According to models such as panspermia or the Nebula-Relay hypothesis,the ancestors of life on Earth once lived in molecular clouds.Then what are the energy source and bioenergetics for such lifeforms?A new bioenerget...According to models such as panspermia or the Nebula-Relay hypothesis,the ancestors of life on Earth once lived in molecular clouds.Then what are the energy source and bioenergetics for such lifeforms?A new bioenergetic mechanism powered by cosmic ray ionization of hydrogen molecules is proposed and its relation with the origin of chemiosmosis is also discussed in this paper.Based on this mechanism,the Last Universal Common Ancestor may be a type of lifeform that utilizes hydrogen molecules as donors of electron transport chains.展开更多
Traditional parafoil homing usually uses a point as object. As the mobility of parafoil is limited by its glide ratio and wind, in some cases when the parafoil scatter area is large, or the glide ratio of parafoil is ...Traditional parafoil homing usually uses a point as object. As the mobility of parafoil is limited by its glide ratio and wind, in some cases when the parafoil scatter area is large, or the glide ratio of parafoil is small, the deviation of its landing point to object point will be arduous to control. Accordingly, during these situations, when parafoil is used in recovery of spacecraft or satellite, the landing area of parafoil can be set as a rectangle, and the object of parafoil can be set as a line segment. The thesis of this work is designing an algorithm for parafoil homing using line segment as object. The algorithm of wind velocity and direction calculation in different flying segments was also investigated. The algorithm designed navigates the parafoil to land into the predestined area and largely reduce the probability of recovery loads falling to unwanted area to damage houses and people.展开更多
When Merlin first appears in Chaviano＇s Fables of an Extraterrestrial Grandmother as the wizard Soio, he reflects the imagination of Ana, the adolescent protagonist of the science fiction novel as she is in the proce...When Merlin first appears in Chaviano＇s Fables of an Extraterrestrial Grandmother as the wizard Soio, he reflects the imagination of Ana, the adolescent protagonist of the science fiction novel as she is in the process of writing the very novel the reader is reading. Later she will discover that her fictional creations are not the invention of her imagination but exist autonomously in parallel universes and are using her as a vehicle of inter-dimensional travel through time and space. Soio/Merlin gazes into his crystal ball, a microcosm that gathers the space-time energy fields of the parallel universes, and sees visions of the protagonists whose modes of existence are real in one and fictional in another parallel universe. Merlin is a Druid in exile from the Neolithic world of Celtic Britain who has crossed over from earthly life to existence in Rybel, a parallel universe. He had crossed over by lining up the Stone of the Past and the Mirror of the Future at the great circle of Stonehenge. The stone circle functioned as an astronomical observatory. Stonehenge is a microcosm, a circle that reflects and coordinates the larger circle of the universe, symbolized and embodied in the sphere or crystal ball that Merlin transmits to Ana in the form of the novel being read. All the characters are trying to coordinate dimensions of space and time in order to fly from one parallel universe to another. Chaviano emphasizes crossing boundaries of time and space. Her characters live in one world but belonging to another, yearn to make contact with the forces of the universe that will bring them home. Chaviano＇s use of the Merlin legend is original and takes into account archaeological evidence about the Celts, Druids, and Stonehenge.展开更多
There is an apparent tension between cosmological parameters obtained from Planck cosmic microwave background radiation observations and that derived from the observed magnitude-redshift relation for the type Ia super...There is an apparent tension between cosmological parameters obtained from Planck cosmic microwave background radiation observations and that derived from the observed magnitude-redshift relation for the type Ia supernova （SNe Ia）. Here, we show that the tension can be alleviated, if we first calibrate, with the help of the distance-duality relation, the light-curve fitting parameters in the distance estimation in SNe Ia observations with the angular diameter distance data of the galaxy clusters and then re-estimate the distances for the SNe Ia with the corrected fitting parameters. This was used to explore their cosmological implications in the context of the spatially fiat cosmology. We find a higher value for the matter density parameter, Ωm, as compared to that from the original SNLS3, which is in agreement with Planck observations at 68.3% confidence. Therefore, the tension between Planck measurements and SNe Ia observations regarding Ωm can be effectively alleviated without invoking new physics or resorting to extensions for the standard concordance model. Moreover, with the absolute magnitude of a fiducial SNe Ia, M, determined first, we obtained a constraint on the Hubble constant with SNLS3 alone, which is also consistent with Planck.展开更多
The validity of distance duality relation, η = D L (z)(1 + z) 2 /D A (z) = 1, an exact result required by the Etherington reciprocity theorem, where D A (z) and D L (z) are the angular and luminosity distances, plays...The validity of distance duality relation, η = D L (z)(1 + z) 2 /D A (z) = 1, an exact result required by the Etherington reciprocity theorem, where D A (z) and D L (z) are the angular and luminosity distances, plays an essential part in cosmological observations and model constraints. In this paper, we investigate some consequences of such a relation by assuming η a constant or a function of the redshift. In order to constrain the parameters concerning η, we consider two groups of cluster gas mass fraction data including 52 X-ray luminous galaxy clusters observed by Chandra in the redshift range from 0.3 to 1.273 and temperature range T gas > 4 keV, under the assumptions of two different temperature profiles. We find that the constant temperature profile is in relatively good agreement with no violation of the distance duality relation for both parameterizations of η, while the one with temperature gradient (the Vikhlinin et al. temperature profile) seems to be incompatible even at 99% CL.展开更多
By phenomenologically describing the high-redshift star formation history, i.e., ,ρ.（z） oc [（1 ＋z）/4.5]-% and semi-analytically calculating the fractions of high-redshift Pop I/II and Pop II! stars, we investiga...By phenomenologically describing the high-redshift star formation history, i.e., ,ρ.（z） oc [（1 ＋z）/4.5]-% and semi-analytically calculating the fractions of high-redshift Pop I/II and Pop II! stars, we investigate the contributions from both high-redshfit Pop I/II and Pop II/stars to the observed near-infrared （3 μm 〈// 〈 5 μm） excess in the cosmic infrared background emission. In order to account for the observational level of the near-infrared excess, the power-law index or of the assumed star formation history is constrained to within the range of 0 ≤a≤1. Such a constraint is obtained under the condition that the viral temperature of dark matter halos belongs to the range of 500 K ≤ Tvir≤ 104 K.展开更多
Boron nuclei in cosmic rays(CRs)are believed to be mainly produced by the fragmentation of heavier nuclei,such as carbon and oxygen,via collisions with the interstellar matter.Therefore,the boron-tocarbon flux ratio(B...Boron nuclei in cosmic rays(CRs)are believed to be mainly produced by the fragmentation of heavier nuclei,such as carbon and oxygen,via collisions with the interstellar matter.Therefore,the boron-tocarbon flux ratio(B/C)and the boron-to-oxygen flux ratio(B/O)are very essential probes of the CR propagation.The energy dependence of the B/C ratio from previous balloon-borne and space-based experiments can be well described by a single power-law up to about 1 TeV/n within uncertainties.This work reports direct measurements of B/C and B/O in the energy range from 10 Ge V/n to 5.6 TeV/n with 6 years of data collected by the Dark Matter Particle Explorer,with high statistics and well controlled systematic uncertainties.The energy dependence of both the B/C and B/O ratios can be well fitted by a broken power-law model rather than a single power-law model,suggesting the existence in both flux ratios of a spectral hardening at about 100 Ge V/n.The significance of the break is about 5.6σand 6.9σfor the GEANT4 simulation,and 4.4σand 6.9σfor the alternative FLUKA simulation,for B/C and B/O,respectively.These results deviate from the predictions of conventional turbulence theories of the interstellar medium(ISM),which point toward a change of turbulence properties of the ISM at different scales or novel propagation effects of CRs,and should be properly incorporated in the indirect detection of dark matter via anti-matter particles.展开更多
We investigate a matter dominated navigation cosmological model.The influence of a possible drift(wind) in the navigation cosmological model makes the spacetime geometry change from Riemannian to Finslerian.The evolut...We investigate a matter dominated navigation cosmological model.The influence of a possible drift(wind) in the navigation cosmological model makes the spacetime geometry change from Riemannian to Finslerian.The evolution of the Finslerian Universe is governed by the same gravitational field equation with the familiar Friedmann-Robertson-Walker one.However,the change of space geometry from Riemannian to Finslerian supplies us a new relation between the luminosity distant and redshift.It is shown that the Hubble diagram based on this new relation could account for the observations on distant Type Ia supernovae.展开更多
基金Supported by the National Key Research and Development Program of China(Grant No.2016YFA0400200)the National Natural Science Foundation of China(Grants No.11773075)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2016288).
文摘According to models such as panspermia or the Nebula-Relay hypothesis,the ancestors of life on Earth once lived in molecular clouds.Then what are the energy source and bioenergetics for such lifeforms?A new bioenergetic mechanism powered by cosmic ray ionization of hydrogen molecules is proposed and its relation with the origin of chemiosmosis is also discussed in this paper.Based on this mechanism,the Last Universal Common Ancestor may be a type of lifeform that utilizes hydrogen molecules as donors of electron transport chains.
基金Project(61503077)supported by the National Natural Science Foundation of ChinaProject(BK20130628)supported by the Jiangsu Natural Science Foundation,China
文摘Traditional parafoil homing usually uses a point as object. As the mobility of parafoil is limited by its glide ratio and wind, in some cases when the parafoil scatter area is large, or the glide ratio of parafoil is small, the deviation of its landing point to object point will be arduous to control. Accordingly, during these situations, when parafoil is used in recovery of spacecraft or satellite, the landing area of parafoil can be set as a rectangle, and the object of parafoil can be set as a line segment. The thesis of this work is designing an algorithm for parafoil homing using line segment as object. The algorithm of wind velocity and direction calculation in different flying segments was also investigated. The algorithm designed navigates the parafoil to land into the predestined area and largely reduce the probability of recovery loads falling to unwanted area to damage houses and people.
文摘When Merlin first appears in Chaviano＇s Fables of an Extraterrestrial Grandmother as the wizard Soio, he reflects the imagination of Ana, the adolescent protagonist of the science fiction novel as she is in the process of writing the very novel the reader is reading. Later she will discover that her fictional creations are not the invention of her imagination but exist autonomously in parallel universes and are using her as a vehicle of inter-dimensional travel through time and space. Soio/Merlin gazes into his crystal ball, a microcosm that gathers the space-time energy fields of the parallel universes, and sees visions of the protagonists whose modes of existence are real in one and fictional in another parallel universe. Merlin is a Druid in exile from the Neolithic world of Celtic Britain who has crossed over from earthly life to existence in Rybel, a parallel universe. He had crossed over by lining up the Stone of the Past and the Mirror of the Future at the great circle of Stonehenge. The stone circle functioned as an astronomical observatory. Stonehenge is a microcosm, a circle that reflects and coordinates the larger circle of the universe, symbolized and embodied in the sphere or crystal ball that Merlin transmits to Ana in the form of the novel being read. All the characters are trying to coordinate dimensions of space and time in order to fly from one parallel universe to another. Chaviano emphasizes crossing boundaries of time and space. Her characters live in one world but belonging to another, yearn to make contact with the forces of the universe that will bring them home. Chaviano＇s use of the Merlin legend is original and takes into account archaeological evidence about the Celts, Druids, and Stonehenge.
基金supported by the Ministry of Science and Technology National Basic Science Program (973) (Grant No. 2012CB821804)the National Natural Science Foundation of China (Grant Nos. 10935013,11075083,11175093,11222545 and 11375092)+4 种基金Zhejiang Provincial Natural Science Foundation of China (Grant Nos. Z6100077 and R6110518)the FANEDD (Grant No. 200922)the Hunan Provincial Natural Science Foundation of China (Grant No. 11JJ7001)the SRFDP (Grant No. 20124306110001)partially supported by China Postdoc (Grant No. 2013M530541)
文摘There is an apparent tension between cosmological parameters obtained from Planck cosmic microwave background radiation observations and that derived from the observed magnitude-redshift relation for the type Ia supernova （SNe Ia）. Here, we show that the tension can be alleviated, if we first calibrate, with the help of the distance-duality relation, the light-curve fitting parameters in the distance estimation in SNe Ia observations with the angular diameter distance data of the galaxy clusters and then re-estimate the distances for the SNe Ia with the corrected fitting parameters. This was used to explore their cosmological implications in the context of the spatially fiat cosmology. We find a higher value for the matter density parameter, Ωm, as compared to that from the original SNLS3, which is in agreement with Planck observations at 68.3% confidence. Therefore, the tension between Planck measurements and SNe Ia observations regarding Ωm can be effectively alleviated without invoking new physics or resorting to extensions for the standard concordance model. Moreover, with the absolute magnitude of a fiducial SNe Ia, M, determined first, we obtained a constraint on the Hubble constant with SNLS3 alone, which is also consistent with Planck.
基金supported by the National Natural Science Foundation of China under the Distinguished Young Scholar (Grant Nos.10825313 and 11073005)the Ministry of Science and Technology National Basic Science Program (Project 973) (Grant No.2012CB821804)+1 种基金the Fundamental Research Funds for the Central UniversitiesScientific Research Foundation of Beijing Normal University
文摘The validity of distance duality relation, η = D L (z)(1 + z) 2 /D A (z) = 1, an exact result required by the Etherington reciprocity theorem, where D A (z) and D L (z) are the angular and luminosity distances, plays an essential part in cosmological observations and model constraints. In this paper, we investigate some consequences of such a relation by assuming η a constant or a function of the redshift. In order to constrain the parameters concerning η, we consider two groups of cluster gas mass fraction data including 52 X-ray luminous galaxy clusters observed by Chandra in the redshift range from 0.3 to 1.273 and temperature range T gas > 4 keV, under the assumptions of two different temperature profiles. We find that the constant temperature profile is in relatively good agreement with no violation of the distance duality relation for both parameterizations of η, while the one with temperature gradient (the Vikhlinin et al. temperature profile) seems to be incompatible even at 99% CL.
基金supported by the National Natural Science Foundation of China (Grant No.11103004)the Foundation for the Authors of National Excellent Doctoral Dissertations of China (Grant No.201225)
文摘By phenomenologically describing the high-redshift star formation history, i.e., ,ρ.（z） oc [（1 ＋z）/4.5]-% and semi-analytically calculating the fractions of high-redshift Pop I/II and Pop II! stars, we investigate the contributions from both high-redshfit Pop I/II and Pop II/stars to the observed near-infrared （3 μm 〈// 〈 5 μm） excess in the cosmic infrared background emission. In order to account for the observational level of the near-infrared excess, the power-law index or of the assumed star formation history is constrained to within the range of 0 ≤a≤1. Such a constraint is obtained under the condition that the viral temperature of dark matter halos belongs to the range of 500 K ≤ Tvir≤ 104 K.
基金funded by the Strategic Priority Science and Technology Projects in Space Science of Chinese Academy of Sciences(CAS)supported by the National Natural Science Foundation of China(11921003,11903084,12003076,12022503,12103094,and 12220101003)+7 种基金the Strategic Priority Science and Technology Projects of CAS(XDA15051100)the CAS Project for Young Scientists in Basic Research(YSBR-061)the Youth Innovation Promotion Association of CASthe Natural Science Foundation of Jiangsu Province(BK20201107)the Program for Innovative Talents and Entrepreneur in Jiangsusupported by the Swiss National Science Foundation(SNSF),Switzerlandthe National Institute for Nuclear Physics(INFN),Italythe European Research Council(ERC)under the European Unions Horizon 2020 research and innovation programme(851103)。
文摘Boron nuclei in cosmic rays(CRs)are believed to be mainly produced by the fragmentation of heavier nuclei,such as carbon and oxygen,via collisions with the interstellar matter.Therefore,the boron-tocarbon flux ratio(B/C)and the boron-to-oxygen flux ratio(B/O)are very essential probes of the CR propagation.The energy dependence of the B/C ratio from previous balloon-borne and space-based experiments can be well described by a single power-law up to about 1 TeV/n within uncertainties.This work reports direct measurements of B/C and B/O in the energy range from 10 Ge V/n to 5.6 TeV/n with 6 years of data collected by the Dark Matter Particle Explorer,with high statistics and well controlled systematic uncertainties.The energy dependence of both the B/C and B/O ratios can be well fitted by a broken power-law model rather than a single power-law model,suggesting the existence in both flux ratios of a spectral hardening at about 100 Ge V/n.The significance of the break is about 5.6σand 6.9σfor the GEANT4 simulation,and 4.4σand 6.9σfor the alternative FLUKA simulation,for B/C and B/O,respectively.These results deviate from the predictions of conventional turbulence theories of the interstellar medium(ISM),which point toward a change of turbulence properties of the ISM at different scales or novel propagation effects of CRs,and should be properly incorporated in the indirect detection of dark matter via anti-matter particles.
基金Supported by National Natural Science Foundation of China under Grant Nos.10525522 and 10875129
文摘We investigate a matter dominated navigation cosmological model.The influence of a possible drift(wind) in the navigation cosmological model makes the spacetime geometry change from Riemannian to Finslerian.The evolution of the Finslerian Universe is governed by the same gravitational field equation with the familiar Friedmann-Robertson-Walker one.However,the change of space geometry from Riemannian to Finslerian supplies us a new relation between the luminosity distant and redshift.It is shown that the Hubble diagram based on this new relation could account for the observations on distant Type Ia supernovae.
