64results about How to "Reduce cross sensitivity" patented technology

Nanostructure sensing devices for detecting an analyte are described. The devices include nanostructures connected to conductive elements, all on a substrate. Contact regions adjacent to points of contact between the nanostructures and the conductive elements are given special treatment. The proportion of nanostructure surface area within contact regions can be maximized to effect sensing at very low analyte concentrations. The contact regions can be passivated in an effort to prevent interaction between the environment and the contact regions for sensing at higher analyte concentrations and for reducing cross-sensing. Both contact regions and at least some portion of the nanostructures can be covered with a material that is at least partially permeable to the analyte of interest and impermeable to some other species to tune selectivity and sensitivity of the nanostructure sensing device.

The invention relates to a capacitive micro-acceleration sensor with a symmetrically combined elastic beam structure and a production method thereof. The acceleration sensor comprises a symmetric center mass block, an external support frame, eight symmetric straight beams, two symmetric frame beams, a combined elastic beam structure, an upper cover plate and a lower cover plate, wherein the eight symmetric straight beams are used for connecting the center mass block with the external support frame, and the combined elastic beam structure is formed by connecting eight symmetric L-shaped beams together; and the other end of each straight elastic beam connected with the frame beams is connected to the middle or a vertex angle at the top end and the bottom end of the lateral face of the center mass block, and the other end of each L-shaped beam connected with the frame beams is connected to the inner side face of the external support frame. The acceleration sensor adopts the combined elastic beam structure which is formed by connecting the symmetric straight beams, the frame beams and the L-shaped beams together, has high symmetry and can remarkably reduce the cross-sensitivity of the sensor; and the sensor is produced by adopting a microelectronic mechanical system technology and is the capacitive micro-acceleration sensor with high sensitivity.

Relevant fuel-gas properties (X_G) are measured on an ongoing basis while a gas turbine group is operating. The C₂₊alkane content of the fuel gas is of particular interest in this context, since it has a significant influence on the ignitability of the fuel gas in the combustion chamber. The operating parameters of the gas turbine group are acted on directly as a function of the measured fuel-gas properties. In particular, in the case of the example of a gas turbine group with sequential combustion, the distribution of the fuel mass flows ({dot over (m)}_EV, {dot over (m)}_SEV) between the combustion chambers (4, 8) of the gas turbine group is varied. Furthermore, if there is provision for inert media, such as water or steam, to be introduced, it is possible for the mass flow of inert media ({dot over (m)}_ST) to be controlled as a function of the measured fuel properties.

A micromechanical capacitive acceleration sensor having at least one seismic mass that is connected to a substrate so as to be capable of deflection, at least one electrode connected fixedly to the substrate, and at least one electrode connected to the seismic mass, the at least one electrode connected fixedly to the substrate and the at least one electrode connected to the seismic mass being realized as comb-shaped electrodes having lamellae that run parallel to the direction of deflection of the seismic mass, the lamellae of the two comb-shaped electrodes overlapping partially in the resting state.

A sensor for detecting particles in a gas flow, in particular soot particles in an exhaust gas flow, includes at least two measuring electrodes, which are positioned on a substrate made of an insulating material. To protect the measuring electrodes, they are covered by a protective layer.

The invention discloses an MEMS piezoresistance type two-axis acceleration sensor chip and a preparing method thereof. The MEMS piezoresistance type two-axis acceleration sensor chip comprises four sets of same sub-structures. The four sub-structures are uniformly distributed at the periphery of a fixed island. The fixed island is connected with a mass block through an inner supporting beam. The mass block is connected with an outer frame through an outer supporting beam. Sensitive beams are symmetrically distributed at two sides of the outer supporting beam. One end of the sensitive beam is connected with one end of the mass block, and the other end of the sensitive beam is connected with the outer frame. The two sub-structures which face each other relative to the fixed island form a set, thereby forming a whole working structure for measuring one acceleration direction, thereby respectively measuring the accelerations in an X-axis and a Y-axis. The two sensitive beams of each sub-structure are respectively provided with a pressure-sensitive resistor and are connected with a pad through metal leads, thereby forming a semi-open-ring Wheatstone full-bridge circuit. The sensor chipcan realize separated measurement of the accelerations below 200g in two axes. The natural frequency of the MEMS piezoresistance type two-axis acceleration sensor reaches above 20kHz, and the sensitivity is higher than 0.5mB/g/3V. Furthermore the MEMS piezoresistance type two-axis acceleration sensor chip has relatively high resonant frequency and high sensitivity.

An electrochemical gas sensor (9) has improved electrochemical measurement properties and housing tightness for an electrolyte at the sites at which the connection lines (11, 21, 31) pass through. The sensor (9) includes a housing (4), containing at least one measuring electrode (1) and a counterelectrode (2) and with electric connection lines (11, 21, 31) from the electrodes (1, 2, 3) to a measuring unit (8) arranged outside the housing (4). The electric connection lines (11, 21, 31) include carbon nanotubes (CNT, Carbon Nanotubes) at least in some sections in the housing (4) in the area of the electrolyte wetting.

The invention provides a full single-mode fiber F-P sensor and a manufacturing method thereof. The full single-mode fiber F-P sensor is made of full single-mode fibers, multiple times of cutting are not needed, the fibers are welded for multiple times, the operation is simple, and the cost is low, and meanwhile, the cross sensitivity problem between the single-mode fibers and the multi-mode fiberscan be reduced; the number of welding times is small, and the problem that the mechanical strength of the sensor is reduced due to the fact that the loss is increased by welding the fibers for many times is effectively solved. The full single-mode fiber F-P strain sensor is obtained by adopting a chemical corrosion method, and is small in structure and less in temperature influence, can measure the pressure and strain, and the problem of cross sensitivity is reduced.

A capacitive acceleration sensor with an “H”-shaped beam and a preparation method. The sensor at least includes: a first electrode structural layer, a middle structural layer and a second electrode structural layer; the first electrode structural layer and the second electrode structural layer are provided with electrode lead via holes, respectively; the middle structural layer includes: a frame formed at SOI silicon substrate having a double device layer, a seismic mass whose double sides are symmetrical, and an “H”-shaped elastic beam whose double sides are symmetrical, with one end connected to the frame and the other end connected to the seismic mass, there are anti-overloading bumps and damping grooves symmetrically provided on the two sides of the seismic mass, and the “H”-shaped elastic beam and a bulk silicon layer of the oxygen containing silicon substrate satisfy the requirements therebetween:

√{square root over (2)}(a+b+c)<h,

√{square root over (2)}d<h.

The invention discloses a gas detection system based on an MEMS gas sensor array. The gas detection system comprises the MEMS gas sensor array, a time division multiplexing multi-channel resistance frequency conversion circuit, a programmable heater circuit, an EEPROM, a trimmable on-chip oscillator, a power-on self-reset circuit and a digital control circuit. The MEMS gas sensor array comprises a plurality of gas sensors; the gas sensor comprises a heater resistor and a gas sensitive material resistor; the MEMS gas sensor array is used for converting gas information in the environment into resistance change of the gas sensitive material; the multi-channel resistance frequency conversion circuit is used for converting the resistance value of the gas sensitive material of the selected channel into a square wave signal with a corresponding frequency; and the on-chip oscillator is used for generating a stable clock signal required by the system. By applying the technical scheme provided by the invention, the working voltage and the circuit power consumption can be reduced, and the detection range and the detection precision of the gas sensitive material resistor in the gas sensor are improved.

The invention discloses an in-plane biaxial piezoresistive acceleration sensor chip and a preparation method thereof. A chip is made of an SOI silicon wafer, and comprises a chip outer frame. A fixingisland is arranged in the middle of each side of the chip outer frame, a supporting beam is of an L-shaped structure, one end of a long section of the supporting beam is fixed to the chip outer framethrough the fixing islands, the other short section of the supporting beam is sequentially connected with an extending beam and a mass block, and a sensitive piezoresistive micro beam is arranged ina gap between the tail end of the extending beam and the fixing islands. All the eight mass blocks are connected through hinge beams to be square. A piezoresistor on the sensitive piezoresistive microbeam is connected with a bonding pad through a metal lead to form a Wheatstone full-bridge circuit. The extension beam is used as an intermediate structure for connecting the sensitive piezoresistivemicro-beam, the support beam and the mass blocks, and transmits the change of the motion state of the mass blocks to the sensitive piezoresistive micro-beam. According to the piezoresistive acceleration sensor chip, the supporting element and the sensitive element are separated, the dynamic performance and the application range of the piezoresistive acceleration sensor are improved, the preparation method is simple, and the reliability is high.

A particle sensor including a diaphragm, a diaphragm heater, and at least two measuring electrodes situated on the diaphragm, for electrical conductivity measurement, the diaphragm having a thickness of less than or equal to 50 μm, in order to allow a calorimetric particle quantity determination.

A method for measuring the concentration of a gas component in a measuring gas, wherein a semiconductor laser is periodically actuated by a current ramp to scan a selected absorption line in a wavelength-dependent manner and to determine the concentration of the gas component based on the reduction in the light intensity as a result of the absorption of the light at the location of the absorption line.

The invention discloses a control system for self-adaptive correction of urea injection on the basis of a NOx sensor. The control system comprises an input signal module, the input signal module is connected with a NOx/NH3 rationality verification and calculation module, a correction coefficient adjustment module and a urea injection amount calculation module separately, the NOx/NH3 rationality verification and calculation module is connected with the correction coefficient adjustment module, the urea injection amount calculation module and an output signal module separately, the correction coefficient adjustment module is connected with the urea injection amount calculation module and the output signal module separately, and the urea injection amount calculation module is connected with the output signal module. Therefore, the urea injection amount can be precisely controlled according to the flow of NOx in a catalyst, and the robustness of an SCR closed-loop system can be enhanced.