聚乙烯补伤片基材厚度为()。
A.当管径≤400mm时基材厚度≥1.2mm
B.当管径≤400mm时基材厚度≥1.0mm
C.当管径>400mm时基材厚度≥1.5mm
D.当管径>400mm时基材厚度≥2.0mm
A.当管径≤400mm时基材厚度≥1.2mm
B.当管径≤400mm时基材厚度≥1.0mm
C.当管径>400mm时基材厚度≥1.5mm
D.当管径>400mm时基材厚度≥2.0mm
女性,21岁,题中60kg。烧伤面积40%,伤后第一个24小时的补液总量为
A 4400ml B 5000ml C 5600ml D 6200ml E 6800ml
根据气力输送的特点,降低动力消耗,节约能源是一个重要的研究课题,从经验中知,管道内径是关于能耗的重要参数。直观上看,当输送量一定时,管径过小,输送易阻滞,管径过大,虽输送畅通,但又造成能量的浪费。根据经验,把管径分成三组,各组的试验结果如下表所示,试用方差分析法比较各组的效果.
管径(mm) | 单位功耗 |
230 | 0.0308,0.0476,0.0504 |
250~260 | 0.0532,0.032,0.0218,0.028,0.028, 0.042,0.0336,0.042,0.042,0.028 |
280~320 | 0.07,0.07,0.0644,0.0312,0.0756,0.0756, 0.07,0.0588,0.0588,0.042,0.0308,0.0364, 0.0448,0.21,0.154,0.1064,0.1288,0.112, 0.1064,0.1288,0.0756,0.0644,0.0504,0.0644, 0.0504,0.0308 |
女性,21岁,体重60 kg。烧伤面积40%,伤后第一个24小时的补液总量为
A.4 400 mL
B.5 000 mL
C.5 600 mL
D.6 200 mL
E.6 800 mL
AT切割的石英晶体的等效参数可以用下列各式近似地确定:
式中,d为晶体片厚度,单位为mm;S为面积,单位为mm2;B为晶体的阻尼系数(B≥0.25)。 1)试求d=0.4 mm,S=200 mm2的AT切割的石英晶体的参数; 2)求fq=15 MHz的AT切割石英晶体片的厚度d。
已知磨损系数a=14×10-9mm·s3/(g·h),飞灰浓度不均匀系数ku=1.0,烟气速度场不均匀系数kw=1.0,管束计算断面出的烟气飞灰浓度u(g/m3)管束间最窄处烟气流速ω=11.5m/s。运行时间τ=28000h,锅炉额定负荷时烟气流速与平均运行负荷时的烟气流速之比kD=1.15,碳钢管的抗磨系数M=1.0,灰粒碰撞管壁的频率因子η=0.15。横向节距s1=142mm,管径d=51mm。灰粒碰撞管壁的频率因子η=0.15,计算燃烧烟煤的锅炉省煤器管壁的最大磨损厚度并对计算结果进行分析与讨论。
A.3.38 L/s,de110
B.4.38 L/s,de110
C.3.38 L/s,de125
D.4.38 L/s,de125