The magnetism for NN AFM ground state in Fe-based superconductor: Sr1−xKxFe2As2

The crystal structure, magnetism properties, and density of states for FeAs layered compound SrFe₂As₂ have been investigated by using the density functional theory (DFT) method. The magnetism under a checkerboard nearest neighbor anti-ferromagnetic (NN AFM) and ferromagnetic (FM) order ground-state have been analyzed with substitution for Sr with K ion in Sr_1−xK_xFe₂As₂. The results indicate that the distortion of FeAs tetrahedrons is sensitive to the electron doping concentration. The system magnetism was suppressed by K doping in NN-AFM ground state instead of FM. The density of states at Fermi level N(E_F) under NN AFM ground state would be regarded as a driving force for the increased T_c of Sr_1−xK_xFe₂As₂ system as observed experimentally. Our calculation reflects that NN AFM type spin fluctuation may still exist in the Sr_1−xK_xFe₂As₂ system and it may be an origin of strong spin fluctuation in this system besides the spin density wave (SDW) states.     

Sonodynamically induced anti-tumor effect with protoporphyrin IX on hepatoma-22 solid tumor

Objective

The purpose of this study was to evaluate sonodynamically induced anti-tumor effect of protoporphyrin IX (PPIX) in mice bearing hepatoma-22 (H-22) solid tumors, and the possible in vivo cell damage mechanism was also investigated.

Methods

The pharmacokinetics of PPIX was analyzed in plasma, skin, muscle and tumor of H-22 bearing mice. Tumors were irradiated with ultrasound (1.43 MHz, I_SATA 3 W/cm², 3 min) for three times at 8, 12 and 24 h after 5.0 mg/kg PPIX administration, respectively. The anti-tumor effects of sonodynamic therapy (SDT) were estimated by the tumor inhibition ratio (volume and weight). The bio-effects of SDT were evaluated by hematoxylin and eosin (H&E) staining, transmission electron microscope (TEM) observation, lipid peroxidation (LPO) measurement and anti-oxidative enzymes (glutathione peroxidase (GSH-PX), catalase (CAT) and superoxide dismutase (SOD)) assay.

Results

A significant anti-tumor effect was obtained by PPIX-mediated sonodynamic therapy (PPIX-SDT). At the fifteenth day after PPIX-SDT, the tumor growth and tumor weight inhibition ratios were 53.84% and 45.86%, respectively. In addition, the structure of tumor tissues and the anti-oxidative enzymes were obviously destroyed after SDT treatment.

Conclusions

A biochemical mechanism was involved in PPIX-SDT in vivo, and the free radicals produced by the synergistic treatment destroying the anti-oxidative system of tumor cells in vivo may play an important role in this action. Also, the thermal effect could not be excluded in inducing damage of cellular structures, like membrane disruption and chromatin condensation under current evaluation in this paper.     

High spatial resolution distributed strain sensor based on linear chirped fiber Bragg grating and fiber loop ringdown spectroscopy

A simple sensor system for high spatial resolution distributed strain field measurement is proposed and demonstrated experimentally. The fiber loop ringdown technique combined with a linear chirped fiber Bragg grating is used to realize the high spatial resolution. A proof-of-concept distributed strain sensor with 2?mm spatial resolution is realized. The sensor network is also explored and researched experimentally. The proposed technique suggests a broad range of applications for real-time distributed physical parameter sensing, such as strain or temperature.     

Scattering-induced changes in the temporal coherence length and the pulse duration of a partially coherent plane-wave pulse

The scattering of a partially coherent plane-wave pulse on a Gaussian-correlated, quasi-homogeneous random medium is investigated. The analytical expressions for the temporal coherence length and the pulse duration of the scattered field are derived. We demonstrate that the scattering-induced changes in the temporal coherence length and the pulse duration may be used to determine the correlation function of the scattering potential of the medium.     

Evolution of Zn based high purity phases under NH3 gas atmosphere and their PL properties

We report here the evolution of zinc based high purity phases with novel morphologies such as Zn₃N₂ hollow structures, ZnO nanowires and nanopowders, as well as metallic Zn layered hexagonal microparticles at progressively increased reaction temperature of 600 °C, 700 °C, 800 °C under NH₃ gas atmosphere using Zn powder precursor and keeping all other experimental parameters unchanged. Growth mechanism for Zn₃N₂ obtained by nitridation, ZnO by oxidation and Zn microparticles via thermal evaporation & condensation process are discussed briefly. The as-synthesized products were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM). Photoluminescence (PL) studies have revealed very interesting and infrequently observed emission bands at 378 and 661 nm for Zn₃N₂, 359 and 396 nm for ZnO as well as 389 nm for Zn polyhedral microparticles.     

Piezoelectric coefficients of cross-linked polypropylene films stretched at elevated temperatures

Cross-linked polypropylene (XPP) foams are modified by a hot-stretching process and charged to be piezoelectric. The results show that a piezoelectric d₃₃ -coefficient of 308pC/N is obtained for sample with an elongation ratio of 200%. The dynamic d₃₃ value is smaller than the quasi-static value, which is probably due to the rise of Young’s modulus with increasing frequency. All the samples show pressure-independent d₃₃ in the range up to 30 kPa. Improved d₃₃ was obtained in the sample rough surface exposed to the corona during charging. Compared to linear PP, the stretched XPP shows pressure independence of d₃₃ in larger range.     

Ballistic phonon transport through a Fibonacci array of acoustic nanocavities in a narrow constriction

We investigate the ballistic phonon transport through a Fibonacci array of acoustic nanocavities in a narrow constriction of a semiconductor nanowire at low temperatures. It is found that the transmission spectrum of such a system consists of quasiband gaps and narrow resonances caused by the coupling of phonon waves. Both phonon transmission and thermal conductance exhibit the similarity due to the Fibonacci sequence structure. The similarity is sensitive to the number n and parameters of nanocavities. The results are compared with those in a periodic acoustic nanocavities.     

A discrete artificial bee colony algorithm for the multi-objective flexible job-shop scheduling problem with maintenance activities

This paper presents a novel discrete artificial bee colony (DABC) algorithm for solving the multi-objective flexible job shop scheduling problem with maintenance activities. Performance criteria considered are the maximum completion time so called makespan, the total workload of machines and the workload of the critical machine. Unlike the original ABC algorithm, the proposed DABC algorithm presents a unique solution representation where a food source is represented by two discrete vectors and tabu search (TS) is applied to each food source to generate neighboring food sources for the employed bees, onlooker bees, and scout bees. An efficient initialization scheme is introduced to construct the initial population with a certain level of quality and diversity. A self-adaptive strategy is adopted to enable the DABC algorithm with learning ability for producing neighboring solutions in different promising regions whereas an external Pareto archive set is designed to record the non-dominated solutions found so far. Furthermore, a novel decoding method is also presented to tackle maintenance activities in schedules generated. The proposed DABC algorithm is tested on a set of the well-known benchmark instances from the existing literature. Through a detailed analysis of experimental results, the highly effective and efficient performance of the proposed DABC algorithm is shown against the best performing algorithms from the literature.     

The \mathfrak {sl}_{3}-web algebra

In this paper we use Kuperberg’s $\mathfrak {sl}_3$ -webs and Khovanov’s $\mathfrak {sl}_3$ -foams to define a new algebra $K^S$ , which we call the $\mathfrak {sl}_3$ -web algebra. It is the $\mathfrak {sl}_3$ analogue of Khovanov’s arc algebra. We prove that $K^S$ is a graded symmetric Frobenius algebra. Furthermore, we categorify an instance of $q$ -skew Howe duality, which allows us to prove that $K^S$ is Morita equivalent to a certain cyclotomic KLR-algebra of level 3. This allows us to determine the split Grothendieck group $K^{\oplus }_0(\mathcal {W}^S)_{\mathbb {Q}(q)}$ , to show that its center is isomorphic to the cohomology ring of a certain Spaltenstein variety, and to prove that $K^S$ is a graded cellular algebra.