ABSTRACT
For traditional wide-bandgap semiconductor materials, a high-temperature process is unavoidable for improving crystallization quality, so the substrate of the device is greatly limited. In this work, zinc-tin oxide (a-ZTO) amorphous oxide processed by the pulsed laser deposition method was utilized as the n-type layer, which exhibits considerable electron mobility and optical transparency, and can be deposited at room temperature. At the same time, by combining p-type CuI grown by the thermal evaporation method, a vertically structured ultraviolet photodetector based on CuI/ZTO heterojunction was obtained. The detector demonstrates self-powered properties, with an on-off ratio exceeding 104, and rapid response with a rise time of 2.36 ms and a fall time of 1.49 ms. Also, the photodetector shows long-term stability with 92% retention after 5000 s cyclic lighting and maintains reproducible response in frequency dependence measurement. Furthermore, the flexible photodetector on poly(ethylene terephthalate) (PET) substrates was constructed, exhibiting fast response and durability in the bending state. This is the first time that the heterostructure based on CuI has been applied in the flexible photodetector. The excellent results indicate that the combination of amorphous oxide and CuI has the potential for ultraviolet photodetectors, and will broaden the application range of high-performance flexible/transparent optoelectronic devices in the future.
ABSTRACT
To address the increasing labor cost of resin tapping, more efficient methods for resin tapping need to be developed. This study aimed to evaluate the features of resinosis as affected by stimulant pastes in Pinus elliottii × P. caribaea, which is also one of the predominant resin-producing species hybrids in South China. The resin yields and resin compositions were assessed in 33 P. elliottii × P. caribaea F1 families, with the application of four kinds of chemical stimulants, potassium (K2SO4) paste, naphthalene acetic acid (NAA) paste, benzoic acid (BA) paste and 2-chloroethylphosphonic acid (CEPA) paste. Our results showed that all four pastes significantly increased the resin yield by at least 20% at each tapping, and 3- to fivefold increases were detected at the beginning of each year. The correlations between resin yield and growth at each tapping ranged from uncorrelated to moderately positively correlated, indicating that resin yield was mostly but not always determined by tree size. The concentration of each resin component did not change with the stimulant applications. In P. elliottii × P. caribaea, selecting a larger tree diameter at breast height and employing the chemical stimulants at the first several tapping rounds are efficient tapping procedures. Moreover, the K2SO4-based stimulant can be recommended considering its promoting effects on resin yield and the low cost of the chemicals required to produce it.
Subject(s)
Pinus , China , Humans , Resins, PlantABSTRACT
In this study, a novel asymmetric image encryption scheme based on the Rivest-Shamir-Adleman (RSA) algorithm and Arnold transformation is proposed. First, the asymmetric public key RSA algorithm is used to generate the initial values for a quantum logistic map. Second, the parameters of the Arnold map are calculated. Then, Arnold scrambling operation is performed on the plain image to achieve the rough hiding of image information. Third, each row and each column of the image are taken as different units respectively and then exclusive-OR (XOR) diffusion is applied. Finally, the generated keystream is used to perform an end-to-start cyclic modulo diffusion operation for all rows and columns to produce the final cipher image. In addition, the keystream is related to the plain image, which can enhance the ability to resist chosen plaintext attack and known plaintext attack. The test results also show that the proposed encryption algorithm has strong plain sensitivity and key sensitivity.
