Integration Transition Metal Dichalcogenide Heterostructures in Plasmonic Cavities

University of Technology Sydney. Faculty of Science.The emergence of interlayer excitons from atomically layered transition metal dichalcogenides (TMDs) heterostructures has drawn a tremendous attention due to their unique and exotic optoelectronic properties. Coupling the TMD van der Waals heterostructures into optical cavities provides distinctive electromagnetic environments which plays an important role in controlling multiple optical processes such as optical nonlinear generation or photoluminescence (PL) enhancement. However, there is a gap in current research on the integration of interlayer excitons in TMDs heterostructures and optical cavities, especially plasmonic cavities. To address this shortage, this project is devoted to investigating the light and matter interaction between the interlayer excitons and plasmonic nanocavities based on a nanogap plasmonic structure consisting of a silver nanocube on a flat metallic mirror. Spectroscopic studies reveal an order of magnitude enhancement of the interlayer exciton at room temperature and a 5-time enhancement in fluorescence at cryogenic temperature. Also, finite-difference time-domain (FDTD) simulations of the plasmonic cavity system was carried out to elucidate the mechanism of the enhancement, despite of low spontaneous radiative decay rate enhancement. As a result, enhancement of the emission is based on increasing excitation efficiency and Purcell effect from the cavity. Our results show a novel method to control the excitonic processes in TMDs heterostructures to build high performance nanophotonic and optoelectronic devices

SOUND TRANSMISSION ACROSS A FINITE SIMPLY SUPPORTED DOUBLE-LAMINATED COMPOSITE PLATE WITH ENCLOSED AIR CAVITY

ABSTRACTSound transmission across a finite orthotropic laminated double-composite plate with enclosed air cavity on an infinite acoustic rigid baffle is investigated analytically. Sound velocity potential method combined with simply supported boundary conditions is used instead of traditional methods, has good scalability and is important for studies of acoustic vibration of structures. The sound transmission loss is calculated from the ratio of incident to transmitted acoustic powers. Specifically, the focus is placed on the effects of several key system parameters on sound transmission including the plate dimensions, the laminate configurations, the boundary conditions, and the composite materials are systematically examined

Enhancing Security and Robustness for SDN-Enabled Cloud Networks

Software-Defined Networking is an emerging network architecture which promises to solve the limitations associated with current cloud computing systems based on traditional network. The main idea behind SDN is to separate control plane from networking devices, thereby providing a centralized control layer integrable to cloud-based infrastructure. The integration of SDN and Cloud Computing brings an immense benefits to network deployment and management, however, this model still faces many critical challenges with regards to availability, scalability and security. In this study, we present a security and robustness SDN-Enabled Cloud model using OpenStack and OpenDaylight. In particular, we design and implement a security clustering-based SDN Controller for monitoring and managing cloud networking, and a hardware platform to accelerate packet processing in virtual switches. We evaluate our proposed model on a practical cloud testbed consisting of several physical and virtual nodes. The experiment results show that the SDN controller cluster significantly improve robustness for the network even in case of being attacked by abnormal network traffic; while the hardware-accelerated switches can be operated in highperformance and well-adapted to the cloud environment

Static and dynamic analysis of laminated composite plates with integrated piezoelectrics

A Finite Element model based on First-order Shear Deformation Theory is developed for the static shape control and vibration control of la minated composite plates integrated with piezoelectric sensors and actuators. A nine-node isoparametric rectangular element with 45 degrees of freedom for the generalized displacements and 2 electrical degrees of freedom is implemented for the static and dynamic analyses. The model is validated by comparing with existing results documented in the literature. Some numerical results are presented. It is concluded that the shape of the piezoelectric laminated composite plates can reach the desired shape through passive control or active control. The influence of stacking sequence of composite plates and position of piezoelectric layers and sensors/actuators patches on the response of the piezoelectric composite plates is evaluated

INVESTIGATION OF THE ANTIBIOTIC RESISTANCE: THE CASE OF BUU DIEN GENERAL HOSPITAL IN HO CHI MINH CITY

Objective: In Vietnam, antibiotic resistance has been gained the attention of medical professionals in antibiotic use management. This study aimed to investigate the antibiotic resistance among hospital-acquired infections at Buu Dien General Hospital in Ho Chi Minh City in the period of 01-12/2017. Methods: This cross-sectional descriptive study was conducted on the retrospective data of all antibiograms of bacteria isolated from hospital-acquired infections at Buu Dien General Hospital in Ho Chi Minh City in the period of 01-12/2017 to investigate the antibiotic resistance. Characteristics of antibiotic resistance were described by frequency and percentage of types of bacteria isolated and antibiotics being resistant. Results: A total of 179 isolates were collected during the period 01-12/2017, of which E. coli was the most commonly isolated pathogen (41.3%). The highest prevalent infections were in the skin and mucosa; respiratory tract; and urinary tract (34.6%; 32.4%; and 27.9%). The antibiotic susceptibility testing used 21 types of antibiotics. Among them, S. aureus was 82% resistant to clindamycin and 75% resistant to cefuroxime; the Proteus resistance percentages to amoxicillin/clavulanic, second-generation cephalosporins, ciprofloxacin and fosfomycin varied from 50 to 93%; Pseudomonas was 92% resistant to fosfomycin and 62% resistant to ceftazidime; A. baumannii was resistant to most classes of agents used (50-75%). Both E. coli and Klebsiella were highly resistant to gentamicin, amoxicillin, ciprofloxacin, 2nd and 3rd generation cephalosporin’s. Polymyxin B-resistant Proteus cultures were detected at 67%. Conclusion: The study described the antibiotic resistance situation of hospital-acquired bacteria at the Buu Dien General Hospital from 01-12/2017. This information will aid physicians to select proper antibiotics for their patients in the next period

Catalytic Dye Oxidation over CeO2 Nanoparticles Supported on Regenerated Cellulose Membrane

A novel regenerated cellulose (RC) membrane containing cerium oxide (CeO2) nanoparticles is described in detail. In this work, CeO2 nanoparticles with high surface area and mesoporosity were prepared by a modified template-assisted precipitation method. Successful synthesis was achieved using cerium nitrate as a precursor, adjusting the final pH solution to around 11 by ammonium hydroxide and ethylene diamine, and annealing at 550 °C for 3 hours under a protective gas flow. This resulted in a surface area of 55.55 m².g–1 for the nanoparticles. The regenerated cellulose membrane containing CeO2 particles was synthesized by the novel and environmentally friendly method. The catalyst CeO2 and cellulose/CeO2 membrane were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Electron paramagnetic resonance (EPR), and Brunauer-Emmett-Teller (BET) measurements. The g-value of 2.276 has confirmed the presence of the surface superoxide species of CeO2 nanoparticles in EPR. The photocatalytic activity of the catalyst and the membrane containing the catalyst was evaluated through the degradation of methylene blue under visible light irradiation by UV-VIS measurements. The cellulose/CeO2 membrane degraded 80% of the methylene blue solution in 120 minutes, showing a better photocatalytic activity than the CeO2 catalyst, which degraded approximately 62% in the same period. It has been proven that the RC membrane is not only a good transparent supporting material but also a good adsorption for high-performance of CeO2 catalyst. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Microfluidic Chip for Trapping Magnetic Nanoparticles and Heating in Terms of Biological Analysis

In this study, we reported the results of the design and the fabrication a planar coil in copper (square, a = 10 mm, 15mm high, 90 turns), these planar coils were integrated in a microfluidic chip for trapping magnetic nanoparticles and local heating applications. A small thermocouple (type K, 1 mm tip size) was put directly on top of the micro-channel in poly(dimethyl-siloxane) in order to measure the temperature inside the channel during applying current. The design of planar coils was based on optimizing the results of the magnetic calculation. The most suitable value of the magnetic field generated by the coil was calculated by ANSYS® software corresponded to the different distances from the coil surface to the micro-channel bottom (magnetic field strength Hmax = 825 A/m). The magnetic filed and heating relationship was balanced in order to manipulating the trapping magnetic nanoparticles and heating process. This design of the microfluidic chip can be used to develop a complex microfluidic chip using magnetic nanoparticles

Develop algorithms to determine the status of car drivers using built-in accelerometer and GBDT

In this paper, we introduce a mobile application called CarSafe, in which data from the acceleration sensor integrated on smartphones is exploited to come up with an efficient classification algorithm. Two statuses, "Driving" or "Not driving," are monitored in the real-time manner. It enables automatic actions to help the driver safer. Also, from these data, our software can detect the crash situation. The software will then automatically send messages with the user's location to their emergency departments for timely assistance. The application will also issue the same alert if it detects a driver of a vehicle driving too long. The algorithm's quality is assessed through an average accuracy of 96.5%, which is better than the previous work (i.e., 93%)

Lower and upper bound intercept probability analysis in amplifier-and-forward time switching relaying half-duplex with impact the eavesdropper

In this paper, we proposed and investigated the amplifier-and-forward (AF) time switching relaying half-duplex with impact the eavesdropper. In this system model, the source (S) and the destination (D) communicate with each other via a helping of the relay (R) in the presence of the eavesdropper (E). The R harvests energy from the S and uses this energy for information transferring to the D. For deriving the system performance, the lower and upper bound system intercept probability (IP) is proposed and demonstrated. Furthermore, the Monte Carlo simulation is provided to justify the correctness of the mathematical, analytical expression of the lower and upper bound IP. The results show that the analytical and the simulation curves are the same in connection with the primary system parameters