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Lattice thermal conduction in cadmium arsenide

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Chinese Physics B 2022年第11期31卷 424-430页

作者： R F Chinnappagoudra M D Kamatagi n R Patil n S Sankeshwar Department of Physics S.S.Government First Grade CollegeNargund-582207KarnatakaIndia Research Resource Centre Visvesvaraya Technological UniversityBelagavi-590018KarnatakIndia Department of Physics B V B College of Engineering and TechnologyHubliKarnataka 80031India Department of Physics&Electronics CHRIST(Deemed to be University)Bangalore-560029KarnatakaIndia

Lattice thermal conductivity(LTC)of cadmium arsenide(Cd_(3)As_(2))is studied over a wide temperature range(1–400 K)by employing the Callaway *** acoustic phonons are considered to be the major carriers of heat and to be scattered by the sample boundaries,disorder,impurities,and other phonons via both Umklapp and normal phonon *** calculations of LTC of Cd_(3)As_(2)bring out the relative importance of the scattering *** systematic analysis of recent experimental data on thermal conductivity(TC)of Cd_(3)As_(2)samples of different groups,presented in terms of LTC,κL,using a nonlinear regression method,reveals good fits to the TC data of the samples considered for Tnd suggests a value of 0.2 for the Gruneisen *** is,however,found that for T>100 K the inclusion of the electronic component of TC,κe,incorporating contributions from relevant electron scattering mechanisms,is needed to obtain good agreement with the TC data over the wide temperature *** detailed investigations of TC of Cd_(3)As_(2)are required to better understand its suitability in thermoelectric and thermal management devices.

关键词： dirac semimetals Cd_(3)As_(2) thermal conductivity phonon scattering

Assessments on slope instabilities triggered by engineering excavations near a small settlement(Turkey)

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Journal of Mountain Science 2018年第1期15卷 114-129页

作者： TUnCAY Ergün Department of Geological Engineering Hacettepe University

In this study,the mechanisms of slope instabilities triggered by engineering excavations at location of a planned tunnel portal in the northwest region of Turkey were assessed,and stability of the current slopes which has impacts on safety of a settlement(village)and agricultural fields was *** the first stage of the study,in order to identify the geological units and structural properties of the sedimentary rocks in the area,to clarify the mechanisms of instabilities and to characterize discontinuity and rock mass properties field works were *** this content,geotechnical boreholes,geophysical explorations between the boreholes,line surveys to explore discontinuity properties,preparation of slope profiles using topographical techniques and sampling of rock blocks and discontinuity planes were *** the second stage,laboratory tests were carried out on the samples to determine the geomechnical properties of the slope forming materials and ***,back analyses of the instabilities were made to assess the responsible shear strength parameters of the geological units during failures by considering laboratory shear test results *** on the backanalyses of the failures,the strength properties of the slope debris were estimated,and it has been clarified that the residual shear strength properties are the factors controlling slip mechanism along the *** the stability analyses,it is understood that a further instability along the mass or bedding planes in the failed and redesigned area are not expected,if the current slope geometry is not ***,safety factor calculated for the slope in the debris is 1.1 which is well below the recommended value in the *** minimum safety factor for currently stable slopes which were cut at the eastern part of the failed area is 1.22 which is also less than that suggested in *** remedial measures such as mini-pile or slope flattening are suggested af

关键词： Slope instability Back-analysis Remedial measures

Inn/InGan quantum dot electrochemical devices:new solutions for energy and health

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national Science Review 2017年第2期4卷 184-195页

作者： Richard ntzel South China Academy of Advanced Optoelectronics South China Normal University L-nESS and Dipartimento di Scienza dei Materiali Università di Milano-Bicocca

A review is given of the exceptional electrochemical performance of epitaxial Inn/InGan quantum dots(QDs) as photoelectrodes for solar hydrogen generation by water spliting, as biosensor transducers and as anion-selective electrodes, and they are also evaluated as supercapacitor electrodes. he performance is benchmarked against the best performances of other reported materials and nanostructures. A model based on the unique interplay of surface and quantum properties is put forward to understand the boost of catalytic activity and anion selectivity interlinking quantum nanostructure physics with electrochemistry and catalysis. Of equal impact is the direct growth on cheap Si substrates without any bufer layers, allowing novel device designs and integration with Si technology. his makes the Inn/InGan QDs viable, opening up new application ields for Ⅲ-nitride semiconductors.

关键词： quantum dot solar hydrogen biosensor ion-selective electrode supercapacitor Inn InGan

novel approach for evaluation of service reliability for electricity customers

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Science China(Technological Sciences) 2009年第9期52卷 2585-2590页

作者： JIAnG John n School of Electrical and Computer Engineering University of OklahomaNorman OK 73019 USA

Understanding reliability value for electricity customer is important to market-based reliability management. This paper proposes a novel approach to evaluate the reliability for electricity customers by using indifference curve between economic compensation for power interruption and service reliability of electricity. Indifference curve is formed by calculating different planning schemes of network expansion for different reliability requirements of customers, which reveals the information about economic values for different reliability levels for electricity customers, so that the reliability based on market supply demand mechanism can be established and economic signals can be provided for reliability management and enhancement.

关键词： power systems electricity market reliability customers’ outage cost indifference curve

Optimum cutting speed of block-cutting machines in natural stones for energy saving

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Journal of Central South University 2012年第5期19卷 1234-1239页

作者： n.Bilim Department of Mining Engineering Seluk UniversityKonyaTurkey

Energy consumption of block-cutting machines represents a major cost item in the processing of travertines and other natural stones. Therefore, determining the optimum sawing conditions for a particular stone is of major importance in the natural stone-processing industry. An experimental study was carried out utilizing a fully instrumented block-cutter to investigate the sawing performances of five different types of travertine blocks during cutting with a circular diamond saw. The sawing tests were performed in the down-cutting mode. Performance measurements were determined by measuring the cutting speed and energy consumption. Then, specific energy was determined. The one main cutting parameter, cutting speed, was varied in the investigation of optimum cutting performance. Furthermore, some physico-mechanical properties of file travertine blocks were determined in the laboratory. As a result, it is found that the energy consumption （specific energy） of block cutting machines is highly affected by cutting speed. It is determined that specific energy value usually decreases when cutting speed increases. When the cutting speed is higher than the determined value, the diamond saw can become stuck in the travertine block; this situation can be a problem for the block-cutting machine. As a result, the optimum cutting speed obtained for the travertine mines examined is approximately 1.5-2.0 m/min.

关键词： cutting speed travertine block cutting machine specific energy natural stone energy saving

Hybrid Renewable Energy Source Combined Dynamic Voltage Restorer for Power Quality Improvement

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Computer Systems Science & Engineering 2022年第2期40卷 517-538页

作者： n.Kanagaraj Electrical Engineering Department College of EngineeringPrince Sattam Bin Abdulaziz UniversityWadi Aldawasir11991Saudi Arabia

In this paper,the hybrid photovoltaic-thermoelectric generator(PVTEG)combined dynamic voltage restorer(DVR)system is proposed for the power quality disturbances compensation in a single-phase distribution *** stable and precise level of input voltage is essential for the smooth and trouble-free operation of the electrically sensitive loads which are connected at the utility side to avoid system *** this context,the hybrid PV-TEG energy module combined DVR system is proposed in this *** the support of the hybrid energy module,the DVR will perform the power quality disturbances compensation effectively with needed voltage and/or *** the proposed system,the PV and TEG energy sources are connected electrically in series to produce adequate voltage for the DVR operation and the fractional factor-based variable incremental conduction(FFVInC)maximum power point tracking(MPPT)control algorithm is employed to extract the possible maximum power from the PV *** intelligent fuzzy logic controller(FLC)is chosen for implementing the MPPT control *** half-bridge voltage source inverter(VSI)circuit and in-phase voltage compensation technique are used in the DVR for better power quality disturbances *** performance and usefulness of the proposed DVR system are investigated by an extensive simulation study with four different modes of operation,the study results are confirmed that the proposed system promptly identifies the power quality disturbances for ***,the investigation proved that the combined PV and TEG energy module can provide better energy efficiency in converting solar irradiation into electricity.

关键词： Power quality compensation MPPT hybrid energy module DVR

Inclusion of CoTiO_(3) to ameliorate the re/dehydrogenation properties of the Mg–na–Al system

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Journal of Magnesium and Alloys 2024年第3期12卷 1215-1226页

作者： n.A.Ali n.Y.Yusnizam n.A.Sazelee Sami-ullah Rather Haizhen Liu M.Ismail Energy Storage Research Group Faculty of Ocean Engineering TechnologyUniversiti Malaysia Terengganu21030 Kuala NerusTerengganuMalaysia Department of Chemical and Materials Engineering King Abdulaziz UniversityP.O.Box80204Jeddah 21589Saudi Arabia Guangxi novel Battery Materials Research Center of Engineering Technology School of Physical Science and TechnologyGuangxi UniversityNanning 530004China State Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite Structures Nanning 530004China

For the first time,the MgH_(2)–naAlH_(4)(ratio 4:1)destabilized system with CoTiO_(3) addition has been *** CoTiO_(3)-doped MgH_(2)–naAlH_(4) sample begins to dehydrogenate at 130℃,which is declined by 40℃ compared to the undoped MgH_(2)–naAlH_(4).Moreover,the de/rehydrogenation kinetics characteristics of the CoTiO_(3)-doped MgH_(2)–naAlH_(4) were greatly *** the inclusion of CoTiO_(3),the MgH_(2)–naAlH_(4) composite absorbed 5.2 wt.%H_(2),higher than undoped MgH_(2)–naAlH_(4).In the context of dehydrogenation,the CoTiO_(3)-doped MgH_(2)–naAlH_(4) sample desorbed 2.6 wt.%H_(2),almost doubled compared to the amount of hydrogen desorbed from the undoped MgH_(2)–naAlH_(4) *** activation energy obtained by the Kissinger analysis for MgH_(2) decomposition was significantly lower by 35.9 kJ/mol than the undoped MgH_(2)–naAlH_(4) *** reaction mechanism demonstrated that new phases of MgCo and AlTi_(3) were generated in situ during the heating process and are likely to play a substantial catalytic function and be useful in ameliorating the de/rehydrogenation properties of the destabilized MgH_(2)–naAlH_(4) system with the inclusion of CoTiO_(3).

关键词： Destabilize system Magnesium hydride Sodium alanate Hydrogen storage Additive.

Observation of the hyperfine structure and anticrossings of hyperfine levels in the luminescence spectra of LiYF4:Ho3+

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Light(Science & Applications) 2022年第9期11卷 2155-2165页

作者： KIRILL n.BOLDYREV BORIS Z.MALKIn MARInA n.POPOVA Institute of Spectroscopy Russian Academy of SciencesTroitskMoscow 108840Russia Kazan Federal University Kazan 420008Russia

Resolved hyperfine structure and narrow inhomogeneously broadened lines in the optical spectra of a rare-earth-doped crystal are favorable for the implementation of various ***,a well-resolved hyperfine structure in the photoluminescence spectra of LiYF4:Ho single crystals and the anticrossings of hyperfine levels in a magnetic field are demonstrated using a self-made setup based on a Bruker 125HR high-resolution Fourier *** is the first observation of the resolved hyperfine structure and anticrossing hyperfine levels in the luminescence spectra of a *** narrowest spectral linewidth is only 0.0022 *** fact together with a large value of the magnetic g factor of several crystal-field states creates prerequisites for developing magnetic field sensors,which can be in demand in modern quantum information technology devices operating at low *** small random lattice strains characterizing the quality of a crystal can be detected using anticrossing points.

关键词： spectra luminescence hyperfine

The digital‘connected’earth:open technology for providing location-based services on degraded communication environments

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International Journal of Digital Earth 2018年第8期11卷 761-782页

作者： Ramón Piedrafita Rubén Béjar Rubén Blasco Alvaro Marco F.Javier Zarazaga-Soria Aragón Aragón Institute of Engineering Research Universidad de ZaragozaZaragozaSpain

n the current world,it is easy to listen that everybody and everything is *** this connected world,the concept of location-based services has grown in order to provide digital services in everyplace and at every ***,this is not 100%true because the connection is not guaranteed for many people and in many *** are the Degraded Communications Environments(DCE),environments where the availability of high-speed communications is not guaranteed in at least the 75%of the *** paper works over the experience of a previous work in developing light protocols that do not need broadband for *** work provides an extension of these protocols for the inclusion of mobile devices as elements of the communication process and a set of libraries to allow the development of applications in *** work done has involved the development of two frameworks:an Android framework that makes the incorporation of Android devices easier and a server-based framework that provides the server side for the development of the referred applications.A use case that uses these two frameworks has been ***,all technology developed is available throw a public Git repository.

关键词： Location-based services degraded communications environments open technology