The magnetoresistive properties of discontinuous ferromagnetic Fe and Co thin films deposited by electron-beam sputtering onto glass substrates at room temperature were investigated. Tunnel magnetoresistance(MR) was o...The magnetoresistive properties of discontinuous ferromagnetic Fe and Co thin films deposited by electron-beam sputtering onto glass substrates at room temperature were investigated. Tunnel magnetoresistance(MR) was observed for all of the as-deposited samples. The maximum MR was observed for Fe thin films with an effective thickness of 17 nm. In the case of the Co thin films, the annealing process led to a change of the type of MR to anisotropic at Co film thicknesses(dCo) of 15 ≤ d_(Co) ≤ 25 nm and to positive isotropic at thicknesses of d_(Co) < 15 nm. By contrast, the MR type of Fe thin films did not change.展开更多
We analyze the frequencies of three known roAp stars,TIC 96315731,TIC 72392575,and TIC 318007796,using the light curves from the Transiting Exoplanet Survey Satellite.For TIC 96315731,the rotational and pulsational fr...We analyze the frequencies of three known roAp stars,TIC 96315731,TIC 72392575,and TIC 318007796,using the light curves from the Transiting Exoplanet Survey Satellite.For TIC 96315731,the rotational and pulsational frequencies are 0.1498360 day^(-1)and 165.2609 day^(-1),respectively.In the case of TIC 72392575,the rotational frequency is 0.25551 day^(-1).We detect a quintuplet of pulsation frequencies with a center frequency of135.9233 day^(-1),along with two signals within the second pair of rotational sidelobes of the quintuplet separated by the rotation frequency.These two signals may correspond to the frequencies of a dipole mode.In TIC318007796,the rotational and pulsational frequencies are 0.2475021 day^(-1),192.73995 day^(-1),and196.33065 day^(-1),respectively.Based on the oblique pulsator model,we calculate the rotation inclination(i)and magnetic obliquity angle(b)for the stars,which provide the geometry of the pulsation modes.Combining the phases of the frequency quintuplets,the pulsation amplitude and phase modulation curves,and the results of spherical harmonic decomposition,we conclude that the pulsation modes of frequency quintuplets in TIC96315731,TIC 72392575,and TIC 318007796 correspond to distorted dipole mode,distorted quadrupole mode,and distorted dipole mode,respectively.展开更多
During the long term evolution of globular clusters(GCs), some member stars are lost to the field. The recently found nitrogen-rich(N-rich) metal-poor field stars are promising candidates of these GC escapees, since N...During the long term evolution of globular clusters(GCs), some member stars are lost to the field. The recently found nitrogen-rich(N-rich) metal-poor field stars are promising candidates of these GC escapees, since N enhancement is the fingerprint of chemically enhanced populations in GCs. In this work, we discuss the possibility of identifying N-rich metal-poor field stars with the upcoming Chinese Space Station Telescope(CSST). We focus on the main survey camera with NUV, u, g, r, i, z, y filters and slitless spectrograph with a resolution about 200.The combination of UV sensitive equipment and prominent N-related molecular lines in the UV band bodes well for the identification: the color–color diagram of(u-g) versus(g-r) is capable of separating N-rich field stars from normal halo stars, if metallicity can be estimated without using the information on u-band photometry.Besides, the synthetic spectra show that a signal-to-noise ratio of 10 is sufficient to identify N-rich field stars. In the near future, a large sample of N-rich field stars found by CSST, combined with state-of-the-art N-body simulations will be crucial to deciphering GC-Galaxy co-evolution.展开更多
We measure the significance of thermally pulsing asymptotic giant branch(TP-AGB)stars via the spectral energy distributions(SEDs)of a sample of post-starburst(PSB)galaxies at z=0.2-0.7.Using ground-and space-based pho...We measure the significance of thermally pulsing asymptotic giant branch(TP-AGB)stars via the spectral energy distributions(SEDs)of a sample of post-starburst(PSB)galaxies at z=0.2-0.7.Using ground-and space-based photometry from the 3D-HST catalog,as well as associated near-infrared(NIR)Hubble Space Telescope(HST)slitless grism spectroscopy,we evaluate the importance of TP-AGB stars in the SEDs of 177 PSB galaxies by fitting simple stellar populations with different levels of TP-AGB contributions.The grism spectra,despite their low resolution of R~100,enable the detection of molecular features specific to TP-AGB stars and thus improve constraints on their contribution.A majority(~70%)of galaxies in the PSB sample show features indicative of TPAGB stars,while the remainder does not and they are well fit by Bruzual&Charlot TP-AGB light models.Stacked spectra of sources classified to be the best fit by TP-AGB heavy/mild models reveal strong detections of NIR molecular features associated with TP-AGB stars.Additionally,we observe a tentative trend with redshift where more TP-AGB heavy galaxies are observed in the higher redshift PSB galaxy population.Finally,neglecting the contribution of TP-AGB stars can yield an over-prediction of stellar masses measured in the K-band ranging from 0.13-0.23 dex.展开更多
Some problems of groundwater development in the Niger Delta ranging from negligence to geological peculiarities are examined to highlight the importance and application of geologic knowledge and research for decision ...Some problems of groundwater development in the Niger Delta ranging from negligence to geological peculiarities are examined to highlight the importance and application of geologic knowledge and research for decision making and averting failure in groundwater development for provisional use. Although the geology and hydrogeologic properties of the aquifer system in the Niger Delta immensely favors groundwater development, there are several recorded cases of failed groundwater development projects poor water quality, dry boreholes and boreholes with surprisingly low yield which could have been avoided. This is due to the perception that since groundwater is prolific, geologic and locational peculiarities can be ignored. This research has highlighted the importance of the knowledge of the hydrogeology of the different geologic units as significant factor in the success of groundwater projects through the correlation of past research of geologic units and groundwater potentials, quality and challenges with the present projects implemented in some of the locations. Cases where groundwater projects are executed with wrong exploration options and without consideration of the peculiarity of the geologic units of the project area, including engagement of incompetent contractors, and negligence to the existing regulatory framework for groundwater development in Nigeria are presented. In order to promote sustainable groundwater development and management in the Niger Delta, this research highlights and recommends the pragmatic use of geologic information including various technical, institutional, regulatory and management measures which have the capacity to avert challenges in groundwater development for provisional use.展开更多
The six antigens of Cysticercus cellulosae: CFag, CSag, CBWag, CWag, UCWag and TSag were prepared respectively. The amino acids of the antigens were determined quantitative by automatic amino acid analyzer. The relati...The six antigens of Cysticercus cellulosae: CFag, CSag, CBWag, CWag, UCWag and TSag were prepared respectively. The amino acids of the antigens were determined quantitative by automatic amino acid analyzer. The relationship of original reaction was confirmed between amino acids and antigens. The results showed that there were 17 amino acids among all of the antigens. There were no significant difference (P >0.05) of Asp, Clu, Lys, His in composition of all antigens by data analysis software SPSS. There are also no significant difference (P >0.05) in the composition of all amino acids between CSag and CBWag. The composition of Thr, Ser, Tyr, Ved, Pro in UCWag shows significant difference (P<0.05) with other antigens. The sensitivity and peculiarity of UCWag are higher than that of the others. Pro and Glu show significant linear correspondence with sensitivity and peculiarity of antigens respectively.展开更多
The effects of soil aeration on physiological characters and root tuber yield of Ipomoea batatas (L.) Lam. CV Lushu7 and Xushu18 were studied. The results showed that soil aeration improvement could increase ATP conte...The effects of soil aeration on physiological characters and root tuber yield of Ipomoea batatas (L.) Lam. CV Lushu7 and Xushu18 were studied. The results showed that soil aeration improvement could increase ATP content and ATPase activity in functional leaves and root tubers and ABA content in root tubers. It also accelerated the transportation of 14C-photosynthate from leaves to root tubers and enhanced dry matter distribution in root tubers and thus root tuber yield was significantly raised. The role of ATP, ATPase and ABA in accelerating the transportation of 14C-photosynthate was discussed based on the changes of soluble carbonhydrate content in sweet potato plant.展开更多
With the development of urban construction and improvement of living standard, modern people have had higher requirements on culture. National Maritime Museum collects and displays maritime culture and civilization of...With the development of urban construction and improvement of living standard, modern people have had higher requirements on culture. National Maritime Museum collects and displays maritime culture and civilization of China, it is a signifi cant cultural facility in New Binhai District of Tianjin. The museum shows us the splendid picture of yel ow terrestrial civilization and blue maritime civilization over the past 2,000 years in China. Landscape design outside the exhibition hall of the museum has the integration of culture and museum as the starting point, and makes brand-new explorations in landscape humanistic care and landscape designs of green buildings.展开更多
Ⅰ.Each of the statements below is followed by four alternative answers.Choose the one that wouldbest complete the statement.1.Polysemy is a common feature peculiar to ___.A.English only B.Chinese only C.all natural l...Ⅰ.Each of the statements below is followed by four alternative answers.Choose the one that wouldbest complete the statement.1.Polysemy is a common feature peculiar to ___.A.English only B.Chinese only C.all natural languages D.some natural languages2.From the ____ point of view,polysemy is assumed to be the result of growth and development of thesemantic structure of one and same word.A.linguistic B.diachronic C.synchronic D.展开更多
Happy Days,one of Samuel Beckett's renowned works,is remarkable for its absurdity.The paper approaches the predominant feature from such aspects as fragmented characters,disconnected language,peculiar structure an...Happy Days,one of Samuel Beckett's renowned works,is remarkable for its absurdity.The paper approaches the predominant feature from such aspects as fragmented characters,disconnected language,peculiar structure and grotesque stagecraft.展开更多
Two Li-rich candidates,TYC 1338-1410-1 and TYC 2825-596-1,were observed by the new high-resolution echelle spectrograph,LAMOST/HRS.Based on their high-resolution and high-signal-tonoise ratio(SNR)spectra,we derived st...Two Li-rich candidates,TYC 1338-1410-1 and TYC 2825-596-1,were observed by the new high-resolution echelle spectrograph,LAMOST/HRS.Based on their high-resolution and high-signal-tonoise ratio(SNR)spectra,we derived stellar parameters and abundances of 14 important elements for the two candidates.The stellar parameters and lithium abundances indicate that they are Li-rich K-type giants,and having A(Li)NLTE and 2.91 dex,respectively.Our analysis suggests that TYC 1338-1410-1 is probably a red giant branch(RGB)star at the bump stage,while TYC 2825-596-1 is most likely to be a core helium-burning red clump(RC)star.The line profiles of both spectra indicate that the two Li-rich giants are slow rotators and do not show infrared(IR)excess.We conclude that engulfment is not the lithium enrichment mechanism for either star.The enriched lithium of TYC 1338-1410-1 could be created via the Cameron-Fowler mechanism,while the lithium excess in TYC 2825-596-1 could be associated with either non-canonical mixing processes or He-flash.展开更多
1.存在“there”与地点“there”的区分在讨论“there”插入转换规则(There-Insertion)之前,有必要对英语中“there”这个词形的两种不同用法作一区别。例(1)a.There was a student on the plat-form.b.There will be some visitors her...1.存在“there”与地点“there”的区分在讨论“there”插入转换规则(There-Insertion)之前,有必要对英语中“there”这个词形的两种不同用法作一区别。例(1)a.There was a student on the plat-form.b.There will be some visitors heretomorrow.c.There reigns a peculiar silence inhere;展开更多
Strongly Mg-enhanced stars with [Mg/Fe] 〉 1.0 show peculiar abundance patterns and hence are of great interest for our understanding of stellar formation and chemical evolution of the Galaxy. A systematic search for ...Strongly Mg-enhanced stars with [Mg/Fe] 〉 1.0 show peculiar abundance patterns and hence are of great interest for our understanding of stellar formation and chemical evolution of the Galaxy. A systematic search for strongly Mg-enhanced stars based on low-resolution (R≈2000) spectra from the Sloan Digital Sky Survey (SDSS) is carried out by finding the synthetic spectrum that best matches the observed one in the region of Mg I b lines around λ5170 ,A via a profile matching method. The advantage of our method is that fitting parameters are refined by reproducing the [Mg/Fe] ratios of 47 stars from the very precise high-resolution spectroscopic (HRS) analysis by Nissen & Schuster; and these parameters are crucial to the precision and validity of the derived Mg abundances. As a further check of our method, Mg abun- dances are estimated with our method for member stars in four Galactic globular clus- ters (M92, M 13, M3, M71) which cover the same metallicity range as our sample, and the results are in good agreement with those of HRS analysis in the literature. The val- idation of our method is also demonstrated by the agreement of [Mg/Fe] between our values and those of HRS analysis by Aoki et al. Finally, 33 candidates of strongly Mg- enhanced stars with [Mg/Fe]〉 1.0 are selected from 14 850 F and G stars. Follow-up observations will be carried out on these candidates with high-resolution spectroscopy by large telescopes in the near future, so as to check our selection procedure and to perform a precise and detailed abundance analysis and to explore the origins of these stars.展开更多
Object J053253.51–695915.1(J053253)in the Large Magellanic Cloud(LMC)is reported as a young stellar object(YSO).Its chemical abundances reflect the initial composition of the gas cloud in which the star formed.Howeve...Object J053253.51–695915.1(J053253)in the Large Magellanic Cloud(LMC)is reported as a young stellar object(YSO).Its chemical abundances reflect the initial composition of the gas cloud in which the star formed.However,the discovery that this star shows the enhancement of the neutron(n)-capture elements and the higher ratio of the heavier n-capture elements relative to the lighter n-capture elements is puzzling.Using an abundance decomposed method,we explore the astrophysical origins of the n-capture elements in this star.We find that the abundance characteristic of the higher ratio of the heavier n-capture elements to the lighter n-capture elements can be explained by the pollution of the r-process event and the contamination of the s-process material.展开更多
Most close double helium white dwarfs will merge within a Hubble time due to orbital decay by gravitational wave radiation.However,a significant fraction with low mass ratios will survive for a long time as a conseque...Most close double helium white dwarfs will merge within a Hubble time due to orbital decay by gravitational wave radiation.However,a significant fraction with low mass ratios will survive for a long time as a consequence of stable mass transfer.Such stable mass transfer between two helium white dwarfs(He WDs) provides one channel for the production of AM CVn binary stars.In previous calculations of double He WD progenitors,the accreting He WD was treated as a point mass.We have computed the evolution of 16 double He WD models in order to investigate the consequences of treating the evolution of both components in detail.We find that the boundary between binaries having stable and unstable mass transfer is slightly modified by this approach.By comparing with observed periods and mass ratios,we redetermine masses of eight known AM CVn stars by our double He WDs channel,i.e.HM Cnc,AM CVn,V406 Hya,J0926,J1240,GP Com,Gaia14 aae and V396 Hya.We propose that central spikes in the triple-peaked emission spectra of J1240,GP Com and V396 Hya and the surface abundance ratios of N/C/O in GP Com can be explained by the stable double He WD channel.The mass estimates derived from our calculations are used to discuss the predicted gravitational wave signal in the context of the Laser Interferometer Space Antenna(LISA) project.展开更多
Radiative lifetimes of two short-lived levels (i.e. 4f^8 (TF6)6p^1/2 (6, 1/2)11/2,13/2) in Tb Ⅲ are measured by time-resolved laser-induced fluorescence (LIE) technique with a two-step excitation process. Fre...Radiative lifetimes of two short-lived levels (i.e. 4f^8 (TF6)6p^1/2 (6, 1/2)11/2,13/2) in Tb Ⅲ are measured by time-resolved laser-induced fluorescence (LIE) technique with a two-step excitation process. Free Tb Ⅲ ions are produced in a laser-induced plasma. Lifetime values are evaluated with a deconvolution procedure of the timeresolved fluorescence signal with the temporal shape of second-step excitation pulse (about 1 ns). The lifetimes of the 4f^8 (^7F6)6p^1/2 (6, 1/2)11/2 and 4f^8(^7F6)6p^1/2 (6, 1/2)13/2 levels are determined to be 1.9 (2) and 2.0 (2)ns, respectively.展开更多
In selecting methods of liquidation of natural pollution resulted from oil products (OP) in the cold regions, such as in the north coast of the Sea of Okhotsk, it is necessary to take into consideration the peculiarit...In selecting methods of liquidation of natural pollution resulted from oil products (OP) in the cold regions, such as in the north coast of the Sea of Okhotsk, it is necessary to take into consideration the peculiarities of the OP and the object polluted in cold and warm periods. Generally, in cold time snow cover with thickness of 1.0m or more presents, so the OP is partly absorbed by the silt in the snow, then the viscosity of snow is strengthened due to the aggregate of the hard hydrocarbon components (HСС) with negative temperature in the OP. The HCC is the most active when the molecular of carbon atom is less than 10, and could not be harden at the temperature below (-30 ℃). However, in summer time the spilled HCC is partly evaporated, but the tar and asphalt enrich the OP there. In the mountainous regions at the deep deposition of underground water, in summer the OP might be brought by the gas stream in the massifs of the fracture rocks upper on the slope. According to the peculiarities, the methods of fighting the nature, polluted by the OP in the regions of the Sub-Arctic; are explained, and they are representative in the north coast of the Sea of Okhotsk.展开更多
Objective:To determine the frequency of risk factors of congestive cardiac failure in a tertiary care hospital of Peshawar.Methods:This retrospective observational study was conducted in department of Cardiology,Postg...Objective:To determine the frequency of risk factors of congestive cardiac failure in a tertiary care hospital of Peshawar.Methods:This retrospective observational study was conducted in department of Cardiology,Postgraduate Medical Institute,Lady Reading Hospital Peshawar,from March 2005 to September 2007.Relevant information regarding the risk factors of congestive cardiac failure were recorded on questionnaire prepared in accordance with the objectives of the study.Results:1 019 patients with established diagnosis of cardiac failure (based on clinical findings and relevant investigations) were included.Out of total sampling 583 (57.12%) were males and 436(42.78%) were females.The age range of the patients was from 6 years to 82 years with mean age of 48.5 years and mode of age was 45 years.The distribution of causative factors of CCF was:ischemic heart disease(IHD) 36.31%,hypertension 26.30%,dilated cardiomyopathy 10.10%,obstructve and restrictive cardiomyopathies 5.39%,valvular heart diseases(VHD) 9.32%,congenital heart disease like ventricular septal defects(VSD) 4.41%,atrial septal defects(ASD) 0.58%,atrial fibrillation (AF) 2.25%,constrictive pericardidtis 1.07%.Pericardial effusion 0.68%,chronic obstructive pulmonary disease and pulmonary hypertension 1.47%,thyrotoxicosis 0.68%,complete heart block 0.29%and paget disease in 0.09%cases.Conclusion:Ischemic heart disease,hypertension,cardiomypathies,valvular heart disease and congenital heart disease are major contributor to CCF in our patients.展开更多
Infantile cerebral palsy is a nonprogressive central motor disturbance of varied etiology.Thespasmodic type is its main form,accounting for 50—60% of the infants afflicted with the dis-ease.The causal factors includ...Infantile cerebral palsy is a nonprogressive central motor disturbance of varied etiology.Thespasmodic type is its main form,accounting for 50—60% of the infants afflicted with the dis-ease.The causal factors include multifarious conditions arising during parturition and in thepre-and postnatal periods.As yet there is no specific treatment for the disease.We haveused a method of applying prompt pressure to peculiar points in treating it and received sat-isfactory results.展开更多
The effect of formed CH_3NH_3 at the heterojunction on properties of CH_3NH_3PbI_3 material is investigated based on experiment and theoretical calculation. Our calculation results show that the giant dielectric const...The effect of formed CH_3NH_3 at the heterojunction on properties of CH_3NH_3PbI_3 material is investigated based on experiment and theoretical calculation. Our calculation results show that the giant dielectric constant, anomalous hysteresis and long-lasting polarization for CH_3NH_3PbI_3 originate from the formed CH_3NH_3 at the heterojunction. It is found that the induced weak EPS by the reorientation of CH_3NH_3 sub-group along the built-in electric field enables us to effectively increase the ordering of entire lead-halide framework. In addition, the heterojunction has an advantage of channel separation between carrier transport and electron diffusion. These properties of the heterojunction are the main origin of the high efficiency of CH_3NH_3PbI_3 solar cells.展开更多
基金funded by the State Program of the Ministry of Education and Science of Ukraine (0116U002623)
文摘The magnetoresistive properties of discontinuous ferromagnetic Fe and Co thin films deposited by electron-beam sputtering onto glass substrates at room temperature were investigated. Tunnel magnetoresistance(MR) was observed for all of the as-deposited samples. The maximum MR was observed for Fe thin films with an effective thickness of 17 nm. In the case of the Co thin films, the annealing process led to a change of the type of MR to anisotropic at Co film thicknesses(dCo) of 15 ≤ d_(Co) ≤ 25 nm and to positive isotropic at thicknesses of d_(Co) < 15 nm. By contrast, the MR type of Fe thin films did not change.
基金Funding for the TESS mission is provided by the NASA Explorer Programsupport of the National Natural Science Foundation of China(NSFC,grant Nos.U2031204,12373038,12163005,and 12288102)+1 种基金the science research grants from the China Manned Space Project with No.CMSCSST-2021-A10the Natural Science Foundation of Xinjiang Nos.2022D01D85 and 2022TSYCLJ0006。
文摘We analyze the frequencies of three known roAp stars,TIC 96315731,TIC 72392575,and TIC 318007796,using the light curves from the Transiting Exoplanet Survey Satellite.For TIC 96315731,the rotational and pulsational frequencies are 0.1498360 day^(-1)and 165.2609 day^(-1),respectively.In the case of TIC 72392575,the rotational frequency is 0.25551 day^(-1).We detect a quintuplet of pulsation frequencies with a center frequency of135.9233 day^(-1),along with two signals within the second pair of rotational sidelobes of the quintuplet separated by the rotation frequency.These two signals may correspond to the frequencies of a dipole mode.In TIC318007796,the rotational and pulsational frequencies are 0.2475021 day^(-1),192.73995 day^(-1),and196.33065 day^(-1),respectively.Based on the oblique pulsator model,we calculate the rotation inclination(i)and magnetic obliquity angle(b)for the stars,which provide the geometry of the pulsation modes.Combining the phases of the frequency quintuplets,the pulsation amplitude and phase modulation curves,and the results of spherical harmonic decomposition,we conclude that the pulsation modes of frequency quintuplets in TIC96315731,TIC 72392575,and TIC 318007796 correspond to distorted dipole mode,distorted quadrupole mode,and distorted dipole mode,respectively.
基金support from the China Manned Space Project Nos. CMS-CSST-2021-B03,CMS-CSST-2021-A08, and________the National Natural Science Foundation of China under grant No. 12233013,12073090+8 种基金the Natural Science Foundation of Guangdong Province under grant No. 2022A1515010732grant support provided by Proyecto Fondecyt Iniciación No. 11220340ANID Concurso de Fomento a la Vinculación Internacional para Instituciones de Investigación Regionales (Modalidad corta duración) Proyecto No. FOVI210020Joint Committee ESO-Government of Chile 2021 (ORP 023/2021)Becas Santander Movilidad Internacional Profesores 2022, Banco Santander Chilesupport from the National Natural Science Foundation of China through grant 21BAA00619the one-hundred-talent project of Sun Yat-sen Universitythe Fundamental Research Funds for the Central UniversitiesSun Yat-sen University (22hytd09)。
文摘During the long term evolution of globular clusters(GCs), some member stars are lost to the field. The recently found nitrogen-rich(N-rich) metal-poor field stars are promising candidates of these GC escapees, since N enhancement is the fingerprint of chemically enhanced populations in GCs. In this work, we discuss the possibility of identifying N-rich metal-poor field stars with the upcoming Chinese Space Station Telescope(CSST). We focus on the main survey camera with NUV, u, g, r, i, z, y filters and slitless spectrograph with a resolution about 200.The combination of UV sensitive equipment and prominent N-related molecular lines in the UV band bodes well for the identification: the color–color diagram of(u-g) versus(g-r) is capable of separating N-rich field stars from normal halo stars, if metallicity can be estimated without using the information on u-band photometry.Besides, the synthetic spectra show that a signal-to-noise ratio of 10 is sufficient to identify N-rich field stars. In the near future, a large sample of N-rich field stars found by CSST, combined with state-of-the-art N-body simulations will be crucial to deciphering GC-Galaxy co-evolution.
基金based on observation taken by the 3D-HST Treasury Program(GO 12177 and 12328)with NASA/ESA HSToperated by the Association of Universities for Research in Astronomy Inc.,under NASA contract NAS5-26555+1 种基金supported by the National Natural Science Foundation of China(NSFC,Grant No.U1931209)the National Key R&D Program of China(No.2019YFA0405502)。
文摘We measure the significance of thermally pulsing asymptotic giant branch(TP-AGB)stars via the spectral energy distributions(SEDs)of a sample of post-starburst(PSB)galaxies at z=0.2-0.7.Using ground-and space-based photometry from the 3D-HST catalog,as well as associated near-infrared(NIR)Hubble Space Telescope(HST)slitless grism spectroscopy,we evaluate the importance of TP-AGB stars in the SEDs of 177 PSB galaxies by fitting simple stellar populations with different levels of TP-AGB contributions.The grism spectra,despite their low resolution of R~100,enable the detection of molecular features specific to TP-AGB stars and thus improve constraints on their contribution.A majority(~70%)of galaxies in the PSB sample show features indicative of TPAGB stars,while the remainder does not and they are well fit by Bruzual&Charlot TP-AGB light models.Stacked spectra of sources classified to be the best fit by TP-AGB heavy/mild models reveal strong detections of NIR molecular features associated with TP-AGB stars.Additionally,we observe a tentative trend with redshift where more TP-AGB heavy galaxies are observed in the higher redshift PSB galaxy population.Finally,neglecting the contribution of TP-AGB stars can yield an over-prediction of stellar masses measured in the K-band ranging from 0.13-0.23 dex.
文摘Some problems of groundwater development in the Niger Delta ranging from negligence to geological peculiarities are examined to highlight the importance and application of geologic knowledge and research for decision making and averting failure in groundwater development for provisional use. Although the geology and hydrogeologic properties of the aquifer system in the Niger Delta immensely favors groundwater development, there are several recorded cases of failed groundwater development projects poor water quality, dry boreholes and boreholes with surprisingly low yield which could have been avoided. This is due to the perception that since groundwater is prolific, geologic and locational peculiarities can be ignored. This research has highlighted the importance of the knowledge of the hydrogeology of the different geologic units as significant factor in the success of groundwater projects through the correlation of past research of geologic units and groundwater potentials, quality and challenges with the present projects implemented in some of the locations. Cases where groundwater projects are executed with wrong exploration options and without consideration of the peculiarity of the geologic units of the project area, including engagement of incompetent contractors, and negligence to the existing regulatory framework for groundwater development in Nigeria are presented. In order to promote sustainable groundwater development and management in the Niger Delta, this research highlights and recommends the pragmatic use of geologic information including various technical, institutional, regulatory and management measures which have the capacity to avert challenges in groundwater development for provisional use.
文摘The six antigens of Cysticercus cellulosae: CFag, CSag, CBWag, CWag, UCWag and TSag were prepared respectively. The amino acids of the antigens were determined quantitative by automatic amino acid analyzer. The relationship of original reaction was confirmed between amino acids and antigens. The results showed that there were 17 amino acids among all of the antigens. There were no significant difference (P >0.05) of Asp, Clu, Lys, His in composition of all antigens by data analysis software SPSS. There are also no significant difference (P >0.05) in the composition of all amino acids between CSag and CBWag. The composition of Thr, Ser, Tyr, Ved, Pro in UCWag shows significant difference (P<0.05) with other antigens. The sensitivity and peculiarity of UCWag are higher than that of the others. Pro and Glu show significant linear correspondence with sensitivity and peculiarity of antigens respectively.
文摘The effects of soil aeration on physiological characters and root tuber yield of Ipomoea batatas (L.) Lam. CV Lushu7 and Xushu18 were studied. The results showed that soil aeration improvement could increase ATP content and ATPase activity in functional leaves and root tubers and ABA content in root tubers. It also accelerated the transportation of 14C-photosynthate from leaves to root tubers and enhanced dry matter distribution in root tubers and thus root tuber yield was significantly raised. The role of ATP, ATPase and ABA in accelerating the transportation of 14C-photosynthate was discussed based on the changes of soluble carbonhydrate content in sweet potato plant.
文摘With the development of urban construction and improvement of living standard, modern people have had higher requirements on culture. National Maritime Museum collects and displays maritime culture and civilization of China, it is a signifi cant cultural facility in New Binhai District of Tianjin. The museum shows us the splendid picture of yel ow terrestrial civilization and blue maritime civilization over the past 2,000 years in China. Landscape design outside the exhibition hall of the museum has the integration of culture and museum as the starting point, and makes brand-new explorations in landscape humanistic care and landscape designs of green buildings.
文摘Ⅰ.Each of the statements below is followed by four alternative answers.Choose the one that wouldbest complete the statement.1.Polysemy is a common feature peculiar to ___.A.English only B.Chinese only C.all natural languages D.some natural languages2.From the ____ point of view,polysemy is assumed to be the result of growth and development of thesemantic structure of one and same word.A.linguistic B.diachronic C.synchronic D.
文摘Happy Days,one of Samuel Beckett's renowned works,is remarkable for its absurdity.The paper approaches the predominant feature from such aspects as fragmented characters,disconnected language,peculiar structure and grotesque stagecraft.
基金the National Key R&D Program of China(No.2019YFA0405502)the Key Research Program of the Chinese Academy of Sciences under grant No.XDPB09-02+8 种基金the National Natural Science Foundation of China(Grant Nos.11973052,11833006,11473033 and 11603037)the International partnership program’s Key foreign cooperation project,Bureau of International Cooperation,Chinese Academy of Sciences(No.114A32KYSB20160049)supported by the Astronomical Big Data Joint Research Center,co-founded by the National Astronomical Observatories,Chinese Academy of Sciences and Alibaba Cloudpartially supported by the Open Project Program of the Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciencesthe financial support from China Scholarship Council(CSC,No.201604910642)for his study at New Mexico State University in the United States of Americathe supports from Youth Innovation Promotion Association,Chinese Academy of SciencesGuo Shou Jing Telescope(the Large Sky Area Multi-Object Fiber Spectroscopic Telescope LAMOST)is a National Major Scientific Project built by the Chinese Academy of Sciences.Funding for the project has been provided by the National Development and Reform Commissionthe NASA/IPAC Infrared Science Archive,which is funded by the National Aeronautics and Space Administrationthe Wide-field Infrared Survey Explorer,which is a joint project of the University of California,Los Angeles,and the Jet Propulsion Laboratory/California Institute of Technology,funded by the National Aeronautics and Space Administration。
文摘Two Li-rich candidates,TYC 1338-1410-1 and TYC 2825-596-1,were observed by the new high-resolution echelle spectrograph,LAMOST/HRS.Based on their high-resolution and high-signal-tonoise ratio(SNR)spectra,we derived stellar parameters and abundances of 14 important elements for the two candidates.The stellar parameters and lithium abundances indicate that they are Li-rich K-type giants,and having A(Li)NLTE and 2.91 dex,respectively.Our analysis suggests that TYC 1338-1410-1 is probably a red giant branch(RGB)star at the bump stage,while TYC 2825-596-1 is most likely to be a core helium-burning red clump(RC)star.The line profiles of both spectra indicate that the two Li-rich giants are slow rotators and do not show infrared(IR)excess.We conclude that engulfment is not the lithium enrichment mechanism for either star.The enriched lithium of TYC 1338-1410-1 could be created via the Cameron-Fowler mechanism,while the lithium excess in TYC 2825-596-1 could be associated with either non-canonical mixing processes or He-flash.
文摘1.存在“there”与地点“there”的区分在讨论“there”插入转换规则(There-Insertion)之前,有必要对英语中“there”这个词形的两种不同用法作一区别。例(1)a.There was a student on the plat-form.b.There will be some visitors heretomorrow.c.There reigns a peculiar silence inhere;
基金Supported by the National Natural Science Foundation of China
文摘Strongly Mg-enhanced stars with [Mg/Fe] 〉 1.0 show peculiar abundance patterns and hence are of great interest for our understanding of stellar formation and chemical evolution of the Galaxy. A systematic search for strongly Mg-enhanced stars based on low-resolution (R≈2000) spectra from the Sloan Digital Sky Survey (SDSS) is carried out by finding the synthetic spectrum that best matches the observed one in the region of Mg I b lines around λ5170 ,A via a profile matching method. The advantage of our method is that fitting parameters are refined by reproducing the [Mg/Fe] ratios of 47 stars from the very precise high-resolution spectroscopic (HRS) analysis by Nissen & Schuster; and these parameters are crucial to the precision and validity of the derived Mg abundances. As a further check of our method, Mg abun- dances are estimated with our method for member stars in four Galactic globular clus- ters (M92, M 13, M3, M71) which cover the same metallicity range as our sample, and the results are in good agreement with those of HRS analysis in the literature. The val- idation of our method is also demonstrated by the agreement of [Mg/Fe] between our values and those of HRS analysis by Aoki et al. Finally, 33 candidates of strongly Mg- enhanced stars with [Mg/Fe]〉 1.0 are selected from 14 850 F and G stars. Follow-up observations will be carried out on these candidates with high-resolution spectroscopy by large telescopes in the near future, so as to check our selection procedure and to perform a precise and detailed abundance analysis and to explore the origins of these stars.
基金supported by the National Natural Science Foundation of China(Grant Nos.11673007,11547041,11643007 and 11773009)the Natural Science Foundation of Hebei Province(Grant No.A2019208194)。
文摘Object J053253.51–695915.1(J053253)in the Large Magellanic Cloud(LMC)is reported as a young stellar object(YSO).Its chemical abundances reflect the initial composition of the gas cloud in which the star formed.However,the discovery that this star shows the enhancement of the neutron(n)-capture elements and the higher ratio of the heavier n-capture elements relative to the lighter n-capture elements is puzzling.Using an abundance decomposed method,we explore the astrophysical origins of the n-capture elements in this star.We find that the abundance characteristic of the higher ratio of the heavier n-capture elements to the lighter n-capture elements can be explained by the pollution of the r-process event and the contamination of the s-process material.
基金supported by the CAS ‘Light of West China’ program(2015-XBQNA-02)the National Natural Science Foundation of China(NSFC,Grant Nos.10933002,11703001 and 11273007)+5 种基金the Joint Research Fund in Astronomy(U1631236) under cooperative agreement between the NSFC and the Chinese Academy of Sciences(CAS)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB2304100)the China Postdoctoral Science Foundationthe Fundamental Research Funds for the Central UniversitiesThe Armagh Observatory and Planetarium are supported by a grant from the Northern Ireland Department for Communitiessupport from the UK Science and Technology Facilities Council(STFC)(Grant No.ST/M000834/1)
文摘Most close double helium white dwarfs will merge within a Hubble time due to orbital decay by gravitational wave radiation.However,a significant fraction with low mass ratios will survive for a long time as a consequence of stable mass transfer.Such stable mass transfer between two helium white dwarfs(He WDs) provides one channel for the production of AM CVn binary stars.In previous calculations of double He WD progenitors,the accreting He WD was treated as a point mass.We have computed the evolution of 16 double He WD models in order to investigate the consequences of treating the evolution of both components in detail.We find that the boundary between binaries having stable and unstable mass transfer is slightly modified by this approach.By comparing with observed periods and mass ratios,we redetermine masses of eight known AM CVn stars by our double He WDs channel,i.e.HM Cnc,AM CVn,V406 Hya,J0926,J1240,GP Com,Gaia14 aae and V396 Hya.We propose that central spikes in the triple-peaked emission spectra of J1240,GP Com and V396 Hya and the surface abundance ratios of N/C/O in GP Com can be explained by the stable double He WD channel.The mass estimates derived from our calculations are used to discuss the predicted gravitational wave signal in the context of the Laser Interferometer Space Antenna(LISA) project.
基金Supported by the Swedish Natural Science Research Council and the National Natural Science Foundation of China under No 10274025.
文摘Radiative lifetimes of two short-lived levels (i.e. 4f^8 (TF6)6p^1/2 (6, 1/2)11/2,13/2) in Tb Ⅲ are measured by time-resolved laser-induced fluorescence (LIE) technique with a two-step excitation process. Free Tb Ⅲ ions are produced in a laser-induced plasma. Lifetime values are evaluated with a deconvolution procedure of the timeresolved fluorescence signal with the temporal shape of second-step excitation pulse (about 1 ns). The lifetimes of the 4f^8 (^7F6)6p^1/2 (6, 1/2)11/2 and 4f^8(^7F6)6p^1/2 (6, 1/2)13/2 levels are determined to be 1.9 (2) and 2.0 (2)ns, respectively.
文摘In selecting methods of liquidation of natural pollution resulted from oil products (OP) in the cold regions, such as in the north coast of the Sea of Okhotsk, it is necessary to take into consideration the peculiarities of the OP and the object polluted in cold and warm periods. Generally, in cold time snow cover with thickness of 1.0m or more presents, so the OP is partly absorbed by the silt in the snow, then the viscosity of snow is strengthened due to the aggregate of the hard hydrocarbon components (HСС) with negative temperature in the OP. The HCC is the most active when the molecular of carbon atom is less than 10, and could not be harden at the temperature below (-30 ℃). However, in summer time the spilled HCC is partly evaporated, but the tar and asphalt enrich the OP there. In the mountainous regions at the deep deposition of underground water, in summer the OP might be brought by the gas stream in the massifs of the fracture rocks upper on the slope. According to the peculiarities, the methods of fighting the nature, polluted by the OP in the regions of the Sub-Arctic; are explained, and they are representative in the north coast of the Sea of Okhotsk.
文摘Objective:To determine the frequency of risk factors of congestive cardiac failure in a tertiary care hospital of Peshawar.Methods:This retrospective observational study was conducted in department of Cardiology,Postgraduate Medical Institute,Lady Reading Hospital Peshawar,from March 2005 to September 2007.Relevant information regarding the risk factors of congestive cardiac failure were recorded on questionnaire prepared in accordance with the objectives of the study.Results:1 019 patients with established diagnosis of cardiac failure (based on clinical findings and relevant investigations) were included.Out of total sampling 583 (57.12%) were males and 436(42.78%) were females.The age range of the patients was from 6 years to 82 years with mean age of 48.5 years and mode of age was 45 years.The distribution of causative factors of CCF was:ischemic heart disease(IHD) 36.31%,hypertension 26.30%,dilated cardiomyopathy 10.10%,obstructve and restrictive cardiomyopathies 5.39%,valvular heart diseases(VHD) 9.32%,congenital heart disease like ventricular septal defects(VSD) 4.41%,atrial septal defects(ASD) 0.58%,atrial fibrillation (AF) 2.25%,constrictive pericardidtis 1.07%.Pericardial effusion 0.68%,chronic obstructive pulmonary disease and pulmonary hypertension 1.47%,thyrotoxicosis 0.68%,complete heart block 0.29%and paget disease in 0.09%cases.Conclusion:Ischemic heart disease,hypertension,cardiomypathies,valvular heart disease and congenital heart disease are major contributor to CCF in our patients.
文摘Infantile cerebral palsy is a nonprogressive central motor disturbance of varied etiology.Thespasmodic type is its main form,accounting for 50—60% of the infants afflicted with the dis-ease.The causal factors include multifarious conditions arising during parturition and in thepre-and postnatal periods.As yet there is no specific treatment for the disease.We haveused a method of applying prompt pressure to peculiar points in treating it and received sat-isfactory results.
基金Supported by the National Natural Science Foundation of China under Grant No 61875235the Ph.D. Programs Foundation of Ministry of Education of China under Grant No 20130009110008the Beijing Municipal Education Commission Project under Grant No KM201210015008
文摘The effect of formed CH_3NH_3 at the heterojunction on properties of CH_3NH_3PbI_3 material is investigated based on experiment and theoretical calculation. Our calculation results show that the giant dielectric constant, anomalous hysteresis and long-lasting polarization for CH_3NH_3PbI_3 originate from the formed CH_3NH_3 at the heterojunction. It is found that the induced weak EPS by the reorientation of CH_3NH_3 sub-group along the built-in electric field enables us to effectively increase the ordering of entire lead-halide framework. In addition, the heterojunction has an advantage of channel separation between carrier transport and electron diffusion. These properties of the heterojunction are the main origin of the high efficiency of CH_3NH_3PbI_3 solar cells.