Concrete Erosion in Weak Sulfate Environment

The erosion failure mechanism of concrete is studied systematically based on field investigation and laboratory experiments of concrete samples from more than 30 km concrete lining and 10 hydraulic structures of Shandong Jiaodong water diversion project, in which the concrete failed only 3-6 months after conslruction was completed. With electron microscopy scanning, energy dispersive analysis, XKD （X-ray diffraction） analysis and Raman spectrum analysis of the mineral composition of the failure concrete and precipitates, chemical and physical reactions that occurred in the concrete under engineering environment were investigated. The analysis indicated that the rapid corrosion and dissolution reaction of the concrete in weak sulfate environment is due to sulfate and carbonate corrosion with the catalytic magnesium salt at low temperature. Also, corrosion damage facilitates the sulfate ions and carbonate ions into the concrete, and the expansion of ettringite and TSA （thaumasite sulfate attack） reaction also accelerates the corrosion damage of the concrete.

低浓度阿托品在儿童近视控制中的研究进展

伴随着儿童近视发生率的上升和低龄化趋势,近视已成为亟需解决的全球公共卫生问题。控制近视发生发展的有效措施包括双焦眼镜、多焦眼镜、角膜塑形镜和药物等。近年来,阿托品作为控制近视发展的有效药物得到广泛关注。由于低浓度阿托品可以有效控制近视屈光度和眼轴增长,且畏光、视近模糊等不良反应轻,故低浓度阿托品已成为儿童近视防控的研究重点。现就低浓度阿托品在儿童近视控制中的研究进展进行综述。