3,276 research outputs found
Interplay between Quantum Size Effect and Strain Effect on Growth of Nanoscale Metal Thin Film
We develop a theoretical framework to investigate the interplay between
quantum size effect (QSE) and strain effect on the stability of metal
nanofilms. The QSE and strain effect are shown to be coupled through the
concept of "quantum electronic stress. First-principles calculations reveal
large quantum oscillations in the surface stress of metal nanofilms as a
function of film thickness. This adds extrinsically additional strain-coupled
quantum oscillations to surface energy of strained metal nanofilms. Our theory
enables a quantitative estimation of the amount of strain in experimental
samples, and suggests strain be an important factor contributing to the
discrepancies between the existing theories and experiments
Effects of tidally enhanced stellar wind on the horizontal branch morphology of globular clusters
Metallicity is the first parameter to influence the horizontal branch (HB)
morphology of globular clusters (GCs). It has been found, however, that some
other parameters may also play an important role in affecting the morphology.
While the nature of these important parameters remains unclear, they are
believed to be likely correlated with wind mass-loss of red giants, since this
mass loss determines their subsequent locations on the HB. Unfortunately, the
mass loss during the red giant stages of the stellar evolution is poorly
understood at present. The stellar winds of red giants may be tidally enhanced
by companion stars if they are in binary systems. We investigate evolutionary
consequences of red giants in binaries by including tidally enhanced stellar
winds, and examine the effects on the HB morphology of GCs. We find that red,
blue, and extreme horizontal branch stars are all produced under the effects of
tidally enhanced stellar wind without any additional assumptions on the
mass-loss dispersion. Furthermore, the horizontal branch morphology is found to
be insensitive to the tidal enhancement parameter, Bw. We compare our
theoretical results with the observed horizontal branch morphology of globular
cluster NGC 2808, and find that the basic morphology of the horizontal branch
can be well reproduced. The number of blue horizontal branch stars in our
calculations, however, is lower than that of NGC 2808.Comment: 7 pages, 4 figures, 2 tables, accepted for publication in Astronomy &
Astrophysic
Bilateral congenital choanal atresia and osteoma of ethmoid sinus with supernumerary nostril: a case report and review of the literature
<p>Abstract</p> <p>Introduction</p> <p>Congenital choanal atresia is a relatively rare deformity, especially bilateral congenital choanal atresia. We report a case of bilateral congenital choanal atresia in a 22-year-old Chinese man, who was also diagnosed with congenital right accessory nasal deformity, osteoma of his left ethmoid sinus and congenital keratoleukoma of his right eye.</p> <p>Case presentation</p> <p>A 22-year-old Chinese man presented with mouth breathing, sleep snoring and difficult feeding after birth, with no olfactory sensation. Three-dimensional computed tomography revealed bilateral choanal atresia and a high density bony shadow in his left ethmoid sinus that extended to his left frontal sinus.</p> <p>Conclusions</p> <p>Choanal atresia is often accompanied by other congenital abnormalities. To the best of our knowledge, this is the first report of choanal atresia accompanied by congenital accessory nasal deformity and congenital keratoleukoma.</p
Effects of fully open-air [CO2] elevation on leaf photosynthesis and ultrastructure of Isatis indigotica Fort
Traditional Chinese medicine relies heavily on herbs, yet there is no information on how these herb plants would respond to climate change. In order to gain insight into such response, we studied the effect of elevated [CO2] on Isatis indigotica Fort, one of the most popular Chinese herb plants. The changes in leaf photosynthesis,chlorophyll fluorescence, leaf ultrastructure and biomass yield in response to elevated [CO2] (550619 mmol mol–1) were determined at the Free-Air Carbon dioxide Enrichment (FACE) experimental facility in North China. Photosynthetic ability of I. indigotica was improved under elevated [CO2]. Elevated [CO2] increased net photosynthetic rate (PN), water use efficiency (WUE) and maximum rate of electron transport (Jmax) of upper most fully-expended leaves, but not stomatal conductance (gs), transpiration ratio (Tr) and maximum velocity of carboxylation (Vc,max). Elevated [CO2] significantly increased leaf intrinsic efficiency of PSII (Fv’/Fm’) and quantum yield of PSII(WPSII), but decreased leaf non-photochemical quenching (NPQ), and did not affect leaf proportion of open PSII reaction centers (qP) and maximum quantum efficiency of PSII (Fv/Fm). The structural chloroplast membrane, grana layer and stroma thylakoid membranes were intact under elevated [CO2], though more starch grains were accumulated within the chloroplasts than that of under ambient [CO2]. While the yield of I. indigotica was higher due to the improved photosynthesis under elevated [CO2], the content of adenosine, one of the functional ingredients in indigowoad
root was not affected
catena-Poly[[{2-[(2-hydroxyethyl)iminomethyl]-6-methoxyphenolato}copper(II)]-μ-thiocyanato]
In the title thiocyanate-bridged polynuclear copper(II) complex, [Cu(C10H12NO3)(NCS)]n, the Cu atom is five-coordinated in a square-pyramidal geometry, with one phenolato O, one imino N and one hydroxy O atom of a Schiff base ligand and one thiocyanato N atom defining the basal plane, and with one thiocyanato S atom occupying the apical position. In the crystal structure, pairs of adjacent complex molecules are linked through intermolecular O—H⋯O hydrogen bonds into dimers. The dimers are further linked via Cu⋯S interactions, forming two-dimensional layers parallel to the bc plane
Stochastic bidding strategy of electric vehicles and energy storage systems in uncertain reserve market
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