Based on an accuracy analysis of two-stream approximations, an improved δ-Eddington ap-proximation is developed. The approximation has much better accuracy than all exiting two-stream ap-proximations as the optical d...Based on an accuracy analysis of two-stream approximations, an improved δ-Eddington ap-proximation is developed. The approximation has much better accuracy than all exiting two-stream ap-proximations as the optical depth is less than unity. As the surface reflectance is zero and the opticaldepth is less than unity, errors in both transmission and reflection calculated by the present approxima-tion are more one time less than those by other two-stream approximations. In the case of aerosol opti-cal depth of【1, surface reflectance of 【 0.6, solar zenith angle of 【 78°and aerosol imaginary indexof 【 0.05, transmission and reflection errors calculated by the improved δ-Eddington approximationare generally less than 3.5% and 2.6%, respectively. The errors are over 41% and one times lessthan those by Eddington or δ-Eddington.展开更多
We give the Buchdahl stability bound in Eddington-inspired Born-Infeld(EiBI)gravity.We show that this bound depends on an energy condition controlled by the model parameter K.From this bound,we can constrain κ≤10~8 ...We give the Buchdahl stability bound in Eddington-inspired Born-Infeld(EiBI)gravity.We show that this bound depends on an energy condition controlled by the model parameter K.From this bound,we can constrain κ≤10~8 m^2 if a neutron star with a mass around 3 M is observed in the future.In addition,to avoid the potential pathologies in EiBI,a Hagedorn-like equation of state associated with κ at the center of a compact star is inevitable,which is similar to the Hagedorn temperature in string theory.展开更多
A new parameterization of canopy asymmetry factor on phase function,which is dependent on the leaf normal distribution and leaf reflection/transmission,is derived. This new parameterization is much more accurate than ...A new parameterization of canopy asymmetry factor on phase function,which is dependent on the leaf normal distribution and leaf reflection/transmission,is derived. This new parameterization is much more accurate than the existing scheme. In addition,the new solutions for both the diffuse and direct radiation can be obtained using the Eddington approximation. It is found that the direct radiation can be described as a function of the diffuse radiation. This new approach offers a substantial improvement in accuracy,as compared with the hemispheric constant method,for both isotropic and anisotropic cases. Given the analytical nature of the solution and its high accuracy,we recommend the new parameterization for application in land surface radiation modeling.展开更多
The article relates to decades-old problem of the mysterious coincidence of various Large numbers of magnitude ranging from 1040 to 10120 which sometimes appears in cosmology and quantum physics. Using well-known clas...The article relates to decades-old problem of the mysterious coincidence of various Large numbers of magnitude ranging from 1040 to 10120 which sometimes appears in cosmology and quantum physics. Using well-known classical relations as well as the ideal Schwarzschild solution the exact relations of various large numbers, fine structure constant α and were found. The new Largest number law is claimed. The hypothetical approximations of the Hubble parameter—68.7457(82) km/s/Mpc, Hubble radius—14.2330(17) Gly, and some others were proposed. The exact formulae supporting P. Diracs Large number hypothesis and H. Weyls proposition were found. It is shown that all major physical constants with length dimension (from Compton wave length of universe through Planck and atomic scale up to Hubble sphere radius) could be derived from each other, and the table of the specific conversion rules has been developed. The model shows that Eddington-Weinberg relation can be transformed to precise identity. It is shown that both Bekenstein universal entropy bound and Hooft-Susskind holographic entropy bound are equal to the Largest number doubled.展开更多
文摘Based on an accuracy analysis of two-stream approximations, an improved δ-Eddington ap-proximation is developed. The approximation has much better accuracy than all exiting two-stream ap-proximations as the optical depth is less than unity. As the surface reflectance is zero and the opticaldepth is less than unity, errors in both transmission and reflection calculated by the present approxima-tion are more one time less than those by other two-stream approximations. In the case of aerosol opti-cal depth of【1, surface reflectance of 【 0.6, solar zenith angle of 【 78°and aerosol imaginary indexof 【 0.05, transmission and reflection errors calculated by the improved δ-Eddington approximationare generally less than 3.5% and 2.6%, respectively. The errors are over 41% and one times lessthan those by Eddington or δ-Eddington.
基金Supported in part by National Center for Theoretical Sciences and Mo ST(Mo ST-104-2112-M-007-003-MY3 and Mo ST-107-2119-M-007-013-MY3)Academia Sinica Career Development Award Program(AS-CDA-105-M06)
文摘We give the Buchdahl stability bound in Eddington-inspired Born-Infeld(EiBI)gravity.We show that this bound depends on an energy condition controlled by the model parameter K.From this bound,we can constrain κ≤10~8 m^2 if a neutron star with a mass around 3 M is observed in the future.In addition,to avoid the potential pathologies in EiBI,a Hagedorn-like equation of state associated with κ at the center of a compact star is inevitable,which is similar to the Hagedorn temperature in string theory.
基金supported by the National Natural Science Foundation of China (Grant Nos.41305004,41675003 and 91537213)the PAPD (Priority Academic Program Development) of Jiangsu Higher Education Institutions
文摘A new parameterization of canopy asymmetry factor on phase function,which is dependent on the leaf normal distribution and leaf reflection/transmission,is derived. This new parameterization is much more accurate than the existing scheme. In addition,the new solutions for both the diffuse and direct radiation can be obtained using the Eddington approximation. It is found that the direct radiation can be described as a function of the diffuse radiation. This new approach offers a substantial improvement in accuracy,as compared with the hemispheric constant method,for both isotropic and anisotropic cases. Given the analytical nature of the solution and its high accuracy,we recommend the new parameterization for application in land surface radiation modeling.
文摘The article relates to decades-old problem of the mysterious coincidence of various Large numbers of magnitude ranging from 1040 to 10120 which sometimes appears in cosmology and quantum physics. Using well-known classical relations as well as the ideal Schwarzschild solution the exact relations of various large numbers, fine structure constant α and were found. The new Largest number law is claimed. The hypothetical approximations of the Hubble parameter—68.7457(82) km/s/Mpc, Hubble radius—14.2330(17) Gly, and some others were proposed. The exact formulae supporting P. Diracs Large number hypothesis and H. Weyls proposition were found. It is shown that all major physical constants with length dimension (from Compton wave length of universe through Planck and atomic scale up to Hubble sphere radius) could be derived from each other, and the table of the specific conversion rules has been developed. The model shows that Eddington-Weinberg relation can be transformed to precise identity. It is shown that both Bekenstein universal entropy bound and Hooft-Susskind holographic entropy bound are equal to the Largest number doubled.
