可控整流电路的EMI研究

本文通过试验对可控整流电路的电磁传导干扰进行了研究,重点研究了整流负载大小、负载性质以及触发角对传导干扰的影响。为整流电路的电磁干扰抑制滤波器的设计提供了有用数据。

A Novel Method of Nanocontact Fabrication for Andreev Reflection Measurement

A new method of nanocontact fabrication for Adreev reflection measurement based on the nanopore method using a SiN membrane with focused ion beam technique is presented. With this method, controllable, clean,tensionless nano-contacts for spin polarization probing can be obtained. Measurements of the fabricated samples show complicated spectral structures with a zero bias anomaly and dip structures from quasipartical interactions. A control sample of Co40Fe40B20 is measured with Nb tip method. None of the measured spectra can be explained satisfactorily by present theory. Further analysis of the contact interface and a more complete theory are needed to extract a reliable spin polarization message with the point contact Andreev reflection method.

Single-Stage Wide-Range CMOS VGA with Temperature Compensation and Linear-in-dB Gain Control

A novel wide-range CMOS variable gain amplifier （VGA） topology is presented. The proposed VGA is composed of a variable transconductor and a novel variable output resistor and can offer a high gain variation range of 80dB while using a single variable-gain stage. Temperature-compensation and decibel-linear gain characteristic are achieved by using a control circuit that provides a gain error lower than ±1.5dB over the full temperature and gain ranges. Realized in 0.25μm CMOS technology, a prototype of the proposed VGA provides a total gain range of 64.5dB with 55.6dB-linear range,a P-1dB varying from - 17.5 to 11.5dBm,and a 3dB-bandwith varying from 65 to 860MHz while dissipating 16.5mW from a 2.5V supply voltage.

Controllable Subspaces of Open Quantum Dynamical Systems

This paper discusses the concept of controllable subspace for open quantum dynamical systems. It is constructively demonstrated that combining structural features of decoherence-free subspaces with the ability to perform open-loop coherent control on open quantum systems will allow decoherence-free subspaces to be controllable. This is in contrast to the observation that open quantum dynamical systems are not open-loop controllable. To a certain extent, this paper gives an alternative control theoretical interpretation on why decoherence-free subspaces can be useful for quantum computation.

Controllable preparation of hierarchical NiO hollow microspheres with high pseudo-capacitance

Nickel oxide(NiO)hollow microspheres with hierarchical structure were fabricated through a process consisting of a self-assembling,hydrothermal reaction and calcination.The prepared NiO hollow microspheres composed of many nanoflakes,are about 2-3μm in diameter.The length of the NiO flakes,having clear edges,is about 500-700 nm,while the thickness is only about 40-50 nm.This indicates that the NiO microspheres possess a hierarchical structure that can provide porous channels to facilitate the transmission of both electrons and electrolyte ions.NiO microspheres exhibit a high specific capacitance of about 1340 F/g at a current density of 1 A/g and high capacitance retention about 96.5%after 1000 cycles.What’s more,the conductive mechanism of nickel oxide for electrochemical capacitor electrodes was also studied.

Effect of the Molecular Structure of Polymer Dispersants on Limestone Suspension Properties in Fine Grinding

Polymer dispersants are widely used as grinding aids to reduce the viscosity of mineral particle suspensions and to improve energy efficiency during fine grinding. The authors studied here the effects of polymer dispersants of different molecular structure on limestone suspension properties in wet stirred media milling. The polymers differed in their molecular weight and PDI （polydispersity index）. Two traditionally fractionated polymer dispersants having a high PDI （over 2） and one made by controlled radical polymerization having a low PDI （1.2） were tested. It was noticed that these dispersants worked as electrosteric stabilizers and prevented the agglomeration of ground limestone particles. Their addition allowed increased solids concentrations to be used in the grinding experiments and at the same time lowered the particle size and specific energy consumption. The particle sizes obtained were about 1 μm regardless of the dispersant or its dose. The dispersant with a low PDI reduced the viscosity more than did the high PDI dispersants. The results indicate that higher solids concentrations can be used at the same dispersant dose when a low PDI dispersant is used, leading to energy savings via increased throughput. Alternatively, a lower dose of low PDI polymer dispersant than of a high PDI polymer dispersant can be used at the same solids concentration.

Research on PCC Control Method for Ribbon-free Random Winding

Based on analyzing the overlap appearance of random winding, basic principles of ribbon-free random winding and parametric selections for anti-overlap are discussed. The ribbon-free random winding control system and its related hardware construction as well as its software design are introduced by applying PCC technology to high speed spinning machine of synthetic filament.

Self-adapting Scalable Differential Evolution Algorithm

Differential evolution(DE) demonstrates good convergence performance,but it is difficult to choose trial vector generation strategies and associated control parameter values.An improved method,self-adapting scalable DE(SSDE) algorithm,is proposed.Trial vector generation strategies and crossover probability are respectively self-adapted by two operators in this algorithm.Meanwhile,to enhance the convergence rate,vectors selected randomly with the optimal fitness values are introduced to guide searching direction.Benchmark problems are used to verify this algorithm.Compared with other well-known DE algorithms,experiment results indicate that this algorithm is better than other DE algorithms in terms of convergence rate and quality of optimization.

Managing Variable Transmittance Windowpanes byModel-Based Autonomous Control

The use of digitally activated, variable transmittance materials and artificial intelligence methods to building control will enhance the performance of buildings, and programmable components will change the traditional modes of architectural design, manufacturing and construction. In the presented key study, the architectural form and functionality of windows are revisited with a view to integrate current advances in material science, control systems engineering and human-computer interaction. The features of a building facade, involving a matrix of programmable windows that enables precise control of daylight, view and privacy in the interior of a house are discussed. Managing the variable transmittance materials of the facade by an autonomous high-level control system allows the optimization of the house performance based on real time data and the schedule of the inhabitants. Using constraint violations as a measure of success, the autonomous control of the house outperforms any existing deterministic control models.

On the Existence of an Optimal Control of Ship Automatic Steering Instruments

The existence of linear quadratic optimal control of ship automatic steering instruments is studied. Firstly, the sufficient conditions for the quadratic integrability of the solutions of linear second order time-variant differential equations are developed. Secondly, the optimal control form of the ship automatic steering instrument is obtained by using the dynamic programming method, which guarantees a minimal ship sway range, during long-distance navigation, by using as little energy as possible. Finally, based on the above mentioned sufficient conditions, the conditions for the realization of optimal control are obtained, which provides a foundation for choosing the weighted coefficients for optimal control in engineering.

Mixed-Weights Least-Squares Stable Predictive Control Algorithm with Soft and Hard Constraints

Mixed-weight least-squares (MWLS) predictive control algorithm, compared with quadratic programming (QP) method, has the advantages of reducing the computer burden, quick calculation speed and dealing with the case in which the optimization is infeasible. But it can only deal with soft constraints. In order to deal with hard constraints and guarantee feasibility, an improved algorithm is proposed by recalculating the setpoint according to the hard constraints before calculating the manipulated variable and MWLS algorithm is used to satisfy the requirement of soft constraints for the system with the input constraints and output constraints. The algorithm can not only guarantee stability of the system and zero steady state error, but also satisfy the hard constraints of input and output variables. The simulation results show the improved algorithm is feasible and effective.

UV Wavelength Tunable Output System Controlled by Microprocessor

UV wavelength auto-tuned tuned output system is realized by the difference method. Controlled by the microprocessor, output wavelength auto- tracking is achieved.Besides, equipment self-checking auto-positioning and temperature correct are realized,The wavelength tuned output efficiency in the experiment is better than 97 %.

Design Automation of the Manufacturing Process of a Mini Biodiesel Plant

The increasing pollution in the atmospheric layer has meant world-wide temperature variations, causing the melting of icecaps and floods, among other environmental factors. This change in temperature has been mainly caused by the indiscriminate emission of CO2, especially due to the rising number of vehicles in circulation. Researchers have identified that, among other types of fuel, diesel has the highest level of CO2 emission. Hence the need for the development of biodiesel, produced from oleaginous plants, aimed at reducing the emission of this harmful gas into the atmosphere, besides using renewable resources. However, as in any automation process, it is necessary to have sensors, actuators, and controllers, which together perform the automation and control of the production process. Besides that, there are other process variables to be accounted for, such as temperature, flow, and level. Considering such concept, and within the academic context, the creation process of a mini biodiesel plant will be described.

Recent advances in “living”/controlled radical polymerization of phosphorus-containing monomers and their potential applications

Special research attention has been paid to phosphorus-containing materials and their corresponding applications. This mini review considers recent publications devoted to the "living"/controlled radical(co)polymerization of phosphorus-containing monomers. In addition, different properties of the polymers involved in the phosphonate group in various chemical environments are demonstrated, and their potential applications are briefly discussed.

Path planning of a free-floating space robot based on the degree of controllability

An effective and more efficient path planning algorithm is developed for a kinematically non-redundant free-floating space robot(FFSR) system by proposing a concept of degree of controllability(DOC) for underactuated systems. The DOC concept is proposed for making full use of the internal couplings and then achieving a better control effect, followed by a certain definition of controllability measurement which measures the DOC, based on obtaining an explicit and finite equivalent affine system and singular value decomposition. A simple method for nilpotent approximation of the Lie algebra generated by the FFSR system is put forward by direct Taylor expansion when obtaining the equivalent system. Afterwards, a large-controlla- bility-measurement(LCM) nominal path is searched by a weighted A* algorithm, and an optimal self-correcting method is designed to track the nominal path approximately, yielding an efficient underactuated path. The proposed strategy successfully avoids the drawback of inefficiency inherent in previous path-planning schemes, which is due to the neglect of internal couplings, and illustrative numerical examples show its efficacy.

STABILIZATION OF THE QUADRUPLE INVERTED PENDULUM BY VARIABLE UNIVERSE ADAPTIVE FUZZY CONTROLLER BASED ON VARIABLE GAIN H_∞ REGULATOR

In this paper, the variable universe adaptive fuzzy controller based on variable gain Ha regulator （VGH∞R） is designed to stabilize a quadruple inverted pendulum. The VGH∞R is a novel robust gain-scheduling approach. By utilizing VGH∞R technique, a more precise real-time feedback gain matrix, which is changing with states, is obtained, Via the variable gain matrix 10 state variables of quadruple inverted pendulum are transformed into a kind of synthesis error （E） and synthesis rate of change of error （EC） at sampling time. Therefore, the dimension of the multivariable system is reduced and the variable universe adaptive fuzzy controller is built. Experiments illustrate the effectiveness of the proposed control scheme.

Large and controllable tunneling magnetoresistance in ferromagnetic/magnetic-semiconductor/ferromagnetic trilayers

In this work, we selected a magnetic-semiconductor as an interlayer and investigated the electronic transport properties in the ferromagnetic/ferromagnetic-semiconductor/ferromagnetic (FM/FS/FM) trilayers. The results indicate that the large TMR comparable to that in ferromagnetic/metal oxide/ferromagnetic sandwich can be obtained in the FM/FS/FM multilayers with considering the spin filter effect in the magnetic semiconductor layer. Moreover, the transmission coefficient and TMR can be tuned through thickness, Rashba spin-orbit coupling strength and molecular field of the magnetic semiconductor. Our calculations could provide a way to design the semiconductor spintronic devices with excellent and controllable properties.