In the past two decades, the development of certain technologies, in particular Internet and mobile devices （tablet PCs, laptops, mobile telephones, etc.）, has brought about new habits of consuming audiovisual produ...In the past two decades, the development of certain technologies, in particular Internet and mobile devices （tablet PCs, laptops, mobile telephones, etc.）, has brought about new habits of consuming audiovisual products, predominantly among the youngest consumers. A new demand has arisen that has changed the channels of cinematographic exploitation and has allowed the growth of new business initiatives, such as new business models for distributing audiovisual content. The central aim of this paper is to analyse this new business model and to identify the main characteristics of the pioneering company in this sector, Netflix.展开更多
Recent and constant demands for greater power densities and smaller sizes of electronic systems have stimulated the growth of new designs of different passive heat transfer methods such as heat pipes. Particularly, OH...Recent and constant demands for greater power densities and smaller sizes of electronic systems have stimulated the growth of new designs of different passive heat transfer methods such as heat pipes. Particularly, OHPs （Oscillating Heat Pipes） are relatively novel devices, capable of removing high heat rates over long and short distances with not much temperature drop. This study concentrates on the design, building and assembling a test rig in order to analyse the flow pattern ofdeionised water through a 5 turns flat plate oscillating heat pipe under different heat inputs, which was made in the school of engineering and materials science of the Queen Mary University of London by two energy M.Sc. students. The filling ratio of the water is 40%. Furthermore an experimental study on the OHP thermal performance is carried out in order to examine the effects of different surface wet conditions： super hydrophilic, hydrophilic and cleaned brass. It is demonstrated the formation of liquid slugs and vapour plugs of the water along the channels. The experimental results showed that the hydrophilic surface tends to be more energy efficient. The heat transfer performance of the super-hydrophilic and hydrophilic is higher than brass by 5-12% and 15-20% respectively.展开更多
A sustainable production of electricity is essential for low carbon green growth in South Korea. Although wind energy is unlimited in potential, both intermittency and volatility should be tackled for smart grid integ...A sustainable production of electricity is essential for low carbon green growth in South Korea. Although wind energy is unlimited in potential, both intermittency and volatility should be tackled for smart grid integration in future. To cope with this, many works have been done for wind speed and power forecasting. It is shown that statistical techniques are useful for short-term forecasting of wind power. This paper presents a statistical wind speed forecasting. The wavelet decomposition is employed as a de-noising technique. An illustration will be given by real-world dataset. According to the result, the MAD （mean absolute deviation） is improved as much as 10%.展开更多
Cr_2Ge_2Te_6is an intrinsic ferromagnetic semiconductor with van der Waals type layered structure,thus represents a promising material for novel electronic and spintronic devices.Here we combine scanning tunneling mic...Cr_2Ge_2Te_6is an intrinsic ferromagnetic semiconductor with van der Waals type layered structure,thus represents a promising material for novel electronic and spintronic devices.Here we combine scanning tunneling microscopy and first-principles calculations to investigate the electronic structure of Cr_2Ge_2Te_6.Tunneling spectroscopy reveals a surprising large energy level shift and change of energy gap size across the ferromagnetic to paramagnetic phase transition,as well as a peculiar double-peak electronic state on the Cr-site defect.These features can be quantitatively explained by density functional theory calculations,which uncover a close relationship between the electronic structure and magnetic order.These findings shed important new lights on the microscopic electronic structure and origin of magnetic order in Cr_2Ge_2Te_6.展开更多
Extensively studied since the early nineties,cable-driven robots have attracted the growing interest of the industrial and scientific community due to their desirable and peculiar attributes.In particular,underconstra...Extensively studied since the early nineties,cable-driven robots have attracted the growing interest of the industrial and scientific community due to their desirable and peculiar attributes.In particular,underconstrained and planar cable robots can find application in several fields,and specifically,in the packaging industry.The planning of dynamically feasible trajectories(i.e.,trajectories along which cable slackness and excessive tensions are avoided) is particularly challenging when dealing with such a topology of cable robots,which rely on gravity to maintain their cables in tension.This paper,after stressing the current relevance of cable robots,presents an extension and a generalization of a model-based method developed to translate typical cable tension bilateral bounds into intuitive limits on the velocity and acceleration of the robot end effector along a prescribed path.Such a new formulation of the method is based on a parametric expression of cable tensions.The computed kinematic limits can then be incorporated into any trajectory planning algorithm.The method is developed with reference to a hybrid multi-body cable robot topology which can be functionally advantageous but worsen the problem of keeping feasible tensions in the cables both in static and dynamic conditions.The definition of statically feasible workspace is also introduced to identify the positions where static equilibrium can be maintained with feasible tensions.Finally,some aspects related to the practical implementation of the method are discussed.展开更多
文摘In the past two decades, the development of certain technologies, in particular Internet and mobile devices （tablet PCs, laptops, mobile telephones, etc.）, has brought about new habits of consuming audiovisual products, predominantly among the youngest consumers. A new demand has arisen that has changed the channels of cinematographic exploitation and has allowed the growth of new business initiatives, such as new business models for distributing audiovisual content. The central aim of this paper is to analyse this new business model and to identify the main characteristics of the pioneering company in this sector, Netflix.
文摘Recent and constant demands for greater power densities and smaller sizes of electronic systems have stimulated the growth of new designs of different passive heat transfer methods such as heat pipes. Particularly, OHPs （Oscillating Heat Pipes） are relatively novel devices, capable of removing high heat rates over long and short distances with not much temperature drop. This study concentrates on the design, building and assembling a test rig in order to analyse the flow pattern ofdeionised water through a 5 turns flat plate oscillating heat pipe under different heat inputs, which was made in the school of engineering and materials science of the Queen Mary University of London by two energy M.Sc. students. The filling ratio of the water is 40%. Furthermore an experimental study on the OHP thermal performance is carried out in order to examine the effects of different surface wet conditions： super hydrophilic, hydrophilic and cleaned brass. It is demonstrated the formation of liquid slugs and vapour plugs of the water along the channels. The experimental results showed that the hydrophilic surface tends to be more energy efficient. The heat transfer performance of the super-hydrophilic and hydrophilic is higher than brass by 5-12% and 15-20% respectively.
文摘A sustainable production of electricity is essential for low carbon green growth in South Korea. Although wind energy is unlimited in potential, both intermittency and volatility should be tackled for smart grid integration in future. To cope with this, many works have been done for wind speed and power forecasting. It is shown that statistical techniques are useful for short-term forecasting of wind power. This paper presents a statistical wind speed forecasting. The wavelet decomposition is employed as a de-noising technique. An illustration will be given by real-world dataset. According to the result, the MAD （mean absolute deviation） is improved as much as 10%.
基金supported by the Basic Science Center Project of NSFC(51788104)the MOST of China(2015CB921000)+6 种基金the support from Tsinghua University Initiative Scientific Research Program and NSFC(11774196)S.H.Z.is supported by the National Postdoctoral Program for Innovative Talents of China(BX201600091)the China Postdoctoral Science Foundation(2017M610858)the support of the National Key Research and Development Program(2016YFA0300404)NSFC Grant(11674326)the Joint Funds of NSFC and the Chinese Academy of Sciences’Large-Scale Scientific Facility(U1432139)supported in part by the Beijing Advanced Innovation Center for Future Chip(ICFC)
文摘Cr_2Ge_2Te_6is an intrinsic ferromagnetic semiconductor with van der Waals type layered structure,thus represents a promising material for novel electronic and spintronic devices.Here we combine scanning tunneling microscopy and first-principles calculations to investigate the electronic structure of Cr_2Ge_2Te_6.Tunneling spectroscopy reveals a surprising large energy level shift and change of energy gap size across the ferromagnetic to paramagnetic phase transition,as well as a peculiar double-peak electronic state on the Cr-site defect.These features can be quantitatively explained by density functional theory calculations,which uncover a close relationship between the electronic structure and magnetic order.These findings shed important new lights on the microscopic electronic structure and origin of magnetic order in Cr_2Ge_2Te_6.
基金supported by the Universita degli Studi di Padova under Grant No.CPDA088355/08
文摘Extensively studied since the early nineties,cable-driven robots have attracted the growing interest of the industrial and scientific community due to their desirable and peculiar attributes.In particular,underconstrained and planar cable robots can find application in several fields,and specifically,in the packaging industry.The planning of dynamically feasible trajectories(i.e.,trajectories along which cable slackness and excessive tensions are avoided) is particularly challenging when dealing with such a topology of cable robots,which rely on gravity to maintain their cables in tension.This paper,after stressing the current relevance of cable robots,presents an extension and a generalization of a model-based method developed to translate typical cable tension bilateral bounds into intuitive limits on the velocity and acceleration of the robot end effector along a prescribed path.Such a new formulation of the method is based on a parametric expression of cable tensions.The computed kinematic limits can then be incorporated into any trajectory planning algorithm.The method is developed with reference to a hybrid multi-body cable robot topology which can be functionally advantageous but worsen the problem of keeping feasible tensions in the cables both in static and dynamic conditions.The definition of statically feasible workspace is also introduced to identify the positions where static equilibrium can be maintained with feasible tensions.Finally,some aspects related to the practical implementation of the method are discussed.
