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Achieving low cost at high performance is difficult for direct ammonia microfluidic fuel cell (DAMFC) as a portable clean energy conversion device. In this work, a DAMFC with Ni nanoparticles anode and catalyst-free cathode is proposed to realize low cost and high performance of the fuel cell at room temperature. Due to the uniform distribution and spherical geometry of the Ni nano-catalyst, the Ni anode prepared by cyclic voltammetry owns excellent activity of ammonia oxidation. Meanwhile, sodium persulfate having strong oxidizing properties is selected as the oxidant, resulting in catalyst-free carbon paper by cyclic voltammetry treatment directly used as the cathode to greatly reduce the cost of the DAMFC. By optimizing the electrodeposition conditions of Ni electrode and the operating conditions of fuel cell, the DAMFC achieves optimal performance. The maximum power density is 8.43 mW cm−2 and the limiting current density is 78.58 mA cm−2, which is higher than that of most previously reported low-temperature ammonia fuel cells. Moreover, the fuel cell has good stability. Therefore, it proves that a DAMFC with Ni nanoparticles anode and catalyst-free cathode is an effective method to realize low cost and high performance of the ammonia fuel cell at room temperature. [Display omitted] • A low-cost and high-performance ammonia microfluidic fuel cell is proposed. • The spherical nickel nanoparticle catalyst with uniform dispersion is prepared. • Sodium persulfate with strong oxidizing property is selected as oxidant. • The effect of reactant concentration on cell performance is discussed. • The introduction of sodium persulfate removes noble-metal catalyst and improves cell performance. [ABSTRACT FROM AUTHOR]

Research on gas turbine cooling features is extensive, yet studies focused on conventional Reynolds numbers (Re) cannot effectively address the impact of low Re on blade cooling performance, especially relevant for high-altitude unmanned aerial vehicles operating under extremely low Re. In the current study, conjugate heat transfer simulations with Computational Fluid Dynamics (CFD) are used for the cooling performance analysis of an impingement effusion cooling structure with five Re ranging from 2e4 to 4e5, and three blowing ratios as 0.5, 1.0, and 1.5. Initially, a one-dimensional conjugate heat transfer model incorporating four dimensionless parameters is established, analyzing the impact of Re on these parameters. Innovatively, the study explores the mechanism of changes in overall cooling effectiveness through the variation of these dimensionless parameters. Finally, sensitivity analysis with partial derivations is conducted to find each parameter's contribution to the variation in overall cooling performance with Re differences. The CFD simulations of the impingement effusion cooling structure indicate a significant decrease in overall cooling effectiveness with the decrease of Re. The heat transfer ratio and warming factor differed a lot with varied Re. However, the variation in film cooling effectiveness is relatively small due to the mutual influence of coolant coverage and boundary layer distribution characteristics. According to partial derivative values, overall cooling effectiveness is highly sensitive to adiabatic film cooling effectiveness and Biot numbers. However, the heat transfer coefficient ratio and warming factor undergo substantial changes with varied Re , significantly impacting the overall cooling effectiveness. Thus, as Re decreases, the deterioration in internal cooling becomes the primary factor in the decline of overall cooling performance, suggesting targeted efforts to enhance internal cooling performance are recommended. • Overall cooling performance is lower with small Re than that with conventional Re. • Lateral coverage offsets streamwise deficiencies at low Re for adiabatic film cooling. • Heat transfer coefficient ratio is critical role in lower overall cooling performance with low Re. [ABSTRACT FROM AUTHOR]

Recently, considerable attention in the field of cancer therapy has been focused on the mammalian rapamycin target (mTOR), inhibition of which could result in autophagic cell death (ACD). Though novel combination chemotherapy of autophagy inducers with chemotherapeutic agents is extensively investigated, nanomedicine-based combination therapy for ACD remains in infancy. In attempt to actively trigger ACD for synergistic chemotherapy, here we incorporated autophagy inducer rapamycin (RAP) into 7pep-modified PEG-DSPE polymer micelles (7pep-M-RAP) to specifically target and efficiently priming ACD of MCF-7 human breast cancer cells with high expression of transferrin receptor (TfR). Cytotoxic paclitaxel (PTX)-loaded micelle (7pep-M-PTX) was regarded as chemotherapeutic drug model. We discovered that with superior intracellular uptake in vitro and more tumor accumulation of micelles in vivo , 7pep-M-RAP exhibited excellent autophagy induction and synergistic antitumor efficacy with 7pep-M-PTX. Mechanism study further revealed that 7pep-M-RAP and 7pep-M-PTX used in combination provided enhanced efficacy through induction of both apoptosis- and mitochondria-associated autophagic cell death. Together, our findings suggested that the targeted excess autophagy may provide a rational strategy to improve therapeutic outcome of breast cancer, and simultaneous induction of ACD and apoptosis may be a promising anticancer modality. This study demonstrates the improved therapeutic efficacy and its mechanism of transferrin receptor-targeted nanomedicine against breast tumor. Through ligand-receptor mediated active targeting and inducing massive accumulation of autophagic vesicles, combination chemotherapy that acted on both autophagic cell death (ACD) and apoptosis provided enhanced efficacy and reduced toxicity. Image 1 [ABSTRACT FROM AUTHOR]

Deformation-based friction rolling additive manufacturing (FRAM) is a promising solid-state additive manufacturing (AM) approach for producing non-fusible, weldable Al Li alloys. Along with the thermal cycles of conventional AM methods, the materials deposited during FRAM are affected by the repeated force of a tool head. However, the effect of repeated thermal–mechanical cycles on the microstructure and mechanical properties of a deposited material remains unclear. This study attempts to develop mechanisms by characterizing the microstructure and local mechanical properties of FRAM-ed Al Li alloys, with different deposition heights and those that underwent a different number of thermal–mechanical cycles. A recrystallized microstructure is successfully obtained and fine equiaxed grains are observed in the deposited material without pores and cracks. The value of ultimate tensile strength (UTS) reaches 98–91% of the base metal from the top to bottom regions. Under repeated thermal–mechanical cycles (from the top to bottom region), the grain size increases from 2.0 μm to 6.5 μm. The texture strength and diameter of δ' precipitate also increase, while the volume fraction decreases. Together, they lead to a decrease in local UTS and elongation, from 450.7 MPa to 415.1 MPa and from 10.4% to 6.3%, respectively. The relationship between thermal–mechanical cycles and microstructure established in this study provides the foundation for subsequent research on FRAM thermal balance and microstructure regulation. • UTS of the deposited material reached >91% of the Al Li alloy using deformation-based AM technology. • A non-planar connection interface with refine-equiaxed grains (2.0 μm) was formed between two adjacent layers. • The distribution and variation characteristics of microstructure under repeated thermal–mechanical cycles were investigated. • The relationship between the microstructure and mechanical properties was established. [ABSTRACT FROM AUTHOR]

China has a high agricultural output and is a significant carbon emitter; thus, reducing carbon emissions in the agricultural sector is crucial for achieving carbon neutrality. To address this, China implemented the National Agricultural Sustainable Development Experimental Demonstration Zone policy in 2018, in which reducing agricultural carbon emissions (ACE) is a subject of concern. We explore the impact of the policy on agricultural carbon emissions reduction (ACER) using the propensity score matching and differences-in-differences (PSM-DID) methods with a series of robustness tests based on the panel data of prefecture-level cities in China from 2011 to 2020. The results indicate that: (1) the policy significantly reduces carbon emissions and impacts carbon emission sources, with the results passing the robustness tests. (2) According to the mechanism test, agricultural financial support mediates carbon emissions reduction, and the policy reduces these emissions by decreasing the intensity of fiscal support. (3) The heterogeneity analysis illustrates that the carbon emissions reduction effect is more evident in cities with a small urban-rural income gap and a high proportion of agricultural output value. Finally, we provide suggestions to reduce carbon emissions from the perspective of national and local governments. This paper is particularly relevant for achieving sustainable agriculture development. [ABSTRACT FROM AUTHOR]

Fast ionic conductor acting as catalyst offers an efficient choice to produce one-dimensional nanomaterial with high crystallinity and flexible tolerance for lattice mismatch. We report the colloidal synthesis of CuGaS x Se 2 − x nanoribbons with the assistance of Cu 1.75 (SSe) nanocrystals for their intrinsic nature of fast ionic conductors. The structure of the as-prepared CuGaS x Se 2 − x nanoribbons is hexagonal wurtzite with (0 0 1) lattice planes exposed. The composition of nanoribbons can be tuned within the broad range by changing the relative concentration of Se/OA in stock solution. By monitoring the structures, compositions, and morphologies of the nanoribbons, it is confirmed that Cu 1.75 (SSe) nanocrystals are formed firstly, originating from the thermal decomposition of copper diethyldithiocarbamate precursors in the presence of dodecanethiol and selenium–oleylamine, and then act as the catalysts for the growth of the nanoribbons. [ABSTRACT FROM AUTHOR]

A novel method on smoothed-pseudo Wigner-Ville Distribution (SPWVD) to extract single-source zone of the synchronous-networking frequency hopping (FH) signals is proposed in this paper. Since the hop rate and hop period of synchronous-networking FH signals are the same, the method is applied combining with these characteristics. Compare with other methods such as independent component analysis (ICA), the algorithm takes the advantage of the sparse distribution of FH signal in frequency. Then the blind separation algorithm of FH signals with time-frequency ration of matrix (TIFROM) based on short time Fourier transform (STFT) is improved. Simulation results show that the proposed algorithm is effective in the separation of synchronous-networking FH signals, even though the interval between FH signals is relatively small. [ABSTRACT FROM AUTHOR]

In this paper, the outage and bit error rate (BER) performance of a relay networks is studied based on the cascade channel. Firstly, the distribution of the cascade channel, which is the integration of L double-Rayleigh complex random variables (RV), is derived in close form. To overcome the computational difficulty of the arising special function, the probability density function (pdf) of the channel is approximated by the concise Gamma distribution. Through matching the moments of both pdfs, the corresponding shape and scale parameters of the Gamma pdf are obtained. Based on the pdf approximation, the closed-form and accurate expressions of the metrics: outage probability and BER of the cascade channel, are deduced. Numerical results illustrate the accuracy of the proposed performance evaluation. [ABSTRACT FROM AUTHOR]

This paper analyzes the cascade channel estimation of Amplify-and-Forward (AF) multi-relaying systems. To improve the accuracy, a maximum a posteriori (MAP) estimator is obtained with the prior probability distribution function (PDF) of the cascade channel. For lessening the computational amount of the MAP method, the complicated generalized-K distribution is approximated with a Gamma PDF based on the moment-matching method. Moreover, a closed-form and simplified MAP (sMAP) estimator is derived. Numerical simulation shows that the proposed sMAP estimator decreases the computational duration sharply than the MAP method with marginal performance loss, and outperforms its least square (LS) counterpart in the low SNR region. [ABSTRACT FROM AUTHOR]

We hypothesized that neural EGFL like 1 (NELL1) promoter hypermethylation might be associated with the prognosis of gastric cancer. Some studies considered NELL1 as a tumor suppressor gene and our research confirmed for the first time the hypermethylation in the promoter region of NELL1 by the application of mass spectrometry. Promoter hypermethylation can cause the silencing of tumor suppressor genes and promote tumor progression. Based on present studies and research results, we proposed that NELL1 promoter hypermethylation might be associated with cancer staging and the survival of gastric cancer patients and had prognostic value. We hoped that NELL1 promoter hypermethylation would be applied not only for early detection but also prognosis prediction of gastric cancer and would become a new prognostic biomarker. [ABSTRACT FROM AUTHOR]

Abstract: Aim of the study: As a traditional Chinese medicine, seed of Platycladus orientalis(Linnaeus) Franco has been extensively used as a tonic and sedative remedy. The present study was conducted to investigate whether lifespan was extended and the mechanisms of n-butanol extract from seed of Platycladus orientalis (BSPO) in Caenorhabditis elegans. The findings could provide the pharmacological basis for a treatment in traditional medicine. Materials and methods: Lifespan extension by BSPO was evaluated under normal culture conditions and in a stress test. A possible mechanism of the anti-aging effect of BSPO, a change in the stress-resistance of related proteins, was also investigated in C. elegans. Results: It has been shown that BSPO could significantly extend lifespan of C. elegans in a concentration dependent manner under normal culture conditions and stress. Further studies demonstrated that BSPO treatment significantly decreased reactive oxygen species (ROS) accumulation, up-regulated resistance to stress of related proteins, including glutathione S-transferase-4 (GST-4) and heat shock protein-16.2 (HSP-16.2), and reduced the amount of lipofuscin in transgenic C. elegans. Conclusion: These results indicated that BSPO extended the lifespan, which could be attributed to its direct ROS scavenging activity, reducing the amount of lipofuscin and increasing the expression of gens associated with resistance to stress. These obtained data provided valuable support for traditional clinical practice to extend lifespan and to provide tonic remedy. [Copyright &y& Elsevier]

Abstract: A new chiral NOO-tridentate ligand (8R)-2-(2-hydroxyphenyl)-4-methyl-5,6,7,8-tetrahydro-quinolin-8-ol (1) bearing a rigid tetrahydroquinoline framework was prepared and applied in the vanadium-catalyzed asymmetric oxidation of aryl methyl sulfides with H2O2 as oxidant. Less toxic acetone was found to be the proper solvent for the enantioselective oxidation of sulfides. Under the optimal condition, the asymmetric oxidation of aryl methyl sulfides in acetone catalyzed by VO(acac)2/1 at 0°C gives good to high yields (80–95%) of sulfoxides with enantioselectivity up to 77% ee. [Copyright &y& Elsevier]

• Developed a new measurement model for entrepreneurship education effectiveness. • Evidence of measurement model was obtained in an entrepreneurial program. • Entrepreneurial competency, barrier and intention reflect effectiveness differently. • Entrepreneurial barrier mediates the relation between competency and intention. Based on the Methodological Triangulation, this paper proposes and validates a new model for measuring the effectiveness of entrepreneurship education on the three dimensions- entrepreneurial competencies, barriers, and intentions, which are usually studied independently in the literature. A total of 308 entrepreneurship education students, who enrolled in two different campuses at a major Chinese university, participated in this study to explore the feedback mode of three key variables. The findings show that the improvement of participants' entrepreneurial competencies, the reduction of entrepreneurial barriers, and the change of entrepreneurial intention reflect the effectiveness of entrepreneurial education for college students. The proposed model can comprehensively measure the effectiveness of entrepreneurship education by discussing the relations among three key variables and the scope of the model application. The model provides solutions for the development and improvement of entrepreneurship education programs and a standard framework for comparative research on cross-regional or cross-cultural entrepreneurship education. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents new statistical models that predict the number of hurricane- and ice storm-related electric power outages likely to occur in each 3km×3km grid cell in a region. The models are based on a large database of recent outages experienced by three major East Coast power companies in six hurricanes and eight ice storms. A spatial generalized linear mixed modeling (GLMM) approach was used in which spatial correlation is incorporated through random effects. Models were fitted using a composite likelihood approach and the covariance matrix was estimated empirically. A simulation study was conducted to test the model estimation procedure, and model training, validation, and testing were done to select the best models and assess their predictive power. The final hurricane model includes number of protective devices, maximum gust wind speed, hurricane indicator, and company indicator covariates. The final ice storm model includes number of protective devices, ice thickness, and ice storm indicator covariates. The models should be useful for power companies as they plan for future storms. The statistical modeling approach offers a new way to assess the reliability of electric power and other infrastructure systems in extreme events. [Copyright &y& Elsevier]

Hydrogen leakage diagnosis has attracted more and more attention, especially in the high-pressure hydrogen system of fuel cell vehicles, where the chance of deflagration is quite high. Traditional methods for detecting gas leaks rely on stationary sensor measurements and manual inspections. Manual inspections are time and resource-consuming, and it is challenging to achieve real-time, comprehensive inspections in large spaces. In this study, a new Adaptive Stream Stripe-Background Oriented Schlieren (ASS-BOS) method for hydrogen jet visualization is proposed. Three different background patterns, namely random scatter background, checkerboard background, and stripe background, are designed for multiple experiments. The results show that when observing hydrogen jets in the far-field region (low-density gradient), ASS-BOS has higher accuracy and resolution, detects larger background displacements, and shows more turbulence details. In addition, the concentration distribution of the hydrogen jet is reconstructed using ASS-BOS. We compare the concentration of the hydrogen jet obtained from the inversion of the ASS-BOS method with the experimental results measured by the sensor. We find that the average error is 3.45%, indicating that ASS-BOS can accurately reconstruct the concentration distribution of the hydrogen jet. • A new ASS-BOS method is proposed to reconstruct the radial concentration distribution of hydrogen jets. • A series of background pattern was designed based on the characteristics of hydrogen jets. • The visualization of the hydrogen jet was tested comprehensively using different background images. • The ASS-BOS method has better resolution and accuracy for large-area hydrogen jet observation. [ABSTRACT FROM AUTHOR]

• The DMSP-OLS SNL data and NPP-VIIRS composite data were integrated. • The estimated CO 2 emissions model using nighttime light datasets was structured. • The spatiotemporal dynamics of CO 2 emissions were analyzed. • CO 2 emissions from provincial to county scale were analyzed. • Policy implications for CO 2 emissions reduction were suggested. CO 2 emissions caused by socioeconomic development and energy consumption in China have put enormous pressure on emissions reduction for Chinese government. In response to CO 2 emissions reduction in China, this study integrated the Defense Meteorological Satellite Program's Operational Linescan System (DMSP-OLS) stable nighttime light (SNL) data and Suomi National Polar-orbiting Partnership (NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) composite data, and established the integrated nighttime light datasets from 1992 to 2016. The estimated CO 2 emissions model utilizing the integrated nighttime light datasets and statistical CO 2 emissions at the provincial level from 1995 to 2016 were established. Finally, spatiotemporal dynamics of CO 2 emissions were simulated from multiscale. The results clearly showed that: (1) The fitting results of regression relationship between DMSP-OLS SNL data and NPP-VIIRS composite data met the accuracy requirements. The CO 2 emissions estimated model was valid. (2) The total amount of energy consumption CO 2 emissions in China had increased from 1889.3340 Mt in 1995 to 4683.3165 Mt in 2016, with a total growth of 2.47 times. (3) The high CO 2 emissions regions were clearly agglomerated in eastern coastal China from the pixel scale, the highest CO 2 emissions provinces were concentrated in Hebei and Shandong, the high CO 2 emissions prefecture cities were concentrated in Around Bohai Gulf area, eastern coastal China and some developed cities, and the high CO 2 emissions counties were concentrated in eastern coastal China and western energy intensive counties. (4) The relatively-slow growth accounted for the highest proportion among the five growth types, and the CO 2 emissions rapid growth regions were concentrated in eastern China at provincial, prefectural and county scale. The western regions accounted for the largest area proportion in five growth types at prefectural scale. We provided policy implications based on the results, which was beneficial to propose mitigation CO 2 emissions reduction in China. [ABSTRACT FROM AUTHOR]

In order to evaluate the role of external Si addition in the intermetallic formation of 8009 aluminum alloy, the mixed powders of AlSi20 alloy and rapidly solidified 8009 aluminum alloy were extruded and annealed under various annealing conditions. The employed characterization techniques included scanning electron microscope, energy dispersive spectroscopy, X-ray diffraction and transmission electron microscope. The results showed that the formation of Al 4.5 FeSi phase was enhanced while the contents of Al 12 (Fe, V) 3 Si dispersion in 8009 aluminum alloy matrix and Si phase were decreased in the annealed AlSi20/8009 aluminum alloy with increasing annealing temperature (480 °C–540 °C) and annealing time (15 min–60 min at 540 °C). A novel nano-sized phase containing 5.58–6.98Al, 64.14–66.89Si, 25.59–26.20V and 1.91–2.65Fe (at. %) was observed at annealing temperature of 540 °C, which occupied a slice stacking morphology and had many sharp edges and corners. By comparing with the annealed 8009 aluminum alloys, the external Si addition was found to be responsible for the formation of Al 4.5 FeSi and the nano-sized phases in the annealed AlSi20/8009 aluminum alloys. The intermetallic formation mechanism and the role of external Si addition were also discussed based on experimental observations. • The mixed powders of AlSi20 and 8009Al were extruded and annealed. • The effects of annealing temperature and time were investigated. • A novel nano-sized phase was observed at annealing temperature of 540 °C. • The mechanism of intermetallic formation were discussed. [ABSTRACT FROM AUTHOR]

Schedule maintenance activities for hydrogen fuel cell vehicles are aimed to keep them in better condition in long-term operation. In this paper, we develop a reinforcement learning based schedule maintenance strategy, which is used to comprehensively consider the balance between safety and maintenance cost, so as to find the optimal maintenance strategy. A multi-level framework is established with remaining useful life of key components, fault tree analysis, and logistics cost model to generate an exploration environment that can express the operational stability, the failure rate of components, and the cost of repair and storage. The trained agent combines a deep neural network to explore the optimal strategy under the dynamic reliability of key components. Finite steps are the constraints. Safety rates, maintenance cost, and episode of operation are incorporated into a multi-objective reward function. The hydrogen supply circuit of fuel cell vehicle is simulated via Python. The trained agent is compared with traditional time-based schedule maintenance strategy and corrective maintenance strategy. The results show that the reinforcement learning based schedule maintenance agent has optimized the total reward, cost control and accident rate by 77%, 59% and 5%, respectively, compared with the traditional time-based schedule maintenance strategy. In the safe operation management of fuel cell vehicles, efficient and stable decision-making ability has been achieved. • An adaptive maintenance strategy of deep reinforcement learning is proposed. • An exploration environment of FCV is established. • The deep Q network is proposed to solve the maintenance problem. • The efficient and stable decision-making ability is much better than time-based scheduled maintenance strategy. [ABSTRACT FROM AUTHOR]

The main objective of this work is to propose a new hydrogen leakage visualization method to evaluate hydrogen jet pressure. A mathematical model is proposed to reveal the intensity distribution of the laser beam through the hydrogen jet at different outlet pressures. Our findings show that the hydrogen jet can be regarded as a gas lens with adjustable laser beam energy, and a change in jet pressure causes a change in the half-height width of the spectrum, which affects the intensity distribution of the laser beam after it passes through the hydrogen jet. The error between the light intensity distribution of the theory and the light intensity distribution obtained from the experimental results is 2.59%. The error is within the allowable range. Our technique shows that the variation of the hydrogen jet pressure can be estimated by analyzing the intensity data after the laser passes through the hydrogen jet. • The variation in hydrogen jet pressure can be determined by evaluating the laser beam intensity data. • The mechanism of the hydrogen jet considered to be a gas lens with adjustable laser beam energy has been disclosed. • A two-parameter Gaussian model with the intensity distribution of the laser beam and jet pressure is proposed. • The FWHM increases linearly with increasing hydrogen jet pressure. [ABSTRACT FROM AUTHOR]

In this paper, a modified model is proposed for an oscillating foil energy harvesting device, and the corresponding mathematical model is established too. A grid model for foil NACA0015 is built by using dynamic and moving mesh technology of the Computational Fluid Dynamics (CFD) software FLUENT. To understand the hydrodynamic performance and energy extraction capability of the modified model, the effects of motion parameters (heaving component parameters and pitching component parameters) are investigated. The evolutions of angle of attack and vortex field are examined. The results show that motion radius and heaving amplitude play important roles in impacting the time-averaged power coefficient. As the frequency increases, the peak value of the effective angle of attack is decline. The effect of pitching amplitude is gradually increased on the time-averaged power coefficient. Under the large frequency, the energy extraction efficiency is more sensitive to the motion radius and heaving amplitude. Moreover, there exists an optimal oscillation frequency to achieve a maximum time-averaged power coefficient for each pitching amplitude. [ABSTRACT FROM AUTHOR]

The impacts of soil organic matter (SOM), aging and sterilization on the production of lignin peroxidase (LiP) and manganese peroxidase (MnP) by Phanerochaete chrysosporium during the biodegradation of pyrene in soils were investigated. The biodegradation of pyrene by P. chrysosporium decreased with increasing SOM content, whereas the maximum activities of LiP and MnP increased, which indicates that SOM outweighed pyrene in controlling enzyme production. Sterilization enhanced the degradation of pyrene due to the elimination of competition from indigenous microbes, whereas aging led to a reduction in the degradation of pyrene primarily through changes in its sorbed forms. Both sterilization and aging could reduce SOM content and alter its structure, which also influenced the bioavailability of pyrene and the enzyme activity. The sterilization and aging processes caused changes in the degradation of pyrene, and the enzyme activities were greater in soils with high SOM contents. MnP was related to the degradation of pyrene to a greater extent, whereas LiP was more related to the decomposition of SOM. [ABSTRACT FROM AUTHOR]