This paper constructs coefficients of the integral and the internal structure upgrading in the secondary and tertiary industries, selects per capita real gross domestic product as a threshold variable and build panel ...This paper constructs coefficients of the integral and the internal structure upgrading in the secondary and tertiary industries, selects per capita real gross domestic product as a threshold variable and build panel threshold model according to inter-provincial panel data of China from 1998 to 2016. Results indicated that population aging has a double threshold effect on the integral industrial structure upgrading, whose influence increases first and then decreases, significantly promoting the upgrading process. As for internal structure, population aging has no significant threshold effect on the upgrading in the secondary industry, but exerts a single negative threshold effect in the tertiary industry. When economic development is under the threshold, its negative impact is greater. Further analysis also suggests that regional differences exist significantly in the threshold effect of population aging on the industrial structure upgrading.展开更多
Wearable and portable electronic devices based on textile structure have been widely used owing to their wearability and comfortableness.However,yarn fineness and the comfort of the fabric cannot satisfy the requireme...Wearable and portable electronic devices based on textile structure have been widely used owing to their wearability and comfortableness.However,yarn fineness and the comfort of the fabric cannot satisfy the requirements of smart wearable devices.This work presents a novel strategy to prepare highly integrated PVDF/conductive nylon core-sheath structure piezoelectric yarns for wearable which is fabricated by combining electrospinning strategy with 2D braiding technology.The fineness of single yarns as well as strength are both improved significantly compared to previous works.The piezoelectric outputs of the yarn are still stable after 800 s fatigue test at a frequency of 4 Hz,and the cycle stability can maintain more than 3200 cycles.Furthermore,the piezoelectric yarns are further woven into piezoelectric plain fabric.According to the electrical performance,the length of the piezoelectric yarn and the thickness of the piezoelectric layer would both affect the output electrical performance.The yarn of the 10 cm in length and 600μm in fineness can produce an output voltage of 120 mV.Meanwhile,Both the piezoelectric yarn and the fabric could generate piezoelectric output signals through human movement,such as bending,walking.Therefore,the electrical and mechanical performance of the piezoelectric yarns prepared in our work could be improved significantly,and the comfortableness and durability performance of the piezoelectric fabric can satisfy most wearing requirements,which would provide some help in the field of piezoelectric wearable devices based on yarns and fabrics.展开更多
基金This study is supported by funds of National Natural Science Foundation of China’s project “China’s population aging process and labor productivity: inspection, forecasting and policy options”[Grant number: 71573093]National Natural Science Foundation of China’s project [Grant number:71573093].
文摘This paper constructs coefficients of the integral and the internal structure upgrading in the secondary and tertiary industries, selects per capita real gross domestic product as a threshold variable and build panel threshold model according to inter-provincial panel data of China from 1998 to 2016. Results indicated that population aging has a double threshold effect on the integral industrial structure upgrading, whose influence increases first and then decreases, significantly promoting the upgrading process. As for internal structure, population aging has no significant threshold effect on the upgrading in the secondary industry, but exerts a single negative threshold effect in the tertiary industry. When economic development is under the threshold, its negative impact is greater. Further analysis also suggests that regional differences exist significantly in the threshold effect of population aging on the industrial structure upgrading.
基金support from National Natural Science Foundation,China(Nos.52073224,51703179)National Key Research and Development Program of China(No.2019YFA0706801)+3 种基金Innovation Capacity Support Plan of Shaanxi,China(No.2020PT-043)Scientific and Technology Project for Overseas Students of Shaanxi,China(No.12)Scientific Research Program Funded by Shaanxi Provincial Education Department,China(Grant No:18JS041)Thousand Talents Program of Shaanxi Province.
文摘Wearable and portable electronic devices based on textile structure have been widely used owing to their wearability and comfortableness.However,yarn fineness and the comfort of the fabric cannot satisfy the requirements of smart wearable devices.This work presents a novel strategy to prepare highly integrated PVDF/conductive nylon core-sheath structure piezoelectric yarns for wearable which is fabricated by combining electrospinning strategy with 2D braiding technology.The fineness of single yarns as well as strength are both improved significantly compared to previous works.The piezoelectric outputs of the yarn are still stable after 800 s fatigue test at a frequency of 4 Hz,and the cycle stability can maintain more than 3200 cycles.Furthermore,the piezoelectric yarns are further woven into piezoelectric plain fabric.According to the electrical performance,the length of the piezoelectric yarn and the thickness of the piezoelectric layer would both affect the output electrical performance.The yarn of the 10 cm in length and 600μm in fineness can produce an output voltage of 120 mV.Meanwhile,Both the piezoelectric yarn and the fabric could generate piezoelectric output signals through human movement,such as bending,walking.Therefore,the electrical and mechanical performance of the piezoelectric yarns prepared in our work could be improved significantly,and the comfortableness and durability performance of the piezoelectric fabric can satisfy most wearing requirements,which would provide some help in the field of piezoelectric wearable devices based on yarns and fabrics.
