The University of Science and Technology Beijing , formerly known as Beijing Steel and Iron Institute before 1988, is a national key university in Beijing, China. USTB's metallurgy and materials science programmes are highly regarded in China. Wikipedia.
Cao G.,University of Science and Technology Beijing
Recent progress of simulations/modeling at the atomic level has led to a better understanding of the mechanical behaviors of graphene, which include the linear elastic modulus E, the nonlinear elastic modulus D, the Poisson's ratio v, the intrinsic strength σint and the corresponding strain εint as well as the ultimate strain εmax (the fracture strain beyond which the graphene lattice will be unstable). Due to the two-dimensional geometric characteristic, the in-plane tensile response and the free-standing indentation response of graphene are the focal points in this review. The studies are based on multiscale levels: including quantum mechanical and classical molecular dynamics simulations, and parallel continuum models. The numerical studies offer useful links between scientific research with engineering application, which may help to fulfill graphene potential applications such as nano sensors, nanotransistors, and other nanodevices. © 2014 by the authors; licensee MDPI, Basel, Switzerland. Source
Wang W.,University of Science and Technology Beijing
Reliability Engineering and System Safety
Industrial plant maintenance is an area which has enormous potential to be improved. It is also an area attracted significant attention from mathematical modellers because of the random phenomenon of plant failures. This paper reviews the recent advances in delay-time-based maintenance modelling, which is one of the mathematical techniques for optimising inspection planning and related problems. The delay-time is a concept that divides a plant failure process into two stages: from new until the point of an identifiable defect, and then from this point to failure. The first stage is called the normal working stage and the second stage is called the failure delay-time stage. If the distributions of the two stages can be quantified, the relationship between the number of failures and the inspection interval can be readily established. This can then be used for optimizing the inspection interval and other related decision variables. In this review, we pay particular attention to new methodological developments and industrial applications of the delay-time-based models over the last few decades. The use of the delay-time concept and modeling techniques in other areas rather than in maintenance is also reviewed. Future research directions are also highlighted. © 2012 Elsevier Ltd. Source
Wu X.Z.,University of Science and Technology Beijing
An important issue regarding the use of probabilistic predictions for complex engineering systems is characterising the dependence structure among its correlated performance functions, which are driven by dependent or independent basic random variables. The interrelationship of these performance functions can be attributed to the same random variables and the cross correlation among the input parameters. An assessment of joint failure probability for an engineering system is proposed, which is associated with the correlated performance functions using a copula-based method by conveying the dependence structure of the performance functions. The method is demonstrated with four simple engineering problems, i.e., (a) bivariate distribution in which two predetermined performance functions are associated with each other; (b) pile bearing capacity in which the performance functions are related with the soil internal friction and the compressive strength of a concrete pile; (c) pipe flow in which the performance function of three pipes in a sewer system is assessed with six independent random variables; and (d) retaining wall in which the failure criteria for defining the performance functions include overturning failure about the toe point, sliding failure along the base, and bearing capacity instability considering uncertain soil properties. The computational efficiency is evaluated using the results based on the conventional bounding methods. The joint failure probability expressed by copulas provides a means to obtain the joint probabilities of multiple failure modes, which pave the way for an objective description of the overall failure probability of a practical engineering problem. © 2014 Elsevier Ltd. Source
University of Science and Technology Beijing | Date: 2013-01-17
The invention belongs to the field of recycling of resources, in particular to a method for waste rare earth luminescent material by dual hydrochloric acid. First hydrochloric acid was used to dissolve the red phosphor powder (Y
Chinese Academy of Sciences, Ukrainian Academy of Sciences, University of Science, Technology Beijing and Beijing Huarong Tianchuang Superconduct Technology Development Co. | Date: 2014-03-03
A measuring whispering-gallery-mode resonator, comprising: a dielectric resonating body with a rotation axis; a superconducting sample under test, which is mounted to the resonating body; a coupling unit for coupling a measuring waveguide with the resonating body, wherein one side of the resonating body connected with the coupling unit is provided with a first endplate, wherein m coupling holes penetrate through the first endplate, and centers of the m coupling holes are arranged to be evenly spaced along a circle whose center is on the rotation axis; the coupling unit has a feeder line which is a coaxial waveguide, wherein an axis of the coaxial waveguide coincides with the rotation axis, and one end surface of the coaxial waveguide, which is perpendicular to the rotation axis, abuts to the first endplate; and the axial index of operated whispering gallery mode in the resonator is an integer multiple of the number m of the coupling holes.