Abstract:
Disclosed is a method for detecting a change in weight by means of an impedance-scanning quartz crystal microbalance that can be coupled to an evaluation device. The quartz crystal microbalance is designed to transmit the measurement points recorded at a predetermined data recording rate as raw data to the evaluation device. Said method comprises at least the following steps: the measurement points of the raw data are linearly adjusted to a fractional-rational function; and at least one resonant frequency is determined from the adjusted measurement points of the raw data, a change in the at least one resonant frequency corresponding to an effective change in weight.
Abstract:
A thermoset film formed on a silicon wafer (16) is heated with a heat source (8) disposed under the silicon wafer (16). During the heating, a sublimate from the thermoset film is allowed to flow together with an air stream ascending toward an upper part in an enclosure (2) covering the thermoset film. The air stream directly adheres to a crystal oscillator (4) due to a nozzle (5) inserted into a detection part (3) disposed in the course of the air stream. Thus, the amount of the sublimate is measured in a real-time manner with respect to the lapse of heating time.
Abstract:
Application: the invention can be utilized within an automated system of control of the technological process of single crystal growth. Essence of the Invention: two boards are placed under a hermetic casing; one of them rotates along with the weight sensor, as the other remains static. An optoelectronic couple (that contains an LED and a phototransistor that are placed coaxially) is placed on top fo the boards. Signal is transmitted to the comptuer via the aforementioned optoelectronic couple. Technical outcome: by utilizing the string weight, higher measuring precision and higher sensibility (that allows automated crystal growth from a seedcrystal) can be achieved.
Abstract:
A system for measuring particulate concentrations includes a mass sensing device (10). Mass sensing device (10) has a sensing chamber (16) with an intake port (12) and an output port (30). Sensing chamber (16) is divided into an upper portion (14) and a lower portion (18) by a filter membrane (20) which is a planar, peripherally supported filter for entrapping the particulates. The system further features harmonic excitation driver (24) for oscillating the filter perpendicular to its planar surface and a sensor (27) for measuring the frequency of oscillation.
Abstract:
A method and a device for measuring a load in a dynamic state in which variations such as shaking and vibration occur. With a spring system composing member fixed at one end and made free at the other end, a load is applied to the free end for measuring instantaneous displacement Yi and indirectly measuring a static load We from the equation (a), where Wi = instantaneous load; g = gravitational acceleration; DELTA g(A/L)i = acceleration of the free end obtained from differentiation of displacement Yi performed twice, and k = spring constant. When variations such as shaking and vibration occur in the base for fixing the spring system composing member, a static load We is measured by the use of the equation (b), where DELTA g(G/L)i = acceleration of variation occurring in the base.
Abstract:
In a displacement detector, especially a displacement to frequency transducer for measuring pressure, comprising an oscillator (30) with a resilient vibrating reed (15) and signal processing means, the oscillator (30) including inductance members (20, 20') remaining in magnetic coupling, the resilient vibrating reed (15) comprises at least a first and a second leg (5, 5') connected by a coupling member (12) made of a ferromagnetic material, the first leg (5) being free for a displacement ( DELTA x) according to a pressure or other force causing this displacement ( DELTA x), the second leg (5') being fixed, the oscillator (30) including a first inductance member (20) determining a spacing (3) for receiving the coupling member (12), a second inductance member (20') for following the changes of the magnetic coupling between the coupling member (12) and the first inductance member (20), wherein the first and second inductance members (20, 20') are connected to means, especially an operational amplifier (IC1) for generating signals, particularly square wave signals of frequency corresponding to the displacement ( DELTA x).
Abstract:
A transducer for measuring stresses, elongations and forces, has a wire made of electrically conductive material which is secured under tension at two points electrically insulated from each other. The central region of the wire is arranged in a uniform magnetic field and the two points of attachment are connected electrically to a converter (10) with negative impedance which, together with the wire (1), is connected in an oscillating circuit. The frequency of vibration of the oscillator depends on the quantity to be measured, for example the stress.