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41 results on '"Wang, Guoju"'

17. Strata-pressure behavior of double-unit mining method combining fully-mechanized and mechanized coal face

Author

Xu Yanfei, Wang Guoju, and Fu-jun Zhao

Subjects
Engineering, business.industry, Abutment, Coal mining, Energy Engineering and Power Technology, Geotechnical Engineering and Engineering Geology, symbols.namesake, Superposition principle, Mining engineering, Face (geometry), Gaussian function, symbols, Point (geometry), Geotechnical engineering, business, Roof, Stress concentration
Abstract

Based on the engineering background of double-unit face mining under complicated geological conditions and the lagging fully-mechanized face surpassing the fore mechanized face of double-unit face in Zhou Yuanshan coal mine, strata-pressure behavior in the process was analyzed based on FLAC3D and on-site measurement. The results show that the stress concentration factor of superposition abutment pressure and the alternate distance of double-unit face are meeting gauss function, the relationship between the depth of stress concentration point and alternate distance also meets gaussian function. When the alternate distance is larger than 24 m, the superimposition of pilot support pressure in the double-unit face is weak. When the alternate distance is more than 12–15 m, the changes of the roof subsidence coefficient and the depth of stress concentration point are stabilized; when the alternate distance is 3–6 m, the fore working face end is in the greatest impact area of superposition abutment pressure, this area should be avoided in determining the reasonable alternate distance.

Published
2013

22. Dual-wavelength self-Q-switched Nd:GYSGG laser

Author

Song, Qi, primary, Wang, Guoju, additional, Zhang, Bingyuan, additional, Zhang, Qingli, additional, Wang, Wenjun, additional, Wang, Minghong, additional, Sun, Guihua, additional, Bo, Yong, additional, and Peng, Qinjun, additional

Published
2015
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35. Impact of environmental conditions on the sorption behavior of radionuclide Ni(II) onto hierarchically structured γ-MnO.

Author

Mou, Juan, Wang, Guoju, Shi, Wenxian, and Zhang, Shouwei

Subjects
SORPTION, NICKEL isotopes, NICKEL compounds, MANGANESE oxides, CHEMICAL structure, ENVIRONMENTAL impact analysis, CHEMICAL reactions
Abstract

A novel hierarchically structured γ-MnO has been synthesized using a simple chemical reaction between MnSO and KMnO in aqueous solution without using any templates, surfactants, catalysts, calcination and hydrothermal processes. As an example of potential applications, hierarchically structured γ-MnO was used as adsorbent in radionuclide Ni(II) treatment, and showed an excellent ability. The effects of pH, ionic strength, temperature, humic acid (HA) and fulvic acid (FA) on the sorption of radionuclide Ni(II) to hierarchically structured γ-MnO have been investigated by using batch techniques. The results indicated that the sorption of Ni(II) on γ-MnO is obviously dependent on pH values but independent of ionic strength. The presence of HA/FA strongly enhances the sorption of Ni(II) on γ-MnO at low pH values, whereas reduces Ni(II) sorption at high pH values. The sorption of Ni(II) on γ-MnO is attributed to inner-sphere surface complexation rather than outer-sphere surface complexation or ion exchange. The thermodynamic parameters (Δ H, Δ S, Δ G) are also calculated from the temperature dependent sorption isotherms, and the results suggest that the sorption of Ni(II) on γ-MnO is a spontaneous and endothermic process. [ABSTRACT FROM AUTHOR]

Published
2012
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36. Improvment crystallinity of SiC films by addition of CF4 in HFCVD

Author

Wang, Guoju, Wang, Bo, Huang, Anping, Zhu, Mankang, Yu, Munan, and Yan, Hui

Subjects
*CRYSTALS, *X-ray diffraction, *ATOMIC force microscopy, *SCANNING probe microscopy
Abstract

With CF4 addition, crystalline 3C–SiC films were synthesized at a low substrate temperature of 480°C by hot filament chemical vapor deposition with CH4–SiH4–H2 gas mixture. It was observed that the full-width at half-maximum of both vibration peaks of Si–C bonds in Fourier transform infrared spectra and 3C–SiC (1 1 1) peaks in X-ray diffraction patterns decreased evidently as the flux of CF4 increased. The results imply that the crystallinity of the films can be improved by adding CF4. Moreover, the micrographs of atomic force microscopy showed that the surface of the SiC films became rougher with the flux of CF4 increasing, which is resulted from the larger grains of the SiC films. [Copyright &y& Elsevier]

Published
2004
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38. Comparative studies of semiconductor saturable absorber mirror mode-locking dynamics in pulsed diode-end-pumped picosecond Nd:GdVO4 and Nd:YAG lasers

Author

Zhang, Bingyuan, Li, Gang, Chen, Meng, Wang, Guoju, and Wang, Yonggang

Abstract

Ultrashort pulses were generated in passively mode-locked Nd:YAG and Nd:GdVO4 lasers pumped by a pulsed laser diode with 10-Hz repetition rate. Stable mode-locked pulse trains were produced with the pulse width of 10 ps. The evolution of the mode-locked pulse was observed in the experiment and was discussed in detail. Comparing the pulse evolutions of Nd:YAG and Nd:GdVO4 lasers, we found that the buildup time of the steady-state mode-locking with semiconductor saturable absorber mirrors (SESAMs) was relevant to the upper-state lifetime and the emission cross-section of the gain medium.

Published
2006

39. Flash-lamp-pumped picosecond Nd:YAG regenerative amplifier

Author

Zhang, Bingyuan, Li, Gang, Chen, Meng, Wang, Guoju Wang2; Yonggang, and Ma, Xiaoyu

Abstract

A flash-lamp-pumped Nd:YAG regenerative amplifier has been developed at 1.06 ?m, seeded with 10-ps pulses from a diode-end-pumped and mode-locked Nd:YAG oscillator with homemade semiconductor saturable absorber mirror (SESAM). The pulse energy was amplified to 2 mJ by the regenerative amplifier at 10-Hz repetition rate. In two-stages amplifier the regenerative amplified pulse energy was amplified to 100 mJ, and 35-mJ double frequency at 532 nm was obtained by extra-cavity double frequency with a KTP crystal.

Published
2005

40. Passively Q-switched Nd:GdVO4 laser with In0.25Ga0.75As being an output coupler

Author

Zhang, Bingyuan, Li, Gang, Chen, Meng, Wang, Guoju, and Wang, Yonggang

Subjects
*DIODES, *LASERS, *VACUUM tubes, *LIGHT amplifiers
Abstract

Abstract: We report a diode-end-pumped passively Q-switched Nd:GdVO4 laser operating at 1.06μm with In0.25Ga0.75As being the saturable absorber as well as an output coupler. Q-switched pulses with a pulse duration of 20ns, pulse energy 4.2μJ and pulse repetition rate 200kHz were produced, corresponding to peak power of 210W. [Copyright &y& Elsevier]

Published
2007
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