527 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.

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 SO_x, residual NO_x 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, SO_X, NO_X, Hg, and other trace gases.

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, CO_x and NO_x have been predicted to approximately span from 10^ths 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.

The invention discloses mid-infrared spectroscopy-based trace gas detection method and device combining a long-optical-path open light path with a wavelength modulation technique. The detection device mainly consists of a continuous wave quantum cascade laser (CW-QCL), a laser driving and controlling unit, a plane mirror, a beam splitter, a visible laser, a reference gas pool, mercury, tellurium and cadmium (MCT) detector, an off-axis parabolic mirror, a corner reflector, a digital lock-in-amplifier and a computer. By using the CW-QCL as a light source, long-optical-path open light path is combined with the wavelength modulation technique to detect multi-component trace gas with high sensitivity.

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.

In spectroscopic devices the sections of an optical measuring path from a light source to a measuring volume containing a measuring gas and from there to a measuring detector are often sealed off from the ambient atmosphere and purged with a purge gas such as dry nitrogen to prevent penetration of atmospheric gas components, such as water vapor, which may interfere with the trace gas measurement. The moisture content in the nitrogen supply is usually in the range of a few ppm at the gas source and can increase dramatically at the measuring site depending on the length of the nitrogen pipe net and due to porosity of the pipe walls, leakage of seals and residual moisture trapped in so-called dead legs. In order to compensate interfering absorption of atmospheric gas components and other impurities in the purge gas the purge gas is collected after flushing the optical path sections, a portion of the light of the light source is transmitted along a second optical path to a compensation detector, the second optical path is flushed with the collected purge gas and the trace gas component in the measuring gas is determined based on a difference between the output of the measuring detector and the output of the compensation detector.

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.