Conductivity is important in the investigation of the micellization behavior of ionic surfactants in an aqueous solution. We review this sensitive technique and discuss methods to determine the critical micelle concentration (cmc) and the degree of dissociation of the micelle( α) in detail. We also investigatea special situation analysis for conductivity curves and premicellar behavior. This method is useful for the investigation of surfactant systems in which strong intermolecular interactions occur.

Non-covalent complexes of α-, β-, and γ-cyclodextrin (CD) with the antidepressant compound SIPI5358 were investigated by electrospray ionization mass spectrometry (ESI-MS), tandem mass spectrometry (MS/MS), UV spectroscopy, and fluorescence spectroscopy. The ESI-MS experimental results revealed that SIPI5358 reacted with the α-, β-, and γ-CD to form complexes with different coordination numbers. The tandem mass spectra further confirmed the formation of non-covalent complexes of SIPI5358 with β-CD. Binding of the complexes was also confirmed by UV as well as fluorescence spectra. The formation constant K_f was determined by fluorescence spectroscopy to be 3.45 ×10³ mol·L^-1 for the complex of SIPI5358 and β-CD.

The potassium salt of 7-hydroxy-4,6-dinitro-5,7-dihydrobenzofuroxanide (KDNBF) was prepared by a reaction of the sodium salt of DNBF with potassium sulfate in aqueous solution. Samples of KDNBF with different morphologies were obtained by adding various surfactants. The effect of a single surfactant on the sample morphology was determined withpowder X-ray diffraction (XRD) data. The thermal decomposition behaviors of KDNBF with different shapes were studied using differential scanning calorimetry(DSC) and thermogravimetry(TG) analyses. The kinetic parameters of the exothermic processes were studied by applying the Kissinger 's and Ozawa-Doyle 's methods. The results show that the spherical sample has a lower decomposition temperature and higher reaction activation energy than the other forms of the sample. Furthermore, impact sensitivity, flame sensitivity, and friction sensitivity tests indicated that the spherical KDNBF sample has stronger friction and impact sensitivities and weaker flame sensitivity.

We investigated the effect of plating parameters on the coating morphology and grain size of copper using a novel citrate bath. The structure and deposit were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The copper plating bath was applied to a micro-electro-mechanical system (MEMS). Results show that an even and compact copper coating was obtained for the fine grains using plating parameters of 6g·L^-1 Cu²⁺, pH=7.0-8.5, 1-2A·dm^-2, 45 ℃, and bath agitation. The deposit consists of pure copper in a fcc polycrystalline structure.A planar inductor was successfully fabricated by MEMS using this bath and its maximum quality factor was 12.75, which satisfies the design requirements.

The growth characteristics of sulfate reducing bacteria (SRB) in real reclaimed water were studied. Characteristics of the biofilm and its main components on the surface of stainless steel 304 (SS304) sample immersed in reclaimed water with SRB, the electrochemical behavior of the interface between the SS304 sample and the biofilm were investigated using atomic force microscopy (AFM), scanning electron microscopy (SEM), energy disperse spectroscopy (EDS), and electrochemical impedance spectroscopy (EIS). The results show that this strain of SRB can survive in reclaimed water. A biofilm formed on the surface of SS304 and consisted of microbial cells, a carbohydrate component from extracellular polymeric substances (EPS) and a corrosion product such as FeS. During the early immersion period (before 7d), the impedance value mainly originated from the contribution of passivation film on the SS304 electrode surface. During the later immersion period (after 14 d), the impedance value was mainly due to the combined effect of the passivation filmand the biofilmon the SS304 electrode surface.

Anodic electrochemical polymerization of N,N'-ethylenbis (salicylideneaminato) nickel(II) ([Ni(salen)]) in tetrabutylammonium perchlorate (TBAP)/acetonitrile (AN) was investigated by the linear sweep potential method. The sweep rate ranged from 5 to 150 mV·s^-1. The effect of sweep rate on the growth of poly[Ni(salen)] was studied by Coulomb analysis. The morphologies of poly[Ni(salen)] were characterized by field emission scanning electron microscopy (FESEM). The relationship between the growth rate of poly[Ni(salen)] (dΓ/dm) and the sweep rate (v) fits the exponential degradation equation. The content of the redox center for poly[Ni(salen)], grown at sweep rate of 20 mV·s^-1, reaches a maximum and then decreases as the sweep rate increases because monomer diffusion restricts the growth of poly[Ni(salen)]. We studied the effect of polymerization sweep rate on the kinetics of the as-grown poly[Ni (salen)] by cyclic voltammetry. The charge diffusion coefficient (D) of poly[Ni(salen)] grown at a sweep rate of 20 mV·s^-1 was found to be the highest.

Solid alkaline electrolyte membranes were prepared using poly(vinyl alcohol)/poly(vinyl pyrrolidone) (PVA/PVP) by KOH doping. The composition, microstructure, thermal stability, ionic conducitvity and methanol uptake of the composite membranes were investigated in detail. The wholly transparent, homogeneous and compact PVA/PVP/KOH composite membranes were obtained when m(PVA) :m(PVP)=1 :0.5 in a mass ratio and no obvious phase seperation was observed. The ionic conductivity and thermal stability of the PVA/PVP membranes increased greatly with increasing the content of PVP. A high ionic conductivity of 2.01 ×10^-3 S·cm^-1 was obtained whena mass ratio of m(PVA) :m(PVP)=1 :1 was used. In additon, the methanol uptake of the PVA/PVP/KOH membranes showed almost no change after conditioning at elevated temperatures and it was 4 times lower than that of the Nafion 115 membrane after conditioning at 100 ℃. These membranes are, therefore, promising solid alkaline electrolyte membranes for use in alkaline direct methanol fuel cells at elevated operating temperature.

The electroosmotic drag and the corresponding mechanism of water molecules in hydrated potassiumperfluorosulfonate electrolyte polymer membrane were studied using molecular dynamics simulations, and therelationship between the membrane structure and electroosmotic drag characteristics was analyzed. It is concluded thatvelocities of both H₂O and K⁺ obey the Maxwell velocity distribution function without external electric field applied. Ifan appropriate electric field is applied, the velocities of H₂O and K⁺ still obey the Maxwell velocity distribution in thedirection perpendicular to the electric field, and obey the peak shifted Maxwell velocity distribution in the directionparallel to the electric field. The peak shifting velocities coincide with the average transport velocities of H₂O and K⁺ induced by the applied electric field, and could be applied to evaluate the electroosmotic drag coefficient of water. Theresults also show that the average number of water molecules in the first coordination shell of K ⁺ is 4.04, and theaverage transport velocity of these water molecules is about 57% of that of K ⁺. The electroosmotic drag coefficientcontributed by these water molecules is about 77% of total the electroosmotic drag coefficient(2.97) .

An oil in water (O/W) emulsion with a resorcinol and formaldehyde (R+F) water solution as the external phase and liquid paraffin as the internal phase together with Span 80/Tween 80 as emulsifiers was obtained. Carbon materials were prepared by polymerization of the emulsion, followed by carbonization for template removal. The effect of catalysts on the morphologies of the carbon materials was investigated. The results indicate that the resultant representative carbons area type of porous carbon foam and possess pore walls and pores of 1-2 μm in size when NaOH is used as a catalyst. However, monolithic carbon materials consisting of microspheres or intertwinded wormlike particles were prepared using ammonia as an alternative catalyst. The diameters of these microspheres or particles were mainly around 1-2 μm and these dimensions are similar to the pore sizes of the carbon foams. We find that ammonia causes the initial O/W emulsion system to experience a phase inversion towarda W/O high internal phase emulsion.A mechanism involving intermolecular H-bond interactions and cohesive energy theory is proposed to explain the catalyst-induced phase inversion phenomenon as well as the formation of carbon materials with different morphologies.

We used time-resolved optical waveguide spectroscopy (OWGS) to in-situ measure visible absorption spectrum for methylene blue (MB) adsorbed ona hydrophilic glass waveguide from an aqueous solution containing proteins such as bovine serum albumin (BSA) and hemoglobin (Hb). The competitive adsorption of MB and the protein was detected at a solution pH lower than the isoelectric point of the protein. Since the competitive adsorption behavior of MB and the protein is very sensitive to the protein concentration, the protein content in the mixed solution was readily determined by time-resolved OWGS. In addition, a kinetic equation for the competitive adsorption of the two molecules was deduced based on the Langmuir adsorption isotherm. The best fit of the measured time course of the absorbance with the theoretical kinetic equation reveals that the number of MB molecules adsorbed on the surface exponentially decreases with time after reaching a maximum.A quasi-linear relationship between the fitting parameters and the protein concentration was also obtained.

NO_x adsorption in silver-exchanged aluminophosphate molecular sieves ([Ag]-SAPO-5 and [Ag]-TAPO-5) was investigated using the density functional theory (DFT). Equilibrium structure parameters and adsorption energies were obtained and compared. The results indicated that the η¹-N mode was more stable than the η¹-O mode. The adsorption energy values of NO_x followed the order: NO₂>NO>N₂O. Compared to the free gas state, the bond parameters of NO and NO₂ in the adsorbed state changed more than that of N₂O in [Ag]-SAPO-5 and [Ag]-TAPO-5. Moreover, [Ag]-SAPO-5 and [Ag]-TAPO-5 had a higher activation for the NO_x molecule compared to [Ag]-AlMOR. The resistance capabilities of [Ag]-SAPO-5 and [Ag]-TAPO-5 to SO₂,H₂O, and O₂ were also studied and analyzed. In addition, the interaction mechanism of NO_x in silver-exchanged aluminophosphate molecular sieves was investigated using natural bond orbital (NBO) analysis.

The lateral hopping of tert-butylamine (t-BA) molecules ona Cu(111) surface was studied by scanning tunneling microscopy (STM) at 78 K. The hopping probabilities of the molecules in the tunneling junction were found to depend linearly on the applied tunneling current, indicating a single electron-induced process. Hopping probabilities under an electric field of opposite polarity was found to be different. This non-equivalence is attributed to an electric field assisted diffusion where the adsorption energy and the diffusion barrier of the t-BA molecule are different when the polar molecule is subjected to opposite electric fields.

Monometallic Pd and Pt as well as bimetallic Pd:Pt catalysts (Pd₁Pt₁, Pd₁Pt₄, and Pd₄Pt₁) with Pd/Pt molar ratios of 1:1, 1:4, and 4:1 supported on SiO₂-Al₂O₃ were prepared by incipient-wetness impregnation and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), CO chemisorption, and X-ray photoelectron spectroscopy (XPS). Their catalytic activities toward naphthalene hydrogenation and the sulfur tolerance of these catalysts were investigated. We found that naphthalene conversion, selectivity toward decalin, and the trans-/cis-decalin yieldratio on Pd₄Pt₁ were 98.2%,93.6%,and 7.8,respectively,which are higher than those on Pd(97.5%,59.1%, 4.3) and Pt (96.8%, 39.9%, 2.9). The rate of naphthalene hydrogenation on the three catalysts increased according to: v_Pd4Pt1>v_Pd>v_Pt. In the presence of dibenzothiophene (DBT), the naphthalene conversion and selectivity toward decalin for Pd₄Pt₁ were still the highest. The trans-/cis-decalin ratio was not affected on the Pt catalyst, but it did decrease slightly on Pd₄Pt₁ and it decreased observably on the Pd catalyst. The Pd₄Pt₁ catalyst also presented the highest naphthalene conversion and selectivity toward decalin among the three bimetallic catalysts studied in the presence and absence of DBT.

We prepared a 4%Ru-9%La/γ-Al₂O₃ catalyst by impregnation method and characterized it using X-ray diffraction(XRD) ,X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The catalyst was used for the hydrogenation of methyl propionate. The effects of solvent, inorganic salt additive, steric as well as electronic factors of the substrate on the hydrogenation of a carboxylic ester were investigated. We found that both water and the Co(NO₃)₂ additive obviously improved the hydrogenation of methyl propionate, the conversion of the substrate and the selectivity for propanol. The promotional effects of water and Co²⁺ are attributed to polarization of the C=O bond in the carboxyl group of the substrate molecule by the formation of a hydrogen bond between water and the carboxylic group and the coordination of Co²⁺ to the carboxylic group. This is favorable for an attack on the carbon atom of the carboxyl group by the activated hydrogen. Similarly, the electron -withdrawing group in the substrate molecule also caused the high positive charge of carbon in the carboxyl group. The highly positive charged carbon is beneficial for the hydrogenation reaction. In addition, an increase in the steric hindrance of the substrate molecules was not favorable for the adsorption of the substrate on the catalyst and, therefore, the reaction rate decreased.

Co-B catalysts supported on ZrO₂ (prepared by alcogel nitrogen thermo-treatment method), carbon nanotubes (CNTs), and mesoporous SBA-15 as supports were prepared by chemical reduction method and characterized by X-ray diffraction (XRD), nitrogen physisorption, transmission electron microscopy (TEM), inductively coupled plasma -atomic emission spectrometry (ICP-AES) and X-ray photoelectron spectroscopy (XPS). Hydroformylation of 1-octene was used as a probe reaction to investigate the catalytic performance and stability of the catalysts in recycles. The as-prepared Co-B catalysts showed amorphous characteristics and the support structures were unchanged. The reaction results reveal that the catalytic activities of Co-B/CNTs, Co-B/ZrO₂ and Co-B/SBA-15 in the hydroformylation of 1-octene were comparatively high. However, the catalytic activities decreased upon recycling. Nevertheless, the Co-B/ CNTs and Co-B/SBA-15 were relatively stable compared with Co-B/ZrO₂.

The photocatalysts CdS and p-n coupled semiconductor photocatalysts CoO/CdS(p-CoO/n-CdS) were prepared using cadmium acetate, lauryl mercaptan, cobalt acetate, and stearic acid by a new method. The structural and optical properties of CdS and p-CoO/n-CdS were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM),N₂ adsorption -desorption, and ultraviolet -visible diffuse reflection spectroscopy (UV-Vis DRS). The results showed that the particles of CoO compactly connected with the particles of CdS in the p-CoO/n-CdS. The particle size of CdS was about 100 nm and the crystalloid of CdS was hexa n spiauterite. The particle size of CoO was about 10 nm, and the distribution of particles size was uniform. The results of UV-Vis DRS showed that the nano-CdS particles could absorb the visible light at wavelengths between 400 and 550 nm which is characteristic absorption of CdS in the visible region. The photocatalytic activity of the photocatalyst was evaluated by photocatalytic degradation of methyl orange (MO). The results showed that the photocatalytic activity of p-CoO/n-CdS was much higher, which was 2.2 times than that of CdS on the photocatalytic degradation of methyl orange. The results of photocorrosion test showed that the photocorrosion rate of CdS was two or more times than that of p-CoO/n-CdS, which indicated that CoO coupled with CdS could effectively restrain the photocorrosion of CdS.

ACo₂O₄(A=Mg, Ni, Zn)andACo₂O₄/HZSM-5 (A=Mg, Fe, Ni, Cu, Zn, Zr, La) catalysts were synthesized by the citric acid -ligated combustion method and by low -temperature complex impregnation, respectively. The catalysts were characterized by X-ray diffraction (XRD), ammonia temperature -programmed desorption (NH₃-TPD), scanning electron microscopy (SEM), and energy dispersive X-ray microanalysis (EDS). The performance of the catalysts was evaluated with micro fixed bed reactor. The results showed that the catalytic activity was affected by the A-site ion, and when theA -site ion was Ni, Fe, Zr, or La, the catalysts had better catalytic activity and the temperature of N₂O decomposition was lower. Compared with ACo₂O₄, the ACo₂O₄/HZSM -5 catalyst had better catalytic activity. ACo₂O₄ was present as ultrafine particles on the HZSM-5 zeolite and the ACo₂O₄/HZSM -5 catalyst had od acidity. All these factors are useful in improving the performance of these catalysts.

Transparent anatase titanium dioxide sol was prepared by the hydrothermal treatment of the home-made water soluble peroxotitanium acid (PTA). The nanorod-like TiO₂ nanocrystals witha mean diameter of less than7 nm were obtained in the absence of organic compounds. In order to eliminate the large pores derived from eletrode sintering and improve the connectivity among particles in the porous TiO₂ electrode, the as-prepared TiO₂ sol was infiltrated to the porous TiO₂ photoanode for dye sensitized solar cells (DSSCs). As a result, small nanocrystals of titanium dioxide attached to the surface of porous titanium dioxide as well as filled the large pores produced by photoanode sintering. The efficient electron transport networks were formed inside the porous titanium dioxide, which was confirmed by scanning electron microscope (SEM) and optical profilometry. The modified TiO₂ film as the anodic electrode was used for the DSSCs and assembled into solar cells. Consequently, the overall energy conversion efficiency of the DSSCs was significantly enhanced by 64% after the low-concentration TiO₂ sol infiltration.

White polymer light -emitting diodes (WPLEDs) were fabricated by spin coating method using two complementary colors. The device structure used here is ITO/PEDOT (40 nm)/emitting layer (80 nm)/Ba (4 nm)/Al (120 nm). When the mass ratio of PVK:OXD -7:iridium bis(2 -(4,6 -difluorophenyl) -pyridinato -N,C2)picolinate (Firpic):tris(3 -(2,6 -dimethylphenoxy) -6-(thiophen -2-yl)pyridazine)iridium (Fs-1) was 63:27:10:0.25, white light with Commission Internationale deL 'Eclairage (CIE) coordinates of (0.30, 0.39) was obtained. The maximum current efficiency was 10.8 cd·A ^-1 and the maximum brightness was 4200 cd·m ^-2. To improve the hole -electron injection balance and the device 's character, a thin layer of water -soluble electronic transporting material was used to modify the cathode. In this case, efficient white light emission with a maximum current efficiency of 13.1 cd·A^-1 anda maximum brightness of 6069 cd·m^-2 was obtained. Using poly[(9,9 -bis(3 '-(N,N-dimethylamino) propyl) -2,7 -fuorene) -alt -2,7 -(9,9 -dioctylfuorene)] (PFN) (20 nm)/Al (120 nm) as the cathode resulted in CIE coordinates of (0.33, 0.39) and the EL spectrum was also found to be quite stable. The effects of charge trapping and energy transfer on device performance were discussed by considering the photoluminescence (PL) and electroluminescence (EL) spectra as well as the energy band diagramof the device.

Plenty of attention has been paid to obtaining single-walled carbon nanotubes (SWCNT) with single conductive properties so that they can be applied in various fields. Among the separation techniques used for metallic (m-) and semiconducting (s-) single-walled carbon nanotubes, agarose gel electrophoresis (AGE) is thought to be a relatively simple and low-cost method. In this work, we used UV-visible-near infrared (UV-Vis-NIR) absorption spectroscopy to study the effect of NaCl on the separation of SWCNT by AGE. Our results show that the addition of NaCl greatly influences the separation of the SWCNT. At a NaCl concentration of less than 70 mmol·L^-1, the relative content of s -SWCNT increased after separation and at a NaCl concentration of higher than 70 mmol·L^-1, the separation of m-SWCNT and s-SWCNT was restrained as the concentration of NaCl increased. At a NaCl concentration of 160 mmol·L^-1, the separating efficiency of the system dropped markedly. We suggest that the addition of NaCl may change the adsorption properties of the surfactant towards m-SWCNT and s-SWCNT.

The tetradentate coordination of bisdipyrrin ligands from cyclooctapyrroles with single and double metal cation metalations generates helical chirality and brings about recent research interests in supremolecular chemistry. In this study, eight divalent metal cations (M(II), M=Ca, Mg, Mn, Zn, Cu, Ni, Fe, Co) in the formation of the singly metalated complexes (1M) and binuclear metal complexes (2M) are systematically investigated to appreciate their structure, spectroscopy, and reactivity properties by using density functional theory (DFT), time-dependent DFT, and conceptual DFT approaches. Their bonding properties are analyzed by the natural bond orbital (NBO) analysis. The simulation results revealed that structure, spectroscopy, and reactivity features of the 1M and 2M complexes are markedly different from their precursor bisdipyrrin (1H) with a larger electrophilicity index, smaller chemical hardness, and distinctive dual descriptor. UV-Vis spectra show diminished peaks with red shifts due to metalation.A few linear structure-reactivity relationships stemmed from these structure and reactivity properties have been obtained with the correlation coefficient (R²) between 0.858 and 0.986. The results can provide in-depth insights for these complexes from structure and reactivity viewpoints.

Characteristics of the one electron redox behavior of hydrophobic amino acids in gas phase were calculated with density functional theory at the B3LYP/DZP++ level. For glycine, alanine, proline, valine, leucine, and isoleucine with small side chains, the computational results indicate that the negative charges are removed from the atoms of their amino, α-carbon, and carboxy moieties in one electron oxidation reactions. This yields large adiabatic ionization potentials (AIP) of 8.52-9.15 eV. The AIPs of cysteine, methionine, phenylalanine, tyrosine, and tryptophan decrease because of the larger amount of negative charge removed from the atoms in their side chains. The attachment of one electron to the molecules of hydrophobic amino acids leads to anions in which the extra electron is bound to the H atoms of the carboxyl or amino groups and to their valence orbitals, reflecting the double nature of the dipole -bound state and the valence state. The electron affinities (EA) for the amino acids are small and negative ranging from -0.08 to -0.63 eV. The molecules of the hydrophobic amino acids are oxidized or reduced with difficulty in gas phase because of their high VIPs and negative EAs.

A series of 6-aryl-2-methylimidazo[1,2-α]pyrazin-3-(7H)-ketone based derivatives MIPa-MIPd (cypridina luciferin analogues) were investigated using the B3LYP/6-311+G(d,p) method, and we modeled a 6-site replacement by different substituents. The effect of different substitutions on cypridina luciferin analogues in their transition from anions to free radicals was studied by electron extraction potentials (EEP) and natural charge population analysis (NPA) in gas phase, dimethyl sulfoxide (DMSO), and diglyme (DG). The calculated results indicated that MIPb (3-indolyl as the substituent) had a lower EEP and a larger natural charge population change occurred at the MIP moiety in DG when transitioning from the anion to its free radical than in the other solvents. We also showed that 3-indolyl, as a substituent, accelerated the luminescent reaction of MIP.

We investigated the photodissociation mechanism of cyanogen azide (N₃CN) at the MRCI+Q//CAS(10,9)/6-311+G(2df) level of theory using the multi-reference state method. The optimized structures and energies of the minima, transition states, singlet/singlet conical intersection and singlet/triplet crossing points of the ground and low-lying excited states were obtained to explore the potential energy surfaces of N₃CN. The vertical excited energies calculated at the MRCI+Q//CAS(10, 9) level were compared with the experimental data. It is shown that N—N bond fission to form N₂+NCN is the predominant dissociation pathway on the S0, S1, S2, and T1 surfaces whereas the C—N bond fission channel is the minor pathway. The 220 nm absorption peak observed experimentally corresponds to an excitation from the S0 to the S1 state leading to the major photodissociation product NCN[a¹Δ_g]. The 275 nm absorption peak corresponds to the S0-T1 transition leading to the formed ground-state product NCN[X³Σ^-_g ] via the barrierlessly direct dissociation in the T1 state. Our theoretical results agree well with experimental observations.

We calculated the electrostatic potential (ESP) and electric field (EF) of periodic liquid water systems using the quantum chemistry software package, Crystal. We proposea method to obtain atomic partial charges rapidly for periodic systems based on first-principles calculations. In this method, the average electrostatic potential φ^mean, which is introduced to meet the periodic boundary condition, is taken as a parameter during the least squares fitting of the ESP from first-principles calculations and used in the Ewald summation. A comparison of the two methods, i.e., ESP and EF fitting, reveals that the relative root mean-square deviation (RMS) of the former method is only 2%-3%, which is one order of magnitude smaller than that of the latter method. In addition, the distribution of the derived atomic partial charges and dipole moments for the water system are discussed using four charge restrained fits.

The band structures, density of states (DOS), and magnetic properties of wurtzite Mn-AlN and Cr-AlN were studied using density functional theory (DFT) with the generalized gradient approximation (GGA) for the exchange-correlation potential. The results indicate that the half-metallic gap of Mn-AlN and Cr-AlN decreases as the Mn/Cr doping concentration increases. This probably results froman increase in the interaction between Mn and Mn or Cr and Cr atoms and a decrease in the hybridization of Mn/Cr 3d and N 2p states with increasing the Mn/Cr doping concentration, which results in a smaller spin-exchange splitting so the half-metallic gap is reduced. Additionally, with the same doping concentration, the half-metallic gap of Mn-AlN is larger than that of Cr-AlN. This is due to the lower Mn 3d states compared to the Cr 3d states and the hybridization of Mn 3d and N 2p states being stronger in Mn-AlN, which leads to a larger spin-exchange splitting so the conduction band minimum of the down spin bands moves far away fromthe Fermi level and the half-metallic gap of Mn-AlN becomes larger.

Experimental values of the coagulation rate constant for colloidal particles are known to be much lower than the theoretical values. Only the particle's geometric radii are used in the theoretical derivation of coagulation rate constant. However, it should actually be the hydrodynamic radius (larger than the geometric radius) that determines the particles' diffusion speed and thus the coagulation rate. Therefore, it is one of the reasons that cause the experimental coagulation rate constant lower than the theoretical one. Many factors affect the hydrodynamic radius and among them the electric double layer can significantly swell the hydrodynamic radius, which lowers the coagulation rate. The thickness of the electric double layer changes with the ionic strength of the solution. To correct the error caused by ne-glecting the difference between the geometric and hydrodynamic radius, a correction factor, which is the ratio of geometric radius to hydrodynamic radius, is introduced in this study. The geometric radius and the hydrodynamic radius were determined by scanning electron microscopy (SEM) and dynamic light scattering (DLS), respectively. Two different sized polystyrene microspheres were used to investigate the effect of ionic strength on the difference between the experimental coagulation rates and the theoretical ones. The results show that for slow aggregation, the rate constant calculated by using the hydrodynamic radius can be lower than its theoretical value by about 8% for microspheres with radius of 30 nm. This difference decreases with the increase of ionic strength. The effect of the hydrodynamic radius on the coagulation rate is negligible for fast aggregation.

We correlated the protective ability of osmolytes on proteins with their fractional polar surface area (f_pSA) and molecular volume (V). Thus, both parameters need to be considered when the protective ability of osmolytes is analyzed. We carried out molecular dynamics simulations of the chymotrypsin inhibitor 2 (CI2) in different osmolytes to probe the molecular basis of the stabilizing effect. Based on the simulation data, a one-dimensional structure parameter was first calculated. We then used a statistical bivariate fit model to obtain a theoretical model, which represents the stability capacity of the osmolytes. Finally, the model was used to analyze the correlation between the two parameters (f_pSA and V) and the protective ability of the osmolytes. We found that the one-dimensional structure parameter characterized the protective ability of the osmolytes well. Using this model, the protective stability of the osmolytes can be analyzed accurately. The inclusion of V and the two-order term of f_pSA greatly increases the accuracy of the model. The protective capacity of the osmolytes increases with V. In addition, we introduced the two-order term of f_pSA into the fit formula. We found that the f_pSA of the osmolytes is negatively correlated with its protective ability when it is less than 0.7. However, when the f_pSA of the osmolytes is larger than 0.7, it is positively correlated with its protective ability.

The key to constructing a protein microarray is the stable immobilization of proteins and the retention of their biological activities. In this study, immobilization of the carcinoembryonic antigen (CEA) antibody onto a silicon dioxide surface was investigated by physical adsorption, direct chemical covalent conjugation, spacer-added chemical covalent conjugation, and biological affinity interactions. Based on the specific antibody-antigen interactions, the sandwich reaction, enzyme-linked immunosorbent assay (ELISA) was chosen to evaluate various immobilization strategies. The most efficient immobilization strategy was with glutaraldehyde as a coupling reagent between the CEA antibody and the amino surface. The attachment of a spacer-armcomprising poly-L-lysine significantly improved the immobilization efficiency and simultaneously decreased nonspecific adsorption. High immobilization efficiency and stronger nonspecific adsorption were also observed when the CEA antibody was immobilized by bioaffinity interactions.

In proteins, cation-π interactions are formed between positively charged amino acids (Lys, Arg) and aromatic amino acids(Phe, Tyr, Trp). We investigated the cation-π interactions in two typical folding structures of α/β proteins, namely, the singly wound structure and the doubly wound structure. The results reveal that: (1) The distribution density of cation-π interactions in singly wound structures is about 2.6 times as high as that in doubly wound structures; (2) In singly wound structures, a correlation is observed between the amount of residues and their cation-π interactions while no correlation is observed in doubly wound structures; (3) Lys, Arg and Tyr in singly wound structures participate more easily in cation-π interactions than those in doubly wound structures; (4) Arg-Phe pairs are preferred in doubly wound structures while Arg-Tyr pairs are preferred in singly wound structures; (5) In singly wound structures, 65%of the cation-π interactions formarrays or distribute between the starting point and the end point in the structures.

A three dimensional structure model of the adenosine A₁ receptor was built using homology modeling. The anta nist DPCPX was docked into the model protein to form a receptor-ligand complex. A molecular dynamics simulation over 5 ns was performed for this complex. We selected 12 protein structures, including the average structure obtained from the last 2 ns of the simulation and 11 frames extracted after equilibration for the study. A database comprising 52 active anta nists and 1000 decoys was then docked into the 12 protein models using DOCK, VINA, and LD software packages and these molecules were ranked by their docking scores. The best model protein with the highest enrichment factor (EF) and the largest area under the ROC (AU-ROC) was chosen for further study. The results from the enrichment factor at 10%of the ranked database (EF₁₀) and AU-ROC calculations indicate that LD is the best virtual screening software for the adenosine A₁ receptor. LD docking results suggest that optimized adenosine A₁ receptor protein structures, Favg and F5, can be used for virtual screening and for novel design to discover more potent anta nists.

We synthesized Sn -doped ZnO nanoneedles on Si(111) substrates in two steps: sputtering and thermal oxidation. First, a thin layer of the Sn :Zn films was deposited onto the Si(111) substrates ina JCK -500A radio -frequency magnetron sputtering system. Sn-doped ZnO nanoneedles were then grown by simple thermal oxidation of the as-deposited films at 650 ^oC in Ar atmosphere. The structural, componential, and optical properties of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high -resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) spectroscopy, and photoluminescence (PL) spectroscopy. The results reveal that the ZnO nanoneedles doped with 2.5%(x, atomic ratio) Sn are single crystalline with a wurtzite hexa nal structure. The lengths of the grown nanoneedles vary between 1 and 3μm. The root diameters of the needles range between 200 and 500 nm while the tips have an average diameter of about 40 nm. Moreover, most of the Sn-doped ZnO nanoneedles are of high crystal quality. Room temperature PL spectroscopy shows a blue-shift from the bulk bandgap emission, which can be attributed toa Sn composition in the nanoneedles as detected by EDX. Based on the reaction conditions, the growth mechanism of the Sn-doped ZnO nanoneedles was also discussed.

Coumarin-containing disulfide (C-S-S-C) was designed and synthesized, which could be used as chain transfer agent with tributylphosphine and water. With N-isopropyl acrylamide (NIPAAm) as monomer and azodiiso- butyronitrile (AIBN) as initiator, an amphiphilic photosensitive telechelic polymer (C-PNIPAAm) was synthesized. The polymer was characterized by Fourier transform infrared (FT-IR) spectroscopy, gel permeation chromatography (GPC) and proton nuclear magnetic resonance spectroscopy (¹H-NMR). We found that the polymer can form micelles in water itself with fluorescein as a hydrophobic agent. When irradiated by UV light (λ>310 nm), the coumarin unit at the end of the polymer chain was photodimerized, which changed the micelle structure and hydrophobic fluorescein was effectively released to the water. Dynamic laser scattering (DLS) showed that the average diameter of the micelles increased from56.6 nmto 101.0 nmafter irradiation.

A systematic study of the electronic structures of sphalerite containing fourteen kinds of natural impurities was performed by the density functional theory. The results show that Mn, Fe, Co, Ni, Cu, Cd, Hg, Ag, Pb, and Sb impurities narrow the bandgap of sphalerite and cause the absorption edge to increase. For all impurities except Cd and Hg, the Fermi level shifts to a higher energy level and impurity levels appear in the forbidden band. Fe, Ga, Ge, In, Sn, and Sb impurities change the sphalerite froma p-type toa n-type semiconductor while Mn, Co, Ni, Cu, Cd, Hg, Ag, and Pb impurities have no effect. Cu impurity changes the sphalerite from a direct bandgap to an indirect bandgap type semiconductor.