632 resultados para Superlattices (SLs)


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This piece was given at the SLS 2012 in the Restitution sub-section. It was one of two finalists for the best paper at the Restitution section that year.

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Accelerated probabilistic modeling algorithms, presenting stochastic local search (SLS) technique, are considered. General algorithm scheme and specific combinatorial optimization method, using “golden section” rule (GS-method), are given. Convergence rates using Markov chains are received. An overview of current combinatorial optimization techniques is presented.

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The resistance of semiconductor superlattices under weak magnetic fields is modelled with a classical approach. It is shown, that this is sufficient to explain the experimental features of these systems and that a quantum-mechanical approach will only be needed for significantly smaller lattice structures.

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The purpose of this study was twofold. It was designed to determine (a) the efficacy of an intervention designed to increase the frequencies of appropriate study behaviors on the part of community college students who were preparing for academic mathematics activities and (b) whether any increase in appropriate study behavior frequency was accompanied by increased academic achievement in college preparatory mathematics classes. A total of 126 Miami Dade College students participated in this study. Two developmental (remedial) mathematics classes were randomly assigned as the experimental group, and two others were assigned as the control group. All students also took a College Survival (SLS) class. The Study Behavior Inventory (SBI) and the Computerized Placement Test (CPT) were administered to the four classes. The SBI was used as a pre- and post-test. The SLS curriculum and classroom time were the same for both groups. However, students in the treatment groups received instruction designed to increase the frequency of effective study behaviors associated with the three factors identified in the SBI, while the students in the control group participated in activities that did not emphasize study behaviors. A series of analysis of covariance procedures were used to analyze four hypotheses. The first three hypotheses proposed that students who were instructed in the use of appropriate study behaviors would score higher on the three factors of the Study Behavior Inventory than those who were not. The fourth hypothesis proposed that a greater proportion of mathematics students who were instructed in the use of appropriate study behaviors would receive a passing grade in their course than students who were in the control group. The four hypotheses were tested at the .05 level of significance. This study revealed that students who received instruction in appropriate study behaviors scored higher in the use of appropriate study behaviors and in mathematics achievement than students who did not. Additional research is needed to investigate whether these effects would persist over time, or be found in subjects other than mathematics.

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Sesquiterpene lactones (SLs) are plant-derived compounds that display anti-cancer effects. Some SLs derivatives have a marked killing effect on cancer cells and have therefore reached clinical trials. Little is known regarding the mechanism of action of SLs. We studied the responses of human cancer cells exposed to various concentrations of dehydroleucodine (DhL), a SL of the guaianolide group isolated and purified from Artemisia douglasiana (Besser), a medicinal herb that is commonly used in Argentina. We demonstrate for the first time that treatment of cancer cells with DhL, promotes the accumulation of DNA damage markers such as phosphorylation of ATM and focal organization of γH2AX and 53BP1. This accumulation triggers cell senescence or apoptosis depending on the concentration of the DhL delivered to cells. Transient DhL treatment also induces marked accumulation of senescent cells. Our findings help elucidate the mechanism whereby DhL triggers cell cycle arrest and cell death and provide a basis for further exploration of the effects of DhL in in vivo cancer treatment models.

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Layered metal oxides provide a single-step route to sheathed superlattices of atomic layers of a variety of inorganic materials, where the interlayer spacing and overall layered structure forms the most critical feature in the nanomaterials’ growth and application in electronics, health, and energy storage. We use a combination of computer simulations and experiments to describe the atomic-scale structure, dynamics and energetics of alkanethiol-intercalated layered vanadium oxide-based nanostructures. Molecular dynamics (MD) simulations identify the unusual substrate-constrained packing of the alkanethiol surfactant chains along each V2O5 (010) face that combines with extensive interdigitation between chains on opposing faces to maximize three-dimensional packing in the interlayer regions. The findings are supported by high resolution electron microscopy analyses of synthesized alkanethiol-intercalated vanadium oxide nanostructures, and the preference for this new interdigitated model is clarified using a large set of MD simulations. This dependency stresses the importance of organic–inorganic interactions in layered material systems, the control of which is central to technological applications of flexible hybrid nanomaterials.

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This paper presents new evidence on the relationships between access to post-secondary education and family background. More specifically, we use the School Leavers Survey (SLS) and the Youth in Transition Survey (YITS)to analyze participation rates first in 1991, and then almost a decade later in 2000. Overall, post-secondary education participation rates rose over this period. However, participation is strongly related to parent’s education, and whereas participation increased for individuals with more highly educated parents (especially those who went to university), they increased rather less, or in some cases (especially for males) declined for those from lower parental education families. The already strong “effect” of parents’ education on post-secondary access became even greater in the 1990’s. Participation rates are also strongly related to family type, but whereas those from two parent families continue to have an advantage over single mother families, the gap generally shrunk in the 1990’s, especially where the mother had university level schooling. We also find a number of interesting trends by province.

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With the development of electronic devices, more and more mobile clients are connected to the Internet and they generate massive data every day. We live in an age of “Big Data”, and every day we generate hundreds of million magnitude data. By analyzing the data and making prediction, we can carry out better development plan. Unfortunately, traditional computation framework cannot meet the demand, so the Hadoop would be put forward. First the paper introduces the background and development status of Hadoop, compares the MapReduce in Hadoop 1.0 and YARN in Hadoop 2.0, and analyzes the advantages and disadvantages of them. Because the resource management module is the core role of YARN, so next the paper would research about the resource allocation module including the resource management, resource allocation algorithm, resource preemption model and the whole resource scheduling process from applying resource to finishing allocation. Also it would introduce the FIFO Scheduler, Capacity Scheduler, and Fair Scheduler and compare them. The main work has been done in this paper is researching and analyzing the Dominant Resource Fair algorithm of YARN, putting forward a maximum resource utilization algorithm based on Dominant Resource Fair algorithm. The paper also provides a suggestion to improve the unreasonable facts in resource preemption model. Emphasizing “fairness” during resource allocation is the core concept of Dominant Resource Fair algorithm of YARM. Because the cluster is multiple users and multiple resources, so the user’s resource request is multiple too. The DRF algorithm would divide the user’s resources into dominant resource and normal resource. For a user, the dominant resource is the one whose share is highest among all the request resources, others are normal resource. The DRF algorithm requires the dominant resource share of each user being equal. But for these cases where different users’ dominant resource amount differs greatly, emphasizing “fairness” is not suitable and can’t promote the resource utilization of the cluster. By analyzing these cases, this thesis puts forward a new allocation algorithm based on DRF. The new algorithm takes the “fairness” into consideration but not the main principle. Maximizing the resource utilization is the main principle and goal of the new algorithm. According to comparing the result of the DRF and new algorithm based on DRF, we found that the new algorithm has more high resource utilization than DRF. The last part of the thesis is to install the environment of YARN and use the Scheduler Load Simulator (SLS) to simulate the cluster environment.

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Planar <110> GaAs nanowires and quantum dots grown by atmospheric MOCVD have been introduced to non-standard growth conditions such as incorporating Zn and growing them on free-standing suspended films and on 10° off-cut substrates. Zn doped nanowires exhibited periodic notching along the axis of the wire that is dependent on Zn/Ga gas phase molar ratios. Planar nanowires grown on suspended thin films give insight into the mobility of the seed particle and change in growth direction. Nanowires that were grown on the off-cut sample exhibit anti-parallel growth direction changes. Quantum dots are grown on suspended thin films and show preferential growth at certain temperatures. Envisioned nanowire applications include twin-plane superlattices, axial pn-junctions, nanowire lasers, and the modulation of nanowire growth direction against an impeding barrier and varying substrate conditions.

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The electronic properties of bilayer graphene strongly depend on relative orientation of the two atomic lattices. Whereas Bernal-stacked graphene is most commonly studied, a rotational mismatch between layers opens up a whole new field of rich physics, especially at small interlayer twist. Here we report on magnetotransport measurements on twisted graphene bilayers, prepared by folding of single layers. These reveal a strong dependence on the twist angle, which can be estimated by means of sample geometry. At small rotation, superlattices with a wavelength in the order of 10 nm arise and are observed by friction atomic force microscopy. Magnetotransport measurements in this small-angle regime show the formation of satellite Landau fans. These are attributed to additional Dirac singularities in the band structure and discussed with respect to the wide range of interlayer coupling models.

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In 2005 the Australian State of Victoria abolished the controversial partial defence of provocation. Part of the impetus for the reforms was to challenge provocation’s victim-blaming narratives and the defence’s tendency to excuse men’s violence against intimate partners. However, concerns were also expressed that these narratives and excuses would simply reappear at the sentencing stage when men who had killed intimate partners were convicted of murder or manslaughter. This paper analyses post-provocation sentencing judgments, reviewing cases over the 10 year period since the reforms in order to determine whether these concerns have been borne out. The analysis suggests that at the level of sentencing outcomes they have not, although at the level of discourse the picture is more mixed. While sentencing narratives continue to reproduce the language of provocation, at the same time, post-provocation sentencing appears to provide opportunities for feminist judging – picking up on the spirit of the reforms – which have been taken up by some judges more than others.

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I takt med att digitala medier har utvecklats under de senaste åren har köpresan för-ändrats till att kunder idag i ett mycket senare skede släpper in leverantörer i dialogen. Marketing Automation adresserar den problembilden och har växt fram som en brygga mellan sälj- och marknadsprocessen. Systemet ger möjlighet att effektivt och automatiserat utveckla leads (potentiell kund). Syftet med denna studie är att undersöka hur Marketing Automation påverkar sälj- och marknadsprocesserna. Vilka förutsättningar krävs för en implementation? Ökar lönsamheten? Vi har därför valt att i det teoretiska ramverket beskriva Marketing Automation och bland annat undersöka om ett införande av Marketing Automation medför att sälj- och marknadsorganisationerna slås samman till en organisatorisk enhet. I studien har vi dessutom kartlagt och beskrivit den moderna köpresan och det som ibland kallas intäktsorganisationen. Vi har funnit att Marketing Automation är relativt outforskat i en svensk kontext. För att utröna om teorin, som i stor utsträckning bygger på internationell litteratur och internationella undersökningar, går att överföra till en svensk kontext har vi valt att genomföra en kvalitativ studie i form av en fallstudie av leverantörer av produkter och tjänster inom området samt företag, med den gemensamma nämnaren att de re-presenterar ett kunskapsintensivt erbjudande och har implementerat lösningar för Marketing Automation. I vår analys finns en samsyn mellan leverantörer och kunder i förutsättningar för ett införande, men vi kan även se hur resultaten divergerar och pekar på implikationer, inte minst avseende måluppfyllnad och samverkan mellan sälj- och marknadsorgani-sationerna. Vår slutsats visar bland annat att Marketing Automation kan leda till uppfyllnad av mjuka värden i företaget men har inte bevisats leda till ökad lönsamhet per automatik. Vi ser lönsamhet och Return on Investment (ROI) som ett område som bör utforskas vidare.