Pumping process

Resonant processes of some importance include resonant electronic to electronic energy transfer (E-E), such as the pumping process of the iodine atom laser... 

It has been said tliat anytliing will lase if pumped witli enough energy, but tire efficiency of tire pumping process is important for practical, economical devices. In tliis regard two-level lasers are of little interest because, except under extraordinary pumping conditions, one can only equalize tire populations of tire upper and lower levels. A... 

Diatomic molecules have only one vibrational mode, but VER mechanisms are paradoxically quite complex (see examples C3.5.6.1 and C3.5.6.2). Consequently there is an enonnous variability in VER lifetimes, which may range from 56 s (liquid N2 [18]) to 1 ps (e.g. XeF in Ar [25]), and a high level of sensitivity to environment. A remarkable feature of simpler systems is spontaneous concentration and localization of vibrational energy due to anhannonicity. Collisional up-pumping processes such as... 

Cryogenic distillation has been used extensively ia the processiag of natural gas for nitrogen removal and for helium recovery (22—23). Two basic processes are now used for nitrogen rejection from natural gas— the single-column heat-pumped process and the double-column process. Eadier processes utilized multistage flash columns for helium recovery from natural gas (24). 

Fig. 8. Single-column heat pumped process for nitrogen rejection.

Positive-displacement pumps are subject to flow instability, which is created either by process restrictions or by the internal pumping process. Increases in amplitude at the passing frequencies, as well as harmonics of both shafts running speed and the passing frequencies, typically result from instability. 

Normally associated with bladed or vaned machinery such as fans and pumps, process instability creates an unbalanced condition within the machine. In most cases, it excites the fundamental (lx) and bladepass/vanepass frequency components. Unlike true mechanical imbalance. 

An important specific feature of the present experiment is worth noting. The X-ray photons have energies that are several orders of magnitude larger than those of optical photons. The pump and probe processes thus evolve on different time scales and can be treated separately. It is convenient to start with the X-ray probing processes, and treat them by Maxwellian electrodynamics. The pumping processes are studied next using statistical mechanics of nonlinear optical processes. The electron number density n(r,t), supposed to be known in the first step, is actually calculated in this second step. 

In these systems the converter is producing waste heat, which has to be released to the ambient connected to an entropy flow caused by the irreversibilities within the converter. The discharging process will be a heat pump process, where the entropy has to be taken from the ambient. Therefore it is obvious that these systems have to be coupled to the ambient conditions. Such a storage is not self-sufficient. These systems are called indirect thermal energy storages. 

Note that the usage of 10-fs laser pulse leads to rich oscillatory components as well as these rapid kinetics in their pump-probe time-resolved profiles. Obviously in this timescale, the temperature T will have no meaning except for the initial condition before the pumping process. In addition, such oscillatory components may be due not only to vibrational coherence but also to electronic coherence. A challenging theoretical question may arise, for such a case, as to how one can describe these ultrafast processes theoretically. 

The above theory is usually called the generalized linear response theory because the linear optical absorption initiates from the nonstationary states prepared by the pumping process [85-87]. This method is valid when pumping pulse and probing pulse do not overlap. When they overlap, third-order or X 3 (co) should be used. In other words, Eq. (6.4) should be solved perturbatively to the third-order approximation. From Eqs. (6.19)-(6.22) we can see that in the time-resolved spectra described by x"( ), the dynamics information of the system is contained in p(Af), which can be obtained by solving the reduced Liouville equations. Application of Eq. (6.19) to stimulated emission monitoring vibrational relaxation is given in Appendix III. 

The dynamical behaviors of p(At) v and p(At)av av, have to be determined by solving the stochastic Liouville equation for the reduced density matrix the initial conditions are determined by the pumping process. For the purpose of qualitative discussion, we assume that the 80-fs pulse can only pump two vibrational states, say v = 0 and v = 1 states. In this case we obtain... 

Let us also anticipate that, if a vacuum chamber initially contains air at the atmospheric pressure (with a typical composition like that reported in Table 1.2), during the pumping process the composition remains approximately the same in the low-vacuum range. Then, the composition changes, becoming usually richer in light molecules. 

The pumping process reduces the mass of liquid in the reservoir from to m and the temperature from 7) to T ... 

A pumping process, to excite those atoms (molecules, ions, etc.) up to higher quantum energy levels to produce population inversion. 

It is clear that in order to get stimulated emission, a pumping process is required to excite the system into its high quantum energy level. Real materials can be pumped in many ways, as will be mentioned later. For laser action to occur, the pumping process must produce not merely excited atoms, but the condition of population inversion. 

In various kinds of industrial production, materials need to be treated with charged colloidal particles. In such systems, the value of the zeta-potential analyses are needed to control production. For example, in paper, adhesive, and synthetic plastics, colloidal clay can be used as filler. In oil drilling, clay colloidal suspensions are used. The zeta potential is controlled so as to avoid clogging the pumping process in the oil well. It has been found that, for instance, the viscosity of a clay suspension shows a minimum when the zeta potential is changed (with the help of pH from 1 to 7) from 15 to 35 mV. Similar observations have been reported in coal slurry viscosity. The viscosity was controlled by the zeta potential. 

If S remains constant during the pumping process, then one can use the difference quotient instead of the differential quotient ... 

Shown schematically in Fig. 2.14 is the pumping process with and without gas ballast as it takes place in a rotary vane pump when pumping condensable vapors. 

Dixharge valve is pressed open, and particles of vapor and gas are pushed out -the overpressure required for this to occur is reached very early because of the supplementary gas ballast air, as at the beginning the entire pumping process condensation cannot occur... 

Fig. 2.14 Diagram of pumping process in a rotary vane pump without (teft) and with (right) gas battast device when pumping condensabie substances.

Pv2 Ps Pp2 relatively large gas ballast pump is required. Since the quantity of air involved during a pumping process that uses condensers is not necessarily constant but alternates within more or less wide limits, the considerations to be made are more difficult. Therefore, it is necessary that the pumping speed of the gas ballast pump effective at the condenser can be regulated within certain limits. 

The ultimate pressure attainable with adsorption pumps is determined in the first instance by those gases that prevail in the vessel at the beginning of the pumping process and are poorly or not at all adsorbed (e.g. neon or helium) at the zeolite surface. In atmospheric air, a few parts per million of these gases are present. Therefore, pressures < 10 mbar can be obtained. 

After a pumping process, the pump must be warmed only to room temperature for the adsorbed gases to be given off and the zeolite is regenerated for reuse. If air (or damp gas) containing a great deal of water vapor has been pumped, it is recommended to bake out the pump completely dry for a few hours at 200 °C or above. 

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