In Situ Fabrication and Static Contact Resistance of CdMoO4 Reinforced Cu Matrix Composites.

Particle-reinforced Cu-based electrical contact materials prepared by traditional powder metallurgical methods suffer the same critical problem, where the agglomeration of the addition phases in the Cu matrix significantly deteriorates the performance of the composites and restricts their application. In this work, CdMoO4/Cu matrix composites were fabricated by an in situ method and followed by a powder metallurgical process. Firstly, CdMoO4/particles formed a nucleus and grew up based on the surfaces of Cu particles, realizing the controllable in situ synthesis of mixed powders with homogeneously dispersed CdMoO4 nanoparticles via a one-step reaction. Secondly, the bulk CdMoO4/Cu composites were fabricated by pressing and sintering and then densified by hot-extrusion and cold rolling processes. The microstructures and properties of the extruded and rolled specimens were characterized, respectively. The results indicated that the rolled CdMoO4/Cu composite exhibited excellent comprehensive properties of electrical conductivity and mechanical properties for electrical contact materials. Moreover, the effects of the contact force on the static contact resistance of the extruded and rolled composites were evaluated in the closed state of the contact materials. It was found that the rolled CdMoO4/Cu contact materials possessed a stable electrical contact characteristic with low and steady contact resistance. This work designed ternary CdMoO4 particles to reinforce Cu-based composites with well-balanced performances by an in situ synthesis method and this strategy can be extended to the design of ternary oxide/metal composites utilized as electrical contact materials.

Hot Deformation Behavior and Processing Maps of ZnSnO3/Cu Composites.

In this work, we designed ternary ZnSnO3 particle-reinforced Cu matrix composites and evaluated the hot deformation behavior of ZnSnO3/Cu composites. The hot deformation characteristics of typical dynamic recrystallization were probed by the resulting true stress-strain curves of ZnSnO3/Cu composites. The influences of deformation conditions, including temperatures (650-850 °C) and strain rates (0.01-5 s-1), on the flow stress of the designed composites were investigated. This revealed that the peak stress increased with the increasing of strain rate and decreasing of temperature. Additionally, the activation energy was calculated to be 237.05 kJ/mol and followed by yielding a constitutive equation for low-stress ZnSnO3/Cu composites. The processing maps established by dynamic materials model theory indicated that the designed composites possessed excellent hot workability, and then the processing parameters (790-850 °C and 0.01-0.04 s-1) of the ZnSnO3/Cu composites were determined for practical industrial production. Our work discloses the deformation behavior of ZnSnO3/Cu matrix composites and extends the rational process design for ternary ceramic/metal materials with excellent hot workability.

Bifunctional WC-Supported RuO2 Nanoparticles for Robust Water Splitting in Acidic Media.

We report the strong catalyst-support interaction in WC-supported RuO2 nanoparticles (RuO2 -WC NPs) anchored on carbon nanosheets with low loading of Ru (4.11 wt.%), which significantly promotes the oxygen evolution reaction activity with a η10 of 347 mV and a mass activity of 1430 A gRu -1 , eight-fold higher than that of commercial RuO2 (176 A gRu -1 ). Theoretical calculations demonstrate that the strong catalyst-support interaction between RuO2 and the WC support could optimize the surrounding electronic structure of Ru sites to reduce the reaction barrier. Considering the likewise excellent catalytic ability for hydrogen production, an acidic overall water splitting (OWS) electrolyzer with a good stability constructed by bifunctional RuO2 -WC NPs only requires a cell voltage of 1.66 V to afford 10 mA cm-2 . The unique 0D/2D nanoarchitectures rationally combining a WC support with precious metal oxides provides a promising strategy to tradeoff the high catalytic activity and low cost for acidic OWS applications.

Current Status and Future Perspective of Stenting for Symptomatic Intracranial Atherosclerotic Disease: A Meta-Analysis.

The aim of this study was to evaluate the safety and effectiveness of percutaneous transluminal angioplasty and stenting (PTAS) for intracranial atherosclerotic disease (ICAD) by conducting a meta-analysis. Two independent observers searched PubMed, EMBASE, and Cochrane Library for relevant studies up to 31 December 2016. A meta-analysis was conducted using Review Manager 5.3. Three studies involving 581 cases were included. The meta-analysis indicated that any stroke (RR = 3.13; 95% CI: 1.80-5.42), ischemic stroke (RR = 2.15; 95% CI: 1.19-3.89), and intracranial hemorrhage (RR = 14.71; 95% CI: 1.96-110.48) within 30 days in medical therapy alone were lower compared with PTAS plus medical therapy, but there were no significant differences in any stroke and ischemic stroke beyond 30 days between the two groups. There were also no significant differences in any death and myocardial infarction between the two groups. This meta-analysis demonstrated that, compared with medical therapy alone, PTAS for ICAD had a high risk of complication, but most complications in PTAS group occurred within 30 days after the operation, and beyond 30 days the PTAS was not inferior compared with medical therapy alone. Further studies are needed to reduce the periprocedural complications and reappraise the PTAS.

[Effectiveness of integrative medicine for preventing postoperative recurrence of primary hepatic carcinomas: a systematic review].

OBJECTIVE: To systematically evaluate the effectiveness of integrative medicine (IM) for preventing postoperative recurrence of primary hepatic carcinomas (PHC). METHODS: Such databases as The Cochrane Library, PubMed, EMbase, China National Knowledge Infrastructure (CNKI), VIP Database, Wan-fang Database were retrieved to collect randomized controlled trials (RCTs) on preventing postoperative recurrence of PHC by IM. The retrieval period started from database establishment to June 2013. Literature screening, data extraction, and quality evaluation were performed by two reviewers strictly according to inclusion criteria. Meta-analysis was conducted using RevMan 5.2 Software. RESULTS: A total of 5 RCTs involving 367 patient cases were included. Results of Meta-analysis showed that the IM group was superior to the Western medicine (WM) group in the 1-, 2-, and 3-year recurrence rates (P < 0.05). CONCLUSION: In the prevention of postoperative recurrence of PHC, the effectiveness of IM was more significant, when compared with treatment of Western medicine.