英文文献翻译（附原文）
姓名：李丛荟
班级：机082
学号：2105110812032
导师：赫亮
日期：2012年03月13号
第6章指令表、顺序结构图和结构文本的程序设计方法本章继续接着上一章讨论另外几种标准编程语言，例如，指令表（IL）、顺序结构图（SFC）和结构文本（ST）。
6.1指令表
指令表是一种采用文本形式进行梯形图程序设计的编程方法。指令表的程序由一系列的指令组成，每条指令占一行。程序指令由操作码及的一个至多个操作数组成，执行对象是操作码。梯形图中操作码被看作梯形图的构元素。每条指令都可以使用或更改存在记忆寄存器中的信息。为此，使用了助记符代码，每个代码对应一个操作码梯形图元素。尽管标准IEC 1131-3已经被提出并广泛使用，但是不同制造商使用的指令一定程度上并不一样。表6.1给出一些厂家所使用的指令，及本章所提议的标准指令（后面章节将讲述指令的其他功能。）下面给出使用IEC 113-1标准操作码的例子：
LD A(*加载A*)
AND B (*与B*)
ST Q (*存储结果Q,输出Q*)
在程序的第一行，LD是操作码，A是操作数，在程序末尾括号中*之间的内容是评论，解释这行指令的作用，它是PLC指令的一部分。LD A这条指令表示将A加载至寄存器中，在之后的操作中可以调用它。第二行是A与B的布尔运算中的与操作。最后一行是将结果存储在Q中，即向Q输出。
标号可以用来标识不同的进入程序的入口，在程序跳转时十分有用。标号在指令的前面被冒号分隔开。因此有：
PUMP_OK : LD C (*加载C*)
在程序之前面有一条指令，如果某个特殊的条件满足，那么程序就跳转执行PUMP_OK。
采用IEC 113-1 标准的操作码，在值后面加上字符N表示取反。例如：LD A （*加载A*）
ANDN B （*AND NOT B*）
其中，ANDN操作把梯形图触点先“与”后“取反”。
6.1.1梯形图程序设计及指令表
下面看看梯形图的条件，当一个梯级开始工作，必须要使用一个“开始梯级
代码' 它可以是LD 或L，用于指示梯级以常开触点开始。或者是LDI、LDN、LD NOT、AN或LN,用来指示梯级以常闭触点开始。所有梯级必须以一个输出或存储结果的编码结束。它可以是OUT、=或ST。下图描述了一个梯形图中各独立梯级是如何输入的，其中与门使用三菱的记忆，如图6.1a所示。
此梯形图以操作码LD开始，因为它开始于常开触点。由于输入地址是X400，所以加载指令为LDX400，其后还有一个常开触点作为输入，所以下一行程序指令用AND指令对元件地址逻辑与操作，相应语句为：AND X401。因为，这个梯级要以输出终止，所以用输出指令OUT产生输出，即OUT Y430。因此，梯形图的单个梯级可以用程序指令描述为：
LD X400
AND X401
OUT Y430
同样的功能，采用西门子符号，如图6.1b所示。
A I0.1
A I0.2
= Q2.0
再看另一个与门的例子，如图6.2a所示，采用的是三菱的符号。
梯形图以常开触点开始，指令为LD X400，与X401并联，因此下一条指令为OR X401。最后一条是输出，所以输出为OUT Y430。指令表如下：
LD X400
OR X401
OUT Y430
如图6.2B所示的是西门子符号的或门，指令表如下：
A I0.1
O I0.2
= Q2.0
图6.3a给出了采用三菱符号的非门梯形图系统。
这个梯形图开始于一个常闭触点，所以指令为LDI。在三菱的指令后面加上字母I用来表示对这条指令的取反。紧接着串联一个常闭触点，其指令为ANI，I再次表示对这条与指令的取反，当然I也是一个非门的指令。所梯形图中或非
门的指令可以写成：
LDI X400
ANI X401
OUT Y430
图6.3b是西门子的或非门符号。注意指令后面的字母N的作用是取反。指令表如下：
LN I0.1
AN I0.2
= Q2.0
图6.4a为三菱符号表示的与非门。
梯形图以常触点X400开始，指令语句为LDI X400。下一条对应于一个并联的常闭触点，其指令为OR1 X401。最后一步是输出，指令为OUT Y430。因此，指令表如下：
LDI X400
ORI X401
OUT Y430
图6.4b为采用西门子符号的异或门。指令表如下：
AN I0.1
ON I0.2
= Y430
6.1.2分支代码
如图6.5a所示的采用三菱符号的异或门，它有两条并联的分支，每条分支分别由与关系构成
图中三菱公司使用ORB指令来表示或和并联分支的关系。第一条指令对应一个常开触点X400。下一条指令对应与之串联的常闭触点X401，指令为ANI X401。在读取前两条指令之后，第三条指令开始于新的一行。另起一行是因为它开始于指令LDI，所有新的一行指令语句都是以LD或LDI开始。但是第一行不能以输出结束，所以PLC把与其并联的那行包含在第二行，这样读取以上所列内容直到ORB指令。助记码ORB（分支或模块间的或运算）用于将前两行及第三、四行的指令执行结果进行逻辑或运算。指令表以输出OUT Y430终止。指令表如下：
ANI X401
LDI X400
AND X401
ORB
OUT Y430
图6.5b是西门子的异或门。括弧用来表示将特殊指令结合在一起作为一个区块执行。这种用法和数学方程中的括弧用法相同。例如，（2+3)/4表示2和3相加的结果再除以4。因此，西门子指令表中从第0步的指令A开始，括弧到第三步结束，表示第0步的A只能允许在第一步和第二步指令执行结束后才能够执行。
IEC 1131-3标准应用于此段程序就是使用上述西门子例子中的括弧来实现的。
图6.6a的电路图，采用三菱符号，可看成是两个分支模进行与操作。所采用的指令是ANB。指令表如下：
图6.6b是用西门子符号来表示的同一个电路。本程序中的指令表使用了括弧。第0步的指令A应用到第1、2步的结果中。第4步中的指令A应用到第5、6步的结果中。所以程序的指令表如下：
6.1.3多个梯级
图6.7a是用三菱符号表示的梯形图，它有两层梯级。在编写指令表时，按顺序写出每行的指令。指令LD或LDI表示PLC新的一层梯级开始。指令表如下：LD X400
OUT Y430
LDI X400
OUT Y431
此系统表明，当X400没有被触发时，Y431有输出，Y430没有输出。当X400被触发时，Y430有输出，Y431没有输出。
图6.7b用西门子符号描述了同样的程序。=指令表示一行结束。A或AN指令可以表示一层梯级的开始。但不是必需的，因为还可以用AND和AND NOT表示该指令。则指令表如下：
= Q2.0
AN I0.0
= Q2.1
6.1.4程序举例
下面介绍本节所述程序设计方法的具体应用，以5.7节的梯形图和功能块为例。对照 5.7节中梯形图的解释，在此只讲述和程序相关的指令表。
如果水泵在运行状态，且满足一定压力条件或指示灯开关闭合，那么信号灯亮。图6.8给出了梯形图和相关的指令表。
对于一个用来提升负载的阀，当泵在运行并且提升开关闭合或有开关指示负载在底部提升槽中而没有被提升，那么阀工作。图6.9是其梯形图及与之对应的指令表
当四个传感器中的任意一个有输出时，系统都没有输出产生，否则有输出产生，图6.10给出了梯形图程序及与之对应的指令表。
6.2 顺序功能图
如果想描述一个交通灯序列。一种方法就是把它看成是一系列的功能或状态，例如红灯状态、绿灯状态，然后考虑每个状态的输人和输出。
如图6.11就是对此的描述。状态0的输人在绿灯持续亮一分钟后触发，然后以红灯亮作为输出。状态I的输人在红灯持续亮一分钟后触发，然后以绿灯亮作为输出。
顺序功能图是一种系统操作的图形表示，它描述了一系列操作中的事件顺序。顺序功能图遵循以下规则：
1.这种操作用互相独立、相继连接的状态或动作来描述，用矩形方框来表示状态，每个方框代表被控系统的某个状态。程序的初始化动作与其他动作的表示方法有所不同。图 6.12给出了它的表示法。
2.在两个状态之间的连接线上有一条水平的短线，表示系统从一个状态到下一个状态需要满足的转换条件。两个动作之间不能直接连接，它们中间必须加转换条件。两个转换条件之间也不能直连，中间必须有动作状态。
3.下一状态的转换条件满足时，程序中的下一个状态或动作就开始执行。
4.从一个状态到下一个状态的程序进程将会持续执行直到一个完整的机器
周期结束。
5.任一状态的输出/动作都由水平连接的方框表示，当状态转换条件满足时，产生输出。
图6.13描述了部分顺序功能图及其等价的梯形图。
为了说明顺序功能图的规则，以家庭洗衣机的部分洗漆周期为例。洗衣机滚桶内注满水后便打开加热器开关，直到温度达到要求的标准，然后滚桶转动一段特定时间。用一系列顺序状态表示，如图6.14所示
6.2.1分支和汇聚
如图6.15所示，当跳转条件满足时，选择性分支便转移至相应的状态。
并联分支如图6.16所示，由一对平行线表示，可同时执行两个或多个不同的状态。
图6.17和图6.18给出了顺序功能图中汇聚的表示方法。在图6.17中，若IN4发生，执行顺序从状态2转移到状态4，或若IN5发生，可从状态3转移到状态4。在图6.18中，若IN4发生，执行顺序可同时从状态2、3转移到状态4 6.2.2动作
对于某个状态来说，可以执行一个或多个动作。所谓“动作”就像上面例子中的输出，用方框表示。
动作的行为可以用梯形图、功能块、指令表和结构文本来描述。所以，当使用梯形图时，动作的行为由方框中的梯形图表示。当有电流输人“动作框图”中时，方框所表示的动作就会被激活。如图6.20所示。
在动作框图前通常附一个限定符，用以说明动作执行的条件。若没有限定符或限定符在相关状态激活时，所要求动作就不能被存储及连续执行。限定符P 用于脉冲动作，当某一程序步骤激活时它只执行一次。限定符D用于延时动作，在一段时间之后相应动作才会激发。限定符L用于限时动作，在执行一段时间以后才停止相应动作，如图6.21所示。
6.3结构文本
结构文本是一种和PASCAL极其相似的编程语言。程序由一系列被分号隔开的陈述语句构成。这些语句使用预先定义的语句和子函数来改变变量，变量可以是已定义的值或内部存储值或输入/输出值。
赋值语句用于对欲改变的变量进行赋值。例如：
Light:=SwitchA；
表示变量Light的值将被改变，当开关A闭合或断开时，变量Light的值也随之变化。赋值语句的一般格式如下：X:=Y ;
其中，X是自变量，Y是因变量。再看另一个例子：
Light:—SwitchA OR SwitchB；
表示灯的开关由开关A或B控制。
表6.2给出了一些结构文本中的操作符，
如上面语句中的OR。并且也列出了它们在程序运行时的优先级。例如，
InputA=6
InputB=4
InputC=2
OutputQ:=InputA/3+InputB/(3-InputC)
其中，(3-InputC)的值作为函数的除数，所以计算输出Q语句的第二步是
4/(3-2)=4。除法比加法优先，所以第一步在计算加法之前计算6/3。因此，输出OutputQ的值是2+1=3。
结构文本对字符大小写不敏感，因此为了增强可读性可任意使用大小写字母。同样，也可使用空格键或空行来增强可读性。所有表示变量的等式都以字符%开始，在其后面是一个或两个字母码用以标识其存储单元和其相应数据类型，其中存储单元包括输入/输出存储器或内部存储器，数据类型包括位、字节、字。例如：
%IX100(*Input memory bit 100*)
%ID200(*Input memory word200*)
%QX100(*Output memory bit 100*)
第一个字母I是输入存储单元，Q是输出存储单元，M是内部存储器。第二个字母X表示位，8表示字节I(8位)，W表示字(16位)，D表示双字(32位)，L 表示长字(64位)。
AT用来确定变量的存储单元。因此有：
Input AT %IX100; (*Input is located at input memory bit 100*)
6 IL, SFC and ST programming methods
This chapter continues from the previous chapter and discusses the other IEC 1131-3 (International Electrotechnical Commission) programming languages, i.e. instruction lists (IL), sequential function charts (SFC), and structured text (ST).
6.1 Instruction lists
A programming method, which can be considered to be the entering of a ladder program using text, is instruction lists (IL). Instruction list gives programs which consist of a series of instructions, each instruction being on a new line. An instruction consists of an operator followed by one of more operands, i.e. the subjects of the operator. In terms of ladder diagrams an operator may be regarded as a ladder element. Each instruction may either use or change the value stored in a memory register. For this, mnemonic codes are used, each code corresponding to an operator/ladder element. The codes used differ to some extent from manufacturer to manufacturer, though a standard IEC 1131-3 has been proposed and is being widely adopted. Table 6.1 shows some of the codes used by manufacturers, and the proposed standard, for instructions used in this chapter (see later chapters for codes for other functions).
Table 6.1 Instruction code mnemonics
Store result register An output into operand
LD A (*Load A*)
AND B (*AND B*)
ST Q (* Store result in Q, i.e. output to Q*)
In the first line of the program, LD is the operator, A the operand, and the words at the ends of program lines and in brackets and preceded and followed by * are comments added to explain what the operation is and are not part of the program operation instructions to the PLC. LD A is thus the instruction to load the A into the memory register. It can then later be called on for further operations. The next line of the program
has the Boolean operation AND performed with A and B. The last line has the result stored in Q, i.e. outputted to Q.
Labels can be used to identify various entry points to a program, useful as we will find later for jumps in programs, and these precede the instruction and are separated from it by a colon. Thus we might have: PUMP_OK: LD C (* Load C*)
with there being the instruction earlier in the program to jump to PUMP_OK if a particular condition is realised.
With the IEC 113-1 operators, an N after it is used to negate its value. For example, if we have:
LD A (*Load A*)
ANDN B (*AND NOT B*)
Thus the ANDN operator inverts the value of ladder contacts and ANDs the result.
6.1.1 Ladder programs and instruction lists
When looked at in terms of ladder diagrams, whenever a rung is started, it must use a ‘start a rung code’. This might be LD, or perhaps A or L, to indicate the rung is starting with open contacts, or LDI, or perhaps LDN or LD NOT or AN or LN, to indicate it is starting with closed contacts. All rungs must end with an output or store result code. This might be OUT or = or ST. The following shows how individual rungs on a ladder are entered using the Mitsubishi mnemonics for the AND gate, shown in Figure 6.1(a).
The rung start with LD because it is starting with open contacts. Since the address of the input is X400, the instruction is LD X400. This is followed by another open contacts input and so the next program line involves the instruction AND with the address of the element, thus the instruction is AND X401. The rung terminates with an output and so the instruction OUT is used with the address of the output, i.e. OUT Y430. The single rung of a ladder would thus be entered as:
LD X400
AND X401
OUT Y430
For the same rung with Siemens notation (Figure 6.1(b)) we have:
A I0.1
A I0.2
= Q2.0
Consider another example, an OR gate. Figure 6.2(a) shows the gate with Mitsubishi notation.
The instructions for the rung start with an open contact is LD X400. The next item is the parallel OR set of contacts X401. Thus the next instruction is OR X401. The last step is the output, hence OUT Y430. The instruction list would thus be:
LD X400
OR X401
OUT Y430
Figure 6.2(b) shows the Siemens version of the OR gate. The following is the Siemens instruction list:
A I0.1
O I0.2
= Q2.0
Figure 6.3(a) shows the ladder system for a NOR gate in Mitsubishi notation. The rung starts with normally closed contacts and so the instruction is LDI. I when added to Mitsubishi instruction is used to indicate the inverse of the instruction. The next step is a series normally closed contact and so ANI, again the I being used to make an AND instruction the inverse. I is also the instruction for a NOT gate. The instructions for the NOR gate rung of the ladder would thus be entered as: LDI X400
ANI X401
OUT Y430
Figure 6.3(b) shows the NOR gate with Siemens notation. Note that N added to an instruction is used to make the inverse. The instruction list then becomes:
LN I0.1
AN I0.2
= Q2.0
Consider the rung shown in Figure 6.4(a) in Mitsubishi notation, a NAND gate.
It starts with the normally closed contacts X400 and so starts with the instruction LDI X400. The next instruction is for a parallel set of normally closed contacts, thus the instruction is ORI X401. The last step is the output, hence OUT Y430. The instruction list is thus: LDI X400
ORI X401
OUT Y430
Figure 6.4(b) shows the NAND gate in Siemens notation. The instruction list is then:
AN I0.1
ON I0.2
= Q2.0
6.1.2 Branch codes
The Exclusive OR (XOR) gate shown in Figure 6.5(a) in Mitsubishi notation has two parallel arms with an AND situation in each arm.
In such a situation Mitsubishi uses an ORB instruction to indicate ‘OR together parallel branches’. The first instruction is for a normally open pair of contacts X400. The next instruction is for a series set of normally closed contacts X401, hence ANI X401. After reading the first two instructions, the third instruction starts a new line. It is recognised as a new line because it starts with LDI, all new lines starting with LD or LDI. But the first line has not been ended by an output. The
PLC thus recognises that a parallel line is involved for the second line and reads together the listed elements until the ORB instruction is reached. The mnemonic ORB (OR branches/blocks together) indicates to the PLC that it should OR the results of the first and second instructions with that of the new branch with the third and fourth instructions. The list concludes with the output OUT Y430. The instruction list would thus be entered as:
LD X400
ANI X401
LDI X400
AND X401
ORB
OUT Y430
Figure 6.5(b) shows the Siemens version of XOR gate. Brackets are used to indicate that certain instructions are to be carried out as a block. They are used in the same way as brackets in any mathematical equation. For example, (2 + 3)/4 means that the 2 and 3 must be added before dividing by 4. Thus with the Siemens instruction list we have in step 0 the instruction A(. The brackets close in step 3. This means that the A in step 0 is applied only after the instructions in steps 1 and 2 have been applied.
The IEC 1131-3 standard for such programming is to use brackets in the way used in the above Siemens example.
Figure 6.6(a) shows a circuit, in Mitsubishi notation, which can be considered as two branched AND blocks. The instruction used here is ANB. The instruction list is thus: Figure 6.6(b) shows the same circuit in Siemens notation. Such a program is written as an instruction list using brackets. The A instruction in step 0 applies to the result of steps 1 and 2. The A instruction in step 4 applies to the result of steps 5 and 6. The program instruction list is thus:
Figure 6.7(a) shows a ladder, in Mitsubishi notation, with two rungs. In writing the instruction list we just write the instructions for each line in turn. The instruction LD or LDI indicates to the PLC that a new rung is starting. The instruction list is thus:
LD X400
OUT Y430
LDI X400
OUT Y431
The system is one where when X400 is not activated, there is an output from Y431 but not Y430. When X400 is activated, there is then an output from Y430 but not Y431.
Figure 6.7(b) shows the same program in Siemens notation. The = instruction indicates the end of a line. The A or AN instruction does not necessarily indicate the beginning of a rung since the same instruction is used for AND and AND NOT. The instruction list is then:
A I0.0
= Q2.0
AN I0.0
= Q2.1
6.1.4 Programming examples
The following tasks are intended to illustrate the application of the programming techniques given in this section and are the examples for which ladder diagrams and function block diagrams were derived in Section 5.7. See that section for an explanation of the ladder diagrams; here we just show the instruction lists relating to the programs.
A signal lamp is required to be switched on if a pump is running and the pressure is satisfactory, or if the lamp test switch is closed. Figure 6.8 shows the ladder program and the related instruction list.
For a valve which is to be operated to lift a load when a pump is running and either the lift switch is operated or a switch operated indicating
that the load has not already been lifted and is at the bottom of its lift channel, Figure 6.9 shows the ladder program and the related instruction list.
For a system where there has to be no output when any one of four sensors gives an output, otherwise there is to be an output, Figure 6.10 shows the ladder program and the instruction list.
6.2 Sequential function
If we wanted to describe a traffic lamp sequence, one way we could do this would be to represent it as a sequence of functions or states such as red light state and green light state and the inputs and outputs to each state. Figure 6.11 illustrates this. State 0 has an input which is triggered after the green light has been on for 1 minute and an output of red light on. State 1 has an input which is triggered after the red light has been on for 1 minute and an output of green light on.
The term sequential function chart (SFC) is used for a pictorial representation of a system’s operation to show the sequence of the events involved in its operation. SFC charts have the following elements:
1 The operation is described by a number of separate sequentially connected states or steps which are represented by rectangular boxes, each representing a particular state of the system being controlled. The initial step in a program is represented differently to the other steps, Figure 6.1
2 shows its representation.
2 Each connecting line between states has a horizontal bar representing the transition condition that has to be realised before the system can move from one state to the next. Two steps can never be directly connected, they must always be separated by a transition. Two transitions can never directly follow from one to another, they must always be separated by a step.
3 When the transfer conditions to the next state are realised then thenext state or step in the program occurs.
4 The process thus continues from one state to the next until the complete machine cycle is completed.
5 Outputs/actions at any state are represented by horizontally linked boxes and occur when that state has been realised. As an illustration, Figure 6.13 shows part of an SFC and its equivalent ladder diagram. Figure 6.13 SFC and equivalent ladder diagram
As an illustration of the principles of SFC, consider the situation with, say, part of the washing cycle of a domestic washing machine where the drum is to be filled with water and then when full a heater has to be switched on and remain on until the temperature reaches the required level. Then the drum is to be rotated for a specified time. We have a sequence of states which can be represented in the manner shown in Figure 6.14.
6.2.1 Branching and convergence
Selective branching is illustrated in Figure 6.15 and allows for different states to be realised depending on the transfer condition that occurs.
Parallel branching (Figure 6.16), represented by a pair of horizontal lines, allows for two or more different states to be realised and proceed simultaneously.
Figures 6.17 and 6.18 show how convergence is represented by an SFC. In Figure 6.17 the sequence can go from state 2 to state 4 if IN 4 occurs or from state 3 to state 4 if IN 5 occurs. In Figure 6.18 the sequence can go simultaneously from both state 2 and state 3 to state 4 if IN 4 occurs.
6.2.2 Actions
With states, there is an action or actions which have to be performed. Such actions, like the outputs in the above example, are depicted as rectangular boxes attached to the state. The behaviour of the action can be given using a ladder diagram, function block diagram, instruction list
or structured text. Thus, where a ladder diagram is used, the behaviour of the action is shown by the ladder diagram being enclosed within the action box. The action is then activated when there is a power flow into the action box. Figure 6.20 illustrates this.
Action boxes are generally preceded by qualifiers to specify the conditions to exist for the action. In the absence of a qualifier or the qualifier N, the action is not stored and executed continually while the associate state is active. The qualifier P is used for a pulse action that executes only once when a step is activated. The qualifier D is used for a time delayed action that only starts after a specified period. The qualifier L is used for a time limited action which terminates after a specified period (Figure 6.21).
6.3 Structured text
Structured text is a programming language that strongly resembles the programming language PASCAL. Programs are written as a series of statements separated by semicolons. The statements use predefined statements and subroutines to change variables, these being defined values, internally stored values or inputs and outputs.
Assignment statements are used to indicate how the value of a variable it to be changed, e.g.
Light := SwitchA;
is used to indicate that a light is to have its ‘value’ changed, i.e. switched on or off, wh en switch A changes its ‘value’, i.e. is on or off. The general format of an assignment statement is:
X := Y;
where Y represents an expression which produces a new value for the variable X. Another example is:
Light :- SwitchA OR SwitchB;
to indicate that the light is switched on by either switch A or switch B.
Table 6.2 shows some of the operators, like the OR in the above statement, that are used in structured text programs, and their relative precedence when an expression is being evaluated. For example: InputA = 6
InputB = 4
InputC = 2
OutputQ := InputA/3 + InputB/(3 ? InputC)
has (3 – InputC) evaluated before its value is used as a divisor so the second part of the OutputQ statement is 4/(3 – 2) = 4. Division has precedence over addition and so the first part of the statement is evaluated before the addition, i.e. 6/3. So we have for OutputQ the value 2 + 1 = 3.
Structured text is not case sensitive, thus lower case or capital letters can be used as is felt necessary to aid clarity. Likewise spaces are not necessary but can be used to aid clarity, likewise indenting lines. All the identities of directly represented variables start with the % character and is followed by one or two letter code to identify whether the memory location is associated with inputs, outputs or internal memory and whether it is bits, bytes or words, e.g.
%IX100 (*Input memory bit 100*)
%ID200 (*Input memory word 200*)
%QX100 (*Output memory bit 100*)
The first letter is I for input memory location, Q for output memory location, M for internal memory. The second letter is X for bit, B for byte (8 bit), W for word (16 bits), D for double word (32 bits), L for long word (64 bits).
AT is used to fix the memory location for a variable. Thus we might have:
Input1 AT %IX100; (*Input1 is located at input memory bit 100*)
中等分辨率制备分离的 快速色谱技术 W. Clark Still,* Michael K a h n , and Abhijit Mitra Departm(7nt o/ Chemistry, Columbia Uniuersity,1Veu York, Neu; York 10027 ReceiLied January 26, 1978 我们希望找到一种简单的吸附色谱技术用于有机化合物的常规净化。这种技术是适于传统的有机物大规模制备分离，该技术需使用长柱色谱法。尽管这种技术得到的效果非常好，但是其需要消耗大量的时间，并且由于频带拖尾经常出现低复原率。当分离的样本剂量大于1或者2g时，这些问题显得更加突出。近年来，几种制备系统已经进行了改进，能将分离时间减少到1-3h，并允许各成分的分辨率ΔR f≥（使用薄层色谱分析进行分析）。在这些方法中，在我们的实验室中，媒介压力色谱法1和短柱色谱法2是最成功的。最近，我们发现一种可以将分离速度大幅度提升的技术，可用于反应产物的常规提纯，我们将这种技术称为急骤色谱法。虽然这种技术的分辨率只是中等（ΔR f≥），而且构建这个系统花费非常低，并且能在10-15min内分离重量在的样本。4 急骤色谱法是以空气压力驱动的混合介质压力以及短柱色谱法为基础，专门针对快速分离，介质压力以及短柱色谱已经进行了优化。优化实验是在一组标准条件5下进行的，优化实验使用苯甲醇作为样本，放在一个20mm*5in.的硅胶柱60内，使用Tracor 970紫外检测器监测圆柱的输出。分辨率通过持续时间（r）和峰宽（w,w/2）的比率进行测定的（Figure 1），结果如图2-4所示，图2-4分别放映分辨率随着硅胶颗粒大小、洗脱液流速和样本大小的变化。
五、外文资料翻译 Stress and Strain 1.Introduction to Mechanics of Materials Mechanics of materials is a branch of applied mechanics that deals with the behavior of solid bodies subjected to various types of loading. It is a field of study that i s known by a variety of names, including “strength of materials” and “mechanics of deformable bodies”. The solid bodies considered in this book include axially-loaded bars, shafts, beams, and columns, as well as structures that are assemblies of these components. Usually the objective of our analysis will be the determination of the stresses, strains, and deformations produced by the loads; if these quantities can be found for all values of load up to the failure load, then we will have obtained a complete picture of the mechanics behavior of the body. Theoretical analyses and experimental results have equally important roles in the study of mechanics of materials . On many occasion we will make logical derivations to obtain formulas and equations for predicting mechanics behavior, but at the same time we must recognize that these formulas cannot be used in a realistic way unless certain properties of the been made in the laboratory. Also , many problems of importance in engineering cannot be handled efficiently by theoretical means, and experimental measurements become a practical necessity. The historical development of mechanics of materials is a fascinating blend of both theory and experiment, with experiments pointing the way to useful results in some instances and with theory doing so in others①. Such famous men as Leonardo da Vinci(1452-1519) and Galileo Galilei (1564-1642) made experiments to adequate to determine the strength of wires , bars , and beams , although they did not develop any adequate theo ries (by today’s standards ) to explain their test results . By contrast , the famous mathematician Leonhard Euler(1707-1783) developed the mathematical theory any of columns and calculated the critical load of a column in 1744 , long before any experimental evidence existed to show the significance of his results ②. Thus , Euler’s theoretical results remained unused for many years, although today they form the basis of column theory. The importance of combining theoretical derivations with experimentally determined properties of materials will be evident theoretical derivations with experimentally determined properties of materials will be evident as we proceed with
Programmable logic controller A programmable logic controller (PLC) or programmable controller is a digital computer used for automation of electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, or lighting fixtures. PLCs are used in many industries and machines. Unlike general-purpose computers, the PLC is designed for multiple inputs and output arrangements, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact. Programs to control machine operation are typically stored in battery-backed or non-volatile memory. A PLC is an example of a real time system since output results must be produced in response to input conditions within a bounded time, otherwise unintended operation will result. 1.History The PLC was invented in response to the needs of the American automotive manufacturing industry. Programmable logic controllers were initially adopted by the automotive industry where software revision replaced the re-wiring of hard-wired control panels when production models changed. Before the PLC, control, sequencing, and safety interlock logic for manufacturing automobiles was accomplished using hundreds or thousands of relays, cam timers, and drum sequencers and dedicated closed-loop controllers. The process for updating such facilities for the yearly model change-over was very time consuming and expensive, as electricians needed to individually rewire each and every relay. In 1968 GM Hydramatic (the automatic transmission division of General Motors) issued a request for proposal for an electronic replacement for hard-wired relay systems. The winning proposal came from Bedford Associates of Bedford, Massachusetts. The first PLC, designated the 084 because it was Bedford Associates' eighty-fourth project, was the result. Bedford Associates started a new company dedicated to developing, manufacturing, selling, and servicing this new product: Modicon, which stood for MOdular DIgital CONtroller. One of the people who worked on that project was Dick Morley, who is considered to be the "father" of the PLC. The Modicon brand was sold in 1977 to Gould Electronics, and later acquired by German Company AEG and then by French Schneider Electric, the current owner. One of the very first 084 models built is now on display at Modicon's headquarters in North Andover, Massachusetts. It was presented to Modicon by GM, when the unit was retired after nearly twenty years of uninterrupted service. Modicon used the 84
华北电力大学科技学院 毕业设计（论文）附件 外文文献翻译 学号：121912020115姓名：彭钰钊 所在系别：动力工程系专业班级：测控技术与仪器12K1指导教师：李冰 原文标题：Infrared Remote Control System Abstract 2016 年 4 月 19 日
红外遥控系统 摘要 红外数据通信技术是目前在世界范围内被广泛使用的一种无线连接技术，被众多的硬件和软件平台所支持。红外收发器产品具有成本低，小型化，传输速率快，点对点安全传输，不受电磁干扰等特点，可以实现信息在不同产品之间快速、方便、安全地交换与传送，在短距离无线传输方面拥有十分明显的优势。红外遥控收发系统的设计在具有很高的实用价值，目前红外收发器产品在可携式产品中的应用潜力很大。全世界约有1亿5千万台设备采用红外技术，在电子产品和工业设备、医疗设备等领域广泛使用。绝大多数笔记本电脑和手机都配置红外收发器接口。随着红外数据传输技术更加成熟、成本下降，红外收发器在短距离通讯领域必将得到更广泛的应用。 本系统的设计目的是用红外线作为传输媒质来传输用户的操作信息并由接收电路解调出原始信号，主要用到编码芯片和解码芯片对信号进行调制与解调，其中编码芯片用的是台湾生产的PT2262，解码芯片是PT2272。主要工作原理是：利用编码键盘可以为PT2262提供的输入信息，PT2262对输入的信息进行编码并加载到38KHZ的载波上并调制红外发射二极管并辐射到空间，然后再由接收系统接收到发射的信号并解调出原始信息，由PT2272对原信号进行解码以驱动相应的电路完成用户的操作要求。 关键字：红外线；编码；解码；LM386；红外收发器。 1 绪论
New technique of the computer network Abstract The 21 century is an ages of the information economy, being the computer network technique of representative techniques this ages, will be at very fast speed develop soon in continuously creatively, and will go deep into the people's work, life and study. Therefore, control this technique and then seem to be more to deliver the importance. Now I mainly introduce the new technique of a few networks in actuality live of application. keywords Internet Network System Digital Certificates Grid Storage 1. Foreword Internet turns 36, still a work in progress Thirty-six years after computer scientists at UCLA linked two bulky computers using a 15-foot gray cable, testing a new way for exchanging data over networks, what would ultimately become the Internet remains a work in progress. University researchers are experimenting with ways to increase its capacity and speed. Programmers are trying to imbue Web pages with intelligence. And work is underway to re-engineer the network to reduce Spam (junk mail) and security troubles. All the while threats loom: Critics warn that commercial, legal and political pressures could hinder the types of innovations that made the Internet what it is today. Stephen Crocker and Vinton Cerf were among the graduate students who joined UCLA professor Len Klein rock in an engineering lab on Sept. 2, 1969, as bits of meaningless test data flowed silently between the two computers. By January, three other "nodes" joined the fledgling network.
在广州甚至广东的住宅小区电气设计中,一般都会涉及到小区的高低压供配电系统的设计.如10kV高压配电系统图,低压配电系统图等等图纸一大堆.然而在真正实施过程中,供电部门(尤其是供电公司指定的所谓电力设计小公司)根本将这些图纸作为一回事,按其电脑里原有的电子档图纸将数据稍作改动以及断路器按其所好换个厂家名称便美其名曰设计(可笑不?),拿出来的图纸根本无法满足电气设计的设计意图,致使严重存在以下问题:(也不知道是职业道德问题还是根本一窍不通) 1.跟原设计的电气系统货不对板,存在与低压开关柜后出线回路严重冲突,对实际施工造成严重阻碍,经常要求设计单位改动原有电气系统图才能满足它的要求(垄断的没话说). 2.对消防负荷和非消防负荷的供电(主要在高层建筑里)应严格分回路(从母线段)都不清楚,将消防负荷和非消防负荷按一个回路出线(尤其是将电梯和消防电梯,地下室的动力合在一起等等,有的甚至将楼顶消防风机和梯间照明合在一个回路,以一个表计量). 3.系统接地保护接地型式由原设计的TN-S系统竟曲解成"TN-S-C-S"系统(室内的还需要做TN-C,好玩吧?),严格的按照所谓的"三相四线制"再做重复接地来实施,导致后续施工中存在重复浪费资源以及安全隐患等等问题.. ............................(违反建筑电气设计规范等等问题实在不好意思一一例举,给那帮人留点混饭吃的面子算了) 总之吧,在通过图纸审查后的电气设计图纸在这帮人的眼里根本不知何物,经常是完工后的高低压供配电系统已是面目全非了,能有百分之五十的保留已经是谢天谢地了. 所以.我觉得:住宅建筑电气设计,让供电部门走!大不了留点位置,让他供几个必需回路的电,爱怎么折腾让他自个怎么折腾去.. Guangzhou, Guangdong, even in the electrical design of residential quarters, generally involving high-low cell power supply system design. 10kV power distribution systems, such as maps, drawings, etc. low-voltage distribution system map a lot. But in the real implementation of the process, the power sector (especially the so-called power supply design company appointed a small company) did these drawings for one thing, according to computer drawings of the original electronic file data to make a little change, and circuit breakers by their the name of another manufacturer will be sounding good design (ridiculously?), drawing out the design simply can not meet the electrical design intent, resulting in a serious following problems: (do not know or not know nothing about ethical issues) 1. With the original design of the electrical system not meeting board, the existence and low voltage switchgear circuit after qualifying serious conflicts seriously hinder the actual construction, often require changes to the original design unit plans to meet its electrical system requirements (monopoly impress ). 2. On the fire load and fire load of non-supply (mainly in high-rise building in) should be strictly sub-loop (from the bus segment) are not clear, the fire load and fire load of non-qualifying press of a circuit (especially the elevator and fire elevator, basement, etc.
哈尔滨工业大学毕业设计（论文） 英文原文（原文也可以直接将PDF版打印） ASSESSING CREDIT OR DETERMINING QUANTITY? THE EVOLVING ROLE OF RATING AGENCIES Lynnette D. Purda* This version: April 21, 2011 Abstract Over the past ten years, credit rating agencies have come under intense criticism from both practitioners and academics, first for their failure to identify problems resulting in bankruptcies at Enron and Worldcom and second for providing overly optimistic ratings for structured finance products. While many investors question the value of rating agencies in light of these criticisms, they have proven remarkably resilient. This paper provides a brief background on how rating agencies secured competitive advantages in evaluating credit quality. It then reviews the empirical evidence on the information content of ratings given these advantages. I argue that the information content of ratings stems from two intertwined sources: 1) information related to credit quality and 2) information related to the firm’s ability to access debt. Based on this evidence, I suggest that the dominant role for ratings today is as a benchmark for financial contracting. In this way, ratings remain influential in establishing the supply and demand of debt securities. 译文 评级机构的发展的作用评估信用还是决定数量？ 本文：2011.4.21 摘要 在过去的十年，信用评级机构一直处于来自实践者和学者的激烈的批评中，首先他们未能发现问题，导致安然和世通破产；其次对结构性金融产品提供过于乐观的评级。虽然许多投资者因为这些批评对评级机构的价值提出了质疑，但他们仍然被证明是相当有活力的。这篇文章首先在评估机构如何在信用评级质量中获得竞争优势提供一个简单地背景介绍，然后考虑到这些优势回顾了一些信息内容方面的评级经验证据。个人认为信息内容的评级来自两种交织在一起（错综复杂）的来源：1）和信贷质量相关的信息；2)和公司获取债务资本能力相关的信息。以此为据，我建议当前评级的主导作用是作为基准的金融收缩。以这种方式，在建立债券的供应和需求方面评级仍然是有效的。 - -1
https://www.doczj.com/doc/ab2682579.html,/finance/company/consumer.html Consumer finance company The consumer finance division of the SG group of France has become highly active within India. They plan to offer finance for vehicles and two-wheelers to consumers, aiming to provide close to Rs. 400 billion in India in the next few years of its operations. The SG group is also dealing in stock broking, asset management, investment banking, private banking, information technology and business processing. SG group has ventured into the rapidly growing consumer credit market in India, and have plans to construct a headquarters at Kolkata. The AIG Group has been approved by the RBI to set up a non-banking finance company (NBFC). AIG seeks to introduce its consumer finance and asset management businesses in India. AIG Capital India plans to emphasize credit cards, mortgage financing, consumer durable financing and personal loans. Leading Indian and international concerns like the HSBC, Deutsche Bank, Goldman Sachs, Barclays and HDFC Bank are also waiting to be approved by the Reserve Bank of India to initiate similar operations. AIG is presently involved in insurance and financial services in more than one hundred countries. The affiliates of the AIG Group also provide retirement and asset management services all over the world. Many international companies have been looking at NBFC business because of the growing consumer finance market. Unlike foreign banks, there are no strictures on branch openings for the NBFCs. GE Consumer Finance is a section of General Electric. It is responsible for looking after the retail finance operations. GE Consumer Finance also governs the GE Capital Asia. Outside the United States, GE Consumer Finance performs its operations under the GE Money brand. GE Consumer Finance currently offers financial services in more than fifty countries. The company deals in credit cards, personal finance, mortgages and automobile solutions. It has a client base of more than 118 million customers throughout the world
英文翻译 A comprehensive overview of substations Along with the economic development and the modern industry developments of quick rising, the design of the power supply system become more and more completely and system. Because the quickly increase electricity of factories, it also increases seriously to the dependable index of the economic condition, power supply in quantity. Therefore they need the higher and more perfect request to the power supply. Whether Design reasonable, not only affect directly the base investment and circulate the expenses with have the metal depletion in colour metal, but also will reflect the dependable in power supply and the safe in many facts. In a word, it is close with the economic performance and the safety of the people. The substation is an importance part of the electric power system, it is consisted of the electric appliances equipments and the Transmission and the Distribution. It obtains the electric power from the electric power system, through its function of transformation and assign, transport and safety. Then transport the power to every place with safe, dependable, and economical. As an important part of power’s transport and control, the transformer substation must change the mode of the traditional design and control, then can adapt to the modern electric power system, the development of modern industry and the of trend of the society life. Electric power industry is one of the foundations of national industry and national economic development to industry, it is a coal, oil, natural gas, hydropower, nuclear power, wind power and other energy conversion into electrical energy of the secondary energy industry, it for the other departments of the national economy fast and stable development of the provision of adequate power, and its level of development is a reflection of the country's economic development an important indicator of the level. As the power in the industry and the importance of the national economy, electricity transmission and distribution of electric energy used in these areas is an indispensable component.。Therefore, power transmission and distribution is critical. Substation is to enable superior power plant power plants or power after adjustments to the lower load of books is an important part of power transmission. Operation of its functions, the capacity of a direct impact on the size of the lower load power, thereby affecting the industrial production and power consumption.Substation system if a link failure, the system will protect the part of action. May result in power outages and so on, to the production and living a great disadvantage. Therefore, the substation in the electric power system for the protection of electricity reliability,
International Journal of Minerals, Metallurgy and Materials Volume 17, Number 4, August 2010, Page 500 DOI: 10.1007/s12613-010-0348-y Corresponding author: Zhuan Li E-mail: li_zhuan@https://www.doczj.com/doc/ab2682579.html, ? University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg 2010 Preparation and properties of C/C-SiC brake composites fabricated by warm compacted-in situ reaction Zhuan Li, Peng Xiao, and Xiang Xiong State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China (Received: 12 August 2009; revised: 28 August 2009; accepted: 2 September 2009) Abstract: Carbon fibre reinforced carbon and silicon carbide dual matrix composites (C/C-SiC) were fabricated by the warm compacted-in situ reaction. The microstructure, mechanical properties, tribological properties, and wear mechanism of C/C-SiC composites at different brake speeds were investigated. The results indicate that the composites are composed of 58wt% C, 37wt% SiC, and 5wt% Si. The density and open porosity are 2.0 g·cm–3 and 10%, respectively. The C/C-SiC brake composites exhibit good mechanical properties. The flexural strength can reach up to 160 MPa, and the impact strength can reach 2.5 kJ·m–2. The C/C-SiC brake composites show excellent tribological performances. The friction coefficient is between 0.57 and 0.67 at the brake speeds from 8 to 24 m·s?1. The brake is stable, and the wear rate is less than 2.02×10?6 cm3·J?1. These results show that the C/C-SiC brake composites are the promising candidates for advanced brake and clutch systems. Keywords: C/C-SiC; ceramic matrix composites; tribological properties; microstructure [This work was financially supported by the National High-Tech Research and Development Program of China (No.2006AA03Z560) and the Graduate Degree Thesis Innovation Foundation of Central South University (No.2008yb019).] 温压-原位反应法制备C / C-SiC刹车复合材料的工艺和性能 李专，肖鹏，熊翔 粉末冶金国家重点实验室，中南大学，湖南长沙410083，中国（收稿日期：2009年8月12日修订：2009年8月28日;接受日期：2009年9月2日） 摘要：采用温压?原位反应法制备炭纤维增强炭和碳化硅双基体(C/C-SiC)复合材