A new solution to wireless sensor network density control problem

In this paper, we proposed a scheme based on Monte Carlo algorithm to test whether or not the nodes are redundant for realizing the node density control in the sensor network. The computational complexity is only O(n). We also established the coverage collision detection and back-off mechanism applied in the wireless sensor network. The simulation results show that the system can cover all the interested area with the smallest number of nodes and a coverage void will not appear during the course of state-transition. The coverage collision detection and back-off mechanism proposed in this article can be applied when the nodes have either synchronous or asynchronous mechanism. It also provides a stable stage with the length of the time that can be adjusted.

Particle mixing behavior of fine coal in density control of gas-solid separation fluidized bed

In a gas-solid separation fluidized bed,mixing of fine coal is necessary to achieve a suitable bed density to enable effective separation of low rank coal.On the basis of a variety of mixture models,a gas-solid separation fluidized bed was judged,where fine coal particles of 0.6-1.0mm were uniformly mixed with magnetite powder.High-speed dynamic camera technology was combined with a slump-sampling method to study the mixing process of the fine coal in the fluidized bed.These results showed that limitations of the fluidized bed structure cause the mixing process to be dominated by lateral diffusion and supplemented by axial diffusion.Axial diffusion was mainly achieved through the ascension of bubbles,whereas lateral diffusion was determined by the bursting action of the gas bubbles at the surface of the bed and the undulating characteristics of the bed.The effective lateral diffusion coefficient increased exponentially with gas velocity but had no strong relationship with the bed height.As the feed point moved toward the center,fine coal began to diffuse to both sides,which shortened the time for the bed density stabilization from 20 to 5 min.The bed density of the layer was stabilized at approximately 1.75 g/cm3.The separation efficiency of the gas-solid separation fluidized bed containing binary mixtures was more obvious for 6-50 mm raw coal,with a probable error E of 0.16.

Controlled Size and Density Distribution of Nanoparticles by Thermal Ammonia Etching Method

Nickel nanometer catalyst thin films were prepared on SiO2/Si substrates using sputtering coater. The effects of ammonia pretreatment on the catalyst films from continuous film to the nanoparticles were investigated. The nanostructures of the Ni thin films as a function of the catalyst film original thickness, the pretreatment time and temperature were discussed. The optimum parameters of etching process were obtained, and the functional mechanism of ammonia was primarily analyzed. Scanning electron microscopy （SEM） and atomic force microscopy （AFM） were used to evaluate the obtained nanoparticles. It is demonstrated that the controlled size and density distribution of the nanoparticles can be achieved by employing ammonia etching method.

Ligand density control boosts the efficiency of all-inorganic CsPbBr3 perovskite nanocrystal based light emitting diodes

Lead halide perovskites attracted a lot of attention in the last several years,with a focus gradually shifting from the record power conversion efficiencies reported for photovoltaic devices based on thin perovskite films[1]towards superior

Controlling the probability density of quantum systems

A new method to design a quantum controller which directly controls the probability density function（PDF） of quantum systems is proposed.Based on the quantum model from the PDF perspective,two specific control algorithms are proposed with uniform and non-uniform fields,respectively.Then a detailed control algorithm with convergence analysis is given for the small error case.By appropriately estimating the selected Lyapunov function,more accurate control effect is achieved.The proposed scheme provides a constructive method to find appropriate parameters for controller design.

Shape control on probability density function in stochastic systems

A novel strategy of probability density function （PDF） shape control is proposed in stochastic systems. The control er is designed whose parameters are optimal y obtained through the improved particle swarm optimization algorithm. The parameters of the control er are viewed as the space position of a particle in particle swarm optimization algorithm and updated continual y until the control er makes the PDF of the state variable as close as possible to the expected PDF. The proposed PDF shape control technique is compared with the equivalent linearization technique through simulation experiments. The results show the superiority and the effectiveness of the proposed method. The control er is excellent in making the state PDF fol ow the expected PDF and has the very smal error between the state PDF and the expected PDF, solving the control problem of the PDF shape in stochastic systems effectively.

The Construction of Plasma Density Feedback Control System on J-TEXT Tokamak

The plasma density feedback control system（PDFCS） has been established on the Joint Texas Experimental Tokamak（J-TEXT） for meeting the need for an accurate plasma density in physical experiments.It consists of a density measurement subsystem,a feedback control subsystem and a gas puffing subsystem.According to the characteristic of the gas puffing system,a voltage amplitude control mode has been applied in the feedback control strategy,which is accomplished by the proportion,integral and differential（PID） controller.In this system,the quantity calibration of gas injection,adjusted responding to the change of the density signal,has been carried out.Some experimental results are shown and discussed.

Iterative learning control approach for ramp metering

An iterative learning control scheme is developed to the traffic densitycontrol in a macroscopic level freeway environment. With rigorous analysis, the proposed intelligentcontrol scheme guarantees the asymptotic convergence of the traffic density to the desired one. Thecontrol scheme is applied to a freeway model, and simulation results confirm the efficacy of theproposed approach.

Hellinger distance based probability distribution approach to performance monitoring of nonlinear control systems

Control performance monitoring has attracted great attention in both academia and industry over the past two decades. However, most research efforts have been devoted to the performance monitoring of linear control systems, without considering the pervasive nonlinearities(e.g. valve stiction) present in most industrial control systems. In this work, a novel probability distribution distance based index is proposed to monitor the performance of non-linear control systems. The proposed method uses Hellinger distance to evaluate change of control system performance. Several simulation examples are given to illustrate the effectiveness of the proposed method.

Biological Characteristics and Comprehensive Prevention and Treatment Methods of Acantholyda piceacola Xiao et Zhou

[Objective] The paper was to clear biological characteristics and comprehensive prevention and treatment methods of Acantholyda piceacola Xiao et Zhou. [Method] Through captive observation and field survey,the current situation,life history and life habits of A. piceacola were investigated; the occurrence degree of A. piceacola in various regions and the relationship between soil depth and number distribution of A. piceacola were studied. Moreover,the contrast test of a variety of control measures was conducted. [Result] A. piceacola needed one year or more to complete a generation; there were significant differences in insect plant rate and extremely significant differences in population density among different plots. Trunk injection and foliar spraying conducted before the forth larval stage had good protection effects on needles of Picea mongolica; trunk injection with 14% imidacloprid · dichlorvos at egg stage received the best control effect,the loss rate of needles was the lowest of 8. 43%,so the method could be massively popularized in the future. [Conclusion]The results provide a reference for the control of A. piceacola.