High efficiency multivibrator Patent

Improved semiconductor multivibrator circuit which approaches 100 percent efficienc

High efficiency multifrequency feed

Antenna systems and particularly compact and simple antenna feeds which can transmit and receive simultaneously in at least three frequency bands, each with high efficiency and polarization diversity are described. The feed system is applicable for frequency bands having nominal frequency bands with the ratio 1:4:6. By way of example, satellite communications telemetry bands operate in frequency bands 0.8 - 1.0 GHz, 3.7 - 4.2 GHz and 5.9 - 6.4 GHz. In addition, the antenna system of the invention has monopulse capability for reception with circular or diverse polarization at frequency band 1

High-efficiency device research

Progress on research in high-efficiency silicon solar cells is presented. Topics addressed include: recombination measurement techniques, doped crystals, minority carrier transport, oxygen process in solar cells, solar cell models, loss mechanics in solar cells, high-efficiency metal insulators, dendritic web cells, and surface and bulk loss reduction by low-energy hydrogen doping

High-efficiency silicon solar cells

Fabrication and characterization of high-efficiency metal insulator, n-p (MINP) cells is described. Particular attention was paid to development of measurement methods for surface recombination and density of surface states. A modified Rosier test structure was used successfully for density of surface states. Silicon oxide and silicon nitride passivants were studied. Heat treatment after plasma enhanced chemical vapor deposition (CVD) of silicon nitride was shown to be beneficial. A more optimum emitter concentration profile was modeled

Implementation of High Efficiency, High Lifetime and Low Cost Converter for an Automatic Photovoltaic Water Pumping Station

A novel idea of photovoltaic (PV) energy based converter for water pumping system without the USAge of fuel cells or batteries. In proposed system, the design of a three phase induction motor drive is directly supplied by using photovoltaic system energy. Presence of a three phase induction motor has better performance with optimized efficiency compared to the commercial water pumping system of DC motor. The developed resonant of Two Inductor Boost Converter (TIBC) and voltage quadruple with three phase Voltage Source Inverter (VSI) are based on the current fed multi resonant converter. Low input current ripple and high voltage gain are the features of TIBC. So the classical topology used to improve the system with a constant duty cycle control and a non dissipative snubber circuit along with a hysteresis controller to improve its efficiency. Due to the non existence of electrolytic capacitors the system is required to have a high lifetime and total system cost is low. As a result, in isolated locations the system has an optimistic solution and it provide water to poor societies

High efficiency architecture of ESCOT with pass concurrent context modeling scheme for scalable video coding

[[abstract]]In this work, we propose a high efficiency hardware architecture of embedded sub-band coding with optimal truncation (ESCOT) with pass concurrent context modeling (PCCM) scheme for wavelet-based scalable video coding (SVC). PCCM can merge the three-pass process of bit-plane coding into a single pass process. It improves the efficiency of the ESCOT algorithm and reduces the frequencies of memory access, which can reduce the power consumption. Furthermore we use the parallel architecture scheme of PCCM to encode 4 samples concurrently, which improves the operation speed and can reduce 40% of internal memory requirement. We use Artison TSMC 0.18 mum 1P6M standard cell library to design and implement the proposed concurrent context modeling. The simulation results indicate that PCCM can have an operation speedup of 9.5 compared to the standard context modeling of ESCOT, and it can operate for 1080 p with frame rate of 30 fps at clock rate of 125 MHz.[[conferencetype]]國際[[conferencedate]]20080518~20080521[[iscallforpapers]]Y[[conferencelocation]]Seattle, WA, US

High efficiency of seaplanes

A table is presented which includes data for calculating the index of efficiency. The author uses this data to conclude that seaplanes cannot be considered inferior to terrestrial airplanes

Superstructure high efficiency photovoltaics

A novel class of photovoltaic cascade structures is introduced which features multijunction upper subcells. These superstructure high efficiency photovoltaics (SHEP's) exhibit enhanced upper subcell spectral response because of the additional junctions which serve to reduce bulk recombination losses by decreasing the mean collection distance for photogenerated minority carriers. Two possible electrical configurations were studied and compared: a three-terminal scheme that allows both subcells to be operated at their individual maximum power points and a two-terminal configuration with an intercell ohmic contact for series interconnection. The three-terminal devices were found to be superior both in terms of beginning-of-life expectancy and radiation tolerance. Realistic simulations of three-terminal AlGaAs/GaAs SHEP's show that one sun AMO efficiencies in excess of 26 percent are possible

High efficiency magnetic bearings

Research activities concerning high efficiency permanent magnet plus electromagnet (PM/EM) pancake magnetic bearings at the University of Maryland are reported. A description of the construction and working of the magnetic bearing is provided. Next, parameters needed to describe the bearing are explained. Then, methods developed for the design and testing of magnetic bearings are summarized. Finally, a new magnetic bearing which allows active torque control in the off axes directions is discussed

High efficiency multi-junction solar cell design

Energy from the sun is the best option for electricity generation as it is abundantly available everywhere and sustainable source. Advance of Photovoltaic (PV) technology in recent years has made solar energy one of the practical alternative energy sources available in the energy market. In order to make the PV energy more affordable and cost effective, major focus of the research community and industry is improvement on power efficiency of PV systems. Early stage of solar panel manufacturing known as process technology plays a crucial role in achieving above limits. This paper presents a novel process technology for solar panel with 6 junctions