Shanghai University

About: Shanghai University is a education organization based out in Shanghai, Shanghai, China. It is known for research contribution in the topics: Microstructure & Catalysis. The organization has 59583 authors who have published 56840 publications receiving 753549 citations. The organization is also known as: Shànghǎi Dàxué.

Removal efficiency of arsenate and phosphate from aqueous solution using layered double hydroxide materials: intercalation vs. precipitation

Abstract: Adsorption behaviours of arsenate and phosphate over Mg-based and Ca-based layered double hydroxide (LDH) adsorbents have been examined in kinetics and thermodynamics. Removal of these anions from aqueous solution follows the Lagergren first-order and/or pseudo-second-order model, and the adsorption isotherm is well fitted with either the Langmuir or the Freundlich model. Structure analysis of used LDH adsorbents reveals that two processes, i.e. intercalation and precipitation, are responsible for the anion removal. Adsorption over the Mg-based LDH adsorbent occurs by way of intercalation into the interlayer spacing while that over the Ca-based adsorbent occurs by means of precipitation of dissolved Ca2+ with the anion. More particularly, we have found that As(V) at a concentration below 10 mg/L can be very efficiently removed through intercalation into the interlayer of reconstructed MgAl-LDHs, with less than 0.010 mg/L of As left in solution. We have also noted that phosphate at [P] up to 100 mg/L can be quickly and effectively removed through precipitation with CaAl-Cl-LDH, giving rise to ∼0.1 mg/L of P left in solution with the maximum adsorption amount up to 135 mg/g. Therefore, these two LDH materials (calcined Mg3Al-CO3-LDH and uncalcined Ca2Al-Cl-LDH) are potential cost-effective adsorbents for arsenate and phosphate, respectively.

Rumor spreading model considering forgetting and remembering mechanisms in inhomogeneous networks

Abstract: The SIHR rumor spreading model with consideration of the forgetting and remembering mechanisms was studied in homogeneous networks. We further investigate the properties of the SIHR model in inhomogeneous networks. The SIHR model is refined and mean-field equations are derived to describe the dynamics of the rumor spreading model in inhomogeneous networks. Steady-state analysis is carried out, which shows no spreading threshold existing. Numerical simulations are conducted in a BA scale-free network. The simulation results show that the network topology exerts significant influences on the rumor spreading: In comparison with the ER network, the rumor spreads faster and the final size of the rumor is smaller in BA scale-free network; the forgetting and remembering mechanisms greatly impact the final size of the rumor. Finally, through the numerical simulation, we examine the effects that the spreading rate and the stifling rate have on the the influence of the rumor. In addition, the no threshold result is verified.

Highly Sensitive Flexible Piezoresistive Pressure Sensor Developed Using Biomimetically Textured Porous Materials.

Abstract: In recent times, high-performance flexible pressure sensors that can be fabricated in an environmentally friendly and low-cost manner have received considerable attention owing to their potential applications in wearable health monitors and intelligent soft robotics. This paper proposes a highly sensitive flexible piezoresistive pressure sensor based on hybrid porous microstructures that can be designed and fabricated using a bio-inspired and low-cost approach employing the Epipremnum aureum leaf and sugar as the template. The sensitivity and detection limit of the obtained pressure sensor can be as high and low as 83.9 kPa-1 (<140 Pa) and 0.5 Pa, respectively. According to the mechanism and simulation analyses, the hybrid porous microstructures lower the effective elastic modulus of the sensor and introduce an additional pore resistance, which increases the contact area and conductive path with loads, thereby contributing to the high sensitivity that exceeds that of traditional microstructured pressure sensors. Real-time monitoring of human physiological signals such as finger pressing, voice vibration, swallowing activity, and wrist pulse is demonstrated for the proposed device. The high performance and easy fabrication of the hybrid porous microstructured sensor can encourage the development of a novel approach for the design and fabrication of future pressure sensors.

High thermoelectric performance in Te-free (Bi,Sb)2Se3via structural transition induced band convergence and chemical bond softening

Abstract: Semiconductors with converging multiple electronic valleys and soft chemical bonds are ideal for high-performance thermoelectrics. Narrow gap Bi2Se3 is a well-known three-dimensional topological insulator with non-trivial surface states, while possessing low thermoelectric properties due to its single-degenerate band conduction, despite being an important constituent of highly efficient n-type thermoelectric Bi2(Te,Se)3. Here we demonstrate that in Te-free Bi2−xSbxSe3 converging multiple electronic band valleys and strengthening phonon scattering can be realized simultaneously via a composition-induced (Sb-alloying) structural transition from a rhombohedral phase to an orthorhombic phase. The accompanying chemical bond softening and structural distortion cause significant modifications to the electronic band structure and phonon dispersion. The convergence of heavy bands realized in the orthorhombic phase (x ≥ 1.0) largely increases the electron density of states effective mass, and thus gives rise to a high Seebeck coefficient of ∼−280 μV K−1 at 800 K. Meanwhile, phonon softening and substantial lattice anharmonicity pertain to weak interchain interactions considerably block the heat-carrying acoustic phonons, resulting in ultralow lattice thermal conductivities of ∼0.6 W m−1 K−1 at 300 K and ∼0.3 W m−1 K−1 at 800 K. Consequently, a maximum thermoelectric figure of merit ZT of ∼1.0 can be achieved for n-type BiSbSe3, about three times higher than that of the optimized Bi2Se3. The moderately high ZT of Te-free BiSbSe3 makes it a promising candidate for low-mid temperature power generations. Furthermore, the concept of structural transition driven band convergence and chemical bond softening can be applied to improve the thermoelectric properties of other materials and may also shed light on identifying new materials.