Improved Blind Multiuser Detection Algorithm Based on Minimum Output Energy

Based on minimum output energy,an improved blind multiuser detection algorithm is proposed by the use of Hopfield neural network.Compared with traditional algorithms,the proposed algorithm does not need the circuit for constraints.The resources are greatly saved and the complexity is reduced as well.The simulation results show that the performance of the improved algorithm is similar to that of the optimal multiuser detection algorithm which is not suitable for the mobile station.Compared with the traditional gradient blind multiuser detection algorithm,the convergence speed of the improved algorithm is quickened.

Energy Giant Expands Gas Output to Meet Growing Demand for Cleaner Fuel

China National Petroleum Corporation(CNPC),Asia’s biggest oil and gas producer,will increase its investment in natural gas exploration and production,pipeline construction and gas sales in the coming decade,betting big on the country’s thirst for the clean fuel.The stateowned company,which currently allocates 70

AP assembled on ultrafine aluminum particle and its application to NEPE propellant

Coating modification is an important way to enhance the reactivity of aluminum powder.In this paper,ammonium perchlorate and aluminum powder were assembled into energetic microunits by liquid deposition method.Spherical particles with AP as shell and ultrafine aluminum powder as the core(Al@AP)were gained.The micromorphology results show that the coated particles are about 5μm,and the coating layer is evenly distributed on the outer surface of aluminum powder,indicating a complete coating.The energetic microunits were implanted into the nitrate ester plasticizing adhesive system(NEPE)as solid phase fillers.The effect of filler on the rheological properties,safety,mechanical properties,thermal reaction and energy properties of the system was analyzed by comparing with the raw aluminum filler.The test results show that the rheological properties,mechanical properties and pressure index of NEPE containing system Al@AP meets the requirements of solid propellant charging.Compared with Al based propellant,the mechanical sensitivity and thermal sensitivity are decreased,the safety is better,and the explosion heat of the propellant is increased by 7.8%.The engine test shows that the specific impulse is increased by 1.2 s.Al@AP can improve the energy output and safety of NEPE propellant,and has potential application prospects in high-energy propellants.

Assessment of the Wind Energy Potential of Two Burundian Sites

1-year hourly wind speed data from two Burundian stations, namely Bujumbura and Muyinga, have been processed in this work to bring an efficient help for the planning and installation of wind energy conversion systems (WECS) at those localities. Mean seasonal and diurnal variations of wind direction and wind shear exponent have been derived. Two-parameter Weibull probability density functions (PDFs) fitting the observed monthly and annual wind speed relative frequency distributions have been implemented. As shown through three complementary statistical tests, the fitting technique was very satisfactory. A wind resource analysis at 10 m above ground level (AGL) has led to a mean power density at Bujumbura which is almost thirteen fold higher than at Muyinga. The use of the empirical power law to extrapolate wind characteristics at heights from 150 to 350 m AGL has shown that energy potential of hilltops around Muyinga was only suitable for small, individual scale wind energy applications. At the opposite, wind energy potential of ridge-tops and hilltops around Bujumbura has been found suitable for medium and large scale electricity production. For that locality and at those heights, energy outputs and capacity factors (CF or Cf) have been computed for ten selected wind turbines (WTs), together with costs of electricity (COE) using the present value of cost (PVC) method. Amongst those WTs, YDF-1500-87 and S95-2.1 MW have emerged as the best options for installation owing to their highest CF and lowest COE. Moreover, an analysis of those two quantities at monthly basis for YDF-1500-87 WT has led to its best performance in the dry season. Compared to the average present COE of household hydroelectricity consumption, results of this study have evidenced economical feasibility and benefit of WECS setting in selected Burundian sites in order to supplement traditional electricity sources.

Elastic energy storage technology using spiral spring devices and its applications:A review

Harvesting and storing energy is a key problem in some applications.Elastic energy storage technology has the advantages of wide-sources,simple structural principle,renewability,high effectiveness and environmental-friendliness.This paper elaborates the operational principles and technical properties and summarizes the appli-cability of elastic energy storage technology with spiral springs.Elastic energy storage using spiral spring can realize the balance between energy supply and demand in some applications.Continuous input-spontaneous out-put working style can provide simple energy sources for short-time energy supply,and provide strong moment impact and rapid start,or realize the energy conservation for reciprocating movement.Uniform output working style can realize energy output with uniform speed for timekeeping and load-driving.Random input working style can harvest and store random mechanical energy or convert small torque into a large moment to drive external loads.Finally,this paper proposes new researches and developments of elastic energy storage technology on new materials and structures,mechanical properties and structural dynamics analyses,design and control for new functions.

An investigation on stress distribution effect on multi- piezoelectric energy harvesters

With the fast development of piezoelectric materials and due to its green and renewable characteristics, the piezoelectric energy harvesting technology has been paid more and more attention by pavement engineers. The stress distribution will significantly affect the piezoelectric material performance. In this paper, the effects of multiple piezoelectric elements on the generation of electrical energy and output power are studied. In the case of constant external load, the number of the piezoelectric units does not necessarily produce more energy. When the same multi piezoelectric units work together, if the stress state of the piezoelectric units is different, the total output energy affected by the connection mode. For uneven stress distribution, the optimal output mode is that each of the piezoelectric units rectified before connected in parallel.