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Trial‐to‐trial intraindividual reaction time variability (IIRTV) serves as an index of attentional control and related endogenous brain function. What determinants contribute to preschoolers' attentional control indexed by IIRTV remains unknown. The present study examined how catechol‐o‐methyltransferase (COMT) rs4680 polymorphism interacted with family functioning (cohesion and adaptability) to impact on preschoolers' attentional control indexed by IIRTV. One hundred forty‐four preschool children (Mage = 4.19, SD = 0.63) completed the flanker task to assess their IIRTV. Their parents were asked to fill out the Family Adaptability and Cohesion Evaluation Scale II to assess family functioning. After controlling for age, socioeconomic status (SES) and mean reaction time, results showed that the COMT rs4680 polymorphism was positively associated with preschoolers' IIRTV at the 5% significance level (p =.02) but not after multiple testing adjustment (p =.08). Moreover the COMT rs4680 polymorphism significantly interacted with family functioning to impact on preschoolers' IIRTV and the interaction effects remained significant after correction for multiple testing (p =.01, ΔR2 = 0.06 in congruent conditions; p =.04, ΔR2 = 0.04 in combined conditions). In addition, the significant interaction between SES and COMT rs4680 polymorphism was also found in the present study (p =.01, ΔR2 = 0.05 in congruent conditions; p =.05, ΔR2 = 0.03 in combined conditions). No sex differences were found in the present sample. The findings of the present study expand our knowledge about the gene × environment underpinnings of children's attentional control and endogenous brain function, and provide evidence for the Vantage Sensitivity model on children's development. [ABSTRACT FROM AUTHOR]

Studying the influence of oxygen on the growth and properties of diamond has research significance. In this paper, we created an oxygen-rich environment by adding Ni2O3 to the Fe–Ni–C system. Large single crystals of oxygen-containing diamond were successfully synthesized using the temperature gradient method (TGM) in a China-type large volume cubic high-pressure apparatus (CHPA) at 5.5–6.0 GPa and 1360–1600 °C. The results show that with the increase of the Ni2O3 content in the Fe–Ni–C system, the rate of diamond growth decreased while the conditions for diamond growth were enhanced. The morphology of the diamonds changed from {111}, {110} and {113} mixed faces to {111} dominant face. The IR results show that the presence of Ni2O3 increased the nitrogen content in diamonds from 237 ppm to 543 ppm. When 3.5 wt% Ni2O3 was added, A-centre nitrogen began to appear in the diamonds. The XPS results confirmed that oxygen successfully entered the diamond lattice in the form of C–O, C＝O, O–C＝O and N–O with a high concentration of Ni2O3 additives. Meanwhile, there were no obvious impurity inclusions and cracks in the diamond crystals. In addition, the Raman peak position of the diamond appeared to red shift, and the FWHM increased from 4.93 cm−1 to 5.52 cm−1. [ABSTRACT FROM AUTHOR]

By doping titanium hydride (TiH2) into boron carbide (B4C), a series of B4C + x wt% TiH2 (x = 0, 5, 10, 15, and 20) composite ceramics were obtained through spark plasma sintering (SPS). The effects of the sintering temperature and the amount of TiH2 additive on the microstructure, mechanical and electrical properties of the sintered B4C-TiB2 composite ceramics were investigated. Powder mixtures of B4C with 0–20 wt% TiH2 were heated from 1400 °C to 1800 °C for 20 min under 50 MPa. The results indicated that higher sintering temperatures contributed to greater ceramic density. With increasing TiH2 content, titanium diboride (TiB2) formed between the TiH2 and B4C matrix. This effectively improved Young's modulus and fracture toughness of the composite ceramics, significantly improving their electrical properties: the electrical conductivity reached 114.9 S⋅cm−1 at 1800 °C when x = 20. Optimum mechanical properties were obtained for the B4C ceramics sintered with 20 wt% TiH2, which had a relative density of 99.9 ± 0.1%, Vickers hardness of 31.8 GPa, and fracture toughness of 8.5 MPa⋅m1 / 2. The results indicated that the doping of fine Ti particles into the B4C matrix increased the conductivity and the fracture toughness of B4C. [ABSTRACT FROM AUTHOR]

The temperature in the high-pressure high-temperature (HPHT) synthesis is optimized to enhance the thermoelectric properties of high-density ZnO ceramic, Zn0.98Al0.02O. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy show that HPHT can be utilized to control the crystal structure and relative density of the material. High pressure can be utilized to change the energy band structure of the samples via changing the lattice constant of samples, which decreases the thermal conductivity due to the formation of a multi-scale hierarchical structure and defects. The electrical conductivity of the material reaches 6 × 104 S/m at 373 K, and all doped samples behave as n-type semiconductors. The highest power factor (6.42 μW ⋅ cm−1⋅K−2) and dimensionless figure of merit (zT = 0.09) are obtained when Zn0.98Al0.02O is produced at 973 K using HPHT, which is superior to previously reported power factors for similar materials at the same temperature. Hall measurements indicate a high carrier concentration, which is the reason for the enhanced electrical performance. [ABSTRACT FROM AUTHOR]

Diamond/aluminum composites with a high thermal conductivity of 529 W/(m•K) were prepared using pure aluminum as the matrix and 50 vol.% Ti-coated 200 µm diamond as the filling material within 10 min by high temperature (700 °C) and high pressure (3 GPa) powder metallurgy method. The morphology and properties of Ti-coated diamond were characterized by optical microscope and X-ray diffraction. The properties of the prepared diamond/aluminum composite were tested by laser thermal diffusion instrument, scanning electron microscope and thermal expansion instrument. It is found that the Ti-coating diamond prepared by spark plasma sintering is mainly composed of titanium and a small amount of titanium carbide. Compared with raw diamond under the same preparation conditions, the Ti-coated diamond could effectively improve the thermal conductivity of diamond/aluminum composites. Meanwhile, the high temperature and high pressure method can be used to prepare the full density of diamond/aluminum composites, which can effectively improve the interface bonding between aluminum matrix and diamond particles, reduce the interface spaces and effectively improve the thermal conductivity of composites. Compared with the conventional methods such as vacuum hot pressing, spark plasma sintering and gas pressure infiltration, the sample preparation period of high temperature and high pressure powder metallurgy is short (several minutes). This research is helpful to expand the preparation method of high thermal conductivity composites, expand the product types of domestic six-sided top press, and provide technical support for the preparation of other metal matrix thermal conductive composites. [ABSTRACT FROM AUTHOR]

The chemical composition can directly tune the transport properties of Cu2Se liquid-like materials, including the carrier concentration, carrier mobility and superionic feature. In this work, the off-stoichiometry effects of both the deficiency and excess of Cu on the phase transition and thermoelectric properties of Cu2+δSe (−0.1 ≤ δ ≤ 0.05) compounds are investigated. The Cu2+δSe samples were synthesized by a high-pressure and high-temperature (HPHT) technique in 30 minutes. Cu2+δSe (−0.1 ≤ δ < 0) existed as a mixture of the monoclinic α-Cu2Se phase and cubic β-Cu2Se phase at room temperature, while only the monoclinic α-Cu2Se phase was detected in the Cu2+δSe (0 ≤ δ ≤ 0.05) compounds. Increasing the Cu content can effectively regulate the carrier concentration and reduce the thermal conductivity from 1.45 W m−1 K−1 (δ = −0.1) to 0.47 W m−1 K−1 (δ = 0.05) at 843 K. The ultralow lattice thermal conductivity of 0.3 W m−1 K−1 was achieved for Cu1.97Se and Cu2.0Se by stoichiometry tuning. A maximum zT value of 1.46 at 843 K was obtained for Cu2.0Se, which is 100% higher than that of Cu1.9Se. This work demonstrates the potential of off-stoichiometry for tuning the TE properties of Ag+ and Cu+ based superionic materials. [ABSTRACT FROM AUTHOR]

High-pressure technique is an effective route to synthesize thermoelectric materials and tune transport properties simultaneously. In this work, S-doped copper–selenium compounds ( Cu 2 Se 1 − x S x , 0 ≤ x ≤ 0. 0 5) were successfully synthesized by high-pressure and high-temperature (HPHT) technology in just 30 min. Cu 2 Se 1 − x S x samples show layered morphology composed of abundant pores and lattice defects. The appropriate S introduction (x = 0. 0 1 and 0.03) can effectively enhance Seebeck coefficient and reduce the thermal conductivity of Cu 2 Se. Compared with the pure Cu 2 Se sample, Cu 2 Se 0. 9 7 S 0. 0 3 exhibits a 30% lower thermal conductivity, but the decline of power factor by the distinctly increased electrical resistivity at high temperature results in a smaller zT at temperature > 6 5 0  K. The variations of thermoelectric properties are resulted from the competitive effects between S-doping and actual composition change (Cu:S). It indicates that S-doping is not so effective in improving the zT value of Cu 2 Se materials by high-pressure synthesis. [ABSTRACT FROM AUTHOR]

This work is devoted to the nonlinear buckling of the hemispherical shells subjected to extremely high external pressure. The shells are made of maraging steel with yield strength of 2100 MPa. The experiment on a tentatively devised laboratory-scale hemispherical shell is conducted in high pressure chamber, after preciously fabricated, optically and ultrasonically measured. Numerical predictions are carried out and proved to have a good agreement with experimental results. The laboratory-scale hemispherical shell can borne the pressure as high as about 139 MPa and demonstrates an unstable post-buckling character and a local dimple post-buckling mode near the base. Based on the study, a segmented hemispherical configuration is conceived and evaluated numerically, which can provide a reference for the deep-sea pressure hull design made of maraging steel. • The collapse load and post-buckling character of the hemispherical hull made of high strength maraging steel are analyzed by experiment in high pressure chamber. • A promising design formula for full-ocean-depth manned cabin made of maraging steel is validated by the study. • A segmented hemispherical configuration is proposed which is benchmarked by the numerical buckling analysis of hemispherical pressure hull. [ABSTRACT FROM AUTHOR]

Cu2Se is a p-type semiconducting compound that possesses excellent thermoelectric properties which exhibit great potential for practical applications. In recent years, there have been many ways to improve thermoelectric properties. Reducing the thermal conductivity is a very effective way to obtain high performance thermoelectric materials. In this study, a series of Cu2−xLixSe (x = 0, 0.01, 0.02 and 0.03) polycrystalline bulk samples were successfully prepared by hot-pressing the nanopowders made by hydrothermal synthesis to investigate the doping effects of Li on the phase structure, microstructure and thermoelectric properties of Cu2Se. Compared with the Li-free Cu2Se, the introduction of Li element increases the Seebeck coefficient. Importantly, both nanopores and Li substitution were observed which can reduce κLvia increased scattering phonons. At 973 K, the Cu1.98Li0.02Se sample presented an excellent ZT of 2.14. [ABSTRACT FROM AUTHOR]