Electrospinning of curcumin loaded chitosan/poly （lactic acid） nanofilm and evaluation of its medicinal characteristics

The curcumin loaded chitosanlpoly （lactic acid） （PLA） nanoflbers were produced using electrospinning. Box-Behnken experimental design was used for the optimization of variables （-1, 0, ＋ 1 coded level） like chitosan/PLA strength （% w/v）, curcumin strength （% w/v） and applied voltage （kV） to obtain uniform fiber diameter. The morphology of nanofibers was shown by SEM. Molecular interactions and the presence of each chemical compound of curcumin loaded chitosanlPLA fibers were characterized by FTIR and EDX analysis. Antioxidant, drug release and in vitro cytotoxicity tests were performed to evaluate the suitability of nanofibers that would be used for wound healing. In vivo wound healing studies on excision and incision wounds created on rat model showed significant reduction of wound area when compared to untreated. The better healing efficiency can be attributed to the presence of curcumin and chitosan.     

New Nanocomposite Materials by Incorporation of Nanocrystalline TiO2 Particles into Polyaniline Conductive Films

This work is focused on the combination of two building-blocks, nanocrystalline TiO2 particles and polyaniline conductive films （PAni）. The preparation of new nanostructured composite materials, displaying electron- and proton-conductive properties, to be used for the fabrication of new and superior energy storage devices was envisaged. The semiconducting TiO2 nanoparticles were obtained by means of a hydrothermal route. The PAni films were prepared on glassy carbon electrodes by electrochemical polymerization, under potential dynamic conditions. After characterization by X-ray diffraction, transmission electron microscopy or scanning electron microscopy and electrochemical techniques, the nanocrystalline particles were immobilized in the polymer matrix. The incorporation of the TiO2 was achieved using two distinct approaches： during the polymer growth or by deposition over previously prepared PAni films. The results demonstrate that the PAni morphology depends on the experimental conditions used during the polymer growth. After TiO2 immobilization, the best electrochemical response was obtained for the nanocomposite structure produced through the TiO2 incorporation after the PAni film synthesis. The modified electrodes were structurally and morphologically characterized and their electro-catalytic activity towards the hydrogen evolution reaction was analyzed. A new electrochemical performance related with the oxidation of molecular hydrogen entrapped in the PAni-TiO2 matrix was observed for the modified electrode after TiO2 incorporation. This behavior can be directly associated with the synergetic combination of the TiO2 and PAni, and is dependent on the amount of the semiconductor.     

CaCO3/TiO2 Nanoparticles Based Dye Sensitized Solar Cell

In this communication,the synthesis and structural,morphological,optical,and photo-electrochemical properties of TiO_2 and CaCO_3/TiO_2 nanoparticles as well as their applications in dye sensitized solar cells(DSSCs),have been reported.In an X-ray diffraction pattern of CaCO_3/TiO_2 nanoparticles,the peak at 29.41°of CaCO_3 has been detected,demonstrating its coating on the surface of TiO_2,which is further verified using high resolution-transmission electron microscopy,energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy.The strong quenching in photoluminescence emission,in the case of CaCO_3/TiO_2nanoparticles,has been attributed to the decrease in recombination rate of photo-generated electron—hole pairs.In the case of UV—visible reflectance spectra,the absorption edge for CaCO_3/TiO_2 nanoparticles has slightly been found to be blue-shifted as compared to bare TiO_2 nanoparticles,which corresponds to an increase in energy band gap of the former.The dye desorption studies reveal that CaCO_3/TiO_2 electrodes adsorbed more dye than the bare TiO_2 electrode.CaCO_3/TiO_2 based DSSC show improved photoelectrochemical properties compared to the bare TiO_2 based DSSC as CaCO_3 coating on TiO_2 forms an energy barrier,and,consequently suppressing the charge recombination,and,thus,improving the overall energy conversion efficiency(η) from 0.46%to 1.44%under the illumination of simulated light of 100 mW/cm~2.     

Principles Giving High Penetration under the Double Shielded TIG Process

A new welding method named double shielded tungsten inert gas(TIG) has been developed to improve the TIG weld penetration.The main principles to increase the weld depth have been discussed.Results show that the critical oxygen content in the weld pool is around 100 × 10~(-6) as the temperature coefficient of surface tension changes from negative to positive.The tracer test using pure silver shows that the direction of Marangoni convection changes as the oxygen content increases in the weld pool.The effect of arc constriction on the weld depth has been evaluated on a water-cooled copper plate,and the result indicates that the torch of double shielded can give a more powerful arc.Heavy oxide on the pool surface has undesirable impacts on the increasing of weld depth as the oxygen excessively accumulates in weld pool.It is possible to form chromium oxide in the weld process,while the iron oxide may form as the weld surface exposes to the air after the shielded gas moving away.     

CTAB Assisted Synthesis of CuS Microcrystals： Synthesis,Mechanism, and Electrical Properties

CuS microcrystals were successfully prepared through a mild solvothermal reaction in ethylene glycol （EG） with the assistance of cationic surfactant cetyltrimethylammonium bromide （CTAB）. An interesting morphology evolution from flower-like microspheres to hollow microspheres, and finally to smooth nanoflakes was observed when increasing the amount of CTAB. The products were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and UV-vis spectroscopy. It was found that the amount of CTAB played an important role in determining the morphology of the CuS microcrystals. Electrical measurement reveals that the as-prepared CuS microspheres were of high conductivity, which might favor their device applications. It is expected that CuS microcrystals with controlled morphologies and structures will have important applications in solar cells. This simple but effective method could also be extended to the controlled growth of other inorganic microcrystals.     

Effects of Pressure during Preparation on the Grain Orientation of Ruddlesden--Popper Structured BaLa2Ti3O10 Ceramic

As potential thermal barrier coating （TBC） materials, Ruddlesden-Popper structured BaLn2Ti3010 （Ln = rare earth） compounds possess excellent phase stability and desirable thermo-physical properties as well as interesting anisotropic structure. In this paper, the effects of pressure during BaLa2Ti3010 （BLT） bulk preparation on the grain orientation were investigated. BLT grains exhibited lamellar structure, but the grain orientation depended strongly on the existence of pressure during bulk preparation. When pressure was applied, BLT grains preferentially grew along pressing direction, leading to formation of the texture parallel to pressing direction, but BLT grain orientation became relatively random when pressure was absent. However, in the small scale area, BLT grains grew preferentially along c-axis with independence on pressure during preparation. Pressure affected BLT grain orientation at the rapid growth stage according to the grain growth model of BLT.     

1, 4-Bis （2-nitrobenzylidene） thiosemicarbazide as Effective Corrosion Inhibitor for Mild Steel

The inhibition efficiency of 1,4-bis （2-nitrobenzylidene） thiosemicarbazide （BBTS） on the corrosion of mild steel in 1 mol/L HCI was investigated by potentiodynamic polarization and electrochemical impedance methods. Inhibition efficiency （IE）, corrosion rate and surface coverage were evaluated at different concentrations of BBTS. The results of the investigation showed that this compound had good inhibiting properties for mild steel corrosion in hydrochloric acid and BBTS was a mixed-type inhibitor. BBTS chemisorbed at the electrode surface obeyed Langmuir adsorption isotherm and formed a stable surface complex on the mild steel surface. The synergistic effect of halide ion in acid solution suggested a co-adsorption of BBTS inhibitor by the adsorbed iodide ion.     

Influence of Substrate Temperature on Stress and Morphology Characteristics of Co Doped ZnO Films Prepared by Laser-Molecular Beam Epitaxy

Znl_xCoxO （x = 0.05） thin films are deposited on sapphire （0001） substrates by laser-molecular beam epitaxy technique at different substrate temperatures. The structural, stress and morphology evolution features are investigated by means of X-ray diffraction and atomic force microscopy. The surface parameters of roughness exponent α, root mean square （RMS） roughness w and autocorrelation length ~ are calculated and the surface parameters are preliminarily analyzed. The values of ~ vary from 0.7 to 0.9. The RMS roughness w is less than 2.2 nm, and it increases with increasing Ts from 300 to 400 °C, and then decreases when Ts is 500 °C. The autocorrelation length ~ decreases monotonously with the increase in Ts from 300 to 500 °C, which indicates that the increase in Ts restrains the spread of the surface fluctuations until Ts is higher than 400 °C.     

Photoelectrochemical behaviour of Cdln2S4 films deposited by pulse electrodeposition using non-aqueous electrolyte

Cdln2S4 films were deposited by the pulse electrodeposition technique on tin oxide-coated glass substrates, at different duty cycles in the range of 6%-50%. The deposition potential was -0.7 V vs, saturated calomel electrode （SCE） using non-aqueous di（ethylene glycol） electrolyte, XRD analysis of the films indicated polycrystalline nature. Grain size, strain and dislocation density were evaluated from the XRD data, EDX analysis of the surface composition confirms the formation of stoichiometric Cdln2S4 films, Optical studies show a direct band-gap values in the range of 2.14-2.23 eV for the films deposited at different duty cycles. Room temperature resistivity of the films was in the range of 40-21 Q.cm with the increase of duty cycle. Photoelectrochemical （PEC） solar cells constructed with the films deposited at 50% duty cycle and post-heat-treated at 500~C indicated open circuit voltage （Voc） of 0.595 V, short circuit current density （Jsc） of 6.20 mA.cm-2, fill factor （if） of 0.61, efficiency （t/） of 3.75%, series resistance （Rs） of 4Q and shunt resistance （Rsh） of 2.50kQ. Making use of the advantages of pulse electrodeposition it can be used to deposit nanocrystalline films which can be employed in optoelectronic and photovoltaic devices.     

The effect of calcination temperature on the capacitive properties of WO3-based electrochemical capacitors synthesized via a sol-gel method

Electrochemical capacitor （EC） is a promising energy storage device which can be hybridized with other energy conversion or energy storage devices. One type of ECs is pseudocapacitor made of metal oxides. WO3 is an inexpensive semiconductor metal oxide which has many applications. However the application of WO3 as an EC material was rarely reported. Therefore in this research EC was prepared from WO3 nanomaterial synthesized by a sol-gel process. The WO3 gel was spin-coated on graphite substrates and calcined at various temperatures of 300~C, 400℃, 500℃ and 600℃ for 1 h. Cyclic voltammetry （CV） measurements were used to observe the capacitive property of the WO3 samples. SEM, XRD, FTIR and Brunauer-Emmett-Teller （BET） analyses were used to characterize the material structures. WO3 calcined at 400~C was proved to have the highest capacitance of 233.63 Fo g^-1 （1869 mFo cm-2） at a scan rate of 2 mVo s-1 in 1 mol/L H2SO4 between potentials -0.4 and 0.4 V vs. SCE. Moreover it also showed the most symmetric CV curves as the indication of a good EC. Hence WO3 calcined at 400℃ is a potential candidate for EC material of pseudocapacitor type.     

Thermal Expansion of Al Matrix Composites Reinforced with Hybrid Micro-Aiano-sized Ai2O3 Particles简

The thermal expansion behavior of aluminum matrix composites reinforced with hybrid （nanometer and micrometer） Al2O3 particles was measured between 100 and 600℃ and compared to theoretical models. The results revealed that the nanoparticle concentration had significant effect on the thermal expansion behavior of the composites. For the composites with lower nanoparticle concentration, their coefficient of thermal expansion （CTE） is determined by a stress relaxation process. While for the composites with higher nanoparticle concentration, their CTE is determined by a percolation process.     

Solid State Reaction Preparation of LiFePO4/（C ＋ Cu） Cathode Material and Its Electrochemical Performance

Cu-C co-coated LiFePO4 （LiFePO4/（C ＋ Cu）） cathode material was successfully prepared through solid state reduction reaction. The optimized additive amount of CuO was determined by electrochemical test of series content-dependent samples. Electrochemical performances of LiFePO4/（C ＋ Cu） cathode material were investigated. Crystalline structure, morphology and electrochemical performance of the samples were characterized by X-ray diffraction, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, energy dispersive spectroscopy （EDS）, charge-discharge tests and AC impedance techniques. Results showed that crystal structure of the bulk material was not destroyed after Cu particles distributed on the surface of LiFePO4/C. With 5 wt% CuO additive, the LiFePO4/（C ＋ Cu） cathode material showed improved electrochemical performance especially at high rates and low temperature. At 25 ℃ and 0.1 C current rate, specific capacity of the Cu-coated sample reaches 161.3 mA h/g. The result was 47 mA h/g higher than that of the un-coated one. At -20 ℃, the discharge capacity of Cu-coated materials was 113.4 mA h/g at 0.1 C rate and 83.8 mA h/g at 5 C rate, which reached about 70% of that at room temperature, respectively.     

Type Inversion and Certain Physical Properties of Spray Pyrolysed SnO::A1Films for Novel Transparent Electronics Applications

Aluminium doped tin oxide films have been deposited onto glass substrates by using a simplified and low cost spray pyrolysis technique.The Al doping level varies between 0 and 30 at.%in the step of 5 at.%.The resistivity(ρ) is the minimum(0.38 Ω cm) for 20 at.%of Al doping.The possible mechanism behind the phenomenal zig-zag variation in resistivity with respect to Al doping is discussed in detail.The nature of conductivity changes from n-type to p-type when the Al doping level is 10 at.%.The results show that20 at.%is the optimum doping level for good quality p-type SnO_2:AI films suitable for transparent electronic devices.     

Effect of Hydrodynamic Conditions on Corrosion Inhibition of Cu-Ni (90/10) Alloy in Seawater and Sulphide Containing Seawater Using 1,2,3-Benzotriazole简

Electrochemical studies of the effect of hydrodynamic conditions on corrosion inhibition of Cu—Ni(90/10) alloy in synthetic seawater and sulphide containing synthetic seawater by 1,2,3-benzotriazole(BTAH) are presented.Impedance,potentiodynamic polarization and cyclic voltammetric(CV) studies are employed in the present investigation.The studies are carried out by using Cu—Ni(90/10) alloy rotating disc electrode at different rotation speeds and at different immersion periods.Reynolds numbers at each rotation speed infer that the flow of seawater is laminar.With increasing rotation speed of the electrode immersed in seawater without sulphide and BTAH,both the charge transfer resistance(R_(ct)) and film resistance(R_(film)) are increased.However,in the presence of sulphide ions and without BTAH,both the R_(ct) and R_(film) are found to decrease with increasing rotation speed at identical immersion periods.Interestingly,when BTAH is added to seawater or seawater containing sulphide,both the R_(ct) and R_(film) are increased to such a great extent that an inhibition efficiency of 99.99%is obtained.In the presence of BTAH,the phase angle Bode plots are more broadened and the maximum values of phase angle are increased to a value close to 90° as the rotation speed is increased.The BTAH film is highly protective even under hydrodynamic condition also.Potentiodynamic polarization studies infer that BTAH functions as a mixed inhibitor under hydrodynamic conditions also.CV studies reveal that the protective BTAH film is stable even at anodic potentials of +850 mV vs Ag/AgCI.     

Enhanced Stability of Anisotropic Gold Nanoparticles by Poly（N-isopropylacrylamide）

A simple synthetic method has been described to prepare anisotropic gold nanoparticles （AuNPs） possessing unique optical and structural properties at room temperature, and subsequently the nanoparticles have been stabilized by temperature-sensitive poly（N-isopropylacrylamide）, or poly（NIPAM）. Although poly（NIPAM） does not exhibit a strong binding affinity to gold, simply introducing poly（NIPAM） to these unstable anisotropic AuNPs can maintain the original structures and absorption properties for several weeks. This increased stability is presumably caused by the adsorbed polymer layer around the anisotropic AuNPs. The existence of adsorbed linear poly（NIPAM） around the AuNPs is confirmed through the reversible absorption properties of the nanoparticles upon heating and cooling. To verify the presence of weak attractive forces （e.g., van der Waals, dipole-dipole, and possible hydrogen bonding） between the polymer and the AuNPs, various concentrations of linear poly（NIPAM） are introduced during the formation of the AuNPs resulting in the systematical control of the size and roughness of the nanoparticles. In addition, the preferential attachment of pre-formed anisotropic AuNPs on cross-linked poly（NIPAM） nanoparticles indicates the presence of weak attractive forces between AuNPs and poly（NIPAM）. As such, poly（NIPAM） and its derivatives can serve as a useful stabilizing and capping agent to preserve the properties of the anisotropic AuNPs.     

Microstructural Evolution of a Ni-base Alloy DZ468 Joint Bonded with a New Co-base Filler

Ni-base alloy DZ468 has been joined by transient liquid phase bonding technique with a newly developed Co-based filler. The microstructures of the Co-base filler and the joint, the effects of heat treatment on microstructure and hardness of the joint have been investigated by various experimental methods. Results show that the Co-base filler consists of γ, M2B, M5B3 and M23B6 phases. Because of the interdiffusion between the base metal and the filler, γ, MC, M5B3 and M23B6 phases are formed in the bonding zone. And localized liquidation of substrate occurs in the diffusion affected zone, with MC and M3B2 precipitating in this area. During heat treatment, the volume of the intermetallic phases in the bonding zone resulting from incomplete isothermal solidification decreases obviously. On the contrary, the width of the diffusion affected zone increases at the solution stage and subsequently decreases at the aging stages.     

Crystallographic Analysis of Isothermally Transformed Bainite in 0.2C-2.0Mn-1.55Si-0.6Cr Steel Using EBSD

The crystallography of bainite,transformed isothermally at 450℃in 0.2C-2.0Mn-1.5Si-0.6Cr steel,was investigated by electron backscatter diffraction(EBSD) analysis.The orientation relationship(OR) was found to be closer to Ntshiyama-Wassermann(N-W) than Kurdjumov—Sachs orientation relationship.Bainite microstructure consisted of parallel laths forming a morphological packet structure.Typically,there were three different lath orientations in a morphological packet.These orientations were dictated by a three specific N—W OR variants sharing the same {111} austenite plane.A packet of bainite laths with common {111} austenite plane was termed as crystallographic packet.Generally,the crystallographic packet size corresponded to the morphological packet size.Locally,crystallographic packets with only two dominant orientations were observed.This indicates strong local variant selection during isothermal bainite transformation.The relative orientation between the variants in crystallographic packets was found to be near 60°/<110>.This appears to explain the strong peak observed in the grain boundary misorientation distribution near 60°.Bainite also contained pronounced fraction of boundaries with their misorientation in the range of 2.5°—8°with quite widely dispersed rotation angles.Spatially these boundaries were found to locate inside the bainite laths,forming lath-like sub-grains.     

Resource-constrained Project Scheduling with Overlapping Activities Based on Extended Dependency Structure Matrix

Dependency Structure Matrix （DSM） is a successful and powerful tool for representing and analyzing dependencies between the items, but for external influencing factors it cannot charge effectively. This paper sets the stage for connecting the activities and resources, which not only considers information flow but also resources constrains.We first introduce the DSM to represent the degree of overlapping between the activities in a project. Then we present the Extended DSM combined former DSM and resource factors to calculate the project duration. Finally, the practical significance of the Extended DSM is confirmed by an illustrative example.     

Formation and Dissociation of Bamboo-like ErD2/ErD3 Grains

The formation and dissociation of Er deuteride grains were investigated by using scanning electron microscopy, in-situ X-ray diffraction and thermal desorption spectroscopy. Pure Er film shows classic columnar structure, while the Er deuteride film was observed as bamboo-like morphology. The in-situ X-ray diffraction results demonstrate that the diffraction peaks of 27.39°, 28.43°, 31.71°, and 39.95° are ascribed to the crystal planes of （002）, （110）, （111）, and （112） of ErD3 phase, respectively. It is also confirmed that by in-situ X-ray diffraction technique, ErD3 grains would be dissociated at temperature exceeding 400 ℃. This result is consistent with the conclusion obtained by thermal desorption spectroscopy.     

Effect of Sn precursor on the synthesis of SnO2 and Sb-doped SnO2 particles via polymeric precursor method

SnO2 and Sb-doped SnO2 particles were synthesized using the polymeric precursor method with different Sn salt precursors： SnCl2.2H2O, SnCl4.5H20, or Sn citrate. Sb2O3 was used as the precursor of Sb, and the molar ratio of nsn：nsb was held constant. FTIR and TGA/DTA were used to examine the influence of the Sn precursor on the formation and thermal decomposition of the Sn and Sn-Sb complexes. The calcination products obtained from heating the Sn and Sn-Sb complexes at 500℃ in air were analyzed using XRD and TEM analysis. The results revealed that the SnO2 and Sb-doped SnO2 formation temperatures depended on the nature of the Sn precursor. The calcination products were found to be SnO2 and Sb-doped SnO2 particles, which crystallized in a tetragonal cassiterite structure with a highly preferred （110） planar orientation. The Sn precursor and the presence of Sb in the SnO2 matrix strongly influenced the crystallinity and lattice parameters.