899 research outputs found
Design of large power surface-mounted permanent-magnet motors using post-assembly magnetization
This paper reports the design process for the manufacture of higher power rare-earth permanent-magnet motors using post-assembly magnetization. With these machines, difficulties can be encountered in production using normal manufacturing processes due to the high intensity of rare-earth magnets that are pre-magnetized. Post-assembly magnetization utilizes the stator windings of a permanent-magnet motor to magnetize the magnets after complete assembly (so that the problem can be solved). However, with post-assembly magnetization, some parameters such as slot-fill factor, number of turns, wire diameter, etc., must be considered for the magnetization, as well as the motor operation. The machine design should be able to meet the required specification as a motor and ensure correct magnetization is possible. In this paper, a design process is described that incorporates the design considerations for post-assembly magnetization (for the requirements for complete magnetization) together with the design requirements for successful motor operation. A 6kW surface-mounted permanent-magnet motor is designed using the proposed process, and finite element analysis verifies the feasibility of the presented method. ©2007 IEEE
Local P T symmetry violates the no-signaling principle
Bender et al. [Phys. Rev. Lett. 80, 5243 (1998)] have developed PT-symmetric quantum theory as an extension of quantum theory to non-Hermitian Hamiltonians. We show that when this model has a local PT symmetry acting on composite systems, it violates the nonsignaling principle of relativity. Since the case of global PT symmetry is known to reduce to standard quantum mechanics A. Mostafazadeh [J. Math. Phys. 43, 205 (2001)], this shows that the PT-symmetric theory is either a trivial extension or likely false as a fundamental theory. © 2014 American Physical Society
Passive PT -symmetric couplers without complex optical potentials
© 2015 American Physical Society. In addition to the implementation of parity-time-(PT-) symmetric optical systems by carefully and actively controlling the gain and loss, we show that a 2×2 PT-symmetric Hamiltonian has a unitarily equivalent representation without complex optical potentials in the resulting optical coupler. Through the Naimark dilation in operator algebra, passive PT-symmetric couplers can thus be implemented with a refractive index of real values and asymmetric coupling coefficients. This opens up the possibility to implement general PT-symmetric systems with state-of-the-art asymmetric slab waveguides, dissimilar optical fibers, or cavities with chiral mirrors
A urinary Common Rejection Module (uCRM) score for non-invasive kidney transplant monitoring.
A Common Rejection Module (CRM) consisting of 11 genes expressed in allograft biopsies was previously reported to serve as a biomarker for acute rejection (AR), correlate with the extent of graft injury, and predict future allograft damage. We investigated the use of this gene panel on the urine cell pellet of kidney transplant patients. Urinary cell sediments collected from patients with biopsy-confirmed acute rejection, borderline AR (bAR), BK virus nephropathy (BKVN), and stable kidney grafts with normal protocol biopsies (STA) were analyzed for expression of these 11 genes using quantitative polymerase chain reaction (qPCR). We assessed these 11 CRM genes for their abundance, autocorrelation, and individual expression levels. Expression of 10/11 genes were elevated in AR when compared to STA. Psmb9 and Cxcl10could classify AR versus STA as accurately as the 11-gene model (sensitivity = 93.6%, specificity = 97.6%). A uCRM score, based on the geometric mean of the expression levels, could distinguish AR from STA with high accuracy (AUC = 0.9886) and correlated specifically with histologic measures of tubulitis and interstitial inflammation rather than tubular atrophy, glomerulosclerosis, intimal proliferation, tubular vacuolization or acute glomerulitis. This urine gene expression-based score may enable the non-invasive and quantitative monitoring of AR
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Evolution of superconductivity in K2-xFe4+ySe5: Spectroscopic studies of X-ray absorption and emission.
This study investigates the evolution of superconductivity in K2-xFe4+ySe5 using temperature-dependent X-ray absorption and resonant inelastic X-ray scattering techniques. Magnetization measurements show that polycrystalline superconducting (SC) K1.9Fe4.2Se5 has a critical temperature (T c) of ∼31 K with a varying superconducting volume fraction, which strongly depends on its synthesis temperature. An increase in Fe-structural/vacancy disorder in SC samples with more Fe atoms occupying vacant 4d sites is found to be closely related to the decrease in the spin magnetic moment of Fe. Moreover, the nearest-neighbor Fe-Se bond length in SC samples exceeds that in the non-SC (NS) sample, K2Fe4Se5, which indicates a weaker hybridization between the Fe 3d and Se 4p states in SC samples. These results clearly demonstrate the correlations among the local electronic and atomic structures and the magnetic properties of K2-xFe4+ySe5 superconductors, providing deeper insight into the electron pairing mechanisms of superconductivity
Constructing an index for brand equity : a hospital example
Author name used in this publication: Po-An J.J. Hsieh2010-2011 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe
Gender Dimorphism of the Cardiac Dysfunction in Murine Sepsis: Signalling Mechanisms and Age-Dependency
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.JC is supported by a jointly funded PhD-studentship of the China Scholarship Council (grant number 201206240146) and Queen Mary University of London (QMUL). SMC is supported by a Research Fellowship of the German Research Foundation (Deutsche Forschungsgemeinschaft; DFG CO 912/1-1). NSAP is, in part, supported by the Bart’s and The London Charity (753/1722). This work is supported, in part, by the William Harvey Research Foundation and by a grant from the University of Turin (Ricerca Locale ex-60% 2013). This work forms part of the research themes contributing to the translational research portfolio of Barts and the London Cardiovascular Biomedical Research Unit, which is supported and funded by the National Institute of Health Research. This work also contributes to the Organ Protection research theme of the Barts Centre for Trauma Sciences, supported by the Barts and The London Charity (Award 753/1722)
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ALMaQUEST. IV. The ALMA-MaNGA QUEnching and STar Formation (ALMaQUEST) Survey
The ALMaQUEST (ALMA-MaNGA QUEnching and STar formation) survey is a program
with spatially-resolved CO(1-0) measurements obtained with the Atacama
Large Millimeter Array (ALMA) for 46 galaxies selected from the Mapping Nearby
Galaxies at Apache Point Observatory (MaNGA) DR15 optical integral-field
spectroscopic survey. The aim of the ALMaQUEST survey is to investigate the
dependence of star formation activity on the cold molecular gas content at kpc
scales in nearby galaxies. The sample consists of galaxies spanning a wide
range in specific star formation rate (sSFR), including starburst (SB),
main-sequence (MS), and green valley (GV) galaxies. In this paper, we present
the sample selection and characteristics of the ALMA observations, and showcase
some of the key results enabled by the combination of spatially-matched stellar
populations and gas measurements. Considering the global (aperture-matched)
stellar mass, molecular gas mass, and star formation rate of the sample, we
find that the sSFR depends on both the star formation efficiency (SFE) and the
molecular gas fraction (), although the correlation with the
latter is slightly weaker. Furthermore, the dependence of sSFR on the molecular
gas content (SFE or ) is stronger than that on either the atomic
gas fraction or the molecular-to-atomic gas fraction, albeit with the small HI
sample size. On kpc scales, the variations in both SFE and
within individual galaxies can be as large as 1-2 dex thereby demonstrating
that the availability of spatially-resolved observations is essential to
understand the details of both star formation and quenching processes.STFC
ER
Comparison of coplanar and noncoplanar intensity-modulated radiation therapy and helical tomotherapy for hepatocellular carcinoma
<p>Abstract</p> <p>Background</p> <p>To compare the differences in dose-volume data among coplanar intensity modulated radiotherapy (IMRT), noncoplanar IMRT, and helical tomotherapy (HT) among patients with hepatocellular carcinoma (HCC) and portal vein thrombosis (PVT).</p> <p>Methods</p> <p>Nine patients with unresectable HCC and PVT underwent step and shoot coplanar IMRT with intent to deliver 46 - 54 Gy to the tumor and portal vein. The volume of liver received 30Gy was set to keep less than 30% of whole normal liver (V30 < 30%). The mean dose to at least one side of kidney was kept below 23 Gy, and 50 Gy as for stomach. The maximum dose was kept below 47 Gy for spinal cord. Several parameters including mean hepatic dose, percent volume of normal liver with radiation dose at X Gy (Vx), uniformity index, conformal index, and doses to organs at risk were evaluated from the dose-volume histogram.</p> <p>Results</p> <p>HT provided better uniformity for the planning-target volume dose coverage than both IMRT techniques. The noncoplanar IMRT technique reduces the V10 to normal liver with a statistically significant level as compared to HT. The constraints for the liver in the V30 for coplanar IMRT vs. noncoplanar IMRT vs. HT could be reconsidered as 21% vs. 17% vs. 17%, respectively. When delivering 50 Gy and 60-66 Gy to the tumor bed, the constraints of mean dose to the normal liver could be less than 20 Gy and 25 Gy, respectively.</p> <p>Conclusion</p> <p>Noncoplanar IMRT and HT are potential techniques of radiation therapy for HCC patients with PVT. Constraints for the liver in IMRT and HT could be stricter than for 3DCRT.</p
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The ALMaQUEST Survey. VII. Star Formation Scaling Relations of Green Valley Galaxies
We utilize the ALMA-MaNGA QUEnch and STar formation (ALMaQUEST) survey to
investigate the kpc-scale scaling relations, presented as the resolved star
forming main sequence (rSFMS: vs. ), the
resolved Schmidt-Kennicutt relation (rSK: vs. ), and the resolved molecular gas main sequence (rMGMS: vs. ), for 11478 star-forming and 1414 retired spaxels
(oversampled by a factor of ) located in 22 green valley (GV) and 12
main sequence (MS) galaxies. For a given galaxy type (MS or GV), the retired
spaxels are found to be offset from the sequences formed by the star-forming
spaxels on the rSFMS, rSK, and rMGMS planes, toward lower absolute values of
sSFR, SFE, and by 1.1, 0.6, and 0.5 dex. The scaling
relations for GV galaxies are found to be distinct from that of the MS
galaxies, even if the analyses are restricted to the star-forming spaxels only.
It is found that for star-forming spaxels, sSFR, SFE, and in GV
galaxies are reduced by 0.36, 0.14, and 0.21 dex, respectively, compared
to those in MS galaxies. Therefore, the suppressed sSFR/SFE/ in
GV galaxies are associated with not only an increased proportion of retired
regions in GV galaxies but also a depletion of these quantities in star-forming
regions. Finally, the reduction of SFE and in GV galaxies
relative to MS galaxies is seen in both bulge and disk regions (albeit with
larger uncertainties), suggesting that statistically, quenching in the GV
population may persist from the inner to the outer regions
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