检索结果-南通市图书馆

Optimal Tuning of FOPID-Like Fuzzy Controller for High-Performance Fractional-Order Systems

在线全文

学校读者我要写书评

暂无评论

Computers, materials & Continua 2022年第1期70卷 171-180页

作者： Ahmed m.Nassef Hegazy Rezk College of Engineering at Wadi Addawaser Prince Sattam Bin Abdulaziz UniversityAl-Kharj11911Saudi Arabia Department of Computers and Automatic Control Engineering Faculty of EngineeringTanta UniversityTanta31733Egypt Department of Electrical Engineering Faculty of EngineeringMinia UniversityMinia61517Egypt

This paper addresses improvements in fractional order(FO)system *** the classical proportional-integral-derivative(PID)-like fuzzy controller can provide adequate results for both transient and steady-state responses in both linear and nonlinear systems,the FOPID fuzzy controller has been proven to provide better *** high performance was obtained thanks to the combinative benefits of FO and fuzzy-logic *** paper describes how the optimal gains and FO parameters of the FOPID controller were obtained by the use of a modern optimizer,social spider optimization,in order to improve the response of fractional dynamical *** group of systems had usually produced multimodal error surfaces/functions that occasionally had many variant local *** integral time of absolute error(ITAE)used in this study was the error *** results showed that the strategy adopted produced superior performance regarding the lowest ITAE *** reached a value of 88.22 while the best value obtained in previous work was 98.87.A further comparison between the current work and previous studies concerning transient-analysis factors of the model’s response showed that the strategy proposed was the only one that was able to produce fast rise time,low-percentage overshoot,and very small steady-state ***,the other strategies were good for one factor,but not for the others.

关键词： Fuzzy-logic control fractional-order systems parameter estimation optimization

Actin(g) toward a revised understanding of the role of cytoskeletal dynamics in neuronal bioenergetics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2024年第10期19卷 2109-2110页

作者： Sabrina m.Holland Gianluca Gallo Department of Neural Sciences Shriners Pediatric Research CenterLewis Katz School of Medicine at Temple UniversityPhiladelphiaPAUSA

Neurons are energy-demanding *** in energy metabolism can quickly interrupt neuronal function,leading to cell death and *** instance,ischemia rapidly depletes adenosine triphosphate(ATP)thereby disrupting energy-dependent cellular processes crucial for homeostasis,and axon degeneration is preceded by a collapse of axonal ATP levels.

关键词： metabolism homeostasis degeneration

Temporal niche overlap among insectivorous small mammals

在线全文

学校读者我要写书评

暂无评论

Integrative Zoology 2011年第4期6卷 375-386页

作者： Emerson m.VIEIRA Gabriela PAISE Laboratory of Ecology of mammals ZoologyUniversity of Vale do Rio dos SinosSão LeopoldoBrazil Graduate Program of Ecology University of CampinasCampinasBrazil

Being active in the same environment at different times exposes animals to the effects of very different environmental factors,both biotic and *** the present study,we used live traps equipped with timing devices to evaluate the potential role of biotic factors(competition and food abundance)on overall overlap in the temporal niche axis of 4 insectivorous small mammals in high-elevation grassland fields(‘campos de altitude’)of southern *** on resources availability(invertebrates),data on animal captures were pooled in 2 seasons:‘scarcity’(June 2001−September 2001)and‘abundance’(November 2001-may 2002)*** tested for non-random structure in temporal niche overlap among the species in each *** species were the rodents Oxymycterus nasutus(Waterhouse,1837),Deltamys sp.,Akodon azarae(Fischer,1829),and the marsupial monodelphis brevicaudis Olfers,*** studied community was mainly diurnal with crepuscular *** using the Pianka index of niche overlap indicated that the empirical assemblage-wide overlap was not significantly different from randomly generated patterns in the abundance season but significantly greater than expected by chance alone in the scarcity *** the species showed an increase in temporal niche breadth during the abundance season,which appears to be related to longer daylength and high nocturnal *** on both temporal niche overlap and temporal niche breadth were the opposite to those that we were expecting in the case of diel activity patterns determined by competition for dietary ***,we conclude that competition did not seem to be preponderant for determining patterns of temporal niche overlap by the studied community.

关键词： activity patterns Brazil chronoecology community structure competition niche partitioning

Contrast enhancement of medical ultrasound imaging with reversal phase-inversion pulse technology

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 Central South university 2013年第3期20卷 696-701页

作者：李琴谭冠政 A.S.m.Libda School of Information Science and Engineering Central South University

A new ultrasound contrast imaging technique was proposed for eliminating the harmonic components from the emission signal transmitted by the broadband ultrasonic *** phase-inversion pulse was used for the first time to separate the contrast harmonics from the harmonics in the emission signal to improve the detection of contrast *** on the nonlinear acoustic theory of finite-amplitude effects and the associated distortion of the propagating wave,the Bessel-Fubini series model was applied to describe the nonlinear propagation effects of the reversal phase-inversion pulse,and the Church's equation for zero-thickness encapsulation model was used to produce the scattering-pulse of the *** harmonic imaging,the experiment was performed using a 64-element linear array,which was simulated by Field *** results show that the harmonic components from the emission signal can be completely cancelled,and the harmonics generated by the nonlinear propagation of the wave through the tissue,can be reduced by 15-30 *** with the short pulse,the reversal phase-inversion pulse can improve the contrast and definition of the harmonic image significantly.

关键词： reversal pulse phase inversion Church model ultrasound imaging contrast

Recovery of spermatogenesis following testosterone replacement therapy or anabolic-androgenic steroid use

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2016年第3期18卷 373-380,I0007页

作者： J Abram mcBride Robert m Coward Department of urology University of North Carolina School of Medicine Chapel Hill NC 27599-7235 USA.

The use of testosterone replacement therapy （TRT） for hypogonadism continues to rise, particularly in younger men who may wish to remain fertile. Concurrently, awareness of a more pervasive use of anabolic-androgenic steroids （AAS） within the general population has been appreciated. Both TRT and AAS can suppress the hypothalamic-pituitary-gonadal （HPG） axis resulting in diminution of spermatogenesis. Therefore, it is important that clinicians recognize previous TRT or AAS use in patients presenting for infertility treatment. Cessation of TRT or AAS use may result in spontaneous recovery of normal spermatogenesis in a reasonable number of patients if allowed sufficient time for recovery. However, some patients may not recover normal spermatogenesis or tolerate waiting for spontaneous recovery. In such cases, clinicians must be aware of the pathophysiologic derangements of the HPG axis related to TRT or AAS use and the pharmacologic agents available to reverse them. The available agents include injectable gonadotropins, selective estrogen receptor modulators, and aromatase inhibitors, but their off-label use is poorly described in the literature, potentially creating a knowledge gap for the clinician. Reviewing their use clinically for the treatment of hypogonadotropic hypogonadism and other HPG axis abnormalities can familiarize the clinician with the manner in which they can be used to recover spermatogenesis after TRT or AAS use.

关键词： anabolic steroids hypogonadism infertility spermatogenesis testosterone testosterone replacement therapy vasectomy reversal

The Fine Spectra of the Difference Operator △ Over the Sequence Space bv_p,(1≤p<∞)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta mathematica Sinica,English Series 2007年第10期23卷 1757-1768页

作者： Ali m.AKHmEDOV Feyzi BASAR Baku State university Department of Mech.& Math.Z.Khalilov Str.23P.O.Box 370145BakuAzerbaijan nOnü universitesi Eitim FakültesiMatematik Eitimi BOlümüMalatya-44280

The sequence space bvp consisting of all sequences （xk） such that （xk -xk-1） belongs to the space gp has recently been introduced by Basar and Altay [ukrainian math. J., 55（1）, 136-147（2003）]; where 1 ≤ p ≤ ∞. In the present paper, some results concerning with the continuous dual and f-dual, and the AD-property of the sequence space bvp have been given and the norm of the difference operator A acting on the sequence space bvp has been found. The fine spectrum with respect to the Goldberg＇s classification of the difference operator △ over the sequence space bvp has been determined, where 1≤p〈∞.

关键词： spectrum of an operator difference operator the continuous dual and f-dual of a sequence space the AD-property and the sequence space bvp

Energy Bounds for Static Spherically Symmetric Spacetime in f(R, G) Gravity

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2018年第8期69卷 190-196页

作者： m.Farasat Shamir Ayesha Komal Department of Sciences and Humanities National University of Computer and Emerging Sciences

The main purpose of this paper is to investigate energy bounds in the context of f(R, G) gravity. To meet this aim, we choose static spherically symmetric spacetime in f(R, G) gravity to develop the field equations. We select three different models of f(R, G) gravity, which are thoroughly discussed in the literature. Firstly, the inequalities are formulated using energy bounds and then viability of the considered models are checked respectively. Graphical analysis show that specific f(R, G) gravity models are satisfied under suitable values of model parameters. It is shown that in a certain case energy bounds are satisfied expect SEC, which supports the late time acceleration expansion of unverse.

关键词： energy bounds f(R G) gravity

Emerging Perspectives on the mechanisms, Regulation, and Distribution of Light Color Acclimation in Cyanobacteria

在线全文

学校读者我要写书评

暂无评论

molecular Plant 2012年第1期5卷 1-13页

作者： Andrian Gutu David m. Kehoe Department of Biology 1001 East Third Street indiana University Bloomington iN 47405 USA Present address： HoWard Hughes medical Institute/Department Of molecular and Cellular Biology FAS Center for Systems Biology Harvard UniversityCambridge MA 02138 USA

Chromatic acclimation （CA） provides many cyanobacteria with the ability to tailor the properties of their light-harvesting antennae to the spectral distribution of ambient light. CA was originally discovered as a result of its dramatic cellular phenotype in red and green light. However, discoveries over the past decade have revealed that many pairs of light colors, ranging from blue to infrared, can trigger CA responses. The capacity to undergo CA is widespread geographically, occurs in most habitats around the world, and is found within all major cyanobacterial groups. In addition, many other cellular activities have been found to be under CA control, resulting in distinct physiological and morphological states for cells under different light-color conditions. Several types of CA appear to be the result of convergent evolution, where different strategies are used to achieve the final goal of optimizing light-harvesting antenna composition to maximize photon capture. The regulation of CA has been found to occur primarily at the level of RNA abundance. The CA-regulatory pathways uncovered thus far are two-component systems that use phytochrome-class photoreceptors with sensor-kinase domains to control response regulators that function as transcription factors. However, there is also at least one CA- regulatory pathway that operates at the post-transcriptional level. It is becoming increasingly clear that large numbers of cyanobacterial species have the capacity to acclimate to a wide variety of light colors through the use of a range of different CA processes.

关键词： Chromatic adaptation phycobilisome cyanobacteria light regulation gene regulation signal transduction light harvesting phenotypic plasticity.

EFFECTS OF EXTERNAL DONOR ON ACTIVE CENTER DISTRIBuTION OF SuPPORTED ZIEGLER-NATTA CATALYST

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 Journal of Polymer Science 1997年第3期15卷 217-225页

作者：范志强 m.CarmelaSacchi PaoloLocatelli Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027 Istituto di Chimica delle macromolecole CNR 20133 Milan Italy

The composition distribution (CD) and microisotacticity distribution (ID) of propene/1-hexene copolymer synthesized by mgCl2/DIBP/TiCl4 (DIBP: diisobutyl phthalate) were determined by fractionating the copolymers according to crystallinity and characterizing the fractions by (CNmR)-C-13. The effects of two alkoxysilane donors, triethoxyphenylsilane (PTES) and dimethoxydi-tert-butylsilane (TBmS), on CD and ID of the copolymers were compared. Three main parts in the CD diagram of each copolymer were distinguished, which were correlated to active center distribution (ACD) based on three groups of different active centers. By studying the changes in l-hexene content, microisotacticity and reactivity ratio product of three typical fractions, the effects of external donor on ACD were better elucidated. It was found that TBmS shows much stronger effects on ACD than PTES. In the former system, most fractions were produced on active centers with relatively lower r(1)r(2), higher reactivity to I-hexene, and higher stereospecificity as compared to the system without external donor. It is concluded that the observed very extensive changes in ACD are mainly resulted by the formation of new types of active centers, possibly by coordination of external donor to certain positions on the catalyst.

关键词： supported Ziegler-Natta catalyst propene/1-hexene copolymer external donor active center distribution