Abstract: Sol-gel beds and deposits are utilized for SERS analysis of liquid analytes. Measurements are made at multiple points along the length of a column or channel to increase, very significantly, the speed of analysis, and use of the same medium to both separate the chemicals and also for SERS greatly reduces the complexity of such apparatus and enhances the efficiency of the method.

Abstract: A method for obtaining quantitative surface-enhanced Raman (SER) spectra that corrects for deficiencies of, and variations in, the materials and devices employed, especially the SER-active media utilized, employs a reference chemical, having an effective surface-enhanced Raman factor, of known concentration within the same SER experimental field of view as the analyte chemical being measured. Knowledge of the relative amounts of SER-scattering for the reference chemical and analyte chemical allows calculating the concentration of the latter to a high degree of accuracy and precision.

Abstract: Apparatus for use in effecting surface-enhanced Raman spectroscopy comprises first and second containment means, the first containment means containing a known quantity of a reference chemical having an effective surface-enhanced Raman factor, and the second containment means containing a surface-enhanced Raman-active medium and being sufficiently transparent, at least at one optical access location, to permit both the excitation irradiation of, and also the collection of surface-enhanced Raman scattered radiation from, a common field of view of the surface-enhanced Raman-active medium. The apparatus is constructed for carrying out the method of the invention; i.e., for effecting intimate mixing, substantially prior to introduction to the surface-enhanced Raman-active medium contained in the second containment means, of the reference chemical with an analyte chemical-containing solution introduced through an entrance into the first containment means.

Abstract: Sol-gel beds and deposits are utilized for SERS analysis of liquid analytes. Measurements are made at multiple points along the length of a column or channel to increase, very significantly, the speed of analysis, and use of the same medium to both separate the chemicals and also for SERS greatly reduces the complexity of such apparatus and enhances the efficiency of the method.

Abstract: Sol-gel beds and deposits are utilized for SERS analysis of liquid analytes. The use of the same medium to both separate the chemicals and also for SERS greatly reduces the complexity of such apparatus and enhances the efficiency of the method.

Abstract: A stationary medium is employed both to separate chemicals from a sample solution and also for surface-enhanced Raman spectral analysis of the separated chemical, thereby greatly reducing the complexity of the apparatus and enhancing the efficiency of the chemical analysis method. Measurements are made at multiple points along the length of a column or channel containing the medium to increase, very significantly, the speed of analysis.

Abstract: A stationary medium is employed both to separate chemicals from a sample solution and also for surface-enhanced Raman spectral analysis of the separated chemical, thereby greatly reducing the complexity of the apparatus and enhancing the efficiency of the chemical analysis method.

Abstract: Sol-gel beds and deposits are utilized for SERS analysis of liquid analytes. The use of the same medium to both separate the chemicals and also for SERS greatly reduces the complexity of such apparatus and enhances the efficiency of the method.

Abstract: Sol-gel beds and deposits are utilized for SERS analysis of liquid analytes. Measurements are made at multiple points along the length of a column or channel to increase, very significantly, the speed of analysis, and use of the same medium to both separate the chemicals and also for SERS greatly reduces the complexity of such apparatus and enhances the efficiency of the method.

Abstract: Metal-doped sol-gel materials, suitable for use as sensors for surface-enhanced Raman spectroscopic analysis for trace chemical detection, are produced by effecting gelation and solvent removal of a doped sol-gel under mild temperature conditions. At least in certain instances reaction and drying will desirably be effected in an oxygen-starved environment. The metal of the sol-gel material functions, when irradiated, to produce a plasmon field for interaction with molecules of an analyte in contact therewith, increasing by orders of magnitude Raman photons that are generate by excitation radiation, and the method allows matching of the metal and metal particle size to a wavelength of light (or incident radiation, e.g., laser radiation) to generate surface plasmons. The porosity of the sol-gel material dramatically increases the surface area, and thereby the amount of metal exposed for analyte interaction.

Abstract: The method determines the thickness and the free carrier concentration of at least one layer of a structure. An exposed surface of the structure is irradiated using spectral radiation, and the measured reflectance spectrum is compared to a calculated spectrum. Using algorithms that include terms representative of complex refractive indices, layer thickness, dielectric constants, and free carrier concentrations, values are iteratively assigned to the thickness and free carrier concentration parameters so as to produce a best fit relationship between the compared spectra, and to thereby determine those parameters.

Abstract: A process control method for controlling a polyolefin polymerization process, such as a solution polyethylene process, which includes five steps. The first step is to flow a stream of a solvent into a polyolefin reactor, such as flowing a stream of heptane solvent into the reactor at essentially a constant rate. The second step is to add a principal monomer to the stream of solvent, such as by adding ethylene at a controllable rate to the stream of solvent. The third step is to add a co-monomer to the stream of solvent, such as by adding 1-octene at a controllable rate to the stream of solvent.

Abstract: An improvement upon spectroscopic cells of the type that have a single window sealed to each window opening of the cell body. The improvement is: (1) to position an additional window at each such opening, each such window being juxtaposed, spaced apart and biplanar with each original window so that there is a sealed space between each additional window and each original window; and (2) to position at least two passageways through the body of the cell, each such passageway in fluid communication with each of the above formed sealed spaces so that any leakage of a sample past the original seal is vented from the cell via one of the passageways to a detector to be detected.

Abstract: A method for the on-line determination of the residence time distribution of a polymer extruder by injecting a quantity of dye, such as Mobay Red 5B, into the feed throat of the extruder and then photometrically monitoring the polymer flowing from the extruder for the dye. The advance of the present invention is to direct a single beam of polychromatic light through the polymer flowing from the extruder, e.g., by using a quartz-halogen light source and an optical fiber, and then to split this single beam of light that has passed through the polymer into two beams, e.g., by the use of a bifurcated optical fiber, each of which resulting beams are then passed through a separate filter to a separate photodetector. The wavelength of maximum transmission of one of the filters is selected to be near the wavelength of maximum light absorption of the dye so that the signal from the photodetector associated with this filter is a function of the concentration of the dye in the polymer flowing from the extruder.

Abstract: A photometric probe or a photometric cell having separate windows and a metallic probe body or cell body. The window(s) are sealed to the probe or cell body by brazed or frit seals which are less likely to leak after extended use in high temperature and/or high pressure industrial applications than probes and cells having gasket sealed windows. The windows can be made of sapphire, cubic zirconia, diamond, ruby, glass or quartz and, in the case of the probe, can be in the shape of an Attenuated Total Reflectance prism. The probe or cell body can be Kovar alloy or stainless steel.