镀锌层硅酸盐+虫胶复合转化膜的制备和表征

目的阻碍热镀锌板出现白锈,提高镀锌层的耐腐蚀性能。方法采用正交试验法优化出添加虫胶水溶液的有机无机复合钝化液。通过电化学Tafel极化曲线、交流阻抗(EIS)、乙酸铅点滴和中性盐雾试验,对比分析基体、硅酸盐+虫胶复合钝化膜与铬酸盐钝化膜的耐腐蚀性能。采用摩擦法测试对比分析基体和无铬钝化膜试样的附着性能,并通过扫描电子显微镜、X射线光电子能谱和红外光谱对形貌和结构进行分析。结果添加虫胶水溶液的复合钝化膜表面平整致密,72 h中性盐雾试验后的腐蚀面积小于10%。乙酸铅点滴试验和电化学测试显示,复合钝化膜的耐腐蚀性能较基体好。附着力试验测试显示,复合钝化膜具有良好的附着能力。结论因为复合钝化液中的虫胶与硅酸盐交织为O—Si—CH_2结构,与金属离子结合生成致密的膜层附着在镀锌层表面,使得复合钝化膜致密平整,且使腐蚀过程得到了强烈的抑制。     

广东小作坊生产花生油中黄曲霉毒素B1膳食暴露及风险评估

对广东居民通过小作坊花生油对黄曲霉毒素B_1的膳食暴露及其产生的健康风险进行评价。采用点评估模型对广东不同年龄人群通过花生油对黄曲霉毒素B_1的膳食暴露情况进行评估,按照联合国粮农组织和世界卫生组织食品添加剂联合专家委员会推荐的方法对黄曲霉毒素B_1引发的肝癌风险进行评价。结果表明:2017年广东地区小作坊花生油黄曲霉毒素B_1超标率11. 8%,检出率56. 9%;各年龄组高消费水平暴露量规律为7～14岁 15～50岁 50岁以上 2～6岁,15～50岁、50岁以上、2～6岁3个年龄段女性高消费水平暴露量大于男性;高消费人群由于花生油中黄曲霉毒素B1的膳食暴露引发肝癌的风险为7～14岁男性少年儿童危险度最大,高消费水平肝癌贡献率最高,达28. 9%。高消费人群花生油中黄曲霉毒素B_1引发肝癌的风险相对较高,应对全省小作坊花生油黄曲霉毒素污染予以足够的重视。     

一水硬铝石矿—氢氧化钠体系加热过程中的相变规律

研究了焙烧温度和氢氧化钠添加量对一水硬铝石矿—氢氧化钠体系相变规律的影响。利用DTA-TG、XRD和SEM技术对焙烧产物的加热性能、物相转变和微观形貌进行了分析。结果表明,当焙烧温度较低、氢氧化钠添加量较少时,大量AlOOH没有转变,主要反应是高岭石和白云母与氢氧化钠反应生成沸石、方钠石、霞石等不同物相。温度升高利于沸石和方钠石换成钙霞石。氢氧化钠添加量增多利于AlOOH与NaOH反应生成铝酸钠物相。当温度升高到500℃以上时,主要反应是AlOOH脱水形成Al2O3。     

Gastroparesis: review of the aspects related to its concept, etiopathogeny and clinical handling]

BACKGROUND: Percutaneous closed needle biopsy of musculoskeletal neoplasms has gained in popularity. However, it remains controversial whether or not to resect the needle tract for fear of a local recurrence. A single published case report exists, noting the lone tract recurrence of an extremity skeletal osteosarcoma. METHODS: We report on three additional individuals who demonstrated that tract local recurrences may occur after a closed needle biopsy for nonosteosarcoma, nonextremity sarcomas. For perspective, the world literature is reviewed to identify tract recurrences for other malignancies and the results of needle biopsy in musculoskeletal neoplasms. RESULTS: Eighty-nine percent of needle tract local recurrences occur when carcinomas are subjected to biopsy, as reported in the literature. Forty-seven cases since 1950 are described representing essentially all tumor types. The nature of musculoskeletal neoplasms makes closed biopsy more difficult than for softer, more homogeneous, and easier to access neoplasms. CONCLUSIONS: Local recurrences of sarcoma may occur in closed needle biopsy tracts. Strong consideration should be given to open biopsy and tract resection.     

伯胺N_(1923)从硫酸溶液中萃取Sc(Ⅲ)的机理

本文研究了伯胺N_(1923)的正辛烷溶液从硫酸介质中萃取Sc(Ⅲ)的平衡规律。通过IR,NMR测定及斜率法、等摩尔系列法研究了N_(1923)萃取Sc(Ⅲ)的机理。测定并计算了萃取反应的浓度平衡常数和热力学函数。