Hong Liu

Bio: Hong Liu is an academic researcher from Shandong University. The author has contributed to research in topics: Medicine & Materials science. The author has an hindex of 100, co-authored 1905 publications receiving 57561 citations. Previous affiliations of Hong Liu include Shanghai University & Guangzhou University.

Optical waveguide in stoichiometric lithium niobate formed by 500 keV proton implantation

Abstract: We report on the fabrication of planar waveguide in stoichiometric lithium niobate by 500 keV proton implantation with a dose of 1x10(17) ions/cm(2). The formation of n(e) enhancement planar waveguide in the crystal was disclosed by the dark mode spectra and the subsequent endface coupling measurement. The absorption spectra show that the postannealing treatments above 400 masculineC temperature can remove the color centers induced by implantation efficiently. The propagation loss and near-field profiles of the planar waveguide were obtained with an end-face coupling system.

Cytocompatible 3D chitosan/hydroxyapatite composites endowed with antibacterial properties: toward a self-sterilized bone tissue engineering scaffold

Abstract: Bone tissue scaffolds based on bioactive polymer–hydroxyapatite composites have caused infections that seriously limit their extended application. In this study, we proposed a practical ion substitution method to synthesize in situ silver phosphate on the surface of a two-level, three-dimensional chitosan/nano-hydroxyapatite scaffold. A release test of silver ions in a phosphate buffered saline (PBS) solution was performed to demonstrate that silver ions were released continuously from the silver phosphate during the initial 6 days of the study. The antibacterial property and cytocompatibility of the scaffolds treated with different concentrations of silver nitrate solution were assessed by in vitro assays with Escherichia coli and MC3T3-E1, respectively. The ability of the silver-containing scaffolds to induce bacteriostasis was confirmed by the inhibition zone (15 mm) and high bactericidal rate (>99 %). Cell proliferation, morphology and the alkaline phosphatase activity of MC3T3-E1 cultured on the scaffold with low silver phosphate contents were comparable with those cultured on control samples.

Yb sensitized near-stoichiometric Er:LiNbO3 single crystal: a matrix for optical communication and upconversion emission

Abstract: Ytterbium and erbium codoped crystals have attracted considerable interest in the application of eye-safe laser, upconversion laser, and low-loss optical communication. Despite the lithium niobate (LiNbO3, LN) single crystal has been accepted as an ideal crystal matrix for Yb3+ and Er3+ ions possessing significant application potential in self-upconversion laser, the Yb and Er codoped near-stoichiometric LN (NSLN) crystal has rarely been studied. This is due to the difficulty of the NSLN crystal growth compared with that of the congruent LN (CLN). In this paper, an Yb, Er codoped near-stoichiometric LN (Yb, Er:NSLN) crystal was grown by the Czochrolski method for the first time. Spectra studies showed the constrained peak splitting at 378, 526, and 650 nm of the Yb, Er:NSLN crystal compared with Yb, Er:CLN crystal. It was attributed to the low concentration of intrinsic defects which constrained the Stark-split of the three energy levels of 4G11/2, 2H11/2, and 4F9/2 energy states. Some spectral changes ar...

Rethinking Spatial Invariance of Convolutional Networks for Object Counting

Abstract: Previous work generally believes that improving the spatial invariance of convolutional networks is the key to object counting. However, after verifying several mainstream counting networks, we surprisingly found too strict pixel-level spatial invariance would cause overfit noise in the density map generation. In this paper, we try to use locally connected Gaussian kernels to replace the original convolution filter to estimate the spatial position in the density map. The purpose of this is to allow the feature extraction process to potentially stimulate the density map generation process to overcome the annotation noise. Inspired by previous work, we propose a low-rank approximation accompanied with translation invariance to favorably implement the approximation of massive Gaussian convolution. Our work points a new direction for follow-up research, which should investigate how to properly relax the overly strict pixel-level spatial invariance for object counting. We evaluate our methods on 4 mainstream object counting networks (i.e., MCNN, CSRNet, SANet, and ResNet-50). Extensive experiments were conducted on 7 popular benchmarks for 3 applications (i.e., crowd, vehicle, and plant counting). Experimental results show that our methods significantly outperform other state-of-the-art methods and achieve promising learning of the spatial position of objects11Code is at https://github.com/zhiqic/Rethinking-Counting.

Thermally-assisted photodegradation of lignin by TiO 2 /H 2 O 2 under visible/near-infrared light irradiation

Abstract: As a bio-recalcitrant organic pollutant in paper mill effluent, lignin is generally removed by an advanced oxidation process, such as a TiO2/H2O2 photocatalytic technique under irradiation with ultraviolet light, which only accounts for less than 5% of sunlight. Herein, we reported a TiO2/H2O2-based thermally-assisted photocatalytic process that allows lignin to be efficiently degraded under visible/near-infrared light at an elevated temperature. Adsorption of H2O2 on TiO2 nanoparticles and an increase of temperature facilitate the production and separation of charge carriers under near-infrared and visible light irradiation, accelerate carrier transfer at the TiO2-electrolyte interface and promote the production of hydroxyl radicals. A higher level of H2O2 addition results in an increased degradation rate of lignin, while the optimal temperature for the thermally-assisted photodegradation of lignin is 70°C. A charge carrier excitation and transfer process was proposed for the TiO2/H2O2 thermally-assisted photocatalytic process. This work describes a new method for the photodegradation of organic pollutants, such as residual lignin in paper mill effluent, using wide band gap semiconductors under visible and near-infrared light irradiation.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

The chemistry of two-dimensional layered transition metal dichalcogenide nanosheets

Abstract: Ultrathin two-dimensional nanosheets of layered transition metal dichalcogenides (TMDs) are fundamentally and technologically intriguing. In contrast to the graphene sheet, they are chemically versatile. Mono- or few-layered TMDs - obtained either through exfoliation of bulk materials or bottom-up syntheses - are direct-gap semiconductors whose bandgap energy, as well as carrier type (n- or p-type), varies between compounds depending on their composition, structure and dimensionality. In this Review, we describe how the tunable electronic structure of TMDs makes them attractive for a variety of applications. They have been investigated as chemically active electrocatalysts for hydrogen evolution and hydrosulfurization, as well as electrically active materials in opto-electronics. Their morphologies and properties are also useful for energy storage applications such as electrodes for Li-ion batteries and supercapacitors.