With Pb

Modem NDT film systems (with Pb screens) are very linear X-ray detectors. This is shown in fig.l for different NDT film systems and a X-ray tube at 160 kV. Note that for histoncal reasons the film response curve is often plotted as film density versus log (radiation dose), which hides this linear relationship. The film density is the difference between the measured optical film density and the fog density Db of the film base. 

Oxidation of a glycol can lead to a variety of products. Periodic acid quantitatively cleaves 1,2-glycols to aldehydes and is used as an analysis method for glycols (12,13). The oxidation of propylene glycol over Pd/C modified with Pb, Bi, or Te forms a mixture of lactic acid, hydroxyacetone, and pymvic acid (14). Air oxidation of propylene glycol using an electrolytic crystalline silver catalyst yields pymvic aldehyde. 

An estimate of world calcium consumption in 1986 indicated that lead refining uses 30% alloys, eg, with Pb, Al, and Si, 25% steel treatment, 20% calciothermic reduction, 10% calcium hydride, 10% and miscellaneous usage is 5%. More recent evidence, however, has suggested that increasing consumption of calcium in battery manufacture has made this the most significant use. 

Certain perovskites with Pb on the A site are particularly important and show pronounced piezoelectric characteristics (PbTiO, PZT, PLZT). Different responses are found in BaTiO and PZT to the addition of donor dopants such as La ". In PZT, lead monoxide [1317-36-8] PbO, lost by volatilization during sintering, can be replaced in the crystal by La202, where the excess positive charge of the La " is balanced by lead vacancies, leading to... 

Oxidation of the hydrazone of 2-hydrazinopyrazole (226) with Pb(OAc)4 in CH2CI2 is a two-step reaction. The azine (227) was formed as an intermediate and this underwent ring closure to the 3H-pyrazolo[5,l-c][l,2,4]triazole (228) (79TL1567). A similar reaction applied to the benzal derivative of 2-hydrazinobenzothiazole (229) gave 3-phenyl-[l,2,4]triazolo[3,4-6]benzothiazole (230) together with a by-product (231) (72JCS(P1)1519). 

The phenylene group is removed oxidatively with Pb(OAc)4 in dioxane. 4-Triphenylmethylaminophenyl 4-[(C6H5)3CNH]C6H4-Formation... 

The main use of elemental As is in alloys with Pb and to a lesser extent Cu. Addition of small concentrations of As improves die properties of Pb/Sb for storage batteries (see below ), up to 0.75% improves the hardness and castabilily of type metal, and 0 5-2.0% improves the sphericity of Pb ammunition. Automotive body solder is Pb (92%),, Sb (5 0%), Sn (2.5%) and As (0.5%). Intcrnxitallic compounds with Al, Ga and In give the 111-V semiconductors (p 255) of which GaAs and InAs are of particular value for light-emitting diodes (LEDs), tunnel diodes, infrared emitters, laser windows and Hall-effect devices (p. 258). 

Bismuth oeeurs mainly as bismite (a-Bi203), bismuthinite (Bi2S3) and bismutite [(Bi0)2C03] very oeeasionally it oeeurs native, in assoeiation with Pb, Ag or Co ores. The main eommereial souree of the element is as a byproduet from Pb/Zn and Cu plants, from whieh it is obtained by special processes dependent on the nature of the main product. Sulfide ores are roasted to the oxide and then reduced by iron or charcoal. Because of its low mp, very low solubiUty in Fe, and fairly high oxidative stability in air, Bi can be melted and cast (like Pb) in iron and steel vessels. Like Sb, the metal is too brittle to roll, draw, or extrude at room temperature, but above 225°C Bi can be worked quite well. 

Recent experience with Pb-6Sb-lAg and Pb/Pt anodes operating in seawater at depths greater than 25 m has revealed a marked increase in consumption rate compared with that found on the surface. Hollandsworth and Littauer" have calculated that on a fully formed anode at 400 Am only 6 X 10 % of the current is used to maintain the passive film, yet at a depth of 180m this percentage increases to 2 x 10 %, and results in a 30-fold increase in consumption rate. They propose that a combination of... 

It was first prepd in low yield by the action of Cl trifluoride on bromodifluoronitroso me thane and by the oxidn of trifluoronitrosomethane with Pb dioxide (Ref 2). The Pb dioxide oxidn of the nitroso compd was repeated by Hazeldine who obtd a 37% yield (Ref 3). This oxidn has also been carried out using dimanganese hcptox-ide (Ref 3), 30% hydrogen peroxide in a sealed tube (Ref 4) and activated C (apparently contg adsorbed 02) in a sealed tube at 150° for 1... 

Woodring, USP 2206652 (1940) CA 34,7610 (1940) [Primer compn contg Pb, Na or Cd salts of trinitrophloroglucinol with Pb Styphnate and other ingredients] 10) R- Schmitt, SS 38, 149 (1943) [Quant estimation of trinitrophloro-glucinol by pptn with phenyl ad ridine soln]... 

It forms salts, some of which are expl, eg Basic Lead Salt. PbCgHjOgN, mw 416.32, N 3.36%. Was proposed by Briin for use in mixts with Pb Styphnate, Pb nitrate, etc, in expl compns (Ref 3)... 

Lead Picrate. [CeHiCNOa O] 2Pb, mw 663.41 N 12.67% yel crysts mp, explds violently at 270-81°. Can be obtained by heating either the monohydrate or tetrahydrate to 150°. The tetrahydrate is obtained in the form of silky yel needles when an aq soln of PA is treated with Pb carbonate. The Ger method of prepn is given under Bleipikrat in Ref 9... 

Prepd by treating methoxy picric acid with Pb hydroxide. It loses its OCH3 group thru hydrolysis to form normal Pb Styphnate. The OPbOH group displays acidic behavior in soln. 

Plomoplastrita (Span). An expl obtained by mixing Plastrita (qv) with Pb nitrate. It is as powerful as TNT, possesses a higher d, is less sensitive to mechanical action, and does not evolve poisonous gases on expln Ref Sancho (1941), 153... 

Pulverin. French for meal powder. A special, finely pulverized BlkPdr consisting of K nitrate 75, S 12.5 and charcoal 12.5%, prepd by rolling the ingredients with Pb or lignum vitae balls in a hardwood barrel. It has been used in pyrotechnic applications... 

Asymmetric oxidation of this sulphide was also catalyzed by two isocytochromes P 450 purified from phenobarbital induced rat liver309. Both P 450 isocytochromes, termed PB-1 and PB-4, when reconstituted with purified rat liver NADPH-cytochrome P 450 reductase and cytochrome b5 afforded ethyl p-tolyl sulphoxide with S-configuration at the sulphur atom. In the case of PB-1 optical purity of this sulphoxide was 58% whereas with PB-4 it was 78%. 

Transient absorption spectra were measured with PBS in dioxane solution. In aerated solution the absorption decayed by two processes, a rapid one with f 1/2 50 /rs and a slow one with fj/2 20ms. In argon-saturated solution, a relatively weak absorption which decayed with f1/2 20ms was observed. The rate of the rapid decrease in the optical density agrees with that of the decrease in the intensity of the scattered light. 

As no long-lasting absorption was detected with pure dioxane, the transient absorptions found with PBS solutions are due to macroradicals or macroions. 

The first studies of the electrical double-layer structure at Sn + Pb and Sn + Cd solid drop electrodes in aqueous surface-inactive electrolyte solutions were carried out by Kukk and Piittsepp.808 Alloys with various contents of Pb (from 0.2 to 98%) were investigated by impedance.615,643,667,816 Small amounts of Pb caused dramatic shifts of toward more negative values. For alloys with Pb bulk content 0.2%, was the same as for pc-Pb. The was independent of Crf and frequency. C xt Cjl plots were linear, with/pz very close to unity. Thus the surface of Sn + Pb alloys behaves as if it were geometrically smooth, and Pb appears to be the surface-active component. 

X-ray scattering studies at a renewed pc-Ag/electrolyte interface366,823 provide evidence for assuming that fast relaxation and diffu-sional processes are probable at a renewed Sn + Pb alloy surface. Investigations by secondary-ion mass spectroscopy (SIMS) of the Pb concentration profile in a thin Sn + Pb alloy surface layer show that the concentration penetration depth in the solid phase is on the order of 0.2 pm, which leads to an estimate of a surface diffusion coefficient for Pb atoms in the Sn + Pb alloy surface layer on the order of 10"13 to lCT12 cm2 s i 820 ( p,emicai analysis by electron spectroscopy for chemical analysis (ESCA) and Auger ofjust-renewed Sn + Pb alloy surfaces in a vacuum confirms that enrichment with Pb of the surface layer is probable.810... 

The mechanism of glycol oxidation with Pb(OAc)4 was proposed by Criegee ... 

C = C—NO2 —> — CH—C=NOH) with sodium hypophosphite and with Pb—HOAc—DMF, as well as with certain other reagents. ... 

Radioactive decay provides splendid examples of first-order sequences of this type. The naturally occurring sequence beginning with and ending with ° Pb has 14 consecutive reactions that generate a or /I particles as by-products. The half-lives in Table 2.1—and the corresponding first-order rate constants, see Equation (1.27)—differ by 21 orders of magnitude. 

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