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Nanocrystalline alloy samples with the same chemistry (Fe86B13Cu1) but with a range of mean grain sizes were prepared in order to investigate the effect of the grain size (D) on the core losses in nanocrystalline alloys. The core loss was measured on an Epstein frame in a frequency range between 10 Hz and 30 kHz. The measured core loss was separated into 3 parts, i.e. the hysteresis loss, classical eddy current loss and the excess loss. The classical eddy current loss is only a minor component due to the small thickness and moderately high electrical resistivity of the samples. Both the coercivity and the cycle hysteresis loss are found to follow roughly a D3 dependence. The excess loss at the maximum polarization (Jm) between 0.6 and 1.0 T is described universally by a simple power dependence of (Jm·f)n with an exponent of about 1.4 over a wide frequency (f) range between 10 Hz to 30 kHz. The excess loss at low frequencies appears almost independent of the grain size. Thus, the grain size effect on the total loss at low frequencies is attributable to the change in the hysteresis loss which reflects the static coercivity. However, the excess loss at 30 kHz shows a clear increase with an increase in D, indicating that the excess loss also becomes influential to the grain size dependence of the total core loss at high frequencies.

We investigated, using molecular dynamics, how pressure affects the melting point of the recently theorised and epitaxially grown structure NdFe12. We modified Morse potentials using experimental constants and a genetic algorithm code, before running two-phase solid-liquid coexistence simulations of NdFe12 at various temperatures and pressures. The refitting of the Morse potentials allowed us to significantly improve the accuracy in predicting the melting temperature of the constituent elements.

Nanocrystalline soft magnetic materials are known to be prepared by primary crystallization of Fe-based amorphous precursors. Since the crystallization reaction is exothermic, the amorphous precursor may experience a temporary rise in its temperature relative to its surroundings during the process of nanocrystallization. Given the typical latent heat of primary crystallization (∼ 100 kJ/kg), this temperature rise may exceed hundreds of degrees if not adequately controlled and thus, lead to the formation of unwanted magnetically hard compounds. This effect is generally small for isolated ribbons annealed with a moderate heating rate. However, the recent adoption of high heating rates and short annealing times has caused the self-heating effect to become relevant even for small sample sizes. In this work, the effect of self-heating on the microstructure and magnetic properties of nanocrystalline Fe86B14 is investigated. It is found that magnetically hard Fe-B compounds cannot be avoided when annealing under vacuum in an infrared furnace with a heating rate ≥3 K/s due to the self-heating effect. However, the high thermal conductivity of the copper blocks used by the ultra-rapid annealing process can successfully prevent a self-heating induced temperature rise during annealing, avoiding unwanted compound formation. Finite Element Analysis is also used for predicting the extent of self-heating during infrared annealing.

A brief survey of the recent advances in Fe-based nanocrystalline soft magnetic alloys has shown that the saturation magnetization (Js) of these alloys is governed by the mass fraction, rather than the atomic fraction, of the nonmagnetic additives. Thus, the ultimate limit of Js in the alloys prepared by nano-crystallization of amorphous precursors is expected in an Fe-B binary system where amorphization by rapid quenching takes place with the lowest mass fraction of glass forming elements in Fe-based systems. We will demonstrate that nano-crystallization is possible in this binary system when the precursor amorphous phase is annealed ultra-rapidly. While the grain size after conventional annealing for amorphous Fe-B alloys is too large for the exchange softening effect, a small grain size well below the exchange length is obtained after annealing with a heating rate of 103 – 104 K/s. This results in magnetically soft nanostructures with Fe content up to 97.2 wt. %, leading to a high Js ≥ 1.9 T with a small coercivity (Hc) between 3.8 and 6.4 A/m. An addition of Co to nc-Fe87B13 results in a higher Js of 2.0 T with a slight increase of Hc to 9.3 A/m. The soft magnetic properties of these ultra-rapidly annealed alloys (named HiB-Nanoperm) is well understood by the random anisotropy model. The formation of nano-meter scale microstructures in a simple binary system unlocks previously unavailable alloy design strategies in nanostructured systems which is not only relevant to magnetic materials but, also to structural materials.

Nd80Ga15Cu5 and Nd62Fe14Ga20Cu4 alloys were used as diffusion sources for the eutectic grain boundary diffusion process, applying to 4 mm-thick Nd-Fe-B hot-deformed magnets. Both samples showed nearly same coercivity of 2.2 T, while the sample processed with Nd62Fe14Ga20Cu4 showed smaller remanence deterioration from 1.50 T to 1.30 T, in contrast to that of the sample processed with Nd80Ga15Cu5 to 1.08 T. Mr/Ms of the initial sample and the samples processed with Nd62Fe14Ga20Cu4 and Nd80Ga15Cu5 were 0.946, 0.934 and 0.917, respectively, suggesting that the sample processed with Nd62Fe14Ga20Cu4 retains stronger c-axis texture after the diffusion process. Nd-rich phases with Ia3¯ and fcc structures were observed in the sample processed with Nd80Ga15Cu5, while the Nd-rich phases with the Ia3¯ and hcp structures were found in the sample processed with Nd62Fe14Ga20Cu4, all of which are the phases commonly observed in Nd-Fe-B sintered magnets.

Conjugate gradient methods for energy minimization in micromagnetics are compared. The comparison of analytic results with numerical simulation shows that standard conjugate gradient method may fail to produce correct results. A method that restricts the step length in the line search is introduced, in order to avoid this problem. When the step length in the line search is controlled, conjugate gradient techniques are a fast and reliable way to compute the hysteresis properties of permanent magnets. The method is applied to investigate demagnetizing effects in NdFe12 based permanent magnets. The reduction of the coercive field by demagnetizing effects is μ0ΔH = 1.4 T at 450 K.

Ce-based R2Fe14B (R= rare-earth) nano-structured permanent magnets consisting of (Ce,Nd)2Fe14B core-shell grains separated by a non-magnetic grain boundary phase, in which the relative amount of Nd to Ce is higher in the shell of the magnetic grain than in its core, were fabricated by Nd-Cu infiltration into (Ce,Nd)2Fe14B hot-deformed magnets. The coercivity values of infiltrated core-shell structured magnets are superior to those of as-hot-deformed magnets with the same overall Nd content. This is attributed to the higher value of magnetocrystalline anisotropy of the shell phase in the core-shell structured infiltrated magnets compared to the homogeneous R2Fe14B grains of the as-hot-deformed magnets, and to magnetic isolation of R2Fe14B grains by the infiltrated grain boundary phase. First order reversal curve (FORC) diagrams suggest that the higher anisotropy shell suppresses initial magnetization reversal at the edges and corners of the R2Fe14B grains.

A rare case of mucinous adenocarcinoma of the cecum in a pregnant woman is described. A 32-year-old Korean woman was diagnosed as having an abdominal tumor immediately after giving birth. Abdominal computed tomography demonstrated a smooth mass measuring 10 cm in diameter on the right side of the abdomen. Acute abdomen developed 3 days after birth. At emergency surgery, volvulus of a polypoid tumor was detected at the cecum apart from the normal appendix. We successfully performed a tumorectomy; however, histopathological examination demonstrated mucinous adenocarcinoma with a massive blood clot.

Dos tipos de aceros inoxidables austeníticos, JJl y JNl, se envejecieron isotérmicamente a temperaturas entre 873 y 1.173 K por tiempos de 10 a 1.000 min, para estudiar la evolución microestructural y su efecto sobre la tenacidad a la fractura a temperaturas criogénicas. Los métodos de ensayo de impacto Charpy y el ensayo miniatura de embutido se llevaron a cabo a 77 K para evaluar la tenacidad de las muestras tratadas térmicamente. La energía de fractura determinada por ambos métodos mostró una disminución con el tiempo de envejecido para ambos aceros. Se encontró una relación lineal entre ambos valores de energía. La precipitación intergranular de carburos y nitruros fue la responsable de la pérdida de la tenacidad en las muestras envejecidas. La fractografía indicó que la fractura intergranular se incrementa con la temperatura y el tiempo de envejecido. La presencia de una precipitación intergranular abundante dio, como resultado, una más rápida disminución de la tenacidad a la fractura con, el tiempo de envejecido para el acero JNl, debido a su mayor contenido de carbono y nitrógeno, comparado con el acero JJ1.

The quality of hazard identification has a significant impact on the quality of overall risk assessment and occupational accident prevention in workplace. Currently accepted hazard identification approaches tend to rely on knowledge of previous accidents, experience of the task, and participants’ imagination, although hazard identification itself is most important for new tasks and novices who do not have experiences of the same or similar tasks. This paper outlines a logical hazard identification method based on a concept for object-based energy analysis as a tool that does not require experience, knowledge of tasks, or imagination. The method is derived from a physical principal and the analysis of occupational accidents. This method is expected to enable users to identify hazards effectively and easily, and contribute to successful risk assessment.

We demonstrate efficient wavelength conversion using a four-wave-mixing (FWM) effect in a silicon photonic wire waveguide with spot size converters. Applying a continuously operated 160-mW pump, power density in the waveguide's core was increased up to around 430 MW/cm2, and the FWM effect was remarkably enhanced. Internal conversion efficiency obtained in an experiment was -10.6 dB. The efficiency was significantly limited by the free-carrier absorption effect. [ABSTRACT FROM PUBLISHER]

Magnetically soft nanostructures are known to be prepared by the primary crystallisation of Fe-based amorphous precursors containing Cu and/or Nb. These nonmagnetic additives are essential for accelerated nucleation and retarded crystal growth during crystallisation. However, it has recently been found that none of these additives are necessary for the preparation of similar nanostructures when ultra-rapid annealing (URA) is employed. As a result, a magnetically soft nanostructure with exceptionally high Fe contents is realized in a simple Fe–B binary system. An obvious question is the mechanism of the nanostructural formation in such a simple system. To answer this question, the crystallisation behaviour of amorphous precursors was investigated by means of in situ resistivity measurements with heating rates up to ~100 K s−1. The primary crystallisation temperature (Tp) in Fe86B14 is increased at least by ~100 K under URA. This brings Tp to the vicinity of the glass transition (Tg) predicted by Egami’s zeroth-order approximation, suggesting that an enhanced nucleation rate near Tg due to the contribution of homogeneous nucleation could be responsible for the nanostructural formation in Fe86B14. Contrarily, the effect of URA is absent from Fe80B14Nb6, and a magnetically soft nanostructure is realized by conventional annealing because the crystallisation reaction in this alloy takes place above Tg even with a low heating rate of ~1 K s−1. URA offers new possibilities for enhancing the saturation magnetization in nanocrystalline soft magnetic alloys through reductions of the amount of nonmagnetic additives. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the performance of ClairvivoPET using NEMA NU4 standards. The ClairvivoPET incorporates a LYSO dual depth-of-interaction detector system with 151 mm axial field of view (FOV). Spatial resolution, sensitivity, counting rate capabilities, and image quality were evaluated using NEMA NU4-2008 standards. Normal mouse imaging was also performed for 10min after intravenous injection of 18F(-)-NaF. Data were compared with 19 other preclinical PET scanners. Spatial resolution measured using full width at half maximum on FBP-ramp reconstructed images was 2.16 mm at radial offset 5 mm of the axial centre FOV. The maximum absolute sensitivity for a point source at the FOV centre was 8.72%. Peak noise equivalent counting rate (NECR) was 415kcps at 14.6MBq ml−1. The uniformity with the image-quality phantom was 4.62%. Spillover ratios in the images of air and water filled chambers were 0.19 and 0.06, respectively. Our results were comparable with the 19 other preclinical PET scanners based on NEMA NU4 standards, with excellent sensitivity because of the large FOV. The ClairvivoPET with iterative reconstruction algorithm also provided sufficient visualization of the mouse spine. The high sensitivity and resolution of the ClairvivoPET scanner provided high quality images for preclinical studies. [ABSTRACT FROM AUTHOR]

Mitochondria are organelles that produce energy for embryogensis. Their function [oxidative phosphorylation (OXPHOS) and electron transport] is regulated by intercommunication with the nucleus. In somatic cell nuclear transfer (SCNT) embryos, incomplete reprogramming may lead to dysfunction of the intercommunication before or after embryonic activation, or both, although it is unknown whether reprogramming for energy synthesis is required. In the previous report (Abe et al. 2004 J. Mamm. Ova Rec. 21, 22), we developed a noninvasive method using a scanning electrochemical microscopy (SECM) for measurement of oxygen consumption that provides more direct information about mitochondrial function (Trimarch et al. 2000 Biol. Reprod. 62, 1866–1874). In the present study to evaluate mitochondrial function in individual miniature pig SCNT embryos, we measured oxygen consumption by SECM. Oocytes in pig ovaries collected from the local slaughterhouse were matured for 44 h in NCSU23 and used as recipient. After SCNT with fetal miniature pig fibroblasts, reconstructed embryos were cultured in vitro in NCSU23 or PZM-3. Oxygen consumption in single 2- and 4-cell-stage embryos, morulae, and blastocysts were measured, and the values were compared with those derived from IVF. All data were analyzed by ANOVA. In IVF embryos, oxygen consumption was lowest at the 2- and 4-cell stages, and reached a peak at the blastocyst stage on Day 5. However, there were significant differences (P < 0.05) in blastocysts between NCSU23 and PZM-3: 0.61 0.14 vs. 0.83 0.18 at Day 5, 0.53 0.14 vs. 0.70 0.24 at Day 6, 0.47 0.11 vs. 0.73 0.20 10-14 mol s-1 at Day 7, respectively. In contrast, SCNT embryos showed no increase in oxygen consumption during pre-implantation stages in the 2 media, but there was a significant difference (P < 0.05) at the 2-cell stage between NCSU23 and PZM-3 (0.35 0.09 vs. 0.43 0.10, respectively). Comparison of the Day 5 IVF and SCNT blastocysts cultured in PZM-3 showed no difference in total cell numbers but significantly (P < 0.05) lower oxygen consumption in SCNT (0.83 0.18 vs. 0.40 0.13 10-14 mol s-1, respectively). After treatment with 1 M CCCP (mitochondrial uncoupler) or 1 mM NaCN (mitochondrial electron transporter inhibitor), oxygen consumption in IVF and SCNT blastocysts at Day 5 increased (112 18 and 51 44%, respectively) or decreased (50 20 and 21 32%, respectively) compared with those of nontreated embryos. Sensitivity to these reagents differed significantly (P < 0.05) between IVF and SCNT, indicating that the SCNT blastocysts had a lower OXPHOS capacity than those from IVF. These results suggest that reprogramming for sustaining mitochondrial function during pre-implantation development may be required in miniature pig SCNT embryos. [ABSTRACT FROM AUTHOR]