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Light-reflecting characteristics play a crucial role in optically rewritable liquid crystal display (electronic paper). By using a special optimizer software, light-reflecting characteristics of the twisted nematic cell were calculated. The achieved values of the normalized reflection coefficients range within ∼ 0.03 - 0.43, which is comparable or better than other commercial technologies. The calculated contrast ratio of the device is 10 : 1. A 2D image, which can be displayed on the electronic paper was obtained. Comparison of the simulated background color and contrast ratio is very similar with the results, which were obtained in experimental cells of other studies. Our calculations indicate that angular dependence of the reflectance coefficient is almost uniform within a wide range of viewing angles.

Surface-enhanced Raman scattering (SERS), a simple, highly sensitive, and fast analytical method can be used to detect corrosion components on the surface of bronze ware, a difficult problem. The silver mirror reaction is suggested for depositing precious metal nanoparticles on cellulose filter paper in order to create a quick, easy, and low-cost approach for creating SERS substrates. After an 8-minute deposition time, optical microscopy and scanning electron microscopy (SEM) revealed a uniform dispersion of precious metals on cellulose filter paper. To examine the SERS characteristics of the substrate, copper chloride oxide, the main ingredient in the damaging rust of trace bronze ware, was used as the probe molecule. The findings show that cellulose filter paper with a uniform distribution of precious metals achieves the best SERS performance. The flexible substrate enables effective trace analysis of damaging rust on bronze surfaces.

In order to reasonably evaluate the effectiveness of UHF sensor arrangement in online monitoring of partial discharge of bushing, it is necessary to study the electromagnetic wave propagation characteristics of partial discharge UHF in the bushing. In this paper, a three-dimensional model of a real transformer bushing is established, the XFDTD software is used to simulate the raised seat defects and internal capacitive core defects of the bushing, field strength sensors are arranged at different locations inside and outside the bushing, and the propagation process of partial discharge UHF signals leaking from the oil-paper insulated bushing to the external free space is simulated and analyzed. The results show that the time difference between the signals received by the field strength sensors at different locations is not significant and can be neglected in practice. The partial discharge electromagnetic wave signal generated by the bushing elevated seat defect leaks from the upper porcelain sleeve to the external space, and the leaked electromagnetic wave energy is mainly gathered at the upper and lower ends of the upper porcelain sleeve. The partially discharged electromagnetic signal at the capacitor core inside the bushing will propagate along the coaxial waveguide structure formed between the capacitor screens towards the two ends of the capacitor core, the downward propagating electromagnetic wave energy is confined within the elevated seat, the upward propagating electromagnetic wave energy propagates from the top of the upper porcelain bushing to the external space, the leaked electromagnetic wave energy is mainly concentrated at the top of the upper porcelain bushing. The simulation results provide ideas for optimizing the arrangement of external antenna sensors for UHF detection of partial discharges in transformer oil-paper insulated bushings.

This paper reports the use of non destructive, microstrip patch antenna as paper moisture sensor. Microstrip patch antenna is designed to resonate at 2.4GHz. This design is simulated and fabricated on copper clad type FR4 (εr= 4.4) having thickness of 1.6mm. Patch dimension are 27mm × 30mm and substrate dimension is 63mm × 60mm. The microstrip transmission line is used to provide excitation for the antenna. This design for microstrip patch antenna after fabrication showed a resonance at 2.38 GHz on vector network analyzer at S11=-19.38dB with impedance =49Ω. The variations in frequency in relation with water content in the paper is measured using Vector Network Analyzer by placing wet paper on the patch antenna. Moisture content in the paper was found out by taking wet weight and dry weight of the paper. The model of the wet paper is recommended primarily on the basis of water-dry paper reactions, along with the thickness and surface roughness explaining tendencies of the sensitivity graphs. Paper samples of 13 different types, with different GSM values and thicknesses, havingdimensions same as that of the substrate were tested. From the results it is observed that as the moisture content in the paper increases the frequency decreases. The change in frequency with respect to the moisture content is seen to have quadratic relation with moisture. The variations in the frequency are fitted in the form of equations. The calculated %Mwet indicates an error around ±0-4% in the calculated value as compared to the actual value. The response of sensor is almost linear with respect to the references but the coefficients depend non-linearly with the paper dimension.

This experiment initially explored the clean production process of nanocellulose fibrils (NFC) using commercial softwood pulp as raw materials, and selected appropriate biological enzyme pretreatment to prepare NFC1 with a higher concentration. Compared with NFC2 obtained by TEMPO oxidation method, it is found that the diameter of NFC1 obtained by enzymatic pretreatment method (10-30nm) is similar to that of NFC2 (20-30nm). But the length of NFC1 (1-4μm) is much longer than the length of NFC2 (400-600nm). In addition, the influence of two kinds of NFC on the physical strength of paper is also explored. Experimental results show that: NFC1 is better than NFC2 in enhancing the physical strength of paper. And when cationic starch and NFC act synergistically, the enhancement effect is obviously better than using NFC alone or cationic starch alone. When the addition amount of NFC1 is (1.5±0.5)%, the tensile index, burst index, and tear index of the resulting paper increase by (43±3)%, (55±1)%, (37±2), respectively %. When the amount of NFC2 added is (1.5±0.5)%, the paper tensile index is (29±2)%. When the amount of NFC2 added is about (3±1)%, the paper’s bursting index and tearing index growth rate are (29±1)% and (33±1)% respectively.

Determining the optimal clusters can be regarded as a grouping problem that has produced many cluster approach methods in various studies. Each method has provisions that can solve one or more grouping problems in generating information from data set with a number of k being tested. The advantages and disadvantages of each method actually complement to each other in solving the grouping problems. This paper aims to describe the performance of cluster approach methods in determining the optimal clusters through a review by paying attention to the criteria of the problem which is an obstacle to the grouping problem. The results of this review are expected to be a reference for developing the new optimal cluster approach method through possible combinatorial optimization.

The traditional Chinese folk paper-cutting art has a long history. It is a traditional folk art form created by working people to satisfy their spiritual and material pursuits. It originates from life and returns to life. With the pace of the times, folk paper-cutting has undergone an innovative transformation and development through the interweaving, penetration and integration of contemporary design concepts. Through the combination of network big data, it provides a large number of references for modern graphic design decoration and function combination, graphic context inheritance, color language, modeling language, etc.

When partial discharge occurs in the power transformer, the arc can further develop on the oil-paper interface between high and low potentials, and then form a path, resulting in large-area flashover. This will lead to a wide range of insulation damage, insulation failure, equipment shutdown and even large-scale economic losses. For the insulation damage caused by surface discharge of oil paper insulation, relevant scientific research institutions have carried out a large number of experimental studies. However, limited by the test conditions, the research focuses on the small-size model below 50mm, and mostly adopts the test device of uneven electric field. The research on the “large-size“ of the same scale inside the transformer is still blank. In this study, an oil-paper insulation surface discharge test platform with a large size of 50-150mm is built, the electric field conditions at the oil paper interface during the operation of transformers in engineering are simulated, and the surface discharge test of insulating paperboard is carried out by taking the same sample processing means as the engineering. Combined with the test results, a typical design optimization case of setting along surface corner ring to improve the allowable value of along surface discharge field and enhance along surface insulation margin is proposed. It lays a foundation for enriching the transformer oil-paper insulation design parameter system and improving the transformer oil paper insulation performance and operation reliability.

A tapered glass capillary MeV-ion microbeam setup, previously home-developed, was recently upgraded. To check the upgraded microbeam system quality and accuracy, microbeam particle induced X-ray emission (PIXE) mapping of potassium permanganate (KMnO4) solution diffusion in filter paper was carried out to study how the measured solvent diffusion followed the diffusion laws. Two initial boundary conditions and diffusion situations were applied: (1) the paper vertically placed in air with one end soaked in the solution for ten minutes, and (2) the paper horizontally placed on water with the solution dropped at a side of the paper for three minutes. 2-MeV-proton microbeam PIXE analyzed the paper pixel by pixel and the GUPIXWIN software was used to calculate the elemental concentrations in the pixels to map the concentration changes in the pixels as a function of the distance between the pixel position and the origin of the solution. The resulting maps demonstrated the solution diffusions in two cases indeed well following the diffusion laws, a steady-state diffusion dominated process where the elemental concentration was a linear function with the distance but joined by other non-diffusion factors for case 1, and a pure diffusion process where the elemental concentration was an error function with the distance for case 2.

Detection and identification of potassium ion (K+) level in urine is essential for diagnosis of several deseases or for guiding treatments. We have developed a simple, rapid, low cost and naked-eye quantitative method for K+ analysis in urine using a paper-based colorimetric array test strip. The array comprised three sensing elements printed using a wax-printing technique and filled with different amounts of crown ether (4-aminodibenzo-18-crown-6) modified gold nanoparticles (AuNPs). The detection is achieved by measuring the color change (from red to violet) when AuNPs aggregated following crown ether-K+ complexation. Furthermore, the detection sensitivity could be controlled by changing the amount of the crown ether. The strip sensor array based on crown ether modified AuNPs successfully detected K+ level in the ranges of 5-1000 µM by naked eye. Thus, the developed sensor is very simple yet has a potential to be of real use in detecting K+ in real urine samples.