Li C.,Beihang University |
Zeng Z.,Beihang University |
He X.,China Nonferrous Metal Guilin Geology and Mining Co.
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering
A novel optical sensor for simultaneous measurement of voltage and current is proposed and demonstrated in experiment. The optical sensing unit is only composed of single bismuth silicate (Bi12SiO20, BSO) crystal and two prism polarizers. The BSO crystal exhibits both Pockels electrooptic effect and Faraday magnetooptic effect, thus voltage and current to be measured can simultaneously modulate the probing light wave when transparent axes of the two polarizers are parallel or perpendicular with each other. The frequency of current sensing signal is the same as that of the original current to be measured, meanwhile, that of voltage sensing signal is doubled. Thus current and voltage sensing signals can be simultaneously separated and measured by using two band pass filters. AC current and voltage with industrial frequency in the ranges of 6 A and 200 V were simultaneously measured in experiment by use of single BSO crystal with a size of 6.0×4.0×2.9 mm3. Source
Liu Y.,China Nonferrous Metal Guilin Geology and Mining Co. |
Zhou Y.,Guangdong University of Technology |
Zhang F.,Guangdong University of Technology |
Guo C.,Guangdong University of Technology
Jingangshi yu Moliao Moju Gongcheng/Diamond and Abrasives Engineering
Diamond dental tools with diamond particles of 251 μm and 107 μm were fabricated by brazing separately, and used to grind zirconia ceramic. The effect of feed rate and spindle speed on grinding force and the comparison between the diamond tools were studied. Results showed that with the increase of feed rate and spindle speed, the normal grinding force and tangential grinding force increased linearly. The grinding force of brazed dental tool with particle size of 107 μm was less than that of brazed dental tool with particle size of 251 μm. As feed rate increased, brittle fracture expanded to a larger area on the surface of processed zirconia ceramic and chip size increased with a trend of bigger forms. As spindle speed increased, apparent plastic deformations appeared on the surface of processed zirconia ceramic with thinning chips. ©, 2015, Zhengzhou Institute of Abrasives Grinding. All right reserved. Source
Li C.-S.,Beihang University |
Zeng Z.,Beihang University |
He X.-L.,China Nonferrous Metal Guilin Geology and Mining Co.
Guangdianzi Jiguang/Journal of Optoelectronics Laser
An optical voltage sensor is proposed which uses one single bismuth silicate (Bi12SiO20, BSO) crystal grown by hydrothermal method. The voltage sensing unit is only composed of one block of BSO crystal and two prism polarizers. Experimental results demonstrate that the used BSO crystal sample exhibits obvious linear electro-optic Pockels effect, and can be used for the measurement of alternating voltage. By use of the inherent natural optical activity in the BSO crystal, monotonous and linear voltage measurement ranges of the proposed voltage sensor are larger than those of the conventional voltage sensors using electro-optic crystals without optical activity. The size of the used BSO crystal sample is 6.0 mm×4.0 mm×2.9 mm3. The angle, through which the plane-of-vibration rotates in the BSO crystal due to its optical activity, is about 132° for light wavelength of 633 nm. The measurand voltage is the alternating voltage with industrial frequency of 50 Hz, and is monotonously and nonlinearly measured in the range of 108-1 300 V (root-mean-square amplitude). The output voltage of the sensor is still monotonously changed with measured voltage when the corresponding electro-optic phase retardation reaches 2π. In addition, under the application of a proper stress-induced birefringence in the BSO crystal, the output voltage is linearly changed with measured voltage in a certain voltage range, e. g., 900 V, corresponding voltage measurement sensitivity is 0.027 6 mV/V and nonlinear error is less than 3.1%. Source
Cheng F.,Central South University |
Cheng F.,China Nonferrous Metal Guilin Geology and Mining Co. |
Wang X.-H.,Central South University |
Mo S.-X.,China Nonferrous Metal Guilin Geology and Mining Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering
Based on the acid-base proton theory, the erosion mechanism after heavy metal pollutants infiltrating into rock is discussed. The extension performances of lead (Pb), cadmium (Cd), copper (Cu), zinc (Zn) are analyzed by using the convection-diffusion model. By way of combining the viscoelastic model and the damage monomer model, a 3D extended-fissile model is established for heavy metal contaminated rock. The deformation rules of invaded surface are discussed under different extension rates. The model fitting results are verified by the data of axial static load tests. The results show that different heavy metal pollutants have different invasion and extension performances in rock, and there is a good agreement between the experimental stress-strain curves of contaminated rock with different lithologies in the same test conditions and the fitting results of the combination model. Source
Xu T.,CAS Technical Institute of Physics and Chemistry |
Xu T.,University of Chinese Academy of Sciences |
Liu L.,CAS Technical Institute of Physics and Chemistry |
Wang X.,CAS Technical Institute of Physics and Chemistry |
And 4 more authors.
Journal of Alloys and Compounds
Deep-UV nonlinear optical crystal RbBe2BO3F2 (RBBF) grown by the hydrothermal method was found to have a centrosymmetric structure of R3¯c by powder X-ray diffraction. The structure of R3¯c has cell parameters of a = 4.44223(11) Å and c = 39.6696(12) Å in the lattice where the (BO3)3 - groups turn 60° along each (Be2BO3F2)∞ layer in the a-b plane and it is double size along the c-axis compared with standard R32 structure. As the examined RBBF shows a very low second harmonic generation capability, a stacking fault model was proposed that the hydrothermal RBBF is nonuniform with a mixture of both R32 and R3¯c structures using the DIFFaX program. © 2014 Elsevier B.V. All rights reserved. Source