Refractory period (sex) after orgasm in which further sexual stimulation does not produce excitement. While the refractory period varies widely among individuals, ranging from minutes to days, most men cannot achieve or maintain an erection during this time, and many perceive a psychological feeling of satisfaction and are temporarily uninterested in further sexual activity; the penis may be hypersensitive and further sexual stimulation may feel painful during this time frame. An increased infusion of the hormone oxytocin during ejaculation is believed to be chiefly responsible for the male refractory period, and the amount by which oxytocin is increased may affect the length of
Refractory metals cubic except rhenium which is hexagonal close-packed. Most physical properties of the elements in this group vary significantly because they are members of different groups. Creep resistance is a key property of the refractory metals. In metals, the starting of creep correlates with the melting point of the material; the creep in aluminium alloys starts at 200 °C, while for refractory metals temperatures above 1500 °C are necessary. This resistance against deformation at high temperatures makes the refractory metals suitable against strong forces at high temperature, for example in jet engines, or tools used during forging. The refractory metals show