Abstract: In order to provide means for suppressing vibration of a balance arm of a thermogravity apparatus when changing a sample at low cost and with a minimal footprint, there is therefore provided a balance arm having a sample holder, a detector for detecting an amount of shift of the balance arm from an equilibrium position, a control circuit for carrying out feedback control towards the equilibrium position of the balance arm, a driver for driving the balance arm towards the equilibrium position, an exchange stage detector for detecting when a sample is being changed, and a fixed output holding circuit for maintaining the output of the driver at a fixed level while the exchange stage is indicated by the exchange stage detector, wherein output of the driver is fixed during the sample exchange stage.

Abstract: In order to provide means for suppressing vibration of a balance arm of a thermogravity apparatus when changing a sample at low cost and with a minimal footprint, there is therefore provided a balance arm having a sample holder, a detector for detecting an amount of shift of the balance arm from an equilibrium position, a control circuit for carrying out feedback control towards the equilibrium position of the balance arm, a driver for driving the balance arm towards the equilibrium position, an exchange stage detector for detecting when a sample is being changed, and a fixed output holding circuit for maintaining the output of the driver at a fixed level while the exchange stage is indicated by the exchange stage detector, wherein output of the driver is fixed during the sample exchange stage.

Abstract: A viscoelasticity measurement instrument having a support whose position can be varied relative to a sample holder for holding an end portion of a sample. A detection rod is resiliently held to the support, and holds a part of the sample. When a DC or AC force is applied to the detection rod, the displacement of the detection rod relative to the support is detected. The position of the support is varied or the DC force is varied to restore the displacement to zero. In this manner, the effect of the elastic constant of the support is eliminated. In one embodiment, a detection rod is support by leaf springs. Negative feedback control is utilized to return deformation of the leaf springs to zero at all times to eliminate the spring constant effect of the leaf springs. Since the average displacement of the leaf springs is zero, the positional relation between the permanent magnet and the coil forming the electromagnetic force generator varies negligibly.

Abstract: To eliminate pulsating current of vaporized gas by controlling a heater by means of a phase control, instead of controlling the heater by means of an on-off control which causes the vaporized gas to become a pulsating current, in a vaporized gas cooling apparatus using heater heating used in a thermal analysis apparatus and the like. By performing a phase control of the sine wave of the alternating power source by means of a thyristor and supplying power to the heater the duration of control at a time is reduced to as short as 10 msec (in case of 50 Hz). Accordingly, a filter effect is obtained by the fact that a changing speed of the heater temperature and a vaporization speed of coolant are too slow to follow the control action which prevents vaporized gas to become pulsating current. Since vaporized gas coming out is not a pulsating current, using this for cooling makes less fluctuation of temperature and makes the temperature more stable.

Abstract: In order to measure a complex dielectric constant, a sample 8 enveloped by a ring 9 and two laminas 10 is inserted between parallel plate electrodes constituted by an exciting electrode 2 and a response electrode 3. Measuring data is obtained as a measuring value of the sample 8 itself because an operational circuit 21 removes parasitic effects of the ring 9 and the lamina 10. Dielectric characteristics of a fluid sample can be obtained readily and accurately without contaminating the electrodes.

Abstract: Important portions for measurements such as measurement of a peak value can be measured with a substantially constant accuracy, by making an applied sinusoidal wave variable. An amplitude adjuster is disposed behind a sinusoidal wave generator. A sinusoidal wave applied to a voltage electrode is variable. An electrical current induced in a current electrode according to the nature of a sample is fed to an arithmetic portion via a current detector, a peak value-measuring device, and an A/D converter. The arithmetic portion performs a calculation. Then, an amplitude applied to the voltage electrode is determined and adjusted by the amplitude adjuster.

Abstract: A system for controlling the heater of a liquid nitrogen vaporization type cooling system includes a heater power computer circuit, a comparator, a synchronizing pulse generating circuit, an integrating circuit and a relay for automating the heater control to adjust the vaporization rate of the liquid nitrogen automatically.

Abstract: Apparatus for controlling the temperature of a sample in a thermal analysis system according to a temperature-control program in order to facilitate the production of rising and falling temperatures. The apparatus includes a first heater, a thermally insulating container having an opening and containing a mass of liquified coolant, a coolant vapor flow pipe, a sample chamber for containing the sample, a second heater, a sample chamber temperature detector, a temperature-control program setting circuit, a first power supply regulator and a second power supply regulator.

Abstract: An apparatus for providing an indication of the amplitude of a length signal having a top peak, a bottom peak and an intrinsic offset and being indicative of viscoelasticity of a sample. A peak measurement circuit is provided for measuring values of top and bottom peaks of the length signal to determine the amplitude thereof and an offset circuit is connected for providing a compensative offset. An adder circuit is provided for adding the compensative offset to the length signal. An offset calculation circuit receptive of the values of the top and bottom peaks from the peak measurement circuit is provided for outputting to the offset circuit, according to the received values, a control signal effective to control the offset circuit to provide an update compensative offset effective to cancel the intrinsic offset of the length signal.

Abstract: In order to provide a high-resolution A/D converter, the present invention is based upon the combination of two D/A converters, an input switch, an adder, an amplifier and a processor, wherein characteristics of the two D/A converters are learned relying upon the work of the processor and the switch, and the final digital output is corrected relying upon the thus learned characteristics to accomplish a high resolution.