#460 Update acknowledgement

Author: mitsuaki1987

doc/en/chap06_en.tex

@@ -10,7 +10,8 @@ \chapter{Acknowledgement}
 We would also like to express our thanks for the support of the ``{\it Project for advancement of software usability in materials science}" 
 of The Institute for Solid State Physics, The University of Tokyo, for the development of $\HPhi$ ver. 0.1 - ver. 2.0.
 
-We acknowledged Dr. Yuichi Motoyama and Dr. Yasuyuki Kato for reporting bugs.
+Dr. Yuichi Motoyama and Dr. Yasuyuki Kato found and reported bugs.
+We acknowledge their kindness and carefulness.
 
-We thank Prof. Takeo Hosi and Prof. Tomohiro Sogabe for the fruitful lecture and discussion of the shifted Krylov method and the development of the $K\omega$ library.
+We thank Prof. Takeo Hoshi and Prof. Tomohiro Sogabe for the fruitful discussions on the shifted Krylov method and the development of the $K\omega$ library.