A method for measuring a physical property of a polymer sample includes measuring a portion of a Raman spectrum of the polymer sample, determining a value of a preselected spectral feature from the portion of the Raman spectrum, and comparing the determined value to reference values. The value of the preselected spectral feature depends functionally on the physical property. The reference values relate the preselected spectral feature to the physical property. A probe includes a housing; first, second, and third optical systems attached to the housing; and a first optical filter located along a first direction. The first optical system is to collimate an illumination beam along the first direction. The first optical filter is to produce substantially monochromatic light and is insertable into the probe without substantially affecting an alignment between the probe and the sample. The second optical system is to focus light from the first optical filter on the sample and to collimate scattered light from the sample along a second direction. The third optical system is to focus scattered light from the second direction onto an aperture.
The present invention provides a method of and a device for measuring the stress in a semiconductor material. An excitation light is irradiated on a semiconductor material formed with a silicon germanium layer and a strained silicon layer in a multilayer structure on a single crystal silicon substrate from the direction of the strained silicon layer. An internal stress of the semiconductor material is measured from peak position information of the Raman spectrum of scattered light from the irradiating point, wherein light having a wavelength capable of reaching the single crystal silicon substrate is used as the excitation light, a temperature of the semiconductor material is estimated from a shift amount of the peak position of the Raman spectrum of the scattered light from the substrate in accordance with the irradiation of the excitation light and the shift amounts of the peak positions of the Raman spectra in the strained silicon layer and in the silicon germanium layer are corrected by means of the estimated temperature, The internal stresses of the strained silicon layer and the silicon germanium layer are calculated from the corrected peak position information of the Raman spectra in the respective layers.
The invention relates to the use of ratios, products and non-linear functions of adsorption, emission or scattering of light as variables in standard regression and chemometric techniques to predict a characteristic or property of a solid or liquid. The use of one or more non-linear functions within a relationship between measured spectral properties and characteristic properties of solutions and solids provides an improved means to determine a property when the intensities represent or relate to components that are colinear or interelated due to restraints associated with composition, chemical processes, or molecular structure. The invention relates to the use of ratios of Raman peak intensities to predict the properties of a solution or a solid such as pulp that is processed with the solution. The intensity of the Raman shifted light is used to create Raman peak intensity ratios. These Raman intensities are related to the concentration of species dissolved in the liquid. The Raman spectra are baseline corrected and the scattering from a water reference is subtracted before extraction of intensities for Raman peak intensity ratios. The Raman scattering intensities provide a good measure of the concentration of small, oxygenated molecules. The potential of an oxidative reductive process is conveniently determined using Raman peak intensity ratios. Relevant small molecules and complex ions in the pulp and paper industry include SO.sub.4.sup.2-, SO.sub.3.sup.2-, H.sub.2 O.sub.2, ClO2, HClO.sub.3, silicates, acetic acid, HClO.sub.3, Chlorate ClO.sub.3.sup.- ; Chlorous Acid HClO.sub.2, Chlorite ClO.sub.2.sup.-, Hypochlorous Acid HClO. Hypochlorite ClO.sup.-, phosphate, nitrate, nitrites. The method may also be used to determine a property related to the relative size, degree of polymerization, branching or network formation, of complexing or polymerized species. The method may also be used to measure large molecules such as hemicellulose, extractives and pectic substances.
A light filtering assembly for filtering an input beam of light having a plurality of desired wavelength components and a plurality of unwanted wavelength components so as to provide an output beam having only the desired wavelength components. The filtering assembly comprises an input section, a filtering section, and an output section. The input section divides the input beam into a plurality of polarized beamlets that travel along a corresponding plurality of spatially separated beam paths. The polarized beamlets comprise a plurality of desired beamlets corresponding to the desired wavelength components of the input beam and a plurality of unwanted beamlets corresponding to the unwanted wavelength components of the input beam. The filtering section is disposed in the paths of the beamlets so that the desired beamlets are passed and the unwanted beamlets are blocked. The output section is disposed in the paths of the desired beamlets exiting the filtering section and combines the desired beamlets so as to form the output beam. The output section is substantially identical to the input section to provide bi-directional capabilities. Because the beamlets are linearly polarized, the input and output sections are able to realize a high throughput efficiency.
The present invention provides a method for monitoring a reaction mixture using Raman spectroscopy. In a preferred embodiment, the invention provides a method for monitoring bulk and thin film melt polycarbonate polymerization reactions. In this method, the relative and absolute concentrations of the starting materials diphenylcarbonate (DPC) and bisphenol-A (BPA) are determined. Monitoring and maintenance of optimum stoichiometry in such a reaction is critical to ensuring desired polycarbonate product quality.
Alignment of multiple beam paths in a microscope such as a Raman spectrographic microscope utilizes an alignment instrument that is mounted on the stage of the microscope and positioned by the operator until an aperture of the alignment instrument is at an intended focal point of the microscope. A light source within the alignment instrument is turned on to project light through the aperture which is passed on a return light beam path to the input aperture of a spectrograph where it is detected. Features are included in the return beam path to adjust the beam path until the light detected is maximized, thereby aligning the return beam path to the intended focal point. The light source in the alignment instrument is turned off and a light source in the microscope system, such as a laser, is activated to provide an illumination light beam on a beam path that extends through the objective lens of the microscope, which focuses the beam onto the alignment instrument. The illumination beam that passes through the aperture is detected by a detector within the alignment instrument. The illumination beam path is then adjusted until the detected light is maximized, thereby aligning the illumination beam path to the intended focal point.
