"closely attached to" is correct and usable in written English.
You can use it when you are referring to a close connection or relationship between two things. For example: "The two countries are closely attached to each other through strong economic ties."
Back then, hipness was closely attached to bohemia.
Home life sounds classically South Walian: strong, domineering mother, closely attached to her sons; detached father.
"The institution that I feel most closely attached to and most proud of is Americans for Prosperity," Mr. Koch said.
Both parents were loving but austere, and Emily became closely attached to her brother, Austin, and sister, Lavinia.
The tablets, although closely attached to the worship of Baal at his local temple, probably represent Canaanite belief generally.
He remained closely attached to the LSE throughout his life, as a governor for 40 years until 2006, an honorary fellow and chairman of the alumni association.
In addition, it was observed that the PP and the LCP phases closely attach to each other under loading.
Without SERS micropipettes, it is very difficult to obtain the weak Raman signal of A549 cells grew closely attaching to the bottom of the culture dish, even by confocal microscopy.
In order to facilitate antibody penetration of the prominent neural sheath and connective tissue that closely attaches to the CNS of these two species, three to five short pulses in a bath-ultrasonicator (35 kHz, Elma® Transsonic 310) were applied, followed by exposure to a mixture of collagenase and hyaluronidase (Sigma, #C0130 and #H3884, respectively; each at 1 mg/ml in PBS) for 1 h at 37 °C.
They are crowded closely together, attached to the stem (adnate), and usually notched (sinuate).
In this device, a closely fitted piston attached to the end of the lowering cable is installed inside the coring tube.
