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As an important part of die steels, hot-work die steels are mainly used to manufacture molds made of solid metal or high-temperature liquid metal from heating to recrystallization temperature. In view of the requirements for mechanical properties and service life for hot-work die steel, it is conducive to improve the thermal fatigue resistance, wear resistance, and oxidation resistance of hot work die steel. In this review, the main failure modes of hot-work die steel were analyzed. Four traditional methods of strengthening and toughening die steel were summarized, including optimizing alloying elements, electroslag remelting, increasing the forging ratio, and heat treatment process enhancement. A new nano-strengthening method was introduced that aimed to refine the microstructure of hot-work abrasive steel and improve its service performance by adding nanoparticles into molten steel to achieve uniform dispersion. This review provides an overview to improve the service performance and service life of hot work die steel. [ABSTRACT FROM AUTHOR]

Abstract In this paper, a projective splitting method for solving a class of generalized mixed variational inequalities is considered in Hilbert spaces. We investigate a general iterative algorithm, which consists of a splitting proximal point step followed by a suitable orthogonal projection onto a hyperplane. Moreover, in our splitting algorithm, we only use the individual resolvent mapping (I + μk∂f)-1 and never work directly with the operator T +∂f, where μk is a positive real number, T is a set-valued mapping and ∂f is the sub-differential of function f. We also prove the convergence of the algorithm for the case that T is a pseudomonotone set-valued mapping and f is a non-smooth convex function. 2000 Mathematics Subject Classification: 90C25; 49D45; 49D37.

In this article, some existence and uniqueness of solutions for a new class of global fractional-order projective dynamical system with delay and perturbation are proved by employing the Krasnoselskii fixed point theorem and the Banach fixed point theorem. Moreover, an approximating algorithm is also provided to find a solution of the global fractional-order projective dynamical system. Finally, an application to the idealized traveler information systems for day-to-day adjustments processes and a numerical example are given. [ABSTRACT FROM AUTHOR]

A new class of generalized dynamical systems involving generalized f -projection operators is introduced and studied in Banach spaces. By using the fixed-point theorem due to Nadler, the equilibrium points set of this class of generalized global dynamical systems is proved to be nonempty and closed under some suitable conditions. Moreover, the solutions set of the systems with set-valued perturbation is showed to be continuous with respect to the initial value. [ABSTRACT FROM AUTHOR]

Abstract: Xylitol production from xylose by a self-isolated furfural and 5-hydroxymethyl furfural assimilating Pichia guilliermondii was studied under oxygen limitation. An extremely low initial volumetric oxygen transfer coefficient (0.075 h−1) was found most favorable to the xylitol production with yield of 0.61 g g−1. Related enzymes activities were also investigated and discussed. [Copyright &y& Elsevier]