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Vaccine hesitancy is a major threat to COVID-19 vaccination programs. This study aimed to examine the public attitudes towards COVID-19 vaccines, the variance of these attitudes, and associated determinants within a large COVID-19 outbreak in Vietnam |
One-dimensional hybrid nanostructures composed of a plasmonic gold nanowire core covered by a shell of magnetic oxide nanoparticles (Au@FexOy NWs) were synthesized by a one-pot solvothermal synthesis process. The effects of reaction temperature, time, reducing agent, and precursor as well as postsynthesis treatment were optimized to produce highly uniform NWs with a diameter of 226 ± 25 nm and a plasmonic core aspect ratio of 25 to 82. By exploiting the interaction of NWs with an external magnetic field, precise arrangements into highly periodic photonic structures were achieved, which can generate distinctive structural colors that are vividly iridescent and polarization-sensitive. Furthermore, a Bouligand-type chiral nematic film consisting of multistacked unidirectional layers of... |
It is well-known that the amount of glucose in the blood that exceeds the normal sugar blood range can cause diabetes, which is one of the most dangerous diseases that thread human health. Amongst a lot of methods that have been developed to measure glucose levels, electrochemical glucose sensors have attracted more attention due to their accuracy and efficiency. In our work, a simple, instant, and economical chemical process was conducted to deposit NiO nanostructures on the surface of a nickel foam electrode for non-enzymatic glucose electrochemical sensor. The morphologies and components of synthesised materials were characterised by field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. Cyclic voltammetry and chronoamperometry were used to measure ... |
In this paper, a new design of the state observer is proposed to reduce the unstable low-speed region of the adaptive full-order observer (AFO) based speed sensorless speed control of induction motors (IM). The proposed state observer is designed in z-domain rather than in s-domain following the pole-placement approach. The convergence rate of the proposed observer can be made faster than that of the IM poles without extra oscillation effects and the unstable low-speed region of AFO can be reduced to the zero-synchronous-frequency (ZSF) line. Also, a modified adaptation law of the AFO is derived to estimate the rotor speed. Based on the modified AFO, a continuous control set model predictive control (CCS-MPC) is designed for the inner-loop torque control. The cost function of the CC... |
Distichochlamys citrea is an endemic plant species found only in Vietnam, known by folk medicine as a natural antibiotic source. Experimental evidences and computational validation on bioactivity of Distichochlamys citrea M.F. Newman rhizome n-hexane extract against Streptococcus pyogenes were carried out. Experiments found twenty-one bioactive components in the n-hexane extract, which altogether exhibits an overall antibiotic activity of significance against the bacterium; Computations suggested a mechanism based on inhibition of S-ribosylhomocysteine lyase structure. Its biocompatibility and pharmacology were also predicted. |
This letter proposes novel methods for designing two-dimensional (2-D) weight-constrained codes for reducing the parasitic currents in the crossbar resistive memory array. In particular, we present efficient encoding/decoding algorithms for capacity-approaching 2-D weight-constrained codes of size m×n , where each row has a weight pn with p<1/2 ; and each column has a weight qm with q≤1/2 . We show that the designed codes provide higher code rates compared to the prior art codes for p≤1/2 and q≤1/2 . |
This paper introduces a new database of financial crises, providing an important insight into the causes, duration, and consequences of different types of financial crises. Besides extending the systemic banking crises database by Laeven and Valencia (2020) to the period 1970–2019, we develop new approaches for the identification of currency and sovereign debt crises, which we regard as preferable in some respects to those in the literature. Covering 206 countries, our crises database draws on 151 systemic banking crises (1970–2019), 414 currency crises (1950–2019), 200 sovereign debt crises (1960–2019), 75 twin crises (1970–2019), and 21 triple crises (1970–2019). We provide evidence that banking and debt crises tend to coincide or precede currency crises, while debt crises and ban... |
Air pollution has become one of the environmental concerns in recent years due to its harmful threats to human health. To inform people about the air quality in their living areas, it is essential to measure the extent of pollution in the atmosphere. Air pollution sensors are assembled at static, fixed-site measurement monitoring stations to acquire data. The data can be processed at the fixed stations or transmitted to the server to predict the Air Quality Index (AQI). Some previous studies applied machine learning algorithms to predict the AQI. Even though those works showed good performance on specific data, the results are not consistent on different datasets |
This research conducted the effect of different ethanol blends in a conventional gasoline engine under various load and speed conditions for its performance and emission characteristics. The experiment was tested on the test motorcycle designed initially to run by gasoline fuel. The experimental procedure was performed in the motorcycle testbed equipped, measuring power, fuel consumption, and exhaust emissions. NOx and HC emissions of the test vehicle using ethanol blends are lower than gasoline. However, NOx emissions have an opposite trend; they increased approximately 7.4% with E5, 12.3% with E10, and 18.51% with E20 due to the temperature increase. Furthermore, the ethanol contents provide the leaning effect to enhance the air-fuel equivalence ratio to a more excellent value and... |
Modern methods of monitoring help cow farmers save significantly monitoring time and improve cow health care efficiency. Behavioral changes when cows are sick may include increased or decreased daily activities such as increased lying or decreased walking time. Accelerometer advantages are low power consumption, small size, and lightweight. Thus, accelerometers have been widely used to monitor cow behavior. A cow monitoring system usually includes a central processor for receiving and processing information according to a behavioral classification algorithm through the cows’ movements. This paper introduces an effective classification system for Southern Yellow cow behavior using three degrees of freedom (3-DoF) accelerometers. The proposed classifier applied GBDT algorithm (16 seco... |
