摘要:
Disclosed is an .alpha.-methylcinnamic acid ester derivative represented by the formula: ##STR1## wherein n is an integer of from 5 to 18, R.sub.1 represents an optically active group of the formula ##STR2## in which m is an integer of from 1 to 5 and *C represents an asymmetric carbon atom, and R.sub.2 represents ##STR3##The .alpha.-methylcinnamic acid ester derivative is valuable as a ferroelectric liquid crystal or an additive to a ferroelectric liquid crystal.
摘要:
Disclosed is an optically active substance represented by the formula: ##STR1## wherein m is an integer of 1 to 14, Y is ##STR2## R is --C.sub.n H.sub.2n+1, --OC.sub.n H.sub.2n+1, --OCOC.sub.n H.sub.2n+1 or --COOC.sub.n H.sub.2n+1 (in which n is an integer of 1 to 18), each of the asterisked carbon atoms is an asymmetric carbon atom, X a single bond, --CO.sub.2 --, or --OCO--, and A.sub.1 and A.sub.2 is hydrogen, fluorine, chlorine, bromine, cyano or methoxy.
摘要:
An antenna coil includes a wound body including a magnetic core, a bobbin surrounding the magnetic core, and a coil wound around the bobbin, a case in which the wound body is placed, and a foam disposed in a gap between the wound body and the case. The foam is compressed at a rate of about 45% to about 65% on the basis of a thickness of the foam in a non-load state. The antenna coil prevents breakage of the magnetic core and is suitable for use in a short-distance communication system in an LF-band.
摘要:
Provided is a porous electrode substrate having excellent thickness precision, gas permeability and conductivity, handling efficiency, low production costs and a high carbonization rate during carbonization. Also provided are a method for manufacturing such a substrate, a precursor sheet and fibrillar fiber used for forming such a substrate, along with a membrane electrode assembly and a polymer electrolyte fuel cell that contain such a substrate. The method for manufacturing a porous electrode substrate includes step (1) for manufacturing a precursor sheet in which short carbon fibers (A) and carbon fiber precursor (b) are dispersed, and step (2) for carbonizing the precursor sheet, and the volume contraction rate of carbon fiber precursor (b) in step (2) is 83% or lower. The present invention also relates to a porous electrode substrate obtained by such a manufacturing method, a precursor sheet and fibrillar fiber used for forming the substrate, along with a membrane electrode assembly and a polymer electrolyte fuel cell containing the substrate.
摘要:
Provided are: a porous electrode substrate which has excellent handling properties and surface smoothness and satisfactory gas permeability and electrical conductivity, and enables the reduction of damage to a polymer electrolyte membrane when integrated into a fuel cell; and a process for producing the porous electrode substrate. Specifically provided are: a porous electrode substrate comprising a three-dimensional structure (Y-1) produced by bonding short carbon fibers through carbon and a three-dimensional structure (Y-2) produced by bonding short carbon fibers through carbon, wherein the three-dimensional structures (Y-1) and (Y-2) are layer stacked on and integrated with each other, the short carbon fibers form a three-dimensional entangled structure in the structure (Y-1), and the short carbon fibers do not form a three-dimensional entangled structure in the structure (Y-2); a process for producing the electrode base material; a precursor sheet for producing the electrode base material; a membrane-electrode assembly which involves the electrode base material; and a polymer electrolyte fuel cell.
摘要:
The present invention provides a porous electrode substrate that has low production cost, high mechanical strength, thickness precision, and surface smoothness, and sufficient gas permeability and electrical conductivity, and a method for producing the same. In the present invention, for example, a porous electrode substrate that includes short carbon fibers (A) joined together via three-dimensional mesh-like carbon fibers (B) is produced by a method including a step (1) of dispersing short carbon fibers (A), and short carbon fiber precursors (b) to be fibrillated by beating, to produce a precursor sheet; and a step (2) of subjecting the precursor sheet to carbonization treatment at a temperature of 1000° C. or higher.
摘要:
Provided are: a porous electrode substrate which has excellent handling properties and surface smoothness and satisfactory gas permeability and electrical conductivity, and enables the reduction of damage to a polymer electrolyte membrane when integrated into a fuel cell; and a process for producing the porous electrode substrate. Specifically provided are: a porous electrode substrate comprising a three-dimensional structure (Y-1) produced by bonding short carbon fibers through carbon and a three-dimensional structure (Y-2) produced by bonding short carbon fibers through carbon, wherein the three-dimensional structures (Y-1) and (Y-2) are layer stacked on and integrated with each other, the short carbon fibers form a three-dimensional entangled structure in the structure (Y-1), and the short carbon fibers do not form a three-dimensional entangled structure in the structure (Y-2); a process for producing the electrode base material; a precursor sheet for producing the electrode base material; a membrane-electrode assembly which involves the electrode base material; and a polymer electrolyte fuel cell.
摘要:
Provided is a porous electrode substrate having high mechanical strength, good handling properties, high thickness precision, little undulation, and adequate gas permeability and conductivity. Also provided is a method for producing a porous electrode substrate at low costs. A porous electrode substrate is produced by joining short carbon fibers (A) via mesh-like of carbon fibers (B) having an average diameter of 4 μm or smaller. Further provided are a membrane-electrode assembly and a polymer electrolyte fuel cell that use this porous electrode membrane. A porous electrode substrate is obtained by subjecting a precursor sheet, in which short carbon fibers (A) and short carbon fiber precursors (b) having an average diameter of 5 μm or smaller have been dispersed, to carbonization treatment after optional hot press forming and optional oxidization treatment.
摘要:
Provided is a porous electrode substrate having excellent thickness precision, gas permeability and conductivity, handling efficiency, low production costs and a high carbonization rate during carbonization. Also provided are a method for manufacturing such a substrate, a precursor sheet and fibrillar fiber used for forming such a substrate, along with a membrane electrode assembly and a polymer electrolyte fuel cell that contain such a substrate. The method for manufacturing a porous electrode substrate includes step (1) for manufacturing a precursor sheet in which short carbon fibers (A) and carbon fiber precursor (b) are dispersed, and step (2) for carbonizing the precursor sheet, and the volume contraction rate of carbon fiber precursor (b) in step (2) is 83% or lower. The present invention also relates to a porous electrode substrate obtained by such a manufacturing method, a precursor sheet and fibrillar fiber used for forming the substrate, along with a membrane electrode assembly and a polymer electrolyte fuel cell containing the substrate.