小卓的壁橱

光本是波，何以有了光线呢？

这是因为把局部的光场近似成了平面波。平面波有两大特点，一是振幅恒定，二是相位梯度恒定。若光场满足振幅近似恒定，相位梯度亦近似恒定，则可把光近似为平面波处理。进一步给这个“近似”下个定义，只要光场的振幅变化速率远小于相位变化速率，相位梯度的变化速率远小于相位的变化速率，光场就可近似为平面光波。

这么说来，通常画光路图的时候人们常常在犯一个小错。通常会作两条或多条光线的交点来求像点，这是有问题的。在像点附近，相位梯度的变化在空间各点变化较大，此时已经不能认为有光线了。像点附近还会发生干涉现象。（rpwang课程笔记整理）

Dear Switch/Count team members,

In this email will be a brief statement of our current situation. It's meant to be a reference that you may want to look at while you are in the lab, as well as a stimulus for discussion while you are absent.

******************************
* where we are are head for
******************************

Our present road map can be summarized as below:

Step 1a. PCR promoter cI434OR21 & cI434OR321 (noted as 434OR), assemble it into the switch plasmid (pSB3K3 from I7100, Kan+).
Product: 434OR on pSB3K3

Step 1b. PCR gene cI, assemble it into the switch plasmid obtained above.
Product: cI_434OR on pSB3K3

Step 2a. PCR gene EGFP, assemble it into the the switch plasmid.
Product: EGFP on pSB3K3

Step 2b. PCR gene cI434, assemble it into the switch plasmid obtained above.
Product: cI434_EGFP on pSB3K3

(Step 1 and 2 will go in parallel.)

Step 3. Cut cI_434OR from the product of Step 1b, assemble it into the product of Step 2b.
Product: cI_434OR_cI434_EGFP on pSB3K3

(In principle, this plasmid potentially has a bistable property. That's our minimum goal.)

Step 4. PCR gene lacIq, assemble it into the product of Step 3.
Product: lacIq_cI_434OR_cI434_EGFP on pSB3K3

(This forms a complete switch plasmid. This is our intermediate goal.)

While Step 1-4 is on its way, we will go in parallel to build up the double repressor plasmid:

Step 1'. PCR cIind-, assemble it into the double repressor plasmid (pSB1A3 from I13521, Amp+).
Product: cIind- on pSB1A3

Step 2'. PCR any one of the double repressor promoter (noted as pDR ), assemble it into the plasmid obtained above.
Product: pDR_cIind- on pSB1A3

(Products of Step 4 and Step 2' form a complete switch system, at least in theory. This is our advanced goal. It would be a miracle if we could do more than that in one week.)

**************************
* where we are
**************************

As till tonight, we have done the following:

* As for PCR, we have successfully obtained the PCR product of 434OR, cI(both SDA & SDC), cI434(both SDcro & SDC) and EGFP(SDY) . They are ready for digestion (some are already digested).
That's all we need for the minimum goal.

* However, the PCR of lacIq and cIind- failed (for twice, once using LA taq, the other case using Ex taq).
The template for lacIq is the genome of some school of bacterial, that for cIind- is pLC003. Both templates are provided by LCB. I suspect there is either a problem with the templates themselves, or with the amount of template I use in the PCR system.

* We have successfully digested pSB1A3 (from I13521) with EcoRI & PstI.

* However, the digestion of pSB3K3 (from I7100) with EcoRI & PstI is problematic . Some plasmids are cut twice (which is good), yet some plasmids are only cut once (which is bad).
CCY will mini-prep pSB3K3 again tonight, followed by a double digestion. Hopefully the digested plasmid will be available for ligation (Step 1a, 2a) tomorrow.

* We have digested the PCR product of 434OR & EGFP with EcoRI & PstI. They are ready for ligation with pSB3K3^^(EcoRI/PstI). Though pSB3K3^^ is problematic (and a good one won't be available till tomorrow morning), CCY will do the ligation tonight.

In short, we are still in Step 1a and 2a. Hopefully we can move to 1b and 2b by tomorrow night (only if the ligation tonight is successful).


Best,
Daizhuo

---

I will write a report of this kind every one or two days & I urge all Switch team members to read it carefully.

It's important that EVERYONE KNOWS WHAT'S HAPPENING IN THE LAB.

Daizhuo

本是约见小小，却升级成了昨晚ioiforum在谷歌中国小聚，还很荣幸的请到了开复老师做东。我和开复只隔一个位置，心想这地儿还不错。哪知，第一圈自我介绍时，便出了小岔子。在座的大多是学计算机的，就我不一样，开复便问我为什么选物理。我近日谦虚惯了，也没多想，只敷衍说是当时北大物院要我啦便去了么云云。开复听了，皱起眉头，脸也沉下来，语重心长道，没主见是不行的。这可好，怎么能让人家这么批评呢？我立马补上说主要是当时北大动手抢得比较快了（这话不假，清华就是慢了一拍所以才没去的）。开复也蛮给面子，接着话头问，“那好，google也来抢你，你来不来？”

我倒是不买账：“Google啊，还不够水准，Princeton抢我我就去。”这也是实话实说。

开复：“Princeton有什么好的？Princeton的博士我们还不一定要呢。”

我：“Princeton的毕业生也不一定想来Google啊。人家研究的研究，赚钱的赚钱，做投行的就比Google赚钱多嘛。”（瞧这话说的…当时随口编的理由）

开复：“你这光想着赚钱，太没有追求了。”

我决定退守：“不是不是，国内的物理还是不错的，华人在物理上颇有建树，几获诺奖，而北大又是国内物理最好，所以才选择北大物理的。”（小注：南大和科大物理系的同学们不要介意，我入学的那阵子还是我们排第一的）

开复：“这个回答还可以，不过这是第二次回答，已经不算数了。”

我：“前面那个joke一下嘛。”

本想这样交锋算是结束，结果才是第一回合。接下来开复不时的提起Princeton，说那儿读博士（大概他指计算机的），要数据没数据，要应用没应用，都是象牙塔里的赘物，全然不如google云云。每每说起，都还要顾左右而言其他的向我这儿瞟几眼。

我心想我读计算机的话倒可能真喜欢google了。难道我读数学物理你也要把我拦着不成？遂好意决定换个话题，把google给网页做检索和大脑对脑中信息的检索做了一个类比，说自己对这个很感兴趣，以后有打算研究这个方向。

开复这回可不客气：“你为什么要浪费青春写几篇没什么人看的论文？有多少人研究过这些事情，你凭什么知道别人做不出来，你就做得出来呢？”

这话说得暗合我意，只是说得太直白太实在了。我想开复也警觉到了这样打击青年学生不好，所以继续说道：“你如果对这个感兴趣，我推荐你一本书，你去好好看看。书的作者是xxx，Palm的前总裁，名字叫…叫…”他一下子没想起来。

碰巧我读过这本书，便顺口讲出名字：“叫On Intelligence是吧？我看过的！”

开复：“是的。”……第二回合结束。

第三回合的起因是大家谈到谷歌近日和本土的天涯网站的合作，是不是在走市民化路线，有损美国总部高端技术的形象。开复先解释一番（我以为还是颇有道理），随后又反问我们，那你们说，中国本土有哪家高端的网站值得尊敬，值得谷歌合作呢？

全桌沉默不语。我想来想去，符合“最值得尊敬”标准的本土网站，也就只有那一家了。

开复把这个问题翻来覆去问了好几次（起码有45s以上），大家眉来眼去，都不说话。最后还是我说的：

“百度啊！”

开复领着全桌一起笑……吃到后来颇有点“耿耿于怀”，开玩笑的对Allen（他的strategy manager，后来入座在我旁边）讲桌上有个崇拜百度的，让Allen教育教育我。那个汗啊…不过平心而论，我以为百度中文搜索的能力还是好过谷歌的。当给百度伸张正义了，哪天李彦宏同学知道了记得报告我！

总而言之，开复是蛮有意思的老板了，我喜欢，哈哈。谷歌大厨的鹅肝也很是好吃，肉质和烤肉筋串有几分相像，改天我也学学。

（谢谢小小的盛情邀请~ 本文玩笑一下，略有夸张大家莫要当真）