Definition periodic

The strength of the ion current relates to the number of ions per second arriving at the collector plate, and a mass spectrum can be regarded as a snapshot of the current taken over a definite period of time. Because of the finite time taken to produce a mass spectrum, it is a record of the abundances of ions (often mistakenly called intensities of ions). 

Pulse A type of input in which the concentration of tracer in the input stream is changed suddenly, maintained at a non-zero value for a definite period, then changed to the original value and maintained that way for the period of interest. When the pulse is of constant magnitude it is called a square pulse. 

The simplest and the most common method of separating mixtures exclusively by size alone is to make a screen analysis using testing sieves. A set of standard screens is arranged serially in a stack, with the smallest mesh at the bottom and the largest at the top. The analysis is carried out by placing the sample on the top screen. The stack is agitated manually or mechanically for a definite period. The particles retained on each screen are removed... 

As the field has a definite periodic behavior with frequency co, we shall also assume that ... 

Very low concentrations of substrates may be assayed by recycling the test substrate for an appreciable but definite period of time and measuring the amount of product formed. The coenzyme NADPH, for instance, may be assayed using the two enzymes glutamate dehydrogenase (EC 1.4.1.3) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) ... 

The volumetric flow rate is measured either by cumulative devices which collect the bubbles for a definite period of time or by rate measuring devices. 

The very idea of an intermolecular chemical bond, in conjunction with crystal periodicity, leads to the concept of chain formation. One is never too careful, however, because crystal structures are by definition periodic in space and, vice versa, the concept of chain can surreptitiously sneak in without the need of a real chemical bond. Once again, there is a dichotomy between geometrical appearance -a ribbon of molecules close to each other - and objective physics, or the presence of an effective electronic interaction between the partners in the supposed periodic structure. The basic question is, how and when is one allowed to trace a chemical bond, and thus legitimately to draw a chain structure The answer - or at least what in this author s opinion is the only objective and physically sound answer - must come from quantitative evaluation of the involved contact energies, as discussed in the next paragraphs. 

Annealing A heat treatment process directed at improving performance by removing stresses in the material formed during its fabrication. Typically, the part, sheet, or film is brought to a specific temperature for a definite period of time, and then cooled down slowly to ambient temperature. 

Berkhout Stability Test, designed in the artillery laboratory at Hembrug,Holland, consists in heating samples of NC or propints in weighing bottles at 95°, 105° or 110° and noting the loss of wt in a definite period(such as 72 hrs), as well as the time required for evoln of red fumes. The heating is conducted in a specially designed thermostatically controlled oven. Two models of such ovens are described in Ref 1 (Compare with Jacque Test and with Sy Test) Refs 1)J.D.Berkhout,SS 17,33 4(1922) CA 16, 2602(1922) 2)Reilly(1938),85... 

The layers may be regularly or randomly interstratified. The latter are by far the more common and are probably the second most abundant clay mineral species, following illite (which in most cases is a mixed-layer clay). More regularly interstratified clay minerals have a definite periodicity and some are given specific mineral names. The randomly interstratified clay minerals are described in terms of the type and proportion of the two or more types of layers. Many of them exhibit some degree of regular interlayering. 

A type of processing equipment in which the entire amount of material to be used is put into the mixer and mixed for a definite period, with multiple recirculation of material through the mixing zone, in contrast to what happens in a continuous mixer. After the mixing period the whole amount of material is removed from the mixer. In oil production or processing, the process in which emulsion is collected in a tank and then broken in a batch. This process is used as opposed to continuous or flow-line treating of emulsions. 

If adsorption is a necessary prerequisite for electron transfer, one would intuitively expect that this would lead to a substrate-electrode complex of defined structure (e.g., an aromatic ring system would be held with its planar surface facing the electrode surface). The exact chemical consequences of this arrangement are hard to predict, but at least one implication would be one of stereochemistry. If the configuration ad sorbant-surface is held for a definite period of time after electron transfer has taken place, any following fast product-forming steps would occur with the intermediate shielded from chemical attack on one side by the electrode, and therefore the stereochemistry of the reaction should be affected. 

When an atom makes a transition from a high-energy quantum state to a lower energy state, electromagnetic radiation with a definite frequency and a definite period is emitted. When properly detected, this frequency, or period, becomes the ticking of an atomic clock, just as the crystal vibration frequency and the swinging frequency are the inaudible ticks of a quartz clock and a pendulum clock. The frequency emanating from the atom, however, is much less influenced by environmental factors such as temperature, pressure, humidity, and acceleration than are the frequencies from quartz crystals or pendula. Thus, atomic clocks hold inherently the potential for reproducibility, stability, and accuracy. 

For the purpose of examining the size of editions—i.e., the number of printed copies as it varies with the character of the publication and over a period of time-100 titles currently received in this country were selected. These publications comprise predominantly periodicals—i.e., publications scheduled to appear at definite time intervals—and a few serials or publications appearing continuously but having no definite periodicity. 

Many fireworks (set pieces) can only be successful and produce the desired effect if some parts, such as torches, squibs, otc., have a definite time for burning. Time fuses are used for exploding charges, or for igniting fireworks in a definite period of time. These time fiises are tubes fitted with a mixture in such a manner that a certain length will bum in a definite time. 

If we allow the process of dissolution to continue without setting up any artificial currents to aid diffusion this concentrated film in direct contact with the solid is going to become thicker and thicker and the speed of dissolution is going to become slower and slower as the thickness increases. This is not due to the effect of mass action alone but also because it takes a definite period of time for the dissolved particles to... 

This regularity refers to the length interval of the parameter values at which periodic motion with some definite period is stable. These intervals are reduced at each reduplication of the period, the multiplier characterizing the reduction approaching the universal value ... 

Controlled release implies regulation of the delivery of a drug usually by a device. The control is aimed at delivering the drug at a specific rate for a definite period of time independent of the local environments. The periods of delivery are usually much longer than in case of SR and vary from days to years. Controlled release may also incorporate methods to promote localization of drug at an active site. Site-specific and targeted delivery systems are the descriptive terms used to denote this type of control. 

The contribution of individual groups of trajectories to the air transport to the studied region in a definite period of time was estimated from the relative number of the trajeetories of this group, and by dividing the air masses into types. 

Murphy et al. (163) studied the DTA. of Vibrin 135 resins, the results of which are shown in Figure 7.50. Three samples of resin were studied two of them contained 2%. ferf-butylperbenzoate catalyst, the other 0.5%. Each catalyst-resin mixture was then heated (cured) for a definite period of time. The DTA. curves in (1) and (2) showed that two low-temperature exothermic peaks were observed, with ATmax values of 150 and l80°C, respectively. This first peak was missing from the post-baked (180°C for 24 hours) sample, although the 320°C peak was found in all three curves. The presence... 

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