Beijing University of Technology

About: Beijing University of Technology is a education organization based out in Beijing, Beijing, China. It is known for research contribution in the topics: Microstructure & Computer science. The organization has 31929 authors who have published 31987 publications receiving 352112 citations. The organization is also known as: Běijīng Gōngyè Dàxué & Beijing Polytechnic University.

Hydrothermal Synthesis and Photocatalytic Properties of Pyrochlore La2Sn2O7 Nanocubes

Abstract: Nanocubic La2Sn2O7 photocatalysts with pyrochlore structure have been successfully synthesized by a one-pot hydrothermal method. The effects of alkaline concentration, reaction time, and hydrothermal temperature on the structures and morphologies of the resultant products were investigated. On the basis of characterization results from X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED), a possible growth mechanism of the nanocubes under the hydrothermal conditions was proposed. The absorption spectra of as-prepared cubic La2Sn2O7 photocatalyst were determined by UV−vis spectrometer. Photocatalytic experiments showed that the La2Sn2O7 samples not only had a high activity for degradation of methyl orange, but also had the activity for generating H2 with a rate of 39 μmol/h under ultraviolet light irradiation.

Review and perspective on ultrafast wavelength-size electro-optic modulators

Abstract: As electronic device feature sizes scale-down, the power consumed due to onchip communications as compared to computations will increase dramatically; likewise, the available bandwidth per computational operation will continue to decrease. Integrated photonics can offer savings in power and potential increase in bandwidth for onchip networks. Classical diffraction-limited photonics currently utilized in photonic integrated circuits (PIC) is characterized by bulky and inefficient devices compared to their electronic counterparts due to weak light–matter interactions (LMI). Performance critical for the PIC is electro-optic modulators (EOM), whose performances depend inherently on enhancing LMIs. Current EOMs based on diffraction-limited optical modes often deploy ring resonators and are consequently bulky, photon-lifetime modulation limited, and power inefficient due to large electrical capacitances and thermal tuning requirements. In contrast, wavelength-scale EOMs are potentially able to surpass fundamental restrictions set by classical (i.e. diffraction-limited) devices via (a) high-index modulating materials, (b) nonresonant field and density-of-states enhancements such as found in metal optics, and (c) synergistic onchip integration schemes. This manuscript discusses challenges, opportunities, and early demonstrations of nanophotonic EOMs attempting to address this LMI challenge, and early benchmarks suggest that nanophotonic building blocks allow for densely integrated high-performance photonic integrated circuits.

Vibration and bending behavior of functionally graded nanocomposite doubly-curved shallow shells reinforced by graphene nanoplatelets

Abstract: Free vibration and static bending of functionally graded (FG) graphene nanoplatelet (GPL) reinforced composite doubly-curved shallow shells with three distinguished distributions are analyzed. Material properties with gradient variation in the thickness aspect are evaluated by the modified Halpin-Tsai model. Mathematical model of the simply supported doubly-curved shallow shells rests upon Hamilton Principle and a higher order shear deformation theory (HSDT). The free vibration frequencies and bending deflections are gained by taking into account Navier technique. The agreement between the obtained results and ANSYS as well as the prior results in the open literature verifies the accuracy of the theory in this article. Further, parametric studies are accomplished to highlight the significant influence of GPL distribution patterns and weight fraction, stratification number, dimensions of GPLs and shells on the mechanical behavior of the system.