Ground state pairing correlations in the S4S_4 symmetric microscopic model for iron-based superconductors

We present the ground state pairing correlations in the $S_4$ symmetric microscopic model for iron-based superconductors, computed with the constrained-path Monte Carlo method. For various electron fillings and interaction strengths, we find that the $s_{xy}$ pairing dominates over other pairing correlations and is positive when the pair separation exceeds several lattice constants, whatever for iron pnictides and iron chlcogenides. These ground state properties, especially the long range part pairing correlations re-confirm the previous finite temperature results published in Phys. Rev. Lett. 110, 107002(2013). We further our study by including the nearest neighbour interaction $V$ and it is found that the $s_{xy}$ pairing correlation is slightly suppressed by the increasing $V$.Comment: 5 pages, 5 figures. arXiv admin note: text overlap with arXiv:1202.5881 by other author

Optimization of Culture Medium Enhances Viable Biomass Production and Biocontrol Efficacy of the Antagonistic Yeast, Candida diversa

Viable biomass production is a key determinant of suitability of antagonistic yeasts as potential biocontrol agents. This study investigated the effects of three metal ions (magnesium, ferrous, and zinc) on biomass production and viability of the antagonistic yeast, Candida diversa. Using response surface methodology to optimize medium components, a maximum biomass was obtained, when the collective Mg2+, Fe2+, and Zn2+ concentrations were adjusted in a minimal mineral (MM) medium. Compared with the unmodified MM, and three ion-deficient MM media, yeast cells cultured in the three ion-modified MM medium exhibited a lower level of cellular oxidative damage, and a higher level of antioxidant enzyme activity. A biocontrol assay indicated that C. diversa grown in the ion-modified MM exhibited the greatest level of control of gray mold on apple fruit. These results provide new information on culture medium optimization to grow yeast antagonists in order to improve biomass production and biocontrol efficacy

Quantum Monte Carlo study of the

The S4 symmetric microscopic model with two iso-spin components has been studied via constrained-path quantum Monte Carlo simulation. Our results demonstrate a stable (π, 0) or (0, π) magnetic order which is significantly enhanced on increasing both the Coulomb repulsion U and Hund’s coupling strength J. Also, our simulation indicates that the magnetic order tends to be in an orthomagnetic state, in which the nearest-neighbour magnetic moment are orthogonal to each other, rather than in a collinear antiferromagnetic order. Interestingly, when the system is doped away from half filling, the magnetic order is obviously elevated in the low doping density, and then significantly suppressed when more electrons are introduced. Meanwhile, we find that an A1g s±-wave pairing dominates all the singlet nearest-neighbour pairings, and is significantly enhanced by electron doping

An arbitrary waveform synthesis structure with high sampling rate and low spurious

The arbitrary waveform generator is characterised by its flexible signal generation, high frequency resolution and rapid frequency switching speed and is wildly used in fields like communication, radar systems, quantum control, astronautics and biomedicine. With continuous development of technology, higher requirements are placed on to the arbitrary waveform generator. Sampling rate determines the bandwidth of the output signal, spurious-free dynamic range determines the quality of generated signal. Due to above, these two indicators’ improvement is vital. However, the existing waveform generation methods cannot generate signals with quality good enough due to their technical limitations, and in order to realize a high system sampling rate, to accomplish waveform generation process in FPGA, multipath parallel structure is needed. Therefore, we proposed a parallel waveform synthesis structure based on digital resampling, which fixed the problems existing in the current methods effectively and achieved a high sampling rate as well as high quality arbitrary waveform synthesis. We also built up an experimental test bench to validate the proposed structure

Enhanced Thermoelectric Properties of Cu3SbSe3-Based Composites with Inclusion Phases

Cu3SbSe3-based composites have been prepared by self-propagating high-temperature synthesis (SHS) combined with spark plasma sintering (SPS) technology. Phase composition and microstructure analysis indicate that the obtained samples are mainly composed of Cu3SbSe3 phase and CuSbSe2/Cu2−xSe secondary phases. Our results show that the existence of Cu2−xSe phase can clearly enhance the electrical conductivity of the composites (~16 S/cm), which is 2.5 times higher than the pure phase. The thermal conductivity can remain at about 0.30 W·m−1·K−1 at 653 K. A maximum ZT (defined as ZT = S2σΤ/κ, where S, σ, Τ, κ are the Seebeck coefficient, electrical conductivity, absolute temperature and total thermal conductivity) of the sample SPS 633 can be 0.42 at 653 K, which is 60% higher than the previously reported values. Our results indicate that the composite structure is an effective method to enhance the performance of Cu3SbSe3