Abstract: A hollow golf club head made of metal has a face portion made of a titanium alloy, a crown portion, a sole portion, a toe-side side portion, a back-side side portion, a heel-side side portion, and a hosel portion. Grooves are provided in the crown portion so as to extend in the direction connecting the heel side and the toe side. Ribs are provided in the sole portion so as to extend in the direction connecting the face portion and the back-side side portion.

Abstract: This golf club head is constituted by a front part 1 including a face portion 2 and a crown main portion 3, and a back part 10 forming the remaining portion of the golf club head. A metal material forming the front part 1 has lower Young's modulus than that of a metal material forming the back part 10. The front part 1 and the back part 10 are welded. The thickness of the center of the face portion 2 is larger than the thickness of the periphery thereof. The thickness of the vicinity of a highest point 3A of the crown is small.

Abstract: A golf club head has a face portion, a crown portion, a sole portion, a side portion and a hosel portion. Each portion is made of titanium or a titanium alloy. The side portion is formed integrally entirely from its toe side to its back side and its heel side. The side portion and the hosel portion are cast integrally. The face portion, the crown portion and the sole portion are molded separately from one another. The face portion, the crown portion, the sole portion and the side portion are welded integrally so as to form a golf club head. The Young's modulus of the crown portion is lower than any Young's modulus of the face portion, the sole portion, the side portion and the hosel portion.

Abstract: A hollow golf club head made of metal has a face portion made of a titanium alloy, a crown portion, a sole portion, a toe-side side portion, a back-side side portion, a heel-side side portion, and a hosel portion. Grooves are provided in the crown portion so as to extend in the direction connecting the heel side and the toe side. Ribs are provided in the sole portion so as to extend in the direction connecting the face portion and the back-side side portion.

Abstract: A golf club head has a face portion, a crown portion, a sole portion, a side portion and a hosel portion. Each portion is made of titanium or a titanium alloy. The side portion is formed integrally entirely from its toe side to its back side and its heel side. The side portion and the hosel portion are cast integrally. The face portion, the crown portion and the sole portion are molded separately from one another. The face portion, the crown portion, the sole portion and the side portion are welded integrally so as to form a golf club head. The Young's modulus of the crown portion is lower than any Young's modulus of the face portion, the sole portion, the side portion and the hosel portion.

Abstract: In a golf club head with a loft angle in a range of from 5 to 30 degrees, the golf club head comprises a metal body having a hollow portion and having a face portion, a thick portion is formed on the back surface of the face portion, when counted from behind the face portion to the face portion side, the thick portion has N steps (N≧2) so that a centroid of a cut surface of the first step is distanced by 1 mm or more from a centroid of the face surface, and a centroid of a cut surface of the Nth step is distanced by 1 mm or more from a centroid of a cut surface of the N-1th step.

Abstract: This golf club head is constituted by a front part 1 including a face portion 2 and a crown main portion 3, and a back part 10 forming the remaining portion of the golf club head. A metal material forming the front part 1 has lower Young's modulus than that of a metal material forming the back part 10. The front part 1 and the back part 10 are welded. The thickness of the center of the face portion 2 is larger than the thickness of the periphery thereof. The thickness of the vicinity of a highest point 3A of the crown is small.

Abstract: A wood club head provided with a metal shell and having a head volume of 200 cc or more, wherein the ratio (H/W) of a maximum height (H) of a face (2) acting as a hitting surface to a maximum width (W) of the face is set to be in a range of 0.65≦(H/W)≦1.0, and the area of the face is set to be not smaller than 20 cm2.

Abstract: In a golf club head with a loft angle in a range of from 5 to 30 degrees, the golf club head comprises a metal body having a hollow portion and having a face portion, a thick portion is formed on the back surface of the face portion, when counted from behind the face portion to the face portion side, the thick portion has N steps (N≧2) so that a centroid of a cut surface of the first step is distanced by 1 mm or more from a centroid of the face surface, and a centroid of a cut surface of the Nth step is distanced by 1 mm or more from a centroid of a cut surface of the N-1th step.

Abstract: An element for electrophoresis suitably employable for analysis of biopolymers such as proteins, as well as for determination of base sequence of DNA, RNA, their fragments, and their derivatives, which comprises a plastic material support, an adhesive layer containing an inorganic oxide and a binder, a medium layer for electrophoresis comprising an aqueous polyacrylamide gel formed by crosslinking polymerization of an acrylamide compound and a crosslinking agent in the presence of water, and a plastic material covering film. The electrophoresis medium layer may contain a water-soluble polymer and agarose. The medium layer may contain a modifier such as an anionic surfactant, formamide or urea.