A theoretical “drift-flux based thermal-hydraulic mixture-fluid coolant channel model” is presented. It is the basis to a corresponding digital “Coolant Channel Module (CCM)”. This purpose derived “Separate-Regio...A theoretical “drift-flux based thermal-hydraulic mixture-fluid coolant channel model” is presented. It is the basis to a corresponding digital “Coolant Channel Module (CCM)”. This purpose derived “Separate-Region Mixture Fluid Approach” should yield an alternative platform to the currently dominant “Separate-Phase Models” where each phase is treated separately. Contrary to it, a direct procedure could be established with the objective to simulate in an as general as possible way the steady state and transient behaviour of characteristic parameters of single- and/or (now non-separated) two-phase fluids flowing within any type of heated or non-heated coolant channels. Their validity could be confirmed by a wide range of verification and validation runs, showing very satisfactory results. The resulting universally applicable code package CCM should provide a fundamental element for the simulation of thermal-hydraulic situations over a wide range of complex systems (such as different types of heat exchangers and steam generators as being applied in both conventional but also nuclear power stations, 1D and 3D nuclear reactor cores etc). Thereby the derived set of equations for different coolant channels (distinguished by their key numbers) as appearing in these systems can be combined with other ODE-s and non-linear algebraic relations from additional parts of such an overall model. And these can then to be solved by applying an appropriate integration routine. Within the solution procedure, however, mathematical discontinuities can arise. This due to the fact that along such a coolant channel transitions from single- to two-phase flow regimes and vice versa could take place. To circumvent these difficulties it will in the presented approach be proposed that the basic coolant channel (BC) is subdivided into a number of sub-channels (SC-s), each of them being occupied exclusively by only a single or a two-phase flow regime. After an appropriate nodalization of the BC (and thus its SC-s) and after applying a “modified finite volume method” together with other special activities the fundamental set of non-linear thermal-hydraulic partial differential equations together with corresponding constitutive relations can be solved for each SC separately. As a result of such a spatial discretization for each SC type (and thus the entire BC) the wanted set of non-linear ordinary differential equations of 1st order could be established. Obviously, special attention had to be given to the varying SC entrance or outlet positions, describing the movement of boiling boundaries or mixture levels along the channel. Including even the possibility of SC-s to disappear or be created anew during a transient.展开更多
This paper investigates the power sharing and voltage regulation issues of islanded single-/three-phase microgrids(S/T-MGs)where both sources and loads are unbalanced and the presence of adversarial cyber-attacks agai...This paper investigates the power sharing and voltage regulation issues of islanded single-/three-phase microgrids(S/T-MGs)where both sources and loads are unbalanced and the presence of adversarial cyber-attacks against sensors of distributed generator(DG)units is considered.Firstly,each DG unit is modeled as a heterogeneous linear dynamic agent with disturbances caused by sources and loads,then the problem is formulated as a distributed containment control problem.After that,to guarantee satisfactory power sharing and voltage control performance asymptotically achieved for the S/T-MGs,an attack-resilient distributed secondary control approach is developed by designing a distributed adaptive observer.With this approach,the effect of the cyber-attacks can be neutralized to ensure system stability and preserve bounded voltage synchronization.Simulation results are presented to demonstrate the effectiveness of the proposed control approach.展开更多
We explore for the first time the real-time spectra of dissipative soliton(DS)and noise-like pulse(NLP)inter-switching by adjusting the pump power,as well as the dual-pulse collision dynamics for three modes:dual-NLP,...We explore for the first time the real-time spectra of dissipative soliton(DS)and noise-like pulse(NLP)inter-switching by adjusting the pump power,as well as the dual-pulse collision dynamics for three modes:dual-NLP,NLP-DS,and dual-DS in a single-/dual-wavelength mode-locked fiber laser.Different types of dual-pulses differ in collision duration.During spectral reconstruction,dual-pulses exchange energy twice due to their respective accumulation dynamics.Additionally,collisioninduced soliton explosions have chaotic properties,leading to each collision being random.The experimental results advance the study of the dynamics of different pulse types and also contribute to the conduction of in-depth investigations on dual-comb sources.展开更多
The article reviews the present state of the art in the magnetron sputtering of hart and superhard nanocomposite coatings. It is shown that there are (1) two gr oups of hard and superhard nanocomposites: (i) nc-MN/har...The article reviews the present state of the art in the magnetron sputtering of hart and superhard nanocomposite coatings. It is shown that there are (1) two gr oups of hard and superhard nanocomposites: (i) nc-MN/hard phase and (ii) nc-MN/s oft phase, (2) three possible origins of the enhanced hardness: (i) dislocation- dominated plastic deformation, (ii) cohesive forces between atoms and (iii) nano structure of materials, and (3) huge differences in the microstructure of single - and two-phase films. A main attention is devoted to the formation of nanocryst alline and/or X-ray amorphous films. Such films are created in a vicinity of tra nsitions between (i) crystalline and amorphous phases, (ii) two crystalline phas es of different chemical composition or (iii) two different preferred orientatio ns of grains of the same material from which the coating is composed. The existe nce of the last transition makes it possible to explain the enhanced hardness in single-phase films. The thermal stability and oxidation resistance of hard nano composite films is also shortly discussed.展开更多
An entirely new framework is established for developing various single- and multi-step formulations for the numerical integration of ordinary differential equations. Besides polynomials, unconventional base-functions ...An entirely new framework is established for developing various single- and multi-step formulations for the numerical integration of ordinary differential equations. Besides polynomials, unconventional base-functions with trigonometric and exponential terms satisfying different conditions are employed to generate a number of formulations. Performances of the new schemes are tested against well-known numerical integrators for selected test cases with quite satisfactory results. Convergence and stability issues of the new formulations are not addressed as the treatment of these aspects requires a separate work. The general approach introduced herein opens a wide vista for producing virtually unlimited number of formulations.展开更多
The problem of CO2 embodied in international trade has attracted increasing attention in China. To analyze this issue, the present paper directly calculates emission factors for 15 industries in 2002, 2005 and2007. We...The problem of CO2 embodied in international trade has attracted increasing attention in China. To analyze this issue, the present paper directly calculates emission factors for 15 industries in 2002, 2005 and2007. We then examine a consumption-based system and a single-region input-output model to estimate China＇s embodied emissions during 2000- 2009. Our results show that, when a consumption-based system is adopted, China＇s emissions are lower than those reported by some international organizations. The rapid growth in China ＇s exports＇ is a key determinant of China＇s rising total emissions. All countries shouM strengthen their cooperation in improving their current greenhouse gas inventories. Furthermore, China needs to encourage trade in low-carbon products and technology.展开更多
A new two-photon material, 3E,6E-bis（2-pyrid-4′-ylvinyl）dibenzothiophene （BPVDBT）, has been firstly synthesized by an efficient Pd-catalyzed Heck coupling route. The single- and two-photon fluorescence, quantum y...A new two-photon material, 3E,6E-bis（2-pyrid-4′-ylvinyl）dibenzothiophene （BPVDBT）, has been firstly synthesized by an efficient Pd-catalyzed Heck coupling route. The single- and two-photon fluorescence, quantum yields, lifetimes, solvent effects of the chromophore were studied in detail and the compound exhibited solvent-sensitivity. The fluorescence intensity （Ⅰout） and input excitation intensity （Ⅰin） can fit in well with the quadratic parabolas, which indicates that the up-converted fluorescence was induced by the two-photon absorption （TPA）. TPA cross-section of BPVDBT has been measured using the two-photon-induced fluorescence method, whose value is 14.24×10^-50 cm^4·s·photon^-1·molecule^-1 at 750 nm. The experimental results confirm that BPVDBT is a good two-photon absorbing chromophore with an A-π-A type.展开更多
The possible shape coexistence in even-even Ne isotopes and the impurity effects of the sΛ and pΛ hyperons are explored employing the multidimensionally constrained relativistic-mean-field(MDC-RMF) model with the PK...The possible shape coexistence in even-even Ne isotopes and the impurity effects of the sΛ and pΛ hyperons are explored employing the multidimensionally constrained relativistic-mean-field(MDC-RMF) model with the PK1 parameter set for the N N interaction and PK1-Y1 for the ΛN interaction. The quadrupole deformation potential energy surfaces(PESs), nuclear deformations, nuclear radii, binding energies, and density distributions of the hypernuclei and core nuclei are examined. The possible shape coexistence in ^(24,26,28)Ne is predicted with small energy differences of 140, 336, and 128 keV, respectively, between the two local energy minima. Different impurity effects of the sΛand pΛ hyperons are revealed. The sΛ hyperon exhibits clear shrinkage effects, which reduce the nuclear size and facilitate a spherical nuclear shape. The prolate pΛhyperon on the 1/2^(-)[110] orbital renders the nuclear shape more prolate, while the oblate pΛ hyperon on the 3/2^(-)[101] or 1/2^(-)[101] orbital renders the nuclei more oblate. Moreover, the Λ hyperon can increase the probabilities of the shape coexistence by reducing the energy differences between the two local energy minima, although the shape coexistence may disappear owing to the vanishment of one energy minimum on the flat energy surface.展开更多
文摘A theoretical “drift-flux based thermal-hydraulic mixture-fluid coolant channel model” is presented. It is the basis to a corresponding digital “Coolant Channel Module (CCM)”. This purpose derived “Separate-Region Mixture Fluid Approach” should yield an alternative platform to the currently dominant “Separate-Phase Models” where each phase is treated separately. Contrary to it, a direct procedure could be established with the objective to simulate in an as general as possible way the steady state and transient behaviour of characteristic parameters of single- and/or (now non-separated) two-phase fluids flowing within any type of heated or non-heated coolant channels. Their validity could be confirmed by a wide range of verification and validation runs, showing very satisfactory results. The resulting universally applicable code package CCM should provide a fundamental element for the simulation of thermal-hydraulic situations over a wide range of complex systems (such as different types of heat exchangers and steam generators as being applied in both conventional but also nuclear power stations, 1D and 3D nuclear reactor cores etc). Thereby the derived set of equations for different coolant channels (distinguished by their key numbers) as appearing in these systems can be combined with other ODE-s and non-linear algebraic relations from additional parts of such an overall model. And these can then to be solved by applying an appropriate integration routine. Within the solution procedure, however, mathematical discontinuities can arise. This due to the fact that along such a coolant channel transitions from single- to two-phase flow regimes and vice versa could take place. To circumvent these difficulties it will in the presented approach be proposed that the basic coolant channel (BC) is subdivided into a number of sub-channels (SC-s), each of them being occupied exclusively by only a single or a two-phase flow regime. After an appropriate nodalization of the BC (and thus its SC-s) and after applying a “modified finite volume method” together with other special activities the fundamental set of non-linear thermal-hydraulic partial differential equations together with corresponding constitutive relations can be solved for each SC separately. As a result of such a spatial discretization for each SC type (and thus the entire BC) the wanted set of non-linear ordinary differential equations of 1st order could be established. Obviously, special attention had to be given to the varying SC entrance or outlet positions, describing the movement of boiling boundaries or mixture levels along the channel. Including even the possibility of SC-s to disappear or be created anew during a transient.
基金This work was supported in part by the National Natural Science Foundation of China(No.51907098)in part by the China Postdoctoral Science Foundation(No.2020T130337).
文摘This paper investigates the power sharing and voltage regulation issues of islanded single-/three-phase microgrids(S/T-MGs)where both sources and loads are unbalanced and the presence of adversarial cyber-attacks against sensors of distributed generator(DG)units is considered.Firstly,each DG unit is modeled as a heterogeneous linear dynamic agent with disturbances caused by sources and loads,then the problem is formulated as a distributed containment control problem.After that,to guarantee satisfactory power sharing and voltage control performance asymptotically achieved for the S/T-MGs,an attack-resilient distributed secondary control approach is developed by designing a distributed adaptive observer.With this approach,the effect of the cyber-attacks can be neutralized to ensure system stability and preserve bounded voltage synchronization.Simulation results are presented to demonstrate the effectiveness of the proposed control approach.
基金supported by the National Natural Science Foundation of China(No.62375220)Shaanxi Key Science and Technology Innovation Team Project(No.2023-CX-TD06)National Major Scientific Research Instrument Development Project of China(No.51927804)。
文摘We explore for the first time the real-time spectra of dissipative soliton(DS)and noise-like pulse(NLP)inter-switching by adjusting the pump power,as well as the dual-pulse collision dynamics for three modes:dual-NLP,NLP-DS,and dual-DS in a single-/dual-wavelength mode-locked fiber laser.Different types of dual-pulses differ in collision duration.During spectral reconstruction,dual-pulses exchange energy twice due to their respective accumulation dynamics.Additionally,collisioninduced soliton explosions have chaotic properties,leading to each collision being random.The experimental results advance the study of the dynamics of different pulse types and also contribute to the conduction of in-depth investigations on dual-comb sources.
基金This work was supported in part by the Ministryof the Education of the Czech Republic(No.MSM#234200002)and in part by the goverment of the Czech Republic and Japan under Intermational Projects KONTAKT Czech Republic-Japan ME#173 and ME#529.
文摘The article reviews the present state of the art in the magnetron sputtering of hart and superhard nanocomposite coatings. It is shown that there are (1) two gr oups of hard and superhard nanocomposites: (i) nc-MN/hard phase and (ii) nc-MN/s oft phase, (2) three possible origins of the enhanced hardness: (i) dislocation- dominated plastic deformation, (ii) cohesive forces between atoms and (iii) nano structure of materials, and (3) huge differences in the microstructure of single - and two-phase films. A main attention is devoted to the formation of nanocryst alline and/or X-ray amorphous films. Such films are created in a vicinity of tra nsitions between (i) crystalline and amorphous phases, (ii) two crystalline phas es of different chemical composition or (iii) two different preferred orientatio ns of grains of the same material from which the coating is composed. The existe nce of the last transition makes it possible to explain the enhanced hardness in single-phase films. The thermal stability and oxidation resistance of hard nano composite films is also shortly discussed.
文摘An entirely new framework is established for developing various single- and multi-step formulations for the numerical integration of ordinary differential equations. Besides polynomials, unconventional base-functions with trigonometric and exponential terms satisfying different conditions are employed to generate a number of formulations. Performances of the new schemes are tested against well-known numerical integrators for selected test cases with quite satisfactory results. Convergence and stability issues of the new formulations are not addressed as the treatment of these aspects requires a separate work. The general approach introduced herein opens a wide vista for producing virtually unlimited number of formulations.
基金the Key Program of Zhejiang Philosophy and Social Sciences"Research on the Transformation of Zhejiang Open Economic Development Mode"(09JDQY001ZD)supported by the Zhejiang first key innovative team of Economic Transformation and Development
文摘The problem of CO2 embodied in international trade has attracted increasing attention in China. To analyze this issue, the present paper directly calculates emission factors for 15 industries in 2002, 2005 and2007. We then examine a consumption-based system and a single-region input-output model to estimate China＇s embodied emissions during 2000- 2009. Our results show that, when a consumption-based system is adopted, China＇s emissions are lower than those reported by some international organizations. The rapid growth in China ＇s exports＇ is a key determinant of China＇s rising total emissions. All countries shouM strengthen their cooperation in improving their current greenhouse gas inventories. Furthermore, China needs to encourage trade in low-carbon products and technology.
基金Project supported by the State Key Program of China （No. 2004CB719803）, the National Natural Science Foundation of China （Nos. 50673053, NSFC/RGC50218001, 50173015, 60377041）.
文摘A new two-photon material, 3E,6E-bis（2-pyrid-4′-ylvinyl）dibenzothiophene （BPVDBT）, has been firstly synthesized by an efficient Pd-catalyzed Heck coupling route. The single- and two-photon fluorescence, quantum yields, lifetimes, solvent effects of the chromophore were studied in detail and the compound exhibited solvent-sensitivity. The fluorescence intensity （Ⅰout） and input excitation intensity （Ⅰin） can fit in well with the quadratic parabolas, which indicates that the up-converted fluorescence was induced by the two-photon absorption （TPA）. TPA cross-section of BPVDBT has been measured using the two-photon-induced fluorescence method, whose value is 14.24×10^-50 cm^4·s·photon^-1·molecule^-1 at 750 nm. The experimental results confirm that BPVDBT is a good two-photon absorbing chromophore with an A-π-A type.
基金supported by the National Natural Science Foundation of China(Grant No.U2032141)the Natural Science Foundation of Henan Province(Grant Nos.202300410479,and 202300410480)+2 种基金the Foundation of Fundamental Research for Young Teachers of Zhengzhou University(Grant No.JC202041041)the Physics Research and Development Program of Zhengzhou University(Grant No.32410217)supported by the nuclear data storage system in Zhengzhou University。
文摘The possible shape coexistence in even-even Ne isotopes and the impurity effects of the sΛ and pΛ hyperons are explored employing the multidimensionally constrained relativistic-mean-field(MDC-RMF) model with the PK1 parameter set for the N N interaction and PK1-Y1 for the ΛN interaction. The quadrupole deformation potential energy surfaces(PESs), nuclear deformations, nuclear radii, binding energies, and density distributions of the hypernuclei and core nuclei are examined. The possible shape coexistence in ^(24,26,28)Ne is predicted with small energy differences of 140, 336, and 128 keV, respectively, between the two local energy minima. Different impurity effects of the sΛand pΛ hyperons are revealed. The sΛ hyperon exhibits clear shrinkage effects, which reduce the nuclear size and facilitate a spherical nuclear shape. The prolate pΛhyperon on the 1/2^(-)[110] orbital renders the nuclear shape more prolate, while the oblate pΛ hyperon on the 3/2^(-)[101] or 1/2^(-)[101] orbital renders the nuclei more oblate. Moreover, the Λ hyperon can increase the probabilities of the shape coexistence by reducing the energy differences between the two local energy minima, although the shape coexistence may disappear owing to the vanishment of one energy minimum on the flat energy surface.
