摘要:
Electrical contact surfaces of a bipolar plate for a fuel cell assembly are formed of metals or metal alloys which when oxidized form highly conductive oxide passivation layers, thus maintaining high electrical conductivity and continuity through the fuel cell and forestalling corrosion failure of a cell assembly. Alloy composition systems such as, but not limited to, Ti—Nb, Ti—Ta, La—Sr—Cr, and La—Sr—Co are known to form oxide passivation layers which are highly conductive. The passivation layers may be formed in situ after assembly of a fuel cell or may be provided in an oxidative step during manufacture. The bipolar plate may be formed entirely of one or more of such alloys or may be formed of an inexpensive substrate metal having the alloy layers coated thereupon.
摘要:
A metal alloy which when oxidized forms a highly conductive surface oxide layer. Alloy compositions such as, but not limited to, Ti—Nb, Ti—Ta, La—Sr—Cr, and La—Sr—Co are known to form oxide passivation layers which are highly conductive. Such alloys are useful in electrical contact apparatus. An electrical contact element formed of the alloy has a contact surface which when oxidized forms a highly conductive surface layer, thus maintaining electrical conductivity and continuity through the element. The oxide layer may be formed in situ after assembly of the electrical contact or may be provided in an oxidative step during manufacture. The electrical contact may be formed entirely of one or more of such alloys; or may be formed of an inexpensive substrate base metal, such as steel, having one or more of the alloys coated thereupon; or may be formed of a mixture of the base metal and the alloy.
摘要:
Barium-strontium titanate ferroelectric materials and AFe.sub.2 O.sub.4 -type ferrite ferromagnetic materials may be consolidated into a ferroelectric-ferromagnetic composite having useful electromagnetic interference attenuation properties over a wide range of electromagnetic frequencies by fluxing the barium-strontium titanate with a combination of (1) a lithium compound and barium oxide or (2) copper oxide and barium oxide and thereafter mixing the fluxed ferroelectric with the ferromagnetic and sintering the combination at reduced temperature in the range of 1060.degree. C. to 1150.degree. C.
摘要翻译:钡钛酸锶铁电材料和AFe 2 O 4型铁氧体铁磁材料可以通过以下方式组合使用钛酸锶钛酸锶而将其固化成铁电铁磁性复合材料,该复合材料在广泛的电磁频率范围内具有有用的电磁干扰衰减特性:(1) 锂化合物和氧化钡或(2)氧化铜和氧化钡,然后将熔融的铁电体与铁磁体混合,并在1060℃至1150℃的温度范围内烧结组合。
摘要:
A film having a unique asymmetrical hysteresis, a method of making, and a method of using such a film in and/or as a device. An example describes a distinctive ferroelectric device as an infrared detector that operates at generally ambient conditions.
摘要:
A film having a unique asymmetrical hysteresis, a method of making, and a method of using such a film in and/or as a device. An example describes a distinctive ferroelectric device as an infrared detector that operates at generally ambient conditions.
摘要:
A composite structure with tailored anisotropic energy flow is described. The structure consists of an array of two-dimensional electrodes with anisotropic geometrical shapes on a semiconductor or semimetal layer that in turn is on a metal baselayer. An applied voltage between the two-dimensional electrode array and the baselayer renders the regions under the electrodes insulating such that the anisotropic regions interact with energy flow in the semiconductor or semimetal layer. Depending on the orientation of the anisotropic insulating regions with respect to the principal direction of energy flow, the energy flow in the semiconductor or semimetal layer is greater in a principal direction and is lower in an opposite direction.
摘要:
The invention is a bulk-processed thermoelectric material and a method for fabrication. The material measures at least 30 microns in each dimension and has a figure of merit (ZT) greater than 1.0 at any temperature less than 200° C. The material comprises at least two constituents; a host phase and a dispersed second phase. The host phase is a semiconductor or semimetal and the dispersed phase of the bulk-processed material is comprised of a plurality of inclusions. The material has a substantially coherent interface between the host phase and the dispersed phase in at least one crystallographic direction.
摘要:
An example method of detecting components of a gas includes detecting substantially all components of a gas using distinct infrared wavelengths within a portion of the infrared spectrum, the portion being less than the entire infrared spectrum.
摘要:
An exemplary detector includes a source of radiation. A detection chamber is configured to at least temporarily contain a fluid. At least some of the radiation ionizes at least some of the fluid. At least some of the radiation produces light in the detection chamber. An ionization sensor provides an output corresponding to an amount of fluid ionization in the detection chamber. A light sensor provides an output corresponding to an amount of the light detected by the light sensor.
摘要:
Systems and methods for determining a temperature of a ferroelectric sensor are provided. The ferroelectric sensor has operational characteristics defined by a polarization versus voltage hysteresis loop. In one exemplary embodiment, the method includes applying a symmetrical periodic voltage waveform to the ferroelectric sensor so as to induce the ferroelectric sensor to traverse the polarization versus voltage hysteresis loop. The method further includes monitoring voltages across the ferroelectric sensor and polarization states of the ferroelectric sensor over a first time interval to determine a first zero field polarization state and a first coercive field voltage. The method further includes determining a first temperature value indicative of the temperature of the ferroelectric sensor based on the first coercive field voltage.