【简答题】请仔细阅读以下转化关系 已知: (Ⅰ) 烃类化合物A的质谱图表明其相对分子质量为84;红外光谱表明其分子中含有碳碳双键;核磁共振氢谱显示其分子中只有一种氢原子。 (Ⅱ) D1、D2互为同分异构体,E1、E2互为同分异构体。 (Ⅲ)共轭二烯烃1,2加成:CH 2 =CH-CH=CH 2 +Br 2 CH 2 Br-CHBr-CH=CH 2 共轭二烯烃1,4加成:CH 2 =CH-CH=CH 2 +B...
【判断题】Huffman coding is a lossy compression method.
【单选题】Mr. Smith, Mr. White ______ from Chicago just now and here's the message for you.
【简答题】(18分) 根据以下有机物之间的转化关系框图,回答问题: (1)已知:B、C的分子结构中均带有支链,B的结构简式为__________,C在浓硫酸加热条件下只能得到一种结构的烯烃D,C的结构简式可能为___________或___________,D的高名称为(用系统命名法命名)_________________。 (2)F中含有的官能团的名称为____________________。 (3)③...
【简答题】ADPCM is a _______ (lossy/lossless) compression method.
【判断题】Using a lossy compression method, the original image cannot be fully restored.
【单选题】在OSI模型中,第N层和其上的第N+1层的关系是 。
【单选题】扑灭精密仪器等火灾时,一般用的灭火器为( )
【单选题】听力原文:M: May I speak to Mr. Smith, please? W: There are two Smiths here. Which one do you want? M: Tim Smith, please. W: Nobody by that name here. M: Is your number 1132445. W: Sorry, here is 1132455. ...
A.
Tim Smith isn't in right now.
B.
The caller dialed the wrong number.
C.
Tim Smith is busy now.
【简答题】Compression techniques have two categories: ( ) and lossy