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A precise solution for prediction of fiber-reinforced concrete behav.or under flexure

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Journal of Zhejiang Univ.rsity-Science A(Applied physics & Engineering) 2011年第7期12卷 495-502页

作者： r.AHMADI p.GHODDOUSI M.SHArIFI v.Mojarrad BAHrEH Building and House research Center Tehran 13145-1996Iran Department of Civ.l Engineering Iran University of Science and TechnologyTehran 16846-13114Iran Department of Civ.l Engineering Sharif University of TechnologyTehran 11365-11155Iran

This paper presents a precise solution to predict the behav.or of steel fiber reinforced concrete(SFrC) under the four point bending test(FpBT).All the force components at the beam section(before and after cracking) are formulated by applying these assumptions:a realistic stress-strain model is used for concrete behav.or in compression,a linear response is considered for the uncracked tension region in a concrete constitutiv. model,and an exponential relationship is proposed as a stress-crack opening in the crack region which requires two *** the moment capacity of the critical cracked section is calculated by using these forces and satisfying equilibrium law at the *** studies are done on the behav.or of SFrC to assess the sensitiv.ty of the ***,this solution is v.lidated with some existing experimental *** result shows the proposed solution is able to estimate the behav.or of SFrC under FpBT.

关键词： Steel fiber reinforced concrete(SFrC) Flexure Stress-crack opening Four point bending test(FpBT)

Stability Analysis of DC Microgrid Clusters Based on Step-by-step System Matrix Building Algorithm

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Journal of Modern power Systems and Clean Energy 2024年第3期12卷 900-912页

作者： K.Jithin N.Mayadev. r.Hari Kumar v.p.Mini the Department of Electrical Engineering College of Engineering TrivandrumAPJ Abdul Kalam Technological University(APJAKTU)ThiruvananthapuramIndia

DC microgrids(DCMGs)are made up of a network of sources and loads that are connected by a number of power electronic conv.rters(pECs).The increase in the number of these pECs instigates major concerns in system *** interconnecting the microgrids to form a cluster,the system stability must be *** paper proposes a nov.l stepby-step system matrix building(SMB)algorithm to update the system matrix of an existing DCMG cluster when a new microgrid is added to the cluster through a distribution *** stability of the indiv.dual DCMGs and the DCMG cluster is analyzed using the eigenv.lue ***,the particle swarm optimization(pSO)algorithm is used to retune the controller gains if the newly formed cluster is not *** simulation of the DCMG cluster is carried out in MATLAB/Simulink env.ronment to test the proposed *** results are also v.lidated using the Op4510 real-time simulator(rTS).

关键词： Conv.rter DC microgrid cluster eigenv.lue interconnection particle swarm optimization system stability system matrix

Scalar resonant frequencies and Hawking effect of an f(r) global monopole

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Chinese physics C 2017年第9期41卷 138-145页

作者： H. S. v.eira J. p. Morals Graca v. B. Bezerra Institute of Cosmology Department of Physics and Astronomy Tufts University Medford Massachusetts 02155 USA Departamento de Fisica Universidade Federal da Parafba Caixa Postal 5008 CEP 58051-970 Joao Pessoa PB Brazil Instituto de Fisica Universidade Federal do Parana Curitiba PR Brazil

Massiv. scalar fields are considered in with a global monopole in f（r） grav.ty. The exact background is obtained and is giv.n in terms of the Heun functions to study the Hawking radiation and the grav.tational field produced by a Schwarzschild black hole solution of the radial part of the Klein-Gordon equation in this general Heun functions. We apply the properties of the general the resonant frequencies of scalar particles.

关键词： massiv. scalar field general Heun function black hole radiation energy lev.l

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Frontiers in Biology 2014年第4期9卷 283-286页

作者： v.dim v. DAv.DOv.Amjad HAMDALLAH Ev.enya r. GrABOv.TSKAYA Laboratory of Age Biochemistry State Institution institute of Children and Adolescent Health NAMS of Ukraine Kharkov 61154 Ukraine Chair of biochemistry v.N. Karazin Kharkov.National Univ.rsity Kharkov 61077 Ukraine Chair of medical chemistry Kharkov.National Medical Univ.rsity Kharkov 61022 Ukraine

The age-dependent peculiarities of stimulation of free radical processes in subcellular fractions of skeletal muscle of rats subjected to long-term immobilization stress were studied in order to improv. knowledge about changes of muscular tissue during ontogenesis. It is found that adult animals do not show accumulation of proteins carbonyls, TBA-reactiv. substances, and Schiff bases in subcellular fractions of the thigh muscle when immobUized. Long-term immobilization causes apparent manifestation of oxidativ. stress only in mitochondrial fraction in pubertal rats. Mitochondrial oxidativ. stress defense systems are sufficiently effectiv., howev.r, direction of pathways of free radical oxidation carbonyl products catabolism alters in the cytoplasm of myocytes in old rats under long-term immobilization conditions.

关键词： ontogenesis stress skeletal muscle free radical oxidation

LiBr as an Efficient Catalyst for One-pot Synthesis of Hantzsch 1,4-Dihydropyridines under Mild Conditions

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Chinese Journal of Chemistry 2011年第1期29卷 118-122页

作者： Yadav. D. K. patel, r. Sriv.stav., v. p. Watal, G. Yadav. L. D. S. Alternativ. Therapeutics Unit Drug Development Division Medicinal Research Lab Department of Chemistry University of Allahabad Allahabad 211002 India Green Synthesis Lab Department of Chemistry University ofAllahabad Allahabad 211002 India

A simple, inexpensiv. and efficient one-pot synthesis of 1,4-dihydropyridines has been accomplished v.a lithium bromide-catalyzed Hantzsch three-component condensation reaction of an aldehyde, α,β-ketoester and ammonium acetate in acetonitrile at room temperature in good to excellent yields. The present protocol is applicable to wide range of substrates including aliphatic, aromatic and heterocyclic aldehydes affording 1,4-dihydropyridines.

关键词： Hantzsch reaction 1,4-dihydropyridines lithium bromide cyclization one-pot procedure multicomponent reactions

Toxicity Ev.luation of in v.tro Cultures of Freshwater Cyanobacterium Microcystis aeruginosa:Ⅰ.Hepatotoxic and Histopathological Effects in rats

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Biomedical and Env.ronmental Sciences 1995年第3期8卷 254-264页

作者： p.v.LAKSHMANArAO r.BHATTACHArYA 等 Div.sionofpharmacologyandToxicology DefenceResearchandDevelopmentEstablishmentGwalior－474002India D

Laboratory cultures of freshwater cyanobacterium (blue-green alga) Microcystis aeruginosa pCC 7806 was cv.luated for its hepatotoxic effects in rats. The lyophilized cell extract injected intraperitoneally at 1 and 2 LD50 (15.8 and 31.6 mg/kg, respectiv.ly) produced significant increase in liv.r-specific enzymes v.z. plasma alkaline phosphatase,γ-glutamyl transferase, lactate dehydrogenase with a concomitant decrease in hepatic glutamic pyruv.c transaminase. A corresponding increase in liv.r body weight index and histopathological changes in liv.r (degeneration of hepatocytes, congestion and hemorrhage etc.) are indicativ. of a dose and time dependent hepatotoxic nature of the algal extract

关键词： LDH Hepatotoxic and Histopathological Effects in rats Toxicity Ev.luation of in v.tro Cultures of Freshwater Cyanobacterium Microcystis aeruginosa

Heart failure in v.ry elderly population-a profile of heart failure in patients ov.r the age of eighty

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Journal of Geriatric Cardiology 2007年第1期4卷 20-24页

作者： Christopher v. Chien Dani Hackner Ernst r. Schwarz Div.sion of Cardiology and Comprehensiv. Transplant Center Department of Medicine Cedars Sinai Medical Center & University of California Los Angeles (UCLA) Los Angeles California USA

Objectiv. Heart failure is an epidemic in the elderly, but there is a striking lack of data in this clinically important patient population. We inv.stigated the demographics, cardiac performance, and medication management of a segment of the hospital popula- tion in at least their eighth decade of life. Methods We retrospectiv.ly rev.ewed 75 records of heart failure patients who were 80 years of age or older. records were rev.ewed for demographic information, presence or absence of diastolic dysfunction, ev.luation of ejection fraction, and medication usage including angiotensin-concerting enzyme (ACE) inhibitors, angiotensin receptor antagonists (ArBs), beta-adrenergic blockers, digoxin, and aldosterone antagonists. Assessment for contra-indications to ACE inhibitor or ArBs use was also performed to assess co-morbidities that limit treatment of heart failure. results The population of v.ry elderly with heart failure is heterogeneous. We found a higher proportion of females as well as higher rates of diastolic dysfunction in patients aged ≥ 90 years compared to patients between the ages of 80-89 years. Usage of ACE inhibitors, ArBs and beta-adrenergic blockers was strikingly low throughout the v.ry elderly population. While co-morbid conditions limited use of agents in many cases, there was a lack of explicit contra-indication in most patients not on an ACE inhibitor or an ArB. Conclusions Heart failure is not a single disease processes, but a continuum of disease processes that v.ry with age. The elderly with heart failure are an undertreated population, in part due to the multitude of co-morbidities that affect them. Further prospectiv. studies are needed to better understand the physiology and ideal treatment regiment in this growing population.

关键词： heart failure elderly octogenarians nonagenarians centenarians

Age-dependent peculiarities modulation of activ.ty of aldehyde scav.nger enzymes in mitochondria of rat thigh muscle during stress

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Frontiers in Biology 2016年第1期11卷 28-31页

作者： v.dim v. Dav.dov.Ev.enya r. Grabov.tskaya Amjad Hamdallah Chair of Biochemistry State Academican Lp.pav.ov.Medical Univ.rsity Ryazan 390026 Russia Chair of Medical Chemistry Kharkov.National Medical Univ.rsity Kharkov 61022 Ukraine Chair of Biochemistry EN. Karazin Kharkov.National Univ.rsity Kharkov 61077 Ukraine

The purpose of this study was a comparativ. inv.stigation of activ.ty of aldehyde scav.nger enzymes in mitochondrial fraction of a thigh muscle in intact and immobilized rats of different ages. It has been shown that 12- month-old （adult） rats hav. high basal lev.ls of aldehyde dehydrogenase, aldehyde reductase and glutathione transferase activ.ty in mitochondrial fraction of thigh muscle. Aldehyde dehydrogenase activ.ty increases during immobilization stress in adult rats. This change promote to enhance the effectiv.ness of utilization of carbonyl products of free radical oxidation in mitochondria of skeletal muscle of 12-month-old rats during stress. Immobilization of old and pubertal rats is accompanied by metabolic preconditions leading to accumulation of endogenous aldehydes in mitochondria, and, as a result, to the injury of muscular fibers and intensification of sarcopenia manifestations.

关键词： aldehydes mitochondria muscle immobilization stress aging

Experimental inv.stigation of the hot cracking mechanism in welds on the microscopic scale

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Frontiers of Materials Science 2011年第2期5卷 135-145页

作者： v. pLOSHIKHIN A. prIHODOv.KY A. ILIN neue Materialien Bayreuth GmbH Bayreuth Germany Integrativ. Simulation and Engineering of Materials and processes （ISEMp） University of Bremen 28359 Bremen Germany

The results Of the accurate experimental observ.tions on binary *** alloys are presented, which clearly demonstrate that the solidification cracking is a result of the accumulation of macroscopic tensile displacement in a microscopic intergranular r liquid film of segregates at the final stage of the weld metal solidification. The reconstructed mechanism of crack initiation prov.des a clear phenomenological interrelation between the cracking susceptibility, parameters of the welding process and properties of the base and filler material. The correspondent numerical model takes into account the effects of displacement accumulation as well as the influence ofthermodynamical and thermo-mechanical properties of the welded material. It is successfully applied for dev.lopment of technological means for elimination of the solidification cracking during welding of aluminium alloys AA6056, such as a multi-beam welding.

关键词： welding solidfication cracking numerical simulation