A Fe-10.5Mn-0.06C steel consisting of austenite and ferrite dual phases with a volume fraction ratio of 7:3 was fabricated via the quenching and partitioning (Q&P) processing. Tensile tests at ...various temperatures and strain rates were performed to reveal the mechanical properties of the steel, and the deformation microstructures were characterized by using TEM, t-EBSD and APT techniques. At a constant strain rate of 0.1 s−1, yield strength, tensile strength increase as the temperature decreases from 100 °C to −50 °C, and reach the highest values of 560 MPa and 1390 MPa at −50 °C, respectively. The specimens deformed at low temperatures (below 200 °C) exhibit a characteristic of three-stage work-hardening behavior, while those deformed at higher temperatures (200 and 300 °C) only show two-stage work-hardening curves. The extra hardening stage found at low temperatures is associated with the concurrent twinning and transformation in austenite with varying Mn contents as well as the interaction between twins and dislocations. With increasing temperature, the diffusion of Mn from austenite to ferrite is depressed, inhibiting the martensitic transformation. Consequently, the TRIP effect is weakened and the steel shows the reduced work-hardening rates at higher temperatures. In addition, a few nanoscale austenite residues (<200 nm) are remained even after −25 °C tensile deformtion, due to the highly localized Mn concentration of ∼15 wt%. These findings provide a guidance for designing advanced materials with combinations of ultrahigh strength and good ductility.
A numerical model including 29 reactions and 11 species is developed to investigate the spatial-temporal distributions of species and electric field in oxygen parallel-plate positive pulsed ...dielectric barrier discharge for ozone generation. Electron energy conservation equation is coupled to electron continuity equation, heavy species continuity equation and Poisson's equation. The spatial-temporal distributions of species and electric field are obtained at electron avalanche and during streamer propagation. The results show the dominant positive ion, negative ion and excited species are O2+, O3− and O2(∑g+1), respectively. The average streamer propagation velocity is about 5.56 × 104 m/s. Overall electron density almost increases exponentially but with a violent oscillation in the vicinity of anode at electron avalanche. Electron density increases at first and then declines in the vicinity of anode and streamer channel during streamer propagation, and increases gradually in streamer head with the development of streamer, as well as reduces sharply to almost zero near cathode. Electron density almost remains constant in whole streamer channel at any one moment. Other species have a similar spatial-temporal distribution.
•A plasma fluid and chemical model coupling electron energy conservation is developed.•Spatial-temporal distribution of species and electric field were obtained in oxygen pulsed DBD.•Obvious oscillations present near anode and the streamer propagation velocity is about 5.56 × 104 m/s.
We explore the second order bilinear magnetoelectric resistance (BMER) effect in the d-electron-based two-dimensional electron gas (2DEG) at the SrTiO3(111) surface. We find evidence of a spin-split ...band structure with the archetypal spin-momentum locking of the Rashba effect for the in-plane component. Under an out-of-plane magnetic field, we find a BMER signal that breaks the sixfold symmetry of the electronic dispersion, which is a fingerprint for the presence of a momentum-dependent out-of-plane spin component. Relativistic electronic structure calculations reproduce this spin texture and indicate that the out-of-plane component is a ubiquitous property of oxide 2DEGs arising from strong crystal field effects. We further show that the BMER response of the SrTiO3(111) 2DEG is tunable and unexpectedly large.
As one of the most promising first wall/blanket structure materials in fusion reactors, oxide dispersion strengthened (ODS) ferritic steel has been extensively studied in past decades. The grain size ...of ODS steels is often between 200 and 1000 nm, called ultrafine-grained (UFG). Refining their grain size, if possible, should further enhance their radiation tolerance. In the present work, we report on a novel zirconium-doped nanocrystalline (NC) 14YWTZ ODS steel composed of a ferritic matrix with an average grain size of 50 nm and high-density oxide nanoprecipitates with an average diameter of 3.3 nm. Both NC and UFG 14YWT ODS steels were irradiated with helium ions at 450 °C. Abnormal lattice shrinking and narrowing of X-ray diffraction peaks are found in irradiated NC ODS steel. The NC ODS steel has an extremely high sink strength of ∼ 3 × 1016 m−2, which is mainly contributed by grain boundaries and effectively inhibits the aggregation of He atoms and the growth of He bubbles. The bubble size, void swelling, and irradiation hardening in NC ODS steel irradiated at a high dose, when compared to those in UFG ODS steel, are significantly smaller. The underlying mechanisms for the high irradiation tolerance in the NC ODS steel are discussed. This work provides an approach to further enhancing the radiation resistance of conventional UFG ODS steels by refining their grain size to nanoscale dimensions.
Realization of long-distance quantum communication through the quantum repeater network requires a combination of some key elements, including a multiplexed quantum memory for storage of entanglement ...and a telecom photon for propagation of information through the fiber. Although impressive experimental advances have demonstrated the individual elements, combining these key capabilities together and realizing them in a single experimental system remains a significant challenge. Here, we report an experimental realization of long-distance entanglement between a multiplexed quantum memory with 49 individually accessible memory cells and a telecom photon after transmission in a 10-km optical fiber. Excitation of an atomic ensemble generates narrow-band polarization entanglement between a telecom photon of 1530-nm wavelength and another photon of 780-nm wavelength, which is then stored into a memory cell of a multiplexed atomic quantum memory and read out after a controllable delay. The entanglement is verified through quantum-state tomography after quantum storage in the atomic memory and fiber transmission of the telecom photon. This experiment demonstrates an important step towards realization of long-distance quantum communication networks.
The Sonic hedgehog (SHH) protein produced in the zone of polarising activity (ZPA) is a major determinant of the identity and numbers of digits in early limb development. Preaxial polydactyly types ...II (PPD2) and III (PPD3) have been mapped to a critical region at 7q36, and subsequently shown to be caused by point mutations in the ZPA regulatory sequence (ZRS), a long range cis-regulator for the SHH gene. Triphalangeal thumb-polysyndactyly syndrome (TPTPS) and syndactyly type IV (SD4) were also mapped to the 7q36 region but pathogenic mutations in ZRS have not yet been affirmed.
We performed linkage and haplotype analysis in six Han Chinese families with TPTPS and/or SD4, and refined the disease locus to an interval of 646 kb containing ZRS. In all families, the affected individuals heterozygous at rs10254391 (a single nucleotide polymorphism within ZRS) revealed a remarkable allele imbalance on sequence chromatogram. Using real-time quantitative polymerase chain reaction (qPCR), we identified duplication of ZRS and found that this duplication segregated with the limb phenotypes in all families but was not detected in unaffected family members or in unrelated control individuals. The duplication was also confirmed by interphase fluorescence in situ hybridisation (FISH) in an affected individual. We designed 17 additional qPCR assays and defined the minimum duplications in all six families, ranging from 131kb to 398kb.
Both TPTPS and SD4 are due to duplications involving ZRS, the limb specific SHH enhancer. Point mutations in the ZRS and duplications encompassing the ZRS cause distinctive limb phenotypes.
The maximum potential of a dual-loop organic Rankine cycle (ORC) applied to a light-duty diesel engine is analyzed over the engine's operational range by developing a mathematical model based on ...physical processes and boundary conditions specified according to measured data from an engine test. We further evaluate the effects of three working parameters—expander isentropic efficiency, evaporation pressure of the high-temperature loop, and condensation temperature of the low-temperature loop—on the performance of the dual-loop ORC system. The results show that using the proposed dual-loop ORC system improves the net power output of a diesel automotive engine by 19–22% in the peak thermal-efficiency region under allowable working conditions of the engine, and by 53–72% in the high-speed and low-load regions. Over the engine's entire operational range, the effective thermal efficiency increases by a maximum of 8%. Moreover, the expander isentropic efficiency and the condensation temperature of the low-temperature loop are two critical parameters that affect combined system performance.
•The potential of a dual loop ORC is estimated over the engine's operating region.•Effect of expander isentropic efficiency is analyzed at engine speed of 1800 r/min.•Evaporation pressure and condensation temperature are also evaluated.
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