Time filter

Source Type

Guo L.,Fuzhou University | Zhong J.,Fuzhou University | Wu J.,Fuzhou University | Fu F.,Fuzhou University | And 4 more authors.
Analyst | Year: 2011

We here report a novel fluorescent method for the detection of melamine based on the high fluorescence quenching ability of gold nanoparticles. The fluorescence was significantly quenched via fluorescence resonance energy transfer when fluorescein molecules were attached to the surface of gold nanoparticles by electrostatic interaction. Upon addition of melamine, the fluorescence was enhanced due to the competitive adsorption of gold nanoparticles between melamine and fluorescein. Under the optimum conditions, the fluorescence enhancement efficiency [(I - I0)/I0] showed a linear relationship with the concentration of melamine in the range of 1.0 × 10-7 mol L-1∼4.0 × 10-6 mol L-1, and the detection limit was calculated to be 1.0 × 10-9 mol L-1. The proposed method showed several advantages such as high sensitivity, short analysis time, low cost and ease of operation. © 2011 The Royal Society of Chemistry.


Guo L.,Fuzhou University | Guo L.,Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety | Zhong J.,Fuzhou University | Zhong J.,Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety | And 8 more authors.
Talanta | Year: 2010

A simple, rapid, field-portable colorimetric method for the detection of melamine based on melamine-induced color change of label-free gold nanoparticles (Au NPs) was developed in this study. Melamine can induced the aggregation of Au NPs and results in the color change from wine-red to purple, which provided a platform for rapid and field-portable colorimetric detection of melamine. The proposed method can be used to detect melamine in liquid milk and infant formula with a detection limit of 1.0 and 4.2 ppm, respectively, within 30 min by naked eyes observation without the aid of any advanced instrument and the need of any complex pretreatment, and detect as low as 0.15 ppm of melamine in liquid milk and 2.5 ppm of melamine in infant formula with UV-vis-spectroscopy. The proposed method is promising for on-site screening of melamine adulterant in milk products. © 2010 Elsevier B.V.


Cai J.,China Jiliang University | Cai J.,Zhejiang University | Cai H.,Zhejiang University | Cai H.,Fujian Provincial Central Inspection Institute | And 2 more authors.
Nongye Jixie Xuebao/Transactions of the Chinese Society of Agricultural Machinery | Year: 2011

In order to quickly and accurately identify the guidance line in complex environment, a line recognition algorithm based on prior knowledge was proposed. Images were divided into several regions by field range and line characteristic. Both means of full image and region were used to make adaptive threshold of each region. Scanning mode was decided by information of previous image, then noises were filtered and intermediate points were acquired. An improved Hough transformation with search angle limitation and nonuniform sampling was applied to localize guidance line. Finally cross ratio theorem was used to calibrate the parameters. The experimental result showed the method was characterized by robustness and real-time, the average computing time was about 90 ms for each image.


Cai J.-H.,Zhejiang University | Cai J.-H.,China Jiliang University | Zhang G.-X.,Zhejiang University | Cai H.,Zhejiang University | And 3 more authors.
Zhejiang Daxue Xuebao(Gongxue Ban)/Journal of Zhejiang University (Engineering Science) | Year: 2010

A new reconstruction operator based on second-generation connectivity mask was proposed to efficiently utilize the multi-channel information and improve the filtering performance of reconstruction operator. The connectivity mask image, reconstruction mask image and reconstruction marker image are firstly obtained based on different channel information and constrictions. According to the mask-based second-generation connectivity, the proposed operator relabels the connected components in the reconstruction mask image. By partition and clustering, a new connectivity space is formed from the reconstruction mask image. In the new connectivity space, some connected components are selectively reconstructed according to the corresponding regions in the marker image. By flexibly selecting the connectivity mask and the mark image, and effectively utilizing the grads information, color information and multi-channel information, the mask-based reconstruction operator can solve the problem of information restriction of the traditional reconstruction operator.

Loading Fujian Provincial Central Inspection Institute collaborators
Loading Fujian Provincial Central Inspection Institute collaborators