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Thermal interface materials (TIMs) are one of the important components of materials used in electronic packaging processes to reinforce the interface heat transfer between electronic components. High thermal conductive filler-reinforced polymer composites are receiving increasing attention in electronic packaging for their excellent thermal conductivity and low cost, but their applications are limited by complex preparation processes and difficult to produce on large scale. This paper presents an efficient blending method with dry ice airburst synergistic shear force field for large-scale preparation of natural rubber/expanded graphite (NR/EG) polymer composites. The thermal conductivity of the composite in presence of dry ice airburst is 2.317 W/(m·K) for EG content of 30 wt%, compared to 1.206 W/(m·K) for the control sample without dry ice airburst, an improvement of 92.1%, indicating a significant improvement in thermal conductivity. In addition, after introduction of dry ice, tensile strength and elongation at break of composites increased by 33.7% and 9.2%, respectively, showing promising mechanical properties. The calculations showed that the shear flow field strength was increased 68.2 times by heat absorption of dry ice, and the EG exfoliation mechanism was proposed. The strategy proposed in this work provide green, simple and efficient method to prepare high thermal conductive composites without the involvement of chemical solvents, which has enormous potential in large-scale preparation of high thermal conductivity filler reinforced polymer composites. This paper presents an efficient blending method with dry ice airburst synergistic shear force field for the large-scale preparation of natural rubber/expanded graphite (NR/EG) polymer composites, the thermal conductivity of the composite in the presence of dry ice airburst was 2.317 W/(m·K) for EG content of 30 wt%, compared to 1.206 W/(m·K) for the control sample without dry ice airburst, an improvement of 92.1%, indicating a significant improvement in thermal conductivity, owing to the enhanced exfoliation process of EG by dry ice airburst and sublimation heat absorption, the calculations showed that the shear flow field strength was increased 68.2 times by heat absorption of dry ice, and the EG exfoliation mechanism was proposed. Our proposed strategy allows the green and efficient preparation of highly thermally conductive composites without the involvement of chemical solvents and in an environmentally friendly and simple process, providing a solution for the large-scale practical preparation of high thermal conductivity filler reinforced polymer composites. [Display omitted] • Sublimation of dry ice promotes exfoliation and dispersion of EG. • With the introduction of dry ice, thermal conductivity is increased 92.1%. • The mechanism of introducing dry ice is proposed and the shear force is calculated to increase to 68.2 times. [ABSTRACT FROM AUTHOR]

The current study aims to illustrate male to female suicide rate ratios in the world and explore the correlations between female labour force participation rates (FLPR) and suicide rates of both genders. Further, whether the relationship of FLPR and suicide rates vary according to the human capabilities of a given country are examined. Using suicide data obtained from the World Health Organization Statistical Information System, suicide gender ratios of 70 countries are illustrated. Based on the level of Human Development Index (HDI) and FLPR, the Bayesian Information Criteria (BIC) was used to determine the optimal number of clusters of those countries. Graphic illustrations of FLPR and gender-specific suicide rates, stratified by each cluster were presented, and Pearson's correlation coefficients calculated. Three clusters are identified, there was no correlation between FLPR and suicide rates in the first cluster where both the HDI and FLPR were the highest (Male: r = 0.29, P = 0.45; Female: r = 0.01, P = 0.97); whereas in Cluster 2, higher level of FLPR corresponded to lower suicide rates in both genders, although the statistical significance was only found in females (Male: r = −0.32, P = 0.15; Female: r = −0.48, P = 0.03). In Cluster 3 countries where HDI/FLPR were relatively lower, increased FLPR was associated with higher suicide rates for both genders (Male: r = 0.32, P = 0.04; Female: r = 0.32, P = 0.05). The relationship between egalitarian gender norms and suicide rates varies according to national context. A greater egalitarian gender norms may benefit both genders, but more so for women in countries equipped with better human capabilities. Although the beneficial effect may reach a plateau in countries with the highest HDI/FLPR; whereas in countries with relatively lower HDI/FLPR, increased FLPR were associated with higher suicide rates. [ABSTRACT FROM AUTHOR]

ZnO nanofibers (ZnO NFs) were fabricated by electrospinning a dimethylformamide solution of zinc acetate containing polyvinylpyrrolidone and polymethylmethacrylate binary polymer matrix, followed by calcination. The obtained ZnO NFs are composed of close-packed ZnO nanoparticles of ca.20 nm in diameter. With Nafion acting as adhesive, the ZnO NF coated glassy carbon electrode (ZnO NF/GCE) has been prepared and applied as a new sensing platform for heavy metal determination with square wave stripping voltammetry. The high surface area and the strong affinity to cadmium (Cd) render the ZnO NF/GCE sensitive to Cd ion measurement. The experiment parameters were optimized by the design of orthogonal experiment. Under the optimal conditions, the current response exhibits a good linear relationship with the concentration of Cd(II) ranging from 4.8 × 10 −9 to 1.3 × 10 −6 mol L −1 ,with the detection limit of 1.8 × 10 −9 mol L −1 (S/N > 3). The developed sensor has been successfully applied for the determination of Cd(II) in water sample. The simultaneous analysis of Cd(II), Pb(II), Cu(II) and Hg(II) has been demonstrated to be feasible. [ABSTRACT FROM AUTHOR]

Commercial purposes of two-dimensional silicene are usually suppressed in nanoelectronic and optoelectronic devices by its zero-band gap. Here, the halogen atoms are detected to open the bandgap of silicene monolayer by the chemical functionalization, and comprehensive analysis of the effects of halogenation on the structural, electronic, mechanical and optical properties are conducted via first-principles calculations within the framework of density functional theory. Our simulation results prove that the halogenation makes silicene structure more distorted but maintains good stability. Specifically, Full- and Janus-functionalization endow silicene with direct bandgap ranging from 1.536 to 2.123 eV by the HSE06 functional, while half-functionalization renders silicene metallic and retains semiconducting characteristics. In the above three configurations, the bond between the halogen atom and the host Si atom is predominantly ionic and the ionicity of the former two configurations decreases as the period number of the halogen atom increases. Furthermore, the halogenated silicene monolayers exhibit a hard mechanical property and relatively strong ability to resist deformation based on calculated Young's modulus Y and Shear modulus G except for the F–Si monolayer. And the light absorption of pristine silicene monolayer is increased by halogenation in the UV–Vis light spectrum. • Two-dimensional silicene monolayer is semi-metallic due to its Dirac cone at K point. • Incorporating halogen atoms induces intrinsic structural distortion of silicene monolayer. • The full- and Janus-functionalization successfully opens its energy gap ranging from 1.536 to 2.123 eV. • The bond between the halogen atom and the host silicon atom is mainly ionic. • The absorption of silicene monolayer is increased by halogenation in the UV-Vis region and reaches 84400 cm−1 at 4.04 eV. [ABSTRACT FROM AUTHOR]

In this paper, a new type of low molecular weight gelators (LMWGs), C2-symmetric benzene-based hydrogel (C2-BHG) with a 1,4-dimine benzene was self-assembled on glassy carbon electrode (GCE) and mica surface based on the hydrogen bond or hydrophobic interaction. Atomic force microscopy (AFM) characterization demonstrated the formation process of the C2-BHG hydrogel layer from particles to clusters, and finally to interconnected fiber network gel. The C2-BHG hydrogel layer resulted in the increase of the hydrophilicity of GCE surface. The C2-BHG modified GCEs (C2-BHG/GCE) with different assembly time were studied by cyclic voltammetry and electrochemical impedance spectroscopy in the presence of Fe(CN) 6 4−/3− redox probe. The rich amide and hydroxyl groups in the gel film make the C2-BHG/GCE suitable as ultrasensitive sensor for the detection of Cu(II) ions by stripping voltammetry with the limit of detection of 5×10 −10 g/L (S/N>3). Under the optimal conditions, the two linear ranges of Cu(II) ions were found to be 1×10 −9 ∼1×10 −7 g/L and 1×10 −7 ∼1×10 −4 g/L. The strong coordination interaction of C2-BHG with Cu(II) ions was confirmed by UV-Visible characterization. This new type of C2-BHG modified electrode was promising for highly sensitive Cu(II) ions sensor application due to high stability and excellent selectivity of the analytical signal. [ABSTRACT FROM AUTHOR]