Study of Chinese Economic "Growth Drag" Caused by Land Resource in the Perspective of the Modified Two-Level CES Production Function

The purpose of the study is to measure the "growth drag" according to the characteristic of Chinese land resource.Romer model (2001) holds that every country is inevitably affected by the "growth drag" due to the limitation of land resource.So it's of profound strategic significance to measure the "growth drag" according to the character of Chinese land resource.Modified two-level CES production function was employed,and this paper modified the hypothesis of the model.The result indicates that the limitation of Chinese land resource casts shadow over the economic development of China,and the growth rate is 0.4618% lower than that without the limitation of land resource.Through implementing the land resource protection policy along with the technology improvement and the substitute effect of other factors to the land resource,China will keep a steady and balanced economic growth.

Improvement and optimization of preparation process of seedling-growing bowl tray made of paddy straw

A new type of rice seedling carrier named seedling-growing bowl tray made of paddy straw(SGBTMPS)was developed in China.Traditional preparation process for SGBTMPS is complex and difficult to operate.Hence,a new SGBTMPS preparation method has been developed by using straw powder as the main raw material.In this method,modified starch-based adhesive was replaced by the binder of thermosetting adhesive,and preparation constraints such as forming pressure,forming temperature,and dwell time were decreased.The effects of factors such as glue(modified starch-based adhesive),forming pressure,forming temperature and dwell time on SGBTMPS preparation were evaluated by single factor experiment.Orthogonal experiment and comprehensive weight analyses were adopted to optimize the parameters for SGBTMPS preparation.The results showed that optimized parameters were 125% glue and 1.2 kg mixed materials with the forming pressure,temperature,and dwell time of 30 MPa,140℃ and 330 seconds,respectively.Compared with traditional preparation process,the proportioning link,preparation link,and preparation time in the new preparation process were reduced by 66.7%,33.3%,and 17%,respectively;the pot-hole percentage and the expansion ratio were increased by 0.09% and 0.05%,respectively.This study indicated that the new preparation process for SGBTMPS was simpler and easier to operate and would provide a useful reference for further research and industrialization on SGBTMPS.