When he was conducting his early research 30 years ago, Nobel laureate Herbert A. Hauptman spent long hours at the University of Maryland, much of it in a dilapidated mathematics building. Yesterday, he was back on a much larger College Park campus, no longer as a struggling graduate student, but fresh from receiving the prestigious award for chemistry at ceremonies in Sweden.

Hauptman, 68, was awarded an honorary doctoral degree from the university at winter graduation ceremonies yesterday, 30 years after he earned a doctorate in mathematics from the institution.

"We were proud of him then, and we're proud of him now," said university President John Toll, who had been on Hauptman's doctoral panel. "We welcome Herbert Hauptman back . . . . "

Hauptman, who oversees research at the Medical Foundation of Buffalo, and Jerome Karle, a researcher at the Naval Research Laboratory here, together won the Nobel Prize this fall. Their work -- creating a method to determine the three-dimensional structure of molecules -- was conducted in the early 1950s at the Naval Research Laboratory.

Among those in the audience yesterday was Hauptman's daughter, Carol Fullerton, a doctoral candidate in psychology at the university. Fullerton, 35, said she remembers at the age of 5 watching her father receive his doctoral degree in mathematics.

"I had a sense of what was happening at the time," she said, "but I didn't know the ramifications of what he was doing."

Hauptman's doctoral dissertation, entitled "An n-Dimensional Euclidean Algorithm," stemmed from his work with Karle, for which they won the Nobel Prize. The panel that questioned him on his dissertation included Toll, then chairman of the physics department.

"I got out his dissertation and read it the other day," Toll said before the ceremonies yesterday. "And he did a superb job."

Hauptman clearly remembers Toll's role on the panel: "He asked me the most penetrating questions of all. What it showed me was that he had at least studied it."

Hauptman and his wife Edith lived in the Washington area from the late 1940s until moving to the Buffalo area in 1970. He remembers his years as a graduate student as "very rushed . . . . I was always traveling back and forth" between campus, his Bethesda home and the lab where he worked.

He said he would help his wife mix formula for one of their infant daughters in the evenings, then study until the early hours of the morning.

"He would do his work on the dining room table," his daughter said yesterday. She remembers trying to play a joke on him by adding a minus sign to one of his formulas. "But right away, he knew."

Fullerton said she did not realize until her own college years the importance of her father's work. But she was impressed by that fact Dec. 10, when she witnessed her father receiving his award.

"When my dad stood up . . . I got real tearful. I was just so proud."