Halide perovskite like methylammonium lead iodide perovskite (MAPbI3) with its prominent optoelectronic properties has triggered substantial concerns in photocatalytic H2 evolution. In this work, to ...attain preferable photocatalytic performance, a MAPbI3/cobalt phosphide (CoP) hybrid heterojunction is constructed by a facile in situ photosynthesis approach. Systematic investigations reveal that the CoP nanoparticle can work as co‐catalyst to not only extract photogenerated electrons effectively from MAPbI3 to improve the photoinduced charge separation, but also facilitate the interfacial catalytic reaction. As a result, the as‐achieved MAPbI3/CoP hybrid displays a superior H2 evolution rate of 785.9 µmol h−1 g−1 in hydroiodic acid solution within 3 h, which is ≈8.0 times higher than that of pristine MAPbI3. Furthermore, the H2 evolution rate of MAPbI3/CoP hybrid can reach 2087.5 µmol h−1 g−1 when the photocatalytic reaction time reaches 27 h. This study employs a facile in situ photosynthesis strategy to deposit the metal phosphide co‐catalyst on halide perovskite nanocrystals to conduct photocatalytic H2 evolution reaction, which may stimulate the intensive investigation of perovskite/co‐catalyst hybrid systems for future photocatalytic applications.
A methylammonium lead iodide perovskite (MAPbI3)/ cobalt phosphide (CoP) hybrid heterojunction for photocatalytic H2 evolution is synthesized by a facile in situ photosynthesis approach. In this hybrid, CoP nanoparticles can work as a co‐catalyst to not only extract photogenerated electrons effectively from MAPbI3 to improve the photoinduced charge separation, but also facilitate the interfacial catalytic reaction, which further contributes to an enhanced H2 evolution activity.
We develop game-theoretic models to study a supply chain in which two manufacturers supply a product in quality-differentiated brands to a common retailer. The supply chain involves both vertical ...competition between the retailer and manufacturers, and horizontal competition between the two manufacturers. We examine the two manufacturers' pricing timing choices, either early or late, in both the manufacturers Stackelberg and retailer Stackelberg supply chains. The manufacturers are in horizontal competition in an endogenous timing game, with quality being exogenous or endogenous. The impact of the manufacturers' timing of pricing on the profits of the retailer, manufacturers, and supply chain are discussed. We find that when quality is exogenous, in the manufacturers Stackelberg supply chain, either sequential pricing game (either the high-quality manufacturer or low-quality manufacturer moves early) can be the equilibrium. The simultaneous game is the dominant equilibrium in a retailer Stackelberg supply chain, and it results in intensified price competition between the two brands. When quality is endogenous, the simultaneous game is always the dominant equilibrium for both manufacturers Stackelberg and retailer Stackelberg supply chains, and leads to a win-win situation for the retailer and the manufacturers, and the best performance for the entire supply chain. In the simultaneous game with endogenous quality, both the price and quality competitions between the two brands are softened as compared to the case in which the low-quality manufacturer moves first, and intensified as compared to the case in which the high-quality manufacturer moves first. The implications of, and new insights on, the two manufacturers’ choices of pricing timing are also discussed.
•Two manufacturers supply a product in quality-differentiated brands to a common retailer.•Sequential game is preferred in the manufacturers Stackelberg supply chain for exogenous quality.•Imultaneous game is dominant in the retailer Stackelberg supply chain for exogenous quality.•Imultaneous game is always the dominant equilibrium in both types of supply chain.•Implications of and new insights on the two manufacturers' pricing timing choices are discussed.
•The direction and strength of the link between PM2.5 level and their drivers are analyzed.•Spatial regression and geographical detector techniques are used.•A spatial agglomeration effect was ...identified in city-level PM2.5 level.•Population density, industrial structure, industrial dust, and road density increase PM2.5 level.•Trade openness and electricity consumption have no significant effect on PM2.5 level.
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The frequent occurrence of extreme smog episodes in recent years has begun to present a serious threat to human health. In addition to pollutant emissions and meteorological conditions, fine particulate matter (PM2.5) is also influenced by socioeconomic development. Thus, identifying the potential effects of socioeconomic development on PM2.5 variations can provide insights into particulate pollution control. This study applied spatial regression and the geographical detector technique for assessing the directions and strength of association between socioeconomic factors and PM2.5 concentrations, using data collected from 945 monitoring stations in 190 Chinese cities in 2014. The results indicated that the annual average PM2.5 concentrations is 61±20μg/m3, and cites with more than 75μg/m3 were mainly located in North China, especially in Tianjin and Hebei province. We also identified a marked seasonal variation in concentrations levels, with the highest level in winter due to coal consumption, lower temperatures, and less rainfall than in summer. Monthly variations followed a “U-shaped” pattern, with a down trend from January and an inflection point in September and then an increasing trend from October. The results of spatial regression indicated that population density, industrial structure, industrial soot (dust) emissions, and road density have a significantly positive effect on PM2.5 concentrations, with a significantly negative influence exerted only by economic growth. In addition, trade openness and electricity consumption were found to have no significant impact on PM2.5 concentrations. Using the geographical detector technique, the strength of association between the five significant drivers and PM2.5 concentrations was further analyzed. We found notable differences among the variables, with industrial soot (dust) emissions playing a greater role in the PM2.5 concentrations than the other variables. These results will be helpful in understanding the dynamics and the underlying mechanisms at work in PM2.5 concentrations in China at the city level, and thereby assisting the Chinese government in employing effective strategies to tackle pollution.
Amid the social background of China where the Internet has penetrated into every corner of an adolescent's life, we were concerned of the role of Internet usage in influencing the educational gap ...among social classes. We investigated the mediating role of Internet usage preference for entertainment in the relationship between the family socioeconomic status (SES) and the adolescent's academic achievement and explored the moderating role of future orientation in the relationship. A total of 614 junior high school students were recruited to complete a questionnaire survey, including questionnaires for family SES, Internet usage preference, and adolescent future orientation. The results showed that (1) the relationship between family SES and academic achievement was mediated by Internet usage preference for entertainment; (2) the indirect effect was moderated by future orientation, such that the negative association between family SES and Internet usage preference for entertainment was only indicated in adolescents with low future orientation; and (3) the direct association between family SES and Internet usage preference for entertainment was moderated by future orientation.
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•Loofah sponge-derived 3D porous activated carbon is facilely prepared.•Hierarchical pores are constructed in the resulting SAC-x architecture.•SAC-4 exhibits excellent capacity ...performance in the three- and two-electrode systems.•The resulting materials have tremendous potentials for the energy storage applications.
Biomass carbon source is generally cheap, environmentally friendly and readily available in high quality and quantity. In this work, a series of loofah sponge-derived activated carbon (SAC-x) with hierarchical porous structures are prepared by KOH chemical activation and used as electrode materials for supercapacitors. The pore size can be easily controllable by changing the dosage of KOH. The optimized material (SAC-4) exhibits a high specific capacitance of 309.6Fg−1 at 1Ag−1 in the three-electrode system using 6M KOH electrolyte. More importantly, the as-assembled symmetric supercapacitor based on SAC-4 exhibits a high energy density of 16.1Whkg−1 at a power density of 160.0Wkg−1 using 1M Na2SO4 electrolyte. These remarkable results demonstrate the exciting commercial potential of SAC-x for high-performance supercapacitor applications due to their high specific surface area, appropriately porous structure, and the trace heteroatom (O and N) functionalities.
The charge carriers of single‐junction solar cells can be fluently extracted and then collected by electrodes, leading to weak charge carrier accumulation and low energy loss (Eloss). However, in ...tandem solar cells (TSCs), it is a considerable challenge to obtain a balance between the densities of the holes and electrons extracted from the two respective subcells to facilitate an efficient recombination in the interconnecting layer (ICL). Herein, a charge‐carrier‐dynamic management strategy for inorganic perovskite/organic TSCs is proposed, centered on the simultaneous regulation of the defect states of CsPbI1.9Br1.1 perovskite in the front subcell and hole transport ability from the perovskite to ICL. The target hole density on the perovskite surface and the hole loss before reaching the ICL are significantly improved. As a result, the hole/electron density offset in the ICL can be effectively narrowed, leading to a balanced charge carrier recombination, which reduces the Eloss in TSCs. The resulting inorganic perovskite/organic 0.062‐cm2 TSC exhibits a remarkable power conversion efficiency (PCE) of 23.17% with an ultrahigh open‐circuit voltage (Voc) of 2.15 V, and the PCE of the 1.004‐cm2 device (21.69%) exhibited a weak size‐dependence. This charge‐carrier‐dynamic management strategy can also effectively enhance the operational and ultraviolet‐light stabilities of the TSCs.
A charge‐carrier‐dynamic management strategy for inorganic perovskite/organic tandem solar cells (TSCs) is conducted to narrow the hole/electron density offset in the interconnecting layer, which contributes to a balanced charge carrier recombination thus reducing the energy loss of the TSCs. A promising 23.17% power conversion efficiency, an ultrahigh open‐circuit voltage of 2.15 V, and robust operational stability are obtained.
To assess if there is a relationship between residential radon exposure and two lung cancer histological types, small-cell carcinoma (diagnosed in people with a smoking history) and adenocarcinoma ...(the most commonly diagnosed histologic type in people who have never smoked) among males and females in Canada.
With survey data of long-term radon measurements in residential homes, long-term averaged tobacco consumption rates in the units of cigarettes per day per person and long-term averaged age-standardized lung cancer incidence rates at provincial level, simple linear fitting (ANOVA linear regression) was applied in this study to determine the effect on lung cancer induction by smoking and exposure to indoor radon, and to assess if there is a relationship between residential radon exposure and lung cancer histological types.
Lung cancer incidence rates correlate very well with the tobacco consumption rates (P < 0.05). However, females appear to be more likely than males to develop lung cancer at a given amount of cigarette consumption. For both small-cell carcinoma and adenocarcinoma, a statistically significant correlation between incidence rate and mean radon concentration was observed for females, the correlation was much stronger for adenocarcinoma (P = 0.0057) than small-cell carcinoma (P = 0.0483). However, there was no such correlation for males.
It is possible that female non-smokers are more susceptible to radon-induced lung cancer, and the joint effect of radon exposure and tobacco smoking may be worse in female smokers compared to males, such that higher incidence rate of adenocarcinoma among females compared to males were observed in recent decades, even though females never smoked more than males.
Rapid progress in the power conversion efficiency (PCE) of polymer solar cells (PSEs) is beneficial from the factors that match the irradiated solar spectrum, maximize incident light absorption, and ...reduce photogenerated charge recombination. To optimize the device efficiency, a nanopatterned ZnO:Al2O3 composite film is presented as an efficient light‐ and charge‐manipulation layer (LCML). The Al2O3 shells on the ZnO nanoparticles offer the passivation effect that allows optimal electron collection by suppressing charge‐recombination loss. Both the increased refractive index and the patterned deterministic aperiodic nanostructure in the ZnO:Al2O3 LCML cause broadband light harvesting. Highly efficient single‐junction PSCs for different binary blends are obtained with a peak external quantum efficiency of up to 90%, showing certified PCEs of 9.69% and 13.03% for a fullerene blend of PTB7:PC71BM and a nonfullerene blend, FTAZ:IDIC, respectively. Because of the substantial increase in efficiency, this method unlocks the full potential of the ZnO:Al2O3 LCML toward future photovoltaic applications.
Highly efficient polymer solar cells based on nanopatterned ZnO:Al2O3 composite film achieve a peak external quantum efficiency up to 90% and a certified power conversion efficiency of 13.03%. Optical and electrical studies demonstrate enhanced light harvesting due to passivation‐ and dipole‐induced suppression of charge recombination loss and broadband absorption enhancement.
•We investigate the optimal pricing policies for differentiated brands.•Intensified competition between the two manufacturers hurts the manufacturers.•Intensified competition between the two ...manufacturers benefits the retailer.•No dominance among supply chain members leads to the highest profit.•For competing manufacturers, being first to announce price results in lower profit.
We investigate a supply chain in which a retailer is supplied by two manufacturers with differentiated brands, a good brand and an average brand. The customers in the market are segmented based on value and brand preference, namely the customer acceptance of the average brand and the customer surplus for each brand. Both horizontal competition (between the two competing manufacturers) and vertical competition (between the manufacturers and the retailer) are considered through an exploration of different power structure combinations. Multiple-stage game models are developed to examine the impact of different power structures on the pricing decisions and the profits of the manufacturers and the retailer. We find that intensified competition between the two manufacturers hurts the manufacturers and benefits the retailer. No dominance among supply chain members (the two manufacturers and the retailer) leads to the highest profit for the entire supply chain. We also find that for the two competing manufacturers, being first to announce the pricing decision results in lower profit – the second to announce benefits from knowing the rival's price. This explains why rivals prefer not to reveal decisions on prices, bid rates, and contracts, as this information represents bargaining power. The impact of customer acceptance of the average brand is also analyzed.
Ultrasound-guided Erector Spinae Plane Block (ESPB) has been increasingly applied in patients for postoperative analgesia. Its effectiveness remain uncertain. This meta-analysis aimed to determine ...the clinical efficacy of ultrasound-guided ESPB in adults undergoing general anesthesia (GA) surgeries.
A systematic databases search was conducted in PubMed, Embase, and the Cochrane Library for randomized controlled trials (RCTs) comparing ESPB with control or placebo. Primary outcome was iv. opioid consumption 24 h after surgery. Standardized mean differences (SMDs) and risk ratios (RRs) with 95% confidence intervals (CIs) were calculated with a random-effects model.
A total of 12 RCTs consisting of 590 patients were included. Ultrasound-guided ESPB showed a reduction of intravenous opioid consumption 24 h after surgery (SMD = - 2.18; 95% confidence interval (CI) -2.76 to - 1.61,p < 0.00001). Considerable heterogeneity was observed (87%). It further reduced the number of patients who required postoperative analgesia (RR = 0.41,95% CI 0.25 to 0.66,p = 0,0002) and prolonged time to first rescue analgesia (SMD = 4.56,95% CI 1.89 to 7.22, p = 0.0008).
Ultrasound-guided ESPB provides effective postoperative analgesic in adults undergoing GA surgeries.
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