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 & Laser. 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.

3D viscous-spring artificial boundary in time domain

Abstract: After a brief review of studies on artificial boundaries in dynamic soil-structure interaction, a three-dimensional viscous-spring artificial boundary (VSAB) in the time domain is developed in this paper. First, the 3D VSAB equations in the normal and tangential directions are derived based on the elastic wave motion theory. Secondly, a numerical simulation technique of wave motion equations along with the VSAB condition in the time domain is studied. Finally, numerical examples of some classical elastic wave motion problems are presented and the results are compared with the associated theoretical solutions, demonstrating that high precision and adequate stability can be achieved by using the proposed 3D VSAB. The proposed 3D VSAB can be conveniently incorporated in the general finite element program, which is commonly used to study dynamic soil-structure interaction problems.

Highly efficient p-type Cu3P/n-type g-C3N4 photocatalyst through Z-scheme charge transfer route

Abstract: Phosphides exhibit relatively low overpotential for electrical hydrogen evolution reaction (HER), thus they have great potential to be used for cocatalyst for photocatalyst. Cu3P, as a p-type semiconductor, tends to form a p-n junction with an n-type photocatalyst. Typically, it is treated as a sensitizer to extend the light absorption. However, its function and work mechanism are not fully understood in the catalyst system. In this report, we synthesized g-C3N4 and loaded Cu3P nanoparticle on its surface. The photoluminescence (PL) spectra, photocurrent and electrochemical impedance spectra confirm the Cu3P greatly enhance the charge separation process. Electrochemical HER results indicate that the composites have lower over-potential for HER. These results confirm the Cu3P works as a cocatalyst in the system, not a sensitizer. Further, we tracked the photogenerated electron transfer direction via photodeposition of Pt nanoparticles. The Pt nanoparticles tend to deposit near the Cu3P nanoparticles. That illustrates the photogenerated electron will be left on Cu3P nanoparticles. On the other hand, the photocatalytic decomposition of Rhodamine B (RhB) illustrates that the holes are left on the g-C3N4 due to both g-C3N4 and Cu3P/g-C3N4 have similar decomposition rate, but the Cu3P cannot decompose RhB. Based on these, we proposed the photogenerated electron of g-C3N4 recombine with the hole of Cu3P, the photogenerated electron of Cu3P will be left for HER. That reasonably explain the cocatalyst function of Cu3P in the composite catalyst system.

Microporous metal–organic frameworks with open metal sites as sorbents for selective gas adsorption and fluorescence sensors for metal ions

Abstract: Two cluster-based microporous MOFs containing coordination unsaturated metal(II) sites (or open metal(II) sites) have been constructed from boxlike or cagelike {M3}x SBUs. They both exhibit highly selective uptake for CO2 over CH4 and N2 under ambient conditions. More importantly, MOF-1 also provides an ideal luminescence sensor for selective probing Ba2+ and Cu2+ ions based on significant luminescence enhancement or quenching.

Visible light photocatalytic reduction of Cr(VI) on TiO2 in situ modified with small molecular weight organic acids

Abstract: Visible light photoreduction of toxic Cr(VI) over TiO 2 was achieved through surface modification with small molecular weight organic acids (SOAs) as sacrificial organics. Because neat anatase TiO 2 is active only under UV light irradiation ( λ 2 dispersions being irradiated with visible light ( λ > 420 nm). However, when a small amount of colorless SOAs was added into the TiO 2 dispersion, a charge-transfer-complex (CTC) was formed between TiO 2 and SOA, which was sensitive to visible light irradiation and induced the photo-oxidation of SOA and photoreduction of Cr(VI). It was observed that about 95% of added Cr(VI) (0.2 mmol L −1 ) was removed in the visible light-illuminated TiO 2 (1.0 g L −1 ) dispersions at pH 3.0 within 2 h by adding 0.2 mmol L −1 tartaric acid as a SOA. The SOA-induced photoreduction of Cr(VI) proceeded via a CTC-mediated path, being governed by chemical structures of sacrificial SOAs. A higher energy of the highest occupied molecular orbital or lower ionization potential of SOAs is favorable to electron transfer within TiO 2 -SOA complex, thereby accelerating the photoreduction of Cr(VI). The Cr(VI) removal was further enhanced by increasing SOA concentration and/or decreasing solution pH.