552 research outputs found
An Analysis of Thickness-shear Vibrations of an Annular Plate with the Mindlin Plate Equations
The Mindlin plate equations with the consideration of thickness-shear
deformation as an independent variable have been used for the analysis of
vibrations of quartz crystal resonators of both rectangular and circular types.
The Mindlin or Lee plate theories that treat thickness-shear deformation as an
independent higher-order vibration mode in a coupled system of two-dimensional
variables are the choice of theory for analysis. For circular plates, we
derived the Mindlin plate equations in a systematic manner as demonstrated by
Mindlin and others and obtained the truncated two-dimensional equations of
closely coupled modes in polar coordinates. We simplified the equations for
vibration modes in the vicinity of fundamental thickness-shear frequency and
validated the equations and method. To explore newer structures of quartz
crystal resonators, we utilized the Mindlin plate equations for the analysis of
annular plates with fixed inner and free outer edges for frequency spectra. The
detailed analysis of vibrations of circular plates for the normalized frequency
versus dimensional parameters provide references for optimal selection of
parameters based on the principle of strong thickness-shear mode and minimal
presence of other modes to enhance energy trapping through maintaining the
strong and pure thickness-shear vibrations insensitive to some complication
factors such as thermal and initial stresses.Comment: Paper to be presented to the 2015 IEEE International Frequency
Control Symposium and European Frequency and Time Forum, Denver, CO, USA.
April 12-16, 201
Density functional study of FeS, FeSe and FeTe: Electronic structure, magnetism, phonons and superconductivity
We report density functional calculations of the electronic structure, Fermi
surface, phonon spectrum, magnetism and electron-phonon coupling for the
superconducting phase FeSe, as well as the related compounds FeS and FeTe. We
find that the Fermi surface structure of these compounds is very similar to
that of the Fe-As based superconductors, with cylindrical electron sections at
the zone corner, cylindrical hole surface sections, and depending on the
compound, other small hole sections at the zone center. As in the Fe-As based
materials, these surfaces are separated by a 2D nesting vector at
(,). The density of states, nesting and Fermi surface size increase
going from FeSe to FeTe. Both FeSe and FeTe show spin density wave ground
states, while FeS is close to an instability. In a scenario where
superconductivity is mediated by spin fluctuations at the SDW nesting vector,
the strongest superconductor in this series would be doped FeTe.Comment: Added note regarding recent experimental observations of
superconductivity under pressure. Some additional discussio
Density Functional Study of Excess Fe in FeTe: Magnetism and Doping
The electronic and magnetic properties of the excess Fe in iron telluride
FeTe are investigated by density functional calculations. We find
that the excess Fe occurs with valence near Fe, and therefore provides
electron doping with approximately one carrier per Fe, and furthermore that the
excess Fe is strongly magnetic. Thus it will provide local moments that
interact with the plane Fe magnetism, and these are expected to persist in
phases where the magnetism of the planes is destroyed for example by pressure
or doping. These results are discussed in the context of superconductivity
A FARM-TO-DOOR DELIVERY MODE FOR ORGANIC VEGETABLES UNDER MOBILE COMMERCE IN METROPOLISES OF CHINA
This paper presents a farm-to-door delivery mode for organic vegetables, which connects farmers and customers directly, under the circumstance of mobile commerce (M-commerce). In recent years, the need of organic vegetables is growing constantly in China. Meanwhile, the farm-to-door delivery mode widely spread in metropolises as people there barely have time to go to food markets on weekdays. However, the terrible traffic condition makes it impossible to conduct the delivery in day time. So vegetables have to be delivered very early in the morning (usually 3:00-7:00 A.M.), which makes the owner unable to attend delivery. And in the traditional delivery mode, the absence of delivery may lead to the package missing in China. Aiming at solving these practical issues in China, an SMS-based interaction system is integrated in the delivery mode for informing, endorsing, confirming, tracing and complaining. Intelligent cupboards are used as a buffer to realize the asynchronously endorsement. This is a new business mode that extends the frontiers of the M-commerce. It can greatly reduce the intermediate links of vegetable distribution and simplify the food purchasing in people’s daily life. This application of mobile technology would have a huge potential in market
Ananas comosus
In this study, we aimed to investigate the effect and action mechanisms of pineapple leaf phenols (PLPs) on liver fat metabolism in high-fat diet-fed mice. Results show that PLP significantly reduced abdominal fat and liver lipid accumulation in high-fat diet-fed mice. The effects of PLP were comparable with those of FB. Furthermore, at the protein level, PLP upregulated the expression of carnitine palmitoyltransferase 1 (CPT-1), whereas FB had no effects on CPT-1 compared with the HFD controls. Regarding mRNA expression, PLP mainly promoted the expression of CPT-1, PGC1a, UCP-1, and AMPK in the mitochondria, whereas FB mostly enhanced the expression of Ech1, Acox1, Acaa1, and Ehhadh in peroxisomes. PLP seemed to enhance fat metabolism in the mitochondria, whereas FB mainly exerted the effect in peroxisomes. In addition, p-coumaric acid (CA), one of the main components from PLP, significantly inhibited fat accumulation in oleic acid-induced HepG2 cells. CA also significantly upregulated CPT-1 mRNA and protein expressions in HepG2 cells. We, firstly, found that PLP enhanced liver fat metabolism by upregulating CPT-1 expression in the mitochondria and might be promising in treatment of fatty liver diseases as alternative natural products. CA may be one of the active components of PLP
Scorpion in Combination with Gypsum: Novel Antidiabetic Activities in Streptozotocin-Induced Diabetic Mice by Up-Regulating Pancreatic PPARγ and PDX-1 Expressions
The management of diabetes without any side effects remains a challenge in medicine. In this study, antidiabetic activity and the mechanism of action of scorpion combined with gypsum (SG) were investigated. Streptozotocin-induced diabetic mice were orally administrated with scorpion (200 mg kg−1 per day) in combination with gypsum (200 mg kg−1 per day) for 5 weeks. SG treatment resulted in decreased body weight, blood glucose and lipid levels, and increased serum and pancreatic insulin levels in diabetic mice. Furthermore, SG significantly increased the number and volume of beta cells in the Islets of Langerhans and promoted peroxisome proliferator-activated receptor gamma and pancreatic duodenal homeobox 1 expressions in pancreatic tissues. However, scorpion or gypsum alone had no significant effect in this animal model. Metformin showed a slight or moderate effect in this diabetic model, but this effect was weak compared with that of SG. Taken together, SG showed a new antidiabetic effect in streptozotocin-induced diabetic mice. This effect may possibly be involved in enhancing beta-cell regeneration and promoting insulin secretion by targeting PPARγ and PDX-1. Moreover, this new effect of SG offers a promising step toward the treatment of diabetic patients with beta-cell failure as a complementary and alternative medicine
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