Materials Literature
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Abstract Dynamic mechanical behavior during the reactions of four aromatic diamines ( m ‐phenylenediamine, 4,4′‐diaminodiphenylmethane, 4,4′‐diaminodiphenyl sulfone, and benzidine) with the diglycidyl ether of bisphenol A was studied by torsional braid analysis under isothermal conditions. Depending on the cure temper…
Abstract Alkaline hydrolysis of model carbamates, polyurethanes, and poly(urethane‐ureas) has been investigated. The model carbamates were based upon phenyl, benzyl, and cyclohexyl isocyanates. The polyurethanes and poly(urethane‐ureas) were prepared from tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), and 4…
Single crystals of NaCl, NaBr, KCl, and KBr containing divalent additions of Ca 2+ , Sr 2+ , and Ba 2+ were tested mechanically. In the solution‐treated condition, the yield strength, σ v , as determined from compression testing in a 〈100〉 direction is essentially dependent on the concentration of the dopant only and…
The complications of calculating the photoabsorption cross section of atoms for frequencies in the far ultraviolet and soft x-ray regions motivate an analysis of this problem on the basis of the Bloch semiclassical model of hydrodynamic charge oscillation in the neutral Thomas-Fermi atom. The hydrodynamic modes of osc…
Abstract Although hair form has received much attention in the past, it has rarely been studied systematically, and never using direct curling variables. In the present study, seven groups were scored on eight variables, including four newly‐devised curling variables. These data were analyzed using univariate and mult…
Most sulfosalts may be regarded as intermediate phases on joins between simple sulfide components (e.g., all lead sulfbismuthinides lie on the PbS-Bi2Sa join). Many of the structures are characterized by subunits whose individual structures are similar to those of the component simple sulfides (e.g., galena-like and s…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTheory of Copolymer CrystallizationEugene Helfand and John I. Lauritzen Jr.Cite this: Macromolecules 1973, 6, 4, 631–638Publication Date (Print):July 1, 1973Publication History Published online1 May 2002Published inissue 1 July 1973https://pubs.acs.org/doi/10.1021/ma60034a03…
Water circulation affects the sedimentation of pollen grains in lakes, sorting them according to morphological type. Pollen grains with rapid rates of sinking fall downward through the water and are deposited evenly onto the sediment throughout the lake. Those with slower sinking speeds in water, due to small size or…
The Yafet-Kittel angles of the disordered system ${\mathrm{Zn}}_{x}{\mathrm{Ni}}_{1\ensuremath{-}x}{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$ for $0\ensuremath{\le}x\ensuremath{\le}1$ have been determined using ${\mathrm{Fe}}^{57}$ M\"ossbauer spectroscopy with and without an external magnetic field. It is found that for $x\e…
Infrared and ultraviolet absorption spectra arising from f→f and f→d transitions of Ce3+ in YAlO3 crystals are presented and used to derive the 4f and 5d energy levels. Excitation and fluorescence spectra of 5d→4f emission are also reported. The 5d fluorescence has a decay time of 16 nsec and a radiative quantum effic…
The surface structures and interior dislocation structures of fatigued copper and copper-5 at. % aluminium crystals have been studied using replicas and scanning and transmission electron microscopy techniques. A very regular structure of walls of dislocations has been found; these walls consist of primary edge dipole…
Optical absorption and emission intensities are investigated for trivalent rare earths in YAl${\mathrm{O}}_{3}$. Ions examined included Pr, Nd, Eu, Tb, Ho, Er, Tm, and Yb. Oscillation strengths of $f\ensuremath{\rightarrow}f$ transitions between $J$ manifolds were measured at room temperature and compared with calcula…
A survey, comparison, and critical analysis is presented of data compiled from the scientific literature concerning copper self-diffusion. Topics include volume diffusion, dislocation pipe diffusion, surface diffusion, sintering, electromigration, thermomigration, pressure effect on diffusion, strain-enhanced diffusio…
Nonradiative relaxation by multiple-phonon emission was investigated for excited electronic states of rare-earth ions in YAl${\mathrm{O}}_{3}$. Ions studied included ${\mathrm{Nd}}^{3+}$, ${\mathrm{Eu}}^{3+}$, ${\mathrm{Ho}}^{3+}$, ${\mathrm{Er}}^{3+}$, and ${\mathrm{Tm}}^{3+}$. Rates of multiphonon emission were dete…
A new method for obtaining permanent quantitative slides of microfossils involves the use of an evaporation tray in which microfossil suspensions can be sedimented randomly onto cover slips on the tray floor. Slides are made after evaporation. The technique is statistically reliable.
A comprehensive compilation is given of elastic properties of iron-nickel alloys. When sufficient data exist, preferred values are recommended. This compilation covers, besides pure iron and pure nickel, the entire binary composition range, both b.c.c. and f.c.c. phases. Elastic constants included are: Young's modulus…
TABLE OF CONTENTS 1. Introduction 728 2. Crystal Structure 728 3. Optical Properties and Band Structure 732 4. Electrical and Galvanomagnetic Properties 734 5. Antifriction Properties 738 6. Conclusions 739 Bibliography 740
Results are presented of an investigation on the origin of the low temperature coefficient of resistance in NiCr thin films. It is shown that this low temperature coefficient is an intrinsic property of the alloy. Besides NiCr a large number of disordered alloys containing transition metals have similar conduction pro…
Raman spectra of polycrystalline films of CHCl3 and CDCl3 have been recorded at 77°K. Splittings due to the four chlorine siotropic molecules have been resolved for the ν3(A1) bands of both CHCl3 and CDCl3. After taking isotopic effects into account, further splittings of the fundamentals in the Raman spectra together…
Vibrational frequencies of the NO3− ion in matrix-isolated monomers of several nitrates MNO3 are shown to correlate with the polarizing power of the cation M+, P≡ (z/r)/Seff, properly defined as the quotient, rather than the product, of the ionic potential, z/r, and a factor Seff= (5z1.27)/(r(1/2)I) (Ahrens, 1954) rep…