In recent years,the polyester industry has kept a stable development,and the consumption for PTA has been lifted up year by year.From 2001 to 2006,the growth rate of PTA consumption was around 20.7% averagely.Though i...In recent years,the polyester industry has kept a stable development,and the consumption for PTA has been lifted up year by year.From 2001 to 2006,the growth rate of PTA consumption was around 20.7% averagely.Though it began to be not as fast as it used to in recent a couple展开更多
This paper puts forward the concept of double semi-active vibration isolation systemutilizing the 'on-off' active damper and the 'on-off' active spring. Applying KBM Asympto-tic method, the vibration ...This paper puts forward the concept of double semi-active vibration isolation systemutilizing the 'on-off' active damper and the 'on-off' active spring. Applying KBM Asympto-tic method, the vibration of the system in case of weak semi-active control is studied. ln pcactice, there are two types of vibration isolation. One is to isolate the transmitting of the cyclicunbalanced force generated by the revolving machine to the surroundings. The other is to isolatethe transmitting of the vibration displacement of the surroundings to precise equipment. Deduc-ing the influence of the roadway unflatness on vehicles also belongs to this type. For the firsttype of isolation system, the damper always dissipates energy, and the total work done by the spring in a vibration cycle is zero. For the second type of isolation system, the work done by the damper sometimes is positive, and sometimes negative. The damper dissipates less energy. The work done by the spring in a vibration cycle isn't zero, and it is usually positive. ln thispaper, the vibration isolation is refered to the second type. .展开更多
Wilga M.Rivers points out that people get 45% information in life by listening while 30% by speaking, which proves that listening is a very important aspect of linguistic communication, and that listening is an import...Wilga M.Rivers points out that people get 45% information in life by listening while 30% by speaking, which proves that listening is a very important aspect of linguistic communication, and that listening is an important method for studying and mastering a language. As is known to all, language is an important tool for communication, while speaking and listening are the most original, important and basic parts of the language and are also important ways for the human to know the world and the inner minds of ourselves. Listening, speaking, reading and writing are so important that we put them in the first position. Listening ability refers not only to the direct listening skill, but also to the learners＇ linguistic ability, the cultural knowledge and the thinking ability. Improving listening ability is a complicated process; therefore, we should develop our skills, enrich our knowledge and improve our analyzing and inferring abilities.展开更多
Firms actively participate in the production of the global value chain(GVC),which is an important driving force for economic development.Using a difference-in-difference method,our research shows that industries that ...Firms actively participate in the production of the global value chain(GVC),which is an important driving force for economic development.Using a difference-in-difference method,our research shows that industries that are relatively more human-capital intensive experienced a larger GVC position upgrading after 2003 than they had in prior years.Second,mechanism analysis shows that human capital expansion increases firms’GVC position not only through an imported intermediate input effect but also through an innovation effect.Third,this study shows that increases in the college-educated labor force have a heterogeneous effect on a firm's GVC position across firms’various characteristics.Human capital expansion has the largest positive effect on state-owned firms relative to foreign and domestic private firms.Human capital expansion has also significantly improved the GVC position of firms located in China's eastern and central regions.The findings of this study indicate that it helps upgrading the GVC position of Chinese firms.展开更多
文摘In recent years,the polyester industry has kept a stable development,and the consumption for PTA has been lifted up year by year.From 2001 to 2006,the growth rate of PTA consumption was around 20.7% averagely.Though it began to be not as fast as it used to in recent a couple
文摘This paper puts forward the concept of double semi-active vibration isolation systemutilizing the 'on-off' active damper and the 'on-off' active spring. Applying KBM Asympto-tic method, the vibration of the system in case of weak semi-active control is studied. ln pcactice, there are two types of vibration isolation. One is to isolate the transmitting of the cyclicunbalanced force generated by the revolving machine to the surroundings. The other is to isolatethe transmitting of the vibration displacement of the surroundings to precise equipment. Deduc-ing the influence of the roadway unflatness on vehicles also belongs to this type. For the firsttype of isolation system, the damper always dissipates energy, and the total work done by the spring in a vibration cycle is zero. For the second type of isolation system, the work done by the damper sometimes is positive, and sometimes negative. The damper dissipates less energy. The work done by the spring in a vibration cycle isn't zero, and it is usually positive. ln thispaper, the vibration isolation is refered to the second type. .
文摘Wilga M.Rivers points out that people get 45% information in life by listening while 30% by speaking, which proves that listening is a very important aspect of linguistic communication, and that listening is an important method for studying and mastering a language. As is known to all, language is an important tool for communication, while speaking and listening are the most original, important and basic parts of the language and are also important ways for the human to know the world and the inner minds of ourselves. Listening, speaking, reading and writing are so important that we put them in the first position. Listening ability refers not only to the direct listening skill, but also to the learners＇ linguistic ability, the cultural knowledge and the thinking ability. Improving listening ability is a complicated process; therefore, we should develop our skills, enrich our knowledge and improve our analyzing and inferring abilities.
基金This research was financially supported by the Key Research Institutes of Humanities and Social of the Ministry of Education of China(No.17JJD790014)the Major Program of the National Social Science Foundation of China(Nos.13&ZD167 and 17ZDA114)。
文摘Firms actively participate in the production of the global value chain(GVC),which is an important driving force for economic development.Using a difference-in-difference method,our research shows that industries that are relatively more human-capital intensive experienced a larger GVC position upgrading after 2003 than they had in prior years.Second,mechanism analysis shows that human capital expansion increases firms’GVC position not only through an imported intermediate input effect but also through an innovation effect.Third,this study shows that increases in the college-educated labor force have a heterogeneous effect on a firm's GVC position across firms’various characteristics.Human capital expansion has the largest positive effect on state-owned firms relative to foreign and domestic private firms.Human capital expansion has also significantly improved the GVC position of firms located in China's eastern and central regions.The findings of this study indicate that it helps upgrading the GVC position of Chinese firms.
