Dual-source

The wide use of p-block and early transition metal chalcogenide materials for electronics applications (semiconductors, semi-metals, battery materials, etc.) has resulted in a large amount of work concerned with CVD using mixtures of metal halides and chalcogenoethers as dual source precursors and preformed complexes as single sources.166... 

As we have seen, however, the circulation of money also plays a pivotal role in the reproduction schema. Without borrowing from the financial system expanded reproduction is not possible. Investment is exogenous, financed not out of the pockets of capitalists, but by the financial system. Embedded in the tension, established by Domar, between investment as a dual source of capacity and demand, is a fragile network of credit relationships between capitalists and banks. Marx s reproduction schemes expose the stringent conditions on the finance and realization of investment that are required for balanced growth. Since these conditions are unlikely to be met - supply is unlikely to create its own demand - a refutation of Say s Law is offered by the reproduction schema. 

Nafie LA, Buijs H, Rilling A et al (2004) Dual source Fourier transform polarization modulation spectroscopy an improved method for the measurement of circular and linear dichroism. Appl Spectrosc 58 647-654... 

With some instruments, the instability of the analyser is such that there is a drift in mass on relatively short times, say less than 1 day. When this drift is large, the use of an internal standard or a dual source to inject ions alternately from the sample and from the standard is needed. The first solution increases the number of ions in the analyser, and thus the importance of the space charge effect. The second increases the acquisition time. Frequent recalibration of the spectrometer may also be required. If the instrument is stable, a lock mass can be used either from a compound added to the sample or from a known ion from the solvent or the background. 

Petroleum and low-temperature combustion processes yield primarily highly alkylated PAHs, while high-temperature combustion sources result in many nonalkylated PAHs. If this is generally the case, we must conclude, from an examination of the data in Figures 5-11, that the PAHs in these samples generally have dual sources or that they have undergone substantial biochemical and/or physical modifications. If petroleum is a... 

Sundarapandian, S. May, J.C. McLean, J.A., Dual source ion mobility-mass spectrometer for direct comparison of electrospray ionization and MALDI coUision cross section measurements. Anal. Chem. 2010, 82, 3247-3254. 

Klotz, D. and Chatteijee, K. (1995). Dual sourcing in repeated procurement competitions. Management Science, 41(8) 1317-1327. 

Tyworth, J. E. and A. Ruiz-Torres. 2000. Transportation s role in the sole- versus dual-sourcing decision. International Journal of Physical Distribution and Logistics Management. 30(2) 128-144. 

Dual sourcing—Use of two or more suppliers for critical parts is commonly used to avoid supply disruptions. HP follows the portfolio approach to vendors by maintaining a mix of suppliers from different geographic regions. 

Achenbach S, Ropers D, Kuettner A et al (2006) Contrast-enhanced coronary artery visualization by dual-source computed tomography - initial experience. Eur J Radiol 57 331-335... 

After the introduction of multislice CT in 1992 with the advent of dual-slice scanners, this technology was improved in 1998 by the implementation of 4-slice, in 2000 with 8-slice, in 2002 with 16-slice, and in 2004 with 64-slice scanners. Development continues and at the turn of 2006 the first 64-slice dual-source devices with a very high temporal and spatial resolution were installed thus one seems to observe a 2-year cycle for the launch of new CT... 

The conventional solution would have been to make rectangular units by ordinary metal pressing methods, and this was done by competitors, mainly Continental ones, with purpose-designed plant. For Lucas simply to follow suit would have involved a considerable new investment, and a late entry into the market. There was some investment of this type because customers adopted a conservative approach, and specified steel and required dual sources of supply. But the main effort went towards a new concept, which offered technical advantage. 

Air filtration, the real heart of the system, was a major concern for the safety community. It was necessary to build in redundancy with every major component to ensure a fail-safe system. This consisted of dual High Efficiency Particulate Air (HEPA) and carbon filters, dual vacuum gauges, dual air pressure alarms, dual motor blowers to draw air through the glovebox, dual sources of electricity and a Hame Photometric Detector (FPD) to monitor between the carbon beds for possible breakthrough of chemical compounds. This was necessary because the effluent air from the filter beds was being released into the working environment of the operators. Army... 

Conventional instrument geometries incorporate a source, prism or grating to disperse the light from the source, a detector, and necessary accessories such as lenses, mirrors, sample holders, and movable slits. If the spectral range of the instrument extends beyond the visible into the near-infrared and ultraviolet, dual sources, detectors, and ancillary electronics are required. The Perkin-Elmer Lambda 19, diagramed in Fig. 2, is an example of this technology (37). 

Fig. 1.5a,b. Schematic illustration of a dual-source CT (DSCT) system using two tubes and two corresponding detectors offset by 90°. A scanner of this type provides temporal resolution equivalent to a qiuirter of the gantry rotation time, independent of the patient s heart rate. In a technical realization, one detector (a) covers the entire scan field of view with a diameter of 50 cm, while the other detector (b) is restricted to a smaller, central field of view... 

Fig. 1.6. Case study illustrating the clinical performance of dual-source CT (DSCT) for ECG-gated cardiac imaging. VRT renderings of a 59-year-old male patient with suspicion of RCA stenosis. The mean heart rate of the patient during the scan was 85 bpm. Left Diastolic reconstruction at 65% of the cardiac cycle. Right End systolic reconstruction at 28% of the cardiac cycle. In both cases the coronary arteries are clearly depicted with few or no motion artifacts...

With the development of Dual Source CT, simultaneously acquired Dual Energy CT has become feasible in a clinical setting. Running both x-ray tubes at different potentials, different x-ray spectra can be obtained. Thus, elements with a strongly energy dependent absorption such as iodine or xenon gas can be differentiated from other materials. A three material decomposition algorithm is apphed to map the distribution of such a substance in a CT image. 

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