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Several samples of pyramids from Giza were obtained. The samples were analysed by scanning electron microscopy, electron diffraction by X-rays, powder X-ray diffraction, inductively coupled plasmography, Fourier-transform infrared spectroscopy and other techniques. Some scientists who have recently studied the pyramids have suggested that the pyramids were poured into place, stone by stone. The prevailing theory among Egyptologists is, of course, that the pyramids were built from blocks of natural stone. All of the results obtained during this study directly support the concept that the pyramids are made of limestone and are not cementitious in nature.

The formation and growth of intermetallics at the solder/substrate interface are factors affecting the solderability and reliability of electronic solder joints. This study was performed to better understand the diffusion behavior and microstructural evolution of Cu−Sn intermetallics at the composite solder/copper substrate interface for eutectic solder and solder alloys containing particle additions of Cu, Cu3Sn, Cu6Sn5, Ag, Au, and Ni. Annealing temperatures of 110 to 160°C were used with aging times of 0 to 64 days. The copper-containing composite solders generally formed thinner Cu6Sn5 layers, but thicker Cu3Sn layers than were formed by the eutectic solder alone. These copper-containing additions, therefore, resulted in increased activation energies for Cu6Sn5 formation and decreased activation energies for Cu3Sn formation as compared to the eutectic solder. The activation energy for Cu3Sn formation decreased relative to eutectic solder for silver and gold composite solders even though less Cu3Sn was formed at the substrate interface. Nickel and palladium drastically reduced the Cu3Sn thickness and increased the Cu6Sn5 thickness. However, the Cu6Sn5 contained a substantial volume fraction of voids close to the copper substrate. We propose two mechanisms to explain the effects of the copper-containing and silver particles on the kinetics of intermetallic formation. First, the particles act as tin-sinks which remove tin from the solder and decrease the amount of tin available for reaction at the solder/substrate interface. Second, the particles reduce the cross-sectional area available for tin diffusion, which also reduces the amount of tin available at the interface for reaction.

A combination of analytical methods was used on printed circuit board coupons to conclude the following: (1) while steam ageing deteriorates solderability of tinned coupons, it does not increase the oxide thickness or tin‐lead ratio of the surface (top 50 Angstroms) of tinned coupons; (2) therefore, some other factor, probably oxidation of the copper or tin/copper intermetallic substrate, determines solderability of the coupons.

(2002). An Easy Field Test for Distinguishing Sodium from Potassium Water-Soluble Minerals. Rocks & Minerals: Vol. 77, No. 6, pp. 414-415.

SEM/EDX is a powerful way to characterize solder in resolving solderability and reliability problems. SEM/EDX is a combination tool, with two instruments working in partnership. These two instruments operate simultaneously to complement each other’s data acquisition, guided by the instrumental operator. Scanning electron microscopy (SEM) provides an image (i.e., morphological information or surface features) on a magnified scale—X10 to X100,000, although the usual range is perhaps X50 to X5000.1 Energy dispersive x-ray (EDX) determines the elemental composition of an area, with a sensitivity of perhaps 0.1 to 1 percent composition and with a spatial resolution of 1 µm.2 EDX is commonly used for elements with atomic number ≥11 (sodium), but thin window EDX systems can also detect elements with atomic number ≥5 (boron). With these two instruments operating together, the instrumentalist can scan areas of potential interest, zoom in with higher magnification, and determine elemental compositions in selected areas of interest.

This paper gives a detailed description, including GPS coordinates, of the location of the Ytterby Mine, Resaro Island, Sweden. This mine is famous for its mineralogical treasures and was the derivation of the names yttrium, ytterbium, terbium, and erbium. A number of streets on the island are named after elements and minerals. A nearby museum contains a small exhibit on the mine. A sample of Ytterby gadolinite from this mine (the mineral from which yttrium was discovered) was analyzed and found to contain high concentrations of certain rare earths.

The cover of the August 2000 issue featured mineral samples associated with elements on the left side of the periodic table. Readers may be interested in the following information about the mineral...

All J CH values, including signs, involving the carboxyl carbon of crotonic and isocrotonic acids have been derived from a proton NMR study involving spintickling of the >90%- 13 C-carboxyl-labeled derivatives. These long-range J CH values, along with J CH values previously obtained from the benzoate and acrylic systems, correlate well with the J HH values of geometrically equivalent proton-proton systems (except for the geminal couplings), attesting to similar coupling mechanisms in carbon-proton and proton-proton systems for 3-, 4-, and 5-bonded couplings.

9-13C-Anthrone (1), -9-methylanthracene (2), and -9-methoxyanthracene (3) enriched to more than 90% have been synthesized and carbon-carbon coupling constants involving the labeled-9-carbon have been determined. It is shown that these long-range carbon-carbon couplings can be used to make correct chemical shift assignments. These assignments are verified by a study of homologous compounds and of proton-coupled spectra. These long-range carbon-carbon coupling constants, along with previously obtained couplings from toluene and benzoic acid, find good correlation with the π-bond order of the respective coupling paths. A surprisingly large 4Jcc is noted for 2 and 3.

Fluorene-9-13C, fluorenone-9-13C, acenaphthenone-11-13C, acenaphthenone-12-13C, 1-methylcyclopentanol-1-13C and 1-methylcyclopentene-1-13C were synthesized to obtain J(CC) values between the natural carbons and the labeled carbons. Each of these compounds possessed at least one asymmetric dual-path coupling, i.e., coupling between the labeled carbon and another carbon via simultaneous two- and three-bonded coupling paths. Model 13C-labeled compounds were synthesized where necessary to give expected values of the constituent mono-path couplings. Values of these dual-path couplings (2+3)J suggested that the observed value is the (at least approximate) algebraic sum of the two constituent J values.

In a series of norbornanes, benzonorbornenes, and norbornenes, the vicinal cis couplings 3Jexo,exo and 3Jendo,endo are determined. A trend is recognized in which Jexo,exo steadily decreases in this series while Jendo,endo remains relatively constant; in norbornenes Jexo,exo and Jendo,endo are about the same. These observations are understood by means of theoretical calculations performed for representative compounds of the series. This study indicates that interactions of the C7-methylene bridge with the bonds of the C2C3 ethylene bridge are responsible for the nonequivalence of Jexo,exo and Jendo,endo in norbornanes, and that in norbornenes interaction of the olefin functionality with bonds of the ethylene bridge is responsible for bridging Jexo,exo back fortuitously close to Jendo,endo.

A series of (>90% isotopic purity) 13C-labeled aliphatic alcohols of the general structure CCC13COH were synthesized and studied by 13C n.m.r. to obtain all 13C13C couplings involving the labeled carbon. The 2J(CC) values were small (

A new, efficient route was used in the synthesis of [2,2]paracyclophane-2-carboxylic acid. The chiral acid was then resolved and the Birch reduction performed yielding one enantiomer of tetrahydro[2,2]paracyclophane-2-carboxylic acid. The UV spectrum of tetrahydro[2,2]paracyclophane-2-carboxylic acid in isopentane shows one absorption at 206 nm (ϵ max =5271). There are three bands observed in the CD spectrum in isopentane at 236 nm ([θ] = 1.8 × 10 4 ), 201 nm ([θ]=-16×10 4 ) and a positive band indicated below 180 nm but not observed, in ethanol the CD spectrum exhibits a band at 205 nm ([θ]= 1.5×10 4 ) and the UV spectrum shows a band at 208 nm (ϵ max =5915). The bands were assigned and possible reasons for the occurrence of a π→π * transition at unexpectedly long wavelengths are discussed.

A tabulation has been compiled for twenty 13CH coupling constants of various carboxylic acids and includes 2J(C,H), 3J(C,H) and 4J(C,H) values of olefins (both cis and trans); 3J(C,H), 4J(C,H) and 5J(C,H) values of aromatics; 3J(C,H) and 4J(C,H) values of acetylenes; and 2J(C,H) and 3J(C,H) values of rigid aliphatics. This tabulation has been completed in the present study by the spin-tickling proton n.m.r. study of 13C-carboxyl-endo-1,2,3,4,7,7-hexachloronorbornene-5-carboxylic acid, which has established that the 2J(C,H) value is negative and the 3J(C,H) values (both cis and trans) are positive in this system. A plot of these twenty J(C,H) values vs the corresponding J(H,H) values of geometrically equivalent model systems (where there is a proton in place of a carboxyl group) gives a correlation coefficient of 0·975 (with a slope of 0·62), indicating that carbon–proton and proton–proton couplings operate by similar mechanisms throughout this broad series of structural types.

A series of 7-13C-labeled o-substituted toluene derivatives and carboxyl-13C-isocrotonic and crotonic acid were synthesized and studied by 13C NMR spectroscopy to obtain 13C13C spin-spin coupling constants involving the labeled carbon. The cis3J(CC) values were different from those in previous studies in that these J(CC) values were relatively small and the usual dependence of 3J(CC) on the s-character of the terminal carbon was reversed. Further, a strong dependence of 3J(CC) on the conformational orientation of a terminal carbonyl group was shown to exist. Through-space interactions of the two coupling carbons were shown to contribute to these ‘anomalous’ results, and thus it was shown the cis carbon-carbon couplings may not be directly related to geometrically equivalent proton-proton couplings, as are other carbon-carbon couplings.