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[en] With the help of recent advanced progress in thin film deposition techniques such as molecular beam epitaxy and the ability to exactly control the growth of semiconductor materials, motivated by recent experimental facts of synthesizing much thicker superlattices than pure CrAs such as CrAs/GaAs on GaAs substrates [44], encouraged by many similarities between binary 3d and sp half-metallic ferromagnets, we introduce the superlattice engineering for achieving the possible sp HM materials with ordered structure. Based on first-principles density functional calculations, taking (MX)1/(YX)1 (M=Sr or Ba; X=N, P, or As; Y=Al, Ga, or In) superlattices with zinc-blende structure in the (001) direction as example, we investigate the structural, electronic, and magnetic properties of superlattices embodying sp HM materials as well as answer the question posed in the title. We hope that, these half-metallic ferromagnetic superlattices, at least some of them, could be useful in spintronics.
Journal
[en] Highlights: • The diesel/gasoline/iso-butanol blends were investigated in a CI engine. • Blend with gasoline or iso-butanol produce higher HC emission. • CO increase at low loads and decrease at medium and high loads with blend fuels. • Gasoline or iso-butanol decrease large particles but increase small particles. • Blend fuels reduce total PM number and mass concentrations. - Abstract: In this study, the effects of diesel/gasoline/iso-butanol blends, including pure diesel (D100), diesel (70%)/gasoline (30%) (D70G30, by mass), diesel (70%)/iso-butanol (30%) (D70B30) and diesel (70%)/gasoline (15%)/iso-butanol (15%) (D70G15B15), on combustion and exhaust pollutant emissions characteristics in a four-cylinder diesel engine were experimentally investigated under various engine load conditions with a constant speed of 1800 rpm. The results indicated that D70G30, D70G15B15 and D70B30 delayed the ignition timing and shortened the combustion duration compared to D100. Additionally, CA50 was retarded when engine fuelled with D70G30, D70G15B15 and D70B30 at low engine load conditions, but it was advanced at medium and high engine loads. The maximum pressure rise rates (MPRRs) of D70G30, D70G15B15 and D70B30 were increased compared with D100 except for at engine load of 0.13 MPa BMEP (brake mean effective pressure). Meanwhile, D70G15B15 and D70B30 produced higher brake specific fuel consumption (BSFC) than that of D100. The effects of diesel blend with gasoline or iso-butanol on exhaust pollutant emissions were varied with loads. CO emissions were increased obviously and NOx emissions were decreased under low engine loads. However, CO emissions were decreased and NOx emissions were slightly increased under the medium and high engine load conditions. However, D70G30, D70G15B15 and D70B30 leaded to higher HC emissions than D100 regardless the variation of engine load. Moreover, the particulate matter (PM) (diameter, number and mass concentrations) emissions by using D70G30, D70G15B15 and D70B30 were significantly reduced compared to D100, but more small-size particles were produced.
Journal
[en] Control problem of vertical instability of HL-2M tokamak was studied with DⅢ-D TokSys. The vertical displacement event (VDE) was controlled by the vessel and active conductors, the study of the eigenmodes and current distribution of the vessel greatly reduced the difficulty of modeling, and a mathematical model was set up and parameters of active conductors and the power supply were verified. The growth rates and maximum controllable vertical displacement for different plasma shape configurations with different elongation were calculated. Simulations for snow flake, single null and double null divertors were made in simulink environment by TokSys with a PD controller. Results show that VDE can be controlled very well for different plasma shape configurations. (authors)
Journal
Nuclear Fusion and Plasma Physics; ISSN 0254-6086; 
; v. 37(1); p. 19-24
; v. 37(1); p. 19-24
[en] Highlights: •Anode performances of CMB in the different hybrid electrolytes were compared. •TFSI− anions can participate actively in SEI formation in PP13TFSI/LiPF6 electrolyte. •The hybrid electrolytes show some advantages compared to the constituents alone. -- Abstract: The electrochemical and thermal properties of carbon microbeads (CMB) electrodes with the hybrid electrolytes consisting of varying proportions of N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide (PP13TFSI) and alkyl-carbonate organic solvent are investigated. Particularly, the interfacial properties of CMB/hybrid electrolytes are explored by means of morphologic observations and spectroscopic technologies. It is found that, after the addition of lithium salt to pure PP13TFSI, the decomposition of more TFSI− anions possibly is a new reason for the increased sharply interfacial resistance. By contrast, the hybrid electrolytes with 50–70 wt% alkyl-carbonate co-solvents have advantages of high ionic conductivity and excellent thermal safety combined. Another even more important is that, due to theirs low viscosity and assistant CMB passivation, they have the superiorities in Li+ mobility, particle wettability and solid electrolyte interphase (SEI) film etc., and then show the improved charge–discharge performances. These results clearly prove the advantage of the use of hybrid electrolytes on the performance of the CMB electrode
Journal
[en] The measuring accuracy of magnetic probes is greatly improved by eliminating the disturbance of TF coils through a new discharge scenario, together with a careful calibration process. The measuring accuracy of flux loop is also improved by removing the clamping diodes in integrator which cause the loss of fast information. With accurate magnetic field and flux information input, the iteration and fitting process of EFIT converges quickly and outputs reliable results, which are consistent with diagnostic results achieved by Langmuir probes, Hα array and CCD image. A new self-developed plasma equilibrium reconstruction code, called sFIT, is also introduced, which outputs the plasma shape information that agrees very well with that of EFIT. (authors)
Journal
Nuclear Fusion and Plasma Physics; ISSN 0254-6086; ; v. 36(3); p. 193-198
; v. 36(3); p. 193-198
[en] The Nd13Fe79Ga1B7 alloy powders were treated by the HDDR process under different reduced hydrogen pressures in the range 0.2-0.8 bar, and the effects of the reduced hydrogen pressure on magnetic properties of the HDDR-treated alloy powders were investigated. It was found that the HDDR-treated alloy powders exhibit a considerable anisotropy in addition to an appropriate coercivity. As the reduced hydrogen pressure is lowered, the degree of anisotropy decreases significantly, whereas the intrinsic coercivity increases. The largest anisotropy of up to 1.62 is achieved in the powders HDDR-treated under a reduced hydrogen pressure of 0.8 bar, and the highest coercivity of 724 kAm-1 is attained in the powders HDDR-treated under 0.4 bar. (orig.)
Journal
[en] The oxidation of permalloys is important to apply in a wide range. The oxidation and diffusion mechanisms of small permalloy particles with different Fe content are studied by using thermal gravimetric analysis (TGA) and microstructure characterizations. Fe2O3/(Ni, Fe)3O4 plays a key role in the morphology evolution and diffusion mechanisms of small NiFe particles upon oxidation. The activation energies of grain boundary diffusion for the NiFe alloys increase from 141 kJ/mol to 208 kJ/mol as the Fe content increases from 0 to ~50 wt%. We have developed a diffusion process resolved temperature programed oxidation (PR-TPO) analysis method. Three diffusion mechanisms have been recognized by using this method: In addition to the grain boundary diffusion and lattice diffusion, our TGA analysis suggests that the phase conversion from Fe2O3 to (Ni, Fe)3O4 induces diffusion change and affects the diffusion process at the intermediate temperature. Relevant oxidation kinetics and diffusion mechanisms are discussed. - Graphical abstract: The oxidation mechanisms of small Permalloy particles with different Fe content is studied by using thermal gravimetric analysis (TGA) and microstructure characterizations. The activation energies of grain boundary diffusion for the NiFe alloys increases from 140 kJ/mol to 208 kJ/mol as the Fe content increases from 0 to 50 wt% as determined by TGA. We have developed a diffusion process resolved temperature programed oxidation (DPR-TPO) analysis method, and three diffusion mechanisms have been recognized by using this method: In addition to the well-known grain boundary diffusion and lattice diffusion, we found that the phase conversion from Fe2O3 to (Ni, Fe)3O4 will induce diffusion changes and affect the diffusion process at the intermediate temperature. The diffusion processes can be characterized by the corresponding characteristic peak temperatures in temperature programmed oxidation (TPO) analysis. This work not only give insight knowledge about the oxidation and diffusion processes of small permalloy particles, but also, provides a useful tool for analyzing solid-gas reactions of other materials. - Highlights: • The oxidation kinetics of small NiFe particles were studied by using thermoanalysis. • Grain boundary, lattice, and phase conversion induced diffusions were recognized. • The activation energy of oxidation increases with the Fe content in the alloy. • Each diffusion process corresponds to a characteristic temperature in TPO analysis. • NiFe alloys with ~5–10 wt% Fe content have the lowest oxidation rates.
Journal
[en] Highlights: • A HCPEB facility was introduced to perform the transient high heat load test. • APS submicron W coating, APS micron W coating and CVD-W coating were tested. • The behavior of three kinds of W coatings under transient high heat load was investigated. - Abstract: Three kinds of tungsten coatings are fabricated by means of APS and CVD, and evaluated by transient high heat load tests by 25 high-intensity current pulsed electron beam pulses with a duration of 0.2 ms and power densities of 0.4, 0.6 and 0.8 GW/m2. Remelting and solidification are found on post-test APS-W coating. However, cracks are developed for the same power densities for the CVD-W coating. APS-W coatings have about 20 times mass loss of CVD-W coating. The mass loss is related to the peak surface temperature of the APS-W coating exceeding the tungsten melting point (3410 °C) during electron beam irradiation. The CVD-W coating during testing was only 1000 °C
Journal
[en] Main function of discharge management platform for HL-2M tokamak is to provide a platform for operator to run timing system, PLC logic protect system and plasma feedback control system. During discharge interval, the operator uses it to preset the control parameters and waveforms for the next shot, to configure the operation parameters for all subsystems. The communication way based on reflective memory (RFM) is responsible for transmitting the control parameters and waveforms to all subsystems effectively and reliably. The results of commissioning between our platform and other subsystem shows that its design is reasonable, and its operation is reliable. (authors)
Journal
Nuclear Fusion and Plasma Physics; ISSN 0254-6086; ; v. 31(4); p. 339-343
; v. 31(4); p. 339-343
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