Reduced Representation of Spatial Harmonics for Motor Model Order Reduction Using Block Arnoldi Method

A motor model order reduction (MOR) based on the decomposition into stator and rotor domains requires a Fourier expansion of the gap field with a large of number harmonic components, which are handled by the multiport Cauer ladder network (CLN) method. This study proposes a block Arnoldi method to obtain a reduced representation of spatial harmonics. Efficient bases for reduced harmonic representation were generated based on the inductance matrices of CLNs of stator and rotor domains. The interaction between the stator and rotor domains was considered by exchanging the basis vectors. Simulation results show that the proposed method yields an efficient and accurate MOR of the induction motor

Higgs response and pair condensation energy in superfluid nuclei

The pairing correlation in nuclei causes a characteristic excitation, known as the pair vibration, which is populated by the pair transfer reactions. Here we introduce a new method of characterizing the pair vibration by employing an analogy to the Higgs mode, which emerges in infinite superconducting/superfluid systems as a collective vibrational mode associated with the amplitude oscillation of the Cooper pair condensate. The idea is formulated by defining a pair-transfer probe, the Higgs operator, and then describing the linear response and the strength function to this probe. We will show that the pair condensation energy in nuclei can be extracted with use of the strength sum and the static polarizability of the Higgs response. In order to demonstrate and validate the method, we perform for Sn isotopes numerical analysis based the quasi-particle random phase approximation to the Skyrme-Hartree-Fock-Bogoliubov model. We discuss a possibility to apply this new scheme to pair transfer experiment.Comment: 31 pages, 9 figure

Model Order Reduction of Cage Induction Motor With Skewed Rotor Slots Using Multiport Cauer Ladder Network Method

A method for efficiently deriving a reduced-order model of a cage induction motor (IM) with skewed rotor slots is proposed based on the multiport Cauer ladder network (CLN) method. This article presents several formulations of the multiport CLN method for the skewed rotor, in which the continuity of the bar currents and the space harmonics included in the air-gap flux density waveform are treated differently. The effectiveness of the developed methods was verified from the viewpoints of computational accuracy and cost through application to a practical cage IM with skewed rotor slots

Reduced Order Modeling Based on Multiport Cauer Ladder Network for Space Harmonics of Air-gap Flux Density in Cage Induction Motor

This study investigated an efficient procedure for developing an accurate behavioral model of a cage induction motor (IM) based on the multiport Cauer ladder network (CLN). The CLN method was applied to a cage IM with semi-closed rotor slots as a model order reduction technique and a method for selecting the appropriate space harmonics included in the air-gap flux density, which is necessary for a multiport CLN method for induction machines, was discussed. Then, the developed approach was applied to the transient analysis of the cage IM coupled with a control system, and its effectiveness in terms of computational accuracy and cost was investigated

Cauer Ladder Network with Constant Basis Functions for Eddy Current Problems Involving Conductor Movement

This article proposes a Cauer ladder network with constant basis functions for eddy current problems involving translational movements. The analysis domain is decomposed into two domains: the stator part and the mover part. The Cauer ladder network method is applied to each domain to derive circuit parameters and corresponding basis functions to reconstruct the eddy current and compute the Lorentz force. Interactions between the two domains are modeled by current-controlled voltage sources connected to each stage of the Cauer ladder network. The gains of the current-controlled voltage sources are computed by numerical integration of the vector potential induced by the coil. An analysis of the TEAM Workshop Problem 28 was performed, and the results were validated by comparing them with those obtained by the commercially available software and showed a significant reduction in computational time

Photonic-crystal nano-photodetector with ultrasmall capacitance for on-chip light-to-voltage conversion without an amplifier

The power consumption of a conventional photoreceiver is dominated by that of the electric amplifier connected to the photodetector (PD). An ultralow-capacitance PD can overcome this limitation, because it can generate sufficiently large voltage without an amplifier when combined with a high-impedance load. In this work, we demonstrate an ultracompact InGaAs PD based on a photonic crystal waveguide with a length of only 1.7 μm and a capacitance of less than 1 fF. Despite the small size of the device, a high responsivity of 1 A/W and a clear 40 Gbit/s eye diagram are observed, overcoming the conventional trade-off between size and responsivity. A resistor-loaded PD was actually fabricated for light-to-voltage conversion, and a kilo-volt/watt efficiency with a gigahertz bandwidth even without amplifiers was measured with an electro-optic probe. Combined experimental and theoretical results reveal that a bandwidth in excess of 10 GHz can be expected, leading to an ultralow energy consumption of less than 1 fJ/bit for the photoreceiver. Amplifier-less PDs with attractive performance levels are therefore feasible and a step toward a densely integrated photonic network/processor on a chip

Development of complex hydrides for fast ionic conduction

Complex hydrides have been attracting much attention as solid-state fast ionic conductors since we reported the fast lithium ionic conduction in LiBH4 [1]. The development of fast ionic conductors is important because of their potential applications as solid electrolytes in rechargeable batteries [2]. We have worked on the development of lithium ionic conductors as well as sodium ionic conductors of complex hydrides. Please click Additional Files below to see the full abstract

Long-term effect of external beam radiotherapy of optic disc hemangioma in a patient with von hippel-lindau disease

An 18-year-old woman with a 2-year history of hypertension and headache was diagnosed with noradrenalin-secreting bilateral adrenal pheochromocytomas with paragangliomas in the background of von Hippel-Lindau disease with family histories and a missense mutation, 712C to T (Arg167Trp) in the VHL gene. She had optic disc hemangioma in the left eye which gradually enlarged and caused serous retinal detachment on the macula in one year. Low-dose external beam radiation (20 Gy) was administered to the left eye using a lens-sparing single lateral technique. She underwent craniotomy for cerebellar hemangioblastoma at the age of 22 years and total pancreatectomy for multiple neuroendocrine tumors at the age of 24 years. In the 6-year follow-up period after the radiotherapy, the optic disc hemangioma gradually reduced in size and its activity remained low, allowing good central vision to be maintained. External beam radiation is recommended as a treatment option for the initial therapy for optic disc hemangioma