16 results on '"Xu, Tie"'
Search Results
2. Investigation of 2.9 μm luminescence properties and energy transfer in Tm3+/Dy3+ co-doped chalcohalide glasses
- Author
-
Shixun Dai, Xianghua Zhang, Qiuhua Nie, Xiang Shen, Xu Tie-Feng, Xunsi Wang, Zhongxiu Li, coll informat Sci & Engn Ningbo, Ningbo University (NBU), Jiangxi Agr Univ, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
- Subjects
Absorption spectroscopy ,Energy transfer ,Analytical chemistry ,02 engineering and technology ,01 natural sciences ,7. Clean energy ,Ion ,law.invention ,010309 optics ,Geochemistry and Petrology ,law ,0103 physical sciences ,energy transfer ,rare earths ,luminescence properties ,Chemistry ,Resonance ,[CHIM.MATE]Chemical Sciences/Material chemistry ,General Chemistry ,021001 nanoscience & nanotechnology ,Laser ,chalcohalide glasses ,0210 nano-technology ,Luminescence ,Co doped ,Excitation ,Tm3+/Dy3+ - Abstract
A series of chalcohalide glasses based on the composition of 0.9(Ge 30 Ga 5 Se 65 )-0.1CsI with different Tm 3+ /Dy 3+ -codoped ions concentrations were synthesized by melt-quenching technique. The absorption spectra and 2.9μm mid-infrared fluorescence spectra of glass samples under 800 nm laser excitation were measured. The results showed that Tm 3+ was an efficient sensitizer, which could enhance the Dy 3+ :2.9 μm fluorescence intensity significantly. The effective energy transfer between the two rare-earth ions were mainly attributed to the resonance energy transfer from Tm 3+ : 3 F 4 to Dy 3+ : 6 H 11/2 level. Emission cross section of 2.9 μm mid-infrared luminescence was also investigated according to Judd-Ofelt theory, σ e =2.51×10 −20 cm 2 .
- Published
- 2011
3. Filtration and Pulse Cleaning System for Particle Removal from Gas
- Author
-
Zhi Jun Sun, Hai Xia Li, Zhan Xu Tie, and Li Jun Zhao
- Subjects
Pressure drop ,Materials science ,Waste management ,Particle (ecology) ,General Medicine ,Mechanics ,law.invention ,Volumetric flow rate ,Vacuum ceramic filter ,Filter press ,law ,Filter (video) ,visual_art ,visual_art.visual_art_medium ,Ceramic ,Filtration - Abstract
The application of rigid ceramic filter for gas filtration on an industrial scale has shown unstable operation over periods of days. The behavior of the ceramic filtration in further application can be predict by measuring properties of a variety of dust and filtration operation condition. The aim of the experimental investigation is to analysis the pressure distribution inside and outside the ceramic filter along the filter length, and to analyze the pressure drop across the filter along the filter length. Ceramic filter filtration system composes multi-pipe filters for gas clean up is introduced. The operation parameters can be measured by this test system, such as the pressure in the filter cavity and outside the filter surface, velocity outside the filter, gas temperature and humidity, flow rate, dust particle size concentration before gad entering the filter tank and after the gas leaving the filer tank, the pulse cleaning pressure.
- Published
- 2010
4. Simulation Study on Magnetic Field Characteristics of High Magnetic Field Intensity Permanent Magnet Magnetic Filter
- Author
-
Hong Guang Jiao, Peng Liu, and Zhan Xu Tie
- Subjects
Materials science ,Pole piece ,Electromagnet ,Magnetic energy ,Electropermanent magnet ,business.industry ,Force between magnets ,General Engineering ,Electrical engineering ,law.invention ,Magnetic circuit ,Optics ,law ,Magnet ,business ,Magnetic reactance - Abstract
To solve the conflict between separation space and magnetic field intensity, an original magnetic circuit structure system of permanent magnet magnetic filter is designed by utilizing multi-dimensional magnet extrusion technologies, with multi-block NdFeB magnets of different structures and magnetization directions. The inside diameter of the ring magnets and ring soft iron is taken as separating space. To inspect the distribution of the magnetic field characteristics of magnetic circuit system, mathematical model is established, and the designed magnetic circuit system is simulated, taking advantage of the electromagnetic software Magnet. The simulation results show that a larger separating space and higher background magnetic density can be achieved simultaneously by means of the organic magnetic circuit system design, when the thickness of ring soft iron is 4mm and the diameter ratio (outside diameter to the diameter) of ring magnets is 10/3. The highest magnetic induction intensity of 29.2 mm separating space is 1.5T, which provides the basis for permanent magnet magnetic circuit design.
- Published
- 2010
5. Fabrication and gain performance of Er3+/Yb3+-codoped tellurite glass fiber
- Author
-
Xu Tie-Feng, Xiang Shen, Qiuhua Nie, Xunsi Wang, and Shixun Dai
- Subjects
Materials science ,Optical fiber ,Laser diode ,business.industry ,Glass fiber ,chemistry.chemical_element ,General Chemistry ,Noise figure ,Cladding (fiber optics) ,Graded-index fiber ,law.invention ,Erbium ,Optics ,chemistry ,Geochemistry and Petrology ,law ,business ,Refractive index - Abstract
Er3+/Yb3+-codoped TeO2 -ZnO-BaO-La2O3 tellurite glass fiber was fabricated by rotation and rod-in-tube technologies. The thermal stability and optical refractive index of the core and cladding glasses were determined by DTA and optical coupler, respectively. The average background loss of tellurite glass fiber was 1.8 dB/m at 1310 nm. Optical microscopy and field emission scanning electron microscope (FESEM) were used to study structural characteristics of preforms and optical fibers. The main loss of tellurite glass fiber could be attributed to scatter centre due to core-cladding interface defects. The amplifier performance of tellurite glass fiber was investigated by pumping with 980 nm laser diode (LD). The gain coefficient and maximum signal gain were 0.21 dB/mW and 10 dB, respectively, for a pumping power of 120 mW. Gains exceeding 5 dB were obtained over 30 nm bandwidth from 1535 to 1565 nm. The minimum noise figure was 4.8 dB at 1557 nm.
- Published
- 2008
6. Wear fault diagnosis of an emulsion pump crank bearing
- Author
-
Chang-long Du, Zhan-xu Tie, Yong-zhong Zhang, and Xiao-ming Han
- Subjects
Crank ,Bearing (mechanical) ,Materials science ,Mechanical Engineering ,media_common.quotation_subject ,Nuclear Theory ,Energy Engineering and Power Technology ,Mechanical engineering ,Fluid bearing ,Mechanics ,Geotechnical Engineering and Engineering Geology ,Reynolds equation ,law.invention ,Fuel Technology ,law ,Boundary value problem ,Connecting rod ,Eccentricity (behavior) ,Crankpin ,Engineering (miscellaneous) ,media_common - Abstract
The total load on a crank bearing was calculated by performing a load analysis of the crank connecting rod mechanism. The Reynolds equation for hydrodynamic lubrication of the crank bearing was established at the Reynolds boundary condition and was then solved using the Holland method. From this the regular track of the bearing axis was obtained. As the crank bearing gradually wears the eccentricity ratio corresponding to the minimum oil film thickness increases gradually. The oil-bound film eventually breaks down, which allows friction and collision between the metal surfaces of the crank pin and the bearing. The rigid impact leads to excitation of high frequency vibrations at the natural frequencies of the connecting rod. The experiments show that the wear condition of the crank bearing can be identified correctly through the vibration signature at the natural frequencies of the connecting rod. The degree of wear can be predicted accurately through the energy content of the high frequency bands.
- Published
- 2008
7. Optical Field Measurement of Nano-Apertures with a Scanning Near-Field Optical Microscope
- Author
-
XU Ji-Ying, Tian Qian, XU Tie-Jun, and Wang Jia
- Subjects
Materials science ,business.industry ,Aperture ,Near-field optics ,Astrophysics::Instrumentation and Methods for Astrophysics ,General Physics and Astronomy ,Substrate (electronics) ,Optical field ,Focused ion beam ,law.invention ,Light intensity ,Optics ,Optical microscope ,law ,Nano ,Physics::Accelerator Physics ,Optoelectronics ,business - Abstract
We investigate optical near-field distributions of the unconventional C-apertures and the conventional square apertures in preliminary experiment with an aperture scanning near-field optical microscope. These nano-apertures are fabricated in Au film on a glass substrate with focused ion beam technology. The experimental results indicate the uptrend of output light intensity that a C-aperture enables the intensity maximum to increase at least 10 times more than a square aperture with same unit length. The measured near-field light spot sizes of C-aperture and square aperture with 200-nm unit length are 439 nm × 500 nm and 245 nm × 216 nm, respectively.
- Published
- 2004
8. Direct Measurement of Evanescent Wave Interference with a Scanning Near-field Optical Microscope
- Author
-
Hong Tao, Sun Li-Qun, Wang Jia, and XU Tie-Jun
- Subjects
Conventional transmission electron microscope ,Scanning Hall probe microscope ,Atomic de Broglie microscope ,Materials science ,Microscope ,Total internal reflection fluorescence microscope ,business.industry ,Physics::Optics ,General Physics and Astronomy ,law.invention ,Scanning probe microscopy ,Optics ,Optical microscope ,law ,Near-field scanning optical microscope ,business - Abstract
Evanescent wave interference is studied theoretically and experimentally. The interference patterns were directly measured with a scanning near-field optical microscope. The acquired image of the interference pattern is clear and has better contrast than that previously acquired with a photon-scanning tunnelling microscope or laser-trapped particles. The spatial period of the interference fringes is 180 nm, which agrees with the theoretical value. The results indicate that the probe of the scanning near-field optical microscope has a resolution beyond 100 nm. The relation between the evanescent field intensity and the distance is also measured. When the separation between the probe and the interface is up to 180 nm, the intensity can decrease to 1/e of the maximum.
- Published
- 2004
9. Notice of Retraction The research of on-line monitoring methods of capacitive equipments
- Author
-
Quan Yu-sheng, Jiang Huai, Xu Tie-ying, and Jiang Shan
- Subjects
Engineering ,business.industry ,Capacitive sensing ,Electrical engineering ,High voltage ,Hardware_PERFORMANCEANDRELIABILITY ,Signal ,Line (electrical engineering) ,law.invention ,Electric power system ,Capacitor ,Sampling (signal processing) ,Hardware_GENERAL ,law ,Hardware_INTEGRATEDCIRCUITS ,Electronic engineering ,Equivalent circuit ,business - Abstract
In power systems, there are 40% to 50% capacitor-type devices in it. Capacitor performance has a direct relationship to the normal operation of the grid. This article describes several common power system equipments of high voltage capacitor structures and its equivalent circuits. Analyze the current capacitive dielectric loss online monitoring equipment of various methods and principles. And do a detailed comparison of various methods; introduce the advantages and disadvantages of these methods. Summarize several other current on-line monitoring methods. Then point out the sampling signal location of the capacitor-type devices.
- Published
- 2011
10. The near- and mid-infrared emission properties of Tm3+-doped GeGaS-CsI chalcogenide glasses
- Author
-
Zhang Xianghua, Zhang Pengjun(张鹏君), Dai Shixun, Peng Bo(彭波), Xunsi Wang, Xu Tie-Feng, Nie Qiuhua, NINGBO UNIVERSITY, Ningbo University (NBU), Key Lab Transient Opt & Photon, Chinese academy sciences, Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Chalcogenide glasses ,Infrared ,Chalcogenide ,Rare earth ions ,Analytical chemistry ,02 engineering and technology ,01 natural sciences ,law.invention ,010309 optics ,chemistry.chemical_compound ,Optics ,law ,0103 physical sciences ,Materials Chemistry ,Radiative transfer ,Mid-infrared ,Thulium ions ,Quenching (fluorescence) ,business.industry ,Chemistry ,Doping ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Laser ,Fluorescence ,Electronic, Optical and Magnetic Materials ,Ceramics and Composites ,0210 nano-technology ,business ,Luminescence - Abstract
Serials of chalcogenide glasses based on composition of 72GeS(2)-18Ga(2)S(3)-10CsI (in mol%) and doped with high Tm3+ content (up to 10,000 ppm) were prepared, and their luminescence properties were investigated under excitation with 800 nm laser. The influences of doping concentration on Judd-Ofelt intensity parameter Omega(i) spontaneous transition probability A, fluorescence branching ratio beta, and radiative lifetime tau(rad) of Tm3+ in the samples were studied. Four infrared emission bands observed were centered at 1.48, 1.8, 2.3, and 3.8 mu m, corresponding to optical transitions H-3(4) -> F-3(4), F-3(4) -> H-3(6), H-3(4) -> H-3(5) and H-3(5) -> F-3(4), respectively. For 1.0 wt.% Tm3+: doped sample, no concentration quenching was observed and its emission cross-sections at 2.3 and 3.8 mu m calculated by using Fuchtbauer-Ladenburg equation were 6.85 x 10(-21) and 7.66 x 10(-21) cm(-2), respectively. (C) 2010 Elsevier B.V. All rights reserved.
- Published
- 2010
11. Investigation of spectral properties and thermal stability of Er3+/Yb3+ co-doped TeO2-B2O3-SiO2 glasses
- Author
-
Dai Shi-Xun, Zhang Xianghua, Shen Xiang, Xu Tie-Feng, Lu Long-Jun, Zhang Xu-Dong, Nie Qiuhua, NINGBO UNIVERSITY, Ningbo University (NBU), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
- Subjects
Materials science ,Infrared ,Analytical chemistry ,General Physics and Astronomy ,[CHIM.MATE]Chemical Sciences/Material chemistry ,Spectral line ,law.invention ,Ion ,Full width at half maximum ,law ,Thermal stability ,Emission spectrum ,Crystallization ,Glass transition ,ComputingMilieux_MISCELLANEOUS - Abstract
A series of Er 3+ /Yb 3+ co-doped (85- x ) TeO 2 -15B 2 O 3 - x SiO 2 (TBS x =0,5,10,15,20 mol%) glasses have been prepared. The thermal stability, absorption and emission spectra, lifetime of Er 3+ : 4 I 13/2 level and infrared transmit spectra were measured and discussed. The emission spectra of Er 3+ : 4 I 13/2 → 4 I 15/2 transition was analyzed using a peak-fit routine, and an equivalent four-level system was proposed to estimate the Stark splitting for the 4 I 15/2 and 4 I 13/2 levels of Er 3+ ions. It was found that the thermal stability of these glasses was improved by introducing SiO 2 . The difference between the glass transition temperature ( T g ) and the crystallization onset temperature ( T x ), Δ T = T x - T g , have came to 178℃ when SiO 2 was 20 mol%, indicating that they were suitable for fiber drawing. The fluorescence full width at half maximum (FWHM) and peak of emission cross-section ( σ peak e ) of Er 3+ ions in different glass hosts have been compared. The results indicate that these new TBS glasses are promising host material for broadband amplifiers.TeO 2 -B 2 O 3 -SiO 2 , thermal stability, G
- Published
- 2007
12. Fiber Bragg grating interrogating system employing an arrayed waveguide grating
- Author
-
Zhou Qinfeng and Xu Tie-Feng
- Subjects
PHOSFOS ,Materials science ,Holographic grating ,business.industry ,Physics::Optics ,Long-period fiber grating ,Arrayed waveguide grating ,law.invention ,Ultrasonic grating ,Wavelength ,Optics ,Fiber Bragg grating ,law ,Blazed grating ,business - Abstract
Two types of interrogating schemes based on an waveguide grating for fiber Bragg grating sensors are reviewed. A method of extending the wavelength measuring range is proposed. And experiment results match well with the theory.
- Published
- 2007
13. On the enhancement of superconductivity due to Van Hove singularity
- Author
-
Bai Gui-ru and Xu Tie-Feng
- Subjects
Physics ,Superconductivity ,High-temperature superconductivity ,Condensed matter physics ,Band gap ,Van Hove singularity ,BCS theory ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,law.invention ,law ,Condensed Matter::Superconductivity ,Quantum mechanics ,Density of states ,General Materials Science - Abstract
We have rigorously solved the standard BCS gap equation with the density of states of Van Hove type. The result shows that the enhancement ofTc is not as effective as previously estimated. It seems unlikely that Van Hove singularity inN(E) can be theTc-enhancement mechanism for the high-Tc Cu oxides.
- Published
- 1992
14. Model of quench cooling and experimental analysis of cylindrical infrared chalcogenide glass
- Author
-
Song Bao-An, Dai Shixun, Xu Tie-Feng, Shen Xiang, Lin Chang-Gui, Wang Xunsi, and Nie Qiuhua
- Subjects
Range (particle radiation) ,Materials science ,Infrared ,business.industry ,General Physics and Astronomy ,Chalcogenide glass ,Edge (geometry) ,Condensed Matter::Disordered Systems and Neural Networks ,law.invention ,Surface heat ,Optics ,law ,Transmittance ,Composite material ,Crystallization ,Glass transition ,business - Abstract
The tapping temperature and the cooling rate are the key parameters during the development process of chalcogenide glass. Based on the theory of heat conduction equation, a model for calculating the temperature distribution of cylindrical chalcogenide glass is established using the least square fitting method in this paper. The tapping temperature, the temperature distribution and the cooling rate are simulated by using the model. The simulation results are compared with experimental data. The results show that the glass temperature stays in a non-steady non-uniform distribution, the surface cooling is the fastest, and the temperature decreases exponentially with time when the glass is tapped off from the furnace; the temperature of glass rod from the center to the edge is approximately of parabola distribution; the crystallization is the most difficult when the glass is tapped off at 50100 ℃ higher than crystallization temperature and a surface heat exchange coefficient of 180 W m-2K-1. Under the guidance of the theoretical model the uniform and transparent chalcogenide glass with a diameter of 110 mm and height of 80 mm is obtained. The glass transmission spectrum range is 0.817 m. The 2 mm thick flat sheet has the average transmittance higher than 65% in a 812 m range.
- Published
- 2011
15. 2.9 μm luminescence properties of Pr3+/Ho3+ codoped Ge-Ga-Se glasses
- Author
-
Nie Qiuhua, Dai Shi-Xun, Shen Xiang, Wang Xunsi, Xu Tie-Feng, and Zhu Jun(朱军)
- Subjects
Materials science ,Absorption spectroscopy ,business.industry ,Chalcogenide ,Analytical chemistry ,Absorption cross section ,General Physics and Astronomy ,Laser ,Fluorescence ,Ion ,law.invention ,chemistry.chemical_compound ,Optics ,chemistry ,law ,Luminescence ,business ,Excitation - Abstract
A series of chalcogenide glasses based on Ge 25 Ga 10 Se 65 system co-doped with Ho 3+ /Pr 3+ ions of different ratios were synthesized by melt-quenching technique. The absorption spectra,mid-infrared fluorescence and lifetime of glass samples under 908 nm laser excitation were measured. The emission cross section of Ho 3+ : 5 I 7 → 5 I 8 and absorption cross section of Pr 3+ : 3 H 4 → 3 F 2 were calculated. The energy transfer efficiency between Ho 3+ and Pr 3+ ions with different Pr 3+ ion concentrations have been discussed. Through fitting the 2.0 μm fluorescence decay curves of Ho 3+ ions,the energy transfer regime was judged. The results prove thatTm 3+ is an efficient sensitizer which enhances the Ho 3+ : 2.9 μm fluorescence intensity significantly.
- Published
- 2010
16. Investigation of spectral properties and thermal stability of Er3+/Yb3+ co-doped tungsten-tellurite glasses
- Author
-
Shen Xiang, Xu Tie-Feng, Nie Qiuhua, and Gao Yuan
- Subjects
Materials science ,Spectral properties ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Mineralogy ,Tungsten ,law.invention ,Ion ,Full width at half maximum ,chemistry ,law ,Thermal stability ,Emission spectrum ,Crystallization ,Absorption (chemistry) - Abstract
Er 3+ /Yb 3+ co-doped tungsten-tellurite glasses, 65TeO 2 -25WO 3 -10R m O n (R m O n = PbO,BaO), (65+x) TeO 2 -(25-x)WO 3 - 10La 2 O 3 (x=0,5,10),(60+x)TeO 2 -(30-x)WO 3 -10Bi 2 O 3 (x=0,5,10) have been prepared. The thermal stability and spectral properties, such as absorption spec tra, emission spectra and lifetimes of the 4 I 13/2 level of Er 3+ were investigated. Results obtained show that tungsten-telluri te glasses have good thermal stability. All the glass samples except the Bi 2 O 3 -containing g lasses show no onset temperature of crystallization (T x ), indicating that they are stable for fiber drawing. Three intensity parameters Ω t (t= 2,4, 6) were calculated by Judd-Ofelt theory. It is shown that Ω 2 is domi nated b y the covalency between the Er 3+ and O 2- , the effect of as ymmetry in the local structures around the Er 3+ ions on Ω 2 can be neglected. The full width at half maximum (FWHM=71—77 nm) of the 4 I 13/2 → 4 I 15/2 emission and lifetimes of 4 I 13/2 level(τ m = 3—3.4 ms) of Er 3+ ions were measured. The emission cross-section ( σ peak =068—103×10 -20 cm 2 ) of the 4 I 13/2 → 4 I 15/2 transitio n of Er 3+ ions were calculated according to the McCum ber the ory. The FWHM and emission cross-section of Er 3+ ions at 1.5 μm ba nd in d ifferent glass hosts were compared. The results show that tungsten-tellurite gla ss will be the promising host material for 1.5 μm broadband amplification.
- Published
- 2005
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.