## Immune System 免疫系统

The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinters, distinguishing them from the organism’s own healthy tissue. Many species have two major subsystems of ...

## Respiratory System 呼吸系统

The respiratory system is the organs and other parts of your body involved in breathing, when you exchange oxygen and carbon dioxide. Parts of the Respiratory System Nose and nasal cavity Sinuses Mouth Throat (pharynx) Voice box (larynx) Windpipe (trachea) Diaphragm Lungs Bronchial tubes/bronchi Bronchioles Air sacs (alv...

## Photonic Quantum 光量子

A photonic quantum computer could have huge advantages over its matter-based counterpart. Photons are much less prone to interact with their environment, which means they can retain their quantum state for much longer and over long distances. A photonic quantum computer could, in theory, operate at room temperature – and as a result, scale up mu...

## Five Elements 五行元素

Chinese people believe that we are surrounded by five energy fields or five different kinds of “Qì” (气). These are also called the “five elements” and they play an important role in all aspects of Chinese culture, including the way people eat. This theory states that if these five elements are changed or moved, this could seriously affect a pers...

## Predict Failure 预测失效

Maximum Normal Stress Criterion The maximum stress criterion, also known as the normal stress, Coulomb, or Rankine criterion, is often used to predict the failure of brittle materials. The maximum stress criterion states that failure occurs when the maximum (normal) principal stress reaches either the uniaxial tension strength st, or the uniaxi...

## Riemann Hypothesis 黎曼猜想

Riemann hypothesis, in number theory, hypothesis by German mathematician Bernhard Riemann concerning the location of solutions to the Riemann zeta function, which is connected to the prime number theorem and has important implications for the distribution of prime numbers. Riemann included the hypothesis in a paper, “Ueber die Anzahl der Primzah...

Divergence Divergence is an operation on a vector field that tells us how the field behaves toward or away from a point. Locally, the divergence of a vector field $\vec{F}$ in $\mathbb{R}^2$ or $\mathbb{R}^3$ at a particular point $P$ is a measure of the “outflowing-ness” of the vector field at $P$. If $\vec{F}$ represents the velocity of a flu...