Under scanning electronic microscope, four kinds of metal structure may be observed including black core phase, white core phase, gray ring phase and white adhesion phase.

在扫描电子显微镜下可观察到四种金相组织：黑色芯相、白色芯相、灰色环形相和白色粘结相。

youdao

That, for me, sums up the seductive intellectual core of computers and computer programming: here is a magic black box.

这对我来说，构成了有吸引力的计算机和计算机语言的核心：这是一个黑色的魔法盒子。

youdao

He sits on a chair in a windowless laboratory and cradles a large rock, or core, of jet-black flint in his left hand.

桑德加特坐在一间无窗户的实验室里的一张椅子上，他的左手握着一块墨黑的大燧石。

youdao

Because the metro area's population is 26% black, the whiter counties have long avoided anything that might bring them any closer to the black core.

ECONOMIST: Urban sprawl

Our own galaxy, the Milky Way, has a colossal black hole at its core, too, which is some three million times the mass of our Sun.

BBC: NEWS | Science/Nature | Deepest X-rays tell merger story

The DA has been through numerous re-branding exercises since its origins in the anti-apartheid movement of the 1970s and 80s, but in the eyes of some people it remains a "white" party, led by a white woman, Helen Zille, and somehow out of touch with the core values of black South Africans.

BBC: Is the ANC losing its grip on South Africa?