where the electric displacement field is defined as:
w ɛ ɹ WORD_BOUNDARY ð ɪ WORD_BOUNDARY ɪ l ɛ k t ɹ ɪ k WORD_BOUNDARY d ɪ s p l eɪ s m ə n t WORD_BOUNDARY f iː l d WORD_BOUNDARY ɪ z WORD_BOUNDARY d ɪ f aɪ n d WORD_BOUNDARY æ z WORD_BOUNDARY