Manual on unit conversion program library UCL2

The unit conversion program library UCL2 has been developed. This library is the expanded and modefied version of UCL1, which was developed for the unit conversion for dynamics and thermodynamics. Using this library, the user can obtain the accurate unit conversion factors between arbitrary units in consistent way. UCL2 has two major functions. The first one is to register the information of dimensions, units and unit systems. This work can be done automatically by the program and/or individually according to the user's selection. The second one is to obtain the unit conversion factor from a certain unit to the unit with same dimension in a certain unit system. Besides, UCL2 has many utility subprograms including character handling programs and unit conversion factor printing-out programs. The application of UCL2 to computer codes will not only improve the accuracy of the codes but prevent careless mistakes in programming about unit conversion. Especially, various correlation programs, the development of which takes a large part of programming work for a large scale computer code, can be developed so that they may be used for any unit system, which will result in the decrease of programming work significantly. Unit conversion factor tables for various physical quantities in dynamics and thermodynamics field were produced from a sample run and are listed in the appendix. (author)