【简答题】并联式稳压电路如下图所示。已知稳压管的稳定电压为6V,允许电流范围5~40mA,当R L =1kΩ,I L =______;R L 开路时,稳压管的最大耗散功率为______。
【单选题】1995年世界上第一个网上银行---安全第一网络银行在()建立的。
【单选题】女性,36岁,因全口多数牙齿松动1年余就诊,接诊时需询问是否患有全身疾病,有关全身疾病与牙周炎,叙述不正确的是()
A.
牙周感染可能是心血管疾病、呼吸道感染等的危险因素
B.
分娩低出生体重儿的妇女的龈下菌斑中有比正常产妇更多的牙周致病菌
D.
糖尿病患者中牙周炎的发生率和严重程度均高于非糖尿病人群
E.
彻底有效的牙周治疗可使糖尿病患者的糖化血红素显著降低
【单选题】2 Who has the lowest risk of death?
A.
people who don’t experience a lot of stress but who believe that stress is dangerous
B.
people who experience a lot of stress but who think that stress isn’t harmful
【多选题】公路缓和曲线在使用过程中要求( )。
C.
缓和曲线的参数A尽量满足在1/3R-R之间。
【单选题】Who has the lowest risk of death?
A.
people who don't experience a lot of stress but who believe that stress is dangerous
B.
people who experience a lot of stress but who think that stress isn't harmful