Harbin Institute of Technology

About: Harbin Institute of Technology is a education organization based out in Harbin, China. It is known for research contribution in the topics: Microstructure & Control theory. The organization has 88259 authors who have published 109297 publications receiving 1603393 citations. The organization is also known as: HIT.

Facile synthesis of electrospun MFe2O4 (M = Co, Ni, Cu, Mn) spinel nanofibers with excellent electrocatalytic properties for oxygen evolution and hydrogen peroxide reduction

Abstract: Designing and preparing porous transition metal ferrites without using any template, shape-directing agent, and surfactant is a challenge. Herein, heterojunction MFe2O4 (M = Co, Ni, Cu, Mn) nanofiber (NF) based films with three-dimensional configurations were synthesized by electrospinning and the subsequent thermal treatment processes. Characterization results indeed show the 3D net-like textural structures of the electrospun spinel-type MFe2O4 NFs. In particular, the resulting MFe2O4 NFs have lengths up to several dozens of micrometers with an average diameter size of about 150 nm and possess abundant micro/meso/macropores on both the surface and within the films. The hierarchically porous structures and high surface areas of these MFe2O4 NFs (for example, the CoFe2O4 NFs possess a larger BET specific surface area (61.48 m2 g−1) than those of the CoFe2O4 NPs (5.93 m2 g−1)) can afford accessible transport channels for effectively decreasing the mass transport resistances, enhancing the electrical conductivity, and increasing the density and reactivity of the exposed catalytic active sites. All these advantages will be responsible for the better electrocatalytic performances of these MFe2O4 NFs compared with their structural isomers (i.e. the MFe2O4 NPs) for the oxygen evolution reaction (OER) and H2O2 reduction in alkaline solution. Meanwhile, both the OER and H2O2 reduction catalytic activities for these MFe2O4 NFs obey the order of CoFe2O4 NFs > CuFe2O4 NFs > NiFe2O4 NFs > MnFe2O4 NFs > Fe2O3 NFs. The CoFe2O4 NFs represent a new class of highly efficient non-noble-metal catalysts for both OER and H2O2 reduction/detection in alkaline media.

3D Printing of Graphene Aerogels.

Abstract: 3D printing of a graphene aerogel with true 3D overhang structures is highlighted. The aerogel is fabricated by combining drop-on-demand 3D printing and freeze casting. The water-based GO ink is ejected and freeze-cast into designed 3D structures. The lightweight (<10 mg cm(-3) ) 3D printed graphene aerogel presents superelastic and high electrical conduction.

Back gated multilayer InSe transistors with enhanced carrier mobilities via the suppression of carrier scattering from a dielectric interface.

Abstract: The back gate multilayer InSe FETs exhibit ultrahigh carrier mobilities, surpassing all the reported layer semiconductor based electronics with the same device configuration, which is achieved by the suppression of the carrier scattering from interfacial coulomb impurities or surface polar phonons at the interface of an oxidized dielectric substrate. The room-temperature mobilities of multilayer InSe transistors increase from 64 cm(2)V(-1)s(-1) to 1055 cm(2)V(-1)s(-1) using a bilayer dielectric of poly-(methyl methacrylate) (PMMA)/Al2O3. The transistors also have high current on/off ratios of 1 × 10(8), low standby power dissipation, and robust current saturation in a broad voltage range.

Microstructure and compressive properties of AlCrFeCoNi high entropy alloy

Abstract: An AlCrFeCoNi high entropy alloy was prepared by vacuum arc melting. Only diffraction peak corresponding to a BCC crystal structure is observed for this AlCrFeCoNi high entropy alloy. The microstructure of this AlCrFeCoNi alloy is polygonal grains with intragranular dendritic segregation. Dendritic segregation area is found to be Al, Ni rich and Cr, Fe deplete, while interdendritic segregation area is Cr, Fe rich and Al, Ni deplete. The distribution of Co is essentially identical. The fine microstructure of dendritic segregation area and of interdendritic segregation area is found to be nanoscale spherical precipitates morphology and basket-weave morphology, respectively. Results of EDS attached on high resolution scanning electron microscope (SEM) revealed that these morphological characteristics are also resulted from elements segregation. This AlCrFeCoNi high entropy alloy exhibits excellent compressive properties. The yield stress, compressive strength and plastic strain of the alloy reaches 1250.96, 2004.23 MPa, and 32.7%, respectively. The fracture mechanism of this AlCrFeCoNi high entropy alloy is observed as cleavage fracture and slip separation.