Display omitted
•Atomically dispersed zinc anchored with a Zn-NC2 coordination was successfully synthesized, and confirm by HAADF-STEM and XAS.•The atomically dispersed zinc sensor showed 27% ...response toward 1500 ppm ethanol at RT with short response time, excellent selectivity and stability.•DFT calculations revealed the gas-sensing process. Further explained the selectivity through two aspects: type of absorption and change of work function.
Atomically dispersed metal catalysts (AMC) provide superb catalytic performance and 100 % atom utilization. AMC provide an almost perfect solution to the limitations of poor selectivity and high power consumption in semiconductor gas sensor applications. Herein, we report the synthesis of AMC ZnNC materials and their application as highly selective room temperature gas sensors for the first time. Various characterization methods including scanning transmission electron microscopy and X-ray absorption spectroscopy corroborate the presence of atomically dispersed Zn with ZnNC2 coordination. As a sample of AMC for gas detection, the AMC ZnNC2-based sensor has 25 % response to 1500 ppm ethanol (C2H5OH) at room temperature (∼25 °C) with excellent selectivity. Density functional theory calculations revealed that ethanol was chemically absorbed on ZnNC2 by forming a strong Zn-O bond, leading to obvious charge transfer from ethanol to ZnNC2. The sensor response can be attributed to the chemical adsorption of ethanol molecules rather than a redox reaction on the ZnNC2 surface. The approach proposed here should yield similar novel developments in gas sensing.
Electrochemical deposition fabricates a new WMo-oxide film, which exhibits remarkable electrochromic properties after optimizating components.
Display omitted
•New energy levels formed by doped ...tungsten atoms enhances the electron drift velocit remarkably.•Special lamellar structures through electrochemical deposit form more electrochemical kinetic active sites.•Fast electron migration channels due to WOMo bonding.•Tungsten-molybdenum oxide films with excellent performance of switching time and coloring efficiency.
Molybdenum oxide (MoO3) stands out as a predominant electrochromic material, finding extensive applications in sustainable photoelectric devices such as multifunctional smart windows. This study introduces an innovative approach to fabricating electrochromic composite films by doping molybdenum oxide with tungsten atoms through electrochemical deposition on indium tin oxide (ITO) substrates. Electrochemical and optical measurements demonstrate the films' superior performance in terms of switching time and coloring efficiency. Analyses using X-ray photoelectron spectroscopy and transmission electron microscopy suggest the formation of a distinct lamellar structure during the electrodeposition process. Additionally, the incorporation of tungsten atoms appears to facilitate an effective WOMo bonding connection. This introduction of W atoms may create a new doping energy level. The unique lamellar structure enhances the number of electrochemically active sites, while the WOMo coupling acts as a channel for electron migration. Consequently, the switching time decreased from 5.5 s to 3.9 s, and the coloring efficiency increased from 15.47 cm2 C−1 to 40.43 cm2 C−1. Furthermore, the transmittance of the W-doped MoO3 films surpasses that of the pure MoO3 films. Overall, tungsten doping improves the electrochromic properties of MoO3, indicating promising potential for further applications.
Effect of Mo element on the precipitation behavior of nanoscale Cu-rich particles in Cu-bearing low carbon high strength steels was investigated in this work. The addition of 0.82 wt% Mo refined the ...size of grain interior Cu-rich particles (ICRPs) from 12 nm to 8 nm, accompanied by the structure changed from 3R-Cu to 9R-Cu. Mo also inhibited the formation of grain boundary Cu-rich particles (BCRPs) with the size of ∼30 nm. The calculation of phase field method indicated that Mo was repelled from Cu-rich particles and enriched in α-Fe matrix, which suppressed the diffusion of Cu atoms and merger of Cu-rich particles. The measured yield strength of CuMo-bearing steel increased by 87 MPa, mainly due to the refinement of ICRPs. The reduction of BCRPs suppressed the crack initiation and propagation at grain boundaries, which contributed to the increment of absorbed energy at −40 °C by 41J.
The meat grinder with SElf-charged Capacitor and Thyristors circuit is a novel circuit for inductive pulsed power supplies. The energy transfer capacitor is one of the key components in this circuit. ...And its capacitance C and the precharged voltage U C are key parameters worth investigating. The circuit working process and corresponding numerical calculation method are briefly introduced. And the method validity is verified through experiments. Then, the influences of C and U C on circuit performance indices, i.e., the maximum voltage across the main switch V sopm , the secondary current multiplication factor m 2 , the ratio of the maximum capacitor energy over the inductor charging energy η C , and the self-recovery rate of the precharged capacitor voltage k UC , are quantitatively analyzed through parameter sweep. Generally speaking, large C is conducive to lower V sopm ; small C and high U C are conducive to higher m 2 ; small C and low U C are conducive to lower η C and higher k UC . Moreover, the analytical expression of k UC is given. With C and U C elaborately selected, k UC can achieve 100%. In addition, the balance relationship between two contradictory indices V sopm and k UC is obtained by solving a biobjective optimization problem and using the genetic algorithm.
•Interactive heat treatment was used to fabricate functionally graded materials.•Fine Nb-rich carbides generated around the semi-dissolved Laves phases.•Stacking faults and dislocation tangles were ...induced by Nb-rich carbides.•Tensile strength was improve from 512 ± 15 MPa to 602 ± 10 MPa.
In-situ heat treatment (IHT) was introduced in wire arc additive manufacturing (WAAM) process to fabricated Inconel625-high strength low alloy (HSLA) steel functionally graded material (FGM). The graded region with severe Laves phases precipitation was heat treated in 1080℃/1h and 1080℃/2h to alleviate the Laves phases adverse effects. Scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and transmission electron microscope (TEM) were applied to analyze the microstructures of the FGMs. By using IHT, the Laves phases were dissolved, Nb-rich carbides packed with dislocation tangles and stacking faults generated, and the tensile strength along the building direction of the Inconel625-HSLA steel FGM has been improved from 512 ± 15 MPa to 602 ± 10 MPa.
An individual-tree diameter growth model was developed for Cunninghamia lanceolata in Fujian province, southeast China. Data were obtained from 72 plantation-grown China-fir trees in 24 ...single-species plots. Ordinary non-linear least squares regression was used to choose the best base model from among 5 theoretical growth equations; selection criteria were the smallest absolute mean residual and root mean square error and the largest adjusted coefficient of determination. To account for autocorrelation in the repeated-measures data, we developed one-level and nested two-level nonlinear mixed-effects (NLME) models, constructed on the selected base model; the NLME models incorporated random effects of the tree and plot. The best random-effects combinations for the NLME models were identified by Akaike's information criterion, Bayesian information criterion and -2 logarithm likelihood. Heteroscedasticity was reduced with two residual variance functions, a power function and an exponential function. The autocorrelation was addressed with three residual autocorrelation structures: a first-order autoregressive structure AR(1), a combination of first-order autoregressive and moving average structures ARMA(1,1) and a compound symmetry structure (CS). The one-level (tree) NLME model performed best. Independent validation data were used to test the performance of the models and to demonstrate the advantage of calibrating the NLME models.
Reliability, robustness, and interlaboratory comparability of quantitative measurements is critical for clinical lipidomics studies. Lipids’ different ex vivo stability in blood bears the risk of ...misinterpretation of data. Clear recommendations for the process of blood sample collection are required. We studied by UHPLC-high resolution mass spectrometry, as part of the “Preanalytics interest group” of the International Lipidomics Society, the stability of 417 lipid species in EDTA whole blood after exposure to either 4°C, 21°C, or 30°C at six different time points (0.5 h–24 h) to cover common daily routine conditions in clinical settings. In total, >800 samples were analyzed. 325 and 288 robust lipid species resisted 24 h exposure of EDTA whole blood to 21°C or 30°C, respectively. Most significant instabilities were detected for FA, LPE, and LPC. Based on our data, we recommend cooling whole blood at once and permanent. Plasma should be separated within 4 h, unless the focus is solely on robust lipids. Lists are provided to check the ex vivo (in)stability of distinct lipids and potential biomarkers of interest in whole blood. To conclude, our results contribute to the international efforts towards reliable and comparable clinical lipidomics data paving the way to the proper diagnostic application of distinct lipid patterns or lipid profiles in the future.
Display omitted
The electrical wire fire often occurs in the confined space, making the flame spread behavior complex and the risk increase. In this paper, experimental and theoretical study on the flame spread over ...three types of polyethylene (PE) electrical wires under different side-confined distances (0∼40 mm) and currents (0∼60 A) was carried out.The ratios of copper diameter to entire wire diameter were 6mm/10 mm, 8mm/12 mm, and 6mm/12 mm for type I, type II and type III, respectively. The results show that, with the increase of s, the flame width and height, and flame spread rate will firstly increase to the maximum peaks at the position of s = 5 mm with attachment wall effect, and then gradually decrease to the values of the unconfined conditions. And with the increase of current, these parameters will gradually increase to the largest at I = 40 A and then decrease for I = 60 A, as the current effect changes from preheating to dripping acceleration.The firm correlation between preheating length δph and pressure difference ΔP is built, which demonstrates the smallest preheating length is at s = 5 mm with the maximum promotion of heat transfer by gypsum board. On the other hand, the generated Joule heat by the current will enhance the length of preheating, making it proportional to current. Meanwhile, it is found that, the dripping frequency influenced by the dripping mass rate, will increase with the current. The heat transfer components including of the solid conduction heat flux (q˙joule″ and q˙c″), flame heat flux (q˙νf″ and q˙rf″) and gypsum board heat flux (q˙rg″ and q˙νg″) are quantitatively analyzed. Correspondingly, a heat transfer model over flame spread is established, which can well predict the flame spread rate.As the diameter of the wire is relatively small, the controlling heat transfer is the flame convective heat flux q˙νf″ in this research. In addition, it is illustrated that, the heat flux of gypsum board q˙νg″+q˙rg″ will decrease with the increase of copper core diameter from type I of 6 mm to type II of 8 mm.While the solid conduction heat flux of copper q˙c″+q˙joule″ will decrease with the increase of thickness of PE from type I of 2 mm to type III of 3 mm. These findings can well give the understanding of heat transfer of flame spread over electrical wires with the effects of sidewall and current.
The present study sought to determine if the positive association between positive emotions and life satisfaction can be understood as a function of hope in Chinese. Consistent with the ...broaden-and-build model of positive emotions, we tested the hypothesis that positive affectivity, the disposition to experience positive emotions, would be associated with broadening hope agency, building hope pathways, or both, in a sample of 212 Chinese college students. Results examining for bootstrapped mediation testing with multiple mediators indicated that positive affectivity was indirectly associated with life satisfaction through hope agency, but not through hope pathways. In support for partial mediation, however, the association between positive affectivity and life satisfaction remained significant even after including hope components in the model. Some implications of the present findings are discussed.
High energy density makes inductive pulsed power supply (IPPS), a research focus of supplies for electromagnetic launch (EML). However, in existing IPPS topologies, the charging and discharging ...stages of the inductors cannot be separated, so the response time of IPPS can be as long as ten or even tens of milliseconds. For this reason, the real-time closed-loop control of the output current and muzzle velocity based on IPPS is nearly impossible, which might be one of its biggest drawbacks compared to the capacitive pulsed power supply (CPPS). In this article, a novel current maintainable meat grinder (CMMG) circuit capable of fast response for EML applications is proposed, in which the antiparallel diode can provide a current maintaining path. After the inductor completes its charging process, the current can be maintained for a period of time. Thus, the circuit can be in a hot standby state and can be triggered with a very short delay. Subsequently, two commutation methods for the CMMG circuit are explored. The first one is to introduce the inverse current commutation with semiconductor device (ICCOS) branch. In its experiment with an inductance energy of 22 kJ, the circuit maintains 77% of the charging energy in the first 10 ms and is triggered successfully after 28 ms with almost zero response delay. The second method is the superconducting switching technology, based on which the CMMG with self-shutdown circuit is proposed and simulated.
PDF
