Creep and relaxation characteristics of stem for rice seedlings grown in plastic cell tray were studied by static tensile testing, in order to determine the relationship between characteristic parameters (rheological model parameters, stress components and strain components) and test levels (stress levels and strain levels). Rice seedling stem specimen used in the test was 40 mm in length. And the applied test values for the creep and relaxation test ranged from 1.0-3.0 MPa and 1.5%-3.5%, respectively, each for 5 levels. The results indicated that elastic modulus in the creep and relaxation model was not affected by test levels. However, except that viscosity coefficient η kv was a constant and η m1 decreased with the increase of test levels, other viscosity coefficient and rheological time nonlinearly increased as the test levels increased. And strain components in the creep model and stress components in the relaxation model significantly increased as the test levels increased.

A full-color display consisting of red and green photoluminescence cadmium-free quantum dots (QDs) as the color conversion material and excited by a 68 × 68 blue micro-LED flip chip array mounted on an active-matrix driving board was completed in this study. The QD photoresist (QDPR) lithography technology was reported in detail, and it has been proven to be a stable process route. The suitable thickness of 12 ± 1 µ m of the QDPR and black matrix was proposed to reduce the light cross talk between different sub-pixels. The thickness of the common color filter of 1–2 µm was made successfully between the quantum dot film and the cover glass, which can greatly reduce the leakage of blue backlight and decrease the quantum dots excitation by the ambient light, as well as improve the color gamut and color purity of the display panel. In addition, the high red and green light conversion efficiency reaches up to 78.1% and 296.5%, respectively, and the screen display can reach 98.8% NTSC on the CIE 1931 chromaticity. Representative RGB monochromatic pictures were displayed successfully and ≤ 0.04 viewing angle deviation of the display was measured precisely.

No abstract

No abstract

Silicon piezoresistive pressure sensors can only operate below 125°C due to the leakage current of the PN junction. However, SOI high temperature pressure sensors use SiO2 for full dielectric isolation to solve this problem. At present, SOI high temperature pressure sensors mostly use lead bonding package structure, with gold wire to lead the electrical signal and silicone oil as the protection medium, but the working temperature of silicone oil is limited to about 150?. In this paper, the leadless package structure is designed by using pressure conduction on the back side of the chip and replacing the gold wire with conductive silver paste, and the materials and dimensions of the leadless package structure are determined. The reliability of the leadless package structure was verified by finite element analysis, and the results showed that the thermal stress caused by high and low temperature cycles in the leadless package is very small and does not affect the sensitivity of the pressure-sensitive chip. The size of the leadless package structure was optimized by Taguchi orthogonal method, and the maximum thermal stress was effectively reduced. Also, the key factors affecting the thermal stress of the leadless package in the package structure were identified by the variance number analysis method. The electrical signal conduction of the pressure sensor is achieved by a silver paste sintering process, and the data show that the sensitivity of the pressure sensor is 30.82 mV/MPa with a nonlinearity of less than 0.4% FS.