Search

This paper proposes a kind of improved variable integral PID control algorithm. Simulation results show that the variable integral PID control algorithm improves the system quality compared with the normal PID algorithm. It overcomes the problems of overshoot and integral saturation in the normal PID algorithm. With the seldom parameters, we are easy to set it.

The comparative study of numerical results on pulverized coal combustion process with CFD has become an important measure for direct engineering practice. In this paper, a combustion facility was simulated numerically with the Fluent code to investigate the process of coal combustion. Firstly, geometric models, grid and boundary type were established in the Gambit. Secondly, required models, physical properties and working conditions were chosen in the solver. Then, the important diagrams of each component displayed distinctly in the post professor. The simulation results showed that the rules of the volatile releasing and combustion processes of coke could provide important references to improve the combustion of the pulverized coal.

The equilibria phase of the ternary systems NaCl-CsCl-H2O was studied at 50°C by the isothermal evaporation method. The equilibrium phase diagrams were plotted in line with the experimental data. It suggest that the phase diagram of NaCl-CsCl-H2O is the simple eutectic type where one invariant point is found to have the compositions of 12.3% NaCl, 54.1% CsCl and 33.6% H2O by mass, respectively. The study provide fundamental thermodynamic data of brine system that contains sodium and cesium, and has practical significance for the brine’s comprehensive utilization.

large amount of granite powders wastages were produced during the process of the stone processing, therefore the research on recycling and utilizing the wastages was carried out. Based on the size distribution of granite powders specified by the laser particle size analyzer, the research on the influence of granite stone powder on the mechanical properties of cement mortar was carried out through the cement grinding test and scanning electron microscopy (SEM). The test result shows as follows. The flexural and compressive strength of cement mortar with replacement rate of granite stone powders of 20% is the highest when the same particle size of granite stone powder is incorporated. When the replacement rate of granite powders is the same, the smaller the particle size of granite stone powder is, the higher the flexural and compressive strength of cement mortar is. When the replacement rate of granite powders is 20%, with the particle size ranging from 0μm to 45μm, the filling effect of the granite stone powder can be fully utilized to the best.

A novel complex was obtained by self-assembly of the corresponding alkaline earth metal chlorate with a ligand, Azobisisobutyronitrile in this paper. The coordination principle of the as-prepared complex was analyzed firstly, and then its structure and thermal behavior were detected by the infrared spectrogram and TG-DTA

Myofibrillar protein gel properties were studied. Based on which Box-Benhnken center-united experiment was designed for optimization of ratio scheme for gelation strength. The optimum conditions for best gel strength were found to the transgluninase 0.37% of myofibrillar proteins, GDL 1.19%, in 0.88mol/L NaCl concentration at pH 5.96 to form 40mg/ml protein concentration solution. The gel strength was 316.953g. The study showed that transgluninase and GDL could interact significantly in improving gel strength (P

An efficient agar plate mutagenesis and screening technique for improving mutation frequency was established by using dielectric barrier discharge (DBD) plasma. And very few studies have reported strains of A. calcoaceticus as phosphate solubilizing plant-associated bacteria. In this study, A.calcoaceticus showed a good ability in phosphate solubilizing. DBD plasma was conducted to A. calcoaceticus mutation for improving the phosphate-soubilizing activity. The results showed that the phosphate-soubilizing activity of mutants increased compared with original strain, and the phosphate-soubilizing activity of the best mutants up to 584.3mg/L, is 1.23-fold of original strain. It demonstrated that DBD plasma treatment has a high-efficient quality, and it will be a useful method of mutation.

The paper introduces the work process and control requirements of precast concrete pipe pile perfusion. Th design is based on the S7-200PLC and AE80THTD touch screen control system. It elaborates the hardware components of control system, I / O configuration, software workflow and control chart. The practical operation shows that the control system is convenient to manufacture, install and commission, easy to operate, and it is stable and reliable.

The Li3V2(PO4)3/C cathode material is prepared by fast microwave synthesis route using PEG as carbon source. The samples were characterized by X-ray diffraction (XRD), galvanostatically charge/discharge test and electrochemical impedance spectroscopy (EIS). XRD result shows that the material was well crystallized and the structure was indexed as a monoclinic Li3V2(PO4)3/C. The electrochemical tests of material exhibit good cycling performance, which delivered a high initial discharge of 125.2 mAh g-1 at 0.2C and the retention of capacity was 92.4% after 50 cycles. From this study, the PEG-based microwave preparation method is regarded as a feasible route for the preparation of Li3V2(PO4)3/C cathode material.

Hilbert-Huang transform (HHT) is a new time-frequency-domain analysis method, which is suitable for non-stationary and nonlinear signals. In this paper, endpoint continuation and ensemble empirical mode decomposition (EEMD) decomposition method are introduced to improve the HHT, which solve the endpoint winger and modal aliasing problem. The improved HHT (IHHT) is used for analyzing the harmonic signal and detecting the fault signal of power system. Simulation results show that IHHT is feasible and effective for harmonic analysis and fault detection.

The orthotropic bi-material plane interface end of a flat lap is studied by constructing new stress functions and using the composite complex function method of material fracture. When the characteristic equations’ discriminates and, the theoretical formulas of stress fields, displacement fields and the stress intensity factor around the flat lap interface end are derived, indicating that there is no oscillatory singularity. There are multiple stress singularities of the orthotropic bi-material plane flat lap interface end.

Supercritical fluid extraction (SFE) of lycopene from freeze-dried tomato pomace(peels and seeds) with CO2 was explored. The effect of different technical parameters, such as temperature (40°C, 50°C, 60°C), pressure (35MPa, 40MPa, 45MPa) and particle size (three degree index), on the extraction yield and the content of lycopene in extracts was determined with statistical analysis.The product obtained by supercritical CO2 extraction at over 35MPa contained the highest concentration of lycopene, while the product rich in β-carotene and lutein was obtained at below 30MPa.The product obtained by supercritical CO2 extraction at 40MPa and 60°C contains the highest concentration lycopene of 32.52±1.02g/100g dry material.

Companies are increasingly focusing on customer participation to create value for the firms and their customers. To date, evidence regarding the effects of customer participation as a marketing tool has been primarily anecdotal. Relying on customer behavior theory and marketing theory, we develop a framework that explores the effects of customer participation on service quality, customer satisfaction and customer value. On the basis of which, an SEM analysis was conducted on the personal development industry. The results show that information exchange, cooperative behaviors and personal interaction have positive effects on service quality, customer satisfaction and customer value. Based on the results, this study explains the practical and academic implications for companies promoting customer creative participation.

Silicon nitride nanowires have been synthesized by mechanosynthesis method. The silicon powders were first milled for 160 hours under the presence of ammonia gas with 300kPa. And then they were heat-treated at 1250 for 2 hours in the pure nitrogen gas. The phase and the microstructure of the as-prepared product were detected by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The results showed that the product consisted of α-Si3N4 nanowires. The nanowires had the length of tens of millimeters and the diameters of 50～100nm. The vapor-solid (VS) mechanism was employed to interpret the nanowires growth.

A special grinding device is designed to solve the problems of the shape precision, surface quality and grinding efficiency. The device is based on the sine generator and triaxial speed to achieve the ideal Grinding trajectory. The accuracy of grinding in spherical valve core & surface quality is assured and improved by three-dimensional elastic support, pressurized floating contact and auto centering device in core and lapping tools. The grinding efficiency is highly enhanced by using the lateral and vertical speeding workpiece installration and the automatic control. The device is worth widely being applied to achieve a good large diameter hemispherical workpiece grinding.

The composite antibacterial agents were prepared with Medical stone containing Cu2+ and Zn2+ by liquid ion-exchange reaction. The ion exchange capacity of the as-prepared Medical stone composite antibacterial agents (MSAA) products were investigated by ICP-AES, and the antibacterial activities of the agents were tested by Bacteriastasis ratio, and the structures were characterized by XRD and SEM. The results show that the conditions of preparation, such as pH, concentrations of copper and zinc ions, reaction time and reaction temperature, have important influences on the ion exchange of MSAA. The maximum ion exchange capacity have been obtained when 0.2mol/l Cu2+ and 0.6 mol /l Zn2+ reacted with Medical stone powers in the solution with pH values of 8 for 8 hours at 50 °C. Meanwhile good antibacterial activities and safety are also gained. The reasons for causing the above results are that copper and zinc ions can enter the framework of Medical stone through ion exchanging and adsorption, and are released slowly owing to its porosity.

Using silicon powders as raw materials, adding nano-silicon nitride as a diluent and NH4Cl3 and FeCl3 as catalysts, α-phase silicon nitride powders were prepared by direct nitridation method. The silicon powders were first milled with 20% α-Si3N4 and 4% NH4Cl3 for 30 minutes. Then the mixture was heat-treated at 1300°C for 1 hour in the pure nitrogen gas. The phases and their content of the as-prepared product were detected by X-ray diffraction (XRD) and the microstructure was studied by scanning electron microscope (SEM). The results showed that the product mainly consisted ofα-Si3N4 with a mass fraction over 92% and were submicron-sized particles．

Silicon nitride powders high in β-phase content have been prepared by direct nitriding method. The silicon powders were first milled with 30%α-Si3N4 and 4% FeCl3 for 30 minutes. Then the mixture was heat-treated at 1400°C for 2 hours in the pure nitrogen gas. The phase and the microstructure of the as-prepared product were detected by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results showed that the product mainly consisted of β-Si3N4, whose content is more than 92%, and a little amount of α-Si3N4, and no silicon were detected within the detection limit.

Supercritical carbon dioxide extraction had been used in the extraction conditions for carotenoids from the marigold flower (Tagetes erecta L.). Five significant factors (particle size, temperature, pressure, time and co-solvent addition) on total carotenoid yield were obtained using one-at-a-time design (p≤0.05). The optimal extraction conditions were 55 oC, 50 MPa and 180 min. Under these conditions, the yield of carotenoids was 6.872mg/g.

The influence of Silica fume/Nanosilica on the Performance of phosphoaluminate cement was studied in the paper. The microstructure and morphology was determined by X-ray diffraction and scanning electron microscopy. The experimental results show that the phosphoaluminate cement with 4% of added Silica fume/Nanosilica(1:1) by weight of cement has an optimum splitting strength, in which the increase of splitting strength are about 15.1%,11.8% and 24.6% at 3days,7days and 28 days. The reason for causing the above results are the hydration rate and the amount of the hydrates of PALC with 4% Silica fume/Nanosilica have been increased significantly at different hydration time because of the role played by Silica fume and Nanosilica together.