Glass matrix composite material prepared with waste foundry sand

The technology of glass matrix of the composite material manufactured through a sintering process and using waste foundry sand and waste glass as the main raw materials was studied. The effects of technological factors on the performance of this material were studied. The results showed that this composite material is formed with glass as matrix, core particulate as strengthening material, it has the performance of glass and ceramics, and could be used to substitute for stone.

四川省甘孜州高原藏族地区0~6岁儿童维生素A水平与影响因素

目的考察甘孜藏族自治州0~6岁儿童血清维生素A(VitA)水平,为预防VitA相关疾病的发生提供参考依据。方法2017年4月-2019年4月在甘孜州乡城县和稻城县对2122名藏族儿童进行体格检查,并采用高效液相色谱法检测血清VitA的含量。结果2122名0~6岁儿童血清VitA平均水平为(1.05±0.27)μmol/L,亚临床缺乏率为8.15%,可疑亚临床缺乏率为45.99%。婴儿组VitA平均水平为(0.94±0.26)μmol/L,低于幼儿组[(1.09±0.28)μmol/L]和学龄前儿童组[(1.05±0.27)μmol/L](F=15.308),海拔4 km以上VitA平均水平为(0.96±0.19)μmol/L,低于海拔2~3 km[(0.99±0.26)μmol/L]和3~4 km[(1.12±0.27)μmol/L](F=61.735),夏季VitA平均水平高于其他季节(F=52.194),差异均有统计学意义(P<0.001)。此外0~1岁组亚临床缺乏率为23.97%,高于其他年龄段(χ^(2)=43.503,P<0.001)。Logistic回归分析结果显示海拔高度、季节和年龄对亚临床缺乏和可疑亚临床缺乏均有影响,其中随着海拔升高亚临床缺乏和可疑亚临床缺乏发生几率增大。结论甘孜藏族自治州0~6岁儿童VitA平均水平较低,以可疑亚临床缺乏为主,VitA的缺乏与年龄、海拔、季节相关,不同年龄阶段儿童应根据当地海拔高度、不同季节补充VitA及富含VitA的食物,以预防VitA缺乏及相关疾病的发生。