Materials Literature
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The inherent properties of diamond make it an ideal material for detectors in the high rate, high radiation environments near the collision point of future colliders such as the LHC. We have constructed charged particle position sensitive detectors using high quality chemical vapor deposited (CVD) diamond. Using detec…
The liquidus isotherms for the Ga–As–Bi system were determined at 973 and 923 K in the Ga–As–GaAs region. The liquid phase epitaxial growth of GaAs from Ga–As and Ga–As–Bi solutions were investigated. The addition of ten atomic percent of Bi to the Ga–As solution increase the growth rate of the grown epilayers nearly…
Challenges in the integration of ferroelectric nonvolatile memories with complementary metal-oxide-semiconductor (CMOS) technology for low-voltage and low-power applications are discussed. The main driving force for commercialization is to take advantage of the true high-speed (100 ns), low-voltage (0.9 V) write poten…
Abstract A novel method for the preparation of water‐soluble polypyrrole graft copolymers with polyamines or polyimines is described. The polyreaction is performed in acidic solution by using chemical oxidants, e.g. iron(III) chloride or ammonium peroxodisulfate. The graft copolymers showed electrical semiconductivity…
What can be done with radioactive waste? This extremely difficult question has not really been answered anywhere in the world; yet it must be answered. Like death and taxes, radioactive waste is with us—it cannot be wished away. This special, five-article issue of PHYSICS TODAY reviews the technical problems and risks…
We found aromatic copolymers comprising 4′-hydroxy 4-biphenyl carboxylic acid and 6-hydroxy 2-naphthoic acid with high second-harmonic-generation (SHG) activity. The polarization dependence of SHG in the solid film formed from the nematic phase reveals uniaxial and biaxial polar orderings.
A new theoretical method of evaluating polarizabilities of liquid crystals is presented and applied to the liquid crystalline compounds, namely n-alkyl-p-(4-ethoxy benzylidene amino)--methyl cinnamates, which exhibit smectic A and nematic phases. In the present method, vibrational frequencies are used to evaluate forc…
A synthesis of the d,l and meso forms of isochrysohermidin 3 is outlined which employs the singlet oxygen oxidation of pyrroles as the key step. The bipyrrole precursor 8 was synthesized from a 3-hydroxy monopyrrole which, in turn, was prepared by addition of methylamine to a vinyl vicinal tricarbonyl.
An analysis of Li‐intercalation and deintercalation in a tungsten‐oxide based electrochromic device is presented. An hysteresis between intercalation and deintercalation has been separately observed in both the built‐in potential and the optical efficiency of the devices. This hysteresis is explained by a two‐phase mo…
Recently, the innovative metallocene based catalyst technology has offered a new class of olefin polymers with molecular structures different from the traditional polyolefins produced with Ziegler-Natta catalysts. Metallocene polyolefins exhibit improved clarity, flexibility and impact resistance in comparison with co…
Abstract The glass transition temperatures of impact modified PVC with different amounts of lubricants have been used to define two new parameters of lubrication: the saturation concentration and the efficiency constant. The use of lubricants at significantly lower concentration than the saturation concentration ensur…
The sol−gel method was employed to prepare the precursor of zirconium oxide by the reaction of zirconyl chloride octahydrate (ZrOCl 2 ·8H 2 O and EDTA in ammonia. The reaction of ZrOCl 2 · 8H 2 O and the ionized complexing agent R(COO - ) n was achieved through sequential hydrolysis (4ZrOCl 2 ·8H 2 O + 20H 2 O → [Zr 4…
Parts I and II explain and evaluate a theoretical model that can predict the stress-strain and torque-strain curves of a yarn. Part III discusses the results of the experimental work on input parameters, that is, properties and arrangement of the fibers in the yarn. When appropriate values are taken for fiber and yarn…
Various strategies for the opening and filling of carbon nanotubes with encapsulated materials are described and discussed. Methods for the purification of the filled nanotubes are also presented.
The Ronchi grating is well known for its many applications in areas such as spectroscopy, grating interferometry, and Talbot interferometry. On the other hand, the checker grating has attracted very little attention. A checker grating also self-images at equidistant planes; the separation between these planes is a qua…
A new method for non-destructive quantitative analysis of surface nanostructures was developed in recent years. It relies on analysis of the XPS peak shape and usually the effects of elastic electron scattering are neglected in practical applications of the method. In the present paper we study the influence of elasti…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTSynthesis of Photodegradable Polymers Having Biodegradability and Their Biodegradations and PhotolysisYoichi Hiraguri and Yutaka TokiwaView Author Information National Institute of Bioscience & Human-Technology, 1-1, Higashi, Tuskuba, Ibaraki 305, Japan Cite this: Macromolecule…
The internal stress effect on the temperature dependence of the dielectric and lattice constant in a Sm-doped BaTiO 3 ceramic was investigated using various particle sizes of starting barium titanate, pressure-dielectric spectroscopy and a high pressure X-ray diffractometer. The grain size was nearly proportional to t…
A research program was conducted at the St. Anthony Falls Laboratory to investigate impulse pressures caused by the collapse of transient cavitation bubbles. The impulsive pressures associated with vibratory as well as hydrodynamic cavitation were measured. Both a stationary specimen subjected to vibratory cavitation…
The radical copolymerization of N-(2,6-dimethylphenyl)maleimide (DMPhMI) and 2,4,4-trimethylpentene (TP) was investigated in several solvents at 60°C. The copolymerization rate and the molecular weight of the resulting copolymers were dependent on the kind of solvent used. It was also revealed that the monomer reactiv…