下面为CO₂加氢制取乙醇的反应：

2CO₂（g）+6H₂（g）⇌CH₃CH₂OH（g）+3H₂O（g）

△H=QkJ/mol （Q＞0）

在密闭容器中，按CO₂与H₂的物质的量之比为1：3进行投料，在5MPa下测得不同温度下平衡体系中各种物质的体积分数（y%）如图1所示．完成下列填空：

（1）表示CH₃CH₂OH体积分数曲线的是____ （选填序号）．

（2）图1中曲线a和c的交点R对应物质的体积分数 y_R=____ %．

（3）在强酸性的电解质水溶液中，惰性材料做电极，电解CO₂可得到多种燃料，其原理如图2所示．

①该工艺中能量转化方式主要有____ 

②电解时，生成乙烯的电极反应式____ 

（4）在3L容积可变的密闭容器中发生反应，H₂（g）+CO₂（g）⇌H₂O （g）+CO（g）已知c（CO）﹣反应时间t变化曲线Ⅰ如图3所示，若在t₀时刻分别改变一个条件，曲线Ⅰ变为曲线Ⅱ和曲线Ⅲ．当曲线Ⅰ变为曲线Ⅱ时，改变的条件是____ 

当曲线Ⅰ变为曲线Ⅲ时，改变的条件是____ 

                                                                                              America's top comic book stores

    New York City, NY － JHU Comic Books

    NYC has a number of impressive comic book stores. While other comic book stores in the city fill their shelves with other products like cards and board games, JHU focuses only on the comics themselves, with shelves filled with great selections of the latest releases and back issues from wall to wall. (32 East 32nd St, 212 — 268 — 7088)

    Austin, TX－Austin Books & Comics

    Opened in 1977, Austin Books &. Comics is one of Texas' biggest and longest running comic book stores. Not only do they sell the latest issues, they also carry many first editions and back issues. Good news is that they often hold regular book purchase discount activities, which means that you'd better consult them before your visit. (5002 N Lamar Blvd, 512－454－4197)

    Washington D. C. － Big Planet Comics

    This store, originally from Georgetown, prefers the more independent, small-press titles as well as stuff from Europe and Japan that your kids probably haven't even heard of, but they also carry the more popular ones. True to its name, BPC has established its own comic book world, with book signing and meet-and-greet events, and their very own, though tiny, comic book publishing house. (1520 U St NW, 202 —342 —1961)

    Portland 9 OR － Floating World Comics

    Floating World Comics is not only a comic book store but a community hosting art shows. Priding itself on cool style, this is an ideal place for comic books, where art books fill shelves just as much as the more mainstream comics. Both the future artists and the comic book lovers in your family will more than appreciate a stopover during your Portland vacation. (400 NW Couch St, 503－241－0227)