Materials Literature
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There is a growing demand for the examination of protein microcrystals at third-generation synchrotron sources. After successful pilot experiments at EMBL/ESRF, which proved that protein microcrystals are often suitable for data collection, operation of the microfocus beamline ID13 was made more user-friendly and suit…
We report the observation of photoluminescence (PL) originating from defects created by the visible and near-infrared irradiation of vitreous silica. Three PL bands at 283, 468, and 558 nm exhibited excitation spectra peaking at 250 nm, which corresponds to the oxygen vacancy defect ${V}_{\mathrm{O}}$ absorption. The…
Er 2 O 3 ‐doped PbO‐Bi 2 O 3 ‐Ga 2 O 3 glasses were prepared through the conventional melt‐quenching method, and the energy transfer mechanisms in Er 3+ were investigated. The fluorescent emission at 2.73 μm, which is normally quenched in silicate glasses, became evident because of the low phonon energy of PbO‐Bi 2 O…
The latest results on the use of porous silicon (PS) as an antireflection coating (ARC) in simplified processing for multicrystalline silicon solar cells are presented. The optimization of a PS selective emitter formation results in a 14.1% efficiency multicrystalline (5/spl times/5 cm/sup 2/) Si cell with evaporated…
Bismuth nanocrystals, embedded in amorphous germanium thin films and synthesized by pulsed-laser deposition, are investigated by Raman spectroscopy. Raman spectra are strongly dependent upon the size of the deposited nanocrystals. For the larger nanocrystals, two peaks corresponding to the optical phonons ${A}_{1g}$ a…
The three-dimensional crystal structure of hen apo-ovotransferrin has been solved by molecular replacement and refined by simulated annealing and restrained least squares to a 3.0-A resolution. The final model, which comprises 5312 protein atoms (residues 1 to 686) and 28 carbohydrate atoms (from two monosaccharides a…
The purpose of the present study is to develop an understanding of the photoluminescence properties of Mn 2+ ‐doped zinc silicate (Zn 2 SiO 4 :Mn) phosphors, which have served as a gree‐emitting phosphor in many industrial applications. Thus, several experimental techniques, such as time‐resolved emission spectra, dec…
Constitutive relations for a binary mixture of nearly elastic, circular disks are derived using the Revised Enskog Theory. Viscosity results from hard disk simulations are compared to the Enskog viscosity for a radii ratio of 1.25. The agreement is good up to an area fraction of 0.40. In the Appendix, we provide brack…
The present article examines the in‐plane tensile properties of a two‐dimensional (2D) all‐oxide ceramic composite. The distinguishing characteristics of the material include fine‐scale porosity within the matrix and the absence of a fiber coating. The anisotropy in the elastic‐plastic properties has been studied thro…
The grafting of polystyryllithium onto chloroethyl ether functions of poly(chloroethyl vinyl ether) (PCEVE) chains is a selective reaction which allows the complete substitution of chloride of CEVE units by polystyrene (PS) chains. Since the PCEVE polymer backbone and the PS grafts can be prepared by living cationic a…
The thermal degradation of poly(lactic acid) has been studied using thermal gravimetric analysis over the temperature range 300–700 K, and following a sterilization dose of 50 kGy under vacuum, nitrogen or air. Isothermal weight loss studies have been found to follow complex kinetics with activation energies determine…
To determine the dissipation induced by the surface of fused silica fibers, we measured the quality factor of fibers having various diameters. We measured a maximum quality factor of 21 million and extrapolated to obtain an intrinsic quality factor for fused silica of 30 million. Dissipation in the surface dominated a…
By relating the structural changes measured using the pair density function analysis of pulsed neutron data for ${\mathrm{LaCoO}}_{3},$ we provide evidence for the evolution of the magnetic state with temperature, from the low-spin state to partial occupation of the intermediate spin (IS) and to the high-spin states.…
Nanoporous carbons (NPCs) are useful in adsorptive separations and catalysis, owing to their ability to discriminate between molecules on the basis of size and shape. This property arises from their narrow pore size distribution, which is typically centred at a size corresponding to 0.5 nm. Despite this level of nanor…
This is a review of the recent studies done by the authors in the area of catalysis and photocatalysis by phthalocyanines and related compounds. Several examples of catalytic processes are given. Special attention is paid to the design of new types of photocatalytic systems for photodynamic therapy of cancer and to th…
Electroplated copper exhibits some surprising changes at room temperature in sheet resistance, stress, and microstructure. This behavior, now known as self-annealing, is shown here to be intimately linked to the composition of the plating bath and the resulting incorporation of organic additives in the Cu layer. Their…
Abstract After adsorption, polymer molecules, including proteins, undergo conformational relaxation. It involves a certain degree of spreading of the polymer molecule over the sorbent surface. Adsorption kinetics experiments reveal that the characteristic time of spreading is much longer for globular proteins than for…
Poly(cyclopenta[2,1- b;3,4- b ‘]dithiophen-4-one) (PCDT) has been characterized by several electrochemical and spectroscopic techniques so that it can be used as an active electrode material in electrochemical supercapacitors. This polythiophene derivative was prepared by the electrochemical polymerization of cyclopen…
This study explores the field emission properties of nitrogen-doped diamond grown by microwave plasma chemical vapor deposition. Over 70 nitrogen-doped diamond samples were grown on silicon and molybdenum under varying process conditions. Under certain conditions, films can be grown which exhibit photoluminescence ban…
The ionic model is shown to be applicable to all compounds in which the atoms carry a net charge and their electron density is spherically symmetric regardless of the covalent character of the bonding. By examining the electric field generated by an array of point charges placed at the positions of the ions in over 40…