摘要:

In this paper, it is shown how a heat‐flow transducer and a digital electronic unit can be used together for simultaneous measurements of heat flow and temperature. The electrical output of the sensor consists of a voltage generator (whose open circuit voltage is proportional to the rate of the heat flow to be measured). The electrical output of the sensor acts as a single battery and metallic resistors were disposed between the terminals. The open circuit voltage is proportional to the rate of heat flow to be measured. The value of the resistor is controlled by temperature. The procedure for simultaneously measuring heat flow and temperature is made straightforward by including a balanced Wheatstone bridge driven by an ac carrier as an integral part of the design. To solve the difficult problem of precise detection and maintenance of the balance, the classical Wheatstone bridge configuration has been slightly modified by adding a capacitor to smooth the phase variations around the balance. The discrete time feedback loop used for automatically balancing the bridge includes a digital integrator which sums the phase errors and provides the required voltage. As a result, temperature measurements were made with a linearity better than 1% in the measuring range and the digital readout is obtained with a rise time of 10 ms.

ISSN:0034-6748    

DOI:10.1063/1.1137377

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Meteorological observations may be more profoundly exploited by digitalization and the application of modern statistical methods. These techniques impose more rigorous conditions on the measuring devices; the results may be biased by aliasing or by the frequency response of the measuring instrument itself. Most heat fluxmeters, used in radiometry, do not respond in the same way as a filter with lumped parameters and as a consequence the compensation of their frequency response by electronic filtering is not straightforward. A method to approach the response of this type of sensor by a filter with judicious chosen poles and zeros is described and compensation is obtained by the inversion of this filter. In this way the bandwidth of a particular thermal fluxmeter was increased from 0.07 to 5 Hz.

ISSN:0034-6748    

DOI:10.1063/1.1137378

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A radiant zone heater based on molybdenum disilicide wire and a machinable alumina support/reflector is described for use with materials with liquidus temperatures in the range of 600 ° and 1200 °C.

ISSN:0034-6748    

DOI:10.1063/1.1137379

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

An optical position‐sensitive detection system was added to a McPherson ESCA‐36 x‐ray photoelectron spectrometer. The system contains a multichannel electron multiplier and vidicon TV camera and operates 250 times faster than the original single‐channel electron multiplier.

ISSN:0034-6748    

DOI:10.1063/1.1137380

出版商:AIP    

年代:1983

数据来源: AIP