Near probe temperature

The electrical conductivity of several of these compounds has been reported.88 Compressed pellet four-probe measurements at room temperature are usually in the range 10 2-5 fl I cm-1 although a value of 150-500 has been reported for orientated polycrystals. Most of the compounds show semiconductor behaviour with activation energies of about 35 meV. Ko.6o[Ir(CO)2Cl2]-0.5H20 shows evidence of a transition to more metal-like behaviour near room temperature,88 It seems very likely that if good quality single crystals of these compounds could be obtained then they would exhibit conduction properties similar to those of the cation-deficient tetracyanoplatinates or bis(oxalato)platinates. 

Another remarkable feature of that probe is its complete independence of the reference electrode potential and nearly perfect temperature compensation. Thus, a pseudo-reference such as silver wire, functioning only as a signal return, can be used. 

The emphasis in this work has been on the acquisition of simultaneously-obtained instantaneous values of temperature and concentration, with as high a spatial resolution as practical for such experiments. The temporal and spatial resolution requirements result from the necessity to probe within (if at all possible) characteristic turbulence time and length scales. The accuracy of our experiments (which, in any case, utimately depends upon a trade-off with resolution (1)), is considered to be adequate to achieve the diagnostic goal of providing data of value to flame modelers this can be seen by comparison of the fluctuation temperature measurement uncertainty (characterized by a 5-7% standard deviation) with the broad temperature spread of the measured pdf s (extending, in Fig. 4, from values near ambient temperature to values in the vicinity of the adiabatic flame temperature). ... 

Tanaka et al measured Ne adsorption on well-crystalline AIPO4-5 at 27 K to 33 K near boiling temperature of Ne and calculated the DFT isotherm, suggesting the presence of quantum effect.[36] Thus, even Ne molecules show quantum effect. Small probe molecules such as He and H2 should show a pronounced quantum effect. 

In most recent calorimetric studies of the acid-base properties of metal oxides or mixed metal oxides, ammonia and n-butylamine have been used as the basic molecule to characterize the surface acidity, with a few studies using pyridine, triethylamine, or another basic molecule as the probe molecule. In some studies, an acidic probe molecule like CO2 or hexafluoroisopropanol have been used to characterize the surface basicity of metal oxides. A summary of these results on different metal oxides will be presented throughout this article. Heats of adsorption of the basic gases have been frequently measured near room temperature (e.g., 35, 73-75, 77, 78,81,139-145). As demonstrated in Section 111, A the measurement of heats of adsorption of these bases at room temperature might not give accurate quantitative results owing to nonspecific adsorption. 

In the methyl ether or acetate derivatives, the rotational isomers are locked at ambient temperature and second order NMR spectra are clearly seen for dimeric procyanidin derivatives (98). Probe temperatures must be increased to 160° to 180°C in nitrobenzene before the spectra collapse to first order. The (4 ff- >8)-linked isomers exhibit one preferred rotational isomer whereas two rotational isomers are evident in nearly equal proportions in the (4 S- 6)-linked compounds. In these 2, i-cis- iA trans procyanidins, the lower flavan unit is in a quasi-2iX dX position. Here the restricted rotation is due to interaction of the A-ring substituent(s) ortho to the interflavanoid bond and the C-2 hydrogen together with the n system of the A-ring of the upper unit (98). 

Abstract An Eddy current method applying a High Temperature Superconductor ( HTS ) DC SQUID sensor operating at Uquid nitrogen temperature (77K) is presented. The method is developed for the detection of surface or surface near defects. We compare the performance of the SQUID system with the performance gained from a commercial Eddy current system, while using identical probes. The experimental data are obtained on defects in gas turbine blades. The advantage of planar conformable probes for the use with the SQUID is discussed. 

Radiometry. Radiometry is the measurement of radiant electromagnetic energy (17,18,134), considered herein to be the direct detection and spectroscopic analysis of ambient thermal emission, as distinguished from techniques in which the sample is actively probed. At any temperature above absolute zero, some molecules are in thermally populated excited levels, and transitions from these to the ground state radiate energy at characteristic frequencies. Erom Wien s displacement law, T = 2898 //m-K, the emission maximum at 300 K is near 10 fim in the mid-ir. This radiation occurs at just the energies of molecular rovibrational transitions, so thermal emission carries much the same information as an ir absorption spectmm. Detection of the emissions of remote thermal sources is the ultimate passive and noninvasive technique, requiring not even an optical probe of the sampled volume. 

Recent space-probe and earth-based spectroscopic studies of the planet Venus suggest how much remains to be learned about the other planets. Earlier estimates of the surface temperature of Venus placed it near 60°C. The more detailed studies show, however, that two characteristic temperatures can be identified, —40°C and 430°C. The lower temperature is attributed to light emitted front high altitude cloud tops. The higher temperature is likely to be the average surface temperature. 

---