Contact angle a contact angle of 0°. This is often the case for water on bare metallic or ceramic surfaces, although the presence of an oxide layer or contaminants on the solid surface can significantly increase the contact angle. Generally, if the water contact angle is smaller than 90°, the solid surface is considered hydrophilic and if the water contact angle is larger than 90°, the solid surface is considered hydrophobic. Many polymers exhibit hydrophobic surfaces. Highly hydrophobic surfaces made of low surface energy (e.g. fluorinated) materials may have water contact angles as high as ~120°. Some materials with highly rough surfaces
Type 90 75 mm field gun and Battle of Okinawa, often deployed together with armored units. The Type 90 continued to be used as field artillery until the surrender of Japan. The Type 90 formed the basis for the Type 3 75 mm tank gun used in the Type 3 Ho-Ni III Gun tank and Type 3 Chi-Nu medium tank. Type 90 75 mm field gun The was a field gun used by the Imperial Japanese Army during the Second Sino-Japanese War, Soviet-Japanese Border Wars and World War II. The Type 90 designation was given to this gun as it was accepted in the year 2590