529 results about "Trace gas" patented technology

A method for post-etch copper cleaning uses a hydrogen plasma with a trace gas additive constituting about 3-10 percent of the plasma by volume to clean a copper surface exposed by etching. The trace gas may be atomic nitrogen or other species having an atomic mass of 15 or greater. The trace gas adds a sputtering aspect to the plasma cleaning and removes polymeric etch by-products and polymeric and other residuals formed during the deposition of dielectric materials or etch stop layers over the copper surface. An anti-corrosion solvent may be used to passivate the copper surface prior to formation of the dielectric materials or etch stop layers.

A power plant including an air separation unit (ASU) arranged to separate nitrogen, oxygen, carbon dioxide and argon from air and produce a stream of substantially pure liquid oxygen, nitrogen, carbon dioxide and argon; a steam generator, fired or unfired, arranged to combust a fuel, e.g., natural gas, liquefied natural gas, synthesis gas, coal, petroleum coke, biomass, municipal solid waste or any other gaseous, liquid or solid fuel in the presence of air and a quantity of substantially pure oxygen gas to produce an exhaust gas comprising water, carbon dioxide, carbon monoxide, nitrogen oxides, nitrogen, sulfur oxides and other trace gases, and a steam-turbine-generator to produce electricity, a primary gas heat exchanger unit for particulate / acid gas / moisture removal and a secondary heat exchanger arranged to cool the remainder of the exhaust gases from the steam generator. Exhaust gases are liquefied in the ASU thereby recovering carbon dioxide, nitrogen oxides, nitrogen, sulfur oxides, oxygen, and all other trace gases from the steam generator exhaust gas stream. The cooled gases are liquefied in the ASU and separated for sale or re-use in the power plant. Carbon dioxide liquid is transported from the plant for use in enhanced oil recovery or for other commercial use. Carbon dioxide removal is accomplished in the ASU by cryogenic separation of the gases, after directing the stream of liquid nitrogen from the air separation unit to the exhaust gas heat exchanger units to cool all of the exhaust gases including carbon dioxide, carbon monoxide, nitrogen oxides, nitrogen, oxygen, sulfur oxides, and other trace gases.

The invention discloses a hollow anti-resonance optical fiber, and belongs to the technical field of optics and laser photoelectrons.The basic structure of the hollow anti-resonance optical fiber comprises a fiber core area with low refraction rate and a wrapping layer area with high refraction rate.The wrapping layer area with high refraction rate is divided into an inner wrapping layer region and an outer wrapping layer region.The inner wrapping layer region is composed of one or two layers of micro capillary pipes.The fiber core area with low refraction rate is wrapped by the inner wrapping layer region.Compared with a traditional band gap type hollow-core photonic crystal fiber, the hollow anti-resonance optical fiber has the advantages of being large in spectral bandwidth, small in bending loss, low in transmission loss, high in damage threshold and capable of keeping single-modulus transmission.A high-efficiency and high-sensitivity ideal platform is created for nonlinear frequency conversion, trace gas / liquid detection, high-power pulse compression and other foremost application.

A method of reducing pollutants exhausted into the atmosphere from the combustion of fossil fuels. The disclosed process removes nitrogen from air for combustion, separates the solid combustion products from the gases and vapors and can capture the entire vapor / gas stream for sequestration leaving near-zero emissions. The invention produces up to three captured material streams. The first stream is contaminant-laden water containing SOx, residual NOx particulates and particulate-bound Hg and other trace contaminants. The second stream can be a low-volume flue gas stream containing N2 and O2 if CO2 purification is needed. The final product stream is a mixture comprising predominantly CO2 with smaller amounts of H2O, Ar, N2, O2, SOX, NOX, Hg, and other trace gases.

A leak detection system includes a trace gas leak detector having a wireless base unit, and a handheld wireless remote unit to generate an alphanumeric display of leak rate measured by the leak detector, in response to leak detector information received by wireless link from the leak detector. The remote unit may include a wireless transceiver to communicate with the wireless base unit of the leak detector, a display unit and a controller, responsive to the received leak detector information, to generate the display on the display unit. The remote unit may be configured to control the leak detector and may be configured to display a leak detector operating mode.

Methods and apparatus for broad tuning of single wavelength quantum cascade lasers and the use of light output from such lasers for highly sensitive detection of trace gases such as nitrogen dioxide, acetylene, and vapors of explosives such as trinitrotoluene (TNT) and triacetone triperoxide (TATP) and TATP's precursors including acetone and hydrogen peroxide. These methods and apparatus are also suitable for high sensitivity, high selectivity detection of other chemical compounds including chemical warfare agents and toxic industrial chemicals. A quantum cascade laser (QCL) system that better achieves single mode, continuous, mode-hop free tuning for use in L-PAS (laser photoacoustic spectroscopy) by independently coordinating gain chip current, diffraction grating angle and external cavity length is described. An all mechanical method that achieves similar performance is also described. Additionally, methods for improving the sensor performance by critical selection of wavelengths are presented.

Compact tunable optical cavities are provided for in-situ NIR spectroscopy. MEMS-tunable VCSEL platforms represents a solid foundation for a new class of compact, sensitive and fiber compatible sensors for fieldable, real-time, multiplexed gas detection systems. Detection limits for gases with NIR cross-sections such as O2, CH4, COx and NOx have been predicted to approximately span from 10ths to 10s of parts per million. Exemplary oxygen detection design and a process for 760 nm continuously tunable VCSELS is provided. This technology enables in-situ self-calibrating platforms with adaptive monitoring by exploiting Photonic FPGAs.

The invention discloses an infrared cavity ring-down spectroscopy trace gas detection method based on quantum cascade laser; comprising the following steps: using a tunable quantum cascade laser as alight source, and selecting measuring waveband and wavelength scan step length aiming at spectrum line characteristic of the gas to be detected; respectively measuring the cavity ring-down time of each wavelength in the cavity with absorption or without absorption by cavity ring-down technique, and calculating the gas absorption coefficient of corresponding wavelength so as to obtain a relation curve that is an absorption spectrogram of the measured gas absorption coefficient and toned laser wavelength. The spectrogram is contrasted with spectrum line characteristic of corresponding gas in HITRAN database, thereby being capable of analyzing and determining weather the measured gas contains the predetermined gas component; the absolute concentration of the gas to be measured can be calculated and obtained and the absolute concentration of the gas to be measured can be measured through scaling measurement by using absorption peak wavelength of the absorption spectrum as the best detection wavelength and the relation among the gas absorption coefficient of the wavelength, the absorption cross section and concentration. The method has high measuring sensitivity and high property of resisting interference so that the fast and exact on-line analysis and detection of multiple trace gases are easily realized.

The invention discloses a trace gas detection device and a trace gas detection method based on an intermediate infrared quantum cascade laser direct absorption spectrum method. A tunable quantum cascade laser serves as a light source, and concentration information of gas molecules to be measured is acquired by utilizing fundamental frequency fingerprint absorption characteristics of the gas molecules in an intermediate infrared wave band; the measured result is slightly influenced by light-intensity variation of the laser and has higher signal to noise ratio and certain anti-jamming capability by utilizing a direct absorption spectrum technology; and whether the measured gas contain expected gas components can be analyzed and determined by contrasting the measured spectrum with spectral line characteristics of corresponding gas in a HITRAN database, and concentration inversion is performed by utilizing spectral line parameters provided by the HITRAN database. The system is simple and compact in structure and convenient to use and maintain, has the characteristics of high measuring sensitivity, high accuracy and high response speed, can rapidly and accurately analyze and detect a plurality of trace gases and isotope ratios on line, and can be used for indicating and rapidly and accurately positioning intermediate infrared light spots.

An apparatus and method are used to enhance the sensitivity of a spectrometer (sensor) for trace gas species detection by employing an external cavity continuously tunable CW quantum cascade laser and integrating the absorption spectra across multiple lines of the species. With this method the absorption spectra of NO2 is continuously recorded across the R-branch from 1628.8 cm−1 to 1634.5 cm−1. By integrating the resulting spectra, the detection sensitivity for NO2 is improved by a factor of 15 compared to the sensitivity achieved using single line laser absorption spectroscopy with the same apparatus. This procedure offers much shorter data acquisition times for the real-time monitoring of trace gas species compared with adding repeated scans of the spectra to improve the signal-to-noise ratio.

The invention relates to a method and a device for detecting gas, in particular to a modulation spectrum gas detection method based on quasi-continuous diode laser, and a device thereof. The invention adopts a technical proposal that a quasi-continuous diode laser spectrum modulation method for gas detection comprises the following steps: a modulation signal generator outputs a modulation signal and a reference signal; the modulation signal is supplied to a laser driver for controlling the injection current of a quasi-continuous diode laser; the reference signal is supplied to a lock-in amplifier and used as the reference signal; laser emitted by the quasi-continuous diode laser passes through to-be-detected gas and then is received by a photodetector; the output of the photodetector is transmitted to a preamplifier, amplified and then sent into the lock-in amplifier; and output signals of the lock-in amplifier are sent into a computer via an AD converter, processed and analyzed, so as to obtain the species and concentration data of the detected gas. The method is mainly applied to occasions needing trace gas detection with high sensitivity and high resolution.

A sensor system featuring a field angle compression telescope optical system for measuring atmospheric trace gases is provided. According to an embodiment of the present invention, the telescope optical system condenses the field angle of received light with respect to a cross track plane, while leaving the field angle with respect to an along-track plane uncompressed. Such an anamorphic telescope design provides a wide field of view, while allowing information regarding the altitude or height distribution of a gas to be obtained. According to another embodiment of the present invention, the field angle of received light is compressed by magnifying the received light by a value less than 1.0 in all directions.

Methods and apparatus for broad tuning of single wavelength quantum cascade lasers and the use of light output from such lasers for highly sensitive detection of trace gases such as nitrogen dioxide, acetylene, and vapors of explosives such as trinitrotoluene (TNT) and triacetone triperoxide (TATP) and TATP's precursors including acetone and hydrogen peroxide. These methods and apparatus are also suitable for high sensitivity, high selectivity detection of other chemical compounds including chemical warfare agents and toxic industrial chemicals. A quantum cascade laser (QCL) system that better achieves single mode, continuous, mode-hop free tuning for use in L-PAS (laser photoacoustic spectroscopy) by independently coordinating gain chip current, diffraction grating angle and external cavity length is described. An all mechanical method that achieves similar performance is also described. Additionally, methods for improving the sensor performance by critical selection of wavelengths are presented.

A spectroscopic sensor and a spectroscopic method of determining a concentration of a sample are disclosed. The sensor is used in connection with a sample cell containing a sample. The sensor includes a coherent light source configured to transmit an interrogation light beam along an optical sample path directed towards the sample. The sensor also includes an in-line reference cell located in the sample path. The sensor also includes a detector having outputs responsive to absorption signals from the sample and the in-line reference cell. The sensor also includes a processor configured to isolate the reference absorption signals from the in-line reference cell and sample absorption signals from the sample cell and generate calibration information based on the reference absorption signals and determine a concentration of the sample based on the sample absorption signals.

The invention relates to a cavity enhanced absorption spectrum device and method for simultaneous measurement of trace gas concentration and aerosol extinction. The LED temperature is controlled by a semiconductor refrigeration chip to ensure the stability of light intensity output. High reflectivity mirrors at both ends of an optical cavity have the same curvature radius and reflectivity greater than 99.9%, and compose a stable optical resonator. Usually, cavity enhanced absorption spectrum measures the light intensity in the cavity with or without gas absorption and the variation curve of the high reflectivity mirrors' lens reflectivity along with the wavelength, and finally the concentration of absorption gas in the cavity can be obtained. The device and the method provided by the invention can realize simultaneous measurement of trace gas concentration and aerosol extinction. The actual measured total absorption coefficient is divided into two parts, one part is a trace gas absorption structure changing rapidly along with the wavelength, and the other part is gas scattering and aerosol extinction coefficient changing slowly along with the wavelength. Nonlinear least-square fitting is carried out on the measured total absorption coefficient to calculate the concentration of the to-be-measured trace gas, and finally the gas absorption structure and gas scattering are deducted from the total absorption coefficient so as to obtain the aerosol extinction coefficient.

The invention discloses the field of dynamic characteristic research for interaction of laser and atmosphere in spectrum detection for trace gas and free-space optical communication, and particularly relates to an automatic tunable system with multiple optical paths. The automatic tunable system comprises angle rotating devices, length adjusting devices, supports, motor supports, stepper motors, a DSP (digital signal processor) controller and a cylindrical main body. The main body can keep vacuum and can bear certain high pressure. Signals are inputted into the DSP controller according to requirements of the optical paths, rotational angles of concave reflectors and required voltage are computed by the DSP controller, piezoelectric transistors (PZT) can drive the concave reflectors to rotate by the rotational angles after being supplied with the required voltage, signals are outputted for triggering and driving to realize automatic angular rotation, simultaneously, the stepper motors are driven, corrugated pipes are driven to stretch or contract, and distances d among reflecting pools are horizontally increased or reduced. The automatic tunable system with the multiple optical paths has the advantages of high precision and sensitivity, simplicity in operation and automatic control function.

The invention discloses a system for quantificationally collecting trace gas in a rock group inclusion and a use method thereof, pertaining to the experimental field of geochemical investigation field. The system consists of a rock sealing and milling unit, a trace gas transfer unit and a trace gas metering unit, wherein a gas storage metering tube 503 and a water storage tube 504 in the trace gas metering unit are made of glass and a gas extraction screw nut 502 is made of organic glass and other plastics; the gas storage metering tube 503 has small inside diameters, uniform upper and lower inside diameters and the maximum internal volume of 500 microliters or 1,000 microliters, and the external of the gas storage metering tube is provided with scales (the measuring unit is microliter); the center section of the water storage tube 504 takes the shape of a drum; and a sealing gasket 501 is a solid cylindrical plate made from silastic. The invention solves the problems that trace gas can not be taken for analysis in a closed container under a low negative pressure status, transfer collection is uncompleted, gas is inconvenient to be taken for analysis and sequent quantitative and qualitative analyses on a plurality of items can not be carried out simultaneously in the prior art.

The invention discloses a micro optical fiber gas sensor covered by adopting graphene and relates to the field of gas sensors, in particular relates to the field of an optical fiber intermodal interference sensor. A micro optical fiber which is drawn to have two thick ends and thin middle through a fused biconical taper method is arranged on a magnesium fluoride substrate, a single-layer graphene material covers the middle section of the micro optical fiber, and because the single-layer graphene material is extremely sensitive to chemical bonds between atoms and an extranuclear electron state is extremely sensitive to an ambient environment, distribution of a dielectric constant is changed due to contact between the material and trace gas molecule, so that the optical refractive index is changed, and finally the intermodal interference spectrum of light propagated in the optical fiber is changed, the gas types are identified by detecting the interference spectrum, and the aims of the gas sensor are achieved. Therefore, the micro optical fiber gas sensor has the advantages of small size, high precision, high sensitivity, stability in operation and repeated utilization effect.

A trace gas sensing apparatus includes a cathode, an anode, a vacuum enclosure, and a membrane. The anode coaxially surrounds the cathode, wherein the cathode and the anode define an annular ionization chamber. The vacuum enclosure surrounds the cathode and the anode and includes a gas inlet fluidly communicating with the ionization chamber. The membrane is coupled to the gas inlet in a sealed manner and is permselective to trace gas. The apparatus may further include circuitry for applying a negative voltage potential to the cathode and for measuring an ion current signal generated by the cathode, and a magnet assembly for generating a magnetic field in the ionization chamber. The cathode may include an elongated member located along a longitudinal axis, and first and second end plates orthogonal to the longitudinal axis.

A photo acoustic trace gas detector (100) is provided for detecting a concentration of a trace gas in a gas mixture. The photo acoustic trace gas detector (100) comprises a light source (101), an optical cavity (104a, 104b), ratio modulating means (105, 111) and a transducer (109). The optical cavity (104a, 104b) contains the gas mixture and amplifies light intensity. Maximum amplification is provided when a ratio of a wavelength of the light beam and a length of the optical cavity (104a, 104b) has a resonance value. Ratio modulating means (105, 111) modulate the ratio for transformation of the light beam into a series of light pulses for generating the sound waves, an amplitude of the sound waves being a measure of the concentration of the trace gas. A transducer (109) converts the sound waves into electrical signals.

A sensor with high sensitivity and selectivity for the detection of NO2 uses a simple diode laser operating nominally at 405 nm in the visible region, a high finesse optical cavity and a low noise photon detector. The sensor employs the multimode broad output of the diode laser with the high finesse optical cavity in an essentially off-axis arrangement that can provide large path lengths of the order of a km in a small volume cell. The detected absorption signal corresponds to multiple line integrated absorption spectroscopy (MLIS). Because the sensor uses visible radiation it can employ optics in the visible region that are normally less expensive. Also, the sensor is free from interference from atmospheric water vapor which is often a severe problem for sensors based on mid-infrared quantum cascade lasers operating in the mid-infrared (for example 1650 cm−1) region.

The invention relates to an optoacoustic spectroscopy multi-ingredient trace gas detection instrument and method, and belongs to the technical field of trace gas detection. The instrument comprises amedium infrared heat radiation light source, a light gathering mirror, a chopper, an optical filter plate group, an optoacoustic pool, a laser light source, an optical collimator, an air inlet valve,an air outlet valve, a microphone, a control and signal processing circuit and a touch screen, wherein the medium infrared heat radiation light source is longitudinally coupled to the optoacoustic pool after the light gathering; the optoacoustic signals are measured by using the intensity modulation-base wave detection technology; the laser is coupled into the optoacoustic pool from the side surface and is reflected for many times on the surface of the pool wall; the optoacoustic signals are measured by using a wave-length modulation-second harmonic detection technology; the background noise interference is greatly reduced. The advantages, suitable for multi-ingredient gas measurement and realizing high detection sensitivity, of the optoacoustic spectroscopy method of the medium infrared heat radiation light source and the laser optoacoustic spectroscopy method are sufficiently used; the technical complementation is realized; the technical scheme with good competitiveness is provided for the high-sensitivity detection of the multi-ingredient trace gas.

A time-resolved spectroscopy system employing a time-division multiplexing optical device with no dispersive optical elements to perform lifetime and concentration measurements in multi-species samples, is disclosed. Some examples include fluorescence and cavity ring-down spectroscopy. The system is unique in its compactness and simplicity of operation. In one embodiment, the system makes use of only one photo-detector and an efficient linear regression algorithm. The system offers a measurement time for multiple species measurements of less than 1 s. The system can also be used to perform fluorescence correlation spectroscopy and fluorescence cross-correlation spectroscopy. Four methods to de-convolve a multi-component, exponentially decaying optical signal such as obtained with the system disclosed here, are presented. These methods may be applied to the measurement of fluorescence decay lifetimes and cavity ring-down times, the latter used extensively for the measurement of gas and trace-gas concentrations in complex mixtures, via absorption spectroscopy.

The invention relates to a portable device for remotely measuring atmospheric pollution components day and night on the basis of a natural celestial body light source, which comprises a two-dimensional rotating platform system with a celestial body tracking function, a telescope system, a spectrometer and a computer. Received directly irradiated sunlight, moonlight, starlight and scattered sunlight are transmitted to the spectrometer by the telescope system through an optical fiber; spectral information acquired by the spectrometer is transmitted to the computer through AD (analog-to-digital) conversion; and the inversion is carried out by utilizing a related algorithm through the computer so as to obtain a vertical column concentration and vertical column distribution information of atmospheric trace gas. After the portable device for remotely measuring the atmospheric pollution components day and night is adopted, the day and night monitoring on the atmospheric conventional pollutant gas can be realized; and under the condition that any artificial light source is not required, a telescope is driven by a rotating platform to track a celestial body or carry out directional scanning so as to complete measuring a pollutant gas absorption spectrum. Compared with other optical methods, the portable device for remotely measuring the atmospheric pollution components day and night has the advantages that the portable device has simple system structure, is simple to assemble and disassemble and is convenient to carry; the day and night continuous measurement can be realized; and the vertical column concentration and the vertical column distribution information of the trace gas are obtained.

A non-contact, extractive sampling system and method is provided for measuring the exhaust gas and fine particle composition of various types of vehicles under actual operating conditions. A portion (or sample) of an exhaust plume of a vehicle is pulled or extracted through an extraction sampling tube, via a vacuum pump, to a remote trace gas detection system where the concentration of one or more constituents present in the sample of exhaust plume may be measured. In this regard, the invention enables vehicle emissions measurements to be made at a location remote from roadway, rather than using known, “cross-path” remote emissions sensing systems.

The invention relates to a system for automatically acquiring and analyzing a trace gas, which comprises a central control computer, an industrial control module group, a sampling part and a gas acquisition and analysis part, wherein the central control computer is used for writing programs by means of industrial control configuration software, generating and transmitting tank cover, gas passage and gas analysis commands, and receiving and storing analog signals which contain environmental meteorologic parameters and trace gas concentration data and are transmitted by the industrial control module group; the industrial control module group is respectively connected with the central control computer, the sampling part and the gas acquisition and analysis part; the gas acquisition and analysis part is connected with a pipeline of the sampling part; the industrial control module group is used for receiving industrial control commands, outputting multiple switching signals, and controlling the sampling part and the gas acquisition and analysis part to automatically carry out tank cover switching, gas acquisition and trace gas concentration analysis according to the programs; and the industrial control module group is used for processing current signals output by the sampling part and voltage signals output by the gas acquisition and analysis part and outputting the analog signals containing the environmental meteorologic parameters and the gas concentration data.