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Visible Light Communication (VLC) has become an effective underwater communication technology due to its advantages such as fast transmission speed and strong confidentiality. When light propagates underwater, it is prone to scattering, resulting in a decrease in the energy of light propagation with the increase of transmission distance. Therefore, improving the responsiveness of the receiving end is the key technology to achieve underwater VLC. This article first designs a new holographic waveguide focusing system for the front end of the detector, which can effectively improve the signal-to-noise ratio of underwater detectors. Then, we construct a low-cost antimony sulfide thin film detector with weak light detection capability. Based on the built VLC system, the experimental results show that the dark current of the receiver detector is only 10-7 A/cm2, with a 3 dB bandwidth of 220 kHz, a response of 0.2 A/W, and an external quantum efficiency of over 70% in the blue green light band. Therefore, the new antimony sulfide thin film detector combined with a holographic waveguide focusing system can achieve weak light detection of visible light, making it a very effective underwater visible light receiving system.

Background With the aggravation of aging trend, the influence of intergenerational support on the health of the elderly has gradually attracted attention, and the absence of spiritual care and life care is an important factor for the occurrence of health problems in the elderly, but there is a lack of scientific evaluation tools to evaluate the cognitive level of old-age care. Objective To develop a Knowledge, Attitude and Practice about Filial Piety Ethics Questionnaires for Offspring and Grandchildren in the process of elderly care, and to test its reliability and validity. Methods From April to July 2021, the first draft of the questionnaire was determined by searching relevant contents in databases such as PubMed, Web of Science, China Knowledge Network and Wanfang Data Knowledge Service Platform, and using the theory of knowledge, attitude and practice and Maslow's hierarchy of needs as the theoretical framework, combined with literature review, national maintenance laws, qualitative interviews, the questionnaire was refined with results of the Delphi expert consensus and pre-survey. From October 2021 to March 2022, 270 subjects from each generation were selected for the formal survey and 50 subjects from the offspring and 38 subjects from the grangchildren were selected for test-retest reliability using the random cluster sampling method. A total of 540 questionnaires were distributed, 270 questionnaires for each generation. A total of 528 valid questionnaires were returned, 264 valid questionnaires for each generation, with a valid return rate of 97.8%. Its reliability and validity were analyzed to determine the final questionnaire entry. Results The Knowledge, Attitude and Practice about Filial Piety Ethics Questionnaires for Offsprings included 3 dimensions and 34 items. Exploratory factor analysis produced 3 factors, with a cumulative variance contribution rate of 64.455%. The content validity of each item ranged from 0.867 to 1.000, and the average content validity of the questionnaire was 0.967. Cronbach's α coefficient was 0.953, split-half reliability was 0.811, and test-retest reliability was 0.987. The Knowledge, Attitude and Practice about Filial Piety Ethics Questionnaires for Grandchildren consisted of 31 items in 3 dimensions. Exploratory factor analysis produced three factors, the cumulative variance contribution rate was 64.641%; the content validity of each item ranged from 0.867 to 1.000, the average content validity of the questionnaire was 0.964; Cronbach's α coefficient was 0.952, split-half reliability was 0.837, and test-retest reliability was 0.991. Conclusion The developed questionnaire has good reliability and validity, and can be used as a research tool to evaluate the current status of filial piety ethic knowledge, attitude and behavior of offsprings and grandchildren in the process of elderly care.

Different from conventional ferromagnetic methods, producing a spin-polarized current through electrical ways in spintronic devices can greatly increase operating speed, reduce power consumption, and improve device integration. Inspired by recent experimental progress on the synthesis of a heptauthrene molecule, we investigate its spin-dependent transport contacted with Au electrodes through first-principles calculations. By applying a gate voltage, the transmission can be switched between completely spin-up and spin-down polarized states, achieving an electrically controlled dual-spin filter. Furthermore, a fine tuning on the spin polarization, between 100% and − 100%, can also be realized, where the transport with any ratio of spin-up to spin-down electron quantities can be realized beyond the traditional devices. The peculiar transmission spectra and their shift are found to play crucial roles, where transmission peaks distribute on both sides of the Fermi level with opposite spin components. Such a spin-polarization modulating effect is found to be robust to the molecule-electrode contacting site, indicating it is an intrinsic feature of such systems. Moreover, the dimension of the device is at the single-molecule level, suggesting great application potential. [ABSTRACT FROM AUTHOR]