Quasi-2-dimensional total amorphous and half-amorphous carbon structures are fabricated from single-layer or few-layer of graphene via high-energy electron beam irradiation. Sample structures before and after electron beam irradiation are recorded by high resolution imaging and coherent nano-area electron diffraction using transmission electron microscopy (TEM). The atomic pair distribution functions of the sample are obtained from electron diffraction patterns. In the quasi-2-dimensional amorphous carbon material, the carbon hexa nal ring structure is not the main structural feature anymore, and the low order nearest distances between carbon atoms are slightly different from that in perfect graphene. Although the sample shows a long-range disordered atomic arrangement, it still holds short-range order and even middle-range order extending to 0.5 nm, as many zigzag carbon chains remain after electron beam irradiation.

Organic light-emitting diodes (OLEDs) have attracted considerable attention during the last decade because of the potential advantages associated with their usage in full-color displays. Electroluminescent phosphorescent materials have also enjoyed similar levels of attention because of their excellent luminescent properties. The three primary colors, blue, green, and red, are essential for the practical application of phosphorescent complexes in flat-panel displays. Relative to the efficient green phosphorescent materials, red phosphorescent materials suffer many problems, including poor color purity, low efficiency, and low luminance, and the design of appropriate red colored materials therefore represents a significant challenge. Fused-heterocyclic compounds have been widely used in red phosphorescent iridium(III) complexes because of their high quantum efficiency, color adjustability, and balanced charge injection and migration. This review summarizes the development and application of fused-heterocyclic compounds in recent years in small molecule, dendrimer and polymeric red phosphorescent iridium(III) complexes. The influence of the molecular structures of iridium(III) complexes on the optical and electrical properties and device performances has also been described. Finally, a discussion of the prospect of developing fused-heterocyclic compounds in the red phosphorescent materials has also been provided.

The dynamic structures of 2-thiopyrimidone (2TPM) and 2-thiopyridone (2TP) in B-band absorptions were studied using the resonance Raman spectroscopy combined with quantum chemical calculations. In gas phase, 2-thiopyrimidine (2MPM, the thiol form) was more stable than 2TPM (the thione form) by ~15.1 kJ·mol^-1, whereas in water and acetonitrile 2TPM was more stable than 2MPM by 29.3 and 28.0 kJ·mol^-1, respectively. The transition barrier for the ground state proton transfer tautomerization reaction between 2TPM and 2MPM was ~130 kJ·mol^-1 in gas phase on the basis of the B3LYP/6-311++ G(d,p) level of theory calculations. The three absorption bands of 2-thiopyrimidone were respectively assigned as π_H→π_L^*, π_H→π_L+1^*, and π_H-1→π_L^* transitions. The vibrational assignments were carried out for the B-band resonance Raman spectra of 2TPM in water and acetonitrile solvents on the basis of the measurements from the Fourier transform (FT)-Raman and Fourier transform-infrared (FT-IR) spectra of 2TPM in solid and/or in solution phases and B3LYP/6-311++G(d,p) computations. The dynamic structures of 2TPM and 2TP were obtained by analysis of the resonance Raman intensity pattern. The differences in the dynamic structures of 2TPM and 2TP reflected differences in the structures of their ππ^*/πσ^* conical intersection points, and therefore could be used to provide insight into the photoinduced hydrogen-atom detachment-attachment mechanism.

The terahertz absorption and Raman scattering spectra of an alanine crystal in the range of 0.2-2.6 THz were obtained using terahertz time-domain spectroscopy and low-frequency Raman spectroscopy. The results indicated that there were four vibrational modes in this low-frequency region. Two modes were Raman active whereas the other two were both infrared and Raman active. A theoretical investigation on the periodic structure of alanine was performed using a self-consistent field crystal orbital method based on the B3LYP hybrid density functional. By comparing the experimental and theoretical results, irreducible representations were assigned to the corresponding peaks in the spectra. It was indicated that the vibrational modes in this low-frequency region were mainly torsion or rocking modes involving inter-molecular hydrogen bonds which have been described using schematic representations.

A new model has been developed to calculate the configurational entropy of mixing in liquid alloys involving consideration of chemical and topological short-range order. The entropy of mixing for an equiatomic random mixture was naturally reached by this model. The application of this model to both hypothetic and real binary liquid alloys demonstrated that the chemical short-range order always decreased the configurational entropy of mixing, whereas complicated behavior was found with the atomic size effect. The configurational entropy of mixing increased when the larger atoms entered into the matrix of the smaller atoms, whereas it decreased when the smaller atoms were mixed into the matrix of the larger atoms. The maximum of the configurational entropy of mixing was not located at the eutectic composition in these alloys.

A blue-green emitter of iridium(III) complex (ppy)₂Ir(pybi), has been synthesized (ppy= 2-phenyridine and pybi=2-(2-pyridyl)benzimdazole) and its structure was characterized by Fourier transform infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance (1H NMR), mass spectroscopy (MS), and elemental analysis. Its photophysical properties and energy-level structure were studied by UV-Vis absorption, excitation and emission spectroscopy, and cyclic voltammetry combining timedependent density functional theory (TD-DFT). The electrophosphorescent performance of (ppy)₂Ir(pybi) was characterized by using 4,4'-bis(9-carbazolyl)-1,1'-biphenyl (CBP) as host. The results indicated that the UV-Vis absorption bands were located at 250, 295, 346, and 442 nm, which were in od agreement with the TD-DFT simulation results. The blue-green phosphorescent emission was observed with peaks at 495, 518 nm in CH2Cl2 solution at room temperature. The highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) energy levels and optical gap were -6.11, -3.43, and 2.68 eV, respectively. Theoretical calculation revealed that the HOMO for (ppy)₂Ir(pybi) was mainly distributed on the ppy ligand and the iridium ion, whereas the LUMO was centered mainly on the pybi ligand. The device based on the system of (ppy)₂Ir(pybi) doped into CBP has an electroluminescence (EL) spectrum with a peak wavelength of 508 nm, a maximum luminance of 8451 cd·m^-2, and a maximum current efficiency of 17.6 cd·A^-1. These investigations will provide an important experimental basis for the application of (ppy)₂Ir(pybi) in the organic electroluminescent field.

In this paper, the liquid-solid equilibrium for the ternary systems composed of 1,2-propanediol, MCl (M=Na, K, Rb, Cs), and H₂O were studied at 298.15 and 308.15 K, with the mass fraction of 1,2- propanediol ranging from 0 to 0.9. The solubilities, densities, and refractive indices of the saturated systems, and the densities and refractive indices of the unsaturated solutions are reported herein. The solubilities were determined via a titration method using mercury nitrate as the titrant. Refractive index and density data were measured using an Anton Paar RXA170 refractometer and Anton Paar DMA4500 densimeter, respectively. The experimental values of the solubilities and densities of the saturated solutions decreased with increasing 1,2-propanediol concentration, whereas different trends of increase were observed for the refractive indices. The experimental density and refractive index data for the unsaturated solutions increased with increasing 1,2-propanediol to water ratios. Empirical equations have been provided for these properties as a function of concentration. On the basis of the standard deviations, we concluded that the empirical equations could be satisfactorily used to correlate the solubility, density, and refractive index data of the investigated systems. These values will enrich the thermodynamics data for alkali metals in mixed solvents, and lay a foundation for any subsequent work.

The heterogeneous uptake of limonene and limonene oxide (also known as 1,8-cineole) by a range of different aqueous sulfuric acid (H₂SO₄) solutions (30%-80% (w)) was investigated to develop an understanding of the reactivity of biogenic organic compounds in the atmosphere towards acidic aerosols. Experiments were performed using a rotating wetted-wall reactor coupled to a single photon ionization time-of-flight mass spectrometer. The heterogeneous uptake of the compounds into H₂SO₄ followed first-order kinetics and the corresponding steady-state uptake coefficients (γ) were calculated for the first time. Limonene oxide was found to be more reactive than limonene towards H₂SO₄. Reactive uptake was observed for limonene oxide in acidic solution containing greater than 30% (w). The steady-state uptake coefficients of limonene oxide in 30%-50% (w) H₂SO₄ solutions at room temperature ranged from (7.100± 0.023)×10^-5 to (8.150±0.162)×10^-3. Furthermore, the reactions of limonene oxide with sulfuric acid in bulk solution were investigated using gas chromatography-mass spectrometry (GC-MS) and electron spray ionization-mass spectroscopy (ESI-MS). Analysis of the products revealed the presence of monoterpenes, terpineols, terpin hydrates, and terpin hydrate diorganosulfate from the bulk solution reaction of limonene oxide with H₂SO₄. The formation of significantly more hydrophobic organic compounds with lower volatilities suggested that limonene oxide is a significant precursor in the formation of atmospheric secondary organic aerosols. A transformation mechanism has been proposed based on the products.

β-Cyclodextrin (β-CD) modified chitosan (CS), β-cyclodextrin-6-chitosan (CS-CD), was prepared and subsequently characterized by Fourier transform-infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) analysis. The CS-CD was used as an adsorbent for the adsorption of 2-chlorophenol (2-CP), 2,4-dichlorophenol (DCP), and 2,4,6-tuichlorophenol (TCP) from aqueous solutions. The Langmuir and Freundlich models were applied to describe the adsorption isotherms of the chlorophenols. The adsorption parameters have also been evaluated. The calculated maximum adsorption capacities for 2-CP, DCP, and TCP on CS-CD were 14.51, 50.68, and 74.29 mg·g^-1, respectively, indicating that the introduction of the β-CD moiety greatly increased the adsorption efficiency. Kinetic studies showed that the adsorptions were fast, in that all of the adsorption equilibria were reached within one hour, and that the adsorption processes followed a pseudosecond- order kinetic model. The thermodynamic parameters ΔG⁰, ΔH⁰, and ΔS⁰ were also calculated. The negative ΔG⁰ values indicated that all of the adsorption processes were spontaneous. A possible adsorption mechanism has been provided and discussed. The effects of electrolytes and pH values on adsorption revealed that hydrogen bonding between the chlorophenols and CS-CD dominated the adsorption process, which was further confirmed by FT-IR analysis. The adsorbent could be regenerated by washing with ethanol. Following six cycles of usage and regeneration, the mass and adsorption efficiency of the CS-CD remained at 90% and 82%, respectively. CS, however, showed greater mass loss and efficiency reduction following regeneration.

A dual-level direct dynamics method was employed to study the hydrogen abstraction reaction of C₂H₃ with CH₃F. The calculated potential barriers (ΔE^≠) of reaction channels R1, R2, and R3 are 43.2, 43.9, and 44.1 kJ·mol^-1, respectively, and the reaction energy is -38.2 kJ·mol^-1 at the QCISD(T)/6-311++ G(d, p)//B3LYP/6-311G(d, p) level. In addition, the rate constants of the reaction were evaluated by means of the conventional transition-state theory (TST) and canonical variational transition-state theory (CVT) with or without small curvature tunneling corrections (SCT) over a wide temperature range of 200-3000 K. The results indicate that the rate constants of the three hydrogen abstraction reaction channels exhibit a positive temperature dependence, in which the variational effect is negligible for all the channels, whereas the tunneling effect is considerable at lower temperatures. Moreover, the reaction R1 is the dominant channel. Reaction R2 competes kinetically with R1 as the temperature increases, whereas the contribution from R3 is small.

The formation mechanism of ethyl tertiary butyl ether (ETBE) from ethanol and isobutene catalyzed by HZSM-5 has been investigated using the ONIOM (B3LYP/6-31G(d,p):UFF) method. The calculation results of the reactants adsorbability reveal that the interaction between ethanol and the acidic sites on HZSM-5 leads to the formation of hydrogen bonds. The interaction between isobutene and Brönsted acidic sites leads to the formation of a π-complex. It is subsequently found that the mechanism of the ETBE formation from ethanol and isobutene catalyzed by HZSM-5 is a concerted reaction, and that the order of reactant adsorption onto HZSM-5 affected the reaction. The favorable pathway is based on the complex formed by the simultaneous adsorption of ethanol and isobutene, in which the H atom of the π-complex is transferred to the C atom of the C＝C in isobutene, and the O atom of the adsorbed ethanol is transferred to the other C atom of the C＝C to form the C－O bond. In this process, the proton of the acidic sites adds to the C＝C bond forming the C－H bond, and the H atom of the ethanol hydroxyl interacts with acidic sites, generating a new proton. The corresponding lowest energy barrier was 25.14 kJ·mol^-1.

To study the configuration, the metal-metal interactions and the influences of axial ligands L and L' on the Cr—Cr bond in metal string complexes Cr₃(dpa)₄LL' (L, L'=Cl, BF₄, CCPh), the structures of complexes Cr₃(dpa)₄Cl₂ (1), Cr₃(dpa)₄(BF₄)2 (2), Cr₃(dpa)₄Cl(BF₄) (3), Cr₃(dpa)₄(CCPh)2 (4) and Cr₃(dpa)₄Cl(CCPh) (5) were investigated by density functional theory UBP86 method. The conclusions can be drawn as follows: (1) The complex with longer average Cr—Cr distance tends to form a symmetrical configuration, while it tends to form a asymmetric configuration with shorter average Cr—Cr distance. The most stable spin states, quintet states, with the longest average Cr—Cr distance tend to form a symmetrical configuration, while septuplet states with shortest Cr—Cr distance tend to form asymmetrical one; (2) For quintet states of all complexes, there is only a 3-center-3-electron σ bond in Cr₃⁶⁺ chain. Furthermore, except the σ bond, there are weak π Cr—Cr interactions in complex 2 and 3. For septuplet states, there is a triple bond in the short Cr—Cr bond of complexes 1-3 and 5, while there is only a 3-center-3-electron σ bond in complex 4. Not only in symmetrical configuration but also in asymmetric configuration, there are σ delocalizations in Cr₃⁶⁺ chain, suggesting the asymmetrical metal string complexes are still the potential molecular wire species; (3) The interactions between axial ligand L and Cr atom mainly correspond to the n_L→4_sCr and n_L→3_dz²Cr delocalizations. In addition, for stronger σ donor CCPh^- ligand, there are σ_C—C→4_sCr delocalizations as well. The order of the bond strength of axial ligand L and Cr atom is 2＜3＜1＜5＜4. The strongest bonding between CCPh^- ligand and Cr atom weakens the Cr—Cr bond and lengthens the Cr—Cr distance. Therefore, every spin state of 4 tends to form a symmetrical configuration.

4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) fluorescent pH probes are fluorescent sensors and switchers based on photo-induced electron transfer (PET) mechanism. From experimental studies, different substituents on the amino nitrogen are known to result in variable photo sensitivities. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations are used to optimize the structures of six different BODIPY probe molecules with different substituted amines, and to study their exited states. In the ground state, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the probe molecules are located on the π and π^* orbitals of the BODIPY dye, and the lone pair electrons from the amino nitrogen form the HOMO-1 orbital. In the first exited state, for the probes with two substituent groups on the amino nitrogen, the HOMO-1→ LUMO transition has a smaller emission energy than that of the HOMO→LUMO transition in the BODIPY host, which may induce the PET effect and quench the fluorescence. After the geometry optimization of the exited states, irrespective of whether one or two groups are linked on the amino nitrogen, the orbital symmetry of the nitrogen atom changes from sp³→sp², and the lone pair electrons occupy the p orbital situated between the HOMO and LUMO of BODIPY, resulting in the PET effect. The calculated results are in od agreement with the experimental results.

A luminescent donor-π-bridge-acceptor-π-bridge-donor (D-π-A-π-D) type naphthalene-based derivative and its“CH”/N substituted derivatives have been designed and their electronic, optical, and charge transport properties were investigated using quantum chemical approaches. Our calculations have shown that changes in molecular structure lead to modifications in the electronic structure, resulting in a modulation of the electronic bandgap and hence of the optical properties. Remarkably, the calculated emission spectra can nearly cover the full UV-Vis spectrum (from 447.7 to 743.1 nm). Also, large Stokes shifts were observed, ranging from 106.1 to 222.4 nm, resulting from a more planar conformation of the excited state between the two adjacent units in the molecular backbone relative to the ground state. Calculated results also showed that the designed compounds could be used as hole transport materials in organic light-emitting diodes.

Density functional theory (DFT) calculations are used to investigate the effect of substituents on the Mn―O bond in A3-type oxo-manganese(V) corrole complexes. Results indicate that the Mn―O bonds in all the investigated oxo-manganese(V) corrole complexes are triply bonded by one σ and two π bonds. As the electron withdrawing ability of the substituents increases, the corrole skeleton contracts, resulting in a decrease in the Mn―O bond length, and the Mn―O Raman stretching vibration shifts to higher wavenumber. As the electrostatic potential of the substituents changes from positive to negative, the electrostatic interaction between oxygen and substituents changes from a negative-positive electrostatic attraction to a negative-negative electrostatic repulsion. Electron withdrawing substituents enhance oxygen reactivity of corrole Mn-oxo complexes by lowering the Mn―O bond dissociation energy.

The structural characteristics of the peptide segment of the P53-DNA binding domain (from residue 230 to 258) were studied using molecular dynamics simulations with different mutations, including R249S, R248W, and G245S. Four independent simulations, including the wild-type segment wtP53, onepoint mutation segment P53-R249S, two-point mutation segment P53-R249S/R248W, and three-point mutation segment P53-R249S/R248W/G245S, were performed using the GROMACS software package and GROMOS 43A1 force field. Each simulation was run for 500 ns. The results indicated that mutation R249S affected the formation of the secondary structure for some residues, but had little impact on the mode of the ternary structure and made the segment more stable than the wild-type segment. In contrast, the R249S/R248W mutation strengthened the effect of R249S on the segment and induced a significant change in the ternary structure, with the structure of the two-point mutation segment R249S/R248W existing as a double-turn motif and becoming more stable. Moreover, the G245S mutation had the opposite effect on the segment, decreasing or eliminating entirely the effects caused by the R249S/R248W mutation on the segment. This study provided important understanding of the molecular mechanism of tumorigenesis and the design of a new drug.

A semiclassical electronic radiation ion dynamics (SERID) simulation was used to study the photophysical deactivation of π-stacked adenine and thymine. A laser was only applied to the thymine molecule during the simulations. The results showed that an (A⁺T^-)^* type exciplex was formed between excited thymine and unexcited adenine as a consequence of charge transfer. When the intermolecular distance was less than 0.300 nm, the stacked system was recovered to electronic neutrality by charge recombination because of the orbital delocalization effect. When the torsion angle of the C4'－C5' bond of the adenine molecule reached its maximum, the exciplex decayed to its ground state via an avoided crossing. The deactivation channel of the exciplex was found to be dependent on the intermolecular distance and deformation of the adenine molecule. It was difficult for the adenine molecule to under strong twist required for deactivation because of the steric hindrance encountered by the C4' and C5' atoms. Consequently, the lifetime of the A-T exciplex was clearly longer than that of the T-T exciplex.

Molecular dynamics simulations were carried out to study the decomposition of CH₄ hydrate in the presence of poly(2-ethyl-2-oxazoline) (PEtO) at different concentrations, including 1.25% , 2.50%, and 6.06% (w, mass fraction). The simulation system was composed of a CH₄ hydrate crystal and PEtO, which contained a 2×2×2 supercell of CH₄ hydrate crystal and PEtO polymer. System configurations showed that hydrogen bonding networks between water molecules making up the main framework of the hydrate cages were distorted in the presence of the PEtO polymer. Final configurations in all of the systems were completely collapsed. Radial distribution functions of the oxygen atoms, mean square displacements, and diffusion coefficients of water molecules were applied to compare the effect of different PEtO concentrations on the CH₄ hydrate. Within a certain concentration range, higher concentrations led to a better inhibition effect. It was confirmed that PEtO is a type of prospective low dosage inhibitor with biodegradability. The decomposition mechanism involves the absorption of the PEtO polymer onto the surface of the hydrate crystal, with its active functional group (N ―C＝O) forming hydrogen bonds with water molecules in the hydrate and decomposing the hydrate surface. PEtO continued to decompose the surface layer of hydrate, resulting ultimately in the collapse of the hydrate cages.

The nucleation and growth of Na₂CO₃ particles in supercritical water were investigated using molecular dynamics simulation. The clustering process of Na₂CO₃ was studied for 1 ns at a series of state points, across temperature and pressure ranges of 700 to 1100 K and 23 to 30 MPa, respectively. The binding energy and radial distribution function analysis showed that the electrostatic interaction was the main factor affecting the whole Na₂CO₃ nucleation process. Under supercritical conditions, the electrostatic interaction of water molecules with Na⁺ and CO₃^2- ions rapidly decreased, allowing Na⁺ and CO₃^2- ions to readily collide with each other to form small Na₂CO₃ clusters. During the initial Na₂CO₃ nucleation process, all the single-ion collisions were complete within 50 ps and the ionic collision rates appeared to be of the order of 1030 cm^-3·s^-1. Furthermore, the effect of temperature was found to be more important than that of the pressure at the nucleation stage and a higher temperature led to an enhanced collision rate and the formation of more initial Na₂CO₃ particles. The further growth of the Na₂CO₃ particles was more dependent on the pressure.

Based on the density functional theory and the non-equilibrium Green?s function method, the electronic transport properties of zigzag-edged triangular graphene were studied systematically. The results revealed that the current-voltage (I-V) characteristics and rectifying effects were closely related to the geometric size and the type of atoms terminated at the edges of triangular graphene. In the case of Hand S- terminated edges, a small triangular graphene had a large current but with a small rectifying ratio. Although the current increased, the rectifying behavior was lowered when H atoms at the edges of the structure were replaced by O atoms. Deeper analysis demonstrated that such a rectification was caused by the asymmetry in the spatial distribution of the frontier orbitals and an asymmetric movement on the molecular-level in triangular graphene under positive and negative biases. It is of great significance that our investigations develop a thorough understanding of the basic physical properties of a triangular graphene.

CCSD(T) calculations with small-core relativistic effective core potentials for equilibrium bond lengths and harmonic frequencies are presented for uranium triatomic OUO²⁺, NUN, and NUO⁺ species. The inner shell electron correlation of the U atom has almost no effect on the properties of these species, and the spin-orbit coupling only has a small effect, except in the bending mode of NUN. Our results agree reasonably well with previous theoretical results and the available experimental data, which indicates that the single-reference CCSD(T) method can be employed to study these species. Compared with previous results, the CCSD(T) results agree best with density functional theory (DFT) calculations performed using the PBE0 functional. The present work provides new estimates which are useful for future experimental work and for choosing proper exchange-correlation functionals in DFT calculations for these species.

We proposed a periodic interaction model for the CuM₂Al-layered double hydroxides (CuM₂Al- LDHs), where M represents the different divalent metal ions (Mg²⁺, Ca²⁺, Zn²⁺, Cd²⁺, Ni²⁺, Co²⁺) that might partially replace the copper ion. Based on density functional theory, the geometry of CuM₂Al-LDHs was optimized using the CASTEP program. The stabilities of Cu-containing LDHs were investigated by analyzing the geometric parameters, electronic distribution, charge populations, hydrogen-bonding, and binding energies. The results showed that the electrostatic interactions between the host layer and the guest played a major role in the laminate thickness of the CuM₂Al-LDHs. M ions had only a minor effect on the central Al³⁺, whereas they had a major effect on the Cu²⁺. Furthermore, M ions with a uniform distribution of valence electrons had only a negligible impact. In addition, in the CuM₂Al-LDHs, where the valance electrons of the M ion were uniform, both the electrostatic interactions between the host layer and the guest and the level of hydrogen-bonding increased. In general, as the period number of the M ion increased, the distortion angle of the system also increased, and the absolute value of the binding energy and the chemical stability of the system decreased. The stability of the CuCo₂Al-LDHs was the lowest of all of those tested because of the nonuniform distribution of the Co²⁺ valence electrons. These results provide a comprehensive understanding of the rules required for the synthesis of Cu-containing LDHs.

Hydrogen storage behavior in a Li-decorated B₁₂N₁₂ cage is investigated using first-principles calculations based on density functional theory (DFT). In the optimized adsorption structure, three Li atoms are adsorbed above the N atom of the B₁₂N₁₂ cage (Top-N site). Each Li atom is adsorbed on the bridge site of B－N between the four- and six-membered rings. In addition, each Li atom in the B₁₂N₁₂ cage adsorbs three H₂ molecules, and two H₂ molecules are adsorbed outside the B₁₂N₁₂ cage, with an average H₂ adsorption energy of -0.14 eV. Inside the B₁₂N₁₂ cage, the adsorbed hydrogen remains in the molecular form. Our work shows that the maximum hydrogen storage capacity of Li-decorated B₁₂N₁₂ cage is 9.1% (w).

Large-scale synthesis of few-layer graphene nanosheets (GNSs) with high crystallinity and electrical conductivity (1680 S·m^-1) is achieved by an arc-discharge method. The GNSs exhibited od morphologies as observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). However, electrochemical testing showed that the performance of the graphene (GNS) electrodes in supercapacitors was poor. To increase the surface active sites for electrochemical reactions and promote the wettability by aqueous electrolyte of the GNSs, a nitric acid treatment was used to chemically modify their surface. The acid treatment introduced more oxygen/nitrogen-containing functional groups onto the GNS surface, and clearly enhanced the hydrophilicity. The nitric-acid-modified GNSs (H-GNSs) showed vastly better electrode performance, with a maximum specific capacitance of 65.5 F·g^-1 (about 30 times that of original GNSs) at a current density of 0.5 A·g^-1 in 2 mol·L^-1 KOH electrolyte. In addition, the H-GNS electrode showed od cycling stability and lifetime after running 2000 cycles. Therefore, H-GNSs may be an attractive candidate as electrode materials for supercapacitors.

Lithium ion capacitors (LICs) were fabricated using Li +-intercalated mesocarbon microbeads (LMCMBs) as the negative electrode and commercial activated carbon (AC) as the positive electrode. The phase structure of LMCMB electrodes was characterized by X-ray diffraction (XRD). LMCMB electrodes retain their original graphite crystal structure when the capacity induced by initial Li⁺ intercalation is less than 200 mAh·g^-1. The charge-discharge performances of positive and negative electrodes and LICs were studied using a three-electrode cell. Using an LMCMB electrode as an anode, a stable working potential is obtained at lower voltage than using other electrodes, and the potential range of the positive electrode is extended to a lower range. The electrochemical performance of LMCMB/AC capacitors, including capacitance, cycle life, and efficiency, is improved compared with that of an MCMB/AC capacitor. The efficiency increases from less than 95% to nearly 100%, and the capacity retention is improved from 74.8% to nearly 100% for 100 cycles in a voltage range of 2.0 to 3.8 V. The stable capacity of LMCMB/AC capacitors with cycling is directly correlated to less polarization of AC during the charge storage process, which is caused in turn by the LMCMB negative electrode. Gravimetric energy densities as high as 85.6 and 97.9 Wh·kg^-1 are obtained in voltage ranges of 2.0 to 3.8 V and 1.5 to 3.8 V, respectively.

The aim of this study was to resolve the poor bonding strength between carbon film and the conductive substrate in a carbon counter electrode. A carbon black-conductive carbon (Cb-CC) counter electrode was fabricated using a low-cost commercial conductive carbon paste (CC) as a binder and carbon black (Cb) as a catalyst. Film adhesion test results indicated that the introduction of the CC significantly improved the adhesion between Cb and the conductive substrate, as well as the conductivity and stability of the carbon counter electrode. The porous structure of the mixed CC and Cb carbon films was maintained as illustrated by scanning electron microscopy (SEM). Cyclic-voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements showed that the catalytic activity of CC-Cb was superior to that of CC. A dye-sensitized solar cell (DSSC) based on the CC-Cb counter electrode exhibited an excellent photoelectrical performance, reaching an energy conversion efficiency of 6.54%. The amount of CC in the carbon counter electrode was further optimized. Consequently, when the mass ratio of Cb:CC reached 23:77, the corresponding DSSC yielded the highest energy conversion efficiency recorded in this study at 6.81% . In addition, long term stability testing showed that the photovoltaic parameters of the DSSC based on the CC-Cb counter electrode remained similar to the initial values following more than 700 h of light soaking. This work has laid the foundation for improving the stability and the industrialization of low-cost DSSCs.

Dendritic Pt thin films are electrodeposited on bulk Pt electrodes in 10×10^-3 mol·L^-1 K₂PtCl₆+3× 10^-4 mol·L^-1 PbAc₂ + 0.5 mol·L^-1 HClO₄ using square-wave potential pulses. As the deposition time increases, the length of the Pt dendrites increases from 400 to 900 nm, and the distribution density of Pt nanoparticles (~10 nm), which consist of coiled Pt dendrites, increases greatly. From hydrogen adsorption/ desorption obtained from cyclic voltammograms (CV), the surface of the dendritic Pt thin film electrodes has a relative roughness (C_r), which increases from 9 to 36 as the deposition time increases. Maximum enhanced IR absorption of adsorbed CO (CO_ad) is observed at the deposition time of 6 min. Anomalous infrared effects for CO_ad are also seen on the dendritic Pt thin film electrodes. The line shapes of CO_ad change with increasing deposition time, in order: bipolar→downward→bipolar→upward→bipolar→ downward bands. Fano-like infrared effects (bipolar), surface enhanced IR absorption (enhanced downward band), and abnormal IR effects (enhanced upward band) are highly dependent on the surface architecture of the nanostructures. The as-prepared dendritic Pt thin films provide model substrates for in-depth studies of the anomalous infrared effects of CO_ad in metal nanostructures.

The synergism between wormlike micelles formed from sodium oleate (NaOA) and hydrophobically modified polyacrylic acid (HMPA) was investigated according to their macroscopic performances and mesoscopic scales, using a combination of viscosity/rheology measurements and dissipative particle dynamics (DPD) molecular simulations. The rheology of NaOA wormlike micelles changed significantly following the addition of a small amount of HMPA, which verified the synergistic effect between them. A peak in the apparent viscosity was observed following an increase in the concentration of HMPA, suggesting that the synergistic effect was restricted by the composition of the mixture. A DPD simulation also confirmed that the solution composition had an influence on the root mean square (RMS) end-to-end distances of HMPA, with the observed value fluctuating according to NaOA and HMPA concentrations. The micellar morphology affected the RMS end-to-end distances of HMPA and the presence of NaOA micelles exerted a significant impact on the extension of HMPA at high HMPA concentrations. A proposed synergistic mechanism has been presented according to the experimental and simulation results.

In this paper, mixed micelle composed of alcohol and polymerizable surfactant (surfmer) were constructed. The aggregated numbers of surfmer (hexadecyl trimethyl allylammonium chloride (C₁₆DMAAC)) in the mixed micelle were measured using a steady-state fluorescence quenching (SSFQ) technique. Using a mixed micellar method with adiabatic polymerization and post-hydrolyzation techniques, the high molecular weight (M_w) micro-block associative polymer of P(AM-NaAA-C₁₆DMAAC) was polymerized. Structures were characterized by Fourier transform-infrared (FT-IR) spectroscopy and ¹³C nuclear magnetic resonance (NMR) spectroscopy. Using rheological experiments, the effects of micro-block length and salt concentration of on the thickening and viscoelastic rheological properties of the polymers were studied. All experiments confirmed that the micro-block length could be adjusted using the mixed micellar method. Increases in the micro-block length were accompanied by decreases in the critical associative concentration (CAC). The viscosities and viscoelastic rheological properties increased to maximum then decreased steady with the length increasing, indicating that the length was at an optimum value.

To investigate the photo-induced hydrophilicity of TiO₂ films and its durability, a series of TiO₂ films containing polyethylene glycol (PEG) 2000 with different contents are prepared. The photo-induced hydrophilicity of the films is investigated by recording the water-droplet contact angle on the films? surface under UV irradiation, and the hydrophilicity durability is monitored under dark storage conditions. The photo-induced hydrophilicity of TiO₂ films and its hydrophilicity durability are enhanced by introducing 2.0% (w) of PEG into the TiO₂ sol. From Fourier transform infrared (FTIR) spectra and ultraviolet-visible diffuse reflection spectra (UV-Vis DRS), we infer that PEG acts as an electron donor to scavenge the photogenerated holes in TiO₂ and promotes the formation of Ti³⁺ sites, which are induced by the Ti⁴⁺ sites accepting the photo-generated electrons of TiO₂. This promotes the formation of hydrophilic sites (the surface hydroxyl species). Compared with the pure TiO₂ film, the Ti³⁺ sites in the TiO₂/PEG films are more stable, which prolongs the hydrophilicity of TiO₂ films under dark conditions. This study is significant for the application of TiO₂ as a self-cleaning material, and is also a facile approach to investigate the transient behaviors of TiO₂ under UV irradiation.

Two manganese oxides with the same nanorod-shaped morphology but different crystal structures, tunnel and layer structures, were synthesized and investigated for selective catalytic reduction of NO_x with NH₃ (NH₃-SCR) at low temperature. Tunneled α-MnO₂ had much higher catalytic activity than layered δ-MnO₂ under the same reaction conditions. Experiment results revealed that the surface area was not the main factor to affect the NH₃-SCR activities over the MnO₂ nanorods and that the activities were structure sensitive. Structure analysis and temperature-programmed desorption experiments of NH₃ (NH₃-TPD) suggested that the exposed (110) plane of α-MnO₂ had many Mn cations in coordinatively unsaturated environment, while all of the Mn cations on the exposed (001) plane of δ-MnO₂ were in coordinatively saturated environment. Thus, α-MnO₂ possessed many more Lewis acid sites. Furthermore, α-MnO₂ has weaker Mn―O bonds and an efficient tunnel structure, which are favorable characteristics for NH₃ adsorption. Moreover, X-ray photoelectron spectroscopy (XPS) and thermal gravimetric (TG) analysis indicated that α-MnO₂ obtained a higher capability for NH₃ and NO_x activation than δ-MnO₂. The crystal structure and surface properties of α-MnO₂ are more suitable to the adsorption of NH₃ and activation of NH₃ and NO_x, which accounts for the higher catalytic activity of the α-MnO₂ nanorods.

Development of a highly active visible-light-driven photocatalyst is a challenge for chemical use of solar energy. In this work, WO₃ was simply mixed with Fe₂O₃, and used thereafter for the photocatalytic degradation of organic dye X3B in the presence of H₂O₂. It was observed that the composite activity was greatly influenced by the catalyst sintering temperature, and by Fe₂O₃ content in the mixed oxide. The optimum sintering temperature and Fe₂O₃ loading were 400 ° C and 1.0% (w), respectively. Through a spin trapping electron paramagetic spectroscopy, it was found that the composite produced a significantly larger amount of hydroxyl radicals, in relative to Fe₂O₃ and WO₃. It is proposed that the observed synergistic effect between Fe₂O₃ and WO₃ is due to the charge transfer between the two oxides, improving the separation of the photogenerated charge carriers, and thus accelerating the photocatalytic degradation of X3B.

Parathyroid hormone 1 receptor (PTH1R) is a member of the class B G-protein coupled receptor (B-GPCR) family and is involved in bone formation. Its substrate parathyroid hormone (PTH) and its analogues are being developed as anti-osteoporosis therapeutics. The structure-based rational drug design of PTH1R substrates has been hampered by the lack of experimentally determined three-dimensional (3D) structures from techniques such as nuclear magnetic resonance (NMR) and X-ray crystallography. Here, we have constructed a 3D model of PTH1R including its extracellular domain (ECD), transmembrane domain (TM) and other domains using a homology modeling approach. In addition, to capture the ligand-receptor interactions, we have manually docked human parathyroid hormone (1-34) into the top scoring receptor model, and subjected the PTH-PTH1R complex to an unconstrained energy minimization. The integral 3D receptor model provides an easier way to understand the interactions involved at the TM, ECD, and other domains. Furthermore, the parameters of hydrogen bonding, hydrophobic, and other interactions from the ligand-receptor model, enabled us to elucidate the important interactions between PTH (1-34) and PTH1R. This ligand-receptor model could potentially serve as a tool for structure-based virtual screening in the development of non-peptide based anti-osteoporosis drugs.

Recently, gel chromatography has been demonstrated as an effective method for the separation of single-walled carbon nanotubes (SWCNTs) according to their electronic type and structure. The separation of SWCNTs was thought to result from the different affinity forces between the gel and various SWCNTs. Based on this method, we investigated the effect of ultrasonic time on the dispersion and separation of metallic and semiconducting SWCNTs. At a low ultrasonic power, with the increase of ultrasonic time, better monodispersed SWCNTs in sodium dodecylsulfate (SDS) aqueous solution were obtained. The UV-visible-near infrared (UV-Vis-NIR) absorption, Raman and photoluminescence (PL) spectroscopic characterizations confirmed that under the condition of ultrasonication (2 h), higher-purity metallic tubes and semiconducting tubes with different diameter distributions could be obtained. We believe that the control of the ultrasonication time may tune the mono-dispersity and the length of SWCNTs, which would further influence the difference in affinity forces between various SWCNTs and the gel, therefore leading to different separation results.

Well-crystallized one-dimensional (1D) structural SnO₂ belts are synthesized using a simple water-assisted chemical vapor deposition method. To increase the yield of SnO₂ belts, small Sn particles with and without Au-modifications are used as source materials to grow different width SnO₂ belts. Dye-sensitized solar cells (DSSCs) fabricated using the composite (nanoparticle/nanobelt) SnO₂ thin films, are used to evaluate the electron transport properties of the SnO₂ belts. Pastes containing different ratios of nanoparticles and belts are used to prepare the composite film by the doctor-blade method. The DSSCs exhibit different photovoltaic performances which are dependent on the nanoparticle/nanobelt ratio and width of the SnO₂ belts in the thin film. The enhanced electron transport properties of the composite films containing the SnO₂ belts is evaluated using intensity modulated photocurrent spectroscopy (IMPS). 1D SnO₂ belts with a particular belt width improve the photovoltaic performance by providing electron paths to accelerate electron transport in the composite nanocrystalline thin films.