Abstract:     How to realize industrial transformation and improve total factor productivity is one of the major problems of high-quality economic development. Given that most manufacturing industries rely on service inputs, many scholars have begun to focus on how to improve the industrial productivity by promoting the service trade opening-up. Some researchers believe that service liberalization can improve enterprise productivity, but others believe that service liberalization can inhibit enterprise productivity. The main reasons for such beliefs are as follows: the first one is the lack of close links between the service and the industry, so is within the service; the second one is China′s technology-intensive service sector lags behind labor-intensive service sector; and the third one is the different service trade models have different effects on the efficiency of different types of industrial production. The existence of industrial heterogeneity means that the influence of the service trade opening-up to promote the improvement of industrial productivity also has different mechanisms. Once some channels are blocked, it may affect the technology promotion effect of the service. The crux of the problem is to find the channels which unblock the blocking mechanism. Some studies have found that there is a "Solow paradox" in R&D investment. The "Solow paradox" means that with the increase in R&D investment, the enterprise productivity will not rise, but continue to fall. The explanation for the "Solow paradox" of R&D investment mainly includes the moderation theory of R&D investment, the lag effect of R&D investment and the mismatch of R&D investment structure. The "Solow paradox" of R&D investment has become an entry point to study the influence of the service trade opening-up on the industrial productivity.
   Based on the panel data of twenty-three industries in China from the year of 2003 to 2014, this paper theoretically builds transmission and unblocking mechanism models of the service trade opening-up affecting the industrial green total factor productivity (GTFP), and uses both the mediating effect model and the moderating effect model for empirical analysis. Mediating effect model are often used to analyze the influence channels and action mechanisms of one variable on another variable. This is not possible with regression analysis, so more in-depth mechanism analysis can be performed. This article assumes that service trade opening affects industrial GTFP by affecting technological progress, and uses a mediating effect model to test the transmission mechanism of service industry opening through technology promotion effects to affect industrial GTFP. In addition, using the matching degree of R&D personnel and R&D expenditure as a variable to test whether the blocking conduction mechanism can be corrected by improving the matching degree of R&D investment.
    From the perspective of matching R&D investment, the paper tests the unblocking paths of service trade opening-up affecting the improvement of industrial GTFP, and compares the difference of unblocking effect in different industries. Specifically, on the one hand, the industrial GTFP is measured and compared with traditional total factor productivity. The result shows the industrial GTFP is lower than TFP, which means that there is still much room for industrial green transformation in China. On the other hand, from the three levels of all-industry, technology-intensive differences and differences in pollution levels, the mediating effects of the service trade opening-up through technology promotion effect on industrial GTFP are tested and compared. Then, by introducing the interaction term of service trade opening-up and R&D investment matching, the moderation effect model is used to test how to unblock the blocked technology promotion transmission mechanism, and compare the differences of the unblocking effects of different industrial types. 
    The main conclusions obtained in this paper are as follows: firstly, based on the all-industry level, the impact of service trade opening-up on industrial GTFP is not obvious, mainly because R&D investment has a "hiding effect", and the indirect path of service trade opening-up affecting industrial GTFP through technology promotion effect weakens the direct effect of the service trade opening-up on the industrial GTFP, resulting in the transmission mechanism of the technology promotion effect of the service trade opening-up on industrial GTFP is blocked. Secondly, in low-tech-intensive and high-tech-intensive industries, the mediating effect of service trade opening-up that improves industrial GTFP through technology promotion effect is not obvious, indicating that the mechanism of service trade opening-up improving industrial GTFP through technology effect is blocked. In low-tech-intensive industries, the blocked technology promotion transmission mechanism can be corrected by increasing the adaptation degree of R&D funding and R&D personnel investment; in high-tech-intensive industries, the effect of correcting the blocked technology promotion transmission mechanism by increasing the adaptation degree of R&D funding and R&D personnel investment is limited. Thirdly, in the clean industries, the mediating effect of the service trade opening-up promoting industrial GTFP is negative and significant, not significant in moderately polluting industries, and positively significant in highly polluting industries. This shows that in the two industries, the environmental regulations are relatively loose, the "innovation compensation effect" is not easy to play, and it is difficult to guide the R&D investment towards clean or green technology development. The transmission mechanism of the service trade opening-up promoting the industrial GTFP through technology effect is blocked and can be corrected by increasing the adaptation degree between R&D funding and R&D personnel. In highly polluting industries, due to strong environmental regulations, the mechanism of the service trade opening-up affecting industrial GTFP through technology promotion effect is relatively smooth.
    Based on the above conclusions, the policy recommendations of this article are as follows: Firstly, we must incorporate environmentally friendly features into the connotation of industrial transformation and upgrading, taking GTFP as the main goal of high-quality economic development, and pay special attention to green technological progress for the development. Secondly, the appropriate matching of R&D funding and R&D personnel can correct the blocked conduction mechanism to a certain extent, but in different industries, the effect of correction is also different. Therefore, it must be treated differently according to different industries.

Key words:  service trade opening-up, Solow paradox, R&D input match, green total factor productivity (GTFP)