185 results about "Absorption cross section" patented technology

An apparatus and method for rapidly and accurately identifying and quantifying analytes in a complex mixture is disclosed. The apparatus comprises an ultra-sensitive cavity-enhanced spectrometer coupled to data-collection and analysis devices. The method comprises the use of a database containing the absorption cross-sections of various analytes to numerically determine the composition of the sample.

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.

A method for characterizing a coating comprising a pigment and metallic flakes, said method by directing beams of light toward a coating; measuring the reflectance of light from the coating at the specular angle; measuring the reflectance of light from the coating at one or moren on-specular angles; analyzing said measured light at the specular and non-specular angles as a function of wavelength; and determining the K/S of the pigment and the volume fraction of said metal flakes within the coating from the measurements of the specular and non-specular reflectance; wherein K is the absorption cross-section of the pigment multiplied by its volume concentration; and S is the scattering cross-section of the pigment multiplied by its volume concentration.

A method to increase the output power of narrow-linewidth rare earth-doped fiber amplifiers by suppressing simulated Brillouin scattering. The fiber amplifier is seeded with two or more lasers having frequencies and input powers that are sufficiently different. The seed signal with the highest emission cross section (e.g., signal 2) initially experiences the greatest gain. If signal 2 is also given sufficiently greater input power than signal 1, it will be amplified to its maximum value before the seed signals have reached the midpoint of the gain fiber. Beyond that point, the signal having the lower emission and absorption cross sections (signal 1) and significantly lower input power will continue to experience gain by power transfer from both signal 2 and the pump light, attaining a power output well beyond what the maximum output would have been had the amplifier been illuminated with a single frequency beam. This technique effectively reduces the Stokes light of signal 1, whereby higher power narrow-linewidth optical fiber amplifiers may be realized.

Composite materials that can be used to block radiation of a selected wavelength range or provide highly pure colors are disclosed. The materials include dispersions of particles that exhibit optical resonance behavior, resulting in the radiation absorption cross-sections that substantially exceed the particles' geometric cross-sections. The particles are preferably manufactured as uniform nanosize encapsulated spheres, and dispersed evenly within a carrier material. Either the inner core or the outer shell of the particles comprises a conducting material exhibiting plasmon (Froehlich) resonance in a desired spectral band. The large absorption cross-sections ensure that a relatively small volume of particles will render the composite material fully opaque (or nearly so) to incident radiation of the resonance wavelength, blocking harmful radiation or producing highly pure colors. The materials of the present invention can be used in manufacturing ink, paints, lotions, gels, films, textiles and other solids having desired color properties. The materials of the present invention can be used in systems consisting of reflecting substances such as paper or transparent support such as plastic or glass films. The particles can be further embedded in transparent plastic or glass beads to ensure a minimal distance between the particles.

A system and method of detecting entangled photon pairs, each pair including a signal photon and an idler photon, is disclosed. Entangled photon pairs are provided having an entanglement time and an entanglement area selected to substantially increase an associated entangled two-photon cross-section of an associated target medium. The entangled photon pairs are also selected to have an energy distribution between the signal photon and the idler photon to substantially decrease an associated random two-photon absorption cross section of the target medium. The entangled photon pairs are directed to the target medium, and at least one entangled-photon pair being absorbed by the target medium is detected. The techniques for detecting entangled photons may be adapted to accommodate hiding information in entangled photons. That is, these techniques may be used for quantum steganography.

The invention discloses an inversion method of micro-pulse differential absorption lidar water vapor spatial and temporal distribution. The inversion method comprises wavelength selection of water vapor detection, calculation and correction of absorption cross sections of water vapor absorption wavelengths and non-absorption wavelengths, and inversion and calibration of water vapor concentrations. An automatic continuous detection device of the micro-pulse differential absorption lidar water vapor spatial and temporal distribution is employed to obtain characteristic backward scattering signals of water vapor absorption in specific spectral lines, the backward scattering signals are subjected to inversion and calibration by a computer utilizing a differential absorption spectrum analysis method, and high-time-resolution, high-spatial-resolution and high-precision water vapor stereo distribution data is obtained.

The invention provides a method for optimizing laser radar detection atmospheric composition spectral line analysis, through building of an IPDA laser radar equation of hard target reflection, calculation of difference optical thickness of two pulses and CO2 air column mixing rate XCO2 with a weight, single spectral line broadening calculation, absorption cross section calculation, CO2 absorption optical thickness calculation, a weight function profile and a CO2 molecule number density profile, weight function-optimized spectral lines are obtained. The spectral lines obtained by the method have a higher lower-atmosphere weight ratio, and detection is closer to a true value.

A robust methodology is described herein for determining the algae biomass photoautotrophic yield (in gram of biomass synthesized per μmole of absorbed photons), which is useful for reliable biomass productivity estimates for selecting, comparing, and optimizing algae cultures for large-scale production. Another method is provided herein to increase dissolved inorganic carbon concentration and alleviate limitations common in aerated small-scale batches. This carbonate addition method allows for a more accurate determination of the algae culture photoautotrophic yield under small-scale experimental conditions. Also provided herein is a method for estimating a light spectrum-dependent scatter-corrected algae-specific absorption cross section, which permits the use of Beer's law to estimate the fraction of photons absorbed by a given algae culture. Determination of the algae photoautotrophic yield and absorption cross section enable a full photobioreactor parameterization and the resulting capacity to achieve highly controlled nutrients-supply conditions.

The present invention provides a method and an apparatus for calibrating a first self-powered neutron detector for long term use in a nuclear reactor core with a second self-powered neutron detector, where the emitter material of the second self-powered neutron detector has a neutron absorption cross-section that is greater than the neutron absorption cross-section of the first emitter material for the first self-powered neutron detector.

The invention provides a coherent differential absorption laser radar comprising a first tunable continuous wave laser, a second tunable continuous wave laser, a beam splitter, an acousto-optic modulator, a laser amplifier, a circulator, a transmitting and receiving telescope, a coupler, a balance detector, an acquisition card and a digital signal processing system. Two required laser wavelengthsare determined by selecting appropriate absorption lines of gas molecules to be tested in intermediate infrared, then local oscillation light and signal light are split by the beam splitter, frequencies are finally combined by the coupler, and the balance detector is used for detection to obtain a concentration of the gas molecules. Due to the larger gas absorption cross-section coefficient and lower background radiation of the intermediate infrared, the detection sensitivity is improved. The use of coherent detection instead of direct detection reduces the influence of low quantum efficiencyon the precision of detection, improves the utilization of echo signals, and improves the performance of the differential absorption laser radar.

Effective radiation shielding is required to protect crew and equipment in various fields including aerospace, defense, medicine and power generation. Light elements and in particular hydrogen are most effective at shielding against high-energy particles including galactic cosmic rays, solar energetic particles and fast neutrons. However, pure hydrogen is highly flammable, has a low neutron absorption cross-section, and cannot be made into structural components. Nanocomposites containing the light elements Boron, Nitrogen, Carbon and Hydrogen as well dispersed boron nano-particles, boron nitride nanotubes (BNNTs) and boron nitride nano-platelets, in a matrix, provide effective radiation shielding materials in various functional forms. Boron and nitrogen have large neutron absorption cross-sections and wide absorption spectra. The incorporation of boron and nitrogen containing nanomaterials into hydrogen containing matrices provides composites that can effectively shield against neutrons and a wide range of radiation species of all energies without fragmentation and the generation of harmful secondary particles.

The invention discloses an atmospheric NO3 free radical concentration measurement system based on a double-cavity type cavity ring-down technology. The measurement system utilizes two ring-down cavities to simultaneously measure the ring-down time and the background ring-down time, and includes a function generator, a diode laser device, an optical isolator, a first ring-down cavity, a second ring-down cavity, a narrowband color filter, a photoelectric detector and a capture card. The external-modulation diode laser device outputs a pulse laser, the pulse laser passes through the optical isolator and then is divided into two beams by a beam splitter, the two beams of pulse lasers respectively go into the first ring-down cavity and the second ring-down cavity, and the two ring-down cavities are in rear-connection with the photoelectric detector. The NO3 free radical ring-down time is extracted from an obtained ring-down signal acquired by the first ring-down cavity; and at the same time, the NO3 free radical background ring-down time is extracted from the ring-down time obtained by the second ring-down cavity. Under the condition of a known NO3 free radical absorption cross section sigma, the NO3 free radical concentration is obtained by calculation through the following formula as described in the specification, where RL and c are constants.

The invention relates to a method for obtaining an intermediate resonance factor in a reactor multigroup nuclear database. On the basis of a free gas model, a continuum energy neutron scattering matrix expression Sigma<r, s, T> (E->E') of the resonance absorption nuclide relevant to the temperature TK is obtained through formula derivation; a neutron slowing down equation is solved on the basis of the continuum energy neutron scattering matrix at the temperature TK to obtain the neutron-flux density at the temperature TK; the multigroup adsorption cross section of the resonance absorption nuclide at the temperature TK is further worked out through group merging calculation; the intermediate resonance factor is finally obtained through the intermediate resonance factor calculation; and an intermediate resonance factor multinomial coefficient using the temperature and the background cross section as independent variables is obtained by a least squares fitting method. The method provided by the invention has the advantages that the intermediate resonance factor after the intermediate resonance factor calculation is more accurate; the calculation precision and the calculation efficiency of the intermediate resonance factor are improved; and finally, in the reactor physical calculation, the resonance calculation precision is improved, and the resonance calculation speed is accelerated.

The invention discloses a detection apparatus and a detection method of photosynthesis of phytoplankton on the basis of chlorophyll fluorescence. The detection apparatus includes an excitation-emission optical structure, an excitation light source driving module, a main control module, and a fluorescent detection module and a light source reference photo-detection module, wherein the structure of the fluorescent detection module and the light source reference light detection module are same. According to the invention, an optical pulse-varying light source is employed with combination of a double-channel signal detection module, quick and accurate measurement of three optical-induced fluorescent dynamic process comprising single-turnover, multi-turnover and relaxation is achieved. By means of analysis on a fluorescent dynamic curve, a plurality detail parameters representing the photosynthesis situation, comprising functional absorption cross section, maximum photochemical quantum efficiency, electron transfer rate and the like of photosynthesis, can be obtained.

The invention designs a real-time compensation method of measurement errors caused by spectrograph wavelength drift. The method comprises the following steps: calculating the spectrograph wavelength drift by utilizing real-time measured spectral data of a measured gas and an absorption cross section database of the measured gas measured in a laboratory, and calculating the spectrograph wavelength drift; calculating a measured gas absorption cross section corresponding to a translational wavelength of the wavelength drift and measured gas absorbance for calculating concentration of the measured gas; eliminating the measurement errors caused by the wavelength drift in real time.

The present invention is multiramose double photon pumped fluorescent oxdiazole material and its preparation process. The oxdiazole material is prepared with polycyclic arene bromide and 3, 5-bis{2-(4-tertiary butyl phenyl)-5-[1, 3, 4]-oxdiazolyl}-styrene or 2-(4-tertiary butyl phenyl)-5-[1, 3, 4]-oxdiazolyl-styrene, and through Heck reaction inside mixed solvent of triethylamine and N, N-dimethyl formamide catalyst under the action of catalyst palladium acetate and tri-o-methylphenyl phosphide; or prepared with triphenylamido aromatic aldehyde derivative and benzyl bromo triphenyl phosphine containing [1, 3, 4]-oxdiazole structure, and through solid and liquid Wittig reaction. The oxdiazole material possesses sufficient double photon absorption cross section, high double photon fluorescence efficiency and high heat stability, and can emit strong double photon up converted green and blue fluorescence under the excitation of 800 nm laser beam.

The invention relates to a detection device and a detection method of ammonia gas and sulfur dioxide gas concentration. The device consists of an ultraviolet light source, a collimate lens, a runner, a gas absorption pool, a convergent lens, an ultraviolet optical fiber, a spectrograph and a computer. By adopting the detection device and the detection method, the problem that the FFT characteristic frequency peak values of the absorption spectrum of two gases interfere with each other can be solved. The detection device and the detection method have the advantages of not needing measurement on a gas absorption cross section and being simple in calculation, high in response speed and the like, the temperature and pressure do not need to correct the absorption cross section, the cost is low, and the stability is good.

An organic electroluminescence device having two electrodes and a plurality of organic layers between the two electrodes, in which the organic layers include a light emitting layer that emits light when an electric field is applied between the two electrodes. The device further includes a plurality of metal fine particles, which generates a local plasmon by light emitted from the light emitting layer, inside of at least either one of the electrodes or adjacent to a side of the electrode facing the organic layers and inside of a conductive organic layer, and at least some of the plurality of metal fine particles are disposed adjacent to the light emitting layer. Here, as the metal fine particles, particles having a scattering cross section σ_S which is larger than an absorption cross section σ_A thereof with respect to light emitted from the light emitting layer are used.

The invention discloses a triphenylamine-naphthalene multi-branch molecule with double-photon polymerization initiation characteristics. Triphenylamine is taken as an electron donor, and naphthalene nucleus with characteristics of an electron receptor are respectively connected with the 4, 4'-bits of triphenylamine through carbon-carbon double bonds to form the topology of'Y-pn knot' with charge transferability; and then the'Y-pn knot' is taken as a connection center to be conjugately connected with a substituent to form a multi-branch molecule with a greater conjugate system. Therefore, the molecule has a great double-photon absorption cross section. The multi-branch molecule has excellent double-photon polymerization initiation capability for methacrylic acid resin with a low polymerization threshold value and a highly fine microstructure obtained from polymerization. The multi-branch molecule has great application value in the double-photon three-dimensional memory and the micro-processing and fabrication fields of photon crystal.

The invention discloses a method for separating boron isotopes by simulated moving bed chromatography. The method is used to selectively separate isotopes 10B with high thermal-neutron-absorption cross section from boric acid by simulated moving bed chromatograph with a sassolite solution as a raw material, deionized water as a mobile phase, and weak-base anion-exchange resin as a stationary phase. The method comprises the following steps of: preparing a boric acid aqueous solution with certain concentration, filtering the boric acid aqueous solution for removing impurities to obtain a sampleinjection solution for a simulated moving bed, then loading samples by the simulated moving bed, collecting condensed boric acid rich in isotopes 10B at an extraction port, and then obtaining a target product by evaporation concentration. The method for separating the boron isotopes is continuous and has high separation efficiency.

The invention discloses a concentration quantification method of a broadband cavity strengthening type atmosphere NO2 detection system. The detection system is equivalent to a light optical path difference absorption spectrum (DOAS) detection system, the characteristic of the stable oxygen dipolymer content in atmosphere is utilized to obtain a light-absorbing optical path of the detection system, and the size of the concentration of the atmosphere NO2 is quantified. The quantification method comprises the following steps: determining an effective optical path function; selecting a measuring wave band, and calculating an effective optical path of an oxygen dipolymer absorption peak wavelength; calculating a correction factor of a gas absorption cross section, and correcting the absorption cross section of the gas; calculating the optical thickness to obtain the concentration of a gas pillar by virtue of DOAS matching; calculating the absorption optical path, and calculating the concentration of the atmosphere NO2. Compared with the existing method, the concentration quantification method provided by the invention has the advantages that the reflectivity of a lens is not needed to be calibrated, the operation process of the detection system is simplified, and the influence of a calibration error of the reflectivity of the lens on the quantification result is avoided.