In Part I of this paper, an inequality satisfied by the vacuum energy density of the universe was derived using an indirect and heuristic procedure. The derivation is based on a proposed thought experiment, according ...In Part I of this paper, an inequality satisfied by the vacuum energy density of the universe was derived using an indirect and heuristic procedure. The derivation is based on a proposed thought experiment, according to which an electron is accelerated to a constant and relativistic speed at a distance L from a perfectly conducting plane. The charge of the electron was represented by a spherical charge distribution located within the Compton wavelength of the electron. Subsequently, the electron is incident on the perfect conductor giving rise to transition radiation. The energy associated with the transition radiation depends on the parameter L. It was shown that an inequality satisfied by the vacuum energy density will emerge when the length L is pushed to cosmological dimensions and the product of the radiated energy, and the time duration of emission is constrained by Heisenberg’s uncertainty principle. In this paper, a similar analysis is conducted with a chain of electrons oscillating sinusoidally and located above a conducting plane. In the thought experiment presented in this paper, the behavior of the energy radiated by the chain of oscillating electrons is studied in the frequency domain as a function of the length L of the chain. It is shown that when the length L is pushed to cosmological dimensions and the energy radiated within a single burst of duration of half a period of oscillation is constrained by the fact that electromagnetic energy consists of photons, an inequality satisfied by the vacuum energy density emerges as a result. The derived inequality is given by where is the vacuum energy density. This result is consistent with the measured value of the vacuum energy density, which is 5.38 × 10<sup>-10</sup> J/m. The result obtained here is in better agreement with experimental data than the one obtained in Part I of this paper with time domain radiation.展开更多
Owing to the constant modernization and urbanization of China,most cities have subways,and the total power consumption of subway stations has been rising,which contradicts with China’s green goals.In this regard,ener...Owing to the constant modernization and urbanization of China,most cities have subways,and the total power consumption of subway stations has been rising,which contradicts with China’s green goals.In this regard,energy consumption indicators for major energy use projects in subway stations should be established,comprehensive evaluation and detailed research on the current situation of subway operation should be conducted,and specific energy-saving measures should be taken from a diversified perspective.It is crucial to systematically sort out the principle of sub-item energy consumption in subway stations,and practice and explore the specific simplification measures of the principle model of sub-item energy consumption,so as to lay a solid foundation for achieving the goal of reducing energy consumption of subway stations.展开更多
Bioceramics have attracted extensive attention for bone defect repair due to their excellent bioactivity and degradability.However,challenges remain in matching the rate between bioceramic degradation and new bone for...Bioceramics have attracted extensive attention for bone defect repair due to their excellent bioactivity and degradability.However,challenges remain in matching the rate between bioceramic degradation and new bone formation,necessitating a deeper understanding of their degradation properties.In this study,density functional theory(DFT)calculations was employed to explore the structural and electronic characteristics of silicate bioceramics.These findings reveal a linear correlation between the maximum isosurface value of the valence band maximum(VBM_(Fmax))and the degradability of silicate bioceramics.This correlation was subsequently validated through degradation experiments.Furthermore,the investigation on phosphate bioceramics demonstrates the potential of this descriptor in predicting the degradability of a broader range of bioceramics.This discovery offers valuable insights into the degradation mechanism of bioceramics and holds promise for accelerating the design and development of bioceramics with controllable degradation.展开更多
With the increasing spotlight in electric vehicles,there is a growing demand for high-energy-density batteries to enhance driving range.Consequently,several studies have been conducted on high-energy-density LiNi_(x)C...With the increasing spotlight in electric vehicles,there is a growing demand for high-energy-density batteries to enhance driving range.Consequently,several studies have been conducted on high-energy-density LiNi_(x)Co_(y)Mn_(z)O_(2)cathodes.However,there is a limit to permanent performance deterioration because of side reactions caused by moisture in the atmosphere and continuous microcracks during cycling as the Ni content to express high energy increases and the content of Mn and Co that maintain structural and electrochemical stabilization decreases.The direct modification of the surface and bulk regions aims to enhance the capacity and long-term performance of high-Ni cathode materials.Therefore,an efficient modification requires a study based on a thorough understanding of the degradation mechanisms in the surface and bulk region.In this review,a comprehensive analysis of various modifications,including doping,coating,concentration gradient,and single crystals,is conducted to solve degradation issues along with an analysis of the overall degradation mechanism occurring in high-Ni cathode materials.It also summarizes recent research developments related to the following modifications,aims to provide notable points and directions for post-studies,and provides valuable references for the commercialization of stable high-energy-density cathode materials.展开更多
The spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)cathode active materials(CAMs)are considered a promising alternative to commercially available cathodes such as layered and polyanion oxide cathodes,primarily due to their notab...The spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)cathode active materials(CAMs)are considered a promising alternative to commercially available cathodes such as layered and polyanion oxide cathodes,primarily due to their notable safety and high energy density,particularly in their single-crystal type.Nevertheless,the industrial application of the LNMO CAMs is severely inhibited due to the interfacial deterioration and corrosion under proton-rich and high-voltage conditions.This study successfully designed and synthesized two typical types of crystal facets-exposed single-crystal LNMO CAMs.By tracking the electrochemical deterioration and chemical corrosion evolution,this study elucidates the surface degradation mechanisms and intrinsic instability of the LNMO,contingent upon their crystal facets.The(111)facet,due to its elevated surface energy,is found to be more susceptible to external attack compared to the(100)and(110)facets.Our study highlights the electrochemical corrosion stability of crystal plane engineering for spinel LNMO CAMs.展开更多
The fluid-solid coupling theory, an interdisciplinary science between hydrodynamics and solid mechanics, is an important tool for response analysis and direct design of structures in naval architecture and ocean engin...The fluid-solid coupling theory, an interdisciplinary science between hydrodynamics and solid mechanics, is an important tool for response analysis and direct design of structures in naval architecture and ocean engineering. By applying the corresponding relations between generalized forces and generalized displacements, convolutions were performed between the basic equations of elasto-dynamics in the primary space and corresponding virtual quantities. The results were integrated and then added algebraically. In light of the fact that body forces and surface forces are both follower forces, the generalized quasi-complementary energy principle with two kinds of variables for an initial value problem is established in non-conservative systems. Using the generalized quasi-complementary energy principle to deal with the fluid-solid coupling problem and to analyze the dynamic response of structures, a method for using two kinds of variables simultaneously for calculation of force and displacement was derived.展开更多
Magnesium and its alloys have such advantages with lightweight, high specific strength, good damping, high castability and machinability,which make them an attractive choice for applications where weight reduction is ...Magnesium and its alloys have such advantages with lightweight, high specific strength, good damping, high castability and machinability,which make them an attractive choice for applications where weight reduction is important, such as in the aerospace and automotive industries.However, their practical applications are still limited because of their poor corrosion resistance, low high temperature strength and ambient formability. Based on such their property shortcomings, recently degradable magnesium alloys were developed for broadening their potential applications. Considering the degradable Mg alloys for medical applications were well reviewed, the present review put an emphasis on such degradable magnesium alloys for structural and functional applications, especially the applications in the environmental and energy fields. Their applications as fracture ball in fossil energy, sacrificial anode, washing ball, and as battery anodes, transient electronics, were summarized. The roles of alloying elements in magnesium and the design concept of such degradable magnesium alloys were discussed. The existing challenges for extending their future applications are explored.展开更多
Polybrominated diphenyl ethers(PBDEs)are a kind of serious pollutants in the ocean.Biodegradation is considered as an economical and safe way for PBDEs removal and reductive debromination dominates the initial pathway...Polybrominated diphenyl ethers(PBDEs)are a kind of serious pollutants in the ocean.Biodegradation is considered as an economical and safe way for PBDEs removal and reductive debromination dominates the initial pathway of anaerobic degradation.On the basis of experimental study,Octa-BDE 197,Hepta-BDE 183,Hexa-BDE 153,Penta-BDE 99 and Tetra-BDE 47 were selected as the initial degradation objects,and their debromination degradation were studied using density functional theory.The structures were optimized by Gaussian 09 program.Furthermore,the molecular orbitals and charge distribution were analyzed.All C-Br bond dissociation energies at different positions including ortho,meta and para bromine atoms were calculated and the sequence of debromination was obtained.There is a close relationship between molecular structure,charge,molecular orbital and C-Br bond.All PBDEs exhibited similar debromination pathways with preferential removal of meta and para bromines.展开更多
In this paper, an inequality satisfied by the vacuum energy density of the universe is derived using an indirect and heuristic procedure. The derivation is based on a proposed thought experiment, according to which an...In this paper, an inequality satisfied by the vacuum energy density of the universe is derived using an indirect and heuristic procedure. The derivation is based on a proposed thought experiment, according to which an electron is accelerated to a constant and relativistic speed at a distance L from a perfectly conducting plane. The charge of the electron is represented by a spherical charge distribution located within the Compton wavelength of the electron. Subsequently, the electron is incident on the perfect conductor giving rise to transition radiation. The energy associated with the transition radiation depends on the parameter L. It is shown that an inequality satisfied by the vacuum energy density will emerge when the length L is pushed to cosmological dimensions and the product of the radiated energy and the time duration of emission are constrained by Heisenberg’s uncertainty principle. The inequality derived is given by ρ<sub>Λ</sub> ≤ 9.9×10<sup>-9</sup>J/m<sup>3</sup> where ρ<sub>Λ </sub>is the vacuum energy density. This result is consistent with the measured value of the vacuum energy density, which is 0.538 × 10<sup>-9</sup>J/m. Since there is a direct relationship between the vacuum energy density and the Einstein’s cosmological constant, the inequality can be converted directly to that of the cosmological constant.展开更多
New principles of work and energy as well as power and energy rate with cross terms for polar and nonlocal polar continuum field theories were presented and from them all corresponding equations of motion and boundary...New principles of work and energy as well as power and energy rate with cross terms for polar and nonlocal polar continuum field theories were presented and from them all corresponding equations of motion and boundary conditions as well as complete equations of energy and energy rate with the help of generalized Piola's theorems were naturally derived in all and without any additional requirement. Finally, some new balance laws of energy and energy rate for generalized continuum mechanics were established. The new principles of work and energy as well as power and energy rate with cross terms presented in this paper are believed to be new and they have corrected the incompleteness of all existing corresponding principles and laws without cross terms in literatures of generalized continuum field theories.展开更多
Friedmann equation of cosmology is based on the field equations of general relativity. Its derivation is straight-forward once the Einstein’s field equations are given and the derivation is independent of quantum mec...Friedmann equation of cosmology is based on the field equations of general relativity. Its derivation is straight-forward once the Einstein’s field equations are given and the derivation is independent of quantum mechanics. In this paper, it is shown that the Friedmann equation pertinent to a homogeneous, isotropic and flat universe can also be obtained as a consequence of the energy balance in the expanding universe between the positive energy associated with vacuum and matter, and the negative gravitational energy. The results obtained here is a clear consequence of the fact that the surface area of the Hubble sphere is proportional to the total amount of information contained within it.展开更多
Energy methods and the principle of virtual work are commonly used for obtaining solutions of boundary value problems (BVPs) and initial value problems (IVPs) associated with homogeneous, isotropic and non-homogeneous...Energy methods and the principle of virtual work are commonly used for obtaining solutions of boundary value problems (BVPs) and initial value problems (IVPs) associated with homogeneous, isotropic and non-homogeneous, non-isotropic matter without using (or in the absence of) the mathematical models of the BVPs and the IVPs. These methods are also used for deriving mathematical models for BVPs and IVPs associated with isotropic, homogeneous as well as non-homogeneous, non-isotropic continuous matter. In energy methods when applied to IVPs, one constructs energy functional (<i>I</i>) consisting of kinetic energy, strain energy and the potential energy of loads. The first variation of this energy functional (<em>δI</em>) set to zero is a necessary condition for an extremum of <i>I</i>. In this approach one could use <i>δI</i> = 0 directly in constructing computational processes such as the finite element method or could derive Euler’s equations (differential or partial differential equations) from <i>δI</i> = 0, which is also satisfied by a solution obtained from <i>δI</i> = 0. The Euler’s equations obtained from <i>δI</i> = 0 indeed are the mathematical model associated with the energy functional <i>I</i>. In case of BVPs we follow the same approach except in this case, the energy functional <i>I</i> consists of strain energy and the potential energy of loads. In using the principle of virtual work for BVPs and the IVPs, we can also accomplish the same as described above using energy methods. In this paper we investigate consistency and validity of the mathematical models for isotropic, homogeneous and non-isotropic, non-homogeneous continuous matter for BVPs that are derived using energy functional consisting of strain energy and the potential energy of loads. Similar investigation is also presented for IVPs using energy functional consisting of kinetic energy, strain energy and the potential energy of loads. The computational approaches for BVPs and the IVPs designed using energy functional and principle of virtual work, their consistency and validity are also investigated. Classical continuum mechanics (CCM) principles <i>i.e.</i> conservation and balance laws of CCM with consistent constitutive theories and the elements of calculus of variations are employed in the investigations presented in this paper.展开更多
In this paper the conception of theoretical determine the relations between material experimental characteristics is presented. On the base of stress-strain relations for nonlinear elastic anisotropic material and geo...In this paper the conception of theoretical determine the relations between material experimental characteristics is presented. On the base of stress-strain relations for nonlinear elastic anisotropic material and geometrical interpretation of deformation state, the general form of strain energy density function was introduced. Using this function and variational methods the relations between material characteristics were achieved. All considerations are illustrated by a short theoretical example.展开更多
The aim of this paper is to establish new principles of power and energy rate of incremental type in generalized continuum mechanics BY combining new principles of virtual velocity and virtual angular velocity as well...The aim of this paper is to establish new principles of power and energy rate of incremental type in generalized continuum mechanics BY combining new principles of virtual velocity and virtual angular velocity as well as of virtual stress anti virtual couple stress with c ross terms of incremental rate type a new principle of power anti energy rate of incremental rate type with cross terms for micropolar continuum field theories is presented and from it all corresponding equations of motion and boundary conditions as well as power and energy rate equations of incremental rate type for micropolar and nonlocal micropolar continua with the help of generalized Piola's theorems in all and without any additional requirement are derived. Complete results for micromorphic continua could be similarly derived. The derived results in the present paper are believed to be new. They could be used to establish corresponding finite element methods of incremental rate type for generalized continuum mechanics.展开更多
A simulation method of dense particle-gas two-phase flow has been developed. The binding force is introduced to present the impact of particle clustering and its expression is deduced according to the principle of min...A simulation method of dense particle-gas two-phase flow has been developed. The binding force is introduced to present the impact of particle clustering and its expression is deduced according to the principle of minimal potential energy. The cluster collision, break-up and coalescence models are proposed based on the assumption that the particle cluster are treated as one discrete phase. These models are used to numerically study the two-phase flow field in a circulating fluidized bed (CFB). Detailed results of the cluster structure, cluster size, particle volume fraction, gas velocity, and particle velocity are obtained. The correlation between the simulation results and experimental data justifies that these models and algorithm are reasonable, and can be used to efficiently study the dense particle-gas two-phase flow.展开更多
Polystyrene (PS) waste plastic to renewable energy or naphtha grade fuel production through fractional distillation process was applied and PS liquefaction temperature range was 250?C - 430?C and fractional column tem...Polystyrene (PS) waste plastic to renewable energy or naphtha grade fuel production through fractional distillation process was applied and PS liquefaction temperature range was 250?C - 430?C and fractional column temperature was 110?C - 135?C for naphtha grade fuel separation. The thermal degradation of PS waste plastic to renewable energy or naphtha grade chemical production was without adding any kind of cracking catalyst and without vacuum system. Polystyrene waste plastic is not bio-degradable and its can remain long period of landfill and creating gas emission for that reason its major cause climate change. For experimental purpose raw sample was use 1 kg of PS waste plastic and experiment was performed under Labconco fume hood and experiment was fully closed system, whole experiment was performed into stainless steel reactor. Produced fuel was analysis by gas chromatography and mass spectrometer, FT-IR and DSC. Analysis result indicate for fuel compounds chemical structure, compound band energy and enthalpy, delta H value. Produced fuel sulfur content less then environmental protection agency (EPA) level and fuel could be use for chemical feedstock refinery for further modification. By using this technology can reduce some foreign oil dependency and boost up renewable energy sector all over the world.展开更多
An attempt is done to calculate the value of the elementary electron charge from its relation to the Planck constant and the speed of light. This relation is obtained, in the first step, from the Pauli analysis of the...An attempt is done to calculate the value of the elementary electron charge from its relation to the Planck constant and the speed of light. This relation is obtained, in the first step, from the Pauli analysis of the strength of the electric field associated with an elementary emission process of energy. In the next step, the uncertainty principle is applied to both the emission time and energy. The theoretical result for e is roughly close to the experimental value of the electron charge.展开更多
The paper provides a review and conciliation of the results pertinent to the energy and action associated with electromagnetic radiation obtained using classical electrodynamics and published in several journal papers...The paper provides a review and conciliation of the results pertinent to the energy and action associated with electromagnetic radiation obtained using classical electrodynamics and published in several journal papers. The results presented in those papers are based on three systems that generate electromagnetic radiation, namely, frequency domain antennas, time domain antennas and decelerating (or accelerating) charged elementary particles. In the case of radiation generated by a frequency domain antenna, the energy dissipated as radiation within half a period, U, satisfies the order of magnitude inequality U ≥ hv → q ≥ e where q is the magnitude of the oscillating charge in the antenna, e is the elementary charge, v is the frequency and h is the Planck constant. In the case of transient radiation fields generated by time domain antennas or the radiation emitted by decelerating (or accelerating) charged elementary particles, the energy dissipated by the system as radiation satisfies the order of magnitude inequality Uτr ≥ h/4π → q ≥ e where U is the energy dissipated as radiation by the system τr, is the duration of the energy emission and q is either the charge in the current pulse in the case of the time domain antenna or the charge of the elementary particle giving rise to the radiation. These results are derived while adhering strictly to the principles of classical electrodynamics alone. These results were interpreted in different papers in different ways using different assumptions. In this paper, we provide a unified interpretation of the results, and combining these results with two simple quantum mechanical concepts, expression for the elementary charge as a function of other natural constants and the energy density of vacuum is derived. The expressions predict the elementary charge to an accuracy higher than about 1%.展开更多
A modified uncertainty principle coupling the intervals of energy and time can lead to the shortest distance attained in course of the excitation process, as well as the shortest possible time interval for that proces...A modified uncertainty principle coupling the intervals of energy and time can lead to the shortest distance attained in course of the excitation process, as well as the shortest possible time interval for that process. These lower bounds are much similar to the interval limits deduced on both the experimental and theoretical footing in the era when the Heisenberg uncertainty principle has been developed. In effect of the bounds existence, a maximal nuclear charge Ze acceptable for the Bohr atomic ion could be calculated. In the next step the velocity of electron transitions between the Bohr orbits is found to be close to the speed of light. This result provides us with the energy spectrum of transitions similar to that obtained in the Bohr’s model. A momentary force acting on the electrons in course of their transitions is estimated to be by many orders larger than a steady electrostatic force existent between the atomic electron and the nucleus.展开更多
The De Broglie’s approach to the quantum theory, when combined with the conservation rule of momentum, allows one to calculate the velocity of the electron transition from a quantum state n to its neighbouring state ...The De Broglie’s approach to the quantum theory, when combined with the conservation rule of momentum, allows one to calculate the velocity of the electron transition from a quantum state n to its neighbouring state as a function of n. The paper shows, for the case of the harmonic oscillator taken as an example, that the De Broglie’s dependence of the transition velocity on n is equal to the n-dependence of that velocity calculated with the aid of the uncertainty principle for the energy and time. In the next step the minimal distance parameter provided by the uncertainty principle is applied in calculating the magnetic moment of the electron which effectuates its orbital motion in the magnetic field. This application gives readily the electron spin magnetic moment as well as the quantum of the magnetic flux known in superconductors as its result.展开更多
文摘In Part I of this paper, an inequality satisfied by the vacuum energy density of the universe was derived using an indirect and heuristic procedure. The derivation is based on a proposed thought experiment, according to which an electron is accelerated to a constant and relativistic speed at a distance L from a perfectly conducting plane. The charge of the electron was represented by a spherical charge distribution located within the Compton wavelength of the electron. Subsequently, the electron is incident on the perfect conductor giving rise to transition radiation. The energy associated with the transition radiation depends on the parameter L. It was shown that an inequality satisfied by the vacuum energy density will emerge when the length L is pushed to cosmological dimensions and the product of the radiated energy, and the time duration of emission is constrained by Heisenberg’s uncertainty principle. In this paper, a similar analysis is conducted with a chain of electrons oscillating sinusoidally and located above a conducting plane. In the thought experiment presented in this paper, the behavior of the energy radiated by the chain of oscillating electrons is studied in the frequency domain as a function of the length L of the chain. It is shown that when the length L is pushed to cosmological dimensions and the energy radiated within a single burst of duration of half a period of oscillation is constrained by the fact that electromagnetic energy consists of photons, an inequality satisfied by the vacuum energy density emerges as a result. The derived inequality is given by where is the vacuum energy density. This result is consistent with the measured value of the vacuum energy density, which is 5.38 × 10<sup>-10</sup> J/m. The result obtained here is in better agreement with experimental data than the one obtained in Part I of this paper with time domain radiation.
文摘Owing to the constant modernization and urbanization of China,most cities have subways,and the total power consumption of subway stations has been rising,which contradicts with China’s green goals.In this regard,energy consumption indicators for major energy use projects in subway stations should be established,comprehensive evaluation and detailed research on the current situation of subway operation should be conducted,and specific energy-saving measures should be taken from a diversified perspective.It is crucial to systematically sort out the principle of sub-item energy consumption in subway stations,and practice and explore the specific simplification measures of the principle model of sub-item energy consumption,so as to lay a solid foundation for achieving the goal of reducing energy consumption of subway stations.
基金National Key Research and Development Program of China (2023YFB3813000)National Natural Science Foundation of China (52272256)State Key Laboratory of Advanced Technology for Materials Synthesis and Processing (Wuhan University of Technology)(2022-KF-77)。
文摘Bioceramics have attracted extensive attention for bone defect repair due to their excellent bioactivity and degradability.However,challenges remain in matching the rate between bioceramic degradation and new bone formation,necessitating a deeper understanding of their degradation properties.In this study,density functional theory(DFT)calculations was employed to explore the structural and electronic characteristics of silicate bioceramics.These findings reveal a linear correlation between the maximum isosurface value of the valence band maximum(VBM_(Fmax))and the degradability of silicate bioceramics.This correlation was subsequently validated through degradation experiments.Furthermore,the investigation on phosphate bioceramics demonstrates the potential of this descriptor in predicting the degradability of a broader range of bioceramics.This discovery offers valuable insights into the degradation mechanism of bioceramics and holds promise for accelerating the design and development of bioceramics with controllable degradation.
文摘With the increasing spotlight in electric vehicles,there is a growing demand for high-energy-density batteries to enhance driving range.Consequently,several studies have been conducted on high-energy-density LiNi_(x)Co_(y)Mn_(z)O_(2)cathodes.However,there is a limit to permanent performance deterioration because of side reactions caused by moisture in the atmosphere and continuous microcracks during cycling as the Ni content to express high energy increases and the content of Mn and Co that maintain structural and electrochemical stabilization decreases.The direct modification of the surface and bulk regions aims to enhance the capacity and long-term performance of high-Ni cathode materials.Therefore,an efficient modification requires a study based on a thorough understanding of the degradation mechanisms in the surface and bulk region.In this review,a comprehensive analysis of various modifications,including doping,coating,concentration gradient,and single crystals,is conducted to solve degradation issues along with an analysis of the overall degradation mechanism occurring in high-Ni cathode materials.It also summarizes recent research developments related to the following modifications,aims to provide notable points and directions for post-studies,and provides valuable references for the commercialization of stable high-energy-density cathode materials.
基金supported by the National Natural Science Foundation of China (52374311)the National Natural Science Foundation of Shaanxi (2022KXJ-146)+3 种基金the Fundamental Research Funds for the Central Universities (D5000230091)Open project of Shaanxi Laboratory of Aerospace Power (2022ZY2-JCYJ-01-09)full-depth-sea battery project (No.2020-XXXX-XX-246-00)the Youth Innovation Team of Shaanxi Universities。
文摘The spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)cathode active materials(CAMs)are considered a promising alternative to commercially available cathodes such as layered and polyanion oxide cathodes,primarily due to their notable safety and high energy density,particularly in their single-crystal type.Nevertheless,the industrial application of the LNMO CAMs is severely inhibited due to the interfacial deterioration and corrosion under proton-rich and high-voltage conditions.This study successfully designed and synthesized two typical types of crystal facets-exposed single-crystal LNMO CAMs.By tracking the electrochemical deterioration and chemical corrosion evolution,this study elucidates the surface degradation mechanisms and intrinsic instability of the LNMO,contingent upon their crystal facets.The(111)facet,due to its elevated surface energy,is found to be more susceptible to external attack compared to the(100)and(110)facets.Our study highlights the electrochemical corrosion stability of crystal plane engineering for spinel LNMO CAMs.
基金Supported by the National Natural Science Foundation under Grant No.10272034the Doctoral Education Foundation under Grant No.20060217020
文摘The fluid-solid coupling theory, an interdisciplinary science between hydrodynamics and solid mechanics, is an important tool for response analysis and direct design of structures in naval architecture and ocean engineering. By applying the corresponding relations between generalized forces and generalized displacements, convolutions were performed between the basic equations of elasto-dynamics in the primary space and corresponding virtual quantities. The results were integrated and then added algebraically. In light of the fact that body forces and surface forces are both follower forces, the generalized quasi-complementary energy principle with two kinds of variables for an initial value problem is established in non-conservative systems. Using the generalized quasi-complementary energy principle to deal with the fluid-solid coupling problem and to analyze the dynamic response of structures, a method for using two kinds of variables simultaneously for calculation of force and displacement was derived.
文摘Magnesium and its alloys have such advantages with lightweight, high specific strength, good damping, high castability and machinability,which make them an attractive choice for applications where weight reduction is important, such as in the aerospace and automotive industries.However, their practical applications are still limited because of their poor corrosion resistance, low high temperature strength and ambient formability. Based on such their property shortcomings, recently degradable magnesium alloys were developed for broadening their potential applications. Considering the degradable Mg alloys for medical applications were well reviewed, the present review put an emphasis on such degradable magnesium alloys for structural and functional applications, especially the applications in the environmental and energy fields. Their applications as fracture ball in fossil energy, sacrificial anode, washing ball, and as battery anodes, transient electronics, were summarized. The roles of alloying elements in magnesium and the design concept of such degradable magnesium alloys were discussed. The existing challenges for extending their future applications are explored.
基金the National Natural Science Foundation of China(Nos.41406090,42176045)the Science Foundation of Qingdao Agricultural University(No.631302)+1 种基金the Fujian Key Laboratory of Functional Marine Sensing Materials,Minjiang University(No.MJUKF-FMSM202102)the Natural Science Foundation of Shandong Province(Nos.ZR2019 MB020,ZR2020MB119)。
文摘Polybrominated diphenyl ethers(PBDEs)are a kind of serious pollutants in the ocean.Biodegradation is considered as an economical and safe way for PBDEs removal and reductive debromination dominates the initial pathway of anaerobic degradation.On the basis of experimental study,Octa-BDE 197,Hepta-BDE 183,Hexa-BDE 153,Penta-BDE 99 and Tetra-BDE 47 were selected as the initial degradation objects,and their debromination degradation were studied using density functional theory.The structures were optimized by Gaussian 09 program.Furthermore,the molecular orbitals and charge distribution were analyzed.All C-Br bond dissociation energies at different positions including ortho,meta and para bromine atoms were calculated and the sequence of debromination was obtained.There is a close relationship between molecular structure,charge,molecular orbital and C-Br bond.All PBDEs exhibited similar debromination pathways with preferential removal of meta and para bromines.
文摘In this paper, an inequality satisfied by the vacuum energy density of the universe is derived using an indirect and heuristic procedure. The derivation is based on a proposed thought experiment, according to which an electron is accelerated to a constant and relativistic speed at a distance L from a perfectly conducting plane. The charge of the electron is represented by a spherical charge distribution located within the Compton wavelength of the electron. Subsequently, the electron is incident on the perfect conductor giving rise to transition radiation. The energy associated with the transition radiation depends on the parameter L. It is shown that an inequality satisfied by the vacuum energy density will emerge when the length L is pushed to cosmological dimensions and the product of the radiated energy and the time duration of emission are constrained by Heisenberg’s uncertainty principle. The inequality derived is given by ρ<sub>Λ</sub> ≤ 9.9×10<sup>-9</sup>J/m<sup>3</sup> where ρ<sub>Λ </sub>is the vacuum energy density. This result is consistent with the measured value of the vacuum energy density, which is 0.538 × 10<sup>-9</sup>J/m. Since there is a direct relationship between the vacuum energy density and the Einstein’s cosmological constant, the inequality can be converted directly to that of the cosmological constant.
文摘New principles of work and energy as well as power and energy rate with cross terms for polar and nonlocal polar continuum field theories were presented and from them all corresponding equations of motion and boundary conditions as well as complete equations of energy and energy rate with the help of generalized Piola's theorems were naturally derived in all and without any additional requirement. Finally, some new balance laws of energy and energy rate for generalized continuum mechanics were established. The new principles of work and energy as well as power and energy rate with cross terms presented in this paper are believed to be new and they have corrected the incompleteness of all existing corresponding principles and laws without cross terms in literatures of generalized continuum field theories.
文摘Friedmann equation of cosmology is based on the field equations of general relativity. Its derivation is straight-forward once the Einstein’s field equations are given and the derivation is independent of quantum mechanics. In this paper, it is shown that the Friedmann equation pertinent to a homogeneous, isotropic and flat universe can also be obtained as a consequence of the energy balance in the expanding universe between the positive energy associated with vacuum and matter, and the negative gravitational energy. The results obtained here is a clear consequence of the fact that the surface area of the Hubble sphere is proportional to the total amount of information contained within it.
文摘Energy methods and the principle of virtual work are commonly used for obtaining solutions of boundary value problems (BVPs) and initial value problems (IVPs) associated with homogeneous, isotropic and non-homogeneous, non-isotropic matter without using (or in the absence of) the mathematical models of the BVPs and the IVPs. These methods are also used for deriving mathematical models for BVPs and IVPs associated with isotropic, homogeneous as well as non-homogeneous, non-isotropic continuous matter. In energy methods when applied to IVPs, one constructs energy functional (<i>I</i>) consisting of kinetic energy, strain energy and the potential energy of loads. The first variation of this energy functional (<em>δI</em>) set to zero is a necessary condition for an extremum of <i>I</i>. In this approach one could use <i>δI</i> = 0 directly in constructing computational processes such as the finite element method or could derive Euler’s equations (differential or partial differential equations) from <i>δI</i> = 0, which is also satisfied by a solution obtained from <i>δI</i> = 0. The Euler’s equations obtained from <i>δI</i> = 0 indeed are the mathematical model associated with the energy functional <i>I</i>. In case of BVPs we follow the same approach except in this case, the energy functional <i>I</i> consists of strain energy and the potential energy of loads. In using the principle of virtual work for BVPs and the IVPs, we can also accomplish the same as described above using energy methods. In this paper we investigate consistency and validity of the mathematical models for isotropic, homogeneous and non-isotropic, non-homogeneous continuous matter for BVPs that are derived using energy functional consisting of strain energy and the potential energy of loads. Similar investigation is also presented for IVPs using energy functional consisting of kinetic energy, strain energy and the potential energy of loads. The computational approaches for BVPs and the IVPs designed using energy functional and principle of virtual work, their consistency and validity are also investigated. Classical continuum mechanics (CCM) principles <i>i.e.</i> conservation and balance laws of CCM with consistent constitutive theories and the elements of calculus of variations are employed in the investigations presented in this paper.
文摘In this paper the conception of theoretical determine the relations between material experimental characteristics is presented. On the base of stress-strain relations for nonlinear elastic anisotropic material and geometrical interpretation of deformation state, the general form of strain energy density function was introduced. Using this function and variational methods the relations between material characteristics were achieved. All considerations are illustrated by a short theoretical example.
文摘The aim of this paper is to establish new principles of power and energy rate of incremental type in generalized continuum mechanics BY combining new principles of virtual velocity and virtual angular velocity as well as of virtual stress anti virtual couple stress with c ross terms of incremental rate type a new principle of power anti energy rate of incremental rate type with cross terms for micropolar continuum field theories is presented and from it all corresponding equations of motion and boundary conditions as well as power and energy rate equations of incremental rate type for micropolar and nonlocal micropolar continua with the help of generalized Piola's theorems in all and without any additional requirement are derived. Complete results for micromorphic continua could be similarly derived. The derived results in the present paper are believed to be new. They could be used to establish corresponding finite element methods of incremental rate type for generalized continuum mechanics.
基金This work was financially supported by the National Natural Science Foundation of China (No.50406025).
文摘A simulation method of dense particle-gas two-phase flow has been developed. The binding force is introduced to present the impact of particle clustering and its expression is deduced according to the principle of minimal potential energy. The cluster collision, break-up and coalescence models are proposed based on the assumption that the particle cluster are treated as one discrete phase. These models are used to numerically study the two-phase flow field in a circulating fluidized bed (CFB). Detailed results of the cluster structure, cluster size, particle volume fraction, gas velocity, and particle velocity are obtained. The correlation between the simulation results and experimental data justifies that these models and algorithm are reasonable, and can be used to efficiently study the dense particle-gas two-phase flow.
文摘Polystyrene (PS) waste plastic to renewable energy or naphtha grade fuel production through fractional distillation process was applied and PS liquefaction temperature range was 250?C - 430?C and fractional column temperature was 110?C - 135?C for naphtha grade fuel separation. The thermal degradation of PS waste plastic to renewable energy or naphtha grade chemical production was without adding any kind of cracking catalyst and without vacuum system. Polystyrene waste plastic is not bio-degradable and its can remain long period of landfill and creating gas emission for that reason its major cause climate change. For experimental purpose raw sample was use 1 kg of PS waste plastic and experiment was performed under Labconco fume hood and experiment was fully closed system, whole experiment was performed into stainless steel reactor. Produced fuel was analysis by gas chromatography and mass spectrometer, FT-IR and DSC. Analysis result indicate for fuel compounds chemical structure, compound band energy and enthalpy, delta H value. Produced fuel sulfur content less then environmental protection agency (EPA) level and fuel could be use for chemical feedstock refinery for further modification. By using this technology can reduce some foreign oil dependency and boost up renewable energy sector all over the world.
文摘An attempt is done to calculate the value of the elementary electron charge from its relation to the Planck constant and the speed of light. This relation is obtained, in the first step, from the Pauli analysis of the strength of the electric field associated with an elementary emission process of energy. In the next step, the uncertainty principle is applied to both the emission time and energy. The theoretical result for e is roughly close to the experimental value of the electron charge.
文摘The paper provides a review and conciliation of the results pertinent to the energy and action associated with electromagnetic radiation obtained using classical electrodynamics and published in several journal papers. The results presented in those papers are based on three systems that generate electromagnetic radiation, namely, frequency domain antennas, time domain antennas and decelerating (or accelerating) charged elementary particles. In the case of radiation generated by a frequency domain antenna, the energy dissipated as radiation within half a period, U, satisfies the order of magnitude inequality U ≥ hv → q ≥ e where q is the magnitude of the oscillating charge in the antenna, e is the elementary charge, v is the frequency and h is the Planck constant. In the case of transient radiation fields generated by time domain antennas or the radiation emitted by decelerating (or accelerating) charged elementary particles, the energy dissipated by the system as radiation satisfies the order of magnitude inequality Uτr ≥ h/4π → q ≥ e where U is the energy dissipated as radiation by the system τr, is the duration of the energy emission and q is either the charge in the current pulse in the case of the time domain antenna or the charge of the elementary particle giving rise to the radiation. These results are derived while adhering strictly to the principles of classical electrodynamics alone. These results were interpreted in different papers in different ways using different assumptions. In this paper, we provide a unified interpretation of the results, and combining these results with two simple quantum mechanical concepts, expression for the elementary charge as a function of other natural constants and the energy density of vacuum is derived. The expressions predict the elementary charge to an accuracy higher than about 1%.
文摘A modified uncertainty principle coupling the intervals of energy and time can lead to the shortest distance attained in course of the excitation process, as well as the shortest possible time interval for that process. These lower bounds are much similar to the interval limits deduced on both the experimental and theoretical footing in the era when the Heisenberg uncertainty principle has been developed. In effect of the bounds existence, a maximal nuclear charge Ze acceptable for the Bohr atomic ion could be calculated. In the next step the velocity of electron transitions between the Bohr orbits is found to be close to the speed of light. This result provides us with the energy spectrum of transitions similar to that obtained in the Bohr’s model. A momentary force acting on the electrons in course of their transitions is estimated to be by many orders larger than a steady electrostatic force existent between the atomic electron and the nucleus.
文摘The De Broglie’s approach to the quantum theory, when combined with the conservation rule of momentum, allows one to calculate the velocity of the electron transition from a quantum state n to its neighbouring state as a function of n. The paper shows, for the case of the harmonic oscillator taken as an example, that the De Broglie’s dependence of the transition velocity on n is equal to the n-dependence of that velocity calculated with the aid of the uncertainty principle for the energy and time. In the next step the minimal distance parameter provided by the uncertainty principle is applied in calculating the magnetic moment of the electron which effectuates its orbital motion in the magnetic field. This application gives readily the electron spin magnetic moment as well as the quantum of the magnetic flux known in superconductors as its result.