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fatigue properties of rolled AZ31B magnesium alloy plate

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Transactions of nonferrous Metals Society of China 2010年第B07期20卷 523-526页

作者： S.MORITA n.OHnO f.TAMAI Y.KAWAKAMI faculty of Science and Engineering Saga University Material and Environment Department Industrial Technology Center of Saga

fatigue strength,crack initiation and propagation behavior of rolled AZ31B magnesium alloy plate were investigated. Axial tension-compression fatigue tests were carried out with cylindrical smooth *** types of specimens were machined with the loading axis parallel(L-specimen)and perpendicular(T-specimen)to rolling *** compressive 0.2%proof stress,tensile strength and tensile elongation were similar for both *** the other hand,monotonic tensile 0.2%proof stress of the L-specimen was slightly higher than that of the ***,monotonic compressive 0.2%proof stresses were lower than tensile ones for both *** fatigue strengths of 107cycles of the L-and T-specimens were 95 and 85 MPa,respectively. Compared with the monotonic compressive 0.2%proof stresses,the fatigue strengths were higher for both *** other words, the fatigue crack did not initiate and propagate even though deformation twins were formed in compressive stress under the cyclic tension-compression *** fatigue crack initiated at early stage of the fatigue life in low cycle regime regardless of specimen *** crack growth rate of the L-specimen was slightly lower than of the ***,the fatigue lives of the L-specimen were longer than those of the T-specimen in low cycle regime.

关键词： magnesium alloy compressive proof stress fatigue strength crack initiation crack propagation

Green ionic metal-organic frameworks as nanocatalysts for CO_(2)fixation

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nano Research 2025年第1期18卷 260-269页

作者： nuria Martín Miguel Maireles-Porcar Julián Sánchez Velandia Belén Altava francisco G.Cirujano Eduardo García-Verdugo Departamento de Química Inorgánica y Orgánica Universidad Jaume IAv.Sos Baynats/nCastellóde la PlanaCastellón 12071Spain

Co,ni,and Zn iso-reticular coordination polymers of 2,5-dihydroxyterphthalic acid(H_(2)dot)can be rapidly obtained under room temperature and aqueous conditions using either sodium or ammonium hydroxide as the bases to deprotonate the *** use of metal bromides and tetrabutylammonium hydroxide(TBAOH)as the base allows the green synthesis of ionic metal-organic frameworks(MOfs),characterized by X-ray diffraction(XRD),fourier transform infrared(fTIR),scanning electron microscopy(SEM),thermo gravimetric analysis(TGA),H-nuclear magnetic resonance(nMR),elemental analysis,and X-ray photoelectron spectroscopy(XPS),and employed in the pressure,solvent,and additive-free CO_(2)fixation to epoxides by its cycloaddition to epichlorohydrin,exhibiting a cooperative behavior between the MOf and the ionic liquid formed within the framework,achieving TOns of the confined tetrabutylammonium bromide(TBABr)up to 700.

关键词： metal-organic frameworks(MOfs) ionic liquids heterogeneous catalysis CO_(2)conversion

A computational study of the role of particle size standard deviation on the collision frequency in differential settling

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International Journal of Sediment Research 2013年第1期28卷 34-45页

作者： C.HEILIGER n.B.KAYE f.Y.TESTIK Civil Engineering Clemson UniversityClemsonSC29634USA

The results of a simple computational model for differential settling are presented illustrating the significant role that particle size distribution plays in collision frequency and sedimentation rate of particles in a quiescent environment. The model tracks a large number of particles（order 10;） with log-normally distributed diameters,as they settle at their Stokes settling *** collisions are detected and result in larger particles that fall more rapidly.A number of simplifying assumptions are made in the model in order to avoid empirical correlations for phenomena such as collision efficiency and particle *** simplifying assumptions were needed to isolate and quantify the role of the particle size *** concentration profiles indicate that,even in the absence of collisions, the standard deviation（σ;） of the particle size strongly influences the bulk mass settling rate as,for largerσ;, more mass is concentrated in larger,faster falling *** collision frequency is also a strong function ofσ;. for a given mass concentration the collision frequency first increases linearly with increasingσ;as greater variation in particle size leads to greater variation in particle velocity,and shorter times for particles to catch each *** largerσ;more mass is concentrated in larger particles,so,for a given mass concentration,there are fewer particles per unit volume,increasing the mean distance between the particles and reducing the collision *** implications of these results for sedimentation measurement using optical attenuation techniques are discussed.

关键词： Settling Sediment size distribution Sediment collision frequency Coefficient of variation

Exploring nationally and regionally defined models for large area population mapping

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International Journal of Digital Earth 2015年第12期8卷 989-1006页

作者： A.E.Gaughan f.R.Stevens C.Linard n.n.Patel A.J.Tatem Department of Geography and Geosciences University of LouisvilleLouisvilleKYUSA Biological Control and Spatial Ecology UniversitéLibre de BruxellesBrusselsBelgium Department of Geography and Geoinformation Science George Mason UniversityFairfaxVAUSA Department of Geography and Environment University of SouthamptonSouthamptonUK fogarty International Center National Institutes of HealthBethesdaMDUSA flowminder foundation StockholmSweden

Interactions between humans,diseases,and the environment take place across a range of temporal and spatial scales,making accurate,contemporary data on human population distributions critical for a variety of *** for disaggregating census data to finer-scale,gridded population density estimates continue to be refined as computational power increases and more detailed census,input,and validation datasets become ***,the availability of spatially detailed census data still varies widely by *** this study,we develop quantitative guidelines for choosing regionally-parameterized census count disaggregation models over country-specific *** examine underlying methodological considerations for improving gridded population datasets for countries with coarser scale census data by investigating regional versus country-specific models used to estimate density surfaces for redistributing census *** is given to the spatial resolution of input census data using examples from East Africa and Southeast *** suggest that for many countries more accurate population maps can be produced by using regionally-parameterized models where more spatially refined data exists than that which is available for the focal *** study highlights the advancement of statistical toolsets and considerations for underlying data used in generating widely used gridded population data.

关键词： human population modeling random forest regression dasymetric mapping gridded population datasets

Mobility of Arsenic and Heavy Metals in a Sandy-Loam Textured and Carbonated Soil

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Pedosphere 2009年第2期19卷 166-175页

作者： I. GARC íA M. DIEZ f. MART ín M. SIMón C. DORROnSORO Departamento Edafologia y Quimica Agricola CITE IIB Carretera Sacramento s/n 04120 University of Almeria (Spain) Departamento Edafologia y Quimica Agricola Campus Fuentenueva s/n 18002 University of Granada (Spain)

The continued effect of the pyrite-tailing oxidation on the mobility of arsenic, lead, zinc, cadmium, and copper was studied in a carbonated soil under natural conditions, with the experimental plot preserved with a layer of tailing covering the soil during three years. The experimental area is located in Southern Spain and was affected by a pyrite-mine spill. The climate in the area is typically Mediterranean, which determines the rate of soil alteration and element mobility. The intense alteration processes that occurred in the soil during three years caused important changes in its morphology and a strong degradation of the main soil properties. In this period, lead concentrated in the first 5 mm of the soil, with concentrations higher than 1500 mg kg?1, mainly associated to the neoformation of plumbojarosite. Arsenic was partially leached from the first 5 mm and mainly concentrated between 5–10 mm in the soil, with maximum values of 1239 mg kg-1; the retention of arsenates was related to the neoformation of iron hydroxysulfates (jarosite, schwertmannite) and oxyhydroxides (goethite, ferrihydrite), both with a variable degree of crystallinity. The mobility of Zn, Cd, and Cu was highly affected by pH, producing a stronger leaching in depth; their retention was related to the forms of precipitated aluminium and, in the case of Cu, also to the neoformation of hydroxysulfate.

关键词： arsenic heavy metals oxidation pyrite-tailing soil

Using mixed integer programming and airborne laser scanning to generate forest management units

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Journal of forestry Research 2022年第1期33卷 217-226页

作者： Adrián Pascual Sándor fTóth forest Research Centre School of AgricultureUniversity of LisbonTapada da Ajuda1349-017 LisboaPortugal School of forest Sciences University of Eastern FinlandP.O.Box 11180101 JoensuuFinland School of Environmental and forest Sciences University of WashingtonSeattleWAUSA

Airborne laser scanning(ALS)has been widely applied to estimate tree and forest attributes,but it can also drive the segmentation of forest *** algorithms are the dominant technique in segmentation but spatial optimization using exact methods remains *** study presents a novel approach to segmentation based on mixed integer programming to create forest management units(fMUs).This investigation focuses on using raster information derived from ALS *** mainstream clustering algorithms were compared to the new MIP formula that simultaneously accounts for area and adjacency restrictions,fMUs size and homogeneity in terms of vegetation *** optimal problem solution was found when using less than 150 cells,showing the problem formulation is *** results for MIP were better than for the clustering algorithms;fMUs were more compact based on the intravariation of canopy height and the variability in size was *** MIP model allows the user to strictly control the size of fMUs,which is not possible in heuristic optimization and in the clustering algorithms *** definition of forest management units based on remote sensing data is an important operation and our study pioneers the use of MIP ALS-based optimal segmentation.

关键词： Segmentation Precision forestry Optimization Mathematical programming Airborne laser scanning

GDnf to the rescue:GDnf delivery effects on motor neurons and nerves,and muscle re-innervation after peripheral nerve injuries

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neural Regeneration Research 2022年第4期17卷 748-753页

作者： Alberto f.Cintrón-Colón Gabriel Almeida-Alves Juliana M.VanGyseghem John M.Spitsbergen Biological Sciences Department Western Michigan UniversityKalamazooMIUSA

Peripheral nerve injuries commonly occur due to trauma,like a traffic *** nerves get severed,causing motor neuron death and potential muscle *** current golden standard to treat peripheral nerve lesions,especially lesions with large(≥3 cm)nerve gaps,is the use of a nerve autograft or reimplantation in cases where nerve root avulsions *** not tended early,degeneration of motor neurons and loss of axon regeneration can occur,leading to loss of *** surgical procedures exist,patients often do not fully recover,and quality of life *** nerves have limited regeneration,and it is usually mediated by Schwann cells and neurotrophic factors,like glial cell line-derived neurotrophic factor,as seen in Wallerian *** cell line-derived neurotrophic factor is a neurotrophic factor known to promote motor neuron survival and neurite *** cell line-derived neurotrophic factor is upregulated in different forms of nerve injuries like axotomy,sciatic nerve crush,and compression,thus creating great interest to explore this protein as a potential treatment for peripheral nerve *** glial cell line-derived neurotrophic factor has shown positive effects in regeneration and functional recovery when applied in experimental models of peripheral nerve *** this review,we discuss the mechanism of repair provided by Schwann cells and upregulation of glial cell line-derived neurotrophic factor,the latest findings on the effects of glial cell line-derived neurotrophic factor in different types of peripheral nerve injuries,delivery systems,and complementary treatments(electrical muscle stimulation and exercise).Understanding and overcoming the challenges of proper timing and glial cell line-derived neurotrophic factor delivery is paramount to creating novel treatments to tend to peripheral nerve injuries to improve patients'quality of life.

关键词： electrical muscle stimulation exercise glial cell line-derived neurotrophic factor glial cell line-derived neurotrophic factor delivery motor neuron nerve gap neurotrophic factor peripheral nerve injury Schwann cells skeletal muscle atrophy

Differential response of injured and healthy retinas to syngeneic and allogeneic transplantation of a clonal cell line of immortalized olfactory ensheathing glia:a double-edged sword

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neural Regeneration Research 2025年第8期20卷 2395-2407页

作者： María norte-Muñoz María Portela-Lomba Paloma Sobrado-Calvo Diana Simón Johnny Di Pierdomenico Alejandro Gallego-Ortega Mar Pérez JoséMCabrera-Maqueda Javier Sierra Manuel Vidal-Sanz María Teresa Moreno-flores Marta Agudo-Barriuso Grupo de Investigación Oftalmología Experimental Departamento de OftalmologíaOptometríaOtorrinolaringología y Anatomía PatológicaFacultad de MedicinaUniversidad de MurciaInstituto Murciano de Investigación Biosanitaria(IMIB)Campus de Ciencias de la SaludMurciaSpain Experimental Sciences faculty Universidad Francisco de VitoriaPozuelo de AlarcónMadridSpain Anatomy Histology and Neuroscience DepartmentMedicine FacultyUniversidad Autónoma de MadridMadridSpain Center of neuroimmunology Service of NeurologyLaboratory of Advanced Imaging in Neuroimmunological DiseasesHospital Clínic of BarcelonaInstitut d’Investigacions Biomèdiques August Pi i Sunyer(IDIBAPS)and Universitat de BarcelonaBarcelonaSpain Medicine faculty Universidad Francisco de VitoriaPozuelo de AlarcónMadridSpain

Olfactory ensheathing glia promote axonal regeneration in the mammalian central nervous system,including retinal ganglion cell axonal growth through the injured optic ***,it is unknown whether olfactory ensheathing glia also have neuroprotective *** ensheathing glia express brain-derived neurotrophic factor,one of the best neuroprotectants for axotomized retinal ganglion ***,we aimed to investigate the neuroprotective capacity of olfactory ensheating glia after optic nerve *** ensheathing glia cells from an established rat immortalized clonal cell line,TEG3,were intravitreally injected in intact and axotomized retinas in syngeneic and allogeneic mode with or without microglial inhibition or immunosuppressive *** and gene expression analyses were *** bulb-derived primary olfactory ensheathing glia and TEG3 express major histocompatibility complex classⅡ*** and syngenically transplanted TEG3 cells survived in the vitreous for up to 21 days,forming an *** axotomized retinas,only the allogeneic TEG3 transplant rescued retinal ganglion cells at 7 days but not at 21 *** these retinas,microglial anatomical activation was higher than after optic nerve crush *** intact retinas,both transplants activated microglial cells and caused retinal ganglion cell death at 21 days,a loss that was higher after allotransplantation,triggered by pyroptosis and partially rescued by microglial inhibition or ***,neuroprotection of axotomized retinal ganglion cells did not improve with these *** different neuroprotective properties,different toxic effects,and different responses to microglial inhibitory treatments of olfactory ensheathing glia in the retina depending on the type of transplant highlight the importance of thorough preclinical studies to explore these variables.

关键词： cell therapy immune recognition major histocompatibility complex class II(MHCII) neuroprotection olfactory ensheathing glia retinal ganglion cells

On POInTWISE R-SUBWEAKLY COMMUTInG MAPS AnD BEST APPROXIMATIOnS

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Analysis in Theory and Applications 2008年第1期24卷 40-49页

作者： f. Akbar n. Sultana University of Sargodha Pakistan

The main purpose of this paper is to prove some common fixed point theorems for pointwise R-subweakly commuting maps on non-starshaped domains in p-normed spaces and locally convex topological vector spaces. As applications, invariant approximation results are established. This work provides extension as well as substantial improvement of several results in the existing literature.

关键词： common fixed point contractive family of functions pointwise R-subweaklycommuting maps invariant approximation