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Generalized Height-Diameter Models for Pinus montezumae Lamb. and Pinus pseudostrobus Lindl. Plantations in Michoacan, Mexico

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Open Journal of Forestry 2024年第3期14卷 214-232页

作者： Jonathan Hernández-Ramos Valentín josé reyes-Hernández Héctor Manuel De los Santos-Posadas Aurelio Manuel Fierros-González Enrique Buendía-Rodríguez Gerónimo Quiñonez-Barraza Instituto Nacional de Investigaciones Forestales Agrcolas y Pecuarias (INIFAP)-Campo Experimental Bajo Celaya Guanajuato Mxico Colegio de Postgraduados (COLPOS) Campus Montecillo Mxico INIFAP Campo Experimental Valle de Mxico Texcoco Mxico INIFAP Campo Experimental Valle del Guardiana Durango Mxico

Tree height (H) in a natural stand or forest plantation is a fundamental variable in management, and the use of mathematical expressions that estimate H as a function of diameter at breast height (d) or variables at the stand level is a valuable support tool in forest inventories. The objective was to fit and propose a generalized H-d model for Pinus montezumae and Pinus pseudostrobus established in forest plantations of Nuevo San Juan Parangaricutiro, Michoacan, Mexico. Using nonlinear least squares (NLS), 10 generalized H-d models were fitted to 883 and 1226 pairs of H-d data from Pinus montezumae and Pinus pseudostrobus, respectively. The best model was refitted with the maximum likelihood mixed effects model (MEM) approach by including the site as a classification variable and a known variance structure. The Wang and Tang equation was selected as the best model with NLS;the MEM with an additive effect on two of its parameters and an exponential variance function improved the fit statistics for Pinus montezumae and Pinus pseudostrobus, respectively. The model validation showed equality of means among the estimates for both species and an independent subsample. The calibration of the MEM at the plot level was efficient and might increase the applicability of these results. The inclusion of dominant height in the MEM approach helped to reduce bias in the estimates and also to better explain the variability among plots.

关键词： Random Covariate Random Effects Variance Structure Forest Inventories Forest Management Mixed Models

Dendritic Growth, Eutectic Features and Their Effects on Hardness of a Ternary Sn–Zn–Cu Solder Alloy

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Acta Metallurgica Sinica(English Letters) 2017年第6期30卷 528-540页

作者： Bismarck Luiz Silva Rodrigo Valenzuela reyes Amauri Garcia joséEduardo Spinelli Department of Materials Engineering Federal University of Rio Grande do Norte-UFRNNatalRN 59078-970Brazil Department of Materials Engineering Federal University of Sao Carlos-UFSCarSao CarlosSP 13565-905Brazil Department of Manufacturing and Materials Engineering University of CampinasUNICAMPCampinasSP 13083-860Brazil

The present investigation is based on the results of a directionally solidified （DS） Sn-9 wt%Zn-2 wt%Cu alloy, including primary/secondary/tertiary dendrite arm spacings of the Sn-rich matrix, the morphologies of the eutectic mixture and the corresponding interphase spacing, the nature and proportion of the Cu-Zn intermetallic compound （IMC）. The main purpose is to establish interrelations of these microstructure features with experimental solidification thermal parameters, such as cooling rates and growth rates （v）, macrosegregation and hardness. Such interrelations are interesting for both industry and academy since they represent a tool permitting the preprogramming of final properties based on the design of the microstructure. In the case of Sn-Zn-Cu alloys, hardly anything is known about the combined effects of the length scale of the microstructure and fraction and distribution of the primary IMC on hardness. The alloy microstructure is composed of a β-Sn dendritic region, surrounded by a eutectic mixture of α-Zn and β-Sn phases and the γ-Cu5Zn8 IMC. The eutectic interphase spacing varies in the range 1.2-3.6 μm, with the α-Zn phase having a globular morphology for ν 〉 0.5 mm/s and a needle-like morphology for ν 〈 0.3 mm/s. A modified Hall-Petch-type experimental expression relating hardness to the interphase spacing is proposed.

关键词： Sn-Zn-Cu solder alloy Solidification Microstructure Eutectic morphology Hardness

Characterization of Cd1-xZnxTe（0≤x≤1） Nanolayers Grown by Atomic Layer Deposition on GaSb and GaAs（001） Oriented Substrates

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Journal of Electronic Science and Technology 2019年第2期17卷 97-108页

作者： Joel Díaz-reyes Roberto Saúl Castillo-Ojeda josé Eladio Flores-Mena Center for Research in Applied Biotechnology Instituto Politécnico Nacional Tepetitla 90700 Mexico Universidad Politécnica de Pachuca Pachuca 43830 Mexico Faculty of Sciences of the Electronics Autonomous University of Puebla Puebla 72570 Mexico

ZnTe, CdTe, and the ternary alloy CdZnTe are important semiconductor materials used widely for the detection of an important range of electromagnetic radiation as gamma ray and X-ray. Although, recently these materials have acquired renewed importance due to the new explored nanolayer properties of modern devices. In addition, as shown in this work they can be grown using uncomplicated synthesis techniques based on the deposition in vapour phase of the elemental precursors. This work presents the results obtained from the deposition of nanolayers of these materials using the precursor vapour on GaAs and GaSb (001) substrates. This growth technique, extensively known as atomic layer deposition (ALD), allows the layers growth with nanometric dimension. The main results presented in this work are the used growth parameters and the results of the structural characterization of the layers by the means of Raman spectroscopy measurements. Raman scattering shows the peak corresponding to longitudinal optical (LO)-ZnTe, which is weak and slightly redshift in comparison with that reported for the ZnTe bulk at 210 cm^-1. For the case of the CdTe nanolayer, Raman spectra presented the LO-CdTe peak, which is indicative of the successful growth of the layer. Its weak and slightly redshift in comparison with that reported for the CdTe bulk can be related with the nanometric characteristic of this layer. The performed high-resolution X-ray diffraction (HR-XRD) measurement allows to study some important characteristics such as the crystallinity of the grown layer. In addition, the HR-XRD measurement suggests that the crystalline quality has dependence on the growth temperature.

关键词： Ⅲ-Ⅴ substrates atomic layer deposition(ALD) defect generation mechanism ternary alloy Cd1-xZnxTe Zn and Cd mixture

Integral Representation Formulas Related to the Lamé–Navier System

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Acta Mathematica Sinica,English Series 2020年第12期36卷 1341-1356页

作者： Ricardo ABREU-BLAYA Juan BORY-reyes Marcos Antonio-HERRERA-PELáEZ josé María SIGARRETA-ALMIRA Facultad de Matemáticas Universidad Autónoma de GuerreroGuerreroMéxico Instituto Politécnico Nacional SEPI-ESIME-ZAC CD-MXMéxico

The paper provides integral representations for solutions to a certain first order partial differential equation natural arising in the factorization of the Lamé–Navier system with the help of Clifford analysis *** representations look like in spirit to the Borel–Pompeiu and Cauchy integral formulas both in three and higher dimensional setting.

关键词： Lamésystem Clifford analysis Dirac operator

The ρ-variation of the Hermitian Riesz Transform

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Acta Mathematica Sinica,English Series 2010年第10期26卷 1827-1838页

作者： Raquel CRESCIMBENI Francisco Javier MARTíN-reyes Alberto DE LA TORRE josé L.TORREA Departamento de Matemática Universidad Nacional del Comahue Facultad de Economía y Administración Departamento de Análisis Matemático Facultad de Ciencias Universidad de Málaga Facultad de Ciencias Universidad Autónoma de Madrid ICMAT-CSIC-UAM-UCM-UC3M

In this paper we prove the behaviour in weighted Lp spaces of the oscillation and variation of the Hilbert transform and the Riesz transform associated with the Hermite operator of dimension 1. We prove that this operator maps LP（R, w（x）dx） into itself when w is a weight in the Ap class for 1 〈 p 〈 ∞. For p = 1 we get weak type for the A1 class. Weighted estimated are also obtained in the extreme case p = ∞.

关键词： Oscillation-p-variation-singular integral-Hermite operator

XRD Characterization of Crystallinity of Human Tooth Enamel under Influence of Mechanical Grinding

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Materials Sciences and Applications 2015年第6期6卷 464-472页

作者： jose reyes-gasga Olga Koudriavtseva Raul Herrera-Becerra Arturo Escobosa Instituto de Física UNAM Circuito de la Investigación s/n Ciudad Universitaria México D.F. México Dep. Ingeniería Eléctrica—SEES CINVESTAV—IPN México D.F. México

Crystallinity refers to the degree of structural order in a solid and has a big influence on hardness, density, transparency and diffusion. Even within materials that are crystalline completely, the degree of structural perfection can vary, reflecting size and elastic strain of many independent crystalline regions (grains or crystallites) of which these materials are composed. In this work it was attempted to reduce the crystallinity of human enamel using a technique of mechanical grinding (MG) with an ultra-compact FRITSCH Mini-Mill PULVERISETTE 23 machine. Variation in the crystallinity through the MG was monitored by X-ray diffraction (XRD) by broadening of the diffraction peak and examined using the Williamson-Hall plot method. Crystallites in human enamel are regularly arranged and oriented (in the [001] direction) perpendicularly to the interface of enameldentin junction. The results showed an anisotropic feature in crystallinity. Reduction of the crystallinity along the a-axis is due to the crystal strain rather than to the refinement of crystal, and vice versa along the c-axis. After 230 h of the MG, the length of crystallites decreased from 100 nm to 30 nm and width from 40 nm to 37 nm approximately.

关键词： Human Tooth Enamel Crystal Structure Mechanical Grinding X-Ray Diffraction Crystallites

Avian-power line interactions in the Gobi Desert of Mongolia:are mitigation actions effective?

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Avian Research 2021年第3期12卷 382-390页

作者： Adrian Orihuela-Torres Juan MPérez-García Zebensui Morales-reyes Lara Naves-Alegre joséASánchez-Zapata Esther Sebastián-González Área de Ecología Departamento de Biología AplicadaUniversidad Miguel Hernández de ElcheAvda.Universidad s/n03202 ElcheAlicanteSpain Departamento de Ecología Universidad de AlicanteCtra.San Vicente del Raspeig s/n03690 San Vicente del RaspeigAlicanteSpain

Background:Electrocution and collisions on power lines are among the leading causes of non-natural mortality for *** lines are exponentially increasing,particularly in developing countries,but mitigation strategies to prevent bird mortality are *** combines a recently increased power line network,an abundant raptor population,a dangerous crossarm configuration and a habitat with no natural perches,producing many bird-power line *** aim is to assess the bird mortality caused by power lines in the Gobi Desert of Mongolia,to determine the factors increasing the risk of bird electrocution,and to evaluate the effectiveness of used retrofitting ***:In July 2019 we covered 132.9 km of 15 kV power lines checking 1092 *** also conducted bird tran-sects to record raptor and corvid richness and abundance,to assess species vulnerability to ***:We recorded 76 electrocuted birds of 7 *** rate was 6.96 birds/100 *** most affected species were Common Raven(Corvus corax)and Upland Buzzard(Buteo hemilasius),highlighting the electro-cution of 5 endangered Saker Falcons(Falco cherrug).By contrast,we only recorded 8 individuals of 5 species collid-ing with wires,the most affected being Pallas’s Sandgrouse(Syrrhaptes paradoxus).About 76.1%of sampled poles had some mitigation *** these,96.6%were brush perch deflectors and 3.4%rotating-mirrors perch *** found differences in electrocution rates among crossarm configurations,with the strain insulator with one jumper being the most ***,we found no correlation between bird abundance and electrocution rates,suggesting that some species are more sensitive to *** no differences in total bird electrocu-tion rates were detected between poles with and without perch deterrents,when bird size is considered,deterrents reduced the mortality rate of small birds,while they were ineffective for medium-sized

关键词： Collision Crossarm configuration Electrocution Electric infrastructures Perch deterrent Power line network Raptor

Skin problems in children under five years old at a rural hospital in Southern Ethiopia

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Asian Pacific Journal of Tropical Biomedicine 2016年第7期6卷 625-629页

作者： josé Manuel Ramos Paula Moles-Poveda Dalu Tessema Mubarack Kedir Gamadi Safayo Abraham Tesfasmariam Francisco reyes Isabel Belinchon Department of Paediatrics and General Medicine Gambo General Rural Hospital Department of Internal Medicine Hospital General Universitario de Alicante Department of Clinical Medicine Universidad Miguel Hernandez de Elche Department of Dermatology Hospital Arnau de Vilanova Department of Dermatology Hospital General Universitario de Alicante

Objective: To examine the prevalence of cutaneous disorders in children under 5 years old who attended a rural hospital in Southern ***: A prospective cross-sectional study was conducted from January 26 to February 20, 2015 in children under 5 years old who attended Gambo Rural Hospital in West Arsi of the Oromia Region, ***: A total of 324 children were included(59.6% male) whose median age was 16.4months. In total, 147 children [45.4%; 95% confidence interval(CI): 40.0%–50.8%]under 5 years had a skin problem, of which 101(68.7%) consulted for that reason. The other 46(31.3%) consulted for a general health problem and the dermatological condition was a secondary finding during the physical exploration. In 93 children(28.7%; 95% CI:20%–33.8%), it was the main disease, and in 54 children(16.5%; 95% CI: 13.0%–21.1%)it was concomitant with other diseases. The most common dermatological disease was scabies(n = 44, 13.6%; 95% CI: 10.3%–17.7%). Impetigo was diagnosed in 32 children(9.9%; 95% CI: 7.1%–13.3%), of which 23(71.9%) had complicated impetigo. Nineteen children(5.9%; 95% CI: 3.8%–9.0%) had eczema, 10(3.1%) had eczema associated to other conditions. The following most frequent skin problems were tinea(n = 9; 2.8%),infected wound and ulcer(n = 7; 2.2%), and burns(n = 6; 1.9%).Conclusions: Skin problems, mainly scabies, impetigo, and eczema were common in young children attended at a rural hospital in Southern Ethiopia. Children under 5 years should be examined thoroughly to rule out skin diseases, especially scabies.

关键词： Children Under five years Skin problem Scabies Impetigo

Solar Driven Wind Speed Monitoring System Using Wireless or Wired Sensors

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Energy and Power Engineering 2014年第9期6卷 213-221页

作者： Federico Hahn Mauricio Pablo josé reyes Department of Irrigation Universidad Autonoma Chapingo Texcoco México

Instrumented towers are being constructed to characterize vertical wind profiles in order to improve the understanding and characterization of a desired environment up to 100 m. The site being measured is at a height of 2500 m over sea level, in one side of Sierra Madre Oriental, which crosses Mexico from North to South. As the site has no energy, it was powered by a photovoltaic system. Power consumption of two sets of sensors fixed at the tower was evaluated. The first sensor set consisted of a pulsed anemometer and a RH sensor having a 0 - 10 V output;these sensors used cables for transmitting the output signals. Three cup anemometers fixed at 25, 35 and 45 m high measured wind speed. Wireless sensors in the second set, requires of a power consumption and battery life study. Solar cells energized the sensors, becoming the installation and operation easier. The datalogger that acquired the RH and T measurements encountered an 11% voltage loss throughout the cable;cup anemometer measurements did not show variations due to its pulsed signals. Wireless sensors drew less energy from the PV system, resulting in battery overcharge. A dump regulator turned-on a 200 W lamp during the night when the battery voltage reached 14 V;the lamp was turned-off when the battery voltage felt beneath 11.5 V. Considering the high wind available, wireless sensors batteries were charged by small wind turbines combined with 5 W solar panels.

关键词： Wind Tower Wireless Anemometers Battery Regulator