对象类别 object categories
好的 我们继续 Alright, let’s move on.
现在有趣的是 Now, interesting enough is that
我们要区别不同类型的物体 when we try to distinguish between different types of objects,
物体通常多种多样 the object actually there’re different types.
甚至你看我们刚才说过的东西 Even you look at the things we just went through,
螺丝或上螺丝 screw or drive screw.
螺丝是一个实体物体 Screw is a real physical object.
但是当你说储存能量 能量是一个物体 But when you say store energy, energy is an object,
但它又不是螺丝这样的物体 but it’s not an object like a screw. Right?
同样的 当你说转化能量 And also when we say convert energy,
将化学能转化为机械能 convert chemical energy into mechanical energy.
能量也是物体 Energy are also object.
所以如果你真的沿着这个方向思考 So if you really go forward, think along this direction,
我们就可以将不同的物体分类 对吗 we can actually categorize different types of objects. All right?
分类的方式有很多 Now, several ways to categorize them.
我们可以看看能量 We can see that there’re something called energy.
由于我们在讨论工程设计 Ok. Since we are talking about engineering design,
不管什么时候你做工程设计都离不开能量 whenever you do engineering design you have to work with energy,
因为这是物质运动的原因 对吗 because that is the source of movement. Alright?
因此我们常用这个图标来表示能量 So energy, usually we use this graphical mark,
箭头图标 它叫做实线箭头 graphical indicates arrow, it’s called solid arrow,
实线箭头用来表示能量流 solid arrow is used to indicate what is energy flow. Ok, energy flow.
或者说用箭头代表流动 Or say use the arrow to indicate the flow.
现在又有另一种物体 叫做原料 Now there’s another type of object, it’s called material. Alright?
因此有原料用来加工 So you have material goes in,
比如转变一些原料 将木头变成椅子 for instance, you change some material, change wood into chair.
还可以转变瓦斯 或汽油 And use materials to change gas, gasoline
所有这些都是原料 and all those things you can say those are materials.
所以基本上这些都是实体 对吗 So basically it’s a physical thing. Ok?
在功能图表中 In functional diagrams,
对于实体物体 the physical thing
我们通常用空心箭头来表示物质流 we usually use either a hollow arrow to indicate this is a material flow
或者用一个粗箭头 or we use a very thick arrow. OK.
用右边这个粗箭头 它更粗一些 The right thick arrow to indicate...this is the one thicker.
所以比较这两个 So comparing this with this,
你会发现这个细一些 这个粗一些 you know this is thinner, this is thicker.
我们用粗箭头来表示物质 We use a thick arrow to indicate there’s a material,
另外还有一类物体 叫做信号 and there’s another type of material object. It’s called signal. Ok?
什么是信号 有些人可能会问 What is signal? Sometimes people will say:
信号是信息吗 很正确 oh, signal, is that information? Precisely.
信号可以用这种虚线来表示 So signal can be indicated use this type of...it’s called broken lines.
好的 也有人用点状线表示 这也可以 Ok, sometimes people use dotted lines. But that’s fine.
但是最好是虚线 Broken line is better.
现在我们已经有3种对物体的分类了 And now you see we have 3 categories of different type of objects.
现在如果你把以上信息放在一起 Now if you put this together
再看看怎样具体描述功能 to see how you can describe a very specific function,
就有这样一个完整的螺丝刀功能描述 here is a complete description of the function of a screw driver.
上螺丝在中间 Now drive screw is in the center,
根据我们的描述方法 这是一个动词加一个物体 it’s our description, with a verb and an object.
上螺丝需要什么呢 What does it take to drive a screw?
需要人力 这里是人力 It takes human energy. Here’s human energy.
需要人的能量去做 需要螺丝 Takes human energy to do it. You have to a screw.
螺丝一定要拿在手上 The screw has to be in hand.
所以作为输入 这里是一个螺丝 对吗 So as input, there’s a screw. Alright?
你把螺丝放好 So you put the screw in,
同时手拿螺丝刀的人必须要能看到或知道 at the same time, the person who drive the screw must be able to see or to know
这个螺丝是已经放进去了 还是还在外面 whether the screw is still outside or already inside
是太松 还是已经够紧 or still too loose or it’s already very tight.
所以在最开始应该有一个信号证明它很松 So there must be signal at the very beginning, it’s very loose,
在最后有信号证明它已经上紧了 at the very end, you confirm that it’s very tight.
这样就能确定螺丝上好了 So the screw driving is confirmed.
有能量流入 就有能量流出 Now energy goes in, energy also goes out.
从热量来看 In terms of heat,
如果你在上螺丝的时候摸摸螺丝钉 when you drive a screw, actually if you touch the screw,
你会感受到温度变了 you feel that there’s a temperature difference.
另外还有一种潜在能量 And also there’s a potential,
假设把螺丝上到木头里 assuming you drive a screw into a wood,
就会有一种潜在能量存在于螺丝和木头之间 then there’s a potential energy between your screw and the wood.
这个很小的能量也会呆在那里 So that little energy also stays there.
螺丝钉还在那里 And the screw is still there.
螺丝钉进去 螺丝钉出来 Ok, screw goes in, screw goes out.
最终在哪里？ 它会呆在木头里 Where does it go? It stay in the wood.
如果你卸螺丝 把它拿出来 If you drive out, remove the screw,
螺丝钉就在你手里 then the screw is in your hand.
就是这样 Those are the things.
你会在某个信号出现时 知道该停止上螺丝 And you do know there’s a signal which tells you when to stop driving.
上螺丝 对吗 Driving the screw, right?
所以在某一点 你知道该停止了 The point you know where it's the point to stop,
这就是你接收信号的时候 that’s exactly where you receive the signal.
所以如果你看这张图片 So if you look at this picture,
如果你看右下角 you see that in lower right hand corner,
是一张完整的功能描述图 you see that’s one complete description of a function.
你可能会说 为什么要把它弄得如此复杂 You may say: why do we bother to make it so complicated?
答案是它需要这样完整的图示 The answer is that it needs to have the completeness of that level,
在接下来 当你要用功能概念来做工程设计时 so that later on when you use the notion of function to do engineering design,
所有事情都会变得很精准 you will get everything accurate,
这样你就不会错失重点和其他重要信息 so you don’t lose the point, so you don’t lose important points.