Qi Feng Chen

Research and Manufacture of Nano-Silver Conductive Ink

Printing electronics technology promotes the application of conductive ink. In this paper, the manufacture of nano-sliver conductive ink is investigated. First, Spherical silver nano-particles were reduced from silver nitrate solution by liquid chemical reduction method, with hydrazine hydrate as reductant and PVP as surface-protection reagent. SEM was used to characterize the morphology of silver powders, and the mean particles size is 62.79 nm. Then, conductive ink was prepared with nano-silver particles made in this research as conductive fillers, polyurethane resin and acrylic resin as binders, and stearic acid as dispersant. In the last, the conductive ink was printed on the PCB substrate by screening printing. After the ink is dried, conductivity, abrasion resistance, and adhesion were tested. The experiment results shows that the order of sheet resistivity magnitude is 10-4Ω•m, the number of rubbing fastness is more than 6000, and the adhesion can be resisted repeatedly to tape tear.

Structural Effect of Thiol-Compounds on the Thiol-Ene Based UV Curable Adhesive

Three thiol-compounds with different functionalities were synthesized through esterification reaction which was prepared by 1, 4-butanediol, trimethylolpropane, and pentaerythritol and 3-mercapto propionic acid respectively. Thiol-compounds and polyurethane-acrylate prepolymer were blended with addition of photo-initiator in certain proportions in order to form polyurethane curing film under UV irradiation. The structure and properties of the thiol-compounds and the polyurethane curing film were characterized by NMR, FT-IR, and TG. The results showed that the thiol-ene addition reaction between the urethane acrylates and the thiol-compounds was preceeded. With the increase of functionality of mercaptopropionic acid ester, the thermal stability improved, and the T-peel strength enhanced. When the moral ratio of urethane acrylates and trimethylolpropane-3-mercapto propionic acid ester was 1:1, the adhesive showed the best mechanical properties and thermal stability with curing time 40s, T-peel strength 88N/m and 50 % mass loss at 369°C, respectively.

Research on Synthesis and Performance of Solvent-Free Aluminum-Plastic Composite Polyurethane Adhesive

A low-viscosity and solvent-free polyurethane adhesive was prepared with mixed polyester, polyether and IPDI as main raw materials. The influences of different moral ratios of polyester and polyether on reaction time, viscosity and water resistance, adhesive strength were researched. The effects of catalysts to adhesive were well discussed. The experimental results showed that polyurethane adhesives composed by mixed polyester and polyether had low viscosity and had better waterproof quality. The adhesives showed the best comprehensive properties when the mole ratio of OHs of polyether to OHs of polyester was 0.3/0.7. Catalysts added to this adhesive could speed the curing reaction, but it reduced the peel strength of the adhesives.

Research on the Infiltrating and Diffusing Model of Ink Droplet in Inkjet Imaging System

The infiltration and diffusion of ink droplet in paper coating have significant influence on the image quality in the inkjet imaging. The flight physical phenomenon of the ink droplet was researched and analyzed according to the hydrodynamic equations of multiphase flow discrete phase in this paper, and the energy distribution of ink droplet before contacting with the paper coating was calculated. Base on studying on the surface structure of paper coating, the mechanism of impact, infiltration and diffusion between ink droplet and paper coating also was researched in this paper from the perspective of energy conversion in the imaging process. The proposed mathematical model consisted of the factors of hydrodynamic characteristics for ink droplet and the physical characteristics of paper coating, we could get the maximum diameter of ink droplet spreading in paper coating through solving the model and obtain viscous loss and energy consumption in infiltration of ink droplet by experiment, and then calculated the average infiltration depth of ink droplet.

A Blind Watermarking Algorithm Using DWT and DCT Techniques for Color Image

In this paper, a robust watermarking technique which combines features of Discrete Wavelet Transformation (DWT) and Discrete Cosine Transformation (DCT) is proposed. Firstly the original color image is converted from RGB space to Lab space. In this technique, DWT is used to decompose the luminance coefficients into various frequency and time scale. The block DCT is applied on DWT coefficients of middle frequency to provide high level of robustness. The encrypted watermark is embedded in it by comparison of the intermediate frequency coefficients. Then the color image is converted from Lab space to RGB space to get the watermarked image. Extracting the watermark does not need the original image and the original watermark, it is a blind watermarking method. Finally, the watermarked image is attacked. Peak signal-to-noise ratio (PSNR) value and the normalized correlation (NC) coefficient value are used to evaluate this technique. Simulation experiments show that the watermark is perceptually invisible, this method can achieve the highest possible robustness without losing the transparency.

A Novel Approach of Edge Detection Based on Gray Correlation Degree and Kirsch Operator

Image edge detection plays an important role in the process of image processing. This article classified the effect of various edge detection algorithms of digital images, mainly through the analysis of characteristics of the commonly used several kinds of classical edge detection operator in the time domain. For the actual image, the edge of the gray scale is sometimes not very clear, and the image also contains noise. A new algorithm of edge detection based on gray correlation degree and Kirsch operator is discussed in the paper. Kirsch operator is the reference sequence. Firstly, calculate the gray correlation degree of each pixel in the image and its neighbors formed eight action sequences and reference sequences, then determine the detection of edges based on gray correlation degree. The results show that this method can more accurately detect the useful information of the edge, and has a certain noise immunity. It is an effective and feasible new edge detection method.

A Hybrid SVD-DCT Watermarking Method Used for Halftone Image

In this letter, a digital watermarking method which combines the singular value decomposition (SVD) and the discrete cosine transform (DCT) is presented. First of all, The Arnold scrambling and the DCT are performed on the watermark and the original image, respectively. The SVD transform is performed on the image when scrambled watermark is embedded, then the watermarked image is formed. Finally, we extract watermark from the image which is handled by halftone screens. The experimental results show that this method can achieve the highest possible robustness without losing the transparency. Also it can anti printing and scanning. All the processes do not require any additional equipment. It will bring new hope to the field of anti-counterfeiting printing with singular value decomposition is applied to the half-tone image area.

UV Curable Thiol-Ene Adhesive for Flexible Packaging Based on CO

An important thiol ester photosensitive monomer COMP (CO-based mercaptopropionate) was prepared via melt polycondensation method using castor oil (CO) and 3-Mercaptopropionic acid (3-MPA). Structure of the thiol-compounds was characterized by FT-IR, 1H-NMR. When the thiol compound was used as photosensitive monomer and polyurethane-acrylate prepolymer was used as main material in UV curable adhesive. The UV curable adhesive showed good curing behaviors and thermal stability with curing time 100s, T-peel strength 3.8N/25mm and shrinkage rate 8%; so the UV curable adhesive could meet the requirements for flexible packaging composite.

Data Dissemination and Visualization Browsing of Digital Map Based on Web

We proposed overall design of the visualization browsing map data in network environment in this paper. And we developed map data flow according to the data structure and attributes of map data base. We programmed one map display control, MapCtrl.ocx, with GUI in the specific implementation. It could browse the map by utilizing map data base and self-designed map symbol base. Furthermore, we detailed the specific process of programming the control and the related techniques, such as component technique, data exchange technique and display technique. We developed a prototype of map data visualization browsing system based on ActiveX in network environment, which could achieve several functions such as browsing vector graphics of map data on internet, operation and simple query and analysis.

Research on the Relationship between Ink Permeability and Dot Gain of Different Paper

In order to research the relationship between ink permeability and dot gain of different paper, four kinds of coated paper and two kinds of printing paper were chosen. Ink marks method was used to measure ink permeability of four kinds of coated paper and two kinds of common printing paper. After the ink marks were printed on each of the six kinds of paper, the length of them were measured, then the reciprocal of the ink marks length was multiplied by 1000 to obtain the value of the ink permeability. Inkjet printer was also used to print yellow GATF step-wedge simulating offset printing on the six kinds of paper, then using an optical densitometer to measure the dot gain. Conclusion shows that non-coated paper is higher in permeability than coated paper, which results in high percentage of dot gain.