Recent Experimental Results

Nearest neighbor covalency effects in transition metal systems are normally described by the two Racah parameters B and C. Qualitatively, reductions in B and C are predicted to occur with pressure due to enhancements in covalency expected from increased metal-ligand orbital overlap as the nearest neighbor bond length decreases. In order to assess the effect of pressure on B and C, the effect of pressure on Dq needs to be known or transitions whose energies are independent or approximately independent of Dq need to be considered. The effect of pressure on Dq will be considered below and can be determined experimentally. If suitable spectroscopic data in absorption and/or emission is available, it is therefore possible to determine the effect of pressure on B and C. 

Experimental consideration of the effect of pressure on B and C has focused on the R line ( E — A2) emission of Cr + in ruby because of the availabiUty of extensive ruby R line pressure calibration data (see Sect. 2.2.1). In regular octahedral symmetry, over the range of values 1.5 Dq/B 3.5 and 3 C/B 5 normally encountered for Cr +, the energy of the E A2 transition is given approximately by [134] 

Although there is some variation in the literature [93, 144,145], the ambient pressure parameter values for ruby are generally taken to be B -650 cm C -3200 cm and Dq -1810 cm [134,146,147]. From Eq. (5), we therefore see that the Dq dependent contribution accounts for less than 3 % of the E energy at ambient pressure and that, to a reasonable approximation, the E energy is determined by B and C at ambient pressure. Since Dq increases with pressure (see below), the approximation remains valid at high pressure. 

Host lattice or complex (nm (1, ) Pressure range (kbar) T(K) Ref. 

Other evidence of weak variations of B with pressure is found in absorption and emission studies of d (Mn +, Fe +) and d (Cr +, Mn +) systems. In high spin octahedral d systems, the energy of two visible absorption transitions are independent of Dq  

---

The toroidal and helical forms that we consider here are created as such examples these forms have quite interesting geometrical properties that may lead to interesting electrical and magnetic properties, as well as nonlinear optical properties. Although the method of the simulations through which we evaluate the reality of the structure we have imagined is omitted, the construction of toroidal forms and their properties, especially their thermodynamic stability, are discussed in detail. Recent experimental results on toroidal and helically coiled forms are compared with theoretical predictions. 

In conclusion, wc have shown the interesting information which one can get from electrical resistivity measurements on SWCNT and MWCNT and the exciting applications which can be derived. MWCNTs behave as an ultimate carbon fibre revealing specific 2D quantum transport features at low temperatures weak localisation and universal conductance fluctuations. SWCNTs behave as pure quantum wires which, if limited in length, reduce to quantum dots. Thus, each type of CNT has its own features which are strongly dependent on the dimensionality of the electronic gas. We have also briefly discussed the very recent experimental results obtained on the thermopower of SWCNT bundles and the effect of intercalation on the electrical resistivity of these systems. 

Anderson, R. P., and D. R. Armstrong, 1973, Comparison between Vapor Explosion Models and Recent Experimental Results, AIChE Preprint 16, 14th Natl. Heat Transfer Conf., Atlanta, GA. (2)... 

Hoffman, H. W., 1964, Recent Experimental Results in ORNL Studies with Boiling Potassium, Third Annual Conf. on High Temperature Liquid Metal Heat Transfer Technology, Oak Ridge Natl. Lab., Oak Ridge, TN, ORNL-3605, vol. 1, pp. 334 350. (4)... 

Recent experimental results indicate that photosynthesis probably does indeed result from a scheme similar to the one presented above, although a large number of the individual participants in the scheme remain unknown to date. Let us now briefly review these experimental findings. 

Attempts have recently been made to link the RNA world with the lipid world. Two groups involved in RNA and ribozyme research joined up with an expert on membrane biophysics (Szostak et al., 2001). They developed a model for the formation of the first protocells which takes into account both the most recent experimental results on replication systems and the self-organisation processes of amphiphilic substances to give supramolecular structures. 

Figure 17 shows recent experimental results for modulation index changes, in response to changing C02 gas concentration in the measurement cell18. 

This paper reviews the recent experimental results and mathematical modeling from the literature on electrocodeposition of particles in a metallic matrix. Although many different particle/metal systems are discussed, the electrocodeposition of alumina particles in copper matrix is highlighted as this widely-studied system illustrates the various effects of process variables and it exemplifies the types of contradictions concerning these results in the literature. 

Recent experimental results are summarized in Table III. The catalyst used here was molybdenum supported on Cab-O-Sil. We have experienced difficulty in repeating the previous results, which indicated that up to 50% selectivity to methanol could be achieved even at conversions of -15% (18). In the more recent study it has been possible to obtain this selectivity only at conversions of 1%. Nevertheless, at sufficiently low conversions methanol is the principal product, provided steam is present in the system. 

Abstract. Recent experimental results in culture and in vivo are summarized that show the existence of developmental relationships between cells that build up blood vessel walls and some previously unrelated tissues and organs. It was formerly demonstrated, in lower vertebrates as well as mammals, including humans, that discrete subsets of blood-forming endothelial cells play a key role in the emergence of the definitive hematopoietic system. We have also documented the existence in human skeletal muscle of endothelium-borne, extremely potent myogenic progenitor cells. Einally, we have characterized and purified perivascular cells - or pericytes - from human tissues and... 

Recent experimental results on thermodynamic properties of high pressure supercritical fluids have opened up the possibility to study combustion and flames at very high pressures and in unusual environments. Stationary diffusion flames have been produced up to 2000 bar in dense aqueous mixed fluid phases. 

PossibiKties of electrocatalysis of reactions at electrodes are among the powerful incentives for the electrochemical study of POMs. Interesting results were obtained both in electrocatalytic reductions and oxidations, provided the appropriate form of the POM is used. Two recent reviews devoted to the electrochemical properties of polyoxometalates as electrocatalysts are available [8, 9]. The second one focuses more specifically on electrocatalysis on modified electrodes. In the present text, attention will be drawn specially to the basic principles that could be considered to govern most of solution processes. The principles will be illustrated by several recent experimental results, even though earlier achievements will also be described briefly. 

In the following section a brief survey of our recent experimental results obtained with CIS is presented. 

---