High photoresponse inverted ultraviolet photodectectors consisting of iridium phosphor doped into poly(N-vinylcarbazole) polymeric matrix

Highly sensitive inverted polymer ultraviolet (UV) photodectectors were fabricated by doping a phosphorescent material of bis[2-(4-tertbutylphenyl)benzothiazolato-N,C2′] iridium(acetylacetonate) [(t-bt)2Ir(acac)] into poly(N-vinylcarbazole) (PVK) polymeric matrix. Under the UV-260 nm illumination with an intensity of 0.7 mW/cm2, the device achieved a photocurrent of 11.37 mA/cm2 at −3 V, corresponding to a photoresponse of 15.97 A/W, which is 381% higher than the undoped device. Detailed analysis of photoluminescence, charge carrier transportation and film morphologies of PVK polymer active layers were carried out, and the enhanced UV absorption, formation of the triplet excitons and better charge carrier transport are ascribed to the improved photodectector performance

Achievement of High-Response Organic Field-Effect Transistor NO2 Sensor by Using the Synergistic Effect of ZnO/PMMA Hybrid Dielectric and CuPc/Pentacene Heterojunction

High-response organic field-effect transistor (OFET)-based NO2 sensors were fabricated using the synergistic effect the synergistic effect of zinc oxide/poly(methyl methacrylate) (ZnO/PMMA) hybrid dielectric and CuPc/Pentacene heterojunction. Compared with the OFET sensors without synergistic effect, the fabricated OFET sensors showed a remarkable shift of saturation current, field-effect mobility and threshold voltage when exposed to various concentrations of NO2 analyte. Moreover, after being stored in atmosphere for 30 days, the variation of saturation current increased more than 10 folds at 0.5 ppm NO2. By analyzing the electrical characteristics, and the morphologies of organic semiconductor films of the OFET-based sensors, the performance enhancement was ascribed to the synergistic effect of the dielectric and organic semiconductor. The ZnO nanoparticles on PMMA dielectric surface decreased the grain size of pentacene formed on hybrid dielectric, facilitating the diffusion of CuPc molecules into the grain boundary of pentacene and the approach towards the conducting channel of OFET. Hence, NO2 molecules could interact with CuPc and ZnO nanoparticles at the interface of dielectric and organic semiconductor. Our results provided a promising strategy for the design of high performance OFET-based NO2 sensors in future electronic nose and environment monitoring

Hysteresis mechanism and control in pentacene organic field-effect transistors with polymer dielectric

Hysteresis mechanism of pentacene organic field-effect transistors (OFETs) with polyvinyl alcohol (PVA) and/or polymethyl methacrylate (PMMA) dielectrics is studied. Through analyzing the electrical characteristics of OFETs with various PVA/PMMA arrangements, it shows that charge, which is trapped in PVA bulk and at the interface of pentacene/PVA, is one of the origins of hysteresis. The results also show that memory window is proportional to both trap amount in PVA and charge density at the gate/PVA or PVA/pentacene interfaces. Hence, the controllable memory window of around 0 ∼ 10 V can be realized by controlling the thickness and combination of triple-layer polymer dielectrics

Occupational stress of physicians and nurses in emergency departments after contracting COVID-19 and its influencing factors: a cross-sectional study

BackgroundOccupational stress is one of the major occupational health hazards globally. This study investigated the current situation of and factors influencing the occupational stress of physicians and nurses in emergency departments (EDs) after contracting coronavirus disease (COVID-19).MethodsAn online questionnaire survey was conducted among physicians and nurses in EDs in China between January 5 and 8, 2023. A general descriptive analysis of variables was conducted, the differences in the occupational stress of physicians and nurses in EDs with different characteristics were analyzed using the chi-square test, and factors influencing occupational stress were investigated using generalized ordinal logistic regression.ResultsOf the 1924 physicians and nurses in EDs who contracted COVID-19, 64.71% considered their occupational stress high or very high, with overly intense work as the primary stressor. Those with ≥ 10 years of work tenure, working in tertiary hospitals and with higher professional titles were more stressed, while females, nurses, those with a master’s degree or higher, and those who continued to work after contracting COVID-19 were less stressed. There were differences in the predictors of occupational stress between physicians and nurses.ConclusionChina’s physicians and nurses in EDs had high occupational stress after contracting COVID-19. Attention should be given to the occupational mental health of physicians and nurses in EDs, and training on the prevention and treatment of COVID-19 infection should be strengthened

Tailoring the Dielectric Layer Structure for Enhanced Performance of Organic Field-Effect Transistors: The Use of a Sandwiched Polar Dielectric Layer

To investigate the origins of hydroxyl groups in a polymeric dielectric and its applications in organic field-effect transistors (OFETs), a polar polymer layer was inserted between two polymethyl methacrylate (PMMA) dielectric layers, and its effect on the performance as an organic field-effect transistor (OFET) was studied. The OFETs with a sandwiched dielectric layer of poly(vinyl alcohol) (PVA) or poly(4-vinylphenol) (PVP) containing hydroxyl groups had shown enhanced characteristics compared to those with only PMMA layers. The field-effect mobility had been raised more than 10 times in n-type devices (three times in the p-type one), and the threshold voltage had been lowered almost eight times in p-type devices (two times in the n-type). The on-off ratio of two kinds of devices had been enhanced by almost two orders of magnitude. This was attributed to the orientation of hydroxyl groups from disordered to perpendicular to the substrate under gate-applied voltage bias, and additional charges would be induced by this polarization at the interface between the semiconductor and dielectrics, contributing to the accumulation of charge transfer

Oil-in-water nanoemulsion adhesive system: Preparation by ultrasonic homogenization and its application in 3D direct writing composite energetic materials

Stable and low-particle size nanoemulsions were prepared using ultrasound homogenization. The conditions for preparing low-viscosity nanoemulsions were optimized using Response Surface Methodology (RSM) experimental design. The results showed that the addition of composite surfactants at 1%, an ultrasound amplitude of 35%, an ultrasound time of 4 min, and an ultrasound temperature of 20 °C yielded nanoemulsions with the best particle size and stability. The particle distribution was uniform, and the cold and heat stability were good. Compared with traditional emulsions, the low-viscosity nanoemulsion had better environmental stability, storage stability, and exhibited a phenomenon of self-reducing particle size at 40–55 °C, indicating that the emulsion had good performance under complex environmental conditions. The performance test of composite energetic materials using two types of emulsions as bonding systems showed that the low-viscosity nanoemulsion composite energetic material effectively reduced friction sensitivity, increased detonation velocity, and had better thermal stability and smaller propagation size. The results confirmed that the low-viscosity nanoemulsion perfectly met the requirements of bonding agents for composite energetic materials. This study provides a new approach for bonding agent systems of composite energetic materials and can serve as a new method to meet the special requirements of composite energetic materials

Current situation and needs analysis of medical staff first aid ability in China: a cross-sectional study

Abstract Objectives We aim to understand the current situation of the first aid ability and training needs of Chinese medical personnel to provide a scientific basis for formulating the contents and methods of emergency medical rescue training and thereby improve the first aid level of Chinese medical personnel. Methods A cross-sectional survey was conducted between June 2022 and February 2023 using a two-stage cluster sampling method with a structured questionnaire sent to medical workers in 12 provinces in China. 14,527 questionnaires were included in this study. Data were collected on demographic characteristics, first aid knowledge and skills, and training needs. Variance analysis was used to compare the difference between the first aid ability and training needs of medical staff in different hospitals, and multiple linear regression analysis was carried out to evaluate first aid ability and training needs. Result The study included 6041 patients (41.6%) in tertiary hospitals, 5838 patients (40.2%) in secondary hospitals, and 2648 patients (18.2%) in primary hospitals. There were significant differences in the first aid ability and training needs of medical staff in hospitals of different levels (p < 0.001). The score of first aid knowledge and skills in tertiary hospitals was the highest (209.7 ± 45.0), and the score of training needs in primary hospitals was the highest (240.6 ± 44.0). There was a significant correlation between first aid ability and training needs score (p < 0.001). Multiple linear regression analysis shows that geographic region, age, work tenure, gender, job title, department, professional title, monthly income, and hospital level are the influencing factors of training demand. Conclusion Medical staff in primary hospitals generally have low first aid knowledge and skills and a strong willingness to train. Therefore, it is imperative to strengthen the training of first aid ability and research training strategies. The level of the hospital is closely related to the level of first aid, so it is necessary to recognize the commonalities and differences in medical staff’s demand for first aid knowledge and skills and carry out targeted education and training

Vulnerability factors of snake bite patients in China

Abstract Objective To analyze the vulnerability factors of snakebite patients in China. Methods Multi-stage random sampling was used as the main sampling method and snowball sampling as the auxiliary sampling method. The knowledge, attitude and behavior of snakebite among Chinese residents were investigated. Non-parametric test was used to compare the percentage differences in residents’ knowledge, attitude and behavior of snakebite, and generalized linear regression analysis was used to analyze the influencing factors, and the vulnerability factors of snakebite patients were comprehensively analyzed. Results A total of 6338 subjects were included in this study, of which 68.4% were males, and 58.6% were farmers, workers and service personnel. The median total score of knowledge, attitude, and behavior was 26 (22,36). The patients who were improperly treated after injury were ligation proximal to the affected area (23.43%), squeezing (21.82%), and oral and suction wounds (8.74%). Did not go to hospital due to poverty (1351 cases) and did not receive antivenom (2068 cases). There were 21.32% and 32.63%, respectively. Among 4270 patients injected with antivenom 30.7% were vaccinated within 2 h. Among the patients who went to the hospital for treatment (4987), 75.0% arrived at the hospital within 6 h; Among the 4,761 patients who made emergency calls, 37.4% were treated within 0.5 h. Conclusions Snakebite patients in China have weak knowledge about snakebite, low awareness of medical treatment, lack of correct prevention and emergency treatment measures, dependence on folk remedies, poor housing and so on. In addition, there are low availability of antivenoms and unreasonable distribution of medical resources in some areas of China. Multisectoral and multidisciplinary cooperation should be developed to prevent and control snakebites in order to reduce the burden caused by snakebites