X线机的高压整流方式不包括() A.单相全波整流 B.单相半波整流 C.自整流 D. 发布时间:2018-01-27 02:19 │ 来源:www.tikuol.com 题型:单项选择题 问题: X线机的高压整流方式不包括()A.单相全波整流B.单相半波整流C.自整流D.三相4波整流E.三相12波整流
题型:单项选择题 In low-speed network,it is usually adequate to wait for congestion to occur and then react to it bytelling the source of packets to slow down.In high-speed networks,this approach often works poorly,because in the (71) between sending the notification and notification arriving at the source,thousands of additional (72) may arrive.In ATM network,a major tool for preventing (73) is (74) control.When a host wants a new virtual (75) ,it must describe the traffic to be offeredand the service expected.(72)处填()。A.packetsB.cellsC.messageD.files 查看答案
题型:单项选择题 2009年1—4月我国完成城镇固定资产投资为37082.30亿元,比去年同期增长30.5%,其中第一产业比去年同期增长82.1%,投资比重见下图。 2009年1—4月我国完成城镇固定资产投资中第三产业多少亿元()A.20506.51B.21451.68C.23456.64D.24536.52 查看答案