人工智能技术的发展,既提供了以自动化技术为主要特征的新动能,也提供了对人类脑力劳动进行分解、模拟和延伸的全新技术手段。工业机器人作为人工智能技术在生产领域的核心载体,既可以利用自动化技术成为工业生产的发动机,也可以通过生...人工智能技术的发展,既提供了以自动化技术为主要特征的新动能,也提供了对人类脑力劳动进行分解、模拟和延伸的全新技术手段。工业机器人作为人工智能技术在生产领域的核心载体,既可以利用自动化技术成为工业生产的发动机,也可以通过生产工具创新和生产知识创新实现工具机的价值。本文基于Becker and Murphy(1992)分工模型,刻画了工业机器人引发生产方式变革的演化路径:工业机器人首先以发动机的形式完成可自动化范围内的任务,进而以工具机的形式辅助劳动力实现非自动化范围内生产环节的分割重组,反向推动自动化范围内子任务的分工深化,最终实现整个任务区间生产方式的转变。经验研究表明:当工业机器人应用量达到一定规模时,增加工业机器人投入能够促进生产分割程度提升,行业研发投入的增加则会加速生产分割的进程。工业机器人应用对劳动生产率的影响过程与转变生产方式的演化路径高度吻合。本文的研究为政府引导工业企业“聚焦人工智能核心技术攻关,通过工业机器人应用加快推进生产分割”提供了理论与经验证据。展开更多
[Objective] The aim was to select the optimum conditions of xylitol Candida tropicalis conversion production. [Method] The effect of cell culture time,conversion time,conversion pH value,conversion initial sugar conce...[Objective] The aim was to select the optimum conditions of xylitol Candida tropicalis conversion production. [Method] The effect of cell culture time,conversion time,conversion pH value,conversion initial sugar concentration,speed and inoculation rate were determined respectively.[Result] Optimum fermentation conditions were obtained as follows:cell culture 16 h,conversion time 10 h,conversion pH value 5.5,conversion initial sugar concentration 20 g/L,conversion shaking speed 150 r/min,inoculation rate 10% (volume ratio). The yield of xylitol has increased to 90%. [Conclusion] This study had provided basis for the further study on xylitol.展开更多
Rural off-farm employment,rapid loss of agricultural land,and advanced technology popularization had led agricultural production in Chinese typical rural areas come at a critical transformation and upgrade stage.Based...Rural off-farm employment,rapid loss of agricultural land,and advanced technology popularization had led agricultural production in Chinese typical rural areas come at a critical transformation and upgrade stage.Based on sample survey data gathered from 401 households in Yucheng City,Shandong Province,this paper focuses on the characteristics and mechanism of agricultural transformation in typical rural areas of the eastern China.It was found that 74.3% of households surveyed kept at least one member engaging in off-farm employment,and 57.1% looked forward to expanding the operational scale of arable land,while just 13.7% had actually transferred their agricultural land.Since growing off-farm employment does not result in the collapse of traditional subsistence agriculture,therefore,agricultural production in Yucheng City is at an incomplete transformation phase from traditional small-holder farming to modern scale economy.It is caused by both macro environments and family characteristics,while urban-rural dual structure,imperfect rural development policy and agricultural technology popularization make peasant economy strengthen upon maintenance,and small-holder farming becomes peasant's natural response owing to pluriactivity,local off-farm employment,reverse elimination,etc.In order to achieve smooth agricultural transformation of typical rural areas in the eastern China,it needs to promote professional differentiation among peasants,under clear policies adopted by central government.Providing comprehensive services for agricultural production and improving production skills and knowledge of farmers who are still living in the countryside will effectively stimulate the process of agricultural transformation.展开更多
The conversion of solar energyinto electricity reveals a huge importance in the production of＂clean＂ energy, mainly when applied to decentralized production systems （micro-generation）. However, there is the need t...The conversion of solar energyinto electricity reveals a huge importance in the production of＂clean＂ energy, mainly when applied to decentralized production systems （micro-generation）. However, there is the need to develop and optimize these processes in order to turn it more sustainable in economic and technological scoops. The main purpose of this work is to study the solar energy conversion into electricity through photovoltaic cells, characterizing the process efficiencies. This study intends to evaluate the energetic and exergetic efficiencies defining them as indicators in the formulation ofa sustainability index. All the procedures are in a theoretical scope with an illustrative example in the end of this work.展开更多
The atomistic mechanism for direct conversion of graphite to diamond is a long-standing problem in condensed matter physics. The newly identified cold-compressed graphite phases of M, W and 0 carbon provide a crucial ...The atomistic mechanism for direct conversion of graphite to diamond is a long-standing problem in condensed matter physics. The newly identified cold-compressed graphite phases of M, W and 0 carbon provide a crucial link to understand the graphite-to- diamond phase transformation. We demonstrate by ab initio calculations that pressure has a dual role in lowering the conversion barrier and enhancing the production stability during the first-stage cold-compressed phase conversion of graphite toward the intermediate metastable M, W and 0 carbon phases. However, it has little effect on the relative enthalpy and high conversion barrier during the second-stage conversion process toward the diamond polytypes, showing a temperature dominated conversion process. These results may give explanation regarding the necessity of high pressure and high temperature during the graphite-to- diamond reaction.展开更多
The ability to generate stable and coherent short wavelength radiation is a great promise of the externally seeded free-electron laser. However, the fre- quency up-conversion efficiency is limited to a small number in...The ability to generate stable and coherent short wavelength radiation is a great promise of the externally seeded free-electron laser. However, the fre- quency up-conversion efficiency is limited to a small number in a single stage setup. In this paper, we propose a new scheme to produce coherent hard X-ray FEL with two- beam based two-stage echo-enabled harmonic generation configuration. Electron beams with quite different proper- ties are separately used in each stage and a monochromator is adopted to purify the radiation from first stage for seeding the second stage. Three-dimensional start-to-end simulations have been performed with realistic parameters to show the feasibility of the proposed scheme.展开更多
文摘人工智能技术的发展,既提供了以自动化技术为主要特征的新动能,也提供了对人类脑力劳动进行分解、模拟和延伸的全新技术手段。工业机器人作为人工智能技术在生产领域的核心载体,既可以利用自动化技术成为工业生产的发动机,也可以通过生产工具创新和生产知识创新实现工具机的价值。本文基于Becker and Murphy(1992)分工模型,刻画了工业机器人引发生产方式变革的演化路径:工业机器人首先以发动机的形式完成可自动化范围内的任务,进而以工具机的形式辅助劳动力实现非自动化范围内生产环节的分割重组,反向推动自动化范围内子任务的分工深化,最终实现整个任务区间生产方式的转变。经验研究表明:当工业机器人应用量达到一定规模时,增加工业机器人投入能够促进生产分割程度提升,行业研发投入的增加则会加速生产分割的进程。工业机器人应用对劳动生产率的影响过程与转变生产方式的演化路径高度吻合。本文的研究为政府引导工业企业“聚焦人工智能核心技术攻关,通过工业机器人应用加快推进生产分割”提供了理论与经验证据。
文摘[Objective] The aim was to select the optimum conditions of xylitol Candida tropicalis conversion production. [Method] The effect of cell culture time,conversion time,conversion pH value,conversion initial sugar concentration,speed and inoculation rate were determined respectively.[Result] Optimum fermentation conditions were obtained as follows:cell culture 16 h,conversion time 10 h,conversion pH value 5.5,conversion initial sugar concentration 20 g/L,conversion shaking speed 150 r/min,inoculation rate 10% (volume ratio). The yield of xylitol has increased to 90%. [Conclusion] This study had provided basis for the further study on xylitol.
基金Under the auspices of National Natural Science Foundation of China (No 40635029, 40771014)National Key Technologies R&D Program of China (No 2006BAB15B05)
文摘Rural off-farm employment,rapid loss of agricultural land,and advanced technology popularization had led agricultural production in Chinese typical rural areas come at a critical transformation and upgrade stage.Based on sample survey data gathered from 401 households in Yucheng City,Shandong Province,this paper focuses on the characteristics and mechanism of agricultural transformation in typical rural areas of the eastern China.It was found that 74.3% of households surveyed kept at least one member engaging in off-farm employment,and 57.1% looked forward to expanding the operational scale of arable land,while just 13.7% had actually transferred their agricultural land.Since growing off-farm employment does not result in the collapse of traditional subsistence agriculture,therefore,agricultural production in Yucheng City is at an incomplete transformation phase from traditional small-holder farming to modern scale economy.It is caused by both macro environments and family characteristics,while urban-rural dual structure,imperfect rural development policy and agricultural technology popularization make peasant economy strengthen upon maintenance,and small-holder farming becomes peasant's natural response owing to pluriactivity,local off-farm employment,reverse elimination,etc.In order to achieve smooth agricultural transformation of typical rural areas in the eastern China,it needs to promote professional differentiation among peasants,under clear policies adopted by central government.Providing comprehensive services for agricultural production and improving production skills and knowledge of farmers who are still living in the countryside will effectively stimulate the process of agricultural transformation.
文摘The conversion of solar energyinto electricity reveals a huge importance in the production of＂clean＂ energy, mainly when applied to decentralized production systems （micro-generation）. However, there is the need to develop and optimize these processes in order to turn it more sustainable in economic and technological scoops. The main purpose of this work is to study the solar energy conversion into electricity through photovoltaic cells, characterizing the process efficiencies. This study intends to evaluate the energetic and exergetic efficiencies defining them as indicators in the formulation ofa sustainability index. All the procedures are in a theoretical scope with an illustrative example in the end of this work.
基金supported by the National Natural Science Foundation of China(Grant No.11274356)the Ministry of Environmental Protection of China(Grant Nos.200909086 and 201109037)
文摘The atomistic mechanism for direct conversion of graphite to diamond is a long-standing problem in condensed matter physics. The newly identified cold-compressed graphite phases of M, W and 0 carbon provide a crucial link to understand the graphite-to- diamond phase transformation. We demonstrate by ab initio calculations that pressure has a dual role in lowering the conversion barrier and enhancing the production stability during the first-stage cold-compressed phase conversion of graphite toward the intermediate metastable M, W and 0 carbon phases. However, it has little effect on the relative enthalpy and high conversion barrier during the second-stage conversion process toward the diamond polytypes, showing a temperature dominated conversion process. These results may give explanation regarding the necessity of high pressure and high temperature during the graphite-to- diamond reaction.
基金supported by the National Development and Reform Commission([2013]2347)National Natural Science Foundation of China(11475250)the Shanghai Natural Science Foundation(13ZR1464700)
文摘The ability to generate stable and coherent short wavelength radiation is a great promise of the externally seeded free-electron laser. However, the fre- quency up-conversion efficiency is limited to a small number in a single stage setup. In this paper, we propose a new scheme to produce coherent hard X-ray FEL with two- beam based two-stage echo-enabled harmonic generation configuration. Electron beams with quite different proper- ties are separately used in each stage and a monochromator is adopted to purify the radiation from first stage for seeding the second stage. Three-dimensional start-to-end simulations have been performed with realistic parameters to show the feasibility of the proposed scheme.
