Gap conductance

Bunz et al. pointed out that it would be of interest to develop materials that combine the stability, electron affinity, and high emissive quantum yield of PPEs with the excellent hole injection capabilities of poly(p-phenylene vinylene)s (PPVs) [48]. In line with this notion,recent synthetic activities have focused on the engineering of the band gap, conduction band, and valence band of PAEs with the objective to render these materials more useful for practical applications that exploit their electrically (semi)conducting nature. Examples of materials that emerged from these efforts are discussed in detail in other portions of this volume (in particular the chapters by Bunz, Klemm, and Yamamoto). They include, among others, poly(heteroarylene ethynylenes) such... 

The air electrode consists of an insulated metal wire with its tip 1-2 mm above the liquid surface and with polonium deposited on the tip to make the air gap conducting. 

Volta potentials are potentials Just beyond the range of chemical forces so that the work of transfer of a charge from a reference at infinite distance, but in the same phase, to the point where yf is measured, is purely electrostatic. For a phase a in contact with air, y/ is obtainable by bringing an electrode just outside the surface, making the gap conducting by adding a radioactive ionic substance. See flg. 3.38, point A and fig. 3.75. Similarly, y/ is the Volta potential in B, and y/ - y/ = v (B)- v/(A). Further, is the Volta potential at E, etc. 

An evidence-based practitioner mnst understand the patient s circumstances or predicament identify Icnowledge gaps and frame questions to fill those gaps conduct an efficient literature search critically appraise the research evidence and apply that evidence to patient care. ... 

Arrhythmias occur within a few seconds after reperfusion, following ischemic periods of 10-30 min long. They start by a spontaneous stimulus in the reperfused zone and change afterward in a re-entry multiple wavelet type of ventricular tachycardia (VT) or ventricular fibrillation (VF). Extremely short action potential, short refractory period and slow conduction are the main contributing factors. Increased hyperpolarization and elevated intracellular calcium that act negatively on gap conductance impair conduction. Unidirectional conduction is favored by the marked heterogeneity in extracellular potassium, action potential and refractory period. The extra stimulus is initiated in the reperfused zone, probably by early (EAD) and late (DAD) afterdepolirizations. 

The gap conductance model for conforming rough surfaces was developed, modified, and verified by Yovanovich and co-workers [35,73,100-104]. The gap contact model is based on surfaces having Gaussian height distributions. It also accounts for the mechanical deformation of the contacting surface asperities. The development of the gap conductance model appears in several papers [139,143,147]. 

Wesley and Yovanovich [127] compared the predictions of the proposed gap conductance model and experimental measurements of gaseous gap conductance between the fuel and clad of a nuclear fuel rod. The agreement was very good and the model was recommended for fuel pin analysis codes. 

Gap Conductance Correlation Equations. Although the gap integral can be computed accurately and easily by means of computer algebra systems, Negus and Yovanovich [73] proposed the following correlation equations for the gap integral ... 

Fourier number based on square root of area critical value of Fourier number radiative parameter for point contact elastoplastic contact parameter gap conductance correlation equation metric coefficients, jacobian height of single and double cones Rockwell C hardness number Brinell hardness... 

K. J. Negus and M. M. Yovanovich, Correlation of Gap Conductance Integral for Conforming Rough Surfaces, Journal of Thermophysics and Heat Transfer (2) 279-281,1988. 

S. Song, M. M. Yovanovich, and F. O. Goodman, Thermal Gap Conductance of Conforming Rough Surfaces in Contact, Trans. ASMEJ. Heat Transfer (115) 533-540,1993. 

M. M. Yovanovich, J. DeVaal, and A. A. Hegazy, A Statistical Model to Predict Thermal Gap Conductance Between Conforming Rough Surfaces, AIAA-82-0888, AlAAIASME Third Joint Thermophysics, Fluids, Plasma and Heat Transfer Conference, St. Louis, MO, June 1982. 

Lee, K., Sotzing, G.A., 2001. Poly(thieno[3,4-b]thiophene). Anew stable low band gap conducting polymer. Macromolecules 34, 5746-5747. 

Staes, E., et al. 1999. Properties of a low band gap conducting polymer electrode used for amperometric detection in liquid chromatography. Electroanalysis 11 65. 

Taliani, C., et al. 1989. Optical properties of a low energy gap conduction polymer Poly-dithieno [3,4-b 3, 4 -d] thiophene. Synth Met 28 C507. 

Huang, H. and P.G. Pickup. 1997. In situ conductivity of a low band-gap conducting polymer Measurement of intrinsic conductivity. Acta Polym 48 455. 

Loganathan, K., et al. 2003. A -dicyclopentajl.l-frS.L-l/ldithiophene. A conjugated bridging unit for low band gap conducting polymers. Chem Mater 15 1918. 

Cheng, H. and R.L. Elsenbaumer. 1995. New precursors and polymerization route for the preparation of high molecular mass poly(3,4-dialkoxy-2,5-thienylenevinylene)s Low band gap conductive polymers. / Chem Soc Chem Commun 1451. 

Lee, B., V. Seshadri, and G.A. Sotzing. 2005. Water dispersible low band gap conductive polymer based on thieno[3,4-b]thiophene. Synth Met 152 177-180. 

I. T. Kim, R. L. Elsenbaumer, Synthesis, characterization, and electrical properties of poly(l-alkyl-2,5-pyrrylene vinylenes) New low band gap conducting polymers, Macromolecules 2000, 33, 6407... 

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