were dispersed in the SiO2 colloids and the monodisperse nano-scale composite materials were prepared. The reactant mass fraction and heat treatment temperatures could affect the structures and emission spectrum properties of as-synthesized samples. The samples emit the strong red light upon excitation under the ultraviolet. The main peaks originate from 5D0-7F2 electric dipole transition of Eu3+. With regard to the samples treated at different temperatures the emission spectra obtained under 266 nm excitation show different shapes of spectra lines and relative intensities indicating that the Eu3+ ions have been located in different local environments. 2011 Published by Elsevier B.V.

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