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Acoustic Measurements for Determination of the Materials Damping Using A Sound Source Localisation System

Acta Metallurgica Sinica(English Letters) 2013年第2期26卷 113-121页

作者： j. gken j. Swiostek H. Hurdelbrink U. Keil Faculty of Maritime Studies University of Applied Sciences Emden/Leer Bergmannstr. 36 26789 LeerGermany Stalomax TM Company of High-Precision Mechanics ul. Parkingowa 45 37450 Stalowa WolaPoland

Noise measurements are especially a problem when the obj.ct under investigation is largely dimensioned and can only be measured from the distance. To obtain information about the location of noise generation, a measurement technique which makes sound visible in order to introduce further specific technical measures is advantageous. The question is if the time dependence of the signal got from such a non touching and non destructive acoustic method has the potential to calculate the materials damping from. Using a small sound source localization system （Microflown^TM probe）, specimens of magnesium alloys with different grain sizes obtained by hydrostatic extrusion were investigated. It has been demonstrated that the fine grained microstructure led to a lower damping and its dependence on the strain was reduced. In this context, acoustic measurements by a sound source localisation system which makes materials characterization possible could be used as a quality tool to detect changes in highly stressed components. This approach allows to promote a selective substitution of conventional materials by more innovative ones. The offshore sector is considered to be a field of application： Wind turbines produce noise emission which stems mainly from turbulences at the tips of the rotor blades and vibrations of components inside the nacelle （e.9. gearbox, generator, ...）. If the vibration amplitudes are too high, microcracks of components can lead to failure over the long term. The monitoring of microstructural changes using a larger type of a sound source localisation system is considered as an innovative technical approach with respect to maintenance activities.

关键词： Magnesium Noise measurements MicroflownTM Damping

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INFLUENCE OF HEAT TREATMENT ON DAMPINg BEHAVIOUR OF THE MAgNESIUM WROUgHT ALLOY AZ61

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Acta Metallurgica Sinica(English Letters) 2007年第4期20卷 235-240页

作者： R. gonzález-Martínez j. gken D. Letzig j. Timmerberg K. Steinhoff K.U. Kainer Institute for Materials Research GKSS Research Center21502 GeesthachtGermany Institute of Maritime Studies University of Applied Sciences26789 LeerGermany Chair of Metal Forming Technology University of Kassel34125 KasselGermany

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of granato and Lücke.

关键词： magnesium AZ61 damping precipitation

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Apples to oranges:environmentally derived,dynamic regulation of serotonin neuron subpopulations in adulthood?

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Neural Regeneration Research 2025年第9期20卷 2596-2597页

作者： Christopher j.O’Connell Matthew j.Robson Department of genetics College of MedicineHarvard UniversityBostonMAUSA j.mes L.Winkle College of Pharmacy Division of Pharmaceutical SciencesUniversity of CincinnatiCincinnatiOHUSA Neuroscience graduate Program College of MedicineUniversity of CincinnatiCincinnatiOHUSA

Traumatic brain inj.ry(TBI)is a public health problem with an undue economic burden that impacts nearly every age,ethnic,and gender group across the globe(Capizzi et al.,2020).TBIs are often sustained during a dynamic range of exposures to energetic environmental forces and as such outcomes are typically heterogeneous regarding severity and pathology(Capizzi et al.,2020).

关键词： sustained orange dynamic

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New Finite Elements in Shear Stress Analysis of Saint Venant′s Torsional Loaded Beam Structures

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j.urnal of Materials Science & Technology 2003年第Z1期19卷 151-153页

作者： j. Brnic g. Turkalj Department of Engineering Mechanics Faculty of Engineering University of Rijeka Vukovarska 58 51000 Rijeka Croatia Department of Engineering Mechanics Faculty of Engineering University of Rijeka Vukovarska 58 51000 Rijeka Croatia

Recent engineering design as well as material processing on the optimization procedure are based and computeroriented. Finite element stress and sensitivity analysis are the most important things in such modern determinationof optimal solution. According to high computer capacity finite element continuum discretization and load applicationindependent of the coming fields become unlimited. This paper deals with the development of a new finite elementsgeneration used in shear stress analysis caused by ***′s torsional load and bending with shear. Their stiffnessmatrices and load vectors on the basis of their geometrical properties are derived. For j.stification of new finiteelements application some examples are presented.

关键词： New finite elements, Shear stress analysis, Optimal design

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gene therapy for spinal muscular atrophy:perspectives on the possibility of optimizing SMN1 delivery to correct all neurological and systemic perturbations

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Neural Regeneration Research 2025年第7期20卷 2011-2012页

作者： Sharon j.Brown Rafael j.Yáñez-Muñoz Heidi R.Fuller School of Pharmacy and Bioengineering Keele UniversityKeeleUK Wolfson Center for Inherited Neuromuscular Disease TORCH BuildingRJAH Orthopaedic HospitalOswestryUK *** Center of Gene and Cell TherapyDepartment of Biological SciencesSchool of Life Sciences and the EnvironmentRoyal Holloway University of LondonEghamUK

Spinal muscular atrophy(SMA)is a genetic condition that results in selective lower motor neuron loss with concomitant muscle weakness and *** genetic cause of SMA was understood in 1995 when loss or impairment of the survival motor neuron 1(SMN1)gene was identified as the main contributing factor(Lefebvre et al.,1995).This,in combination with the discovery that humans have a“back-up”gene,SMN2,which can produce low levels(approximately 10%)of the full-length functional SMN protein,has led to the generation of SMA-specific gene *** was traditionally classified according to age of symptom onset and developmental milestones achieved,with life expectancy and severity varying between ***,SMN2 copy number is used as a proxy for the prediction of disease severity,with higher SMN2 copy number typically being associated with reduced severity of SMA,although this relationship is not absolute:some individuals with low SMN2 copy number have less severe SMA phenotypes and vice ***,the etiology of SMA is further complicated by other factors,such as non-typical nucleotide variants and SMN2-independent modifiers of disease severity.

关键词： atrophy traditionally absolute

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MANY-SERVER QUEUES WITH CUSTOMER ABANDONMENT:A SURVEY OF DIFFUSION AND FLUID APPROXIMATIONS

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j.urnal of Systems Science and Systems Engineering 2012年第1期21卷 1-36页

作者： j. g. DAI Shuangchi HE H. Milton Stewart School of Industrial and Systems Engineering Georgia Institute of Technology Atlanta GA 30332 USA. Department of Industrial and Systems Engineering National University of Singapore Singapore 11757

The performance of a call center is sensitive to customer abandonment. In this survey paper, we focus on g/gI/n ＋ gI parallel-server queues that serve as a building block to model call center operations. Such a queue has a general arrival process （the g ）, independent and identically distributed （iid） service times with a general distribution （the first g1 ）, and iid patience times with a general distribution （the ＋gI）. Following the square-root safety staffing rule, this queue can be operated in the quality- and efficiency-driven （QED） regime, which is characterized by large customer volume, the waiting times being a fraction of the service times, only a small fraction of customers abandoning the system, and high server utilization. Operational efficiency is the central target in a system whose staffing costs dominate other expenses. If a moderate fraction of customer abandonment is allowed, such a system should be operated in an overloaded regime known as the efficiency-driven （ED） regime. We survey recent results on the many-server queues that are operated in the QED and ED regimes. These results include the performance insensitivity to patience time distributions and diffusion and fluid approximate models as practical tools for performance analysis.

关键词： Heavy traffic square-root safety staffing quality- and efficiency-driven regime efficiency-driven regime piecewise OU process

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Conservation laws for energy and momentum in curved spaces

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j.urnal of Zhej.ang University-Science A(Applied Physics & Engineering) 2007年第4期8卷 665-668页

作者： LóPEZ-BONILLA j. MORALES j. OVANDO g. Section of Postgraduate Studies and Research Superior School of Mechanical and Electrical EngineeringNational Polytechnic InstituteCP 07738Mexico Division of Basic Sciences and Engineering Autonomous Metropolitan UniversityCP 02200Mexico

In arbitrary Riemannian 4-spaces, continuity equations are constructed which could be interpreted as conservation laws for the energy and momentum of the gravitational field. Special attention is given to general relativity to obtain, of natural manner, the pseudotensors of Einstein, Landau-Lifshitz, Moeller, goldberg and Stachel, and also the conservation equations of Komar, Trautman, DuPlessis and Moss.

关键词： Noether theorem Lagrangians in curved spaces Energy and momentum in Riemannian spaces Rund-Lovelock identities

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Lethal neuroendocrine carcinoma in ulcerative colitis

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World j.urnal of gastroenterology 2009年第46期15卷 5882-5883页

作者： Hugh j.Freeman ken Berean Department of Medicine(gastroenterology) University of British ColumbiaVancouver Department of Pathology University of British ColumbiaVancouver

A 48-year old male with longstanding and extensive pancolitis developed a high grade and rapidly lethal malignant lesion in the ascending colon characterized by a neuroendocrine *** biopsies obtained from multiple sites in the colon during endoscopic surveillance were reported to show only inflammatory changes without *** operator-dependent,repeated endoscopic studies may have limitations during surveillance programs because the biological behavior of some colonic neoplastic lesions may have a rapid and very aggressive clinical course.

关键词： Colorectal cancer, Neuroendocrine carcinoma Ulcerative colitis Surveillance colonoscopy Dysplasia

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The Friction and Wear Properties of CrN, graphit-iC and Dymon-iC Coatings in Air and under Oil-lubrication.

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材料热处理学报 2004年第05B期25卷 858-861页

作者： j. Stallard D.g Teer Teer Coatings Ltd Droitwich WorcestershireU.KTeer Coatings Ltd Droitwich WorcestershireU.K.

Hard ceramic coatings such as TiN and CrN are very successful and are widely used in improving the performance of cutting and forming tools, but they are less successful in providing protection for general machine components, such as gears and engine parts. The development of low-friction wear resistant coatings that can run dry or in a minimum amount of oil is becoming increasingly important to this industry. Two recently developed carbon-based coatings graphit-iC? and Dymon-iC, which are shown to exhibit very high sliding wear resistance and low friction in dry conditions, are compared to a CrN coating under oil lubricated conditions. Long term pin-on-disc tests using a chrome steel counterface ball were carried out on coated HSS test samples. All the coatings performed well at very high applied contact pressures, exceeding 1.5 gPa, but the graphit-iC? and Dymon-iC coatings also exhibited the desirable characteristic of protecting the counterface material. Reasons for this behaviour are discussed.

关键词： DLC 润滑油摩擦性能磨损性能涂层

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The nature of the companion of PSR j.719-1438: a white dwarf or an exotic obj.ct?

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Research in Astronomy and Astrophysics 2012年第7期12卷 813-816页

作者： j. E. Horvath Instituto de Astronomia Geofísica e Ciências Atmosfricas - Universidade de So Paulo

We raise the possibility that the very dense, compact companion of PSR j.719-1438, which has a j.piter-like mass, is an exotic quark obj.ct rather than a light helium or carbon white dwarf. The exotic hypothesis naturally explains some of the observed features, and provides quite strong predictions for this system, to be confirmed or refuted in feasible future studies.

关键词： binary pulsars -- exotic matter-- pulsars: individual (PSR j.719-1438)

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