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1

Defect solitons supported by kagome photonic lattices in biased photovoltaic-photorefractive crystals

Hui J., Lu K., Zhao C., Gao L., Chen W.

Optica Applicata

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2018

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Vol. 48, nr 3

349--359

EN

We report that defect solitons can be supported by kagome photonic lattices with a defect in biased photovoltaic-photorefractive crystals. For a positive defect, these defect solitons exist only in the semi-infinite bandgap and are stable in the low power region but unstable in the high power region. For a negative defect, these defect solitons exist in both of the semi-infinite bandgaps and the first bandgap. In the semi-infinite bandgap, low-power defect solitons are stable when the negative defect depth is low and unstable when the negative defect depth is high, moderate-power defect solitons are stable when the negative defect depth is high, and high-power defect solitons are unstable for all the negative defect depths. In the first bandgap, defect solitons are stable in all the power regions when the negative defect depth is low. When the negative defect depth is high, defect solitons are stable in the high power region and unstable in the low power region. On the other hand, these defect solitons are those studied previously in kagome photonic lattices with a defect in biased non-photovoltaic-photorefractive crystals when the bulk photovoltaic effect is negligible and those in kagome photonic lattices with a defect in photovoltaic-photorefractive crystals when the external bias field is absent.

2

Mechanism and Kinetics Studies on Non-Isothermal Decomposition of Ludwigite in Inert Atmosphere

Fu X., Chu M., Gao L., Liu Z.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 3

1217--1224

EN

Ludwigite is the main available boron-bearing resource in China. In order to enrich the theory system and optimize its utilization processes, this paper study the mechanism and kinetics on non-isothermal decomposition of ludwigite in inert atmosphere by means of thermal analysis. Results show that, the decomposition of serpentine and szajbelyite is the main cause of mass loss in the process. At the end of decomposition, hortonolite and ludwigite are the two main phases in the sample. The average E value of structural water decomposition is 277.97 kJ/mol based on FWO method (277.17 kJ/mol based on KAS method). The results is proved to be accurate and reliable. The mechanism model function of structural water decomposition is confirmed by Satava method and Popescu method. The form of the most probable model function is G(α) = (1 – α)–1– 1 (integral form) and f (α) = (1 – α)2 (differential form), and its mechanism is chemical reaction. This is verified by the criterion based on activation energy of model-free kinetics analysis.

3

Electrorefining of High Carbon Ferromanganese in Molten Salts to Produce Pure Ferromanganese

Xiao S.J., Liu W., Gao L., Zhang J.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 3

1505--1509

EN

High carbon ferromanganese is used as a starting material to prepare pure ferromanganese by electrorefining in molten salts. High carbon ferromanganese was applied as the anode, molybdenum was the cathode and Ag/AgCl was the reference electrode. The anodic dissolution was investigated by linear polarization in molten NaCl-KCl system. Then potentiostatic electrolysis was carried out to produce pure ferromanganese from high carbon ferromanganese. The cathodic product was determined to be a mixture of manganese and iron by x-ray diffraction (XRD). The content of carbon in the product was analyzed by carbon and sulfur analyzer. The post-electrolysis anode was characterized by scanning electron microscope (SEM). The mechanism of the anode dissolution and the distribution of the main impurity of carbon and silicon after electrolysis were discussed.

4

Numerical Study of the Effect of Furrows on Biosonar Beamforming in Aselliscus Stoliczkanus Bat

He W., Feng J., Gao L., Zhang Z., Lu H.

Archives of Acoustics

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2017

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Vol. 42, No. 3

395--399

EN

The Aselliscus Stoliczkanus bat, studied here, has intricately shaped structures surrounding the nostrils. These structures are hypothesised to have influence on animals’ acoustic radiation patterns. Using micro-tomography scanning technique, a 3D digital model of the noseleaf is reconstructed and biosonar beam pattern is analysed using a finite element method based on the 3D noseleaf model. The present research focuses on the conspicuous furrows in noseleaf, and our analysis allows to conclude the followings: a) structural details in noseleaf of Aselliscus Stoliczkanus bat can produce acoustic effects even if it is not adjacent to the nostrils, b) the furrows possess frequency-selective characteristics, c) the furrows have the function to manipulate the direction and width of the outgoing ultrasound wave.

5

Removal of quinoline from aqueous solutions by lignite, coking coal and anthracite. Adsorption isotherms and thermodynamics

Xu H., Huagn G., Li X., Gao L., Wang Y.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 1

214--227

EN

Based on the concept of circular economy, a novel method of industrial organic wastewater treatment by using adsorption on coal is introduced. Coal is used to adsorb organic pollutants from coking wastewaters. After adsorption, the coal would be used for its original purpose, its value is not reduced and the pollutant is thus recycled. Through systemic circulation of coking wastewater zero emissions can be achieved. Lignite, coking coal and anthracite were used as adsorbents in batch experiments. The quinoline removal efficiency of coal adsorption was investigated. The coking coal and anthracite exhibited properties well-suited for adsorption onto both adsorbents. The experimental data were fitted to Langmuir and Freundlich isotherms as well as Temkin, Redlich–Peterson (R-P) and Dubinin-Radushkevich (D-R) models. Both Freundlich Isotherm and D-R model provided reasonable models of the adsorption process. The thermodynamic parameters of quinoline adsorption on coking coal were calculated. The thermodynamic parameters indicated that the adsorption process is exothermic and is a physical adsorption. The △S° value indicated that the adsorption entropy decreased because the adsorbate molecule was under restrictions after it adsorption on the coal surface. The coal adsorption method for removing refractory organic pollutants is a great hope for achieving zero emission waste water for a coking plant.

6

Removal of quinoline from aqueous solutions by lignite, coking coal and anthracite. Adsorption kinetics

Xu H., Wang Y., Huagn G., Fan G., Gao L., Li X.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 1

397--408

EN

Basing on the concept of circular economy, a novel method of industrial organic wastewater treatment by using adsorption on coal is introduced. Coal is used to adsorb organic pollutants from coking wastewaters. After adsorption, the coal would be used in its original purpose, as its value was not reduced and the pollutant was reused. Through the systemic circulation of coking wastewater zero emissions can be achieved. Lignite, coking coal and anthracite were used as adsorbents in batch experiments. The quinoline removal efficiency of coal adsorption was investigated. Both the coking coal and anthracite exhibited properties well-suited for quinoline adsorption removal. The experimental data were fitted to the pseudo-first- order and pseudo-second-order kinetic equations as well as intraparticle diffusion and Bangham models. An attempt was made to find the rate-limiting step involved in the adsorption processes. Both boundary-layer diffusion and intraparticle diffusion are likely involved in the rate-limiting mechanisms. Effect of pH on coal adsorptions by coking coal was investigated. The process of quinoline adsorption on coal was researched. The coal adsorption method for removing refractory organic pollutants is a great hope for achieving wastewater zero emission for coking plants.

7

Pretreatment of coking wastewater by an adsorption process using fine coking coal

Gao L., Li S., Wang Y., Gui X., Xu H.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 1

422--436

EN

A new technique for pretreatment of coking wastewater is introduced based on the concept of circular economy. Coal is fed into a coking system after adsorption. This study validates the feasibility of using coking coal to adsorb organic pollutants in coking wastewater. The sorption kinetics and equilibrium sorption isotherms of coking coal for removal of chemical oxygen demand (COD) and phenol from coking wastewater was also discussed in this paper. Gas chromatograph/mass spectroscopy (GC/MS) was used to detect changes in the quality of coking wastewater. The results showed that when coking coal dosage was 120 g/dm3, 65% of COD and 34% of phenol in waste water can be removed after 40 min of agitation. The surface functional groups of coking coal before and after adsorption were observed with a Fourier transform infrared spectrometer. The kinetics of COD and phenol adsorption from coking wastewater by coking coal fitted the pseudo second-order model. The adsorption process of coking coal can be classified into two categories, namely, rapid and slow. The Freundlich isotherm provided a better fit with all adsorption isotherms than the Langmuir isotherm. Coking coal could be a suitable low-cost adsorbent for recalcitrant organic pollutants.

8

A distributed soil temperature measurement system with high spatial resolution based on BOTDR

Gao L., Shi B., Zhu Y., Wang K., Sun Y., Tang C.

Optica Applicata

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2011

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Vol. 41, nr 3

607--616

EN

This paper presents a new, recently developed, distributed soil temperature measurement sensor system, with high spatial resolution, based on Brillouin optical time domain reflectometry (BOTDR). The process of developing the distributed soil temperature sensor is introduced in detail, including the principle, materials, installation, instrumentation and calibration. The new distributed soil temperature sensor improves the spatial resolution from 100 cm to 3.3 cm, and has some other unique advantages, including long distance measurement capability, a longer life cycle, galvanic isolation, EMI immunity, good stability and ease of integration. Finally, an in situ comparison test was carried out, where results from the new sensor were compared to data measured using a standard point-mode system. This test proves that the newly developed distributed sensor is both accurate and has the capability to measure continuously the distribution of the soil temperature along the whole borehole depth, indicating that this new measure technique has a wide and powerful application potential.

9

A multimode interference polymer-silica hybrid waveguide 2×2 thermo-optic switch

Sun X. Q., Chen C. M., Wang F., Sun J., Gao W. N., Gao L., Zheng H. L., Kang C. P., Zhang D. M.

Optica Applicata

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2010

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Vol. 40, nr 3

737--745

EN

A polymer-silica hybrid 2×2 thermo-optic switch is demonstrated. The top cladding and core layer are composed of polymers, while the bottom cladding is made of silica. Since polymer and silica have opposite signs of thermo-optic coefficients, the change of the refractive index of the core is opposite to that of the bottom cladding as the temperature increased. With the finite difference beam propagation method (FD-BPM) and thermal coupling simulation, the proposed device presents a crosstalk of 20 and 18 dB at bar state and cross state, respectively. The device also exhibits extinction ratios of 19 and 27 dB at each state. In addition, the low absorption of material and simple structure of the device enable the insertion loss to be 17 dB. Also the electrical power consumption is about 45 mW at ? = 1.55 mm. The rise time and fall time of switching are 0.2 ms and 0.4 ms, respectively.

10

Fibrous composite with threshold strength in three dimensions

Jin X. H., Gao L., Sun J., Gui L. H.

Materiały Ceramiczne

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2010

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T. 62, nr 4

486-489

EN

In the present work, a fibrous composite consisting of square fibers separated with thin compressive layer is designed. Due to the crack arresting effect of the compressive layer, this composite is expected to show three-dimensional threshold strengths corresponding to applied stresses in the direction perpendicular to the fiber side face and parallel to the fiber central axis, respectively. In accordance with the above designing concept, Si3N4/TiN fibrous composites with distinctive threshold strengths were readily prepared through a simple double-laminating procedure. It is found that the threshold strengths increase with the TiN content in the fiber; and for the same material, its axial threshold strength is larger than the radial one. The fundamental reasons for that are investigated.

PL

W prezentowanej pracy zaprojektowano kompozyt włóknisty składający się z włókien o przekroju kwadratowym, rozdzielonych cienką warstwą zawierającą naprężenia ściskające. Z powodu efektu zatrzymywania pęknięcia od kompozytu tego oczekuje się, że pokaże trójwymiarową wytrzymałość progową odpowiadającą zastosowanym naprężeniom w kierunku odpowiednio prostopadłym do powierzchni czołowej włókna i równoległym do jego centralnej osi włókna. Zgodnie z koncepcją projektową bez trudu przygotowano kompozyty włókniste Si3N4/TiN za pomocą prostej procedury podwójnego laminowania. Stwierdza się, że wytrzymałości progowe zwiększają się wraz z zawartością TiN we włóknie, i dla tego samego materiału, jego osiowa wytrzymałość progowa jest większa niż promieniowa. Zbadano zasadnicze powody występowania takiego stanu.

11

Design and fabrication of an organic/inorganic hybrid co-planar waveguide electro-optic modulator

Gao W., Sun J., Sun X., Yan Y., Gao L., Zhang D.

Optica Applicata

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2009

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Vol. 39, nr 3

467-472

EN

We have successfully designed and demonstrated a co-planar waveguide (CPW) Mach-Zehnder (MZ) electro-optic (EO) modulator using a strip-loaded waveguide structure. The hybrid material, easily synthesized by sol-gel process, with a large EO coefficient of r33 = 50 pm/V and a long- -term stability at 80 °C for 200 hours is selected as the active layer. A simple and easily fabricated strip-loaded waveguide structure is designed for utilizing the EO material and reducing the coupling loss with optical fiber. The optimized design principles of the efficient transmission for such a modulator are discussed. The measured half-wave voltage V? of 8.5 V for the MZ modulator is gained at 1550 nm and shows a good agreement with the simulating result.