Abstract. The dynamic load-sharing characteristics of aircraft face gear dual-power split transmission system (FGDPSTS) are taken as the research object. Considering the factors of time-varying meshing stiffness, comprehensive error, backlash, support clearance, spline clearance, torsional stiffness, and support stiffness, the dynamic load-sharing model was constructed based on the lumped-parameter method. The loaded tooth contact analysis (LTCA) simulation method was used to calculate the time-varying meshing stiffness. The dynamic load-sharing coefficient (DLSC) is obtained by using Runge–Kutta method. The influences of errors, backlash, support clearance, spline clearance, torsional stiffness and support stiffness on DLSC were analyzed, and the biggest factors affecting dynamic load-sharing performance were found out. The results show that the influence of the backlash of the two-stage herringbone gear pair on the DLSC is more sensitive. The influence of support clearance on the DLSC is less. The load-sharing coefficient increases with the increase of the installation error and eccentricity error, and the influence of the error of the two-stage gears on the system load-sharing performance is the most sensitive. The torsional stiffness has little effect on the load-sharing coefficient of one stage but has great effect on the two-stage load-sharing coefficient. The influence of support stiffness on the DLSC of two-stage is stronger. It provided a theoretical basis for the dynamic stability optimization design of the system.
In this study, the intercalated hydrotalcite (HT)/epoxy (EP) nanocomposites containing red phosphorous (RP) (HT-RP/EP) were prepared by in-situ polymerization. Firstly, low-molecular-weight polyamide 6 (PA6)/HT nanocomposite was prepared in the presence of organ-hydrotalcite with alanine as an initiator at 150°C. And then, PA6/HT composite and a certain amount of RP incorporated into epoxy resin in the presence of curing agent (polyamide 650) and HT-RP/EP nanocomposite was prepared successfully. Finally, the micro-structure and flame resistance were characterized by scan electron microscope (SEM) and vertical burning method, respectively. The results showed that HT was dispersed in the epoxy matrix evenly. HT-RP/EP nanocomposites showed significant flame resistance. When the content of both of HT and RP was 5%, the flame resistance achieved FV-0 level.
Hydrophilic poly((poly(ethylene glycol) methyl ether methacrylate) (P(PEGMA)) brushes were grafted from chloromethylated polyethersulfone (CMPES) hollow fiber membrane surface by surface-initiated atom transfer radical polymerization(SI-ATRP) to improve the membrane’s hydrophilic property. The CMPES hollow fiber membrane was prepared by phase inversion process. The benzyl chloride groups on the CMPES membrane surface could afford effective macroinitiators for grafting the well-defined polymer brushes. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy confirmed the grafting of P (PEGMA) chains. Field emission scanning electron microscopy (FESEM) was used to characterize the surface morphology of the CMPES membrane and modified membrane. The grafting yield of P (PEGMA) was determined by weight gain measurement. The results showed that the number-average molecular weight (Mn) of P (PEGMA) increased with the polymerization time. It was found that the grafting of P (PEGMA) brought higher pure water flux, improved water uptake ratio and better anti-protein absorption ability to CMPES membrane after modification.
Charged mosaic membrane (CMM) has high water flux, low salt retention and high organic rejection. The tri-channel hollow fiber charged-mosaic membrane (CMM) was prepared by interfacial polymerization (IP). The tri-channel polysulfone (PSF) hollow fiber ultrafiltration(UF) membrane was used as the support membrane. Polyethylenimine (PEI), 2, 5-diamino-benzenesulfonic acid (DIA) and basic fuchsin (BF) were used as aqueous phase monomer. Trimesoyl chloride (TMC) was used as organic phase monomer. ATR-IR, scanning electron microscope (SEM) and gas sorption analyzer (GSA) were applied in structural analysis of CMM. The uniform design and SPSS were applied in membrane preparation and data analysis.The polymer ATR-IR spectroscopy shows IP occurrence between aqueous phase monomer and organic phase monomer. Polymer contains both sulfonate group and quaternary ammonium group. It show that the membrane has the feature of CMM. Regression equation was gained, and it shows the CMM retention would enhance with the concentration increase of DIA, PEI and SDS and decrease with concentration decrease of FB in experimental range. The composite layer can be observed from membrane SEM after IP. The CMM retention to NaCl, polyethylene glycol(PEG), Xylenol orange and Methyl chloride is12.4%, 90%, 96%,88% and 88.2% respectively.
Abstract. The effects of temperature and pH value on hydrolytic stability of Reactive Black 5, and the effects of pH buffer on pH value stability of dye solution and ink prepared by Reactive Black 5 are studied in this paper. The results show that the final pH value decrease with the increase of temperature, both elimination reaction rate and hydrolysis reaction rate of Reactive Black 5 increase with the increase of temperature, and elimination reaction is the main factor of affecting pH value of dye solution at low temperature, but hydrolysis reaction will become the main factor at high temperature. The increase of initial pH value can increase the decrease rate of pH value of dye solution in the beginning time, Reactive Black 5 can keep at equilibrium state of elimination reaction and hydrolysis reaction at the pH value of 4.4 and temperature of 40 °C, and the elimination reaction rate will increase with the increase of initial pH value at 40 °C. Adding pH buffers into dye solutions can significantly reduce the decrease extent of pH values, and the pH buffer of NaH2PO4/ Na2HPO4has the strongest ability of stabilizing pH value, the increase of amount of NaH2PO4/ Na2HPO4can reduces the decrease extent of pH value, and the initial pH value of dye solution increases with the increase of proportion of Na2HPO4in the pH buffer. When applied in ink, NaH2PO4/ Na2HPO4still has the strongest ability of stabilizing pH value while it has little effects on properties of ink.
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