91 results about "Negative coefficient" patented technology

A structure of thermal stress compensation at least comprises a substrate, a first film and a second film. The substrate has a first positive coefficient of thermal expansion. The first film having a second positive coefficient of thermal expansion is over the substrate. The second film having a third negative coefficient of thermal expansion is over the substrate.

Disclosed are composites having very low coefficients of thermal expansion and methods of preparing the composites. Also disclosed are composites having negative coefficients of thermal expansion. Applications of the composites to a wide variety of uses, such as electronic and optoelectronic devices are also disclosed.

An abrasive article including a material including an abrasive material and a filler material having an average negative coefficient of thermal expansion (CTE) within a range of temperatures between about 70K to about 1500K.

A CTE modified braze composition that can be utilized to manufacture a strong, gastight joint where at least one of the joining members comprises a ceramic (e.g., a ceramic or a cermet). The braze composition is formulated so as to reduce the thermal stress that results from the mismatch of thermal expansion coefficients between a ceramic joining member and the braze or other joining members. The braze composition comprises a braze alloy in powder, paste or bulk form mixed with one or more particulate or fibrous fillers that exhibit a low (i.e., no more than 6 ppm/K) or negative coefficient of thermal expansion. The braze composition can be used to join members, at least one of which comprises ceramic, and to a composite member produced by joining the two or more members.

The present invention relates to a filler featuring a negative coefficient of thermal expansion and a bi-modal size distribution of filler particles. In an embodiment, the filler has micron and nanometer size filler particles. The present invention also relates to a composite having a polymer and a filler with nanometer size filler particles. Additionally, the present invention discloses a method of forming an electronic package with a composite having a polymer and a filler with nanometer size filler particles.

A method and apparatus for compensating an optical filter is disclosed. The device substantially maintains the selected center wavelength in the optical filter across a range of operating temperatures. In an embodiment of the invention an optical filter is disclosed for filtering a selected channel among a plurality of multiplexed channels of an optical communication. The optical filter includes an optical fiber and an elongate housing. The optical fiber has a first side and a second side and a filter portion intermediate the first side and the second side, and the optical fiber for transmitting the multiplexed optical communication and the filter portion for filtering the selected channel. The elongate housing includes exposed end portions through which the optical fiber extends. The optical fiber is affixed at each exposed end portion. The exposed end portions exhibit between them a negative coefficient of thermal expansion sufficient to generate strains on the filter to substantially stabilize a filtered wavelength to substantially correspond with the selected channel during temperature variations. In an alternate embodiment of the invention the elongate housing is defined about a longitudinal axis and including a first anchor pad and a second anchor pad to which the filter portion is affixed. At least one of the anchor pads is at least initially movable in a plane intersecting the longitudinal axis to vary a strain on the filter portion to tune a center wavelength of the selected channel. In another embodiment of the invention an optical filter for filtering an optical signal is disclosed. In still another embodiment of the invention a method for compensating an optical filter is disclosed.

An edge detection filter comprising an array of filter coefficients having an odd number of rows and columns, a first set of zero coefficients extending along a direction traversing the array through a center position to form a first and second side, a second set of positive coefficients extending away from the direction on the first side, and a third set of negative coefficients extending away from the direction on the second side.

A thermally compensated fiber Bragg grating package is used with a fiber optic sensor. The package includes a Bragg grating mount connected at each end of a sensor mandrel. An optical fiber is wound around the sensor mandrel and a fiber portion having a Bragg grating therein is wound onto the mount. The mount is made of a rigid material having a negative coefficient of thermal expansion to minimize thermally induced spectral shifts. One example of the material includes zirconium tungstate. A coating material can be used to further adhere the optical fiber to the sensor mandrel and/or to the mount. The mount preferably includes a ramped groove to provide for a smooth transition from the sensor mandrel to the mount.

Circuits and methods for providing a temperature insensitive reference current are disclosed. A voltage source is received having a temperature coefficient. A first resistive element having a positive temperature coefficient and a second resistive element having a negative temperature coefficient are series coupled to form a resistor ladder. The reference current is generated by coupling the voltage source across the resistor ladder. The temperature coefficients of the first and second resistive elements are chosen to cancel the temperature coefficient of the voltage source. In another embodiment a temperature compensated voltage source is coupled to a resistor ladder of a first resistive element and a second resistive element, and the first resistive element has a positive temperature coefficient and the second resistive element has a negative coefficient; these cancel to form a temperature insensitive reference current. A method for forming a temperature insensitive reference current from resistive elements is described.

A power storage device includes a fuel cell (33), a battery holder (1) and an end plate (40) for sandwiching and binding the fuel cell, and an interposed member (11) disposed between the end plate (40) and the fuel cell (33). The battery holder (1) and the end plate (40) are made of resin, and have a positive coefficient of thermal expansion at a temperature lower than a predetermined temperature. The interposed member (11) is formed to have a substantially negative coefficient of thermal expansion at a temperature lower than the predetermined temperature.

A slider having a magnetic read/write head and including, a base coat, a reader element having a transducer, a writer element, the writer element including at least one conductive coil, the coil being electrically insulated by a composition which has a negative coefficient of thermal expansion, and an overcoat.

The present invention relates to an electrolyte for producing a novel Fe—Ni alloy having an Ni content in a range of 33 to 42 wt %, specifically a nanocrystalline invar alloy having a grain size of 5 to 15 nm, by electroplating, and preparation conditions thereof. The electrolyte comprises, on the basis of 1 L of water, 32 to 53 g of ferrous sulfate or ferrous chloride, a mixture thereof; 97 g of nickel sulfate, nickel chloride, nickel sulfamate or a mixture thereof; 20 to 30 g of boric acid; 1 to 3 g of sodium saccharin; 0.1 to 0.3 g of sodium lauryl sulfate; and 20 to 40 g of sodium chloride. The Fe—Ni alloy sheet of the present invention exhibits excellent mechanical property compared to the conventional Fe—Ni alloy and a new property, i.e., a negative coefficient of thermal expansion at a given temperature range.

The present invention is to provide a parallel filtering method, which is implemented to an interpolation filter and comprises the steps of separating coefficients of the interpolation filter into two sets comprising the positive and negative coefficients respectively for parallelly filtering a plurality of input data pixels packed into data words inputted to the interpolation filter concurrently to obtain a first result data word, and clipping and shifting the first result data word to obtain a final output data word containing packed half-pel pixels for parallelly and efficiently filtering data stream of video without increasing the complexity, cost, size and power consumption of circuitry of an electronic video apparatus.

A negative coefficient of thermal expansion particle includes a first bilayer having a first bilayer inner layer and a first bilayer outer layer, and a second bilayer having a second bilayer inner layer and a second bilayer outer layer. The first and second bilayers are joined together along perimeters of the first and second bilayer outer layers and first and second bilayer inner layers, respectively. The first bilayer inner layer and the second bilayer inner layer are made of a first material and the first bilayer outer layer and the second bilayer outer layer are made of a second material. The first material has a greater coefficient of thermal expansion than that of the second material.

A structure has an inner, load bearing member and a surrounding, concentric over-wrap. The inner member is composed of a carbon composite and the over-wrap is composed of a non-carbon composite. The inner member has a negative coefficient of thermal expansion and the over-wrap has a positive coefficient of thermal expansion that is an order of magnitude greater than that of the inner member. When subjected to cryogenic temperatures, the over-wrap will shrink and apply a compressive force against the inner member, to resist the creation of microcracks in the inner member.

The invention relates to a microwave photon filter structure which can achieve a negative coefficient and belongs to the field of high-capacity microwave photon communication. The structure consists of a tunable light source (1), a 3db beam splitter (2), a semiconductor amplifier SOA (3), an attenuator or an amplifier (4), a coupler (5), a circulator (6), a Bragg grating (7) and an optoelectronic detector (8). The microwave photon filter structure has the advantages that the characteristic of achieving the negative coefficient of the microwave photon filter is achieved, and finally a light signal passing through a photodiode is converted into a radio frequency signal so that the function of filtering the radio frequency signal in an optical domain is realized directly.

An optical modulator can be provided that includes a substrate; an insulation layer positioned on the substrate; a ribbon layer such that its center portion is spaced apart from the insulation layer; a piezoelectric actuator positioned on either end of the ribbon layer that provides the driving force which moves the center portion of the ribbon layer vertically; and a temperature compensation layer, which is made of a thermally contracting material having a negative coefficient of expansion, and which is formed on at least one position of an upper portion of the piezoelectric actuator, a lower portion of the piezoelectric actuator, and a lower surface of the ribbon layer corresponding to a position of the piezoelectric actuator. In the optical modulator, the problem of thermal deformation due to rises in temperature can be resolved, whereby the accuracy and reliability of operation of the component can be increased.

The superconductive nanocomposite is a composition formed by nanoparticles of a high temperature superconductor blended with a polymer matrix containing natural rubber and polyethylene. The high temperature superconductor is preferably a bismuth-based superconductor (BSCCO) having a particle size of about 21 nm, but may be any other high temperature or Type II ceramic, metal oxide superconductor. The superconductor nanoparticles comprise about 15% of the weight of natural rubber in the composition. The polyethylene is preferably low density polyethylene and may comprise between 0% up to about 40% of the weight of natural rubber in the composition. The nanocomposite may be prepared by blending the components and roll milling the rubber. Depending upon the percentage of polyethylene present in the matrix, the nanocomposite has useful applications as a double thermistor (both positive and negative coefficients of electrical resistivity), for antistatic charge dissipation, and for electromagnetic shielding in the microwave region.

An inorganic filler has a negative coefficient of thermal expansion, and a shell thereon that decreases diffusion of ions contained in the inorganic filler to outside of the shell and organic filler.

A liquid crystal display device (1) according to the invention adds a former image and a latter image which are continuous. When an image corresponding to a received video signal is a still image, an effect of noise reduction is provided by multiplying the former image by a positive coefficient. On the other hand, when an image corresponding to the received video signal is a moving image, a difference between the former image and the latter image is obtained by multiplying the former image by a negative coefficient, thereby providing an effect of overdrive.