Advanced Materials Research Vols. 760-762

Abstract: We design a new two-sided coupling channel drop filter (CDF) based on a two-dimensional (2D) photonic crystal (PC). Three channels formed by line defects for light propagation, two L4 resonators positioned at both sides of the input waveguide for light coupling, and one point defect micro-cavity in the bus waveguide for wavelength-selective reflection are introduced into the PC structure. The optical characteristics of this proposed structure are calculated by finite-difference time-domain (FDTD) method combined with the perfectly matched layers (PMLs) as the boundary conditions. Three wavelengths centered at 1550, 1575 and 1610 nm within the limit of communication windows are successfully separated in three channels by adjusting the size of coupling rods and the positions of L4 resonators and micro-cavity. High transmission efficiency and more than 20 nm channel spacing are achieved. These demonstrate that our proposed structure is suitable for photonic integrated circuits (PICs) and coarse wavelength division multiplexing (WDM) optical communication systems.

Abstract: In this paper, a new mechanism of plasma radiation optics-ammunition inspired by electrically exploding wires blasting in inert gases is studied. The simulation results indicate that, plasma radiation intensity increased by Mach-number of shock waves, and in all insert gases, argons Mach-number of shock waves is the highest. Silver is the best in common metal materials, and the exploding time and current peak is about linear with the number of wires. And the simulation results agree with the known experiment data and are important to the study of strong pulsed IR optics-ammunition.

Abstract: The electronic properties and the optical properties of wurtzite InN are studied by the first-principles calculations based on the density functional theory. The calculations are based on the Generalized-Gradient Approximation (GGA) and implemented in Plane Wave Self-Consist Field (PWSCF). The optical properties of InN are investigated by the pseudo-potential method with PBEsol-GGA within the WIEN2K program. Band structure, density of states and dielectric functions are calculated detailedly. The energy transitions are observed and compared existing data at critical points. Moreover the new peak in between the region 12 eV to 14 eV should be due to transitions from the In-5p states to the N-2s states.

Abstract: The luminous efficiency do make four impact factors confused such as existing of dissipated light, ability for transmission of lighting sources, distortion of visual effects and different values of power choosing during the luminous efficiency comparison under its current definition. In this paper, the equivalent luminous efficiency was introduced based on the discussion of these factors which maintains the form of current definition of luminous efficiency while it sets the equivalent coefficient to make test results comparable under different measurement conditions, so as to be clear when we compare and evaluate the properties of energy-saving and luminescence of luminaries.

Abstract: This paper reports the design and analysis of a novel pyramidal horn antenna based on Micro­electromechanical Systems (MEMS) technology, which is used in terahertz (THz) applications. The structure of the antenna includes two parts, pyramidal horn and inverted pyramidal horn for feed, the fabrication of the structure needs only one wafer, and the antenna can be easily integrated with other parts of on-chip circuits. There are many tunable parameters of the horn, so that high performance THz antenna can be achieved by optimizing these parameters. The proposed antenna can be manufactured by MEMS processing with low fabrication cost, suitable for many terahertz systems.

Abstract: The LED lamps replace traditional lamps is the direction of development domestic and abroad.It mainly introduced the LED lamp brightness control method from the aspect of software, then research and production of the LED efficient drive based on a IC chip digital boost constant current regulator, for the actual driving high power LED. It was realized 6 level control on the brightness of LED. The microcontroller controls D/A converter to make the output different voltage values through software programming, and then adjusts the DC/DC conversion circuit current size, finally implements LED brightness control. The experimental makes it possible to have the lamp with adjustable brightness, energy saving, achieve a wide range of voltage, current constant and so on.

Abstract: In order to solve the heat dissipation problem of LED (light-emitting diode) downlight, CFD thermal simulation software was used to establish LED downlight dissipation model. Materials thermal conductivity, thermal resistance, thermal emissive values, heat load forms and other factors were all taken in considered, and then numerical simulation combined with laboratory measurement methods was used to analysis the lamps dissipation. Based on this method, focused on the dissipation effect with different LED quantities and LED ring distances, and then optimized light source layout of current LED downlight products. After experimental verification, LED working temperatures were more ideal after the light source layout optimized, and it can improve the LED lamp lifetime effectively, this result also has important practice significance in the future LED downlight design process.

Abstract: In order to improve the efficiency of photovoltaic generation as well as the power quality, grid-connected inverters for PV generation research was carried out for photovoltaic maximum power point tracking. Based on some current studies on the incremental conductance method, an advanced incremental conductance control algorithm was proposed, which can track maximum power point rapidly and accurately. The oscillation phenomenon, which exists near the maximum power point, was improved at a great extent, so to the efficiency of photovoltaic cells generation electricity. The inverter control system has an advantage in its high speed and flexibility by applying advanced control algorithm. And the source harmonic current is remarkably reduced. In addition, the power factor is enhanced and the power quality is improved. Finally, according to the principle of inverter control system and based on the analysis on the mathematical model of photovoltaic inverter, a simulation model of that is established based on MATLAB/SIMULINK.

Abstract: According to high accuracy demand in the measurement field, this paper designs a high precision inertial measurement system by using DSP and ARM processor to realize carrier-phase differential GPS/INS integrated navigation. This paper chooses Kalman filter to estimate the systematic error, uses closed loop method to correct, and carries out carrier-phase differential GPS/INS data fusion. Through manipulating actual measurement data, the integrated navigation results indicate that position accuracy reaches cm level; velocity accuracy reaches cm/s level and attitude achieves high precision. The experiment proves the feasibility and effectiveness of carrier-phase differential GPS/INS integrated navigation system.

Abstract: this paper presents the design and realization of wireless sensor network gateway nodes based on s3c2410 Processor. And introduced the design of gateway hardware and software. Also introduced the implementation method of software. A new data transmit protocol was designed to eliminate the differences between ZigBee protocol and TCP/IP protocol, and this paper also designed a data transmit management module and data communicate module. This gateway can convert the data between ZigBee wireless sensor network and internet. This gateway has a good extensibility.