We make use of the images from the Sloan Digital Sky Survey Stripe 82（Stripe 82） to present an analysis of r band surface brightness profiles and radial color gradients（g-r,u-r） in our sample of 111 nearby early-t...We make use of the images from the Sloan Digital Sky Survey Stripe 82（Stripe 82） to present an analysis of r band surface brightness profiles and radial color gradients（g-r,u-r） in our sample of 111 nearby early-type galaxies（ETGs） .Thanks to the Stripe 82 images,each of which is co-added from about 50 single frames,we are able to pay special attention to the low-surface-brightness areas（LSB areas） of the galaxies.The LSB areas affect the Sérsic fittings and concentration indices by making both of the indices less than the typical values for ETGs.In the Sérsic fits to all the surface brightness profiles,we found some Sérsic indices that range from 1.5 to 2.5,much smaller than those of typical de Vaucouleur profiles and relatively close to those of exponential disks,and some others much larger than four but still with accurate fitting.Two galaxies cannot be fitted with a single Sérsic profile,but once we try double Sérsic profiles,the fittings are improved：one with a profile relatively close to the de Vaucouleur law in the inner area and a profile relatively close to an exponential law in the LSB area,the other with a nice fitting in the inner area but still having a failed fitting in the outer area.About 60%of the sample has negative color gradients（red-core） within 1.5Re,much more than the approximately 10%positive ones（blue-core） within the same radius.However,taking into account the LSB areas,we find that the color gradients are not necessarily monotonic：about one third of the red-core（or blue-core） galaxies have positive（or negative） color gradients in the outer areas. So LSB areas not only make ETGs’Sérsic profiles deviate from de Vaucouleur ones and shift to the disk end,but also reveal that quite a number of ETGs have opposite color gradients in inner and outer areas.These outcomes remind us of the necessity of double-Sérsic fitting.These LSB phenomena may be interpreted by mergers and thus have different metallicity in the outer areas.Isophotal parameters are also discussed briefly in this paper with the following conclusion：there are more disky nearby ETGs that are identified than boxy ones.展开更多
Controlling the construction of physical colors on the surfaces of transparent dielectric crystals is crucial for surface coloration and anti-counterfeiting applications.In this study,we present a novel approach to cr...Controlling the construction of physical colors on the surfaces of transparent dielectric crystals is crucial for surface coloration and anti-counterfeiting applications.In this study,we present a novel approach to creating stable physical colors on the surface of lithium niobate crystals by combining gold ion implantation with laser direct writing technologies.The interaction between the laser,the implanted gold nanoparticles,and the crystal lattice induces permanent,localized modifications on the crystal surface.By fine-tuning the laser direct writing parameters,we reshaped the gold nanoparticles into spheres of varying sizes on the crystal surface,resulting in the display of red,green,blue,and pale-yellow colors.We investigated the influence of the implanted Au nanoparticles-particularly their localized surface plasmon resonances-on the modifications of the lithium niobate crystal lattice during the laser writing process using confocal Raman spectroscopy and high-resolution transmission electron microscopy.Our findings reveal that the embedded Au nanoparticles play a pivotal role in altering the conventional light-matter interaction between the crystal lattice and the laser,thereby facilitating the generation of surface colors.This work opens new avenues for the development of vibrant surface colors on transparent dielectric crystals.展开更多
We investigate the radial color gradients of galactic disks using a sample of - 20 000 face-on spiral galaxies selected from the fourth data release of the Sloan Digital Sky Survey （SDSS-DR4）. We combine galaxies wi...We investigate the radial color gradients of galactic disks using a sample of - 20 000 face-on spiral galaxies selected from the fourth data release of the Sloan Digital Sky Survey （SDSS-DR4）. We combine galaxies with similar concentrations, sizes and luminosities to construct composite galaxies, and then measure their color profiles by stacking the azimuthally averaged radial color profiles of all the member galaxies. Except for the smallest galaxies （R50 〈 3 kpc）, almost all galaxies show negative disk color gradients with mean 9 - r gradient Ggr = -0.006 magkpc-1 and r - z gradient Grz = -0.018 mag kpc^-1. The disk color gradients are independent of the morphological types of galaxies and strongly dependent on the disk surface brightness μd, with lower surface brightness galactic disks having steeper color gradients. We quantify the intrinsic correlation between color gradients and surface brightness as Ggr = -0.011μd ＋ 0.233 and Grz - -0.015μd ＋ 0.324. These quantified correlations provide tight observational constraints on the formation and evolution models of spiral galaxies.展开更多
A portable near infrared spectroscopy system was developed for assessing the quality of Nanfeng mandarin fruit.One hundred and fifty-three Nanfeng mandarin samples were used to measure the performance of the system.Se...A portable near infrared spectroscopy system was developed for assessing the quality of Nanfeng mandarin fruit.One hundred and fifty-three Nanfeng mandarin samples were used to measure the performance of the system.Several pretreatment methods were adopted to process the spectra.Then Support Vector Machine(SVM),Back Propagation Neural Network(BPNN)and Partial Least Square(PLS)were used to build models for soluble solids content(SSC),titratable acidity(TA),vitamin C and surface color.The best results were obtained by SVM.The correlation coefficient(R)and root mean square error of prediction(RMSEP)were(0.93,0.65°Brix),(0.66,0.09%),(0.81,2.7mg/100g)and(0.57,0.81)for SSC,TA,vitamin C and color,respectively.The results demonstrated that the portable near infrared spectroscopy was feasible for determining the Nanfeng mandarin quality nondestructively.展开更多
The degree-day method is widely used to determine energy consumption but cannot be directly applied to poultry buildings without improvements in its accuracy.This study was designed to optimize the degreeday calculati...The degree-day method is widely used to determine energy consumption but cannot be directly applied to poultry buildings without improvements in its accuracy.This study was designed to optimize the degreeday calculation and proposes a solar-air degree-day method,which can be used to calculate the cooling and heating degree-days and the annual cooling and heating loads under different climate conditions for poultry buildings.In this paper,the solar-air degree-day method was proposed,which considers the effects of solar radiation with different wall orientations and surface colors.Five Chinese cities,Harbin,Beijing,Chongqing,Kunming and Guangzhou,were selected to represent different climate zones to determine the solar-air degreedays.The heating and cooling energy requirements for different climates were compared by DeST(Designer’s Simulation Toolkit)simulation and the solar-air degreeday method.Approaches to decrease energy consumption were developed.The results showed that the maximum relative error was less than 10%,and the new method was not significantly different from the DeST simulation(P>0.05).The accuracy of calculating energy requirements was improved by the solar-air degree-day method in the different climate zones.Orientation and surface color effects on energy consumption need to be considered,and external walls of different orientations should have different surface colors.展开更多
基金Supported by the National Fund for Fostering Talents of Basic Sciences of China
文摘We make use of the images from the Sloan Digital Sky Survey Stripe 82（Stripe 82） to present an analysis of r band surface brightness profiles and radial color gradients（g-r,u-r） in our sample of 111 nearby early-type galaxies（ETGs） .Thanks to the Stripe 82 images,each of which is co-added from about 50 single frames,we are able to pay special attention to the low-surface-brightness areas（LSB areas） of the galaxies.The LSB areas affect the Sérsic fittings and concentration indices by making both of the indices less than the typical values for ETGs.In the Sérsic fits to all the surface brightness profiles,we found some Sérsic indices that range from 1.5 to 2.5,much smaller than those of typical de Vaucouleur profiles and relatively close to those of exponential disks,and some others much larger than four but still with accurate fitting.Two galaxies cannot be fitted with a single Sérsic profile,but once we try double Sérsic profiles,the fittings are improved：one with a profile relatively close to the de Vaucouleur law in the inner area and a profile relatively close to an exponential law in the LSB area,the other with a nice fitting in the inner area but still having a failed fitting in the outer area.About 60%of the sample has negative color gradients（red-core） within 1.5Re,much more than the approximately 10%positive ones（blue-core） within the same radius.However,taking into account the LSB areas,we find that the color gradients are not necessarily monotonic：about one third of the red-core（or blue-core） galaxies have positive（or negative） color gradients in the outer areas. So LSB areas not only make ETGs’Sérsic profiles deviate from de Vaucouleur ones and shift to the disk end,but also reveal that quite a number of ETGs have opposite color gradients in inner and outer areas.These outcomes remind us of the necessity of double-Sérsic fitting.These LSB phenomena may be interpreted by mergers and thus have different metallicity in the outer areas.Isophotal parameters are also discussed briefly in this paper with the following conclusion：there are more disky nearby ETGs that are identified than boxy ones.
基金supported by the National Natural Science Foundation of China (NSFC) (Grants No. 12274236, 12134009, 12074223)Shandong Provincial Natural Science Foundation (Grants No. 2022HWYQ-047, ZR2024MA041)+3 种基金Taishan Scholars Program of Shandong Province (Grants No. tsqn201909041)“Qilu Young Scholar Program” of Shandong UniversityCore Facility Sharing Platform of Shandong UniversityOpen Foundation of the State Key Laboratory of Fluid Power and Mechatronic Systems
文摘Controlling the construction of physical colors on the surfaces of transparent dielectric crystals is crucial for surface coloration and anti-counterfeiting applications.In this study,we present a novel approach to creating stable physical colors on the surface of lithium niobate crystals by combining gold ion implantation with laser direct writing technologies.The interaction between the laser,the implanted gold nanoparticles,and the crystal lattice induces permanent,localized modifications on the crystal surface.By fine-tuning the laser direct writing parameters,we reshaped the gold nanoparticles into spheres of varying sizes on the crystal surface,resulting in the display of red,green,blue,and pale-yellow colors.We investigated the influence of the implanted Au nanoparticles-particularly their localized surface plasmon resonances-on the modifications of the lithium niobate crystal lattice during the laser writing process using confocal Raman spectroscopy and high-resolution transmission electron microscopy.Our findings reveal that the embedded Au nanoparticles play a pivotal role in altering the conventional light-matter interaction between the crystal lattice and the laser,thereby facilitating the generation of surface colors.This work opens new avenues for the development of vibrant surface colors on transparent dielectric crystals.
基金supported by the National Science Foundation of China(Grant Nos.10573028 and 10803016)the Key Project(Nos.10833005 and 10878003)+1 种基金the Group Innovation Project(No.10821302)the 973 program(Nos.2007CB815402 and 2007CB815403)
文摘We investigate the radial color gradients of galactic disks using a sample of - 20 000 face-on spiral galaxies selected from the fourth data release of the Sloan Digital Sky Survey （SDSS-DR4）. We combine galaxies with similar concentrations, sizes and luminosities to construct composite galaxies, and then measure their color profiles by stacking the azimuthally averaged radial color profiles of all the member galaxies. Except for the smallest galaxies （R50 〈 3 kpc）, almost all galaxies show negative disk color gradients with mean 9 - r gradient Ggr = -0.006 magkpc-1 and r - z gradient Grz = -0.018 mag kpc^-1. The disk color gradients are independent of the morphological types of galaxies and strongly dependent on the disk surface brightness μd, with lower surface brightness galactic disks having steeper color gradients. We quantify the intrinsic correlation between color gradients and surface brightness as Ggr = -0.011μd ＋ 0.233 and Grz - -0.015μd ＋ 0.324. These quantified correlations provide tight observational constraints on the formation and evolution models of spiral galaxies.
基金the National Natural Science Foundation of China(Grant No.60844007,60468002,30560064)New Century Excellent Talents in University(NCET-06-0575)+1 种基金National Science and Technology Support Plan(2008BAD96B04,2006BAD11A12-07)Natural Science Foundation of Jiangxi Provincial(2008GQN0029,2007GZN0266,2007-130).
文摘A portable near infrared spectroscopy system was developed for assessing the quality of Nanfeng mandarin fruit.One hundred and fifty-three Nanfeng mandarin samples were used to measure the performance of the system.Several pretreatment methods were adopted to process the spectra.Then Support Vector Machine(SVM),Back Propagation Neural Network(BPNN)and Partial Least Square(PLS)were used to build models for soluble solids content(SSC),titratable acidity(TA),vitamin C and surface color.The best results were obtained by SVM.The correlation coefficient(R)and root mean square error of prediction(RMSEP)were(0.93,0.65°Brix),(0.66,0.09%),(0.81,2.7mg/100g)and(0.57,0.81)for SSC,TA,vitamin C and color,respectively.The results demonstrated that the portable near infrared spectroscopy was feasible for determining the Nanfeng mandarin quality nondestructively.
基金This work was funded by the National Key R&D Program of China(2018YFD0500700)the China Agricultural Research System(CARS-40).
文摘The degree-day method is widely used to determine energy consumption but cannot be directly applied to poultry buildings without improvements in its accuracy.This study was designed to optimize the degreeday calculation and proposes a solar-air degree-day method,which can be used to calculate the cooling and heating degree-days and the annual cooling and heating loads under different climate conditions for poultry buildings.In this paper,the solar-air degree-day method was proposed,which considers the effects of solar radiation with different wall orientations and surface colors.Five Chinese cities,Harbin,Beijing,Chongqing,Kunming and Guangzhou,were selected to represent different climate zones to determine the solar-air degreedays.The heating and cooling energy requirements for different climates were compared by DeST(Designer’s Simulation Toolkit)simulation and the solar-air degreeday method.Approaches to decrease energy consumption were developed.The results showed that the maximum relative error was less than 10%,and the new method was not significantly different from the DeST simulation(P>0.05).The accuracy of calculating energy requirements was improved by the solar-air degree-day method in the different climate zones.Orientation and surface color effects on energy consumption need to be considered,and external walls of different orientations should have different surface colors.
