Abstract: A method for differentiating between a liquid sample having clogs therein and a liquid sample having an abnormally elevated viscosity during a liquid aspiration process by relating the ratio between the maximum negative pressure during aspiration and an equilibrium pressure prior to dispensation to viscosity.

Abstract: Analyzing the pressure profile generated during a limited period of time immediately prior to the end of a liquid aspiration process and comparing the standard deviation of the residuals to a critical value to determine if the liquid was of a desired sufficient volume.

Abstract: A method for differentiating between a liquid sample having clogs therein and a liquid sample having an abnormally elevated viscosity during a liquid aspiration process by relating the ratio between the maximum negative pressure during aspiration and an equilibrium pressure prior to dispensation to viscosity.

Abstract: Analyzing the pressure profile generated during a limited period of time immediately prior to the end of a liquid aspiration process and comparing the standard deviation of the residuals to a critical value to determine if the liquid was of a desired sufficient volume.

Abstract: A liquid aspiration method which includes a method for determining the quality of the aspirated sample through mathematical analysis of the standard deviation of the residuals of the linear regression analysis of the aspiration pressure profile generated between the onset of actual aspiration and the end of actual aspiration and comparison of the results with predetermined known values.

Abstract: A liquid aspiration method which includes a method for determining the quality of the aspirated sample through mathematical analysis of the standard deviation of the residuals of the linear regression analysis of the aspiration pressure profile generated between the onset of actual aspiration and the end of actual aspiration and comparison of the results with predetermined known values.

Abstract: A data compression system includes a logarithmic ratioing network configured from only two chopper stabilized operational amplifiers connected to a dual slope analog-to-digital converter having a signal integrate time t.sub.int. The system is characterized in that the chopping frequency of the chopper stabilized operational amplifiers is equal to the inverse of an integer number N times the signal integrate time of the converter. For the analog-to-digital converter to average to zero the noise output due to chopping, the chopper stabilized operational amplifiers are driven together at the chopping frequency.

Abstract: A digital key system is disclosed which includes a programmable read only memory which is automatically programmed with the code for unlocking the system during initial removal of the key from the lock.

Abstract: A nematic liquid crystal display device exhibits dielectric anisotropy when the device is in a normal operating temperature range. By placing electrodes on either side of the layer of liquid crystal material and applying across the material an electric field insufficient to change the molecular orientation in the material, the capacitance and therefore the dielectric constant of the material is measured. A similar measurement of dielectric constant is made with a strong electric field applied across the material such that the molecules are re-oriented unless the device is so cold that the molecular change cannot occur and the device is inoperative as a display. By comparing the dielectric constants, it is determined whether the device is at a suitable operating temperature and a heater for the device is controlled accordingly.

Abstract: A twisted nematic liquid crystal device contains a liquid crystal material having dielectric anisotropy .DELTA..epsilon. which is positive for certain values of temperature and frequency of an electrical signal applied across the material and negative for other values of these parameters. The device includes a heater and a test area (separate from the display area of the device) at which transmittance of light is monitored by a heater control circuit. A test frequency chosen to give .DELTA..epsilon..apprxeq.0 at the minimum desired operation temperature of the device is applied across the test area and the light transmittance is monitored to assure that the temperature is high enough. When the temperature is too low, the heater element is automatically energized to increase the temperature of the liquid crystal device.

Abstract: A liquid crystal cell having an internal resistance-type heating means for rapid cell warm-up, and for maintaining the cell at a predetermined temperature while it is operating as a visual display. The heating means comprises electrically symmetrical transparent films of resistance material on facing surfaces of transparent members sandwiching the liquid crystal material. The resistive films are covered with an insulating film, on which is disposed the control electrodes for the electro-optic display of the liquid crystal cell. Heating voltages, higher than those required to operate the visual display, can be safely applied in parallel across the films without interfering with a concurrent visual display.