按日期为Twitter搜索结果绘制文字云？ （使用R）

I wish to search twitter for a word (let's say #google), and then be able to generate a tag cloud of the words used in twitts, but according to dates (for example, having a moving window of an hour, that moves by 10 minutes each time, and shows me how different words gotten more often used throughout the day).I wish to search twitter for a word (let's say