Electromigration is the transport of atoms in metal conductors at high electronic current-densities which creates voids in the conductors and increases the conductors＇ electrical resistance. It was delineated in 1961...Electromigration is the transport of atoms in metal conductors at high electronic current-densities which creates voids in the conductors and increases the conductors＇ electrical resistance. It was delineated in 1961 by Huntington; then modeled by the empirical electrical resistance formula derived by Black in 1969 to fit the dependences of the experimental electrical resistance and failure data on the electrical current density and temperature. Tan in 2007 reviewed 40-years＇ ap- plications of the empirical Black formula to conductor lines interconnecting transistors and other devices in silicon integrated circuits. Since the first Landauer theory in 1957,theorists have attempted for 50 years to justify the drift force or electron momentum transfer assumed by Black as some electron-wind force to impart on the metal atoms and ions to move them. Landauer concluded in 1989 that the electron wind force is untenable even considering the most fundamental and complete many-body quantum transport theory. A driftless or electron-windless atomic void model for metal conductor lines is reviewed in this article. It was developed in the mid-1980 and described in 1996 by Sah in a homework solution. This model accounts for all the current and temperature dependences of experimental resistance data fitted to the empiri- cal Black formula. Exact analytical solutions were obtained for the metal conductor line resistance or current, R （t）/R （0） = J（t）/J（0） = [1-2（t/τα）^1/α]^-1/2 ,in the bond-breaking limit with α = 1 to 2 and diffusion limit with α = 2 to 4,from low to high current densities, where τα is the characteristic time constant of the mechanism, containing bond breaking and diffusion rates and activation energies of the metal.展开更多
The grand canonical Monte Carlo (GCMC), the canonical Monte Carlo by using equal probability perturbation, and the molecular dynamics (MD) methods were used to study the capillary phase-transition (capillary condensat...The grand canonical Monte Carlo (GCMC), the canonical Monte Carlo by using equal probability perturbation, and the molecular dynamics (MD) methods were used to study the capillary phase-transition (capillary condensation and evaporation) and self-diffusion for a simple Lennard-Jones model of ethylene confined in slit carbon pores of 2.109 nm at temperatures between 141.26 K and 201.80 K. The critical point of capillary phase-transition was extrapolated by the critical power law and the law of rectilinear diameter from the capillary phase-transition data in the near critical region. The effects of temperature and fluid density on the parallel self-diffusion coefficients of ethylene molecules confined in the slit carbon pores were examined. The results showed that the parallel selfdiffusion coefficients in the capillary phase transition area strongly depended on the fluids local densities in the slit carbon pores.展开更多
Places of large potentials of sustainable energy production and places of large energy consumption are often very different and separated by large distances across the globe. This paper first discusses potentials of s...Places of large potentials of sustainable energy production and places of large energy consumption are often very different and separated by large distances across the globe. This paper first discusses potentials of solar technology in terms of global availability using PV （photovoltaic） technology and actual energy production. Solar energy is widely under-used and one way to reduce this is to improve production in low-energy places with high demand： large cities. According to this option, about 40% of the electricity consumption in the built environment could be produced by solar PV systems and energy storage systems. This paper discusses conditions in the built environment and functional and design qualities enabling an increased diffusion of the technologies In a comparative analysis of PV technologies, the criteria taken into account encompass efficiency of the type of solar cell and commercial availability. Special attention is paid to the design features of different PV systems, like flexibility, colour and transparency that might help in their utilization as integrated in building material and ornaments in modem architecture. The same procedure is followed for electricity storage devices. The preliminary conclusion is that at present the freedom of design is largest for a combination of crystalline silicon PV cells and Li-ion batteries.展开更多
The physical characteristics of coal reservoirs are important for evaluating the potential for gas desorption, diffusion, and seepage during coalbed methane （CBM） production, and influence the performance of CBM wel...The physical characteristics of coal reservoirs are important for evaluating the potential for gas desorption, diffusion, and seepage during coalbed methane （CBM） production, and influence the performance of CBM wells. Based on data from mercury injection experiments, low-temperature liquid nitrogen adsorption, isothermal adsorption, initial velocity tests of methane diffusion, and gas natural desorption data from a CBM field, herein the physical characteristics of reservoirs of high-rank coals with different coal-body structures are described, including porosity, adsorption/desorption, diffusion, and seepage. Geometric models are constructed for these reservoirs. The modes of diffusion are discussed and a comprehensive diffusion-seepage model is constructed. The following conclusions were obtained. First, the pore distribution of tectonically deformed coal is different from that of normal coal. Compared to normal coal, all types of pore, including micropores （〈10 nm）, transitional pores （10-100 nm）, mesopores （100-1000 nm）, and macropores （〉1000 nm）, are more abundant in tectonically deformed coal, especially mesopores and macropores. The increase in pore abundance is greater with increasing tectonic deformation of coal; in addition, the pore connectivity is altered. These are the key factors causing differences in other reservoir physical characteristics, such as adsorption/desorption and diffusion in coals with different coal-body structures. Second, normal and cataclastic coals mainly contain micropores. The lack of macropores and its bad connectivity limit gas desorption and diffusion during the early stage of CBM production. However, the good connectivity of micropores is favorable for gas desorption and diffusion in later gas production stage. Thus, because of the slow decline in the rate of gas desorption, long-term gas production can easily be obtained from these reservoirs. Third, under natural conditions the adsorption/desorption properties of granulated and mylonitized coal are good, and the diffusion ability is also enhanced. However, for in situ reservoir conditions, the high dependence of reservoir permeability on stress results in a weak seepage of gas; thus, desorption and diffusion is limited. Fourth, during gas production, the pore range in which transitional diffusion takes place always increases, but that for Fick diffusion decreases. This is a reason for the reduction in diffusion capacity, in which micropores and transitional pores are the primary factors limiting gas diffusion. Finally, the proposed comprehensive model of CBM production under in situ reservoir conditions elucidates the key factors limiting gas production, which is helpful for selection of reservoir stimulation methods.展开更多
Natal dispersal, the movement of an organism from its birthplace to the site of first reproduction, is fundamental to many ecological and evolutionary processes. Mechanistically, individual dispersal decisions can dep...Natal dispersal, the movement of an organism from its birthplace to the site of first reproduction, is fundamental to many ecological and evolutionary processes. Mechanistically, individual dispersal decisions can depend on both individual phe- notype and environmental cues. In particular, many established evolutionary theories of dispersal highlight the importance of the social environment. More recent research in behavioral ecology has focused on the importance of individual behavioral pheno- types. We reviewed the literature on individual behavioral phenotypes and dispersal and suggest that how individual behavioral phenotypes interact with the immediate social environment experienced by individuals in influencing dispersal is still poorly un- derstood, despite growing interest. We found that very few studies had examined the interaction of individual behavioral pheno- types and social factors, and behavioral phenotypes related to social tendencies were less commonly measured than were beha- vioral phenotypes related to exploration or response to risk. Further, and unsurprisingly, studies on social behavioral phenotypes and dispersal behaviors during the transience stage of dispersal were underrepresented compared to the departure or settlement stages. Future studies in this area should aim to＂ a） make explicit links between behavioral traits and their proposed effects on dispersal decisions throughout multiple stages of dispersal, b） integrate more continuous dispersal variables, and c） consider the effects of the spatial distribution and phenotypes of conspecifics （i.e., the social landscape） encountered by individual dispersers展开更多
By optimizing the diffusion temperature and time,four groups of samples with different sheet resistances are achieved.The front screen printing pattern and firing temperature are fine-tuned according to the needs.The ...By optimizing the diffusion temperature and time,four groups of samples with different sheet resistances are achieved.The front screen printing pattern and firing temperature are fine-tuned according to the needs.The performance of the low-and-plateau-temperature doping recipe(as recipe A)is better than that of the low-and-multiple-temperature doping recipe(as recipe B).And the 19.24%efficiency of volume production of monocrystalline solar cells with 238.95 mm2 and 80?/sq sheet resistance is obtained in the traditional process line.0.48%more efficiency is achieved than 60?/sq due to the reduction of the phosphorus surface doping and shallow junction by the low-and-plateau-temperature diffusion recipe.The module test shows that by using two drive-in zones,not only do we have a higher efficiency,but also have a stabler and lower power loss in encapsulation manufacture.It is showed that power of a large improvement will be gotten by statistical analysis and PC1D simulation.展开更多
文摘Electromigration is the transport of atoms in metal conductors at high electronic current-densities which creates voids in the conductors and increases the conductors＇ electrical resistance. It was delineated in 1961 by Huntington; then modeled by the empirical electrical resistance formula derived by Black in 1969 to fit the dependences of the experimental electrical resistance and failure data on the electrical current density and temperature. Tan in 2007 reviewed 40-years＇ ap- plications of the empirical Black formula to conductor lines interconnecting transistors and other devices in silicon integrated circuits. Since the first Landauer theory in 1957,theorists have attempted for 50 years to justify the drift force or electron momentum transfer assumed by Black as some electron-wind force to impart on the metal atoms and ions to move them. Landauer concluded in 1989 that the electron wind force is untenable even considering the most fundamental and complete many-body quantum transport theory. A driftless or electron-windless atomic void model for metal conductor lines is reviewed in this article. It was developed in the mid-1980 and described in 1996 by Sah in a homework solution. This model accounts for all the current and temperature dependences of experimental resistance data fitted to the empiri- cal Black formula. Exact analytical solutions were obtained for the metal conductor line resistance or current, R （t）/R （0） = J（t）/J（0） = [1-2（t/τα）^1/α]^-1/2 ,in the bond-breaking limit with α = 1 to 2 and diffusion limit with α = 2 to 4,from low to high current densities, where τα is the characteristic time constant of the mechanism, containing bond breaking and diffusion rates and activation energies of the metal.
基金the National Science Foundation of China (NSFC) the China Petrochemical Corporation (SINOPEC) (No. 29792077).
文摘The grand canonical Monte Carlo (GCMC), the canonical Monte Carlo by using equal probability perturbation, and the molecular dynamics (MD) methods were used to study the capillary phase-transition (capillary condensation and evaporation) and self-diffusion for a simple Lennard-Jones model of ethylene confined in slit carbon pores of 2.109 nm at temperatures between 141.26 K and 201.80 K. The critical point of capillary phase-transition was extrapolated by the critical power law and the law of rectilinear diameter from the capillary phase-transition data in the near critical region. The effects of temperature and fluid density on the parallel self-diffusion coefficients of ethylene molecules confined in the slit carbon pores were examined. The results showed that the parallel selfdiffusion coefficients in the capillary phase transition area strongly depended on the fluids local densities in the slit carbon pores.
文摘Places of large potentials of sustainable energy production and places of large energy consumption are often very different and separated by large distances across the globe. This paper first discusses potentials of solar technology in terms of global availability using PV （photovoltaic） technology and actual energy production. Solar energy is widely under-used and one way to reduce this is to improve production in low-energy places with high demand： large cities. According to this option, about 40% of the electricity consumption in the built environment could be produced by solar PV systems and energy storage systems. This paper discusses conditions in the built environment and functional and design qualities enabling an increased diffusion of the technologies In a comparative analysis of PV technologies, the criteria taken into account encompass efficiency of the type of solar cell and commercial availability. Special attention is paid to the design features of different PV systems, like flexibility, colour and transparency that might help in their utilization as integrated in building material and ornaments in modem architecture. The same procedure is followed for electricity storage devices. The preliminary conclusion is that at present the freedom of design is largest for a combination of crystalline silicon PV cells and Li-ion batteries.
基金supported by the National Natural Science Foundation of China(Grant No.41372162)the Science and Technology Innovation Team Support Plan of Henan Province(Grant No.14IRTSTHN002)
文摘The physical characteristics of coal reservoirs are important for evaluating the potential for gas desorption, diffusion, and seepage during coalbed methane （CBM） production, and influence the performance of CBM wells. Based on data from mercury injection experiments, low-temperature liquid nitrogen adsorption, isothermal adsorption, initial velocity tests of methane diffusion, and gas natural desorption data from a CBM field, herein the physical characteristics of reservoirs of high-rank coals with different coal-body structures are described, including porosity, adsorption/desorption, diffusion, and seepage. Geometric models are constructed for these reservoirs. The modes of diffusion are discussed and a comprehensive diffusion-seepage model is constructed. The following conclusions were obtained. First, the pore distribution of tectonically deformed coal is different from that of normal coal. Compared to normal coal, all types of pore, including micropores （〈10 nm）, transitional pores （10-100 nm）, mesopores （100-1000 nm）, and macropores （〉1000 nm）, are more abundant in tectonically deformed coal, especially mesopores and macropores. The increase in pore abundance is greater with increasing tectonic deformation of coal; in addition, the pore connectivity is altered. These are the key factors causing differences in other reservoir physical characteristics, such as adsorption/desorption and diffusion in coals with different coal-body structures. Second, normal and cataclastic coals mainly contain micropores. The lack of macropores and its bad connectivity limit gas desorption and diffusion during the early stage of CBM production. However, the good connectivity of micropores is favorable for gas desorption and diffusion in later gas production stage. Thus, because of the slow decline in the rate of gas desorption, long-term gas production can easily be obtained from these reservoirs. Third, under natural conditions the adsorption/desorption properties of granulated and mylonitized coal are good, and the diffusion ability is also enhanced. However, for in situ reservoir conditions, the high dependence of reservoir permeability on stress results in a weak seepage of gas; thus, desorption and diffusion is limited. Fourth, during gas production, the pore range in which transitional diffusion takes place always increases, but that for Fick diffusion decreases. This is a reason for the reduction in diffusion capacity, in which micropores and transitional pores are the primary factors limiting gas diffusion. Finally, the proposed comprehensive model of CBM production under in situ reservoir conditions elucidates the key factors limiting gas production, which is helpful for selection of reservoir stimulation methods.
文摘Natal dispersal, the movement of an organism from its birthplace to the site of first reproduction, is fundamental to many ecological and evolutionary processes. Mechanistically, individual dispersal decisions can depend on both individual phe- notype and environmental cues. In particular, many established evolutionary theories of dispersal highlight the importance of the social environment. More recent research in behavioral ecology has focused on the importance of individual behavioral pheno- types. We reviewed the literature on individual behavioral phenotypes and dispersal and suggest that how individual behavioral phenotypes interact with the immediate social environment experienced by individuals in influencing dispersal is still poorly un- derstood, despite growing interest. We found that very few studies had examined the interaction of individual behavioral pheno- types and social factors, and behavioral phenotypes related to social tendencies were less commonly measured than were beha- vioral phenotypes related to exploration or response to risk. Further, and unsurprisingly, studies on social behavioral phenotypes and dispersal behaviors during the transience stage of dispersal were underrepresented compared to the departure or settlement stages. Future studies in this area should aim to＂ a） make explicit links between behavioral traits and their proposed effects on dispersal decisions throughout multiple stages of dispersal, b） integrate more continuous dispersal variables, and c） consider the effects of the spatial distribution and phenotypes of conspecifics （i.e., the social landscape） encountered by individual dispersers
基金supported by the National High Technology Research and("863"program)(Grant Nos.2012AA0503032011AA050504)+1 种基金Independent Innovation Project of Shandong Province(Grant Nos.2010ZHZX1A07022011ZHZX1A0701)
文摘By optimizing the diffusion temperature and time,four groups of samples with different sheet resistances are achieved.The front screen printing pattern and firing temperature are fine-tuned according to the needs.The performance of the low-and-plateau-temperature doping recipe(as recipe A)is better than that of the low-and-multiple-temperature doping recipe(as recipe B).And the 19.24%efficiency of volume production of monocrystalline solar cells with 238.95 mm2 and 80?/sq sheet resistance is obtained in the traditional process line.0.48%more efficiency is achieved than 60?/sq due to the reduction of the phosphorus surface doping and shallow junction by the low-and-plateau-temperature diffusion recipe.The module test shows that by using two drive-in zones,not only do we have a higher efficiency,but also have a stabler and lower power loss in encapsulation manufacture.It is showed that power of a large improvement will be gotten by statistical analysis and PC1D simulation.
