Study on outage performance gap of two destinations on CR-NOMA network

Non-orthogonal multiple access (NOMA) and cognitive radio (CR) are promising for solving the severe spectral scarcity problem encountered by the next generation of wireless communication systems. This study aims to improve spectral efficiency at two secondary destinations by investigating a CR-NOMA network under situation of the perfect successive interference cancellation (SIC). We also derive the exact outage probability for secondary users. Furthermore, an approximate computation method is applied to indicate more insights. It is confirmed that the performance achieved together with performance gap among two users can be obtained due to different power allocation factors assigned to users

Outage performance analysis of cell-center/edge users under two policies of energy harvesting

In this paper, two energy harvesting policies deploying in cooperative non-orthogonal multiple access (NOMA) systems are considered. After period of wireless power transfer, the NOMA users including cell-edge and cell-center users simultaneously transmit the superposition coded symbols to the base station (BS). In the last time slot, the BS decodes to achieve its signal based on superposition coded symbol with corresponding power allocation factors. This paper provides exact expressions of outage probability in two schemes. Performance gap of two NOMA users can be raised by providing different power allocation factors. It is confirmed by numerical result. Distance and data rate are main factors affecting outage performance. Scheme I exhibit scenario where power beacon transmits energy signal to NOMA user while the BS feeds energy to NOMA user in Scheme II. It is shown that outage performance of Scheme I is better than that of Scheme II.Web of Science254807

Fabrication and Magnetic Properties of Mn1 - xZnxFe2O4 (0 ≤ x ≤ 0.8) Nanoparticles

In this paper, we report results on the fabrication and magnetic properties of spinel ferrite Mn1-xZnxFe2O4 (0 ≤ x ≤ 0.8) nanoparticles. The nanoparticles were synthesized by a co-precipitation method. The effects of substituting Zn for Mn on the magnetic properties and particles size were focused. It was found that the phase-formation temperature is 90OC and the average particle size decreases from 40 nm to 10 nm when increased Zn concentration from zero to 0.8. The Curie temperature TC strongly decreases from 585 K (x = 0) to 320 K (x = 0.8) concomitantly with a decrease of the saturation magnetization MS. With a TC of 320 K and MS of 17 emu/g, the x=0.8 sample could be a promising candidate for some biomedical applications

Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

CO CLUSTER FORMATION IN TiO2 DMS AND A METHOD OF ESTIMATION

The paper presents experimental observations of the Co cluster formation in TiO2/Co powder samples prepared by the Sol-Gel method. The obtained X-ray diffraction patterns and Raman scattering show that the anatase phase of TiO2 was successfully synthesized at an annealing temperature of 450°C. Comprehensive studies by means of X-ray diffraction, Raman scattering, thermal magnetization in a temperature range of 300–1000 K and magnetic hysteresis at room temperature confirm that a part of Co did not substitute for Ti in TiO2 structure, otherwise it has reasonably formed cluster of Co in samples. Based on the thermal magnetization curves a method to estimate the magnetic moment per one Co ion substituted for Ti in TiO2 structure was proposed. By means of this method the volume of Co substituted for Ti has been estimated for samples annealed at various temperatures around 450°C. The obtained results show that the volume of Co cluster rises when the annealing temperature increases. This obtained result persuasively explains the large divergence in the magnetic moment per one Co ion reported in the most published papers

Optimal Reactive Power Generation for Radial Distribution Systems Using a Highly Effective Proposed Algorithm

In this paper, a proposed modified stochastic fractal search algorithm (MSFS) is applied to find the most appropriate site and size of capacitor banks for distribution systems with 33, 69, and 85 buses. Two single-objective functions are considered to be reduction of power loss and reduction of total cost of energy loss and capacitor investment while satisfying limit of capacitors, limit of conductor, and power balance of the systems. MSFS was developed by performing three new mechanisms including new diffusion mechanism and two new update mechanisms on the conventional stochastic fractal search algorithm (SFS). As a result, MSFS can reduce 0.002%, 0.003%, and 0.18% of the total power loss from SFS for the three study systems. As compared to other methods, MSFS can reduce power loss from 0.07% to 3.98% for the first system, from 3.7% to 7.3% for the second system, and from 0.92% to 6.98% for the third system. For the reduction of total cost, the improvement level of the proposed method over SFS and two other methods is more significant. It is 0.03%, 1.22%, and 5.76% for the second system and 2.31%, 0.87%, and 3.77% for the third system. It is emphasized that the proposed method can find the global optimal solutions for all study cases while SFS was still implementing search process nearby or far away from the solutions. Furthermore, MSFS can converge to the best solutions much faster than these compared methods. Consequently, it can be concluded that the proposed method is very effective for finding the best location and size of added capacitors in distribution power systems

A Application of G. Polya’s Problem-Solving Process in Teaching High-School Physics

The study investigates the application of G. Polya’s four-step problem-solving process in teaching Physics. This teaching method helps students form and develop problem-solving skills in learning, including (1) Understanding the problem; (2) Making a plan; (3) Executing the plan; (4) Looking back and reflecting. An experimental teaching session on “some forces in practice” for 300 tenth graders in two high schools (grade 10) was conducted as part of this study. Experimental results at first show that more than 80% of students have significantly improved their problem-solving skills. These experimental results are expected to enable teachers and students to teach and learn Physics effectively, meeting the expected outcomes of the General Education Program

Survey on Ecological Ethics Status of Vietnamese Students of Economic and Business Administration Sector in the Current Period

The ecological ethics of students today is not a new issue but has always been of concern, especially during the explosive development of information technology. This study provides information on the ecological ethics situation, the contents, methods, and forms of surveying the ecological ethics status of Vietnamese students in economics and business administration. Through the study, the ecological ethics status of Vietnamese students majoring in economics and business administration has been shown on the following issues: (1) Perception, (2) Consciousness, (3) Standards, and (4) Eco-ethical behavior, thereby proposing some solutions to improve ecological ethics for Vietnamese students in the field of economics and business administration in the current context

Taguchi L₉ (3⁴) Orthogonal Array Design for Photocatalytic Degradation of Methylene Blue Dye by Green ZnO Particles Biosynthesized by <i>Chrysanthemum</i> spp. Flower Extract

The pollution of synthetic dyes in wastewater exerts many negative impacts on the environment and human health. There is an increasing demand for the degradation of dyes, with an emphasis on photocatalysis. Here, we investigated the bio-mediated synthesis of ZnO using Chrysanthemum spp. flower extract and its utilization for the removal of methylene blue dye under sunlight irradiation. The bandgap energy of green ZnO nanoparticles was determined to be 3.0. The Taguchi L9 (34) orthogonal array design was applied to optimize the photocatalytic degradation of methylene blue dye by green ZnO particles. Four parameters, including the initial concentration (10–50 mg/L), ZnO dosage (0.33–1.0 mg), contact time (30–120 min), and pH (4–10) of the solution, were surveyed based on the Taguchi design. We found that the test result (99.0%) at 10 mg/L was almost equivalent to the predicted value (99.5%) of degradation efficiency. The reaction mechanisms shed light on the major role of reactive oxygen species (•O2−, •OH). More importantly, the green ZnO particles could be reused for at least five cycles and demonstrated high stability