Microsoft Word - Editorial.doc Editorial It is our pleasure to present a new volume of BIBECHANA (volume 7) where we have interesting and educational research articles in physics, chemistry, biology, mathematics and related disciplines. It is believed that BIBECHANA will provide major contributions to the field of science, technology and mathematics. We have had an excellent response from authors and readers. It is a very exciting experience to get an overwhelming response from scholars and colleagues. With this volume online version of BIBECHANA will also be published in the homepage http://www.nepjol.info/index.php/BIBICHANA . This will help us expand our presence in superior community of educationists, scientists and technologists. At this point, we sincerely thank Mrs. Sioux Cumming for her cooperation. Finally, we would like to thank all contributors who have supported this journal specially authors, referees and readers. Devendra Adhikari Editor- in- Chief