Triplex

Quenching of the exciplex fluorescence by a third molecule may lead to a termolecular complex called triplex. It was first observed by Beens and Weller [47] and has since been shown to be a general phenomenon [48-53]. Each exciplex shows a marked preference for quenching by donor (DQ) or acceptor (Aq). The species approximately represented by Ds+. .. A8+ should be quenched from the D side by Dq, i.e., Dq+. .. D8+. .. A8-, or from the A side by Aq, i.e., Ds+. .. A8-... F Aq Caldwell s results showed a quenching preference when the interaction occurred with the exciplex component of lower singlet energy. Thus the exciplex of 9-cyanophenanthrene (9-(NP) and p-(isobutenyl) anisole (p-BA) clearly prefers Aq, while the exciplex of phenanthrene and FN prefers DQ. 

A triplex has been proposed as an intermediate in some photoreactions. Yang and co-workers [54] found that addition of 1,3-dienes to anthracene excimers leads to different products than does its adition to monomeric excited arenes. Lewis and co-workers [55, 56] found that stilbene excimers can be intercepted by dimethyl fumarate to give an oxetane through a presumed triplex. More recently, Schuster and co-workers [57,58] studied the Triplex Diels-Alder reaction of 1,3-dienes with enol, alkene, and acetylenic dienophiles. Take 9,10-dicyanonaphthalene (DCN)/indene (IN)/l,3-cyclohexadiene (CHD) system as an example  

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Under severe conditions and at high temperatures, noble metal films may fail by oxidation of the substrate base metal through pores in the film. Improved life may be achieved by first imposing a harder noble metal film, eg, rhodium or platinum—iridium, on the substrate metal. For maximum adhesion, the metal of the intermediate film should ahoy both with the substrate metal and the soft noble-metal lubricating film. This sometimes requires more than one intermediate layer. For example, silver does not ahoy to steel and tends to lack adhesion. A flash of hard nickel bonds weh to the steel but the nickel tends to oxidize and should be coated with rhodium before applying shver of 1—5 p.m thickness. This triplex film then provides better adhesion and gready increased corrosion protection. 

Decorative chromium plating, 0.2—0.5 ]lni deposit thickness, is widely used for automobile body parts, appHances, plumbing fixtures, and many other products. It is customarily appHed over a nonferrous base in the plating of steel plates. To obtain the necessary corrosion resistance, the nature of the undercoat and the porosity and stresses of the chromium are all carefliUy controlled. Thus microcracked, microporous, crack-free, or conventional chromium may be plated over duplex and triplex nickel undercoats. 

Duplex doiihle-acting compressor Triplex doiihle-acting compressor ... 

Triplex, three piston (not used as steam driven)... 

The single-action pump is usually available with three, five and even seven pistons. The odd number of pistons allows the pump to be rotationally balanced, and the use of at least three pistons reduces the discharge pulsation of these single-acting pumps. A three piston pump single-action pump is called a triplex pump. A five piston, or seven piston single-acting pump is called a multiplex pump. 

Figure 3-52. Simplex (double-acting), duplex (double-acting), triplex (single-acting), pressure-time curves [21].

Mud pumps consume more than 60% of all the horsepower used in rotary drilling. Mud pumps are used to circulate drilling fluid through the mud circulation system while drilling. A pump with two fluid cylinders, as shown in Figure 4-99, is called a duplex pump. A three-fluid-cylinder pump, as shown in Figure 4-100, is called a triplex pump. Duplex pumps are usually double action, and triplex pumps are usually single action. 

Figure 4-100. Triplex slush (mud) pump. (Courtesy National Oilwell.)...

The charts showing the p>erformance of duplex pumps are shown in Table 4-38 [17]. The charts showing the performance of triplex pumps are shown in Table 4-39 [17]. A chart listing the pump output required for a given annular velocity is shown in Table 4-40 [18]. A chart listing the power input horsepower required for a given pump working pressure is shown in Table 4-41 [19]. 

Note For single action triplex pump, multiply table value by 0.75. Note Values In the table are calculated tor a pump efficiency of 0.85. Courtesy International Association of Drilling Contractors. 

Theoretical output (gal/min) for a single action triplex pump is... 

The volumetric efficiency Ti for duplex pumps or triplex pumps is... 

Determine the appropriate circulation flowrate to be used for the diamond bit, turbine motor combination and the appropriate liner size to be used in the triplex pump. Also, prepare the turbine motor performance graph for the chosen circulation flowrate. Determine the total flow area for the diamond bit. 

Triplex Mud Pump, Model 10-P-13 National Supply Company, Example 2... 

Rahmel and Tobolsk have shown that the iron core below triplex scales of Fe0/Fe304/Fe203 grown in Oj + water vapour at 950°C become enriched in H, indicating that water vapour can penetrate relatively thick wustite scales. Cracks are a valid path for such diffusion but penetration can occur even when the oxide can deform plastically and there is no evidence of cracking. ... 

In rarer cases the ODNs also prevent normal gene transcription by directly forming triplex-helix structures with target DNA. This does not destroy a gene but prevents its unwinding or its binding to a gene promoter. 

Fig. 21.—Structure of the 6-fold anhydrous curdlan III (19) helix, (a) Stereo view of a full turn of the parallel triple helix. The three strands are distinguished by thin bonds, open bonds, and filled bonds, respectively. In addition to intrachain hydrogen bonds, the triplex shows a triad of 2-OH - 0-2 interchain hydrogen bonds around the helix axis (vertical line) at intervals of 2.94 A. (b) A c-axis projection of the unit cell contents illustrates how the 6-0H - 0-4 hydrogen bonds between triple helices stabilize the crystalline lattice.

Lyamichev, V., Frank-Kamenetskii, M., Soyfer, V. Protection against UV-induced pyrimidine dimerization in DNA by triplex formation. Nature, Vol.344, No. 6266, (1990), pp. 568-570, ISSN 1476-4687... 

Splice bars divided into two parts for triplex three parts for quadroplex... 

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