Abstract: This disclosure describes a zinc-free lubricating oil composition. The composition includes a major amount of an oil of lubricating viscosity having a kinematic viscosity at 100° C. in a range of about 1.5 to about 35 mm2/s and an anti-wear mixture having one or more ashless dispersants and an alkyl phosphonic acid having a structure given by wherein R is a C3-C20 hydrocarbyl group. The initial pH of the anti-wear mixture is between 5-9.5 as measured by ASTM D664.

Abstract: Provided is a thermoelectric cooler built-in stem, including a first stem member on a top face of which a temperature controlled target device such as an optical module or the like is mounted, a second stem member which opposes to the first stem member each other, and a thermoelectric cooler being sandwiched between the first stem member and the second stem member, for controlling the temperature controlled target device, whereby a space between the first stem member and the second stem member is filled by an insulating resin whose thermal conductivity is low.

Abstract: Provided is a thermoelectric cooler built-in stem, including a first stem member on a top face of which a temperature controlled target device such as an optical module or the like is mounted, a second stem member which opposes to the first stem member each other, and a thermoelectric cooler being sandwiched between the first stem member and the second stem member, for controlling the temperature controlled target device, whereby a space between the first stem member and the second stem member is filled by an insulating resin whose thermal conductivity is low.