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Biaxial versus uniaxial strain tuning of single-layer MoS_(2)

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Nano Materials Science 2022年第1期4卷 44-51页

作者： felix Carrascoso Riccardo Frisenda Andres Castellanos-Gomez Materials Science Factory Instituto de Ciencia de Materiales de Madrid(ICMM-CSIC)28049Madrid Spain

Strain engineering has arisen as a powerful technique to tune the electronic and optical properties of twod imensional semiconductors like molybdenum disulfide(MoS_(2)).Although several theoretical works predicted that biaxial strain would be more effective than uniaxial strain to tune the band structure of MoS_(2),a direct experimental verification is still missing in the *** we implemented a simple experimental setup that allows to apply biaxial strain through the bending of a cruciform polymer *** used the setup to study the effect of biaxial strain on the differential reflectance spectra of 12 single-layer MoS_(2)flakes finding a redshift of the excitonic features at a rate between-40 meV/%and-110 meV/%of biaxial *** also directly compare the effect of biaxi al and uniaxial strain on the same single-layer MoS_(2)finding that the biaxial strain gauge factor is 2.3 times larger than the uniaxial strain one.

关键词： finding layer gauge

Analysis of pneumatic atomizer spray profiles

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Particuology 2016年第6期14卷 80-85页

作者： Walter Schafer Simon Rosenkranz felix Brinckmann Cameron Tropea AOM-Systems GmbH Flughafenstrasse 15 64347 Griesheim Germany LacTec GmbH Otto-Hahn-Strasse 6-8 63110 Rodgau Germany Institute of Fluid Mechanics and Aerodynamics Technische Universitat Darmstadt Alarich-Weiss-Strasse 10 64287 Darmstadt Germany Graduate School of Computational Engineering Technische Universitat Darmstadt Dolivostrasse 15 64287 Darmstadt Germany

Our objective is to analyze the atomization processes of a pneumatic atomizer by measuring the size and velocity distributions of droplets in a liquid paint spray. The droplet size and velocity distributions have been determined at different axial positions in the spray; a mathematical description of how these quan- tities vary throughout the spray is then proposed. Additionally, the relative number density of droplets and the relative local mass flux are estimated.

关键词： Pneumatic atomizer Spray Measurement Droplet size profile Droplet velocity profile Time-shift

Towards an Internet-like Power Grid

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Journal of Modern Power Systems and Clean Energy 2022年第1期10卷 1-11页

作者： Iasonas Kouveliotis-Lysikatos Nikos Hatziargyriou Yanli Liu felix Wu Department of Electrical Engineering and Computer Science KTH-Royal Institute of TechnologyTeknikringen 3310040StockholmSweden School of Electrical and Computer Engineering National Technical University of Athens15773 AthensGreece School of Electrical and Information Engineering Tianjin UniversityTianjin300072China Department of Electrical and Electronic Engineering The University of Hong KongHong KongChina Department of Electrical Engineering and Computer Sciences University of CaliforniaBerkeleyCA 94720USA

The great challenges faced by modern power systems require a fresh look at the conventional operation paradigm. The significant challenges faced by modern power systems require an innovative method for the conventional operation paradigm. We claim that the decarbonization of the power grid and extensive electrification of numerous sectors of human activity can only be fostered by a self-adaptable and smart power grid that manifests similar qualities to those of the Internet. The Internet is constructed on a layered architecture that facilitates technology innovations and its intelligence is distributed throughout a hierarchy of networks. In this paper, the fundamental differences between the network data flows and power flows are examined, and the basic requirements for an innovative operation paradigm are highlighted. The current power grid is operated in a highly inflexible, centralized manner to meet increased security goals. A new highly flexible, distributed architecture can be realized by distributing the operation responsibility in smaller areas or even in grid components that can make autonomous decisions. The characteristics of such a power grid are presented, and the key features and advances for the on-going transition to a sustainable power system are identified. Finally, a case study on distributed voltage control is presented and discussed.

关键词： Smart grid Internet distributed intelligence decentralized architecture

Strain engineering in single-,bi-and tri-layer MoS_(2),MoSe_(2),WS_(2)and WSe_(2)

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Nano Research 2021年第6期14卷 1698-1703页

作者： felix Carrascoso Hao Li Riccardo Frisenda Andres Castellanos-Gomez Materials Science Factory Instituto de Ciencia de Materiales de MadridConsejo Superior de Investigaciones Cientificas28049MadridSpain

Strain is a powerful tool to modify the optical properties of semiconducting transition metal dichalcogenides like MoS_(2),MoSe_(2),WS_(2) and WSe_(2).In this work we provide a thorough description of the technical details to perform uniaxial strain measurements on these two-dimensional semiconductors and we provide a straightforward calibration method to determine the amount of applied strain with high *** then employ reflectance spectroscopy to analyze the strain tunability of the electronic properties of single-,bi-and tri-layer MoS_(2),MoSe_(2),WS_(2) and WSe_(2).Finally,we quantify the flake-to-flake variability by analyzing 15 different single-layer MoS_(2) flakes.

关键词： two-dimensional(2D)materials transition metal dichalcogenides strain engineering band gap differential reflectance

Security of the Internet Transactions

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计算机科学 2002年第Z1期29卷 83-84,72页

作者： felix Musau College of Information Science & Engineering Central South University Changsha410083

The new generation of networked business solutions brings legacy data and applications to the world wide Web, and lets companies redefine internal and external business processes. The present need for internet transaction has forced many business to adopt the internet forms of distribution of its business items. This has threatened security, hence needs to be given a key priority. This paper alights the key areas on how to protect the information we transact on the internet. It also aims at improving the security of our data and the computers we use to access this data.

关键词： Authentication Cryptography Web secure Transaction server COM

Assessing the influence of harvesting intensities on structural diversity of forests in south-west Germany

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Forest Ecosystems 2019年第3期6卷 249-260页

作者： felix Storch Gerald Kadler Jürgen Bauhus Chair of Silviculture University of FreiburgD-79085 FreiburgGermany Department of Biometry Forest Research Institute of Baden-WürttembergD-79100 FreiburgGermany

Background: To increase ecosystem resilience and biodiversity, the maintenance and improvement of structural and compositional diversity of forests has become an important goal in forest management for many forest owners and jurisdictions. At the same time, future harvesting intensity (HI) may increase to meet the demand for woody biomass by an increasing bioeconomy sector. Yet, the influence of HI on forest structural diversity is largely unknown. Here, we address this issue by analyzing the relationship between HI and structural diversity based on large-scale national forest inventory (NFI) data, where the latter is quantified using a previously developed Forest Structure Index and HI is expressed as wood volume removal during the period 2002-2012 for the same inventory plots. Results: Our results show a surprisingly small impact of harvesting intensity on changes in structural diversity for most of the analysed types of forests. Only intense harvesting (> 80%-90% of initial growing stock) led to a significant reduction in structural diversity. At low to moderate HI most aspects of structural diversity were positively influenced. Only the quadratic mean DBH and the volume of large trees (≥ 40 cm DBH) were substantially negatively influenced at HI > 60% and 70% of initial growing stock, respectively. Conclusions: In several forest types, HI could be increased without a reduction in overall structural diversity. Hence, structural diversity in these selectively managed forests appears to be a very resistant forest property in relation to HI. Other indicators at stand and landscape scale may be needed to adjust levels of HI that are suited to maintain forest biodiversity.

关键词： Large-scale inventory Structural diversity index Harvesting intensity Changes in structural diversity

Microstructure and Corrosive Property of Ni-P/nano-CeO_2 Coating Electrolessly Prepared in Acidic Condition

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Journal of Wuhan University of Technology(Materials Science) 2010年第5期25卷 734-737页

作者：靳惠明 A felix M Aroyave College of Mechanical Engineering Yangzhou University College of Materials Engineering National University of Antioquia Medellin 23715 Colombia

Electroless Ni-P/nano-CeO2 composite coating was prepared in acidic condition, and its microstructure and corrosive property were compared with its CeO2-free counterpart. Scanning electronic microscopy （SEM）, transmission electronic microscopy （TEM） and differential scanning calorimeter （DSC） were used to examine surface morphology and microstructure of the coating. Aqueous corrosion was done in 3%NaCl＋5%H2SO4 solution and high temperature oxidation was done at 750 ℃ in air. The results showed that Ni-P coating had partial amorphous structure mixed with nano-crystals, while the Ni-P/CeO2 coating had perfect amorphous structure. At high temperature, Ni3P precipitation and Ni crystallization took place in both coatings at different temperatures. Aqueous corrosion property and high temperature oxidation property of the composite coating were remarkably improved due to the coating＇s microstructure change and the rare earth doping effect. During the co-deposition process, some Ce^n＋（n=3, 4） ions may be adsorbed to metal/solution interface and hinder nickel deposition. Ni-P/CeO2 coating＇s perfect amorphous structure results from the hindered crystal-typed deposition of nickel and the promoted deposition of phosphorous.

关键词： microstructure composite coating electroless plate ceria corrosion

Rare earth effect of yttrium on formation and property of Cr2O3 oxide film formed on Co-Cr binary alloy

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Progress in Natural Science:Materials International 2006年第1期16卷 72-77页

作者： felix A. Congrado AROYAVE M. Hayara College of Materials Science and Engineering National University of Antiuquia Medellin 23715Colombia

The isothermal oxidizing kinetics of Co-40Cr alloy and its yttrium ion-implanted samples were studied at 1000 ℃ in air by thermal-gravity analysis (TGA). Scanning electronic microscopy (SEM) was used to examine the Cr2O3 oxide film's morphology after oxidation. Secondary ion mass spectrum (SIMS) method was used to examine the binding energy change of chromium caused by Y-doping and its influence on formation of Cr2O3 film. Acoustic emission (AE) method was used in situ to monitor the cracking and spalling of oxide films formed on both samples during oxidizing and subsequent air-cooling stages. Theoretical model simulating the film fracture process was proposed to analyze the acoustic emission spectrum both on time domain and on AE-event number domain. It is found that yttrium ion-implantation can remarkably reduce the isothermal oxidizing rate of Co-40Cr and improve the anti-cracking and anti-spalling properties of Cr2O3 oxide film. Reasons for the improvement are mainly that the implanted yttrium can reduce the grain size of Cr2O3 oxide, increase the high temperature plasticity of oxide film, and remarkably reduce the number and size of Cr2O3/Co-40Cr interfacial defects.

关键词： interface binding energy acoustic emission oxidation yttrium.

Scoping review: obese elderly women with breast cancer and physical activity/exercise

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Global Health Journal 2022年第3期6卷 129-135页

作者： Mark Stephan felix Department of Society and Health Faculty of Social Sciences and HumanitiesMahidol UniversitySalayaNakhon Pathom 73170Thailand

Objective:Obesity and breast cancer(BC)are diseases of concern,especially within the context of an aging *** scoping review is aimed at mapping out the literature on the subject of elderly women(EW)with breast cancer,obesity and physical activity/exercise(PAE)to identify gaps in the present extant literature,and to suggest directions for future *** sources:A total of four articles were finalized from an initial 2905 articles found via searches on the Annals of Internal Medicine by American College of Physicians(ACP)^(TM),BioMed Central(BMC)^(TM),BMJ Journals^(TM),Journal of the American Medical Association(JAMA)^(TM),PubMed^(TM),SAGE^(TM),ScienceDirect^(TM),SpringerLink(e-journals)^(TM),Taylor and Francis Online^(TM),and Wiley Online Library^(TM) ***:Recognized structural frameworks for scoping reviews were utilized to guide the methodology and technical aspects of this *** extraction was conducted via a charting ***:Research gaps identified include a paucity in research on the subject of obesity and breast cancer among elderly women;there is a limitation of the types of methodologies used in the research on this subject indicating vast opportunities for future studies using different methodologies;lack of use of the alternative types of physical activity and exercise such as Tai Chi,Qigong and Yoga;lack of focus on the older elderly population;and areas of social support from family and friends for obese elderly with breast cancer to engage in physical activity and ***:Future research would address the urgent need within academia to address the research gap of PAE and *** research should use a diverse range of both quantitative and qualitative research methodologies,while including eastern exercise regimens such as Tai Chi,Qigong and Yoga as a means of studying PAE among ***,future research may focus on the“old elderly”as a demographic group of study as well as how social suppo

关键词： Obesity Breast cancer Elderly Physical activity Exercise