我正在使用gfsneohellenicwith包。除了调用或选项mathastext时，大多数功能都运行良好。例如，在下面附加的 MWE 中，有一个奇怪的符号，字母 A 大写，上面有一个半圆，它附加在 g/cm^3 单位后面。siunitxcubedsquared
\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[default]{gfsneohellenic}
\usepackage[italic]{mathastext}
\usepackage{siunitx}
\begin{document}
Even interplanetary space is not entirely empty. But the density of the
matter in it is about \SI{5e-24}{\gram\per\cubic\centi\metre}.
The main component of interplanetary matter is atomic hydrogen. At the
present time, it is considered that cosmic space contains several
hydrogen atoms per \SI{1}{\gram\per\centi\metre\squared}.
\end{document}
如果我使用常规字体，符号就会消失。发生了什么？如何解决？
日志文件提供此列表
*File List*
article.cls 2014/09/29 v1.4h Standard LaTeX document class
size10.clo 2014/09/29 v1.4h Standard LaTeX file (size option)
fontenc.sty
t1enc.def 2017/04/05 v2.0i Standard LaTeX file
gfsneohellenic.sty 2001/12/15 v1.0 Package `gfsneohellenic.sty'
lgrenc.def 2015/12/07 v0.13.1 LGR Greek font encoding definitions
greek-fontenc.def 2015/08/04 v0.13 Common Greek font encoding
definitions
mathastext.sty 2016/11/06 v1.3r Use the text font in math mode (JFB)
siunitx.sty 2017/05/19 v2.7g A comprehensive (SI) units package
expl3.sty 2017/05/13 L3 programming layer (loader)
expl3-code.tex 2017/05/13 L3 programming layer
l3pdfmode.def 2017/03/18 v L3 Experimental driver: PDF mode
xparse.sty 2017/05/13 L3 Experimental document command parser
amstext.sty 2000/06/29 v2.01 AMS text
amsgen.sty 1999/11/30 v2.0 generic functions
array.sty 2016/10/06 v2.4d Tabular extension package (FMi)
l3keys2e.sty 2017/05/13 LaTeX2e option processing using LaTeX3 keys
translator.sty 2010/06/12 ver 1.10
keyval.sty 2014/10/28 v1.15 key=value parser (DPC)
translator-language-mappings.tex
lgrcmr.fd 2016/03/04 v1.1 Greek European Computer Regular
t1neohellenic.fd
translator-basic-dictionary-English.dict
siunitx-abbreviations.cfg 2017/05/19 v2.7g siunitx: Abbreviated
units
omlneohellenic.fd
ot1neohellenic.fd
t1cmtt.fd 2014/09/29 v2.5h Standard LaTeX font definitions
***********
xelatex 的文件输出
*File List*
article.cls 2014/09/29 v1.4h Standard LaTeX document class
size10.clo 2014/09/29 v1.4h Standard LaTeX file (size option)
fontenc.sty
t1enc.def 2017/04/05 v2.0i Standard LaTeX file
t1lmr.fd 2009/10/30 v1.6 Font defs for Latin Modern
gfsneohellenic.sty 2001/12/15 v1.0 Package `gfsneohellenic.sty'
lgrenc.def 2015/12/07 v0.13.1 LGR Greek font encoding definitions
greek-fontenc.def 2015/08/04 v0.13 Common Greek font encoding
definitions
mathastext.sty 2016/11/06 v1.3r Use the text font in math mode (JFB)
siunitx.sty 2017/05/19 v2.7g A comprehensive (SI) units package
expl3.sty 2017/05/13 L3 programming layer (loader)
expl3-code.tex 2017/05/13 L3 programming layer
l3xdvipdfmx.def
xparse.sty 2017/05/13 L3 Experimental document command parser
amstext.sty 2000/06/29 v2.01 AMS text
amsgen.sty 1999/11/30 v2.0 generic functions
array.sty 2016/10/06 v2.4d Tabular extension package (FMi)
l3keys2e.sty 2017/05/13 LaTeX2e option processing using LaTeX3 keys
translator.sty 2010/06/12 ver 1.10
keyval.sty 2014/10/28 v1.15 key=value parser (DPC)
translator-language-mappings.tex
lgrcmr.fd 2016/03/04 v1.1 Greek European Computer Regular
t1neohellenic.fd
translator-basic-dictionary-English.dict
siunitx-abbreviations.cfg 2017/05/19 v2.7g siunitx: Abbreviated
units
omlneohellenic.fd
ot1neohellenic.fd
t1lmtt.fd 2009/10/30 v1.6 Font defs for Latin Modern
***********
更新：我升级到了 MacTeX 2018，但问题仍然存在。以下是 2018 编译的文件列表
*File List*
article.cls 2014/09/29 v1.4h Standard LaTeX document class
size10.clo 2014/09/29 v1.4h Standard LaTeX file (size option)
fontenc.sty
t1enc.def 2017/04/05 v2.0i Standard LaTeX file
t1lmr.fd 2009/10/30 v1.6 Font defs for Latin Modern
gfsneohellenic.sty 2001/12/15 v1.0 Package `gfsneohellenic.sty'
lgrenc.def 2015/12/07 v0.13.1 LGR Greek font encoding definitions
greek-fontenc.def 2015/08/04 v0.13 Common Greek font encoding
definitions
mathastext.sty 2016/11/06 v1.3r Use the text font in math mode (JFB)
siunitx.sty 2018-03-20 v2.7m A comprehensive (SI) units package
expl3.sty 2018/03/05 L3 programming layer (loader)
expl3-code.tex 2018/03/05 L3 programming layer
l3xdvipdfmx.def
xparse.sty 2018/02/21 L3 Experimental document command parser
amstext.sty 2000/06/29 v2.01 AMS text
amsgen.sty 1999/11/30 v2.0 generic functions
array.sty 2018/04/07 v2.4g Tabular extension package (FMi)
l3keys2e.sty 2018/02/21 LaTeX2e option processing using LaTeX3 keys
translator.sty 2018/01/04 v1.12 Easy translation of strings in LaTeX
keyval.sty 2014/10/28 v1.15 key=value parser (DPC)
lgrcmr.fd 2017/07/29 v1.2 Greek European Computer Regular
t1neohellenic.fd
translator-basic-dictionary-English.dict
siunitx-abbreviations.cfg 2017/11/26 v2.7k siunitx: Abbreviated units
omlneohellenic.fd
ot1neohellenic.fd
t1lmtt.fd 2009/10/30 v1.6 Font defs for Latin Modern
***********
更新：解决了！按照 jfbu 的建议，我将 MWE 的内容从此处复制粘贴回 texshop，问题解决了。我从一个 pdf 中复制粘贴了原始文本，该 pdf 在这两个条目的末尾有一个额外的字符。不知何故，texshop 没有显示这些，但将其粘贴到纯文本编辑器中时，这两个额外的字符显示为块。
答案1
事实证明，OP 在所使用的文本编辑器中遇到了一些编码问题，并且无论使用哪个版本的软件包，都无法通过复制粘贴发布的 MWE 来重现该问题。