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A novel tetragonal B2CO structure (tP16-B2CO), formed by strong covalent sp2–sp3 B–C and B–O bonds, was predicted with aid of an unbiased structure searching method. With the energy lower than those of previously proposed candidates, except oI16-B2CO, tP16-B2CO was identified as the thermodynamic metastable phase for B2CO compound. The elastic matrix and phonon dispersion spectra declare that tP16-B2CO is mechanically and dynamically stable. The electronic band structure calculation at ambient pressure and a series of high pressure has manifested the indirect semiconducting and band gap increases first and then decreases with pressure increases. The calculation of mechanical properties such as hardness and stress–strain relations of tP16 structure revealed its common hard nature with high hardness of 23.19 GPa and anisotropy with the max stress along  is far higher than that along .
(1 − x)Ba(Mg1/3Ta2/3)O3–xBa(Co1/3Nb2/3)O3 (BMT–BCN, x = 0.0, 0.20, 0.25, 0.30, 0.40) ceramics were prepared using the traditional solid-state reaction method. X-ray diffraction patterns have shown that the intensities of (001) and (100) super-lattices decrease with the increase in the BCN content. Seven main Raman vibrational modes are observed, assigned, and illustrated, in particular. Raman shifts of Eg(O) modes and the FWHM values of F2g(O)/A1g(O) modes have close relationship with the dielectric properties. The calculated values by the four-parameter semiquantum model based on IR reflectivity match well with the measured data (@3.8 GHz), which means that most of dielectric contribution to the system may be ascribed to the absorption of structural phononic oscillations at the infrared region, and the contribution from the scattering of the defective phonons is small. The contributions of each vibrational mode on the dielectric responses were investigated in detail, indicating that the low-frequency modes (A2u(1) and Eu(1)) have a decisive role to the dielectric properties.
The present paper numerically prices a resettable guarantee of a salary-connected individual pension account (IPA). The results indicate that a principal guarantee without a reset feature is not worth much unless the volatility of assets in the IPA is huge, while the death benefit contributes a very small proportion to the guarantee value. Deferred proportional funding is an alternative to reducing problems from the difficulty in modeling salary behavior, because the required deferred proportional cost is impacted less by the salary behavior. Moreover, if the lapse from a guarantee is possible, then the guarantee is not necessarily more valuable for a younger individual.
Since the pioneer work by Bender and Boettcher on non-Hermitian Hamiltonian under paritytime (PT) symmetry [Phys. Rev. Lett. 80, 5243 (1998)], PT-symmetry optical coupled systems have been investigated extensively. Here we propose theoretically perfect transparency of a PT-symmetric acoustic coupled system which is comprised of a waveguide channel and two same-sized side-coupled resonators. Specifically, we demonstrate that with the change in the amplitude of attenuation and amplification coefficient, the spatial symmetry of two resonators is spontaneously broken which triggers an acoustic analog of electromagnetically induced transparency (EIT) by assigning anti-phase to the pressure field inside the two resonators.
High dietary intake of fats has been thought to be one of the major risk factors for the development of CVD. Less is known about the possible influence of fats from various sources on haemorheological abnormalities, which are considered an important factor in the pathogenesis of these diseases. The goal of the present study was to investigate effects of high-fat diets enriched in unsaturated fatty acids (USFA), SFA or trans-fatty acids (TFA), respectively, on haemorheological parameters in rats. Wistar female rats were divided into four groups and fed diets based on the AIN-93M formulation containing approximately 10 % energy from soyabean oil (control group) or 40 % energy from soyabean oil (USFA), palm oil (SFA) and vegetable shortening (TFA) for 8 weeks. The results showed that rats fed high-fat diets exhibited significant increases in serum TAG levels (P < 0·01), plasma viscosity (P < 0·01), whole blood viscosity (P < 0·01) and internal viscosity (P < 0·01) compared to the controls. The TFA group showed a significant decrease in erythrocyte deformability (P < 0·01) and increase in internal viscosity (P < 0·01) compared with the other groups. In addition, a significant increase in blood levels of free radicals (P < 0·01) was found in the TFA group, suggesting that the attack of oxygen-free radicals could be responsible for the impaired erythrocyte deformability. These impairments could be partly responsible for the development of various circulatory disorders. The present haemorheological study provides additional insights into the potential adverse effects of trans-fat and high-fat diets on haemorheological parameters.
It is well known that noctuid moths respond to ultrasound frequencies produced by insectivorous bats performing a series of evasive maneuvers such as loops, dives, rolls, and turns. Certain ultrasound frequencies may be considered an environmental stress factor for these moths, causing physiological and behavioral effects. We investigated changes in acetylcholinesterase activity of Helicoverpa armigera (Hübner) exposed to ultrasound produced from a commercial device (LHC20). Our results indicated that stress effects on acetylcholinesterase activity resulting from exposure to ultrasound do not differ according to sex, but effects on different developmental stages of H. armigera differ significantly depending on duration of exposure. Enzyme activity increased in adults after 20 min exposure to ultrasound and decreased in pupae after 30 and 50 min exposure. Enzyme activity in larvae was reduced after 20 min and increased after 40 and 60 min. The results of this study also indicate that stress caused by exposure to ultrasound could modulate the cholinergic system in H. armigera.