Ultraviolet Laser Action in Ferromagnetic Zn1?xFexO Nanoneedles

Fe-doped ZnO nanoneedles (NDs) were fabricated by an Ar⁺ ion sputtering technique operated at room temperature. The as-grown samples show both ferromagnetic and lasing properties. The saturated magnetization moment was measured from 0.307 to 0.659 emu cm⁻³ at the field of 10 kOe with various Fe concentrations. Intense ultraviolet random lasing emission was observed from Zn_1 − x Fe _x O NDs at room temperature. The X-ray photoelectron spectroscopy result reveals that the doped Fe atoms occupy the Zn sites and lead to a decrease in oxygen deficiency.     

The influence of operating parameters on pulsed D.C. magnetron sputtering plasma

This paper describes the breakdown voltage characteristics in a pulsed D.C. magnetron sputtering system under varying conditions of frequency, current and pulse-off time. The behaviour of the breakdown voltage with pulsing frequency at different pressures and constant pulse-off time was recorded and revealed that the breakdown voltage decreased consistently as the frequency increased up to 70 kHz. Above this frequency, perturbation in the breakdown voltage was noted, possibly due to the rise in pre-breakdown current during the few microseconds of pulse-on time. This perturbation effect was no longer observed when the operating current was increased. The breakdown voltage was seen to decrease when the pulse-off time was increased while keeping the total period of the pulse constant.     

A structure zone diagram including plasma-based deposition and ion etching

An extended structure zone diagram is proposed that includes energetic deposition, characterized by a large flux of ions typical for deposition by filtered cathodic arcs and high power impulse magnetron sputtering. The axes are comprised of a generalized homologous temperature, the normalized kinetic energy flux, and the net film thickness, which can be negative due to ion etching. It is stressed that the number of primary physical parameters affecting growth by far exceeds the number of available axes in such a diagram and therefore it can only provide an approximate and simplified illustration of the growth condition-structure relationships.     

Continuous biosorption of heavy metal ions by Ca-loadedlaminaria japonica in fixed bed column

Continuous biosorption process for removal of lead and copper by laboratory scale fixed-bed reactor was carried out using Ca-loadedLaminaria japonica. All biosorption processes were observed as cation exchange such as Pb²⁺ vs. Ca²⁺, Cu²⁺ vs. Ca²⁺, and Pb²⁺ vs. Cu²⁺. The affinity of lead ions towardsL. japonica was stronger than that of copper ions because the initial amount of desorbed Cu²⁺ in Cu-Pb system was higher than that of eluted Pb²⁺ in Pb-Cu system.     

The trapped ion–electron instability in an electron storage ring with a gap in the bunch train

The trapped ion–electron instability in an electron storage ring is studied for a broad distribution of natural ion oscillation frequencies, termed ion bounce frequencies. A gap in the train of electron bunches may be used to create bands of unstable ion bounce frequencies, so that an ion species is ejected from regions of the ring where its horizontal or vertical bounce frequency is unstable. Expressions are obtained for the reduction in the incoherent tune shifts and trapped ion–electron instability growth rates resulting from the gap.     

Fluorinated carboxylic membranes deposited by plasma enhanced chemical vapour deposition for fuel cell applications

Among the fuel cell technologies, the polymer electrolyte membrane fuel cells (PEMFCs) are particularly promising because they are energy-efficient, clean, and fuel-flexible (i.e., can use hydrogen or methanol). The great majority of PEM fuel cells rely on a polymer electrolyte from the family of perfluorosulfonic acid membranes, nevertheless alternative materials are currently being developed, mainly to offer the alternative workout techniques which are required for the portable energy sources. Plasma polymerization represents a good solution, as it offers the possibility to deposit thin layer with an accurate and homogeneous thickness, even on 3D surfaces. In this paper, we present the results for the growth of proton conductive fluoro carboxylic membranes elaborated by plasma enhanced chemical vapour deposition. These membranes present conductivity values of the same order than the one of Nafion^®. The properties of the membrane, such as the chemical composition, the ionic conductivity, the swelling behaviour and the permeability were correlated to the plasma process parameters. The membranes were integrated in fuel cells on porous substrates and we present here the results regarding the barrier effect and the power output. Barrier effect similar to those of 40 μm Nafion^® layers was reached for 10 μm thick carboxylic membranes. Power outputs around 3 mW cm⁻² were measured. We discuss the results regarding the gas barrier effect and the power outputs.     

Kinetic Studies on the Exchange of Bivalent Metal Ions on Amberlite IRC‐718—An Iminodiacetate Resin

Abstract

The rate of uptake of alkaline earth metals, copper, and lead have been investigated by a chelating ion exchange resin containing iminodiacetic acid as ligand attached to the copolymer of styrene and divinyl benzene of macroporous matrix structure. It binds alkaline earth metals, Cu, and Pb by the formation of chelate complexes with the carboxylate group of this resin. The experiments discussed in this work have allowed to establish the paramount importance of the presence of this chelating group in obtaining practically useful rates of metal ion uptake. The kinetic parameters like diffusion coefficient (D _o), activation energies (ΔE _a) and entropy of activation have been evaluated under the conditions favoring a particle diffusion control mechanism and the study followed the three models i.e., Nernst Planck, B _t technique and Ash model. K _d values in demineralised water (DMW) were found in the order Cu²⁺ > Pb²⁺ > Mg²⁺ > Sr²⁺ > Ba²⁺ > Ca²⁺.     

Morphological changes of gel-type functional polymers after intermatrix synthesis of polymer stabilized silver nanoparticles

This paper reports the results of intermatrix synthesis (IMS) of silver metal nanoparticles (Ag-MNPs) in Purolite C100E sulfonic ion exchange polymer of the gel-type structure. It has been shown that the surface morphology of the initial MNP-free polymer is absolutely smooth, but it dramatically changes after the kinetic loading of Ag on the polymer and then IMS of Ag-MNPs. These morphological changes can be explained by the interaction of Ag-NPs with the polymer chains, leading to a sort of additional cross-linking of the polymer. As a result, the modification of the gel-type matrix with Ag-MNPs leads to the increase of the matrix cross-linking, which results in the increase of its surface area and the appearance of nanoporosity in the polymer gel. Ag-MNPs are located near the polymer surface and do not form any visible agglomerations. All these features of the nanocomposites obtained are important for their practical applications in catalysis, sensor applications, and bactericide water treatment.     

Anion conductive poly(tetraphenyl phthalazine ether sulfone) containing tetra quaternary ammonium hydroxide for alkaline fuel cell application

The poly(tetraphenyl ether ketone sulfone)s (PTPEKSs) were synthesized from 1,2-bis(4-fluorobenzoyl)-3,4,5,6-tetraphenyl benzene (BFBTPB) and bis(4-fluorophenyl) sulfone with bis(4-hydroxydiphenyl) sulfone in sulfolane. The synthesis of poly(tetraphenyl phthalazine ether sulfone)s (PTPPESs) was carried out via an intramolecular ring-closure reaction of dibenzoylbenzene moiety with hydrazine monohydrate. The PTPPES-QAHs [poly(tetraphenyl phthalazine ether sulfone-quaternary ammonium hydroxide)]s were synthesized via chloromethylation of PTPPES, quaternization with trimethylamine, and followed by an anion exchange of tetra-quaternary ammonium chloride polymers with KOH. Different contents of quaternized unit in PTPPES-QAH (15, 20, 25 mol% of BFBTPB) were studied by FT-IR, ¹H NMR spectroscopy, and thermogravimetric analysis (TGA). Sorption experiments were conducted to observe the interaction of quaternized polymers with water. The ion exchange capacity (IEC), ion conductivity and cell performance of PTPPES-QAH were evaluated with increasing the degree of quaternization.     

Ultra Whey 99: a whey protein isolate case study

A case history of the manufacture and use of whey protein isolate is presented and particular attention is paid to the nutritional and processing characteristics of Ultra Whey 99, a whey protein isolate manufactured by Volac International Ltd. The growth of the nutritional bar market in the USA is used to demonstrate the increasing demand for specialist products such as whey protein.