Key problems

The relation between the microscopic friction acting on a molecule during its motion in a solvent enviromnent and macroscopic bulk solvent viscosity is a key problem affecting the rates of many reactions in condensed phase. The sequence of steps leading from friction to diflfiision coefficient to viscosity is based on the general validity of the Stokes-Einstein relation and the concept of describing friction by hydrodynamic as opposed to microscopic models involving local solvent structure. In the hydrodynamic limit the effect of solvent friction on, for example, rotational relaxation times of a solute molecule is [ ]... 

A lot of analytical techniques have been proposed in recent decades and most of them are based on enzymes, called dehydrogenases, which are not sensitive to oxygen and need cofactors such as NAD". The key problems which seriously hamper a wide commercialization of biosensors and enzymatic kits based on NAD-dependent enzymes are necessity to add exogenous cofactor (NAD" ) into the samples to be analyzed to incorporate into the biologically active membrane of sensors covalently bounded NAD" to supply the analytical technique by NAD -regeneration systems. 

There is a risk that the O-ring will not maintain its proper orientation in the cover recess during subsequent assembly processes, and therefore may not be correctly positioned on final assembly. Restricted vision of the inside of the cover is the key problem here. 

A key problem in experimental load analysis is the translation of the data yielded from the measurement system (as represented by the load histories in Figure 4.21) into an... 

A second key problem is to devise means to separate the tubes from the soot and metal particles, either chemically or mechanically. This is an essential step towards manipulation and thorough characterization of these materials. Recently, it was reported that a significant fraction of the metal particles could be removed from the sample by vacuum annealing it at... 

A key problem in the equilibrium statistical-physical description of condensed matter concerns the computation of macroscopic properties O acro like, for example, internal energy, pressure, or magnetization in terms of an ensemble average (O) of a suitably defined microscopic representation 0 r ) (see Sec. IVA 1 and VAl for relevant examples). To perform the ensemble average one has to realize that configurations = i, 5... 

Experimental information for polymeric LED is sparse. A key problem for conventional lime-of-flighl studies is that the condition of generating a sheet of carriers whose spatial extension is small compared to the thickness of a = 100 nm film is difficult to meet. On the other hand, thick films fabricated, for instance, by solvent casting rather than by spin coating, may differ regarding their morphology and, concomitantly, the built-in-disorder. On the fundamental side, transport in... 

In the numerical work there is also another key problem, namely the calculation of the matrix elements HKL, the number of which is... 

Although the electrostatic field on the polyelectrolyte surface effectively impedes back ET, it is unable to retard very fast back ET or charge recombination of the primary ion pair within the photochemical cage. The overall quantum yield of photoinduced ET is actually controlled in most cases by the charge recombination. Hence, its retardation is the key problem for attaining high quantum yields in the photoinduced ET. 

We have included in this volume two chapters specifically related to society s kinetic system. We have asked James Wei of the University of Delaware, recent Chairman of the consultant panel on Catalyst Systems for the National Academy of Sciences Committee on Motor Vehicle Emissions, to illustrate key problems and bridges between the catalytic science and the practical objectives of minimizing automobile exhaust emissions. We have also asked for a portrayal of the hard economic facts that constrain and guide what properties in a catalyst are useful to the catalytic practitioner. For this we have turned to Duncan S. Davies, General Manager of Research and Development, and John Dewing, Research Specialist in Heterogeneous Catalysts, both from Imperial Chemical Industries Limited. 

The aim of this review article is to discuss the type of information which can be obtained concerning orientation in polymers by spectroscopic methods and to select examples which illustrate key problems in the area of polymer physics. 

Although the LD model is clearly a rough approximation, it seems to capture the main physics of polar solvents. This model overcomes the key problems associated with the macroscopic model of eq. (2.18), eliminating the dependence of the results on an ill-defined cavity radius and the need to use a dielectric constant which is not defined properly at a short distance from the solute. The LD model provides an effective estimate of solvation energies of the ionic states and allows one to explore the energetics of chemical reactions in polar solvents. 

Abstract Either because observed images are blurred by the instrument and transfer medium or because the collected data (e.g. in radio astronomy) are not in the form of an image, image reconstmction is a key problem in observational astronomy. Understanding the fundamental problems underlying the deconvolution (noise amplification) and the way to solve for them (regularization) is the prototype to cope with other kind of inverse problems. 

The mechanism of TFL can be summarized to the ordered him lubrication, concluded from previous researches. It should be noted that the property and mechanism of TFL are not fully understood to date, and there remains a wide blank area to be covered between experiments and theoretical predictions and it leaves a far cry to achieve predictive ability. Some key problems associated with theoretical modeling which need to be addressed are ... 

Here we describe an EP study of catalytic NO reduction by CO and by propene over Pt/P alumina. The latter process is especially significant for the removal of NO in oxidising environments, a key problem that must be overcome for pollution abatement from lean-bum gasoline engines. 

Key problems of the original route were effectively addressed. 

There are several key problems. One, is the long term availability of fossil fuels which today supply some eighty per cent of world energy. 

The point is that there are no technical nuclear problems without rational solutions. The key problems are public misconceptions and the resulting institutional impediments which can impact on the potential of nuclear energy to meet future world needs. 

ER E, the S T organization of the World largest oil company, ExxonMobil, was not very prolific in R D activities related to biocatalytic refining, but was focused on addressing a few key problems identified in BDS. They began in early 1990, with works on gas treatment however, the developments took an oil twist towards the end of the decade when they became involved with heavier hydrocarbon feedstocks. This company possesses inventions, which are protected with six patents ... 

Sucessful application of the air electrode requires solving some key problems the air electrode catalyst, the alkaline electrolyte carbonization, the oxygen reaction with anode materials, an influence of an air humidity on an electrode behavior. 

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