Based on ERA5 reanalysis data,the present study analyzed the thermal energy development mechanism and kinetic energy conversion characteristics of two extreme rainstorm processes in relation to the shallow southwest v...Based on ERA5 reanalysis data,the present study analyzed the thermal energy development mechanism and kinetic energy conversion characteristics of two extreme rainstorm processes in relation to the shallow southwest vortex in the warm-sector during a“rain-generated vortex”process and the deep southwest vortex in a“vortex-generated rain”process.The findings were as follows:(1)During the extreme rainstorm on August 11,2020(hereinafter referred to as the“8·11”process),intense surface heating and a high-energy unstable environment were observed.The mesoscale convergence system triggered convection to produce heavy rainfall,and the release of latent condensation heat generated by the rainfall promoted the formation of a southwest vortex.The significant increase(decrease)in atmospheric diabatic heating and kinetic energy preceded the increase(decrease)in vorticity.By contrast,the extreme rainstorm on August 16,2020(hereinafter referred to as the“8·16”process)involved the generation of southwest vortex in a low-energy and highhumidity environment.The dynamic uplift of the southwest vortex triggered rainfall,and the release of condensation latent heat from rainfall further strengthened the development of the southwest vortex.The significant increase(decrease)in atmospheric diabatic heating and kinetic energy exhibited a delayed progression compared to the increase(decrease)in vorticity.(2)The heating effect around the southwest vortex region was non-uniform,and the heating intensity varied in different stages.In the“8·11”process,the heating effect was the strongest in the initial stage,but weakened during the vortex's development.On the contrary,the heating effect was initially weak in the“8·16”process,and intensified during the development stage.(3)The available potential energy of the“8·11”process significantly increased in kinetic energy converted from rotational and divergent winds through baroclinic action,and the divergent wind energy continued to convert into rotational wind energy.By contrast,the“8·16”process involved the conversion of rotational wind energy into divergent wind energy,which in turn converted kinetic energy back into available potential energy,thereby impeding the further development and maintenance of the southwest vortex.展开更多
The JUNO experiment[1] is the successor to Daya Bay. It envisages the construction of the world’s largest scintillator detector, which it will use primarily to detect reactor neutrinos, with the goal of determining t...The JUNO experiment[1] is the successor to Daya Bay. It envisages the construction of the world’s largest scintillator detector, which it will use primarily to detect reactor neutrinos, with the goal of determining the neutrino mass hierarchy.The cosmogenic muons, i.e. the muons created by the interaction of cosmic rays in the atmosphere, provide a potentially dangerous background. They can interact with the 12C inside the detector creating, among other things, the isotopes 9Li and 8He; some of their decays can emit a neutron, mimicking the double coincidence used to identify the IBD reactor neutrino signal.展开更多
The generation fertility of 51 F1, 19 F2 and 6 BC1 between 3 thermo-sensitive genic male sterile lines (TGMS-lines) Pei'ai 64S, 6311S and 360S, and the three lines of hybrid rice including 7 indica cytoplasmic male...The generation fertility of 51 F1, 19 F2 and 6 BC1 between 3 thermo-sensitive genic male sterile lines (TGMS-lines) Pei'ai 64S, 6311S and 360S, and the three lines of hybrid rice including 7 indica cytoplasmic male sterile lines (CMS-lines) and their corresponding maintainer lines (B-lines) and 3 indica restorer lines (R-lines) were investigated to study the expression of TGMS-genes in the backgrounds of the three lines of hybrid rice. Pei'ai 64S has stronger fertility restoring (Rf) genes for CMS-lines and its TGMS trait is governed by 2 pairs of independent recessive genes; The TGMS trait of 6311S is governed by a single recessive gene with weaker Rf-gene in 6311S and the TGMS trait of 360S is governed by a single recessive gene with no Rf-gene in 360S. The investigation on the fertility of F1 plants between 5 CMS-lines and 4 TGMS generations selected from F2 plants of 4 CMS-lines x 6311S confirmed that the expression of TGMS-gene was controlled by Rf-gene in the genetic background of cytoplasm of CMS-lines, but not affected by Rf-gene in the genetic background of normal fertile cytoplasm. The potential breeding strategies of TGMS-lines with cytoplasm of CMS-lines and CMS-lines with the nucleus of TGMS-genes were discussed.展开更多
The cross-correlation between the high-redshift 21 cm background and the Soft X-ray Background (SXB) of the Universe may provide an additional probe of the Epoch of Reionization. Here we use semi-numerical simulatio...The cross-correlation between the high-redshift 21 cm background and the Soft X-ray Background (SXB) of the Universe may provide an additional probe of the Epoch of Reionization. Here we use semi-numerical simulations to create 21 cm and soft X-ray intensity maps and construct their cross power spectra. Our results indicate that the cross power spectra are sensitive to the thermal and ionizing states of the intergalactic medium (IGM). The 21 cm background correlates positively to the SXB on large scales during the early stages of the reionization. However as the reionization develops, these two back- grounds turn out to be anti-correlated with each other when more than - 15% of the IGM is ionized in a warm reionization scenario. The anti-correlated power reaches its maximum when the neutral fraction declines to 0.2-0.5. Hence, the trough in the cross power spectrum might be a useful tool for tracing the growth of HII regions during the middle and late stages of the reionization. We estimate the detectability of the cross power spectrum based on the abilities of the Square Kilometre Array and the Wide Field X-ray Telescope (WFXT), and find that to detect the cross power spectrum, the pixel noise of X-ray images has to be at least 4 orders of magnitude lower than that of the WFXT deep survey.展开更多
The history of the cosmological reionization is still unclear. Two ionizing sources, stars and QSOs, are believed to play important roles during this epoch. Besides the 21 cm signals, the infrared emission from PopⅢ ...The history of the cosmological reionization is still unclear. Two ionizing sources, stars and QSOs, are believed to play important roles during this epoch. Besides the 21 cm signals, the infrared emission from PopⅢ stars and X-ray photons from QSOs can be powerful probes of the reionization. Here we present a cross-correlation study of the 21 cm, infrared and X-ray backgrounds. The advantage of doing such crosscorrelations is that we could highlight the correlated signals and eliminate irrelevant foregrounds. We develop a shell model to describe the 21 cm signals and find that PopIII stars can provide higher 21 cm signals than QSOs. Using the ROSAT data for X-ray and AKARI data for infrared, we predict various cross power spectra analytically and discuss prospects for detecting these cross-correlation signals in future low frequency radio surveys. We find that, although these cross-correlational signals have distinct features, so far, they have been difficult to detect due to the high noise of the soft X-ray and infrared backgrounds given by ROSAT and AKARI.展开更多
We investigate plane-parallel wave metrics from the point of view of their (Poisson-Lie) T-dualizability. For that purpose we reconstruct the metrics as backgrounds of nonlinear sigma models on Lie groups. For constru...We investigate plane-parallel wave metrics from the point of view of their (Poisson-Lie) T-dualizability. For that purpose we reconstruct the metrics as backgrounds of nonlinear sigma models on Lie groups. For construction of dual backgrounds we use Drinfel’d doubles obtained from the isometry groups of the metrics. We find dilaton fields that enable to satisfy the vanishing beta equations for the duals of the homogenous plane-parallel wave metric. Torsion potentials or B-fields, invariant w.r.t. the isometry group of Lobachevski plane waves are obtained by the Drinfel’d double construction. We show that a certain kind of plurality, different from the (atomic) Poisson-Lie T-plurality, may exist in case that metrics admit several isometry subgroups having the dimension of the Riemannian manifold. An example of that are two different backgrounds dual to the homogenous plane-parallel wave metric.展开更多
The ESA and CAS SMILE mission orbit is highly elliptical and will pass through multiple radiation environments.The Soft X-ray Imager(SXI)instrument aboard has a radiation shutter door designed to close when the surrou...The ESA and CAS SMILE mission orbit is highly elliptical and will pass through multiple radiation environments.The Soft X-ray Imager(SXI)instrument aboard has a radiation shutter door designed to close when the surrounding radiation flux is high.The shutter door will close when passing below an altitude threshold to protect against trapped particles in the Earth’s Van Allen Belts.Therefore,two radiation environments can be approximated based on the shutter door position:open and closed.The instrument background for the CCDs(Charge-Coupled Devices)that form the focal plane array of the SXI were evaluated for the two environments.Due to the correlation of the space environment with the solar cycle,the solar minima and maxima,the background was also evaluated at these two extremes.The results demonstrated that the highest instrument background will occur during solar minima due to the main contributing source being Galactic Cosmic Rays(GCRs).It was also found that the open background was highest for solar minima and that the closed background was highest during solar maxima.This is due to the radiation shutter door acting as a scattering centre and the changes in the energy flux distribution of the GCRs between the two solar extremes.展开更多
P-and SV-wave dispersion and attenuation have been extensively investigated in saturated poroelastic media with aligned fractures.However,there are few existing models that incorporate the multiple wave attenuation me...P-and SV-wave dispersion and attenuation have been extensively investigated in saturated poroelastic media with aligned fractures.However,there are few existing models that incorporate the multiple wave attenuation mechanisms from the microscopic scale to the macroscopic scale.Hence,in this work,we developed a unified model to incorporate the wave attenuation mechanisms at different scales,which includes the microscopic squirt flow between the microcracks and pores,the mesoscopic wave-induced fluid flow between fractures and background(FB-WIFF),and the macroscopic Biot's global flow and elastic scattering(ES)from the fractures.Using Tang's modified Biot's theory and the mixed-boundary conditions,we derived the exact frequency-dependent solutions of the scattering problem for a single penny-shaped fracture with oblique incident P-and SV-waves.We then developed theoretical models for a set of aligned fractures and randomly oriented fractures using the Foldy approximation.The results indicated that microcrack squirt flow considerably influences the dispersion and attenuation of P-and SV-wave velocities.The coupling effects of microcrack squirt flow with the FB-WIFF and ES of fractures cause much higher velocity dispersion and attenuation for P waves than for SV waves.Randomly oriented fractures substantially reduce the attenuation caused by the FB-WIFF and ES,particularly for the ES attenuation of SV waves.Through a comparison with existing models in the limiting cases and previous experimental measurements,we validated our model.展开更多
Based on the lightning observation data from the Fengyun-4A(FY-4A)Lightning Mapping Imager(FY-4A/LMI)and the Lightning Imaging Sensor(LIS)on the International Space Station(ISS),we extract the“event”type data as the...Based on the lightning observation data from the Fengyun-4A(FY-4A)Lightning Mapping Imager(FY-4A/LMI)and the Lightning Imaging Sensor(LIS)on the International Space Station(ISS),we extract the“event”type data as the lightning detection results.These observations are then compared with the cloud-to-ground(CG)lightning observation data from the China Meteorological Administration.This study focuses on the characteristics of lightning activity in Southeast China,primarily in Jiangxi Province and its adjacent areas,from April to September,2017–2022.In addition,with the fifth-generation European Centre for Medium-Range Weather Forecasts reanalysis data,we further delved into the potential factors influencing the distribution and variations in lightning activity and their primary related factors.Our findings indicate that the lightning frequency and density of the FY-4A/LMI,ISS-LIS and CG data are higher in southern and central Jiangxi,central Fujian Province,and western and central Guangdong Province,while they tend to be lower in eastern Hunan Province.In general,the high-value areas of lightning density for the FY-4A/LMI are located in inland mountainous areas.The lower the latitude is,the higher the CG lightning density is.High-value areas of the CG lightning density are more likely to be located in eastern Fujian and southeastern Zhejiang Province.However,the high-value areas of lightning density for the ISS-LIS are more dispersed,with a scattered distribution in inland mountainous areas and along the coast of eastern Fujian.Thus,the mountainous terrain is closely related to the high-value areas of the lightning density.The locations of the high-value areas of the lightning density for the FY-4A/LMI correspond well with those for the CG observations,and the seasonal variations are also consistent.In contrast,the distribution of the high-value areas of the lightning density for the ISS-LIS is more dispersed.The positions of the peak frequency of the FY-4A/LMI lightning and CG lightning contrast with local altitudes,primarily located at lower altitudes or near mountainsides.K-index and convective available potential energy(CAPE)can better reflect the local boundary layer conditions,where the lightning density is higher and lightning seasonal variations are apparent.There are strong correlations in the annual variations between the dew-point temperature(Td)and CG lightning frequency,and the monthly variations of the dew-point temperature and CAPE are also strongly correlated with monthly variations of CG lightning,while they are weakly correlated with the lightning frequency for the FY-4A/LMI and ISS-LIS.This result reflects that the CAPE shows a remarkable effect on the CG lightning frequency during seasonal transitions.展开更多
This study investigated the growth of forecast errors stemming from initial conditions(ICs),lateral boundary conditions(LBCs),and model(MO)perturbations,as well as their interactions,by conducting seven 36 h convectio...This study investigated the growth of forecast errors stemming from initial conditions(ICs),lateral boundary conditions(LBCs),and model(MO)perturbations,as well as their interactions,by conducting seven 36 h convectionallowing ensemble forecast(CAEF)experiments.Two cases,one with strong-forcing(SF)and the other with weak-forcing(WF),occurred over the Yangtze-Huai River basin(YHRB)in East China,were selected to examine the sources of uncertainties associated with perturbation growth under varying forcing backgrounds and the influence of these backgrounds on growth.The perturbations exhibited distinct characteristics in terms of temporal evolution,spatial propagation,and vertical distribution under different forcing backgrounds,indicating a dependence between perturbation growth and forcing background.A comparison of the perturbation growth in different precipitation areas revealed that IC and LBC perturbations were significantly influenced by the location of precipitation in the SF case,while MO perturbations were more responsive to convection triggering and dominated in the WF case.The vertical distribution of perturbations showed that the sources of uncertainties and the performance of perturbations varied between SF and WF cases,with LBC perturbations displaying notable case dependence.Furthermore,the interactions between perturbations were considered by exploring the added values of different source perturbations.For the SF case,the added values of IC,LBC,and MO perturbations were reflected in different forecast periods and different source uncertainties,suggesting that the combination of multi-source perturbations can yield positive interactions.In the WF case,MO perturbations provided a more accurate estimation of uncertainties downstream of the Dabie Mountain and need to be prioritized in the research on perturbation development.展开更多
The close relationship between the English words and culture is analyzed in this article.Only by understanding the hidden cultural meanings in the English words,can college students truly have a good command of them a...The close relationship between the English words and culture is analyzed in this article.Only by understanding the hidden cultural meanings in the English words,can college students truly have a good command of them and can their communicative ability be improved.展开更多
The recently observed gravitational wave background is explained in terms of the quantum modification of the general relativity (Qmoger). Some UFO, FRB and supernova flares also can be explained in terms of Qmoger.
This paper shows how the Flat Space Cosmology model correlates the recom-bination epoch CMB temperature of 3000 K with a cosmological redshift of 1100. This proof is given in support of the recent publication that the...This paper shows how the Flat Space Cosmology model correlates the recom-bination epoch CMB temperature of 3000 K with a cosmological redshift of 1100. This proof is given in support of the recent publication that the Tatum and Seshavatharam Hubble temperature formulae can be derived using the Stephan-Boltzmann dispersion law. Thus, as explained herein, the era of high precision Planck scale quantum cosmology has arrived.展开更多
The purpose of this paper is to introduce new theoretical concepts as opposed to accepting the existence of dark entities, such as dark energy. This research sought to introduce a 2<sup>nd</sup> universal ...The purpose of this paper is to introduce new theoretical concepts as opposed to accepting the existence of dark entities, such as dark energy. This research sought to introduce a 2<sup>nd</sup> universal space-time constant, besides having a finite speed constant (speed of light in vacuum c). A finite universal age constant b is introduced. Namely, this paper shows that the changes in the Earth’s anomalistic year duration over time support the hypothesis of the age of the universe correlating with a maximum number of orbital revolutions constant. Neglecting the gravitational influence of other cosmological entities in the proximity of the Earth, the constant maximum number of revolutions is herewith determined solely by the Earth’s orbital revolutions around the Sun. The value of the universal age constant b is calculated to be around 13.8 billion orbital revolutions, derived out of an equation related to the changes in the Earth’s anomalistic year duration over time and the so-called Hubble tension. The above-mentioned calculated value b correlates well with the best fit to measured data of the cosmic microwave background radiation (CMBR) by the Planck spacecraft, the age of the observed universe is measured to be approximately 13.787 ± 0.020 billion years (2018 final data release). Developing a theory with this 2<sup>nd</sup> universal space-time constant b, being covariant with respect to the Lorentz transformations when time spans are large, gives results such as: A confirmation of the measured CMBR value of 13.787 ± 0.020 billion years. Correlating well with the observed expansion rate of the universe (dark energy). The universe’s expansion accelerating over the last four to five billion years.展开更多
The emergence of new engineering disciplines has resulted in the growing trend of cross-discipline,and the enhancement of students’technical application ability has become the main teaching objective of engineering d...The emergence of new engineering disciplines has resulted in the growing trend of cross-discipline,and the enhancement of students’technical application ability has become the main teaching objective of engineering disciplines.For this reason,the Internet of Things(IoT)engineering program should be actively reformed,providing students with sufficient opportunities to improve their practical skills.This paper identifies the challenges within practical teaching of IoT engineering,delves into effective strategies for practical IoT teaching within the context of emerging engineering disciplines,and presents practical teaching experiences from the School of Information Engineering at Hainan University of Science and Technology as a case study.The aim is to offer guidance and insights to educators in this field.展开更多
The theory of Relation provides an explanation for the Arcade 2 excess. It assumes that the isotropic radio emission measured by the Arcade 2 Collaboration, which is 5 - 6 times brighter than the expected contribution...The theory of Relation provides an explanation for the Arcade 2 excess. It assumes that the isotropic radio emission measured by the Arcade 2 Collaboration, which is 5 - 6 times brighter than the expected contributions from known extra-galactic sources, is the residue of an immense primitive energy of ordinary matter released by a relativistic bang almost 100 million years after the big bang, which gave the mass-energy the missing gravity to activate contraction. This relativistic bang, via a Lorentz energy transformation, would have released enormous energy held to be the source of the powerful radio noise detected by the NASA researchers. This transformation would have simultaneously triggered the formation of the first stars from dense gas and the reionization of less dense neutral gas. This departs from the idea that continuous reionization began after the formation of the first stars. We emphasize the importance of primordial magnetic fields, which would have generated significant density fluctuations during recombination and acted as a direct seed for cosmic structures. The first stars and galaxies were bathed in strong magnetic fields that gave rise to the radio microwave din (boom) discovered by Arcade 2. These intense magnetic fields alter the trajectory of charged particles zooming near the speed of light, triggering the space roar and emitting radiation that forms a synchrotron radio background. The theory of Relation offers an alternative to the Lambda-CDM cosmological model, which has become the standard model of the big bang, which leads straight to the vacuum catastrophe.展开更多
Previously, we presented several empirical equations using the cosmic microwave background (CMB) temperature. Next, we propose an empirical equation for the fine-structure constant. Considering the compatibility among...Previously, we presented several empirical equations using the cosmic microwave background (CMB) temperature. Next, we propose an empirical equation for the fine-structure constant. Considering the compatibility among these empirical equations, the CMB temperature (T<sub>c</sub>) and gravitational constant (G) were calculated to be 2.726312 K and 6.673778 × 10<sup>−11</sup> m<sup>3</sup>∙kg<sup>−1</sup>∙s<sup>−2</sup>, respectively. Every equation could be explained in terms of the Compton length of an electron (λ<sub>e</sub>), the Compton length of a proton (λ<sub>p</sub>) and a. Furthermore, every equation could also be explained in terms of Avogadro’s number and the number of electrons in 1 C. However, the ratio of the gravitational force to the electric force cannot be uniquely determined when the unit of the Planck constant (Js) is changed. In this study, we showed that every equation can be described in terms of Planck constant. From the assumption of minimum mass, the ratio of gravitational force to electric force could be elucidated.展开更多
Previously, we presented several empirical equations using the cosmic microwave background (CMB) temperature that were mathematically connected. Next, we proposed an empirical equation for the fine-structure constant....Previously, we presented several empirical equations using the cosmic microwave background (CMB) temperature that were mathematically connected. Next, we proposed an empirical equation for the fine-structure constant. Considering the compatibility among these empirical equations, the CMB temperature (T<sub>c</sub>) and gravitational constant (G) were calculated to be 2.726312 K and 6.673778 × 10<sup>-11</sup> m<sup>3</sup>·kg<sup>-1</sup>·s<sup>-2</sup>, respectively. Every equation can be explained in terms of the Compton length of an electron (λ<sub>e</sub>), the Compton length of a proton (λ<sub>p</sub>) and α. However, these equations are difficult to follow. Using the correspondence principle with the thermodynamic principles in solid-state ionics, we propose a canonical ensemble to explain these equations in this report. For this purpose, we show that every equation can be explained in terms of Avogadro’s number and the number of electrons in 1 C.展开更多
The Neoproterozoic-Cambrian(N-C) and Permian-Triassic(P-T) transitions have been regarded the two most critical transitions in earth history because of the explosive biological radiation in the early Cambrian(the Camb...The Neoproterozoic-Cambrian(N-C) and Permian-Triassic(P-T) transitions have been regarded the two most critical transitions in earth history because of the explosive biological radiation in the early Cambrian(the Cambrian Explosion) and the largest mass extinction at the end-Permian.Previous studies suggest that these two critical transitions showed certain comparability in major evolutionary events.In other words,a series of biological,geological,and geochemical events that had happened in the N-C transition occurred repeatedly during the P-T transition.Those events included continental re-configuration related to the deep mantle dynamics,global-scale glaciations,large C-,Sr-,and S-isotope perturbations indicating atmospheric and oceanic changes,abnormal precipitation of carbonates,and associated multiple biological radiations and mass extinctions.The coupling of those events in both N-C and P-T transitions suggests that deep mantle dynamics could be a primary mechanism driving dramatic changes of environment on the earth's surface,which in turn caused major biological re-organizations.A detailed comparison of those events during the two critical transitions indicates that despite their general comparability,significant differences do exist in magnitude,duration,and frequency.The supercontinent Rodinia began to rift before the Snowball Earth time.By contrast,the supercontinent Pangea entered the dispersal stage after the greatest glaciation from the Late Carboniferous to Cisuralian.Quantitative data and qualitative analyses of different fossil groups show a more profound mass extinction during the N-C transition than at the end-Permian in terms of ecosystem disruption.This is indicated by the disappearance of the whole Ediacaran biota at the N-C boundary.The subsequent appearances of many new complex animals at phylum level in the early Cambrian mark the establishment of a brand new ecosystem.However,the end-Permian mass extinction is manifested mainly by the extinction of many different taxa at class and order levels.Although it caused the extinction of 95% of marine species and 75% of terrestrial species as well as complete cessation of coal and reef deposits after the mass extinction,this high-level biological re-organization still occurred within an established ecosystem,however drastic it may seem.Survived or Lazarus taxa re-occupied the existing ecospace in a relatively short duration after the end-Permian mass extinction.C-isotope excursions display large perturbations during both transitions,yet also in different magnitudes and frequencies,which suggest different atmospheric and oceanic conditions.The recurrent geological and geochemical events as well as the coupled major biological turnovers during the two transitions provide new clues to understanding the interplays among the earth-life system.Thus,it is essential to carry out multidisciplinary studies from the deep internal system to the surface of the Earth as a whole in order to unravel the interactions of different spheres of the earth.展开更多
We present one family of general analytical solutions for the generalized nonlinear Schr?dinger equation with time-space modulation via the method of a combination of the Darboux transformation and similarity transfor...We present one family of general analytical solutions for the generalized nonlinear Schr?dinger equation with time-space modulation via the method of a combination of the Darboux transformation and similarity transformation. Nonlinear waves on different localized and periodic backgrounds depending on the corresponding nonlinearity modulations are obtained. In particular, we demonstrate the existence and property of localized modes on a doubleperiodic background under a special designed optical lattice potential. Our results may raise the possibility of related experiments and potential applications in nonlinear optics and Bose–Einstein condensates.展开更多
基金Key Project of Joint Meteorological Fund of the National Natural Science Foundation of China (U2242202)Key Project of the National Natural Science Foundation of China (42030611)+1 种基金Innovative Development Special Project of China Meteorological Administration (CXFZ2023J016)Innovation Team Fund of Sichuan Provincial Meteorological Service (SCQXCX7D-202201)。
文摘Based on ERA5 reanalysis data,the present study analyzed the thermal energy development mechanism and kinetic energy conversion characteristics of two extreme rainstorm processes in relation to the shallow southwest vortex in the warm-sector during a“rain-generated vortex”process and the deep southwest vortex in a“vortex-generated rain”process.The findings were as follows:(1)During the extreme rainstorm on August 11,2020(hereinafter referred to as the“8·11”process),intense surface heating and a high-energy unstable environment were observed.The mesoscale convergence system triggered convection to produce heavy rainfall,and the release of latent condensation heat generated by the rainfall promoted the formation of a southwest vortex.The significant increase(decrease)in atmospheric diabatic heating and kinetic energy preceded the increase(decrease)in vorticity.By contrast,the extreme rainstorm on August 16,2020(hereinafter referred to as the“8·16”process)involved the generation of southwest vortex in a low-energy and highhumidity environment.The dynamic uplift of the southwest vortex triggered rainfall,and the release of condensation latent heat from rainfall further strengthened the development of the southwest vortex.The significant increase(decrease)in atmospheric diabatic heating and kinetic energy exhibited a delayed progression compared to the increase(decrease)in vorticity.(2)The heating effect around the southwest vortex region was non-uniform,and the heating intensity varied in different stages.In the“8·11”process,the heating effect was the strongest in the initial stage,but weakened during the vortex's development.On the contrary,the heating effect was initially weak in the“8·16”process,and intensified during the development stage.(3)The available potential energy of the“8·11”process significantly increased in kinetic energy converted from rotational and divergent winds through baroclinic action,and the divergent wind energy continued to convert into rotational wind energy.By contrast,the“8·16”process involved the conversion of rotational wind energy into divergent wind energy,which in turn converted kinetic energy back into available potential energy,thereby impeding the further development and maintenance of the southwest vortex.
文摘The JUNO experiment[1] is the successor to Daya Bay. It envisages the construction of the world’s largest scintillator detector, which it will use primarily to detect reactor neutrinos, with the goal of determining the neutrino mass hierarchy.The cosmogenic muons, i.e. the muons created by the interaction of cosmic rays in the atmosphere, provide a potentially dangerous background. They can interact with the 12C inside the detector creating, among other things, the isotopes 9Li and 8He; some of their decays can emit a neutron, mimicking the double coincidence used to identify the IBD reactor neutrino signal.
文摘The generation fertility of 51 F1, 19 F2 and 6 BC1 between 3 thermo-sensitive genic male sterile lines (TGMS-lines) Pei'ai 64S, 6311S and 360S, and the three lines of hybrid rice including 7 indica cytoplasmic male sterile lines (CMS-lines) and their corresponding maintainer lines (B-lines) and 3 indica restorer lines (R-lines) were investigated to study the expression of TGMS-genes in the backgrounds of the three lines of hybrid rice. Pei'ai 64S has stronger fertility restoring (Rf) genes for CMS-lines and its TGMS trait is governed by 2 pairs of independent recessive genes; The TGMS trait of 6311S is governed by a single recessive gene with weaker Rf-gene in 6311S and the TGMS trait of 360S is governed by a single recessive gene with no Rf-gene in 360S. The investigation on the fertility of F1 plants between 5 CMS-lines and 4 TGMS generations selected from F2 plants of 4 CMS-lines x 6311S confirmed that the expression of TGMS-gene was controlled by Rf-gene in the genetic background of cytoplasm of CMS-lines, but not affected by Rf-gene in the genetic background of normal fertile cytoplasm. The potential breeding strategies of TGMS-lines with cytoplasm of CMS-lines and CMS-lines with the nucleus of TGMS-genes were discussed.
基金supported by the National Natural Science Foundation of China(Grant Nos.11473031,11261140641 and 11173028)the 973 Program(Grant No.2013CB837900)
文摘The cross-correlation between the high-redshift 21 cm background and the Soft X-ray Background (SXB) of the Universe may provide an additional probe of the Epoch of Reionization. Here we use semi-numerical simulations to create 21 cm and soft X-ray intensity maps and construct their cross power spectra. Our results indicate that the cross power spectra are sensitive to the thermal and ionizing states of the intergalactic medium (IGM). The 21 cm background correlates positively to the SXB on large scales during the early stages of the reionization. However as the reionization develops, these two back- grounds turn out to be anti-correlated with each other when more than - 15% of the IGM is ionized in a warm reionization scenario. The anti-correlated power reaches its maximum when the neutral fraction declines to 0.2-0.5. Hence, the trough in the cross power spectrum might be a useful tool for tracing the growth of HII regions during the middle and late stages of the reionization. We estimate the detectability of the cross power spectrum based on the abilities of the Square Kilometre Array and the Wide Field X-ray Telescope (WFXT), and find that to detect the cross power spectrum, the pixel noise of X-ray images has to be at least 4 orders of magnitude lower than that of the WFXT deep survey.
基金supported by a CAS grant KJCX3-SYW-N2.References
文摘The history of the cosmological reionization is still unclear. Two ionizing sources, stars and QSOs, are believed to play important roles during this epoch. Besides the 21 cm signals, the infrared emission from PopⅢ stars and X-ray photons from QSOs can be powerful probes of the reionization. Here we present a cross-correlation study of the 21 cm, infrared and X-ray backgrounds. The advantage of doing such crosscorrelations is that we could highlight the correlated signals and eliminate irrelevant foregrounds. We develop a shell model to describe the 21 cm signals and find that PopIII stars can provide higher 21 cm signals than QSOs. Using the ROSAT data for X-ray and AKARI data for infrared, we predict various cross power spectra analytically and discuss prospects for detecting these cross-correlation signals in future low frequency radio surveys. We find that, although these cross-correlational signals have distinct features, so far, they have been difficult to detect due to the high noise of the soft X-ray and infrared backgrounds given by ROSAT and AKARI.
基金supported by the research plan LC527 of the Ministry of Education of the Czech Republic.
文摘We investigate plane-parallel wave metrics from the point of view of their (Poisson-Lie) T-dualizability. For that purpose we reconstruct the metrics as backgrounds of nonlinear sigma models on Lie groups. For construction of dual backgrounds we use Drinfel’d doubles obtained from the isometry groups of the metrics. We find dilaton fields that enable to satisfy the vanishing beta equations for the duals of the homogenous plane-parallel wave metric. Torsion potentials or B-fields, invariant w.r.t. the isometry group of Lobachevski plane waves are obtained by the Drinfel’d double construction. We show that a certain kind of plurality, different from the (atomic) Poisson-Lie T-plurality, may exist in case that metrics admit several isometry subgroups having the dimension of the Riemannian manifold. An example of that are two different backgrounds dual to the homogenous plane-parallel wave metric.
文摘The ESA and CAS SMILE mission orbit is highly elliptical and will pass through multiple radiation environments.The Soft X-ray Imager(SXI)instrument aboard has a radiation shutter door designed to close when the surrounding radiation flux is high.The shutter door will close when passing below an altitude threshold to protect against trapped particles in the Earth’s Van Allen Belts.Therefore,two radiation environments can be approximated based on the shutter door position:open and closed.The instrument background for the CCDs(Charge-Coupled Devices)that form the focal plane array of the SXI were evaluated for the two environments.Due to the correlation of the space environment with the solar cycle,the solar minima and maxima,the background was also evaluated at these two extremes.The results demonstrated that the highest instrument background will occur during solar minima due to the main contributing source being Galactic Cosmic Rays(GCRs).It was also found that the open background was highest for solar minima and that the closed background was highest during solar maxima.This is due to the radiation shutter door acting as a scattering centre and the changes in the energy flux distribution of the GCRs between the two solar extremes.
基金This work was supported by the Laoshan National Laboratory Science and Technology Innovation Project(No.LSKJ202203407)the National Natural Science Foundation of China(Grant Nos.42174145,41821002,42274146)+1 种基金Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology(2022B1212010002)Shenzhen Stable Support Plan Program for Higher Education Institutions(20220815110144003).
文摘P-and SV-wave dispersion and attenuation have been extensively investigated in saturated poroelastic media with aligned fractures.However,there are few existing models that incorporate the multiple wave attenuation mechanisms from the microscopic scale to the macroscopic scale.Hence,in this work,we developed a unified model to incorporate the wave attenuation mechanisms at different scales,which includes the microscopic squirt flow between the microcracks and pores,the mesoscopic wave-induced fluid flow between fractures and background(FB-WIFF),and the macroscopic Biot's global flow and elastic scattering(ES)from the fractures.Using Tang's modified Biot's theory and the mixed-boundary conditions,we derived the exact frequency-dependent solutions of the scattering problem for a single penny-shaped fracture with oblique incident P-and SV-waves.We then developed theoretical models for a set of aligned fractures and randomly oriented fractures using the Foldy approximation.The results indicated that microcrack squirt flow considerably influences the dispersion and attenuation of P-and SV-wave velocities.The coupling effects of microcrack squirt flow with the FB-WIFF and ES of fractures cause much higher velocity dispersion and attenuation for P waves than for SV waves.Randomly oriented fractures substantially reduce the attenuation caused by the FB-WIFF and ES,particularly for the ES attenuation of SV waves.Through a comparison with existing models in the limiting cases and previous experimental measurements,we validated our model.
基金National Natural Science Foundation of China(42175014,42205137)Open Research Fund of Institute of Meteorological Technology Innovation,Nanjing(BJG202202)+3 种基金Joint Research Project of Typhoon Research,Shanghai Typhoon Institute,China Meteorological Administration(TFJJ202209)Innovation Development Project of China Meteorological Administration(CXFZ2023P001)Open Project of KLME&CIC-FEMD(KLME202311)Jiangxi MDIA-ASI Fund。
文摘Based on the lightning observation data from the Fengyun-4A(FY-4A)Lightning Mapping Imager(FY-4A/LMI)and the Lightning Imaging Sensor(LIS)on the International Space Station(ISS),we extract the“event”type data as the lightning detection results.These observations are then compared with the cloud-to-ground(CG)lightning observation data from the China Meteorological Administration.This study focuses on the characteristics of lightning activity in Southeast China,primarily in Jiangxi Province and its adjacent areas,from April to September,2017–2022.In addition,with the fifth-generation European Centre for Medium-Range Weather Forecasts reanalysis data,we further delved into the potential factors influencing the distribution and variations in lightning activity and their primary related factors.Our findings indicate that the lightning frequency and density of the FY-4A/LMI,ISS-LIS and CG data are higher in southern and central Jiangxi,central Fujian Province,and western and central Guangdong Province,while they tend to be lower in eastern Hunan Province.In general,the high-value areas of lightning density for the FY-4A/LMI are located in inland mountainous areas.The lower the latitude is,the higher the CG lightning density is.High-value areas of the CG lightning density are more likely to be located in eastern Fujian and southeastern Zhejiang Province.However,the high-value areas of lightning density for the ISS-LIS are more dispersed,with a scattered distribution in inland mountainous areas and along the coast of eastern Fujian.Thus,the mountainous terrain is closely related to the high-value areas of the lightning density.The locations of the high-value areas of the lightning density for the FY-4A/LMI correspond well with those for the CG observations,and the seasonal variations are also consistent.In contrast,the distribution of the high-value areas of the lightning density for the ISS-LIS is more dispersed.The positions of the peak frequency of the FY-4A/LMI lightning and CG lightning contrast with local altitudes,primarily located at lower altitudes or near mountainsides.K-index and convective available potential energy(CAPE)can better reflect the local boundary layer conditions,where the lightning density is higher and lightning seasonal variations are apparent.There are strong correlations in the annual variations between the dew-point temperature(Td)and CG lightning frequency,and the monthly variations of the dew-point temperature and CAPE are also strongly correlated with monthly variations of CG lightning,while they are weakly correlated with the lightning frequency for the FY-4A/LMI and ISS-LIS.This result reflects that the CAPE shows a remarkable effect on the CG lightning frequency during seasonal transitions.
基金Key Project of the National Natural Science Foundation of China (42330611)National Natural Science Foundation of China (42105008)。
文摘This study investigated the growth of forecast errors stemming from initial conditions(ICs),lateral boundary conditions(LBCs),and model(MO)perturbations,as well as their interactions,by conducting seven 36 h convectionallowing ensemble forecast(CAEF)experiments.Two cases,one with strong-forcing(SF)and the other with weak-forcing(WF),occurred over the Yangtze-Huai River basin(YHRB)in East China,were selected to examine the sources of uncertainties associated with perturbation growth under varying forcing backgrounds and the influence of these backgrounds on growth.The perturbations exhibited distinct characteristics in terms of temporal evolution,spatial propagation,and vertical distribution under different forcing backgrounds,indicating a dependence between perturbation growth and forcing background.A comparison of the perturbation growth in different precipitation areas revealed that IC and LBC perturbations were significantly influenced by the location of precipitation in the SF case,while MO perturbations were more responsive to convection triggering and dominated in the WF case.The vertical distribution of perturbations showed that the sources of uncertainties and the performance of perturbations varied between SF and WF cases,with LBC perturbations displaying notable case dependence.Furthermore,the interactions between perturbations were considered by exploring the added values of different source perturbations.For the SF case,the added values of IC,LBC,and MO perturbations were reflected in different forecast periods and different source uncertainties,suggesting that the combination of multi-source perturbations can yield positive interactions.In the WF case,MO perturbations provided a more accurate estimation of uncertainties downstream of the Dabie Mountain and need to be prioritized in the research on perturbation development.
文摘The close relationship between the English words and culture is analyzed in this article.Only by understanding the hidden cultural meanings in the English words,can college students truly have a good command of them and can their communicative ability be improved.
文摘The recently observed gravitational wave background is explained in terms of the quantum modification of the general relativity (Qmoger). Some UFO, FRB and supernova flares also can be explained in terms of Qmoger.
文摘This paper shows how the Flat Space Cosmology model correlates the recom-bination epoch CMB temperature of 3000 K with a cosmological redshift of 1100. This proof is given in support of the recent publication that the Tatum and Seshavatharam Hubble temperature formulae can be derived using the Stephan-Boltzmann dispersion law. Thus, as explained herein, the era of high precision Planck scale quantum cosmology has arrived.
文摘The purpose of this paper is to introduce new theoretical concepts as opposed to accepting the existence of dark entities, such as dark energy. This research sought to introduce a 2<sup>nd</sup> universal space-time constant, besides having a finite speed constant (speed of light in vacuum c). A finite universal age constant b is introduced. Namely, this paper shows that the changes in the Earth’s anomalistic year duration over time support the hypothesis of the age of the universe correlating with a maximum number of orbital revolutions constant. Neglecting the gravitational influence of other cosmological entities in the proximity of the Earth, the constant maximum number of revolutions is herewith determined solely by the Earth’s orbital revolutions around the Sun. The value of the universal age constant b is calculated to be around 13.8 billion orbital revolutions, derived out of an equation related to the changes in the Earth’s anomalistic year duration over time and the so-called Hubble tension. The above-mentioned calculated value b correlates well with the best fit to measured data of the cosmic microwave background radiation (CMBR) by the Planck spacecraft, the age of the observed universe is measured to be approximately 13.787 ± 0.020 billion years (2018 final data release). Developing a theory with this 2<sup>nd</sup> universal space-time constant b, being covariant with respect to the Lorentz transformations when time spans are large, gives results such as: A confirmation of the measured CMBR value of 13.787 ± 0.020 billion years. Correlating well with the observed expansion rate of the universe (dark energy). The universe’s expansion accelerating over the last four to five billion years.
文摘The emergence of new engineering disciplines has resulted in the growing trend of cross-discipline,and the enhancement of students’technical application ability has become the main teaching objective of engineering disciplines.For this reason,the Internet of Things(IoT)engineering program should be actively reformed,providing students with sufficient opportunities to improve their practical skills.This paper identifies the challenges within practical teaching of IoT engineering,delves into effective strategies for practical IoT teaching within the context of emerging engineering disciplines,and presents practical teaching experiences from the School of Information Engineering at Hainan University of Science and Technology as a case study.The aim is to offer guidance and insights to educators in this field.
文摘The theory of Relation provides an explanation for the Arcade 2 excess. It assumes that the isotropic radio emission measured by the Arcade 2 Collaboration, which is 5 - 6 times brighter than the expected contributions from known extra-galactic sources, is the residue of an immense primitive energy of ordinary matter released by a relativistic bang almost 100 million years after the big bang, which gave the mass-energy the missing gravity to activate contraction. This relativistic bang, via a Lorentz energy transformation, would have released enormous energy held to be the source of the powerful radio noise detected by the NASA researchers. This transformation would have simultaneously triggered the formation of the first stars from dense gas and the reionization of less dense neutral gas. This departs from the idea that continuous reionization began after the formation of the first stars. We emphasize the importance of primordial magnetic fields, which would have generated significant density fluctuations during recombination and acted as a direct seed for cosmic structures. The first stars and galaxies were bathed in strong magnetic fields that gave rise to the radio microwave din (boom) discovered by Arcade 2. These intense magnetic fields alter the trajectory of charged particles zooming near the speed of light, triggering the space roar and emitting radiation that forms a synchrotron radio background. The theory of Relation offers an alternative to the Lambda-CDM cosmological model, which has become the standard model of the big bang, which leads straight to the vacuum catastrophe.
文摘Previously, we presented several empirical equations using the cosmic microwave background (CMB) temperature. Next, we propose an empirical equation for the fine-structure constant. Considering the compatibility among these empirical equations, the CMB temperature (T<sub>c</sub>) and gravitational constant (G) were calculated to be 2.726312 K and 6.673778 × 10<sup>−11</sup> m<sup>3</sup>∙kg<sup>−1</sup>∙s<sup>−2</sup>, respectively. Every equation could be explained in terms of the Compton length of an electron (λ<sub>e</sub>), the Compton length of a proton (λ<sub>p</sub>) and a. Furthermore, every equation could also be explained in terms of Avogadro’s number and the number of electrons in 1 C. However, the ratio of the gravitational force to the electric force cannot be uniquely determined when the unit of the Planck constant (Js) is changed. In this study, we showed that every equation can be described in terms of Planck constant. From the assumption of minimum mass, the ratio of gravitational force to electric force could be elucidated.
文摘Previously, we presented several empirical equations using the cosmic microwave background (CMB) temperature that were mathematically connected. Next, we proposed an empirical equation for the fine-structure constant. Considering the compatibility among these empirical equations, the CMB temperature (T<sub>c</sub>) and gravitational constant (G) were calculated to be 2.726312 K and 6.673778 × 10<sup>-11</sup> m<sup>3</sup>·kg<sup>-1</sup>·s<sup>-2</sup>, respectively. Every equation can be explained in terms of the Compton length of an electron (λ<sub>e</sub>), the Compton length of a proton (λ<sub>p</sub>) and α. However, these equations are difficult to follow. Using the correspondence principle with the thermodynamic principles in solid-state ionics, we propose a canonical ensemble to explain these equations in this report. For this purpose, we show that every equation can be explained in terms of Avogadro’s number and the number of electrons in 1 C.
基金supported by National Basic Research Program of China (Grant Nos. 2006CB860400, 2011CB808905)Chinese Academy of Sciences (Grant No. KZCX2-YW-Q08-4)NSFC and the CAS/SAFEA International Partnership Program for Creative Research Teams
文摘The Neoproterozoic-Cambrian(N-C) and Permian-Triassic(P-T) transitions have been regarded the two most critical transitions in earth history because of the explosive biological radiation in the early Cambrian(the Cambrian Explosion) and the largest mass extinction at the end-Permian.Previous studies suggest that these two critical transitions showed certain comparability in major evolutionary events.In other words,a series of biological,geological,and geochemical events that had happened in the N-C transition occurred repeatedly during the P-T transition.Those events included continental re-configuration related to the deep mantle dynamics,global-scale glaciations,large C-,Sr-,and S-isotope perturbations indicating atmospheric and oceanic changes,abnormal precipitation of carbonates,and associated multiple biological radiations and mass extinctions.The coupling of those events in both N-C and P-T transitions suggests that deep mantle dynamics could be a primary mechanism driving dramatic changes of environment on the earth's surface,which in turn caused major biological re-organizations.A detailed comparison of those events during the two critical transitions indicates that despite their general comparability,significant differences do exist in magnitude,duration,and frequency.The supercontinent Rodinia began to rift before the Snowball Earth time.By contrast,the supercontinent Pangea entered the dispersal stage after the greatest glaciation from the Late Carboniferous to Cisuralian.Quantitative data and qualitative analyses of different fossil groups show a more profound mass extinction during the N-C transition than at the end-Permian in terms of ecosystem disruption.This is indicated by the disappearance of the whole Ediacaran biota at the N-C boundary.The subsequent appearances of many new complex animals at phylum level in the early Cambrian mark the establishment of a brand new ecosystem.However,the end-Permian mass extinction is manifested mainly by the extinction of many different taxa at class and order levels.Although it caused the extinction of 95% of marine species and 75% of terrestrial species as well as complete cessation of coal and reef deposits after the mass extinction,this high-level biological re-organization still occurred within an established ecosystem,however drastic it may seem.Survived or Lazarus taxa re-occupied the existing ecospace in a relatively short duration after the end-Permian mass extinction.C-isotope excursions display large perturbations during both transitions,yet also in different magnitudes and frequencies,which suggest different atmospheric and oceanic conditions.The recurrent geological and geochemical events as well as the coupled major biological turnovers during the two transitions provide new clues to understanding the interplays among the earth-life system.Thus,it is essential to carry out multidisciplinary studies from the deep internal system to the surface of the Earth as a whole in order to unravel the interactions of different spheres of the earth.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11475135 and 11547302
文摘We present one family of general analytical solutions for the generalized nonlinear Schr?dinger equation with time-space modulation via the method of a combination of the Darboux transformation and similarity transformation. Nonlinear waves on different localized and periodic backgrounds depending on the corresponding nonlinearity modulations are obtained. In particular, we demonstrate the existence and property of localized modes on a doubleperiodic background under a special designed optical lattice potential. Our results may raise the possibility of related experiments and potential applications in nonlinear optics and Bose–Einstein condensates.