气相色谱仪中用TCD为检测器时,其灵敏度与()的关系最大。
A.固定相
B.载气种类
C.TCD池体温度
D.载气流速
参考答案:C
在坡度为( )的坡地整地造林,抚育幼林,垦覆油茶、油桐等经济林木,都必须采取水土保持措施。
A.5°以上
B.15°以上
C.25°以上
D.任何角度
Both bus and tree topologies are characterized by the use of multipoint (71) .For the bus,all stations attach,through appropriate hardware (72) known as a tap,directly to a linear transmission medium,or bus.Full-duplex operation between the station and the tap allows data to be transmitted onto the bus and received from the (73) .A transmission from any station propagates the length of the medium in both directions and can be received by all other (74) .At each end of the bus is a (75) ,which absorbs any signal,removing it from the bus.
A.medium B.connection C.token D.resource