Advanced Materials Research Vols. 986-987

Abstract: The drying experiments of three typical kinds of Inner Mongolia lignite were conducted on a self-designed apparatus. The proximate analyses and oxygen adsorbing capacities of all the samples were analyzed on an industrial analyzer and a coal spontaneous combustion tendency tester. The results show that the treated samples show no apparent changes in their properties compared to the original lignite and no pyrolysis or combustion phenomenon occurs in the drying process. It is also observed that the oxygen adsorbing capacity of the dewatered sample is lower than that of the original lignite. Especially the oxygen adsorbing capacity of the lignite sample undergoing high-temperature drying process decreases significantly. Considering the amount of adsorbed oxygen can reflect the spontaneous combustion tendency of coal to a certain extent, the spontaneous combustion tendency of the treated lignite decreases.

Abstract: Nowadays, the strained-Si technology has been used to maintain the momentum of semiconductor scaling due to its enhancement performance result from the higher mobility. In this paper, the influence of ionizing impurity scattering, acoustic phonon scattering and intervalley scattering to strained-Si (101) material is discussed.In addition, a calculation of the electron mobility in Strained-Si (101) material is made using the average momentum relaxation time method described in Ref [1]. The results show that the electron mobility increases gradually for both [001] and [100] orientations while for [010] orientation increases rapidly with the increasing Ge fraction x.^[1]

Abstract: Previously researchers considered ions in electric double layers (EDL) to analyze the phenomenon of alternating current electroosmosis (ACEO). However, they did not give a deep interpretation about the formation mechanism of ACEO and their theories cannot explain some experimentally observed phenomena. In this paper, we propose a physical model to analyze the formation mechanism of ACEO by considering ions both in EDL and in solution. It is found that the ions in solution play an important role in ACEO, and by considering the effect of ions both in EDL and in solution, we can reasonably explain some phenomena, including flow reversal at high frequency (typically 10-100 kHz) and inapplicability of ACEO at high salt concentration (above 30 μM), which existing theories cannot give convincing explanations. We also use Navier-Stokes equation to theoretically analyze the ACEO and it is found that the flow reversal can be predicted by our concepts in certain conditions.

Abstract: Viscosity of Watered fuel oil, which was prepared by a self-made mechanical micro-mixing device, was measured with rotation viscosimeter. The effects of oil temperature, agitation speed and water content on viscosity were investigated in this research. The experimental results showed that: viscosity of watered fuel oil decreases with the increasing of oil temperature between 60-80 °C and water contents in 2.0-8.0 %, but increases with the accelerating agitation speed at 1000-1300 r/min.

Abstract: Material balance calculation was adopted to a bubbling desulfurization system of 600MW unit for water-saving measures. Analysis was made on main factors affecting water consumption. Results showed that heat release of desulfurization reaction and water evaporation went up with sulfur content increasing; Free water and bound water in gypsum increased rapidly with calcium improved; When sulfur content enhanced from 0.5% to 3.5%, water evaporation of reactor increased by 28.9% and waste water increased by 7.8%; With inlet flue temperature of WFGD raised from 120°C to 200°C, waste water increased by 25.3% and evaporation of water increased by 102.35%; Once gas-gas heater (GGH) was installed, heat release of original flue gas decreased by 43.72% and the total water consumption decreased by 39.06%. Therefore, with sulfur content and temperature of inlet flue increasing, water consumption raises. Installation of gas-gas heater (GGH) can effectively reduce water consumption of WFGD system.

Abstract: The serials of blue phosphors, CaAl₂Si₂O₈: Eu²⁺ doped with different content Sr²⁺ and Mg²⁺ ions, were prepared by solid-state reaction at high temperature. And their structure and photo-luminescent properties were investigated. In Ca_0.96-ySr_yAl₂Si₂O₈: 0.04Eu²⁺ (y = 0.10, 0.30, 0.50, 0.70, 0.90) system, for y ≦ 0.03, all the compositions crystallize in triclinic structure of CaAl₂Si₂O₈, and on further increase of y, the system undergoes a compositionally induced phase transition from triclinic to monoclinic structure. For Ca_0.96-yMg_yAl₂Si₂O₈: 0.04Eu²⁺ (y = 0.10, 0.30, 0.50, 0.70, 0.90) system, for z ≦ 0.03, all the compositions are of triclinic structure of CaAl₂Si₂O₈. With the further increase of z, other phase appears. The emission spectra of these phosphors show blue shift with the introduction of Sr²⁺ ions, and red shift with Mg²⁺ ions. The reason may be due to the difference ionic radii of Mg²⁺, Ca²⁺, Sr²⁺. These phosphors show excellent blue emission and broad excitation band in near-UV (ultraviolet) range. They may be potential phosphors for near-UV light-emitting diodes (LEDs).

Abstract: We report the demonstration of a GaN-based planar metal-semiconductor-metal (MSM) ultraviolet photodetector (PD). The MSM PD with semitransparent interdigitated Schottky electrodes is fabricated on low-defect-density GaN homoepitaxial layer grown on bulk GaN substrate by metal-organic chemical vapor deposition. The dislocation density of the GaN homo-epilayer characterized by cathodoluminescence mapping technique is ~5×10⁶ cm⁻². The PD exhibits a low dark current density of ~4.1×10⁻¹⁰ A/cm² and a high UV-to-visible rejection ratio up to 5 orders of magnitude at room temperature under 10 V bias. Even at a high temperature of 425 K, the dark current of the PD at 10 V is still <1×10⁻⁹ A/cm² with a reasonable UV-to-visible rejection ratio more than 3×10⁴, indicating that such kind of PDs are suitable for high temperature operation.

Abstract: To increase the energy efficiency and reduce the cost, the DC-Microgrids will have a very promising future in the power supply systems. In this paper, two power supply patterns for modern appliances, the central rectifier pattern and the distributed rectifier pattern, are investigated and compared. A concept of equivalent efficiency of diode bridge rectifier for DC-powered appliances is introduced and then it is applied in the model simplification. A Curved-Load model is constructed which is based on the specific efficiency characteristics of diode bridge rectifier in a particular current range and the statistics for appliance’s energy consumption as a percentage of the total. Using the Curved-Load model, the comparison of two microgrid system models was conducted with the help of simulations using Ansoft Simplorer 9.0 aiming to examine the conversion efficiency of rectifier patterns.

Abstract: In this paper, an oscillation center fast positioning method and the criterion that determines whether a system is out-of-step are combined together to put forward a compound oscillation center positioning and splitting criterion with predicting function. Simulation of a classical numerical example of four-machine system in two regions and an actual example of central China-north China power grid proves that this method can pre-locate lines where oscillation center lies after out-of-step operation of the system when the system is oscillating intensely but still keeps synchronized.

Abstract: This paper introduced a coastal wave energy power generation and its unique dual channel structure, in which two–way coastal current was transformed into single direction rotation of the impeller. Also according to coastal wave energy characteristics, the paper analyzed relationship between inshore sea water kinetic energy and the wave amplitude away from the coast. In addition, the water velocity and flow area of equipment through power generation equipment are studied.