Objective To study secondary wall formation of helical tracheary elements in the stem of Cucurbita moschata.
目的观察南瓜(Cucurbita moschata)茎螺纹导管发育过程中次生壁的形成过程。
small bundles of spiral vessels
螺纹导管的小维管束
pin-to-box pipe
阳螺纹-阳螺纹管子
Tubing thread is available for API tubing threads and TM threads.
油管螺纹可采用API油管螺纹，或TM螺纹。
NPT tapered tube thread gauges
NPT锥管螺纹量规
Conduits for electrical purposes--Outside diameters of conduits for electrical installations and threads of conduits and fittings
GB/T17194-1997电气导管电气安装用导管的外径和导管与配件的螺纹
Apply pipe dope sparingly on pipe threads, never on valve threads.
在管道螺纹上涂敷螺纹油，但是不要在阀门螺纹上涂螺纹油。
Pipe threads where pressure-tight joints are made on the threads
GB/T7306-1987用螺纹密封的管螺纹
minimum number of pipe threads for connections
管螺纹连接的最少螺纹牙数
Pipe threads where pressure-tight joints are not made on the threads
GB/T7307-1987非螺纹密封的管螺纹
A pipe coupling threaded on both ends.
螺纹接头一种两端都带外螺纹的管子
Gauges for sealing tube threads
用螺纹密封的管螺纹量规
Gauges for nonsealing tube threads
非螺纹密封的管螺纹量规
threaded bottom guide
有螺纹的底部导向鞋
internal ribbed tube
内肋片管，内螺纹管
With certain shapes of nozzle or canula, elongated caps are made to cover both canula and threaded portion, and seal the canula at its top.
根据管口和导管的不同形状，可以制造细长的管盖以覆盖导管和螺纹部分，并在顶部封住导管。
Taper pipe threads with 60 degree
GB/T12716-199160°圆锥管螺纹
Forged steel threaded pipe fittings
GB/T14626-1993锻钢制螺纹管件
API tubing thread
美国石油学会油管螺纹