Core-shell nanoparticle arrays double the strength of steel

Manipulating structure, defects and composition of a material at the atomic scale for enhancing its physical or mechanical properties is referred to as nanostructuring. Here, by combining advanced microscopy techniques, we unveil how formation of highly regular nano-arrays of nanoparticles doubles the strength of an Fe-based alloy, doped with Ti, Mo, and V, from 500 MPa to 1 GPa, upon prolonged heat treatment. The nanoparticles form at moving heterophase interfaces during cooling from the high-temperature face-centered cubic austenite to the body-centered cubic ferrite phase. We observe MoC and TiC nanoparticles at early precipitation stages as well as core-shell nanoparticles with a Ti-C rich core and a Mo-V rich shell at later precipitation stages. The core-shell structure hampers particle coarsening, enhancing the material's strength. Designing such highly organized metallic core-shell nanoparticle arrays provides a new pathway for developing a wide range of stable nano-architectured engineering metallic alloys with drastically enhanced properties. ?The Author(s) 2017.1116Ysciescopu

Teatro e ensino da matemática: atividade desenvolvida num curso de formação docente

Anais do II Seminário Seminário Estadual PIBID do Paraná: tecendo saberes / organizado por Dulcyene Maria Ribeiro e Catarina Costa Fernandes — Foz do Iguaçu: Unioeste; Unila, 2014Este trabalho relata uma aula desenvolvida pelas alunas do Curso de Formação de Docentes do Instituto Estadual de Educação de Londrina com a colaboração dos Bolsistas do Programa Institucional de Bolsas de Iniciação à Docência – PIBID – Subprojeto de Matemática, para alunos de primeiro ano do Ensino Fundamental utilizando o teatro como forma de apresentar conteúdos matemáticos como números, sequência de números, operações básicas como adição, subtração e conteúdos de língua portuguesa como leitura e escrita de número

DESIGN OF THE 4 MeV RFQ FOR THE HELIUM BEAM IRRADIATOR*

Abstract A radio frequency quadrupole (RFQ) is considered as a main accelerator of the helium beam irradiation system for the power semiconductor in Korea Multipurpose Accelerator Complex (KOMAC) The RFQ was designed to accelerate the He2+ beam up to 4 MeV with 10 mA peak beam current. We chose a vane type RFQ with 200 MHz operating frequency. The RFQ will be operated with the frequency tracking mode supplied by the digital low level RF control system. In this paper, the design of the 4 MeV RFQ is presented and the beam irradiation system including RF system, control system, utility system, is discussed

Realization of the welding of individual TiO2 semiconductor nano-objects using a novel 1D Au80Sn20 nanosolder

Individual semiconductor nanowires (NWs) TiO2 were successfully welded together using novel one-dimensional (1D) Au80Sn20 (mass ratio) nanosolders at the nano-scale for the first time. The nanosolders were electrodeposited into nanoporous templates to form a 1D structure, and their morphology, crystal structure, chemistry and elemental electronic states were systematically characterized. Individual Au80Sn20 nanowires were proved to consist of mixed crystal phases, including a Au5Sn phase with a trigonal structure, a AuSn phase with a hexagonal structure and a small SnO2 phase produced the by oxidation of the surface portion. Chemical analysis indicated that the composition was Au80Sn20. The testing of the welding capability by either in situ TEM or in situ SEM by nanomanipulators and infiltration experiment revealed a good wet ability and diffusion ability between the Au80Sn20 nanosolder and the TiO2 nanowire. It is believed that our study contributes to the field a special nanosolder for future nano-scale welding techniques, which also make the bonding of titanium-based semiconductor oxide nanomaterials at the nano-scale a reality

Randomized Comparison of Four-Times-Daily versus Once-Daily Intravenous Busulfan in Conditioning Therapy for Hematopoietic Cell Transplantation

AbstractSixty patients were randomized to receive intravenous busulfan (iBU) either as 0.8 mg/kg, over 2 hours 4 times a day (BU4 arm) or 3.2 mg/kg, over 3 hours once a day (BU1 arm) in conditioning therapy for hematopoietic cell transplantation. The complete pharmacokinetic parameters for the first busulfan dose were obtained from all patients and were comparable between the 2 arms: for the BU4 and BU1 groups, elimination half-life (mean ± SD) was 2.75 ± 0.22 versus 2.83 ± 0.21 hours, estimated daily AUC was 6058.0 ± 1091.9 versus 6475.5 ± 1099.4 μM·min per day, and clearance was 2.05 ± 0.36 versus 1.91 ± 0.31 mL/min/kg, respectively. Times to engraftment after transplantation were similar between the 2 arms. No significant differences were evident in the occurrence of acute graft-versus-host disease (aGVHD) and hepatic veno-occlusion disease (VOD). Moreover, other toxicities observed within 100 days after transplantation were not significantly different between the 2 arms. The cumulative incidence of nonrelapse mortality was 20.8% in BU4 arm and 13.3% in BU1 arm. In conclusion, our randomized study demonstrates that the pharmacokinetic profiles and posttransplant complications are similar for once-daily iBU and traditional 4-times-daily iBU