34 results about "Laser induced fluorescence spectroscopy" patented technology

A method based on time-resolved, laser-induced fluorescence spectroscopy for the characterization and fingerprinting of petroleum oils and other complex mixtures. The method depends on exciting the wavelength-resolved fluorescence spectra of samples using ultraviolet pulsed laser radiation, measuring them at specific time gates within the temporal response of the excitation laser pulse, and comparing them in terms of their shapes alone without taking into account their relative intensities. The method provides fingerprints of crude oils without resorting to any kind of approximation, for distinguishing between closely similar crude oils of the same grade, and is useful in remote and non-remote setups, along with applications in fingerprinting blended and non-blended crude oils using different ultraviolet excitation wavelengths. Applications include estimating °API gravity of crude oils and monitoring degradation of mineral oils.

The invention provides optical switching-based systems and methods for catheter-based optical diagnosis which are particularly well suited to determining the condition of blood vessels, including the state of the vessels with respect to atherosclerosis and its development. Various embodiments provide catheter-based spectroscopic systems that are configured to cycle between different optical interrogation techniques such as Raman spectroscopy, optical coherence tomography and time-resolved laser-induced fluorescence spectroscopy. One embodiment of the invention provides an intravascular catheter-based diagnostic system that cycles between fingerprint region (200-2,500 cm⁻¹) Raman spectroscopy and high-wavenumber region (2,500-4,000 cm⁻¹) Raman spectroscopy.

A method based on spectral subtractions of normalized time-resolved laser-induced fluorescence (TRLIF) spectra produces multiple fingerprints of petroleum oils simultaneously. The method utilizes the simultaneous excitation of the TRLIF spectra of six oil samples using synchronized optical shutters. Five of the samples are standard oil samples while the sixth is the targeted sample. Instead of one fingerprint for the targeted sample, the technique produces multiple fingerprints representing the spectral subtractions between the normalized TRLIF spectra of the target sample and those of each of the standard oil samples. The technique provides fingerprints of higher distinguishing ability than a prior method, allowing it to discriminate between closely similar petroleum oils even under weathered conditions. The technique requires no sample preparation and can be applied remotely. It can also identify the original grade of the petroleum oils from their weathered remains.

A method for detecting polymer-based drag reducer additives in gasoline. One embodiment of the invention is a method for detecting the concentration of polymer-based drag reducer additives in gasoline, the method including the following: (a) placing a gasoline sample in a receptacle having at least two adjacent clear sides and irradiating one of the two clear sides of the receptacle with a pulsed laser beam, the pulsed laser beam having a wavelength in the ultra violet region shorter than 300 nm; (b) detecting laser-induced fluorescence wavelength resolved spectrum at 90° angle relative to the incident laser beam and through a slit defined in a diffraction screen, the diffraction screen being placed at a pre-defined first distance from the receptacle; (c) adjusting the position of the receptacle and slightly de-focusing the collimating lenses so that the low resolution fluorescence wavelength-resolved spectrum of the gasoline sample appears with a first peak at about 380 nm and a second peak at about 430 nm; (d) recording the laser-induced fluorescence wavelength-resolved spectra of the gasoline sample within a defined time-gate starting at the end of the temporal span of the laser pulse; and (e) comparing the percentage intensity of the first peak relative to the second peak for the laser-induced fluorescence spectrum near 380 nm of the gasoline sample to that of a gasoline sample free of any polymer-based drag reducer additives. In another embodiment of the method, the location of the diffraction-screen is at the pre-defined distance of between 0.5 mm to 2 mm from the side of the receptacle. In another embodiment of the method, the time-gate in step (d) is of 3 ns width and starting immediately after the end of the laser pulse.

The present invention discloses a single optical fiber endoscopic system integrating optical coherent tomography (OCT) and laser induced fluorescence spectrum (LIF). It is characterized by that said invention adopts wavelength division multiplex technique of optical fiber and utilizes the working waveband difference of OCT and LIF two diagnosis modes and double-mode characteristics of doubly-claded optical fiber to implement integration of single optical fiber endoscopic system of OCT and LIF. At the same time of that the fiber core mode provides single-mode transmission channel for OCT diagnosis mode it also can be used as transmission channel of fluorescence exciting light, and the inner cladding mode can provide transmission channel for fluorescence signal. The doubly-cladded optical fiber coupler can make the fluorescence signal be separated out from inner cladding of doubly-cladded optical fibre, so that the fluorescence spectrum measurement can be implemented.

The invention provides a comprehensive testing method of the optical performance of a deep ultraviolet optical element. According to the comprehensive testing method, the absorption loss absolute value of the deep ultraviolet optical element is measured based on the laser heat measurement technology; the fluorescence spectrum of the deep ultraviolet optical element is measured based on the laser-induced fluorescence spectrum technology when the deep ultraviolet optical element is irradiated by a deep ultraviolet laser; the defect level, the contents of doping components and the content of impurities of a material of the deep ultraviolet optical element are measured based on the Raman spectra technology. Through measurement of the absorption loss feature, the fluorescence spectrum feature and the Raman spectral feature of the deep ultraviolet optical element at the deep ultraviolet laser wavelength, the comprehensive optical performance of the deep ultraviolet optical element is estimated. By measuring the real-time change of the absorption loss, the fluorescence spectrum and the Raman spectrum of the deep ultraviolet optical element in the process of deep ultraviolet laser irradiation, the stability of the performance of the deep ultraviolet optical element is monitored. By the adoption of the same device, the optical feature parameters of the deep ultraviolet optical element are measured and the change of the optical feature of the deep ultraviolet optical element in the process of deep ultraviolet laser irradiation is monitored in real time.

The invention provides an autofocusing laser induced fluorescence spectrum detecting device and an autofocusing laser induced fluorescence spectrum detecting method based on a liquid lens. The detecting device comprises a light source emitter, a collimating lens and a narrow-band filtering sheet which are sequentially placed. A light source emitted by the light source emitter sequentially passes through the collimating lens and the narrow-band filtering sheet to generate an incident light source; the data information output end of a CCD (charge coupled device) is connected with the CCD data information input end processed by an information processing unit, and the adjustment information output end processed by the information processing unit is connected with the adjustment information input end of the liquid lens. The repeatability of detection results is guaranteed, and the measurement precision and the control flexibility are improved.

The invention relates to a method for identifying vegetable oil with doped strong tea by using laser induced fluorescence spectroscopy. The method comprises the following steps that (1), a laser induced fluorescence spectrograph is adopted to obtain an original fluorescence spectrogram of an oil sample; (2), a moving average method is adopted to perform noise elimination on original fluorescence spectrum data; (3), a Kennard-Stone dividing method is adopted to divide the fluorescence spectrum data into a training set and a test set; (4) a DE-GWO algorithm is used for optimizing an optimal penalty coefficient c and kernel function parameter g of an MSVC training model; (5) the spectrum data on the test set is used as input of the model to identify different types of oil samples. The methodfor identifying the vegetable oil with the doped strong tea by using the laser induced fluorescence spectroscopy has the advantages that the DE-GWO is adopted in combination with MSVC to be used for classification and identification of the vegetable oil with the doped strong tea by using the laser induced fluorescence spectroscopy, the classification accuracy rate and practical application value are high, the generalization ability is high, and the method is very suitable for real-time accurate detection and promotion of adulterated vegetable oil.

The invention discloses an identification method for a laser-induced fluorescence spectral image of water inrush in a coal mine. The method comprises the following steps of (1) acquiring an original fluorescence spectral image of a water sample by use of a laser-induced fluorescence spectroscopy; (2) performing zooming, cropping and graying preprocessing on the original fluorescence spectral imageof the water sample; (3) performing characteristic extraction on the preprocessed gray image by use of a PCANet (Principal component analysis Network) to obtain PCANet image characteristics; (4) partitioning a water sample specimen consisting of the PCANet image characteristics into an independent training set and an independent test set by use of a SPXY (sample set partitioning based on joint x-y distance) method; and (5) establishing a water inrush source identification model on the training set, and performing test on a model identification result through the test set. According to the identification method for the laser-induced fluorescence spectral image of the water inrush in the coal mine, the identification model for the fluorescence spectral image of the water inrush source in the coal mine by use of the PCANet is simply constructed, is simple for parameter optimization, meanwhile has high identification rate and identification speed and is suitable for online and real-time monitoring of the water inrush source in the coal mine.

The invention discloses a laser-induced fluorescence spectrum detection device, relating to the technical field of spectrum detection and aiming at solving the technical problems of low collecting efficiency and high demand on the form of a fluorescent material sample in the prior art. The laser-induced fluorescence spectrum detection device comprises a light source, a fluorescent probe and a grating spectrometer, wherein the fluorescent probe comprises a collimating lens, a narrow-band pass filter, an exciting light reflector, a dichroism light filter, a side pass filter and two focusing lenses; each part forms an exciting light path and a signal detection light path; the exciting light path starts from the light source, then sequentially passes through the collimating lens, the narrow-band pass filter, the exciting light reflector and the dichroism light filter, and then passes through the first focusing lens; the signal detection light path starts from the first focusing lens, then sequentially passes through the dichroism light filter, the side pass filter and the second focusing lens, and then enters the grating spectrometer. The laser-induced fluorescence spectrum detection device is especially suitable for detecting the fluorescence spectrum of fluorescent materials such as a quantum dot, water quality and jewel.

The invention discloses a laboratory detection device and evaluation method for the catalytic coefficient of a material surface based on LIF detection. The detection device comprises a laser inductionsource, a laser incidence regulating optical path, a hollow water-cooled stainless steel cavity, a high-power fiber-coupled laser, an energy meter, a radio frequency power, a fluorescence imaging optical path, an acquisition device, a dual-colorimetric pyrometer and a synchronous trigger device. According to the invention, in radio frequency inductively coupled plasma, a laser-induced fluorescence spectral diagnosis method is used for non-contact high-precision synchronous in-situ measurement of oxygen atom concentrations, temperature and other information of the material surface, and the catalytic coefficient of oxygen atoms on the material surface is directly obtained through cooperative usage of the atomic molar fraction gradient theory, thereby realizing non-contact accurate in-situ characterization and evaluation of the catalytic coefficient of the material surface under the conditions of different environmental parameters.

The invention discloses a temperature measuring method based on a carbon monoxide femtosecond laser induced fluorescence spectrum technology. The temperature measuring method comprises the steps of: generating femtosecond laser with a first central wavelength by using a femtosecond laser device, wherein the femtosecond laser is tuned to a second central wavelength after passing through a frequencydoubling crystal, the femtosecond laser with the second central wavelength is focused in a combustion field to be detected generated by a combustor after passing through a focusing lens, and excitesCO molecules in the combustion field to be detected to undergo resonance transition, so that the CO is excited to a high energy level; and transitioning the CO at the high energy level to a low energylevel, releasing a CO fluorescence signal having two sets of vibration and rotation spectrum bands, performing beam splitting on the CO fluorescence signal by means of a spectrograph, collecting CO fluorescence spectral signals by means of an ICCD camera and transmitting the CO fluorescence spectral signals to a computer, and analyzing the fluorescence spectrum by using the computer so as to obtain temperature information of the combustion field. The temperature measuring method is an optical measuring method, has a simple measuring system, has little interference on a flow field to be measured, and can realize the real-time online measurement of temperature in closed and open combustion fields.

The invention discloses a laser-induced fluorescence spectrum identification method for castor oil doped in edible oil, and relates to the field of food safety detection. The laser-induced fluorescence spectrum identification method for castor oil doped in edible oil comprises the following steps: collecting original fluorescence spectrum data of the edible oil doped with castor oil of different proportions by utilizing a portable edible oil fluorescence spectrum analyzer; filtering the spectral curve by adopting a polynomial smoothing method to eliminate noise; carrying out characteristic wavelength screening on the spectrum of the oil sample by using an SPA algorithm; and randomly generating a training set and a test set from the screened spectral data according to a ratio of 4: 1; and constructing an LSSVC model by using the training set data, and optimizing a model regularization parameter c and a kernel function width coefficient s by using a CSA algorithm. The SPA is combined with the CSA-LSSVC to be used for identifying and detecting the castor oil doped in the laser-induced fluorescent edible oil, and the method has very high recognition accuracy and practical value and ishigh in generalization ability and is very suitable for real-time and accurate detection and popularization of edible oil adulteration.

The invention discloses a laser-induced fluorescence spectrum colposcope. The invention uses laser light as the light source for inducing fluorescence, controls the laser scanning component to scan the cervical tissue site point by point, detects the excited fluorescence spectrum synchronously, and analyzes the correlation between the point-by-point acquired spectrum and the characteristic spectrum of the lesion to calculate the point-by-point lesion index , and then generate a lesion index distribution map. The invention can assist medical personnel to complete the detection process by adding an illumination source, an image sensor and the like. The laser scanning component, the spectrum acquisition component, the illumination source, and the image sensor realize light beam combining through the optical path beam combining component, and communicate the light with the lesion site through the positioning intubation tube. The invention utilizes the characteristics of high brightness, monochromaticity, and good directionality of laser light to irradiate the lesion with small spot area, high brightness, and high detection sensitivity. At the same time, it can excite laser-induced fluorescence specific spectra, greatly improving detection sensitivity and accuracy. .

The invention relates to a laser-induced fluorescence spectrum detection and identification method for red wine quality. The method comprises the following steps: (1) acquiring an original fluorescence spectrogram of a red wine sample by adopting a laser-induced fluorescence spectrum; (2) denoising the original fluorescence spectrum data by adopting a nonlinear wavelet transform threshold method;(3) carrying out iPLS waveband screening on the acquired laser spectrum to obtain a screened spectrogram; (4) dividing the screened fluorescence spectrum data into a training set and a test set by adopting a random division method; (5) optimizing the optimal penalty coefficient c and the kernel function parameter g of an SVM training model by adopting a PSO algorithm; and (6) establishing a red wine identification model on the training set, and testing an identification result of the model through the test set. The PSO is combined with the SVM to be used for detecting and recognizing the laser-induced fluorescence red wine, and the method has high classification accuracy and practical application value, is high in generalization capacity and is very suitable for real-time detection and popularization of adulterated red wine.

The invention provides a test system and a test method for jointly identifying oil types through terahertz waves and lasers. The system comprises a terahertz single-station time domain spectroscopy device, a laser-induced fluorescence spectroscopy device, a sample holding device and a sample detection device; the terahertz single-station time domain spectroscopy device and the laser-induced fluorescence spectroscopy device share the same laser source. The terahertz single-station time domain spectroscopy device directly radiates the terahertz waves, subjected to beam expansion by a beam expander, to a to-be-tested sample, the laser-induced fluorescence spectroscopy device directly irradiates the to-be-tested sample to generate a terahertz time domain signal and a fluorescence spectrum of the to-be-tested sample, and the sample detection device is used for detecting the to-be-tested sample according to the terahertz time domain spectral signal and the fluorescence spectrum. The detection and identification system can be used for testing and identification of all oil products, and has the advantages of comprehensiveness of identification types, high accuracy, high identification speed and low test cost, thereby being an oil product detection and identification product with an application prospect.

The invention discloses an improved DBSCAN mine water inrush spectrum identification method based on MVO. The advanced multi-cosmos optimization (Multi-Verse Optimizer (MVO) algorithm is used to improve the unsupervised clustering algorithm DBSCAN, and the parameter Eps of DBSCAN algorithm is self-optimized. Finally, the optimized parameters are combined with DBSCAN algorithm to identify the laser-induced fluorescence spectrum of coal mine water inrush. In the process of parameter optimization of the improved algorithm, the value interval of the cosmic position of MVO algorithm is set according to the spatial distance of the water sample spectral data, and the manual input parameters are reduced to the maximum extent possible. The improved DBSCAN algorithm based on MVO not only saves tedious manual parameter optimization process, but also can output the value interval of the parameter Eps corresponding to the optimal recognition rate. In addition, the unsupervised learning algorithm isused to identify the spectrum of coal mine water inrush, which can minimize the false identification of unknown water source.

The invention discloses a kernel principal component analysis (KPCA) algorithm based method for classifying coal mine well water sources. The method is performed as follows. A laser induced fluorescence spectrum sensor is adopted to acquire the fluorescence spectrum of to-be-detected water. A laser induced fluorescence spectrometer acquires the fluorescence spectrum data of to-be-detected water under a coal mine through optical fiber transmission. The obtained fluorescence spectrum data of to-be-detected water are uploaded through a CAN bus. Considering the depth and the complex environment under the coal mine, the method converts the CAN bus read fluorescence spectrum data into RS 485 signals through a CAN/RS 485 bus converter. After long distance transmission, the RS485 signals are transmitted to a RS485/RJ45 bus converter on the ground where they are converted into RJ45 network port signals that PCs could pick up. In this method, long distance transmission is made possible and data are finally transmitted to PCs where they undergo a spectrum pretreatment of wavelet de-noising through MATLAB and are then sent to a KPCA algorithm model to classify water resources. The classifying results are displayed on supervisory control and data acquisition software. With the method, it is possible to rapidly and accurately classify the water sources of water under a coal mine.

The method of detecting bladder cancer by optical analysis of bodily fluids utilizes optical techniques to determine a concentration of porphyrin in a patient's bodily fluid sample. The patient is administered 5-aminolevulinic acid and, approximately eight hours later, a bodily fluid sample is collected from the patient, and this bodily fluid sample is optically analyzed to measure a concentration of porphyrin therein. Optical analysis is preferably performed by laser-induced fluorescence spectroscopy. If the measured concentration of porphyrin is approximately three times a pre-determined porphyrin concentration for a healthy person of the same age as the patient, then the patient is diagnosed with bladder cancer.

The invention relates to a rapid identification method for rosewood varieties, and solves the problems that it is difficult for common consumers to distinguish dalbergia rueldii and pterocarpus santalinus in the rosewood varieties, professionals need to depend on experience and a standard wood slice microscopic identification method for identification, and the distinguishing difficulty is high. According to the method, the laser Raman spectrum technology and the laser-induced fluorescence spectrum technology are combined to rapidly and nondestructively identify the pterocarpus santalinus and the dalbergia rueldii, three laser wavelengths are adopted to irradiate a rosewood sample and obtain corresponding spectrums, Raman and fluorescence spectrum separation is performed according to fluorescence and Raman spectrum characteristics to obtain Raman and fluorescence characteristic spectrums of the sample, corresponding characteristic quantities are constructed to enlarge the spectral difference between the pterocarpus santalinus and the dalbergia rueldii, and then a discrimination model is established by applying multiple linear regression. According to the invention, Raman and fluorescence spectra of a sample can be obtained by a single CCD spectrometer, dalbergia rueldii and pterocarpus santalinus can be distinguished through modeling analysis, and nondestructive detection and identification are realized.