Objective To introduce the structure and operating principle of a laser optometer for dark focus(DF). Methods Infrared and vernier means were used in the examination of dark focus. The stability, relationship between dark focus and refractive error were studied. Results The laser optometer was proved to be a reliable instrument with fine stability and good repeatability. Conclusion The laser optometer for dark focus can be used for further study relating to the aviation vision.

With transdermal absorption speed constant as index, the percutaneous osmosis experiments were carried out by orthodox design method to study the preparation process of EVA membrane.The results indicate that the best preparation process of EVA membrane is:10% EVA 36,dissolved by chloroform without the addition of plasticizer, expanding the membrane at the thickness of 0 5 ?m, dried at 80℃ for 6 hours. The membrane is with good releasing-control activity under the above condition.

Objective:To understand the mediating role of resourcefulness between perceived stress and depression in primary caregivers of stroke patients.Methods:The primary caregivers of 311 inpatients with stroke in three Class Ⅲ Grade A hospitals in Yinchuan from December 2020 to August 2021 were selected by convenience sampling and investigated with the general information form, Resourcefulness Scale (RS) , Chinese Perceived Stress Scale (CPSS) and Self-Rating Depression Scale (SDS) . SPSS 25.0 and PROCESS were used to analyze the relationship between the three, and to explore the mediating role of resourcefulness between perceived stress and depression in the primary caregivers of stroke patients.Results:In this study, 311 questionnaires were distributed, 311 questionnaires were recovered, and 308 questionnaires were valid. The primary caregivers of stroke patients scored (24.98±6.38) for perceived stress, (83.98±12.85) for resourcefulness, and (44.35±8.40) for depression. Resourcefulness was negatively correlated with perceived stress and depression scores ( r=-0.313, -0.317; P <0.01) , and perceived stress was positively correlated with depression ( r=0.425, P<0.01) . The Bootstrap method further validated that resourcefulness played a partial mediating role between perceived stress and depression, and the mediating effect accounted for 14.95% of the total effect. Conclusions:Resourcefulness is a mediating variable between the perceived stress and depression of the primary caregivers of stroke patients, and resourcefulness plays a partial mediating role between perceived stress and depression.