Does SQL Server have any built-in functions to work with julian dates?

Assuming the Julian date is held as a char
declare @julian char(8)
select @julian='1996.031'
declare @dt datetime

select @dt=DATEADD(dd,convert(int,right(@julian,3))-1,convert(datetime,substring(@julian,1,4)+'0101',212))

select @dt

Julian date in decimal format - e.g. 99123 is 123rd day of 1999 held invariable SDDRQJ.
selectDATEADD(day,CONVERT(int,SDDRQJ)-((1000*(CONVERT(int,SDDRQJ)/1000)))-1,DATEADD(year,CONVERT(int,SDDRQJ/1000),'1 Jan 1900'))