Two types of Surface Enhanced Raman Scattering (SERS) substrates were prepared by selfassembly of ld nanoparticle (GNP) monolayers film on either bare glass substrates (glass/GNP) or glass substrates with a 30 nm thick ld film (glass/Au/GNP). SERS spectra of dye molecules adsorbed on the two substrates were obtained by total internal reflection (TIR) of an excitation laser beam combined with collection of the air-side signal. The experimental results demonstrated that the signal enhancement factors of the two SERS substrates greatly depend on the polarization state of the excitation beam. In the case of the glass/GNP substrate, the signal enhancement factor obtained with the s-polarization TIR is two to five times as higher as that observed with the p-polarization TIR, indicating the formation of“hot spots”between adjacent particles in the GNP monolayer. With the glass/Au/GNP substrate, the SERS signal can be excited only by p-polarization TIR at a specific reflection angle, and the air-side SERS signal is almost 30 times that obtained with the glass/GNP substrate. The findings suggest that significant field enhancement is induced by the coupling between propagating surface plasmon resonance (SPR) and the localized SPR within the glass/Au/GNP substrate. Using a linear polarizer, the air-side SERS signal was verified to be non-polarized, containing s and p components of almost equal intensities. Further investigations revealed that the glass/Au/GNP substrate allows for directional emission of the SERS signal with the p-polarization state.

Homogeneous crystallization of supercooled water under electric field with strength ranging from 4.0 to 40.0 V·nm^-1 was investigated by using molecular simulation technique. The liquid-solid transition was successfully obtained based on ice component analysis using the CHILL al rithm. The analysis suggested that the produced crystalline was cubic ice dominant. The influence of the field strength on the structure and the growth rate of the ice was studied. The results revealed that the presence of an electric field drove the system to crystallize rapidly into dense and distorted cubic ice. The density of the crystals increased as a function of the field strength, from 0.98 to 1.08 g·cm^-3. The growth rate of the ice nucleus increased along with the field strength according to the characteristic time derived from the Avrami equation which ranged from 0.254 to 5.513 ns. This type of acceleration can be partially attributed to the enhancement of the rotational dynamics of the water molecules. Moreover, by monitoring the formation history of the cubic ice, we found that the defective ice acted as a transition state linking the liquid water and the cubic ice.

Many chemical substances will decompose in an autocatalytic manner, and such autocatalytic behavior can be identified through isothermal measurements, such as using differential scanning calorimetry (DSC) and microcalorimetry (C80). However, since it is difficult to predict the appropriate temperature for isothermal testing, it would be helpful to develop a simple and effective experimental method to distinguish autocatalytic decomposition. Based on the results of Roduit et al., a new technique for identifying autocatalysis is described herein, termed the“interruption and re-scanning”method. The decompositions of 2-ethylhexyl nitrate (EHN), 2,4-dinitrotoluene (2,4-DNT), dicumyl peroxide (DCP), and cumyl hydroperoxide (CHP) were assessed using both this new method and isothermal approach. Based on the results, the decompositions of EHN and DCP were found to proceed accord to the“nth order”law, whereas 2,4-DNT and CHP decomposed autocatalytically. We conclude that the interruption and rescanning method can be used to identify the characteristics of autocatalysis both quickly and effectively.

Using density functional theory with the B3LYP functional, the optimized geometrical structures of the M@t-Bu-calix[4]arene and (M@t-Bu-calix[4]arene)Li' (M=Li, Na, K) compounds were obtained. Five stable isomers were identified for each bi-alkali-metal-doped (M@t-Bu-calix[4]arene)Li' species. The first three lowlying isomers have considerable intramolecular interaction energies between alkali metal atoms and the t-Bucalix[4]arene molecule, indicating their stabilities. According to natural bond orbital analyses, the outside Li' atom is negatively charged in some (M@t-Bu-calix[4]arene)Li' structures, indicating the alkalide characteristics of these isomers. In addition, the nonlinear optical (NLO) properties of isolated and alkali-metal-doped t-Bu-calix [4]arene molecules were calculated using the CAM-B3LYP method. The results indicate that the single-doped effect of alkali metalMgreatly enhances the first hyperpolarizability (β₀) of the t-Bu-calix[4]arene molecule. In particular, when another Li atomis doped outside the M@t-Bu-calix[4]arene species, the resulting (M@t-Bucalix[4]arene)Li' compounds exhibit larger β₀ values. Obviously, the alkali-metal-doping effect plays a crucial role. The MLi'-4 conformation has the largest β₀ value (41827-114354 a.u.) among all the (M@t-Bu-calix[4]arene) Li' structural isomers, and it is found that the β₀ value of (M@t-Bu-calix[4]arene)Li' gradually increases with increasing atomic number of the alkali metal M. Therefore, alkali-metal doping is an effective approach to enhance the NLOresponse of the t-Bu-calix[4]arene molecule.

The adsorption of Au, Ag and Cu atoms on either one side or both sides of defected graphene were studied based on first-principles, using density functional theory (DFT), and the adsorption energies as well as the magnetic, charge transfer and electronic structures of the systems were calculated and analyzed. Compared with perfect graphene, the adsorption energies of Au, Ag, and Cu atoms on defected graphene were found to increase by more than 2 eV, demonstrating that the metal atoms are more easily absorbed at defect locations. Analysis of the electronic structures and charge density differences of these adsorption systems showed that chemisorption takes place between the Au, Ag, and Cu atoms and vacancy defects. The magnetic property results indicated that each of these three adsorption systems are magnetic. In the case of single-sided adsorption, the magnetic moments are approximately 1μ_B, while for double-sided adsorption, the magnetic moments are about 2μ_B.

Although trehalose is used as a protein stabilizer, the mechanism by which this stability is induced is not fully understood at present. In this study, we investigated the interactions between trehalose and all 20 common amino acids using all-atom molecular dynamics simulations. It is found that all the amino acids exhibit a preference for contact with water, especially the polar and charged amino acids. Conversely, only the hydrophobic amino acids were found to have a slight preference for contact with trehalose molecules. This tendency is most pronounced in the case of contact between trehalose and aromatic or hydrophobic side chains, whereas the backbones of each amino acids all show similar propensities for contact with water. Furthermore, hydrogen bonds between amino acids and trehalose were found to be significantly weaker than those between amino acids and water, although both trehalose and water can interact with the amino acids via hydrogen bonds. These findings are important with regard to the exploration of the molecular mechanism of protein stability induced by trehalose and the rational design of highly efficient protein stabilizers.

The geometric and electronic structures, energetics, and vibrational frequencies of different coordinate systems formed between 15 conformers of proline (Pro) and Cu, Cu⁺, and Cu²⁺ were investigated in detail, using the M06-2X and ωB97XDmethods with 6-311++G(2d, p) and TZVPbasis sets.Atotal of 20, 16, and 16 stable [Pro-Cu]^0/1+/2+ complexes were obtained at four levels. These structures demonstrated that 12 conformers of Pro exist in the [Pro-Cu] and [Pro-Cu]⁺ systems, while 11 conformers are present in the [Pro-Cu]²⁺ complexes. The most stable complexes are evidently not formed by the lowest energy conformer of Pro with Cu, Cu⁺, and Cu²⁺. In the CI3, CI4, CII7, and CII8 complexes, the carboxyl group hydrogen of Pro was found to transfer to the imino nitrogen to forma zwitterion. Both the relative energy difference and the deformation energy of Pro gradually increase along with the charge number of the Cu. The binding energies of the [Pro-Cu]^0/1+/2+ systems were determined to be in the ranges of -60.0 to -5.0, -340.0 to -170.0, and -1100.0 to -860.0 kJ· mol^-1, respectively. The stretching vibrational frequencies of the N―H and O―H bonds in Pro all exhibit a general red shift on complexation. Additionally, each systemshows charge transfer fromthe Pro to the Cu, even in the case of [Pro-Cu]²⁺, some complexes that have more than one negative charge.

Pt/cobalt-polypyrrole-carbon (Co-PPy-C)-supported catalysts were successfully prepared by pulse-microwave assisted chemical reduction. Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) techniques were used to characterize the catalyst microstructure and morphology. The electrocatalytic performance, kinetic characteristics of the oxygen reduction reaction (ORR), and durability of the catalysts were measured by cyclic voltammetry (CV) and linear sweep voltammetry (LSV) techniques. It was found that the particle size of Pt/Co-PPy-C was about 1.8 nm, which was smaller than that of commercial Pt/C (JM) catalysts (2.5 nm). The metal particles were well-dispersed on the carbon support. The electrochemical specific area (ECSA) of Pt/Co-PPy-C (75.1 m²· g^-1) was much higher than that of Pt/C (JM) (51.3 m²·g^-1). The results of XPS showed that most of the Pt in the catalysts was in the Pt(0) state, and XRD results showed that the form of Pt was mainly the facecentered cubic lattice. The Pt/Co-PPy-C catalyst had the same half-wave potential as Pt/C (JM) and showed higher ORR activity. The Pt/Co-PPy-C catalyst proceeded by an approximately four-electron pathway in acid solution. After 1000 cycles of CV, the ECSA attenuation rates of Pt/Co-PPy-C and Pt/C were 13.0% and 24.0% respectively, which means that the Pt/Co-PPy-C catalyst has higher durability. The high performance of Pt/Co-PPy-C makes it a promising catalyst for proton exchange membrane fuel cells.

Nitrogen-doped reduced graphene oxide materials (N-R ) derived from pyrolysis of graphene oxide ( )/polyaniline composites were used as a support for the immobilization of Pt nanoparticles. The morphologies and structures of N-R and Pt/N-R were comprehensively characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman spectroscopy. The electrocatalytic activities of the as-prepared catalysts for CO stripping and methanol oxidation were investigated by cyclic voltammetry and chronoamperometry. The results showed that was reduced to multilayer graphene by thermal annealing accompanied with successful incorporation of N atoms into R . Moreover, the presence of the doped N atoms enhanced the surface defects and electrical conductivity of the R materials. Pt nanoparticles on N-R were more evenly dispersed, had better CO tolerance, and had higher activity/stability for methanol oxidation than those on R without N doping.

Nitrogen-doped mesoporous carbons (NMCs) were synthesized by direct carbonization of zeolitic imidazolate framework-8 (ZIF-8) nanopolyhedrons. The surface morphology and structure were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and surface area and pore size analyzer. The electrochemical supercapacitive properties of the NMCs were also investigated. The results showed that the NMCs had a uniformmorphology, mesoporous nanostructure, and high surface area (2737m²·g^-1). On the other hand, based on the excellent surface wettability, pseudocapacitive behavior and electrolyte accessibility resulted fromN-doping and the mesoporous structure, the NMCs exhibited excellent electrochemical supercapacitive properties: a high specific capacitance (307 F·g^-1 in 1.0 mol·L^-1 H₂SO₄ solution, at 1 A·g^-1), od power characteristics, and satisfactory stability (the capacitance retained ratio was 96.9%after 5000 cycles even at a high current density of 10A·g^-1).

Tin has a theoretical specific capacity as high as 990 mAh·g^-1, and is thus a potential anode material for high-energy-density lithium-ion batteries. However, it suffers from a huge volume change during lithiation/delithiation process, leading to poor cycle performance. In this paper, core/shell structured FeSn₂-C composites were successfully synthesized by a simple high-energy ball milling technique with Sn, Fe, and graphite powder as raw materials. The FeSn₂-C composite was evaluated as an anode material for lithium-ion batteries. The influence of milling time and final phase composition on the microstructure and electrochemical performance of FeSn₂-C composites was systematically investigated. The failure mechanism of the FeSn₂-C electrode was also analyzed. The results reveal that long milling time can promote the mechanical alloying process of the FeSn₂ phase and reduce the particle size of the FeSn₂-C composite, which are beneficial for the increase of the specific capacity and the improvement of the cycle performance of the FeSn₂-C electrode. A high FeSn₂ phase content leads to a high specific capacity of the FeSn₂-C composites but poor cycling stability of the electrode. The optimized Sn₂₀Fe₁₀C₇₀ composite prepared by ball milling for 24 h (500 r ·min^-1) shows the best electrochemical performance with a capacity about 540 mAh·g^-1 for 100 cycles. The synthesized Sn₂₀Fe₁₀C₇₀ composite is a promising anode material for highenergy-density lithium-ion batteries.

The random poly(N-isopropylacrylamide-co-acrylic acid) copolymer (P(NIPAM-co-AA)) was synthesized and its stimuli-responsive self-assembly in pure aqueous solution was investigated. P(NIPAMco-AA) is a dual pH-and thermo-responsive hydrophilic random copolymer because it can self-assemble in pure aqueous solution in response to the stimuli of pH and temperature. The morphologies of P(NIPAM-co-AA) assemblies were imaged by transmission electron microscopy, and the radius (R_h) and radius distribution were determined by dynamic and static light scattering. The lower critical solution temperature (LCST) of P(NIPAM-co-AA) and the zeta potential change of the aqueous solution of P(NIPAM-co-AA) with respect to pH were measured. The driving force for pH-and thermo-responsive self-assembly of P(NIPAMco-AA) was deduced from the protonation degrees of two different chain units based on LCST and zeta potential data. The response of the special microstructure of the assemblies to environmental stimulation was confirmed by combining the above results with Fourier-transform infrared spectroscopy, which can provide information about the enriched chain units on the surface of assemblies. The experimental results showed that the P(NIAPM-co-AA) random copolymer can be easily synthesized and is both pH-and thermoresponsive. The stimuli-responsive self-assembly behavior of P(NIAPM-co-AA) in pure aqueous solution can potentially be applied to drug delivery.

We report the emulsification and thickening of crude oil using mixtures of cationic and anionic surfactants, which have high water content. The solubility of the mixed surfactants in simulated oil field water was improved by adjusting the surfactant molecular structure. The suitable concentration and mixing ratio ranges of various mixed systems were determined, and water in oil (W/O) lactescence with high water content was obtained. In addition, we studied the effects of temperature, pH value, ionic strength, and oil/water volume ratio on the emulsification and thickening processes. A series of mixed systems with od emulsification and thickening ability were determined and optimized. Notably, some of the systems increased the viscosity of the emulsion by up to 80 times. This has significance for the improvement of oil recovery.

MnO_x/CeO₂/SiO₂ catalysts were prepared by the adsorption phase reaction technique and were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy. HRTEM showed that MnO_x and CeO₂ particles were uniformly coated on the surface of SiO₂. The XRD spectra showed that the intensity of the Mn₃O₄ diffraction peaks gradually decreased and then completely disappeared with the increasment of the CeO₂ content, which indicated that CeO₂ reduced the crystallinity of MnO_x and improved the dispersibility of MnO_x. Raman spectroscopy indicated that Mn ions on the surface of catalysts could enter into the lattice of CeO₂, replace oxygen ions, and form oxygen vacancies. With the increasment of CeO₂ content, the density of oxygen vacancies initially increased and then decreased. We used the catalysts for selective catalytic reduction (SCR) of NO_x with NH₃. The catalytic activity initially increased and then decreased with the increasment of CeO₂ content, similar to the change in the density of oxygen vacancies. Thus, the catalytic activity of the MnO_x/CeO₂/SiO₂ catalysts increases with increasing the density of oxygen vacancies.

TiO₂-Al₂O₃ composite supports were prepared by in situ sol-gel and co-precipitation methods, and the supported nickel phosphide catalysts were prepared by incipient wetness impregnation and the in situ H₂ reduction method. The catalysts were characterized by X-ray diffraction (XRD), N₂ adsorption (BET), transmission electron microscopy (TEM), temperature-programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), and inductive couple plasma atomic emission spectrometry techniques (ICP-AES). The hydrodenitrogenation (HDN) activity of the supported nickel phosphide catalysts were evaluated on a continuousflow fixed-bed reactor using quinoline as the model molecule. The results showed that the composite support prepared by the in situ sol-gel method basically retained the original pore properties of γ-Al₂O₃ but with a larger surface area and decentralized pore size distribution, and TiO₂ was enriched on the tubular γ-Al₂O₃ surface. The composite support prepared by the co-precipitation method had a smaller surface area and a centralized pore size distribution, and TiO₂ was evenly dispersed on the massive γ-Al₂O₃ surface. The main active phases after reduction were Ni₂P and Ni₁₂P₅ for the catalyst supported on sol-gel prepared TiO₂-Al₂O₃, but only Ni₂P for the catalyst supported on co-precipitated TiO₂-Al₂O₃. Different TiO₂-Al₂O₃ preparation techniques and different Ti/Al atomic ratios had a great effect on the HDN activity of the catalysts. The catalyst supported on co-precipitated TiO₂-Al₂O₃ exhibited better reducibility and HDN activity than the catalyst supported on in situ sol-gel prepared TiO₂-Al₂O₃. The optimal HDN activity occurred for the catalyst supported on co-precipitated TiO₂-Al₂O₃ with an initial Ti/Al atomic ratio of 1:8. At a reaction temperature of 340 ℃, pressure of 3 MPa, hydrogen/oil volume ratio of 500, and liquid hourly space velocity of 3 h^-1, the HDN conversion of quinoline was 91.3%.

SnO₂/TiO₂ nanotube composite photocatalysts were synthesized by microwave-assisted hydrothermal and micro-emulsion methods. The photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy with energy-dispersive X-ray spectroscopy (TEM/EDX), and electrochemical techniques. Toluene was chosen as a model pollutant to evaluate the performance, deactivation, and regeneration behavior of the photocatalysts under ultraviolet (UV) and vacuum ultraviolet (VUV) irradiation. The results show that ternary heterojunctions of SnO₂/TiO₂ nanotube composite photocatalysts including anatase TiO₂ (A-TiO₂)/rutile TiO₂ (R-TiO₂), A-TiO₂/SnO₂, and R-TiO₂/SnO₂ were successfully created. They were able to separate photogenerated electron-hole pairs efficiently, and promote photocatalytic activity accordingly. SnO₂/TiO₂ showed the best photocatalytic performance. Under UV or VUV irradiation, the toluene degradation rate of SnO₂/TiO₂ was 100%, and the CO₂ formation rate (k₂) of SnO₂/TiO₂ was approximately 3 times higher than that of P25. Because of the low mineralization rate under UV irradiation, the refractory intermediates generated can occupy active photocatalytic sites on the photocatalyst surface, which hinders the photocatalytic oxidation rate. After 20 h of UV irradiation, the k₂ of SnO₂/TiO₂ decreased from 138.5 to 76.1 mg·m^-3·h^-1, implying that the photocatalysts can be deactivated quickly. VUV irradiation was employed to regenerate the deactivated SnO₂/SnO₂/TiO₂ nanotube composite photocatalysts were synthesized by microwave-assisted hydrothermal and micro-emulsion methods. The photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy with energy-dispersive X-ray spectroscopy (TEM/EDX), and electrochemical techniques. Toluene was chosen as a model pollutant to evaluate the performance, deactivation, and regeneration behavior of the photocatalysts under ultraviolet (UV) and vacuum ultraviolet (VUV) irradiation. The results show that ternary heterojunctions of SnO₂/TiO₂ nanotube composite photocatalysts including anatase TiO₂ (A-TiO₂)/rutile TiO₂ (R-TiO₂), A-TiO₂/SnO₂, and R-TiO₂/SnO₂ were successfully created. They were able to separate photogenerated electron-hole pairs efficiently, and promote photocatalytic activity accordingly. SnO₂/TiO₂ showed the best photocatalytic performance. Under UV or VUV irradiation, the toluene degradation rate of SnO₂/TiO₂ was 100%, and the CO₂ formation rate (k₂) of SnO₂/TiO₂ was approximately 3 times higher than that of P25. Because of the low mineralization rate under UV irradiation, the refractory intermediates generated can occupy active photocatalytic sites on the photocatalyst surface, which hinders the photocatalytic oxidation rate. After 20 h of UV irradiation, the k₂ of SnO₂/TiO₂ decreased from 138.5 to 76.1 mg·m^-3·h^-1, implying that the photocatalysts can be deactivated quickly. VUV irradiation was employed to regenerate the deactivated SnO₂/TiO₂ because reactive species such as ·OH, O₂^-·, O(¹D), O(³P), and O₃ can be generated. These play an important role in the oxidation of refractory intermediates on the photocatalyst surface, and k₂ increased to 143.6 mg·m^-3·h^-1 accordingly. Therefore, UV photodegradation combined with VUV regeneration could be a feasible photocatalytic process because of a synergistic effect between UV and VUV.

The performance of the Ni-Co bimetallic catalyst was significantly improved by a novel H₂ and CO₂ (HCD) pretreatment in the dry reforming of methane compared with traditional H₂ pretreatment. The effects of the HCD pretreatment operating conditions, such as pretreatment time, temperature, gas feeding ratio, and gas flow rate, on the catalytic performance of Ni-Co bimetallic catalyst were investigated. The optimal pretreatment time, temperature, gas feeding ratio (CH₄/CO₂), and gas flow rate were 0.5-1 h, 780-800 ℃, 0:10, and 175-200 mL·min^-1, respectively. Biogas was simulated with CH₄ and CO₂ in a volume ratio of 1 and without any other diluted gas. The catalyst was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetry (TG) coupled to differential scanning calorimetry (DSC). In a 511 h stability test under the optimized operating conditions, the catalyst pretreated with both H₂ and CO₂ exhibited excellent stability. The average conversions of CH₄ and CO₂, selectivities for H₂ and CO, and volume ratio of H₂/CO were 96%, 97%, 98%, 99%, and 0.98, respectively. The average carbon deposition rate over the Ni-Co bimetallic catalyst was only about 0.2 mg·g^-1·h^-1. The characterization results revealed that the sintering speed of the metal greatly decreased with testing time, and the metal particle will not greatly sinter with further testing time. The amount of deposited carbon on the catalyst gradually decreased and growth of filamentous carbon over the surface of the catalyst could be inhibited. The performance of the Ni-Co bimetallic catalyst was significantly improved by a novel H₂ and CO₂ (HCD) pretreatment in the dry reforming of methane compared with traditional H₂ pretreatment. The effects of the HCD pretreatment operating conditions, such as pretreatment time, temperature, gas feeding ratio, and gas flow rate, on the catalytic performance of Ni-Co bimetallic catalyst were investigated. The optimal pretreatment time, temperature, gas feeding ratio (CH₄/CO₂), and gas flow rate were 0.5-1 h, 780-800 ℃, 0:10, and 175-200 mL·min^-1, respectively. Biogas was simulated with CH₄ and CO₂ in a volume ratio of 1 and without any other diluted gas. The catalyst was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetry (TG) coupled to differential scanning calorimetry (DSC). In a 511 h stability test under the optimized operating conditions, the catalyst pretreated with both H₂ and CO₂ exhibited excellent stability. The average conversions of CH₄ and CO₂, selectivities for H₂ and CO, and volume ratio of H₂/CO were 96%, 97%, 98%, 99%, and 0.98, respectively. The average carbon deposition rate over the Ni-Co bimetallic catalyst was only about 0.2 mg·g^-1·h^-1. The characterization results revealed that the sintering speed of the metal greatly decreased with testing time, and the metal particle will not greatly sinter with further testing time. The amount of deposited carbon on the catalyst gradually decreased and growth of filamentous carbon over the surface of the catalyst could be inhibited. Thereby, great catalytic activity and stability could be obtained during the dry reforming of methane reaction.

A nano-scale monometallic Ru(0) catalyst was prepared by the precipitation method, and the effect of using ZnSO₄ and La₂O₃ as co-modifiers on the performance of the catalyst for selective hydrogenation of benzene to cyclohexene was investigated. The catalysts before and after hydrogenation were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), transmission electron microscopy (TEM), and N₂-physisorption. It was found that increasing the amount of alkaline La₂O₃ increased the amount of the ((Zn(OH)₂)₃(ZnSO₄)(H₂O)_x (x=1, 3) salt formed by the hydrolysis of ZnSO₄, which resulted in a gradual decrease of the activity of the Ru(0) catalyst and a gradual increase of the selectivity for cyclohexene. When the molar ratio of La₂O₃/Ru was 0.075, cyclohexene selectivity of 75.2% and cyclohexene yield of 58.4% at a benzene conversion of 77.6% were achieved in 25 min over the Ru(0) catalyst in the presence of ZnSO₄. Moreover, this catalytic system had od reusability. The mass transfer calculation results indicated that the liquid-solid diffusion constraints and pore diffusion limitations could all be ignored. This suggested that the high cyclohexene selectivity and cyclohexene yield could not be simply ascribed to physical effects, and were closely related to the catalyst structure and the catalytic system. Based on the experimental results, we suggest that the surface of the Ru(0) catalyst on which the (Zn(OH)₂)₃(ZnSO₄)(H₂O)_x (x= 1, 3) salt chemisorbed had two types of active sites for activating the benzene molecules: Ru⁰ and Zn²⁺. The ability of Zn²⁺ to activate benzene was much weaker than that of Ru⁰ owing to some electron transfer from Zn²⁺ to Ru⁰, which was confirmed by the XPS and AES results. Furthermore, Zn²⁺ could cover some of the Ru active sites because Ru and Zn²⁺ have similar atomic radii, which decreased the number of Ru⁰ active sites for activating H₂ molecules. As a result, the benzene activated on Zn²⁺ could only be hydrogenated to cyclohexene, and the activity of the Ru(0) catalyst decreased. A dual active site model is proposed, for the first time, to explain the reaction of benzene hydrogenation over the Ru-based catalyst, and Hückel molecular orbital theory was used to show the reasonableness of the model.

Two novel potential solution-processed blue fluorescent emitters composed of a core fluorenediphenylamine unit capped with either anthracene (FAn) or pyrene (FPy) were synthesized and characterized. They were both soluble in common organic solvents and solutions gave smooth films after spin coating. Their optical properties in solution and in the film were investigated by UV-visible and photoluminescence (PL) spectroscopy. The PL emission maximum of FAn and FPy in the film state were found to be 449 and 465 nm, respectively. The electrochemical properties of the as-prepared samples were studied by cyclic voltammetry. The estimated highest occupied molecular orbital (HOMO) energy levels were -5.37 and -5.36 eV for FAn and FPy, respectively. These results indicate that the introduction of diphenylamine effectively prevents plane stacking of the molecules in the solid state, which suppresses the formation of long-wavelength aggregates, and the high HOMO levels enhance the hole-injection ability of the compounds. The results of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) indicate that the two materials have excellent thermal stability with the glass transition temperature of FAn reaching 207 ℃ and the thermal decomposition temperature as high as 439 ℃. The od performance of the fluorescent emitters makes them promising candidates as solution-processed blue organic light-emitting diodes.

Bacterial chemoreceptors form homodimers that assemble into large clusters on cell membranes to respond to external signals. These clusters have been found to have two different types of patterns: one is composed of inverted pyramid like trimers-of-dimers observed in the X-ray crystal structures, and the other is formed by the zipper like overlap of tips of dimers, as revealed by low-resolution electron microscopy. The detailed molecular model of the zipper like assemblies has remained unknown until now. Using protein-protein docking method, we studied the interactions between serine chemoreceptor Tsr dimers in Escherichia coli. The basic complexes for the two types of clustering patterns were both found in the docking complexes. Molecular dynamics simulations confirmed that these complexes were stable to a certain extent. Protein-protein interface analysis indicated that electrostatic and hydrophobic interactions are the dominant driving forces for zipper like complex formation. Arg388, Phe373, and Ile377 are the key interfacial residues that stabilize the zipper like complexes. The molecular models for the zipper like complexes provide insight into the mechanisms of bacterial chemoreceptor assemblies on membranes and serve as a basis for further theoretical and simulation studies.

Three novel transitionmetal compounds [Cu_0.5L]_n (1), {[Ni(L)₂·(H₂O)₂]·(H₂O)₂}_n(2), and {[Co(L)₂·(H₂O)₂]· (H₂O)₂}_n (3), were hydrothermally synthesized with 4-(1H-1,2,4-triazol-1-ylmethyl) benzoic acid (HL) and characterized by infrared spectroscopy, elemental analyses, single-crystal X-ray diffraction, thermal analyses, UV-Vis spectroscopy, and fluorescence spectroscopy. Structural analyses reveal that compound 1 features a one-dimensional (1D) chain, while isomorphic 2 and 3 exhibit a three-dimensional (3D) network structure with interchain hydrogen-bonding. Antifungal activities tests reveal that 1 has the highest antifungal effect on the five fungi (Fusarium graminearum, Vasa mali, Macrophoma kawatsukai, Colletotrichum gloeosporioides, and Alternaria alternate) among the three compounds. Furthermore, DNA cleavage experiments indicate that compound 1 has more efficient DNA (pUC 18) cleavage activity than compounds 2 and 3. The binding properties of the three compounds with DNA were also investigated by absorption. The results show that the three compounds can intercalate into DNA, and the interaction of compound 1 is the strongest.

We report the synthesis of ld nanorods with a simple and efficient seedless method. By changing the experimental conditions, the longitudinal absorption peak of the ld nanorods can be shifted from the visible to the near-infrared region. Mercaptopolyethylene glycol (PEG-SH) was then used to substitute cetyltrimethyl ammoniumbromide (CTAB) to improve the biocompatibility of the ld nanorods. A strong inhibition of cancer cell growth was observed with the modified ld nanorods under near-infrared (NIR) light irradiation. Our results will be helpful for the potential applications of ld nanorods in clinical photo-thermal cancer therapy.

Iron silicides were grown on Si(110) and Si(111) substrates by the molecular beam epitaxy method at 650-920 ℃ and 920 ℃, respectively. Scanning tunneling microscopy observation showed that only nanowires (NWs) formed on Si(110), and the dimensions of the NWs increased with increasing growth temperature. The sizes of the NWs grown at 920 ℃ reached ~80 nm high, ~250 nm wide, and several μm long, and were much larger than NWs grown at 650 ℃, indicating that high temperature was favorable for NW growth. Electron backscatter diffraction characterization identified that the crystal structure of the NWs grown at 920 ℃ was β-FeSi₂ with a single orientation of β-FeSi₂(101)//Si(111)), β-FeSi₂[010]//Si[110]. Iron silicides grown on Si(111) at 920 ℃ formed three-dimensional (3D) islands and ultra-thin films. The 3D islands were identified as the Fe₂Si phase with hexa nal crystal structure and space group 164, and the cell constants at room temperature were a=0.405 nm and c=0.509 nm. The orientation relationship between the Fe₂Si phase and the Si(111) substrate was Fe₂Si(001)//Si(111), Fe₂Si[120]//Si[112].

We used the self-assembly method to formhigh purity (99%) semiconducting carbon nanotube (CNT) aligned arrays. Thin-film transistors (TFTs) were fabricated with asymmetric Pd and Sc electrodes. We studied the electronic transport characteristics and infrared photoelectronic properties of the TFTs with different channel lengths. The physical mechanism of carrier transport and the dissociation of photoexcited carries are also discussed. We found that the electronic and photoelectronic properties of the TFTs were dependent on the channel length and the average length of the CNTs. The on/off ratio of the device was the lowest when the channel length of the device (L) was less than the average length of the CNTs (L_CNT), and it increased with increasing L when L was larger than L_CNT. In addition, the short circuit current of the device also decreased. These results provide an effective reference for further infrared detector applications based on high-purity semiconducting carbon nanotube TFTs.

Ag nanoparticles (NPs) were uniformly immobilized in hierarchically porous monolithic silica using γ-(aminopropyl)triethoxysilane (APTES) as a modifier and ethanol as a reductant, where the silica monolith was pre-prepared via the sol-gel accompanied by phase separation. Ag NPs embedded in the hierarchically porous silica monoliths were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), mercury porosimetry, nitrogen adsorption/desorption analysis, and X-ray photoelectron spectroscopy (XPS). The mechanism of the modification by APTES, the reduction using ethanol, and pore structure changes of the silica monolith after immobilization of Ag NPs are discussed. The results show that APTES modifies the monolith by incorporating amino groups onto the surface of the meso-macroporous skeletons, and then amino groups react with silver ions to form a silver-amine complex. Ethanol used as an effective reductant is adopted to promote the reduction process of the silver-amine complex. Ag NPs with an average size of approximately 16 nm were homogeneously supported on both the macroporous skeletons and in the mesopores of the silica monolith with od dispersion. The embedding of Ag NPs did not spoil the macroporous skeleton of the monolithic silica, and the surface area decreased from 418 to 254 m² ·g^-1 after introducing Ag NPs into its macromesopores. It was also found that the loading amount of Ag NPs increased with repeated modification and reduction treatments.

Xu and Zhu published the paper entitled“Elimination of Bisphenol A from Water via Graphene Oxide Adsorption”. In section of 3.2 BPA adsorption kinetics, authors stated that “The pseudo-first- order model”and cited Blanchard et al. to be a reference. There is nothing about the pseudo- first- order model in the reference. It is a quotation error. The Lagergren rate equation presented in 1898, is a first order model. Basically, the rate of a reaction is defined as the change in concentration of a reactant or product per unit time. Concentrations of products do not appear in the rate law because the reaction rate is studied under conditions where the reverse reactions do not contribute to the overall rate. The reaction order and rate constant must be determined by experiments. In order to distinguish the kinetic equation based on the concentration of a solution from the adsorption capacity of solids, this Lagergren first order rate equation has been called a pseudo-first-order one. In addition, regression of pseudo-first-order kinetic model in Fig.1 would not be possible.

首先, 感谢Yuh-Shan Ho教授对我们在《物理化学学报》上发表的论文(Elimination of Bisphenol A from Water via Graphene Oxide Adsorption)的关注, 以及对文献引用提出的宝贵意见和建议.