234 research outputs found
Synergic Effect of CaI and LiI on Ionic Conductivity of Solution-Based Synthesized Li7P3S11 Solid Electrolyte
Li7P3S11 doped with CaX2 (X = Cl, Br, I) and LiI solid electrolytes were successfully prepared by liquid-phase synthesis using acetonitrile as the reaction medium. Their structure was investigated using XRD, Raman spectroscopy and SEM-EDS. The data obtained from complex impedance spectroscopy was analyzed to study the ionic conductivity and relaxation dynamics in the prepared samples. The XRD results suggested that a part of CaX2 and LiI incorporated into the structure of Li7P3S11, while the remaining part existed at the grain boundary of the Li7P3S11 particle. The Raman peak positions of PS43- and P2S74- ions in samples 90Li7P3S11-5CaI2 and 90Li7P3S11-5CaI2-5LiI had shifted as compared to the Li7P3S11 sample, showing that CaI2 addition affected the vibration of PS43- and P2S74- ions. EDS results indicated that CaI2 and LiI were well dispersed in the prepared powder sample. The ionic conductivity at 25 °C of sample 90Li7P3S11-5CaI2-5LiI reached a very high value of 3.1 mS cm-1 due to the improvement of Li-ion movement at the grain boundary and structural improvement upon CaI2 and LiI doping. This study encouraged the application of Li7P3S11 in all-solid-state Li-ion batteries
On the Effects of Monetary Policy in Vietnam: Evidence from a Trilemma Analysis
During and after the 2008-2009 global financial crisis, the growth cycle of Vietnam’s economy has shifted from an average annual growth rate of 7%-8% to an average annual growth rate of 5%-6% with a high level of macroeconomic instability and uncertainty from 2009 till 2016. Related studies have speculated that the operations of monetary policies during this period were not effective in recovering the economic growth and stabilizing the overall price level and total output level. This paper provides the first empirical examination of this speculation using the Trilemma framework. Our empirical results show that the State Bank of Vietnam has had adopted a set of policies aiming at maintaining exchange rate stability and interest rate independence while easing the restrictions on capital inflows. The combination of these three monetary policy approaches is found to violate the rule of Trilemma. Consequently, exchange rate and interest rate policies became less effective and failed to stabilize the economy in response to the global economic recession
High Temperature Symmetry Non-Restoration And Inverse Symmetry Breaking in the Z2Ă—Z2 Model
The patterns of high temperature symmetry non-restoration (SNR) and inverse symmetry braking (ISB) in the Z2Ă—Z2model are investigated in detail for a specified parameters
Survey on Vietnamese teachers’ perspectives and perceived support during COVID-19
The COVID-19 pandemic has caused unprecedented damage to the educational system worldwide. Besides the measurable economic impacts in the short-term and long-term, there is intangible destruction within educational institutions. In particular, teachers – the most critical intellectual resources of any schools – have to face various types of financial, physical, and mental struggles due to COVID-19. To capture the current context of more than one million Vietnamese teachers during COVID-19, we distributed an e- survey to more than 2,500 randomly selected teachers from two major teacher communities on Facebook from 6th to 11th April 2020. From over 373 responses, we excluded the observations which violated our cross-check questions and retained 294 observations for further analysis. This dataset includes: (i) Demographics of participants; (ii) Teachers' perspectives regarding the operation of teaching activities during the pandemic; (iii) Teachers' received support from their schools, government bodies, other stakeholders such as teacher unions, and parents' associations; and (iv) teachers' evaluation of school readiness toward digital transformation. Further, the dataset was supplemented with an additional question on the teachers' primary source of professional development activities during the pandemic
Sex differences in clinical characteristics, hospital management practices, and in-hospital outcomes in patients hospitalized in a vietnamese hospital with a first acute myocardial infarction
BACKGROUND: Cardiovascular disease is one of the leading causes of morbidity and mortality in Vietnam. We conducted a pilot study of Hanoi residents hospitalized with acute myocardial infarction (AMI) at the Vietnam National Heart Institute in Hanoi. The objectives of this observational study were to examine sex differences in clinical characteristics, hospital management, in-hospital clinical complications, and mortality in patients hospitalized with an initial AMI.
METHODS: The study population consisted of 302 Hanoi residents hospitalized with a first AMI at the largest tertiary care medical center in Hanoi in 2010.
RESULTS: The average age of study patients was 66 years and one third were women. Women were older (70 vs. 64 years) and were more likely than men to have had hyperlipidemia previously diagnosed (10% vs. 2%). During hospitalization, women were less likely to have undergone percutaneous coronary intervention (PCI) compared with men (57% vs. 74%), and women were more likely to have developed heart failure compared with men (19% vs. 10%). Women experienced higher in-hospital case-fatality rates (CFRs) than men (13% vs. 4%) and these differences were attenuated after adjustment for age and history of hyperlipidemia (OR: 2.64; 95% CI: 1.01, 6.89), and receipt of PCI during hospitalization (OR: 2.09; 95% CI: 0.77, 5.09).
CONCLUSIONS: Our pilot data suggest that among patients hospitalized with a first AMI in Hanoi, women experienced higher in-hospital CFRs than men. Full-scale surveillance of all Hanoi residents hospitalized with AMI at all Hanoi medical centers is needed to confirm these findings. More targeted and timely educational and treatment approaches for women appear warranted
Dataset of Vietnamese teachers’ perspectives and perceived support during the COVID-19 pandemic
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