Purpose:The goal of this study is to analyze the relationship between funded and unfunded papers and their citations in both basic and applied sciences.Design/methodology/approach:A power law model analyzes the relati...Purpose:The goal of this study is to analyze the relationship between funded and unfunded papers and their citations in both basic and applied sciences.Design/methodology/approach:A power law model analyzes the relationship between research funding and citations of papers using 831,337 documents recorded in the Web of Science database.Findings:The original results reveal general characteristics of the diffusion of science in research fields:a)Funded articles receive higher citations compared to unfunded papers in journals;b)Funded articles exhibit a super-linear growth in citations,surpassing the increase seen in unfunded articles.This finding reveals a higher diffusion of scientific knowledge in funded articles.Moreover,c)funded articles in both basic and applied sciences demonstrate a similar expected change in citations,equivalent to about 1.23%,when the number of funded papers increases by 1%in journals.This result suggests,for the first time,that funding effect of scientific research is an invariant driver,irrespective of the nature of the basic or applied sciences.Originality/value:This evidence suggests empirical laws of funding for scientific citations that explain the importance of robust funding mechanisms for achieving impactful research outcomes in science and society.These findings here also highlight that funding for scientific research is a critical driving force in supporting citations and the dissemination of scientific knowledge in recorded documents in both basic and applied sciences.Practical implications:This comprehensive result provides a holistic view of the relationship between funding and citation performance in science to guide policymakers and R&D managers with science policies by directing funding to research in promoting the scientific development and higher diffusion of results for the progress of human society.展开更多
Combined bodies of rock-like material and rock are widely encountered in geotechnical engineering,such as tunnels and mines.The existing theoretical models describing the stress-strain relationship of a combined body ...Combined bodies of rock-like material and rock are widely encountered in geotechnical engineering,such as tunnels and mines.The existing theoretical models describing the stress-strain relationship of a combined body lack a binary feature.Based on effective medium theory,this paper presents the governing equation of the“elastic modulus”for combined and single bodies under triaxial compressive tests.A binary effective medium model is then established.Based on the compressive experiment of concretegranite combined bodies,the feasibility of determining the stress threshold based on crack axial strain is discussed,and the model is verified.The model is further extended to coal-rock combined bodies of more diverse types,and the variation laws of the compressive mechanical parameters are then discussed.The results show that the fitting accuracy of the model with the experimental curves of the concretegranite combined bodies and various types of coal-rock combined bodies are over 95%.The crack axial strain method can replace the crack volumetric strain method,which clarifies the physical meanings of the model parameters.The variation laws of matrix parameters and crack parameters are discussed in depth and are expected to be more widely used in geotechnical engineering.展开更多
For a black hole with two horizons, the effective entropy is assumed to be a linear combination of the two entropies of the outer and inner horizons. In terms of the effective thermodynamic quantities the effective Be...For a black hole with two horizons, the effective entropy is assumed to be a linear combination of the two entropies of the outer and inner horizons. In terms of the effective thermodynamic quantities the effective Bekenstein-Smarr formula and the effective first law of thermodynamics are derived.展开更多
By means of a representation of the elementary objects by the Lagrange density and by the commutators of the communication relations, correlations can be formed using the Fourier transform, which under the conditions ...By means of a representation of the elementary objects by the Lagrange density and by the commutators of the communication relations, correlations can be formed using the Fourier transform, which under the conditions of the Hamilton principle, describes correlation structures of the elementary objects with oscillator properties. The correlation structures obtained in this way are characterized by physical information, the essential component of which is the action. The correlation structures describe the physical properties and their interactions under the sole condition of the Hamilton’s principle. The structure, the properties and the interactions of elementary objects can be led back in this way to a fundamental four dimensional structure, which is therefore in their different modifications the building block of nature. With the presented method, an alternative interpretation of elementary physical effects to quantum mechanics is obtained. This report provides an overview of the fundamentals and statements of physical information theory and its consequences for understanding the nature of elementary objects.展开更多
This paper explains the Olbers paradox and the origin of cosmic microwave background radiation (CMBR) from the viewpoint of the quantum redshift effect. The derived formula dispels the Olbers paradox, confirming that ...This paper explains the Olbers paradox and the origin of cosmic microwave background radiation (CMBR) from the viewpoint of the quantum redshift effect. The derived formula dispels the Olbers paradox, confirming that the CMBR originates from the superposition of light radiated by stars in the whole universe, not the relic of the Big Bang. The dark-night sky and CMBR are all caused by Hubble redshift—the physical mechanism is the quantum redshift of the photon rather than cosmic expansion. So this theory supports the infinite and steady cosmology.展开更多
Focused on the Klinkenberg effect on gas seepage, the independently developed triaxial experimental system of gas seepage was applied to conduct research on the seepage characteristics of coal seam gas. By means of ex...Focused on the Klinkenberg effect on gas seepage, the independently developed triaxial experimental system of gas seepage was applied to conduct research on the seepage characteristics of coal seam gas. By means of experimental data analysis and theoretical derivation, a calculation method of coal seam gas permeability was proposed, which synthesized the respective influences of gas dynamic viscosity, compressibility factor and Klinkenberg effect. The study results show that the Klinkenberg effect has a significant influence on the coal seam gas seepage, the permeability estimated with the method considering the Klinkenberg effect is correct, and this permeability can fully reflect the true seepage state of the gas. For the gas around the standard conditions, the influences of dynamic viscosity and compressibility factor on the permeability may be ignored. For the gas deviating far away from the standard conditions, the influences of dynamic viscosity and compressibility factor on the permeability must be considered. The research results have certain guiding significance in forming a correct understanding of the Klinkenberg effect and selecting a more accurate calculation method for the permeability of coal containing gas.展开更多
This article presents a mathematical model for simulating the mechanical behaviour of lightning strikes and analysing the resulting damage to the soil.This article focuses on the electro-thermal effect and seepage cau...This article presents a mathematical model for simulating the mechanical behaviour of lightning strikes and analysing the resulting damage to the soil.This article focuses on the electro-thermal effect and seepage caused by lightning strikes in particular.Then,a numerical model based on the conservation laws of momentum,mass and energy is developed for soil subjected to lightning strikes.Comparisons to field observations and theoretical calculations are used to demonstrate the efficacy and accuracy of numerical simulations.The findings demonstrate that lightning strikes can cause soils to experience both seepage force and heat stress.Under the calculative condition of this article:by increasing the intrinsic permeability of the soil,k_(p)(≥10^(-10)m^(2)),the seepage force can be effectively reduced,hence reducing the risk of lightning strikes;improving the electrical conductivity of the soil β(≥10^(-1) S/m^(2))and lowering its thermal expansion coefficient(≤10^(-6)K^(-1))can greatly reduce the damage caused by lightning strikes to the soil.The preceding investigations demonstrate that the suggested model is capable of evaluating mechanical damage caused by lightning in the soil,and the findings contribute to a better understanding of soil mechanical response to lightning strikes.展开更多
Using micro-level data from China Employer-Employee Survey(CEES), this paper conducts an empirical analysis of firms' heterogeneous characteristics in the implementation of the Labor Contract Law and its effects o...Using micro-level data from China Employer-Employee Survey(CEES), this paper conducts an empirical analysis of firms' heterogeneous characteristics in the implementation of the Labor Contract Law and its effects on employees. Our findings are as follows: With China's economic development, firms more proactively implement the Labor Contract Law, resulting in a higher percentage of employees with labor contracts. Labor contracts significantly increase the probability of employees in receiving social insurances, such as pension, health, unemployment, work injury and birth insurances, and have a significantly positive effect on wage income. Longer term of labor contract corresponds to stronger employment protection, and such an effect is highly robust. Larger firms with higher capital-labor ratios have better results in implementing the Labor Contract Law. And employees of private and labor-intensive firms have poorer coverage of employment and social protection; such firms should be given focal attention in the law's implementation.展开更多
Fe 100- x Ni x alloys of ultrafine particle with the average grain size of about 10 nm were synthesized by mechanically alloying process. The samples were investigated by X ray diffraction and measure...Fe 100- x Ni x alloys of ultrafine particle with the average grain size of about 10 nm were synthesized by mechanically alloying process. The samples were investigated by X ray diffraction and measurements of the saturation magnetization and coercivity force. Both b.c.c and f.c.c phase exist within a wide range for Fe 100- x Ni x , while x ≤45. The effective magnetic anisotropy K e was measured by applying the law of approach to saturation. The value of K e decreases with an increase of Ni content. It is noticed that the strain anisotropy makes a large contribution to the magnetic anisotropy. The estimation of grain size leads to the determination of the single domain critical size and domain wall energy. The exchange stiffness and exchange integral deduced from the relationship between the effective magnetic anisotropy and domain wall energy are in agreement with that calculated by other methods.展开更多
The known statistical data show that the distribution of popular elements and people’s income presents the characteristics of power law distribution.At present,the explanation for this phenomenon is mostly through th...The known statistical data show that the distribution of popular elements and people’s income presents the characteristics of power law distribution.At present,the explanation for this phenomenon is mostly through the“rich get richer”theory,but the author believes that this theory has major flaws and fails to provide a reasonable explanation for many phenomena.Therefore,the author expands some empirical and recognized theories in a similar direction in logic,and derives a logical mathematical model through the derivation of mathematical formulas,so as to explain the phenomenon that the distribution of popular elements and people’s income presents a power-law distribution.Then,by analyzing various characteristics of social networks and comparing them with some phenomena in nature,the conclusion can be extended to all self-organizing groups in nature.展开更多
Based on the divergence theorem, we reveal that the Fickian first law relevant to the diffusion flux |J(t,x,y,z) > in the time and space is incomplete without an integral constant |J0(t) > for the integral of Fi...Based on the divergence theorem, we reveal that the Fickian first law relevant to the diffusion flux |J(t,x,y,z) > in the time and space is incomplete without an integral constant |J0(t) > for the integral of Fickian second law. The new diffusion flux (NDF) taking it into account shows that we can systematically understand the problems of one-way diffusion, impurity diffusion and self-diffusion as a special case of the interdiffusion. Applying the NDF to the interdiffusion problem between metal plates, it is clarified that the Kirkenkall effect is caused by |J0(t) > and also that the interdiffusion coefficients in alloy can be easily obtained. The interdiffusion problems are reasonably solved regardless of the intrinsic diffusion conception. Thus the NDF to replace the Fickian first law is an essential equation in physics.展开更多
The light propagation through system a polarizer-analyzer is investigated on the basis of quantum conceptions about the nature of light. It is shown, that Malus law based on principles of classical electrodynamics not...The light propagation through system a polarizer-analyzer is investigated on the basis of quantum conceptions about the nature of light. It is shown, that Malus law based on principles of classical electrodynamics not completely takes into account all effects which can occur at the light propagation through system a polarizer-analyzer. The phenomenon of possible change of frequency of light in particular drops out, for example in the region of X-ray radiation. The deduction of Malus law based on quantum principles is given. For comparison the differential effective section of interaction of a photon and electron with take into account of rotation of a plane of polarization of a photon in Compton’s effect is found.展开更多
The two one-state-variable, rate- and state-dependent friction laws, i.e., the slip and slowness laws, are com- pared on the basis of dynamical behavior of a one-degree-of-freedom spring-slider model through numerical...The two one-state-variable, rate- and state-dependent friction laws, i.e., the slip and slowness laws, are com- pared on the basis of dynamical behavior of a one-degree-of-freedom spring-slider model through numerical simulations. Results show that two (normalized) model parameters, i.e., A (the normalized characteristic slip distance) and β-α (the difference in two normalized parameters of friction laws), control the solutions. From given values of △, β, and α, for the slowness laws, the solution exists and the unique non-zero fixed point is stable when △〉(β-α), yet not when △ 〈(β-α). For the slip law, the solution exists for large ranges of model parameters and the number and stability of the non-zero fixed points change from one case to another. Results suggest that the slip law is more appropriate for controlling earthquake dynamics than the slowness law.展开更多
Atmospheric effects on interferometric synthetic aperture radar(InSAR) measurements are quantitatively studied based on a tandem pair of SAR data and a month-long continuous GPS tracking data obtained at six stations....Atmospheric effects on interferometric synthetic aperture radar(InSAR) measurements are quantitatively studied based on a tandem pair of SAR data and a month-long continuous GPS tracking data obtained at six stations. Differential atmospheric signals extracted from the SAR data for two selected areas show apparent power law characteristics. The RMS values of the signals are 2.04 and 3.66 rad respectively for the two areas. These differential delays can potentially cause in the two areas peak-to-peak deformation errors of 3.64 and 6.52cm, respectively, at the 95% confidence level and Gaussian distribution. The respective potential peak-to-peak DEM errors are 123 and 221 m. The GPS tropospheric total zenith delays estimate indicates that a peak-to-peak error of about 7.8cm can potentially be caused in a SAR interferogram with only 1 d interval at the 95% confidence level. The error increases to about 9.6cm for 10 d interval. The potential peak-to-peak DEM and deformation errors estimated from GPS total zenith delay measurements are however quite similar to those estimated from InSAR data. This provides us with a useful tool to pre-estimate the potential atmospheric effects in a SAR interferogram before we order the SAR images. Nevertheless, the results reveal that even in a small area the atmospheric delays can obscure centimetre level ground displacements and introduce a few hundred meters of errors to derived DEM.展开更多
To study the additional aerodynamic effect on a bridge girder under the action of wind-driven rain, the rainfall similarity considering raindrop impact and surface water is first given. Then, the dynamic characteristi...To study the additional aerodynamic effect on a bridge girder under the action of wind-driven rain, the rainfall similarity considering raindrop impact and surface water is first given. Then, the dynamic characteristics and the process of vortex and flutter generation of the segment models under different rain intensities and angles of attack are tested by considering several typical main girder sections as examples. The test results indicate that the start and end wind speeds,interval length and number of vortex vibrations remain unchanged when it is raining, rainfall will reduce the windinduced vortex response. When test rain intensity is large, the decrease of amplitude is obvious. However, after considering the rain intensity similarity in this study, all of actual maximum rain intensities after conversion approach the domestic extreme rain intensity of approximately 709 mm/h. It can be observed that rainfall has a limited influence on the dynamic characteristics of the structure and vortex vibration response. When the test rain intensity is 120 mm/h, the critical wind speed of the model flutter increases by 20%-30%. However, after considering the rain intensity similarity ratio, the influence of rainfall on the wind-induced flutter instability of the bridge girder may be ignored.展开更多
Reservoir impoundment is related to several hydraulic engineering concerns,including irreversible valley contractions,landslides and reservoir-induced earthquakes.However,these phenomena,such as valley contractions,ar...Reservoir impoundment is related to several hydraulic engineering concerns,including irreversible valley contractions,landslides and reservoir-induced earthquakes.However,these phenomena,such as valley contractions,are hardly to be explained by the conventional method.The scientific understanding of water effects during impoundment and their hazards to hydraulic structure are needed.The effective stress law for fissured rock masses is introduced in the elasto-plastic model employing the Drucker-Prager criterion and implemented in the three dimension(3D)nonlinear finite element method(FEM)program Three-dimensional FINite Element(TFINE).The slope deforms towards river-way during impoundment since the increasing pore pressure in fissures changes stress state and leads to additional plastic deformation in the rock materials.The value of Biot coefficient and the influence of water on rock materials are discussed in detail.Thus,the mechanism of slope deformation during the impoundment of Jinping-I arch dam is revealed,and the deformation is accurately measured.The application of the effective stress law provides a method to consider stress assessment,deformation evaluation and stability estimate of hydraulic structures during the impoundment process.This is a beneficial exploration and an improvement of hydraulic engineering design.展开更多
This paper presents a novel idea of utilizing the reactional torque of the conventional electric motor as a linear output for propulsion in addition to the conventional torque output of the rotor. The idea is demonstr...This paper presents a novel idea of utilizing the reactional torque of the conventional electric motor as a linear output for propulsion in addition to the conventional torque output of the rotor. The idea is demonstrated by a theoretical proposal of linearizing the stator of one of the most used motors </span><span style="font-family:Verdana;">in Electrical Vehicles and Hybrid Vehicles</span><span style="font-family:""><span style="font-family:Verdana;">. The proposed Linear Stator Motor is a </span><span style="font-family:Verdana;">simple modification without involving any functional change of the conventional motor. Though theoretical, the indicated possible input </span><span style="font-family:Verdana;">energy saving of more than 75% as compared to the conventional motor is no surprise, as by linearizing the stator, an almost equal linear propulsion output is added to the conventional rotor output. In addition to this remarkable saving in input energy, the proposed Linear Stator Motor that suits all type</span></span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> of vehicle</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;">, can maintain propulsion without the need for a mechanical transmission system. Also, in </span><span style="font-family:Verdana;">the </span><span style="font-family:Verdana;">case of watercraft and aircraft vehicles, no external mechanical propulsion drive system is required. It is just an internal force that can push the vehicle forward, backward</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> or laterally, while the conventional rotor output can be utilized for energy recovery by driving a DC generator.展开更多
Epitaxial Mn_(4)N films with different thicknesses were fabricated by facing-target reactive sputtering and their anomalous Hall effect(AHE)is investigated systematically.The Hall resistivity shows a reversed magnetic...Epitaxial Mn_(4)N films with different thicknesses were fabricated by facing-target reactive sputtering and their anomalous Hall effect(AHE)is investigated systematically.The Hall resistivity shows a reversed magnetic hysteresis loop with the magnetic field.The magnitude of the anomalous Hall resistivity sharply decreases with decreasing temperature from300 K to 150 K.The AHE scaling law in Mn_(4)N films is influenced by the temperature-dependent magnetization,carrier concentration and interfacial scattering.Different scaling laws are used to distinguish the various contributions of AHE mechanisms.The scaling exponentγ>2 for the conventional scaling in Mn_(4)N films could be attributed to the residual resistivityρ_(xx0).The longitudinal conductivityσ_(xx)falls into the dirty regime.The scaling ofρ_(AH)=αρ_(xx0)+bρ_(xx)~nis used to separate out the temperature-independentρ_(xx0)from extrinsic contribution.Moreover,the relationship betweenρ_(AH)and pxx is fitted by the proper scaling to clarify the contributions from extrinsic and intrinsic mechanisms of AHE,which demonstrates that the dominant mechanism of AHE in the Mn4 N films can be ascribed to the competition between skew scattering,side jump and the intrinsic mechanisms.展开更多
The three most common variations of Fitts’ index of difficulty are the Fitts formulation, the Welford formulation, and the Shannon formulation. A recent paper by Hoffmann [1] critiqued the three and concluded that th...The three most common variations of Fitts’ index of difficulty are the Fitts formulation, the Welford formulation, and the Shannon formulation. A recent paper by Hoffmann [1] critiqued the three and concluded that the Fitts and Welford formulations are valid and that the Shannon formulation is invalid. In this paper, we challenge Hoffmann’s position regarding the Shannon formulation. It is argued that the issue of validity vs. invalidity is ill-conceived, given that Fitts’ law is a “model by analogy” with no basis in human motor control. The relevant questions are of utility: Does a model work? How well? Is it useful? Where alternative formulations exist, they may be critiqued and compared for strengths and weaknesses, but validity is an irrelevant construct. In a reanalysis of data from Fitts’ law experiments, models built using the Shannon formulation are (re)affirmed to be as good as, and generally better than, those built using the Fitts or Welford formulation.展开更多
A mechanical model is established for mode II interfacial crack static growing along an elastic-elastic power law creeping bimaterial interface. For frictional contact of boundary conditions on crack faces, asymptotic...A mechanical model is established for mode II interfacial crack static growing along an elastic-elastic power law creeping bimaterial interface. For frictional contact of boundary conditions on crack faces, asymptotic solutions of the stresses and strains of near tip-crack are got. It was shown that in stable creep growing phase, elastic deformation and viscous deformation are equally dominant in the near-tip field, the stress and strain have the same singularity and there is not the oscillatory singularity the field. Through numerical calculation , it is shown that the frictional coefficient η notably influence the crack-tip field.展开更多
文摘Purpose:The goal of this study is to analyze the relationship between funded and unfunded papers and their citations in both basic and applied sciences.Design/methodology/approach:A power law model analyzes the relationship between research funding and citations of papers using 831,337 documents recorded in the Web of Science database.Findings:The original results reveal general characteristics of the diffusion of science in research fields:a)Funded articles receive higher citations compared to unfunded papers in journals;b)Funded articles exhibit a super-linear growth in citations,surpassing the increase seen in unfunded articles.This finding reveals a higher diffusion of scientific knowledge in funded articles.Moreover,c)funded articles in both basic and applied sciences demonstrate a similar expected change in citations,equivalent to about 1.23%,when the number of funded papers increases by 1%in journals.This result suggests,for the first time,that funding effect of scientific research is an invariant driver,irrespective of the nature of the basic or applied sciences.Originality/value:This evidence suggests empirical laws of funding for scientific citations that explain the importance of robust funding mechanisms for achieving impactful research outcomes in science and society.These findings here also highlight that funding for scientific research is a critical driving force in supporting citations and the dissemination of scientific knowledge in recorded documents in both basic and applied sciences.Practical implications:This comprehensive result provides a holistic view of the relationship between funding and citation performance in science to guide policymakers and R&D managers with science policies by directing funding to research in promoting the scientific development and higher diffusion of results for the progress of human society.
基金the Major Program of National Natural Science Foundation of China(No.41941019)Shaanxi Province Innovative Talent Promotion Plan-Science and Technology Innovation Team(No.2021TD-55)Central University Natural Science Innovation Team(No.300102262402)。
文摘Combined bodies of rock-like material and rock are widely encountered in geotechnical engineering,such as tunnels and mines.The existing theoretical models describing the stress-strain relationship of a combined body lack a binary feature.Based on effective medium theory,this paper presents the governing equation of the“elastic modulus”for combined and single bodies under triaxial compressive tests.A binary effective medium model is then established.Based on the compressive experiment of concretegranite combined bodies,the feasibility of determining the stress threshold based on crack axial strain is discussed,and the model is verified.The model is further extended to coal-rock combined bodies of more diverse types,and the variation laws of the compressive mechanical parameters are then discussed.The results show that the fitting accuracy of the model with the experimental curves of the concretegranite combined bodies and various types of coal-rock combined bodies are over 95%.The crack axial strain method can replace the crack volumetric strain method,which clarifies the physical meanings of the model parameters.The variation laws of matrix parameters and crack parameters are discussed in depth and are expected to be more widely used in geotechnical engineering.
文摘For a black hole with two horizons, the effective entropy is assumed to be a linear combination of the two entropies of the outer and inner horizons. In terms of the effective thermodynamic quantities the effective Bekenstein-Smarr formula and the effective first law of thermodynamics are derived.
文摘By means of a representation of the elementary objects by the Lagrange density and by the commutators of the communication relations, correlations can be formed using the Fourier transform, which under the conditions of the Hamilton principle, describes correlation structures of the elementary objects with oscillator properties. The correlation structures obtained in this way are characterized by physical information, the essential component of which is the action. The correlation structures describe the physical properties and their interactions under the sole condition of the Hamilton’s principle. The structure, the properties and the interactions of elementary objects can be led back in this way to a fundamental four dimensional structure, which is therefore in their different modifications the building block of nature. With the presented method, an alternative interpretation of elementary physical effects to quantum mechanics is obtained. This report provides an overview of the fundamentals and statements of physical information theory and its consequences for understanding the nature of elementary objects.
文摘This paper explains the Olbers paradox and the origin of cosmic microwave background radiation (CMBR) from the viewpoint of the quantum redshift effect. The derived formula dispels the Olbers paradox, confirming that the CMBR originates from the superposition of light radiated by stars in the whole universe, not the relic of the Big Bang. The dark-night sky and CMBR are all caused by Hubble redshift—the physical mechanism is the quantum redshift of the photon rather than cosmic expansion. So this theory supports the infinite and steady cosmology.
基金Projects(51104059,51204067)supported by the National Natural Science Foundation of ChinaProject(2012CB723103)supported the National Basic Research Program of China+3 种基金Project(IRT1235)supported by Innovation Team Development Plan of the Ministry of Education of ChinaProject(2013M531674)supported by China Postdoctoral Science FoundationProject(132300413203)supported by Basic and Frontier Technology Research Program of Henan Province,ChinaProject(WS2012B07)supported by the Open Project of State Key Laboratory Cultivation Base for Gas Geology and Gas Control(Henan Polytechnic University),China
文摘Focused on the Klinkenberg effect on gas seepage, the independently developed triaxial experimental system of gas seepage was applied to conduct research on the seepage characteristics of coal seam gas. By means of experimental data analysis and theoretical derivation, a calculation method of coal seam gas permeability was proposed, which synthesized the respective influences of gas dynamic viscosity, compressibility factor and Klinkenberg effect. The study results show that the Klinkenberg effect has a significant influence on the coal seam gas seepage, the permeability estimated with the method considering the Klinkenberg effect is correct, and this permeability can fully reflect the true seepage state of the gas. For the gas around the standard conditions, the influences of dynamic viscosity and compressibility factor on the permeability may be ignored. For the gas deviating far away from the standard conditions, the influences of dynamic viscosity and compressibility factor on the permeability must be considered. The research results have certain guiding significance in forming a correct understanding of the Klinkenberg effect and selecting a more accurate calculation method for the permeability of coal containing gas.
基金funded by the Natural Science Foundation of China(Grant No.42077435)。
文摘This article presents a mathematical model for simulating the mechanical behaviour of lightning strikes and analysing the resulting damage to the soil.This article focuses on the electro-thermal effect and seepage caused by lightning strikes in particular.Then,a numerical model based on the conservation laws of momentum,mass and energy is developed for soil subjected to lightning strikes.Comparisons to field observations and theoretical calculations are used to demonstrate the efficacy and accuracy of numerical simulations.The findings demonstrate that lightning strikes can cause soils to experience both seepage force and heat stress.Under the calculative condition of this article:by increasing the intrinsic permeability of the soil,k_(p)(≥10^(-10)m^(2)),the seepage force can be effectively reduced,hence reducing the risk of lightning strikes;improving the electrical conductivity of the soil β(≥10^(-1) S/m^(2))and lowering its thermal expansion coefficient(≤10^(-6)K^(-1))can greatly reduce the damage caused by lightning strikes to the soil.The preceding investigations demonstrate that the suggested model is capable of evaluating mechanical damage caused by lightning in the soil,and the findings contribute to a better understanding of soil mechanical response to lightning strikes.
文摘Using micro-level data from China Employer-Employee Survey(CEES), this paper conducts an empirical analysis of firms' heterogeneous characteristics in the implementation of the Labor Contract Law and its effects on employees. Our findings are as follows: With China's economic development, firms more proactively implement the Labor Contract Law, resulting in a higher percentage of employees with labor contracts. Labor contracts significantly increase the probability of employees in receiving social insurances, such as pension, health, unemployment, work injury and birth insurances, and have a significantly positive effect on wage income. Longer term of labor contract corresponds to stronger employment protection, and such an effect is highly robust. Larger firms with higher capital-labor ratios have better results in implementing the Labor Contract Law. And employees of private and labor-intensive firms have poorer coverage of employment and social protection; such firms should be given focal attention in the law's implementation.
文摘Fe 100- x Ni x alloys of ultrafine particle with the average grain size of about 10 nm were synthesized by mechanically alloying process. The samples were investigated by X ray diffraction and measurements of the saturation magnetization and coercivity force. Both b.c.c and f.c.c phase exist within a wide range for Fe 100- x Ni x , while x ≤45. The effective magnetic anisotropy K e was measured by applying the law of approach to saturation. The value of K e decreases with an increase of Ni content. It is noticed that the strain anisotropy makes a large contribution to the magnetic anisotropy. The estimation of grain size leads to the determination of the single domain critical size and domain wall energy. The exchange stiffness and exchange integral deduced from the relationship between the effective magnetic anisotropy and domain wall energy are in agreement with that calculated by other methods.
文摘The known statistical data show that the distribution of popular elements and people’s income presents the characteristics of power law distribution.At present,the explanation for this phenomenon is mostly through the“rich get richer”theory,but the author believes that this theory has major flaws and fails to provide a reasonable explanation for many phenomena.Therefore,the author expands some empirical and recognized theories in a similar direction in logic,and derives a logical mathematical model through the derivation of mathematical formulas,so as to explain the phenomenon that the distribution of popular elements and people’s income presents a power-law distribution.Then,by analyzing various characteristics of social networks and comparing them with some phenomena in nature,the conclusion can be extended to all self-organizing groups in nature.
文摘Based on the divergence theorem, we reveal that the Fickian first law relevant to the diffusion flux |J(t,x,y,z) > in the time and space is incomplete without an integral constant |J0(t) > for the integral of Fickian second law. The new diffusion flux (NDF) taking it into account shows that we can systematically understand the problems of one-way diffusion, impurity diffusion and self-diffusion as a special case of the interdiffusion. Applying the NDF to the interdiffusion problem between metal plates, it is clarified that the Kirkenkall effect is caused by |J0(t) > and also that the interdiffusion coefficients in alloy can be easily obtained. The interdiffusion problems are reasonably solved regardless of the intrinsic diffusion conception. Thus the NDF to replace the Fickian first law is an essential equation in physics.
文摘The light propagation through system a polarizer-analyzer is investigated on the basis of quantum conceptions about the nature of light. It is shown, that Malus law based on principles of classical electrodynamics not completely takes into account all effects which can occur at the light propagation through system a polarizer-analyzer. The phenomenon of possible change of frequency of light in particular drops out, for example in the region of X-ray radiation. The deduction of Malus law based on quantum principles is given. For comparison the differential effective section of interaction of a photon and electron with take into account of rotation of a plane of polarization of a photon in Compton’s effect is found.
基金supported by Academia Sinica (Taipei) and Science Council (Grant NSC96-2116-M-001-012-MY3).
文摘The two one-state-variable, rate- and state-dependent friction laws, i.e., the slip and slowness laws, are com- pared on the basis of dynamical behavior of a one-degree-of-freedom spring-slider model through numerical simulations. Results show that two (normalized) model parameters, i.e., A (the normalized characteristic slip distance) and β-α (the difference in two normalized parameters of friction laws), control the solutions. From given values of △, β, and α, for the slowness laws, the solution exists and the unique non-zero fixed point is stable when △〉(β-α), yet not when △ 〈(β-α). For the slip law, the solution exists for large ranges of model parameters and the number and stability of the non-zero fixed points change from one case to another. Results suggest that the slip law is more appropriate for controlling earthquake dynamics than the slowness law.
文摘Atmospheric effects on interferometric synthetic aperture radar(InSAR) measurements are quantitatively studied based on a tandem pair of SAR data and a month-long continuous GPS tracking data obtained at six stations. Differential atmospheric signals extracted from the SAR data for two selected areas show apparent power law characteristics. The RMS values of the signals are 2.04 and 3.66 rad respectively for the two areas. These differential delays can potentially cause in the two areas peak-to-peak deformation errors of 3.64 and 6.52cm, respectively, at the 95% confidence level and Gaussian distribution. The respective potential peak-to-peak DEM errors are 123 and 221 m. The GPS tropospheric total zenith delays estimate indicates that a peak-to-peak error of about 7.8cm can potentially be caused in a SAR interferogram with only 1 d interval at the 95% confidence level. The error increases to about 9.6cm for 10 d interval. The potential peak-to-peak DEM and deformation errors estimated from GPS total zenith delay measurements are however quite similar to those estimated from InSAR data. This provides us with a useful tool to pre-estimate the potential atmospheric effects in a SAR interferogram before we order the SAR images. Nevertheless, the results reveal that even in a small area the atmospheric delays can obscure centimetre level ground displacements and introduce a few hundred meters of errors to derived DEM.
基金Projects(20B062,19B054)supported by Excellent Youth Program of Hunan Education Department,ChinaProject(2019JJ50688)supported by Hunan Provincial Natural Science Foundation of ChinaProject(kq195004)supported by Changsha Science and Technology Bureau Project,China。
文摘To study the additional aerodynamic effect on a bridge girder under the action of wind-driven rain, the rainfall similarity considering raindrop impact and surface water is first given. Then, the dynamic characteristics and the process of vortex and flutter generation of the segment models under different rain intensities and angles of attack are tested by considering several typical main girder sections as examples. The test results indicate that the start and end wind speeds,interval length and number of vortex vibrations remain unchanged when it is raining, rainfall will reduce the windinduced vortex response. When test rain intensity is large, the decrease of amplitude is obvious. However, after considering the rain intensity similarity in this study, all of actual maximum rain intensities after conversion approach the domestic extreme rain intensity of approximately 709 mm/h. It can be observed that rainfall has a limited influence on the dynamic characteristics of the structure and vortex vibration response. When the test rain intensity is 120 mm/h, the critical wind speed of the model flutter increases by 20%-30%. However, after considering the rain intensity similarity ratio, the influence of rainfall on the wind-induced flutter instability of the bridge girder may be ignored.
基金Projects(51323014,51479097,51279086)supported by the National Natural Science Foundation of ChinaProject(2016-KY-2)supported by the State Key Laboratory of Hydroscience and Hydraulic Engineering,China
文摘Reservoir impoundment is related to several hydraulic engineering concerns,including irreversible valley contractions,landslides and reservoir-induced earthquakes.However,these phenomena,such as valley contractions,are hardly to be explained by the conventional method.The scientific understanding of water effects during impoundment and their hazards to hydraulic structure are needed.The effective stress law for fissured rock masses is introduced in the elasto-plastic model employing the Drucker-Prager criterion and implemented in the three dimension(3D)nonlinear finite element method(FEM)program Three-dimensional FINite Element(TFINE).The slope deforms towards river-way during impoundment since the increasing pore pressure in fissures changes stress state and leads to additional plastic deformation in the rock materials.The value of Biot coefficient and the influence of water on rock materials are discussed in detail.Thus,the mechanism of slope deformation during the impoundment of Jinping-I arch dam is revealed,and the deformation is accurately measured.The application of the effective stress law provides a method to consider stress assessment,deformation evaluation and stability estimate of hydraulic structures during the impoundment process.This is a beneficial exploration and an improvement of hydraulic engineering design.
文摘This paper presents a novel idea of utilizing the reactional torque of the conventional electric motor as a linear output for propulsion in addition to the conventional torque output of the rotor. The idea is demonstrated by a theoretical proposal of linearizing the stator of one of the most used motors </span><span style="font-family:Verdana;">in Electrical Vehicles and Hybrid Vehicles</span><span style="font-family:""><span style="font-family:Verdana;">. The proposed Linear Stator Motor is a </span><span style="font-family:Verdana;">simple modification without involving any functional change of the conventional motor. Though theoretical, the indicated possible input </span><span style="font-family:Verdana;">energy saving of more than 75% as compared to the conventional motor is no surprise, as by linearizing the stator, an almost equal linear propulsion output is added to the conventional rotor output. In addition to this remarkable saving in input energy, the proposed Linear Stator Motor that suits all type</span></span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> of vehicle</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;">, can maintain propulsion without the need for a mechanical transmission system. Also, in </span><span style="font-family:Verdana;">the </span><span style="font-family:Verdana;">case of watercraft and aircraft vehicles, no external mechanical propulsion drive system is required. It is just an internal force that can push the vehicle forward, backward</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> or laterally, while the conventional rotor output can be utilized for energy recovery by driving a DC generator.
基金supported by the National Natural Science Foundation of China(Grant Nos.51871161 and 52071233)。
文摘Epitaxial Mn_(4)N films with different thicknesses were fabricated by facing-target reactive sputtering and their anomalous Hall effect(AHE)is investigated systematically.The Hall resistivity shows a reversed magnetic hysteresis loop with the magnetic field.The magnitude of the anomalous Hall resistivity sharply decreases with decreasing temperature from300 K to 150 K.The AHE scaling law in Mn_(4)N films is influenced by the temperature-dependent magnetization,carrier concentration and interfacial scattering.Different scaling laws are used to distinguish the various contributions of AHE mechanisms.The scaling exponentγ>2 for the conventional scaling in Mn_(4)N films could be attributed to the residual resistivityρ_(xx0).The longitudinal conductivityσ_(xx)falls into the dirty regime.The scaling ofρ_(AH)=αρ_(xx0)+bρ_(xx)~nis used to separate out the temperature-independentρ_(xx0)from extrinsic contribution.Moreover,the relationship betweenρ_(AH)and pxx is fitted by the proper scaling to clarify the contributions from extrinsic and intrinsic mechanisms of AHE,which demonstrates that the dominant mechanism of AHE in the Mn4 N films can be ascribed to the competition between skew scattering,side jump and the intrinsic mechanisms.
文摘The three most common variations of Fitts’ index of difficulty are the Fitts formulation, the Welford formulation, and the Shannon formulation. A recent paper by Hoffmann [1] critiqued the three and concluded that the Fitts and Welford formulations are valid and that the Shannon formulation is invalid. In this paper, we challenge Hoffmann’s position regarding the Shannon formulation. It is argued that the issue of validity vs. invalidity is ill-conceived, given that Fitts’ law is a “model by analogy” with no basis in human motor control. The relevant questions are of utility: Does a model work? How well? Is it useful? Where alternative formulations exist, they may be critiqued and compared for strengths and weaknesses, but validity is an irrelevant construct. In a reanalysis of data from Fitts’ law experiments, models built using the Shannon formulation are (re)affirmed to be as good as, and generally better than, those built using the Fitts or Welford formulation.
基金the Natural Science Foundation of Heilongjiang Province(A009).
文摘A mechanical model is established for mode II interfacial crack static growing along an elastic-elastic power law creeping bimaterial interface. For frictional contact of boundary conditions on crack faces, asymptotic solutions of the stresses and strains of near tip-crack are got. It was shown that in stable creep growing phase, elastic deformation and viscous deformation are equally dominant in the near-tip field, the stress and strain have the same singularity and there is not the oscillatory singularity the field. Through numerical calculation , it is shown that the frictional coefficient η notably influence the crack-tip field.