This is a brief review of some recent progress in the development and application of firstprinciples electronic structure approaches for molecules in solution. In particular, it accounts for the background, theoretical features, and representative applications of a recently developed, truly accurate continuum solvation model which is known as Surface and Volume Polarization for Electrostatics (SVPE) or Fully Polarizable Continuum Model (FPCM) in literature. The FPCM-based first-principles electronic structure approaches have been widely employed to study a variety of chemical and biochemical problems and serve as an integrated part of various computational protocols for rational drug design. Some perspective of the future of the FPCM-based first-principles electronic structure approaches is also given.

We used the free energy perturbation (FEP) method to calculate the solvation free energy according to the mass action model. We did this to investigate the enthalpy-entropy compensation effect of surfactant molecular structures on micellization in solution. The thermodynamic properties of micellization in an aqueous solution for several alkyl aryl sulfonates are discussed. Results show that the solvation free energy calculated from the free energy perturbation is consistent with that from the surface tension method and can be used to discriminate between the capacities of micellization for alkyl aryl sulfonates. The micellization of alkyl aryl sulfonate in an aqueous solution is a spontaneous process and the micellization is enthalpy-entropy compensated. The compensation temperature was found to be (302± 2) K. As the aromatic ring shifts from the edge to the middle of the long carbon chain, the formation ability of the micelle and micelle stability decrease. However, with an increase in the number of carbon atoms on the short or long alkyl chains on the aromatic rings the formation ability and the stability of the micelles increase.

The A- and B-band electronic excitations and the excited state structural dynamics of 6-N,N-dimethyladenine (DMA) were studied by resonance Raman spectroscopy and density functional theory calculations. The π_H→π_L^* transition is the main part of the A-band absorption and its calculated oscillator strength occupies 79% of the A-band absorption. n→Ryd and π_H→Ryd transitions where Ryd denotes the diffuse Rydberg orbital play important roles in the B-band electronic transitions and their calculated oscillator strengths occupy about 62% of the B-band absorption. The oscillator strength for the π_H→π_L^* transition, which dominates the A-band electronic transition only occupies about 33% of the B-band absorption. The foundamental vibrations of the purine ring deformation stretch plus the C8H/N9H bend mode ν₂₃ and the 5 member ring deformation stretch plus the C8H bend mode ν₁₃, and their overtones and combination bands occupy most of the A-band resonance Raman intensities. Therefore, the ¹π_Hπ_L^* excited state structural dynamics of DMA is mainly along the ν₂₃ and ν₁₃ reaction coordinates. The majority of the B-band resonance Raman intensities are dominated by the fundamental vibrations of ν₁₀, ν₂₉, ν₂₁, ν₂₆, ν₄₀, and their overtones and combination bands. This suggests the B-band excited state structural dynamics of DMA is mostly along the purine ring deformation, the C6N10 stretch, the N9H/C8H/C2H bend and the N(CH₃)₂ antisymmetric stretch. The appearance of ν₂₆ and ν₁₂ in the A-band resonance Raman spectrum is correlated to the Franck-Condon region ¹nπ^*/¹ππ^* conical intersection. The activation of ν₂₁ in the B-band resonance Raman spectrum is correlated to the Franck-Condon region ¹ππ^*/¹πσ_N9H^* conical intersection.

We synthesized a novel histidine salt of 12-silicotungstate supramolecular compound ((HisH₂)₂SiW₁₂O₄₀·6H₂O) by a solution method. Its composition, thermostability, and structure were characterized by elemental analysis, thermal gravimetric and differential thermal analysis (TG-DTA), and single crystal X-ray diffraction, respectively. The experimental results show that the supramolecular compound has a composition of C₁₂H₃₄N₆O₅₀SiW₁₂ and it is stable under 135 °C in air. It belongs to a monoclinic system (space group C2/c) with a=2.44005(18) nm, b=1.29788(10) nm, c=1.86898(14) nm, β=124.0380(10)°, V= 4.9048(6) nm3, Z=4, and D_c=4.465 g·cm^-3. The final statistics based on F² are goodness-of-fit (GOF) = 1.268, R₁=0.0344 and wR₂=0.0851 for (I>2σ(I)). X-ray diffraction analysis further reveals that this supramolecular compound mainly consists of polyoxometalate anions [SiW₁₂O₄₀]^4-, protonated histidine cations [HisH₂]²⁺ and lattice water. A three-dimensional (3D) network is formed through hydrogen bonding. The resulting sample shows photochromism under UV irradiation. We propose a possible photochromic mechanism by an analysis of the chromic sample′s electron spin resonance (ESR) spectrum.

The geometric configurations of chlorin e6 and six designed e6 lysine amides were optimized using density functional theory at the B3LYP/6-31G^* level. Based on the obtained minimum energy structure, a single point calculation was carried out at the B3LYP/6-31G^** level. The electronic spectra of these compounds were calculated using time dependent density functional theory at the LSDA/6-31G^** level. The results indicate that the e6 lysine amides, in which the carboxyl of e6 connects with the ε-NH₂ of lysine, are more stable. Among them, the 15-acetamide Y_ε has the highest stability. The formation of lysine amides improves the water-solubility and leads to a slightly poor coplanarity of the chlorin macrocycle in e6. Therefore, the frontier orbital gaps of the e6 lysine amides are slightly higher than that of e6, causing the long wavelength absorption to a small blue-shift of 16-39 nm. The adsorption wavelength is still in the range of 600-900 nm for photodynamic therapy. Furthermore, the long wavelength absorption is strongly affected by the conformation of the molecule. By comparison with Y_ε, in which the lysine amide group and the chlorin macrocycle are almost coplanar, the planarity of the chlorin ring of Y_ε1 and Y_ε2, in which the lysine amide is almost perpendicular to the chlorin ring, is improved and results in red shifts of 53 nm and 50 nm for their long wavelength absorptions, respectively, the average adsorption wavelength of Y_ε, Y_ε1, and Y_ε2 is 18 nm larger than that of e6.

The geometries, stability, and electronic and magnetic properties of TbSi_n (n=2-13) clusters were systematically investigated using relativistic density functional theory (DFT) within the generalized gradient approximation. The average binding energies, dissociation energies, charge transfer, the highest occupied molecular orbital and the lowest unoccupied molecular orbital (HOMO-LUMO) gaps, Mulliken populations (MP), and magnetic properties were calculated and were discussed. The TbSi_n (n=2-13) clusters do not form encapsulated structures at n=10. We conclude that the stability of TbSin is consistent with the encapsulated geometric structure and also with the inherent electronic stabilization. Furthermore, results of the calculated Mulliken populations show that the charge always transfers from Tb to Si. The magnetic moment is largely located on Tb and is mainly populated by f-block electrons. The f electrons are very localized and to a large extent not responsible for chemical bonding. The partial density of states (PDOS) of TbSi₁₀ shows that there is strong sp hybridization between Tb and Si.

The electronic structures of ilmenite (IL)-type hexagonal ZnTiO₃ were investigated using the generalized gradient approximation (GGA) and local density approximation (LDA) based on density functional theory (DFT). The optical properties of ZnTiO₃ were also calculated by the LDA method. The calculated results were compared with experimental data. Results show that the structural parameters obtained by the LDA calculation are rather close to the experimental values. IL-type hexagonal ZnTiO₃ is a kind of direct bandgap (E_g=3.11 eV) semiconductor material at the Z point in the Brillouin zone. An analysis of the density of states (DOS) and the Mulliken charge population clearly reveal that the Zn―O bond is a typical ionic bond whereas the Ti―O bond, which is similar to the Ti―O bond in perovskites ATiO₃ (A=Sr, Pb, Ba), is covalent in character. Furthermore, the dielectric function, absorption spectrum, and refractive index were obtained and analyzed on the basis of electronic band structures and the DOS for radiation up to 50 eV.

We carried out a theoretical investigation into the mechanism of steam dealumination of the ZSM-5 zeolite and into the mechanism for the increase in the hydrothermal stability of the La-modified ZSM-5 zeolite. This was done using density functional theory (DFT) with 12T cluster models that simulated the local structures of the zeolite materials. We demonstrate that because of the hydrogen bond interaction between the first adsorbed water molecule and the ZSM-5 zeolite framework, the Al—O bond is weakened and elongated. As the second water molecule is adsorbed, the Al—O bond near the second water molecule is further weakened and eventually broken because of the hydrogen bond interaction between the second adsorbed water molecule and the ZSM-5 zeolite framework. As more water molecules are adsorbed, the other Al—O bonds are broken sequentially resulting in a dealumination of the ZSM-5 zeolite. The introduced lanthanum coordinates with four zeolite framework oxygen atoms, thickens the zeolite framework, moves over the framework Al atom, increases the steric hindrances and partially prevents polar water molecules from attacking the Al—O bond. These actions retard the weakening of the Al—O bonds and improve the hydrothermal stability of the ZSM-5 zeolite. The calculated adsorption and hydrolysis energies of the water molecule further confirm that the presence of lanthanum enhances the hydrothermal stability of the ZSM-5 zeolite.

We performed a molecular dynamics simulation to investigate the adsorption of uranyl ions onto the basal surfaces of kaolinite using a simulation cell containing 0.01 mol?L^-1 uranyl carbonate and 9× 9×3 kaolinite unit cells. The adsorption sites of the uranyl ions on kaolinite were clearly shown by serial snapshots and the coordination of uranyl ions to oxygen were determined using a radial distribution function. The adsorption trends of uranyl ions on two distinct basal surfaces were discussed using an atomic density profile. Outer-sphere complexation of uranyl on kaolinite was confirmed using the atomic density profile and the mean squared displacement. Confirmation of the outer-sphere complexation supports the theoretical simplification of the adsoption sites in the surface complexation model.

The assembly behavior of the nonionic surfactant Triton X-100 at the water/oil interface was studied at the mesoscopic level using a dissipative particle dynamics simulation. We extended the calculation method for interfacial tension from a binary water/oil system to a ternary system with surfactants. In particular, the simulated results of interfacial tension that were chosen for illustration are in excellent agreement with the experimental results. Additionally, we discuss the relationship between interfacial tension and interfacial density, which supports the synergistic theory of mixed surfactants. The microscopic information obtained from the simulated method will opens another door for the selection and application of surfactants in enhanced oil recovery.

Quantitative structure-activity relationships (QSARs) were used to design self-emulsifying delivery system. Ab initio calculations were carried out at the HF/6-31G^* level. The influences of component ratio, stereoscopic effect, hydrophobic interactions, and the electric effect on the microemulsion areas and the size of the self-emulsifying systems were investigated. The microemulsion areas and sizes were correlated to the generated descriptors and the ratio of the components using multiple linear regression analysis (MLR). Validation was carried out by a predictive-ability test. The ratio of surfactant to co-surfactant had the most impact on the phase behavior of the self-emulsifying systems. The size of the self-emulsifying system increased with an increase in the amount of oil and co-surfactant and decreased with an increase in the amount of surfactant. Interactions between the components had little influence on the properties of the systems. The models had significant predictive power except for the model of isopropyl myristate (IPM). QSARis a new method to investigate the preparation of self-emulsifying systems.

We report on a composite polymer electrolyte containing the ionic liquid 1-ethyl-3- methylimidazolium hexafluorophosphate (EMIPF₆). This composite polymer electrolyte is based on the poly(vinylidene fluoride-co-hexafluoropropylene) (P(VdF-HFP)) polymer matrix and is a potential electrolyte for use in lithium ion batteries. The ionic conductivity of the composite polymer electrolyte was measured by electrochemical impedance spectroscopy (EIS). Linear sweep voltammetry (LSV) was performed to investigate the electrochemical stability window of the polymer electrolyte. The thermal properties for the composite polymer electrolyte were also characterized by thermogravimetry (TG) and by a flammability test. The results show that the presence of the EMIPF₆ ionic liquid increases the ion transport properties greatly but a better cathodic stability is only obtained by the addition of organic additives such as ethylene carbonate-propylene carbonate (EC-PC), which extends the cathodic stability to 0.3 V. This corresponds to an electrochemical stability window of 0.3-4.3 V. The selected Li₄Ti₅O₁₂ anode and LiCoO₂ cathode materials exhibit acceptable electrochemical performance in combination with the prepared P(VdF-HFP)/ LiPF₆/EMIPF₆/EC-PC composite polymer electrolyte. At a charge-discharge rate of 0.1C, Li/LiCoO₂ and Li/ Li₄Ti₅O₁₂ have reversible capacities of 130 and 144 mAh·g^-1, respectively. However, the corresponding thermal performance is suppressed because of the presence of organic additives.

We prepared a Pt/C catalyst for use in proton exchange membrane fuel cells (PEMFCs) by pulse-microwave assisted chemical reduction synthesis. The microstructure and morphology of the as-prepared catalyst was characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The catalyst's electrocatalytic performance in the oxygen reduction reaction (ORR) was measured by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and constant potential polarization. The results indicate that pulse-microwave assisted chemical reduction synthesis is an efficient method to prepare PEMFC catalysts and that the pH and the microwave power largely influence the size and dispersion of Pt nanoparticles. At pH 10 and at a microwave power of 2 kW, the Pt nanoparticles were found to be uniform in size and the Pt nanoparticles size ranged between 1.3 and 2.4 nm with an average size of 1.8 nm. Additionally, the Pt nanoparticles were found to be highly dispersed on the surface of the carbon support. The electrochemical measurements showed that the electrochemical surface area (ESA) of the catalyst was 55.6 m²·g^-1 and the catalyst exhibited superior performance and stability in the ORR. The maximum power density of the single cell was 2.26 W·cm^-2·mg^-1 for the catalyst prepared at a microwave power of 2 kW and a pH of 10 as the cathode material. The maximum power density was higher than that of the catalyst prepared using a microwave power of 1 kW (2.15 W·cm^-2·mg^-1) and also higher than that of the catalyst from Johnson Matthey (1.89 W·cm^-2·mg^-1).

We prepared a new kind of N-doped amorphous carbon (C_xN) by the calcination of poly-o-toluidine (POT) at 800 °C. The prepared C_xN consisted of about 8.5% (w) nitrogen. Pd nanoparticles were deposited on C_xN because of the inherent chemical activity arising from nitrogen incorporation. The Pd/C_xN composite catalyst has a large electrochemically active surface area and it shows good electrocatalytic performance and stability toward methanol oxidation in alkaline media. All the results suggest that C_xN can potentially find application in fuel cells.

Hexagonal TiS₂ was synthesized as a high-capacity anode material for lithium ion batteries.X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicated that this material had a layeredstructure with particle sizes between 10 and 20 μm. It shows three discharge plateaus between 3.00 and0.00 V with a reversible capacity of up to 668 mAh·g^-1. It has excellent cycling performance between 3.00and 1.40 V. Particle pulverization and formation of Li₂S lead to performance degradation because of theirreversible dissolution of Li₂S into the electrolyte below 0.50 V. The addition of extra acetylene black and adecrease in particle size markedly improve the electrochemical performance of the TiS₂ anode.

La₄MgNi₁₉ alloys were prepared by induction melting under different heat treatment conditions. Phase structures and electrochemical properties of the alloys were investigated systematically by X-ray diffraction (XRD) and electrochemical experiments. A structural analysis of the alloys showed that all the alloys were composed of multiphases and the alloys obtained after water quenching at 900 °C consisted of a main LaNi₅ phase and a few unknown phases while the alloys obtained from the annealing treatment at 900 ° C consisted of Pr₅Co₁₉-type, Ce₅Co₁₉-type and few LaNi₅ phases. The electrochemical cyclic stability (S₁₀₀) of the water quenched and the anneal-treated alloys was 49.7% and 76.0%, respectively. The cyclic stability of the alloy electrodes is closely related to the phase structures. Annealing treatment was beneficial for the formation of Pr₅Co₁₉-type and Ce₅Co₁₉-type phases, La₄MgNi₁₉ alloys had worse electrochemical cycling stability than the La₃MgNi₁₄ alloys from the La-Mg-Ni system's hydrogen storage alloys.

(3-Mercaptopropyl)triethoxysilane (MPTES) was hydrolyzed in acid or basic ethanol-water solution. Fourier transform infrared (FTIR) spectroscopy was used to characterize the structures of MPTES solutions and MPTES films that formed on copper. The corrosion protective performance of the MPTES films was evaluated by polarization curves and electrochemical impedance spectroscopy (EIS). The results showed that MPTES was hydrolyzed to a certain extent with the formation of Si―OH groups in an acid silane solution and the degree of hydrolysis increased during the aging process of the solution at room temperature. However, a small amount of MPTES was hydrolyzed in the basic silane solution and a large number of SiOCH₂CH₃ groups were found in it. More Si ―O― Si bonds were formed in the film obtained from the acid silane solution compared to the film formed in the basic silane solution. The polarization curves showed that the MPTES films could decrease the corrosion current density of the copper electrodes; the protection efficiencies of the films were 90.3% (for the acid film) and 79.2% (for the basic film). EIS plots indicated that the basic film lost its protective capability after 24 h of immersion in 3.5% (w) NaCl solution while the acid film showed increasing impedance.

Polypyrrole (PPy) was chemically synthesized from pyrrole using sodium p-toluenesulfonate as a doping agent and ferric chloride as an oxidant on the surface of the AZ31 magnesium alloy. Fourier transform infrared (FTIR) spectroscopy was used for structural characterization of the PPy film. The corrosion behavior of the PPy coated AZ31 Mg alloy was studied using an electrochemical polarization test and electrochemical impedance spectroscopy (EIS). Scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDS) were used to observe the surface morphology and for elemental analysis of the film, respectively. The PPy film showed a certain corrosion inhibition on the AZ31 magnesium alloy. Silane pretreatment can improve the corrosion protection performance of the Mg/PPy system causing a positive shift of the corrosion potential by 110 mV and a decrease in the corrosion current density by two orders of magnitude compared with that of AZ31 Mg alloy.

We investigated the inhibition performance of a new imidazoline derivative inhibitor, TAI, which can be used as a gas-liquid two-phase inhibitor against CO₂ corrosion by weight-loss method, electrochemical impedance spectroscopy (EIS), Fourier-transform infrared (FT-IR) spectroscopy, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Results revealed that the thioureido imidazoline inhibitor was an effective inhibitor against CO₂ corrosion in gas and liquid two phases. Surface analysis by AFM showed that damage to the metallic surface was considerably reduced in the presence of the TAI inhibitor. A bigger adhesive force between the AFM probe and the steel surface was detected owing to hydrophobic interaction from the inhibitors in the two phases. The long range-repulsive force between the AFM probe and the steel surface increased in gas phase but decreased in liquid phase by the screening effect of surface charges. XPS and FT-IR spectroscopy proved that the adsorption films on the metal surfaces with protective properties of TAI and acid hydrolysis products of the TAI (amides) were present in liquid phase and in gas phase, respectively. The above results further confirmed the hydrolysis mechanism of imidazoline derivatives in acid solution.

The initiation, growth, and temporal and spatial distribution of localized corrosion of Q345B carbon steel in carbonated concrete pore solutions (pH 9.6) containing 0.1 mol·L^-1 Cl^- ions were investigated using a potential and galvanic mapping technique based on a wire beam electrode (WBE). Different mechanisms for repair and suppression on the stable localized corrosion by tetraethylenepentamine (TEPA) and nitrite were compared. The results indicate that nitrite can inhibit the active dissolution of steel beneath the rust layer because of the fast penetration of nitrite into the rust layer. However, TEPA can promote active dissolution under the rust layer initially because of its slow penetration rate through the rust layer. The localized active dissolution was only refrained after a long time because of TEPA molecules permeating into the interface between the rust layer and the steel matrix. Electrochemical impedance spectroscopy (EIS) was useful in allowing us to determine how the localized corrosion was initiated but failed to indicate the heterogeneous adsorption of the inhibitors on steel. A new localized corrosion factor (LF) based on galvanic mapping is proposed and is shown to be effective for the characterization of the localization of corrosion and the inhibition effect of inhibitors on localized corrosion.

TiO₂-MoO₃ composite nanotube thin films were obtained by the thermal treatment of titanium dioxide nanotube thin films in the presence of MoO3. Titanium dioxide nanotubes (TiO₂ NTs) thin films were prepared by the anodic oxidation of titanium foil. The resultant thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), Mott-Schottky analysis, and photoelectrochemical methods. The XRD patterns showed that an anatase type TiO₂ was present in the thin films. Nanotube structures for the thin films were observed by SEM. MoO₃ was dispersed on the TiO₂ NT top surface. Elemental analysis by XPS showed that MoO₃ recombined with the TiO₂ NTs to form TiO₂-MoO₃ composite nanotube thin films. The influence of time and temperature of thermal treatment on the photoelectrochemical response for the TiO₂-MoO₃ composite nanotube thin film electrodes were investigated. The photoelectrochemical response of the TiO₂-MoO₃ composite nanotube thin film increased under visible light illumination compared with the pristine TiO₂ NTs. The highest photoelectrochemical response was observed for the TiO₂-MoO₃ composite nanotube thin film obtained by thermal treatment at 450 °C for 60 min.

A cyanide-free alkaline copper deposition bath was developed using methylene diphosphonic acid (MDPA, H₄L) as a complexing agent for Cu²⁺. The plating bath was investigated using potentiometric titrations, voltammetric curves, and polarization curves. The potentiometric titration gave dissociation constants for MDPA of: pK₁=1.86, pK₂=2.65, pK₃=6.81, pK₄=9.04, and the stability constants were: pK_ML= 10.65, pK_ML2 = 5.59, pK_ML3 = 2.50. Three different complex species were present in the bath as the pH increases: Cu(H₃L)₂, [Cu(H₃L)(H₂L)]^-, and [Cu(H₂L)₂]^2-. MDPA was found to be more likely to form complex species with Cu²⁺ than 1-hydroxyethylene-1,1-diphosphonic acid (HEDPA) from pH 7 to pH 10. At pH 9, [Cu(H₃L)(H₂L)]^- and [Cu(H₂L)₂]^2- were reduced to Cu at the cathode. Compared with the HEDPA system at 10 °C the peak potential shifted to more negative values and the rate of diffusion was faster.

The effect of the ionic liquid additive 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM] HSO₄) on the kinetics of oxygen evolution during zinc electrowinning from an acidic sulfate solution was investigated. We used potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy, and X-ray diffraction for this study. Potentiodynamic polarization curves and the corresponding kinetic parameter analysis show that [BMIM]HSO₄ has a catalytic effect on oxygen evolution by stimulating the reaction rate constant. Impedance data reveal that [BMIM]HSO₄ can markedly reduce the oxygen evolution charge transfer resistance. The addition of 5 mg·L^-1 [BMIM]HSO₄ obviously decreased the resistance value by at least 50% over the studied potential range from 1.85 to 2.10 V. In addition, the results of the impedance measurements also suggest an inhibition effect of [BMIM]HSO₄ on the secondary reactions and this is due to the adsorption of the additive on the anode surface, which decreased the amount of active sites for anion adsorption. All electrochemical results were corroborated with a morphological and orientation analysis of the anodic surface after 120 h of anodic polarization. The addition of [BMIM]HSO₄ inhibited the generation of the intermediate product β-PbO₂ and it promoted the generation of larger, loose, and porous α-PbO₂, which benefited the oxygen evolution reaction.

Interactions between DNA and the cationic gemini surfactant hexamethylene-1,3-bis(dodecydimethylammonium bromide) (12-6-12) in an aqueous solution were investigated using UV-Vis spectroscopy, zeta potential, fluorescence emission spectroscopy, dynamic light scattering, and agarose gel electrophoresis. It could be found that interactions between DNA and the cationic gemini surfactant were stronger than interactions between DNA and traditional surfactant due to the special structure of gemini surfactant. The cationic gemini surfactant can interact with DNA at very low concentrations and micellelike structures form around the DNA chains. The micelle-like structure of 12-6-12 that is induced by DNA appears at the critical aggregation concentration (CAC). The CAC is two orders of magnitude lower than the critical micelle concentration (CMC) of 12-6-12 in a DNA-free solution. The CAC is independent of DNA concentration but it is dependent on the hydrophobic interaction between surfactant molecules and the electrostatic attractive interaction between the surfactant and DNA. Zeta potential and gel electrophoresis show that the negative charges of DNA are neutralized effectively and the zeta potential of the complex changes from negative to positive values. Atomic force microscopy (AFM) images show loose structures, beadlike structures (nucleosomes), and globe structures. Circular dichroism (CD) spectra show that the secondary structure conformation of DNA changes because of its interaction with 12-6-12.

The redox behavior and the potential dependent adsorption structure of alkylated viologen on a Cu(100) electrode were investigated by cyclic voltammetry (CV) and in situ scanning tunneling microscopy (STM). Heptyl viologen (1,1'-diheptyl-4,4'-bipyridinium dichloride) (DHV) and ethyl viologen (1,1'-diethyl-4, 4'-bipyridinium dibromide) (DEV) showed different current waves during CV measurements in a KCl-containing electrolyte solution. The dicationic heptyl viologen molecules showed a highly ordered two dimension (2D)‘dot-array’structure on the c(2 × 2)-Cl modified Cu(100) electrode surface in the STM images while the dicationic ethyl viologen molecules did not show any structures. With a decrease in the electrode potential, a one-electron reduction of the dication heptyl viologen resulted in the appearance of a stripe pattern that was formed by radical heptyl viologen as shown in the STM images. A more compact stripe pattern was visible in the radical ethyl viologen phase. The adsorption structure of heptyl viologen strongly depends on the electrode potential but the structure of the ethyl viologen adsorbed on the Cu(100) electrode was less response to the electrode potential.

Au/SnO₂ catalysts were prepared by deposition-precipitation (DP), co-precipitation (CP) and typical wet impregnation methods (IM). M(M=Pt, Pd)-promoted Au/SnO₂ catalysts were prepared by the DP method. The samples were characterized by X-ray diffraction (XRD), Brunaner-Emmett-Teller (BET) adsorption, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) techniques. The results showed that compared with CP and IM, the DP method led to a fairly uniform dispersion of gold nanoparticles with diameters less than 5 nm and larger specific surfaces for the Au/ SnO₂ catalyst. The Au in Au/SnO₂-DP was metallic (Au⁰) while in Au/SnO₂-CP and Au/SnO₂-IM the Au consisted of a mixture of Au⁰ and Au³⁺. The oxidation of carbon monoxide over the Au/SnO₂-DP and Mpromoted Au/SnO₂-DP catalysts were investigated. We observed that the Pd- or Pt-doping of Au/SnO₂-DP resulted in a significant increase in performance. We conclude that the different activities of the Au/SnO₂ catalysts that were prepared using different preparation methods may be attributed to the size of the Au particles and the states of gold. A remarkable improvement in catalytic activity because of Pd or Pt doping was associated with strong interactions between Pd or Pt and Au.

We synthesized WO₃ doped mesocellular silica foam (WO₃-doped MCF) catalysts with a high tungsten oxide content of 20% (w, mass fraction) directly using sodium tungstate and tetraethylorthosilicate as precursors. The catalysts showed high thermal stability after calcination at 773 K. Small-angle X-ray scattering, N₂ adsorption, and transmission electron microscopy results indicated that the characteristic three dimensional mesocellular structural features of the MCFs were retained after the incorporation of tungsten oxide species. Ultraviolet-Raman and ultraviolet-visible diffuse reflectance spectroscopy data showed that isolated or lowly condensed oligomeric tungsten oxide species were obtained for the WO₃- doped MCF catalysts. These oxide species were stable and highly dispersed in the silica-based MCF matrix with a tungsten oxide content lower than 20% (w). We found that the nature of the tungsten species largely depended on its content and the direct synthesis method was beneficial in obtaining highly dispersed tungsten oxide species. In the selective oxidation of cyclopentene (CPE) to glutaraldehyde (GA), the 20% (w) WO₃-doped MCF catalyst had a CPE conversion of 100% and a GA yield of 83.5% after reacting for 16 h. Furthermore, very stable catalytic activity after many recycling tests was apparent for the WO3-doped MCF catalyst indicating that almost no tungsten species was leached into the reaction solution. A proper amount of tungsten oxide and its high dispersion accounted for the high activity.

We systematically studied the surface acid-base properites and complexation behavior of heavy metal ions in aqueous suspensions of α-Fe₂O₃, γ-Al₂O₃, SiO₂ of mixed oxides and the α-Fe₂O₃/γ-Al₂O₃/ SiO₂ mixed systems using potentiometric titrations in combination with computer-based calculations using the constant capacitance model (CCM). The experimental and calculated results reveal that the surface chemical reactions in the mixed system are quite different from the sum of the individual single systems. A complicated mutual interaction exists among these mineral surfaces. The surface chemical reaction models and relevant equilibrium constants in the mixed system are: ≡XOH₂⁺?≡XOH+H⁺(lgK_a1=-4.23), ≡XOH?≡XO^-+H⁺(lgK_a2=-8.41). The surface complexation model and related equilibrium constants for Cu²⁺, Pb²⁺, and Zn²⁺ in the mixed system can be described by following reaction: ≡XOH＋M²⁺ ?≡XOM⁺+H⁺, with lgK of -2.20, -1.90, -3.20 for Cu²⁺, Pb²⁺, Zn²⁺, respectively.

Self-assembled ZnO thin films with controlled sizes were successfully prepared by varying the processing parameters. The films have a photonic band gap, which extends the absorption range to the visible light region. The photocatalytic activities of the ZnO thin films were evaluated by the degradation of methyl orange (MO). The crystal structure of ZnO was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the ZnO thin films exhibit good photocatalytic activities under sunlight. Furthermore, the photocatalytic activities of the ZnO thin films were highly dependent on sphere size. With an increase in ZnO sphere size, the degradation efficiency toward MO decreased. The photodegradation can be described using a pseudo-first-order kinetics equation.

A series of peripherally substituted free base corroles (1, 2, 3, 4) and their gallium complexes 1-Ga(Py), 2-Ga(Py), 3-Ga(Py), 4-Ga(Py) were synthesized and characterized by proton nuclear magnetic resonance (¹H NMR), UV-visible (UV-Vis) spectroscopy and electrospray ionization mass spectra (ESI-MS). The UV-visible spectra, steady state fluorescence spectra，and time resolved fluorescence spectra of the free base corroles and their gallium complexes were recorded in different solvents. Fluorescence lifetimes were obtained by fitting fluorescence decay kinetics curves using a single exponential simulation. The effects of non or weak polar solvents on the UV spectrum of gallium corrole were fitted to the Bayliss equation and the non-radiative energy loss hc(ν¹_A-ν_F) of gallium corrole and F(n) showed a linear correlation.

Glycogen synthase kinase-3β(GSK-3β) is a kind of serine/threonine protein kinase. It regulates the synthesis of glycogen and plays an important part in several signal pathways. It is believed to be an important target for a number of diseases such as diabetes, cancers, chronic inflammation, and Alzheimer's disease. Mg²⁺ ions are conserved structural metal ions in GSK-3β and they interact with adenosine-triphosphate (ATP). They are very important in phosphoryl transfer in the kinase. In this paper, the effect of two Mg²⁺ ions (Mg²⁺_I, Mg²⁺_II) on GSK-3β is illustrated. Mg²⁺ can stabilize the conformation of GSK-3β and ATP. Without Mg²⁺, the stabilization of GSK-3β reduces explicitly and the conformation of ATP changes. Mg²⁺_I is important in the phosphorylation reaction while Mg²⁺_II is essential and Lys183 alone cannot maintain the conformation of ATP without the assistance of Mg²⁺_II . ATP forms intramolecular hydrogen bonds and adopts a folded conformation when both Mg²⁺_I and Mg²⁺_II are absent.

Molecular dynamics simulations of α-tocopherol in a number of saturated phospholipid bilayers were performed at 280, 310, and 350 K. The phospholipids contained either short acyl tails, i.e., dimyristoylphosphatidylcholine and dimyristoylphosphatidylethanolamine or long acyl tails, namely distearoylphosphatidylcholine and distearoylphosphatidylethanolamine. The preferential position, hydrogen bonding, orientation, and dynamic properties of α-tocopherol in the bilayers were examined in detail and several conclusions were made. First, the hydroxyl group of α-tocopherol generally remains beneath the interfacial region of the lipid bilayers and it shifts toward the bilayer mid-plane with an increase in temperature. At 350 K it flip-flops between the upper and lower leaflets in the four lipid bilayers. Second, α-tocopherol mainly forms hydrogen bonds with the carbonyl ester oxygen in the lipid head groups and hardly forms hydrogen bonds with the amino groups in the phosphatidylethanolamine (PE) bilayers. Hydrogen bonding with PEs is more stable than hydrogen bonding with phosphatidylcholines (PCs) at low temperatures. Third, α-tocopherol's head group has fluctuating tilt angles relative to the normal of the lipid bilayers and the tail has many different conformations. Fourth, the lateral diffusion rate of α-tocopherol is comparable to that of phospholipid molecules at low temperature and it diffuses much faster than lipids at 350 K. The diffusion rate in the direction perpendicular to the membrane surface is much slower than the lateral diffusion rate.

We investigated the influence of carbon nanotube (CNT) size using CNTs including CNT(6,6), CNT(7,7), CNT(8,8), CNT(9,9), CNT(10,10), and CNT(11,11), and the influence of draw solution concentrations, such as 2.5, 3.75, and 5.0 mol·L^-1, on the permeation behaviors of salt and water molecules through the biomimetically manufactured forward osmosis (FO) membranes. Nanosecondscale molecular dynamic simulations were carried out to obtain the relevant information, including the distributions of the water molecules, water flux, and salt permeation within the different CNT membranes. Simulation results show that the FO membrane incorporating CNT(8,8) can achieve the highest water flux and also the lowest salt permeation.

Carboxylic-functionalized multiwalled carbon nanotube (MWCNT-COOH) is obtained by oxidation with potassium bichromate and further modification by amide condensation afforded aminopyridine-grafted MWCNT (MWCNT-AP). The MWCNT-AP was characterized by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (¹H-NMR) and X-ray photoelectron spectroscopy (XPS). Transmission electron microscopy (TEM) results suggest that MWCNTCOOH aggregates in ethanol and that MWCNT-AP is stable and well dispersed in solution. Horseradish peroxidase (HRP) physically adsorbed onto the surfaces of MWCNT-AP and MWCNT-COOH and the adsorption amounts were 187.5 and 153.0 μg·mg^-1, respectively. UV-Vis spectra showed that the Soret band of HRP red-shifted markedly after adsorption onto MWCNT-AP or MWCNT-COOH indicating that the binding site of MWCNT-AP or MWCNT-COOH is near the heme pocket of HRP. Circular dichroism spectral results demonstrate that the secondary structure of HRP is influenced by MWCNT-AP. Enzyme-kinetic studies show that MWCNT-AP may adsorb HRP and its substrate 3,3',5,5'-tetramethylbenzidine (TMB) effectively, and the maximum reaction rate (V_max) of HRP increases significantly after interaction with MWCNT-AP.

Positively charged organic-functionalized α-Al₂O₃ ceramic hollow fiber was obtained by dip-coating the substrate with a 3-aminopropyl-(diethoxy)methylsilane (ADMS) solution. Negatively charged NaA zeolite particles were deposited on the substrate surface and used as seed for further secondary growth by the electrostatic adsorption of a positively charged organic-functionalized substrate and NaA zeolite particles. The NaA zeolite membrane was synthesized on a porous α-Al₂O₃ ceramic hollow fiber support by the microwave heating-secondary growth method. The as-synthesized NaA zeolite membranes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), zeta potential, and gas permeation tests. The differences in morphology, structure, and gas permeability between the NaA zeolite and the ADMS-modified substrate supported NaA zeolite membrane were determined. XRD results show that only NaA zeolite is present on the support. The zeta potential results indicate that opposite charges exist between the NaA zeolite seed or precursor and the organic-functionalized substrate surface, which confirms the electrostatic adsorption between them. SEM images show that a smooth and dense membrane (5 μm thick) is obtained and the particles are twinborn by good intergrowth on the ADMS-modified substrate supported NaA zeolite membrane surface. Gas permeation tests with H₂, O₂, N₂, and C₃H₈ at different temperatures show that the permeability of H₂ on the ADMS-modified substrate supported NaA zeolite membrane at 35 °C is 3.6×10^-7 mol·m^-2·s^-1·Pa^-1, which is lower than that (4.0×10^-7 mol·m^-2·s^-1·Pa^-1) of the NaA zeolite membrane. The ideal permselectivity of H₂/C₃H₈ is 11.25, which is far higher than that (5.06) of the NaA zeolite membrane.

C-Al₂O₃-TiO₂ nanocomposites with a dual pore system were synthesized via the sol-gel tri-constituent co-assembly process using an amphiphilic triblock copolymer F127 (PEO₁₀₆PPO₇₀PEO₁₀₆, M_W=12600) as a template, aluminum isopropoxide and tetrabutyl titanate as metallic sources and resol as an organic precursor. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and nitrogen adsorption/desorption were used to characterize the structures of these nanocomposites. The results show that the nanocomposite with a Al/Ti molar ratio of 1:10 has ordered mesoporous structures with a dual system of 3.9 and 6.5 nm, a high specific surface area of 259 m²·g^-1 and a pore volume of 0.37 cm³·g^-1. Low infrared emissivity coatings were obtained using the ethylenepropylene- diene monomer (EPDM) as an adhesive and the ordered mesoporous C-Al₂O₃-TiO₂ nanocomposites as a filling. As the Al/Ti molar ratio and coat thickness changed the infrared emissivities changed from 0.450 to 0.617.

We studied the interaction between CdSeS quantum dots (QDs) and gold nanoparticles (AuNPs) in solution. We found that the photoluminescence (PL) intensity of the QDs was efficiently quenched by the AuNPs with extraordinarily high Stern-Volmer quenching constant (K_sv) values that approach 108 L·mol^-1. The quenching efficiency is strongly related to the spectral overlap and the distance between the QDs and AuNPs and is independent of solvent polaritym, ion strength, and pH value. These results suggest that this superquenching behavior can be attributed to a long-range (Förster-type) energy transfer. Our findings allow for the design of exquisite multiple örster resonance energy transfer (FRET)-based biosensors for the highly sensitive and simultaneous monitoring of multiple molecules in live cells.

Amethod to graphitize amorphous carbon was carried out by annealing pyrocarbon from cracked phenolic resin in molten sodium metal at a lower temperature and ambient pressure and the phase transformation of pyrocarbon from amorphous carbon to crystallized carbon was studied. X-ray diffraction (XRD), Raman scattering spectroscopy, transmission electron microscopy (TEM), and nitrogen gas physisorption by the Brunauer-Emmett-Teller (BET) method were used to probe the prepared samples for carbon composition, particle size, and morphology. The graphitization of amorphous carbon was obvious when being annealed in molten sodium metal in argon atmosphere at 800 °C for 24 h. For the sample annealed at 900 °C for 24 h, the degree of graphitization was 40%and the average thickness of the graphitized carbon layers was about 40 nm. The effect of sodium metal infiltration into the matrix of amorphous carbon on the graphitization is also discussed.