Modeling and Analysis of Permanent Magnet Spherical Motors by A Multi-task Gaussian Process Method and Finite Element Method for Output Torque

Permanent magnet spherical motors (PMSMs) operate on the principle of the dc excitation of stator coils and three freedom of motion in the rotor. Each coil generates the torque in a specific direction, collectively they move the rotor to a direction of motion. Modeling and analysis of the output torque are of critical importance for precise position control applications. The control of these motors requires precise output torques by all coils at a specific rotor position, which is difficult to achieve in the three-dimension space. This article is the first to apply the Gaussian process to establish the relationship of the rotor position and the output torque for PMSMs. Traditional methods are difficult to resolve such a complex three-dimensional problem with a reasonable computational accuracy and time. This article utilizes a data-driven method using only input and output data validated by experiments. The multitask Gaussian process is developed to calculate the total torque produced by multiple coils at the full operational range. The training data and test data are obtained by the finite-element method. The effectiveness of the proposed method is validated and compared with existing data-driven approaches. The results exhibit superior performance of accuracy

Top-quark FCNC Productions at LHC in Topcolor-assisted Technicolor Model

We evaluate the top-quark FCNC productions induced by the topcolor assisted technicolor (TC2) model at the LHC. These productions proceed respectively through the parton-level processes g g -> t c_bar, c g->t, c g -> t g, c g -> t Z and c g -> t \gamma. We show the dependence of the production rates on the relevant TC2 parameters and compare the results with the predictions in the minimal supersymmetric model. We find that for each channel the TC2 model predicts a much larger production rate than the supersymmetric model. All these rare productions in the TC2 model can be enhanced above the 3-sigma sensitivity of the LHC. Since in the minimal supersymmetric model only c g -> t is slightly larger than the corresponding LHC sensitivity, the observation of these processes will favor the TC2 model over the supersymmetric model. In case of unobservation, the LHC can set meaningful constraints on the TC2 parameters.Comment: 5 pages, 4 fig

Neutral top-pion and top-charm production in high energy e+e−e^{+}e^{-} collisions

We calculate the contributions of the neutral top-pion, predicted by topcolor-assisted technicolor (TC2) theory, to top-charm production via the processes $\gamma\gamma \longrightarrow\bar{t}c$ and $e^{+}e^{-}\longrightarrow \gamma\gamma\longrightarrow \bar{t}c$ at the high energy linear $e^{+}e^{-}$ collider (LC) experiments. The cross section is of order $10^{-2}pb$ in most of the parameter space of TC2 theory, which may be detected at the LC experiments. So the process $e^{+}e^{-}\longrightarrow \bar{t}c$ can be used to detect the signature of TC2 theory.Comment: Latex file, 8 pages with 4 eps figures. to be published Phys.Lett.

Probing Topcolor-Assisted Technicolor from Like-sign Top Pair Production at LHC

The topcolor-assisted technicolor (TC2) theory predicts tree-level flavor-changing neutral-current (FCNC) top quark Yukawa couplings with top-pions. Such FCNC interactions will induce like-sign top quark pair productions at CERN Large Hadron Collider (LHC). While these rare productions are far below the observable level in the Standard Model and other popular new physics models such as the Minimal Supersymmetric Model, we find that in a sound part of parameter space the TC2 model can enhance the production cross sections to several tens of fb and thus may be observable at the LHC due to rather low backgrounds. Searching for these productions at the LHC will serve as an excellent probe for the TC2 model.Comment: 10 pages, 6 fig

Probing New Physics from Top-charm Associated Productions at Linear Colliders

The top-charm associated productions via $e^+ e^-$, $e^- \gamma$ and $\gamma \gamma$ collisions at linear colliders, which are extremely suppressed in the Standard Model (SM), could be significantly enhanced in some extensions of the SM. In this article we calculate the full contribution of the topcolor-assisted technicolor (TC2) to these productions and then compare the results with the existing predictions of the SM, the general two-Higgs-doublet model and the Minimal Supersymmetric Model. We find that the TC2 model predicts much larger production rates than other models and the largest-rate channel is $\gamma \gamma \to t \bar{c}$, which exceeds 10 fb for a large part of the parameter space. From the analysis of the observability of such productions at the future linear colliders, we find that the predictions of the TC2 model can reach the observable level for a large part of the parameter space while the predictions of other models are hardly accessible.Comment: discussions added (version in Eur. Phys. J. C

Climatic warming in China during 1901-2015 based on an extended dataset of instrumental temperature records

Monthly mean instrumental surface air temperature (SAT) observations back to the nineteenth century in China are synthesized from different sources via specific quality-control, interpolation, and homogenization. Compared with the first homogenized long-term SAT dataset for China by Cao et al. (2013), which contained 18 stations mainly located in the middle and eastern part of China, the present dataset includes homogenized monthly SAT series at 32 stations, with an extended coverage especially towards western China. Missing values are interpolated by using observations at nearby stations including those from neighboring countries. Cross validation shows that the mean bias error (MBE) is generally small and falls between 0.45°C and -0.35°C. Multiple homogenization methods and available metadata are applied to assess the consistency of the time series and to adjust inhomogeneity biases. The homogenized annual mean SAT series show a range of trends between 1.1 and 4.0°C/century in northeastern China, between 0.4 and 1.9°C/century in southeastern China, and between 1.4 and 3.7°C/century in western China to the west of 105E (from the beginning years of the stations to 2015). The unadjusted data include unusually warm records during the 1940s and hence tend to underestimate the warming trends at a number of stations. The mean SAT series for China based on the Climate Anomaly Method shows a warming trend of 1.56°C/century during 1901-2015, larger than those based on other currently available datasets

A Preliminary Study on Robot-Assisted Ankle Rehabilitation for the Treatment of Drop Foot

This paper involves the use of a compliant ankle rehabilitation robot (CARR) for the treatment of drop foot. The robot has a bio-inspired design by employing four Festo Fluidic muscles (FFMs) that mimic skeletal muscles actuating three rotational degrees of freedom (DOFs). A trajectory tracking controller was developed in joint task space to track the predefined trajectory of the end effector. This controller was achieved by controlling individual FFM length based on inverse kinematics. Three patients with drop foot participated in a preliminary study to evaluate the potential of the CARR for clinical applications. Ankle stretching exercises along ankle dorsiflexion and plantarflexion (DP) were delivered for treating drop foot. All patients gave positive feedback in using this ankle robot for the treatment of drop foot, although some limitations exist. The proposed controller showed satisfactory accuracy in trajectory tracking, with all root mean square deviation (RMSD) values no greater than 0.0335 rad and normalized root mean square deviation (NRMSD) values less than 6.7%. These preliminary findings support the potentials of the CARR for clinical applications. Future work will investigate the effectiveness of the robot for treating drop foot on a large sample of subjects

Neutrino Physics with JUNO

The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purposeunderground liquid scintillator detector, was proposed with the determinationof the neutrino mass hierarchy as a primary physics goal. It is also capable ofobserving neutrinos from terrestrial and extra-terrestrial sources, includingsupernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos,atmospheric neutrinos, solar neutrinos, as well as exotic searches such asnucleon decays, dark matter, sterile neutrinos, etc. We present the physicsmotivations and the anticipated performance of the JUNO detector for variousproposed measurements. By detecting reactor antineutrinos from two power plantsat 53-km distance, JUNO will determine the neutrino mass hierarchy at a 3-4sigma significance with six years of running. The measurement of antineutrinospectrum will also lead to the precise determination of three out of the sixoscillation parameters to an accuracy of better than 1\%. Neutrino burst from atypical core-collapse supernova at 10 kpc would lead to ~5000inverse-beta-decay events and ~2000 all-flavor neutrino-proton elasticscattering events in JUNO. Detection of DSNB would provide valuable informationon the cosmic star-formation rate and the average core-collapsed neutrinoenergy spectrum. Geo-neutrinos can be detected in JUNO with a rate of ~400events per year, significantly improving the statistics of existing geoneutrinosamples. The JUNO detector is sensitive to several exotic searches, e.g. protondecay via the $p\to K^++\bar\nu$ decay channel. The JUNO detector will providea unique facility to address many outstanding crucial questions in particle andastrophysics. It holds the great potential for further advancing our quest tounderstanding the fundamental properties of neutrinos, one of the buildingblocks of our Universe