Interfacial liquid–vapor phase change and entropy generation in pool boiling experiment for titanium tetrachloride

Journal of Thermal Analysis and Calorimetry - Interfacial temperatures and pressures in liquid and vapor phases near liquid–vapor interfaces in pool boiling experiment for titanium...     

SF-SIMM high-dimensional hyperchaotic map and its performance analysis

Derived from Sine map and an iterative chaotic map with infinite collapse (ICMIC), a new high-dimensional hyperchaotic map, sinusoidal feedback Sine ICMIC modulation map (SF-SIMM), is proposed. Two-dimensional (2D) model of SF-SIMM is investigated as an example, and its chaotic performances are evaluated. Results show that it has complicated phase space trajectory, infinite equilibrium points, hyperchaotic behaviors, rather large maximum Lyapunov exponent, three typical bifurcations and multiple coexisting attractors with odd symmetry. Furthermore, it has advantages in complexity, distribution characteristics and zero correlation and can generate two independent pseudo-random sequences simultaneously. Therefore, it has good application prospects in secure communication.     

Photocatalytic properties of Zinc selenide doped with cobalt oxide nanocomposite

In this work, ZnSe/Co₃O₄ was synthesized by hydrothermal method. The samples were characterized by XRD, SEM, TEM, EDS, XPS, BET, UV–vis techniques. The activity of the composite photocatalytic materials was detected by visible light catalytic degradation of methylene blue (MB). The catalytic effect was the most obvious when the composite ratio was 1:10, with the removal rate reaching to 93.6% of 10 ?mg/L MB within 120 ?min of visible light irradiation. After further analysis of the catalyst, ZnSe/Co₃O₄ has a broader application prospect due to its high efficiency and low price.     

Synthesis of micro-FeTi powders by direct electrochemical reduction of ilmenite in CaCl2-NaCl molten salt

Micro-ferrotitanium powders have been prepared by molten salt electrolysis via directly electrochemical reduction of solid ilmenite in eutectic CaCl₂-NaCl melt at 973 K. In the direct electrochemical reduction process, the reduction of FeTiO₃ first gives rise to the formation of Fe and CaTiO₃, which as intermediates will be further deoxidized at the interface of iron metals, solid CaTiO₃ matrix, and electrolyte to directly form ferrotitanium alloy powders in porous structure. Furthering the electrolytic time can promote the dense structure of ilmenite pellet turn to be more porous, indicating pores inside the pellet are sufficient for the diffusion of oxygen ions. Based on the reduction behavior of partially reduced powders in metallic cavity electrode during the cathodic potentiostatic electrolysis, it shows that the slow deoxidization rate is mainly caused by the more and more difficult reduction of CaTiO₃ than that of FeTiO₃.

     

Hard-Sphere Random Close-Packed Au47Cd2(TBBT)31 Nanoclusters with a Faradaic Efficiency of Up to 96 % for Electrocatalytic CO2 Reduction to CO

Metal nanoclusters have recently attracted considerable attention, not only because of their special size range but also because of their well-defined compositions and structures. However, subtly tailoring the compositions and structures of metal nanoclusters for potential applications remains challenging. Now, a two-phase anti-galvanic reduction (AGR) method is presented for precisely tailoring Au₄₄(TBBT)₂₈ to produce Au₄₇Cd₂(TBBT)₃₁ nanoclusters with a hard-sphere random close-packed structure, exhibiting Faradaic efficiencies of up to 96 % at −0.57 V for the electrocatalytic reduction of CO₂ to CO.     

Unraveling chemical structure of laminar premixed tetralin flames at low pressure with photoionization mass spectrometry and kinetic modeling

This work reports an investigation on laminar premixed flames of tetralin at 30 Torr and equivalence ratios of 0.7 and 1.7. Measurements of the chemical structure including identification and mole fraction measurements of free radicals, isomers, and polycyclic aromatic hydrocarbons (PAHs) were performed using synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV‐PIMS). A kinetic model with 296 species and 1 577 reactions was developed and validated against the flame chemical structure data measured in this work. Modeling analysis reveals the key reaction pathways in tetralin decomposition and PAHs formation. The H‐atom abstraction reactions by H, O, and OH are found to control the consumption of tetralin in the lean flame, while those by H play the dominant role in the rich flame. Indene and naphthalene have very high concentration levels in the rich tetralin flame due to the existence of direct formation pathways from the decomposition of tetralin. The two bicyclic PAHs and their radicals play significant roles in the PAHs growth process of tetralin combustion, which results in the high sooting tendency of tetralin compared to those of alkylbenzenes with smaller or same carbon atom numbers.     

Synthesis and properties of hyperbranched polyimides derived from novel triamine with prolonged chain segments

Novel pyridine‐containing hyperbranched polyimides (HBPIs) were synthesized by using a new triamine 2,4,6‐tris[3‐(4‐aminophenoxy)phenyl]pyridine with prolonged chain segments, ether linkage and meta‐linked units as a BB′₂‐like monomer, various commercial aromatic dianhydrides as A₂ monomers. Most of the obtained HBPIs were readily soluble in common organic solvents such as N,N‐dimethylformamide, N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidone, m‐Cresol, and so forth. Meanwhile, they also had good thermal stability with the glass transition temperatures (T_gs) all above 210 °C, the temperature at 10% weight loss of 537.1–574.4 °C in nitrogen atmosphere. Strong and flexible HBPI films were obtained, which had good mechanical properties with tensile strengths of 83.3–95.8 MPa, tensile modulus of 1.82–2.43 GPa and elongations at break of 4.84–6.98%. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2425–2437