110 results about "Ionization current" patented technology

A single dielectric barrier aerodynamic plasma actuator apparatus based on the dielectric barrier discharge phenomenon is disclosed and suggested for application to aerodynamic uses for drag reduction, stall elimination and airfoil efficiency improvement. In the plasma actuator apparatus non-uniform in time and space, partially ionized gasses are generated by one or more electrode pairs each having one electrically encapsulated electrode and one air stream exposed electrode and energization by a high-voltage alternating current waveform. The influence of electrical waveform variation, electrode polarity, electrode size and electrode shape on the achieved plasma are considered along with theoretical verification of achieved results. Light output, generated thrust, ionizing current waveform and magnitude and other variables are considered. Misconceptions prevailing in the present day plasma generation art are addressed and are believed-to-be corrected. The influence of electrostatic shielding effects of the developed plasma on the applied electric field are also considered.

A semiconductor die is described. This semiconductor die includes an electro-static discharge (ESD) device with a metal component coupled to an input-output (I / O) pad, and coupled to a ground voltage via a signal line. Moreover, adjacent edges of the metal component and the I / O pad are separated by a spacing that defines an ESD gap. When a field-emission or ionization current flows across the ESD gap, the metal component provides a discharge path to the ground voltage for transient ESD signals. Furthermore, the ESD gap is at least partially enclosed so that there is gas in the ESD gap.

Methods and apparatus are provided an electrostatic discharge (ESD) protection device having a first terminal and a second terminal. The ESD protection device comprises a vertical transistor having a collector coupled to the first terminal, a base, and an emitter coupled to the second terminal. A zener diode has a first terminal coupled to the first terminal of the ESD protection device and a second terminal coupled to the base of the vertical transistor. Subsurface current paths are provided to redistribute current from a surface of the vertical transistor in an ESD event. The method comprises generating an ionization current when a zener diode breaks down during an ESD event. The ionization current density from a surface zener diode region is reduced. The ionization current enables a transistor to dissipate the ESD event.

Methods and apparatus are provided an electrostatic discharge (ESD) protection device having a first terminal and a second terminal. The ESD protection device comprises a vertical transistor having a collector coupled to the first terminal, a base, and an emitter coupled to the second terminal. A zener diode has a first terminal coupled to the first terminal of the ESD protection device and a second terminal coupled to the base of the vertical transistor. Subsurface current paths are provided to redistribute current from a surface of the vertical transistor in an ESD event. The method comprises generating an ionization current when a zener diode breaks down during an ESD event. The ionization current density from a surface zener diode region is reduced. The ionization current enables a transistor to dissipate the ESD event.

A system and method for controlling operation of a multiple cylinder internal combustion engine having fuel injectors and an ionization current sensor include a high-voltage power supply connectable to, and supplying substantially the same nominal boosted voltage relative to nominal battery voltage to, the fuel injectors and ionization sensor during at least a portion of the engine operation.

A low-frequency high AC voltage from an excitation voltage power source (14) is applied between one electrode (8) and two other electrodes (9A and 9B) to generate a low-frequency AC-excited dielectric barrier discharge within a gas passage (3), thereby creating atmospheric pressure non-equilibrium micro-plasma. A sample gas is mixed with hydrogen inside the passage of a nozzle (51), and further mixed with air outside an exit port (53) to burn, forming a hydrogen flame (57). Then, the sample gas reaches an ionization area (56), where the sample components are ionized due to the effect of light emitted from the plasma. Meanwhile, water molecules generated in the hydrogen flame (57) are supplied into the ionization area (56), whereby some of the sample-molecule ions are hydrated while the others undergo a reaction to form a hydroxonium ion. These kinds of hydrated ions have long lifetimes and barely become extinct halfway, so that they can efficiently reach a detection electrode (13) and be detected as ion current. As a result, the detection sensitivity is improved and the dynamic range is enhanced.

PCT No. PCT / SE97 / 01022 Sec. 371 Date Dec. 10, 1998 Sec. 102(e) Date Dec. 10, 1998 PCT Filed Jun. 11, 1997 PCT Pub. No. WO97 / 47875 PCT Pub. Date Dec. 18, 1997A method for generation of a low test voltage is used for the purpose of detecting an ionization current in the spark gap of an internal combustion engine. The voltage is generated by a controllable ignition magneto (5) arranged in order to charge (2) an ignition capacitor (4). The voltage is applied (3) to the primary side of the ignition device after generation of a spark and after the decay of the spark, after which the ionization current is detected (11) on the secondary side of the ignition device.

A flame rod drive signal generator and system for producing a flame rod drive signal for a flame rod of a combustion system. In one illustrative embodiment, the flame rod drive signal generator may include a voltage source, an input signal having a frequency, an LC oscillator and a drive mechanism. The drive mechanism may be powered by the voltage source, and may have an output coupled to the LC oscillator. The drive mechanism may receive the input signal, and produces a current in the LC oscillator that has a frequency that is related to the frequency of the input signal. The LC oscillator may then provide a flame rod drive signal to a flame rod that has an amplitude that is larger than the amplitude of the voltage source. In some cases, a controller may monitor the amplitude of the flame rod drive signal and adjust the frequency, duty cycle, or both, of the input signal to achieve a desired amplitude of the flame rod drive signal. Alternatively, or in addition, the controller may monitor an ionization current produced by the flame rod when the flame rod is subject to a flame.

A discharge ionization current detector capable of supplying plasma gas in large quantity to stabilize plasma simultaneously with lowering the sample dilution ratio to improve detection sensitivity is provided. A gas supply pipe 7 for supplying a plasma gas, which also functions as a dilution gas, is connected to a point near the connecting section of a first gas passage 3 having electrodes 4-6 for plasma generation and a second gas passage having electrodes 16 and 17 for ion detection. A first gas discharge pipe 8 is connected to the other end of the first gas passage 3, and a second gas discharge pipe 13 is connected to the other end of the second gas passage 11. Flow controllers 9 and 14 are provided in the gas discharge pipes 8 and 13, respectively. The flow rate of the gas passing through a plasma generation area and that of the gas passing through an ion current detection area can be independently regulated. Therefore, for example, it is possible to increase the former flow rate to stabilize the plasma and simultaneously decrease the latter flow rate to enhance the detection sensitivity for a low-concentration sample.

Air or gas cleaners enhance the uniformity of the current density between an emitter and one or more receptor electrodes by positioning one or more insulators or effective resistors between the emitter and the receptor electrode. Insulators and / or effective resistors are used to shield select portions, e.g. the edges of plate-type receptor electrodes, from ionization current flowing between an emitter and unshielded portions. This allows more compact structures without ionization current concentrations at the shielded regions, and results in lower ozone generation for a given particle collection efficiency.

A flame rod drive signal generator and system for producing a flame rod drive signal for a flame rod of a combustion system. In one illustrative embodiment, the flame rod drive signal generator may include a voltage source, an input signal having a frequency, an LC oscillator and a drive mechanism. The drive mechanism may be powered by the voltage source, and may have an output coupled to the LC oscillator. The drive mechanism may receive the input signal, and produces a current in the LC oscillator that has a frequency that is related to the frequency of the input signal. The LC oscillator may then provide a flame rod drive signal to a flame rod that has an amplitude that is larger than the amplitude of the voltage source. In some cases, a controller may monitor the amplitude of the flame rod drive signal and adjust the frequency, duty cycle, or both, of the input signal to achieve a desired amplitude of the flame rod drive signal. Alternatively, or in addition, the controller may monitor an ionization current produced by the flame rod when the flame rod is subject to a flame.

A discharge ionization current detector using a low-frequency barrier discharge is provided to improve the linearity of detection sensitivity with respect to a sample introduction amount. From a lower end of a lower gas passage 10 connected to a lower end of an upper gas passage 4, a dilution gas is supplied upward against a downward flow of a plasma gas. A gas discharge passage 15 for discharging a plasma gas, the dilution gas and a sample gas is arranged between an ion-collecting electrode 11 and a bias voltage application electrode 12. The sample gas introduced through a capillary tube 16 is mixed with the plasma gas and the dilution gas due to a disturbed flow generated by collision of the plasma gas and the dilution gas. The sample component is efficiently ionized by light from the plasma without undergoing light-shielding effect of concentrated sample components. Furthermore, since an ion generation area is close to the electrodes 11 and 12, ions can quickly move the short distance due to the action of a direct current electric field. Therefore, the ions can reach the ion-collecting electrode 11 before their lifetime terminates.

Provided is a discharge ionization current detector. To reduce the cost of a high-voltage power supply unit by reducing the discharge starting voltage for a low-frequency dielectric barrier discharge. Light from light source unit (20) located externally to cylindrical tube (2) through which a plasma gas (He) flows is irradiated through the wall surface of the cylindrical tube (2) onto a plasma generation region (the region between plasma generation electrodes (6 and 7) located in gas flow path (4). The light energy excites the He molecules or the minute quantities of impurity gas molecules present in the He gas, causing photo-ionization. This causes a discharge to start, and a plasma to be formed, when a low-frequency voltage of a voltage that is less than the usual discharge starting voltage is applied across electrode (5) and electrodes (6, 7). Once the discharge starts, the discharge is sustained when the usual discharge sustaining voltage is applied across electrode (5) and electrodes (6, 7). This means that the light source unit (20) has to be on only for a short duration when discharging is started.

A low-frequency high AC voltage from an excitation voltage power source (14) is applied between one electrode (8) and two other electrodes (9A and 9B) to generate a low-frequency AC-excited dielectric barrier discharge within a gas passage (3), thereby creating atmospheric pressure non-equilibrium micro-plasma. A sample gas is mixed with hydrogen inside the passage of a nozzle (51), and further mixed with air outside an exit port (53) to burn, forming a hydrogen flame (57). Then, the sample gas reaches an ionization area (56), where the sample components are ionized due to the effect of light emitted from the plasma. Meanwhile, water molecules generated in the hydrogen flame (57) are supplied into the ionization area (56), whereby some of the sample-molecule ions are hydrated while the others undergo a reaction to form a hydroxonium ion. These kinds of hydrated ions have long lifetimes and barely become extinct halfway, so that they can efficiently reach a detection electrode (13) and be detected as ion current. As a result, the detection sensitivity is improved and the dynamic range is enhanced.

The pressure in the combustion chamber of an electronically controlled spark plug ignition engine may be estimated in real time mode without specific sensors by processing sensed ionization current data to calculate features of the current waveform proven to be correlated to the pressure inside the engine cylinders and correlating them on the basis of a look up table of time invariant correlation coefficients generated through a calibration campaign of tests on a test engine purposely equipped with sensors. A mathematical model of the electrical and physical spark plug ignition system and combustion chamber of the engine is refined during calibration by iteratively testing the interactive performance of correlation coefficients of related terms of a mathematical expression of the model and comparing the expressed pressure value with the real pressure value as measured by a sensor.

The invention discloses a high-energy monomode plasma ignition system capable of detecting ionization, comprising a boosting transformer composed of a primary winding and a secondary winding; a single energy source connected with the primary winding, wherein the single energy source is a capacitor; a spark plug gap connected with the secondary winding, wherein the energy generated by the capacitor generates sparks in the spark plug gap after passing through the primary winding and the secondary winding; an additional circuit, wherein one end of the circuit is connected with the primary discharging end of the capacitor and the other end of the circuit is connected with the spark plug gap. The capacitance energy source can be used to generate primary high-voltage sparks and puncture the spark plug gap, and also provide subsequent currents to continue burning of the high-energy plasma arc. In comparison with the current ignition systems, the plasma ignition system combined with the ionization detection can produce needed high-energy sparks by just one capacitor to ignite gas-oil mixtures, and maintain the high voltage which generates the ionization current, and is convenient to be installed together with a coil ignition system on a spark plug. The plasma ignition system has advantages of small volume, high cost efficiency and so on.

A low-OH-content quartz glass having an OH content of 5 ppm or less is used as a cylindrical tube (2) for covering the surface of metal plasma-generating electrodes (4, 5, 6) in order to cause low-frequency barrier discharging. In low-frequency barrier discharging, hydrogen and oxygen from the OH included in a dielectric are released into the plasma over a prolonged period, and this was found to be the main cause of an increase in the baseline electric current. However, using a low-OH-content quartz glass allows the baseline electric current to be dramatically lowered, whereby the S / N ratio and detection limit can be improved.

A system and method for operating a multiple cylinder internal combustion engine having at least two spark plugs per cylinder include selectively isolating all but one spark plug associated with the cylinder at least during an ionization current sensing period to reduce or eliminate interference among ionization current signals flowing through more than one spark plug.

A discharge ionization current detector that is durable and produced at a low cost is provided. An electrode structure of a dielectric-coated metal tube, with an insulator-coated metal wire included therein, is inserted from above into a first gas passage including a dielectric tube. The metal tube is connected to the ground on the upstream side of the first gas passage. One end of the metal wire is extracted from the upstream side of the first gas passage to the outside and connected to a bias power source. An area is not covered with the insulator is provided at the other end of the wire. This area is arranged in a second gas passage, which extends from the downstream end of the first gas passage. A metal electrode consisting of a flanged metal tube is placed in the second gas passage and connected to an ionization current detecting circuit 34.

The invention discloses a gas type detecting method and system. The method comprises the following steps: enabling the multiwalled carbon nanotube integrated gas sensor to be connected in series with an amperemeter, a current-limiting resistor R1, and a sampling resistor R2 in sequence; under the action of a direct current high-voltage power supply, ionizing gas inside a cavity of the gas sensor; recording the voltage V between the electrodes of the sensor and the gas ionization current A of the sensor; analyzing detected data of the gas sensor by adopting a lyapunov index; judging the type of gas to be detected. The invention further discloses a preparation method for the multiwalled carbon nanotube integrated gas sensor. The gas type detecting method provided by the invention can realize the detection of different kinds of gas.

A discharge ionization current detector is provided with a dielectric tube through which plasma generating gas flows, a plasma generating unit formed from one section of the dielectric tube in a flow direction of the plasma generating gas, a casing connected to a lower end portion, in the flow direction of the plasma generating gas, of the dielectric tube, a sample ionization unit provided inside the casing, and an ion current detection unit for detecting a sample component ionized by the sample ionization unit. The lower end, in the flow direction of the plasma generating gas, of the dielectric tube protrudes into the space inside the casing.

The invention discloses an equivalent circuit and a simulation method for a high-voltage LDMOS device. In a high-voltage LDMOS device structure, the substrate current of a lightly-doped drift region is obviously different from that of the traditional intrinsic MOSFET, and a standard SPICE BSIM3 model is incapable of accurately simulating the substrate current of the lightly-doped drift region of the high-voltage LDMOS. According to the equivalent circuit and the simulation method disclosed by the invention, the collision ionization current of the lightly-doped drift region is accurately simulated by externally connecting a current source, a source equivalent resistor and a drain equivalent resistor, thus improving simulation accuracy and reducing a circuit design cycle.

An aging treatment is performed by using cleaning gas obtained by mixing inert gas, as an impurity, to plasma gas. Plasma generation by dielectric-barrier discharge is performed until a predetermined period of time has elapsed by applying high AC voltage to an electrode while supplying the cleaning gas to a dielectric tube from a gas inlet.

An adjusting method for a discharge ionization current detector of the present invention is provided for a discharge ionization current detector for a gas chromatograph, which improves the precision and reproducibility of measurements results of the detector. The discharge ionization current detector adjusts at least one of purity of introduced helium gas, a flow rate of the introduced helium gas, an amplitude of voltage of the low-frequency dielectric barrier discharge, and a frequency of the voltage of the low-frequency dielectric barrier discharge so that intensity of light having a wavelength of 640 nm reaches the maximum in a range of wavelengths of 250 to 700 nm with respect to light emitted by the helium plasma.

An ion source for an analytical instrument is described. The ion source comprises a capillary tip and counter-electrode interface and a feedback loop control device connected to the capillary tip and counter-electrode interface. The feedback loop control device comprises a transimpedance amplifier, a DC de-coupler, a frequency to voltage converter, a controller, and a voltage-controlled high-voltage power supply that provides a tip to counter-electrode voltage to the capillary tip and counter-electrode interface. The feedback loop control device measures the modulation frequency of ionization currents and provides a feedback adjustment of the tip-to-counter-electrode voltage to maintain ionization efficiency.

The invention relates to a discharge ionization current detector. A technique for reducing an electromagnetic noise entering an electrode or a drift of a signal due to a fluctuation in the ambient temperature is provided to improve the S / N ratio of a signal originated from a component of interest. A dummy electrode 11 having the same structure as an ion-collecting electrode 10 is provided within a lower gas passage 14 at a position where dilution gas with no sample gas mixed therein flows. A differential amplifier 24 is provided to perform differential detection between an output end A of a current amplifier 21 connected to the ion-collecting electrode 10 and an output end B of a current amplifier 22 connected to the dummy electrode 11. The detected differential signal is free from a common mode noise or a drift and hence accurately reflects the amount of the component of interest.

The invention belongs to the technical field of radiation monitoring and particularly relates to an automatic measurement system and method of an extrapolation ionization chamber. The system comprises an electrometer which is connected with the extrapolation ionization chamber, a direct-current power supply unit of the electrometer is connected with an electrode plate of the extrapolation ionization chamber and used for providing power for the extrapolation ionization chamber, a charge measurement unit of the electrometer is connected with a collector electrode of the extrapolation ionization chamber and used for measuring ionization current of the extrapolation ionization chamber, the electrometer is connected with a computer which is used for controlling performing of measuring operation, the extrapolation ionization chamber is provided with a counter electrode distance adjusting device, the counter electrode distance adjusting device is connected with a programmable logic controller (PLC), and the PLC is connected with the computer. According to the automatic measurement system and method of the extrapolation ionization chamber, the operation is simplified, measuring errors are reduced, and the measuring stability is improved.