Quite a beautiful bloom. C. dowiana's genes do some really great things in its hybrids. Too bad about the short flower life, but like Steve said, that might improve as the plant matures. Congrats on your great blooms.
Thank you all . I thought the blooming was short because 1 flower dropped after opening a few days (it had a twisted stem). However, the other one keeps staying there and continue to intoxicate my working desk with very strong fragrance.