Our data center (SVColo) performed an upgrade to their core network switch this evening. Something went wrong, and the operation took 30 minutes instead of 5. We apologize for the problem.
Jason: we would love to host FriendFeed but any hoster will screw up from time to time so I would rather win their business on the strength of our technology and service. Our CEO puts his personal cell phone out there (I don't know of any other hosting company CEO that does that, plus mine is +1-425-205-1921). not to mention I have some major motivation to make sure FriendFeed stays up. :-)
- Robert Scoble
Compete with Wave and let people run their own Friendfeed servers.
- Vezquex
Thanks! I almost sent SOS via Twitter...but u guys were fast! :D
- Roshan Ramachandran
Oh, and it was nice of you guys to arrange your downtime for when I was flying and off the net! :-)
- Robert Scoble
The upside is I saw the 'new and improved' twitter web interface for the first time. When do I have time to do that normally :D
- Micah
@scoble, that's just it. I've only known Rackspace to screw up once and it was due to some guy driving a car into the data center. Plus, all the other perks you mentioned.
- Jason Cronkhite
请看黑板第二张图,这是一幅波尔的原子模型示意图(这个模型其实是错的,但比较好理解,先将就着,以后有机会再解释错在哪儿),假想这是就是氢原子,中心的绿豆就是原子核(包括一个中子+一个质子),带一个单位的正电荷,原子核以外就是电子(只有一个)围绕着原子核自由地翱翔着---其实不那么自由了,电子其实只能停留在图中示意的n=1,2,3....的某条轨道上(虚线所示的圆圈),n的数值越大的轨道对应的电子的能量就越高,即E3>E2>E1。
- Paul
如图所示,电子在n=3的轨道坠落到n=2的轨道上时,电子的能量降低了dE=E3-E2,可是能量是守恒的,这个能量哪去了呢,就是变成光辐射出去了,这时光的能量就是这个dE了,由于爱因斯坦发现的公式,光的能量=h(普朗克常数)X f(光的频率--正取的写法是图中的那个貌似v的符号,我打不出来),因此,这个发射出去的光具有唯一确定的频率,这就是为什么第一张图上氢的光谱是一条条的线,每一条线都对应氢原子中的电子从某个轨道坠落到另外一个轨道时发出的光。
- Paul
上述的简介其实就已经隐含了量子的概念了,大家看出来了吗?提示一下,所谓量子,最初引入的时候描述的就是一份一份的能量,就是说能量必须是一份一份的,而不能是连续变化的。
- Paul
先简单自问自答一下上面那个问题:那个电子为什么会以及何时会落入一个较低的轨道呢?这个事件可以预测吗?答案是不知道,不可预测,电子在轨道中的这种跳跃毫无理由,不可预测,是一个完美的随机事件。注意我上一个话题--因果关系,电子的这种行为就是一种没有因果关系的事件。
- Paul
电子的这种自发的,完全随机的向下跳跃其实有着对应的逆过程。当处于n=2轨道的电子被具有dE=E3-E2的光照射时,电子吸收这个能量就能跃迁到n=3的轨道上。
- Paul
这个过程又反映了光具有量子的性质,那个电子必须遇上一个刚好有那么多能量的光子才能吸收它的能量,如果照射的光子具有的能量是上述能量的1.5倍,电子是不会从这个光子那里只吸收1份能量而让那个光子带着余下的0.5份能量溜走的。光子必须全部交出它的能量,否则就不会交出。这就是所谓量子的基本概念了,能量必须一份一份地(准确地说是某个最小的能量值的整数倍)交换。
- Paul
简要地小结一下本课的主题就是,光是一种量子,光具有能量,能量必须一份一份地交换,所以,在量子力学里,光也叫光子(photon),粗糙地说,你可以把光想象为一个一个的粒子---光子。
- Paul
最要紧的是要知道,光子(以及其他的一切量子),其行为的本质特征就是完美的随机性,量子的行为是完全不遵循因果律,所有的量子的现象都是随机现象,所以,不用去问它们为什么会这样或那样。清楚这一点我们就可以开始进入正式的热身阶段了。
- Paul
非也,非也。kelvin很细心啊,这可不是题外话。能量守恒最终是一个统计值,而量子原理中的不确定性原理更基本--在此原理下,电子可以有一个能量上的短时间的涨落,可以理解为电子瞬间借入了一些能量,但必须在一个很短的时间内归还,于是电子有一定的几率自发地跃迁到高能轨道,随后很快回落(归还借入的能量),在长过这个时间的时间跨度来看电子的能量仍然守恒。
- Paul
from email
所以啊,在量子世界里,一切的现象和事件都是几率性的,最终某个具体的事件的发生总是随机的,正是因为这种随机性,必须也只能以几率描述量子,几率正是理解量子的核心所在。几率这个概念本身就是对大量的随机事件的一种处理方式----以后还要再介绍这个问题。
- Paul
from email
我们在经验世界中获得的一切概念,有无、这里那里、多少都是幻象。比如能量,如果你在很长一个时间跨度里(反复)测量电子的能量,测量值会趋向(收敛到)一个非常恒定的数值--这就是测量的含义,然而在更短的时间里,这个测量值就会变得非常飘忽,时间越短,能量的波动就越大(不确定性越高)。量子的一切属性总是在随机地变化。
- Paul
广大不明真想的群众可能在不同的场合听说过这样一种谣传--量子力学很难懂,我得澄清,这真不是谣言,事实就是这样!关于这个话题有许多趣话。玻尔说:“谁要是第一次听到量子理论时没有感到困惑,那他一定没听懂。”费曼说:“世界上是否只有12个人懂相对论我不清楚,但是我能蛮有把握地说:世界上没有人懂量子理论。”(“I think I can safely say that nobody understands quantum mechanics”)“如果有人说他懂量子力学,那他是在撒谎。”我认识的一位前辈有一次很惭愧地说他一生中前后学过4次量子力学仍然没学懂。
- Paul
正因为如此,我怀着异常激动和兴奋的心情投入个科普题目,一方面可以幸灾乐祸地把大家搞得头晕脑涨,二来即便说错了也不会有丝毫的内疚感--反正连那些诺贝尔得主都说没有人懂量子理论。请大家一定要事先准备好一些特弱智的节目(比如ET主持的访谈节目)课后看,以便平复那颗严重受损的心灵。
- Paul
某书某章介绍量子理论是说找来一千个哲学家,给他们一千年的时间也想不出量子力学这么古怪的东西,量子问题之难不仅在于其使用复杂的数学工具,更重要的原因在于与其相关的现象和规律严重地背离我们在经验世界中形成的直觉和思维方式,可以说,面对量子问题,一个正常的人一旦企图对进行任何的想像都会立即陷入不可自拔的紊乱中。从某个角度来说,理解量子力学最好的方法就是不要疑问,立即全盘接受。
- Paul
因而我们从经验世界(物理上称之为经典的世界,这两者基本相等)所归纳的经验,抽象的思想其实是非常非常狭隘的,这些规律仅仅适合我们日常生活的狭小时空中,而那是一种非常特殊的情形,了解量子力学的一些基本规律能让我们极大地开阔视野,这是我们这些非专业搞物理的人通过了解量子理论所能得到的最大获益。
- Paul
量子问题虽难但不致于无法理解,否则我们还说这些干嘛捏,量子力学是可以理解的,而且不难理解,我认为仅需基本的逻辑+一点点概率学常识即可。当然,我这样说不是指我们这就可以懂量子力学了,因为归根到底,还是那句--没有人懂量子力学。我说的是,这样我们就可以了解量子原理和我们熟悉的许多知识和规律到底在哪儿不同。这是我的尝试的主要目标。
- Paul
再补充一些量子力学之难造成的悲剧:普朗克,量子理论的创始人之一,发现了普朗克常数(可以说就是量子常数),“1900年,著名教授普朗克和儿子在自己的花园里散步。他神情沮丧,很遗憾地对儿子说:“孩子,十分遗憾,今天有个发现。它和牛顿的发现同样重要。”他提出了量子力学假设及普朗克公式。他沮丧这一发现破坏了他一直崇拜并虔诚地信奉为权威的牛顿的完美理论。他终于宣布取消自己的假设。人类本应因权威而受益,却不料竟因权威而受害,由此使物理学理论停滞了几十年。”
- Paul
更不用提爱因斯坦了。为什么这些那么聪明的人,他们亲手发现了量子论,却拒绝接受它,实在是悲剧啊,这也从另外一个侧面反映了量子论背后引发的对世界本质的思考是多么让人困惑不已。
- Paul
“有生于微”不是我译的,是一本记载惠勒言论的《宇宙逍遥》译者发明的。其实,这有些山寨老子的话:“天下万物生于有,有生于无。”当然,老子的境界更高了。
- Paul
惠勒的语言相当玄妙,和老子几乎同出一辙,黑洞(black hole)这个词就是他的发明,还有The boundary of a boundary is zero. The law without law.
- Paul
事实上,前些年开始有“新道教”的暗流,就把惠勒和汤川秀树(另一位诺贝尔物理奖得主)拉入阵营。
- Paul
Adding the possibility of reply to comments in FriendFeed , in this possibility the user can answer to each comments below it , and there is no need to add any new comment . tough it will become more straight .
- Nimaa
from email
Bad idea imo, a reply to a reply wouldn't appear at the bottom. It would be somewhere in the middle, so you would need to highlight it or something.
- Willem (@wim66) ☠
Well, speaking from experience here on FriendFeed that I have observed, be prepared for 20+ indentations... Plus, as mentioned earlier, the new comments show up at the bottom. This would not be a efficient use of the real time structure if I had to expand comments up and down the list to see new ones.
- Johnny
I agree that this has been implemented in other blogs etc, but they are static, passive entities. A FriendFeed thread ebbs and flows.
- Johnny
Yes,it is all my wish.Chinese guys made a lot of suggestions about the function in Chinese FF feedback two month ago,no answer,no response.
- kelvin
Man, it should be called as "reply", when I saw replay I thought you were talking about the sequence play and put Wave out.
- Burcu Dogan
I can guarantee you that this is not a new idea to the developers here; they have probably had very long and involved conversations about it: how it can be done, how it can be presented, and so forth. And I hope that they've come to the same conclusion that others have: it'd be a bloody mess. The splintering that would occur in a highly active thread would be impossible to keep up with without some mechanisms that would change the entire presentation and style of the site.
- Akiva
I'd love a reply system, definitely but I cannot think of how it would work well in real-time. If we can overcome the issues listed above then great. Either way if we ever get replies I would not put yet about option on the like, share line. Perhaps have it from a dropdown menu on the comment icon, where we could also have 'spam', 'track' and maybe 'abuse' options for each comment.
- Kol Tregaskes
I quite like the flat view for comments & would like it to be possible to switch back & forth if threaded comments happen (perhaps with an @previousposter prepended) I wouldn't be too bothered though, it'd just be nice to still be able to read in order of commenting too ;-)
- immaterial
Feature is similar to Google Wave, was better to executive ;)
- Nimaa
I used to want this, but I think the lack of reply-to-comment helps keep things moving on new content rather than getting bogged down on older stuff (unless it's that picture of the guys licking nipples at the beach, that thing won't die). If you want infinite threading and a bunch of side-tangents, take it to USENET.
- Andy Bakun
Food Network(覆盖英语国家的美食频道)准备推出厨房模拟Wii游戏“炒或被炒(Cook or Be Cooked!)”。与cooking mama之类的轻游戏不同,明星厨师迈克西蒙表示该游戏会非常注重于烹调的拟真,以30个真正的菜谱作为挑战,希望能够使玩家在不受油烟熏烤的前提下真正的玩以致用。【以本宅为Food Network开发某周边的经历看,不觉得他们会认真的把这个东西做好】http://www.wired.com/gamelif...