This paper primarily focuses on two problems which aim at improving the results of the recent work of Yi S.S.(Yi S.S., Entry, licensing and research joint ventures, International Journal of Industrial Organization, ...This paper primarily focuses on two problems which aim at improving the results of the recent work of Yi S.S.(Yi S.S., Entry, licensing and research joint ventures, International Journal of Industrial Organization, 1999,17:1 24).Firstyly, two improper viewpoints are pointed out and rectified. Under his model, Yi argued that the potential entrants can be better off or worse off under the incumbent firm's strategic use of ex post licensing policy, but it is shown in this paper that the strategic licensing undoubtedly reduces the entrants'expected payoffs. Yi also noted wrongly that industry profit is a convex function of the number of firms in the product market by the Cournot oligopoly with a linear demand and constant marginal costs. However, in this paper it is demonstrated that industry profit in such a market is a concave convex function of the number of firms. Secondly, a thorough study of the optimal licensing policy for the incumbent is made on the basis of the correction of the second error. Necessary and sufficient conditions under which the incumbent will choose ex post licensing, ex ante licensing of one entrant or ex ante licensing of both extrants are given.展开更多
By using a pressure-based method and the finite volume method in the framework of the time dependent Reynolds-averaged Navier-Stokes equations, the authors studied the unsteady process of ventilated cavities generated...By using a pressure-based method and the finite volume method in the framework of the time dependent Reynolds-averaged Navier-Stokes equations, the authors studied the unsteady process of ventilated cavities generated forcing air through an orifice in a 2D hydrofoil without natural cavitation physically. The computation was carried out with the Volume Of Fluid （VOF） technique to track the gas-liquid two-phase interface. The results of simulation indicate that the ventilation rate is an important parameter in determining the morphology of cavity. There exists a critical value to convert sheet cavity into supereavity. A high ventilation rate can induce a two phase interface fluctuation and enable the ventilated eavitating flow to present a characteristic of periodicity.展开更多
文摘This paper primarily focuses on two problems which aim at improving the results of the recent work of Yi S.S.(Yi S.S., Entry, licensing and research joint ventures, International Journal of Industrial Organization, 1999,17:1 24).Firstyly, two improper viewpoints are pointed out and rectified. Under his model, Yi argued that the potential entrants can be better off or worse off under the incumbent firm's strategic use of ex post licensing policy, but it is shown in this paper that the strategic licensing undoubtedly reduces the entrants'expected payoffs. Yi also noted wrongly that industry profit is a convex function of the number of firms in the product market by the Cournot oligopoly with a linear demand and constant marginal costs. However, in this paper it is demonstrated that industry profit in such a market is a concave convex function of the number of firms. Secondly, a thorough study of the optimal licensing policy for the incumbent is made on the basis of the correction of the second error. Necessary and sufficient conditions under which the incumbent will choose ex post licensing, ex ante licensing of one entrant or ex ante licensing of both extrants are given.
文摘By using a pressure-based method and the finite volume method in the framework of the time dependent Reynolds-averaged Navier-Stokes equations, the authors studied the unsteady process of ventilated cavities generated forcing air through an orifice in a 2D hydrofoil without natural cavitation physically. The computation was carried out with the Volume Of Fluid （VOF） technique to track the gas-liquid two-phase interface. The results of simulation indicate that the ventilation rate is an important parameter in determining the morphology of cavity. There exists a critical value to convert sheet cavity into supereavity. A high ventilation rate can induce a two phase interface fluctuation and enable the ventilated eavitating flow to present a characteristic of periodicity.
