267 results about "Atomic absorption spectroscopy" patented technology

An integrated-cavity output spectroscopy (ICOS) instrument adapted for measuring liquid samples has a low-scatter flow cell arrangement passing through a stable optical cavity defined by an arrangement of two or more mirrors. The flow cell provides a sample volume within the cavity of at most one microliter at any given time. The optical cavity has an effective cavity length of at most one centimeter and mirror radii of curvature for the stable cavity arrangement are much longer than the cavity length. A light beam with stable characteristics is introduced into the cavity, passes through the liquid sample cell multiple times, and a detector measures a portion of the light from the cavity. The light measurement is analyzed to determine absorption by the liquid sample, and related information.

Systems and methods for chip-integrated label-free detection and absorption spectroscopy with high throughput, sensitivity, and specificity are disclosed. The invention comprises packaged chips for multiplexing photonic crystal waveguide and photonic crystal slot waveguide devices. Other embodiments are described and claimed.

Quartz member such as a quartz tube for semiconductor manufacturing equipment capable of heat treating a substrate to be treated without causing contamination, a manufacturing method of such quartz member, thermal treatment equipment furnished with such quartz member, and an analysis method of metal in quartz member are provided. A quartz specimen is immersed in hydrofluoric acid to expose a layer to be analyzed located at a prescribed depth. On an exposed surface, a decomposition liquid such as hydrofluoric acid or nitric acid is dripped to decompose only an extremely thin layer to be analyzed, followed by recovering of the decomposition liquid. The decomposition liquid is quantitatively analyzed by use of atomic absorption spectroscopy (AAS) or the like to measure an amount of metal contained in the decomposition liquid. From a difference of thicknesses before and after the decomposition and an area of dripped decomposition liquid, a volume of a decomposed layer to be analyzed is obtained. From this and the amount of metal contained in the decomposition liquid, a concentration of metal contained in the layer to be analyzed, in addition a diffusion coefficient of a layer to be analyzed is calculated. With thus obtained diffusion coefficient as an index, quartz material in which metal diffuses with difficulty is sorted out. With thus sorted quartz material, a quartz member used for semiconductor manufacturing equipment such as a quartz tube is manufactured.

Process and system for detection of contamination in an imaging system, including providing an imaging system having one or more element having a surface for reflecting or refracting first incident radiation; mounting with respect to at least one of the one or more element one or more detector capable of sensing third radiation emitted or transmitted by one or more contaminant on the surface of the one or more element when second radiation is absorbed by the one or more contaminant; applying the first incident radiation and/or the second radiation to the at least one element; and detecting with the one or more detector the third radiation emitted or transmitted by the one or more contaminant.

A method and system for controlling a silicon nitride etching bath provides the etching bath including phosphoric acid heated to an elevated temperature. The concentration of silicon in the phosphoric acid is controlled to maintain a desired level associated with a desired silicon nitride/silicon oxide etch selectivity. Silicon concentration is measured while the silicon remains in soluble form and prior to silica precipitation. Responsive to the measuring, fresh heated phosphoric acid is added to the etching bath when necessary to maintain the desired concentration and silicon nitride:silicon oxide etch selectivity and prevent silica precipitation. The addition of fresh heated phosphoric acid enables the etching bath to remain at a steady state temperature. Atomic absorption spectroscopy may be used to monitor the silicon concentration which may be obtained by diluting a sample of phosphoric acid with cold deionized water and measuring before silica precipitation occurs.

A cavity enhanced absorption spectrometer (CEAS) and method for controlling the same. The CEAS includes a coherent electro-magnetic radiation source, an electro-magnetic modulator that creates a sideband with an adjustable frequency that is offset from the radiation source frequency by imparting an adjustable frequency modulation to the radiation. The CEAS also includes a RF source that drives the electro-magnetic modulator and a cavity enhanced absorption resonator (CEAR) that receives the sideband. A detector measures the proximity of the frequency of the sideband relative to the resonant frequency of the CEAR and generates a proximity detector signal, which is converted by a controller to a control signal that controls at least one of the RF source and the resonant frequency of the CEAR such that the frequency of the sideband and the resonant frequency of the CEAR are adjusted to maintain a predetermined proximity therebetween.

A method and system for measuring heat energy of a combustible fluid in which light having wavelengths in the near-infrared is directed into a test cell containing the combustible fluid and portions of the light not absorbed by the combustible fluid and passing out of the cell are spatially dispersed by wavelength, forming a light spectrum that is projected onto a detector. The light spectrum is digitized and inputted into a data processing unit in which it is compared to the actual spectrum of the light source stored in the system to determine the absorbance spectrum of the combustible fluid. The system is spectrally calibrated by identifying known spectral features of the combustible gas absorbance spectrum. To correct for deviations in the original light source spectrum, a light source calibration system is employed. Upon determination of the absorbance spectrum of the combustible fluid, the heating value of the combustible fluid is determined by comparing the absorbance spectrum to a plurality of spectra located within an on-board database.

Embodiments of optofluidic devices or methods according to the application can provide on-chip, label-free, massively parallel analysis of analytes. An embodiment of the optofluidic device can comprise a microresonator, a waveguide optically coupled to the microresonator, and a fluidic channel that exposes an analyte to an evanescent field from the microresonator, wherein the light signal has a linewidth lesser than the width of at least one resonance of the light signal propagating in the microresonator. The light signal can be tuned across a spectrum of light wavelengths, wherein the spectrum of wavelengths includes one or more wavelengths defining the at least one resonance in the microresonator. The light transmission through the waveguide over the spectrum of wavelengths of the input light can be detected, and an absorption spectrum of the analyte can be determined.

An optical absorption calorimeter performs absorbance measurements at low cryogenic temperatures, such as above 0K to 5K (e.g. near liquid helium temperature), using high-resolution thermometry with SQUID readout to probe optical absorption to better than 1 ppb. This improved sensitivity yields improved performance in calorimetric absorption spectroscopy by lowering the required excitation power, improving the spectral resolution, and opening up the full spectrum, from near-IR to near-UV and beyond for analysis.

A method for performing x-ray absorption spectroscopy and an x-ray absorption spectrometer system to be used with a compact laboratory x-ray source to measure x-ray absorption of the element of interest in an object with both high spatial and high spectral resolution. The spectrometer system comprises a compact high brightness laboratory x-ray source, an optical train to focus the x-rays through an object to be examined, and a spectrometer comprising a single crystal analyzer (and, in some embodiments, also a mosaic crystal) to disperse the transmitted beam onto a spatially resolving x-ray detector. The high brightness/high flux x-ray source may have a take-off angle between 0 and 105 mrad. and be coupled to an optical train that collects and focuses the high flux x-rays to spots less than 500 micrometers, leading to high flux density. The coatings of the optical train may also act as a “low-pass” filter, allowing a predetermined bandwidth of x-rays to be observed at one time while excluding the higher harmonics.

The present invention relates to methods and devices for in-situ measurement of reaction components of interest during manufacturing of polycarbonate by melt polymerization. The present invention describes irradiating a molten polymer sample with UV/visible light, and generating an absorbance profile correlated to Fries products as well as uncapped phenolic groups in the sample. The methods and apparatus of the invention are suitable for monitoring of Fries products in reactions ranging in size from small scale combinatorial formats to production scale reactors. Also included in methods of the invention are univariate and multivariate analysis for prediction of linear Fries, branched Fries and uncapped phenolic end-groups in unknowns.

The invention discloses a method for preparing manganese sulfate monohydrate by taking electrolytic manganese and industrial sulphuric acid as raw material; the method comprises the following steps: (1) the electrolytic manganese is ground and sieved to obtain manganese powder; the manganese powder is added in the industrial sulphuric acid and is heated to 80-90 DEG C and reacts for 4-12h continuously under the stirring condition, so as to obtain manganese sulphate suspension; the heavy metallic salt content in the manganese sulphate suspension is measured by atomic absorption spectroscopy; (2) the pH of the suspension is adjusted to 3-4, barium sulphide is added and filtration is carried out, so as to obtain filtrate 1; (3) lime stone is added in the filtrate 1, after the pH value is adjusted to be 5-6 and is placed still, so as to obtain the filtrate 2; (4) sodium fluoride is added in the filtrate 2 for reacting 20-26 hours and then is filtered, so as to obtain manganese sulphate solution; (5) after the manganese sulphate solution is concentrated and recrystallized, centrifugal separation, washing, drying and crashing are carried out, thereby obtaining the manganese sulfate monohydrate; the method has simple production process, easy operation, no pollution and low equipment requirements.

A system and method to discriminate between a first preselected gas and at least one other preselected gas use of an absorption spectroscopy analyzer that includes a Herriott cell and a temperature sensitive light source. The light source operates at a temperature that emits a beam at a wavelength that corresponds to high absorption by a first preselected gas. When a predetermined level of this gas is detected in a gas sample, the analyzer changes the operating temperature of the light source to emit a beam at a wavelength that corresponds to high absorption by a second preselected gas. The second preselected gas can be a different isotope of the first preselected gas.

The invention discloses a method and a device for measuring sulfur content in coal by ultraviolet absorption spectroscopy. In the measurement method, the decomposition scale and a threshold are determined adaptively by combining empirical mode decomposition with 3sigma criterion, and non-stationary characteristics of differential absorption degree per se can be fully retained, so the spectral interference problem caused by dust, water vapor and background gas in combustion gas is effectively solved; the instantaneous concentration of SO2 is obtained through calculation according to the differential absorption degree after noise reduction and trend term removal, and the total sulfur content accumulated in the coal sample combustion gas is calculated through the gas flow; the sulfur content in the coal can be obtained by dividing the coal sample amount by the total sulfur content separated from the coal sample combustion; and the pretreatment process needed to be performed on the combustion gas by coulometric titration and an infrared absorption method is avoided. The device for measuring the sulfur content in the coal by the ultraviolet absorption spectroscopy comprises a combustion furnace, a measuring chamber, an ultraviolet light source, a spectrometer, an air purifying device, a flow meter, a waste gas treatment device, a computer, and the like.