[學術研究] 碩士班時期的紙本研究筆記及數據圖
2020-03-01星期日，獻慶整理房間、清出一堆碩士班時期的紙本研究筆記及數據圖。
哇! 竟然一放就是15年...
房間空間不足，快來電子化吧...
紙張量太多，掃描不易
其實掃描筆記這檔事，獻慶十年前就想幹了，只是設備的效率太差，才一直擱置這件事。
快1000頁的文件，一張一張掃描，太耗時間了。
好在現在的機台可以進行批次掃描，效率就快了很多。才能將這十年前的 "殘念"解決。
^_^
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| 碩士班時期的紙本研究筆記及數據圖。有12公分厚! |
掃描到一半，突然間卡紙了。
經過清查，發現有塑膠物品，冏...
原來是一張塑膠投影片黏在紙張上面造成。
當年這樣做，是為了要把資料庫中的x-ray譜線跟樣本的x-ray譜線進行比對。
故障排除後，繼續掃描。
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| x-ray譜線疊合比較。 |
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| 上面的塑膠投影片上面印的是資料庫中的x-ray譜線，下面的白紙印的是實驗樣本的x-ray譜線。這樣很方便比對譜線的位置及強度。 |
碩士時期的研究工作
筆記的內容，雜七雜八。
有樣本製作及x-ray圖、M-H、R-H、R-T、M-T、X-T... 一堆數據圖。看到眼花撩亂了。
以下，給出些代表性的數字好了。
當時，磁場有做到14 T、溫度有做到3 K (−270℃)、真空度有抽到10-6 torr。
冏事一籮筐
老鼠事件
2006年，那年農曆過年，也許是大家回去過年，沒人餵飽老鼠。
於是老鼠就跑去機台裡面取暖，窩住了，除了在主機板上大小便外，還把很多訊號線給咬了，冏...
600萬的儀器就GG惹...
所以... 老鼠平常要餵飽?! 😂
Helium Quench (Magnet Quench)
當磁場要由6 T升高至8 T時，可能是由於磁場上升過快，造成超導線圈無法保持住超導態，放出大量的熱，把液態氦直接氣化...
結果...
結果就是"碰"一聲巨響，一瞬間、卸壓閥的塞子像子彈般直接往天花板打去，接著噴出一堆白煙。
這絕對不是好玩的，根據儀器手冊上面的"警告"，就是有三角形、裡面有驚嘆號那種。要快點離開試驗室，否則會有窒息的危險(大量的氦氣把氧氣推走了)。
當時，研究室整群人，都撤出了...
冏!
事後回來評估損失，超導磁鐵跟實驗儀器可能有些微損傷。
1桶100公升的液氦要4萬元，在不到1分鐘的時間噴發掉一半以上... 😂
總之人平安就好了!
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| Helium quench (Magnet quench)意外紀錄。 |
參考資料:
YouTube: 9 Tesla Superconducting Magnet Quench | $500 Of Helium Lost In Under 1 Minute
https://www.youtube.com/watch?v=SRdBQz36_24
他對Helium quench的講解很確實。另外，1分鐘內噴掉500美金，很合理的評估。
YouTube: MRI magnet quench: the movie
https://www.youtube.com/watch?v=9SOUJP5dFEg
這是我第一次看到這麼歡樂的Helium quench，大家玩得很開心。當然，他們是做足的準備才敢這樣幹。
新聞: 百萬網紅開生日趴「30公斤乾冰倒泳池」變毒氣室 三人穿防護衣慘死⋯老公也走了
與Helium quench相同的概念，短時間內、再封閉空間中的非氧氣體，會將氧氣排出，造成人員傷亡、甚至窒息。
固體二氧化碳（乾冰）倒入泳池後，產生的氣體二氧化碳會排擠掉空間的氧氣，水中也會出現大量氣泡，現場彷彿成為了無氧的毒氣室。最後包括瓦倫廷在內，總共造成3人死亡，4人受傷的慘劇。
迪科登和老公都擁有理工背景的高學歷，加上兩人過去也曾在IG做過二氧化碳實驗，因此不可能不知道將二氧化碳倒入水中是危險的舉動，所以賓客們才會穿上防護衣。只是一切還是太過輕率，最終仍釀成悲劇。
感想
以現在的角度去看當年，很多實驗真的是"傻傻地做"，冏事也是一籮筐。傻歸傻，也好在當年一步一腳印、認真做實驗，累積了很多數據及經驗，才能完成碩士論文。
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| 鍾獻慶碩士論文。 |
感謝
感謝註福印刷企業社鍾和翰總經理將該紙本掃描成圖檔。
950張，不到1小時掃完，爽!
這是獻慶十年前就想幹的事，只是那時候獻慶的掃描器，只能掃單張，而且掃描速度還很慢。如果以一張五分鐘的速度來算，大約要80小時不眠不休才能完成。
完成十年前的願望，GOOD! ^_^
(FB link: https://www.facebook.com/hsienching.chung/posts/3158105460869068 )
相關連結
Magnet Quench
Quenching is the process whereby there is a sudden loss of absolute zero of temperature in the magnet coils, so that they cease to be super conducting and become resistive, thus eliminating the magnetic field. This results in helium escaping from the cryogen bath extremely rapidly. It may happen accidentally or can be manually instigated in the case of an emergency.
Quenching may cause severe and irreparable damage to the super conducting coils, and so a manual quench should only be performed in extreme cases when the physician and service engineer are involved in the decision to quench. A fire in the scan room may also be a cause to quench the magnet, so the firefighting personnel can safely enter the room (see MRI Code Red Protocol). All systems should have helium-venting equipment, which removes the helium to the outside environment in the event of a quench. However if this fails, helium will vent into the room and replace the oxygen. For this reason all scan rooms should contain an oxygen monitor that sounds an alarm if the oxygen falls below a certain level. Under these circumstances immediate evacuation of the patient and personnel is necessary.
If the scan room door is closed when a quench occurs and helium escapes into the scan room, the depletion of oxygen causes a critical increase in pressure in the room compared with the control area. This produces high pressure in the scan room, which may prevent opening of the door. If this should happen, the glass partition between the scan and control rooms should be broken to release the pressure. The scan room door can then be opened as usual and the patient evacuated. In such a case the patient should be immediately evacuated and evaluated for asphyxia, hypothermia and ruptured eardrums.
Ref: https://radiology.ucsf.edu/patient-care/patient-safety/mri/quench
A quench is an abnormal termination of magnet operation that occurs when part of the superconducting coil enters the normal (resistive) state. This can occur because the field inside the magnet is too large, the rate of change of field is too large (causing eddy currents and resultant heating in the copper support matrix), or a combination of the two. More rarely a defect in the magnet can cause a quench. When this happens, that particular spot is subject to rapid Joule heating from the enormous current, which raises the temperature of the surrounding regions. This pushes those regions into the normal state as well, which leads to more heating in a chain reaction. The entire magnet rapidly becomes normal (this can take several seconds, depending on the size of the superconducting coil). This is accompanied by a loud bang as the energy in the magnetic field is converted to heat, and rapid boil-off of the cryogenic fluid. The abrupt decrease of current can result in kilovolt inductive voltage spikes and arcing. Permanent damage to the magnet is rare, but components can be damaged by localized heating, high voltages, or large mechanical forces. In practice, magnets usually have safety devices to stop or limit the current when the beginning of a quench is detected. If a large magnet undergoes a quench, the inert vapor formed by the evaporating cryogenic fluid can present a significant asphyxiation hazard to operators by displacing breathable air.
GOOD! ^_^
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