数学建模及数学建模竞赛的组织与培训

论述了数学模型的一般概念,讨论了数学模型的分类及数学建模的步骤和方法。结合辅导数学建模竞赛的经验,研究了数学建模竞赛的组织与培训问题。     

The mathematical modeling revolution in extractive metallurgy

A brief review is presented of the current state of extractive metallurgy, and it is shown that it is still a significant part of the national economy. Then a definition is given of mathematical models, and the general philosophy of modeling is discussed, together with the cost of models, hardware, and software options. Several illustrative examples are given, drawn from aluminum electrolysis, flash smelting, tundish operations, and plasma systems. The paper is concluded with the future modeling tasks facing us; these include the more widespread applications of models to represent both existing and new processing operations. It is stressed that models can play a major role in developing a holistic approach to metals and materials processing, where the primary extraction and refining operations are combined with the final processing steps.     

The mathematical modeling revolution in extractive metallurgy

A brief review is presented of the current state of extractive metallurgy, and it is shown that it is still a significant part of the national economy. Then a definition is given of mathematical models, and the general philosophy of modeling is discussed, together with the cost of models, hardware, and software options. Several illustrative examples are given, drawn from aluminum electrolysis, flash smelting, tundish operations, and plasma systems. The paper is concluded with the future modeling tasks facing us; these include the more widespread applications of models to represent both existing and new processing operations. It is stressed that models can play a major role in developing a holistic approach to metals and materials processing, where the primary extraction and refining operations are combined with the final processing steps.     

Current issues in nerve repair

Although accepted surgical techniques for peripheral nerve repair remain largely unchanged over the past three decades, much progress has been made toward understanding the mechanisms involved in nerve regeneration, and consequently toward providing adjunctive measures to enhance this regenerative process. We present a comprehensive review of the significant advances made in several aspects of nerve repair over the past decade, and particularly the past few years, and provide a few examples of facial nerve repair using the standard neurorrhaphy techniques recommended today. Several conclusions were drawn after thorough review of the literature. Early repair of injured nerves is preferred, and there appears to be no benefit to waiting for 3 weeks. Severed nerves should be repaired with monofilament 9-0 nylon suture placed in epineurial fashion. Fibrin glue confers no benefit in reattaching injured nerves. Likewise, theoretical advantages of laser neurorrhaphy have not resulted in improved nerve regeneration. Finally, trophic factors, such as apolipoproteins and nerve growth factor, and tubulization both appear to offer promise for future experimental and clinical progress in nerve repair. However, further work must be done to prove their efficacy.     

Experimental and mathematical modeling of metal spray forming process

The metal spray forming process was examined using mathematical simulation and verified through the prototyping evaluation at Baosteel’s test and development facilities.The mathematical model comprised of four sections,including jet gas flow in the deposition chamber;single droplet behavior along its trajectory path;probability and statistical analysis of droplet mass behavior,and forecast of the shape and temperature distribution of the billet during the spray forming process.     

The mathematical and physical modeling of turbulent recirculating flows

A physical model has been constructed to represent turbulent recirculating flows that occur in argon-stirred ladles. By using a mechanically driven circulating system including a moving tube it was possible to generate flow fields such that all the boundary conditions could be defined unambiguously. The velocity fields developed in the system and the spatial distribution of the turbulent kinetic energy were measured experimentally using a laserdoppler anemometer. The experimental measurements were found to be in good agreement with predictions based on theK-W model for turbulent recirculating flows, provided appropriate wall functions were used. A simplified model was also described in the paper, for representing the transient decay of turbulence in teemed systems or in bubble stirred vessels after the agitation had been terminated. This model, which in essence involved the use of a simple algebraic relationship, gave semiquantitative agreement with measurements. R.METZ, formerly Graduate Student Department of Chemical Engineering, State University of New York at Buffalo,     

On mathematical modeling of dermal and transdermal drug delivery

This paper deals with two extensions of diffusion models for the drug delivery process into human skin in order to give a more realistic approach. As one extension several penetrating substances formulated within a vehicle are considered for modeling the case of an applied drug and some penetration modifiers (enhancers and reducers, respectively). A coupling via concentration-dependent diffusivities between the diffusion equations of the involved substances is used to model the dependencies between them. Furthermore, a moving boundary problem for the diffusion equation of the drug delivery process is developed to describe the time-dependent maximum penetration depth of each penetrant marked by a movingboundary. On this basis a model is developed that can predict both the concentration profile and the position of the penetration boundary depending on time. Both concepts are described on a two-dimensional multilayered domain representing a cross section through human skin. The model equations are solved by exploiting a suitable numerical discretization method.     

Current trends and issues in adaptation-level theory.

"Adaptation levels appear as neutral or indifferent zones in bipolar responses… . Adaptation levels are revealed in all forms of behavior whether they are sensory, motor, or cognitive verbal in nature… . We have found that the weighted log mean definition of AL [Adaptation Level] is the best approximation to the neutral or indifferent region for sensory magnitudes." Studies indicating current trends that bear on fundamental issues in AL theory are considered under the following headings: Anchoring Effects of Subliminal Stimuli; Residual Effects of Anchors in Memory and Recall; Series Effects with an Absolute, Extraexperimentally Anchored Language; Neutral Zones in Unexpected Places; Assimilation and Contrast in Sensory and Social-judgmental Processes; The Methodological Importance for Social Psychology of Studies Leading to Functional Relations Between Variables; and An Adaptation-level for Reinforcement and Performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Current status and prominent issues in sport psychology interventions

The prospect of human psycho-behavioral change has fueled the development and growth of applied sport psychology and psychological intervention with athletes. The purpose of this review is to examine the current status of sport psychology interventions and identify issues related to psychological intervention in sport. The development of sport psychology in North America is overviewed and issues arising from the emergence of applied sport psychology are identified. Sport psychology intervention research is reviewed and it is concluded that the effectiveness of sport psychology interventions is supported in the literature. Problems in intervention research are identified and future directions for sport psychology are suggested. These suggestions include a science-practice integration, the use of idiographic assessment methods, the identification and control of moderator variables, and the contextualization of interventions within the unique environment of sport.     

Current issues in the diagnosis and therapy of diabetic nephropathy

Significant increases in serum levels of IgE have often been observed in allogeneic bone marrow transplantation patients and have generally been thought to be diagnostic of graft-versus-host disease (GVHD), rather than an agent involved in the pathogenesis of the disease. Experimental murine GVHD models have also indicated associations of hyper-IgE activity, yet the role of IgE in GVHD pathogenesis has never been tested directly. In the current study, we have tried to address this issue by using recently developed peptide analog antagonists for the interaction of IgE with the Fc epsilon RI receptor, which is necessary for triggering mast cells and other cell types when cross-linked by antigens. A synthetic cyclized 13-amino acid peptide was previously designed from the modeled C-C' loop region of the Fc epsilon RI alpha-chain and was found to act as a competitive inhibitor of IgE-Fc epsilon RI alpha binding. The peptide was generated in two forms, a cyclic L-(L-IgEtide) and retro D-amino acid composition (rDIgEtide), the latter to increase resistance to protease degradation for in vivo applications. These two inhibitor peptides were then used to test the hypothesis that IgE could be involved in the pathogenesis of acute GVHD, in the B10.D2-->DBA/2 (900 cGy) strain combination, with GVHD directed to minor histocompatibility antigens. Both peptides demonstrated significant inhibition of the development of lethal GVHD, supporting the involvement of IgE at some level of disease pathogenesis.     

Current development in quantitative phase-field modeling of solidification

The quantitative phase-field simulations were reviewed on the processes of solidification of pure metals and alloys.The quantitative phase-field equations were treated in a diffuse thin-interface limit, which enabled the quantitative links between interface dynamics and model parameters in the quasi-equilibrium simula-tions.As a result, the quantitative modeling is more effective in dealing with microstructural pattern for-mation in the large scale simulations without any spurious kinetic effects.The development of the quanti-tative phase-field models in modeling the formation of microstructures such as dendritic structures, eutec-tic lamellas, seaweed morphologies, and grain boundaries in different solidified conditions was also re-viewed with the purpose of guiding to find the new prospect of applications in the quantitative phase-field simulations.     

A Study on the mathematical modeling of turbulent recirculating flows in gas-stirred ladles

Computed results are presented describing the velocity field and the map of the turbulent kinetic energy in a water model of an argon-stirred ladle. The theoretical predictions agree well with the measurements, when an experimentally determined void fraction distribution is used in computing the body force driving the flow. The agreement is somewhat less satisfactory, particularly regarding the maps of the turbulent kinetic energy, when the no-slip or the drift flux models are used to predict the void fraction of the gas.