小麦粉及其制品中偶氮甲酰胺检测方法研究进展

偶氮甲酰胺(azodicarbonamide,ADA)是小麦粉常用的食品添加剂,具有增白、强筋作用。ADA在湿热环境下不稳定,能够转化为联二脲(biurea,BIU)和氨基脲(semicarbazide,SEM)。SEM是兽药呋喃西林的代谢物,具有较强的致癌、致畸、致突变作用。小麦粉及其制品中ADA检测方法可分为直接检测法和间接检测法,直接检测法以ADA为目标检测物,间接检测法以BIU和SEM为目标检测物。本文综述了小麦粉及其制品中ADA检测方法研究进展,分析了我国现行ADA检测标准存在的问题,展望了ADA分析检测研究的发展趋势,为ADA分析检测研究与实践提供参考。

Effect of Carbonation and Drying-Wetting Cycles on Chloride Diffusion Behavior of Coral Aggregate Seawater Concrete

Based on seawater immersion,drying-wetting cycles,carbonation and drying-wetting cycles for coral aggregate sea-water concrete(CASC)with different strength grades,the effect of carbonation and drying-wetting cycles on chloride diffusion be-havior of CASC is studied.The results show that the free surface chloride concentration(Cs),free chloride diffusion coefficient(Df)and time-dependent index(m)of CASC in the drying-wetting cycles is obviously higher than that in seawater immersion.The Df and m of CASC of carbonation and drying-wetting cycles is higher than that in the drying-wetting cycles.Carbonation increases the Df and m of CASC,which is against CASC to resist chloride corrosion.The corrosion possibility of CASC structures in different ex-posed areas is as follows:splash zone(carbonation and drying-wetting cycles)>tidal zone(drying-wetting cycles)>underwater zone(seawater immersion).Besides,the chloride diffusion rate of C65-CASC is 17.8%-63.4%higher than that of C65-ordinary aggre-gate concrete(OAC)in seawater immersion(underwater zone).Therefore,anti-corrosion measures should be adopted to improve the service life of CASC structure in the oceanic environment.

Effect of carbonation-drying-wetting on durability of coral aggregate seawater concrete

Based on the drying-wetting cycles experiment and the carbonation-drying-wetting cycles experiment for coral aggregate seawater concrete(CASC)with different strength grades,the effects of carbonation-drying-wetting on the durability of CASC are studied with the surface state,mass loss rate,relative dynamic elastic modulus,ultrasonic wave velocity and cube compressive strength as indices.Results show that the mass loss rate of CASC increases gradually with the increase in cycle times in the drying-wetting and carbonation-drying-wetting cycles.The mass loss rate increases relatively slowly at the initial stage but it increases remarkably after 10 cycles.The relative dynamic elastic modulus and ultrasonic wave velocity decrease gradually with the increase in cycle times.After 6 cycles,the decrease rate of the relative dynamic elastic modulus and ultrasonic wave velocity of CASC tends to be flat and the surface is slightly damaged.Compared with the initial 28 d cube compressive strength,the cube compressive strength of CASC decreases by 8.8%to 11.0%.Drying-wetting cycles and carbonation can accelerate seawater erosion on CASC,and drying-wetting cycles result in salting-out and accelerate the destruction of concrete.Therefore,the carbonation-drying-wetting accelerates the destruction of CASC.

PDCA循环法在完善医院感染信息系统中的应用

目的 探讨应用PDCA循环(Plan-Do-Check-Act)法在完善医院感染信息系统各项功能中的作用,为保障系统处于良好的运行状态,促进信息系统监测功能持续改进提供有效管理方法。方法 选取某综合性医院的医院感染预警系统,采用PDCA循环法对院感信息系统感染病例预警、主界面显示、环境卫生学、暴发预警、多重耐药菌、职业暴露、短信通知等模块进行完善,分析2020年8月-2021年12月系统各模块的问题解决情况和新需求实现情况,以及医务人员对于该系统使用的满意程度。结果 总体上96.47%的问题和80.00%的新需求得以解决和实现;51.76%的问题和50.00%的新需求均集中在感染病例预警模块,63.53%的问题和20.00%的新需求在24 h内解决和实现;临床医务人员对感染病例预警模块的满意率(58%)低于对总界面显示模块的满意率(78%),差异具有统计学意义(χ^(2)=9.604,P<0.05)。结论 运用PDCA循环管理方法对医院感染管理信息系统质量的提高具有较好的促进作用,能及时发现系统存在的问题并缩短处理时间,有利于各模块功能的完善。