双线斜体小写 D ⅆ

Lowercase 「d」 is often used to denote diameter, distance, differential, and one of the varieties of quarks, as well as other mathematical and scientific phenomena. As for formulas and calculations, the italic 𝑑 , bold small 𝐝 , handwritten 𝒹 from the 字母和数字符号  1D400–1D7FF are used.

Double-struck lowercase 「d」 is rarely seen in scientific works. This unfilled letter with a double outline is commonly used for decorative purposes in texts. Copy and paste it in your nickname or title, on a business card or promotional brochure. This letter combines well with other double-lined symbols from Unicode, such as ⅇ , ⅈ , ⅉ .

符号 「双线斜体小写 D」 包含在 「字母式符号」 块的 「雙擊斜體數學符號」 子块中，并在2002年作为Unicode版本3.2的一部分获得批准。