Blog of Brian

This Site Is Now Bilingual (English + Chinese)

Tue, 21 Jul 2026 10:06:38 +0800

Great news: as of today, every piece of content on this site is available in both English and Chinese!

New Home for the Blog: changzh.me + Fully Automated Cloudflare Deployment

Fri, 17 Jul 2026 19:08:03 +0800

Good News: The Blog Has Its Own Domain

Starting today, this blog has a dedicated, easy-to-remember new domain:

https://changzh.me

The old, unwieldy address changzhihang.github.io/blog/ has been intentionally retired — it is no longer maintained and should no longer point to this site. A note of caution: if you ever click a link somewhere and get redirected to that old address, something is misconfigured. Please let me know so I can track it down and fix it. The new domain is not only easier to remember — the entire technical stack behind it has been upgraded. The site now runs on Cloudflare’s global network, loading faster and more reliably, with HTTPS included automatically.

English

Thu, 16 Jul 2026 20:04:00 +0800

A collection of English-learning materials I’ve put together. The current focus is IELTS Speaking: a beginner’s speaking guide plus this season’s full Part 1 question bank with sample answers, built as an interactive web page that expands layer by layer — learn as you click.

🎯 IELTS Speaking Part 1 · Question Bank + Beginner’s Guide

Learn the method and practice the questions on a single page:

📖 Must-read for beginners · IELTS Speaking Guide: the key points and routines for Parts 1/2/3 (the PRE rule, cue-card structure, formulas for developing your ideas), the four scoring dimensions, plus a 4-week practice plan.
🗂️ This season’s 60 topics and 318 questions: filed under five categories — People / Objects / Events / Places / Other.
Three-level click-to-expand: pick a category → click a topic to see all its questions → click a question to see the sample answer (with keywords / high-scoring expressions).

👉 Open: IELTS Speaking Part 1 Question Bank + Beginner’s Guide

Physics

Thu, 16 Jul 2026 14:20:00 +0800

A collection of physics practice problems I’ve put together (advanced level). Each set is an interactive answer-check page: click any sub-question to reveal its answer, click “Show all answers” at the top to expand the whole set at once, and formulas are rendered with MathJax.

⚡ Electromagnetism Comprehensive Practice (Advanced)

Multi-step, cross-topic comprehensive problems, close to the final challenge questions of the college entrance exam / an introduction to competition level. Covers parallel-plate capacitors, motion of charged particles in electromagnetic fields, LC oscillation, electromagnetic induction (rail models), bounded-magnetic-field geometry, and more — including a beyond-syllabus “magnetic field + gravity” challenge.

Bounded Magnetic Field with Gravity: Two Solutions for the "Just-Exits" Condition

Thu, 16 Jul 2026 11:50:00 +0800

A classic high-school physics problem: a charged particle enters a bounded uniform magnetic field perpendicularly, and we ask how strong the field must be so the particle “just exits through the right boundary.” The standard solution ignores gravity, and the trajectory is a clean circular arc. But what happens if gravity is included and the problem is flipped — the field is given, and the width is what we seek? The answer is: the circle becomes a cycloid, and the problem can still be solved elegantly — in two quite different ways. This post documents that extended problem (B6 Extension) and its two solutions.

A Lucky Minecraft Seed I Found: 6927526677832987590

Sun, 12 Jul 2026 00:15:00 +0800

In survival mode, the first few minutes often come down to pure luck. This time, on Java 26.2, I rolled a genuinely incredible seed — 6927526677832987590 — packed with resources, great terrain, and even the speedrunner’s dream combo of a Nether Fortress right at the portal exit plus a Blaze spawner just steps away. Here is a breakdown of the early-game route, both as a personal record and a reference for anyone who wants to recreate it.

From Infinite Subdivision to Rotation Matrices: How I Derived the Equation of Simple Harmonic Motion by Hand

Sat, 11 Jul 2026 11:00:00 +0800

High-school physics tells us that the displacement in simple harmonic motion (SHM) is a sinusoidal function. But textbooks never explain why — they assume a solution of the form $x(t)=\sin(\cdots)$, substitute it into the equation, verify that it works, and call it a day. That is a working backwards from the unknown to the known approach, and it has always left me uneasy.

So I decided to do the opposite: starting from Hooke’s law as the sole axiom, I would analyse the evolution of velocity step by step and see whether I could derive the unknown from the known — letting that sine (or cosine) emerge on its own. This post records my two attempts: the first using brute-force infinite subdivision, the second using matrices and geometry. From complicated to clean, I ended up colliding head-on with Euler’s formula.

Electromagnetism Study Notes: From Electric Fields to Power Generation

Sat, 11 Jul 2026 10:45:00 +0800

I have been systematically studying electromagnetism, tracing the full arc from electric fields, magnetic fields, and circuits through field energy, LC oscillations, and power generation. This post organises those scattered notes into a coherent framework — partly as a personal review, partly in the hope that it helps others working through the same material.

The derivations involve quite a few equations, but the core is really just one thread: electricity and magnetism are two sides of the same coin, and energy flows through the field.

Second Post

Tue, 07 Jul 2026 17:30:07 +0800

This is the second post in this blog.

My Very First Post

Tue, 07 Jul 2026 17:26:07 +0800

This is the first post in this blog.

Written by the creator, Brian Chang.