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排序方式: 共有1221条查询结果,搜索用时 171 毫秒
51.
Luca Damilano Giorgio Guglieri Fulvia Quagliotti Ilaria Sale 《Journal of Intelligent and Robotic Systems》2012,65(1-4):27-42
To integrate UASs in the NAS, an improvement in navigation, planning, communication and 4D trajectory control capabilities is mandatory. A way to obtain this enhance is to adopt a Flight Management System. A FMS for an UAS has some differences with respect to one for a manned aircraft, in terms of architecture and performed functions. In particular, from HMI point of view, the specific UAS human factor issues shall be added to the current manned FMS interface lacks. Starting from these considerations, a new FMS HMI for the Alenia Aeronautica TCS has been developed, using as data entry devices two touch screens. 相似文献
52.
Nevio Luigi Tagliamonte Fabrizio Sergi Dino Accoto Giorgio Carpino Eugenio Guglielmelli 《Mechatronics》2012,22(8):1187-1203
Novel compliant actuation systems have been developed in recent years for a variety of possible advantages, such as establishing a safe human–robot interaction, increasing energy efficiency, reducing the effects of impacts and even for the development of neuro-inspired robotic platforms to be used in human motor control studies.In this rapidly growing and transversal research field, systems involving more than one active element (typically motors) for each actuated degree of freedom are being investigated to allow separate position and impedance regulations. Considering the wide range of applications and the large number of different arrangements deriving from the combination of two active elements and passive elastic components, several actuation architectures have been devised.This paper reviews state-of-the-art rotary variable impedance units incorporating two separate motors. Existing devices are grouped in three main categories. A critical and comparative analysis of the most relevant features is carried out, also based on most representative prototypes. Recently proposed methodologies and evaluation criteria for design optimization are illustrated and perspectives on potential applications of double actuation systems are presented. 相似文献
53.
The theory of variational integration provides a systematic procedure to discretize the equations of motion of a mechanical system, preserving key properties of the continuous time flow. The discrete-time model obtained by variational integration theory inherits structural conditions which in general are not guaranteed under general discretization procedures. We discuss a simple class of variational integrators for linear second order mechanical systems and propose a constrained identification technique which employs simple linear transformation formulas to recover the continuous time parameters of the system from the discrete-time identified model. We test this approach on a simulated eight degrees of freedom system and show that the new procedure leads to an accurate identification of the continuous-time parameters of second-order mechanical systems starting from discrete measured data. 相似文献
54.
Mulloni Viviana Margesin Benno Farinelli Paola Marcelli Romolo Lucibello Andrea De Angelis Giorgio 《Microsystem Technologies》2017,23(9):3843-3850
Microsystem Technologies - Contact resistance is the main parameter used for assessing the high cycling reliability of RF microelectromechanical (RF-MEMS) switches. In this paper the use of a... 相似文献
55.
Zlatica Marinkovi Giovanni Crupi Alina Caddemi Gustavo Avolio Antonio Raffo Vera Markovi Giorgio Vannini Dominique M. M.‐P. Schreurs 《International Journal of Numerical Modelling》2015,28(4):359-370
Gallium nitride high electron‐mobility transistors have gained much interest for high‐power and high‐temperature applications at high frequencies. Therefore, there is a need to have the dependence on the temperature included in their models. To meet this challenge, the present study presents a neural approach for extracting a multi‐bias model of a gallium nitride high electron‐mobility transistors including the dependence on the ambient temperature. Accuracy of the developed model is verified by comparing modeling results with measurements. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
56.
Pietro Russo Giorgio Simeoli Domenico Acierno Valentina Lopresto 《Polymer Composites》2015,36(11):2022-2029
Polyolefin‐based composite laminates reinforced with jute fabric were prepared by compression molding and investigated in terms of flexural properties and impact behavior. The use of a virgin polypropylene as the matrix was compared with two polyolefin matrices coming from discarded car bumpers and selected packaging wastes, respectively, and mainly constituted by mixtures of polyethylene and polypropylene resins. The influence of a coupling agent (maleated polypropylene) was always considered in order to improve the interfacial adhesion and, consequently, the composite strength. The effect of this coupling agent, clearly dependent on the amount of polypropylene phase in the overall mixture, was found to be satisfactory only in the case of virgin polypropylene‐based systems. These latter, in presence of maleated polypropylene, have shown higher flexural parameters, lower propagation energy and higher breaking impact load with respect to uncompatibilized ones. Results were supported by morphological observations of impact surfaces, always highlighting a poor adhesion at the reinforcement–matrix interface except in compatibilized virgin polypropylene‐based laminates. POLYM. COMPOS., 36:2022–2029, 2015. © 2014 Society of Plastics Engineer 相似文献
57.
Alessandro Marchioni Roberto Tonelli Alessandro Andreani Gaia Francesca Cappiello Matteo Fermi Fabiana Trentacosti Ivana Castaniere Riccardo Fantini Luca Tabbì Dario Andrisani Filippo Gozzi Giulia Bruzzi Linda Manicardi Antonio Moretti Serena Baroncini Anna Valeria Samarelli Massimo Pinelli Giorgio De Santis Alessandro Stefani Daniele Marchioni Francesco Mattioli Enrico Clini 《International journal of molecular sciences》2022,23(5)
Laryngotracheal stenosis (LTS) is a complex and heterogeneous disease whose pathogenesis remains unclear. LTS is considered to be the result of aberrant wound-healing process that leads to fibrotic scarring, originating from different aetiology. Although iatrogenic aetiology is the main cause of subglottic or tracheal stenosis, also autoimmune and infectious diseases may be involved in causing LTS. Furthermore, fibrotic obstruction in the anatomic region under the glottis can also be diagnosed without apparent aetiology after a comprehensive workup; in this case, the pathological process is called idiopathic subglottic stenosis (iSGS). So far, the laryngotracheal scar resulting from airway injury due to different diseases was considered as inert tissue requiring surgical removal to restore airway patency. However, this assumption has recently been revised by regarding the tracheal scarring process as a fibroinflammatory event due to immunological alteration, similar to other fibrotic diseases. Recent acquisitions suggest that different factors, such as growth factors, cytokines, altered fibroblast function and genetic susceptibility, can all interact in a complex way leading to aberrant and fibrotic wound healing after an insult that acts as a trigger. However, also physiological derangement due to LTS could play a role in promoting dysregulated response to laryngo-tracheal mucosal injury, through biomechanical stress and mechanotransduction activation. The aim of this narrative review is to present the state-of-the-art knowledge regarding molecular mechanisms, as well as mechanical and physio-pathological features behind LTS. 相似文献
58.
Some hearing, vestibular, and vision disorders are imputable to voltage-gated Ca2+ channels of the sensory cells. These channels convey a large Ca2+ influx despite extracellular Na+ being 70-fold more concentrated than Ca2+; such high selectivity is lost in low Ca2+, and Na+ can permeate. Since the permeation properties and molecular identity of sensory Ca2+ channels are debated, in this paper, we examine the Na+ current flowing through the L- and R-type Ca2+ channels of labyrinth hair cells. Ion currents and cytosolic free Ca2+ concentrations were simultaneously monitored in whole-cell recording synchronous to fast fluorescence imaging. L-type and R-type channels were present with different densities at selected sites. In 10 nM Ca2+, the activation and deactivation time constants of the L-type Na+ current were accelerated and its maximal amplitude increased by 6-fold compared to physiological Ca2+. The deactivation of the R-type Na+ current was not accelerated, and its current amplitude increased by 2.3-fold in low Ca2+; moreover, it was partially blocked by nifedipine in a voltage- and time-dependent manner. In conclusion, L channel gating is affected by the ion species permeating the channel, and its selectivity filter binds Ca2+ more strongly than that of R channel; furthermore, external Ca2+ prevents nifedipine from perturbing the R selectivity filter. 相似文献
59.
Ilaria Barchetta Marco Giorgio Baroni Olle Melander Maria Gisella Cavallo 《International journal of molecular sciences》2022,23(4)
Neurotensin (NT) is a small peptide with pleiotropic functions, exerting its primary actions by controlling food intake and energy balance. The first evidence of an involvement of NT in metabolism came from studies on the central nervous system and brain circuits, where NT acts as a neurotransmitter, producing different effects in relation to the specific region involved. Moreover, newer interesting chapters on peripheral NT and metabolism have emerged since the first studies on the NT-mediated regulation of gut lipid absorption and fat homeostasis. Intriguingly, NT enhances fat absorption from the gut lumen in the presence of food with a high fat content, and this action may explain the strong association between high circulating levels of pro-NT, the NT stable precursor, and the increased incidence of metabolic disorders, cardiovascular diseases, and cancer observed in large population studies. This review aims to provide a synthetic overview of the main regulatory effects of NT on several biological pathways, particularly those involving energy balance, and will focus on new evidence on the role of NT in controlling fat homeostasis, thus influencing the risk of unfavorable cardio–metabolic outcomes and overall mortality in humans. 相似文献
60.
Nadia Giarratana Luciana Giardino Andrea Bighinati Giorgio Reiner Júlio Csar Rocha 《International journal of molecular sciences》2022,23(4)
Phenylketonuria (PKU) is a rare autosomal recessive inborn error of metabolism where the mainstay of treatment is a Phe restricted diet consisting of a combination of limited amounts of natural protein with supplementation of Phe-free or low-Phe protein substitutes and special low protein foods. Suboptimal outcomes may be related to the different absorption kinetics of free AAs, which have lower biological efficacy than natural proteins. Physiomimic TechnologyTM is a technology engineered to prolong AA (AA-PT) release allowing physiological absorption and masking the odor and taste of free AAs. The aim of these studies was to assess the impact of AA-PT formulation on selected functional and metabolic parameters both in acute and long-term experimental studies. Adult rats in fasting conditions were randomized in different groups and treated by oral gavage. Acute AA-PT administration resulted in significantly lower BUN at 90 min versus baseline. Both BUN and glycemia were modulated in the same direction as intact casein protein. Long-term treatment with AA-PT significantly reduces the protein expression of the muscle degradation marker Bnip3L (−46%) while significantly increasing the proliferation of market myostatin (+58%). Animals dosed for 15 days with AA-PT had significantly stronger grip strength (+30%) versus baseline. In conclusion, the results suggest that the AA-PT formulation may have beneficial effects on both AA oxidation and catabolism with a direct impact on muscle as well as on other metabolic pathways. 相似文献