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Deformation‑Induced Strengthening Mechanism in a Newly Designed L‑40 Tool Steel Manufactured by Laser Powder Bed Fusion

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Acta Metallurgica Sinica(English Letters) 2023年第1期36卷 21-34页

作者： Yuan Tian Kanwal Chadha Clodualdo Aranas jr Voestalpine Additive Manufacturing Centre Ltd MississaugaON L5N 7Y3Canada Department of Mechanical Engineering University of New BrunswickFrederictonNB E3B 5A3Canada Planetary and Space Science Centre University of New BrunswickFrederictonNB E3B 5A3Canada

The microstructural and mechanical properties of a newly designed tool steel(L-40),specifcally designed to be employed in the laser powder bed fusion(LPBF)technique,were *** pool boundaries with submicron dendritic structures and about 14%retained austenite phase were evident after *** grain orientation after high cooling rate solidifcation is mostlyα∥building direction(BD).Then,the heat treatment converted the microstructure into a conventional martensitic phase,reduced the retained austenite to about 1.5%,and increasedα∥BD *** heat-treated sample exhibits higher tensile strength(1720±14 MPa)compared to the as-printed sample(1540±26 MPa)along the building direction,mainly due to hardening caused by a lower volume fraction of retained austenite phase and precipitation of *** a consequence of the strength-to-ductility trade-of,the heat-treated sample showed lower elongation(10%±2%)than that of the as-printed sample(18%±2%).It was observed that transformation-induced plasticity(TRIP)occurs in both the as-printed and heat-treated samples during tensile testing,which dynamically transforms the retained austenite into martensite,leading to improved *** minimum driving force to initiate the displacive phase transformation is about 6000 J/mol,which was achieved during tensile *** strength and ductility of LPBF-produced L-40 were compared with the other LPBF-produced tool steels in literature;the data indicate that heat-treated L-40 has an excellent combination of strength and ductility complemented with high printability.

关键词： Additive manufacturing Laser powder bed fusion L-40 tool steel Phase transformation

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The aggressive invasion of exotic reptiles in Florida with a focus on prominent species： A review

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Current Zoology 2011年第5期57卷 599-612页

作者： Richard ENGEMAN Elliott JACOBSON Michael L. AVERY Walter E. MESHAKA, jr. USDA/APHIS/Wildlife Services/National Wildlife Research Ctr 4101 LaPorte Ave. Fort Collins CO 80521-2154 USA College of Veterinary Medicine University of Florida Gainesville FL 32610 USA USDA/APHIS/Wildlife Services/National Wildlife Research Ctr 2820 East University Ave. Gainesville FL 32641 USA The State Museum of Pennsylvania 300 North Street Harrisburg Pennsylvania 17120 USA

Florida, along with Hawaii, has among the two worst invasive species problems in the USA, and the state is espe-cially susceptible to establishment by alien reptiles. Besides the large numbers of established non-native reptile species in Florida, many of these species present novel difficulties for management, or have other characteristics making effective management ex-tremely challenging. Moreover, initiation of management action requires more than recognition by experts that a potentially harmful species has become established. It also requires the political will along with concomitant resources and appropriate per-sonnel to develop effective methods and apply them. We review the situation in Florida, including assessment of risk for estab- lishment, and we use a subset of prominent species to illustrate in more detail the array of invasive reptile species circumstances in Florida, including routes of introduction, impacts, and potential and implemented management actions. These examples not only highlight the severity of the invasive reptile problems in the state, but they also show the diversity in resolve and response towards them and the motivating factors [Current Zoology 57 （5）： 599-612, 2011].

关键词： Argentine black and white tegus Biophysical ecology Burmese pythons Control Green and spiny-tailed iguanas,Invasive species Nile monitors Northern curlytail lizards

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Involuntary Unemployment： An Expository Note

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Frontiers of Economics in China-Selected Publications from Chinese Universities 2018年第1期13卷 83-92页

作者： Henry Y. Wan jr. Department of Economics Comell University Ithaca NY 14853 USA

This note is an effort to view the research program of Brecher and his co-workers to deploy tax incentives against involuntary unemployment in the broader context; on both the equity-efficiency trade-off in political ... 详细信息

关键词： involuntary unemployment efficiency wage wage rigidity

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Is Compositionality a Trivial Principle？

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Frontiers of Philosophy in China 2013年第1期8卷 140-155页

作者： Richard G. Heck, jr. Department of Philosophy Brown University Providence RI 02912 USA

Primarily a response to Paul Horwich＇s ＂Composition of Meanings,＂ this paper attempts to refute his claim that compositionality--roughly, the idea that the meaning of a sentence is determined by the meanings of its parts and how they are there combined--imposes no substantial constraints on semantic theory or on our conception of the meanings of words or sentences.

关键词： compositionality Horwich meaning semantics

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Real-time in situ detection and quantification of bacteria in the Arctic environment

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Journal of Innovative Optical Health Sciences 2014年第2期7卷 35-45页

作者： Linda Powers Walther R.Ellis jr. Christopher R.Lloyd Department of Electrical and Computer Engineering Department of Biomedical Engineering University of Arizona Tuc sonAZ 85721 Department of Biomedical Enginering University of ArizonaTucsonAz 85721 MicroBioSystems of Arizona 1665.E 18th St.Suite 204TucsonAZ 85719

At present,there are no methods that determine the total micro ial load on an abiotic substra tein real *** utility of such a capability ranges from sterilization and medical diagnostics tothe search for new microorganisms in the environment and study of their ecological *** the development of a hand held,fluorescence detection device and demonstrate its applicability to the field detection of Arctic bacteria,This technology is based on the early pioneering work of Britton Chance which elucidated the intrinsic fiuorescence of a number ofmetabolites and protein cofactors in cels,including reduced pyridine nucleotides,cytochromesand flavins.A PDA controls the device(fluorescence excitation and data collection)and processesthe multiwavelength signals to yield bacterial cell counts,including cstimates of ive cells,deadcells and *** existing methods for cell counting,this method requires no samplecontact or addition of *** use of this technology is demonstrated with in situmea surements of two sub-glacial microbial communities at sites in Palander and colonized surfacerocks in the Bockijord Volcanic Complex during AMASE 2008(Arctic Mars Analog Svalbard Expedition),The total bacterial load on the interrogated sample surfaces ranged from1o9 cells/cm^(2).

关键词： Intrinsic fuorescence microbial sensor optical detection amplitude modulation Svalbard Archipelago.

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Detection of Arterial Occlusions Using Viscoelastic Wave Propagation

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Advances in Applied Mathematics and Mechanics 2009年第1期1卷 1-28页

作者： H.T.Banks J.R.Samuels,jr. Center for Research in Scientific Computation North Carolina State UniversityCampus Box 8212RaleighNC 27695-8212USA

We consider the problem of detecting cardiac artery occlusions using stenosis driven viscoelastic(VE)waves propagated through biotissue to body surface *** investigate possible statistical model formulations(ordinary least squares(OLS),generalized least squares(GLS))and post analysis techniques(residual plots)to ascertain uncertainty in estimates as well as validity of the statistical models as part of a methodology for stenosis detection using viscoelastic waves.

关键词： Inverse problems viscoelastic models wave propagation in biotissue statistical models

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Preferential Bivalent Formation in Tetraploid Male of Pacific Oyster Crassostrea gigas Thunberg

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Journal of Ocean University of China 2014年第2期13卷 297-302页

作者： ZHANG Zhengrui WANG Xinglian ZHANG Quanqi Standish Allen jr. College of Marine Life Sciences Key Laboratory of Marine Genetics and Breeding of Ministry of EducationOcean University of China Aquaculture Genetics and Breeding Technology Center Virginia Institute of Marine ScienceCollege of William and Mary

Artificially induced tetraploid Pacific oyster, Crassostrea gigas Thunberg, produces more aneuploid gametes than nor- mal diploid one, although they showed a comparable fecundity to diploidy. The meiotic chromosome configuration of 3 tetraploid and 1 tetraploid/triploid mosaic males were analyzed through direct chromosome observation. A majority of metaphase I spermato- cytes contained both bivalents and quadrivalents. The chromosome configuration of these males was characterized by preferential formation of bivalents to quadrivalents. Bivalents appeared in all spermatocytes and consisted of 86% of all chromosome aggregates. In comparison, quadrivalents occurred in 91% spermatocytes and consisted of only 12.6% of all chromosome aggregates. The mean bivalent frequency per spermatocyte varied between 14.4 and 17.2; while that of quadrivalents varied between 2.2 and 2.7. Most quadrivalents were tandemly chained （58%） or circled （39%）. The total number of chromosome aggregates per spermatocyte ranged from 13 to 20 with an average of 17.6; while 18 （16 bivalents and 2 quadrivalents） was the most frequent. Univalents and trivalents appeared in very low frequency. Aneuploid （hypotetraploid） spermatocytes were observed in a low frequency. The chromosome con- figuration of in the mosaic individual was similar to that of tetraploid individuals. The percentage of triploid spermatocytes （2%） of the mosaic individual was significantly lower （2＂2 =30, P〈 0.01） than that of triploid cells （46%） in its somatic tissue.

关键词： tetraploid oyster meiosis bivalent quadrivalent reversion

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Dynamic Instability of Straight Bars Subjected to Impulsive Axial Loads Using the DEM

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Computer Modeling in Engineering & Sciences 2015年第2期104卷 87-104页

作者： Leticia Fleck Fadel Miguel Leandro Fleck Fadel Miguel Joao Kaminski jr. Department of Mechanical Engineering UFRGSPorto AlegreRSBrazil Department of Civil Engineering UFSCFlorianopolisSCBrazil Department of Structures and Civil Construction UFSMSanta MariaRSBrazil

Since the half of the XX century,attention was given to the instability of structures under parametric excitation,especially under periodic *** the other hand,the instability of bars subjected to axial loads of impulsive type has been little studied,in spite of the practical importance of the ***,in Engineering Design it is frequently supposed,without tests or additional verifications,that an axial load of short duration can exceed the Euler critical load of the bar without inducing damage in the *** this context,this paper proposes the use of the truss-like Discrete Element Method(DEM)for determining the dynamic response of elastic straight bars subjected to axial loads defined by pulses of short *** proposed approach allows the consideration of initial imperfections,as well as large displacements and other non-linear *** influence of the pulse duration and other effects in the response of the bar are also ***,the performance of the proposed methodology is verified in static and dynamic instability problems of homogeneous bars without geometrical imperfections,by comparing the DEM results with analytical solutions available in the *** that,the DEM is employed to analyze more complex cases,including bars with initial imperfections and non-homogeneous bars,in which material properties,as Young’s modulus and mass density,are assumed to be correlated Gaussian random *** proposed methodology has proven to be a useful and easy tool for analysis of dynamic instability of bars and could therefore be used by designers for estimating the dynamic buckling load.

关键词： Dynamic Instability Critical Buckling Load Discrete Element Method Impulsive Load Stochastic Fields Mesh Imperfections

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Deep Feature Learning for Intrinsic Signature Based Camera Discrimination

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Big Data Mining and Analytics 2022年第3期5卷 206-227页

作者： Chaity Banerjee Tharun Kumar Doppalapudi Eduardo Pasiliao jr. Tathagata Mukherjee Department of Idustrial&Systems Engineering University of Central FloridaOrlandoFL 32816USA Department of Computer Science University of Alabama in HuntsvilleHuntsvilleAL 35806USA Air Force Research Labs United States Air ForceEglin Air Force BaseShalimarFL 32579USA

In this paper we consider the problem of“end-to-end”digital camera identification by considering sequence of images obtained from the *** problem of digital camera identification is harder than the problem of identifying its analog counterpart since the process of analog to digital conversion smooths out the intrinsic noise in the analog *** it is known that identifying a digital camera is possible by analyzing the camera’s intrinsic sensor artifacts that are introduced into the images/videos during the process of photo/video *** is known that such methods are computationally intensive requiring expensive pre-processing *** this paper we propose an end-to-end deep feature learning framework for identifying cameras using images obtained from *** conduct experiments using three custom datasets:the first containing two cameras in an indoor environment where each camera may observe different scenes having no overlapping features,the second containing images from four cameras in an outdoor setting but where each camera observes scenes having overlapping features and the third containing images from two cameras observing the same checkerboard pattern in an indoor *** results show that it is possible to capture the intrinsic hardware signature of the cameras using deep feature representations in an end-to-end *** deep feature maps can in turn be used to disambiguate the cameras from each *** system is end-to-end,requires no complicated pre-processing steps and the trained model is computationally efficient during testing,paving a way to have near instantaneous decisions for the problem of digital camera identification in production *** we present comparisons against the current state-of-the-art in digital camera identification which clearly establishes the superiority of the end-to-end solution.

关键词： deep learning visual signatures camera identification convolutional neural networks deep feature learning

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Shape Selectivity of a Metallo Cavitand Host Allows Separation of n-Alkanes from Isooctane

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Chinese Journal of Chemistry 2021年第6期39卷 1498-1502页

作者： Yun-Hui Wan Faiz-Ur Rahman Julius Rebek jr. Yang Yu Center for Supramolecular Chemistry&Catalysis and Department of Chemistry College of ScienceShanghai University99 Shang-Da RoodShanghai 200444China Skaggs Institute for Chemical Biology and Department of Chemistry The Scripps Research Institute10550 North Torrey Pines Roadio JolloCA 92037USA

The use of a metallo cavitand for the selective sequestration of n-alkanes from their mixtures with isooctane is *** experiments and NMR spectroscopy are used to show the preference of a water-soluble cavitand host for guests that are hydro-phobic and have narrow or flat *** host showed selectivity for trans 1,4-dimethylcyclohexane over the *** sep-arations of n-alkanes from isooctane by gas/liquid adsorption and a liquid/liquid extraction are detailed.

关键词： Metallo cavitand Shape selectivity eceptor Alkane separation Host-guest system

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