The kinetics of the electrochemical degradation of polyaniline (PANI) films has been investigated in 0.5 M sulfuric acid solution at different electrode potentials ranging from 0.3 to 1.0 V vs. Ag/AgCl. Two kinds of P...
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The kinetics of the electrochemical degradation of polyaniline (PANI) films has been investigated in 0.5 M sulfuric acid solution at different electrode potentials ranging from 0.3 to 1.0 V vs. Ag/AgCl. Two kinds of PANI films were used, one doped with poly(styrene sulfonate) (PSS), and the other-with indigotetrasulfonate (ITS). Within a range of relatively low electrode potential (0.3-0.6 V), the degradation was found to proceed at a first-order rate constant of 4 x 10(-5) to 5 x 10(-5) s(-1), corresponding to degradation half-period of 4-5 h. A sharp increase in the degradation rate proceed by extending the electrode potential to higher values, with a maximum rate constant of approximate to2.5 x 10(-3) s(-1) for PANI-PSS, and approximate to1.2 x 10(-3) s(-1) for PANI-ITS films, obtained at a higher potential of 0.9-1.0 V. The data obtained are interpreted by different degradation rate for two distinct redox forms of PANI-emeraldine (slow degradation), and pernigraniline (fast degradation). (C) 2002 Elsevier Science Ltd. All rights reserved.
Background: Resistance of Helicobacter pylori to many antibiotics, which lowers the efficacy of eradication therapy, is increasingly prevalent. High-dose proton pump inhibitor (PPI)-amoxicillin dual therapy (HDDT) has...
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Background: Resistance of Helicobacter pylori to many antibiotics, which lowers the efficacy of eradication therapy, is increasingly prevalent. High-dose proton pump inhibitor (PPI)-amoxicillin dual therapy (HDDT) has been used for H. pylori eradication for years, and resistance to amoxicillin is relatively rare. Although many studies have compared the eradication rate of HDDT with that of guideline therapies, the reported efficacy of HDDT varies greatly and is inconsistent. Aims: This study investigated the eradication rate and adverse effects of HDDT compared with the guidelines at the time of the study. Methods: Several open public databases, including Cochrane, EMBASE, PubMed, and MEDLINE, were searched. The results of the current literature on the eradication and adverse event rates of HDDT compared with the latest recommended first-line therapies were analysed. Notably, 14 out of the 16 included studies were conducted in Asian regions. Results: The eradication rate of HDDT was lower but not significantly different from those of control therapies (odds ratio [OR] = 0.92, 95% confidence interval [CI] = 0.67-1.26) in the intent-to-treat (ITT) analysis. A similar trend was observed in the per-protocol (PP) analysis (OR = 0.88, 95% CI = 0.47-1.63). Notably, the adverse effect risk in HDDT was significantly lower than in other therapies (I2 = 67.75%, OR = 0.42, 95% CI = 0.33-0.54, P = 0.0 0 0 04). When the eradication rate of the control group was lower than 81%, HDDT was significantly better than control therapies (OR = 2.44, 95% CI = 1.23-4.84). Conclusion: HDDT used four times a day for 14 days showed better efficacy and safety than the guideline treatments for H. pylori infection in areas with high antimicrobial resistance. (c) 2024 Elsevier Ltd and International Society of Antimicrobial Chemotherapy. All rights reserved.
High-temperature alloys pose significant challenges in additive manufacturing. These materials have unique properties, such as high resistance to mechanical and chemical degradation when exposed to high temperatures. ...
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High-temperature alloys pose significant challenges in additive manufacturing. These materials have unique properties, such as high resistance to mechanical and chemical degradation when exposed to high temperatures. Furthermore, when these alloys are used to produce hybrid components with other similar alloys, investigating their surface integrity is critical because any residual stress can lead to early stage cracks and poor fatigue performance. In this research, a hybrid manufacturing approach is employed to produce components from difficult to weld alloys, i.e. CM247LC deposited on IN718 through a laser based direct energy deposition (L-DED) process. The surface integrity, mechanical properties and microstructure of such hybrid components is investigated, especially their welding/joint areas. Crack-free processing regimes were established to deposit CM247LC while mitigating the negative effects onto the microstructure of the Inconel substrate. Especially, the thermal gradients were managed to deliver crack free sections of CM247LC with good interface bonding, strength and fine microstructure. It is important to note that this is achieved without any significant preheating that contrasts with what is reported in other investigations so far. Furthermore, end-use hybrid blisks with deposited CM247LC blades onto Inconel 718 disks (HUB) were manufactured and then machined within a single processing set-up. The results show that the substrate thickness, the machining between the deposited layers and the final machining and heat-treatment play a role in reducing residual stresses. Ultimately, such hybrid manufacturing approach can be considered a new solution for producing such components and also for their subsequent repair.
从《达拉斯》(Dallas)、《教父》(The Godfather)、《古驰之家》(House of Gucci)到《继承之战》(Succession),这些影视剧纷纷展现了家族企业内部的恩怨情仇和明争暗斗如何影响企业的兴衰起伏、前途命运,并成为流行文化津津乐道的题材...
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从《达拉斯》(Dallas)、《教父》(The Godfather)、《古驰之家》(House of Gucci)到《继承之战》(Succession),这些影视剧纷纷展现了家族企业内部的恩怨情仇和明争暗斗如何影响企业的兴衰起伏、前途命运,并成为流行文化津津乐道的题材。在现实生活中,由于家族企业的经营状况和个人动态紧密相连,私人恩怨和家族历史难免会渗透到企业管理层面,影响企业的发展。
We present far-ultraviolet spectroscopy of the cores of the massive cooling-flow clusters Abell 1795 and 2597, obtained with the Far Ultraviolet Spectroscopic Explorer. As the intracluster gas cools through 3 x 10(5) ...
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We present far-ultraviolet spectroscopy of the cores of the massive cooling-flow clusters Abell 1795 and 2597, obtained with the Far Ultraviolet Spectroscopic Explorer. As the intracluster gas cools through 3 x 10(5) K, it should emit strongly in the O VI lambda lambda 1032, 1038 resonance lines. We report the detection of O VI lambda 1032 emission in A2597, with a line flux of (1.35 +/- 0.35) x 10(-15) ergs cm(-2) s(-1), as well as detection of emission from C III lambda 977. A marginal detection of C III lambda 977 emission is also reported for A1795. These observations provide evidence for a direct link between the hot (10(7) K) cooling-flow gas and the cool (10(4) K) gas in the optical emission line filaments. Assuming simple cooling-flow models, the O VI line flux in A2597 corresponds to a mass deposition rate of similar to 40 M-. y(-1) within the central 36 kpc. Emission from O VI j1032 was not detected in A1795, with an upper limit of 1.5 x 10(-15) ergs cm(-2) s(-1), corresponding to a limit on the mass cooling-flow rate of (M) over dot (28 kpc) <28 M-. yr(-1). We have considered several explanations for the lack of detection of O VI emission in A1795 and the weaker than expected flux in A2597, including extinction by dust in the outer cluster and quenching of thermal conduction by magnetic fields. We conclude that a turbulent mixing model, with some dust extinction, could explain our O VI results while also accounting for the puzzling lack of emission by Fe XVII in cluster cooling flows.
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