平推流反应器 Piston Flow Reactor (PFR) 活塞流模型或理想置换模型 This type of units is illustrated in the following figure. This reactor consists of a tube inside which the reaction medium flows. This makes i t t h e s i m p l e s t s t r u c t u r e conceivable f or a continuou s o p e r a ti o n s ys t em . Th e h ea t exchange necessary to add heat to the system or to remove it generally occurs ac ros s the tube wall
1 . A reaction has the stoichiometric equationA+B=2R. What is the order of reaction? 2. A reaction with stoichiometric equationhas the following rate expressionWhat is the rate expression for this reaction if thestoichiometric equation is written as A+2B=2R+S?A B R S2
The expectation or expected value of a random variable is a single number that tells you a lot about the behavior of the variable. Roughly, the expectation is the average value, where each value is weighted according to the probability that it comes up. Formally, the expected value of a random variable r defined on a sample space s is: (B)=∑R()Pr(o) To appreciate its signficance, suppose S is the set of students in a class, and we select a student uniformly at random. Let r be the selected student's exam score. Then
处理器无疑是计算机中最重要的部件,但并不是唯一的部件 。一台计算机也需要随机访 问存储器(R A M)来存放机器码指令以便让处理器执行。计算机还必须有一些方法使这些指 令进入R A M(输入设备)以及一些方法使程序执行结果得以看见(输出设备)。前面讲过, R A M是易失性的,当断电时,它的内容就会丢失。所以计算机中另一个有用的部件是永久存 储设备,当计算机断电的时候,它们可以保存代码和数据