fix single author problem

application/default/views/scripts/knowledge/paper.phtml

@@ -20,7 +20,7 @@ $this->headLink()->appendStylesheet('/css/colorbox.css');
         	<h3><?php echo $this->paper['title']; ?></h3>
         	<hr />
         <?php } ?>
-        <?php if(count($this->author) > 0) {?>
+        <?php if($this->author) : ?>
         <h4>作者</h4>
 		<ul>
 			<?php foreach($this->author as $a) : ?>
@@ -28,7 +28,7 @@ $this->headLink()->appendStylesheet('/css/colorbox.css');
             <?php endforeach; ?>
 		</ul>
         <hr />
-        <?php } ?>
+        <?php endif; ?>
         
 		<?php if ($this->paper['abstract']){ ?>
 			<h4>摘要</h4>