删除右上角的页码；保留底部中央的页码

Question

论文的要求让我头疼不已！我终于搞定了一切，只剩下一个问题：我需要删除从第 1 章开始页面右上角的阿拉伯页码。

以下是相关代码（最底部是问题所在——最后三行）：

\pagestyle{empty}
\pagenumbering{roman}

% A B S T R A C T
% ---------------
\addcontentsline{toc}{chapter}{Abstract}
\begin{center}\textbf{ABSTRACT}\end{center}

\input{Abstract.tex} 

\clearpage

\pagestyle{fancy}
\setcounter{page}{4}
\fancyhf{}
\fancyhead[R]{\thepage}
\renewcommand{\headrulewidth}{0pt}

% S T A T E M E N T  OF  C O N T R I B U T I O N S  P A G E
% -------------------------------
 \noindent
 \addcontentsline{toc}{chapter}{Contributions} 
 \begin{center}
 \textbf{STATEMENT OF CONTRIBUTIONS}
 \end{center}
 \bigskip 
 \noindent
\input{contributions.tex} 

\clearpage

% D E D I C A T I O N
% -------------------

\begin{center}\textbf{DEDICATION}\end{center}

\begin{center}
Dedication
\end{center}

\newpage

% A C K N O W L E D G E M E N T S
% -------------------------------

\addcontentsline{toc}{chapter}{Acknowledgements}
\begin{center}\textbf{ACKNOWLEDGEMENTS}\end{center}

%Acknowledgements will go here.

\clearpage


% C O M I C
% ---------
\addcontentsline{toc}{chapter}{Comic}
\begin{center}

\vspace*{0.75cm}
\includegraphics[scale=0.75]{machine_learning_xkcd_1838.png} 
\\
\vspace*{0.5cm}
Reprinted from \href{http://xkcd.com/1838}{xkcd.com}. 
\end{center}

\newpage

% T A B L E   O F   C O N T E N T S
% ---------------------------------

\fancypagestyle{plain}{% 
\fancyhead[RO]{\thepage} 
}

\renewcommand\contentsname{\hfill\normalsize\textbf{CONTENTS}\hfill}

\tableofcontents

\newpage 

% L I S T   O F   T A B L E S
% ---------------------------
\makeatletter
\renewcommand\listoftables{%
    \@starttoc{lot}%
    }
\makeatother
\begin{center}\textbf{LIST OF TABLES}\end{center}
\addcontentsline{toc}{chapter}{List of Tables}

\begin{center}
\listoftables
\end{center}

\phantomsection     % allows hyperref to link to the correct page

\newpage %Sept 24

% L I S T   O F   F I G U R E S
% -----------------------------
\makeatletter
\renewcommand\listoffigures{%
    \@starttoc{lof}%
    }
\makeatother
\begin{center}\textbf{LIST OF FIGURES}\end{center}
\addcontentsline{toc}{chapter}{List of Figures}

\begin{center}
\listoffigures
\end{center}

\phantomsection     % allows hyperref to link to the correct page
\newpage

% P R E F A C E
% -------------
\addcontentsline{toc}{chapter}{\textbf{Preface}}
\begin{center}
\textbf{{PREFACE}}
\end{center}
\input{preface.tex}  
\pagestyle{plain}
\cleardoublepage

% Change page numbering back to Arabic numerals

\fancyhr{}
\pagenumbering{arabic}
\cfoot{\thepage}

我怎样才能隐藏右上角的页码？