Abstract:

International technology diffusion is an important way to improve a country's technological innovation capability. However， under the current situation of the resurgence of international trade protectionism， the effect of technology diffusion obtained by enterprises through international trade is weakening. Under this new international situation， how to formulate coping strategies to improve its technological level and achieve long-term economic and social development is an urgent problem faced by all countries， especially developing countries. In view of this， Nash equilibrium， variational inequality and Lagrange dual theory are used to establish a multi-stage international supply chain network equilibrium model to analyze the impact of raising tariffs and limiting technology diffusion on technological progress， the interests of supply chain members and the economic and environmental benefits of the whole society. In the model， different values of the tax factor K_tmn are set to distinguish the VAT on domestic sales from the tariff on foreign sales. It should be noted that the taxes in this article are ad valorem taxes. By setting different technology diffusion influence factors e_tim， the government can control technology diffusion differently. In addition， the government subsidizes the technology investment of manufacturers， and the amount of subsidy is a certain proportion of the technology investment. Combined with numerical examples and network equilibrium variational inequality conditions， the projection contraction algorithm is used to design the program and run it through Matlab software. The following conclusions are drawn from the analysis of numerical results： Under the condition that the costs of enterprises in the two countries are symmetrical and the two countries take equal measures to limit the technology diffusion， increasing the rate of tariff growth will expand the production and consumption of local products， increase the consumer surplus， but reduce corporate profits and social welfare and the technical level of products. Appropriate technical subsidies are beneficial to consumers， enterprises and the whole society， and are conducive to the improvement of technical level. Restricting technology diffusion is not good for consumers， enterprises and society as a whole， nor is it conducive to the development of technology level. Therefore， countries or regions with similar economic strength and scientific and technological level should strive to build free trade zones to achieve mutual benefit and win-win results brought about by free trade and technical cooperation.

Key words: international supply chain network, tariff, trade protectionism, technology investment, variational inequality