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Image encryption is an important and effective technique to protect image security. In this paper, a novel image encryption algorithm combining Julia sets and Hilbert curves is proposed. The algorithm utilizes Julia sets’ parameters to generate a random sequence as the initial keys and gets the final encryption keys by scrambling the initial keys through the Hilbert curve. The final cipher image is obtained by modulo arithmetic and diffuse operation. In this method, it needs only a few parameters for the key generation, which greatly reduces the storage space. Moreover, because of the Julia sets’ properties, such as infiniteness and chaotic characteristics, the keys have high sensitivity even to a tiny perturbation. The experimental results indicate that the algorithm has large key space, good statistical property, high sensitivity for the keys, and effective resistance to the chosen-plaintext attack.

To investigate the activities of daily living (ADL) and influencing factors, this survey study was conducted in Shangrao of Jiangxi. A total of 1087 elderly subjects in a long-term care (LTC) program participated in this study and their physical function, cognitive ability, self-rated health, and chronic disease were recorded during March 2017 and April 2018. The ADL scale was used to evaluate the health status of the elderly. F-test and multiple linear regression showed that the average ADL of the participants was 15.12 ± 17.59. The incidence of visual and verbal impairment was 68.6% and 14.1%, respectively. Over 74% of the elderly had severe cognitive impairment; and the prevalence of chronic disease was 84.5%. Multivariate analysis revealed that age, education, BMI (Body Mass Index), low income, verbal and cognitive ability, visual status, health self-evaluation, and some chronic diseases were related to self-care ability (p < 0.05). In summary, this study revealed that the ADL score is lower in this region and identified several influencing factors. These new findings will be useful for the local government to enhance the current LTC program for the elderly population.

Photomultiplication type near-infrared (NIR) organic photodetectors (OPDs) are constructed with lead phthalocyanine (PbPc) and C 60 acted as the donor and acceptor, respectively. Compared with the PbPc/C 60 planar heterojunction device, the PbPc:C 60 mixed active layer devices show enhanced NIR responses. The optimized mixed active layer device displays an external quantum efficiency (EQE) of 22.8% at 870 nm under zero bias, which is about 45% higher than that of planar heterojunction device. Moreover, it also presents a detectivity in the order of 10 12 Jones and an EQE of 400% under applied bias of −8 V, indicating a photocurrent gain obtained in the device. Although the mixed active layer devices have a lower absorption in the NIR region, the donor: acceptor mixed structure increases the donor/acceptor contact area and forms continuous carrier transport paths, which increases the excitons dissociation efficiency and the photogenerated carriers collection efficiency and hence the response of the devices.

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