1,721,057 research outputs found
A stress integration algorithm for plane stress elastoplasticity and its applications to explicit finite element analysis of sheet metal forming processes
No full textA stable stress integration algorithm of the elastoplastic constitutive equations for materials under a plane stress condition has been developed. In the algorithm, the trial stress obtained by elastic prediction is geometrically relaxed to the closest point on the yield surface in the principal stress plane. The direction of return-mapping is first obtained through the minimization problem using the Newton-Raphson method, and thereafter the plastic parameter is determined. As a model of yield criterion, Hill's quadratic normal anisotropic yield function has been adopted. The accuracy of the algorithm has been shown by iso-error maps for several materials. It has been revealed that errors are within 5% when the explicit time-integration method is adopted. In order to show the applicability of the algorithm, two kinds of sheet metal forming processes being able to represent various states of stress on the yield surface have been analyzed by FORMSYS-DE, the in-house explicit FEM code. The results of the simulations show good general coincidence with those of the experiments reported in the literature. (C) 1997 Elsevier Science Ltd
EFFECT OF DIE ANGLE AND PROCESS ROUTE ON THE TEXTURE EVOLUTION AND THE MICROSTRUCTURAL CHANGE OF COMMERCIALLY PURE ALUMINUM IN THE ECAE PROCESS
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Beam combination using stimulated Brillouin scattering for the ultimate high power-energy laser system operating at high repetition rate over 10 Hz for laser fusion driver
No full textAfter the laser was invented in 1960. a phase conjugation mirror has been respected to be the most fantastic one for the laser resonator composition because it can compensate any distortions of the laser beams occurred by the many inhomogenuities of the laser media and optical components. Among, the many phase col conjugation configurations, the stimulated Brillouin scattering phase conjugation mirror is the most simple one and many, researchers have tried to utilize it to develop high power/energy laser systems. For realizing a high energy/power laser system the thermal problem is the most difficult to solve. and some researchers suggested a beam combination technique to reduce the thermal load of the big laser media to many small sized ones. To;accomplish the beam combination using Stimulated Brillouin scattering phase conjugation mirrors (SBS-PCMs). it is necessary to lock/control the phases of the SBS-PCMs. And some researchers have developed several ways for it. but they can lock the phases of a limited number of beams overlapped at the foci less than 5, or lock the phases by back-seeding technique but it loses the phase conjugation characteristics. For realization of the laser fusion driver. it is necessary to combine more than 10 or 100 beams. And the authors have developed recently a new phase controlling/locking technique which is isolated and independent totally from other beams and it can be applied to an unlimited number of beams in principle. (c) 2006 The Optical Society of Japan.
Virus-induced diabetes mellitus. Glucose abnormalities produced in mice by thesix members of the Coxsackie B virus group
No full textBuilding an organizational decision support system for Korea Telecom: A process redesign approach
No full textOrganizational decision support systems (ODSSs) are a new type of decision support systems (DSSs) focusing on organization-wide issues rather than individual, group, or departmental issues. Because of its organization-wide scope, a typical ODSS cuts across organizational functions or hierarchical layers. Thus, seamless integration with organization's diverse IS applications running on heterogeneous platforms becomes a critical issue for building a successful ODSS. In this paper, we analyzed the Korea Telecom's (KT) Operations & Maintenance (O&M) division focusing on its investment strategies. We developed a conceptual framework through process redesign, which links O&M investment decisions to performance of its operational branches across the nation. To support the above framework, we also developed a prototype for the KTOM-ODSS with an EIS-like user-friendly interface. When a complete ODSS is implemented on top of various KT transaction processing systems, it will become a critical component of the O&M Integrated Decision Support Environment (IDSE). (C) 1997 Elsevier Science B.V
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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