摘要:
There is described an electrorheological fluid comprising particles of a composite material suspended in an electrically insulating hydrophobic liquid. The composite particles are metal salts of the form M1xM22-2xTiO(C2O4)2 where M1 is selected from the group consisting of Ba, Sr and Ca and wherein M2 is selected from the group consisting of Rb, Li, Na and K, and the composite particles further include a promoter selected from the group consisting of urea, butyramide and acetamide.
摘要:
A waveguide structure is described wherein microwaves or radio-frequency waves can be guided in their propagation through channels whose cross-sections contain fractal patterns, with relevant dimensions much smaller than the wavelengths of the guided waves. A finite section of such waveguide can be used as an efficient delay line.
摘要:
A “paper look-alike” display comprises pixels formed of dielectric particles suspended in a non-conducting liquid. By applying a voltage to electrodes the particles may be switched between positions in which they are stored in vertical columns normal to the surface of the pixel and have no effect on the color of the pixel, and a position in which they occupy a major part of the surface area of the pixel and influence the color of the pixel accordingly.
摘要:
A lithium ion battery is disclosed in which the negative electrode material comprises carbon nanostructures having no dimension greater than 2 μm. The battery has a high reversible capacity of the order of 400 mAh/g to 500 mAh/g which can be maintained over a long cycle-life (at least 30 cycles). The carbon nanostructures may be mixed with graphite to improve conductivity. The carbon nanostructues may be synthesized using an AFI template material followed by calcination.
摘要:
A waveguide structure is described wherein microwaves or radio-frequency waves can be guided in their propagation through channels whose cross-sections contain fractal patterns, with relevant dimensions much smaller than the wavelengths of the guided waves. A finite section of such waveguide can be used as an efficient delay line.
摘要:
Acoustic attenuation materials are described that comprise outer layers of a stiff material sandwiching a relatively soft elastic material therebetween, with means such as spheres, discs or wire mesh being provided within the elastic material for generating local mechanical resonances that function to absorb sound energy at tunable wavelengths.
摘要:
A method for fabricating a periodic dielectric structure which exhibits a photonic band gap. Alignment holes are formed in a wafer of dielectric material having a given crystal orientation. A planar layer of elongate rods is then formed in a section of the wafer. The formation of the rods includes the step of selectively removing the dielectric material of the wafer between the rods. The formation of alignment holes and layers of elongate rods and wafers is then repeated to form a plurality of patterned wafers. A stack of patterned wafers is then formed by rotating each successive wafer with respect to the next-previous wafer, and then placing the successive wafer on the stack. This stacking results in a stack of patterned wafers having a four-layer periodicity exhibiting a photonic band gap.
摘要:
A periodic dielectric structure which is capable of producing a photonic band gap and which is capable of practical construction. The periodic structure is formed of a plurality of layers, each layer being formed of a plurality of rods separated by a given spacing. The material of the rods contrasts with the material between the rods to have a refractive index contrast of at least two. The rods in each layer are arranged with their axes parallel and at a given spacing. Adjacent layers are rotated by 90.degree., such that the axes of the rods in any given layer are perpendicular to the axes in its neighbor. Alternating layers (that is, successive layers of rods having their axes parallel such as the first and third layers) are offset such that the rods of one are about at the midpoint between the rods of the other. A four-layer periocity is thus produced, and successive layers are stacked to form a three-dimensional structure which exhibits a photonic band gap. By virtue of forming the device in layers of elongate members, it is found that the device is susceptible of practical construction.
摘要:
The present invention relates to planar materials having bandgap properties. The materials are formed by depositing conductive fractal patterns on a non-conducting substrate. The bandgap location(s) are defined by parameters including the number of fractal levels, and the dimension of the fractal mother element. The bandgaps can also be actively controlled by injecting current into the conducting pattern.