Systems and methods for measuring the isotope ratio of one or more trace gases and/or components of gas mixtures such as different gas species present in a gas mixture. The system includes a resonant optical cavity having two or more mirrors and containing a gas, the cavity having a free spectral range that equals the difference between frequencies of two measured absorption lines of different gas species in the gas, or of two different isotopes, divided onto an integer number. The system also includes a continuous-wave tunable laser optically coupled with the resonant optical cavity, and a detector system for measuring an absorption of laser light by the gas in the cavity. The detector system includes one of a photo-detector configured to measure an intensity of the intra-cavity light or both a photo-acoustic sensor configured to measure photo-acoustic waves generated in the cavity and a photo-detector configured to measure an intensity of the intra-cavity light.

Described herein is a spectroscopic system and method for measuring and monitoring the chemical composition and/or impurity content of a sample or sample stream using absorption light spectroscopy. Specifically, in certain embodiments, this invention relates to the use of sample pressure variation to alter the magnitude of the absorption spectrum (e.g., wavelength-dependent signal) received for the sample, thereby obviating the need for a reference or zero sample. Rather than use a reference or zero sample, embodiments described herein obtain a spectrum/signal from a sample-containing cell at both a first pressure and a second (different) pressure.

Devices to detect a substance and methods of producing such a device are disclosed. An example device to detect a substance includes a housing defining an externally accessible chamber and a seal to enclose at least a portion of the chamber. The example device also includes a substrate includes nanoparticles positioned within the chamber. The nanoparticles to react to the substance when exposed thereto. The example device also includes a non-analytic solution within the chamber to protect the nanoparticles from premature exposure.

Method and apparatus testing engine component, for blockage of one or more through-holes in a portion of a wall. The method including (i) providing a supply of test fluid, (ii) causing or permitting flow of test fluid to occur from first to second region, (iii) illuminating the second region with electromagnetic radiation to cause scattering of electromagnetic radiation by material exiting substantially non-blocked through-holes in wall portion having passed therethrough from the first to second side, (iv) detecting said scattering of electromagnetic radiation from said substantially non-blocked through-holes; and (v) comparing said detected scattering of electromagnetic radiation from said substantially non-blocked holes with known pattern of through-holes in component wall portion to determine the presence and/or location and/or identity of any blocked or partially blocked through-holes in component wall portion.

A closed path infrared sensor includes an enclosure, a first energy source within the enclosure, at least a second energy source within the enclosure, at least one detector system within the enclosure and a mirror system external to the enclosure and spaced from the enclosure. The mirror system reflects energy from the first energy source to the at least one detector system via a first analytical path and reflects energy from the second energy source to the at least one detector system via a second analytical path. Each of the first analytical path and the second analytical path are less than two feet in length.

Systems and methods for measuring the isotope ratio of one or more trace gases and/or components of gas mixtures such as different gas species present in a gas mixture. The system includes a resonant optical cavity having two or more mirrors and containing a gas, the cavity having a free spectral range that equals the difference between frequencies of two measured absorption lines of different gas species in the gas, or of two different isotopes, divided onto an integer number. The system also includes a continuous-wave tunable laser optically coupled with the resonant optical cavity, and a detector system for measuring an absorption of laser light by the gas in the cavity. The detector system includes one of a photo-detector configured to measure an intensity of the intra-cavity light or both a photo-acoustic sensor configured to measure photo-acoustic waves generated in the cavity and a photo-detector configured to measure an intensity of the intra-cavity light.

A microscopy observation method for fluorescence observation of a sample including an object to be observed containing a fluorescent material using a microscope apparatus, including an excitation light emission step of emitting excitation light for exciting the fluorescent material contained in the sample; and an oxygen concentration reduction step of reducing the oxygen concentration at least in an observed region in which the sample is present.

Disclosed are a molecular imaging method using Raman spectra and system based on machine learning cascade. The system includes a coordinate localization module, a hierarchical clustering analysis module, a Raman predictive imaging module, and a similarity analysis module. An untreated frozen tissue slice is attached to a stainless steel slide, and an adjacent slice is attached to a glass slide. The coordinate localization module can match a Raman white light image of a detection sample attached to the stainless steel slide with an immunohistochemistry (IHC) image of the adjacent slice, such that Raman spectra of a target region are accurately collected. The hierarchical clustering analysis module purifies different types of Raman spectra. A machine learning classifier is configured to build a Raman predictive imaging model. The similarity analysis module can evaluate similarity between a predicted Raman predictive image and the IHC image of the adjacent slice.

Analytic sensors and methods utilize an attenuated total reflection (ATR) crystal to detect volatile compounds in an arrangement that reduces interference from compounds other than the one of interest. In particular, the components in the measurement stream are limited to those having volatilities close to that of the analyte of interest, which may be identified based on, for example, the temperature of the ATR crystal and the dwell timei.e., an interval of substantially constant temperature as the ATR crystal is heated.

Described herein is a spectroscopic system and method for measuring and monitoring the chemical composition and/or impurity content of a sample or sample stream using absorption light spectroscopy. Specifically, in certain embodiments, this invention relates to the use of sample pressure variation to alter the magnitude of the absorption spectrum (e.g., wavelength-dependent signal) received for the sample, thereby obviating the need for a reference or zero sample. Rather than use a reference or zero sample, embodiments described herein obtain a spectrum/signal from a sample-containing cell at both a first pressure and a second (different) pressure.