1,248,211. Wave-energy distance measuring; automatic phase control. THOMSON-CSF. 25 Oct., 1968 [31 Oct., 1967], No. 50842/68. Headings H3A and H4D. In relative phase determining apparatus, a signal of unknown phase is compared in a phase comparator 6 with a signal from a mixer 5 and the comparator output controls the frequency of a variable frequency oscillator 2, the inputs to mixer 5 being the output of a mixer 3-fed with the outputs of oscillator 2 and a fixed frequency oscillator 1-and an output from oscillator 2 as delayed by line 4. The invention is applied to measuring the distance d of a target 10, the transmitted waves being radio, acoustic or light. The measuring wave may be amplitude modulated on to a higher-frequency wave, e.g. a semi-conductor visible or invisible light source, Fig. 2 (not shown). The arrangement may be extended for higher precision over greater distances, utilizing two fixed, and two variable, frequency oscillators, Fig. 3 (not shown).

1,151,501. Determining the molar concentration of solutions, electrically. PERKINELMER Ltd. July 6, 1966 [April 6, 1965], No.14609/65. Heading G1N. The molar concentration or molecular weight of a solution is monitored by observing the change in resistance of a semi-conductor bead thermistor 39 as the solution flows from an outlet 37 of a tube 27 over the bead surface in the form of a film, which solution may be effluent from a chromatograph column (not shown). The bead resistance may be compared in a bridge with a fixed reference resistance, or alternatively with the resistance of a reference bead 41 over which a carrier liquid or solvent, as used in the column, flows in the form of a film from an outlet 38 of a tube 28. The vertical separation of the respective outlets and beads is adjustable to produce the films. The thermistor sensors are contained in an isopiestic chamber 19 (i.e. a chamber containing a constant vapour pressure of solvent) on the base of which is a pool 50 of solvent similar to that used as the carrier in the column. Over-flow funnels 40, 44 prevent contamination of the pool by the effluent. The inner surface 17 of the chamber is lined with absorbent material to assist evaporation of the solvent. Operation The chamber is within a thermally insulating casing 1, 2 which is temperature controlled and in operation is heated by an electric heater 7, air being circulated by a fan 10, until steady state temperature conditions are reached and the pressure of evaporated solvent remains constant which in general is when the chamber is saturated with solvent. The resistance of the beads will then be stable. The flow of the effluent solution and solvent over the thermistors is then commenced. Since the effluent comprises the solvent and traces of a sample under analysis it will have a lower vapour pressure than the solvent, dependent on the quantity and molecular weight of the sample constituents; which results in condensation of solvent vapour on the effluent surface whose temperature then increases. This increase is detected by the bead 39 and upsets the balance of a constant voltage input D.C. bridge. Equilibrium is reached when the vapour pressures of the effluent and solvent become equal, and the temperature difference which then exists indicates the molar concentration of the sample constituents on the bead 39 at that time. By adjusting the bridge until balanced a record of temp. difference is obtained or alternatively the bridge output may be connected to a chart recorder. The refractive index of the effluent may also be detected, and is dependent on density, also the molecular weights at various peaks can be derived by correlation of the reading of total mass and total number of moles. The arrangement may be used to compare two liquids.

1,174,005. Optical apparatus. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. Feb.3, 1967 [Feb.4, 1966], No.5335/67. Heading G2J. An element for use in A.T.R. spectroscopy is coated with a thin film 2, Fig. 2, of low refractive index and a second film 3 of high refractive index so that a beam 10 coming through the element is partially reflected at interface R 1 , 3 as beam 22 and partially transmitted as beam 18. On reaching the interface R 3,4 . the beam 18 interacts with the sample 4 and returns as beam 20 for further splitting up at interface R 1,3 . into beams 221, 181, so that the initial beam has a portion forming multiple reflections in the layer 3 and thus enhancing the absorption which is characteristic of sample 4. By arranging the reflectivity of interface R 1,3 to match that at interface R 3,4 and controlling the phase of components 221 so that they are 180 degrees out of phase with component 22, by suitably dimensioning the films 2, 3, and using polarized light, substantially complete absorption can be achieved at a wavelength characteristic of sample 4.

A method and apparatus for mass spectrometry, wherein the emergence or elution of an ion of interest, or a product ion of interest indicative of a transition of interest (such as a fragmentation reaction), is monitored. When it is determined that the ion or transition of interest has eluted, monitoring is discontinued for that ion or transition, or the dwell time for that ion or transition is reduced. In experiments where multiple ions of interest are monitored during a single acquisition, and, for example, a mass filter is used to scan the masses or mass to charge ratios (m/z) of ions of interest during a cycle, when elution of a first ion of interest is complete, for example from a liquid chromatographic source (LC), the filter may be controlled to discontinue monitoring for that mass or m/z and thereby improve the duty cycle of the other mass or m/z ranges.

A method and apparatus for mass spectrometry, wherein the emergence or elution of an ion of interest, or a product ion of interest indicative of a transition of interest (such as a fragmentation reaction), is monitored. When it is determined that the ion or transition of interest has eluted, monitoring is discontinued for that ion or transition, or the dwell time for that ion or transition is reduced. In experiments where multiple ions of interest are monitored during a single acquisition, and, for example, a mass filter is used to scan the masses or mass to charge ratios (m/z) of ions of interest during a cycle, when elution of a first ion of interest is complete, for example from a liquid chromatographic source (LC), the filter may be controlled to discontinue monitoring for that mass or m/z and thereby improve the duty cycle of the other mass or m/z ranges.

780,089. Photo-electric gauging apparatus. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Sept. 15, 1955 [Jan. 26, 1955], No. 2305/55. Class 40 (3). [Also in Group XXXVI] An instrument for gauging a dimension comprises separable members between which the specimen is received and a semi-conductor rectifying photo-junction across which a voltage is applied and which has a light pattern directed close to the junction, the arrangement being that the distance of the pattern from the junction varies with that of the dimension to be gauged so as to indicate the dimension on an electric current meter. As shown, the object to. be gauged is inserted between an anvil 3 and a ball-ended probe 4. Probe 4 is carried by flat springs 6, 7 and carries a block 11 of insulating material in which are mounted a pair of semi-conductor rectifying photo-junction of germanium P-N type. Fig. 2 shows the two junctions. An adjustable tube 19 carried on telescopic legs 17, 18 and containing lenses, a rotatable diaphragm and a light source directs a line of light 6 on the semiconductors so as to fall to one side of one interface in one case and the other side in the other. The connections are shown in Fig. 3, the semiconductors being arranged to form with potentiometer 30 a bridge circuit across which D.C. is applied from source 29. A current meter 31 is connected across the common cell connection and the potentiometer slider and is shunted at 33, 34 for adjustment. Fig. 4 shows an arrangement in which a pair of semi-conductors of P-N-P type have a wafer W of N type material on which are spots 151, 161 of indium. In a further construction the small spots are on the same side.