To study properties of the variation of the infrared emission of OH/IR stars. we collect and analyze the infrared observational data in K band for nine OH/IR stars. We use the observational data obtained for about three decades including recent data from the two micron all sky survey (2MASS) and the deep near infrared survey of the southern sky (DENIS). We use Marquardt-Levenberg algo... https://jalyttlers.shop/product-category/dining/