An efficient regioselective synthesis of 2‐acylpyrroles via palladium‐catalyzed addition of pyrroles with benzonitriles and subsequent hydrolysis is developed. The direct acylation reaction of protected as well as (NH)‐free pyrroles proceeded smoothly to afford 2‐acylpyrrole scaffolds of high biological interest.
Creep behavior of Al-Si hypereutectic alloys inoculated with phosphorus was investigated using the impression creep testing. The results showed that at stress regimes of up to 400-450 MPa and temperatures up to 300 °C, no significant creep deformation occurred in both uninoculated and inoculated specimens; however, at temperatures above 300 °C, the inoculated alloys presented better creep properties. Creep data were used to calculate the stress exponent of steady-state creep rate, n, and creep activation energy, Q, for different additive conditions where n was found varied between 5 and 8. Owing to the fact that most alloys have lower values for n (4, 5), threshold stress was estimated for studied conditions. The creep governing mechanisms for different conditions are discussed here, with a particular attention to the effect of phosphorous addition on the microstructural features, including number of primary silicon particles, mean primary silicon spacing, and morphology and distribution of eutectic silicon. 相似文献
Because of computational complexity, the deep neural network (DNN) in embedded devices is usually trained on high-performance computers or graphic processing units (GPUs), and only the inference phase is implemented in embedded devices. Data processed by embedded devices, such as smartphones and wearables, are usually personalized, so the DNN model trained on public data sets may have poor accuracy when inferring the personalized data. As a result, retraining DNN with personalized data collected locally in embedded devices is necessary. Nevertheless, retraining needs labeled data sets, while the data collected locally are unlabeled, then how to retrain DNN with unlabeled data is a problem to be solved. This paper proves the necessity of retraining DNN model with personalized data collected in embedded devices after trained with public data sets. It also proposes a label generation method by which a fake label is generated for each unlabeled training case according to users’ feedback, thus retraining can be performed with unlabeled data collected in embedded devices. The experimental results show that our fake label generation method has both good training effects and wide applicability. The advanced neural networks can be trained with unlabeled data from embedded devices and the individualized accuracy of the DNN model can be gradually improved along with personal using. 相似文献
ABSTRACTHierarchical SAPO-34 molecular sieve was synthesized hydrothermally in the presence of different concentrations of n-propylamine (NPA) as the mesoporous generating agent. It has been found that the mesoporous structure and morphology of the hierarchical SAPO-34 was depended to the amount of NPA used. The catalytic activity of the synthesized materials for methanol to propylene conversion were evaluated. A high selectivity for propylene (44.5%) compared to a conventional microporous SAPO-34 (28.7%) was observed with propylene to ethylene (P/E) ratio (3.6) which was attributed to the less total acidic sites measured by NH3-TPD and the optimal combination of mesoporous and microporous reaction paths. The synthesized hierarchical SAPO-34 catalysts were characterized by XRD, FE-SEM, BET, NH3-TPD and TGA techniques. 相似文献
The influence of drying air temperatures, drying air flow rate and feed flow rate on percentage survival rate (% SR) of starter and probiotic bacteria, moisture content, water activity and colour of probiotic yoghurt powder produced using a pilot‐scale spray dryer was investigated. Optimisation of spray drying conditions was achieved based on the desirability value. Results showed that inlet air temperature, drying air flow rate, feed flow rate and outlet air temperature of 150 °C, 478 m3/h, 2 L/h and 63.3 °C, respectively, were optimal conditions to produce powder that meets quality specifications and with a satisfactory% SR. 相似文献
Wireless Personal Communications - Searchable encryption schemes allow documents’ owners to store their encrypted documents on servers, search for the desired keyword and then download only... 相似文献
Sodium cocoyl sarcosinate is an important surfactant with a particular chemical structure and many practical applications in various industries. The synthesis of sodium cocoyl sarcosinate involves the reaction of cocoyl chloride and N-methyl glycine. The influences of reactant molar ratios, temperature, reaction time, pH, and solvent on the reaction yield were investigated and also the kinetics of the reaction was studied. It was found that the reaction follows second order kinetics and the reaction rate constant is 0.0153?mol?1?L?s?1 at 35?°C. Also production of sodium cocoyl sarcosinate was carried out at bench and pilot scales which is described in details. 相似文献
The applicability of erbium–metal–organic framework (Er-MOF) in the adsorption and removal of methylene blue from aqueous solution has been studied. Er-MOF was synthesized by hydrothermal method and characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray powder diffraction. The high thermal stability, water stability and accessible nano-sized aperture for the Er-MOF could endow it with a very high potential in adsorption of dye pollutant. The adsorption isotherm, kinetic and thermodynamic investigations confirm that the adsorption behavior is based on Langmuir isotherm with an exothermic mechanism and enthalpy-driven process. The speed adsorption process (30 min), low cost, high efficiency, big surface area, selectivity and very high and rapid reusability are the main advantages of the proposed compound as a sorbent. 相似文献
The Hermite spectral approximation of a hyperbolic Fokker–Planck (FP) optimality system arising in the control of an unbounded piecewise-deterministic process (PDP) is discussed. To control the probability density function (PDF) corresponding to the PDP process, an optimal control based on an FP strategy is considered. The resulting optimality system consists of a hyperbolic system with opposite-time orientation and an integral optimality condition equation. A Hermite spectral discretisation is investigated to approximate solutions to the optimality system in unbounded domains. It is proven that the proposed scheme satisfies the conservativity requirement of the PDFs. The spectral convergence rate of the discretisation scheme is proved and validated by numerical experiments. 相似文献