Ultra-large plate forgings are foundation of heavy machinery,but many parts of the type cannot be made by conventional technologies due to the characters of extreme manufacturing in terms of size and quality requireme...Ultra-large plate forgings are foundation of heavy machinery,but many parts of the type cannot be made by conventional technologies due to the characters of extreme manufacturing in terms of size and quality requirements.This paper introduced a systematically method called cylinder unfolding method(CUM)for producing large plate forgings,by using a serial of operations including“splitting”,“unfolding”,and“flattening”of a thick cylinder obtained from saddle forging.The technological route of CUM was presented in detail with an example of plate forging with the horizontal sizes of 6100 mm and thickness of 300 mm.The deformation features of saddle forging for fabricating transitional cylinders were analyzed,and then the subsequent handling steps including splitting,unfolding and flattening of the cylinder,as well as the auxiliary processing,were addressed.The practice proved that CUM can provide an efficient way for manufacturing ultra-large plate forgings and meet the strict requirements in geometry and mechanical performance,without highly increasing the investments of forming equipment and tooling.展开更多
Industrialization has been a dream for the Chinese nation since modern history and a goal of the Communist Party of China(CPC).Ever since its founding in 1921,the CPC has been exploring a path for China’s industrial ...Industrialization has been a dream for the Chinese nation since modern history and a goal of the Communist Party of China(CPC).Ever since its founding in 1921,the CPC has been exploring a path for China’s industrial development based on socialism as the political and institutional premise.Since the founding of the People’s Republic of China in 1949,the Chinese people have established a socialist system under the CPC’s leadership and carried out industrial development for over seven decades in the world’s most populous country,blazing a new trail of socialist industrialization with Chinese characteristics.Under the CPC’s leadership,China established an independent and complete industrial system in less than three decades from 1949 to 1978,and developed into the world’s largest industrial power with the most complete industrial sectors in over three decades from 1979 to 2016.In its future industrial development,China aims to complete new-type industrialization by 2035,build a modern economic system,reach the level of moderately developed countries in terms of GDP per capita,and develop into a major world industrial power by the centennial of the founding of the People’s Republic of China in 2049.展开更多
Ga2O3 nano-structures, nanowires and nanosheets are produced on Au pre-coated(111) silicon substrates with chemical vapor deposition(CVD) technique. By evaporating pure Ga powder in the H2O atmosphere under ambient pr...Ga2O3 nano-structures, nanowires and nanosheets are produced on Au pre-coated(111) silicon substrates with chemical vapor deposition(CVD) technique. By evaporating pure Ga powder in the H2O atmosphere under ambient pressure the large-scale preparation of β-Ga2O3 with monoclinic crystalline structure is achieved. The crystalline structures and morphologies of produced Ga2O3 nano-structures are characterized by means of scanning electron microscope(SEM), X-ray diffraction(XRD), selected area electron diffraction(SAED) and transmission electron microscope(TEM). Raman spectrum reveals the typical vibration modes of Ga2O3. The vibration mode shifts corresponding to Ga2O3 nano-structures are not found. Two distinguish photoluminescence(PL) emissions are found at about 399 nm and 469 nm owing to the VO-VGa excitation and VO-VGa-O excitation, respectively. The growth mechanisms of Ga2O3 nanowires and nanosheets are discussed with vapor-liquid-solid(VLS) and vapor-solid(VS) mechanisms.展开更多
As the blue and yellow lights are complementary colors, a blue InGaN LED chip is coated hy a yellow phosphor film to generate white light based on luminescence conversion mechanism. The emitted light of a blue LED is ...As the blue and yellow lights are complementary colors, a blue InGaN LED chip is coated hy a yellow phosphor film to generate white light based on luminescence conversion mechanism. The emitted light of a blue LED is used as the primary source for exciting fluorescent material such as cerium doped yttrium aluminum garnet with the formula Y3Al2O12 : Ce^3+ (in short: YAG : Ce^3+ ). The matching of the spectrum of the blue LED chips and the YAG : Ce^3+ yellow phosphor is studied to improve the conversion efficiency. The packaging methods and manufacturing processes for high power single chip-white LEDs are introduced. The uniformity of the output white light is investigated. Based on the characteristics of the high power white LEDs, some approaches and processes are suggested to improve the light uniformity when they are fabricated. The effectiveness of those approaches on the improvement of LEDs is discussed in detail and some interesting conclusions are also presented.展开更多
Widespread hotels represent a new Italian phenomenon still not much investigated, both on theoretical and empirical side, which cannot be ignored anymore. Indeed they meet the need to implement techniques and manageme...Widespread hotels represent a new Italian phenomenon still not much investigated, both on theoretical and empirical side, which cannot be ignored anymore. Indeed they meet the need to implement techniques and management tools which are able to improve the culture-tourism binomial. This would permit to transform into valid instruments of national economical development, the shared declaration of intents for which culture and tourism, especially in Italy and in this particular fragile period, represent even more the main strategic levers for the sustainable development. This article intends to describe the potentiality of these widespread hotels as innovations particularly suitable with trends recently emerged in tourism sector and outline the phenomenon pattern in ltaly with particular attention on Umbria region, in order to identify his main strength and weakness and some innovation to improve performance. To this end, it starts from the analysis of the national and international economic-managerial literature concerning in particular cultural and experienced trends shown in tourism. Then it introduces the main acquisitions about widespread hotels in Italy, updating and extending them through a desk survey based on indirect sources of various natures. Lastly, it describes the case of Umbria, analyzing more in depth making use of interviews with entrepreneurs/managers of hotels and based on a semi-structured questionnaire. The aspects of indeterminateness which were found, starting from the normative one, testify how the potentiality of the widespread hotels as far as regards the value creation for the enterprise itself and the territorial stakeholder, are still not properly understood and therefore used. It is clear that, therefore, new behaviors are needed for entrepreneurs and, most importantly, for local policy makers in order to create the conditions for the full success of these hospitality models.展开更多
This paper considers an ant colony optimization algorithm based on AND/OR graph for integrated process planning and scheduling(IPPS). Generally, the process planning and scheduling are studied separately. Due to the c...This paper considers an ant colony optimization algorithm based on AND/OR graph for integrated process planning and scheduling(IPPS). Generally, the process planning and scheduling are studied separately. Due to the complexity of manufacturing system, IPPS combining both process planning and scheduling can depict the real situation of a manufacturing system. The IPPS is represented on AND/OR graph consisting of nodes, and undirected and directed arcs. The nodes denote operations of jobs, and undirected/directed arcs denote possible visiting path among the nodes. Ant colony goes through the necessary nodes on the graph from the starting node to the end node to obtain the optimal solution with the objective of minimizing makespan. In order to avoid local convergence and low convergence, some improved strategy is incorporated in the standard ant colony optimization algorithm. Extensive computational experiments are carried out to study the influence of various parameters on the system performance.展开更多
Taizhou Yangtze River Highway Bridge is a large span suspension bridge with three pylons. The elastic cables are installed to connect the steel tower and the steel box girder. The constraints can increase the safety c...Taizhou Yangtze River Highway Bridge is a large span suspension bridge with three pylons. The elastic cables are installed to connect the steel tower and the steel box girder. The constraints can increase the safety coefficient of the middle saddle, and improve the stress conditions of the middle pylon and decrease the deflection in the middle of the main girder, as well as the longitudinal displacement of the main girder caused by live loads. The anchorage boxes of the elastic cable are installed in the wind fairing outside the vertical web plate of the box girder. Two anchor boxes form a pair and are arranged parallelly. Eight anchor boxes are installed in the bridge. In this paper, the design scheme and the technical difficulties in manufacturing are briefly discussed with the precision control techniques.展开更多
On Jan.31 of 2010,the Suining earthquake occurred at Suining City whch is located the center of Sichuan Basin.It is unusual for the strong earthquake to occur at the center of Sichuan Basin with a stable geotectonic e...On Jan.31 of 2010,the Suining earthquake occurred at Suining City whch is located the center of Sichuan Basin.It is unusual for the strong earthquake to occur at the center of Sichuan Basin with a stable geotectonic environment and a low-level historical seismicity.The macro-epicenter of the earthquake is located at Moxi town of Suining city,Sichuan province,China.The earthquake intensity of the epicenter area is degree VII,and the long axis of the isoseismal line trends in NE orientation.The Suining earthquake caused the collapse or destruction of 460 family houses.The earthquake focal mechanism solution and records of the near-field seismographic stations showed the earthquake occurred at the reverse fault at a depth 34 km.Based on the waveform and focal mechanism,we consider the Suning earthquake is triggered by the reverse fault and not by the gravitational collapse or man-made explosive sources.Basing on seismic refraction profile and borehole,we consider that the earthquake is triggered by the backthrust fault of Moxi anticline rooted in detachments at a depth 3-4 km.Furthermore,we infer that tectonic mechanism of the Suining(Ms5.0) Earthquake is driven by the horizontal crustal shortening and stress adjustment on a shallow detachment after the Wenchuan(Ms 8.0) earthquake.展开更多
Nanofluidics is a recent appearing research field, introduced in 1995 as an analogue of the field of microfluidics, and has been becoming popular in the past few years. The proximity of the channel dimension, the Deby...Nanofluidics is a recent appearing research field, introduced in 1995 as an analogue of the field of microfluidics, and has been becoming popular in the past few years. The proximity of the channel dimension, the Debye length, and the size of biomolecules such as DNA and proteins gives the unique features of nanofluidic devices. Of various unique properties of the nanofluidics, mass transport in nanochannel plays determining roles in fundamental reaches and practical applications of nanofluidic device. Thus, much work including numerical and experimental researches has been performed to investigate the mass transport behaviors in nanofluidic devices. This review summarizes the fabrication technologies for nanofluidic devices, the mass transport behaviors in nanochannel, and their applications in bioanalysis. The main focus will be laid on the effects of nanochannel size and surface charge on mass transport including electrokinetic transport of charged analytes, diffusion of electric neutral molecules, ionic current rectification, concentration polarization, nonlinear electrokinetic flow at the micro-nanofluidic interfaces.展开更多
The polar motion excited by the fluctuation of global atmospheric angular momentum (AAM) is investigated. Based on the global AAM data, numerical results demonstrate that the fluctuation of AAM can excite the seasonal...The polar motion excited by the fluctuation of global atmospheric angular momentum (AAM) is investigated. Based on the global AAM data, numerical results demonstrate that the fluctuation of AAM can excite the seasonal wobbles (e.g., the 18-month wobble) and the Chandler wobble, which agree well with previous studies. In addition, by filtering the dominant low frequency components, some distinct polar wobbles corresponding to some great diurnal and semi-diurnal atmospheric tides are found.展开更多
基金Project(cstc2018jcyjAX0159)supported by the Natural Science Foundation of Chongqing,ChinaProject(51575066)supported by the National Natural Science Foundation of China。
文摘Ultra-large plate forgings are foundation of heavy machinery,but many parts of the type cannot be made by conventional technologies due to the characters of extreme manufacturing in terms of size and quality requirements.This paper introduced a systematically method called cylinder unfolding method(CUM)for producing large plate forgings,by using a serial of operations including“splitting”,“unfolding”,and“flattening”of a thick cylinder obtained from saddle forging.The technological route of CUM was presented in detail with an example of plate forging with the horizontal sizes of 6100 mm and thickness of 300 mm.The deformation features of saddle forging for fabricating transitional cylinders were analyzed,and then the subsequent handling steps including splitting,unfolding and flattening of the cylinder,as well as the auxiliary processing,were addressed.The practice proved that CUM can provide an efficient way for manufacturing ultra-large plate forgings and meet the strict requirements in geometry and mechanical performance,without highly increasing the investments of forming equipment and tooling.
文摘Industrialization has been a dream for the Chinese nation since modern history and a goal of the Communist Party of China(CPC).Ever since its founding in 1921,the CPC has been exploring a path for China’s industrial development based on socialism as the political and institutional premise.Since the founding of the People’s Republic of China in 1949,the Chinese people have established a socialist system under the CPC’s leadership and carried out industrial development for over seven decades in the world’s most populous country,blazing a new trail of socialist industrialization with Chinese characteristics.Under the CPC’s leadership,China established an independent and complete industrial system in less than three decades from 1949 to 1978,and developed into the world’s largest industrial power with the most complete industrial sectors in over three decades from 1979 to 2016.In its future industrial development,China aims to complete new-type industrialization by 2035,build a modern economic system,reach the level of moderately developed countries in terms of GDP per capita,and develop into a major world industrial power by the centennial of the founding of the People’s Republic of China in 2049.
文摘Ga2O3 nano-structures, nanowires and nanosheets are produced on Au pre-coated(111) silicon substrates with chemical vapor deposition(CVD) technique. By evaporating pure Ga powder in the H2O atmosphere under ambient pressure the large-scale preparation of β-Ga2O3 with monoclinic crystalline structure is achieved. The crystalline structures and morphologies of produced Ga2O3 nano-structures are characterized by means of scanning electron microscope(SEM), X-ray diffraction(XRD), selected area electron diffraction(SAED) and transmission electron microscope(TEM). Raman spectrum reveals the typical vibration modes of Ga2O3. The vibration mode shifts corresponding to Ga2O3 nano-structures are not found. Two distinguish photoluminescence(PL) emissions are found at about 399 nm and 469 nm owing to the VO-VGa excitation and VO-VGa-O excitation, respectively. The growth mechanisms of Ga2O3 nanowires and nanosheets are discussed with vapor-liquid-solid(VLS) and vapor-solid(VS) mechanisms.
基金"863"Project from Ministry of Science & Technology of China(2006AA03A116)
文摘As the blue and yellow lights are complementary colors, a blue InGaN LED chip is coated hy a yellow phosphor film to generate white light based on luminescence conversion mechanism. The emitted light of a blue LED is used as the primary source for exciting fluorescent material such as cerium doped yttrium aluminum garnet with the formula Y3Al2O12 : Ce^3+ (in short: YAG : Ce^3+ ). The matching of the spectrum of the blue LED chips and the YAG : Ce^3+ yellow phosphor is studied to improve the conversion efficiency. The packaging methods and manufacturing processes for high power single chip-white LEDs are introduced. The uniformity of the output white light is investigated. Based on the characteristics of the high power white LEDs, some approaches and processes are suggested to improve the light uniformity when they are fabricated. The effectiveness of those approaches on the improvement of LEDs is discussed in detail and some interesting conclusions are also presented.
文摘Widespread hotels represent a new Italian phenomenon still not much investigated, both on theoretical and empirical side, which cannot be ignored anymore. Indeed they meet the need to implement techniques and management tools which are able to improve the culture-tourism binomial. This would permit to transform into valid instruments of national economical development, the shared declaration of intents for which culture and tourism, especially in Italy and in this particular fragile period, represent even more the main strategic levers for the sustainable development. This article intends to describe the potentiality of these widespread hotels as innovations particularly suitable with trends recently emerged in tourism sector and outline the phenomenon pattern in ltaly with particular attention on Umbria region, in order to identify his main strength and weakness and some innovation to improve performance. To this end, it starts from the analysis of the national and international economic-managerial literature concerning in particular cultural and experienced trends shown in tourism. Then it introduces the main acquisitions about widespread hotels in Italy, updating and extending them through a desk survey based on indirect sources of various natures. Lastly, it describes the case of Umbria, analyzing more in depth making use of interviews with entrepreneurs/managers of hotels and based on a semi-structured questionnaire. The aspects of indeterminateness which were found, starting from the normative one, testify how the potentiality of the widespread hotels as far as regards the value creation for the enterprise itself and the territorial stakeholder, are still not properly understood and therefore used. It is clear that, therefore, new behaviors are needed for entrepreneurs and, most importantly, for local policy makers in order to create the conditions for the full success of these hospitality models.
基金Supported by the Fundamental Research Funds for the Central Universities(13MS100)the Hebei Province Research Foundation of Natural Science(E2011502024)the National Natural Science Foundation of China(51177046)
文摘This paper considers an ant colony optimization algorithm based on AND/OR graph for integrated process planning and scheduling(IPPS). Generally, the process planning and scheduling are studied separately. Due to the complexity of manufacturing system, IPPS combining both process planning and scheduling can depict the real situation of a manufacturing system. The IPPS is represented on AND/OR graph consisting of nodes, and undirected and directed arcs. The nodes denote operations of jobs, and undirected/directed arcs denote possible visiting path among the nodes. Ant colony goes through the necessary nodes on the graph from the starting node to the end node to obtain the optimal solution with the objective of minimizing makespan. In order to avoid local convergence and low convergence, some improved strategy is incorporated in the standard ant colony optimization algorithm. Extensive computational experiments are carried out to study the influence of various parameters on the system performance.
基金National Science and Technology Support Program of China ( No. 2009BAG15B02)
文摘Taizhou Yangtze River Highway Bridge is a large span suspension bridge with three pylons. The elastic cables are installed to connect the steel tower and the steel box girder. The constraints can increase the safety coefficient of the middle saddle, and improve the stress conditions of the middle pylon and decrease the deflection in the middle of the main girder, as well as the longitudinal displacement of the main girder caused by live loads. The anchorage boxes of the elastic cable are installed in the wind fairing outside the vertical web plate of the box girder. Two anchor boxes form a pair and are arranged parallelly. Eight anchor boxes are installed in the bridge. In this paper, the design scheme and the technical difficulties in manufacturing are briefly discussed with the precision control techniques.
基金the National Natural Science Foundation of China (Grant No. 40841010,40972083,41172162)the National Science and Technology Support Program (Grant nNo. 2006BAC13B02-107,2006BAC13B01-604) for the funding
文摘On Jan.31 of 2010,the Suining earthquake occurred at Suining City whch is located the center of Sichuan Basin.It is unusual for the strong earthquake to occur at the center of Sichuan Basin with a stable geotectonic environment and a low-level historical seismicity.The macro-epicenter of the earthquake is located at Moxi town of Suining city,Sichuan province,China.The earthquake intensity of the epicenter area is degree VII,and the long axis of the isoseismal line trends in NE orientation.The Suining earthquake caused the collapse or destruction of 460 family houses.The earthquake focal mechanism solution and records of the near-field seismographic stations showed the earthquake occurred at the reverse fault at a depth 34 km.Based on the waveform and focal mechanism,we consider the Suning earthquake is triggered by the reverse fault and not by the gravitational collapse or man-made explosive sources.Basing on seismic refraction profile and borehole,we consider that the earthquake is triggered by the backthrust fault of Moxi anticline rooted in detachments at a depth 3-4 km.Furthermore,we infer that tectonic mechanism of the Suining(Ms5.0) Earthquake is driven by the horizontal crustal shortening and stress adjustment on a shallow detachment after the Wenchuan(Ms 8.0) earthquake.
基金supported by the National Basic Research Program (2012CB933804)the National Natural Science Foundation of China (20890020, 20975047, 21035002)+2 种基金the National Science Fund for Creative Research Groups (21121091)Specialized Research Fund for the Doctoral Program of Higher Fducation (200802840012)the Natural Science Foundation of Jiangsu Province (BK2010009)
文摘Nanofluidics is a recent appearing research field, introduced in 1995 as an analogue of the field of microfluidics, and has been becoming popular in the past few years. The proximity of the channel dimension, the Debye length, and the size of biomolecules such as DNA and proteins gives the unique features of nanofluidic devices. Of various unique properties of the nanofluidics, mass transport in nanochannel plays determining roles in fundamental reaches and practical applications of nanofluidic device. Thus, much work including numerical and experimental researches has been performed to investigate the mass transport behaviors in nanofluidic devices. This review summarizes the fabrication technologies for nanofluidic devices, the mass transport behaviors in nanochannel, and their applications in bioanalysis. The main focus will be laid on the effects of nanochannel size and surface charge on mass transport including electrokinetic transport of charged analytes, diffusion of electric neutral molecules, ionic current rectification, concentration polarization, nonlinear electrokinetic flow at the micro-nanofluidic interfaces.
基金Supported by the Special Project Fund of State Key Laboratory of Information Engineering in Surveying,Mapping and Remote Sensing(China)the Ph.D.Candidates Self-research(including1+4)Program of Wuhan Unversity in2008(No.49)+1 种基金the Engagement Fund of Outstanding Doctoral Dissertation of Wuhan University(No.22)the Open Fund of Key Laboratory of Geospace Environment and Geodesy,Ministry of Education,China(No.08-02-02)
文摘The polar motion excited by the fluctuation of global atmospheric angular momentum (AAM) is investigated. Based on the global AAM data, numerical results demonstrate that the fluctuation of AAM can excite the seasonal wobbles (e.g., the 18-month wobble) and the Chandler wobble, which agree well with previous studies. In addition, by filtering the dominant low frequency components, some distinct polar wobbles corresponding to some great diurnal and semi-diurnal atmospheric tides are found.