By 1963, Kroll, together with his graduate students, did research on the De Haas-Van Alphen effect of bound electrons and used the expression for the magnetic permeability by spreading the lattice's potential energy in a Fourier series.Wolfgang Kroll; Kai-Yuan Chung. The van Alphan-de Haas Effect for Bound Electrons. Chinese Journal of Physics. October 1963, He also worked with his students to study the solution of the electromagnetic wave equation of a waveguide with internal wrinkles and to find its waveguide coefficient, and his results were published in the Journal of Physics of the Republic of China from 1963 to 1967.Wolfgang Kroll. The iris-loaded wave guide is a boundary value problem. Chinese Journal of Physics. October 1964,Wolfgang Kroll. The iris-loaded waveguide as a boundary value problem. II. Chinese Journal of Physics. April 1965Wolfgang Kroll. The iris-loaded wave guide as a boundary value problem. III. Chinese Journal of Physics. October 1965, Later, in 1967, Kroll also published a paper on the development of function classes satisfying a particular integral formula in the same journal 1967.Wolfgang Kroll. Series-Expansions for Functions Satisfying Some Integral-Equations. Chinese Journal of Physics. October 1967, Students taught by Kroll said that he was also interested in electromagnetic differential equations with different boundary conditions and that Bessel functions were like "old friends to him". By 1972, Kroll was mainly devoted to problems related to elasticity theory. Influenced by the training he received in his early years, his research is more in the area of mathematical computation.
