Electronic Structures of Antiperovskite Superconductor MgCNi3_3 and Related Compounds

Electronic structure of a newly discovered antiperovskite superconductor MgCNi$_3$ is investigated by using the LMTO band method. The main contribution to the density of states (DOS) at the Fermi energy $E_{\rm F}$ comes from Ni 3$d$ states which are hybridized with C 2$p$ states. The DOS at $E_{\rm F}$ is varied substantially by the hole or electron doping due to the very high and narrow DOS peak located just below $E_{\rm F}$. We have also explored electronic structures of C-site and Mg-site doped MgCNi$_3$ systems, and described the superconductivity in terms of the conventional phonon mechanism.Comment: 3 pages, presented at ORBITAL2001 September 11-14, 2001 (Sendai, JAPAN

Electronic structures of antiperovskite superconductors: MgXNi3_3 (X=B,C,N)

We have investigated electronic structures of a newly discovered antiperovskite superconductor MgCNi$_3$ and related compounds MgBNi$_3$ and MgNNi$_3$. In MgCNi$_3$, a peak of very narrow and high density of states is located just below $\rm E_F$, which corresponds to the $\pi^*$ antibonding state of Ni-3d and C-$2p$ but with the predominant Ni-3d character. The prominent nesting feature is observed in the $\Gamma$-centered electron Fermi surface of an octahedron-cage-like shape that originates from the 19th band. The estimated superconducting parameters based on the simple rigid-ion approximation are in reasonable agreement with experiment, suggesting that the superconductivity in MgCNi$_3$ is described well by the conventional phonon mechanism.Comment: 5 pages, 5 figure

Initial-boundary value problems for conservation laws with source terms and the Degasperis-Procesi equation

We consider conservation laws with source terms in a bounded domain with Dirichlet boundary conditions. We first prove the existence of a strong trace at the boundary in order to provide a simple formulation of the entropy boundary condition. Equipped with this formulation, we go on to establish the well-posedness of entropy solutions to the initial-boundary value problem. The proof utilizes the kinetic formulation and the compensated compactness method. Finally, we make use of these results to demonstrate the well-posedness in a class of discontinuous solutions to the initial-boundary value problem for the Degasperis-Procesi shallow water equation, which is a third order nonlinear dispersive equation that can be rewritten in the form of a nonlinear conservation law with a nonlocal source term.Comment: 24 page

Electronic structure of metallic antiperovskite compound GaCMn3_3

We have investigated electronic structures of antiperovskite GaCMn$_3$ and related Mn compounds SnCMn$_3$, ZnCMn$_3$, and ZnNMn$_3$. In the paramagnetic state of GaCMn$_3$, the Fermi surface nesting feature along the $\Gamma{\rm R}$ direction is observed, which induces the antiferromagnetic (AFM) spin ordering with the nesting vector {\bf Q} $\sim \Gamma{\rm R}$. Calculated susceptibilities confirm the nesting scenario for GaCMn$_3$ and also explain various magnetic structures of other antiperovskite compounds. Through the band folding effect, the AFM phase of GaCMn$_3$ is stabilized. Nearly equal densities of states at the Fermi level in the ferromagnetic and AFM phases of GaCMn$_3$ indicate that two phases are competing in the ground state.Comment: 4 pages, 5 figure

Strategies for replacing saturated fat in meat products: A review

This paper aims to provide a better understanding of how to replace saturated fat in meat products due to concerns about its high amounts as health consciousness improves and consumers look for changes. In particular, we focused on various approaches and technologies to replace saturated fat in meat products. A systematic literature review was conducted using Web of Science, Google Scholar, and Scopus based on existing papers. The use of vegetable oils in meat products, oleogel and emulsion gel technologies, as well as application of protein substitutes were reviewed. The results show that the mentioned methods are potentially effective techniques for reducing the saturated fat content of meat products. As research on new approaches to fat substitutes continues to attract interest, we would like to highlight the research needs for the development of healthy meat products in the long term.This paper aims to provide a better understanding of how to replace saturated fat in meat products due to concerns about its high amounts as health consciousness improves and consumers look for changes. In particular, we focused on various approaches and technologies to replace saturated fat in meat products. A systematic literature review was conducted using Web of Science, Google Scholar, and Scopus based on existing papers. The use of vegetable oils in meat products, oleogel and emulsion gel technologies, as well as application of protein substitutes were reviewed. The results show that the mentioned methods are potentially effective techniques for reducing the saturated fat content of meat products. As research on new approaches to fat substitutes continues to attract interest, we would like to highlight the research needs for the development of healthy meat products in the long term

Electronic structures of doped anatase TiO2\rm TiO_{2}: Ti1−xMxO2\rm Ti_{1-x}M_{x}O_{2} (M=Co, Mn, Fe, Ni)

We have investigated electronic structures of a room temperature diluted magnetic semiconductor : Co-doped anatase $\rm TiO_{2}$. We have obtained the half-metallic ground state in the local-spin-density approximation(LSDA) but the insulating ground state in the LSDA+$U$+SO incorporating the spin-orbit interaction. In the stoichiometric case, the low spin state of Co is realized with the substantially large orbital moment. However, in the presence of oxygen vacancies near Co, the spin state of Co becomes intermediate. The ferromagnetisms in the metallic and insulating phases are accounted for by the double-exchange-like and the superexchange mechanism, respectively. Further, the magnetic ground states are obtained for Mn and Fe doped $\rm TiO_{2}$, while the paramagnetic ground state for Ni-doped $\rm TiO_{2}$.Comment: 5 pages, 4 figure

Similarity of operators and geometry of eigenvector bundles

We characterize the contractions that are similar to the backward shift in the Hardy space H². This characterization is given in terms of the geometry of the eigenvector bundles of the operators

Relation between Kitaev magnetism and structure in α\alpha-RuCl3_3

Raman scattering has been employed to investigate lattice and magnetic excitations of the honeycomb Kitaev material $\alpha$-RuCl$_3$ and its Heisenberg counterpart CrCl$_3$. Our phonon Raman spectra give evidence for a first-order structural transition from a monoclinic to a rhombohedral structure for both compounds. Significantly, only $\alpha$-RuCl$_3$ features a large thermal hysteresis, consistent with the formation of a wide phase of coexistence. In the related temperature interval of $70-170$ K, we observe a hysteretic behavior of magnetic excitations as well. The stronger magnetic response in the rhombohedral compared to the monoclinic phase evidences a coupling between the crystallographic structure and low-energy magnetic response. Our results demonstrate that the Kitaev magnetism concomitant with fractionalized excitations is susceptible to small variations of bonding geometry.Comment: 9 pages, 8 figures, To appear in PR

Microalgae as alternative proteins for the sustainable food industry: A review

This paper reviews the nutritional properties and consumer perceptions of microalgae foods through various recent studies on alternative protein sources. Food choices, including meat consumption, are a common concern for humanity. Thus, we focused on whether microalgae foods have a sufficient value as a protein source and what nutritional benefits they have. Based on existing papers, we conducted a systematic review using Web of Science, Google Scholar, and Scopus to comprehensively investigate and summarize the nutritional characteristics of microalgae, sustainable diets, and awareness of microalgae as an alternative protein source. Research has shown that microalgae have been consumed by humans as a protein source since ancient times, and contain enough protein to be used as an alternative protein source. They also have many other nutritional benefits, such as vitamins. We have found that consumers are increasingly interested in alternative protein sources, and the more they learn about microalgae, the more accepting they become. These results may suggest a need for further research to improve microalgae as an alternative protein source in the long run and develop them into a variety of foods

Extending Romanovski polynomials in quantum mechanics

Some extensions of the (third-class) Romanovski polynomials (also called Romanovski/pseudo-Jacobi polynomials), which appear in bound-state wavefunctions of rationally-extended Scarf II and Rosen-Morse I potentials, are considered. For the former potentials, the generalized polynomials satisfy a finite orthogonality relation, while for the latter an infinite set of relations among polynomials with degree-dependent parameters is obtained. Both types of relations are counterparts of those known for conventional polynomials. In the absence of any direct information on the zeros of the Romanovski polynomials present in denominators, the regularity of the constructed potentials is checked by taking advantage of the disconjugacy properties of second-order differential equations of Schr\"odinger type. It is also shown that on going from Scarf I to Scarf II or from Rosen-Morse II to Rosen-Morse I potentials, the variety of rational extensions is narrowed down from types I, II, and III to type III only.Comment: 25 pages, no figure, small changes, 3 additional references, published versio