West Asia Updated 2025-07-16
Baidu Baike Updated 2025-07-16
Ban political donations Updated 2025-07-16
C6 Oxford physics course Updated 2025-07-16
A very honest review of my Oxford University master's degree (theoretical physics at keble college) by alicedoesphysics (2020)
Source. Basically all her courses are from the Mathematical Institute of the University of Oxford, and therefore show up at the Moodle of the Oxford Mathematics Institute of Oxford. Climate change Updated 2025-07-16
Information technology Updated 2025-07-16
Saylor Academy Updated 2025-07-16
This is an interesting initiative which has some similarities to Ciro Santilli's OurBigBook project.
The fatal flaw of the initiative in Ciro Santilli's opinion is the lack of user-generated content. We will never get there without UGC and algorithms, never.
Also as of 2021, it mostly useless business courses: learn.saylor.org unfortunately.
But it has several redeeming factors which Ciro Santilli aproves of:
- exam as a service-like
- they have a GitHub: github.com/saylordotorgo
The founder Michael J. Saylor looks a bit crooked, Rich people who create charitable prizes are often crooked comes to mind. But maybe he's just weird.
Michael Saylor interview by Lex Fridman (2022)
Source. At the timestamp:What statement... maybe he's actually not crooked, maybe it was just an accounting mistake... God, why.
When I go, all my assets will flow into a foundation, and the foundation's mission is to make education free for everybody forever.
If only Ciro Santilli knew how to contact him and convince him that his current approach is innefective and that Ciro has something better! Michael, please Google into this page some day, Ciro Santilli needs funding for OurBigBook.com. A hopeless Tweet at: twitter.com/cirosantilli/status/1548350114623660035. Also tried to hit his
saylor@strategy.com
. Bell's theorem Updated 2025-07-16
Basically a precise statement of "quantum entanglement is spooky".
East Asia Updated 2025-07-16
Larmor frequency Updated 2025-07-16
Research institute model Updated 2025-07-16
Selection rule Updated 2025-07-16
phys.libretexts.org/Courses/University_of_California_Davis/UCD%3A_Physics_9HE_-_Modern_Physics/06%3A_Emission_and_Absorption_of_Photons/6.2%3A_Selection_Rules_and_Transition_Times has some very good mentions:
So it appears that if a hydrogen atom emits a photon, it not only has to transition between two states whose energy difference matches the energy of the photon, but it is restricted in other ways as well, if its mode of radiation is to be dipole. For example, a hydrogen atom in its 3p state must drop to either the n=1 or n=2 energy level, to make the energy available to the photon. The n=2 energy level is 4-fold degenerate, and including the single n=1 state, the atom has five different states to which it can transition. But three of the states in the n=2 energy level have l=1 (the 2p states), so transitioning to these states does not involve a change in the angular momentum quantum number, and the dipole mode is not available.So what's the big deal? Why doesn't the hydrogen atom just use a quadrupole or higher-order mode for this transition? It can, but the characteristic time for the dipole mode is so much shorter than that for the higher-order modes, that by the time the atom gets around to transitioning through a higher-order mode, it has usually already done so via dipole. All of this is statistical, of course, meaning that in a large collection of hydrogen atoms, many different modes of transitions will occur, but the vast majority of these will be dipole.It turns out that examining details of these restrictions introduces a couple more. These come about from the conservation of angular momentum. It turns out that photons have an intrinsic angular momentum (spin) magnitude of , which means whenever a photon (emitted or absorbed) causes a transition in a hydrogen atom, the value of l must change (up or down) by exactly 1. This in turn restricts the changes that can occur to the magnetic quantum number: can change by no more than 1 (it can stay the same). We have dubbed these transition restrictions selection rules, which we summarize as:
Southeast Asia Updated 2025-07-16
ANSI art Updated 2025-07-16
OMG, Ciro Santilli only learned about this in 2021 after: twitter.com/ryancdotorg/status/1375484757916672000
Bicycle Updated 2025-07-16
Big 8 (Usent) Updated 2025-07-16
Big Dipper Updated 2025-07-16
Biochemist Updated 2025-07-16
Nanotechnology Updated 2025-07-16
Romance of the Three Kingdoms (1994 TV series) Updated 2025-07-16
There seems to exist a version with full Chinese + English subtitles: www.youtube.com/watch?v=0_r3eWfTMDs&list=PLdAMXqGeRsOkXzuocRkBPhe5RhZ6RotGH&index=2
www.youtube.com/watch?v=e8VWVvHjskM&list=PLIj4BzSwQ-_ueXTO7EBmShk1b3lEqc5b_ official CCTV电视剧 (CCTV TV Series Channel) upload without Chinese + English subtitles.
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