Compositional analysis of dual phase steels by transmission electron microscopy
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size to those reported here) have recently promoted g r e a t i n t e r e s t 2~-25 i s in p h o t o t h e r m a l c o n v e r s i o n of s o l a r e n e r g y . F i l m s , c o a t i n g s , and d e p o s i t s of s e v e r a l m e t a l s h a v e t h e r e q u i r e d c o m b i n a t i o n of h i g h a b s o r b t i v i t y in t h e s o l a r s p e c t r u m , and h i g h r e f l e c t i v i t y (low e m i t t a n c e ) in t h e i n f r a r e d n e e d e d f o r an e f f i c i e n t s o l a r c o l l e c t o r . T h e p a r t i c l e s i z e h a s b e e n found 23,24 to be an i m p o r t a n t p a r a m e t e r in s h a p i n g the s p e c t r a l t r a n s m i t t a n c e of c o l l e c t o r s in o r d e r t o b e s t m a t c h t h e " i d e a l " s t e p f u n c t i o n . T h e p o p u l a r m e t h o d s of d e p o s i t i o n a r e i n e r t g a s e v a p o r a t i o n t e c h n i q u e s , 2 % 26 e l e c t r o p l a t i n g , 25 and v a c u u m s u b l i m a t i o n Y P a r t i c l e s g e n e r a t e d in t h e m a n n e r d e s c r i b e d in t h i s communication may offer some attractive possibilities in s t r u c t u r a l and c o m p o s i t i o n a l c o n t r o l . It h a s b e e n d e m o n s t r a t e d 2,~~ t h a t t h e g a s b r e a k d o w n " t h r e s h o l d p r e s s u r e " i s d e p e n d e n t on t h e p o l a r i z a b i l i t y of the v a p o r s p e c i e s . In e f f e c t f o r a g i v e n p u l s e p o w e r d e n sity breakdown is observed at different minimum gas p r e s s u r e s f o r d i f f e r e n t g a s s p e c i e s . A l s o , the m o l e c u l a r r u p t u r e o c c u r s a t t h e w e a k e s t b o n d in t h e s y s t e m . It s e e m s r e a s o n a b l e , t h e r e f o r e , to e x p e c t t h a t 1) some control over metal particles size would be a c h i e v a b l e t h r o u g h v a r i a t i o n s in v a p o r p r e s s u r e and p o w e r d e n s i t y and 2) in m i x e d v a p o r s y s t e m s s u c h a s t h e m e t a l c a r b o n y l s , w h e r e t h e m e t a l - l i g a n d bond strengths are very similarff some control over metal p a r t i c l e a l l o y i n g w o u l d b e p o s s i b l e by s i m p l e g a s p h a s e c o m p o s i t i o n a l c o n t r o l . It i s i n t r i g u i n g to s p e c u l a t e a b o u t t a y l o r i n g p a r t i c l e s to s p e c i f i c a t i o n s s u c h a s : t o t a l a t o m s - 1 5 0 , 60 p c t F e , 20 p c t M o , 20 p c t W. How one m i g h t s e p a r a t e / p e r f o r m e l e m e n t a l a n a l y s i s on i n d i v i d u a l p a r t i c l e c o m p o s i t i o n vs s o m e a v e r s e comp o s i t i o n of a c o l l e c t i o n of p a r t i c l e s , a l l
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