Search

Four cyclodextrins (CD) including &beta, cyclodextrin (&beta, CD), &gamma, cyclodextrin (&gamma, CD), heptakis-O-(2-hydroxypropyl)-&beta, cyclodextrin (HP-&beta, CD), and heptakis-O-(2, 6-di-O-methyl)-&beta, cyclodextrin (DM-&beta, CD) were used as solubilizer to study the solubility enhancement of myricetin. The results of the phase solubility study showed that the presence of CDs could enhance the solubility of myricetin by forming 1:1 complexes. Among all CDs, HP-&beta, CD had the highest solubilization effect to myricetin. The concentration of myricetin could be 1.60 &times, 10&minus, 4 moL/L when the presence of HP-&beta, CD reached 1.00 &times, 2 moL/L, which was 31.45 times higher than myricetin&rsquo, s aqueous solubility. Subsequently, the HP-&beta, CD:myricetin complex was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). In order to get an insight of the plausible structure of the complex, molecular docking was used to study the complexation process of HP-&beta, CD and myricetin. In the complex, the A ring and C ring of myricetin were complexed into the hydrophobic cavity of HP-&beta, CD, while the ring B was located at the wide rim of HP-&beta, CD. Four hydrogen bonding interactions were found between HP-&beta, CD and -OH groups of the guest in the HP-&beta, CD: myricetin complex. The complexation energy (△E) for the host-guest interactions was calculated with a negative sign, indicating the formation of the complex was an exergonic process. A 30-ns molecular dynamics simulation was conducted to the HP-&beta, CD: myricetin complex. Calculation results showed that no large structural deformation or position change were observed during the whole simulation time span. The average root-mean-square deviation (RMSD) changes of the host and guest were 2.444 and 1.145 &Aring, respectively, indicating the complex had excellent stability.

Polyaniline (PANI) polymer coating was electrochemically synthetised by cyclic voltammetry (CV) method on stainless steel bipolar plates of proton exchange membrane fuel cell (PEMFC). Structure and morphology of PANI polymer coating were characterized by means of fourier transform infrared reflection (FTIR) spectrum and scanning electron microscopy (SEM). The corrosion behavior of the coating was evaluated by polarization curve and electrochemical impedance spectroscopy (EIS) in the medium of 1M H2SO4and 2ppM NaF at 70°C to simulate the corrosive condition of PEMFC. It was found that the optimal conditions for PANI polymer coating synthesis could be 10-15 circles when the voltage ranged from-1.2V to +1.2V(Vs.SCE) with a scan rate of 50 mV/s. SEM observation results indicated that the polymer coating presented with uniform and dense feature. FTIR results illustrated that the coating were composed of PANI. Corrosion current densities of 316L SS and PANI-coated steel were 10-5and 10-6A/cm2respectively. Corrosion potential of the coated SS shifted towards more positive values compared to the uncoated plate. EIS results indicated that the radius of the capacity impedance for PANI increased obviously.

N-heptyl-pyridine tetrafluoroborate is prepared by the double decomposition reaction of HEPB and NaBF4. The ionic liquid at room temperature used in the experiment has a significant absorption determined by UV spectrum within the range of 200-400nm, the maximum absorption wavelength of HEP-BF4ionic liquid in ethanol is 244nm. The standard working curve of HEP-BF4ionic liquid is y=0.00441+0.01563x (R=0.99912). The linear range of HEP-BF4ionic liquids in the ethanol is 1-75 mg/L. The recovery rate of HEP-BF4ionic liquid which is between 96.6% and 102%, is measured by standard addition method in ethanol.

The thermal conductivity at (220 to 480) K of anodic alumina film of (1.4 to 5) μm thick and about 30 % porosity, which is grown from aluminum foil, is reported. A laser flash technique was employe...