Objective: To investigate the situation of quality control of 3.0T magnetic resonance imaging (MRI) system. Methods: A series of indicators, including signal noise ratio(SNR), image uniformity, resolution of long-scale contrast, resolution of space, linearity and quality control of slice thickness, of 3.0T MRI system were measured by using Magphan SMR170 phantom (made by the phantom laboratory in American) on the Discovery MR 750 w system which made by GE company of American. And a series of formula, including SNR=(Sinside-Soutside)÷SDinside, U∑=(1-Smax-Smin/Smax+Smin ×100%, linearity=LR-LM/LR×100%、thickness=half of height and width ×0.25, were used to calculate SNR, image uniformity, linearity and quality control of slice thickness, and all of these results were used to evaluate the situation of quality control of 3.0T MRI system. Results:The results revealed that SNR of 3.0T MRI was 105, the imaging uniformity achieved to 99.13%, the resolution of long-scale contrast was 5mm/0.5mm, the resolution of space was 6 LP/cm, linearity achieved to 0.89% and the deviation of slice thickness was 0.6mm. All of these indicators has achieved the standards of detection. Conclusion: Through detecting the SNR, imaging uniformity, resolution, linearity and the deviation of slice thickness of 3.0T MRI system, the performance of the MRI can be accurately obtained, and these contribute to ensure the equipment operating in ideal situation.

OBJECTIVE:To investigate the effects of different drying methods on contents of active ingredients in leaves of Eu-commia ulmoides,and provide reference for establishing its drying methods after habitat harvesting. METHODS:Different drying methods [natural drying in the shade for 72 h,natural drying in the sunlight for 36 h,drying beside or over a fire(60℃6 h,80℃2 h,100℃1 h,120 ℃ 0.5 h),microwave vacuum freeze drying for 12 h,vacuum freeze drying for 12 h] were used for process-ing. HPLC was conducted to determine the contents of aucubin,geniposidic acid,chlorogenic acid and geniposide in samples and compare with the untreated fresh products. RESULTS:Contents of 4 ingredients in samples after the 2 freeze drying were close to these in fresh samples,which were higher than samples after other drying. CONCLUSIONS:Drying methods show significant ef-fects on the effective ingredients in leaves of E. ulmoides. Compared with natural drying in the shade and natural drying sunlight and drying beside or over a fire,microwave vacuum freeze drying and vacuum freeze drying can make better retention of the active ingredients in fresh leaves of E. ulmoides.