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Land use effects on climate in China as simulated by a regional climate model

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Science China Earth Sciences 2007年第4期50卷 620-628页

作者： j.S.PAL f.GIORGI The Abdus Salam International Center for Theoretical Physics Trieste 34100 Italy

A regional climate model (RegCM3) nested within ERA40 re-analyzed data is used to investigate the climate effects of land use change over China. Two 15-year simulations (1987―2001), one with current land use and the other with potential vegetation cover without human intervention, are conducted for a domain encompassing China. The climate impacts of land use change are assessed from the difference between the two simulations. Results show that the current land use (modified by anthropogenic ac- tivities) influences local climate as simulated by the model through the reinforcement of the monsoon circulation in both the winter and summer seasons and through changes of the surface energy budget. In winter, land use change leads to reduced precipitation and decreased surface air temperature south of the Yangtze River, and increased precipitation north of the Yangtze River. Land use change signifi- cantly affects summer climate in southern China, yielding increased precipitation over the region, de- creased temperature along the Yangtze River and increased temperature in the South China area (south-end of China). In summer, a reduction of precipitation over northern China and a temperature rise over Northwest China are also simulated. Both daily maximum and minimum temperatures are affected in the simulations. In general, the current land use in China leads to enhanced mean annual precipitation and decreased annual temperature over south China along with decreased precipitation over North China.

关键词： land use China simulation regional climate model regional climate change

Interfacial effects in electromagnetic coupling within piezoelectric phononic crystals

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Acta Mechanica Sinica 2009年第1期25卷 95-99页

作者： f. j. Sabina A.B.Movchan Instituto de Investigaciones en Matematicas Aplicadas yen Sistemas Universidad Nacional Autónoma de México Department of Mathematical Sciences University of Liverpool

In this paper, we discuss waves in piezoelectric periodic composite, with the emphasis on the connection between the electromechanical coupling and the effects of dispersion of Bloch-floquet waves. A particular attention is given to structures containing interfaces between dissimilar media and localization of the electrical fields near such interfaces.

关键词： Piezoelectric periodic composites Interfaces Dispersion of Bloch-floquet waves

Prevention of gob ignitions and explosions in longwall mining using dynamic seals

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International journal of Mining Science and Technology 2017年第6期27卷 999-1003页

作者： Brune jürgen f. Saki Saqib A. Department of Mining Engineering Colorado School of Mines CO 80401 USA Aldea Services LLC Frederick MD 21704 USA

Most, if not all longwall gob areas accumulate explosive methane-air mixtures that pose a deadly hazard to miners. Numerous mine explosions have originated from explosive gas zones(EGZs) in the longwall gob. Since 2010, researchers at the Colorado School of Mines(CSM) have studied EGZ formation in longwall gobs under two long-term research projects funded by the National Institute for Occupational Safety and Health. Researchers used computational fluid dynamics along with in-mine measurements. for the first time, they demonstrated that EGZs form along the fringe areas between the methane-rich atmospheres and the fresh air ventilated areas along the working face and present an explosion and fire hazard to mine workers. In this study, researchers found that, for progressively sealed gobs, a targeted injection of nitrogen from the headgate and tailgate, along with a back return ventilation arrangement, will create a dynamic seal of nitrogen that effectively separates the methane zone from the face air and eliminates the EGZs to prevent explosions. Using this form of nitrogen injection to create dynamic seals should be a consideration for all longwall operators.

关键词： Mine explosions face ignitions Coal mining Longwall mining Methane

Variational Calculus With Conformable fractional Derivatives

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IEEE/CAA journal of Automatica Sinica 2017年第2期4卷 340-352页

作者： Matheus j.Lazo Delfim f.M.Torres Instituto de Matemática Estatística e Física-FURG Center for Research and Development in Mathematics and Applications (CIDMA) Department of MathematicsUniversity of Aveiro

Invariant conditions for conformable fractional problems of the calculus of variations under the presence of external forces in the dynamics are studied. Depending on the type of transformations considered, different necessary conditions of invariance are obtained. As particular cases, we prove fractional versions of Noether's symmetry theorem. Invariant conditions for fractional optimal control problems, using the Hamiltonian formalism, are also investigated. As an example of potential application in Physics, we show that with conformable derivatives it is possible to formulate an Action Principle for particles under frictional forces that is far simpler than the one obtained with classical fractional derivatives.

关键词： Conformable fractional derivative fractional calculus of variations fractional optimal control invariant variational conditions Noether’s theorem

Taxonomic and phylogenetic composition show biotic resistance to exotic invasion in acid seep springs

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Ecological Processes 2021年第1期10卷 77-88页

作者： David f.Barfknecht David j.Gibson School of Biological Sciences Southern Illinois University–CarbondaleCarbondaleIL 62901-6509USA

Background:few studies have incorporated the evolutionary insights provided by analysis of phylogenetic structure along with community composition to assess the effects of exotic invasion on freshwater ***,we assess the taxonomic and phylogenetic relationships among acid seep springs to investigate the potential homogenization or resistance of communities due to invasion of an exotic ***:Multivariate community analyses indicated differences in community and phylogenetic composition and dispersion among acid seep springs,associated with gradients in soil moisture,canopy cover,and phylogenetic *** contrast,univariate analyses showed differences in taxonomic diversity but not phylogenetic diversity among acid seep ***:Despite exotic invasion,individual acid seep springs remained taxonomically and phylogenetically distinct from each *** and phylogenetic diversity metrics revealed different aspects of composition,reinforcing the importance of including both in analyses of plant communities for understanding community assembly following exotic invasion and for management *** acid seep springs,taxonomic and phylogenetic composition appear to be driven more through environmental filtering by light and moisture than by the competitive effects following invasion of an exotic grass in support of Elton’s biotic resistance hypothesis.

关键词： Acid seep springs Diversity Community Phylogenetics Exotic invasion Environmental filtering NMDS Unifrac Vector analysis

Catalytic performance of zinc-supported copper and nickel catalysts in the glycerol hydrogenolysis

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journal of Energy Chemistry 2020年第3期29卷 185-194页

作者： R.j.Chimentao B.C.Miranda D.Ruiz f.Gispert-Guirado f.Medina j.Llorca j.B.O.Santos Physical Chemistry Department Faculty of Chemical SciencesUniversity of ConcepcionCasilla 160-CConcepcionChile Chemical Engineering School Universidad de Costa Ric1San Jose 2060Costa Rica Scientific Resources Service Universitat Rovira i VirgiliTarragona 43007Spain Department of Chemical Engineering Universitat Rovira i VirgiliTarragona 43007Spain Department of Chemical Engineering Barcelona Research Center in Multiscale Science and EngineeringInstitute of Energy TechnologiesUniversitat Politècnica de Cataluny1EEBE08019 Barcelon1Spain Department of Chemical Engineering Universidade Federal de Sao Carlos(UFSCAR)Sao CarlosBrazil

Gas-phase catalytic conversion of glycerol to value added chemicals was investigated over zinc-supported copper and nickel *** addition of aluminum in the support was also investigated in glycerol conversion and the results indicate an increase in the acidity and adsorption capacity for both copper and nickel *** and XRD analysis revealed Ni Zn alloy formation in the Ni/ZnO *** XRD patterns of the prepared Zn Al mixed oxide catalysts show the presence of Gahanite phase(ZnAl2O4).In addition,H2 chemisorption and TPR results suggest a strong metal-support interactions(SMSI)effect between Ni and Zn O *** supports Zn O and ZnAl(Zn/Al=0.5)were investigated in the glycerol conversion and they did not present *** supported on ZnO and ZnAl mixed oxide(Zn/Al=0.5)was active towards hydroxyacetone *** was active in the hydrogenolysis of glycerol both for C–C and C–O bonds cleavage of glycerol producing *** metal-support interactions(SMSI)between Ni and ZnO has a remarkable suppression effect on the methanation activity during the glycerol conversion.

关键词： Glycerol Hydrogenolysis Dehydration Hydroxyacetone Copper Nickel Catalyst

A dive into spectral inference networks: improved algorithms for self-supervised learning of continuous spectral representations

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Applied Mathematics and Mechanics(English Edition) 2023年第7期44卷 1199-1224页

作者： j.WU S.f.WANG P.PERDIKARIS Graduate Group in Applied Mathematics and Computational Science University of Pennsylvania PhiladelphiaPA 19104U.S.A. Department of Mechanical Engineering and Applied Mechanics University of Pennsylvania PhiladelphiaPA 19104U.S.A.

We propose a self-supervising learning framework for finding the dominant eigenfunction-eigenvalue pairs of linear and self-adjoint *** represent target eigenfunctions with coordinate-based neural networks and employ the fourier positional encodings to enable the approximation of high-frequency *** formulate a self-supervised training objective for spectral learning and propose a novel regularization mechanism to ensure that the network finds the exact eigenfunctions instead of a space spanned by the ***,we investigate the effect of weight normalization as a mechanism to alleviate the risk of recovering linear dependent modes,allowing us to accurately recover a large number of *** effectiveness of our methods is demonstrated across a collection of representative benchmarks including both local and non-local diffusion operators,as well as high-dimensional time-series data from a video *** results indicate that the present algorithm can outperform competing approaches in terms of both approximation accuracy and computational cost.

关键词： spectral learning partial differential equation(PDE) neural network slow features analysis

Oxidation and Coatings for Power Generation： New Super Ultra Critical Steam Turbines

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中国腐蚀与防护学报 2009年第4期29卷 318-319页

作者： f. j. PEREZ Grupo de Investigacion de Ingenieria de Superficies y Materiales Nanoestructurados U. C. M. N°910627 facultad de Ciencias Quimicas Universidad Complutense de Madrid. 28040 Madrid Spain

The steels with chromium contents between 9%and 12%wt are used for power plants with advanced steam oxidation *** present good creep properties as 9%Cr steels and good oxidation resistance,at the temperatures range between 500℃～600℃.In the last years numerous investigation in development of coatings has been realized with the aim the protected them against the oxidation in order to allow operation of steam turbines at 650℃.In this study,Al-Hf protective coatings were deposited by CVD-fBR on ferritic steel HCM-12A followed by a diffusion heat treatment,have shown to be protective at 650℃under steam for at least 3000 hours of laboratory steam exposure under atmospheric *** and composition of coatings were characterized by different techniques, such as scanning electron microscopy(SEM),electron probe microanalysis,and X-ray diffraction(XRD). On the other hand,volatile species by mass spectrometry(MS) and thermogravimetric measurements (TG) during the initial stages oxidation of the P92 ferritic steel without and of Al and Al/Si coating by chemical vapour deposition in fluidized bed reactors(CVD-fBR) at 650℃in Ar+20%H_2O for 150 h were *** order to go forward to coatings design the Thermocalc code is used as base for the MSdata. TG-MS experiments were conducted in a closed steam loop in order to obtain information about the oxyhydroxides formation as reaction between coatings and *** those results the role of the different coating element could be established and optimized for the coating *** oxidation mechanism based on the TG-MS results is *** morphology/composition and structure of the oxidized samples were also studied using SEM/EDS and XRD techniques.

关键词：氧化金属腐蚀防护

Multimodal probe for optical coherence tomography epidetection and micron-scale indentation

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journal of Innovative Optical Health Sciences 2017年第6期10卷 64-72页

作者： L.Bartolini f.feroldi j.j.A.Weda M.Slaman j.f.de Boer D.Iannuzzi Department of Physics and Astronomy Vrije Universiteit Amsterdam and LaserLab Amsterdam de Boelelaan 1081 1081HV AmsterdamThe Netherlands

We present a multimodal ferrule-top sensor designed to perform the integrated epidetection of Optical Coberence Tomognphy(OCT)depth-profiles and micron-scale indentation by all-optical *** scarning a sample under the probe,we can obtain structural crosse soction images and identify a region of interest in a nonhomogencous ***,with the same probe and setup,we can immediately target that area with a series of spherical indentation measurements,in which the applied load is known with aμN precision,the indentation depth with sub-/m precision and a maximum contact radius of 100 *** to the visualization of the internal structure of the sample,we can gain a better insi ght into the observed mechanical *** ability to impart a small,confined load,and perfomn OCT A scans at the same time,could lead to an altemative,high transverse resolution,Optical Coherence Elastography(OCE)sensor.

关键词： Optomechanical microindentation optical coherence tomography indentation multimodal sensor,epidetection