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Assessing conservation practices in Amalacaxco Gorge (Izta-Popo National Park, Central mexico) using fallout 137Cs and Optically Stimulated Luminescence (OSL)

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Journal of mountain Science 2018年第3期15卷 447-460页

作者： mUNOZ-SALINAS e CASTILLO m Departamento de Geología Regional Universidad Nacional Autónoma de México Ciudad UniversitariaCiudad de MexicoMexico Laboratorio Nacional de Geoquimicay mineralogia Ciudad Universitaria Ciudad de Mexico Mexico

This study aims to assess conservation practices in Izta-Popo National Park(Central mexico) by evaluating the.m.chanisms of sediment transfer. We applied a methodology based on fallout ^(137)Cs and optically stimulated luminescence(OSL) analysis. This was tested in the upper catchment of Amalacaxco Gorge, selected for being one of the sectors of the park in which man-made actions have been implemented in last decades to favor forest growth in the alpine grassland and to reduce the effect of water runoff. We quantified the ^(137)Cs activity using gamma and beta spectrometry of fine sediment grains extracted from the surface of parcels of 0.4 m2 in areas of natural forest, natural alpine grassland, alpine grassland with conservation practices, ravines and trails. In general, ^(137)Cs values increases as local slope decreases as it was expected. The natural forest is the.m.st stable area in te.m. of soil erosion and sediment accumulation and, mean ^(137)Cs activity was taken as reference to assess cumulative zones, with higher ^(137)Cs values and erosive, with lower. We found that trails are accumulative surfaces but in other areas, erosion predominates. man-made ditches, trenches and afforestation in the alpine grassland have higher ^(137)Cs values than thenatural grassland, which indicates that conservation practices are limiting the sediment transfer from hillslopes to channels, however, soil retention is less than in the natural grassland. Additionally, we evaluated the luminescence(OSL) values obtained from samples extracted from the sediment transported in ravines that are cutting into different sectors of the study area to assess the grade of resetting of fluvial materials. These luminescence results indicated that the sediment transported in ravines that are cutting into the natural forest and alpine grassland is bleached more efficiently than the sediment transported in the alpine grassland with conservation practices. Results of fallout ^(137)Cs and luminesce

关键词： Sediment transfer Soil erosion Natural protected areas Alpine grassland Caesium-137 Optically stimulated luminescence

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看得见风景的房间

efficient Nanostructuring of Isotropic Gas-Atomized mnAl Powder by Rapid milling(30s)

作者： e.m.·福斯特(e.m. Forster)

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engineering 2020年第2期6卷 173-177页

作者： J.Rial e.m.Palmero A.Bollero Division of Pe.m.nent magnets and Applications IMDEA NanoscienceCampus Universidad Autonoma de MadridMadrid 28049Spain

An unprecedentedly short milling time of 30 s was applied to gas-atomized mnAl powder in order to develop pe.m.nent magnet properties and,in particular,*** is shown that such a short processing time followed by annealing results in efficient nanostructuring and controlled phase *** defects resulting from the.m.crostrain induced during milling,together with the creation of the bphase during post-annealing,act as pinning centers resulting in an enhanced *** study shows the importance of finding a balance between the formation of the ferromagnetic s-mnAl phase and the bphase in order to establish a compromise between magnetization and coercivity.A coercivity as high as 4.2 kOe(1 Oe=79.6 A·m^-1)was obtained after milling(30 s)and annealing,which is comparable to values previously reported in the literature for milling times exceeding 20 *** reduction of the postannealing temperature by 75℃ for the as-milled powder and a 2.5-fold increase in coercivity,while.m.intaining practically unchanged the remanence of the annealed gas-atomized material,opens a new path for the synthesis of isotropic mnAl-based powder.

关键词： Pe.m.nent magnets(Pms) Nanostructuring Phase transformation mnAl Gas atomization Ball milling

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强力集团作曲家论民间音乐

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enhanced quantum resources via two distant atom-cavity systems under the influence of atomic dissipation

1962年

作者：（苏）戈尔捷耶娃 e.m.编孙静云译

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Communications in Theoretical Physics 2024年第2期76卷 62-73页

作者： m Setodeh Kheirabady m K Tavassoly m Rafeie e Ghasemian Laser and Optics Group Faculty of PhysicsYazd UniversityYazd 89195-741Iran Department of electrical engineering Faculty of Intelligent Systems Engineering and Data SciencePersian Gulf UniversityBushehrIran

Quantum resources such as entanglement and coherence are the holy grail for modern quantum technologies. Although the unwanted environmental effects tackle quantum information processing tasks, suprisingly these key quantum resources may be protected and even enhanced by the implementation of some special hybrid open quantum systems. Here, we aim to show how a dissipative atom-cavity-system can be accomplished to generate enhanced quantum *** do so, we consider a couple of dissipative cavities, where each one contains two effective two-level atoms interacting with a single.m.de cavity field. In practical applications, a classical laser field may be applied to drive each atomic subsystem. After driving the system, a Bell-state.m.asurement is performed on the output of the system to quantify the entanglement and coherence. The obtained results reveal that the remote entanglement and coherence between the atoms existing inside the two distant cavities are not only enhanced, but can be stabilized, even under the action of dissipation. In contrast, the local entanglement between two atoms inside each dissipative cavity attenuates due to the presence of unwanted environmental ***, the local coherence.m.y show the same behavior as the remote ***, the system provides the steady state entanglement in various interaction regimes,particularly in the strong atom-cavity coupling and with relatively large detuning. more interestingly, our numerical analyses demonstrate that the system may show a memory effect due to the fact that the death and revival of the entanglement take place during the interaction. Our proposed model may find potential applications for the implementation of long distance quantum networks. In particular, it facilitates the distribution of quantum resources between the nodes of large-scale quantum networks for secure communication.

关键词： remote entanglement and coherence atomic dissipation steady state entanglement Bell-statemeasurement

Faddeev calculations on lambda hypertriton with potentials from Gel'fand–Levitan–marchenko theory

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Communications in Theoretical Physics 2020年第10期72卷 119-124页

作者： e F meoto m L Lekala Department of Physics University of South AfricaPrivate Bag X61710 JohannesburgSouth Africa

effective lambda-proton and lambda-neutron potentials,restored from theoretical scattering phases through Gel'fand–Levitan–marchenko theory,are tested on a lambda hypertriton through three-body *** lambda hypertriton is treated as a three-body system consisting of lambda-proton,lambda-neutron and proton–neutron *** energy and root mean square radius are computed for the ground state of lambda hypertriton(Jp=12+).In coordinate space,the dynamics of the system is described using a set of coupled hyperradial equations obtained from the differential Faddeev *** solving the eigenvalue problem derived from this set of coupled hyperradial equations,the binding energy and root mean square.m.tter radius computed are found to be-2.462 meV and 7.00 fm,*** potentials are also shown to display a satisfactory convergence behaviour.

关键词： lambda-nucleon potential lambda-proton potential lambda-neutron potential lambda hypertriton Faddeev equations hyperspherical method

exploring the band structure of Wurtzite InAs nanowires using photocurrent spectroscopy

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Nano Research 2020年第6期13卷 1586-1591页

作者： Seyyedesadaf Pournia Samuel Linser Giriraj Jnawali Howard e.Jackson Leigh m.smith Amira Ameruddin Philippe Caroff Jennifer Wong-Leung Hark Hoe Tan Chennupati Jagadish Hannah J.Joyce Department of Physics University of CincinnatiCincinnatiOH45221-0011USA Department of electronic materials engineering Research School of PhysicsThe Australian National UniversityCanberraACT2601Australia Department of engineering University of Cambridge9 JJ Thomson AvenueCambridgeCB30FAUK

Nano Research volume We use polarized photocurrent spectroscopy in a nanowire device to investigate the band structure of hexagonal Wurtzite *** of optical transitions between four valence bands and two conduction bands are observed which are consistent with the symmetries expected from group *** ground state transition energy identified from photocurrent spectra is seen to be consistent with photoluminescence emitted from a cluster of nanowires from the same growth *** the energies of the observed bands we dete.m.ne the spin orbit and crystal field energies in Wurtzite *** information is vital to the development of crystal phase engineering of this important III-V semiconductor.

关键词： nanowires Wurtzite InAs photocurrent measurement optical selection rules energy band structure

mOLeCULAR ORGANIZATION OF POLY（N-eTHYL-4-VINYLPYRIDINIUm）-DODeCYL SULFATe COmPLeXeS:eFFeCT OF POLYmeRIZATION DeGRee,TemPeRATURe AND CONCeNTRATION.

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MOLECULAR ORGANIZATION OF POLY（N-ETHYL-4-VINYLPYRIDINIUM）-...

mathematical modeling for dynamic stability of sandwich be.m.with variable.m.chanical properties of core

40th IUPAC Congress

作者： m.V. Otdelnova e.m. Ivleva J.A. Zakharova Department of Chemistry Moscow State UniversityMoscow 119992Russia Department of Chemistry Moscow State UniversityMoscow 119992Russia Department of Chemistry Moscow State UniversityMoscow 119992Russia

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Applied mathematics and mechanics(english edition) 2016年第10期37卷 1361-1374页

作者： m.GRYGOROWICZ e.m.GNUCKA-BLANDZI Institute of Applied mechanics Poznan University of Technology Institute of mathematics Poznan University of Technology

The paper is devoted to mathematical modelling of static and dynamic stability of a simply supported three-layered be.m.with a metal foam core. mechanical properties of the core vary along the vertical direction. The field of displacements is for- mulated using the classical broken line hypothesis and the proposed nonlinear hypothesis that generalizes the classical one. Using both hypotheses, the strains are dete.m.ned as well as the stresses of each layer. The kinetic energy, the elastic strain energy, and the work of load are also dete.m.ned. The system of equations of motion is derived using Hamilton＇s principle. Finally, the system of three equations is reduced to one equation of motion, in particular, the.m.thieu equation. The Bubnov-Galerkin method is used to solve the system of equations of motion, and the Runge-Kutta method is used to solve the second-order differential equation. Numerical calculations are done for the chosen family of be.m.. The critical loads, unstable regions, angular frequencies of the be.m. and the static and dynamic equilibrium paths are calculated analytically and verified numerically. The results of this study are presented in the forms of figures and tables.

关键词： mathematical modelling dynamic stability metal foam core with variable.m.chanical property static and dynamic equilibrium path angular frequency