Abstract: A pneumatic tire includes a tread portion provided with a land portion with a plurality of lateral grooves extending across the land portion. Each lateral groove includes a main portion with a width equal to or more than 2.0 mm and a sipe portion extending radially inwardly from a bottom of the main portion. The main portion includes a first wall located on a first side in a circumferential direction and a second wall located on a second side in the circumferential direction. The sipe portion includes a first sipe wall located on the first side and a second sipe wall located on the second side. The lateral grooves include a first lateral groove having the first wall being continuous to the first sipe wall smoothly and a second lateral groove having the second wall being continuous to the second sipe wall smoothly.

Abstract: A pneumatic tire comprises a tread portion provided with a center main groove on the tire equator and a shoulder main groove on each side of the center main groove. The center main groove and the shoulder main groove extend zigzag and continuously in the tire circumferential direction so that a crown land portion defined between the center main groove and the shoulder main groove has an axial width alternately increasing and decreasing along the tire circumferential direction. The crown land portion is provided with a shallow crown circumferential groove extending zigzag and continuously in the tire circumferential direction, and crown sipes extending from the center main groove to the shoulder main groove across the shallow crown circumferential groove. Zigzag apexes of the shallow crown circumferential groove are respectively positioned between the crown sipes.

Abstract: A pneumatic tire includes a tread portion provided with at least one zigzag main groove extending continuously in a circumferential direction of the tire with a plurality of zigzag corners. The main groove includes a groove bottom and a pair of groove edges. The groove bottom extends in a zigzag manner in the circumferential direction of the tire with a first amplitude. The groove bottom has a width varying periodically so that a maximum width portion and a minimum width portion appear in turn at the zigzag corners. Each of the groove edges extends in a zigzag manner in the circumferential direction of the tire with a second amplitude, wherein the first amplitude is greater than the second amplitude.

Abstract: A heavy duty tire has a carcass extending from a tread portion to a bead core in a bead portion through a sidewall portion, and a belt layer disposed on the outside of the carcass in the tire radial direction and on the inside of the tread portion. In a state in which a distance between a pair of bead heels is kept at 110% of a wheel rim width of a standard wheel rim and no inner pressure is applied, the contour shape of the tread portion is formed by a 1st circular arc having a center on the tire equatorial plane, and a pair of 2nd circular arcs, disposed on both outsides of the 1st circular arc in the tire axial direction. The radius of the 2nd circular arc is more than the radius R1 of the 1st circular arc. One 2nd circular arc has the center on the other 2nd circular arc side of the tire equator in the tire axial direction, and the other 2nd circular arc has the center on the one 2nd circular arc side of the tire equator in the tire axial direction.

Abstract: Provided are an optical transmission structure having a high degree of flexibility in the design of an optical waveguide and a method for manufacturing the optical transmission structure, and also an optical transmission module. An optical transmission structure includes a main substrate (30), a cladding member (40), and core members (50). The main substrate (30) has a through hole (30a) penetrating therethrough in a thickness direction thereof. The cladding member (40) is disposed inside the through hole (30a) and has a plurality of optical waveguide holes (40a) penetrating therethrough in a thickness direction thereof. The core members (50) are disposed inside the plurality of optical waveguide holes (40a), respectively, and have a refractive index larger than the cladding member (40).

Abstract: A heavy duty tire includes a tread portion provided with a pair of circumferential main grooves including at least one zigzag groove, lateral grooves extending between the main grooves to form center blocks therebetween, and lug grooves. Each lug groove includes an axially inner portion connecting to the zigzag groove while curving toward a first circumferential direction of the tire. The lug groove has a first groove edge disposed on a side of the first circumferential direction and a second groove edge facing against the first groove edge. The first groove edge is connected to an axially outer groove edge of the zigzag groove. The second groove edge is connected to an axially inner groove edge of the zigzag groove. The lug groove includes a constant groove width, and a groove-bottom width smoothly decreasing axially inward from the tread edge.

Abstract: A heavy duty pneumatic tire includes a tread portion provided with at least one circumferentially extending main groove, at least one circumferentially extending sub groove, and a plurality of lateral grooves to form repeated pitch elements each of which consists of one lateral groove and a block element. The sub groove includes a shallow bottom part with a depth smaller than that of the main groove. The shallow bottom part of the sub groove is provided with a groove bottom sipe. The lateral grooves include a shallow bottom part with a depth smaller than that of the main groove. The shallow bottom part of the lateral groove is provided with a groove bottom sipe. The lateral grooves have groove widths W2 in a range of from 5% to 15% in relation to a circumferential length L1 of the pitch element.

Abstract: Provided are an optical transmission structure having a high degree of flexibility in the design of an optical waveguide and a method for manufacturing the optical transmission structure, and also an optical transmission module. An optical transmission structure includes a main substrate (30), a cladding member (40), and core members (50). The main substrate (30) has a through hole (30a) penetrating therethrough in a thickness direction thereof. The cladding member (40) is disposed inside the through hole (30a) and has a plurality of optical waveguide holes (40a) penetrating therethrough in a thickness direction thereof. The core members (50) are disposed inside the plurality of optical waveguide holes (40a), respectively, and have a refractive index larger than the cladding member (40).