不同冷冻介质与EPS泡沫箱在模拟冷藏运输中的效果研究

为探究冷冻介质和EPS泡沫箱在模拟冷藏运输中保温效果,分别研究了不同环境温度下,EPS泡沫箱的保温时长变化规律,EPS泡沫箱的厚度和内表面积对保温效果的影响,6种蓄冷介质在EPS泡沫箱中的保温效果。结果表明,在10~35℃的环境温度范围内,EPS泡沫箱的保温时长(Y)与外界温度(X)呈显著负相关,符合拟合方程:Y=73.788e-0.299X(R^2=0.9973)。EPS箱的保温时长与内表面积和厚度符合傅立叶方程式,但是保温时长与二者并不成简单的线性关系。根据保温性能综合比较,保鲜冰袋保温效果最优,其次为水冰瓶和注水冰袋;根据释冷特征,推荐保鲜冰袋与注水冰袋联合使用。研究为各种食品、药品、鲜活水产品在特定情况下运用泡沫箱保活、保鲜运输提供科学依据与实践指导。

浓缩乳酸菌发酵剂冷冻干燥介质的选择

试验采用冷冻乳酸菌悬浮液的方法选择出理想的冷冻介质，其组成为：脱脂乳、蔗糖、麦芽糖、蛋白胨、酵母浸出物、Ｖｃ、甘油和谷氨酸钠。保加利亚乳杆菌和嗜热链球菌分别悬浮在该介质中进行冷冻干燥（４Ｐａ，－３５℃，２８ｈ），其冷冻干燥存活率分别是７０．４％和８９．７％，明显抑制了冷冻干燥过程对乳酸菌造成的损伤作用。

Analyses of concrete microcosmic structure in multi-media environment

The structure of concrete generally serves in multi-media environments; various environments act differently on concrete. The compound action of some severe environments will threaten the duration of concrete and decrease the service life of a concrete structure if improperly handled. In this paper the microstructure of concrete is observed by using Scanned Electric Microscope (SEM) through contrasting experiments in media of acid, alkali and salt with that of freezing-thawing in the same medium environment. This study is to supply a certain basis for changing traditional thinking of mechanical design and to combine construction reliability design with durability of concrete design.