5,691 research outputs found
On the characteristics of emulsion chamber family events produced in low heights
The uncertainty of the primary cosmic ray composition at 10 to the 14th power -10 to the 16th power eV is well known to make the study of the nuclear interaction mechanism more difficult. Experimentally considering, if one can identify effectively the family events which are produced in low heights, then an event sample induced by primary protons might be able to be separated. It is undoubtedly very meaningful. In this paper an attempt is made to simulate the family events under the condition of mountain emulsion chamber experiments with a reasonable model. The aim is to search for the dependence of some experimentally observable quantities to the interaction height
Effects of polysaccharide from Lycium barbarum in alloxan-induced diabetic mice
A study was undertaken to evaluate the effects of polysaccharide from Lycium barbarum (LBP) in alloxan-induced diabetic mice. The various parameters studied included body weight, fasting blood glucose levels, total cholesterol (TC) and triglyceride (TG) in diabetic and normal mice. LBP treatment(20, 40 mg/ kg body weight) for 28 days resulted in a significant decrease in the concentration of fasting blood glucose (FBG), total cholesterol (TC) and triglyceride (TG) in diabetes mellitus mice. Furthermore, LBP significantly increased body weight (bw). The data demonstrated LBP at the dose of 40 mg/kg bw exhibited the optimal effect
PSR J1953+1844 probably being the descendant of an Ultra-compact X-ray binary
PSR J1953+1844 (i.e., M71E) is a millisecond pulsar (MSP)in a 53 minute
binary orbit discovered by the Five-hundred-meter Aperture Spherical radio
Telescope. The mass function from pulsar timing is
. The possible redback origin of this system has been discussed by Pan
et al. We discuss here an alternative evolution track for this binary system,
namely that PSR J1953+1844 is a descendant of an ultra-compact X-ray binary
(UCXB), which has a hydrogen-poor donor accreting onto a neutron star (NS) with
an orbital period of hr. We noticed that some of UCXB systems hold an
accreting millisecond X-ray pulsars (AMXPs) and a donor with a mass of about
0.01 M. M71E has a very similar orbit to those of AMXPs, indicating
that it might be evolved from a UCXB similar to PSR J1653--0158. The companion
star of M71E should be significantly bloated and it most probably has a carbon
and oxygen composition, otherwise a low inclination angle of the orbit is
required for a helium companion. The discovery of this M71E binary system may
shed light on when and how an NS in a UCXBs turns into a radio pulsar.Comment: Accepted for publication in ApJL. 5 pages, 2 figure
Geometric entanglement from matrix product state representations
An efficient scheme to compute the geometric entanglement per lattice site
for quantum many-body systems on a periodic finite-size chain is proposed in
the context of a tensor network algorithm based on the matrix product state
representations. It is systematically tested for three prototypical critical
quantum spin chains, which belong to the same Ising universality class. The
simulation results lend strong support to the previous claim [Q.-Q. Shi, R.
Or\'{u}s, J. O. Fj{\ae}restad, and H.-Q. Zhou, New J. Phys \textbf{12}, 025008
(2010); J.-M. St\'{e}phan, G. Misguich, and F. Alet, Phys. Rev. B \textbf{82},
180406R (2010)] that the leading finite-size correction to the geometric
entanglement per lattice site is universal, with its remarkable connection to
the celebrated Affleck-Ludwig boundary entropy corresponding to a conformally
invariant boundary condition.Comment: 4+ pages, 3 figure
Real Scalar Field Scattering with Polynomial Approximation around Schwarzschild-de Sitter Black-hole
As one of the fitting methods, the polynomial approximation is effective to
process sophisticated problem. In this paper, we employ this approach to handle
the scattering of scalar field around the Schwarzschild-de Sitter black-hole.
The complex relationship between tortoise coordinate and radial coordinate is
replaced by the approximate polynomial. The Schrdinger-like equation,
the real boundary conditions and the polynomial approximation construct a full
Sturm-Liouville type problem. Then this boundary value problem can be solved
numerically according to two limiting cases: the first one is the Nariai
black-hole whose horizons are close to each other, the second one is when the
horizons are widely separated. Compared with previous results (Brevik and
Tian), the field near the event horizon and cosmological horizon can have a
better description.Comment: revtex4 source file, 11 pages, 8 figure
Summer Upwelling in the Northern Continental Shelf of the South China Sea
Summer upwelling system in the northern continental shelf of the South China Sea (NCSCS) is investigated with the Pathfinder, Advanced Very High Resolution Radiometer (AVHRR) Sea Surface Temperature (SST), and a three-dimensional, baroclinic, non-linear, numerical model forced by QuikSCAT winds. The AVHRR observation and modelling results have shown the upwelling is a regular phenomenon during summer in the NCSCS. Continental shelf upwelling characteristics are clearly found in the surface and subsurface water, such as low temperature, high salinity and high potential density. They respectively locate in the east of the Hainan Island, the east of the Leizhou Peninsula and the southeast of the Zhanjiang Bay (Qiongdong Upwelling), and the inshore areas from the Shantou Coast to the Nanri Islands of Fujian Coast (Yuedong Upwelling). The centra of the upwelling are mostly located in 111°10â˛Eă19°45â˛N between the Qinglan Bay and the Qizhou Archipelagoes of eastern Hainan Island, 110°15â˛Eă18°25â˛N near the Lingshui Bay, 116°45â˛Eă22°50â˛N of the Shantou Coast and 118°Eă23°40â˛N near the Taiwan Shoal. It is also found that the upwelling areas and centra from modelling results are in agreement with the AVHRR SST
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Compositionally Graded OrganicâInorganic Nanocomposites for Enhanced Thermoelectric Performance
AbstractThermoelectric generators (TEGs) operate in the presence of a temperature gradient, where the constituent thermoelectric (TE) material converts heat into electricity via the Seebeck effect. However, TE materials are characterized by a thermoelectric figure of merit (ZT) and/or power factor (PF), which often has a strong dependence on temperature. Thus, a single TE material spanning a given temperature range is unlikely to have an optimal ZT or PF across the entire range, leading to inefficient TEG performance. Compositionally graded organicâinorganic nanocomposites are demonstrated, where the composition of the TE nanocomposite can be systematically tuned along the length of the TEG, in order to optimize the PF along the applied temperature gradient. The nanocomposite composition is dynamically tuned by an aerosolâjet printing method with controlled in situ mixing capability, thus enabling the realization of such compositionally graded thermoelectric composites (CGâTECs). It is shown how CGâTECs can be realized by varying the loading weight percentage of Bi2Te3 nanoparticles or Sb2Te3 nanoflakes within an organic conducting matrix using bespoke solutionâprocessable inks. The enhanced energy harvesting capability of these CGâTECs from lowâgrade waste heat (<100 °C) is demonstrated, highlighting the improvement in output power over singleâcomponent TEGs.</jats:p
Magnetic properties of undoped Cu2O fine powders with magnetic impurities and/or cation vacancies
Fine powders of micron- and submicron-sized particles of undoped Cu2O
semiconductor, with three different sizes and morphologies have been
synthesized by different chemical processes. These samples include nanospheres
200 nm in diameter, octahedra of size 1 micron, and polyhedra of size 800 nm.
They exhibit a wide spectrum of magnetic properties. At low temperature, T = 5
K, the octahedron sample is diamagnetic. The nanosphere is paramagnetic. The
other two polyhedron samples synthesized in different runs by the same process
are found to show different magnetic properties. One of them exhibits weak
ferromagnetism with T_C = 455 K and saturation magnetization, M_S = 0.19 emu/g
at T = 5 K, while the other is paramagnetic. The total magnetic moment
estimated from the detected impurity concentration of Fe, Co, and Ni, is too
small to account for the observed magnetism by one to two orders of magnitude.
Calculations by the density functional theory (DFT) reveal that cation
vacancies in the Cu2O lattice are one of the possible causes of induced
magnetic moments. The results further predict that the defect-induced magnetic
moments favour a ferromagnetically coupled ground state if the local
concentration of cation vacancies, n_C, exceeds 12.5%. This offers a possible
scenario to explain the observed magnetic properties. The limitations of the
investigations in the present work, in particular in the theoretical
calculations, are discussed and possible areas for further study are suggested.Comment: 20 pages, 5 figures 2 tables, submitted to J Phys Condense Matte
Virtual medical plant modeling based on L-system
Background: Searching the drug molecules from the medicinal plants become more and more popular given that herbalcomponents have been widely considered to be safe. In medical virtual plant studies, development rules are difficult to be extracted, the construction of plant organs is highly dependent on equipment and the process is complicated.Aim: To establish three-dimensional structural virtual plant growth model.Methods: The quasi-binary tree structure and its properties were obtained through the research of theory on binary tree, then the relationship between quasi-binary tree structure and plant three-dimensional branching structure model was analyzed, and the three-dimensional morphology of plants was described.Results: A three-dimensional plant branch structure pattern extracting algorithm based on quasi-binary tree structure. By using 3-D L-system method, the extracted rules were systematized, and standardized. Further more, we built a comprehensive L-model system. With the aid of graphics and PlantVR, we implemented the plant shape and 3-D structureâs reconstruction.Conclusion: Three-dimensional structure virtual plant growth model based on time- controlled L-system has been successfully established.Keywords: Drug R&D, toxicity, medical plants, fractals; L-system; quasi binary-trees
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