RESUMO
Storage batteries with elevated energy density, superior safety and economic costs continues to escalate. Batteries can pose safety hazards due to internal short circuits, open circuits and other malfunctions during usage, hence real-time surveillance and error diagnosis of the battery's operational state is imperative. In this paper, a three-dimensional model of electrochemical-magnetic field-thermal coupling is formulated with lithium-ion pouch cells as the research focus, and the spatial distribution pattern of the physical field such as magnetic field and temperature when the battery is operational is acquired. Furthermore, this manuscript also investigates the diagnostic methodology for defective batteries with internal short circuits and fissures, that is, the operational state of the battery is evaluated and diagnosed by the distribution of the magnetic field surrounding the battery. To substantiate the method's practical viability, the present study extends its examination to the 18650-battery pack. We obtained the magnetic field images of the normal operation of the battery pack and the failure state of some batteries and analyzed the relationship between the magnetic field distribution characteristics and the performance of the battery pack, providing a new method for the health monitoring and fault diagnosis of the battery pack. This non-contact method incurs no damage to the battery, concurrently exhibiting elevated sensitivity and extremely rapid response time. Meanwhile, it provides an effective means for non-destructive research on the batteries and can be applied to areas such as battery safety screening and non-destructive testing. This research not only helps to facilitate our understanding of the battery's operating mechanism, but also provides robust support for safe operation and optimal battery design.
RESUMO
OBJECTIVE: To investigate effect of clinical pathway management on pediatric pneumonia. METHOD: Data were colleted from children hospitalizated with bronchial pneumonia, bronchiolitis, mycoplasma pneumonia in Center of Respiratory Disorders in Children's Hospital of Chongqing Medical University from January 2011 to December 2012. According to implement of clinical pathway management, all patients were divided into pathway management group (n = 405) and non-pathway management group (n = 503). Length of stay, costs of hospitalization, clinical effect and use of antibiotics were compared in these two groups. RESULT: In pathway management group, average length of stay of children with bronchial pneumonia and bronchiolitis was (6.1 ± 1.6) d and (6.2 ± 1.5) d respectively. While in non-pathway management group, length of stay was (7.2 ± 1.9) d and (7.3 ± 1.5) d (P = 0.000). There was no significant difference in length of stay between these two groups of children with mycoplasma pneumonia [ (6.9 ± 1.8) d vs.(7.7 ± 2.5) d] (P = 0.198). Costs of auxiliary tests in pathway management group was slightly higher than that in non-pathway management group. While other costs in pathway management group were significantly lower than those in non-pathway management group. Total costs of hospitalization of patients with these three diseases in pathway management group and non-pathway management group were ¥(4609 ± 1225) vs ¥ (5629 ± 1813) , ¥ (5006 ± 1250) vs. ¥ (5686 ± 1337), ¥ (4946 ± 1259) vs. ¥ (6488 ± 3032) respectively. There was a significant difference (P < 0.05). Percentages of antibiotics use in two groups were 70.9% vs.99.4%, 45.7% vs.93.4% and 96.2% vs.100.0%. Antibiotics related indicators such as mean number of day of use, ratio of combination and grade of antibiotics were significantly higher in pathway management group compared to non-pathway management group (P < 0.01). There was no significant difference in other indicators like clinical effect and unscheduled readmission in 30 days between two groups (P > 0.05). CONCLUSION: Clinical pathway management can regulate medical behaviors through reduction of medical costs, avoidance of excessive laboratory tests and therapy, and regulation of antibiotic use.