The present invention discloses a method of infrared spectrometric measurement of tunnel gas employing a gas measurement system including a gas collection unit, a gas analysis unit and a positioning indication unit for measuring the gas in the tunnel. The method performs sequential steps of installing the gas measurement system, starting the positioning indication unit for positioning one of the detection regions in the tunnel space, sampling the gas in the detection region through the gas collection unit, analyzing the gas by the gas analysis unit, generating a gas analysis result, and determining whether all of the detection regions are completed. With the newly designed gas collection unit in collocation with the gas analysis unit and the positioning indication unit, the method of the present invention does not only fast install the whole gas measurement system, but also well understands all preliminary information related to the harmful gas in the tunnel like sort and concentration, thereby instantly taking correct measures.

A device for measuring oxygen saturation includes circuitry configured to determine a series resistance for a light emitting diode based on a first diode voltage at the light emitting diode for a first current, a second diode voltage at the light emitting diode for a second current, and a third diode voltage at the light emitting diode for a third current. The circuitry is further configured to determine an intensity of a received photonic signal corresponding to an output photonic signal output using the light emitting diode. The circuitry is further configured to determine an oxygen saturation level based on the intensity of the received photonic signal and the series resistance.

The present invention has as its object the provision of a methane number calculation method that allows for readily acquiring a methane number of a natural gas, which is a sample gas to be measured, with acceptable reliability irrespective of toe gas composition, and as another object the provision of a methane number measurement device that is capable of monitoring the fuel property of a natural gas to be used as a fuel gas.

The present invention includes: acquiring in advance a particular relational expression between the methane number and the basic calorific value of a plurality of types of reference gases, each formed of a natural gas and each having a different methane number value; measuring the basic calorific value of a natural gas, which is a sample gas, as well as the concentration of the nitrogen gas and the concentration of the carbon dioxide gas, both gases being contained in the sample gas; and calculating the methane number of the sample gas from the value of the basic calorific value of the sample gas, the value of the concentration of the nitrogen gas and the value of the concentration of the carbon dioxide gas, and the particular relational expression.

A method of detecting natural gas releases that includes the step of traversing a target area with a gas-filter correlation radiometer having a field of view oriented towards the target area. The gas-filter correlation radiometer receives reflected radiation in a passband from the target area and produces gas-filter correlation radiometer signals from the received reflected radiation. A surface reflectivity spectral profile of the target area is determined. The presence of methane in the target area is then determined based upon the received reflected radiation and the surface reflectivity spectral profile of the target area.

A cavity enhanced absorption spectroscopy (CEAS) system is provided that utilizes collimators the incorporate gradient index (GRIN) lenses in lieu of conventional spherical or aspheric refractive lenses. The use of smaller diameter GRIN lenses facilitates a reduced initial beam size entering the sample cavity, which reduces self-interference noise and increases a signal to noise ratio of the measurements. Further, a reduced size and mass of the GRIN lens can reduce a size of the mounting hardware utilized to mount the optical components, which enables more laser beams to be coupled to a single gas cell compared to a similar gas cell integrated with conventional refractive collimators. A larger number of lasers enables more gas peaks to be measured substantially simultaneously using the CEAS system.

Provided is a gas sensor that can suppress characteristic variation caused by deformation of a semiconductor substrate. The gas sensor (1) includes a substrate (redistribution layer 30), a light-emitting element (11) provided at a front surface (30a) or embedded in the substrate, a light-receiving element (12) that is provided at the front surface or embedded in the substrate and that receives light emitted from the light-emitting element, and a plurality of external connection terminals (40) at a rear surface (30b) that is an opposite surface to the front surface of the substrate. At least a portion of the plurality of external connection terminals is electrically connected to the light-emitting element and the light-receiving element. The plurality of external connection terminals is arranged such that, in plan view, the light-emitting element and the light-receiving element are not present on a line linking any two external connection terminals.

An integrated optical sensor enables the detection and identification of one or more remote gases using a transmission filter that matches specific absorption features of a remote gas and is detected using a single photodetection element. The sensor comprises an integrated optical component that is characterized by its transmission spectrum which corresponds to absorption or emission features of a target gas over a defined spectral bandpass, and the ability to have a reversibly tunable transmission spectrum. The change in the optical power output from the sensor as the transmission spectrum is tuned is proportional to the optical depth of the target gas absorption lines when viewed with a background light source. The optical power output from the integrated optical component is therefore related to the absorption spectrum of the input light Physical properties of the sensor are tailored to produce a quasi-periodic transmission spectrum that results in a stronger signal contrast for a specific gas. The sensor is preferably a waveguide ring resonator with a free spectral range that matches the absorption spectrum of a gas over a finite spectral bandpass.

An integrated optical sensor enables the detection and identification of one or more remote gases using a transmission filter that matches specific absorption features of a remote gas and is detected using a single photodetection element. The sensor comprises an integrated optical component that is characterized by its transmission spectrum which corresponds to absorption or emission features of a target gas over a defined spectral bandpass, and the ability to have a reversibly tunable transmission spectrum. The change in the optical power output from the sensor as the transmission spectrum is tuned is proportional to the optical depth of the target gas absorption lines when viewed with a background light source. The optical power output from the integrated optical component is therefore related to the absorption spectrum of the input light Physical properties of the sensor are tailored to produce a quasi-periodic transmission spectrum that results in a stronger signal contrast for a specific gas. The sensor is preferably a waveguide ring resonator with a free spectral range that matches the absorption spectrum of a gas over a finite spectral bandpass.

An analyzer analyzes a measurement sample on the basis of spectrum data obtained by irradiating light to the measurement sample. The analyzer includes a main analysis part, a correlation data storage part and a concentration calculation part. The main analysis part calculates a concentration of a predetermined hydrocarbon component contained in the measurement sample on the basis of the spectrum data of the measurement sample. The correlation data storage part stores therein a plurality of correlation data each indicating a correlation between a concentration of the predetermined hydrocarbon component or the spectrum data and a THC concentration. The concentration calculation part selects at least one correlation data from among a plurality of correlation data stored in the correlation data storage part according to the concentration of the predetermined hydrocarbon component, and calculates a concentration of the total hydrocarbon components in the measurement sample by using correlation data thus selected.

A device for measuring oxygen saturation includes circuitry configured to determine a series resistance for a light emitting diode based on a first diode voltage at the light emitting diode for a first current, a second diode voltage at the light emitting diode for a second current, and a third diode voltage at the light emitting diode for a third current. The circuitry is further configured to determine an intensity of a received photonic signal corresponding to an output photonic signal output using the light emitting diode. The circuitry is further configured to determine an oxygen saturation level based on the intensity of the received photonic signal and the series resistance.