【判断题】《床的左边是海,床的右边是山》中,两只海龟做吊床的目的是想霸占小熊的床。
【判断题】16判断Annealing and normalizing present a significant difference on the ductility of low carbon steels.
【单选题】对化学防腐剂抑菌范围的说法正确的是
A.
丙酸盐主要针对酵母菌和霉菌,细菌只能部分被抑制
B.
苯甲酸对酵母菌和霉菌,细菌都有作用,但对嗜酸乳杆菌几乎无效
C.
山梨酸主要作用于霉菌,对细菌作用有限,对酵母菌无作用
【简答题】Annealing and normalizing is often used to achieve dispersion strengthening. Annealing is a heat treatment used to produce a soft, coarse pearlite in steel by austenitizing, then furnace cooling. Norm...
【判断题】Annealing and normalizing present a significant difference on the ductility of low carbon steels.
【简答题】What is the annealing heat treatment for steel and what are its purposes?
【多选题】(第三章)关于羟苯酯类防腐剂,说法正确的是:
A.
化学性质稳定,在pH 3-8范围内能耐100℃ 2小时灭菌。
B.
在酸性、中性溶液中均有效,但在酸性溶液中抑菌作用较强,其中对金黄色葡萄球菌作用最强。在弱碱性溶液中由于酚羟基解离,致使其抑菌作用减弱。
C.
抑菌作用随烷基碳数的增加而增强,而溶解度则随碳数的增加而下降。
【简答题】The process annealing used to and increase the ductility of a previously strain-hardened metal.