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.

Embedded piezoresistive cement-based stress/strain sensor

Abstract: In order to develop one type of embedded piezoresistive cement-based stress/strain sensor (PCSS) to monitor the local compressive stress/strain of concrete structures, we explore the piezoresistivity of cement-based material with carbon fiber and carbon black under single compressive loading and repeated compressive loads at different loading amplitudes, and find it is reversible and stable within the elastic regime. This justifies the use of cement-based material with carbon fiber and carbon black in the manufacture of embedded PCSS. PCSS based on the piezoresistivity of cement-based material with carbon fiber and carbon black is tested with compressive stress/strain in the range 0 MPa (0 μɛ) to 8 MPa (476 μɛ) for performance evaluation. Results indicate that PCSS can be used to achieve a sensitivity of 1.35% MPa−1 (0.0227% μɛ−1, gage factor of 227), linearity of 4.17% (4.16%), repeatability of 4.05% (4.06%) and hysteresis of 3.61% (3.62%), and the relationship between its input (compressive stress/strain) and output (fractional change in electrical resistivity) is Δρ = −1.35σ (Δρ = −0.0227ɛ). These findings suggest that this newly developed sensor can be used as one of the alternatives to monitor the compressive stress/strain of concrete structures.

Facile approach to synthesize g-PAN/g-C3N4 composites with enhanced photocatalytic H2 evolution activity.

Abstract: Novel composites consisting of graphitized polyacrylonitrile (g-PAN) nanosheets grown on layered g-C3N4 sheets were synthesized through a facile one-step thermal condensation of PAN and melamine for the first time. Photoluminescence spectroscopy and the photoelectrochemical measurements reveal that g-PAN nanosheets act as effective electron transfer channels to facilitate charge carrier separation in g-PAN/g-C3N4 composites. The g-PAN/g-C3N4 composites exhibit significantly enhanced visible-light photocatalytic performance for H2 evolution over pristine g-C3N4. The 5.0 wt % g-PAN/g-C3N4 composite has optimal H2 evolution rate of 37 μmol h–1, exceeding 3.8 times over pristine g-C3N4. We have proposed a possible mechanism for charge separation and transfer in the g-PAN/g-C3N4 composites to explain the enhanced photocatalytic performance.

Guided Locality Preserving Feature Matching for Remote Sensing Image Registration

Abstract: Feature matching, which refers to establishing reliable correspondences between two sets of feature points, is a critical prerequisite in feature-based image registration. This paper proposes a simple yet surprisingly effective approach, termed as guided locality preserving matching, for robust feature matching of remote sensing images. The key idea of our approach is merely to preserve the neighborhood structures of potential true matches between two images. We formulate it into a mathematical model, and derive a simple closed-form solution with linearithmic time and linear space complexities. This enables our method to accomplish the mismatch removal from thousands of putative correspondences in only a few milliseconds. To handle extremely large proportions of outliers, we further design a guided matching strategy based on the proposed method, using the matching result on a small putative set with a high inlier ratio to guide the matching on a large putative set. This strategy can also significantly boost the true matches without sacrifice in accuracy. Experiments on various real remote sensing image pairs demonstrate the generality of our method for handling both rigid and nonrigid image deformations, and it is more than two orders of magnitude faster than the state-of-the-art methods with better accuracy, making it practical for real-time applications.

Trace Cupric Species Triggered Decomposition of Peroxymonosulfate and Degradation of Organic Pollutants: Cu(III) Being the Primary and Selective Intermediate Oxidant

Abstract: Activation of persulfates to degrade refractory organic pollutants is currently a hot topic of advanced oxidation. Developing simple and effective activation approaches is crucial for the practical application of persulfates. We report in this research that trace cupric species (Cu(II) in several μM) can efficiently trigger peroxymonosulfate (PMS) oxidation of various organic pollutants under slightly alkaline conditions. The intermediate oxidant dominating this process was investigated with electron paramagnetic resonance (EPR), chemical probing, and in situ Raman spectroscopy. Unlike conventional PMS activation, which generates sulfate radical, hydroxyl radical, or singlet oxygen as major oxidants, Cu(III) was confirmed to be the primary and selective intermediate oxidant during the Cu(II)/PMS oxidation. Hydroxyl radical is the secondary intermediate oxidant formed from the reaction of Cu(III) with OH-. Hybrid oxidation by the two oxidants imparts Cu(II)/PMS with high efficiency in the degradation of a series of pollutants. The results of this work suggest that, with no need of introducing complex catalysts, trace Cu(II) inherent in or artificially introduced to some water or wastewater can effectively trigger PMS oxidation of organic pollutants.