Abstract: The present disclosure describes a differential refractometer for gradient chromatography. In an exemplary embodiment, the differential refractometer includes a solvent delay volume, an eluent flow meter coupled to an eluent inlet of a sample cell, a solvent flow regulator coupled to an outlet of the solvent delay volume and coupled to a solvent inlet of a reference cell, an instrument controller configured to receive the eluent flow rate from the eluent flow meter, configured to receive the solvent flow rate from the solvent flow regulator, configured to receive a flow rate ratio from a flow rate ratio data source, wherein the flow rate ratio indicates a ratio of the eluent flow rate to the solvent flow rate, and an optical bench configured to measure a difference between a refractive index of the eluent present in the sample cell and a refractive index of the solvent present in the reference cell.

Abstract: A brake system for a vehicle including: a brake caliper; a brake fluid container connected to a brake pipe; a brake hose connecting the brake pipe to the brake caliper; a refractometer arranged in the proximity of the brake caliper and configured to measure a refraction of the brake fluid at the brake caliper; a temperature sensor arranged in the proximity of the refractometer and configured to measure a temperature of the brake fluid in the proximity of the brake caliper; and a control unit configured to determine a water content of the brake fluid based on the measured refraction and the measured temperature.

Abstract: A plurality of light-receiving elements that are arranged in two rows are provided on a light-receiving surface of a detector. A slit image formed on this detector. One group of a plurality of the light-receiving elements are arranged consecutively in a displacement direction of the slit image to form a row (one light-receiving elements row), and another group of a plurality of the light-receiving elements are also arranged consecutively in the displacement direction of the slit image to form a row (another light-receiving elements row). The one light-receiving elements row and the other light-receiving elements row are in contact with each other.

Abstract: To provide a lighting apparatus etc. that is capable of obtaining various light distribution patterns and is superior in light utilization efficiency. The lighting apparatus includes a light source, a light conversion part for converting the light emitted from the light source into nearly parallel beams, a light modulating part having a plurality of pixel regions arranged so that the nearly parallel beams can be incident and capable of switching between a light transmitting state and a light scattering state for each of the pixel regions, and a projection lens disposed on the light path of the nearly parallel beams and on the light emitting side of the light modulating part and where the projection lens projects an image formed by the light modulating part using the nearly parallel beams.

Abstract: An embodiment of a refractive index detector includes a sample cell, a reference cell, a measurement section, a liquid inlet port, liquid outlet sections, and a switching mechanism. The inlet port leads to a sample cell inlet. A first outlet port and a second outlet port are for discharging a liquid. The switching mechanism includes a reference liquid supply mode for forming a channel for connecting a reference cell outlet to one of the first outlet port and the second outlet port while connecting a sample cell outlet to a reference cell inlet, and an analysis mode for forming a channel for connecting the sample cell outlet to one of the first outlet port and the second outlet port while sealing the reference cell outlet.

Abstract: Embodiments of the invention provide a method of determining one or more characteristics of a target object, comprising recording one or more diffraction patterns at a detector, wherein each diffraction pattern is formed by a target object scattering incident radiation, determining a phase map for at least a region of the target object based on the one or more diffraction patterns, and determining a refractive property of the target object based on the phase map.

Abstract: Refractometers for simultaneously measuring refractive index of a sample over a range or wavelengths of light include dispersive and focusing optical systems. An optical beam including the rang of wavelengths is spectrally spread along a first axis and focused along a second axis so as to be incident to an interface between the sample and a prism at a range of angles of incidence including a critical angle for at least one wavelength. In some cases, the prism can have a triangle, parallelogram, trapezoid, or other shape. In some cases, the optical beam can be reflected off of multiple interfaces between the prism and the sample. An imaging detector is situated to receive the spectrally spread and focused light from the interface and form an image corresponding to angle of incidence as a function of wavelength. One or more critical angles are indentified and corresponding refractive indices are determined.

Abstract: A method of calculating, using a computer, a refractive index of at least a portion of a specimen by using electromagnetic wave measurement. The method includes measuring a first scattered waveform from a structure of the specimen, measuring a second scattered waveform from a structure, in which a material for calculating a refractive index is disposed on a surface of the specimen, and comparing intensities of peak positions at corresponding portions of the first scattered waveform and the second scattered waveform.

Abstract: A flow cell for differential refractive index detection. The flow cell includes a transparent body that extends from a first end to a second end along a longitudinal axis. The transparent body defines a sample prism chamber and reference prism chamber. The sample prism chamber is configured to allow fluid flow between the first and second ends of the transparent body along the longitudinal axis. The reference prism chamber is configured to receive a reference fluid. The sample and reference prism chambers each include a grating comprising a plurality of grooves extending along the longitudinal axis in the direction of fluid flow.

Abstract: A gravimeter is disclosed that comprises a base, a reference device coupled to the base and configured to move along a first axis, a falling device configured to free fall from a first position to a second position on a second axis that is parallel to the first axis, a measurement module coupled to the reference device and configured to provide a first signal of the displacement of the reference device relative to the base and provide a second signal of the displacement of the falling device relative to the reference device. A processing unit accepts the first and second signals and computes a displacement of the falling device in inertial space by processing the first and second signals and subtracting the processed first signal from the processed second signal.

Abstract: Described herein are devices and methods for making extremely accurate measurements in a medium by continuously measuring the index of refraction of the medium such as water or biological tissue. Also described herein is a device for constantly measuring the index of refraction, and using the index of refraction data to constantly calibrate the optical measurement device. In addition, a primary measurement device (a ladar) that is optimized for data collection in a volume backscattering medium such as water or biological tissue is described, along with data results from the lab.

Abstract: A portable liquid design system includes a portable information handling system (IHS) that employs a liquid design application capable of operating in different modes to design different liquids such as corn syrup, espresso, coffee, soda pop and others. The portable liquid design system may include a refractometer to measure the refractive index and temperature of a liquid under test. The liquid design application may apply the measured refractive index and temperature to a 3 dimensional representation of the correlation of refractive index, temperature and concentration (% total dissolved solids) to determine a particular concentration corresponding to the measured refractive index and temperature. A single 3 dimensional scale may apply to virtually all values of interest of refractive index, temperature and concentration for a particular liquid under test.

Abstract: A method is described for separating and processing liquid-borne particles within an aliquot thereof following injection into a field flow fractionator. Said fractionation method may be employed also to capture, for subsequent segregation, specific predefined classes of such particles. The unique fractionation method disclosed contains means to control the applied transverse flow at each designated location along the length of said channel. In one embodiment of the method a separate compartment lies below each distinct location and corresponding membrane supporting permeable frit segment of the fractionator, providing the individual means to control the localized flow through the membrane section thereabove. Employment of a corresponding concentric compartment implementation achieves the same type of compartmentalized cross flow when applied to a hollow fiber fractionation means.

Abstract: Described herein are devices and methods for making extremely accurate measurements in a medium by continuously measuring the index of refraction of the medium such as water or biological tissue. Also described herein is a device for constantly measuring the index of refraction, and using the index of refraction data to constantly calibrate the optical measurement device. In addition, a primary measurement device (a ladar) that is optimized for data collection in a volume backscattering medium such as water or biological tissue is described, along with data results from the lab.

Abstract: A measuring method includes measuring a sum of an optical path length of a test object and a first medium in a first container, introducing light into an area that includes the first medium but does not include the test object and measuring the optical path length of the first medium, measuring a sum of the optical path length of the test object and a second medium in a second container, the second medium having a refractive index different from that of the first medium, introducing the light into an area that includes the second medium but does not include the test object and of measuring the optical path length of the second medium, and calculating a refractive index of the test object based on the measured optical path lengths and an actual distance of an optical path for which each optical path length is measured.

Abstract: Systems and methods for identifying refractive-index fluctuations of a target are described in this application. One embodiment includes identifying one or more properties of emergent light, the emergent light to be emergent from a target, and determining refractive-index fluctuations of the target based on the one or more properties of the emergent light. The determining refractive-index fluctuations further comprises determining one or more of the variance of the refractive-index fluctuations and the spatial correlation length of the refractive-index fluctuations. The determining refractive-index fluctuations further comprises determining one or more of the variance of the refractive-index fluctuations and the spatial correlation length of the refractive-index fluctuations.

Abstract: An apparatus includes a first support structure configured to support an element that has an alignment marker provided with at least one height difference. The apparatus also includes an alignment sensor comprising a light source that is configured to provide a light beam that illuminates the alignment marker; and at least one detector configured to detect the at least one height difference of the alignment marker by analyzing the light beam reflected by the alignment marker. Such an apparatus may be used to align of the element with respect to the first support structure.

Abstract: Described herein are devices and methods for making extremely accurate measurements in a medium by continuously measuring the index of refraction of the medium such as water or biological tissue. Also described herein is a device for constantly measuring the index of refraction, and using the index of refraction data to constantly calibrate the optical measurement device. In addition, a primary measurement device (a ladar) that is optimized for data collection in a volume backscattering medium such as water or biological tissue is described, along with data results from the lab.

Abstract: The invention provides an apparatus for measuring the differential refractive index for liquid chromatography which greatly improves the sensitivity while having quick responsiveness to refractive index difference of sample liquid, as well as a differential refractive index detector and a measurement method for a differential refractive index using the same. The apparatus for measuring a differential refractive index having a flow cell deflecting a measurement beam in accordance with the refractive index difference between a reference liquid and a sample liquid for measuring the change of the deflection angle on the basis of the refractive index difference of the measurement beam transmitted between the reference liquid and the sample liquid, wherein the flow cell comprises three independent chambers including a first chamber, a second chamber adjacent to the first chamber and a third chamber adjacent to the second chamber.

Abstract: An assay technique for label-free, highly parallel, qualitative and quantitative detection of specific cell populations in a sample and for assessing cell functional status, cell-cell interactions and cellular responses to drugs, environmental toxins, bacteria, viruses and other factors that may affect cell function.

Abstract: Provided is a differential refractive index detector having a light receiving element, a zero glass, a zero glass driving unit and a storing portion, and is capable of performing purging operation thoroughly based on a unified standard. The light receiving element receives a measuring light passing through cells (S, R) to generate a slit image. The zero glass makes the slit image parallelly move on the light receiving element. The zero glass driving unit makes the zero glass rotate. The storing portion stores a rotating angle of the zero glass when the same solution fills up the two cells (S, R). When a purging operation for replacing a reference solution in the flow cell is performed, the stored rotating angle is taken as a standard value for being compared with a current rotating angle of the zero glass. If the two angles are the same, the purging operation is finished.

Abstract: The invention provides an apparatus for measuring the differential refractive index for liquid chromatography which greatly improves the sensitivity while having quick responsiveness to refractive index difference of sample liquid, as well as a differential refractive index detector and a measurement method for a differential refractive index using the same. The apparatus for measuring a differential refractive index having a flow cell deflecting a measurement beam in accordance with the refractive index difference between a reference liquid and a sample liquid for measuring the change of the deflection angle on the basis of the refractive index difference of the measurement beam transmitted between the reference liquid and the sample liquid, wherein the flow cell comprises three independent chambers including a first chamber, a second chamber adjacent to the first chamber and a third chamber adjacent to the second chamber.

Abstract: Adjustment of a differential refractometer includes the steps of (a) equally focusing a slit image on separate portions of a photodetector, (b) decreasing the quantity of light of measuring beam, (c) making parallel movement of the slit image on the photodetector by a predetermined displacement, and (d) increasing the quantity of light of the measuring beam.

Abstract: Provided is a differential refractive index detector having a light receiving element, a zero glass, a zero glass driving unit and a storing portion, and is capable of performing purging operation thoroughly based on a unified standard. The light receiving element receives a measuring light passing through cells (S, R) to generate a slit image. The zero glass makes the slit image parallelly move on the light receiving element. The zero glass driving unit makes the zero glass rotate. The storing portion stores a rotating angle of the zero glass when the same solution fills up the two cells (S, R). When a purging operation for replacing a reference solution in the flow cell is performed, the stored rotating angle is taken as a standard value for being compared with a current rotating angle of the zero glass. If the two angles are the same, the purging operation is finished.

Abstract: An improved cell for a walk-off refractometer is disclosed that permits measurement of the differential refractive index, DRI, between a sample fluid and a reference fluid. In addition, the new cell design permits the measurement of the refractive index, RI, of a fluid relative to the refractive index of the material comprising or surrounding the flow cell. Thus a single instrument may be used to measure separately the RI of a sample fluid and the DRI between a sample fluid and a reference fluid. The new flow cell contains two chambers, typical of a DRI instrument, but an asymmetric internal angle in either the sample or the reference chamber. By the provision of this unique structure, it is an objective of this invention to be able to measure the refractive index of a fluid relative to the refractive index of the material comprising the flow cell or relative to the medium surrounding the flow cell, either of which may be considered a measurement of the RI of the fluid.

Abstract: An improved differential refractometer incorporating a photodetector array is disclosed. Using a multi-element photo array provides the basis for measurement of differential refractive index values with a heretofore unattainable combination of sensitivity of measurement and concurrent range of measurement. Within the large dynamic range attainable, the detector structure provides equal sensitivity irrespective of deflection within the range. The transmitted light beam is tailored to provide a spatial variation of the light intensity at the array improving thereby the precision of measurement of its displacement. This in turn results in improved precision in the reported differential refractive index and in the calculation of the differential refractive index increment dn/dc. Integrating the detector array into the flow cell structure of the parent case results in a detector of exceptional sensitivity and range for sample quantities far smaller than required by conventional differential refractometers.

Abstract: A new fluid interface position sensor has been developed, which is capable of optically determining the location of an interface between an upper fluid and a lower fluid, the upper fluid having a larger refractive index than a lower fluid. The sensor functions by measurement, of fluorescence excited by an optical pump beam which is confined within a fluorescent waveguide where that waveguide is in optical contact with the lower fluid, but escapes from the fluorescent waveguide where that waveguide is in optical contact with the upper fluid.

Abstract: This document describes an optical sensor unit and a procedure for the specific detection and identification of biomolecules at high sensitivity in real fluids and tissue homogenates. High detection limits are reached by the combination of i) label-free integrated optical detection of molecular interactions, ii) the use of specific bioconstituents for sensitive detection and iii) planar optical transducer surfaces appropriately engineered for suppression of non-specific binding, internal referencing and calibration. Applications include the detection of prion proteins and identification of those biomolecules which non-covalently interact with surface immobilized prion proteins and are intrinsically involved in the cause of prion related disease.

Abstract: To provide a differential refractive index detector free from fears for occurrence of personal errors in the judgement of stable condition and capable of performing highly efficient analysis operation, and a liquid chromatograph equipped with the detector.

Abstract: A differential refractometry apparatus that maintains optimal optical alignment of components while accurately providing differential refractometry measurements at elevated temperatures. The differential refractometry apparatus has a first thermal zone, a thermal isolation zone and a second thermal zone. The first thermal zone is configured to be located in an oven and exposed to higher temperatures. The thermal isolation zone is located adjacent to the first thermal zone and acts as a barrier to the conduction of heat from the first thermal zone into the second thermal zone. The second thermal zone is at a relatively lower temperature than the first thermal zone and its temperature is regulated using a thermal electric cooler located at its base. A flow cell, a mirror which reflects the incoming light beam, and an imaging lens are located in the first thermal zone.

Abstract: The radiation generated by at least one radiation source is controlled so as to generate a constant radiation intensity, thereby to cause the object to be heated, and the radiation intensity from the object at a first wavelength is sensed until it is equal to the present radiation intensity generated by the at least one radiation source, whereby the temperature of the object has a predetermined value. From that time on, the development of the actual temperature of the object is controlled accurately according to a predetermined program merely by sensing the radiation intensity from the object at a second wavelength larger than the first wavelength, and using the measuring signal representative of the sensed radiation intensity to continuously control the radiation intensity generated by the at least one radiation source.

Abstract: The present invention relates to a system for generating the same instantaneous pressure between two tanks filled each with a given medium, the first tank including at least one inlet channel and at least one outlet channel for the given medium, the second tank including at least one outlet channel, and means for opening and for closing said channels. The system according to the invention further includes at least one linking capillary between each tank, intended notably for transmitting instantaneously a pressure variation from the first tank towards the second tank.

Abstract: The invention relates to the measurement of the difference between refractive indexes of two media, traversed by a light beam the beams produce an interference figure consisting of fringes having a displacement which is measured.According to the invention, the displacement of the fringes of the interference figure is detected with a photosensitive device and a phase modulation is performed on at least one of the beams and the modulation is controlled in order to obtain a movement of the fringes of the interference figure.

Abstract: A device for quickly and accurately comparing the refractive index of an optical immersion liquid with the refractive index of a reference glass that the liquid is to be used with. The device comprises a cavity to at least partially contain the immersion liquid by the reference glass. The containment may be total, as in a hollow core, or may be between two windows composed of the reference glass and assembled in a spaced, facing relationship, one window having an inner face with a plano portion and a portion with a continuous slope, and a cavity intermediate the windows to contain the liquid being compared. The cavity is then filled with the liquid to be compared, transmitting laser light through the windows and the liquid to form an optical interference pattern.

Abstract: In order to satisfy both of high-sensitivity and low-sensitivity applications with no replacement of a flow cell, a photodetector (30) is divided into four portions (44-1, 44-2, 44-3, 44-4) by a first straight line (40) which is perpendicular to a direction of movement of a slit image (6) and a second straight line (42) which is inclined with respect to the direction of movement of the slit image (6) to intersect with the first straight line (40). Assuming that S.sub.1, S.sub.2, S.sub.3 and S.sub.4 represent intensity levels of detection signals of the photodetector portions respectively, the signals are processed along the following equations in analysis and preparative modes respectively:Sa=c{(S.sub.2 +S.sub.3)--(S.sub.1 +S.sub.4)}/{(S.sub.2 +S.sub.3)+(S.sub.1 +S.sub.4)]}Sp=c{(S.sub.1 +S.sub.2)--(S.sub.3 +S.sub.4)}/{(S.sub.1 +S.sub.2)+(S.sub.3 +S.sub.4)]}.

Abstract: An improved laser refractometer (10) employing a interferometer optical component (12), an object mirror (14) and an etalon (16). The etalon (16) is moved in the path of a plurality of reference beams (22, 24) and a plurality of measurement beams (26, 28) such that the reference beams (22, 24) travel through a vacuum within the etalon while the measurement beams (26, 28) travel a like distance through the etalon (16) in ambient air. In varying the distance traveled by the laser beams (22, 24, 26, 28) within the etalon (16) any interference fringes detected by an interference fringe detection device (20) are attributable to differences in the optical paths of the measurement beams (26, 28) as compared to that of the reference beams (22, 24) which, in turn, is entirely attributable to the ambient index of refraction. In a first preferred embodiment of the improved refractometer (10) the angular distance between a pair of plates (30, 32) is varied by rotation of the etalon (16).

Abstract: The invention relates to a transmitted-light refractometer wherein a slit diaphragm is imaged on a diode array through a cuvette holding the sample. The cuvette itself is arranged in the telecentric beam path. The exit window of the cuvette has several regions in which the inner surfaces of the exit window are inclined differently to the inner surface of the entry window. In this way, several slit images are generated on the diode array and the relative spacings of these images are independent of a possible disadjustment of the condenser and the objective. An embodiment of the invention permits the simultaneous measurement of the refractive index and the absorption of the sample.

Abstract: This invention measures the change of a fluid's refractive index with changes in the concentration of a solute dissolved therein. A determination of this quantity is required for many types of chemical analyses especially for the determination of molecular weights. The fluid is restricted to a thin capillary channel (11) within a transparent material (10) such as glass. A fine light beam (18) is incident upon the capillary at an angle close to the critical angle. The axes of the light beam and capillary intersect at a point within the capillary defining thereby a plane within which the refraction occurs. A position sensing (27) device is placed to measure the displacement of the beam twice refracted during its passage through the capillary channel, said measure being used to generate a numerical value of the ratio dn/dc, where dc is the change of solute concentration resulting in a change dn of the solution's refractive index.

Abstract: A differential refractometer in which: light from a light source is condensed on a lens; the light thus condensed is guided to a cell which houses a sample of which refractive index is to be measured and a reference of which refractive index is used as a reference value, the sample and the reference being housed as separated from each other in the cell; the light having passed through the cell is guided to an image sensor; and the amount of light deflection due to the difference in refractive index between the sample and the reference is measured, thereby to obtain the refractive index of the sample.

Abstract: The index of refraction of a liquid is measured using an optical fiber refractometer having a light transmitting optical fiber by immersing a portion of the optical fiber in the liquid and launching light into one end of the optical fiber at a selected non-zero launch angle with respect to the fiber axis. Light transmitted through the optical fiber is detected at the other end of the optical fiber and a determination is made of the index of refraction of the liquid in accordance with the detected light and the selected non-zero launch angle. By varying the launching angles of the light the range of the refractometer is increased. The light transmitting optical fiber is provided with a region having at least one tapered portion for further increasing the range of the refractometer. The tapered portion of the optical fiber is disposed between a refractive end of the optical fiber and the light source for providing single-ended operation.

Abstract: A differential refractometer is described capable of measuring the refractive index charge, dn, of a transparent fluid corresponding to a change dc of the concentration of a solute in said fluid. The fluid is restricted to a fine capillary within a transparent material such as glass. Incident upon the capillary at an angle close to the critical angle is a fine light beam incident from said transparent material. The axes of the light beam and capillary intersect at a point within the capillary defining thereby a plane within which the refraction occurs. A position sensing device is placed to measure the displacement of the beam twice refracted during its passage through the capillary, said measure being used to generate a numerical value of the ratio dn/dc.

Abstract: A refractive index measurement cell for liquid samples and method for measuring refractive indices of liquids are described which comprise a transparent tubular member closed at one end defining a sample volume of semicylindrical shape with respect to an axis for containing a liquid and having a diametrically disposed wall element including a flat surface defining the sample volume and containing the axis; a reference line coincident with the axis on the flat surface; a light source for projecting a light beam through the wall element, reference line and sample volume, whereby the beam is refracted at the flat surface; and a detector, selectively positionable about the axis of the tubular member, for detecting the light beam transmitted through the sample volume and for measuring the angular position of the beam about the axis.

Abstract: A liquid refractometer comprising a light source unit, a probe unit and a detection unit. The light source unit generates a beam of polarized mixed light composed of two coherent light waves that have been linearly polarized in directions at right angles to each other. The probe unit contains a polarization separation portion, a sample holding portion, a reference portion and a beam mixing portion. The polarization separation portion separates the mixed light beam back into the two polarized waves and directs one of the beams through the sample portion and the other beam through the reference portion. The mixing portion re-mixes the two waves after having passed through the sample holding portion and the reference portion. The detection unit receives the re-mixed light and measures the refractive index differences between the liquid sample and the reference portion. Fiber optics optically connect the light source unit, the probe unit and the detector unit.

Abstract: A fused glass refractometer cell is disclosed in which a lens is formed by the front surface of the cell and a reflective surface is applied to the rear surface of the cell. Means are provided to limit the passage of light through the cell to the central portion of the cell.

Abstract: Apparatus of the type including a light source directing a light beam through a measurement zone to a detector, wherein movement of the beam in a measurement direction with respect to the detector gives an indication of the measurement made in the zone, the improvement wherein the position of the beam with respect to the measurement zone is modulated through a preselected amplitude in a modulation direction, the amplitude being independent of light beam movements at the light source or in the path of the beam between the source and the modulating means, whereby the measurement can be made substantially independent of the beam movements in the modulating direction.

Abstract: Apparatus for measuring deflection of a light beam by sensing the beam with means providing two optical measurements, and providing an electrical output dependent upon the difference between the two measurements, with the instantaneous magnitude of each measurement being dependent upon the instantaneous deflection of the beam and upon the instantaneous intensity of the beam, the apparatus including electrical circuitry for including in the output an offset term dependent upon a scale factor and upon the instantaneous magnitude of at least one of the measurements, thereby making the offset term dependent upon the instantaneous intensity of the light beam, and means for initially zeroing the apparatus by adjusting the scale factor so as to make the output equal to a predetermined base value, whereby changes in the measurements due to changes in light beam intensity are offset by corresponding changes in the offset term, so as to thereby reduce the influence of beam intensity on the output.

Abstract: A highly sensitive measuring cell for a differential refractometer of the interference type for chemical analyzers comprises two channels in a measuring body, one of said channels conveying a medium whose refractive index is to be measured and the other channel conveying a reference medium of known refractive index. The respective path lengths of the measuring channel and the reference channel are mechanically adjustable to exactly the same lengths in order that a maximum common mode rejection ratio (hereafter "CMRR") value may be achieved.

Abstract: Disclosed herein is a high-sensitivity differential refractometer which is characterized by having a light source disposed outside a housing, a reflecting mirror attached at the end portion thereof to a reflecting mirror-supporting plate connected with the end of a movable plate, said movable plate being so constructed as to rotate around a vertical axis and permit free change of the angle formed between said reflecting mirror-supporting plate and the movable plate, a twisting member disposed inside a lead-in tube and said lead-in tube fastened to a removable case and built in a metallic block inside the housing.

Abstract: To reduce errors in a measuring instrument caused by temperature effects from changes in the flow rate of fluids passing through the instrument, the flow of heat is adjusted to balance the flow-rate-dependent temperature increases against the flow-rate-dependent temperature decreases that occur with the same change in flow rate in each flow path. Some of the techniques for adjusting the flow of heat are: (1) controlling the temperature of the fluid at the inlet of the instrument with one heat exchanger and the temperature of the body of the instrument with another heat exchanger; (2) controlling the temperature of the walls of the instrument with a heating coil; and (3) emitting heat within the flow path from a transducer. A typical measuring instrument in which such errors are reduced is a refractometer used to measure characteristics of a fluid flowing through a column.

Abstract: A refractive index variability measuring system using a configuration of ical interferometers, mirrors, windows and receivers is desirable. The system provides an improved and a distinctive method for vibration and thermal expansion cancellation. Additionally, an improved matching of optical paths by using this system allows for growth of several measurement paths without additional mismatch of measurement and vibration canceling paths.