BVRI CCD photometry of the poorly studied open cluster NGC 6724 has been carried out down to a limiting magnitude of V-20 mag. The stars of the cluster have been observed using the Newtonian focus （f/4.84） of the 74...BVRI CCD photometry of the poorly studied open cluster NGC 6724 has been carried out down to a limiting magnitude of V-20 mag. The stars of the cluster have been observed using the Newtonian focus （f/4.84） of the 74-inch telescope at Kottamia Astronomical Observatory in Egypt. Also, the 2MASS - JHK system is used to confirm the results we obtained. The main photometric parameters have been estimated for the present object; the diameter is found to be 6 arcmin, the distance is 15304-60pc from the Sun and the age is 900＋50Myr. The optical reddening E（B - V） = 0.65 mag, while the infrared reddening is E（J - H） = 0.20 mag. The slope of the mass function distribution and the relaxation time estimations indicate that cluster NGC 6724 is dynamically relaxed.展开更多
Evidence-based medicine is an authoritative way of evaluating the clinical efficacy of drugs, which provides the direct evidence for clinical medication. The rise of evidence-based medical research brought about t...Evidence-based medicine is an authoritative way of evaluating the clinical efficacy of drugs, which provides the direct evidence for clinical medication. The rise of evidence-based medical research brought about the changes in Chinese medicine from the empirical medical era into the era of evidence-based medicine. Chinese medicine, as the experience展开更多
China looks to the wisdom of its ancient philosophy to spread the message of harmony When the founder of China’s Taoist philosophy Lao Zi first began to write Daodejing(Classic of the Way and Virtue),he believed the ...China looks to the wisdom of its ancient philosophy to spread the message of harmony When the founder of China’s Taoist philosophy Lao Zi first began to write Daodejing(Classic of the Way and Virtue),he believed the con-cept in his mind was too展开更多
文摘BVRI CCD photometry of the poorly studied open cluster NGC 6724 has been carried out down to a limiting magnitude of V-20 mag. The stars of the cluster have been observed using the Newtonian focus （f/4.84） of the 74-inch telescope at Kottamia Astronomical Observatory in Egypt. Also, the 2MASS - JHK system is used to confirm the results we obtained. The main photometric parameters have been estimated for the present object; the diameter is found to be 6 arcmin, the distance is 15304-60pc from the Sun and the age is 900＋50Myr. The optical reddening E（B - V） = 0.65 mag, while the infrared reddening is E（J - H） = 0.20 mag. The slope of the mass function distribution and the relaxation time estimations indicate that cluster NGC 6724 is dynamically relaxed.
文摘Evidence-based medicine is an authoritative way of evaluating the clinical efficacy of drugs, which provides the direct evidence for clinical medication. The rise of evidence-based medical research brought about the changes in Chinese medicine from the empirical medical era into the era of evidence-based medicine. Chinese medicine, as the experience
文摘China looks to the wisdom of its ancient philosophy to spread the message of harmony When the founder of China’s Taoist philosophy Lao Zi first began to write Daodejing(Classic of the Way and Virtue),he believed the con-cept in his mind was too
