If zinc phosphate cement is contaminated by moisture during setting()
A. its solubility increases
B. its hardness increases
C. its pH increases
D. its fluoride release increases
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The following is a description of a glass-ionomer cement’s fluoride release pattern()
A. initial low-rate release,foilowed by long,low-rate release
B. initial high-rate release,followed by long,low-rate release
C. high.rate release throughout the GIC’s lifetime
D. polycarboxylate cement
可锻铸铁中的团絮状石墨由下述方式获得 ()
A. 由白口铸铁经高温退火从渗碳体分解而得到
B. 直接从液体中结晶而得
C. 由灰口铸铁经锻造而得
D. 上述说法都不对
铸造用硅砂含()越高,其耐火度越高。
A. Si02
B. MgO
C. Al2O3
D. Fe2O3
铸造用硅砂的分级依据是()。
A. 二氧化硅含量
B. 含泥量
C. 粒度分布
D. 颗粒形状