Concentrating a trace amount of molecules from liquids, solid objects, or the gas phase and delivering them to a localized area are crucial for almost any trace analyte detection device. Analytes ...within a liquid droplet resting on micro/nanostructured surfaces with liquid-repellent coatings can be concentrated during solvent evaporation. However, these coatings suffer from complex manufacturing procedures, poor versatility, and limited analyte enrichment efficiency. Here, we report on the use of an acoustic levitation platform to losslessly concentrate the analyte molecules dissolved in any volatile liquid, attached to solid objects, or spread in air. Gold nanoparticles can be simultaneously concentrated with the analytes in different phases, realizing sensitive, surface-enhanced Raman scattering detection even at attomolar (10
mol/L) concentration levels. The acoustic levitation platform-enabled, lossless analyte enrichment can significantly increase the analytical performance of many conventional microsensing techniques.
An approach for optimizing the rotor shape of a variable reluctance (VR) resolver is presented. In the optimization, the shape of the rotor is described with Fourier series. The Taguchi optimization ...method, combined with a finite-element method (FEM), is used to calculate the value of the objective function of the VR resolver and make the error of the angular position of the VR resolver to be minimum. The VR resolver with three-pole pairs is used as an example to show the effectiveness of the optimization approach.
Due to its unique and attractive characteristics, the induction motor (IM) has been widely used for years. How to design an IM with desired characteristics and how to realise high performance control ...for a given IM, these have always been hot research topics to many researchers. No matter what control technology is used to achieve high‐performance drive of IM, it depends on in‐depth understanding of motor parametric characteristics and their accurate acquisition. An effective determination method is proposed to improve the parameter accuracies of the equivalent circuit for induction motors by combining non‐rotor test with dual‐load test and using this method to measure and analyse the parametric characteristics of IM. Experimental validations are carried out on two induction motors with open‐slot rotor and closed‐slot rotor, respectively. Compared with the traditional methods, the proposed method has higher accuracy and can be an effective tool for design, control, and testing research of IM.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
In its applications, the starting performance of a 3‐phase induction motor (IM) is very important. The starting torque of the motor should be as high as possible within the safe current range of the ...motor driver. In the study, the optimal frequency for motor starting is derived from the frequency characteristic of the IM. Through the analysis of the characteristics, the optimal frequency point can be found, which is able to generate the maximum torque per unit drive current. Both theoretical analysis and experiments show that the IM with the optimal starting frequency can generate the maximum torque for a given current. The traditional methods, such as soft‐start, can reduce the starting current, but at the expense of lowering starting torque. This starting technology can solve the problem caused by traditional methods, improve the starting performance of the motor system significantly, and lower the requirement for the current redundancy of the motor driver effectively.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Curcumin loaded solid lipid nanoparticles.
•Curcumin loaded solid lipid nanoparticles (C-SLNs) with sustained drug release enhanced the aqueous dispersibility and chemical stability of the ...drug.•Blending a suitable amount of liquid lipid Sefsol-218® into solid lipids reduced the particle size and improved the physical stability of the C-SLNs.•Both qualitative and quantitative fluorescence techniques were conducted to investigate the cellular uptake of the drug in an unformulated solution and in the C-SLNs.•C-SLNs exhibited prolonged growth inhibition and cellular uptake in cancer cells.
The aim of the present study was to blend liquid lipids with solid lipids to encapsulate curcumin in solid lipid nanoparticles (SLNs), thereby improving the dispersibility and chemical stability of curcumin, prolonging its antitumour activity and cellular uptake and enhancing its bioavailability.
Curcumin-loaded SLNs (C-SLNs) were prepared by high-pressure homogenisation with liquid lipid Sefsol-218®. The morphology, stability and release of curcumin in the optimised formulation were investigated. The anti-cancer activity of the formulation was evaluated in MCF-7 cells. Fluorescence spectrophotometry was used to quantify cellular uptake of the drug. The pharmacokinetic profiles of curcumin in SLNs after intravenous administration were studied in rats.
Blending Sefsol-218® into a lipid matrix reduced the particle size without improving drug loading. An optimised formulation consisting of Dynasan 114®, Sefsol-218®, and Pluronic F68® (630:70:300, w/w) loaded with 0.8% drug was prepared. This formulation could be dispersed in water with a mean particle size of 152.8±4.7nm and a 90% entrapment efficiency. Curcumin displayed a two-phase sustained release profile from C-SLNs with improved chemical stability. Compared to the solubilised solution, C-SLNs exhibited prolonged inhibitory activity in cancer cells, as well as time-dependent increases in intracellular uptake. After intravenous administration to rats, the bioavailability of curcumin was increased by 1.25-fold.
C-SLNs with improved dispersibility and chemical stability in an aqueous system have been successfully developed. C-SLNs may represent a potentially useful cancer therapeutic curcumin delivery system.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK
Accuracy of the motor parameters is important in realizing high performance control of permanent magnet synchronous motor (PMSM). However, the inductance and resistance of motor winding vary with the ...change of temperature, rotor position and current frequency. In this paper, a technology based on circuit model is introduced for realizing online identification of the parameter of PMSM. In the proposed method, a set of nonlinear equations containing the parameters to be identified is established. Considering that it is very difficult to obtain the analytical solution of a nonlinear system of equations, Newton iterative method is used for solving the equations. Both the simulation and testing results confirm the effectiveness of the method presented.
Most solid-state imine-linked covalent organic frameworks (COFs) are non-fluorescent due to aggregation-caused quenching because of strong π-π interactions and rotationally unstable imine bonds in ...the stacked layers of COFs. Here, we report a green-emitting fluorescent imine-based COF (ODA-TP-COF) by integrating flexible building blocks and transforming the COF into nanoscale sheets. Due to the existence of flexible non-planar units, the interlayer distance of ODA-TP-COF increases, which weakens the π-π interaction and thus reduces the aggregation-caused fluorescence quenching. Our further study found that the ODA-TP-COF dispersed in different solvents has different fluorescence properties, and surprisingly when methanol was used as the solvent for ODA-TP-COF, the presence of a small biological molecule, folic acid, could significantly and selectively induce a blue-shifts of ODA-TP-COF fluorescence peak. It is the first time that the ODA-TP-COF could serve as a highly selective fluorescent probe for the visual detection of folic acid.
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•Prepared a green-emitting fluorescent imine-based COF by integrating flexible building blocks.•Folic acid could significantly and selectively induce the blue-shift of the fluorescence peak of COF.•It is the first time that the COF was served as a fluorescent probe for the visual detection of folic acid.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
The demand for the high-performance and low-cost position control actuators in many applications promotes the development of three-phase hybrid stepper motors. The torque ripple, loss, and pullout ...torque of the motor are the key factors to be considered in the motor application. In order to solve the problems of the open-loop control mode, this paper proposes a new “sensorless closed-loop” control mode to significantly improve the performance of three-phase hybrid stepper motors. This control mode is developed by estimating the rotor position with the Extended Kalman filter observer, thereby realizing the closed-loop control of the motor with sensorless technology. This paper illustrates the effects of this control mode by analyzing motor noise, losses, and pullout-torque. The results show that the use of the “sensorless closed-loop” control mode presented can effectively improve the performance of the stepper motor while maintaining the advantages of the motor in terms of cost and size. These results have positive significance for the development, application, and promotion of high-performance three-phase hybrid stepper motor systems.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Agroforestry has been widely practiced in the Loess Plateau region of China because of its prominent effects in reducing soil and water losses, improving land-use efficiency and increasing economic ...returns. However, the agroforestry practices may lead to competition between crops and trees for underground soil moisture and nutrients, and the trees on the canopy layer may also lead to shortage of light for crops. In order to minimize interspecific competition and maximize the benefits of tree-based intercropping systems, we studied photosynthesis, growth and yield of soybean (Glycine max L. Merr.) and peanut (Arachis hypogaea L.) by measuring photosynthetically active radiation, net photosynthetic rate, soil moisture and soil nutrients in a plantation of apple (Malus pumila M.) at a spacing of 4 m × 5 m on the Loess Plateau of China. The results showed that for both intercropping systems in the study region, soil moisture was the primary factor affecting the crop yields followed by light. Deficiency of the soil nutrients also had a significant impact on crop yields. Compared with soybean, peanut was more suitable for intercropping with apple trees to obtain economic benefits in the region. We concluded that apple-soybean and apple-peanut intercropping systems can be practical and beneficial in the region. However, the distance between crops and tree rows should be adjusted to minimize interspecies competition. Agronomic measures such as regular canopy pruning, root barriers, additional irrigation and fertilization also should be applied in the intercropping systems.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
For the optimization of three-phase hybrid stepper motors with complex electromagnetic structures, an optimization method is presented in this paper. The method is a combination of 3D-FEM and the ...Taguchi optimization method intended to reduce the dependence on FEM results during the optimization calculation. In this paper, the optimization method is used in the optimization of the tooth shape of the three-phase hybrid stepper motor, and the objective is to reduce the noise caused by harmonics in the "torque-angle characteristic" of the motor. It is clear that traditional optimization methods make it very difficult to carry out such an optimization calculation as a large number of finite element calculations have to be used in the optimization process, and the required computation time is extremely long. Using the optimization method presented in the paper, the optimization becomes feasible because the number of finite element calculations is greatly reduced and the computation time is thus greatly reduced. In order to check the effectiveness of the optimization, the waterfall diagram for noise analysis and its application to check torque ripple are also presented in the paper. Both simulation and test results show that the optimized structure can significantly reduce the motor noise caused by torque ripple. Therefore, the optimization method proposed in this paper can be an effective tool for the optimal design of high-performance motors, including stepper motors.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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