本文转自一亩三分地论坛，作者Dream，转载只为分享给更多的人，感谢原作者的贡献。

　　对于套磁(即与教授，小蜜发邮件联系)，众说纷纭，有的说该套，有的说不用套，这个各人根据自己情况决定，论坛里也有很多相关的帖子，大家去搜索着看看。以下结合自己经历谈些看法。

　　套磁目的是什么?

　　与教授套磁的目的并不是以录取为目标，而是学术交流，教授现在都是很精明的，他们往往鼓励申请，鼓励申请是为了他们自己能够优中选优。往往在收到教授的鼓励申请的邮件，千万不能就此罢了，继续深套;与小蜜套磁的目的是为了最大程度掌握自己能掌握的信息。

　　如何套磁?

　　邮箱选择：个人首先推荐edu邮箱，其次是hotmail、gmail，极其不推荐QQ邮箱、163等。

　　邮件标题：Prospective Ph.D Student Interested in xxx;Prospective Ph.D Student Have Problems about xxx. 这些都一目了然，建议都以Prospective Ph.D Student 开头。如果事情很紧急，你可以在标题中加入Emergency字样，或者直接电话联系。

　　称呼：Hi，Professor! Dear Professor xxx!

　　主体：一句话介绍自己，然后直入主题。

　　结尾： Your early reply will be highlyappreciated!

　　套磁过程：套磁之前至少要浏览教授主页，读读他的文章。读文章，主要是为了你能够与教授有话说，而不是简单地询问招生否等基础问题，向他提出论文中你不懂的东西以及你的一些看法，如果有可能再现教授的实验，指出可以改进的地方等等。教授不回信很正常，做好不回信的准备。如果一个星期之后，还没回，你可以这样发信过去“My email server has been acting up lately, so I'm not sure whethermy previous message was went properly; here it is again just in case. Thanks!”如果没回，我感觉就没有必要再发了。如果你和教授聊的很愉快，那么当你提交申请之后，记得提醒下教授，你提交了申请，让教授注意你的材料。

　　与教授套磁整个过程有了学术上的问题，就大胆去问，大胆去联系。

　　这在我上完GRE强化班的第一封套磁信，那时学术上想深入时，遇到了瓶颈。当时在一个留学讲座上学到了一些怎么套磁的细节问题，邮箱名问题等等，回来后我申请了一个hotmail邮箱，给教授发了信，当时是思量了很久的!

　　人物：MIT教授

　　时间：2009/9/3(当时大三上)

　　主题：Some questions about Ferrofluid

　　Dear professor,

　　I am glad to write this letter to you for some solutions to questions about Ferrofluid!

　　My name is XXX. I am a junior in XXX University of China. My major is Physics.

　　I am interested in Ferrofluid. I fell in love with it at the first spike it makes,so I research its interface instability. Recently, I have some problems about it. I try to solve it, but I did not find the answers. I knew you are areputable expert in this field by surfing the Internet, so I turn to you for some help. The information about the problems is attached to the attachment,which you will see the details.

　　Waiting for your replying at your earliest convenience!Thanks!

　　回信：回答了我的问题并给我传了一些资料，还邀请我参加ICMF12.

　　Dear XXX:

　　Your attachment to me has some beautiful ferrofluid patterns in a spiral cone.

　　The analysis of such a complicated geometry is very difficult andprobably cannot be done in analytical closed form.

　　Most likely it would be necessary to useadvanced numerical solvers of electromagnetic field problems such as AnsoftMaxwell but even then I doubt that you could obtain numerical solutions of theferrofluid peaking shapes.

　　However, Ithink that an adequate understanding of your patterns can be obtained from asimple planar geometry which was first analyzed and published by Cowley and Rosensweig.I attach a copy of theirpaper which I hope you find useful. If you have further questions about this paper please let me know.

　　An excellent reference about Ferrofluids isthe paperback book Ferrohydrodynamics (publsihed by Dover Publications Inc) byRosensweig which is available from Amazon for example for $12.95.

　　The "normal-field instability" isdiscussed in Chapter 7 of the Rosensweig book. You might be interested in visiting MIT OpenCourseware site atocw.mit.edu and to find my graduate course in Electrical Engineering and Computer Science (EECS) 6.642 entitled Continuum Electromechanics.

　　I attach Lecture 8 which discusses themathematics of the ferrofluid normal instability.

　　You might also be interested to attend theInternational Conference of magnetic fluids (ICMF12) in 2010 to be held inSendai, Japan, Aug. 1-5, 2010.You canfind out more information at http://www.senkyo.co.jp/icmf12/.

　　I hope that the above information is usefulto you and that you continue your studies of the science and beauty offerrofluids and perhaps we can meet at ICMF12.

　　Best regards

　　我的回复：

　　Dear professor,

　　Thanks for your earliest replying and youruseful informations! It seems to me that you are also interested in thebeautiful patterns Ferrofluid make in a spiral cone.

　　If you need, I can select some more marvalouspictures to you. Though the analysis is difficult, I will try! I have someplans:1. Read the paper and your lecture note,learn the fundamental equations about Ferrofluid instability, then furtherlylearn the book Rosensweig writed. Try to find some right understandings aboutthe behavior.

　　2. Try to simulate the spike or thebehavior.

　　During the research, I might have somedifficults,I will try to solve by myself first ,then if it do not work ,I willturn to you for some help. I would like to attend the ICMF12. From nowon, I will prepare for the meeting spare no efforts!

　　Thanks again!

　　读完他给的论文，我又进一步和那位教授联系了

　　时间：2009/10/27

　　主题：Some questions about the paper" The interfacial stability of aferromagnetic fluid"

　　Dear professor,

　　How everything goes?I am glad to write thisletter to you for some solutions to questions about the paper"The interfacialstability of a ferromagnetic fluid"!

　　Thepaper inspires me a lot.I get a general understanding of the spike,but therestill exist some confusions.Please see the attachment about my questions,Iprovide two filetype(.doc and .pdf) for you.

　　Waitingfor your replying at your earliest convenience!With best wishes!

　　回信：回答了我的所有问题

　　Dear XXX:

　　1. The phrase stability refers to the factthat with no magnetic field or with a small magnetic field less than M_crit asgiven in eq. 21 or 26 in the Cowley-Rosensweig paper the interface remains flat.This is the stable situation.If the magnetization exceeds M_crit, then theinterface is unstable with a flat interface but reaches a new stableequilibrium with fluid peaks.It is verydifficult to calculate the shapes of the fluid peaks.

　　This would take a nonlinear analysis. One researcher who numerically solves for thepeak shapes is Boudouvis.You should doa literature search for Boudouvis' publications.

　　2. The analysis in the Cowley-Rosensweigpaper is only for first order linear perturbations.The analysis for second order and higher perturbations is non-linear and thus very difficult.I am not aware of any non-linear analysis offerrofluid instability.

　　3. The relationship of b=mu*h is true ineq. 3 for the x and y components. Because the applied DC magnetic field, B_0 and H_0 are z directed and because the magnetization characteric of B(H) is nonlinear, the perturbationfield in the z direction is given by eq. 2 where the slope of B-H characteristic is used rather than the ratio of B/H. I believe that this is correct.

　　4. The usual convention is to write h=- grad(phi) but it is not required.Eq. 4 iscorrect as a definition and I believe that the paper is consistent with thisdefinition throughout the paper.

　　5. The boundary conditions at an interfacewith no surface current, as is the usual case for a ferrofluid/fluid interface,is continuity of tangential H and normal B. The difficulty is that the interfacial deflection has a normal with x,y, and z components.Consistent with alinear analysis that neglects second order and higher terms, the results of eq.7 and the equation between eqs. 5 and 6 are correct.

　　In my Lecture 8 that I sent you in my lastemail to you, please look at page 2 where I derive the normal to the interfacewith a fluid deflection and use the boundary conditions of continuity of normalb and tangential h at the fluid interface. However, my analysis assumes that the magnetic permeability mu isconstant for the ferrofluid rather than being dependent on H as Rosensweig assumes.Our two results should agree ifyou take Rosensweig's mu with a hat over it to equal mu.

　　6. To linear terms so that z_0 is small,perturbation b_z increases with z_0. Ifz_0 gets too large then second and higher order terms become important and eq.13 becomes inaccurate.

　　7. The parameter r is defined just aftereq. 10. If mu with a hat=mu, ther=mu/mu0 as you conclude. The equationthat you quote (where do you get this result from?) is valid if the magnetizationcharacteristic has M varying linearly with H.

　　8. The wavenumber k=2*pi/lambda where thewavelength lambda is the distance between peaks.

　　9. As the magnetic field is increased waybeyond the value for the onset of instability (peaking) the peaks get higher,thinner, and sharper. It is verydifficult to solve for the exact shape as the analysis needs to be nonlinear.

　　10. Since the theory has criticalmagnetization M_crit depending on the fluid density, experiments are done fordifferent fluids with different densities. This allows the theory to be compared with experiments.

　　11. The greater the density of ferrofluid,the greater is the magnetization thereby when comparing theory and experimentyou must account for the change in magnetic permeability.

　　I hope that my answers are helpful toyou. If this is the first time that youare doing this type of linear instability analysis, I suggest that you try to verify my results in Lecture 8 notes, as there I assume that magneticpermeability mu is constant so the analysis is easier.

　　Best of luck

　　我的回复：

　　Dear professor,

　　Thanks for your quick response and your bright answers!

　　The first time I saw the ferroflui, I was impressed by its specialinterfacial instability. At first (during freshman period), I just have aperceptual feeling with that, marveling at its patterns under the magneticfield.As time is going ,I start to study the laws of mathematics behind it.Thismy first time doing the analysis from the point of view of equations.I know Imust learn a lot so as to do a good job.From the paper"Study on Interfacial Phenomena of Magnetic Fluids" (Yoshiyuki FUKUDA and NoriyoshiDOUHARA),I get the other equation about M-crit.

　　I will follow your advice to do my job!

　　Best wishes!

　　在圣诞节的时候，我给教授发去了问候!当时想邮寄纸质的，但没找到英文版的贺卡，就作罢了，发了一个电子贺卡

　　时间：2009/12/24

　　主题：Merry Christmas

　　Dear Professor,

　　On the occasion of the Christmas approaching, I sincerely wish you a happy holiday!The attachment is my gift to you, hoping it can bring you luck andhappiness!

　　Have a nice holiday!

　　结果：没回

　　在老师的指导下，我又接着看教授说的那本书，当时想翻译那本书，于是给教授去了信。

　　时间：2010/1/24

　　主题：About the Book Ferrohydrodynamics

　　Dear professor,

　　In your first E-mail,you recommended me thebook Ferrohudrodynamics. Just asyou said, it is an excellent reference bookabout ferrofluid. My teacher intend to translate it into Chinese andpublish.When contact with the Press in China, they say whether the book isreprinted after 1997. If not,they cann't make it.I don't have ProfessorRosensweig's E-mail,I wonder if you could give us some detail informationsabout the book and the reprintedproblem.By the way,my teacher and I spares noefforts to prepare the papar which will submit to the 12ICMF.

　　With best wishes!

　　他把这封信转给了那个教授，自此和那本书的作者联系了起来。这本书的作者是这个领域的鼻祖式人物。很高兴!

　　和另一个教授的通信(即那本书的作者)：

　　时间：2010/1/24

　　Dear Dr.xxx,

　　Prof. XXX informed me of your interest withyour teacher of translating my book FERROHYDRODYNAMICS into Chinese. Originallythe work was published in hardback in English in 1985 by Cambridge UniversityPress. When that edition went out of print in the mid 1990's I transferred therights to Dover Publications who issued a paperback edition in 1997. Itrecently went out of print. However, Dover presently holds the rights toauthorize a translation of the work. Accordingly, if you wish to proceed youmay contact Dover as follows:

　　Dover Publications, Inc.

　　31 East 2nd Street

　　Minneola, N.Y. 11501 (USA)

　　Telephone (516) 294-7000

　　Fax: (516) 742-5049

　　If you run into difficulties I can in alllikelihood recover the rights and could work with you directly. In the meantimeI would be pleased to learn of your efforts in the study of ferrofluids.

　　Sincerely

　　我的回复：

　　Dear Professor,

　　Thanks for your early reply!

　　First, I want to make it clear that I am aundergraduate student. After disscussion with my teacher, she wants me toconvey the following informations to you:

　　1. We mainly research the preparation, performanceand application of ferrofluid (In 2009, my teacher published a book “Nano-magneticFluid-Preparation, Performance and Application").

　　2. My teacher has been attended the 9th, 10thICMF. This year, we will submit three papers to the 12th ICMF.

　　3. At the beginning of the winter holiday (January10),the translation is going.It will serve as a graduate textbook. Even thoughthe china press cannot publish the Chinese version,we will make it as a letcurenote. However, we really hope it would been reprinted after the 1997edition,thus the press will agree to publish it.

　　由于之前的那位教授邀请我参加ICMF12,于是我们准备投稿，投稿之前给教授两位教授都发了过去，让他们看看。这两位教授在这个领域都很有名望。

　　时间：2010/1/27

　　主题：The paper submit tothe ICMF12

　　Dear Professor,

　　The attachments are my papers, which willsubmit to the ICMF12. Before submission, I send them to for some advice. I domy possible to prepare the papers and really hope it can accept.

　　回复

　　时间：2010/2/14

　　Hello xxx,

　　Here are some comments on the papers thatyou sent to me.

　　1. "A new method...."Your paper shows a new and pleasing methodof displaying ferrofluid and using it to detect the presence of magnetic fieldlines. Just looking at the picture makes me want to hold one of these glassglobes.

　　The methodology itself has been known formany years, see the attachments. The PDF shows packaging that we used in the early1970's at Ferrofluidics Corporation when I was President of the company (formername of Ferrotec Corporation). It featured a square, flat container of the twofluids that was sold commercially. Patterning that could be created using thecell is shown in the illustrations.

　　One of the 'bottle cell' attachments showsan item that is included in an educational kit that is manufactured by FerrotecCorporation and is sold through several other companies currently. The otherbottle cell attachment is a PowerPoint visual that I used in a seminarpresentation a few years ago. The bottle cell is the same one that is includedin the educational kit.

　　Finding a combination of transparent fluidand ferrofluid that resists degradation with time was a challenge.

　　2. Sculpted structure paper. I have seen avery similar U-tube video. Is it your video?

　　If I were on the local committee I wouldrecommend that these two papers be combined into a poster for presentation atthe conference.

　　Sincerely

　　这是在寒假发的，我开学才给回复

　　Dear Professor,

　　Thanks very much for your reading andcomments on my papers!

　　The winter holiday was over and the newterm is coming!

　　The video on the U-tube is not mine. Theattachments are pictures (the video is so large that could not attached) aboutthe second paper and video about the first paper. I have been discussed theresearch about the second paper with MIT professor Markus Zahn (thecommunications will send to you) and try my best to understand it.

　　By the way, I really hope the two could bepublished as papers. But present as poster is also encourage me! Waiting thereply of ICMF12!

　　组委会接受了论文，并且会刊登在一个收录高质量的会议电子杂志(physics procedia)上，一个小遗憾就是由于日方组委会的签证材料来晚了，所以2010年暑假就没去成日本，也就失去了和MIT教授面套的机会。

　　虽然之后忙着出国考试，没怎么和教授交流，但是通过之前的交流，教授已经对我有所了解。上述套磁过程，我一点都没提读书的事，我也向多人咨询过，他们都让我申请时再和教授说读书的事。之后，当我申请时，和教授谈及要做他的研究生，但是他说被MIT很难，虽然如此，我还是申请了，但是被拒了。虽然没有被录取，但是这个套磁过程对我的学术还是有很大帮助的，希望对大家能够有所启发。

　　与小蜜的套磁

　　与系里小蜜套磁或者研究生院小秘套磁都是很重要的，有时候对你掌控自己的申请有很大帮助。

　　一定要向小秘了解以下信息：

　　When the application review process beganand how the process goes?

　　When could I get the admission result?

　　How many international students are yougoing to admit?

　　比如了解到2月中旬出消息，而此时你没有消息，这时，你就应该知道怎么回事了。默拒?还是在Waiting list上?

　　如果很久还没出结果，催催小秘：Sinceit's already March and I haven't heard any words from your university, I'mwriting to check whether a decision has been reached on my application. Pleaselet me know as soon as the result comes out. Thank you very much!

　　关于逃TOEFL和GRE送分费，这个是我本人亲自操作过的，我在补申五所学校的时候，给五所学校都发了这样的信，前提是你手里有ETS寄给你的成绩单：My currentfinancial situation does not permit me to have ETS send you my GRE and TOEFLscore-reports directly; could you consider my application based on copies ofthese reports initially? 其中四个学校同意了，一个学校不同意。当然当时有人提出反对，他说如果你被录取了或者考虑奖学金提名，你又没有成绩单原件，可能会误事，这个大家自己去斟酌吧，自己决定是不是应该这么做。

　　有的学校小蜜超级nice，有的学校则不然，如果邮件不回，打电话过去也是可以的。对于那些非常nice的小蜜，如果你决定去那个学校，非常建议给小蜜带些具有中国特色的礼物，表示谢意!要知道感恩!

　　PhD录取或者没录取，该做些什么?

　　如果学校拒了你，我想应该给学校发邮件，问问为什么没有录取我，找到不录你的真正原因，这个是为了给学弟学妹们好的借鉴，攒攒人品。

　　问MIT的“Dear Professor, I have been checked my application status andfound out that MIT don't offer me the admission. I want to figure out why,could you please help me analyze? Low GPA, GT scores;don't have strongrecommendations;don't come from Peking University?”

　　他们的回答“Dear Sir – Iunderstand your disappointment at not being admitted. This year we received2900+ applications for only 150 openings. We had to turn down many finestudents and I have received many emails similar to yours. The Committee onGraduate Admissions reads all 2900+ applications in a very small window of timeand they do not have time to give explanations that would be useful toyou.By looking at your applicationmyself, I would say that your gradeswere a little low. In order to be admitted an application mustrank in the top5% of the applicant pool andyours did not.”

　　问了MTU，MTU的回信“My GRE score is580(V)+650(Q) Our threshold is: 720and your score is way below +3(AW).What's your threshold value ?”MTU据我的原因是GRE 数学分低。

　　如果给了你录取，但是没有奖，该套谁?

　　如果你想做TA，套Director of Graduate Studies(DGS)，并且说明你有类似的经历，比如期末考试时，义务给大家讲课辅导，或者是进行过类似轮讲的事情，或者是家教之类的事情。

　　如果你想做RA，当然是套各个教授，不是简单去问有没有钱的问题，同样的是表现出对教授某个具体的研究有兴趣，并且提出看法，顺便提想做RA的事。如果给了你奖，这时候，你应该试着套到更多的钱。这是我给VT 套钱的信，发给DGS的，结果被拒绝了：

　　I am very happy that your department cangive me the offer. It means a lot to me.

　　But when I see that your department justpays 82.5% health insurance, I am in a dilemma. For one thing, if I accept youroffer, I am afraid there will be a problem when I apply for the visa, becausemy parents have no savings, as they are both farmers. I also have a sister, who studies at university now. I do not want to increase the burden of my familywhen I go into graduate school. I thought ways to raise funds but failed.

　　For another, if I don't accept your offer, I can choose to go to another universitywhich gives me 100% health insurance. But this school is not my dream school,VT is my dream!

　　So, I am here let you know my currentsuitation and wonder if you could provide me with 100% heatlh insurance orraise my stipend. It is really a hard decision for me to make.

　　主要结构是：

　　这个offer对于我意义重大，非常感谢你们的奖;讲家庭情况以及你自己试着找资助的经历，比如找学校，找相关组织，但都失败了，迫不得已才向你们求助;最后总结。

　　我只是想告诉大家，一件事情，你努力去尝试，即使失败了，你也会学到很多。自己想要的，一定要努力去争取。这让我想起了fight club那部电影里的一个镜头，一个人想进入男主角房子的那场戏，有机会大家可以看看。

　　其他联系：

　　在我申请过程中，要特别感谢Yangyang MM，虽然素不相识，但给了我很多的鼓励与帮助。她指出了我CV中的致命错误，网上的论文作者顺序在与我给出的不一致。当我遇到很大困惑(学校背景，非211，非985;专业背景，物理学师范，半文半理，但我申请了物理，化学，材料，机械等专业;GRE数学偏低。反正感觉就是多处硬伤)时，能够不厌其烦给我解惑，她下面的一席话让我有动力继续完成申请。

　　“前多少名全奖有戏没戏这种问题没有意义，谁都有戏，再怎么伤都有戏，但是谁都没把握，再怎么没伤都没把握。

　　选学校这种事情是要自己做research做，你的专业方向我不会帮你去调查，我自己选的时候是以研究方向为重。排名什么的，除了告诉亲朋好友好听一点，还有什么用呢?这是你为自己将来作的一个过程，你要耐心独立地去完成它，想清楚你想要的是什么，然后去争取。勇敢一点。

　　现在可以做的是完善你的申请材料，没有办法改变的事情就想它了。你是XX大学的学生，的确在这一点上没有优势，但是担心这个没有用，你不会因此不申请，也不能临时换学校，不如把时间心思放在有用的地方。材料差不多就寄了，早交没有坏处，然后该干什么干什么，调整心态等offer。”

（编辑：Ada）