Papers by Author: Lu Hai Li

Abstract: The interaction between vibration and friction exists widely in the mechanical system. In order to research the effect of the vibration amplitude on the contact point friction in the mechanical system, a new apparatus is developed independently to measure the point contact friction influenced by the changing amplitude. The data acquired through the apparatus show that the friction at the contact point decreases with increasing of the amplitude. In terms of theoretical analysis in this paper, the increasing of the amplitude actually reduces the contact area at the point. In addition, the friction at the contact point is proportional to the contact area. So, the friction decreases with the decreasing contact area caused by the increasing amplitude.

Abstract: Granular particles exist widely in the nature. The purpose of this paper is to research the impact interaction between rigid body and particles. The diameter ratio between rigid body and particle has the effect on the impact strength exerted on the rigid body impacting particles. In this paper, the same rigid body impacts respectively the particles with five different diameters. The effect of the diameter ratio is analyzed theoretically according to this simulation experiment. With diameter ratio increasing, the vertical velocity, mechanical energy and momentum of the rigid body increase, and the force exerted on the rigid body decreases.

Abstract: Silver nanoplates, also referred to as nanoprisms or nanodisks, are two-dimensional plasmonic nanostructures that have attracted intensive attention due to their strong shape-dependent optical properties and related applications. In order to obtain the silver nanoplates with high concentration, the liquid-phase reduction method was adopted. Silver nanoparticles colloid was obtained by reducing the high molar concentration of AgNO3 (up to 3.17 M) with the hydrazine hydrate (H4N2 • H2O) as reductant in the presence of polyethylene pyrrole (PVP) as the protectant. 0.5 M Sodium Citrate is introduced into the precursor aqueous which containing AgNO3 and PVP, the molar ratio of PVP to AgNO3 was tuned from 0.64 to 1.5. When molar is 1.5, the mainly particles are silver nanospheres, on the contrary, the nanospheres are transferred into nanoplates as the ratio decreased gradually, until the mainly product are nanoplates. The constituent of the silver nano-clusters was established by performing the Powder X-ray diffraction. The nano-silver dispersion with average diameter is about 113.2 nm were finally deserved. The size distribution of the silver nanoparticles is recorded by the Zeta potential analyzer. Scanning electron microscope (SEM) was used to characterize the morphology of the nano-silver particles. The silver content is about 3%. Nano-silver colloid is obtained and purified by centrifugation and wash with deionized water and ethanol. Then, water-based silver conductive ink is obtained by adding some amount deionized water and additives and adjusted parameters, which could be widely used in printed electronics.

Abstract: This paper provides a novel post treatment method to achieve high conductivity of nano-size silver coatings. Based on the preparation of nano-size conductive ink and conductive circuit, the printed sample and the coated conductive film were treated by series concentrations of silver nitrate solution and hydrazine hydrate solution in this order. The samples were dipped in 1%~20% solutions of silver nitrate and hydrazine hydrate successively, to form the new conductive layer of Ag particles only. It was investigated that the relationship between the thickness of printed and coated layers on photo paper and final conductivity after dipped in two kinds of solutions in turn, which were printed from one to three times and coated by screw (6#). Atomic force microscopy (AFM) was used to characterize the morphologies of as printed and coated samples. The surface sheet resistance of sample was tested by four-probe tester. It was found that when the coated silver conductive ink samples were dipped in 2% silver nitrate solutions and 2% hydrazine hydrate solution at room temperature, the conductivity reaches 0.82Ω/□. The samples with thicker conductive film before dipping need solutions at lower concentration to get high conductivity. The roughness of samples after treatment falls down, as the concentrate of dipping solutions rising. It is therefore considered that the “dip in” method provides an efficient alternative to improve the conductivity of samples.

Abstract: Because of clear image, bright color, high saturation of the color printing on coated paper, the ink-jet printing on coated paper catches more and more people’s eyes. In order to solve the problem of the ink-jet ink (cyan, magenta, yellow and black) on coated paper already developed out, whose yellow ink slants red and gloomy, different dyes are used to produce ink-jet ink. The inks were printed on the R-230 ink-jet printer on matt coated paper. The chromatic aberration is obtained on the basis of the colorimetric values in the ISO 12647-2:1996 eqv GB/T 17934.2-1999. It is found that the aberration of the Y79 is lower and its saturation is higher. The ink is filtered with 0.20 μm filter membrane and it can be used on ink-jet printing. The ink was used to print on the coated paper together with the previous cyan, magenta and black ink already developed out. The colorimetric values were measured and chromatic aberration and saturation is computed. The Color gamut graph of original inks and improved inks combination are made and compared to the standard of the ISO 12647-2:1996. It is found that the problems of hue unjust and gloomy color are improved compared to the previous four colors together. The cyan and magenta still stay away from perfect and it should be improved in future.

Abstract: To achieve a satisfied conductivity of nano-size silver printed circuit, post deal with nano-size silver conductive film was investigated. Based on the preparation of nano-size conductive ink and conductive circuit, the coated conductive film was treated by series concentrations of hydrochloride solutions, and then scanned by laser beam. The influence of resolutions concentration and dipping time were investigated separately. Atomic force microscopy (AFM), fourier transform infrared (FTIR) and four-probe tester, were applied to characterize the different tested samples. It was found that when the coated silver conductive ink samples were dipped in 20% hydrochloride for 60min, 15°C before laser scanning, the conductivity reaches 0.3Ω/□. It is therefore considered that the “dip in” method provide an efficient alternative to improve the conductivity which from nano-size silver ink.

Abstract: Water-based polyurethane forms continuous and dense film after fully drying. Ink is lowly absorbed by PU film, affecting drying rate and color reproduction. In order to improve the absorption of ink on PU film, PU/nano alumina compound was prepared by adding nano alumina in PU and stirring at high speed. PU ink absorption coating was got by being coated on the substrate. The influences of different content of nano alumina to transmittance of coating and solid density of color blocks were researched. The influences of soft and hard segment of PU to image resolution and water resistance were also researched. It can be seen that transmittance reduces when content of nano alumina increases. Droplets spread less when using PU of hard segment and image resolution and solid density are also higher. At the same time, water resistance of solid blocks is much better when printed on PU of hard segment.

Abstract: In order to evaluate the practical application effect of the self-made water-based coated paper inkjet ink and to study the influence factors, their printing performance and the influence of the printed material for printing performance is studied. The drying time of coated paper ink and ordinary water-based inkjet ink are measured and compared. Drying process of ink droplet is recorded by video contact angle tester. It is found that the drying rate of the coated paper ink is higher than the ordinary ink and the diffusion of the ordinary ink is severe. The coated paper ink and ordinary ink are printed, and it is found that the former can get better image detail and color reproduction for the picture of human’s face and inanimate object. The coated paper ink can also obtain a better reproduction of tone levels. Coated paper inkjet ink is printed on different coated papers, and the color densities are measured through red, green and blue color filter. The color strength and hue error are obtained to evaluate the color characteristics on different papers. It is concluded that the coated paper inkjet ink can obtain better color on the Henglian gloss coated paper, Sunbrite gloss coated paper and SPCO matt coated paper.

Abstract: In order to acquire conductive film with high transparency, conductive polymer PEDT: PSS was mixed with some polar dopants and some surfactants. The coating fluid was acquired and coated on the PET film with different coating rods, and conductive film was gotten after drying at some temperature. The conductive mechanism of polymer after doping was introduced. Furthermore, the influenced factors of conductivity were discussed, including different dopants and surfactants as well as dried temperature. It was concluded that DMSO and EG were the best dopants, that surfactants including fluoride or silicon were suited for high conductivity. The sheet resistance of conductive film can be less than 300 Ω/□ when dried at 130 oC, at the same time the transparency at 550 nm is more than 83%. After measuring with AFM, the surface of film was sharp and the surface roughness is 7nm.

Abstract: The manufacture of display device is a complex technology. To reach the flexible display like E-paper, many manufacture process such as driving electrode circuit and transistor must be combined with printing technology. From the information reported, the application of gravure prints technology in organic electronics; off-set printing in EMI film and screen technology in circuit are summarized. The study was more about ink jet print technology. It was described that ink jet was used in OLED (Organic light-emitting diode), OTFT (organic thin film transistor), polymer solar cell/ Flexible organic photovoltaic cell and so on. An OE-A (organic electronics application) roadmap for the charge carrier mobility of semiconductors for organic electronics applications was given. To achieve the printed circuit, the nano silver conductive ink was applied and the ink jet circuit surface was tested by microscopy, the conductive and flexible silver film was with many advantages than screen circuit. It was concluded that the printing electronic will play important roll in the display development.