194 resultados para patent(s)
Resumo:
A sensor for chemical species or biological species or radiation presenting to test fluid a polymer composition comprises polymer and conductive filler metal, alloy or reduced metal oxide and having a first level of electrical conductance when quiescent and being convertible to a second level of conductance by change of stress applied by stretching or compression or electric field, in which the polymer composition is characterised by at least one of the features in the form of particles at least 90% w/w held on a 100 mesh sieve; and/or comprising a permeable body extending across a channel of fluid flow; and/or affording in-and-out diffusion of test fluid and/or mechanically coupled to a workpiece of polymer swellable by a constituent of test fluid.
Resumo:
A measurement system for magnetic fields or electric currents uses a single-core fluxgate, magneto-inductive or magneto-impedance device driven from a radio frequency excitation source. Flux nulling feedback circuitry is provided to maintain the core of the sensor at substantially zero net flux and improve the linearity and dynamic response of the sensor system. A high pass filter is provided for reducing the dc effects of the ohmic resistance of the coil and lead wires on the effectiveness of the flux nulling feedback.
Resumo:
A measurement system for magnetic fields and electric currents uses a single-core fluxgate device driven with a radio frequency excitation source and is provided with a means to indicate saturation of the core of the sensor. A means is provided for detecting overload of the sensor as the core approaches continuous saturation using a pair of demodulators and a comparator.
Resumo:
A blade (2) for a compressor comprising a pressure surface (6) and a suction surface (4), wherein the suction surface (4) comprises: a discontinuity in the chord-wise curvature of an intermediate portion of the suction surface between the blade leading edge and blade trailing edge; and a slot (20) arranged along at least a portion of the blade (2) in a substantially span-wise direction, the slot (2) being disposed at or near the said change in curvature, such that when in use lower momentum fluid near the suction surface (4) is aspirated into the slot (20).
Resumo:
A method and device for periodically perturbing the flow field within a microfluidic device to provide regular droplet formation at high speed.
Resumo:
A radiation concentrator device 21 for improved efficiency in solar systems by limiting reflected light, comprising a radiation concentrator element 27 comprising a radiation transmissive surface 29, a radiation receiving device and disposed on the incident radiation side of the concentrator element 27 is a recapture element 23 for recapturing at least a portion of radiation lost from the concentrator element 27, where the recapturing element allows transmission of incident light into the concentrator element 27, recaptures escaping radiation from the concentrator element and reflecting the radiation back into the concentrator element. Also disclosed are radiation concentrator device 21 where the recapture element 23 comprises ridged or grooved structures to increase the internal reflection of the radiation. The concentrator element 27 may also be provided with luminescent materials.
Resumo:
A method of creating micro patterned devices by patterning thin films which are deposited on a substrate. A channel or channels is created on the substrate, the width being of fine enough resolution such that a flowable mask material can be drawn along the channel by capillary forces
Resumo:
A method of creating micro patterned devices by patterning thin films which are deposited on a substrate. A channel or channels is created on the substrate, the width being of fine enough resolution such that a flowable mask material can be drawn along the channel by capillary forces.
Resumo:
A method of patterning a flowable material on a surface, the method comprising providing the surface with at least one channel and at least one through- hole with at least two openings, wherein at least one of the openings is located in the surface adjacent to the at least one channel, such that when flowable material is deposited adjacent to another of the at least two openings, the material is directed into the at least one through-hole by the action of capillary forces and emerges at the opening adjacent to the at least one channel whereupon it is further directed along said channel.
Resumo:
The invention provides a multilayer electronic device having electrodes, formed on a laterally extending first layer, the lateral position of each of at least two adjacent electrodes being defined by a channel in the first layer. Each channel is adjacent a deposition region, the material which forms each electrode substantially covering the deposition region to form a continuous conductive structure.
Resumo:
We describe an RFID tag reading system for reading one or more RFID Tags, the system comprising an RF transmitter and an RF receiver, a plurality of transmit/receive antennas coupled to said RF transmitter and to said RF receiver, to provide spatial transmit/receive signal diversity, and a tag signal decoder coupled to at least said RF receiver, wherein said system is configured to combine received RF signals from said antennas to provide a combined received RF signal, wherein said RF receiver has said combined received RF signal as an input; wherein said antennas are spaced apart from one another sufficiently for one said antenna not to be within the near field of another said antenna, wherein said system is configured to perform a tag inventory cycle comprising a plurality of tag read rounds to read said tags, a said tag read round comprising transmission of one or more RF tag interrogation signals simultaneously from said plurality of antennas and receiving a signal from one or more of said tags, a said tag read round having a set of time slots during which a said tag is able to transmit tag data including a tag ID for reception by said antenna, and wherein said system is configured to perform, during a said tag inventory cycle, one or both of: a change in a frequency of said tag interrogation signals transmitted simultaneously from said plurality of antennas, and a change in a relative phase of a said RF tag interrogation signals transmitted from one of said antennas with respect to another of said antennas.
Resumo:
We describe a methods of locating an RFID tag. One method comprises: transmitting tag location signals from a plurality of different transmit antennas, wherein said antennas are spaced apart by more than a near field limit distance at a frequency of a said signal; receiving a corresponding plurality of receiving return signals from said tag; and processing said tag return signals to determine a range to said tag; wherein said transmitting comprises transmitting at a plurality of different frequencies; wherein said processing comprises determining a phase difference at said plurality of different frequencies to determine said range, and wherein said determining of said phase difference determines a phase difference between either i) two or more of said transmit signals resulting in a maxima in the returned signal RSSI or ii) a first transmit signal and its corresponding return signal; and wherein said determining of said range to said tag uses said return signals weighted responsive to a respective received signal strength of the return signal. Further data which may be used for averaging may be generated by using the above techniques along with changes in the polarisation state of the transmit and receive antennas and/or physical reconfiguration of the antennas (e.g. switch the transmit and receive elements).