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 calculate the long-range Van der Waals force and the photoelectric cross section in a noncommutative setup. It is argued that non-commutativity effects could not be discerned for the Van der Waals interactions. The...We calculate the long-range Van der Waals force and the photoelectric cross section in a noncommutative setup. It is argued that non-commutativity effects could not be discerned for the Van der Waals interactions. The result for the photoelectric effect shows deviation from the usual commutative one, which in principle can be used to put bounds on the space-space non-commutativity parameter.展开更多
This study aims to produce 229Th using an innovative nuclear reactor concept,i.e.,accelerator-driven system(ADS)reactor.Herein,we investigated the feasibility of producing 229Th from neutron transmutation of 226Ra to ...This study aims to produce 229Th using an innovative nuclear reactor concept,i.e.,accelerator-driven system(ADS)reactor.Herein,we investigated the feasibility of producing 229Th from neutron transmutation of 226Ra to expand the availability of 225Ac and 213Bi in a simple model of ADS reactor.ADS reactor comprises two zones,i.e.,an inner zone with a fast neutron spectrum and outer zone with thermal neutron spectrum,which is a subcritical core coupled with an external neutron source.Transmutation behavior,activity,and mass ratio of the obtained isotopes were investigated using the Monte-Carlo tool.In addition with offering the capability,flexibility,and safety of radioactive waste transmutation,the proposed ADS model provides high 229Th yield and requires less time than a critical reactor with the same neutron flux and irradiated quantity of 226Ra.展开更多
Radiation for targeting liver tumors can be challenging because of the damage that it can cause to sensitive organs such as heart and kidney.To calculate the dose received by noninvolved organs,a modeling of the pati...Radiation for targeting liver tumors can be challenging because of the damage that it can cause to sensitive organs such as heart and kidney.To calculate the dose received by noninvolved organs,a modeling of the patient’s entire body is necessary.Therefore,in this study,a human Oak Ridge National Laboratory-Medical Internal Radiation Dose phantom was used for liver proton therapy simulation.The results show that the optimum proton energy interval covering the whole tumor was in the range of 90-120 MeV.A spread-out Bragg peak was built by adding Bragg peaks to cover the liver tumor volume,and beam parameters recommended by the International Commission on Radiation Units and Measurements(ICRU) were evaluated.The flux of secondary particles was calculated on the surface of the tumor,and two-dimensional dose distributions for protons,neutrons and photons were shown.Finally,the total doses of protons,photons and neutrons in tumor and 14 noninvolved organs were calculated.The results indicated that the ratio of received dose to the normal tissue of the liver concerning the spherical tumor of 2 cm in radius was approximately0.01.This ratio for organs such as gall bladder,heart and kidney was approximately 8.4×10-5,5.1×10-5 and2.34×10-5.Secondary particles such as neutrons andphotons deposit their energies to organs located far from the treatment volume,thus increasing the risk of secondary cancers.The research results indicated that the secondary particles dose was quite small in liver proton therapy.All the calculations were performed using Monte Carlo N-Particle Transport Code (MCNP).展开更多
Data is becoming increasingly personal.Individuals regularly interact with a variety of structured data,ranging from SQLite databases on the phone to personal sensors and open government data.The“digital traces left ...Data is becoming increasingly personal.Individuals regularly interact with a variety of structured data,ranging from SQLite databases on the phone to personal sensors and open government data.The“digital traces left by individuals through these interactions”are sometimes referred to as“small data”.Examples of“small data”include driving records,biometric measurements,search histories,weather forecasts and usage alerts.In this paper,we present a flexible protocol called LoRaCTP,which is based on LoRa technology that allows data“chunks”to be transferred over large distances with very low energy expenditure.LoRaCTP provides all the mechanisms necessary to make LoRa transfer reliable by introducing a lightweight connection setup and allowing the ideal sending of an as-long-as necessary data message.We designed this protocol as communication support for small-data edge-based IoT solutions,given its stability,low power usage,and the possibility to cover long distances.We evaluated our protocol using various data content sizes and communication distances to demonstrate its performance and reliability.展开更多
We study the energy levels of the hydrogen atom in the noncommutative phase space with simultaneous spacespace and momentum-momentum noncommutative relations, We find new terms compared to the case that only noncommut...We study the energy levels of the hydrogen atom in the noncommutative phase space with simultaneous spacespace and momentum-momentum noncommutative relations, We find new terms compared to the case that only noncommutative space-space relations are assumed. We also present some comments on a previous paper [Alavi S A hep-th/0501215].展开更多
The similarity between classical and quantum physics is large enough to make an investigation of quantization methods a worthwhile endeavour. As history has shown, Dirac's canonical quantization method works reaso...The similarity between classical and quantum physics is large enough to make an investigation of quantization methods a worthwhile endeavour. As history has shown, Dirac's canonical quantization method works reasonably well in the case of conventional quantum mechanics over R<sup>n</sup> but it may fail in non-trivial phase spaces and also suffer from ordering problems. Affine quantization is an alternative method, similar to the canonical quantization, that may offer a positive result in situations for which canonical quantization fails. In this paper we revisit the affine quantization method on the half-line. We formulate and solve some simple models, the free particle and the harmonic oscillator.展开更多
Soil and water conservation is essential for sustaining food production and for preserving the environment in arid and semi arid lands （ASALs） where conditions for agriculture and other land use systems are often ha...Soil and water conservation is essential for sustaining food production and for preserving the environment in arid and semi arid lands （ASALs） where conditions for agriculture and other land use systems are often harsh and unpredictable. The ASALs of Algeria are an important source of a variety of non wood forest products like Stipa tenacissima L. plant （esparto grass）. This research was conducted to determine the effects of different low concentration （〈 I%） polyacrylaJnide, Stipa tenacissima L. fiber （esparto grass fibers） and its mixtures with the polymer at water retention in arid and semi arid soil. All samples are characterized by infrared spectroscopy, X-ray Diffractometry, thermal analysis TG DSC and scanning electron micrographs （SEM）. The results showed that polymer blend in soil could improve better soil physical proprieties decreased evaporation and increase water retention in arid soils compared with application of any other blend at the same concentration. The use of Polyacrylamide-Cellulose blend appears to promise for reducing the labor cost of irrigation at arid and semi-arid soils, and offers safe and environmentally friendly inexpensive materials. The importance of Polyacrylamide-Cellulose blends to alleviate poor physical properties and retain water in these arid regions to sustain plant growth.展开更多
The He-McKellar-Wilkens （HMW） effect in non-commutative （NC） space is studied. By solving the Dirac equations on NC space, we obtain topological HMW phase in NC space where the additional terms related to the spac...The He-McKellar-Wilkens （HMW） effect in non-commutative （NC） space is studied. By solving the Dirac equations on NC space, we obtain topological HMW phase in NC space where the additional terms related to the space non-commutativity are given explicitly.展开更多
With the increasing number of applications of Global navigation satellite system, the modeling of the ionosphere is a crucial element for precise positioning. Indeed, the ionosphere delays the electromagnetic waves wh...With the increasing number of applications of Global navigation satellite system, the modeling of the ionosphere is a crucial element for precise positioning. Indeed, the ionosphere delays the electromagnetic waves which pass through it and induces a delay of propagation related to the electronic density (TEC) Total Electronic Content and to the frequency of the wave. The impact of this ionospheric error often results in a poor determination of the station’s position, particularly in strong solar activity. The first part of this paper focuses on a bibliographic study oriented first of all on the study of the ionosphere in relation to solar activity and secondly on the determination of the total electron content using GNSS measurements from the IGS network reference stations. Measurements were made on two permanent stations “RABT”, “TETN”. We selected years of GNSS measurements to evaluate the geomagnetic impact on the ionosphere, 2001, 2009 and 2013. A description of the ionospheric disturbances and geomagnetic storms was analyzed by determination of TEC, especially in high solar activity. The results show a strong dependence of the ionospheric activity with the geomagnetic activity.展开更多
Statistical behavior of a classical φ4 Hamiltonian lattice is investigated from microscopic dynamics. Thelargest Lyapunov exponent and entropies are considered for manifesting chaos and equipartition behaviors of the...Statistical behavior of a classical φ4 Hamiltonian lattice is investigated from microscopic dynamics. Thelargest Lyapunov exponent and entropies are considered for manifesting chaos and equipartition behaviors of the system.It is found, for the first time, that for any large while finite system size there exist two critical couplings for the transitionsto equipartitions, and the scaling behaviors of these lower and upper critical couplings vs. the system size are numericallyobtained.展开更多
In the new framework of gravitational quantum field theory(GQFT) with spin and scaling gauge invariance developed in Phys. Rev. D 93(2016) 024012-1, we make a perturbative expansion for the full action in a background...In the new framework of gravitational quantum field theory(GQFT) with spin and scaling gauge invariance developed in Phys. Rev. D 93(2016) 024012-1, we make a perturbative expansion for the full action in a background field which accounts for the early inflationary universe. We decompose the bicovariant vector fields of gravifield and spin gauge field with Lorentz and spin symmetries SO(1,3) and SP(1,3) in biframe spacetime into SO(3) representations for deriving the propagators of the basic quantum fields and extract their interaction terms. The leading order Feynman rules are presented. A tree-level 2 to 2 scattering amplitude of the Dirac fermions, through a gravifield and a spin gauge field, is calculated and compared to the Born approximation of the potential. It is shown that the Newton's gravitational law in the early universe is modified due to the background field. The spin dependence of the gravitational potential is demonstrated.展开更多
We stress a basic criterion that shows in a simple way how a sequence of real-valued functions can converge uniformly when it is more or less evident that the sequence converges uniformly away from a finite number of ...We stress a basic criterion that shows in a simple way how a sequence of real-valued functions can converge uniformly when it is more or less evident that the sequence converges uniformly away from a finite number of points of the closure of its domain. For functions of a real variable, unlike in most classical textbooks our criterion avoids the search of extrema (by differential calculus) of their general term.展开更多
Critical dynamics of the random Ising model with long-range interaction decaying as r-(d+σ) where d is the dimensionality) is studied by the theoretic renormalization-group approach. The system is released to an evol...Critical dynamics of the random Ising model with long-range interaction decaying as r-(d+σ) where d is the dimensionality) is studied by the theoretic renormalization-group approach. The system is released to an evolution within a model A dynamics. Asymptotic scaling laws are studied in a frame of the expansion in = 2σ - d. In dimensions d ＜ 2σ. the dynamic exponent z is calculated to the second order in at the random fixed point.展开更多
Morphostructural nodes in North Vietnam are delineated with the morphostructural zoning （MZ） method, and classified into seismogenic and non-seismogenic nodes. The compiled morphostructural map （ scale 1 ： 1000000...Morphostructural nodes in North Vietnam are delineated with the morphostructural zoning （MZ） method, and classified into seismogenic and non-seismogenic nodes. The compiled morphostructural map （ scale 1 ： 1000000） shows a three-level hierarchical structure of blocks, boundary zones, and nodes. The identified nodes are classified with the pattern-recognition algorithm CORA-3 into those that are prone to generate M≥5.0 earthquakes and those that are not. Some of the earthquake-prone nodes coincide with epicenters of M ≥ 5.0 earthquakes that have occurred ; others may coincide with such events in the future.展开更多
The aim of this paper is the introduction of a new approach to 3D modelling of elastic piecewise homogeneous media, in particular Earth crust and upper Mantle. The method is based on the principle of tomography with E...The aim of this paper is the introduction of a new approach to 3D modelling of elastic piecewise homogeneous media, in particular Earth crust and upper Mantle. The method is based on the principle of tomography with Earthquake as a source of the signal and receiver stations on the surface. The wave propagation in solid media is described by a system of three strongly coupled hyperbolic equations with piece - wise constant coefitients. The characteristic set and hi-characteristic curves of this system are computed in a homogeneous half-space with free boundary and the formulae of reflection and diffraction of the hi-characteristics on the internal boundaries of the media. Applications of the characteristic set and bi-eharacteristic curves for the inverse problem in geophysics and Earth modelling are given.展开更多
Objectives To investigate serum concentration of procollagen type Icarboxyterminal peptide (PⅠP), type Ⅲ aminopeptide (PⅢP) and type Icollagen telopeptide (ICTP) in essential hypertension (EH). Methods Serum levels...Objectives To investigate serum concentration of procollagen type Icarboxyterminal peptide (PⅠP), type Ⅲ aminopeptide (PⅢP) and type Icollagen telopeptide (ICTP) in essential hypertension (EH). Methods Serum levels of PⅠP, PⅢP and ICTP in 42 EH patients and 30 healthy control were measured by radioimmunoassays. Results In EH patients, serum concentration of PⅠP, PⅢP was significantly higher than that in 30 healthy control. Although EH patients did tend to exhibit a higher serum ICTP concentration than normal control subjects, the difference was not statistically significant. EH patients with left ventricular hypertrophy exhibited higher values of PⅠP (P < 0. 05) and lower values of ICTP (P < 0. 05) than EH patients without left ventricular hypertrophy. No significant difference was noted between the serum PⅢP of the EH patients with and without left ventricular hypertrophy (P > 0.05 ). Conclusions The results suggest that PⅠP and PⅢP are sensitive serum markers of myocardial collagen synthesis. Myocardial fibrosis may be due to the excessive synthesis and insufficient degradation of collagen. PⅠP, PⅢP and ICTP may be indirect markers of myocardial fibrosis.展开更多
In this study,Mn_(3)O_(4) spherical particles(SPs)were synthesized by the sol-gel process,after which they were thermally annealed at 400℃,and comprehensively characterized.X-ray Diffraction(XRD)revealed that Mn_(3)O...In this study,Mn_(3)O_(4) spherical particles(SPs)were synthesized by the sol-gel process,after which they were thermally annealed at 400℃,and comprehensively characterized.X-ray Diffraction(XRD)revealed that Mn_(3)O_(4) exhibited a tetragonal spinel structure,and Fourier transformed infrared(FTIR)spectroscopy identified surfaceadsorbed functional groups.Scanning electron microscopy(SEM)and the specific surface area analyses by Brunauer−Emmett−Teller(BET)revealed a porous,homogeneous surface composed of strongly agglomerated spherical grains with an estimated average particle size of∼35 nm,which corresponded to a large specific surface area of∼81.5 m^(2)/g.X-ray photoelectron spectroscopy(XPS)analysis indicated that Mn_(3)O_(4) was composed of metallic cations(Mn^(4+),Mn^(3)+,and Mn^(2+))and oxygen species(O_(2)−,OH−and CO_(3)^(2−)).The optical bandgap energy is∼2.55 eV.Assessment of the catalytic performance of the Mn_(3)O_(4) SPs indicated T90 conversion of CH4 to CO_(2) and H_(2)O at 398℃ for gas hourly space velocity(GHSV)of 72000 mL^(3) g^(−1) h^(−1).This observed performance can be attributed to the cooperative effects of the smallest spherical grain size with a mesoporous structure,which is responsible for the larger specific surface area and available surface-active oxygenated species.The cooperative effect of the good reducibility,higher ratio of active species(OLat/OAds),and results of density functional theory(DFT)calculations suggested that the total oxidation of CH_(4) over the mesoporous Mn_(3)O_(4) SPs might take place via a two-term process in which both the Langmuir−Hinshelwood and Mars−van Krevelen mechanisms are cooperatively involved.展开更多
We consider a new cosmological model(calledΛCDM),in which the vacuum energy interacts with matter and radiation,and test this model using the current cosmological observations.Using the CMB+BAO+SN(CBS)dataset to cons...We consider a new cosmological model(calledΛCDM),in which the vacuum energy interacts with matter and radiation,and test this model using the current cosmological observations.Using the CMB+BAO+SN(CBS)dataset to constrain the model,we find that H_(0) and S_(8) tensions are relieved to 2.87σand 2.77σ,respectively.However,in this case,theΛCDM model is not favored by the data,compared withΛCDM.We find that when the H_(0) and S_(8) data are added to the data combination,the situation is significantly improved.In the CBS+H_(0) case,the model relieves the H_(0) tension to 0.47σ,and the model is favored overΛCDM.In the CBS+H_(0)+S_(8) case,we obtain a synthetically best situation,in which the H_(0) and S_(8) tensions are relieved to 0.72σand 2.11σ,respectively.In this case,the model is most favored by the data.Therefore,this cosmological model can greatly relieve the H_(0) tension and simultaneously effectively alleviate the S_(8) tension.展开更多
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 under Grant No 10575026.
文摘We calculate the long-range Van der Waals force and the photoelectric cross section in a noncommutative setup. It is argued that non-commutativity effects could not be discerned for the Van der Waals interactions. The result for the photoelectric effect shows deviation from the usual commutative one, which in principle can be used to put bounds on the space-space non-commutativity parameter.
基金supported by the International Center for Theoretical Physics and the Institute of International Education’s Scholar Rescue Fund.
文摘This study aims to produce 229Th using an innovative nuclear reactor concept,i.e.,accelerator-driven system(ADS)reactor.Herein,we investigated the feasibility of producing 229Th from neutron transmutation of 226Ra to expand the availability of 225Ac and 213Bi in a simple model of ADS reactor.ADS reactor comprises two zones,i.e.,an inner zone with a fast neutron spectrum and outer zone with thermal neutron spectrum,which is a subcritical core coupled with an external neutron source.Transmutation behavior,activity,and mass ratio of the obtained isotopes were investigated using the Monte-Carlo tool.In addition with offering the capability,flexibility,and safety of radioactive waste transmutation,the proposed ADS model provides high 229Th yield and requires less time than a critical reactor with the same neutron flux and irradiated quantity of 226Ra.
文摘Radiation for targeting liver tumors can be challenging because of the damage that it can cause to sensitive organs such as heart and kidney.To calculate the dose received by noninvolved organs,a modeling of the patient’s entire body is necessary.Therefore,in this study,a human Oak Ridge National Laboratory-Medical Internal Radiation Dose phantom was used for liver proton therapy simulation.The results show that the optimum proton energy interval covering the whole tumor was in the range of 90-120 MeV.A spread-out Bragg peak was built by adding Bragg peaks to cover the liver tumor volume,and beam parameters recommended by the International Commission on Radiation Units and Measurements(ICRU) were evaluated.The flux of secondary particles was calculated on the surface of the tumor,and two-dimensional dose distributions for protons,neutrons and photons were shown.Finally,the total doses of protons,photons and neutrons in tumor and 14 noninvolved organs were calculated.The results indicated that the ratio of received dose to the normal tissue of the liver concerning the spherical tumor of 2 cm in radius was approximately0.01.This ratio for organs such as gall bladder,heart and kidney was approximately 8.4×10-5,5.1×10-5 and2.34×10-5.Secondary particles such as neutrons andphotons deposit their energies to organs located far from the treatment volume,thus increasing the risk of secondary cancers.The research results indicated that the secondary particles dose was quite small in liver proton therapy.All the calculations were performed using Monte Carlo N-Particle Transport Code (MCNP).
基金supported by the“Conselleria de Innovación,Universidades,Ciencia y Sociedad Digital”,Proyectos AICO/2020Spain,under Grant AICO/2020/302 and“Ministerio de Ciencia,Innovación y Universidades,Programa Estatal de Investigación,Desarrollo e Innovación Orientada a los Retos de la Sociedad,Proyectos I+D+I 2018”Spain,under Grant RTI2018-096384-B-I00.
文摘Data is becoming increasingly personal.Individuals regularly interact with a variety of structured data,ranging from SQLite databases on the phone to personal sensors and open government data.The“digital traces left by individuals through these interactions”are sometimes referred to as“small data”.Examples of“small data”include driving records,biometric measurements,search histories,weather forecasts and usage alerts.In this paper,we present a flexible protocol called LoRaCTP,which is based on LoRa technology that allows data“chunks”to be transferred over large distances with very low energy expenditure.LoRaCTP provides all the mechanisms necessary to make LoRa transfer reliable by introducing a lightweight connection setup and allowing the ideal sending of an as-long-as necessary data message.We designed this protocol as communication support for small-data edge-based IoT solutions,given its stability,low power usage,and the possibility to cover long distances.We evaluated our protocol using various data content sizes and communication distances to demonstrate its performance and reliability.
基金Supported by the National Natural Science Foundation of China under Grant Nos 90303003 and 10575026, and the Natural Science Foundation of Zhejiang Province of China （M103042）.
文摘We study the energy levels of the hydrogen atom in the noncommutative phase space with simultaneous spacespace and momentum-momentum noncommutative relations, We find new terms compared to the case that only noncommutative space-space relations are assumed. We also present some comments on a previous paper [Alavi S A hep-th/0501215].
文摘The similarity between classical and quantum physics is large enough to make an investigation of quantization methods a worthwhile endeavour. As history has shown, Dirac's canonical quantization method works reasonably well in the case of conventional quantum mechanics over R<sup>n</sup> but it may fail in non-trivial phase spaces and also suffer from ordering problems. Affine quantization is an alternative method, similar to the canonical quantization, that may offer a positive result in situations for which canonical quantization fails. In this paper we revisit the affine quantization method on the half-line. We formulate and solve some simple models, the free particle and the harmonic oscillator.
文摘Soil and water conservation is essential for sustaining food production and for preserving the environment in arid and semi arid lands （ASALs） where conditions for agriculture and other land use systems are often harsh and unpredictable. The ASALs of Algeria are an important source of a variety of non wood forest products like Stipa tenacissima L. plant （esparto grass）. This research was conducted to determine the effects of different low concentration （〈 I%） polyacrylaJnide, Stipa tenacissima L. fiber （esparto grass fibers） and its mixtures with the polymer at water retention in arid and semi arid soil. All samples are characterized by infrared spectroscopy, X-ray Diffractometry, thermal analysis TG DSC and scanning electron micrographs （SEM）. The results showed that polymer blend in soil could improve better soil physical proprieties decreased evaporation and increase water retention in arid soils compared with application of any other blend at the same concentration. The use of Polyacrylamide-Cellulose blend appears to promise for reducing the labor cost of irrigation at arid and semi-arid soils, and offers safe and environmentally friendly inexpensive materials. The importance of Polyacrylamide-Cellulose blends to alleviate poor physical properties and retain water in these arid regions to sustain plant growth.
基金Supported in part by the National Natural Science Foundation of China under Grant Nos 10447005 and 10575026, the Natural Science Foundation of Zhejiang Provence under Grant No M103042, and the Abdus Salam ICTP, Trieste, Italy.
文摘The He-McKellar-Wilkens （HMW） effect in non-commutative （NC） space is studied. By solving the Dirac equations on NC space, we obtain topological HMW phase in NC space where the additional terms related to the space non-commutativity are given explicitly.
文摘With the increasing number of applications of Global navigation satellite system, the modeling of the ionosphere is a crucial element for precise positioning. Indeed, the ionosphere delays the electromagnetic waves which pass through it and induces a delay of propagation related to the electronic density (TEC) Total Electronic Content and to the frequency of the wave. The impact of this ionospheric error often results in a poor determination of the station’s position, particularly in strong solar activity. The first part of this paper focuses on a bibliographic study oriented first of all on the study of the ionosphere in relation to solar activity and secondly on the determination of the total electron content using GNSS measurements from the IGS network reference stations. Measurements were made on two permanent stations “RABT”, “TETN”. We selected years of GNSS measurements to evaluate the geomagnetic impact on the ionosphere, 2001, 2009 and 2013. A description of the ionospheric disturbances and geomagnetic storms was analyzed by determination of TEC, especially in high solar activity. The results show a strong dependence of the ionospheric activity with the geomagnetic activity.
文摘Statistical behavior of a classical φ4 Hamiltonian lattice is investigated from microscopic dynamics. Thelargest Lyapunov exponent and entropies are considered for manifesting chaos and equipartition behaviors of the system.It is found, for the first time, that for any large while finite system size there exist two critical couplings for the transitionsto equipartitions, and the scaling behaviors of these lower and upper critical couplings vs. the system size are numericallyobtained.
基金Supported in part by the National Science Foundation of China(NSFC)under Grant Nos.11690022 and 11475237Strategic Priority Research Program of the Chinese Academy of Sciences(CAS), under Grant No.XDB23030100+1 种基金Key Research Program QYZDYSSWSYS007the CAS Center for Excellence in Particle Physics(CCEPP)
文摘In the new framework of gravitational quantum field theory(GQFT) with spin and scaling gauge invariance developed in Phys. Rev. D 93(2016) 024012-1, we make a perturbative expansion for the full action in a background field which accounts for the early inflationary universe. We decompose the bicovariant vector fields of gravifield and spin gauge field with Lorentz and spin symmetries SO(1,3) and SP(1,3) in biframe spacetime into SO(3) representations for deriving the propagators of the basic quantum fields and extract their interaction terms. The leading order Feynman rules are presented. A tree-level 2 to 2 scattering amplitude of the Dirac fermions, through a gravifield and a spin gauge field, is calculated and compared to the Born approximation of the potential. It is shown that the Newton's gravitational law in the early universe is modified due to the background field. The spin dependence of the gravitational potential is demonstrated.
文摘We stress a basic criterion that shows in a simple way how a sequence of real-valued functions can converge uniformly when it is more or less evident that the sequence converges uniformly away from a finite number of points of the closure of its domain. For functions of a real variable, unlike in most classical textbooks our criterion avoids the search of extrema (by differential calculus) of their general term.
文摘Critical dynamics of the random Ising model with long-range interaction decaying as r-(d+σ) where d is the dimensionality) is studied by the theoretic renormalization-group approach. The system is released to an evolution within a model A dynamics. Asymptotic scaling laws are studied in a frame of the expansion in = 2σ - d. In dimensions d ＜ 2σ. the dynamic exponent z is calculated to the second order in at the random fixed point.
文摘Morphostructural nodes in North Vietnam are delineated with the morphostructural zoning （MZ） method, and classified into seismogenic and non-seismogenic nodes. The compiled morphostructural map （ scale 1 ： 1000000） shows a three-level hierarchical structure of blocks, boundary zones, and nodes. The identified nodes are classified with the pattern-recognition algorithm CORA-3 into those that are prone to generate M≥5.0 earthquakes and those that are not. Some of the earthquake-prone nodes coincide with epicenters of M ≥ 5.0 earthquakes that have occurred ; others may coincide with such events in the future.
文摘The aim of this paper is the introduction of a new approach to 3D modelling of elastic piecewise homogeneous media, in particular Earth crust and upper Mantle. The method is based on the principle of tomography with Earthquake as a source of the signal and receiver stations on the surface. The wave propagation in solid media is described by a system of three strongly coupled hyperbolic equations with piece - wise constant coefitients. The characteristic set and hi-characteristic curves of this system are computed in a homogeneous half-space with free boundary and the formulae of reflection and diffraction of the hi-characteristics on the internal boundaries of the media. Applications of the characteristic set and bi-eharacteristic curves for the inverse problem in geophysics and Earth modelling are given.
文摘Objectives To investigate serum concentration of procollagen type Icarboxyterminal peptide (PⅠP), type Ⅲ aminopeptide (PⅢP) and type Icollagen telopeptide (ICTP) in essential hypertension (EH). Methods Serum levels of PⅠP, PⅢP and ICTP in 42 EH patients and 30 healthy control were measured by radioimmunoassays. Results In EH patients, serum concentration of PⅠP, PⅢP was significantly higher than that in 30 healthy control. Although EH patients did tend to exhibit a higher serum ICTP concentration than normal control subjects, the difference was not statistically significant. EH patients with left ventricular hypertrophy exhibited higher values of PⅠP (P < 0. 05) and lower values of ICTP (P < 0. 05) than EH patients without left ventricular hypertrophy. No significant difference was noted between the serum PⅢP of the EH patients with and without left ventricular hypertrophy (P > 0.05 ). Conclusions The results suggest that PⅠP and PⅢP are sensitive serum markers of myocardial collagen synthesis. Myocardial fibrosis may be due to the excessive synthesis and insufficient degradation of collagen. PⅠP, PⅢP and ICTP may be indirect markers of myocardial fibrosis.
基金S.K.acknowledges computing time granted by the Center for Computational Sciences and Simulation(CCSS)the Universität DuisburgEssen and provided on the supercomputer magnitude(DFG grants INST 20876/209-1 FUGG,INST 20876/243-1 FUGG)the Zentrum für Informations-und Mediendienste(ZIM).S.K.gratefully acknowledges the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)for funding 388390466-TRR 247.
文摘In this study,Mn_(3)O_(4) spherical particles(SPs)were synthesized by the sol-gel process,after which they were thermally annealed at 400℃,and comprehensively characterized.X-ray Diffraction(XRD)revealed that Mn_(3)O_(4) exhibited a tetragonal spinel structure,and Fourier transformed infrared(FTIR)spectroscopy identified surfaceadsorbed functional groups.Scanning electron microscopy(SEM)and the specific surface area analyses by Brunauer−Emmett−Teller(BET)revealed a porous,homogeneous surface composed of strongly agglomerated spherical grains with an estimated average particle size of∼35 nm,which corresponded to a large specific surface area of∼81.5 m^(2)/g.X-ray photoelectron spectroscopy(XPS)analysis indicated that Mn_(3)O_(4) was composed of metallic cations(Mn^(4+),Mn^(3)+,and Mn^(2+))and oxygen species(O_(2)−,OH−and CO_(3)^(2−)).The optical bandgap energy is∼2.55 eV.Assessment of the catalytic performance of the Mn_(3)O_(4) SPs indicated T90 conversion of CH4 to CO_(2) and H_(2)O at 398℃ for gas hourly space velocity(GHSV)of 72000 mL^(3) g^(−1) h^(−1).This observed performance can be attributed to the cooperative effects of the smallest spherical grain size with a mesoporous structure,which is responsible for the larger specific surface area and available surface-active oxygenated species.The cooperative effect of the good reducibility,higher ratio of active species(OLat/OAds),and results of density functional theory(DFT)calculations suggested that the total oxidation of CH_(4) over the mesoporous Mn_(3)O_(4) SPs might take place via a two-term process in which both the Langmuir−Hinshelwood and Mars−van Krevelen mechanisms are cooperatively involved.
基金Supported by the National SKA Program of China(2022SKA0110200,2022SKA0110203)the National Natural Science Foundation of China(11975072,11875102,11835009)。
文摘We consider a new cosmological model(calledΛCDM),in which the vacuum energy interacts with matter and radiation,and test this model using the current cosmological observations.Using the CMB+BAO+SN(CBS)dataset to constrain the model,we find that H_(0) and S_(8) tensions are relieved to 2.87σand 2.77σ,respectively.However,in this case,theΛCDM model is not favored by the data,compared withΛCDM.We find that when the H_(0) and S_(8) data are added to the data combination,the situation is significantly improved.In the CBS+H_(0) case,the model relieves the H_(0) tension to 0.47σ,and the model is favored overΛCDM.In the CBS+H_(0)+S_(8) case,we obtain a synthetically best situation,in which the H_(0) and S_(8) tensions are relieved to 0.72σand 2.11σ,respectively.In this case,the model is most favored by the data.Therefore,this cosmological model can greatly relieve the H_(0) tension and simultaneously effectively alleviate the S_(8) tension.
