INTRODUCTIONAll corrosion processes -- general corrosion, pitting attack, crevice corrosion, and stress corrosion cracking (SCC), as well as passive film buildup -- cause spontaneous fluctuations of ...the free-corrosion potential of the electrodes. These fluctuations are termed electrochemical noise (EN), and their analysis is used widely in the examination of different corrosion processes.1-10 Although interest in EN analysis has increased in corrosion studies over the past 15 years, some doubt remains on the correlation between the occurring phenomenon and the signal generated. From a qualitative point of view, it has been reported that values of statistical parameters of EN, such as standard deviation ( ) and the root-mean-squared (rms) values of the potential, can represent the corrosion status of the metal and permit identification of the nature of attack.1-2,11 Some tentative correlations between and the corrosion parameters (corrosion current and polarization resistance Rp) have been proposed,4,8,12 but their application seems not to be so general. In the last few years, interest in the current noise has grown. The study of the current fluctuations between corroding electrodes seems to be more significant than potential studies.7-8 More recently, use of the noise resistance (Rn) as calculated from potential and current noise data was proposed to be equivalent to Rp.13-17 Much discussion can be found in the literature on this topic, and a deeper analysis is required. A powerful analysis of EN acquisitions can be performed by transposing data in the frequency do-
The Beijing Electron Spectrometer III (BESIII) is a multipurpose detector operating on the Beijing Electron Positron Collider II (BEPCII). After more than ten years operation, the efficiency of the ...inner layers of the Main Drift Chamber (MDC) decreased significantly. To solve this issue, the BESIII collaboration is planning to replace the inner part of the MDC with three layers of Cylindrical triple Gas Electron Multipliers (CGEM).
The transverse plane spatial resolution of CGEM is required to be 120μm or better. To meet this goal, a careful calibration of the detector is necessary to fully exploit the potential of the CGEM detector. In all the calibrations, the detector alignment plays an important role to improve the detector precision. The track-based alignment for the CGEM detector with the Millepede algorithm is implemented to reduce the uncertainties of the hit position measurement. Using the cosmic-ray data taken in 2020 with the two layers setup, the displacement and rotation of the outer layer with respect to the inner layer is determined by a simultaneous fit applied to more than 160000 tracks. A good alignment precision has been achieved that guarantees the design request could be satisfied in the future. A further alignment is going to be performed using the combined information of tracks from cosmic-ray and collisions after the CGEM is installed into the BESIII detector.
A practical strategy is presented and successfully implemented to determine form factors in the time-like but unphysical (below threshold) region using dispersion relations, in a model independent ...way without any bias towards expected resonances. Space and time-like data have been employed along with a regularization scheme to unfold and solve the integral equations. Remarkably, resonance structures with peaks for the
ϱ(770),
ϱ′(1600) and a structure near the
N
N
threshold are automatically generated. The Φ peak is invisible thus refuting suggestions about any sizeable
s
s
content in the nucleon.
Abstract This study compares the effects of two polymers currently being marketed on commercially available drug-eluting stents, PVDF-HFP fluorinated copolymer (FP) and phosphorylcholine polymer ...(PC), on re-endothelialization, acute thrombogenicity, and monocyte adhesion and activity. Rabbit iliac arteries were implanted with cobalt–chromium stents coated with FP or PC polymer (without drug) and assessed for endothelialization at 14 days by confocal and scanning electron microscopy (SEM). Endothelialization was equivalent and near complete for FP and PC polymer-coated stents (>80% by SEM). Acute thrombogenicity was assessed in a Chandler loop model using porcine blood. Thrombus adherence was similar for both polymers as assessed by clot weight, thrombin–antithrombin III complex, and lactate dehydrogenase expression. In vitro cell adhesion assays were performed on FP and PC polymer-coated glass coupon surfaces using HUVECs, HCAECs, and THP-1 monocytes. The number of ECs adhered to FP and control surfaces were equivalent and significantly greater than on PC surfaces ( p < 0.05). There were no differences in THP-1 monocyte adhesion and cytokine (MCP-1, RANTES, IL-6, MIP-1α, MIP-1β, G-CSF) expression. The data suggests that biological responses to both FP and PC polymer are similar, with no mechanistic indication that these polymers would be causative factors for delayed vessel healing in an acute timeframe.
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