6,662 research outputs found
QCD corrections to the R-parity violating processes at hadron colliders
We present the QCD corrections to the processes at
the Tevatron and the CERN large hadron collider(LHC). The numerical results
show that variation of K factor is in the range between and
at the Tevatron(LHC). We find that the QCD correction part from
the one-loop gluon-gluon fusion subprocess is remarkable at the LHC and should
be taken into account.Comment: 7 pages, 6 Postscript figures, to be appeared in Phy. Rev.
Exploring the interfacial coupling between graphene and the antiferromagnetic insulator MnPSe
Interfacial coupling between graphene and other 2D materials can give rise to
intriguing physical phenomena. In particular, several theoretical studies
predict that the interplay between graphene and an antiferromagnetic insulator
could lead to the emergence of quantum anomalous Hall phases. However, such
phases have not been observed experimentally yet, and further experimental
studies are needed to reveal the interaction between graphene and
antiferromagnetic insulators. Here, we report the study in heterostructures
composed of graphene and the antiferromagnetic insulator MnPSe. It is found
that the MnPSe has little impact on the quantum Hall phases apart from
doping graphene via interfacial charge transfer. However, the magnetic order
can contribute indirectly via process like Kondo effect, as evidenced by the
observed minimum in the temperature-resistance curve between 20-40 K, far below
the N\'eel temperature (70 K)
Inflammatory responses to Hydroxyapatite implants in middle ear in rats
AbstractObjectiveTo study local inflammatory response after implantation of hydroxyapatite synthetic ossicular prosthesis.MethodsHydroxyapatite granules were implanted in the bulla in 32 rats. Sham surgical procedures were performed in 10 rats as the control. Animals were sacrificed at 1 to 300 days after surgery. Bulla sections, stained with HE and Mallory’s azan, were examined for numbers and percentages of various inflammatory cell types.ResultsSlightly more inflammatory reaction was seen in animals with the implant than in the controls, mostly during the early stage following the implantation procedure. Few inflammatory cells were observed at later times. There were satisfactory fibrosis in both implanted and control ears.ConclusionThe results indicate that hydroxyapatite synthetic prosthesis is a biocompatible implantation material in the middle ear. Nonetheless, the presence of inflammatory reaction immediately following implantation implies that control of infection is important in the early times after the implantation procedure
Simultaneous determination of aconitum alkaloids in rat body fluids by high-performance liquid chromatography
A sensitive, reliable and accurate high-performance liquid chromatography (HPLC) method coupled with photodiode array detector (DAD) were developed for the simultaneous quantitative determination of aconitine, mesaconitine and hypaconitine in rat plasma and urine by optimizing the extraction, separation and analytical conditions. The analyses were chromatographed on a ZORBAX Eclipse XDB-C18 column (150 mm ~ 4.6 mm i.d.; 5 ƒÊm particle size) with gradient elution using solvents ofacetonitrile and ammonium acetate buffer (pH 10.0). The detection wavelength was 240 nm. Intra-assay and inter-assay precision of the analyses were less than 10% and the average recovery rates obtainedwere in the range of 85.63 - 90.94% for all analysis of the three aconitum alkaloids with relative standard deviations (RSD) below 14%. Positive linear relationships were observed in correlation coefficients that exceeded 0.95. The limits of detection (signal-to-noise ratio of 3) were 2.64, 1.58 and 2.75 ng for aconitine, mesaconitine and hypaconitine, respectively. The method can provide a scientific and technical platform to determine the concentration of aconitum alkaloids in plasma during a pilot pharmacokinetic study in rats
When Online Auction Meets Virtual Reality: An Empirical Investigation
The online auction is becoming increasingly popular in e-commerce, which allows to sell a product to the buyer with the highest bid. However, the lack of authentic product details for a thorough evaluation still poses challenges to its success. Recently, virtual reality (VR) is introduced to online auctions. We employ a unique dataset to investigate the effects of VR on auction outcomes and bidding activities. Results show that VR enhances buyers’ bidding competition, which in turn increases auction success and price, resulting in a competitive effect. Additionally, we find VR boosts buyers’ strategic responses to the bidding war, leading to a late-bidding effect. Findings contribute to both the theory and practice of VR and online auctions in selling houses
Research on bearing radiation noise and optimization design based on coupled vibro-acoustic method
For bearings, radiation noise was an important evaluation index for mechanical property, in particularly mute machinery. Environmental pollution caused by bearing noise has always been the focus in bearing industry. In this paper, slippage of the rolling bearing and its own variable stiffness excitation were considered to accomplish the vibration coupling between the bearing and bearing seat as well as the coupling between bearing vibration and noise by means of combination of dynamic model, FEA model and boundary element method. A perfect coupled vibro-acoustic model of the bearing was built, and its results were compared with the experimental results to verify the reliability of the proposed method. Based on the verified simulation model, the improved design was carried out for the low-noise rolling bearings. Finally, in order to further verify the superiority of the proposed method in this paper, the designed rolling bearing was compared with that of the traditional design method. The results showed that the proposed design method was reliable
3D Radiation Hydrodynamic Simulations of Gravitational Instability in AGN Accretion Disks: Effects of Radiation Pressure
We perform 3D radiation hydrodynamic local shearing box simulations to study
the outcome of gravitational instability (GI) in optically thick Active
Galactic Nuclei (AGN) accretion disks. GI develops when the Toomre parameter QT
\leq 1, and may lead to turbulent heating that balances radiative cooling.
However, when radiative cooling is too efficient, the disk may undergo runaway
gravitational fragmentation. In the fully gas-pressure-dominated case, we
confirm the classical result that such a thermal balance holds when the
Shakura-Sunyaev viscosity parameter (alpha) due to the gravitationally-driven
turbulence is \sim 0.2, corresponding to dimensionless cooling times Omega
tcool \sim 5. As the fraction of support by radiation pressure increases, the
disk becomes more prone to fragmentation, with a reduced (increased) critical
value of alpha (omega tcool). The effect is already significant when the
radiation pressure exceeds 10% of the gas pressure, while fully
radiation-pressure-dominated disks fragment at Omega tcool <50 . The latter
translates to a maximum turbulence level alpha<0.02, comparable to that
generated by Magnetorotational Instability (MRI). Our results suggest that
gravitationally unstable (QT \sim 1) outer regions of AGN disks with
significant radiation pressure (likely for high/near- Eddington accretion
rates) should always fragment into stars, and perhaps black holes.Comment: 26 pages, 19 figures, ApJ in Pres
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