function writeHeader() {    // 
document.write('<table border="0" cellspacing="5" cellpadding="0" width="720">');
document.write('<tr>');
document.write('<td colspan="3"><img src="images/spacer.gif" height="20" width="1">');
document.write('</tr>');
document.write('<tr>');
document.write('<td><p><img src="images/spacer.gif" width="150" height="1"></td> ');
document.write('<td valign="middle">');
document.write('<img src="images/maintitle.jpg" alt="Averbukh Group" border="0">');
document.write('</td>');
document.write('<td>');
document.write('<img src="images/spacer.gif" width="20" height="1"><img src="/chemphys/Vega_group/images/semel.jpg" alt="Weizmann Institute Logo " border="0">');
document.write('</tr>');
document.write('<tr>');
document.write('<td colspan="3"><img src="images/spacer.gif" height="15" width="1">');
document.write('</tr>');
document.write('</table>');
}