有两种格式的代码使用同一管类型代码，其中使用的是从1948年类型，直到这些公司停止接收管的标准制造。

There were two types of code formats that used the same tube type codes, which were in use from 1948 until these companies stopped the manufacture of standard receiving tubes.

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文中给出了流函数方程及边界条件的坐标转换形式和离散格式，采用了强隐式(SIP)迭代法，分别对具有弓形和半弓形突体的直管进行了计算。

In this paper, the transformed forms of the flow function equation and boundary conditions and their difference expressions are given, and Strongly Implicit Procedure (SIP) iteration is used.

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