检索结果-南通市图书馆

Output feedback adaptive super twisting sliding mode control for quadrotor UAVs

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

control Theory and Technology 2024年第1期22卷 92-105页

作者： Oscar Salas-Peña Jesus DeLeón-Morales Susana V.gutiérrez-martínez École centrale de Nantes-LS2N UMR 6004 CNRS44300NantesFrance Facultad de Ingeniería Mecánica y Eléctrica Universidad Autónoma de Nuevo León66451San Nicolás de Los GarzaMexico

In this paper, a sliding mode control with adaptive gain combined with a high-order sliding mode observer to solve the tracking problem for a quadrotor UAV is addressed, in presence of bounded external disturbances and parametric uncertainties. The high order sliding mode observer is designed for estimating the linear and angular speed in order to implement the proposed scheme. Furthermore, a Lyapunov function is introduced to design the controller with the adaptation law, whereas an analysis of finite time convergence towards to zero is provided, where sufficient conditions are obtained. Regarding previous works from literature, one important advantage of proposed strategy is that the gains of control are parameterized in terms of only one adaptive parameter, which reduces the control effort by avoiding gain overestimation. Numerical simulations for tracking control of the quadrotor are given to show the performance of proposed adaptive control–observer scheme.

关键词： Adaptive super twisting controller High-order sliding modes observer UAV

Single atom cu-N-c catalysts for the electro-reduction of cO_(2) to cO assessed by rotating ring-disc electrode

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy chemistry 2024年第1期88卷 169-182,I0004页

作者： S.Pérez-Rodríguez M.gutiérrez-Roa c.Giménez-Rubio D.Ríos-ruiz P.Arévalo-cid M.V.martínez-Huerta A.Zitolo M.J.Lázaro D.Sebastián Instituto de carboquímica(cSIc) Miguel Luesma Castán 450018 ZaragozaSpain Instituto de catálisis y Petroleoquímica(cSIc) Marie Curie 228049 MadridSpain Synchrotron SOLEIL L’Orme des MerisiersDépartementale 12891190France

The electrochemical cO_(2) reduction reaction(cO_(2)RR) to controllable chemicals is considered as a promising pathway to store intermittent renewable energy. Herein, a set of catalysts based on copper-nitrogendoped carbon xerogel(cu-N-c) are successfully developed varying the copper amount and the nature of the copper precursor, for the efficient cO_(2)RR. The electrocatalytic performance of cu-N-c materials is assessed by a rotating ring-disc electrode(RRDE), technique still rarely explored for cO_(2)RR. For comparison, products are also characterized by online gas chromatography in a H-cell. The as-synthesized cu-Nc catalysts are found to be active and highly cO selective at low overpotentials(from -0.6 to -0.8 V ***) in 0.1 M KHcO_(3), while H_(2) from the competitive water reduction appears at larger overpotentials(-0.9 V vs. RHE). The optimum copper acetate-derived catalyst containing cu-N_(4) moieties exhibits a cO_(2)-to-cO turnover frequency of 997 h^(-1) at -0.9 V vs. RHE with a H_(2)/cO ratio of 1.8. These results demonstrate that RRDE configuration can be used as a feasible approach for identifying electrolysis products from cO_(2)RR.

关键词： cu-N-c carbon xerogel Rotating ring disc electrode carbon dioxide reduction reaction carbon monoxide

Roller Screw and Threaded chain Speed Reducer: An Experimental Evaluation

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Modern Mechanical Engineering 2024年第1期14卷 1-11页

作者： Filiberto gutiérrez Instituto de Ingeniería Universidad Nacional Autónoma de México Mexico City Mexico

We are developing a speed reducer that can be considered a transformation of a worm gear reducer: the worm is replaced by an inverted roller screw, and the gear is replaced by a threaded chain drive. This configuration lessens wear, increases load capacity, and improves efficiency. The threaded chain consists of nut-shaped links. This paper presents the results of tests carried out on a prototype with a reduction ratio of 46.

关键词： Speed Reducer Inverted Roller Screw chain Drive Threaded chain Drive

THE SUMERIAN TERM u_(8)/ud_(5)/ab_(2)/eme_(3)/_(6)sila_(4)/maš_(2)/amar du_(3)(-a)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Ancient civilizations 2024年第1期39卷 1-28,123页

作者： marcos Such-gutiérrez Facultad de Filosofía y Letras Universidad Autónoma de Madrid

The aim of the present article is twofold:firstly,to prove that the expression animal+young du_(3)(-a),which is basically documented in texts from the 3rd millennium Bc,refers to a dam that has just given birth,and se... 详细信息

关键词： 3rd millennium Bc female animal+young du_(3)(-a) livestock newborn suckling animal UrⅢperiod

Latest developments in early diagnosis and specific treatment of severe influenza infection

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Intensive Medicine 2024年第2期4卷 160-174页

作者： Francisco Valenzuela-Sánchez Blanca Valenzuela-Méndez Juan Francisco Rodríguez-gutiérrez Ángel Estella Intensive care Unit University Hospital of JerezRonda de Circunvalación s/nJerez de la FronteraSpain Haematology Department University Hospital of JerezRonda de Circunvalación s/nJerez de la FronteraSpain centro de Investigación Biomédica en Red Enfermedades respiratoriasCIBERESInstituto de Salud Carlos IIIAv.de Monforte de LemosMadridSpain Department of Oncological Surgery Institut du Cancer de Montpellier(ICM)Parc Euromédecine208 Av.des ApothicairesMontpellierFrance Department of Medicine Faculty of MedicineUniversity of CádizCalle Doctor MarañónCádizSpain Instituto de Investigación e Innovación Biomédica de cádiz(INIBicA) Avenida Ana de Viya 21CádizSpain

Influenza pandemics are unpredictable recurrent events with global health,economic,and social *** objective of this review is to provide an update on the latest developments in early diagnosis and specific treatment of the disease and its complications,particularly with regard to respiratory organ *** advances in treatment,the rate of mortality in the intensive care unit remains approximately 30%.Therefore,early identification of potentially severe viral pneumonia is extremely important to optimize treatment in these *** pathogenesis of influenza virus infection depends on viral virulence and host ***,in some patients,it is associated with an excessive systemic response mediated by an authentic cytokine *** process leads to severe primary pneumonia and acute respiratory distress *** prognostication in the emergency department based on comorbidities,vital signs,and biomarkers(e.g.,procalcitonin,ferritin,human leukocyte antigen-DR,mid-regional proadrenomedullin,and lactate)is *** of these biomarkers on admission may facilitate clinical decision-making to determine early admission to the hospital or the intensive care *** decisions are reached considering pathophysiological circumstances that are associated with a poor prognosis(e.g.,bacterial co-infection,hyperinflammation,immune paralysis,severe endothelial damage,organ dysfunction,and septic shock).Moreover,early implementation is important to increase treatment *** on a limited level of evidence,all current guidelines recommend using oseltamivir in this *** possibility of drug resistance should also be *** options include other antiviral drugs and combination therapies with monoclonal ***,it is not recommended to use corticosteroids in the initial treatment of these ***,the implementation of supportive measures for respiratory failure is ***

关键词： Influenza Pandemic Respiratory failure Acute respiratory distress syndrome Intensive care unit admission

Metal-modulated epitaxy of Mg-doped Al_(0.80)In_(0.20)N-based layer for application as the electron blocking layer in deep ultraviolet light-emitting diodes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Semiconductors 2024年第5期45卷 80-89页

作者： Horacio Irán Solís-cisneros carlos Alberto Hernández-gutiérrez Enrique campos-González Máximo López-López Optomechatronics Group Tecnológico Nacional de México Campus Tuxtla Gutiérrezcarretera Panamericana 1080C.P.29050Tuxtla GutiérrezChiapasMéxico Departamento de Física Instituto Nacional de Investigaciones NuclearesCarretera México-Toluca s/nC.P.52750La Marquesa OcoyoacacMéxico Departamento de Física Centro de Investigación y estudios Avanzados del Instituto Politécnico NacionalAv.Instituto Politécnico Nacional 2508San Pedro ZacatencoGustavo A.Madero07360 Ciudad de MéxicoCDMXMéxico

This work reports the growth and characterization of p-AlInN layers doped with Mg by plasma-assisted molecular beam epitaxy(PAMBE).AlInN was grown with an Al molar fraction of 0.80 by metal-modulated epitaxy(MME)with a thickness of 180 nm on Si(111)substrates using AlN as buffer *** substrate temperatures were used to enhance the incorporation of indium atoms into the alloy without clustering,as confirmed by X-ray diffraction(XRD).cathodoluminescence measurements revealed ultraviolet(UV)range ***,Hall effect measurements indicated a maximum hole mobility of 146 cm^(2)/(V∙s),corresponding to a free hole concentration of 1.23×10^(19)cm^(−3).The samples were analyzed by X-ray photoelectron spectroscopy(XPS)estimating the alloy composition and extracting the Fermi level by valence band ***-doped AlInN layers were studied for use as the electron-blocking layer(EBL)in LED *** varied the Al composition in the EBL from 0.84 to 0.96 molar fraction to assess its theoretical effects on electroluminescence,carrier concentration,and electric field,using SILVAcO *** results from this study highlight the importance and capability of producing high-quality Mg-doped p-AlInN layers through *** simulations suggest that an Al content of 0.86 is optimal for achieving desired outcomes in electroluminescence,carrier concentration,and electric field.

关键词： metal-modulated epitaxy AlInN DUV-LED EBL simulation

A Probabilistic Description of the Impact of Vaccine-Induced Immunity in the Dynamics of cOVID-19 Transmission

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Open Journal of Modelling and Simulation 2024年第2期12卷 59-73页

作者： Javier Blecua Juan Fernández-Recio José Manuel gutiérrez Instituto de ciencias de la Vid y del Vino (IcVV) CSIC-Universidad de La Rioja-Gobierno de La Rioja Logro&#241o Spain Departamento de Matemá ticas y Computaci&#243n Universidad de La Rioja Logro&#241o Spain

The recent outbreak of cOVID-19 has caused millions of deaths worldwide and a huge societal and economic impact in virtually all countries. A large variety of mathematical models to describe the dynamics of cOVID-19 transmission have been reported. Among them, Bayesian probabilistic models of cOVID-19 transmission dynamics have been very efficient in the interpretation of early data from the beginning of the pandemic, helping to estimate the impact of non-pharmacological measures in each country, and forecasting the evolution of the pandemic in different potential scenarios. These models use probability distribution curves to describe key dynamic aspects of the transmission, like the probability for every infected person of infecting other individuals, dying or recovering, with parameters obtained from experimental epidemiological data. However, the impact of vaccine-induced immunity, which has been key for controlling the public health emergency caused by the pandemic, has been more challenging to describe in these models, due to the complexity of experimental data. Here we report different probability distribution curves to model the acquisition and decay of immunity after vaccination. We discuss the mathematical background and how these models can be integrated in existing Bayesian probabilistic models to provide a good estimation of the dynamics of cOVID-19 transmission during the entire pandemic period.

关键词： cOVID-19 Transmission Dynamics Probabilistic Model Bayesian Analysis markov chain Monte carlo

Experimental implementation of phase triplicator gratings in a spatial light modulator

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

chinese Optics Letters 2024年第2期22卷 64-69页

作者：高尚 maría del mar Sánchez-López Ignacio Moreno Instituto de Bioingeniería Universidad Miguel HernándezElche 03202Spain Departamento de Física Aplicada Universidad Miguel HernándezElche 03202Spain Departamento de ciencia de Materiales Óptica y Tec.Electr´onicaUniversidad Miguel HernándezElche 03202Spain

In this work,we compare different methods for implementing a triplicator,a phase grating that generates three equiintense diffraction *** design with optimal efficiency features a continuous phase profile,which cannot be easily reproduced,and is typically affected by *** compare its performance with binary and sinusoidal phase *** also analyze the effect of quantizing the phase ***,a random approach is adopted to eliminate the additional harmonic *** all cases,a liquid-crystal-on-silicon spatial light modulator is employed to experimentally verify and compare the different approaches.

关键词： diffraction gratings phase modulation triplicator spatial light modulators

Body contour in the Post-Bariatric Male Patient

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Modern Plastic Surgery 2024年第2期14卷 15-22页

作者： Erick Zúñiga-Garza Israel Salgado-Adame claudio D. Rojas-gutiérrez Laura maría Rodríguez-Barrios Guillermo Álvarez-Sánchez Eduardo camacho-Quintero Department of Plastic Surgery National Medical Center &#822020 de Noviembre&#8221 Mexico City Mexico

Background: Obesity is currently considered a public health problem. Bariatric procedures have become an important part of obesity management and, consequently, the number of male patients seeking post-bariatric reconstructive procedures have increased. Therefore, the clinical approach and understanding of the body contour of this population have become more relevant. The goal of post-bariatric reconstruction is to enhance the male silhouette through removal of skin and adipose tissue excess, and abdominal rectus diastasis repair. Material and Methods: We conducted a retrospective study at the Plastic and Reconstructive Surgery Department of the National Medical center “20 de Noviembre”. All male patients referred to our department to start a post-bariatric reconstruction protocol from January 2018 to December 2022 were included in this study. Results: In total, 15 patients who underwent corporal contouring procedures were included;median age was 49.2 years with minimum of 33 years, and a maximum of 57 years. Median Body mass index was 28.4 kg/m2 with minimum of 22 kg/m2 and maximum of 38 kg/m2. All patients were treated 18 months after their bariatric surgery. All patients underwent an abdominoplasty as a body contouring procedure. 4 (26.7%) patients presented complications related to the surgery. conclusion: We described a comprehensive and systematic approach to massive weight loss for male patients, suggesting an abdominal marking based on the patient’s clinical features and the expected results avoiding feminization of the abdominal body contour.

关键词： Massive Weight Loss Post-Bariatric Male Abdominoplasty contouring