A series of YTi(Fe_(1-x)_(11)alloy with x=0.00,0.01,0.03,0.04,0.05,0.07 and 0.10 has been investigated by measurement of the structural properties and ^(57)Fe M(?)ssbauer experiments.The pure ThMn_(12)-structure phase...A series of YTi(Fe_(1-x)_(11)alloy with x=0.00,0.01,0.03,0.04,0.05,0.07 and 0.10 has been investigated by measurement of the structural properties and ^(57)Fe M(?)ssbauer experiments.The pure ThMn_(12)-structure phase exists at x≤0.03 and is absent at x>0.03.The reasons for lower satura- tion magnetization and lower energy product of the ThMn_(12)-structure compounds were given.The crystal structure relations between R_2Fe_(17)-structure and ThMn_(12)-structure were discussed.Comparing with the R_2Fe_(17)and R_2Fe_(14)B compounds,the ThMn_(12)-structure RFe_(12-x)M_x compounds have the same magnetic moment of Fe at x=0.The potential for increasing the saturation magnetization of ThMn_(12)-structure compounds may be enhanced by the addition of stabilization elements.展开更多
In general,ordered algebraic structures,particularly ordered semigroups,play an important role in fuzzification in many applied areas,such as computer science,formal languages,coding theory,error correction,etc.Nowada...In general,ordered algebraic structures,particularly ordered semigroups,play an important role in fuzzification in many applied areas,such as computer science,formal languages,coding theory,error correction,etc.Nowadays,the concept of ambiguity is important in dealing with a variety of issues related to engineering modeling problems,network theory,decision-making problems in real-life situations,and so on.Several theories have been developed by various researchers to overcome the difficulties that arise from uncertainty,including fuzzy sets,intuitionistic fuzzy sets,probability,softsets,neutrosophic sets,andmanymore.Inthispaper,we focus solelyonneutrosophic set theory.In ordered semigroups,we define and investigate the properties of neutrosophicκ-ideals and neutrosophicκ-interior ideals.We also use neutrosophicκ-ideals and neutrosophicκ-interior ideals to characterize ordered semigroups.展开更多
We consider a parametrized family of compact G2-calibrated solvmanifolds, and construct associative (so volume-minimizing submanifolds) 3-tori with respect to the closed G2-structure. We also study the Laplacian flow ...We consider a parametrized family of compact G2-calibrated solvmanifolds, and construct associative (so volume-minimizing submanifolds) 3-tori with respect to the closed G2-structure. We also study the Laplacian flow of this closed G2 form on the solvable Lie group underlying to each of these solvmanifolds, and show long time existence of the solution.展开更多
The realization of 100%polarized topologicalWeyl fermions in half-metallic ferromagnets is of particular importance for fundamental research and spintronic applications.Here,we theoretically investigate the electronic...The realization of 100%polarized topologicalWeyl fermions in half-metallic ferromagnets is of particular importance for fundamental research and spintronic applications.Here,we theoretically investigate the electronic and topological properties of the zinc-blende compound VAs,which was deemed as a half-metallic ferromagnet related to dynamic correlations.Based on the combination of density functional theory and dynamical mean field theory,we uncover that the half-metallic ferromagnet VAs exhibits attractive Weyl semimetallic behaviors which are very close to the Fermi level in the DFT+U regime with effect U values ranging from 1.5 eV to 2.5 eV.Meanwhile,we also investigate the magnetization-dependent topological properties;the results show that the change of magnetization directions only slightly affects the positions of Weyl points,which is attributed to the weak spin–orbital coupling effects.The topological surface states of VAs projected on semi-infinite(001)and(111)surfaces are investigated.The Fermi arcs of all Weyl points are clearly visible on the projected Fermi surfaces.Our findings suggest that VAs is a fully spin-polarized Weyl semimetal with many-body correlated effects in the effective U values range from 1.5 eV to 2.5 eV.展开更多
Half-Heusler(HH)合金由于其本身具有较为优异的力学性能和高温热稳定性,已成为目前最具有应用前景的中高温热电材料之一。然而,其本身较高的本征晶格热导率阻碍了热电性能的进一步提升。本文以P型Zr Co Sb0.85Sn0.15合金为研究对象,基...Half-Heusler(HH)合金由于其本身具有较为优异的力学性能和高温热稳定性,已成为目前最具有应用前景的中高温热电材料之一。然而,其本身较高的本征晶格热导率阻碍了热电性能的进一步提升。本文以P型Zr Co Sb0.85Sn0.15合金为研究对象,基于同构合金化具有优异P型热电性能的(Nb0.8Ta0.2)0.8Ti0.2Fe Sb,通过磁悬浮熔炼和放电等离子烧结设计并制备出一种(Zr Co Sb0.85Sn0.15)1-x[(Nb0.8Ta0.2)0.8Ti0.2Fe Sb]x(x=0,0.2,0.3,0.4,0.5)高熵HH合金。微观组织分析表明,同构合金化这一策略引入了大量多尺度多衬度的第二相,这将有效增强对声子的散射。其中,当同构合金化含量为0.3时,晶格热导率在923 K时从Zr Co Sb0.85Sn0.15的4.72 W·m-1·K-1降至3.07 W·m-1·K-1,降低了35%。然而,由于多位点合金化元素间存在较为复杂的掺杂效果,使其电导率和塞贝克系数同时降低,最终导致热电优值存在一定的降低。本研究工作表明,高熵合金设计思想是一种降低HH热电合金晶格热导率的有力措施。展开更多
A highly efficient and re liable topology-dual buck half bridge inverter (DBI) is introduced. The existenc e of discontinuous conduction mode (DCM) operation state requires the bias of in du ctor current for DBI imple...A highly efficient and re liable topology-dual buck half bridge inverter (DBI) is introduced. The existenc e of discontinuous conduction mode (DCM) operation state requires the bias of in du ctor current for DBI implemented with linear controllers like ramp comparison SP WM (RCSPWM) controllers. A novel operation scheme for DBI and a hysteresis curre nt controlled dual buck half bridge inverter (HCDBI) are proposed. The bias curr ent required by RCSPWM DBI is eliminated and conduction losses are dramatically reduced. HCDBI has greatly improved the modulation performance in DCM region for the benefit of its excellent command tracking capability. The operational schem e and control strategy are presented. Power losses of the conventional half brid ge inverter (CHBI) and HCDBI are compared with mathematical computation, and exp erimental verification is also executed. Both calculational and experimental res ults verify that HCDBI has a superior switching performance over CHBI. Its exce llent high frequency operational capacity provides another access to realize high fre quency operation of inverters.展开更多
设计一种特别的TiCoSb复合靶材,通过调节各元素在复合靶材上所占面积的大小,可以方便地调节薄膜的成分.采用这种靶材,利用直流磁控溅射和快速退火成功制备单一物相的多晶TiCoSb薄膜;采用X射线衍射(X-raydiffraction,XRD)和原子力显微镜(...设计一种特别的TiCoSb复合靶材,通过调节各元素在复合靶材上所占面积的大小,可以方便地调节薄膜的成分.采用这种靶材,利用直流磁控溅射和快速退火成功制备单一物相的多晶TiCoSb薄膜;采用X射线衍射(X-raydiffraction,XRD)和原子力显微镜(atomic force microscopy,AFM)分析TiCoSb薄膜的结构和表面形貌;利用Hall测试仪初步研究薄膜的电学性质.结果表明,所制备的TiCoSb薄膜对石英玻璃衬底具有良好的粘附力,薄膜均匀致密.经600℃,5 min退火的TiCoSb薄膜的结晶质量较好,薄膜的室温电导率为13.7 S/cm.展开更多
文摘A series of YTi(Fe_(1-x)_(11)alloy with x=0.00,0.01,0.03,0.04,0.05,0.07 and 0.10 has been investigated by measurement of the structural properties and ^(57)Fe M(?)ssbauer experiments.The pure ThMn_(12)-structure phase exists at x≤0.03 and is absent at x>0.03.The reasons for lower satura- tion magnetization and lower energy product of the ThMn_(12)-structure compounds were given.The crystal structure relations between R_2Fe_(17)-structure and ThMn_(12)-structure were discussed.Comparing with the R_2Fe_(17)and R_2Fe_(14)B compounds,the ThMn_(12)-structure RFe_(12-x)M_x compounds have the same magnetic moment of Fe at x=0.The potential for increasing the saturation magnetization of ThMn_(12)-structure compounds may be enhanced by the addition of stabilization elements.
基金The authors are grateful to the anonymous referees for careful checking of the details and for helpful comments that improved this paper.This work was supported by the Taif University Researchers Supporting Project(TURSP-2020/246),Taif University,Taif,Saudi Arabia.
文摘In general,ordered algebraic structures,particularly ordered semigroups,play an important role in fuzzification in many applied areas,such as computer science,formal languages,coding theory,error correction,etc.Nowadays,the concept of ambiguity is important in dealing with a variety of issues related to engineering modeling problems,network theory,decision-making problems in real-life situations,and so on.Several theories have been developed by various researchers to overcome the difficulties that arise from uncertainty,including fuzzy sets,intuitionistic fuzzy sets,probability,softsets,neutrosophic sets,andmanymore.Inthispaper,we focus solelyonneutrosophic set theory.In ordered semigroups,we define and investigate the properties of neutrosophicκ-ideals and neutrosophicκ-interior ideals.We also use neutrosophicκ-ideals and neutrosophicκ-interior ideals to characterize ordered semigroups.
文摘We consider a parametrized family of compact G2-calibrated solvmanifolds, and construct associative (so volume-minimizing submanifolds) 3-tori with respect to the closed G2-structure. We also study the Laplacian flow of this closed G2 form on the solvable Lie group underlying to each of these solvmanifolds, and show long time existence of the solution.
基金the National Natural Science Foun-dation of China(Grant Nos.12204074,12222402,92365101,and 12347101)the Natural Science Foundation of Chong-ging(Grant No.CSTB2023NSCQ-JQX0024).
文摘The realization of 100%polarized topologicalWeyl fermions in half-metallic ferromagnets is of particular importance for fundamental research and spintronic applications.Here,we theoretically investigate the electronic and topological properties of the zinc-blende compound VAs,which was deemed as a half-metallic ferromagnet related to dynamic correlations.Based on the combination of density functional theory and dynamical mean field theory,we uncover that the half-metallic ferromagnet VAs exhibits attractive Weyl semimetallic behaviors which are very close to the Fermi level in the DFT+U regime with effect U values ranging from 1.5 eV to 2.5 eV.Meanwhile,we also investigate the magnetization-dependent topological properties;the results show that the change of magnetization directions only slightly affects the positions of Weyl points,which is attributed to the weak spin–orbital coupling effects.The topological surface states of VAs projected on semi-infinite(001)and(111)surfaces are investigated.The Fermi arcs of all Weyl points are clearly visible on the projected Fermi surfaces.Our findings suggest that VAs is a fully spin-polarized Weyl semimetal with many-body correlated effects in the effective U values range from 1.5 eV to 2.5 eV.
文摘Half-Heusler(HH)合金由于其本身具有较为优异的力学性能和高温热稳定性,已成为目前最具有应用前景的中高温热电材料之一。然而,其本身较高的本征晶格热导率阻碍了热电性能的进一步提升。本文以P型Zr Co Sb0.85Sn0.15合金为研究对象,基于同构合金化具有优异P型热电性能的(Nb0.8Ta0.2)0.8Ti0.2Fe Sb,通过磁悬浮熔炼和放电等离子烧结设计并制备出一种(Zr Co Sb0.85Sn0.15)1-x[(Nb0.8Ta0.2)0.8Ti0.2Fe Sb]x(x=0,0.2,0.3,0.4,0.5)高熵HH合金。微观组织分析表明,同构合金化这一策略引入了大量多尺度多衬度的第二相,这将有效增强对声子的散射。其中,当同构合金化含量为0.3时,晶格热导率在923 K时从Zr Co Sb0.85Sn0.15的4.72 W·m-1·K-1降至3.07 W·m-1·K-1,降低了35%。然而,由于多位点合金化元素间存在较为复杂的掺杂效果,使其电导率和塞贝克系数同时降低,最终导致热电优值存在一定的降低。本研究工作表明,高熵合金设计思想是一种降低HH热电合金晶格热导率的有力措施。
文摘A highly efficient and re liable topology-dual buck half bridge inverter (DBI) is introduced. The existenc e of discontinuous conduction mode (DCM) operation state requires the bias of in du ctor current for DBI implemented with linear controllers like ramp comparison SP WM (RCSPWM) controllers. A novel operation scheme for DBI and a hysteresis curre nt controlled dual buck half bridge inverter (HCDBI) are proposed. The bias curr ent required by RCSPWM DBI is eliminated and conduction losses are dramatically reduced. HCDBI has greatly improved the modulation performance in DCM region for the benefit of its excellent command tracking capability. The operational schem e and control strategy are presented. Power losses of the conventional half brid ge inverter (CHBI) and HCDBI are compared with mathematical computation, and exp erimental verification is also executed. Both calculational and experimental res ults verify that HCDBI has a superior switching performance over CHBI. Its exce llent high frequency operational capacity provides another access to realize high fre quency operation of inverters.
文摘设计一种特别的TiCoSb复合靶材,通过调节各元素在复合靶材上所占面积的大小,可以方便地调节薄膜的成分.采用这种靶材,利用直流磁控溅射和快速退火成功制备单一物相的多晶TiCoSb薄膜;采用X射线衍射(X-raydiffraction,XRD)和原子力显微镜(atomic force microscopy,AFM)分析TiCoSb薄膜的结构和表面形貌;利用Hall测试仪初步研究薄膜的电学性质.结果表明,所制备的TiCoSb薄膜对石英玻璃衬底具有良好的粘附力,薄膜均匀致密.经600℃,5 min退火的TiCoSb薄膜的结晶质量较好,薄膜的室温电导率为13.7 S/cm.