RESUMEN
With the rapid development of electronic information technology, dielectric ceramics are widely used in the field of passive devices such as multi-layer ceramic capacitors. In this paper, (Bi2/3W1/3)xTi1-xO2 (BWTOx) ceramics with superior dielectric properties have been prepared by using a traditional solid-state method. Remarkably, at a (Bi2/3W1/3)4+ doping level of 0.01, a (Bi2/3W1/3)0.01Ti0.99O2 ceramic achieved a giant dielectric permittivity of â¼1.5 × 104 and a low loss tangent of â¼0.07 at 1 kHz, as well as a good temperature independence, which could satisfy the operating temperature standards for X9R capacitors. The abnormal dielectric relaxation in the low temperature region can be explained by the interface polarization. Data based on the complex impedance spectroscopy and X-ray photoemission spectroscopy results indicate that the colossal permittivity of BWTOx ceramics is mainly ascribed to the internal barrier layer capacitance effect. The findings of this work could provide valuable insights for achieving large dielectric constants and good temperature stability simultaneously in BWTOx and other related electronic ceramic materials.
RESUMEN
OBJECTIVE: Conducting a meta-analysis to evaluate the efficacy of artificial liver support system (ALSS) in the treatment of hepatic failure in China. METHODS: Clinical trials comparing ALSS vs. routine medical treatment of hepatic failure in China were identified from computer-based literature. The pooled odds ratio and 95% confidence interval (CI) of prognostic indicators, such as survival rate and clinical improvement rate at discharge, were used to measure the magnitude of the efficacy. RESULTS: Ten trials including 1030 patients were identified. The odds ratio (95% CI) of survivorship or improvement of ALSS over routine medical treatment in early, intermediate and advanced stages of hepatic failure were 3.72 (2.03-6.83), 2.79 (2.88-4.14) and 1.85 (0.96-3.56) respectively. CONCLUSION: ALSS treatment is more effective in early and intermediate stages of hepatic failure than routine medical treatment, but not in its advanced stage.