公差带X-rays were discovered by Wilhelm Rontgen, a German physicist in 1895.To generate x-rays, three things are needed.•a source of electrons •a means of accelerating the electrons at high speeds•a targ
南昌师范学院学报(综合)Journal of Nanchang Normal University! Comprehensive )2020年12月第41卷第6期Dec.2020Vol. 41 No. 6初中数学学业评价与课程标准的一致性研究——以五份省统一命题的数学中考试卷为例孙庆括,潘腾,胡启宙(南昌师范学院数学与计算机科学系,江西南昌33003