1,906 research outputs found
Analyses of pion-nucleon elastic scattering amplitudes up to in extended-on-mass-shell subtraction scheme
We extend the analysis of elastic pion-nucleon scattering up to
level using extended-on-mass-shell subtraction scheme within the framework of
covariant baryon chiral perturbation theory. Numerical fits to partial wave
phase shift data up to GeV are performed to pin down the free
low energy constants. A good description to the existing phase shift data is
achieved. We find a good convergence for the chiral series at ,
considerably improved with respect to the -level analyses found in
previous literature. Also, the leading order contribution from explicit
resonance and partially-included loop
contribution are included to describe phase shift data up to
GeV. As phenomenological applications, we investigate chiral correction to the
Goldberger-Treiman relation % and find that it converges rapidly,
and the correction is found to be very small: . We also
get a reasonable prediction of pion-nucleon sigma term up to
by performing fits including both the pion-nucleon partial wave phase
shift data and the lattice QCD data. We report that MeV
from the fit without , and MeV from the
fit with explicit .Comment: The final version published in Phys.Rev. D 87, 054019 (2013
Characteristics of a micro-fin evaporator: Theoretical analysis and experimental verification
A theoretical analysis and experimental verification on the characteristics
of a micro-fin evaporator using R290 and R717 as refrigerants were carried
out. The heat capacity and heat transfer coefficient of the micro-fin
evaporator were investigated under different water mass flow rate, different
refrigerant mass flow rate, and different inner tube diameter of micro-fin
evaporator. The simulation results of the heat transfer coefficient are
fairly in good agreement with the experimental data. The results show that
heat capacity and the heat transfer coefficient of the micro-fin evaporator
increase with increasing logarithmic mean temperature difference, the water
mass flow rate and the refrigerant mass flow rate. Heat capacity of the
micro-fin evaporator for diameter 9.52 mm is higher than that of diameter
7.00 mm with using R290 as refrigerant. Heat capacity of the micro-fin
evaporator with using R717 as refrigerant is higher than that of R290 as
refrigerant. The results of this study can provide useful guidelines for
optimal design and operation of micro-fin evaporator in its present or future
applications
Hydrogen Generation from Al-NiCl2/NaBH4 Mixture Affected by Lanthanum Metal
The effect of La on Al/NaBH4 hydrolysis was elaborated in the present paper. Hydrogen generation amount increases but hydrogen generation rate decreases with La content increasing. There is an optimized composition that Al-15 wt% La-5 wt% NiCl2/NaBH4 mixture (Al-15 wt% La-5 wt% NiCl2/NaBH4 weight ratio, 1 : 3) has 126 mL g−1 min−1 maximum hydrogen generation rate and 1764 mL g−1 hydrogen generation amount within 60 min. The efficiency is 88%. Combined with NiCl2, La has great effect on NaBH4 hydrolysis but has little effect on Al hydrolysis. Increasing La content is helpful to decrease the particle size of Al-La-NiCl2 in the milling process, which induces that the hydrolysis byproduct Ni2B is highly distributed into Al(OH)3 and the catalytic reactivity of Ni2B/Al(OH)3 is increased therefore. But hydrolysis byproduct La(OH)3 deposits on Al surface and leads to some side effect. The Al-La-NiCl2/NaBH4 mixture has good stability in low temperature and its hydrolytic performance can be improved with increasing global temperature. Therefore, the mixture has good safety and can be applied as on board hydrogen generation material
Joint parameter optimization for perpetual nanonetworks and maximum network capacity
One of the major bottlenecks in nanonetworks is the very limited energy that can be accessed by nanodevices. To achieve perpetual data transmission, it is required to investigate in-depth the relationship between energy harvesting and consumption, and the underlying constraints in nanonetworks. In this paper, the tradeoff between energy harvesting and consumption is analyzed by considering the peculiarities of THz communication. First, based on the TS-OOK scheme and constrained energy in nanodevices, the upper bound of the transmitted pulse amplitude is presented. Second, given the proposed mathematical expression of the signal-to-interference-noise ratio (SINR) in multi-user nanonetworks, the lower bound of pulse amplitude is presented to satisfy the required SINR threshold. Third, the minimum spreading factor is derived to guarantee the perpetual nanonetworks by considering the energy harvesting-consumption tradeoff. Finally, the maximization of network capacity is investigated by jointly optimizing the parameters of spreading factor, transmission distance, amplitude of the transmitted pulse, pulse probability, and node density for perpetual nanonetworks. The simulation results demonstrate short transmission distance and small spreading factor are recommended to improve the network capacity. Moreover, pulse probability, pulse amplitude, spreading factor, and node density are required to be comprehensively manipulated to achieve the maximum network capacity and perpetual communication
Tuberculosis should not be ignored in patients with peripheral gangrene
Peripheral gangrene, characterized by distal ischemia of the extremities, is a rare complication in patients with tuberculosis (TB). We diagnosed a female patient with gangrene of her left toe caused by TB infection. She presented with fever, lymphadenectasis, and peripheral gangrene of the left toe. Lymph node biopsy confirmed tuberculous lymphadenitis and the computer tomography angiography showed vasculitis. The patient underwent antituberculous therapy and her condition was gradually improved. Although it is rare, TB should be considered as a possible cause of peripheral gangrene
Tetrakis(μ2-3,4-dimethoxyphenylacetato)-κ3 O,O′:O′;κ3 O:O:O′;κ2 O:O′;κ2 O:O′-bis[(3,4-dimethoxyphenylacetato-κ2 O,O′)(1,10-phenanthroline-κ2 N,N)thulium(III)]
In the title centrosymmetric dinuclear complex, [Tm2(C10H11O4)6(C12H8N2)2], the unique TmIII ion is coordinated by five 3,4-dimethoxyphenylacetate (DMPA) ligands and and a bis-chelating 1,10-phenanthroline (phen) ligand via seven O atoms and two N atoms, forming a distorted tricapped trigonal-prismatic environment. The DMPA ligands coordinate in the bis-chelate, bridging and bridging tridentate modes
Research in advance for FMD Novel Vaccines
Foot-and-Mouth Disease (FMD), as a major global animal disease, affects millions of animals worldwide and remains the main sanitary barrier to the international and national trade of animals and animal products. Inactivated vaccination is the most effective measure for prevention of FMD at present, but fail to induce long-term protection and content new requires for production of FMD vaccines. As a number of Researchers hope to obtain satisfactory novel vaccines by new bio-technology, novel vaccines have been studied for more than thirty years. Here reviews the latest research progress of new vaccines, summarizes some importance and raises several suggestions for the future of FMD vaccine
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