753 research outputs found
Cluster Heat Bath Algorithm in Monte Carlo Simulations of Ising Models
We have proposed a cluster heat bath method in Monte Carlo simulations of
Ising models in which one of the possible spin configurations of a cluster is
selected in accordance with its Boltzmann weight. We have argued that the
method improves slow relaxation in complex systems and demonstrated it in an
axial next-nearest-neighbor Ising(ANNNI) model in two-dimensions.Comment: 10 pages, REVTeX, 2 figures, to appear in Phys.Rev.Let
KDM2 proteins constrain transcription from CpG island gene promoters independently of their histone demethylase activity
Wellcome Trust [102349/Z/13/Z to A.H.T., 099677/Z/12/Z to H.W.K., 098024/Z/11/Z, 209400/Z/17/Z to R.J.K.]; Lister Institute of Preventive Medicine; European Research Council [681440]; Japan Agency for Medical Research and Development, AMEDCREST Programme. Funding for open access charge: Wellcome Trus
Development and operational experience of magnetic horn system for T2K experiment
A magnetic horn system to be operated at a pulsed current of 320 kA and to
survive high-power proton beam operation at 750 kW was developed for the T2K
experiment. The first set of T2K magnetic horns was operated for over 12
million pulses during the four years of operation from 2010 to 2013, under a
maximum beam power of 230 kW, and protons were exposed to
the production target. No significant damage was observed throughout this
period. This successful operation of the T2K magnetic horns led to the
discovery of the oscillation phenomenon in 2013 by
the T2K experiment. In this paper, details of the design, construction, and
operation experience of the T2K magnetic horns are described.Comment: 22 pages, 40 figures, also submitted to Nuclear Instrument and
Methods in Physics Research,
Proposal of C-core Type Transverse Flux Motor for Ship Propulsion – Increasing Torque Density by Dense Stator Configuration –
Electric ship propulsion system has been drawing attention as a solution for savings in energy and maintenance costs. The system is mainly composed of motor, converter and gearbox and required for high torque at low speed. In this situation, transverse flux motors (TFMs) have been proposed to fulfill the low-speed high-torque characteristic due to suitable for short pole pitch and large number of poles to increase torque output. In this trend, we have proposed C-core type motors taking advantage of TFMs’ structure. In this manuscript, a simple design method based on the magnetic-circuit theory and simple modeling of the motor is proposed to search a design parameter for maximizing torque as a pre-process of numerical study. The method takes into consideration the effects of magnetic leakage flux, magnetic saturation and pole-core combination in accordance with the systematic theory. The simple modeling is conducted based on a dense armature structure in previous axial flux motors (AFMs) applied to the new motor design. The validity of the method is verified by 3-D finite element analysis (FEA) and relative error is at most 20%. The minimalist design is shown to be advantageous for effective use in 3-D FEA. As a detailed design by the FEA, high torque density and low cogging to output ratio can be achieved simultaneously in the proposed machine
Modification of the Shower Database of the IAU Meteor Data Center
The Shower Database (SD) of the Meteor Data Center (MDC) has been operating
for 15 years and is used by the entire community of meteor astronomers. It
contains meteor showers categorised in individual lists on the basis of their
status. Since the inception of the SD, no objective rules for moving showers
between individual lists have been established. The content of the SD has not
yet been checked for the correctness of the meteor data contained therein. Our
aims are (1) to formulate criteria for nominating meteor showers for
established status, (2) to improve the rules for the removal of showers, (3) to
verify and enhance the content of the SD, and (4) to improve the user area of
the MDC SD. The criteria for moving showers from the Working list to the Lists
of established or removed Showers were generated using an empirical evaluation
of their impact on the registered showers. The correctness of the parameters of
each stream included in the SD was checked by comparing them with the values
given in the source publications. We developed a set of criteria for nominating
showers to be established. We objectified rules for the temporary and permanent
removal of meteor showers from the Working list. Both of our proposed new
procedures were approved by a vote of the commission F1 of the IAU in July
2022. We verified more than data records of the MDC SD and introduced
1700 corrections. We included new parameters for shower characterisation.
As a result of our verification procedure, 117 showers have been moved to the
List of removed showers. As of October 2022, the SD contains 923 showers, 110
of which are in the List of established Showers and 813 are in the Working
list. We also improved the user area of the SD and added a simple tool to allow
a quick check of the similarity of a new shower to those in the database
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