【简答题】强化传热的基本途径有三个方面: 1 、 提高传热系数: 应采取有效的提高传热系数的措施, 如必须提高两侧表面传热系数中较小的项。 另外应注意: 在采取增强传热措施的同时, 必须注意清除换热设备运行中产生的污垢热阻, 以免抵消 强化传热带来的效果。 2 、 提高换热面积:采用扩展表面,即使换热设备传热系数及单位体积的传热面积增加,如肋壁、 肋片管、波纹管、板翅式换热面等;当然必须扩展传热系数小的一侧...
【单选题】Why is it often difficult and expensive for marketers to attract new customers?
A.
customers are easily persuaded by promotions
B.
many times customers base buying decision solely on satisfaction with past purchases and do not consider other alternatives
C.
customes routinely ignore promotional attempts
D.
for most products the market is saturated, meaning there is not many new customers to attract
E.
customers tend to be distrustful of new products
【多选题】新闻评论员要具有政治敏锐性以及评论的敏感,就是对()的敏感与把握。
【判断题】Marketers often involve actual customers in product testing.
【单选题】金融市场( ),可分为货币市场和资本市场。
【简答题】Marketers can use ___, ___ and ___ to occupy the target market.
【判断题】述评性新闻带有评论色彩,可以依托新闻事实,也可以不依托新闻事实进行评论。( )