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Chalcogenides have been considered as promising thermoelectric materials because of their low cost, nontoxicity, and environmental benignity. In this work, we synthesized a series of Cu2S1–xTex(0 ≤ x≤ 1) alloys by a facile, rapid method of mechanical alloying combined with spark plasma sintering process. The Cu2S1–xTexsystem provides an excellent vision of the competition between pure phase and phase transformation, entropy-driven solid solution, and enthalpy-driven phase separation. When the Te concentration increases, the Cu2S1–xTexsystem changed from the pure monoclinic Cu2S at x= 0 to monoclinic Cu2S1–xTexsolid solution at 0.02 ≤ x≤ 0.06 and then transforms to hexagonal Cu2S1–xTexsolid solution at 0.08 ≤ x≤ 0.1. The phase separation of hexagonal Cu2Te in the hexagonal Cu2S matrix occurs at 0.3 ≤ x≤ 0.7 and finally forms the hexagonal Cu2Te at x= 1. Owing to the changed band structure and the coexisted Cu2S and Cu2Te phases, greatly enhanced power factor was achieved in all Cu2S1–xTex(0 < x< 1) alloys. Meanwhile, the point defect introduced by the substitution of Te/S atoms strengthened the phonon scattering, resulting in a lowered lattice thermal conductivity in most of these solid solutions. As a consequence, Cu2S0.94Te0.06exhibits a maximum ZTvalue of 1.18 at 723 K, which is about 3.7 and 14.8 times as compared to the values of pristine Cu2S (0.32) and Cu2Te (0.08), respectively.

AbstractVaccination is the most effective and cost-effective way to treat hepatitis B virus (HBV) infection. Collective data suggest that helminth infections affect immune responses to some vaccines. Therefore, it is important to reveal the effects of helminth infections on the efficacy of protective vaccines in countries with highly prevalent helminth infections. In the present work, effects of Trichinella spiralisinfection on the protective efficacy of HBV vaccine in a mouse model were investigated. This study demonstrated that the enteric stage of T. spiralisinfection could inhibit the proliferative response of spleen lymphocytes to hepatitis B surface antigen (HBsAg) and lead to lower levels of anti-HBsAg antibodies, interferon-γ, and interleukin (IL)-2, along with higher levels of IL-4 and IL-5. However, these immunological differences are absent in the muscle stage of T. spiralisinfection. The results suggest that the muscle stage of T. spiralisinfection does not affect the immune response to HBV vaccination, while the enteric-stage infection results in a reduced immune response to HBsAg.

Developing high performance aero-engines usually depends on the development of new candidate materials with charming properties such as relatively light-weight, good high temperature strength and environmental resistance. Fortunately, γ-TiAl alloys were followed into this catalogue that they offer a significant potentiality for weight savings. Recently, in order to improve their low room temperature plasticity, a motive technology called electromagnetic cold crucible directional solidification technology for preparation γ-TiAl alloy ingots with directional growth structure was put forward by our group. By the approach, TiAl ingots with controllable lamellar structures and less impurity contaminations are obtained. Typically, Ti-46Al-0.5W-0.5Si and Ti-47Al-2Cr-2Nb were performed with respect to compositions and solidification parameters. As a result, Ti-46Al-0.5W-0.5Si DS-samples exhibit good combination of mechanical properties at room temperature in TS of 500MPa and EL of 2% in average. Meanwhile TS of DS Ti-47Al-2Cr-2Nb reaches 650 MPa and EL exceeds 3%.

It has been a grand challenge to develop efficient thermoelectric materials for room temperatureapplications. Here, motivated by the recent experimental synthesis of Sn2Bi sheet on silicon wafer [Phys. Rev. Lett.121, 126801 (2018)], for the first time we find that fluorination not only can stabilize Sn2Bi sheet in free-standing condition but also can significantly enhance the thermoelectric performance. The fluorinated Sn2Bi sheet exhibits an enlarged three-phonon scattering phase space, reduced group velocity and enhanced anharmonicity, leading to an ultralow lattice thermal conductivity of 0.19 W m−1 K−1and an ultrahigh ZT value of 2.45 (1.70) at 300 K for n- (p-) doping, which are much higher than the reported values for n-type Bi2Te2.79Se0.21polycrystalline alloy (ZT~1.2 at 357 K), and p-type nanocomposites Bi0.48Sb1.52Te3(ZT~1.4 at 475 K), thus the fluorinated Sn2Bi sheet can be a promising candidate for room-temperaturethermoelectric applications.

We demonstrate filled CoSb3skutterudite materials with excellent thermoelectric (TE) performance that results in one of the highest reported single stage module efficiency. The improvement in TE material performance was obtained by creating isotype n/n “bulk heterojunction” structure through assembly of novel skutterudite nanocrystals with different Yb-doping content. Combination of significant increase in carrier transport through heterojunction structure and reduction in long-range acoustic phonon transmission by two-phase mixture resulted in enhanced power factor and reduced lattice thermal conductivity. As a result, the figure-of-merit (zT) of heterojunction TE material is improved by more than 35% compared with pristine single homogeneous material. Using these improved TE materials, a high module conversion efficiency of ~9.15% was obtained when operating between 650 °C and 50 °C. This is one of the highest conversion efficiency among the practically measured single stage modules.