Direct observation of significant hot carrier cooling suppression in a two-dimensional silicon phononic crystal

Finding hot carrier cooling suppression in new material structures is fundamentally important for developing promising technological applications. These phenomenona have not been reported for crystalline silicon phononic crystals. Herein, we experimentally design two-dimensional (2D) silicon samples consisting of airy hole arrays in a crystalline silicon matrix. For reference, the determined hot carrier cooling times were 0.45 ps and 0.37 ps, respectively, at probe wavelengths of 1080 nm and 1100 nm. Surprisingly, when the 2D structured silicon possessed the properties of a phononic crystal, significant suppression of hot carrier cooling was observed. In these cases, the observed hot carrier cooling times were as long as 15.9 ps and 10.7 ps at probe wavelengths of 1080 nm and 1100 nm, respectively, indicating prolongation by orders of magnitude. This remarkable enhancement was also observed with other probe wavelengths. The present work presents experimental evidence for hot carrier cooling suppression in 2D silicon phononic crystals and opens opportunities for promising applications

Bibliometric and visual analysis of intraoperative hypotension from 2004 to 2022

BackgroundIntraoperative hypotension (IOH) is a common complication occurring in surgical practice. This study aims to comprehensively review the collaboration and impact of countries, institutions, authors, journals, keywords, and critical papers on intraoperative hypotension from the perspective of bibliometric, and to evaluate the evolution of knowledge structure clustering and identify research hotspots and emerging topics.MethodsArticles and reviews related to IOH published from 2004 to 2022 were retrieved from the Web of Science Core Collection. Bibliometric analyses and visualization were conducted on Excel, CiteSpace, VOSviewer, and Bibliometrix (R-Tool of R-Studio).ResultsA total of 1,784 articles and reviews were included from 2004 to 2022. The number of articles on IOH gradually increased in the past few years, and peaked in 2021. These publications were chiefly from 1,938 institutions in 40 countries, led by America and China in publications. Sessler Daniel I published the most papers and enjoyed the highest number of citations. Analysis of the journals with the most outputs showed that most journals concentrated on perioperative medicine and clinical anesthesiology. Delirium, acute kidney injury and vasoconstrictor agents are the current and developing research hotspots. The keywords “Acute kidney injury”, “postoperative complication”, “machine learning”, “risk factors” and “hemodynamic instability” may also become new trends and focuses of the near future research.ConclusionThis study uses bibliometrics and visualization methods to comprehensively review the research on intraoperative hypotension, which is helpful for scholars to better understand the dynamic evolution of IOH and provide directions for future research

Adoption of Mobile Government Cloud from the Perspective of Public Sector

Mobile cloud computing (MCC) has been widely used in every aspect of our society, bringing both advantages and challenges. However, the adoption of MCC technology is still at an early stage of implementation in the governments. To promote the adoption and diffusion of MCC in the government area, exploring the determinants and influence mechanisms of mobile cloud computing-based government (m-Gov cloud) adoption has become the focus in academic and industry. Based on the technology-organization-environment framework and trust theory at the organizational level, an integrated model including the determinants on the adoption of m-Gov cloud is proposed, and 93 survey samples from China are used to analyzed by partial least squares structural equation modeling (PLS-SEM). The results show that provider competence, organizational readiness, external pressure, and trust of m-Gov cloud have significant effects on m-Gov cloud adoption. Perceived benefit, perceived risk, and provider competence have significant effects on m-Gov cloud trust. The m-Gov cloud trust plays an indirect-only (full) mediation and a complementary (partial) mediation effect between perceived benefit, provider competence, and m-Gov cloud adoption, respectively, while perceived risk has no significant direct and indirect effect on m-Gov cloud adoption. The findings provide a new research perspective and practice insights to promote the implementation of solutions based on the idea of mobile cloud computing

An Empirical Analysis of Open Government Data Platform and Enterprise Innovation Performance

Many countries regard open government data (OGD) as an engine to stimulate innovation and economic value, and establish an effective OGD platform (OGDP) for public to access and utilize data. Many literature discuss OGD-based and data- driven business model, type of data application, new product development and other commercial value creation process, however, there are still lacks of reliable empirical study and lacks of in-depth analysis of impact mechanism of OGDP on enterprise innovation. This paper will use difference-in-difference method to empirically examine causal effect of OGDP on enterprise innovation performance in different areas, and reveal effect mechanism of OGDP on enterprise innovation. The empirical results not only expand the application field of open innovation theory and data-driven research, but also fill the gap about lacks of empirical study on OGDP impact. Meanwhile, the confirmation of the impact relationship and mechanism of OGDP on enterprise innovation will promote the development of OGDP and guide governments to implement OGDP in most countries

User Acceptance of Internet of Vehicles Services: Empirical Findings of Partial Least Square Structural Equation Modeling (PLS-SEM) and Fuzzy Sets Qualitative Comparative Analysis (fsQCA)

Recently, IoV-based services and vehicles have come to the forefront as part of the growing market for the automobile industry. Since IoV-based services and vehicles were introduced, they have been expected to grow rapidly. However, contrary to optimistic expectations for future market growth, the IoV-based services and vehicles market has appeared to hit a roadblock and remains at an early market stage. Therefore, research of the determinants leading to consumers’ intention to accept and purchase IoV-based services and vehicles is significant for either academics or practitioners. Drawing upon the extended unified theory of acceptance and use of technology acceptance model (UTAUT2), the perceived risk theory, and the initial trust model, we developed an integrated conceptual model and explored what and how various determinant antecedent conditions fit together on consumer intention to accept IoV-based services and vehicles. The proposed model and hypotheses were assessed by both symmetric (partial least square structural equation modeling, PLS-SEM) and asymmetric (fsQCA) approaches using online survey datasets with 362 Chinese consumers. The findings suggest that PLS-SEM and fsQCA are complementary analytical techniques providing comparable results. PLS-SEM results indicate that performance expectancy, price value, habit, and initial trust have significant effects on behavioral intention to accept IoV services. Despite other determinants, e.g., effort expectancy, social influence, facilitating conditions, hedonic motivation, and perceived risk, have no significant effect. FsQCA results reveal twelve different configurations of determinants resulting in a high level of behavioral intention to accept IoV services, and eight causal paths equifinally leading to the negation of behavioral intention to accept IoV services. These findings suggest that several conditions that were not significant in PLS-SEM are sufficient conditions when combined with other conditions. This study enriches relevant research studies on IoV-based services acceptance and provides relevant insights and marketing suggestions for incentivizing consumers to accept the IoV-based services

Heteroblastic Foliage Affects the Accumulation of Non-Structural Carbohydrates and Biomass in <i>Pinus massoniana</i> (Lamb.) Seedlings

Pines have heteroblastic foliage (primary and secondary needles) during seedling stage, but how heteroblastic foliage affects carbon storage and biomass accumulation, contributing to seedling quality, is unclear. We investigated the influences of heteroblastic foliage on photosynthetic physiological characteristics, non-structural carbohydrate (NSC) and biomass accumulation in current-year seedlings; the key factors determining biomass accumulation were mainly determined by principal component screening, Spearman correlation, and path analysis. The results indicated that (1) primary needles have high photosynthetic pigments (chlorophyll a and total chlorophyll), net photosynthetic rates (Pn), the potential maximum photochemical efficiency (Fv/Fm), and leaf instantaneous water use efficiency (WUEi), whereas higher non-photochemical quenching (NPQ) suggested that sudden light increases induce the initiation of quenching mechanism in primary needles; additionally, secondary needles had a lower transpiration rate (Tr), limiting stomata (Ls), and light saturation point. (2) Secondary needles promoted soluble sugar (fructose and glucose) increases in leaves compared to that of primary needles and increased the leaf biomass accumulation (from 47.06% to 54.30%), enhancing the overall ability of photosynthetic organs; additionally, secondary needles can enhance the proportion of starch storage in the roots, and NSC accumulation was significantly increasing in the seedling leaves and roots. (3) Photosynthetic pigments (carotenoids, chlorophyll a, and total chlorophyll) had direct positive effects on primary needle seedling (PNS) biomass and promoted biomass by indirectly increasing soluble sugar synthesis in the stems. The Pn was the main physiological factor determining PNS biomass accumulation. In addition, the WUEi, Ls, and NPQ had direct negative effects on PNS biomass accumulation, inhibiting photosynthesis to limit seedling growth. Considering the functional traits in heteroblastic foliage is necessary when assessing different leaf types of Pinus massoniana (Lamb.) seedlings, in particular those threats implicated in light, water, and temperature relations. Our results can be beneficial to guide the establishment of seedling management and afforestation measures

Estimating the Influences of Prior Residual Stress on the Creep Rupture Mechanism for P92 Steel

Creep damage is one of the main failure mechanisms of high Cr heat-resistant steel in power plants. Due to the complex changes of stress, strain, and damage at the tip of a creep crack with time, it is difficult to accurately evaluate the effects of residual stress on the creep rupture mechanism. In this study, two levels of residual stress were introduced in P92 high Cr alloy specimens using the local out-of-plane compression approach. The specimens were then subjected to thermal exposure at the temperature of 650 &deg;C for accelerated creep tests. The chemical composition of P92 specimens was obtained using an FLS980-stm Edinburgh fluorescence spectrometer. Then, the constitutive coupling relation between the temperature and material intrinsic flow stress was established based on the Gibbs free energy principle. The effects of prior residual stress on the creep rupture mechanism were investigated by the finite element method (FEM) and experimental method. A comparison of the experimental and simulated results demonstrates that the effect of prior residual stress on the propagation of micro-cracks and the creep rupture time is significant. In sum, the transgranular fracture and the intergranular fracture can be observed in micrographs when the value of prior residual stress exceeds and is less than the material intrinsic flow stress, respectively

Fast preparation of monolithic immobilized pH gradient column by photopolymerization and photografting techniques for isoelectric focusing separation of proteins

A new method was developed to prepare monolithic immobilized pH gradient (M-IPG) columns in UV-transparent fused-silica capillaries by the 5-min photopolymerization of acrylamide and N,N'-methylenebisacrylamide, followed by the 20-min photografting of the focused ampholine-derived glycidylmethacrylate monomer on the monolithic matrix, by which the preparation time was reduced, and the stability of the formed pH gradient was improved, compared with our previous methods. Using the prepared M-IPG column, the baseline separation of proteins was achieved according to their pIs. Without carrier ampholytes added in the running buffer, the separated components could be detected with high sensitivity by UV at low wavelength

Near-infrared photon upconversion and solar synthesis using lead-free nanocrystals

Near-infrared to visible photon upconversion holds great promise for a diverse range of applications. Current photosensitizers for triplet-fusion upconversion across this spectral window often contain either precious or toxic elements, and have relatively low efficiencies. Although colloidal nanocrystals have emerged as versatile photosensitizers, the only family of nanocrystals discovered for near-infrared upconversion is the highly-toxic lead chalcogenides. Here we report zinc-doped CuInSe2 nanocrystals as a low-cost and lead-free alternate, allowing for near-infrared to yellow upconversion with an external quantum efficiency reaching 16.7%. When directly merged with photoredox catalysis, this system enables efficient near-infrared-driven organic synthesis and polymerization, which in turn solves the issue of reabsorption loss for nanocrystal-sensitized upconversion. Moreover, the broadband light capturing of these nanocrystals allows for very rapid reactions under indoor sunlight. Extending the reach of "solar synthesis" into the near-infrared may realize the century-long dream of conducting high added-value chemical transformations using sunlight