Shielding measurements

Sinclair, J. D., L. A. Psota-Kelty, C. J. Weschler, and H. C. Shields, Measurement and Modeling of Airborne Concentrations and Indoor Surface Accumulation Rates of Ionic Substances at Neenah, Wisconsin, Atmos. Environ., 24A, 627-638 (1990b). 

Weschler, C. J., and H. C. Shields, Measurements of the Hydroxyl Radical in a Manipulated but Realistic Indoor Environment, Environ. Sci. TechnoL, 31, 3719-3722 (1997a). 

The anisotropy of superconducting properties has further been seen in Meissner and shielding measurements from which Bd was determined [111]. The values at 50 mK for (TMTSF)2C104 are 0.02 mT, B i 0.1 mT, and Bd 1 mT. Together with the values for the upper critical fields the anisotropic GL parameter Ki can be calculated by... 

Arrhenius arrived at the value i i x lO from Shields measurements of the hydrolysis of salts. 

Nitrogen chemical shifts in 14N NMR spectroscopy have been used to estimate the equilibrium compositions of a series of mercaptopyridines in solution. Thus, ca. 95% of the thione form was estimated for 2-mercaptopyridine in acetone and methanol and for 4-mercaptopyridine in methanol and acetone/DMSO (790MR379). 15N NMR shielding measurements provided the quantitatively reliable estimates of tautomeric equilibria for 3-methoxycarbonyl-2-mercaptopyridine and 3-mercaptopyridine. The equilibrium of 3-methoxycarbonyl-2-mercaptopyridine is shifted predominantly to the thione tautomer (95%), whereas 3-mercaptopyridine exists in the thiol form (at least 94%) (85MRC790). By 13C NMR spectroscopy, 3-nitropyridine-4-thiol exists in the thiol form (86H(24)1301). Another NMR criterion, used for estimation of the tautomeric equilibrium in mercaptopyridines, is based on 3/(ch) values for the CN-CH, C N = CH, and C = N-CFI structural elements (83OMR20). 

It is unclear at this time how the light sensitivity of OTFTs compares to silicon-based TFTs, but it is certain that similar light-shielding measures must be employed. Studies in our laboratory have shown that, in addition to the photocurrents generated by incident illumination, long-lived light-induced threshold shifts can occur in pen-... 

S. Bruckenstein and P. R. Gifford [Anal. Chem., 51, 250 (1979)] proposed that ring electrode shielding measurements at the RRDE could be employed for the analysis of micromolar solutions by using the equation... 

In addition to the above experimental holes, twelve 2-in.-I.D. holes are provided in the concrete. These holes, designated VC-1 through 9 and VC-11 through 13, penetrate the south wall of the biological shield to elevation 92 ft. Their location is indicated in Fig. 3.E around the south instrument cubicle (to the right of GM-1) and between the cubicle and the outer edge of the reactor top. It is expected that these holes will.be useful for thermocouples or for shielding measurements. 

N. E Colaneri, L. W. Schacklette, EMI Shielding Measurements of Conductive Polymer Blends. IEEE Trans. Instrum. Meas. 1992,41,291-297. 

T. Taka, EMI Shielding Measurements on Poly(3-Octyl Thiophene) Blends. Synth. Met. 1991,41,1177-1180. 

Experimentally, shielding effectiveness is measured using instrument called network analyzer (NA). Both scalar NA (SNA, which record only the magnitude of the incident, reflected, and transmitted signals) and vector NA (VNA, which also measures the associated phases) are used for shielding measurements [1,3]. Particularly, the VNA signals carry information about attenuation constant as well as dielectric/magnetic properties. 

A good agreement between theoretical and experimental shielding measurements (inset of Figure 9.21b) was also observed. In another study (Figure 9.22), the role of highly reflecting planes of PANl-M WCNTs... 

Automatic Calorimetry.— Before the development of modem electronic techniques, precise measurements of heat capacities were made by manual methods both for control of adiabatic conditions and for measurements of temperatures and electrical energies. Typical examples of such measurements have been described by Southard and Brickwedde and by Ruhrwein and Huffman. To obtain the highest possible accuracy, the measurement required two operators, and, to cover the temperature range (10 to 300 K), a large number of potentiometric observations were necessary. It is now usual to have automatic control of the adiabatic shield. Measurements of temperature and energy with a manually-operated potentiometer can be simplified by the use of constant current supplies for the potentiometer and thermometer circuits. 

The isotropic shielding is the shielding measured if we average the effect over all relative orientations of the molecule in the field. This is what we expect to observe if we have a sample where the molecule is found at many random orientations, as in the gas or liquid phases. The isotropic shielding is equal to... 

C. Analysis of Results of EBR Shielding Measurements -J. W. Butler, M. Grotenhuis... 

Experimental Breeder Reactor Shield Measurements," Reactor Shielding Information Meeting, Chicago, November 12 and 13, 1953, WASH-152, March, 1954, pp. 34-35. 

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