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Science China(Technological Sciences) 2019年第6期62卷 1055-1064页

作者： MARTINEZ-MORALES Jose quej-cosgaya hector LAGUNAS-JIMENEZ Jose PALACIOS-HERNANDEZ Elvia MORALES-SALDANA Jorge Faculty of Engineering Autonomous University of Campeche Campeche 24039 Mexico Faculty of Sciences Autonomous University of San Luis Potosi San Luis Potosi 78290 Mexico Faculty of Engineering Autonomous University of San Luis Potosi San Luis Potosi 78290 Mexico

A multilayer perceptron(MLP) artificial neural network(ANN) model has been optimized by the multi-objective ant colony optimization(MOACO) algorithm, which uses three objective functions. A sensitivity analysis to choose MOACO parameter values is carried out by calculating hypervolume metric, and the proposed approach adopts the Vlsekriterijumska Optimizacija I Kompromisno Resenje(VIKOR) decision method to choose final compromised solution on the Pareto front obtained from MOACO. As a result, we used the MLP-MOACO developed model to estimate the value of engine emissions of NOxin a four stroke, spark ignition(SI) gasoline engine and observed acceptable correlation coefficient(R^2) of 0.99978.

关键词： ant colony optimization multilayer perceptron artificial neural networks hypervolume engine emissions

Corrosion testing of X52 and X80 steels immersed in stimulated emulsions using a real petroleum sample

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Petroleum Research 2024年第2期9卷 304-316页

作者： L.M.quej-Ake J.L.Alamilla A.Contreras Instituto Mexicano del Petróleo Eje Central Lázaro CárdenasNorte 152San Bartolo AtepehuacanGustavo A.MaderoCiudad de MéxicoC.P.07730México

The aim of this study is to evaluate the internal corrosion process on X52 and X80 steels/real petroleum interfaces containing condensed hydrocarbon plus oilfield-produced water,which were subjected to stimulated emulsions using 50/50 vol ratio mixtures at 45℃,different hydrodynamic conditions,1 h,and 24 h.A washing process by using deionized water was proposed to simulate and identify the corrosiveness of the hydrocarbon phase after 24 h of exposure *** characterization by electrochemical impedance spectroscopy and the monitoring of the polarization curves indicated that X80 steel/oilfield-produced water interfaces were more susceptible to corrosion than X52 steel exposed to oilfield-produced *** combined speed rotation of 600 rpm using a magnetic stirrer+600 rpm using a rotating disk electrode decreased the corrosion rate on X52 *** stimulated emulsions made of hydrocarbon+oilfield-produced water and hydrocarbon+deionized water at 24 h increased the corrosion rate on X80 steel(0.34 mm/year and 0.43 mm/year,respectively),promoting the formation of erosion and pitting *** types of corrosion depended mainly on the physicochemical properties of the hydrocarbon,oilfield-produced water,exposure times,and hydrodynamic systems in which the hydrocarbon was studied.

关键词： Corrosion Emulsions X52 steel X80 steel

Locomotor recovery after spinal cord injury:intimate dependence between axonal regeneration and re-connection

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Neural Regeneration Research 2022年第3期17卷 553-554页

作者： hector Ramiro Quintá Consejo Nacional de Investigaciones Científicas y Técnicas CONICET Laboratorio de Medicina Experimental“Dr.Jorge E.Toblli” Hospital AlemánBuenos AiresArgentina

Traumatic spinal cord injuries(SCI) are characterized by damage in the integrity of the spinal cord,which results in either temporary or permanent alterations in the locomotor,sensory and/or autonomic functions(Yezierski,2009).The traumatic event leads to impairments in voluntary control of movement below the injury by affecting the connection between the brain and the neurons localized in the spinal cord.

关键词： injuries alterations damage

Beam design for voice coil motors used for energy harvesting purpose with low frequency vibrations:A finite element analysis

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International Journal of Modeling, Simulation, and Scientific Computing 2016年第3期7卷 1-17页

作者： hector A.Tinoco Department of Mechanics and Production Universidad Autonoma de Manizales(UAM)Grupo de Diseno Mecanico y Desarrollo Industrial Antigua Estaci´on del Ferrocarril Edificio Sacatin C.P.170001 Manizales-Caldas Colombia

In this study,a numerical approach is established to design a beam coupled to a Voice Coil Motor(VCM)with the aim to maximize the displacement in the inductive transducer.A finite element model is developed to simulate a VCM with different beams applying a harmonic *** VCM is extracted from a recycled hard disk drive(HDD)and a parametric modal analysis is performed to identify the material parameters of the HDD and the *** parameters are obtained comparing the real vibration modes and natural frequencies(VCM-beam)with those determined from the finite element model.A numerical-experimental case study is carried out to demonstrate that if a beam is designed for a specific low frequency vibration between 0 and 10 Hz,the displacements are maximized in the *** this purpose,real acceleration measurements taken from three individuals are used to provide the vibration signals in the numerical model.A beam is designed for one of the individuals using the natural frequency values determined from the measured *** show that the displacements are maximized in the model which coincides with the natural frequency of the chosen *** main purpose of this research is to establish a design tool for energy harvesting purposes with VCM based on low frequency vibration sources as for example gait motions.

关键词： Hard disk drive HDD energy harvesting finite element analysis Wiimote voice coil motor VCM modal analysis

Inference for a truncated positive normal distribution

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Applied Mathematics(A Journal of Chinese Universities) 2018年第2期33卷 163-176页

作者： hector J.Gomez Neveka M.Olmos hector Varela Heleno Bolfarine Departamento de Ciencias Matematicas y Ffsicas Facultad de IngenierlaUniversidad Catolica de TemucoTemucoChile Departamento de Matematicas Facultad de Ciencias BasicasUniversidad de AntofagastaAntofagastaChile Departamento de Estatfstica IMEUniversidade de Sao PauloSao PauloBrazil

The main object of this paper is to study an extension of the half normal distribution defined by adding a positive truncation to it. The new model is more flexible than the half-normal distribution and contains the half normal distribution as a special case. Properties of this distribution, such as moments, hazard function and entropy are studied and parameters estimation is dealt with by using inoinents and inaxiinuin likelihood. A real data application indicates good fit performance of the new model when compared to other competitors in litera- tures.

关键词： half-normal distribution maximum likelihood truncation

Molecular aspects of mammalian fertilization

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Asian Journal of Andrology 2001年第4期3卷 243-249页

作者： hector Serrano Dolores Garcia-Suarez Dept. Health Sciences Dept. Biology Universidad Autonoma Metropoliana-Iztapalapa Ave. Michoacan and Purisima Mexico City DF 09340 Mexico

Mammalian fertilization is a highly regulated process, much of which are not clearly understood. Here we presentsome information in order to elaborate a working hypothesis for this process, beginning with the sperm modifications inthe epidydimis up to sperm and egg plasmalemma interaction and fusion. We also discuss the still poorly understood ca-pacitation process, the phenomenon of sperm chemo-attraction that brings the capacitated sperm to interact with theoocyte vestments and certain aspects of the acrosome reaction. (Asian J Androl 2001 Dec; 3 : 243 - 249)

关键词： fertilization sperm maturation sperm capacitation sperm-ovum interactions membrane fusion

The implementation and data analysis of an interferometer for intense short pulse laser experiments

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High Power Laser Science and Engineering 2016年第3期4卷 60-66页

作者： Jaebum Park hector A.Baldis Hui Chen Lawrence Livermore National Laboratory University of California

We present an interferometry setup and the detailed fringe analysis method for intense short pulse(SP) laser *** interferometry scheme was refined through multiple campaigns to investigate the effects of pre-plasmas on energetic electrons at the Jupiter Laser Facility at Lawrence Livermore National Laboratory. The interferometer used a frequency doubled(λ=0.527 μm) 0.5 ps long optical probe beam to measure the pre-plasma density, an invaluable parameter to better understand how varying pre-plasma conditions affect the characteristics of the energetic electrons. The hardware of the diagnostic, data analysis and example data are presented. The diagnostic setup and the analysis procedure can be employed for any other SP laser experiments and interferograms, respectively.

关键词： Mach-Zehnder interferometer optical interferometry picosecond probe plasma density short pulse laser

Radicals and Kothe’s Conjecture for Skew PBW Extensions

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Communications in Mathematics and Statistics 2021年第2期9卷 119-138页

作者： Armando Reyes hector Suarez Departamento de Matematicas Universidad Nacional de ColombiaSede BogotaColombia Escuela de Matemáticas y Estadística Universidad Pedagogica y Tecnológica de ColombiaSede TunjaColombia

The aim of this paper is to investigate different radicals(Wedderburn radical,lower nil radical,Levitzky radical,upper nil radical,the set of all nilpotent elements,the sum of all nil left ideals)of the noncommutative rings known as skew Poincare–Birkhoff–Witt *** characterize minimal prime ideals of these rings and prove that the Kothe’s conjecture holds for these ***,we establish the transfer of several ring-theoretical properties(reduced,symmetric,reversible,2-primal)from the coefficients ring of a skew PBW extension to the extension itself.

关键词： Armendariz rings Kothe’s conjecture Skew PBW extensions

A study of process-induced grain structures during steady state and non-steady state electron-beam welding of a titanium alloy

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Journal of Materials Science & Technology 2022年第18期113卷 117-127页

作者： Yu Lu Richard Turner Jeffery Brooks hector Basoalto School of Metallurgy and Materials University of BirminghamBirminghamB152TTUnited Kingdom Department of Materials Science and Engineering The University of SheffieldMappin StreetSheffieldS13JDUnited Kingdom

A detailed microstructural characterisation of the emerging weld-line grain structure,for bead-upon-plate welds in Ti-6Al-4V(Ti64)of differing plate thickness,was *** microstructure studied was formed during both steady state and non-steady state sections within the weld path,with the non-steady state portion being taken from the end of the plate as the weld bead and heat source overhang the edge of the *** allows for the effects of welding process conditions on the microstructural evolution to be *** weld pool geometry and 3D tomography of the weld-induced defects have been *** characterisation of microstructure and texture for different welding parameters and for steady and non-steady states have been used to identify physical parameters for the microstructure predictions that are difficult to obtain *** different states significantly affect the weld crown shape and formation,weld toe,weld bead depth and ***,the heat affected zone(HAZ)re-mains *** the microstructural evolution,both the steady and non-steady states have similar microstructure and *** defects were observed in the steady state section of welds,but sub-surface spherical pores have been observed in the non-steady state section of a *** element modelling to simulate the thermal-metallurgical-mechanical fields within the steady and non-steady state sections of the welds was considered,and the cooling rates predicted within steady state and non-steady sections were interrogated to improve the theoretical understanding of the microstructure and defect formation differences in these Ti64 EB weld regions.

关键词： Electron-beam fusion welding Processing Microstructure Ti-6Al-4V

Tales of the Tail and Sperm Head Aches --Changing concepts on the prognostic significance of sperm pathologies affecting the head, neck and tail

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Asian Journal of Andrology 2012年第1期14卷 14-23,174页

作者： hector E Chemes Cristian Alvarez Sedo Laboratory of Testicular Physiology and Pathology Center for Research in Endocrinology National Research Council （CONICET） Endocrinology Division Buenos Aires Children＇s Hospital Gallo 1330 C1425SEFD Buenos Aires Argentina Centro de Estudios en Ginecologia y Reproduccion （CEGyR） C1425SEFD Buenos Aires Argentina

This article presents an update on the variable prognostic significance of different sperm pathologies in patients with severe male factor infertility due to morphology and motility disorders. Severe asthenozoospermia is one of the leading causes of male infertility as spermatozoa cannot reach the oocyte and/or penetrate normally. Identifying structural causes of sperm immotility was of great concern before the advent of intracytoplasmic sperm injection （ICSI）, because immotility was the limiting factor in the treatment of these patients. In these cases, in vitro methods are used to identify live spermatozoa or stimulate sperm motility to avoid selection of non-viable cells. With these advances, fertilization and pregnancy results have improved dramatically. The identification of genetic phenotypes in asthenozoospermia is important to adequately inform patients of treatment outcomes and risks. The one sperm characteristic that seriously affects fertility prognosis is teratozoospermia, primarily sperm head and neck anomalies. Defects of chromatin condensation and acrosomal hypoplasia are the two most common abnormalities in severe teratozoospermia. The introduction of microscopic methods to select spermatozoa and the development of new ones to evaluate sperm quality before ICSI will assure that ultrastructural identification ofsperm pathologies will not only be of academic interest, but will also be an essential tool to inform treatment choice. Herein, we review the differential roles played by sperm components in normal fertilization and early embryo development and explore how assisted reproductive technologies have modified our concepts on the prognostic significance of sperm pathologies affecting the head, neck, mid-piece and tail.

关键词： acrosomal hypoplasia chromatin anomalies fertility prognosis intracytoplasmic sperm injection intracytoplasmic injection of morphologically selected spermatozoa sperm neck defects sperm pathologies tail abnormalities teratozoospermia