jQuery UI某些函数错误TypeError：$（...）。accordion不是函数

我尝试遵循stackoverflow中的另一个问线程，但没有任何结果，但我收到错误TypeError：$（...）。accordion不是使用手风琴函数时的函数，但对于其他函数JQuery UI（例如“ effect”），它的效果很好。

这是我的代码

<h3>Our Product</h3>
<div id="accordion">
  <div id="accordion">
  <h3>Section 1</h3>
  <div>
    <p>Mauris mauris ante, blandit et, ultrices a, susceros. Nam mi. Proin viverra leo ut odio. Curabitur malesuada. Vestibulum a velit eu ante scelerisque vulputate.</p>
  </div>
  <h3>Section 2</h3>
  <div>
    <p>Sed non urna. Donec et ante. Phasellus eu ligula. Vestibulum sit amet purus. Vivamus hendrerit, dolor at aliquet laoreet, mauris turpis porttitor velit, faucibus interdum tellus libero ac justo. Vivamus non quam. In suscipit faucibus urna. </p>
  </div>
  <h3>Section 3</h3>
  <div>
    <p>Nam enim risus, molestie et, porta ac, aliquam ac, risus. Quisque lobortis. Phasellus pellentesque purus in massa. Aenean in pede. Phasellus ac libero ac tellus pellentesque semper. Sed ac felis. Sed commodo, magna quis lacinia ornare, quam ante aliquam nisi, eu iaculis leo purus venenatis dui. </p>
    <ul>
      <li>List item</li>
      <li>List item</li>
      <li>List item</li>
      <li>List item</li>
      <li>List item</li>
      <li>List item</li>
      <li>List item</li>
    </ul>
  </div>
</div>
</div>
</div>

在我的head.php文件中，jquery和jquery ui均加载成功

<title><?php echo $title;?> | Mitra Dekor</title>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="description" content="">
<meta name="keywords" content="">
<meta name="author" content="">
<link rel="stylesheet" href="<?php echo base_url('assets/css');?>/bootstrap.css" type="text/css">
<link rel="stylesheet" href="<?php echo base_url('assets/css');?>/font-awesome.css" type="text/css">
<link rel="stylesheet" href="<?php echo base_url('assets/css');?>/owl_003.css" type="text/css">
<link rel="stylesheet" href="<?php echo base_url('assets/css');?>/owl.css" type="text/css">
<link rel="stylesheet" href="<?php echo base_url('assets/css');?>/owl_002.css" type="text/css">
<link rel="stylesheet" href="<?php echo base_url('assets/css');?>/fonts.css" type="text/css">
<link rel="stylesheet" href="<?php echo base_url('assets/css');?>/mitradekor.css" type="text/css">
<link rel="stylesheet" href="<?php echo base_url('assets/css/jquery-ui');?>/jquery-ui.css" type="text/css">
<link rel="stylesheet" href="<?php echo base_url('assets/css');?>/tooltipster.css" type="text/css">
<link rel="stylesheet" href="<?php echo base_url('assets/css/themes');?>/tooltipster-light.css" type="text/css">
<script src="<?php echo base_url('assets/js');?>/jquery-1.9.1.min.js" type="text/javascript"></script>
<script src="<?php echo base_url('assets/js');?>/jquery-ui.js" type="text/javascript"></script>

<script src="<?php echo base_url('assets/js');?>/jquery.contenthover.min.js" type="text/javascript"></script>

这是我的js代码，我使用外部文件并将其放在页脚中

$( function () {
$(".owl-carousel").each(function() {
$(this).owlCarousel({
  items: 10,
  singleItem: true,
  autoPlay: true,
  stopOnHover: true,
  transitionStyle: true
 });
});

 **$( "#accordion" ).accordion({
  heightStyle: "content"
 });**
 });

我的代码有问题吗？

更新这是jsfidlle http://jsfiddle.net/a0jzt46p/

谢谢