Conceiving time?: women who do or do not conceive

This article explores the importance of time for an understanding of women's experiences of reproductive identity. In order to do this we draw on data from two separate qualitative research projects. The first project is concerned with the experiences of conception, pregnancy, childbirth and early motherhood in primagravidae, whilst the second focuses on the experiences of individuals (especially women) who defined themselves (at the time of the fieldwork, or some time previously) as 'involuntarily childless' and/or 'infertile'. These two areas are usually treated as separate; however this article explores similarities between them in terms of time and medicalisation. Our central concern then is with exploring the similarities of experience for women who do or do not conceive

In situ detection of dopamine using nitrogen incorporated diamond nanowire electrode

[[abstract]]Significant difference was observed for the simultaneous detection of dopamine (DA), ascorbic acid (AA), and uric acid (UA) mixture using nitrogen incorporated diamond nanowire (DNW) film electrodes grown by microwave plasma enhanced chemical vapor deposition. For the simultaneous sensing of ternary mixtures of DA, AA, and UA, well-separated voltammetric peaks are obtained using DNW film electrodes in differential pulse voltammetry (DPV) measurements. Remarkable signals in cyclic voltammetry responses to DA, AA and UA (three well defined voltammetric peaks at potentials around 235, 30, 367 mV for DA, AA and UA respectively) and prominent enhancement of the voltammetric sensitivity are observed at the DNW electrodes. In comparison to the DPV results of graphite, glassy carbon and boron doped diamond electrodes, the high electrochemical potential difference is achieved via the use of the DNW film electrodes which is essential for distinguishing the aforementioned analytes. The enhancement in EC properties is accounted for by increase in sp2 content, new C–N bonds at the diamond grains, and increase in the electrical conductivity at the grain boundary, as revealed by X-ray photoelectron spectroscopy and near edge X-ray absorption fine structure measurements. Consequently, the DNW film electrodes provide a clear and efficient way for the selective detection of DA in the presence of AA and UA.[[booktype]]紙

Precipitation reactions in the tungsten-nickel-iron heavy alloy system

SIGLELD:D49906/84 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Study of precipitation in 90W-5Ni-5Fe using stereo TEM

Tungsten-based heavy alloys have received considerable attention since 1935 when McLennan and Smithells reported the development of a 90wt%W-balance Ni,Cu alloy that was produced by liquid-phase sintering. In the past fifteen years the majority of heavy alloy research has concentrated on the W-Ni-Fe system because of its superior mechanical properties. The commercially-produced 90W-5Ni-5Fe alloy basically consists of two phases; a network of contiguous bcc W-phase spheroids (98.8at%W-0.1at%Ni-1.1at%Fe) that are 20-30 μm in diameter embedded in a fcc matrix γ-phase (19.2wt%W-41.4wt%Ni-39.4wt%Fe). The mechanical properties of the alloy are governed by the properties and microstructure of the respective phases and the W-γ and W-W boundaries. This contribution is concerned with a precipitation reaction that occurs within the W-phase.</jats:p

Precipitation Hardening in The 90W-5Ni-5Fe Heavy Alloy

ABSTRACTPrecipitation hardening in the W-phase of the 90W-5Ni-5Fe alloy has been identified and monitored by transmission electron microscopy and mechanical tests. Deformation of the alloy prior to aging is observed to accelerate the precipitation reaction. Possible precipitate origin and geometry are discussed in terms of the TEM observations.</jats:p

Precipitation reactions in the tungsten-nickel-iron heavy alloy system

This research is concerned with identifying and characterizing four solid-state precipitation reactions in the W-Ni-Fe system that can be induced by appropriate heat treatments. Previous work in this area is reviewed, and a general overview of the research on this system that may, directly or indirectly, further the understanding of microstructure/mechanical property relationships in the W-Ni-Fe heavy alloy is presented. The many metallographic and analytical techniques that have been employed in the course of this investigation are also briefly reviewed. The specific precipitation reactions studied in the 90W-5Ni-5Fe heavy alloy are listed and briefly described. Interfacial precipitation - interfacial precipitates at the W-andgamma; and andgamma;-andgamma; boundaries were found to be andeta;-carbides. This morphology is expected to severely embrittle the alloy. Matrix-phase precipitation - discontinuous precipitation of W was observed in the matrix region. W-W grain boundary precipitation - W-W grain boundary allotriomorphs (andgamma;-phase) were identified and characterized. W-phase precipitation hardening - fine scale precipitation in the W-phase was found to strengthen the alloy. Deformation prior to aging significantly increased the rate of precipitate nucleation. TEM contrast analysis showed the precipitates to be plate-like with a {100} habit plane, and the strain in the W lattice normal to the precipitates was found to be tensile in nature. Matrix-composition alloys were manufactured to simulate the andgamma;-phase in the 90W-5Ni-5Fe alloy. Metallographic observations of these alloys furthered the understanding of reactions 1) and 2) above. These results are discussed in terms of (a) current theories of solid-state precipitation and (b) the influence of the various morphologies on mechanical properties.</p

In situ HREM observation of interphase boundary motion in 95Pb-5Sn solder

The use of solder to provide mechanical attachment and electrical interconnection for electronic packaging is widespread throughout the industry. One application for a lead-rich solder is in the IC chip/ceramic carrier connection. It is well-established that this joint is susceptible to thermal-fatigue failure and, hence, a thorough microstructural study is warranted. Previous work has shown that 95Pb-5Sn contains β-Sn precipitates that have formed upon solidification and subsequent aging at ambient temperature. Diffraction contrast TEM demonstrated that the precipitates lie on {111}pb habit planes. High-resolution electron microscopy was undertaken to establish whether or not the habit plane was faceted on the atomic level. This contribution reports on an observation of beam-induced precipitate dissolution.</jats:p