Non-contact atomic force microscope (NC-AFM) has become a powerful tool. It can provide the atomic structure and chemical bonding information at the atomic scale. Three kinds of tip- sample interactions are often concerned: including van der Waals interaction, electrostatic interaction, and chemical bonding interaction. In this work, the chemical bonding interaction between the tip and a Pb film is clearly demonstrated by NC-AFM based on a Q-plus force sensor. The tip-sample interaction energy versus the bias voltage was obtained and fitted by a parabolic function to find the effective local contact potential difference, which decreased with increasing tip- sample distance. Such a trend is caused by the wave function overlap. Thus, the decay length of the electron wave function was estimated. Oscillation of the decay length with film thickness was also observed, which can be attributed to the thickness-dependent quantum well states in the Pb islands.

Based on the eigenvalue analysis reduction method, a detailed mechanism of n-decane with 118 species and 527 reactions was simplified. A skeletal mechanism with 70 species and 327 reactions was thus obtained. The computational singular perturbation (CSP) reduction method, which is based on eigenvalue analysis, was subsequently used to simplify the skeletal mechanism, and a reduced mechanism with 38 species and 34 reaction steps was developed. Comparison between the reduced mechanism, skeletal mechanism, and detailed mechanism showed that the reduced and skeletal mechanisms could reproduce the characteristics of the detailed mechanism and give the combustion characteristics of n-decane. The development of these models represents a significant step toward coupling of chemical reaction kinetics with computational fluid dynamics, and is a od basis for improving computational efficiency.

In the present study, methyl decanoate (C₁₁H₂₂O₂) and n-heptane (nC₇H₁₆) were selected as a surrogate of biodiesel fuel. The molar ratio of the two constituents was determined to be 1:1, based on a comparison of the relative molecular weights, low heat values, and oxygen contents of the surrogate fuel and real biodiesel fuel. Furthermore, a chemical kinetic model including 691 species and 3226 elementary reactions of this biodiesel surrogate fuel was developed. The ignition delay times from experiments and calculations, under shock tube conditions, were compared; the computational results agree well with the experimental results. Comparisons of the in-cylinder pressure and main emissions under the engine conditions showed that the in-cylinder pressure calculated using this model agrees very well with the experimental result, and the trends in variations in the amounts of CO, unburned hydrocarbons, and NO_x emissions calculated using this model are also close to the experimental results. In addition, the lowtemperature reaction kinetics was analyzed in this study. The results show that the main products of methyl decanoate H- abstraction are MD2J and MDMJ. Besides the oxygen addition reaction, the main consumption paths of MD2J include reaction with C₇H₁₅O₂-3 (the product of the first oxygen addition of C₇H₁₅-1), decomposition to MP2D, and H-abstraction by O₂ forming MD2D. The main consumption paths of MDMJ are conversion to its isomers, MD2J and MD3J.

In the present work, Nd³⁺/Yb³⁺ co-doped TiO₂-La₂O₃-ZrO₂ (TLZ) glasses which were previously prepared by the aerodynamic levitation method were characterized by thermal differential analysis (DTA) and micro-hardness tests. The DTA technique was used to study the thermal stability of the characteristic temperatures, the glass transition temperature (T_g), the crystallization onset temperature (T_c), and the crystallization peak temperature (T_p), of the rare earth doped titanate glasses. The thermal kinetic DTA-analysis of the Nd³⁺/Yb³⁺ co-doped TLZ glasses was studied at heating rates of 5, 10, 15, 20 K·min^-1. The activation energy (E_a) and the pre-exponential factor (A) were obtained by the Kissinger and Friedman methods. In addition, the Vickers hardness was higher than 7.50 GPa and fracture toughness was higher than 1.20 MPa· m^1/2 for all the investigated TLZ glasses by the micro- hardness test. Furthermore, the upconversion luminescence property was investigated at 808 nm laser excitation, and three intense upconversion emission bands were observed. The excellent upconversion fluorescence, od thermal stability, and high mechanical strength suggested that this class of materials has potential for practical application in frequency upconversion devices.

ReaxFF molecular dynamics simulations of trinitrotoluene (TNT) pyrolysis show that use of the ReaxFF/lg potential function, which adds the London dispersion term, gives superior results in equilibrium density calculation of energetic materials. According to our calculations using limited time steps, the main products are NO₂, NO, H₂O, N₂, CO₂, CO, OH, and HONO, and H₂O, N₂, and CO₂ are the final products. We also used ReaxFF potential functions to simulate the same process to conduct a comparative analysis. The main and final products are consistent with those obtained using ReaxFF/lg, but the kinetics are different. Both ortho-NO₂ homolytic cleavage and C―NO₂→C―ONO rearrangement homolysis are thermodynamically favorable pathways in the early thermal decomposition of TNT. However, C―NO₂→C―ONO rearrangement homolysis is less favorable kinetically than C―NO₂ homolysis, since C―NO₂ is the weakest bond in TNT. Soon after their formation, NO₂ and NO participate in secondary reactions and eventually form N₂. Pyrolysis to form OH and other small molecules promotes the formation of H₂O. Aromatic ring fission does not take place until most of the attached groups have interacted or are removed, and increasing the temperature accelerates main-ring fission and further decomposition to form CO₂; this is the major reason for CO₂ distribution fluctuations under high-temperature conditions. When the TNT molecules in the unit cell are almost completely decomposed, the potential energy of the system is significantly attenuated. The maximum amount of carbon-containing clusters formed in the thermal decomposition is more dependent on density than on temperature. Moreover, the simulation results show that coagulation of carbonaceous intermediates occurs before the TNT decomposes completely. These studies show that the simulation of TNT pyrolysis using the ReaxFF/lg reactive force field can provide detailed kinetic and chemical information, which are helpful in understanding the detonation of energetic materials and assessing their security.

Clay minerals are used to remove organics and to remediate soils and groundwater contaminated with petroleum hydrocarbons. Cluster models of Si₆O₁₈H₁₂ and Al₆O₂₄H₃₀ for the tetrahedral (Si―O) and octahedral (Al―O) surfaces of kaolinite were set up to mimic kaolinite surfaces. The interactions of benzene molecule and the kaolinite cluster models were systematically studied at the MP2/6- 31G(d,p)//B3LYP/6-31G(d,p) level. The gas- state adsorption properties of benzene on the kaolinite surfaces, such as the optimized structures, structural parameters, adsorption energies, natural bond orbital charge distributions, vibration frequencies, electrostatic potential maps, electron density characteristics (the ρ and ▽²ρ values of secondary hydrogen-bonds), and electron density difference, were analyzed in this work. The optimized structures indicate that the adsorption of benzene molecule on the kaolinite surfaces may be caused by formation of secondary hydrogen-bonds. The results for the other properties further confirmed the existence of secondary hydrogen-bonds. Benzene molecule is more likely to be adsorbed on the Al―O surface than on the Si―O surface. The adsorption angle between the benzene ring plane and the kaolinite Al―O surface is about 90°.

As an unconventional gas, coalbed methane (CBM) is a desirable alternative energy source to conventional fossil fuels such as coal, oil, and natural gas. In this work, non-metallic atom X (X=H, O, N, S, P, Si, F, or Cl)- decorated Gr (graphene) (X-Gr) was used to represent the surface models of coal with structural heterogeneity. Using density functional theory, the adsorption of the CBM component Y (Y=CH₄, CO₂, H₂O) on X-Gr was systematically investigated. The results indicate that CH₄, CO₂, and H₂O are weakly bound to X-Gr, and the interactions between the adsorbate and the surface can be described as physisorption, which was identified through the density of states and electronic density difference analysis. Furthermore, CH₄ has very large adsorption energies to H- and Cl-decorated graphene. The dopants X, such as N, O, F, and Cl, are very od adsorbents for CO₂ and the influence of the dopants N and Cl cannot be ignored for the adsorption of H₂O. In general, the adsorption energies of H₂O on X-Gr are larger than those of CO₂, while CH₄ has the lowest adsorption energies, namely, the order of adsorption is H₂O> CO₂>CH₄. Consequently, the injection of H₂O or CO₂ into methane-rich coal seams strongly enhances the CBM recovery efficiency via competitive adsorption with CH₄ on the coal surface. The results provide a molecular-level insight into the interactions between CBM and X-Gr, and might offer useful information for recovery and purification of coalbed methane.

The effects of the first hydration shell and the bulk solvation effects on the proton-transfer processes of guanine-cytosine (GC) and adenine-thymine (AT) base pairs are studied based on density functional theory, using the B3LYP method and DZP++ basis set. The proton-transfer mechanisms of the GC and AT base pairs in bulk solvation are first single-proton transfer (SPT1) and stepwise double-proton transfer (DPT). When only the first hydration shell surrounded by five water molecules (GC ·5H₂O, AT· 5H₂O), or both the first hydration shell and bulk solvation effects through polarizable continuum model (PCM) (GC·5H₂O+PCM, AT·5H₂O+PCM) are considered, only the first single-proton-transfer mechanism (SPT1) is found. The proton- transfer activation energies of the GC and the AT base pairs show that the majority of the hydration effects come from the first hydration shell through hydrogen- bond interactions, therefore the first hydration shell greatly influences the base pair structures and proton-transfer mechanism.

The axial coordination behavior of the 5,10,15-tris(pentafluorophenyl)corrole manganese [(TPFC)Mn^Ⅲ] and 5,10,15-tris(pentafluorophenyl)corrole manganese(V)-oxo [(TPFC)Mn^VO] complexes with N-based ligands, such as imidazole, methylimidazole, isopropylimidazole, and pyridine, were investigated using density functional theory (DFT) at BP86 level. The results show these N-based ligands can form a stable axial coordination complex with (TPFC)Mn^Ⅲ in its quintet state. The coordination binding strength followed the order imidazole>4-methylimidazole>pyridine, which is in agreement with experimental results. The binding energy and the large distance between the Mn and N atom of the ligands indicates that (TPFC)Mn^VO cannot form an effective coordination bond in its singlet or triple state. Natural bond orbital (NBO) analysis indicates that the 3d orbitals of the Mn atom in (TPFC)Mn^VO are fully occupied, and there are no empty 3d orbitals to accept lone pair electrons from the ligands. However, there is a weak coordination interaction between the ligands and (TPFC)Mn^VO in its triplet state.

To investigate the effect of a tetrathiafulvalene (TTF) unit on the photovoltaic properties of the corresponding dye sensitizer, a TTF-carbazole-based sensitizer, Dye 2, was designed; it was based on the framework of Dye 1. The geometries, electronic structures, and optical properties of Dye 1 and Dye 2 before and after binding to (TiO₂)₉ clusters were investigated using density functional theory (DFT) and timedependent DFT. The surface morphologies of the dyes on TiO₂ (101) surfaces were simulated by periodic DFT calculations using the DMol³ program. The calculated results showed that the introduction of TTF units into dyes could help to inhibit dye aggregation on the TiO₂ surface; this is conducive to intramolecular charge- transfer transitions and significantly improves the light-harvesting ability. The calculated results demonstrate that the TTF unit is a very promising electron donor for improving the photovoltaic properties of organic dye sensitizers.

The electronic structures and optical properties of the nine poly(vinyldene fluoride) (PVDF) crystalline forms are calculated by the first-principles method based on density functional theory with inclusion of the Tkatchenko-Scheffler (TS) dispersion corrections. The nine crystalline forms of PVDF are insulators with band gap energies from6.05-7.34 eVat zero pressure and zero temperature. The calculated results of the band gap energy of the Ⅰ_p (β) and Ⅱ_ad crystalline forms are close to other experimental data or calculated results. The energy bands of PVDF crystals are dense and straight. The valence bands consist mainly of F-2s and F-2p states and the conduction bands are dominated by C-2p and H-1s states. In the 0-35 eV photon energy range, the optical properties, such as dielectric function, absorption, reflectivity and refractive index, primarily change in the deep ultraviolet region in our calculations. According to the spectra features (spectral range, peaks, etc.) of the optical properties, the nine crystalline forms of PVDF can be divided into four cate ries: {Ⅰ_p}, {Ⅱ_pu}, {Ⅱ_au, Ⅱ_ad, Ⅱ_pd, Ⅲ_pu}, {Ⅲ_au, Ⅲ_ad, Ⅲ_pd}. The crystalline forms in each cate ry have similar spectra features.

The structural stability and mechanical properties of α-Nb₅Si₃ alloyed with Ti, Cr, Al and B were investigated using first- principles methods based on density functional theory (DFT) by comparing the formation energy, valence electron concentrations, elastic constants, the shear modulus/bulk modulus ratio, and the Peierls stress. The results show that the structures of the α-Nb₅Si₃ alloys retain the stable D8₁ structure, in which the alloying elements Ti, Cr, Al and B prefer to occupy the Nb^4c, Nb^4c, Si^4a and Si^8h sites of α-Nb₅Si₃, respectively. The addition of Ti, Al and B increase the brittleness of D8₁ structured α-Nb₅Si₃, while Cr addition is beneficial to the toughness of α-Nb₅Si₃. Moreover, the influence of the alloying elements on the ductility/brittleness of α-Nb₅Si₃ was investigated based on analysis of the electronic structure, density of states and Mulliken population. The increased brittleness of α-Nb₅Si₃ by the addition of Ti, Al and B can be attributed to enhanced orientation of the covalent bonds, whereas Cr addition weakens the number and strength of covalent bonds and more anti-bonding states are occupied, thus improving the toughness.

We designed a series of models of reduced graphene oxide sheets (rGNOs) with different oxidation degrees and then studied the interactions between oxidation defects on rGNOs and nickel hydroxide (Ni(OH)₂) using density functional theory (DFT). The adsorption energy between the oxygen-containing groups on rGNOs and Ni(OH)₂ is dependent on the oxidation degree of rGNOs. The variations of atomic distances and charge distribution of the oxide-defected graphene after absorbing Ni(OH)₂ suggested that the oxygen-containing groups on rGNOs improve the characteristics of Ni(OH)₂ as a pseudocapacitor. These theoretical results agree well with available experimental observations and give an explanation for some experimental results. We also introduce a simple potentiostatic electrodeposition method, with which Ni(OH)₂ nanoparticles about 5 nm in diameter were effectively dispersed on the substrate via induction of oxidation defects on rGNOs. In the fabrication of Ni(OH)₂/rGNOs, electrochemical reduction of graphene oxide is the key process. The stronger adsorption results in Ni(OH)₂/rGNOs have higher rate pseudocapacitance (1591 F·g^-1 at 5 mV·s^-1) compared with that of Ni(OH)₂ on bare nickel (656 F·g^-1 at 5 mV·s^-1). The variations of the geometries and charge distributions of the rGNOs after absorbing Ni(OH)₂ lead to the lower equivalent series resistance and better frequency response of Ni(OH)₂/rGNOs than Ni(OH)₂/Ni. The high capacitance of Ni(OH)₂/rGNOs indicates that Ni(OH)₂/rGNOs have the potential of being used as the electrode material of pseudocapacitors.

A Si/SiOC/graphite composite structure with high efficiency and long-term cycling stability was synthesized using a cost- effective method. In this structure, a SiOC network with od chemical stability acts as a skeleton to support and segregate Si nanostructures. The graphite incorporated in the Si/SiOC composite is used as a conductive material to enhance the electrical conductivity. Such Si/SiOC/graphite composite anodes show excellent cycling stability, with a specific capacity of ~637.3 mAh·g^-1 and ~86% capacity retention over 100 cycles at a rate of 0.3C. The design of this new structure has the potential to provide a basis for the development of other functional composite materials.

The benzenethiolate-based solutions (RSMgCl)_n-AlCl₃/tetrahydrofuran (THF) (R=4-methylbenzene, 4-isopropylbenzene, 4-methoxybenzene; n=1, 1.5, 2, respectively) were obtained by the simple reaction of benzenethiol compounds with the Grignard reagent C₂H₅MgCl/THF and AlCl₃ in THF, and the electrochemical performance as the rechargeable magnesium battery electrolytes are reported. First, 4-methyl-benzenethiolate magnesium chloride (MBMC)/THF, 4- isopropylbenzenethiolate magnesium chloride (IPBMC)/THF, and 4- methoxybenzenethiolate magnesium chloride (MOBMC)/THF solutions (termed as RSMgCl/THF) were synthesized by the reaction of 4-methylbenzenethiol, 4- isopropylbenzenethiol, and 4- methoxybenzenethiol compounds, respectively, with C₂H₅MgCl/THF via a hydrogen metal-radical exchange with rapid evolution of ethane gas. Furthermore, (RSMgCl)_n-AlCl₃/THF solutions were obtained by the reaction of RSMgCl/THF with AlCl₃/THF at different molar ratios of RSMgCl:AlCl₃. The benzenethiolate-based solutions as electrolytes for rechargeable magnesium batteries were characterized in term of anodic stability and reversibility of magnesium deposition-dissolution using cyclic voltammetry and galvanostatic charge/discharge techniques. Furthermore, the compatibility of the solutions with Mo₆S₈ cathode material was verified using coin cells with a Mo₆S₈ cathode, Mg anode, and benzenethiolate-based electrolyte. It is concluded that both the substituents on benzenethiol and the ratio of RSMgCl:AlCl₃ have an effect on the electrochemical performance. 0.5 mol·L^-1 (IPBMC)_1.5-AlCl₃/ THF shows the best electrochemical performance with 2.4 V (vs Mg/Mg²⁺ ) anodic stability, a low voltage for magnesium deposition-dissolution, a high cycling reversibility, and od compatibility with the Mo₆S₈ cathode. Moreover, the air insensitive character and easy preparation make it a promising candidate for rechargeable battery electrolytes.

Pyrolyzed carbon supported ferrum polypyrrole (Fe-N/C) catalysts were synthesized with and without the dopant p-toluenesulfonic acid (TsOH) through a solvent-grinding method followed by heattreatment at the desire temperature. Both the catalysts were characterized using electrochemical techniques, such as cyclic voltammetry (CV), as well as the rotating disk electrode (RDE) technique. It was found that the catalysts doped with TsOH showed significantly better oxygen reduction reaction (ORR) activity than the undoped catalysts. The average electron transfer numbers for the catalyzed ORR were 3.899 and 3.098 for the TsOH-doped and undoped catalysts, respectively. Thermal treatment was found to be a necessary step for catalyst activity improvement. The catalyst pyrolyzed at 600 ℃ showed the best ORR activity: the onset potential and the potential at the current density of -1.5 mA·cm^-2 for the TsOHdoped catalyst were 30 and 170 mV more positive than those for the un-pyrolyzed TsOH-doped catalyst, respectively. To clarify the effects of TsOH doping and pyrolyzation, scanning electron microscopy (SEM), X- ray diffraction (XRD), and X- ray photoelectron spectroscopy (XPS) were used to analyze the morphology, structure, and composition of the catalysts. The XPS results suggest that the pyrrolic-N groups are the most active sites and sulfur species are structurally bound to carbon in the form of C―S_n―C and oxidized ―SO_n― bonds, which is an additional beneficial factor for the ORR.

Au and AuPd arrays were deposited onto an indium tin oxide (ITO) surface by the electrochemical wet stamping method. Agarose stamp with microstructures and solution was used to electrodeposit and generate patterns of a certain thickness. Field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray analysis (EDX), and atomic force microscopy (AFM) were employed to characterize the morphology and components on the surface. Tip generation-substrate collection (TG-SC) mode and redox-competition (RC) mode of scanning electrochemical microscopy (SECM) combined with cyclic voltammetry were used to explore the electrocatalytic activity of the alloy arrays. In the study of the electrocatalysis, AuPd exhibited higher activity for the reduction of H₂O₂ than pure Au, but lower activity for that of ferrocenemethanol oxide (FcMeOH⁺).

Cermet of Ni-YSZ (yttrium-stabilized zirconia) is commonly used as the anode material of solid oxide fuel cells (SOFCs) and the properties of the NiO-YSZ slurry has a significant effect on the performance of SOFCs prepared by wet processes. The stability of the NiO-YSZ slurry was investigated through zeta potential analysis. The effects of six dispersants on the surface zeta potentials of NiO and YSZ were examined. It was found that the zeta potential of NiO was opposite to that of YSZ when the anionic or amphoteric dispersant existed. When the cationic dispersant poly(diallyldimethylammonium chloride) (PDAC) was used, the zeta potentials for both NiO and YSZ were positive and they could be simultaneously suspended in water. By adding graphite, which is used as the pore former when fabricating the SOFC anode, into the NiO-YSZ suspension and using polyvinylpyrrolidone (PVP) as the dispersant of graphite, a stable NiO-YSZgraphite aqueous slurry was successfully prepared. The slurry was used to fabricate anode supports for SOFCs with the slip-casting technique. A typical single anode-supported SOFC showed a maximum power density of 509 mW·cm^-2 at 800℃. The microstructure of the SOFC with the anode support was examined by scanning electron microscope (SEM) analysis and it was found that the electrolyte and anode bonded well and the pores were homogenously distributed in the anode.

Nanocapsules containing polyaniline homodispersed in n-octadecane (n-Oct) were synthesized by free radical emulsion polymerization and in situ polymerization using poly(methyl methacrylate-co- allyl methacrylate) (P(MMA-co-AMA)) as a shell, in which polyaniline was used as the nucleating agent. Furthermore, the surface morphologies, crystallization properties, thermal stabilities, and crystallization process of nanoencapsulated phase change materials (NanoPCMs) were investigated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TG), and wide-angle X-ray diffraction (WAXD), respectively. The results showed that the addition of aniline as a monomer and polyaniline generated by in situ polymerization had little effect on the morphologies, particle sizes, encapsulation efficiencies, and crystallization process, but the heat resistance properties slightly decreased. Addition of 1.5 g of aniline effectively improved the supercooling crystallization behavior of the nanocapsule.

The development of synthetic vectors based on low-molecular-weight polyethylenimine (PEI) and the construction of negatively charged vectors with high nucleic acid encapsulation are two of the current research trends in gene delivery. In the present study, we developed a stable and negatively charged lipopolyplex based on oleic acid and a low-molecular-weight PEI (2 kDa); it was formed by simultaneously mixing oleic acid micelles and a polyplex produced from PEI (2 kDa) and oli dsDNA. This lipopolyplex is stable in serum, and because of the low molecular weight of the PEI, the lipopolyplex exhibits very low toxicity. The encapsulation efficiencies of nucleic acids by traditional anionic vectors are low, but very high (more than 80%) by this lipopolyplex. Suitable surface modification with 1,2-distearoryl-sn-glycero-3-phosphoethanolamine-N-methoxy(polyethyleneglycol-2000) ammonium salt enabled the lipopolyplex to bind to cells, and a high cellular uptake efficiency (ca 90%) was observed in vitro.

The effect of a Ce promoter on the catalytic properties of V/SiO₂ was investigated for the oxidative dehydrogenation of ethylbenzene (EB) to styrene (ST) with CO₂ (CO₂-ODEB). The catalysts were characterized by nitrogen adsorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H₂ temperature-programmed reduction (H₂-TPR), CO₂ temperature-programmed desorption (CO₂-TPD), and thermogravimetric analyses (TGA). It was found that incorporation of Ce into V/SiO₂ increased the dispersion of active V species, enhanced the redox properties of the system, and inhibited deep V reduction of V⁵⁺ to V³⁺ . The Ce promoter also improves the basicity of V/SiO₂ and CO₂ adsorption on the catalyst, and suppresses coke formation. The addition of a Ce promoter greatly improves the catalytic activity and stability of V/SiO₂ towards CO₂-ODEB. The ST yield and selectivity reach 55.6% and 98.5%, respectively, for CO₂-ODEB over the most efficient catalyst, V(0.8)Ce(0.25)/SiO₂, at 550℃, and a CO₂/EB molar ratio of 20. Moreover, after reaction for 12 h, the V(0.8)Ce(0.25)/SiO₂ still shows stable catalytic activity. The ST yield in CO₂ is higher than that in an inert N₂ atmosphere, showing the significant promoting effect of CO₂ on EB dehydrogenation; this is because CO₂ is a soft oxidant and can effectively keep/regain the high valence of V for high activity with CO₂-ODEB.

In this study, a continuous online in situ attenuated total reflection Fourier- transform infrared (ATR-FTIR) spectroscopic technique was used to monitor the behavior of butyl xanthate adsorbed on CuO nanoparticle surfaces. A red-shift phenomenon, i.e., the absorption peak at 1200 cm^-1 shifted to 1193 cm^-1, was observed in the FTIR spectra. However, there was no obvious change in the peak intensity after desorption using ultrapure deionized water, indicating that butyl xanthate was chemisorbed on the CuO surface. We determined the order of the spectral intensity changes in the adsorption process using twodimensional (2D) IR spectroscopy. The 2D asynchronous spectra showed that the spectral intensity of the characteristic peak at 1265 cm^-1 changed first. This may be attributable to the combined peaks of dixanthogen and xanthate molecular aggregates at the surfaces. The adsorption kinetics was studied by monitoring the intensity changes of the xanthate characteristic peak at 1200 cm^-1. The adsorption kinetic data showed that the maximum chemisorption capacity of CuO for butyl xanthate was 529 mg·g^-1, and the adsorption kinetics can be described by a pseudo-second-order reaction model.

The permeability coefficient is a fundamental parameter for devices exploiting the controlled drugrelease behavior of films composed of chitosan and sodium cellulose sulfate (NaCS). Here, the transport of two model drugs with different solubilities, i.e., paracetamol and 5-aminosalicylic acid (5-ASA), was studied. The results showed that the permeability of the chitosan/NaCS film was closely related to the swelling properties. In addition, both the permeability and swelling properties of the chitosan/NaCS film were significantly influenced by the mass ratio of chitosan to NaCS, the molecular weights (M_w) of chitosan and NaCS, and the pH value. The permeability of paracetamol across the film was also investigated in simulated gastrointestinal solutions in in vitro tests. The results showed that the films have gastro-, intestine-, and colon-targeting drugrelease properties when they are exposed to simulated gastrointestinal fluids in sequence.

The abnormal expression of cyclin-dependent kinase 1 (CDK1) leads to stagnation of the G2 phase and a variety of tumors. Therefore, CDK1 has been reported recently as an ideal cell cycle target for cancer drug discovery. In this paper, we use the cell division control protein 2 homolog as a template to homologically model the protein of CDK1 that is subsequently docked with the inhibitors of indirubin analogues. Three molecular alignment methods were used, and the corresponding three- dimensional quantitative structure-activity relationship (3D-QSAR) models were built using the comparative molecular field analysis (CoMFA) protocol in Sybyl 7.1 and the 3D-QSAR protocol (abbreviated for DS) in Discovery Studio 3.0. It was found that the molecular alignment method combining molecular docking with public template is most suitable for building the 3D-QSARmodels, and shows the best calculated results (CoMFA: q²=0.681, r²=0.909, and r_pred.²=0.836; DS: q²= 0.579, r²=0.971, and r_pred.²=0.795, where q² denotes the cross-validated correlation coefficient and r² denotes the non- cross- validated correlation coefficient). This paper may provide significant theoretical foundation for designing novel CDK1 inhibitors by carrying out structural modifications of indirubin analogues.

Co₃O₄ nanocubes that were exclusively terminated with {100} facets of edge size 10 nm were solvothermally fabricated in a mixed solution of ethanol and triethylamine. Analyses of the structural evolution of the intermediates at different intervals during the synthesis, together with an examination of the influences of the cobalt precursor and solvent on the product structure, showed that the formation of Co₃O₄ nanocubes followed a dissolution-recrystallization mechanism. After calcination at 200 ℃, the as-synthesized Co₃O₄ material retained a cubic morphology with the same edge size, but calcination at 400 ℃ resulted in the formation of spherical Co₃O₄ particles of diameter about 13 nm. The Co₃O₄ nanocubes exhibited inferior activity in room-temperature CO oxidation compared with Co₃O₄ nanoparticles ({111} facets), primarily as a result of the exposure of the less- reactive {100} facets, demonstrating the morphology effect of Co₃O₄ nanomaterials.