Colloidal suspensions of plasmonic nanoparticles (NPs) are a well-established tool for biomedical applications and enhanced spectroscopy because of their strong optical response.The specific response is greatly depend...Colloidal suspensions of plasmonic nanoparticles (NPs) are a well-established tool for biomedical applications and enhanced spectroscopy because of their strong optical response.The specific response is greatly dependent on the NP shape.The strong optical activity of chiral NPs has created special interest but fabrication of chiral NPs in solution remains challenging.Here,we present an approach whereby three-dimensional (3D) chiral Au nano-hooks,fabricated with the parallel hole-mask colloidal lithography (HMCL) method,can be lifted off from a glass substrate in a controllable manner by using a combined treatment with oxygen plasma oxidation and a reduction step in solution.This method has the advantage of being based on established techniques and not requiring strong acids or complex substrates as in etching based approaches.We furthermore demonstrate the integration of the hook NPs into reversibly cross-linked hydrogels inspired by mussel catechol chemistry but containing an oxidation resistant catechol analogue grafted onto poly(allylamine) crosslinked by coordination of Al^3+ and how this facilitates the remote analysis of hydrogel microenvironment,e.g.the water content.The suspended particles are promising candidates for optically active surface-enhanced Raman spectroscopy (SERS),asymmetric photo catalysis or aggregation sensing.The integration into hydrogels to produce functional hydrogels holds benefits for applications of metamaterials in optics,sensing or activation in environmental remediation or drug delivery.展开更多
Electrochemical machining(ECM) is an important machining technique for the aeronautical manufacturing industry. Through-mask ECM is a form of ECM for machining metal parts with a hole array. In order to extend the mac...Electrochemical machining(ECM) is an important machining technique for the aeronautical manufacturing industry. Through-mask ECM is a form of ECM for machining metal parts with a hole array. In order to extend the machining area, a serpentine flow channel with multiple curves was used for through-mask ECM. With the extension of the flow channel, ensuring a machining consistency along the flow channel has been a challenge. The electrolyte conductivity is the main factor affecting the machining consistency. To analyze the change rules of the electrolyte conductivity, variations in the bubble rate and the temperature of the electrolyte in the electrolyte flow were explored under different power sources. Results indicate that pulse-power machining can reduce variations in the bubble rate and the temperature in the serpentine flow channel, and then the electrolyte conductivity can be stabilized within a very small range. Experiments using through-mask ECM were conducted in two types of power sources. Experimental results support the importance of pulse-power machining. A 14×28 hole array with a 2.5 mm diameter was fabricated by a pulsed power source. The aperture deviation of the hole array is less than 0.05 mm, and the roundness deviation is less than 15 lm when fabricated with pulse machining.展开更多
Despite one-dimensional （1D） semiconductor nanostructure arrays attracting increasing attention due to their many advantages, highly ordered TiO2 nanorod arrays （TiO2 NR） are rarely grown in situ on Ti substrates....Despite one-dimensional （1D） semiconductor nanostructure arrays attracting increasing attention due to their many advantages, highly ordered TiO2 nanorod arrays （TiO2 NR） are rarely grown in situ on Ti substrates. Herein, a feasible method to fabricate TiO2 NRs on Ti substrates by using a through-mask anodization process is reported. Self-ordered anodic aluminum oxide （AAO） overlaid on Ti substrate was used as a nanotemplate to induce the growth of TiO2 NRs. The NR length and diameter could be controlled by adjusting anodization parameters such as electrochemical anodization voltage, anodization time and temperature, and electrolyte composition. Furthermore, according to the proposed NR formation mechanism, the anodized Ti ions migrate and deposit in the AAO nanochannels to form Ti（OH）4 or amorphous TiO2 NRs under electric field, owing to the confinement effect of the template. Photoelectrochemical tests indicated that, after hydrogenation, the TiO2 NRs presented higher photocurrent density under simulated sunlight and visible light illuminations, suggesting their potential use in photoelectrochemical water splitting, photocatalysis, solar cells, and sensors.展开更多
文摘Colloidal suspensions of plasmonic nanoparticles (NPs) are a well-established tool for biomedical applications and enhanced spectroscopy because of their strong optical response.The specific response is greatly dependent on the NP shape.The strong optical activity of chiral NPs has created special interest but fabrication of chiral NPs in solution remains challenging.Here,we present an approach whereby three-dimensional (3D) chiral Au nano-hooks,fabricated with the parallel hole-mask colloidal lithography (HMCL) method,can be lifted off from a glass substrate in a controllable manner by using a combined treatment with oxygen plasma oxidation and a reduction step in solution.This method has the advantage of being based on established techniques and not requiring strong acids or complex substrates as in etching based approaches.We furthermore demonstrate the integration of the hook NPs into reversibly cross-linked hydrogels inspired by mussel catechol chemistry but containing an oxidation resistant catechol analogue grafted onto poly(allylamine) crosslinked by coordination of Al^3+ and how this facilitates the remote analysis of hydrogel microenvironment,e.g.the water content.The suspended particles are promising candidates for optically active surface-enhanced Raman spectroscopy (SERS),asymmetric photo catalysis or aggregation sensing.The integration into hydrogels to produce functional hydrogels holds benefits for applications of metamaterials in optics,sensing or activation in environmental remediation or drug delivery.
文摘针对现有深度图像增强算法存在边界保留特性差的问题,提出梯度掩模导向联合滤波(gradient mask guided joint filter,GMGJF)算法。利用深度图像进行Sobel梯度变换获取边界方向信息,利用深度图像空洞区域生成空洞掩模,再以边界方向和空洞掩模为导向联合彩色图像对深度图像进行迭代高斯滤波和空洞填充。实验结果表明,GMGJF算法的PSNR(peak signal to noise ratio)、SSIM(structural similarity index measure)比IMF(iterative median filter)、GF(guided filter)、JBF(joint bilateral filter)算法的PSNR、SSIM至少提高了3.50%和1.07%,不仅去噪能力、空洞填充能力最强,而且边界特征保持最好,有利于深度图像的特征提取与目标识别。
基金supported financially by the National Natural Science Foundation of China(No.51535006)
文摘Electrochemical machining(ECM) is an important machining technique for the aeronautical manufacturing industry. Through-mask ECM is a form of ECM for machining metal parts with a hole array. In order to extend the machining area, a serpentine flow channel with multiple curves was used for through-mask ECM. With the extension of the flow channel, ensuring a machining consistency along the flow channel has been a challenge. The electrolyte conductivity is the main factor affecting the machining consistency. To analyze the change rules of the electrolyte conductivity, variations in the bubble rate and the temperature of the electrolyte in the electrolyte flow were explored under different power sources. Results indicate that pulse-power machining can reduce variations in the bubble rate and the temperature in the serpentine flow channel, and then the electrolyte conductivity can be stabilized within a very small range. Experiments using through-mask ECM were conducted in two types of power sources. Experimental results support the importance of pulse-power machining. A 14×28 hole array with a 2.5 mm diameter was fabricated by a pulsed power source. The aperture deviation of the hole array is less than 0.05 mm, and the roundness deviation is less than 15 lm when fabricated with pulse machining.
基金Thanks for the financial support of the National Natural Science Foundation of China （Nos. 21303227, 21573259, and 51403220）, Qingdao science and tech- nology plan application foundation research project（No. 14-2-4-60-JCH） and the ＂Hundred Talents Pro- gram＂ of Chinese Academy of Sciences （D. A. W.）.
文摘Despite one-dimensional （1D） semiconductor nanostructure arrays attracting increasing attention due to their many advantages, highly ordered TiO2 nanorod arrays （TiO2 NR） are rarely grown in situ on Ti substrates. Herein, a feasible method to fabricate TiO2 NRs on Ti substrates by using a through-mask anodization process is reported. Self-ordered anodic aluminum oxide （AAO） overlaid on Ti substrate was used as a nanotemplate to induce the growth of TiO2 NRs. The NR length and diameter could be controlled by adjusting anodization parameters such as electrochemical anodization voltage, anodization time and temperature, and electrolyte composition. Furthermore, according to the proposed NR formation mechanism, the anodized Ti ions migrate and deposit in the AAO nanochannels to form Ti（OH）4 or amorphous TiO2 NRs under electric field, owing to the confinement effect of the template. Photoelectrochemical tests indicated that, after hydrogenation, the TiO2 NRs presented higher photocurrent density under simulated sunlight and visible light illuminations, suggesting their potential use in photoelectrochemical water splitting, photocatalysis, solar cells, and sensors.
