| 1. |
- Abulaiti, Yiming, et al.
(författare)
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Search for the Standard Model Higgs boson produced by vector-boson fusion and decaying to bottom quarks in root s=8TeV pp collisions with the ATLAS detector
- 2016
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; :11
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Tidskriftsartikel (refereegranskat)abstract
- A search with the ATLAS detector is presented for the Standard Model Higgs boson produced by vector-boson fusion and decaying to a pair of bottom quarks, using 20.2 fb(-1) of LHC proton-proton collision data at root s - 8 TeV. The signal is searched for as a resonance in the invariant mass distribution of a pair of jets containing b-hadrons in vector-boson-fusion candidate events. The yield is measured to be -0.8 +/- 2.3 times the Standard Model cross-section for a Higgs boson mass of 125 GeV. The upper limit on the cross-section times the branching ratio is found to be 4.4 times the Standard Model cross-section at the 95% confidence level, consistent with the expected limit value of 5.4 (5.7) in the background-only (Standard Model production) hypothesis.
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| 2. |
- Andersson, Erik, et al.
(författare)
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Ambio fit for the 2020s
- 2022
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Ingår i: Ambio. - : Springer Nature. - 0044-7447 .- 1654-7209. ; 51:5, s. 1091-1093
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Castleton, Christopher, 1969-, et al.
(författare)
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Managing the supercell approximation for charged defects in semiconductors : Finite-size scaling, charge correction factors, the band-gap problem, and the ab initio dielectric constant
- 2006
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 73:035215, s. 11-
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Tidskriftsartikel (refereegranskat)abstract
- The errors arising in ab initio density functional theory studies of semiconductor point defects using the supercell approximation are analyzed. It is demonstrated that (a) the leading finite size errors are inverse linear and inverse cubic in the supercell size and (b) finite size scaling over a series of supercells gives reliable isolated charged defect formation energies to around +-0.05 eV. The scaled results are used to test three correction methods. The Makov-Payne method is insufficient, but combined with the scaling parameters yields an ab initio dielectric constant of 11.6+-4.1 for InP. Gamma point corrections for defect level dispersion are completely incorrect, even for shallow levels, but realigning the total potential in real-space between defect and bulk cells actually corrects the electrostatic defect-defect interaction errors as well. Isolated defect energies to +-0.1 eV are then obtained using a 64 atom supercell, though this does not improve for larger cells. Finally, finite size scaling of known dopant levels shows how to treat the band gap problem: in < or = 200 atom supercells with no corrections, continuing to consider levels into the theoretical conductin band (extended gap) comes closest to experiment. However, for larger cells or when supercell approximation errors are removed, a scissors scheme stretching the theoretical band gap onto the experimental one is in fact correct.
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| 4. |
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| 5. |
- Fransson, Jonas, et al.
(författare)
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A physical compact model for electron transport across single molecules
- 2006
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Ingår i: IEEE transactions on nanotechnology. - 1536-125X .- 1941-0085. ; 5:6, s. 745-749
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Tidskriftsartikel (refereegranskat)abstract
- Prediction of current flow across single molecules requires ab initio electronic structure calculations along with their associated high computational demand, and a means for incorporating open system boundary conditions to describe the voltage sources driving the current. To date, first principle predictions of electron transport across single molecules have not fully achieved a predictive capability. The situation for molecular electronics may be compared to conventional technology computer-aided design (TCAD), whereby various approximations to the Boltzmann transport equation are solved to predict electronic device behavior, but in practice are too time consuming for most circuit design applications. To simplify device models for circuit design, analytical but physically motivated models are introduced to capture the behavior of active and passive devices; however, similar models do not vet exist for molecular electronics. We follow a similar approach by evaluating an analytical model achieved by combining a mesoscopic transport model with parameterizations taken from quantum chemical calculations of the electronic structure of single molecule bonded between two metal contacts. Using the model to describe electron transport across benzene- 1,4-dithiol and by comparing to experiment, we are able to extract the coupling strength of the molecule attached to two infinite metal electrodes. The resulting procedure allows for accurate and computationally efficient modeling of the static (dc) characteristics of a single molecule, with the added capability of being able to study the physical model parameter variations across a range of experiments. Such simple physical models are also an important step towards developing a design methodology for molecular electronics.
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| 6. |
- Intarasiri, S., et al.
(författare)
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Crystalline quality of 3C-SiC formed by high-fluence C+-implanted Si
- 2007
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 253:11, s. 4836-4842
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Tidskriftsartikel (refereegranskat)abstract
- Carbon ions at 40 keV were implanted into (1 0 0) high-purity p-type silicon wafers at 400 degrees C to a fluence of 6.5 x 10(17) ions/cm(2). Subsequent thermal annealing of the implanted samples was performed in a diffusion furnace at atmospheric pressure with inert nitrogen ambient at 1100 degrees C. Time-of-flight energy elastic recoil detection analysis (ToF-E ERDA) was used to investigate depth distributions of the implanted ions. Infrared transmittance (IR) and Raman scattering measurements were used to characterize the formation of SiC in the implanted Si substrate. X-ray diffraction analysis (XRD) was used to characterize the crystalline quality in the surface layer of the sample. The formation of 3C-SiC and its crystalline structure obtained from the above mentioned techniques was finally confirmed by transmission electron microscopy (TEM). The results show that 3C-SiC is directly formed during implantation, and that the subsequent high-temperature annealing enhances the quality of the polycrystalline SiC.
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| 7. |
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| 8. |
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| 9. |
- Jideus, Lena, et al.
(författare)
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Thoracic epidural anesthesia does not influence the occurrence of postoperative sustained atrial fibrillation
- 2001
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Ingår i: Annals of Thoracic Surgery. - 0003-4975 .- 1552-6259. ; 72:1, s. 65-71
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Tidskriftsartikel (refereegranskat)abstract
- Background. To evaluate whether thoracic epidural anesthesia (TEA) can reduce the incidence of atrial fibrillation (AF) after coronary artery bypass grafting (CABG).Methods. Forty-one patients undergoing CABG were treated with TEA intraoperatively and postoperatively. Another 80 patients served as the control group. The sympathetic and parasympathetic activities were evaluated by analysis of neuropeptides, catecholamines and heart rate variability (HRV), preoperatively and postoperatively.Results. Postoperative AF occurred in 31.7% of the TEA-treated patients and in 36.3% of the untreated patients (p = 0.77). TEA significantly suppressed sympathetic activity, as indicated by a less pronounced increase of norepinephrine and epinephrine (p = 0.03, p = 0.02) and a significant decrease of neuropeptide Y (p = 0.01) postoperatively in TEA-treated patients compared to untreated patients. The HRV variable expressing sympathetic activity was significantly lower and the postoperative increase in heart rate was significantly less in the TEA group than in the control group after surgery (p = 0.01, p < 0.001). Among patients developing AF, the maximal number of supraventricular premature beats per minute increased significantly in untreated patients postoperatively but remained unchanged in TEA-treated patients (p = 0.004 versus p = 0.86).Conclusions. TEA has no effect on the incidence of postoperative sustained AF, despite a significant reduction in sympathetic activity.
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| 10. |
- Li, Jiantong, et al.
(författare)
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Ink-jet printed thin-film transistors with carbon nanotube channels shaped in long strips
- 2011
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 109:8, s. 084915-
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Tidskriftsartikel (refereegranskat)abstract
- The present work reports on the development of a class of sophisticated thin-film transistors (TFTs) based on ink-jet printing of pristine single-walled carbon nanotubes (SWCNTs) for the channel formation. The transistors are manufactured on oxidized silicon wafers and flexible plastic substrates at ambient conditions. For this purpose, ink-jet printing techniques are developed with the aim of high-throughput production of SWCNT thin-film channels shaped in long strips. Stable SWCNT inks with proper fluidic characteristics are formulated by polymer addition. The present work unveils, through Monte Carlo simulations and in light of heterogeneous percolation, the underlying physics of the superiority of long-strip channels for SWCNT TFTs. It further predicts the compatibility of such a channel structure with ink-jet printing, taking into account the minimum dimensions achievable by commercially available printers. The printed devices exhibit improved electrical performance and scalability as compared to previously reported ink-jet printed SWCNT TFTs. The present work demonstrates that ink-jet printed SWCNT TFTs of long-strip channels are promising building blocks for flexible electronics.
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