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  • 11
    Electronic Resource
    Electronic Resource
    An anomalous voltage drop on the V-I characteristics of Bi(2223)/Ag sheathed tapes (1993)
    Springer
    Journal of materials science 12 (1993), S. 1676-1677 
    Details
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00418827
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  • 12
    Electronic Resource
    Electronic Resource
    X-ray photoelectron spectroscopy and corrosion studies of zinc phosphate coated on 7075-T6 aluminium alloy (1994)
    Springer
    Journal of materials science 29 (1994), S. 3653-3657 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Coated layers which formed on 7075-T6 aluminium alloy surfaces after treatment in zinc phosphate (ZPO) suspensions adjusted to different pH values (3.5, 5.0, 6.6, 10.5 and 13.0) were characterized by X-ray photoelectron spectroscopy (XPS). Comparative XPS tests were also made after the treated surfaces were exposed to a 3.5% NaCl solution for 5 h. The processes of coating from solution, oxidation, etching and bulk diffusion were all involved, although in different proportions, in the different treatments. The amounts of zinc and phosphorus in the uppermost layers were enhanced when the coating was at pH values of 5.0, 10.5 and 13.0, and in each case a mixed ZnO x -AlO x -ZPO structure was apparently formed. The coating prepared at pH=13.0 appeared to provide the best corrosion protection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00357331
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  • 13
    Electronic Resource
    Electronic Resource
    Why multi-load topology designs based on orthogonal microstructures are in general non-optimal (1993)
    Springer
    Structural and multidisciplinary optimization 6 (1993), S. 200-204 
    Details
    ISSN: 1615-1488
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract It is well established that for a compliance constraint, the optimal topology of perforated plates under plane stress tends to that for least-weight trusses (Michell structures) as the “volume fraction” (i.e. the ratio material volume/available volume) approaches zero. It is shown in this note that for two loading conditions the optimal bar orientations for Michell structures are in general non-orthogonal and hence the assumption of orthogonal microstructures in multi-load plate topology optimization must lead to erroneous results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01743514
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  • 14
    Electronic Resource
    Electronic Resource
    DCOC: An optimality criteria method for large systems Part II: Algorithm (1993)
    Springer
    Structural and multidisciplinary optimization 6 (1993), S. 250-262 
    Details
    ISSN: 1615-1488
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The theoretical basis for a new optimality criteria method (DCOC) was presented in Part I of this study (Zhou and Rozvany 1992). It was shown in that paper that a considerable gain in efficiency can be achieved by the proposed method, since the Lagrangian multipliers associated with stress constraints can be, in general, evaluated explicitly and hence the size of the dualtype problem is greatly reduced. The superior efficiency of the proposed method, for problems involving a large number of active stress constraints, was also demonstrated through simple numerical examples. In Part II, the computational algorithm of DCOC is presented in detail and several standard test examples are used for verifying the correctness and efficiency of the proposed method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01743384
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  • 15
    Electronic Resource
    Electronic Resource
    Continuum-type optimality criteria methods for large finite element systems with a displacement constraint. Part II (1990)
    Springer
    Structural and multidisciplinary optimization 2 (1990), S. 77-104 
    Details
    ISSN: 1615-1488
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In Part I of this study (Rozvanyet al. 1989), general aspects of iterative continuum-based optimality criteria (COC) methods were discussed and the proposed approach was applied to structural optimization problems with freely varying cross-sectional dimensions. In this paper, upper and lower limits on the cross-sectional dimensions, segmentation, allowance for the cost of supports and for selfweight, non-linear and nonseparable cost and stiffness functions and additional stress constraints are considered. The examples include beams with various geometrical properties and plates of variable thickness in plane stress. All results are compared with independently derived analytical or semi-analytical solutions and/or with solutions obtained by a mathematical programming (sequential quadratic programming, SQP) method. The number of elements in beam examples is up to one hundred thousand and in plane stress problems up to 3200 elements are used. Comparisons between computer time requirements for the COC and SQP methods are also presented. In addition, the problem of layout optimization is discussed briefly. The paper is intended to establish the power and versatility of the COC method. Notes. 1. Some less important symbols are defined where they first appear in the text. 2. Nondimensional variables are indicated by the sympbol ~.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01745456
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  • 16
    Electronic Resource
    Electronic Resource
    Exact least-weight truss layouts for rectangular domains with various support conditions (1993)
    Springer
    Structural and multidisciplinary optimization 6 (1993), S. 65-67 
    Details
    ISSN: 1615-1488
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A comprehensive review of both previously known and newly derived exact optimal layouts for rectangular domains with point loads and either line or point supports is given in this note.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01743176
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  • 17
    Electronic Resource
    Electronic Resource
    A note on truss design for stress and displacement constraints by optimality criteria methods (1991)
    Springer
    Structural and multidisciplinary optimization 3 (1991), S. 45-50 
    Details
    ISSN: 1615-1488
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract One of the difficulties with the optimization of large structural systems by optimality criteria (OC) methods, in which stress constraints are stated in terms of relative displacements, is the need to evaluate a large number of Lagrangians. An improved OC method, which does not require Lagrangians for stress constraints, is outlined in this note in the context of problems with stress constraints and a single displacement constraint. Whilst general formulae giving continuum-type optimality criteria for elastic systems are available (e.g. Rozvany 1989), the criteria for trusses are confirmed here by a simple derivation and verified on a ten-bar truss, for which the proposed technique and a dual programming method are shown to give a twelve-digit agreement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01743488
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  • 18
    Electronic Resource
    Electronic Resource
    Generalized shape optimization without homogenization (1992)
    Springer
    Structural and multidisciplinary optimization 4 (1992), S. 250-252 
    Details
    ISSN: 1615-1488
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Two types of solutions may be considered in generalized shape optimization. Absolute minimum weight solutions, which are rather unpractical, consist of solid, empty and porous regions. In more practical solutions of shape optimization, porous regions are suppressed and only solid and empty regions remain. This note discusses this second class of problems and shows that a solid, isotropic microstructure with an adjustable penalty for intermediate densities is efficient in generating optimal topologies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01742754
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  • 19
    Electronic Resource
    Electronic Resource
    DCOC: An optimality criteria method for large systems Part I: theory (1992)
    Springer
    Structural and multidisciplinary optimization 5 (1992), S. 12-25 
    Details
    ISSN: 1615-1488
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A highly efficient new method for the sizing optimization of large structural systems is introduced in this paper. The proposed technique uses new rigorous optimality criteria derived on the basis of the general methodology of the analytical school of structural optimization. The results represent a breakthrough in structural optimization in so far as the capability of OC and dual methods is increased by several orders of magnitude. This is because the Lagrange multipliers associated with the stress constraints are evaluated explicitly at the element level, and therefore, the size of the dual-type problem is determined only by the number of active displacement constraints which is usually small. The new optimaliy criteria method, termed DCOC, will be discussed in two parts. Part I gives the derivation of the relevant optimality criteria, the validity and efficiency of which are verified by simple test examples. A detailed description of the computational algorithm for structures subject to multiple displacement and stress constraints as well as several loading conditions is presented in Part II.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01744690
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  • 20
    Electronic Resource
    Electronic Resource
    The X-gene of human hepatitis B virus transactivates the c-jun and α-fetoprotein genes (1994)
    Springer
    Archives of virology 134 (1994), S. 369-378 
    Details
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The X-gene product of human hepatitis B virus is a transacting transcriptional factor which activates a variety of heterologous viral and host promoters/enhancers. We have found that the X-gene product can significantly transactivate the regulatory sequences located at the 5′-upstream of the c-jun oncogene when a reporter plasmid containing the sequences was co-transfected to HepG2 cells with an X-gene expression plasmid. The results of mutational analysis indicate that the X-gene activation requires the AP-1 sequence of the c-jun gene. Furthermore, we also found that the X-gene is capable of activating the 5′-upstream sequence of the α-fetoprotein gene. There are at least two elements that respond to the X-gene transactivation. One is located in the sequences between −5100 and −2900, and the other is at the C/EBP site. Therefore, the X-gene activates the c-jun and α-fetoprotein genes through different host factors, namely AP-1 and C/EBP, respectively. The results of c-jun activation by the X-gene strongly support the previous hypothesis that the X-gene may play a critical role in the development of hepatocellular carcinoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01310574
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