Oscillation of Dzyaloshinskii–Moriya interaction driven by weak electric fields

Dzyaloshinskii–Moriya interaction(DMI) is under extensive investigation considering its crucial status in chiral magnetic orders, such as Néel-type domain wall(DW) and skyrmions. It has been reported that the interfacial DMI originating from Rashba spin–orbit coupling(SOC) can be linearly tuned with strong external electric fields. In this work, we experimentally demonstrate that the strength of DMI exhibits rapid fluctuations, ranging from 10% to 30% of its original value, as a function of applied electric fields in Pt/Co/MgO heterostructures within the small field regime(< 10-2V/nm). Brillouin light scattering(BLS) experiments have been performed to measure DMI, and first-principles calculations show agreement with this observation, which can be explained by the variation in orbital hybridization at the Co/MgO interface in response to the weak electric fields. Our results on voltage control of DMI(VCDMI) suggest that research related to the voltage control of magnetic anisotropy for spin–orbit torque or the motion control of skyrmions might also have to consider the role of the external electric field on DMI as small voltages are generally used for the magnetoresistance detection.

Determination and evaluation on field control efficacy of Trichogramma dendrolimi against Ostrinia furnacalis

The results of evaluation on field control efficacy of Trichogramma dendrolimi against Ostrinia furnacalis showed that the correction rates of Ostrinia furnacalis egg mass parasitism were 71.75% and 73.57%,the average control effect were 65.85% and 70.24%,the restoration yield loss rates were 6.78% and 7.97%,input-output ratio at 1:27.8 and 1:33.5 in Longjiang county of Heilongjiang province in 2009 and 2010,respectively.The technology is a integration of advanced,practical,environmental safety,effective biocontrol measures,embodies the "public plant protection,green plant protection" fully,has significant economic,social and ecological benefits.

Capillary Electrophoretic Separation of Proteins under the Control of Radial Electric Field

Separation of basic proteins was performed using a homemade field-modulated capillary electrophoresis system. The resolution. elution and even wall adsorption can be regulated by ad-lusting the radial rather than axial voltage applied. Selection of running buffer and pH was found to be critical.

Control Effect of Sex Pherom one Lure against the Asian Corn Borer( Ostrinia furnacalis) in Field

We studied the trapping effects on Ostrinia furnacalis from the aspects of different hanging heights and different color traps. The results suggested that the hanging height of 1.5 - 2.0 m received a better trapping effect, but trap color had little impact on trapping effect. The sex pheromone traps at different densities were placed in corn field. The results showed that sex pheromone lure could trap adult O. furnacalis, and it was feasible to apply sex pheromone in short term fore- cast. Meanwhile, it reduced the number of larvae and eggs, thereby reducing the damage of O. furnacalis. The lure number of 10 per hm2 was more appropriate, which could result in increasing yield of 8.61% compared with control

Upgraded Poloidal Field Control System for HT-7 Tokamak

This paper reviews how we have designed the upgraded poloidal field control system on HT-7 superconducting Tokmak by applying advanced computer technologies and Multivariable decoupling control theory. This paper emphasizes on designing the method of the control system,including system components and their functions.

Field Control Effects and Crop Safety Assessment of Triazole Fungicides on Apple Rust

In order to provide a reference basis for efficient prevention and control of apple rust,apple rust(Gymnosporangium yamadai)was used as the test material,the field control effects of six triazole fungicides with different concentrations and different application times on apple rust,and the safety of application in different periods on the crop were investigated in field trials.The results showed that the control effect and safety of myclobutanil were excellent.In the prevention test,the effects of myclobutanil 40%EC 2000 times and 4000 times dilutions in protecting apple leaves from G.yamadai infection reached more than 98%at 10 d after the second spraying in the fruitlet stage,and in the treatment test,the control effects of inhibiting the spread of leaf lesions were 90.89%and 87.17%at 16 d after the fourth spraying in the fruit expansion stage,respectively.The results of the crop safety test showed that when applying the triazole fungicides with different concentrations from the red bud stage to the fruit expansion stage of apple trees,there were no adverse effects on the leaves,branches,flowers and fruit,as well as no rust or deformity on the fruit surface.When spraying the fungicides from the red bud stage to the fruit expansion stage,except that the single fruit weights in the treatment of the 10%difenoconazole DC 2000 times and myclobutanil 40%EC 4000 times dilutions were reduced without a significant difference from the control,and the values of other treatments were all reduced by more than 9%compared with the control.When applying the fungicides during the fruit expansion period,none of the tested fungicide treatments had a significant effect on the fruit growth.

Controlling Three-Dimensional Electron-Electron Correlation via Elliptically Polarized Intense Laser Field

The three-dimensional electron-electron correlation in an elliptically polarized laser field is investigated based on a semiclassical model. Asymmetry parameter α of the correlated electron momentum distribution is used to quantitatively describe the electron-electron correlation. The dependence of α on elliptieity e is totally different in three directions. For the z direction （maJor polarization direction）, α first increases and reaches a maximum at ε = 0.275, then it decreases quickly. For the y direction in which the laser field is always absent, the ellipticity has a minor effect, and the asymmetry parameter fluctuates around α = -0.15. However, for the x direction （minor polarization direction）, α increases monotonously with ellipticity though starts from the same value as in the y direction when ε = 0. The behavior of α in the x direction actually indicates a transformation from the Coulomb interaction dominated correlation to the laser field dominated correlation. Therefore, our work provides an efficient way to control the three-dimensional electron electron correlation via an elliptically polarized intense laser field.

Controlling Fusion of Majorana Fermions in One-Dimensional Systems by Zeeman Field

We propose the realization of Majorana fermions （MFs） on the edges of a two-dimensional topological insulator in the proximity with s-wave superconductors and in the presence of transverse exchange field h. It is shown that there appear a pair of MFs localized at two junctions and that a reverse in the direction of h can lead to permutation of two MFs. With decreasing h, the MF states can either be fused or form one Dirac fermion on the π-junctions, exhibiting a topological phase transition. This characteristic can be used to detect physical states of MFs when they are transformed into Dirac fermions MFs is also given. localized on the π-junction. A condition of decoupling two

Controlling the Goos-H?nchen Shift via Incoherent Pumping Field and Electron Tunneling in the Triple Coupled InGaAs/GaAs Quantum Dots

We study the controlling of the Goos-Hanchen （GH） shifts in reflected and transmitted light beams in the triple coupled InGaAs/GaAs quantum dot （QD） nanostructures with electron tunneling and incoherent pumping field. It is shown that the lateral shift can become either large negative or large positive, which can be controlled by the electron tunneling and the rate of incoherent pump field in different incident angles. It is also demonstrated that the properties of the OH shifts are strongly dependent on the probe absorption beam of the intracavity medium due to the switching from superluminal light propagation to subluminal behavior or vice versa. Our suggested system can be considered as a new theoretical method for developing a new nano-optoelectronic sensor.

TEMPERATURE FIELD CONTROL PRINCIPLE AND CONTROL MODELS FOR CRYOGENIC MACHINING SYSTEM

Cryogenic machining is a new technology which makes use of the special mechanicalprcperties of niaterials in a cryogenic or a 'super cold' state for machining. The control of acryogenic machining system(CMS)is one of the key problems which need to be solved for practi-cal cryogenic machining A temperature field control principle is presented which calculates theheat source temperature in the light of the tool temperature field information, and a control mod-el of three-dimensional dynamic temperature field for CMS is established, and the boundary con-ditions and the heat source of temperature field in orthogonal cutting are discussed. Based on theinvestigation of the control feature and technique. a prototype system for controlling CMS is crea-ted.

Driving and Braking Control of PM Synchronous Motor Based on Low-resolution Hall Sensor for Battery Electric Vehicle

Resolvers are normally employed for rotor positioning in motors for electric vehicles, but resolvers are expensive and vulnerable to vibrations. Hall sensors have the advantages of low cost and high reliability, but the positioning accuracy is low. Motors with Hall sensors are typically controlled by six-step commutation algorithm, which brings high torque ripple. This paper studies the high-performance driving and braking control of the in-wheel permanent magnetic synchronous motor （PMSM） based on low-resolution Hall sensors. Field oriented control （FOC） based on Hall-effect sensors is developed to reduce the torque ripple. The positioning accuracy of the Hall sensors is improved by interpolation between two consecutive Hall signals using the estimated motor speed. The position error from the misalignment of the Hall sensors is compensated by the precise calibration of Hall transition timing. The braking control algorithms based on six-step commutation and FOC are studied. Two variants of the six-step commutation braking control, namely, half-bridge commutation and full-bridge commutation, are discussed and compared, which shows that the full-bridge commutation could better explore the potential of the back electro-motive forces （EMF）, thus can deliver higher efficiency and smaller current ripple. The FOC braking is analyzed with the phasor diagrams. At a given motor speed, the motor turns from the regenerative braking mode into the plug braking mode if the braking torque exceeds a certain limit, which is proportional to the motor speed. Tests in the dynamometer show that a smooth control could be realized by FOC driving control and the highest efficiency and the smallest current ripple could be achieved by FOC braking control, compared to six-step commutation braking control. Therefore, FOC braking is selected as the braking control algorithm for electric vehicles. The proposed research ensures a good motor control performance while maintaining low cost and high reliability.

PSO Based Controlled Six-phase Grid Connected Induction Generator for Wind Energy Generation

This paper deals a detailed performance investigation of asymmetrical six-phase grid connected induction generator(GCIG)in two proposed configurations in variable speed operation.During the system development,regulation of DC-link voltage has been proposed using particle swarm optimization(PSO)based PI controller,ensuring the power flow to utility grid through back to back converters.The closed loop operation of asymmetrical six-phase GCIG using indirect field oriented control in different configurations has been carried out in Matlab/Simulink environment.Analytical results have been verified using real time test results on virtual platform of Typhoon HIL supported with some experimental validation.

V-BILIPSCHITZ DETERMINACY OF WEIGHTED HOMOGENEOUS ANALYTIC FUNCTION-GERMS ON WEIGHTED HOMOGENEOUS REAL ANALYTIC VARIETIES

In this article, we provide estimates for the degree of V bilipschitz determinacy of weighted homogeneous function germs defined on weighted homogeneous analytic variety V satisfying a convenient Lojasiewicz condition.The result gives an explicit order such that the geometrical structure of a weighted homogeneous polynomial function germs is preserved after higher order perturbations.

Torque-based Optimal Acceleration Control for Electric Vehicle

The existing research of the acceleration control mainly focuses on an optimization of the velocity trajectory with respect to a criterion formulation that weights acceleration time and fuel consumption. The minimum-fuel acceleration problem in conventional vehicle has been solved by Pontryagin＇s maximum principle and dynamic programming algorithm, respectively. The acceleration control with minimum energy consumption for battery electric vehicle（EV） has not been reported. In this paper, the permanent magnet synchronous motor（PMSM） is controlled by the field oriented control（FOC） method and the electric drive system for the EV（including the PMSM, the inverter and the battery） is modeled to favor over a detailed consumption map. The analytical algorithm is proposed to analyze the optimal acceleration control and the optimal torque versus speed curve in the acceleration process is obtained. Considering the acceleration time, a penalty function is introduced to realize a fast vehicle speed tracking. The optimal acceleration control is also addressed with dynamic programming（DP）. This method can solve the optimal acceleration problem with precise time constraint, but it consumes a large amount of computation time. The EV used in simulation and experiment is a four-wheel hub motor drive electric vehicle. The simulation and experimental results show that the required battery energy has little difference between the acceleration control solved by analytical algorithm and that solved by DP, and is greatly reduced comparing with the constant pedal opening acceleration. The proposed analytical and DP algorithms can minimize the energy consumption in EV＇s acceleration process and the analytical algorithm is easy to be implemented in real-time control.

Creation of radially polarized optical fields with multiple controllable parameters using a vectorial optical field generator

A vectorial optical field generator(VOF-Gen) based on two reflective phase-only liquid crystal spatial light modulators enables the creation of an arbitrary optical complex field. In this work, the capabilities of the VOF-Gen in terms of manipulating the spatial distributions of phase, amplitude, and polarization are experimentally demonstrated by generating a radially polarized optical field consisted of five annular rings, the focusing properties of which are also numerically studied with vectorial diffraction theory. By carefully adjusting the relative amplitude and phase between the adjacent rings, an optical needle field with purely longitudinal polarization can be produced in the focal region of a high numerical aperture lens. The versatile method presented in this work can be easily extended to the generation of a vectorial optical field with any desired complex distributions.

C^l -G_V TRIVIALITY OF FUNCTION GERMS AND NEWTON POLYHEDRA

We provide estimates on the degree of C l GV determinacy （ G is one of Mather’s groups R or K ） of function germs which are defined on analytic variety V and satisfies a non-degeneracy condition with respect to some Newton polyhedron. The result gives an explicit order such that the C l geometrical structure of a function germ is preserved after higher order perturbations, which generalizes the result on C l G triviality of function germs given by M.A.S.Ruas.

Starting Control of Free Piston Stirling Linear Generator System Based on FOC

Aiming at the problem of poor system dynamic performance caused by low parameter matching in the coordinated control of Stirling engine and linear generator in the starting stage control of free piston Stirling linear generator system,a joint control method of free piston Stirling permanent magnet synchronous linear generator system based on field orientation control is proposed,based on the theoretical derivation of the mathematical model of the system and the principle of controller parameters setting,the simulation experiments of the system starting stage under several Stirling engine working conditions are carried out under simulation.The experimental results show that the stability and rapidity of the system are improved,and the dynamic response speed of generator parameters under different working conditions is accelerated,what fully verifies the correctness and effectiveness of the method.It provides an effective way to improve the control performance of the system and stabilize the power generation operation.

Optically Controlled Coercive Field of MAPbl_(3)/P(VDF-TrFE)Ferroelectric Composite Films

Ferroelectric polymers,such as poly(vinylidene fluoride-trifluoroethylene)[P(VDF-TrFE)or PVTF]have attracted growing interest in developing flexible devices because of their excellent ferroelectricity and piezoelectricity.High coercive field(E c)inherent to PVTF for switching its polarization,however,is not beneficial for practical memory or sensor device application.Different strategies,including irradiation and interface control,have been thus developed to reduce E c.Despite many efforts,a facile approach to tailoring intrinsic E_(c) of PVTF has not been documented.In this work,an optically controlled E_(c) was reported,which is achieved for the first time by introducing photosensitive MAPbI3 nanocrystals into PVTF matrix.When exposed to the irradiation of 532 nm laser light,a decreased E_(c) of the composites can be achieved reversibly by increasing the light density.The decreased level of E_(c) increases as the MAPbI3 content enhanced,and a 10.7%reduction of E_(c) can be achieved in 15%(mass fraction)MAPbI3/PVTF samples.These results could be attributed to loading an internal stress on PVTF,which was generated by the photostriction of MAPbI3 nanocrystals.This explanation was further supported by in-situ XRD results under irradiation of 532 nm laser light.Our findings may offer the opportunity to optically modulate the ferroelectric properties of PVTF composites for optimized device performances.

Flow field control for 2-meter high-speed free-jet wind tunnel

The 2-meter High-speed Free-jet Wind Tunnel(2 m HFWT)is China’s first large-scale open-jet trisonic wind tunnel.Compared to traditional closed high-speed wind tunnels,this wind tunnel is endowed with remarkable advantages of ample test chamber space,less interference from the tunnel wall,flexible model support mode,and adjustable continuous variation of the Mach number.Nevertheless,its unique structure makes traditional wind tunnel control methods difficult to apply and brings significant challenges to wind tunnel flow field control.In this paper,a flow field control system is designed for the 2 m HFWT by comprehensively using advanced control technologies such as neural network,gain scheduling,feedforward control,and adaptive control.Through practical application tests,it is proved that the proposed control system successfully solves the problem of high-precision flow field control under continual depletion of storage tank pressure,and realizes distinctive functions of adaptive static pressure matching and continuously varying Mach number at supersonic speed.In addition,due to the application of workflow technology,the flow field control system can flexibly adapt to the implementation of tests of different types and operation conditions,thus fully satisfying the needs of conducting various conventional and special tests in the 2 m HFWT.

Detection and targeted control of regional stress field for coal burst prevention

As coal burst normally occurs in the area of high stress concentration,it is of significance to study the features of regional stress field in coal mines.Primitive stress field,mining-induced stress field and their coupling effect are investigated through the methods of theoretical analysis,field measurement,numerical simulation and wave velocity CT inversion,and the relationship among regional stress field,high-energy seismic events and coal bursts are analyzed.Investigation of the 3#mining district in Xingcun coal mine shows that:(1)Though stress concentration changes in the mining process,several special areas witnesses stress concentration in the whole mining process,such as the rise pillar area,several syncline axis areas and large fault areas;(2)Coal burst occurrence and high-energy seismic events have a close relationship with regional stress field.Coal bursts and high-energy seismic events tend to occur in areas of stable stress concentration,such as the rise area,several syncline axis areas and large fault areas.Targeted control of stress field for coal burst prevention is developed based on stress field detection.The process of targeted control of stress field for coal burst prevention is:detection of regional stress field based mainly on wave velocity CT,identification of stress concentration,implementation of destress measures to control the identified stress concentration.This method of stress field control was applied to LW3306 working face in Xingcun coal mine and coal burst hazards were effectively controlled in LW3306.