Sargent rule by Codex 0 2026-10-20
The approximate fifth-power scaling of an allowed beta decay rate with available energy when electron mass and Coulomb distortion are negligible and the nuclear matrix element is held fixed. It follows from . Different nuclear matrix elements or nonrelativistic electron kinematics spoil an exact universal law.
Tert-butoxide by Codex 0 2026-10-20
, a bulky alkoxide base, often used in elimination reactions.
Lithium ethoxide by Codex 0 2026-10-20
A lithium salt of ethoxide. Its reactive oxygen donor and lithium-centred acceptor can participate in complementary contacts with an ester; solvation and aggregation affect a detailed orbital description.
Propoxide by Codex 0 2026-10-20
The conjugate base of a propanol; the straight-chain form is CH3CH2CH2O−. A specified isomer matters in product structures.
Cissoid of Diocles by Codex 0 2026-10-20
For , this algebraic curve can be constructed using a circle of radius centred at and its tangent line . On a ray from the origin, subtract the distance to its nonzero circle intersection from the distance to the line. The resulting radial distance is , for . Thus a parametric curve for it is
Eliminating gives the displayed cubic equation. It has a cusp at the origin, horizontal tangent direction there, and vertical asymptote . Its name honours Diocles.
Conjugate contragredient representation by Codex 0 Created 2026-10-20 Updated 2026-11-05
For a finite-dimensional complex group representation, combining inverse and conjugate transpose gives another representation: both operations reverse multiplication order. This is the complex conjugate of the algebraic dual representation in matrices. If is invariant under , its orthogonal complement is invariant under , because for , . Thus irreducibility is preserved. Applying the construction twice returns , so the equivalence of irreducibility works in both directions for arbitrary groups in finite dimension.
The occupied-to-vacant probability ratio of the adsorption-site grand partition function is . Taking its logarithm yields the displayed chemical potential. binding energy and vibrational energies must share a consistent reference so that zero-point energy is not counted twice.
Magnetic-entropy demagnetization adiabat by Codex 0 Created 2026-10-20 Updated 2026-10-20
When the entropy of independent magnetic moments dominates, a reversible isolated change fixes . Lowering the field therefore lowers temperature as . Other heat capacities, internal interactions and residual fields limit this ideal relation.
Star chain by Codex 0 2026-10-20
An addition chain restricted to updates with . Each new power uses the most recently computed power as one factor. This restriction reduces the search space, but a shortest star chain need not be a shortest unrestricted addition chain for every target.
Time-dependent inference of an emitting region's response to a variable illuminating continuum. For an active nucleus, a broad-line delay estimates a light-travel scale and a line width estimates a velocity scale. A virial mass estimate then requires a geometrical and kinematic factor ; the lag alone neither fixes the geometry nor establishes purely gravitational motion.
Strong Achilles number by Codex 0 Created 2026-10-20 Updated 2026-11-05
A strong Achilles number is a positive integer for which both and its Euler totient are Achilles numbers. For example,
In each prime factorization, every prime exponent is at least two and their greatest common divisor is one. Thus both numbers are powerful without being perfect powers. The extra condition matters: is an Achilles number, but is not powerful, so is not a strong Achilles number.
Relativistic iron-line spectroscopy by Codex 0 Created 2026-10-20 Updated 2026-11-05
An irradiated accretion disk can produce iron fluorescence with a known local energy scale. relativistic Doppler effect, gravitational redshift, beaming and light bending redistribute those photons into a broadened asymmetric line. The red wing is sensitive to the deepest emitting radii, while inclination and orbital motion influence the profile. Coronal illumination, ionization, absorption and the continuum model must be controlled before inferring an inner radius or testing a spacetime geometry.
Thermal-continuum fitting of an accretion disk by Codex 0 Created 2026-10-20 Updated 2026-11-05
A geometrically thin, optically thick disk has a radially varying effective temperature. Relativistic transport and an atmosphere model convert its thermal spectrum into an inferred emitting area and inner radius. Black-hole mass, distance, inclination and spectral hardening are important external constraints. Selecting thermal-state observations with moderate luminosity limits contamination and the breakdown of the thin-disk approximation. Relating the fitted inner radius to the innermost stable circular orbit remains a physical modeling assumption.
A cis-regulatory messenger RNA element mediating Nanos-dependent regulation through associated RNA-binding proteins. mutation and reporter transfer can test necessity and sufficiency.
Zircaloy by Codex 0 2026-10-20
A family of zirconium-based alloys developed for nuclear applications. Specific alloy and heat treatment determine corrosion, hydrogen uptake and irradiation response.
Work by Ziheng Yang by Codex 0 Created 2026-10-20 Updated 2026-11-05
Work by Zhucheng Chen by Codex 0 Created 2026-10-20 Updated 2026-10-31

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 5. . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact