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Xinhua Zeng

Bio: Xinhua Zeng is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Optical fiber & Silver nanoparticle. The author has an hindex of 6, co-authored 13 publications receiving 126 citations. Previous affiliations of Xinhua Zeng include University of Technology of Troyes.

Papers
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Journal ArticleDOI
TL;DR: The present paper reports on the spatially controlled synthesis of silver nanoparticles (NPs) and silver nanowires by photosensitized reduction by direct photogeneration and a photochemically assisted procedure allowing silver to be deposited at the surface of a polymer microtip.
Abstract: The present paper reports on the spatially controlled synthesis of silver nanoparticles (NPs) and silver nanowires by photosensitized reduction. In a first approach, direct photogeneration of silver NPs at the end of an optical fiber was carried out. Control of both size and density of silver NPs was possible by changing the photonic conditions. In a further development, a photochemically assisted procedure allowing silver to be deposited at the surface of a polymer microtip was implemented. Finally, polymer tips terminated by silver nanowires were fabricated by simultaneous photopolymerization and silver photoreduction. The silver NPs were characterized by UV–visible spectroscopy and scanning electron microscopy.

60 citations

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TL;DR: The ability to manufacture a reference tapered fiber lens with high symmetry at sub-wavelength scale with a wide range of geometry control is demonstrated, either for the length from several hundred nanometers to several hundred microns, or for the curvature radius on the endface of a single mode fiber.
Abstract: In numerous applications of optical scanning microscopy, a reference tapered fiber lens with high symmetry at sub-wavelength scale remains a challenge. Here, we demonstrate the ability to manufacture it with a wide range of geometry control, either for the length from several hundred nanometers to several hundred microns, or for the curvature radius from several tens of nanometers to several microns on the endface of a single mode fiber. On this basis, a scanning optical microscope has been developed, which allows for fast characterization of various sub-wavelength tapered fiber lenses. Focal position and depth of microlenses with different geometries have been determined to be ranged from several hundreds of nanometers to several microns. FDTD calculations are consistent with experimental results.

14 citations

Journal ArticleDOI
TL;DR: A rapid route for fabricating silver nanoparticles at the end of an optical fiber using a fiber integrated plasmon-based sensor and the effect of the refractive index of different solvents on the extinction spectra is explored.
Abstract: We explore a rapid route for fabricating silver nanoparticles (NPs) at the end of an optical fiber. The size and number of silver NPs can be controlled by varying the exposure doses. The effect of the refractive index of different solvents on the extinction spectra have been studied as a proof of concept of a fiber integrated plasmon-based sensor.

13 citations

Journal ArticleDOI
TL;DR: In this paper, the authors developed an approach for the fast and accurate determination of organophosphate pesticides by combining surface-enhanced Raman scattering (SERS) technology with chemometric methods.
Abstract: We have developed an approach for the fast and accurate determination of organophosphate pesticides by combining surface-enhanced Raman scattering (SERS) technology with chemometric methods. We measured the SERS spectra of three pesticides (methyl parathion, edifenphos and ethyl paraxon) and then processed the spectra using the following pre-processing algorithms: baseline subtraction; Savitzky–Golay first derivative, standard normal variate variance (SNV) transformation and multiplicative scatter correction. Principal components analysis and non-negative matrix factorization were subsequently adopted to obtain the main features of the spectra. The data were then used to develop classification models by support vector machines and random forest (RF) regression and the discrimination performance was evaluated through a five-fold cross-validation method. The experiments showed that the baseline subtraction method can perfectly eliminate the fluorescence background and baseline drift. Principal components analysis greatly shortens the training time on the premise of maintaining classification accuracy, although non-negative matrix factorization gives poorer results. SNV can improve the discriminant accuracy up to 4%, except for the use of non-negative matrix factorization, but multiplicative scatter correction and the first derivative method have a negative effect. The classification model of the highest accuracy (99.79%) is built by support vector machines with the spectra processed by SNV and principal components analysis; and the training process takes 1115 s. The training time (81 s) of the RF model developed with the spectra processed by SNV is much shorter than the former method, although the accuracy is similar. The classification accuracy of the model built with RF and different data always maintains a high level, suggesting that RF has excellent robustness. These results show that the most suitable method for the determination of organophosphate pesticides is a combination of SERS spectrometry and RF with SNV.

12 citations

Journal ArticleDOI
TL;DR: A novel route to directly integrate an array of microlenses at the extremity of an optical fiber bundle based on photopolymerization at the end of the fiber is presented.
Abstract: We present a novel route to directly integrate an array of microlenses at the extremity of an optical fiber bundle The method is based on photopolymerization at the end of the fiber The method is based on the control of exposure dose and volume of the deposited droplet of photopolymerizable formulation Optical properties of the integrated microlenses are discussed on the basis of FDTD calculations

11 citations


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Journal Article
TL;DR: In this paper, the authors review what is known about nanocrystal growth and outline strategies for controlling it, and present a review of the current state-of-the-art in this area.
Abstract: Colloidal nanocrystals are nanometer-sized, solution-grown inorganic particles stabilized by a layer of surfactants attached to their surface. The inorganic cores exhibit useful properties controlled by composition as well as size and shape, while the surfactant coating ensures that these structures are easy to fabricate and process. It is this combination of features that makes colloidal nanocrystals attractive and promising building blocks for advanced materials and devices. But their full potential can only be exploited if we achieve exquisite control over their composition, size, shape, crystal structure and surface properties. Here we review what is known about nanocrystal growth and outline strategies for controlling it.

185 citations

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TL;DR: This review presents a broad overview of strategies for patterning the flat tip of an optical fiber, which include self-assembly, numerous lithographies, through-fiber patterning, hybrid techniques, and strategies for mass manufacture.
Abstract: The flat tip of an optical fiber is a unique and unconventional platform for micro and nanotechnologies The small cross-section and large aspect ratio of the fiber provide an inherently light-coupled substrate that is uniquely suited to remote, in vivo and in situ applications However, these same characteristics challenge established fabrication technologies, which are best suited to large planar substrates This review presents a broad overview of strategies for patterning the flat tip of an optical fiber Techniques discussed include self-assembly, numerous lithographies, through-fiber patterning, hybrid techniques, and strategies for mass manufacture, while the diverse applications are discussed in context throughout

180 citations

Journal ArticleDOI
TL;DR: In this article, solid-state thermal decomposition route was applied for synthesis of Ag and Ag2O nanoparticles of new precursor [Ag(Hsal)] for the first time, and the results showed that pure cubic Ag and hexagonal Ag 2O could be obtained after annealing at 400°C for 3h in an Ar gas and in an air, respectively.

129 citations

Journal ArticleDOI
TL;DR: Silver nanoparticles have been successfully prepared with a simple and "green" chemical reduction method and triple helical schizophyllan (SPG) was used for the first time as reducing and stabilizing agents, leading to good dispersion of Ag-NPs with a diameter of 6 nm within the biopolymer matrix.

94 citations

Journal ArticleDOI
TL;DR: An eco-friendly chemical method was successfully used for the preparation of hyaluronan fibers containing silver nanoparticles (AgNPs), which were confirmed by transmission electron microscopy (TEM),X-ray diffraction (XRD), two-dimensional X-ray scattering (2D SWAXS), UV/Vis spectroscopy, inductively coupled plasma optical emission spectrometry (ICP OES) and scan electron microscopes (SEM).

93 citations