This paper aims to investigate the multi-soliton solutions of the coupled Lakshmanan–Porsezian–Daniel equations with variable coefficients under nonzero boundary conditions.These equations are utilized to model the ...This paper aims to investigate the multi-soliton solutions of the coupled Lakshmanan–Porsezian–Daniel equations with variable coefficients under nonzero boundary conditions.These equations are utilized to model the phenomenon of nonlinear waves propagating simultaneously in non-uniform optical fibers.By analyzing the Lax pair and the Riemann–Hilbert problem,we aim to provide a comprehensive understanding of the dynamics and interactions of solitons of this system.Furthermore,we study the impacts of group velocity dispersion or the fourth-order dispersion on soliton behaviors.Through appropriate parameter selections,we observe various nonlinear phenomena,including the disappearance of solitons after interaction and their transformation into breather-like solitons,as well as the propagation of breathers with variable periodicity and interactions between solitons with variable periodicities.展开更多
The dynamic vibration absorber with inerter and grounded stiffness(IGDVA)is used to control a two-scale system subject to a weak periodic perturbation.The vibration suppression effect is remarkable.The amplitude of th...The dynamic vibration absorber with inerter and grounded stiffness(IGDVA)is used to control a two-scale system subject to a weak periodic perturbation.The vibration suppression effect is remarkable.The amplitude of the main system coupled with absorber is significantly reduced,and the high frequency vibration completely disappears.First,through the slow-fast analysis and stability theory,it is found that the stability of the autonomous system exerts a notable regulating effect on the vibration response of the non-autonomous system.After adding the dynamic vibrator absorber,the center in the autonomous system changes to an asymptotically stable focus,consequently suppressing the vibration in the non-autonomous system.Further research reveals that the parameters of the absorber affect the real parts of the eigenvalues of the autonomous system,thereby regulating the stability of the system.Transitioning from a qualitative standpoint to a quantitative approach,a comparison of the solutions before and after the introduction of the dynamic absorber reveals that,when the grounded stiffness ratio and the mass ratio of the dynamic absorber are not equal,the high-frequency part in the analytical solution disappears.As a result,this leads to a reduction in the amplitude of the trajectory,achieving a vibration reduction effect.展开更多
Combining the mean field Pozhar-Gubbins(PG)theory and the weighted density approximation,a novel method for local thermal conductivity of inhomogeneous fluids is proposed.The correlation effect that is beyond the mean...Combining the mean field Pozhar-Gubbins(PG)theory and the weighted density approximation,a novel method for local thermal conductivity of inhomogeneous fluids is proposed.The correlation effect that is beyond the mean field treatment is taken into account by the simulation-based empirical correlations.The application of this method to confined argon in slit pore shows that its prediction agrees well with the simulation results,and that it performs better than the original PG theory as well as the local averaged density model(LADM).In its further application to the nano-fluidic films,the influences of fluid parameters and pore parameters on the thermal conductivity are calculated and investigated.It is found that both the local thermal conductivity and the overall thermal conductivity can be significantly modulated by these parameters.Specifically,in the supercritical states,the thermal conductivity of the confined fluid shows positive correlation to the bulk density as well as the temperature.However,when the bulk density is small,the thermal conductivity exhibits a decrease-increase transition as the temperature is increased.This is also the case in which the temperature is low.In fact,the decrease-increase transition in both the small-bulk-density and low-temperature cases arises from the capillary condensation in the pore.Furthermore,smaller pore width and/or stronger adsorption potential can raise the critical temperature for condensation,and then are beneficial to the enhancement of the thermal conductivity.These modulation behaviors of the local thermal conductivity lead immediately to the significant difference of the overall thermal conductivity in different phase regions.展开更多
A program developed with COMSOL software integrates EAST four-strap antenna coupling with the double-stub Ferrite tuners(FT)impedance matching,obtaining physical quantities crucial for predicting the overall performan...A program developed with COMSOL software integrates EAST four-strap antenna coupling with the double-stub Ferrite tuners(FT)impedance matching,obtaining physical quantities crucial for predicting the overall performance of the ion cyclotron resonance heating(ICRH)antenna and matching system.These quantities encompass S-matrix,port complex impedance,reflection coefficients,electric field and voltage distribution,and optimal matching settings.In this study,we explore the relationship between S-matrix,reflection coefficients,port complex impedance,and frequency.Then,we analyze the impact of Faraday screens placement position and transparency,the distance from the Faraday screen(FS)to the current straps(CS),the relative distance between ports,and the characteristic impedance of the transmission line on the coupling characteristic impedance of the EAST ICRH system.Finally,we simulate the electric field distribution and voltage distribution of the EAST ICRH system for plasma heating with double-stub FT impedance matching.Using optimized parameters,the coupling power of the ICRH system can be approximately doubled.The results present herein may offer guidance for the design of high-power,long-pulse operation ICRH antenna systems.展开更多
This paper models the giraffe’s jugular veins as a uniform collapsible tube from a rigid skull. The equations governing one-dimensional steady flow through such a tube for various conditions have been developed. The ...This paper models the giraffe’s jugular veins as a uniform collapsible tube from a rigid skull. The equations governing one-dimensional steady flow through such a tube for various conditions have been developed. The effects of inertial and inclination angles that have not been discussed previously have been included. It has been shown that different flows for a uniform tube (vein) are possible. However, this flow matches that of a jugular vein which is supercritical, and the steady solution has been given by the balance between the driving forces of gravity and the viscous resistance to the flow at the right atrium of the heart must be sub-critical for a fixed right-atrium pressure which means that an elastic jump is required to return the flow to sub-critical from the supercritical flow upstream this type of relationship gives rise to flow limitation at the same time given any right atrium fixed pressure there exists a maximum flow rate which when exceeded the boundary conditions of the flow do not hold boundary conditions at the right atrium are not satisfied hence making the steady flow impossible this mechanism of flow limitation is slightly different from the other one in that causes airways through forced expiration from the observation made it is clearly shown that there is an intravascular pressure difference with a change in height.展开更多
In recent years, there has been remarkable progress in the performance of metal halide perovskite solar cells. Studies have shown significant interest in lead-free perovskite solar cells (PSCs) due to concerns about t...In recent years, there has been remarkable progress in the performance of metal halide perovskite solar cells. Studies have shown significant interest in lead-free perovskite solar cells (PSCs) due to concerns about the toxicity of lead in lead halide perovskites. CH3NH3SnI3 emerges as a viable alternative to CH3NH3PbX3. In this work, we studied the effect of various parameters on the performance of lead-free perovskite solar cells using simulation with the SCAPS 1D software. The cell structure consists of α-Fe2O3/CH3NH3SnI3/PEDOT: PSS. We analyzed parameters such as thickness, doping, and layer concentration. The study revealed that, without considering other optimized parameters, the efficiency of the cell increased from 22% to 35% when the perovskite thickness varied from 100 to 1000 nm. After optimization, solar cell efficiency reaches up to 42%. The optimization parameters are such that, for example, for perovskite: the layer thickness is 700 nm, the doping concentration is 1020 and the defect density is 1013 cm−3, and for hematite: the thickness is 5 nm, the doping concentration is 1022 and the defect concentration is 1011 cm−3. These results are encouraging because they highlight the good agreement between perovskite and hematite when used as the active and electron transport layers, respectively. Now, it is still necessary to produce real, viable photovoltaic solar cells with the proposed material layer parameters.展开更多
The dynamically shifted oscillator is investigated quantum mechanically, both analytically and numerically. It is shown that the commonly used method of solving the Schrödinger equation using power series results...The dynamically shifted oscillator is investigated quantum mechanically, both analytically and numerically. It is shown that the commonly used method of solving the Schrödinger equation using power series results in incorrect eigenvalues and eigenfunctions.展开更多
The application potential of cellulosic materials in natural composites and other fields needs to be explored to develop innovative, sustainable, lightweight, functional biomass materials that are also environmentally...The application potential of cellulosic materials in natural composites and other fields needs to be explored to develop innovative, sustainable, lightweight, functional biomass materials that are also environmentally friendly. This study investigated Typha angustifolia (Typha sp.) as a potential new raw material for extracting cellulose nanocrystals (CNCs) for application in wastewater treatment composites. Alkaline treatments and bleaching were used to remove cellulose from the stem fibres. The CNCs were then isolated from the recovered cellulose using acid hydrolysis. The study showed a few distinct functional groups (O-H, -C-H, =C-H and C-O, and C-O-C) in the Fourier Transform Infrared (FTIR) spectra. A scanning electron microscope (SEM) revealed the smooth surface of CPC and CNCs, which resulted from removing lignin and hemicellulose from powdered Typha angustifolia. Based on the crystalline index, the powdered Typha angustifolia, CPC, and CNCs were 42.86%, 66.94% and 77.41%. The loss of the amorphous section of the Typha sp. fibre resulted in a decrease in particle size. It may be inferred from the features of a Typha sp. CNC that CNCs may be employed as reinforcement in composites for wastewater treatment.展开更多
We show that an intrinsically nonlinear oscillator can always be transformed into a linear or harmonic oscillator by addition of a constant force, which shifts the equilibrium position of the oscillator.
This article examines the dynamics for stochastic plate equations with linear memory in the case of bounded domain. We investigate the existence of solutions and bounded absorbing set by using the uniform pullback att...This article examines the dynamics for stochastic plate equations with linear memory in the case of bounded domain. We investigate the existence of solutions and bounded absorbing set by using the uniform pullback attractors on the tails estimates, and the asymptotic compactness of the random dynamical system is proved by decomposition method, and then we obtain the existence of a random attractor.展开更多
The simulation by the Monte Carlo method executed by the software PyPENELOPE proved effective to specify the particle propagation characteristics by calculating the absorption fractions, backscattering and transmissio...The simulation by the Monte Carlo method executed by the software PyPENELOPE proved effective to specify the particle propagation characteristics by calculating the absorption fractions, backscattering and transmission of electrons and secondary photons under the incidence of 0.5 to 20 KeV range of primary electrons. More than 99.9% of the primary electrons were transmitted in the 125 nm thick MgO/TiO<sub>2</sub> material at 20 KeV. This occurred because several interactions took place in the transmitted primary irradiation such as characteristic, fluorescence, and bremsstrahlung produced when of the occupation of the KL3, KL2, KM3, and KM2 shell and sub-shell of titanium and magnesium which are the elements with a high atomic number in the material. The transmission particle characteristic of this material is therefore an indicator capable of improving the electrical performance and properties of the sensor.展开更多
We study the strong nonlinear optical dynamics of nanosecond pulsed Laguerre–Gaussian laser beams of high-order radial modes with zero orbital angular momentum propagating in the fullerene C60molecular medium. It is ...We study the strong nonlinear optical dynamics of nanosecond pulsed Laguerre–Gaussian laser beams of high-order radial modes with zero orbital angular momentum propagating in the fullerene C60molecular medium. It is found that the spatiotemporal profile of the incident pulsed Laguerre–Gaussian laser beam is strongly reshaped during its propagation in the C60molecular medium. The centrosymmetric temporal profile of the incident pulse gradually evolves into a noncentrosymmetric meniscus shape, and the on-axis pulse duration is clearly depressed. Furthermore, the field intensity is distinctly attenuated due to the field-intensity-dependent reverse saturable absorption, and clear optical power limiting behavior is observed for different orders of the input pulsed Laguerre–Gaussian laser beams before the takeover of the saturation effect;the lower the order of the Laguerre–Gaussian beam, the lower the energy transmittance.展开更多
The origins of superconductivity and pairing symmetry of order parameters are still controversial problems for FeSe thin films up to date.Under the Neumann boundary conditions,the electromagnetic properties of this sy...The origins of superconductivity and pairing symmetry of order parameters are still controversial problems for FeSe thin films up to date.Under the Neumann boundary conditions,the electromagnetic properties of this system are investigated using the two-band Ginzburg-Landau theory.We calculate the temperature dependence of upper critical field in arbitrary direction and critical supercurrent density through the FeSe film.It is revealed that the normalized upper critical field is independent of the film thickness and all of our theoretical results are in accordance with the experimental data.These thus strongly indicate the existence of two-gap s-wave superconductivity in this material.展开更多
A continuum theoretical scheme for self-rolling nanotubes from bilayers by mismatch is obtained by considering surface elasticity,surface stress,and symmetry lowering effects.For an ultrathin nanofilm with only severa...A continuum theoretical scheme for self-rolling nanotubes from bilayers by mismatch is obtained by considering surface elasticity,surface stress,and symmetry lowering effects.For an ultrathin nanofilm with only several nanometers in thickness,isotropic mismatch,and isotropic surface stress usually induce anisotropic rolling behavior.The isotropic Timoshenko formula should be modified anisotropically to explain the mechanical behavior of anisotropic rolling structure of nanotubes accurately.The nanofilm rolls up in tangential direction while remaining straight in cylindrical direction theoretically.Therefore,in this paper the anisotropic shape of nanotubes is taken into consideration.Along the cylindrical direction,although it maintains straight and its residual strain is uniform,the stress varies in the radial direction due to the Poisson's effect of tangential strain.The results of the current theory applied to Si-Si nanotube,InAs-GaAs nanotube,and InGaAs-Cr nanotube systems show good agreement with the experimental data.Beside the surface elasticity effect and surface stress effect,the symmetry breaking and the anisotropic rolling structure are of great importance in theoretically describing the mechanical behavior of rolling-up of nanotubes.展开更多
The transport of hot electrons in inertial confinement fusion(ICF)is integrated issue due to the coupling of hydrodynamic evolution and many physical processes.A hot electron transport code is developed and coupled wi...The transport of hot electrons in inertial confinement fusion(ICF)is integrated issue due to the coupling of hydrodynamic evolution and many physical processes.A hot electron transport code is developed and coupled with the radiation hydrodynamic code MULTI1D in this study.Using the code,the slowing-down process and ablation process of the hot electron beam are simulated.The ablation pressure scaling law of hot electron beam is confirmed in our simulations.The hot electron transport is simulated in the radiation-ablated plasmas relevant to indirect-drive ICF,where the spatial profile of hot electron energy deposition is presented around the shock compressed region.It is shown that the hot electron can prominently increase the total ablation pressure in the early phase of radiation-ablated plasma.So,our study suggests that a potential-driven symmetric mechanism may occur under the irradiation of asymmetric hot electron beam.The possible degradation from the hot electron transport and preheating is also discussed.展开更多
The spatial distributions of ^(239+240)Pu and ^(137)Cs in soils from Longji Rice Terraces were investigated to evaluate soil erosion.The activity concentrations of ^(239+240)Pu and ^(137)Cs in the surface soils of the...The spatial distributions of ^(239+240)Pu and ^(137)Cs in soils from Longji Rice Terraces were investigated to evaluate soil erosion.The activity concentrations of ^(239+240)Pu and ^(137)Cs in the surface soils of the paddy fields were in the range of 0.089–0.734 and1.80–7.88 mBq/g,respectively.The activities of ^(239+240)Pu and ^(137)Cs showed very similar distribution trends,first increasing and then decreasing with increasing elevation.The 240Pu/239Pu atom ratios in the surface soils ranged from 0.162 to 0.232.The activities of ^(239+240)Pu and ^(137)Cs in the soil cores tended to be uniformly distributed within the plowed layer and declined exponentially below this depth.The mean soil erosion rates of Longji Rice Terraces estimated by ^(239+240)Pu and ^(137)Cs tracer methods were 5.44 t/(ha·a)and 5.16 t/(ha·a),respectively,which demonstrated that plutonium can replace ^(137)Cs as an ideal tracer for soil erosion research in the future.Landform features are the main factors affecting the distribution of plutonium and ^(137)Cs as well as soil erosion in the Longji Rice Terraces.展开更多
The existence of several non-symmetric balanced incomplete block designs (BIBDs) is still unknown. This is because the non-existence property for non-symmetric BIBDs is still not known and also the existing constructi...The existence of several non-symmetric balanced incomplete block designs (BIBDs) is still unknown. This is because the non-existence property for non-symmetric BIBDs is still not known and also the existing construction methods have not been able to construct these designs despite their design parameters satisfying the necessary conditions for the existence of BIBD. The study aimed to bridge this gap by introducing a new class of non-symmetric BIBDs. The proposed class of BIBDs is constructed through the combination of disjoint symmetric BIBDs. The study was able to determine that the total number of disjoint symmetric BIBDs (n) with parameters (v = b, r = k, λ) that can be obtained from an un-reduced BIBD with parameters (v, k) is given by n = r - λ. When the n symmetric disjoint BIBDs are combined, then a new class of symmetric BIBDs is formed with parameters v<sup>*</sup><sup> </sup>= v, b<sup>*</sup><sup> </sup>= nb, r<sup>*</sup><sup> </sup>= nr, k<sup>*</sup><sup> </sup>= k, λ<sup>*</sup><sup> </sup>= λ, where 2≤ n ≤ r - λ. The study established that the non-existence property of this class of BIBD was that when is not a perfect square then v should be even and when v<sup>*</sup><sup> </sup>is odd then the equation should not have a solution in integers x, y, z which are not all simultaneously zero. In conclusion, the study showed that this construction technique can be used to construct some non-symmetric BIBDs. However, one must first construct the disjoint symmetric BIBDs before one can construct the non-symmetric BIBD. Thus, the disjoint symmetric BIBDs must exist first before the non-symmetric BIBDs exist.展开更多
Climate variability impacts on cocoa production are evaluated for the first time using 31 years (1979-2010) of data from SODEXAM (climate ground- based observations) and the ex-CAISTAB in three main cocoa production r...Climate variability impacts on cocoa production are evaluated for the first time using 31 years (1979-2010) of data from SODEXAM (climate ground- based observations) and the ex-CAISTAB in three main cocoa production regions (Goh, Marahoué, and Haut-Sassandra) in the west-central part of Cote d’Ivoire. The work is a contribution to improving the quality of climate services dedicated to cocoa cultivation to ensure producers’ income and improve the yield of the production in the west-central part of Cote d’Ivoire. The results show that cocoa production is affected by the changes and variability in climate conditions (i.e. rainfall and temperature). In the Goh region, the increase in cocoa production seems to be mostly related to the augmentation of rainfall amount while in Marahoué, the increase in temperature is identified to have a more significant impact. Over the Haut-Sassandra region, both temperature and rainfall seem to have a considerable effect on the changes in cocoa production. The analysis based on linear regression by least-squares fit shows two characteristic modes (low and high-frequency variability) in the relationships between cocoa production and meteorological conditions suggesting a strong temporal signal impact related to the changes in the emblazoned surfaces. This leads to an important impact of the short-term variations of climate in cocoa production whereas, the influence of the long-term variability in climate on the cocoa yield seems marginal.展开更多
Since 2007,the Intergovernmental Panel on Climate Change(IPCC)has heavily relied on the comparison between global climate model hindcasts and global surface temperature(ST)estimates for concluding that post-1950s glob...Since 2007,the Intergovernmental Panel on Climate Change(IPCC)has heavily relied on the comparison between global climate model hindcasts and global surface temperature(ST)estimates for concluding that post-1950s global warming is mostly human-caused.In Connolly et al.,we cautioned that this approach to the detection and attribution of climate change was highly dependent on the choice of Total Solar Irradiance(TSI)and ST data sets.We compiled 16 TSI and five ST data sets and found by altering the choice of TSI or ST,one could(prematurely)conclude anything from the warming being“mostly human-caused”to“mostly natural.”Richardson and Benestad suggested our analysis was“erroneous”and“flawed”because we did not use a multilinear regression.They argued that applying a multilinear regression to one of the five ST series re-affirmed the IPCC's attribution statement.They also objected that many of the published TSI data sets were out-of-date.However,here we show that when applying multilinear regression analysis to an expanded and updated data set of 27 TSI series,the original conclusions of Connolly et al.are confirmed for all five ST data sets.Therefore,it is still unclear whether the observed warming is mostly human-caused,mostly natural or some combination of both.展开更多
A framework to estimate the mass of the universe from quarks is presented, taking spacetime into account. This is a link currently missing in our understanding of physics/science. The focus on mass-energy balance is a...A framework to estimate the mass of the universe from quarks is presented, taking spacetime into account. This is a link currently missing in our understanding of physics/science. The focus on mass-energy balance is aimed at finding a solution to the Cosmological Constant (CC) problem by attempting to quantize space-time and linking the vacuum energy density at the beginning of the universe and the current energy density. The CC problem is the famous disagreement of approximately 120 orders of magnitude between the theoretical energy density at the Planck scale and the indirectly measured cosmological energy density. Same framework is also used to determine the mass of the proton and neutron from first principles. The only input is the up quark (u-quark) mass, or precisely, the 1st generation quarks. The method assumes that the u-quark is twice as massive as the down-quark (d-quark). The gap equation is the starting point, introduced in its simplest form. The main idea is to assume that all the particles and fields in the unit universe are divided into quarks and everything else. Everything else means all fields and forces present in the universe. It is assumed that everything else can be “quark-quantized”;that is, assume that they can be quantized into similar sizeable u-quarks and/or it’s associated interactions and relations. The result is surprisingly almost as measured and known values. The proton structure and mass composition are also analysed, showing that it likely has more than 3 quarks and more than 3 valence quarks. It is also possible to estimate the percentage of dark matter, dark energy, ordinary matter, and anti-matter. Finally, the cosmological constant problem or puzzle is resolved by connecting the vacuum energy density of Quantum Field Theory (5.1E+96 kg/m<sup>3</sup>) and the energy density of General Relativity (1.04E−26 kg/m<sup>3</sup>). Upon maturation, this framework can serve as a bridging platform between Quantum Field Theory and General Relativity. Other aspects of natures’ field theories can be successfully ported to the platform. It also increases the chances of solving some of the unanswered questions in physics.展开更多
基金supported by the Natural Science Foundation of Hebei Province,China (Grant No.A2021502004)the Fundamental Research Funds for the Central Universities (Grant No.2024MS126).
文摘This paper aims to investigate the multi-soliton solutions of the coupled Lakshmanan–Porsezian–Daniel equations with variable coefficients under nonzero boundary conditions.These equations are utilized to model the phenomenon of nonlinear waves propagating simultaneously in non-uniform optical fibers.By analyzing the Lax pair and the Riemann–Hilbert problem,we aim to provide a comprehensive understanding of the dynamics and interactions of solitons of this system.Furthermore,we study the impacts of group velocity dispersion or the fourth-order dispersion on soliton behaviors.Through appropriate parameter selections,we observe various nonlinear phenomena,including the disappearance of solitons after interaction and their transformation into breather-like solitons,as well as the propagation of breathers with variable periodicity and interactions between solitons with variable periodicities.
基金Project supported by the National Natural Science Foundation of China(Nos.12172233 and U1934201)。
文摘The dynamic vibration absorber with inerter and grounded stiffness(IGDVA)is used to control a two-scale system subject to a weak periodic perturbation.The vibration suppression effect is remarkable.The amplitude of the main system coupled with absorber is significantly reduced,and the high frequency vibration completely disappears.First,through the slow-fast analysis and stability theory,it is found that the stability of the autonomous system exerts a notable regulating effect on the vibration response of the non-autonomous system.After adding the dynamic vibrator absorber,the center in the autonomous system changes to an asymptotically stable focus,consequently suppressing the vibration in the non-autonomous system.Further research reveals that the parameters of the absorber affect the real parts of the eigenvalues of the autonomous system,thereby regulating the stability of the system.Transitioning from a qualitative standpoint to a quantitative approach,a comparison of the solutions before and after the introduction of the dynamic absorber reveals that,when the grounded stiffness ratio and the mass ratio of the dynamic absorber are not equal,the high-frequency part in the analytical solution disappears.As a result,this leads to a reduction in the amplitude of the trajectory,achieving a vibration reduction effect.
基金Project supported by the Fundamental Research Fund for the Central Universities of Chinathe Research Project for Independently Cultivate Talents of Hebei Agricultural University (Grant No.ZY2023007)。
文摘Combining the mean field Pozhar-Gubbins(PG)theory and the weighted density approximation,a novel method for local thermal conductivity of inhomogeneous fluids is proposed.The correlation effect that is beyond the mean field treatment is taken into account by the simulation-based empirical correlations.The application of this method to confined argon in slit pore shows that its prediction agrees well with the simulation results,and that it performs better than the original PG theory as well as the local averaged density model(LADM).In its further application to the nano-fluidic films,the influences of fluid parameters and pore parameters on the thermal conductivity are calculated and investigated.It is found that both the local thermal conductivity and the overall thermal conductivity can be significantly modulated by these parameters.Specifically,in the supercritical states,the thermal conductivity of the confined fluid shows positive correlation to the bulk density as well as the temperature.However,when the bulk density is small,the thermal conductivity exhibits a decrease-increase transition as the temperature is increased.This is also the case in which the temperature is low.In fact,the decrease-increase transition in both the small-bulk-density and low-temperature cases arises from the capillary condensation in the pore.Furthermore,smaller pore width and/or stronger adsorption potential can raise the critical temperature for condensation,and then are beneficial to the enhancement of the thermal conductivity.These modulation behaviors of the local thermal conductivity lead immediately to the significant difference of the overall thermal conductivity in different phase regions.
基金supported by National Magnetic Confinement Fusion Energy Development Research Project(Nos.2022YFE03070003 and 2019YFE03070000)Natural Science Foundation of Hunan Province(No.2020JJ4515)+6 种基金Key Projects of Hunan Provincial Department of Education(No.20A432)the Government Sponsored Study Abroad Program of the Chinese Scholarship Council(CSC)(No.202108430056)Anhui Provincial Natural Science Foundation(No.2308085MA23)IAEA Coordinated Research Project F43026(No.26480)the National Key Research&Development Program of China(No.2018YFE0303103)National Natural Science Foundation of China(Nos.11875287 and 12275314)Anhui Provincial Key Research&Development Project(No.205258180096)。
文摘A program developed with COMSOL software integrates EAST four-strap antenna coupling with the double-stub Ferrite tuners(FT)impedance matching,obtaining physical quantities crucial for predicting the overall performance of the ion cyclotron resonance heating(ICRH)antenna and matching system.These quantities encompass S-matrix,port complex impedance,reflection coefficients,electric field and voltage distribution,and optimal matching settings.In this study,we explore the relationship between S-matrix,reflection coefficients,port complex impedance,and frequency.Then,we analyze the impact of Faraday screens placement position and transparency,the distance from the Faraday screen(FS)to the current straps(CS),the relative distance between ports,and the characteristic impedance of the transmission line on the coupling characteristic impedance of the EAST ICRH system.Finally,we simulate the electric field distribution and voltage distribution of the EAST ICRH system for plasma heating with double-stub FT impedance matching.Using optimized parameters,the coupling power of the ICRH system can be approximately doubled.The results present herein may offer guidance for the design of high-power,long-pulse operation ICRH antenna systems.
文摘This paper models the giraffe’s jugular veins as a uniform collapsible tube from a rigid skull. The equations governing one-dimensional steady flow through such a tube for various conditions have been developed. The effects of inertial and inclination angles that have not been discussed previously have been included. It has been shown that different flows for a uniform tube (vein) are possible. However, this flow matches that of a jugular vein which is supercritical, and the steady solution has been given by the balance between the driving forces of gravity and the viscous resistance to the flow at the right atrium of the heart must be sub-critical for a fixed right-atrium pressure which means that an elastic jump is required to return the flow to sub-critical from the supercritical flow upstream this type of relationship gives rise to flow limitation at the same time given any right atrium fixed pressure there exists a maximum flow rate which when exceeded the boundary conditions of the flow do not hold boundary conditions at the right atrium are not satisfied hence making the steady flow impossible this mechanism of flow limitation is slightly different from the other one in that causes airways through forced expiration from the observation made it is clearly shown that there is an intravascular pressure difference with a change in height.
文摘In recent years, there has been remarkable progress in the performance of metal halide perovskite solar cells. Studies have shown significant interest in lead-free perovskite solar cells (PSCs) due to concerns about the toxicity of lead in lead halide perovskites. CH3NH3SnI3 emerges as a viable alternative to CH3NH3PbX3. In this work, we studied the effect of various parameters on the performance of lead-free perovskite solar cells using simulation with the SCAPS 1D software. The cell structure consists of α-Fe2O3/CH3NH3SnI3/PEDOT: PSS. We analyzed parameters such as thickness, doping, and layer concentration. The study revealed that, without considering other optimized parameters, the efficiency of the cell increased from 22% to 35% when the perovskite thickness varied from 100 to 1000 nm. After optimization, solar cell efficiency reaches up to 42%. The optimization parameters are such that, for example, for perovskite: the layer thickness is 700 nm, the doping concentration is 1020 and the defect density is 1013 cm−3, and for hematite: the thickness is 5 nm, the doping concentration is 1022 and the defect concentration is 1011 cm−3. These results are encouraging because they highlight the good agreement between perovskite and hematite when used as the active and electron transport layers, respectively. Now, it is still necessary to produce real, viable photovoltaic solar cells with the proposed material layer parameters.
文摘The dynamically shifted oscillator is investigated quantum mechanically, both analytically and numerically. It is shown that the commonly used method of solving the Schrödinger equation using power series results in incorrect eigenvalues and eigenfunctions.
文摘The application potential of cellulosic materials in natural composites and other fields needs to be explored to develop innovative, sustainable, lightweight, functional biomass materials that are also environmentally friendly. This study investigated Typha angustifolia (Typha sp.) as a potential new raw material for extracting cellulose nanocrystals (CNCs) for application in wastewater treatment composites. Alkaline treatments and bleaching were used to remove cellulose from the stem fibres. The CNCs were then isolated from the recovered cellulose using acid hydrolysis. The study showed a few distinct functional groups (O-H, -C-H, =C-H and C-O, and C-O-C) in the Fourier Transform Infrared (FTIR) spectra. A scanning electron microscope (SEM) revealed the smooth surface of CPC and CNCs, which resulted from removing lignin and hemicellulose from powdered Typha angustifolia. Based on the crystalline index, the powdered Typha angustifolia, CPC, and CNCs were 42.86%, 66.94% and 77.41%. The loss of the amorphous section of the Typha sp. fibre resulted in a decrease in particle size. It may be inferred from the features of a Typha sp. CNC that CNCs may be employed as reinforcement in composites for wastewater treatment.
文摘We show that an intrinsically nonlinear oscillator can always be transformed into a linear or harmonic oscillator by addition of a constant force, which shifts the equilibrium position of the oscillator.
文摘This article examines the dynamics for stochastic plate equations with linear memory in the case of bounded domain. We investigate the existence of solutions and bounded absorbing set by using the uniform pullback attractors on the tails estimates, and the asymptotic compactness of the random dynamical system is proved by decomposition method, and then we obtain the existence of a random attractor.
文摘The simulation by the Monte Carlo method executed by the software PyPENELOPE proved effective to specify the particle propagation characteristics by calculating the absorption fractions, backscattering and transmission of electrons and secondary photons under the incidence of 0.5 to 20 KeV range of primary electrons. More than 99.9% of the primary electrons were transmitted in the 125 nm thick MgO/TiO<sub>2</sub> material at 20 KeV. This occurred because several interactions took place in the transmitted primary irradiation such as characteristic, fluorescence, and bremsstrahlung produced when of the occupation of the KL3, KL2, KM3, and KM2 shell and sub-shell of titanium and magnesium which are the elements with a high atomic number in the material. The transmission particle characteristic of this material is therefore an indicator capable of improving the electrical performance and properties of the sensor.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11974108 and 11574082)Fundamental Research Funds for the Central Universities (Grant No. 2021MS046)the Natural Science Foundation of Shandong Province, China (Grant No. ZR2019MA020)。
文摘We study the strong nonlinear optical dynamics of nanosecond pulsed Laguerre–Gaussian laser beams of high-order radial modes with zero orbital angular momentum propagating in the fullerene C60molecular medium. It is found that the spatiotemporal profile of the incident pulsed Laguerre–Gaussian laser beam is strongly reshaped during its propagation in the C60molecular medium. The centrosymmetric temporal profile of the incident pulse gradually evolves into a noncentrosymmetric meniscus shape, and the on-axis pulse duration is clearly depressed. Furthermore, the field intensity is distinctly attenuated due to the field-intensity-dependent reverse saturable absorption, and clear optical power limiting behavior is observed for different orders of the input pulsed Laguerre–Gaussian laser beams before the takeover of the saturation effect;the lower the order of the Laguerre–Gaussian beam, the lower the energy transmittance.
文摘The origins of superconductivity and pairing symmetry of order parameters are still controversial problems for FeSe thin films up to date.Under the Neumann boundary conditions,the electromagnetic properties of this system are investigated using the two-band Ginzburg-Landau theory.We calculate the temperature dependence of upper critical field in arbitrary direction and critical supercurrent density through the FeSe film.It is revealed that the normalized upper critical field is independent of the film thickness and all of our theoretical results are in accordance with the experimental data.These thus strongly indicate the existence of two-gap s-wave superconductivity in this material.
基金Project supported by the Natural Science Foundation of Shanxi Province,China (Grant No.201901D111316)the National Natural Science Foundation of China (Grant No.11874245)+1 种基金the Teaching Reform and Innovation Pproject of Colleges and Universities in Shanxi Province,China (Grant No.J2021508)the Natural Science Foundation of Inner Mongolia Autonomous Region,China (Grant No.2020MS06007)。
文摘A continuum theoretical scheme for self-rolling nanotubes from bilayers by mismatch is obtained by considering surface elasticity,surface stress,and symmetry lowering effects.For an ultrathin nanofilm with only several nanometers in thickness,isotropic mismatch,and isotropic surface stress usually induce anisotropic rolling behavior.The isotropic Timoshenko formula should be modified anisotropically to explain the mechanical behavior of anisotropic rolling structure of nanotubes accurately.The nanofilm rolls up in tangential direction while remaining straight in cylindrical direction theoretically.Therefore,in this paper the anisotropic shape of nanotubes is taken into consideration.Along the cylindrical direction,although it maintains straight and its residual strain is uniform,the stress varies in the radial direction due to the Poisson's effect of tangential strain.The results of the current theory applied to Si-Si nanotube,InAs-GaAs nanotube,and InGaAs-Cr nanotube systems show good agreement with the experimental data.Beside the surface elasticity effect and surface stress effect,the symmetry breaking and the anisotropic rolling structure are of great importance in theoretically describing the mechanical behavior of rolling-up of nanotubes.
基金Project supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA25050600)the DCI joint team。
文摘The transport of hot electrons in inertial confinement fusion(ICF)is integrated issue due to the coupling of hydrodynamic evolution and many physical processes.A hot electron transport code is developed and coupled with the radiation hydrodynamic code MULTI1D in this study.Using the code,the slowing-down process and ablation process of the hot electron beam are simulated.The ablation pressure scaling law of hot electron beam is confirmed in our simulations.The hot electron transport is simulated in the radiation-ablated plasmas relevant to indirect-drive ICF,where the spatial profile of hot electron energy deposition is presented around the shock compressed region.It is shown that the hot electron can prominently increase the total ablation pressure in the early phase of radiation-ablated plasma.So,our study suggests that a potential-driven symmetric mechanism may occur under the irradiation of asymmetric hot electron beam.The possible degradation from the hot electron transport and preheating is also discussed.
基金supported by the National Natural Science Foundation of China(No.12175046)the Guangxi Natural Science Foundation(No.2021GXNSFBA196001)the One-HundredTalents Program of Guangxi Colleges。
文摘The spatial distributions of ^(239+240)Pu and ^(137)Cs in soils from Longji Rice Terraces were investigated to evaluate soil erosion.The activity concentrations of ^(239+240)Pu and ^(137)Cs in the surface soils of the paddy fields were in the range of 0.089–0.734 and1.80–7.88 mBq/g,respectively.The activities of ^(239+240)Pu and ^(137)Cs showed very similar distribution trends,first increasing and then decreasing with increasing elevation.The 240Pu/239Pu atom ratios in the surface soils ranged from 0.162 to 0.232.The activities of ^(239+240)Pu and ^(137)Cs in the soil cores tended to be uniformly distributed within the plowed layer and declined exponentially below this depth.The mean soil erosion rates of Longji Rice Terraces estimated by ^(239+240)Pu and ^(137)Cs tracer methods were 5.44 t/(ha·a)and 5.16 t/(ha·a),respectively,which demonstrated that plutonium can replace ^(137)Cs as an ideal tracer for soil erosion research in the future.Landform features are the main factors affecting the distribution of plutonium and ^(137)Cs as well as soil erosion in the Longji Rice Terraces.
文摘The existence of several non-symmetric balanced incomplete block designs (BIBDs) is still unknown. This is because the non-existence property for non-symmetric BIBDs is still not known and also the existing construction methods have not been able to construct these designs despite their design parameters satisfying the necessary conditions for the existence of BIBD. The study aimed to bridge this gap by introducing a new class of non-symmetric BIBDs. The proposed class of BIBDs is constructed through the combination of disjoint symmetric BIBDs. The study was able to determine that the total number of disjoint symmetric BIBDs (n) with parameters (v = b, r = k, λ) that can be obtained from an un-reduced BIBD with parameters (v, k) is given by n = r - λ. When the n symmetric disjoint BIBDs are combined, then a new class of symmetric BIBDs is formed with parameters v<sup>*</sup><sup> </sup>= v, b<sup>*</sup><sup> </sup>= nb, r<sup>*</sup><sup> </sup>= nr, k<sup>*</sup><sup> </sup>= k, λ<sup>*</sup><sup> </sup>= λ, where 2≤ n ≤ r - λ. The study established that the non-existence property of this class of BIBD was that when is not a perfect square then v should be even and when v<sup>*</sup><sup> </sup>is odd then the equation should not have a solution in integers x, y, z which are not all simultaneously zero. In conclusion, the study showed that this construction technique can be used to construct some non-symmetric BIBDs. However, one must first construct the disjoint symmetric BIBDs before one can construct the non-symmetric BIBD. Thus, the disjoint symmetric BIBDs must exist first before the non-symmetric BIBDs exist.
文摘Climate variability impacts on cocoa production are evaluated for the first time using 31 years (1979-2010) of data from SODEXAM (climate ground- based observations) and the ex-CAISTAB in three main cocoa production regions (Goh, Marahoué, and Haut-Sassandra) in the west-central part of Cote d’Ivoire. The work is a contribution to improving the quality of climate services dedicated to cocoa cultivation to ensure producers’ income and improve the yield of the production in the west-central part of Cote d’Ivoire. The results show that cocoa production is affected by the changes and variability in climate conditions (i.e. rainfall and temperature). In the Goh region, the increase in cocoa production seems to be mostly related to the augmentation of rainfall amount while in Marahoué, the increase in temperature is identified to have a more significant impact. Over the Haut-Sassandra region, both temperature and rainfall seem to have a considerable effect on the changes in cocoa production. The analysis based on linear regression by least-squares fit shows two characteristic modes (low and high-frequency variability) in the relationships between cocoa production and meteorological conditions suggesting a strong temporal signal impact related to the changes in the emblazoned surfaces. This leads to an important impact of the short-term variations of climate in cocoa production whereas, the influence of the long-term variability in climate on the cocoa yield seems marginal.
基金financial support from the Center for Environmental Research and Earth Sciences(CERES,www.ceres-science.com)while carrying out the research for this paperlong-term support from NASA,NSF,Tennessee State University,and the State of Tennessee through its Centers of Excellence Programthe support of the grant PID-5265TC of the National Technological University of Argentina。
文摘Since 2007,the Intergovernmental Panel on Climate Change(IPCC)has heavily relied on the comparison between global climate model hindcasts and global surface temperature(ST)estimates for concluding that post-1950s global warming is mostly human-caused.In Connolly et al.,we cautioned that this approach to the detection and attribution of climate change was highly dependent on the choice of Total Solar Irradiance(TSI)and ST data sets.We compiled 16 TSI and five ST data sets and found by altering the choice of TSI or ST,one could(prematurely)conclude anything from the warming being“mostly human-caused”to“mostly natural.”Richardson and Benestad suggested our analysis was“erroneous”and“flawed”because we did not use a multilinear regression.They argued that applying a multilinear regression to one of the five ST series re-affirmed the IPCC's attribution statement.They also objected that many of the published TSI data sets were out-of-date.However,here we show that when applying multilinear regression analysis to an expanded and updated data set of 27 TSI series,the original conclusions of Connolly et al.are confirmed for all five ST data sets.Therefore,it is still unclear whether the observed warming is mostly human-caused,mostly natural or some combination of both.
文摘A framework to estimate the mass of the universe from quarks is presented, taking spacetime into account. This is a link currently missing in our understanding of physics/science. The focus on mass-energy balance is aimed at finding a solution to the Cosmological Constant (CC) problem by attempting to quantize space-time and linking the vacuum energy density at the beginning of the universe and the current energy density. The CC problem is the famous disagreement of approximately 120 orders of magnitude between the theoretical energy density at the Planck scale and the indirectly measured cosmological energy density. Same framework is also used to determine the mass of the proton and neutron from first principles. The only input is the up quark (u-quark) mass, or precisely, the 1st generation quarks. The method assumes that the u-quark is twice as massive as the down-quark (d-quark). The gap equation is the starting point, introduced in its simplest form. The main idea is to assume that all the particles and fields in the unit universe are divided into quarks and everything else. Everything else means all fields and forces present in the universe. It is assumed that everything else can be “quark-quantized”;that is, assume that they can be quantized into similar sizeable u-quarks and/or it’s associated interactions and relations. The result is surprisingly almost as measured and known values. The proton structure and mass composition are also analysed, showing that it likely has more than 3 quarks and more than 3 valence quarks. It is also possible to estimate the percentage of dark matter, dark energy, ordinary matter, and anti-matter. Finally, the cosmological constant problem or puzzle is resolved by connecting the vacuum energy density of Quantum Field Theory (5.1E+96 kg/m<sup>3</sup>) and the energy density of General Relativity (1.04E−26 kg/m<sup>3</sup>). Upon maturation, this framework can serve as a bridging platform between Quantum Field Theory and General Relativity. Other aspects of natures’ field theories can be successfully ported to the platform. It also increases the chances of solving some of the unanswered questions in physics.