Materials Literature
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Low optical bandgap conjugated polymers may improve the efficiency of organic photovoltaic devices by increasing the absorption in the visible and near infrared region of the solar spectrum. Here we demonstrate that condensation polymerization of 2,5-bis(5-trimethylstannyl-2-thienyl)-N-dodecylpyrrole and 4,7-dibromo-2…
Electrical conductivity measurements in the range 50–300 K have been carried out on gold–fluorocarbon–polymer composite films. Such measurements have been performed on samples with different percentages in volume of gold, before and after thermal annealing up to 450 K. The experimental temperature dependence of conduc…
The pretilt angle and the anchoring strength are important parameters in liquid crystal displays (LCDs). However, in the case of amorphous LCDs (a-LCDs), it is difficult to evaluate these parameters by means of conventional measurement method due to non-uniformity of the LC directors. In this paper, we report the simu…
Abstract A new negative working photosensitive polyimide, based on hyperbranched poly(ether imide) (1), 4,4′-methylenebis[2,6-bis(hydroxymethyl)]phenol (2) as a cross-linker, and a photoacid generator diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate (3) has been developed. 1 was prepared by polycondensation of N-…
The thermal behaviour of two series of liquid crystalline carbosilane dendrimers of generations 1–5 containing 8, 16, 32, 64 and 128 terminal phenyl benzoate mesogenic groups, respectively, was investigated by means of polarising optical microscopy, DSC and X-ray methods. Mesogenic groups on the base of methoxybenzoic…
Crack-tip opening displacement (CTOD) fracture toughness measurements have been performed on longitudinal, through-wall thickness, three-point bend samples from an X-80 pipeline steel. Samples were subjected to cathodic protection in an NS-4 test solution prior to and during fracture toughness determination. Variation…
The mechanical properties of Si 3 N 4 materials depend mainly on the microstructure, which originates during the densification process. The microscopic evidence indicates that β‐Si 3 N 4 seeds incorporated in the starting powders play an important role in microstructural development, especially in the heterogeneous gr…
Abstract Clay mineral diagenesis in the Niigata basin is documented by mineralogical and chemical analysis of clay minerals from cuttings from the Shinkumoide SK-1D (SSK-1D) well which is characterized by alternating beds containing dioctahedral and trioctahedral smectite minerals with increasing depth. Dioctahedral s…
Abstract Spontaneous appearance of polypyrrole microtubes was first observed during the electrochemical polymerization of pyrrole in water using sodium p-toluenesulfonate as a supporting salt. Almost amorphous microtube showed high electrical conductivity (σ = 498 S cm−1) along an axis of the tube. The tube also revea…
The synthesis and transition temperatures of a series of novel thienyl-pyrimidine liquid crystalline materials is described. Palladium catalysed coupling of 5-n-alkyl-2-tri-n-butylstannyl thiophenes to 5-bromo-2-iodopyrimidine is used to create novel pyrimidine compounds which exhibit lower melting points than similar…
This paper reports on an experimental investigation in which important primary hand attributes of nonwoven fusible interlinings are identified and empirical translation formulas for the attributes are established. These formulas can be used to objectively evaluate the hand of nonwoven fusible interlinings based on mea…
A sample is provided of the radiological safety issues particular to low energy proton accelerators. 'Low' energy in this context is taken to mean proton energies of less than about 1 GeV. Many of the radiation issues are common to all particle accelerators. Here, those issues are addressed that may require perhaps no…
Comprehensive nuclear decay data files used for dose calculation have been compiled using decay data sets from the Evaluated Nuclear Structure Data File (ENSDF), the latest version in August 1997. The compiled data files contain the decay data for (1) 817 radionuclides that are listed in ICRP Publication 38 (Publ. 38)…
Thin films of cobalt oxide have been deposited on various substrates, such as glass, Si(100), SrTiO3(100), and LaAlO3(100), by low pressure metalorganic chemical vapor deposition (MOCVD) using cobalt(IL), acetylacetonate as the precursor. Films obtained in the temperature range 400-600 degreesC were uniform and highly…
BACKGROUND/AIMS: As skin roughness and wrinkles are easily perceived by the consumer, quantifying skin surface structures is a vital parameter for cosmetic product development. As more tools are available for measuring three-dimensional (3-D) surface data, instead of two-dimensional (2-D) profile lines, new algorithms…
A synchrotron radiation (SR) facility typically consists of an injector, a storage ring, and SR beamlines. The latter two features are unique to SR facilities, when compared to other types of accelerator facilities. The SR facilities have the characteristics of low injection beam power, but high stored beam power. The…
The minerals of the pyrochlore group exhibit a large range of chemical composition. The general structural formula can be written as A2–mB2X6–wY1–n•pH2O. The occupancy of the eight-fold-coordinated A site can reflect the degree of alteration of the pyrochlore. In unaltered pyrochlore-group minerals, this site is compl…
First principles techniques have been employed to examine the isolated self-interstitial in diamond. The assignment of the R2 EPR center to the self-interstitial has been questioned because of the small fine structure term. We have calculated the spin–spin interaction tensor, which resolves the problem. We have also m…
Optical properties of porous graphite samples prepared by electrochemical etching were investigated. It is found that electrochemical etching modifies their Raman spectra and gives rise to photoluminescence. The evolution of Raman spectra at the initial etching stages is studied in detail. A model is proposed explaini…
The orientational behaviour of the nematic discotic phase of 2,3,6,7,10,11-hexa(4-n-octyloxybenzoyloxy)triphenylene (C8OBT) on substrates coated with a polyimide or cetyltrimethylammonium bromide (CTAB) was investigated by polarizing optical microscopy. The averaged order parameters and directions of the triphenylene…