Materials Literature
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The plasma‐enhanced chemical vapor deposition process for SiN x H y films has been in use for over two decades, but the chemistry of the process has yet to be explained. In the present work, the composition of a 13 MHz NH 3 ‐ SiH 4 parallel plate glow discharge plasma was analyzed by line‐of‐sight sampling from the fi…
Filamentous phage infection induces the synthesis of large amounts of an Escherichia coli protein, phage shock protein (Psp), the product of a previously undescribed gene. This induction is due to the phage gene IV protein, pIV, an integral membrane protein. The uninduced level of Psp is undetectable, but when induced…
Historically, multilayer ceramic capacitors (MLC's) have not been considered for energy storage applications for two primary reasons. First, physically large ceramic capacitors were very expensive and, second, total energy density obtainable was not nearly so high as in electrolytic capacitor types. More recently, the…
Effects of alloying elements on the corrosion resistance of mostly binary rapidly solidified (RS) magnesium alloys were examined using electrochemical techniques. Uniform corrosion rates were measured at room temperature in a p H 9.2 sodium borate buffer using electrochemical impedance spectroscopy (EIS). Comparisons…
From transmission electron microscopy studies on several complex lead perovskite compounds Pb(B'B'')O 3 , and their solid solutions a classification can be obtained based on B-cation order. This classification divides the complex lead perovskites into three subgroups; random occupation or disordered, nanoscale or shor…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and characterization of surface-capped, size-quantized cadmium sulfide clusters. Chemical control of cluster sizeNorman Herron, Ying Wang, and Hellmut EckertCite this: J. Am. Chem. Soc. 1990, 112, 4, 1322–1326Publication Date (Print):February 1, 1990Publication His…
In polycrystalline semiconductors the trapping of charge at the grain boundaries has a decisive influence on the electrical transport properties through the formation of electrostatic potential barriers. By proper materials processing many interesting device applications can be realised, which exploit the electrical a…
Three‐dimensional structures in silicon are increasingly coming into use for the fabrication of mechanical and electrical devices. The fabrication of deep trenches is one of the most important problems in VLSI (very large scale integration) technology. In this study the spontaneous trench formation in n‐type silicon i…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNucleation and Growth of CdSe on ZnS Quantum Crystallite Seeds, and Vice Versa, in Inverse Micelle MediaA. R. Kortan, R. Hull, R. L. Opila, M. G. Bawendi, M. L. Steigerwald, P. J. Carroll, and Louis E. BrusCite this: J. Am. Chem. Soc. 1990, 112, 4, 1327–1332Publication Date…
An ac technique for measuring the thermal conductivity of dielectric solids between 30 and 750 K is described. This technique, the 3ω method, can be applied to bulk amorphous solids and crystals as well as amorphous films tens of microns thick. Errors from black-body radiation are calculated to be less than 2% even at…
Abstract Starburst dendrimers are three‐dimensional, highly ordered oligomeric and polymeric compounds formed by reiterative reaction sequences starting from smaller molecules—“initiator cores” such as ammonia or pentaerythritol. Protecting group strategies are crucial in these syntheses, which proceed via discrete “A…
The temperature dependences of the coefficients representing preferential grain-boundary diffusion (PGBD), the dependences of the PGBD parameters on excess charges of atomic probes, and the isotopic effect under the PGBD conditions made it possible to identify the interstitial PGBD mechanism for a number of f.c.c. met…
Abstract CH‐type catalysts were prepared by reacting MgCl 2 · ROH, where ROH is 2‐ethyl hexanol (EH), (R)‐2‐octanol (R‐20), and (S)‐2‐octanol (S‐20), with TiCl 4 in the presence of di‐ i ‐butyl phthalate (BP), di‐ i ‐butyl terephthalate (BT), (‐)‐dimenthyl phthalate (MP), or (‐)‐dimenthyl terephthalate (MT). The MT ca…
Abstract A series of new polyimides containing fluorinated alkoxy side chains are prepared from novel fluorinated alkoxy diamines. The dieletric constant at 1 kHz in the fluorinated polyimides decreases from 3.3 to 2.6 as fluorine content increases. The refractive index also changes from 1.58 to 1.48, dependent on the…
We have determined and refined the X-ray crystal structures of six periplasmic binding proteins that serve as initial receptors for the osmotic-shock sensitive, active transport of L-arabinose, D-galactose/D-glucose, maltose, sulphate, leucine/isoleucine/valine and leucine. The tertiary structures and atomic interacti…
It is shown that Frank's ``saddle'' distortion contribution to the nematic liquid-crystal distortional elastic energy is required, in addition to the splay, twist, and bend energies retained in more recent treatments. ``Normal distortion modes'' for these four distortions are described. Measurement methods and their i…
For the first time the observation of a sharp peak in the broad luminescence spectrum of hydrogenated amorphous silicon (a-Si:H) has been achieved, using erbium as a dopant. Thus, a method of investigating the structure of solid-state systems which previously has only been used with crystals can now be applied to a-Si…
Thin diamond films were deposited on different substrates at temperatures below 500 °C by a microwave plasma-enhanced chemical vapor deposition system. The deposited films were amorphous carbon or diamond films depending on the different gas mixtures used. The addition of oxygen to the gas mixtures was found to be cri…
Single crystals of the new nonlinear optical material 3-methyl-4-methoxy-4′-nitrostilbene (MMONS) have been grown by a seeded solution growth technique and the linear and nonlinear optic and electro-optic properties determined. MMONS is highly birefringent with nz−nx =0.75 (0.532 μm), has large nonlinear optical coeff…
A detailed comparison between molecular dynamics computer simulations and the experimental characterization of molecular motion through deuterium nuclear magnetic resonance (NMR) spectroscopic methods has been carried out for the crystalline phase of nylon 66 (polyhexamethyleneadipamide) at room temperature and just b…