2,426 research outputs found
Plasma analysis of Inductively Coupled Impulse Sputtering of Cu, Ti and Ni
Inductively coupled impulse sputtering (ICIS) is a new development in the field of highly ionised pulsed PVD processes. For ICIS the plasma is generated by an internal inductive coil, replacing the need for a magnetron.
To understand the plasma properties, measurements of the current and voltage waveforms at the cathode were conducted. The IEDFs were measured by energy resolved MS and plasma chemistry was analysed by OES and then compared to a model.
The target was operated in pulsed DC mode and the coil was energised by pulsed RF power, with a duty cycle of 7.5 %. At a constant pressure (14 Pa) the set peak RF power was varied from 1000-4000 W. The DC voltage to the target was kept constant at 1900 V.
OES measurements have shown a monotonic increase in intensity with increasing power. Excitation and ionisation processes were single step for ICIS of Ti and Ni and multi-step for Cu. The latter exhibited an unexpectedly steep rise in ionisation efficiency with power.
The IEDFs measured by MS show the material- and time- dependant plasma potential in the range of 10-30 eV, ideal for increased surface mobility without inducing lattice defects. A lower intensity peak, of high energetic ions, is visible at 170 eV during the pulse
Development of High-Speed Fluorescent X-Ray Micro-Computed Tomography
A high-speed fluorescent x-ray CT (FXCT) system using monochromatic synchrotron x rays was developed to detect very low concentration of medium-Z elements for biomedical use. The system is equipped two types of high purity germanium detectors, and fast electronics and software. Preliminary images of a 10mm diameter plastic phantom containing channels field with iodine solutions of different concentrations showed a minimum detection level of 0.002 mg I/ml at an in-plane spatial resolution of 100µm. Furthermore, the acquisition time was reduced about 1/2 comparing to previous system. The results indicate that FXCT is a highly sensitive imaging modality capable of detecting very low concentration of iodine, and that the method has potential in biomedical applications
The Human Cytomegalovirus UL76 Gene Regulates the Level of Expression of the UL77 Gene
Human cytomegalovirus (HCMV) can be reactivated under immunosuppressive conditions causing several fatal pneumonitis, hepatitis, retinitis, and gastrointestinal diseases. HCMV also causes deafness and mental retardation in neonates when primary infection has occurred during pregnancy. In the genome of HCMV at least 194 known open reading frames (ORFs) have been predicted, and approximately one-quarter, or 41 ORFs, are required for viral replication in cell culture. In contrast, the majority of the predicted ORFs are nonessential for viral replication in cell culture. However, it is also possible that these ORFs are required for the efficient viral replication in the host. The UL77 gene of HCMV is essential for viral replication and has a role in viral DNA packaging. The function of the upstream UL76 gene in the HCMV-infected cells is not understood. UL76 and UL77 are cistons on the same viral mRNA and a conventional 5' mRNA for UL77 has not been detected. The vast majority of eukaryotic mRNAs are monocistronic, i.e., they encode only a single protein.To determine whether the UL76 ORF affects UL77 gene expression, we mutated UL76 by ORF frame-shifts, stop codons or deletion of the viral gene. The effect on UL77 protein expression was determined by either transfection of expression plasmids or infection with recombinant viruses. Mutation of UL76 ORF significantly increased the level of UL77 protein expression. However, deletion of UL76 upstream of the UL77 ORF had only marginal effects on viral growth.While UL76 is not essential for viral replication, the UL76 ORF is involved in regulation of the level of UL77 protein expression in a manner dependent on the translation re-initiation. UL76 may fine-tune the UL77 expression for the efficient viral replication in the HCMV- infected cells
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Z boson production in Pb+Pb collisions at √Snn = 5.02 TeV measured by the ATLAS experiment
The production yield of Z bosons is measured in the electron and muon decay channels in Pb+Pb collisions at √S = 5.02 TeV with the ATLAS detector. Data from the 2015 LHC run corresponding to an integrated luminosity of 0.49 nb are used for the analysis. The Z boson yield, normalised by the total number of minimum-bias events and the mean nuclear thickness function, is measured as a function of dilepton rapidity and event centrality. The measurements in Pb+Pb collisions are compared with similar measurements made in proton-proton collisions at the same centre-of-mass energy. The nuclear modification factor is found to be consistent with unity for all centrality intervals. The results are compared with theoretical predictions obtained at next-to-leading order using nucleon and nuclear parton distribution functions. The normalised Z boson yields in Pb+Pb collisions lie 1-3σ above the predictions. The nuclear modification factor measured as a function of rapidity agrees with unity and is consistent with a next-to-leading-order QCD calculation including the isospin effect. nn -
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Measurement of Azimuthal Anisotropy of Muons from Charm and Bottom Hadrons in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector.
The elliptic flow of muons from the decay of charm and bottom hadrons is measured in pp collisions at sqrt[s]=13 TeV using a data sample with an integrated luminosity of 150 pb^{-1} recorded by the ATLAS detector at the LHC. The muons from heavy-flavor decay are separated from light-hadron decay muons using momentum imbalance between the tracking and muon spectrometers. The heavy-flavor decay muons are further separated into those from charm decay and those from bottom decay using the distance-of-closest-approach to the collision vertex. The measurement is performed for muons in the transverse momentum range 4-7 GeV and pseudorapidity range |η|<2.4. A significant nonzero elliptic anisotropy coefficient v_{2} is observed for muons from charm decays, while the v_{2} value for muons from bottom decays is consistent with zero within uncertainties
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Measurement of W± boson production in Pb+Pb collisions at √sNN=5.02Te with the ATLAS detector
A measurement of W± boson production in Pb+Pb collisions at sNN=5.02Te is reported using data recorded by the ATLAS experiment at the LHC in 2015, corresponding to a total integrated luminosity of 0.49nb-1. The W± bosons are reconstructed in the electron or muon leptonic decay channels. Production yields of leptonically decaying W± bosons, normalised by the total number of minimum-bias events and the nuclear thickness function, are measured within a fiducial region defined by the detector acceptance and the main kinematic requirements. These normalised yields are measured separately for W+ and W- bosons, and are presented as a function of the absolute value of pseudorapidity of the charged lepton and of the collision centrality. The lepton charge asymmetry is also measured as a function of the absolute value of lepton pseudorapidity. In addition, nuclear modification factors are calculated using the W± boson production cross-sections measured in pp collisions. The results are compared with predictions based on next-to-leading-order calculations with CT14 parton distribution functions as well as with predictions obtained with the EPPS16 and nCTEQ15 nuclear parton distribution functions. No dependence of normalised production yields on centrality and a good agreement with predictions are observed for mid-central and central collisions. For peripheral collisions, the data agree with predictions within 1.7 (0.9) standard deviations for W- (W+) bosons
Measurement of J/ψ production in association with a W ± boson with pp data at 8 TeV
A measurement of the production of a prompt J/ψ meson in association with a W± boson with W± → μν and J/ψ → μ+μ− is presented for J/ψ transverse momenta in the range 8.5–150 GeV and rapidity |yJ/ψ| < 2.1 using ATLAS data recorded in 2012 at the LHC. The data were taken at a proton-proton centre-of-mass energy of s = 8 TeV and correspond to an integrated luminosity of 20.3 fb−1. The ratio of the prompt J/ψ plus W± cross-section to the inclusive W± cross-section is presented as a differential measurement as a function of J/ψ transverse momenta and compared with theoretical predictions using different double-parton-scattering cross-sections. [Figure not available: see fulltext.]
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