Ab initio calculations of electronic band structure of CdMnS semimagnetic semiconductors

This work is devoted to theoretical investigations of Cd1-xMnxS semimagnetic semiconductors (SMSC). The purpose of this work was to calculate the electronic band structure of ideal and defective Cd1- xMnxS SMSC in both antiferromagnetic (AFM) and ferromagnetic (FM) phases. Ab initio, calculations are performed in the Atomistix Toolkit (ATK) program within the Density Functional Theory (DFT) and Local Spin Density Approximation (LSDA) on Double Zeta Double Polarized (DZDP) basis. We have used Hubbard U potential UMn = 3.59 eV for 3d states for Mn atoms. Supercells of 8 and 64 atoms were constructed. After the construction of Cd1-xMnxS (x = 6.25 %; 25 %) supercells and atom relaxation and optimization of the crystal structure were carried out. Electronic band structure and density of states were calculated, the total energy has been defined in antiferromagnetic (AFM) and ferromagnetic (FM) phases. Our calculations show that the band gap increases with the increase in Mn ion concentration. It has been established that Cd or S vacancy in the crystal structure leads to the change of band gap, Fermi level shifts towards the valence or conduction band.This work is devoted to theoretical investigations of Cd1-xMnxS semimagnetic semiconductors (SMSC). The purpose of this work was to calculate the electronic band structure of ideal and defective Cd1- xMnxS SMSC in both antiferromagnetic (AFM) and ferromagnetic (FM) phases. Ab initio, calculations are performed in the Atomistix Toolkit (ATK) program within the Density Functional Theory (DFT) and Local Spin Density Approximation (LSDA) on Double Zeta Double Polarized (DZDP) basis. We have used Hubbard U potential UMn = 3.59 eV for 3d states for Mn atoms. Supercells of 8 and 64 atoms were constructed. After the construction of Cd1-xMnxS (x = 6.25 %; 25 %) supercells and atom relaxation and optimization of the crystal structure were carried out. Electronic band structure and density of states were calculated, the total energy has been defined in antiferromagnetic (AFM) and ferromagnetic (FM) phases. Our calculations show that the band gap increases with the increase in Mn ion concentration. It has been established that Cd or S vacancy in the crystal structure leads to the change of band gap, Fermi level shifts towards the valence or conduction band

Buckling behavior of multilayer cylindrical shells composed of functionally graded nanocomposite layers under lateral pressure in thermal environments

In this study, the stability behavior of multilayer cylindrical shells made of functionally graded nanocomposite layers (FG-NCLs) subjected to the lateral pressure in thermal environments is investigated. It is postulated that nanocomposite layers forming layered cylindrical shells are made of single-walled carbon nanotube (SWCNT)-reinforced polymers that have four types of profiles based on the uniform and linear distributions of mechanical properties. The material properties of SWCNTs are assumed to be dependent on location as well as temperature and are obtained from molecular dynamics simulations. The governing equations are derived as partial differential equations within shear deformation theory (SDT) and solved in a closed form, using the Galerkin procedure, to determine the lateral critical pressure (LCP) in thermal environments. The numerical representations relate to the buckling behavior of multilayer cylindrical shells made of functionally graded nanocomposite layers under the uniform lateral pressure for different CNT patterns and temperatures within SDT and Kirchhoff-Love theory (KLT)

Ab initio calculations of electronic band structure of CdMnS semimagnetic semiconductors

This work is devoted to theoretical investigations of Cd1-xMnxS semimagnetic semiconductors (SMSC). The purpose of this work was to calculate the electronic band structure of ideal and defective Cd1-xMnxS SMSC in both antiferromagnetic (AFM) and ferromagnetic (FM) phases. Ab initio, calculations are performed in the Atomistix Toolkit (ATK) program within the Density Functional Theory (DFT) and Local Spin Density Approximation (LSDA) on Double Zeta Double Polarized (DZDP) basis. We have used Hubbard U potential UMn = 3.59 eV for 3d states for Mn atoms. Supercells of 8 and 64 atoms were constructed. After the construction of Cd1-xMnxS (x = 6.25 %; 25 %) supercells and atom relaxation and optimization of the crystal structure were carried out. Electronic band structure and density of states were calculated, the total energy has been defined in antiferromagnetic (AFM) and ferromagnetic (FM) phases. Our calculations show that the band gap increases with the increase in Mn ion concentration. It has been established that Cd or S vacancy in the crystal structure leads to the change of band gap, Fermi level shifts towards the valence or conduction band

Bitcoin Heist Ransomware Attack Prediction Using Data Science Process

In recent years, ransomware attacks have become a more significant source of computer penetration. Only general-purpose computing systems with sufficient resources have been harmed by ransomware so far. Numerous ransomware prediction strategies have been published, but more practical machine learning ransomware prediction techniques still need to be developed. In order to anticipate ransomware assaults, this study provides a method for obtaining data from artificial intelligence and machine learning systems. A more accurate model for outcome prediction is produced by using the data science methodology. Understanding the data and identifying the variables are essential elements of a successful model. A variety of machine learning algorithms are applied to the pre-processed data, and the accuracy of each technique is compared to determine which approach performed better. Additional performance indicators including recall, accuracy, and f1-score are also taken into account while evaluating the model. It uses machine learning to predict how the ransomware attack would pan out

InGaN/GaN light-emitting diode with a polarization tunnel junction

Cataloged from PDF version of article.We report InGaN/GaN light-emitting diodes (LED) comprising in situ integrated p(+)-GaN/InGaN/n(+)-GaN polarization tunnel junctions. Improved current spreading and carrier tunneling probability were obtained in the proposed device architecture, leading to the enhanced optical output power and external quantum efficiency. Compared to the reference InGaN/GaN LEDs using the conventional p(+)/n(+) tunnel junction, these devices having the polarization tunnel junction show a reduced forward bias, which is attributed to the polarization induced electric fields resulting from the in-plane biaxial compressive strain in the thin InGaN layer sandwiched between the p(+)-GaN and n(+)-GaN layers. (C) 2013 AIP Publishing LLC

Critical role of CdSe nanoplatelets in color-converting CdSe/ZnS nanocrystals for InGaN/GaN light-emitting diodes

Here we report CdSe nanoplatelets that are incorporated into color-converting CdSe/ZnS nanocrystals for InGaN/GaN light-emitting diodes. The critical role of CdSe nanoplatelets as an exciton donor for the color conversion was experimentally investigated. The power conversion efficiency of the hybrid light-emitting diode was found to increase by 23% with the incorporation of the CdSe nanoplatelets. The performance enhancement is ascribed to efficient exciton transfer from the donor CdSe nanoplatelet quantum wells to the acceptor CdSe/ZnS nanocrystal quantum dots through F�rster-type nonradiative resonance energy transfer. � 2016 Optical Society of America

dReDBox: Materializing a full-stack rack-scale system prototype of a next-generation disaggregated datacenter

Current datacenters are based on server machines, whose mainboard and hardware components form the baseline, monolithic building block that the rest of the system software, middleware and application stack are built upon. This leads to the following limitations: (a) resource proportionality of a multi-tray system is bounded by the basic building block (mainboard), (b) resource allocation to processes or virtual machines (VMs) is bounded by the available resources within the boundary of the mainboard, leading to spare resource fragmentation and inefficiencies, and (c) upgrades must be applied to each and every server even when only a specific component needs to be upgraded. The dRedBox project (Disaggregated Recursive Datacentre-in-a-Box) addresses the above limitations, and proposes the next generation, low-power, across form-factor datacenters, departing from the paradigm of the mainboard-as-a-unit and enabling the creation of function-block-as-a-unit. Hardware-level disaggregation and software-defined wiring of resources is supported by a full-fledged Type-1 hypervisor that can execute commodity virtual machines, which communicate over a low-latency and high-throughput software-defined optical network. To evaluate its novel approach, dRedBox will demonstrate application execution in the domains of network functions virtualization, infrastructure analytics, and real-time video surveillance.This work has been supported in part by EU H2020 ICTproject dRedBox, contract #687632.Peer ReviewedPostprint (author's final draft

Legal rationale of biodiversity regulation as a basis of stable ecological policy

© 2018. ASERS Publishing. All rights reserved. The paper understands cross-border natural resources as a totality of characteristics of local ecological systems, which can act as regulators of human’s life space. Authors state that uniqueness of this phenomenon is defined by the fact that all natural resources act as a single system of planet scale. The problem distinguished in the paper is based on the fact that in the period of ecological systems and natural resources development a little attention is paid to cross-border management on the part of nations they belong to. The research subject is an indicator of stability and quality of management of cross-border natural resources in the aspect of their even existing and carrying out of their functions. Scientific novelty of the research is that it’s proved for the first time that each ecological system has s number of parameters, one of which shows how much it resistant to human impact. The system of providing biodiversity is one of such parameters. In the paper the legal characteristics of the issue are identified with the actual state of interstate cooperation and the opportunity of its expansion within the already existing interstate formation is determined. The example of such formation is European Union. The areas of further research can be defined as an expansion of specified cooperation of Asian and South American continent

Importance of the Caspian Countries for the European Union

When there is a lack of energy resources in the EU and it has to look for suppliers from other countries, Russia provides the world with most of the oil and gas. Diversification of energy resources is one of the objectives for the EU. The majority of international participants are interested in discovering the potential of the sea. However, the development of the region’s resources still faces many obstacles, such as lack of export pipelines, difficulties due to security of supply considerations, transit complications, political and legal considerations and market uncertainties. This study focuses on the countries of the former Soviet Union such as Uzbekistan, Kazakhstan and Turkmenistan in Central Asia, and Azerbaijan in Transcaucasia. One of the six priority areas of the EU in the energy infrastructure of - the Southern Energy Corridor (SEC), the purpose of which is to link the Caspian basin and potentially Middle Eastern gas to Europe. In the article, we analyzed the potential of the Caspian basin in terms of energy and its impact on the energy security of the European Union.Коли в ЄС виникає брак енергоресурсів, і він повинен шукати постачальників з інших країн, Росія забезпечує світ більшістю нафти та газу. Диверсифікація енергетичних ресурсів є однією з цілей для ЄС. Більшість міжнародних учасників зацікавлені у відкритті потенціалу моря. Проте для розвитку ресурсів регіону як і раніше виникають чимало перешкод, таких як відсутність експортних трубопроводів, труднощі з точки зору безпеки поставок, ускладнення транзиту, політичні та правові міркування та невизначеність ринку. Це дослідження присвячено країнам колишнього Радянського Союзу, таким як Узбекистан, Казахстан та Туркменістан в Центральній Азії, а також Азербайджану в Закавказзі. Одна з шести пріоритетних напрямків діяльності ЄС в енергетичній інфраструктурі - Південний енергетичний коридор (SEC), метою якої є з'єднання Каспійського басейну та потенційно ближнього східного газу до Європи. У статті ми проаналізували потенціал Каспійського басейну з точки зору енергії та її вплив на енергетичну безпеку Європейського Союзу.Когда в ЕС отсутствует дефицит энергоресурсов, и он должен искать поставщиков из других стран, Россия предоставляет миру большую часть нефти и газа. Диверсификация энергетических ресурсов является одной из целей для ЕС. Большинство международных участников заинтересованы в обнаружении потенциала моря. Однако развитие ресурсов региона по-прежнему сопряжено со многими препятствиями, такими как отсутствие экспортных трубопроводов, трудности, связанные с безопасностью соображений предложения, осложнениями транзита, политическими и юридическими соображениями и неопределенностью рынка. В этом исследовании основное внимание уделяется странам бывшего Советского Союза, таким как Узбекистан, Казахстан и Туркменистан в Центральной Азии, а также Азербайджан в Закавказье. Один из шести приоритетных направлений ЕС в энергетической инфраструктуре Южного энергетического коридора (SEC), целью которого является увязка Каспийского бассейна и потенциально ближневосточного газа с Европой. В статье мы проанализировали потенциал Каспийского бассейна с точки зрения энергетики и ее влияния на энергетическую безопасность Европейского Союза

A hole accelerator for InGaN/GaN light-emitting diodes

Cataloged from PDF version of article.The quantum efficiency of InGaN/GaN light-emitting diodes (LEDs) has been significantly limited by the insufficient hole injection, and this is caused by the inefficient p-type doping and the low hole mobility. The low hole mobility makes the holes less energetic, which hinders the hole injection into the multiple quantum wells (MQWs) especially when a p-type AlGaN electron blocking layer (EBL) is adopted. In this work, we report a hole accelerator to accelerate the holes so that the holes can obtain adequate kinetic energy, travel across the p-type EBL, and then enter the MQWs more efficiently and smoothly. In addition to the numerical study, the effectiveness of the hole accelerator is experimentally shown through achieving improved optical output power and reduced efficiency droop for the proposed InGaN/GaN LED. (C) 2014 AIP Publishing LLC