高压导线的分类有哪几种？
参考答案：高压导线可分为普通铜芯导线和高压阻尼线两种。高压阻尼线的特点是：可抑制和衰减点火系统所产生的对无线电设备干扰的电磁波。
下列指标中，能较好反映物流管理物化劳动和活劳动消耗的是()。
A.物流商品总量
B.劳动生产率
C.单位物流成本
D.仓容利用率
(66) is a one-way function that takes an arbitrarily long piece of plaintext and from it computes a fixed-length bit string. (67) is a protocol that most USENET machines how use it to allow news articles to propagate from one machine to another over a reliable connection. (68) is an approach preferred by cable TV providers. In this solution the fiber terminates at an optoelectrical converter and the final segment is a shared coaxial cable. (69) is a device used to connect two separate network that use different communication protocol. (70) js a digital-to-digital polar encoding method in which the signal level is always either positive or negative.
A．MD
B．RSA
C．DES
D．MIB
