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.

Facile Synthesis of Au-Coated Magnetic Nanoparticles and Their Application in Bacteria Detection via a SERS Method

Abstract: This study proposes a facile method for synthesis of Au-coated magnetic nanoparticles (AuMNPs) core/shell nanocomposites with nanoscale rough surfaces. MnFe2O4 nanoparticles (NPs) were first modified with a uniform polyethylenimine layer (2 nm) through self-assembly under sonication. The negatively charged Au seeds were then adsorbed on the surface of the MnFe2O4 NPs through electrostatic interaction for Au shell formation. Our newly developed sonochemically assisted hydroxylamine seeding growth method was used to grow the adsorbed gold seeds into large Au nanoparticles (AuNPs) to form a nanoscale rough Au shell. Au-coated magnetic nanoparticles (AuMNPs) were obtained from the intermediate product (Au seeds decorated magnetic core) under sonication within 5 min. The AuMNPs were highly uniform in size and shape and exhibited satisfactory surface-enhanced Raman scattering (SERS) activity and strong magnetic responsivity. PATP was used as a probe molecule to evaluate the SERS performance of the synthesized A...

Hydrothermal preparation of BiVO4 powders

Abstract: Monoclinic bismuth vanadate (BiVO 4 ) powders were prepared by a mild hydrothermal method, using an aqueous solution of bismuth nitrate and two different vanadium sources (V 2 O 5 and NaVO 3 ) The characterization of as-prepared BiVO 4 was carried out by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) The results revealed that in the present work the temperature of 200 and 140 °C are sufficient to prepare phase pure BiVO 4 powders from V 2 O 5 and NaVO 3 , respectively The BiVO 4 sample prepared from V 2 O 5 consists of an agglomeration of small rod-like particles When BiVO 4 was prepared from NaVO 3 , monoclinic BiVO 4 powder with a plate form is obtained

Coupling of electrochemically triggered thermal and mechanical effects to aggravate failure in a layered cathode.

Abstract: Electrochemically driven functioning of a battery inevitably induces thermal and mechanical effects, which in turn couple with the electrochemical effect and collectively govern the performance of the battery. However, such a coupling effect, whether favorable or detrimental, has never been explicitly elucidated. Here we use in situ transmission electron microscopy to demonstrate such a coupling effect. We discover that thermally perturbating delithiated LiNi0.6Mn0.2Co0.2O2 will trigger explosive nucleation and propagation of intragranular cracks in the lattice, providing us a unique opportunity to directly visualize the cracking mechanism and dynamics. We reveal that thermal stress associated with electrochemically induced phase inhomogeneity and internal pressure resulting from oxygen release are the primary driving forces for intragranular cracking that resembles a “popcorn” fracture mechanism. The present work reveals that, for battery performance, the intricate coupling of electrochemical, thermal, and mechanical effects will surpass the superposition of individual effects. Electrochemical processes induce thermo-mechanical effects that mediate battery performance. Here the authors directly visualize cracking dynamics in a thermally perturbed, delithiated LiNi0.6Mn0.2Co0.2O2 cathode to demonstrate coupling between thermal, mechanical and electrochemical factors.

Microsphere-coupled scanning laser confocal nanoscope for sub-diffraction-limited imaging at 25 nm lateral resolution in the visible spectrum.

Abstract: We report a direct optical super-resolution imaging approach with 25 nm (∼λ/17) lateral resolution under 408 nm wavelength illumination by combining fused silica and polystyrene microspheres with a conventional scanning laser confocal microscope (SLCM). The microsphere deposited on the target surface generates a nanoscale central lobe illuminating a sub-diffraction-limited cross-section located on the target surface. The SLCM confocal pinhole isolates the reflected light from the near-field subdiffractive cross-section and suppresses the noises from the side lobe and the far-field paraxial focal point. The structural detail of the subdiffractive cross-section is therefore captured, and the 2D target surface near the bottom of microspheres can be imaged by intensity-based point scanning.