http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Nuclear Data Uncertainties in 2010: A Perspective
D. L. Smith 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
Six years have passed since the International Conference on Nuclear Data forScience and Technology held in Santa Fe, New Mexico, U.S.A., 2004 (ND-2004)where this author presented a similar invited paper. The present paperdiscusses the progress made since 2004 in the production of covarianceevaluations and their usage in applications. It also points out thechallenges ahead for the nuclear science community in this field. The pathto be be followed during the next several years in this field is fairlyclear, but several barriers need to be overcome along the way. Among theseare resource limitations (funding and manpower), constraints of existingnuclear data formats, applications code shortcomings, and the need toeducate experimenters on how to properly quantify and report uncertaintiesin their measured data. These barriers are not insurmountable, but thenuclear data and applications communities need to give thoughtfulconsideration to setting priorities and making the technical choices thatwill impact the work of an entire generation of applied nuclear researchers.
Coupled double-row formation in a quasi-1D wire
Smith, L.W.,Hew, W.K.,Thomas, K.J.,Pepper, M.,Farrer, I.,Anderson, D.,Jones, G.A.C.,Ritchie, D.A. North-Holland 2010 Physica E, Low-dimensional systems & nanostructure Vol.42 No.4
We investigate one-dimensional (1D) quantum wires in the weak confinement regime, where, at certain densities, the 1D system of electrons bifurcates into two rows. We show that the two rows are coupled, forming bonding and antibonding states, and that the coupling persists in magnetic fields from 0 to 16 T. In order for a double row to form, the Coulomb interactions in the channel must overcome the confining potential, which can be achieved by tuning the density and confinement. Using a split-gate device with a top gate and back gate, we observe a transition from single-row to double-row behaviour in the weak confinement regime. We further probe the characteristics of the coupled double row regime with dc source-drain bias measurements.
LEGACY EXTRAGALACTIC UV SURVEY (LEGUS) WITH THE<i>HUBBLE SPACE TELESCOPE</i>. I. SURVEY DESCRIPTION
Calzetti, D.,Lee, J. C.,Sabbi, E.,Adamo, A.,Smith, L. J.,Andrews, J. E.,Ubeda, L.,Bright, S. N.,Thilker, D.,Aloisi, A.,Brown, T. M.,Chandar, R.,Christian, C.,Cignoni, M.,Clayton, G. C.,Silva, R. da,Mi IOP Publishing 2015 The Astronomical journal Vol.149 No.2
Searching for Resonances in the Unbound 6Be Nucleus by Using a Radioactive 7Be Beam
채경육,D. W. Bardayan,J. C. Blackmon,M. S. Smith,A. E. Champagne,J. J. Das,R. P. Fitzgerald,D. W. Visser,V. Guimaraes,K. L. Jones,S. D. Pain,J. S. Thomas,M. S. Johnson,R. L. Kozub,R. J. Livesay,Z. Ma,C. 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.11
Knowledge of the <sup>3</sup>He(<sup>3</sup>He,<sup>2</sup><i>p</i>)<sup>4</sup>He reaction is important for understanding stellar burning and solar neutrino production. Previous measurements have found a surprisingly large rise in the cross section at low energies that could be due to a low-energy resonance in the <sup>3</sup>He + <sup>3</sup>He (<sup>6</sup>Be) system or electron screening. In the <sup>6</sup>Be nucleus, however, no excited states have been observed above the first 2<sup>+</sup> state at <i>E<sub>x</sub></i> = 1.67 MeV up to 23 MeV, even though several are expected. The <sup>2</sup>H(<sup>7</sup>Be,<sup>3</sup>H)<sup>6</sup>Be reaction has been studied for the first time to search for resonances in the <sup>6</sup>Be nucleus that may affect our understanding of the <sup>3</sup>He(<sup>3</sup>He,<sup>2</sup><i>p,</i>)<sup>4</sup>He reaction. A 100-MeV radioactive <sup>7</sup>Be beam from the Holifield Radioactive Ion Beam Facility (HRIBF) was used to bombard CD<sub>2</sub> targets, and tritons were detected by using the silicon detector array (SIDAR). A combination of reaction mechanisms appears to be necessary to explain the observed triton energy spectrum.
THE BRIGHTEST YOUNG STAR CLUSTERS IN NGC 5253
Calzetti, D.,Johnson, K. E.,Adamo, A.,Gallagher III, J. S.,Andrews, J. E.,Smith, L. J.,Clayton, G. C.,Lee, J. C.,Sabbi, E.,Ubeda, L.,Kim, H.,Ryon, J. E.,Thilker, D.,Bright, S. N.,Zackrisson, E.,Kennic IOP Publishing 2015 The Astrophysical journal Vol.811 No.2
<P>The nearby dwarf starburst galaxy NGC 5253 hosts a number of young, massive star clusters, the two youngest of which are centrally concentrated and surrounded by thermal radio emission (the 'radio nebula'). To investigate the role of these clusters in the starburst energetics, we combine new and archival Hubble Space Telescope images of NGC 5253 with wavelength coverage from 1500 angstrom 1.9 mu m in 13 filters. These include H alpha, P beta, and P alpha, and the imaging from the Hubble Treasury Program LEGUS (Legacy Extragalactic UV Survey). The extraordinarily well-sampled spectral energy distributions enable modeling with unprecedented accuracy the ages, masses, and extinctions of the nine optically brightest clusters (M-V < -8.8) and the two young radio nebula clusters. The clusters have ages similar to 1-15 Myr and masses similar to 1 x 10(4)-2.5 x 10(5) M-circle dot. The clusters' spatial location and ages indicate that star formation has become more concentrated toward the radio nebula over the last similar to 15 Myr. The most massive cluster is in the radio nebula; with a mass similar to 2.5 x 10(5) M-circle dot and an age similar to 1 Myr, it is 2-4 times less massive and younger than previously estimated. It is within a dust cloud with AV similar to 50 mag, and shows a clear near-IR excess, likely from hot dust. The second radio nebula cluster is also similar to 1 Myr old, confirming the extreme youth of the starburst region. These two clusters account for about half of the ionizing photon rate in the radio nebula, and will eventually supply about 2/3 of the mechanical energy in present-day shocks. Additional sources are required to supply the remaining ionizing radiation, and may include very massive stars.</P>
High-speed X-ray Imaging of Pressurized Metered-dose Inhaler Sprays with Variable Ethanol Content
( N. Mason-smith ),( D. J. Duke ),( A. L. Kastengren ),( D. Edgington-mitchell ),( D. R. Honnery ) 한국액체미립화학회 2017 한국액체미립화학회 학술강연회 논문집 Vol.2017 No.-
Pressurised metered-dose inhalers discharge a fixed volume of a drug-containing hydrofluoroalkane propellant, resulting in a transient multiphase flow that is atomised and transported into the users’ respiratory system. Cosolvents such as ethanol are added to the propellant in solution pMDIs to aid with drug solubility. We investigate the internal and near-nozzle flows of metered flashing sprays from pressurised metered-dose inhalers. Seven formulations were studied, comprising R134a or R227ea propellant with varying concentrations of ethanol cosolvent. High speed x-ray phase contrast imaging was performed at the 7-ID beamline of the Advanced Photon Source at Argonne National Laboratory. The images obtained reveal the internal flow structures, providing visualisations of the multiphase flows formed inside the metering and expansion chambers and nozzle. At start of injection, vapour forms immediately--large bubbles appear in the metering chamber, and are transported through the valve orifice. For propellant-only cases, the expansion chamber flow contains a wall-bounded liquid annulus with a vaporous core. At moderate ethanol concentrations, its inclusion alters the internal flow structure. The presence of ethanol raises the mixture surface tension, which can inhibit bubble coalescence, and introduces surface tension gradients and resulting Marangoni stresses. At low concentrations, ethanol’s inclusion has little apparent effect. Propellant-only flows display occasional discharge of large liquid masses that are expected to be poorly atomized. The potential for addition of nonvolatiles to flashing and effervescent sprays as a means of controlling atomisation quality is discussed.
Chae, K.Y.,Ahn, S.,Ayres, A.,Bardayan, D.W.,Bey, A.,Greife, U.,Howard, M.E.,Jones, K.L.,Kozub, R.L.,Matoš,, M.,Moazen, B.H.,Nesaraja, C.D.,O’Malley, P.D.,Peters, W.A.,Pittman, S.T.,Smith, M.S. Elsevier 2018 Nuclear Instruments & Methods in Physics Research. Vol.900 No.-
<P><B>Abstract</B></P> <P>Direct measurements of ( α , p ) reactions of astrophysical interest with radioactive beams presents serious challenges because of the difficult nature of helium targets and the typical low intensities of the beams. To address this, a new technique has been developed for measurements of low-energy ( α , p ) reactions with heavy ion beams using an extended <SUP> 4 </SUP> He gas target and a newly developed gas recirculating system. The system was used to measure the <SUP> 4 </SUP> He(<SUP>19</SUP>F, <SUP> 1 </SUP> H)<SUP>22</SUP>Ne reaction as a demonstration. Excitation functions of the <SUP>19</SUP>F( α , p )<SUP>22</SUP>Ne and <SUP>19</SUP>F( α , <SUP> p ′ </SUP> )<SUP>22</SUP>Ne <SUP> ∗ </SUP> reactions were successfully measured to show the viability of this technique. Details of the approach and future plans are given.</P>
Smith, S. B.,Go, G. W.,Johnson, B. J.,Chung, K. Y.,Choi, S. H.,Sawyer, J. E.,Silvey, D.T.,Gilmore, L. A.,Ghahramany, G.,Kim, K. H. Oxford University Press 2012 Journal of animal science Vol.90 No.8
<P>We have demonstrated that among carcass adipose tissue depots, brisket subcutaneous adipose tissue contains the greatest concentration of MUFA and lowest concentration of SFA. Therefore, we hypothesized that brisket subcutaneous adipose tissue depots would exhibit greater adipogenic gene expression over time than other major subcutaneous adipose tissue depots. Four Angus steers, each at 9, 12, 14, and 16 mo of age, were harvested and fresh subcutaneous adipose tissue samples were collected from over the brisket, chuck, rib, loin, sirloin, round, flank, and plate. Relative gene expression for C/EBPβ, PPARγ, carnitine palmitoyltransferase-1 beta (CPT-1β), stearoyl-coenzyme A desaturase (SCD), AMP-activated protein kinase alpha (AMPKα), and G-coupled protein receptor 43 (GPR43) was analyzed by quantitative real-time PCR. Expression of C/EBPβ, PPARγ, and CPT-1β was greatest at 12 to 14 mo of age (all P < 0.0001) and declined to very low abundance by 16 mo of age in all depots. Expression of PPARγ and CPT-1β was greater (P < 0.03) in flank, rib, and sirloin subcutaneous adipose tissues than in brisket and round adipose tissues. The expression of the SCD gene did not differ among the 4 age groups (P = 0.95). The palmitoleic:stearic acid ratio (an estimate of SCD activity) was greater (P < 0.001) in the subcutaneous adipose tissues from brisket, plate, and round than in the loin, rib, and sirloin. Conversely, subcutaneous adipose tissue from the loin, rib, and sirloin had greater (P < 0.001) SCD gene expression than the brisket, plate, and round. In general, subcutaneous adipose tissues with the highest concentration of MUFA and least SFA consistently exhibited the least SCD gene expression and adipogenic gene expression. We conclude that MUFA in the brisket and other depots with large SCD indices were deposited before 9 mo of age, during a time when the subcutaneous adipocytes were highly differentiated.</P>
Modulation of Quantum Well Optical Properties by Illumination above the Barrier Bandgap
D. Wolverson,A. V. Koudinov,Yu. G. Kusrayev,L. C. Smith,J. J. Davies,M. Wiater,G. Karczewski,T. Wojtowicz 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5
The spin flip Raman scattering signals associated with the Mn2+ 3d5 electrons in a range of CdTe-based dilute magnetic semiconductor quantum well structures is shown to be sensitive to even very weak above-barrier illumination, as are the quantum-well photoluminescence from exciton and trion recombination and acoustic phonon Raman scattering signals excited in resonance with the quantum well. This surprising degree of sensitivity is discussed in terms of the modulation of the carrier densities in the quantum wells, leading to a modulation of the resonant intermediate state for Raman scattering and, therefore, of the scattering cross section. Depending on the majority intrinsic carrier type in the quantum wells, we show that either enhancing or quenching of the Raman signals can result.