Device under test temperature

The temperature dependence of the fabricated open cavity FP device was evaluated experimentally. The sensor was placed in a programmable electric tubular furnace. The temperature of the furnace was increased from room temperature to 1,100°C at a step of 50°C. The cavity length as a function of the temperature is plotted in Fig. 7.11, where it increased nearly linearly following the increase of temperature. The temperature sensitivity of the particular FP device under test was estimated to be 0.074 nm °C 1 based on the linear fit of the measurement data. The equivalent coefficient of thermal expansion (CTE) of the fiber FP device was 2.4x10 6oC. ... 

In the fiber-optic thermometry probe technique, a temperahue sensor, consisting of a small amount of a temperature-sensitive material (manganese-activated magnesium fluorogermanate), is mounted on the end of a probe and is placed on the surface of the device under test (DUT). A filtered xenon flash lamp provides a blue-violet light to excite the phosphor on the probe to fluoresce. When excited by this wavelength of light, the phosphor in the sensor exhibits a deep red fluorescence. 

Figure 10.4 Quadrant display of a device under test showing (a) unpowered radiance, (b) powered radiance, (c) emissivity, and (d) "true temperature" (courtesy of Quantum Focus Instruments, Inc.).

Dirt and moisture are the worst enemies of the performance of all PD gas meters, so inlet filtering should be used when indicated. Pressure and temperature should either be controlled or compensated. The testing (or proving, as it is called in the gas utility industry) of gas meters is usually done by an accurately calibrated "bell" of cylindrical shape that is sealed in a tank by a suitable liquid. The lowering of the bell discharges a known volume of air through the meter under test. Other standards used to calibrate gas meters are calibrated orifices and critical flow nozzles. These devices compare rates of flow rather than fixed volumes. 

Figure 5 shows the performance of encapsulated devices under the high temperature storage device test. The conditions of this test are as follows storage in standard convection oven 0 200°C, no induced humidity, and no bias. Test results indicate that the encapsulant based on the stable bromine CEN took greater than 52 weeks to reach 50% failure that is, 50% of the initial number of devices have failed, in contrast to the standard high purity resin encapsulant which failed at 14 weeks. 

Plasma treatment was performed on Balzers SCD 050 device under the following conditions gas purity was 99.997%, flow rate 0.3 1/s, pressure 10 Pa, electrode distance 50 mm and its area 48 cm, chamber volume approx. 1000 cm, plasma volume 240 cm. Exposure times differ for individual tested polymer foils and individual consequent modifications from 15 to 500 s, discharge power was 3.8 or 8.3 W and the treatment was accomplished at room temperature [12]. 

In most weathering devices, the approximate temperature of dark colored specimens is simulated and regulated with the use of a black panel sensor of either the uninsulated or insulated type described in ASTM G151 (61). It serves to control the air temperature which, in combination with the surface heat caused by absorbed radiation, provides the black panel temperature specified in the test method. The heat due to absorbed radiation depends on the visible and infrared absorption properties of the materials as well as on the SPD and irradiance of the source. Generally, the black panel temperature that specified is the maximum temperature that dark samples attain under use conditions. Currently, the highest black panel temperature specified is 89°C during the light-only period in a xenon arc device used for tests on automotive interior materials such as seat covers and dashboards (62). 

System noise temperature The equivalent temperature of a passive device yielding the same thermal noise power per unit bandwidth as the system under test. 

Bias is frequently added for testing of electronic devices, printed wiring boards, and assemblies of electronic equipment. The 85°C, 85 % RH, bias test has been the predominant one in electronics for many years [8], While it sometimes misses failure mechanisms that later occur in the field, it also finds many weak points in new products. It is especially useful for quality control of seasoned devices for which long-term reliability is known to be high if the product passes this test. There are many commercial suppliers of temperature/humidity/bias test chambers and software is widely available to automate the operation, data collection, and data interpretation. Attention to data management is mandatory when hundreds of devices are tested simultaneously. This is frequently required in electronics to obtain sufficient data to make statistically valid predictions of lifetime and failure rate under use conditions. 

However, a great amount of work remains. Firstly, comprehensive reliabihty, durabihty, as well as environmental impact tests, e.g., vibration, temperature cycHng, and aging, are needed, since it is indeed a new way of fabricating passive electronic devices, with new materials. Electrical characteristics of this type of soft electronics under extreme temperature... 

The radiation and temperature dependent mechanical properties of viscoelastic materials (modulus and loss) are of great interest throughout the plastics, polymer, and rubber from initial design to routine production. There are a number of laboratory research instruments are available to determine these properties. All these hardness tests conducted on polymeric materials involve the penetration of the sample under consideration by loaded spheres or other geometric shapes [1]. Most of these tests are to some extent arbitrary because the penetration of an indenter into viscoelastic material increases with time. For example, standard durometer test (the "Shore A") is widely used to measure the static "hardness" or resistance to indentation. However, it does not measure basic material properties, and its results depend on the specimen geometry (it is difficult to make available the identity of the initial position of the devices on cylinder or spherical surfaces while measuring) and test conditions, and some arbitrary time must be selected to compare different materials. 

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