In a cash transaction valued at approximately $31 million, II-VI Inc. of Saxonburg, Pa., has purchased the equity interests of Marlow Industries Inc. of Dallas, subject to postclosing adjustments. Marlow's thermoelectric products for cooling and power generation are based on semiconductor materials and have applications in such areas as space, photonics, defense, medicine, industry and telecommunications. II-VI intends to expand its offerings to new markets as a result of the acquisition. Marlow will operate within II-VI's Compound Semiconductor Group.