To address problems such as aging, mutation, and cancer, it is of great importance to understand the damage mechanism of DNA induced by hydroxyl radical. In this study, the abstraction reaction mechanism of hydroxyl radical with guanine-cytosine (GC) base pair in aqueous phase under the polarized continuum model (PCM) has been explored by using density functional theory (DFT). The results indicated that all the abstraction reactions in GC base pair were thermodynamically exothermic, and the stability of dehydrogenation radicals decreased in the order of (H2b-GC)^·>(GC-H4b)^·>(GC-H6)^·>(GC-H5)^·~(H8-GC)^·. The reaction energy of H2b abstraction pathway was the lowest among all investigated pathways, thus indicating that the reaction conversion of (H2b-GC)^· was the highest. In the five hydrogen abstraction pathways, the local energy barriers with respect to the corresponding reactant complexes increased in the following order: H2b

Salicylic acid (SA) was successfully grafted onto nano-TiO₂ surfaces (TiO₂-SA) by post-treatment surface modification. The effects of ultrasound stiring, solvents, material ratio, pH value, and temperature on the grafting process and photocatalytic material properties were investigated, and the grafting reaction kinetics was determined. The structures of the materials were determined using Fourier transform infrared (FT- IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). A structural model was proposed. The properties of the photocatalytic material were examined using contact angle analysis, simultaneous thermogravimetry-differential scanning calorimetry (TG-DSC), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), and scanning electron microscopy (SEM). Compared with bare TiO₂, the modified TiO₂ had od hydrophobicity and dispersion properties, a lower sedimentation velocity in solvents, better adsorption stability at oil-water interfaces, and extended visible light absorption. The TiO₂-SA gave excellent photocatalytic performances in nitrobenzene degradation under ultraviolet-light irradiation.

Molecular dynamics simulation was used to study the effect of the outer-wall on water flux in the inner channel by varying the inter-layer spacing of unconventional double-walled carbon nanotube (DWCNT) under reverse-osmosis conditions. Salt rejection and the water transport behavior inside the DWCNT were also examined. In the simulation, 0.5 mol·L^-1 NaCl aqueous solution was used to mimic seawater, and the chiral index of the inner-wall was fixed at (8, 8). A constant force on the salt solution produced pressure. Calculation of the number density profile of ions along the DWCNT axis showed that the water could be separated completely from the NaCl aqueous solution in some types of DWCNTs studied. Analyses of the hydrogen-bond lifetime, potential of mean force, and dipole moment distribution of the water molecules inside the DWCNT showed different permeabilities by water molecules and ions. An increase in the inter-layer spacing improved water flow in the DWCNT, which decreased the salt rejection performance. Finally, it was found that DWCNT with an inter-layer spacing of 0.815 nm gave the optimum balance between water flux and salt rejection. This study provides a molecular insight into the use of DWCNT in desalination, and will enable the design of improved reverse-osmosis membranes with high performance in terms of salt rejection and water permeability.

Density functional theory (DFT) and classical molecular dynamics simulations were used to study the effects of the interactions between zwitterionic alanine and some ions (Na⁺, Cu²⁺, Zn²⁺, and Cl^-) in saline solution on the association of alanine molecules. The DFT calculation results show that the association of alanine with these ions can enhance charge separation of zwitterionic alanine. Classical molecular dynamics simulation results also show that three associated structures of zwitterionic alanine molecules are present in alanine aqueous solution, and the associations can be weakened to a certain extent by the interactions between the cations/anions and alanine polar groups. The interaction between a cation and the carboxyl group of alanine can be greatly affected by hydration of the cation in dilute saline solution. The interaction between Cu²⁺ and alanine is much stronger than that between Na⁺ and alanine in the gas phase, but the situation is reversed in dilute aqueous solution, because the hydration of Cu²⁺ is much stronger than that of Na⁺. In dilute ZnCl₂ aqueous solution, the interaction between Zn²⁺ and the carboxyl group of the alanine molecule is less direct, because of the first hydration shell of Zn²⁺. However, indirect interactions between Zn²⁺ and alanine still lead to a decreased association among alanine molecules. In addition, the interactions of cations/anions with alanine not only weaken the association between alanine molecules, but also result in transformation between two typical conformations of associated alanine molecules. The ion concentration affects the conformations of associated cation/anion-alanine species, and associated alanine molecules.

Molecular dynamics simulations of oxygen molecules in NaOH and KOH solutions at different temperatures (25-120 ℃) and concentrations (1:100-1:5, molar ratios) were performed in this study. The interactions of oxygen molecules with the surrounding solvent and solute were clarified by considering the solvent-solvent, oxygen-solvent, and oxygen-solute radial distribution functions. The self-diffusion coefficients of the oxygen molecules and the solute were both determined by analyzing the mean-squared displacement (MSD) curves, using Einstein's relationship. It was concluded that at all concentrations, the diffusion coefficient of oxygen in NaOH solution is smaller than that in the corresponding KOH solution. The diffusion coefficients for hydroxide, Na⁺, and K⁺ decrease with increasing solute concentration, following similar trends to those of oxygen. The oxygen diffusion coefficient obtained in this study is in od agreement with the reported experimental value, suggesting that MSD is an attractive approach to study the oxygen diffusion behavior in strong alkaline solutions at elevated temperatures, which are experimentally extremely challenging.

The structures and spectroscopic constants of Zn₂ and Cd₂ were studied using the coupled-cluster theory with spin-orbit coupling based on the two-component relativistic effective core potential and matched basis sets aug-cc-pvnz-pp (n=Q, 5), combining complete basis set extrapolation of the electronic correlation energy and fourth-order polynomial fitting technique. Spin-orbit coupling was included in the post-Hartree-Fock procedure, i.e., in the coupled-cluster iteration, to obtain more reasonable results, although the spin-orbit coupling effect observed in Zn₂ and Cd₂ is not visible as it is in Hg₂. Our theoretical results agree well with the latest experimental values and other groups' theoretical results, and will be helpful in understanding the spectral characteristics of these two dimers.

ABaTiO₃ ceramic was synthesized using a conventional solid-state reaction, and sintered at 1400 ℃ for 4 h. The pure tetra nal phase was confirmed by Rietveld refinement of the X-ray diffraction data. The Raman spectrum and the far infrared (FIR) reflective spectrum were obtained and analyzed using Lorentz fitting and the four-parameter semi-quantum model fitting, respectively. The Raman and FIR spectra were assigned based on first-principles calculations, and consideration of the splitting of the transverse optical modes and longitudinal optical modes. All the vibrational modes were represented by linear combinations of the symmetry coordinates deduced by group theory analysis. Among the 12 optical modes, the Raman-active-only mode, B₁, can be viewed as the wing-flapping vibration of the O4-O5 plane perpendicular to the z-axis in the O₆ octahedron. The A₁⁽¹⁾ mode and the E⁽¹⁾ soft mode are split by the triply degenerate F_1u mode of cubic BaTiO₃, resulting in the ferroelectric property of tetra nal BaTiO₃. The appearance of the A₁⁽¹⁾ mode leads to crystal polarization along the z-axis and the E₍₁₎ mode causes the large permittivity. These two modes can be described as vibration of the Ti atom against the O₆ octahedral cage along the z-axis [A₁⁽¹⁾] and on the xy-plane [E₍₁₎].

The stability of anionic trans-dioxo manganese(V) corrole complex and the protonated species structure were investigated using density functional theory (DFT) with B3LYP method. The calculation results show that trans-dioxo manganese(V) corrole complex has one σ and two π orbitals in its O=Mn=O bonds, which are composed of the d orbital of the manganese atom and p orbitals of the two oxygen atoms. Enhancement of the electron-withdrawing ability of substituents results in a decrease in the O=Mn=O bond lengths, and shifts the O=Mn=O Raman stretching vibration to a higher wavenumber. On protonation, one of the axial oxygen atoms gains two protons and is transformed into a water molecule. The manganese atom then cannot hold water tightly to form effective coordination bonds with water. This results in irreversible protonation of the trans-dioxo manganese(V) corrole complex, which leads to formation of an oxomanganese (V) corrole complex.

Density functional theory calculations were performed to study the mechanism and reactivity of methanol oxidation mediated by Pt_nRu_m (n+m=3, n≠0) clusters. The potential energy surfaces and pathways of the initial O―H and C―H bond activations were predicted. The results show that the activation of methanol proceeds preferentially along the C―H bond activation pathway. The calculated reactivity order was Pt₂Ru>Pt₃> PtRu₂. Frontier molecular orbital analysis showed that the initial C/O―H bond activation is a proton transfer process. The solvent effect was also investigated. This study will enable a deeper understanding of C/O―H bond activation and provide new ideas for catalyst selection and optimizing conditions for methanol activation.

The magnetic properties of the antiferromagnetic complex μ-1,3-N₃-Ni(II)[LNi₂(N₃)](ClO₄)₂ (L= pyrazolate) were investigated using density functional theory (DFT) calculations combined with the broken symmetry approach. The calculation results obtained using the hybrid density functional theory (HDFT) agree well with the experimental data, and accurately describe the magnetic properties of complex. The large energy splitting, 0.93-0.99 eV, between singly occupied molecular orbitals indicates that there is strong non-degeneracy between them, and the two coupling paths (azido and pyrazolate) in the complex show that there is overlap between the p orbitals of the N atoms. All these factors contribute to the antiferromagnetism of the complex. The magnetic properties of the complex are also closely related to the dihedral angle τ of Ni-N-N-N-Ni. The antiferromagnetism of the complex increases as τ decreases from -55.38° to -1.5°; the maximum absolute value of magnetic coupling constant (J_ab) occurs at -11.95° (J_ab=-151.02 cm^-1). During this process, the coplanarity of the seven-membered ring, which consists of two Ni(II), one azido, and two bridging nitrogen atoms (N(4) and N(5)), is enhanced, i.e., coplanarity increases the antiferromagnetism of the complex.

The effects of sulfate concentration on the open circuit state and anodic polarization behavior of iron in dilute bicarbonate solutions were investigated using immersion tests, electrochemical measurements, and surface analysis techniques. In the absence of sulfate or in the presence of a low concentration of sulfate in dilute bicarbonate solutions, iron was in a passive state, with a corrosion potential of (-0.225±0.005) V. A high electrochemical impedance and low corrosion rate were obtained. No obvious active-passive transition was observed in the anodic polarization curves. In the presence of a high concentration of sulfate in dilute bicarbonate solutions, iron was in an active dissolution state, with a corrosion potential of (-0.790±0.010) V. A low electrochemical impedance, high corrosion rate, and typical active-passive transition in anodic polarization curves were observed and related to the sulfate concentration. In the presence of a high concentration of sulfate, the anodic polarization curves showed current peaks as a result of iron activation by sulfate ions. Sulfate ions of sufficiently high concentration in solutions degraded previously formed oxide layers on iron or transformed oxide layers in bicarbonate solutions. The transition of the open circuit state from passivity to active dissolution occurs at a lower sulfate concentration in a deaerated solution than in an aerated solution.

We synthesized Ni(OH)₂ nanowires/three-dimensional graphene composites using a hydrothermal method, and compared their properties with those of three-dimensional graphene, Ni(OH)₂ nanowires, reduced graphene oxide, and Ni(OH)₂ nanowires/reduced graphene oxide. The samples were characterized using Xray diffraction, scanning electron microscopy, thermogravimetric analysis, and N₂ physisorption measurements. The electrochemical performances were investigated using cyclic voltammetry and galvanostatic chargedischarge methods. The results showed that Ni(OH)₂ nanowires of width 20-30 nm were closely combined with graphene and crosslinked to one another to form a three-dimensional structure with a high specific surface area (136 m²·g^-1) and mesoporosity (pore diameter 20-50 nm). The mass fraction of Ni(OH)₂ nanowires in the Ni(OH)₂ nanowires/three-dimensional graphene composite was 88%. The maximum specific capacitance of the Ni(OH)₂ nanowires/three-dimensional graphene composite was 1664 F·g^-1 in 6 mol·L^-1 KOH electrolyte at 1 A·g^-1. The specific capacitance decreased by only 7% after 3000 cycles at 1 A·g^-1. A comparative study of the specific capacitances and cycling performances of Ni(OH)₂ nanowires, Ni(OH)₂ nanowires/reduced graphene oxide, three-dimensional graphene, reduced graphene oxide, and Ni(OH)₂ nanowires/three-dimensional graphene indicated that three-dimensional graphene with three-dimensional porosity and a larger specific surface area than conventional reduced graphene oxide enabled improved use of the active material and significantly enhanced the electrochemical performance of Ni(OH)₂ nanowires.

In the present work, we investigated the dynamics of charge collection and recombination in dyesensitized solar cells (DSSCs) spanning a large region of bias voltages using transient photoconductivity. The rate of charge collection was much faster than that of charge recombination at varied voltages, which was responsible for the nearly uniform charge collection efficiency. Based on this result, we simplified the diode characteristic model, which allowed us to directly fit the current-voltage (I-V) curve. A series of parameters related to the photo-to-electric processes in working DSSCs could be extracted from the proposed model, which could be used to evaluate the processes of charge generation, transport, and recombination in DSSCs, as well as the rectification of DSSC devices. We applied the fitting method to DSSCs with different 4-tert-butyl pyridine (TBP) concentrations of electrolyte. It was found that the rate of charge recombination significantly differed while that of charge collection was rather constant under different TBP concentrations, which was in od agreement with the results of I-V curve fitting. In addition, this research shows that the change of TBP concentration significantly affects the ideality factor (m) of DSSC devices.

The effects of temperature on the microstructure and physicochemical properties of alkali lignin (AL) in alkaline aqueous solutions were studied at 20-60 ℃. The relationships between temperature and the physicochemical properties of AL, such as the aggregation morphology, molecular surface charge and hydrophobicity, intrinsic viscosity, adsorption characteristics on gas-liquid and liquid- solid interfaces were investigated experimentally using particle charge detection, dynamic light scattering, zeta plus measurements, viscometry, surface tension and dynamic contact angle measurements, quartz crystal microbalance, ultravioletvisible and fluorescence spectroscopies. As the temperature increases, the molecular surface charge density, the intrinsic viscosity, and surface tension of the AL solution decrease significantly. In contrast, the molecular hydrophobicity, intermolecular and intramolecular aggregations, and the amount of AL adsorbed onto liquid-solid interface increase. The AL molecular state changes from extended to compact with increasing temperature. Furthermore, when the temperature increases, the absolute value of the zeta potential first decreases, then increases, and then decreases again. Analysis suggests that the increase in temperature not only reduces the ionization degree of the weak acidic groups in AL, but also weakens the hydrogen bonds between ALmolecules and water molecules. These two factors lead directly to changes in the AL microstructure and physicochemical properties. Based on the results of this study, a mechanism for the microstructural changes in AL with changing temperature was proposed. It was concluded that water would transform from a od solvent to a poor solvent with decreasing temperature. Although AL is often viewed as an anionic surfactant, the regular changes in its physicochemical properties with temperature are more like those of a nonionic surfactant.

Cu/SiO₂ catalysts for the hydrogenation of methyl acetate (MA) to ethanol were prepared using the urea hydrolysis method. The catalysts were characterized using N₂-physisorption, X-ray diffraction (XRD), temperature-programmed reduction (TPR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The effects of the copper loading and reduction temperature on the catalyst structure and catalytic performance were investigated. Experimental studies of the influence of the copper loading showed that a 20% (mass fraction, w) Cu/SiO₂ catalyst had uniformly dispersed copper particles and a large number of active centers, and therefore gave the best hydrogenation performances among the three catalysts with the copper loadings of 10%, 20%, and 30%, respectively. Then 20% (w) Cu/SiO₂ was reduced at different temperatures (270, 350, and 450 ℃). The results showed that 20% (w) Cu/SiO₂ reduced at 350 ℃ had the best catalytic activity. This was attributed to the homogeneous distribution of copper nanoparticles, and appropriate Cu⁰/(Cu⁰+Cu⁺) molar ratio, which achieved simultaneous dissociation of hydrogen and MA activation. Under the optimum reaction conditions, the MA conversion and ethanol selectivity reached 97.8% and 64.9% (theoretical maximum value: 66.6%), respectively.

We used skeletal Co as the core to prepare a skeletal Co@HZSM-5 core-shell catalyst by growing an HZSM-5 membrane on skeletal Co via hydrothermal synthesis. The physicochemical properties of the catalyst were determined using elemental analysis, N₂ physisorption, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and NH₃ desorption. In gas-phase Fischer-Tropsch synthesis (FTS), the skeletal Co@HZSM-5 core-shell catalyst was more efficient than a physically mixed skeletal Co-HZSM-5 catalyst in cracking long-chain hydrocarbons, giving higher selectivity for C₅-C₁₁ gasoline products. The thickness of the zeolite shell on the skeletal Co@HZSM-5 core-shell catalyst was easily tuned by adjusting the hydrothermal time. At a suitable zeolite shell thickness, the long-chain hydrocarbons were cracked completely, with high FTS activity, leading to high selectivity for the gasoline fraction. Increasing the reaction temperature resulted in higher FTS and cracking activities, but the product distribution shifted to short-chain hydrocarbons. For the optimum skeletal Co@HZSM-5 core-shell catalyst, which was subjected to hydrothermal treatment for 4 d, selectivity for the gasoline fraction reached 79% at 250 ℃, which shows an excellent synergistic effect between the FTS active sites and the acidic sites on this catalyst.

A visible-light-active graphitic-like carbon nitride (g-C₃N₄)/BiVO₄ nanocomposite photocatalyst was synthesized using a facile ultrasonic dispersion method. The nanocomposite was characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) spectroscopy, photoluminescence (PL) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and photocurrent response measurements. The photocatalytic activity in the photoreduction of CO₂ under visible-light irradiation (λ>420 nm) was determined. The g-C₃N₄/BiVO₄ catalyst containing 40% (w) g-C₃N₄ showed the highest photocatalytic activity; it was almost twice that of g-C₃N₄ nanosheets and four times that of BiVO₄. The enhanced photocatalytic activity is attributed to the formation of heterostructures at the g-C₃N₄/BiVO₄ interface and appropriate alignment of the energy levels between them, which can facilitate separation of photogenerated electrons and holes.

CuO-CeO₂-SiO₂ and rare-earth-doped CuO-Ce_0.9M_0.1O₂-SiO₂ (M=La, Pr, Nd) catalysts for recycling Cl₂ from HCl oxidation were prepared by a template method, using activated carbon as a hard template. The catalyst structures were determined using X-ray diffraction (XRD), N₂ adsorption-desorption, transmission electron microscopy (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and H₂ temperatureprogrammed reduction (H₂-TPR). The catalytic performances were also investigated. The results showed that La, Pr, and Nd cations were incorporated into the CeO₂ lattice and formed nanosized solid solutions; this greatly reduced the catalyst grain sizes, leading to higher surface areas. In addition, the oxygen vacancy concentrations were significantly improved. The changes in the structures and surface properties of the solid solutions significantly affected the HCl catalytic oxidation performances. The order of the activities of various catalysts was CuO-Ce_0.9La_0.1O₂-SiO₂>CuO-Ce_0.9Nd_0.1O₂-SiO₂>CuO-Ce_0.9Pr_0.1O₂-SiO₂>CuO-CeO₂-SiO₂. The oxygen vacancy concentrations of the solid solutions were strongly related to their catalytic activities. However, the structures and performances of the Ce_0.9M_0.1O₂-SiO₂ catalysts showed that an increase in the number of oxygen vacancies resulted in decreased catalytic activities of the solid solutions. Kinetic studies showed that oxygen adsorption could be the rate-determining step for rare-earth-doped catalysts; a higher oxygen vacancy concentration in the solid solution led to a slower reaction rate when the volumetric flow ratio of O₂ to HCl was 1. For the CuOCe_0.9M_0.1O₂-SiO₂ catalysts, spillover of oxygen species in the solid solution into the highly dispersed CuO interfaces was enhanced, which increased the overall reaction rate and gave high activity.

Poly(lactic acid) (PLA) has attracted considerable interest as an environmentally friendly and biodegradable polymer. The properties of poly(L-lactic acid) (PLLA) at an air/water interface were studied based on the Langmuir-Blodgett (LB) film balance and atomic force microscopy (AFM). The surface pressure-area (π-A) isotherm indicated that the surface pressure of PLLA initially increased as the interfacial film was compressed; at π=9.0 mN·m^-1, a plateau was observed in the π-A isotherm, in which the area of the repeat unit was in the approximate range 0.11-0.17 nm². The AFM results showed that there is a clear structural transition in the PLLA film during the compression: (i) at the beginning of the plateau, a number of fibrils are present at the air/water interface and (ii) multilayer structures (at least bilayer, i.e., the underlying layer and top layer consisting of fibrils) is formed in the plateau region. In particular, when π=20.0 mN·m^-1, a thin film of PLLA of thickness about 6.0 nm was fabricated. Our findings suggest that the plateau in the PLLA π-A isotherm is closely related to a change in the film structure from monolayer to multilayer at the air/water interface. This is significantly different from the behavior of conventional amphiphiles, because the plateau in amphiphiles π-A isotherm is equivalent to a phase transition of monolayers derived from amphiphiles in a two-dimensional plane.

Xylans are important as potential renewable energy sources. In recent years, there has therefore been interest in improving their degradation efficiencies. β-Xylosidases are key enzymes for xylan degradation; these enzymes are classified, based on their hydrolysis mechanisms, as retaining or inverting enzymes. Although much research has been devoted to understanding retaining and inverting mechanisms, little is known about their differences in solution. We used molecular dynamics (MD) simulations with explicit solvent representation to study the dynamic behaviors of the active-sites of four typical β-xylosidases by analyzing the distances between two catalytic amino acids and the pK_a values of proton-donor amino acids. The results show that the distance between the catalytic amino acids with inverting enzymes is about 0.8-1.0 nm, which is greater than that for retaining enzymes, i.e., 0.5-0.6 nm. This is consistent with previous results based on the crystal structures of glycosidases. We found that the pK_a of the retaining proton donors are modulated by interactions with neighboring amino acids, enabling switching between low and high values. Such a pK_a switch is needed for the double-displacement mechanism of retaining enzymes. In contrast, inverting proton donors, modulated by interactions with neighboring glutamic acids, have only high pK_a values. This may be important in proton capture from the solvent by donors, and may facilitate the single-displacement mechanism of inverting enzymes. This study provides new insights into the hydrolysis mechanisms of β-xylosidases, and will therefore be useful in improving the efficiency and applications of β-xylosidases.

Polyimide (PI) aerogels, which are generally crosslinked using expensive chemical crosslinking agents, are novel porous materials with high strength, high heat resistance, high porosity, and low density. Graphene oxide ( ) is a functional nanofiller that has aroused wide interest in recent years. The reported PI/ composites have mostly been in the form of fibers and films. In this study, PI/ composite aerogels were obtained using chemically modified graphene oxide (m- ) as the crosslinking agent, instead of traditional ones such as 1,3,5-triaminophenoxybenzene (TAB), by reaction with 4,4'-oxydianiline (ODA) and 3,3',4,4'- biphenyltetracarboxylic dianhydride (BPDA). The chemical modification of was achieved by reacting with excess ODA using a hydrothermal method. The microstructures of the PI/m- aerogels were investigated using scanning electron microscopy (SEM). Nitrogen sorption tests, thermogravimetric analysis, and a hot-wire method were used to investigate the effects of m- on the pore properties, thermal stabilities, and thermal conductivities, respectively, of the resulting aerogels. The results show that the PI/m- aerogels are highly porous, thermally stable, and heat insulating. Compression tests showed that the PI aerogel prepared using 0.6% (mass fraction, w) m- instead of 1.8% (w) TAB as the crosslinking agent had a higher specific Young's modulus [Young's modulus/density (ρ)] and specific yield strength (yield strength/ρ), and less shrinkage.

Ultrafine Au nanowires (AuNWs) were synthesized in high yields by a one-step wet chemical method using oleylamine as the solvent, surfactant, and reductant. The obtained AuNWs were of high purity and had a high aspect ratio, with diameters of ~2 nm and lengths of tens of micrometers. AuNWs of diameter ~9 nm were also obtained in the presence of oleic acid, at an oleic acid:oleylamine volume ratio of 1:1. The formation of AuNWs was studied by changing the reaction temperature and the volume of oleylamine. It is proposed that the growth mechanism of the Au nanostructures involves strong aurophilic interactions from oleylamine-AuCl complexes; the reduced Au atoms agglomerate and attach to preformed particles, and the oleylamine molecular layer acts as a soft template, leading to one-dimensional growth of Au atoms into AuNWs.

La- and N-doped SiC nanowires were prepared using a vapor-phase doping method and chemical vapor deposition method, respectively. The morphologies, element analysis, and crystal structures of the products were characterized by field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), selected area electron diffraction (SAED), high-resolution transmission electron microscope (HRTEM), X-ray energy dispersive spectrum (EDS), and X-ray diffraction (XRD). The field emission properties of the nanowires doped with different elements were tested by field emission measurements, and the results show that the turn on field (E_to) and threshold field (E_thr) of La-doped SiC nanowires are 1.2 and 5.2 V·μm^-1, and those of N-doped SiC nanowires are 0.9 and 4.0 V·μm^-1, respectively, these values are clearly lower than those of 2.3 and 6.6 V·μm^-1 for undoped SiC nanowires. In addition, the density of states (DOS) and band structures of undoped, N-doped, and La-doped, SiC nanowires were also calculated using Castep of material studio on the basis of the first-principles. The results of the theoretical calculations suggest that the narrower gap may be attributed to the impurity energy level (La 5d or N 2p) generated near the Fermi level. Because of the narrower gap, electrons transfer from the valence band maximum (VBM) to conduction band minimum (CBM) need less energy, and this enhances the field emission property.

A hexa nal lyotropic liquid crystal (LLC) was constructed with nonionic surfactant Triton X-100 and mixed magnesium chloride/aluminum chloride aqueous solutions. Layered double hydroxide (LDH) nanosheets (L-LDHs) were prepared using the LLC as a microreactor. A nanohybrid material of L-LDHs intercalated with a model anionic drug, diclofenac sodium (DS; DS/L-LDHs) was synthesized using an ionexchange method. The drug-release profile of DS/L-LDH was investigated under moderate conditions, i.e., 37.0 ℃ and pH 7.2. The results were compared with those for common LDH flaky particles (S-LDHs) synthesized using a traditional solution coprecipitation method. The crystalline structures, specific surface areas, and morphologies of these LDHs and DS/LDHs nanohybrids were characterized using powder X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and N₂ adsorption-desorption. The results show that the L-LDH JEparticles are less thick, and have larger specific surface areas and higher DS-loading capacities than the S-LDH particles. Drug release by the DS/L-LDH nanohybrid was clearly lower than that by the DS/S-LDH nanohybrid. This indicates that the L-LDH nanosheets are more suitable for use as drug carriers than the S-LDHs. Drug release by the DS/L-LDH nanohybrid can be described using a pesudo-second-order kinetic model, and drug diffusion through the LDH particles is the rate-limiting step. LLC can be used as a template for morphologycontrolled synthesis of LDHs.

A series of intrinsic silicon thin films were prepared using radio- frequency plasma-enhanced chemical vapor deposition (RF-PECVD) at low temperature and low power density. We investigated the influence of silane concentration (C_S) on the structural, optical, and electronic properties, and passivation quality of the intrinsic silicon films, and the performances of hydrogenated nanocrystalline silicon/crystalline silicon (nc-Si:H/ c-Si) silicon heterojunction (SHJ) solar cells. The results show that with decreasing silane concentration, substantial changes in the crystalline volume fraction, hydrogen concentration, structure factor, optical bandgap, and photosensitivity of the film take place in the transition zone. The passivation quality of intrinsic silicon thin films is decided by the hydrogen content and bonding structure of the film. Films close to the transition zone show od compactness and photosensitivities, high hydrogen content, and low state densities, and contain abundant SiH bonds. The films provide excellent passivation for c-Si surfaces and significantly enhance the open-circuit voltages of nc-Si:H/c-Si SHJ solar cells. However, the passivation quality deteriorates seriously when the film is too thin. In this work, the optimum silane concentration was found to be 6% (molar fraction). By optimizing the film thickness of the passivation layers with C_S=6%, we obtained an nc-Si:H/c-Si SHJ solar cell with an open-circuit voltage of 672 mV, short-circuit current density of 35.1 mA·cm^-2, fill factor of 0.73, and efficiency of 17.3%.