In vitro degradation of MAO/PLA coating on Mg-1.21Li-1.12Ca-1.0Y alloy

Magnesium and its alloys are promising biomaterials due to their biocompatibility and osteoinduction. The plasticity and corrosion resistance of commercial magnesium alloys cannot meet the requirements for degradable biomaterials completely at present. Particularly, the alkalinity in the microenvironment surrounding the degradation, implants, resulting from the arises a major concern. Micro arc oxidation （MAO） and poly（lactic acid） （PLA） composite （MAO/PLA）coating on biomedical Mg- 1.21Li-1.12Ca-1.0Y alloy was prepared to manipulate pH variation in an appropriate range. Surface morphologies were discerned using SEM EMPA. AM corrosion resistance was evaluated via electrochemical Polarization and impedance and hydrogen volumetric method. The results demonstrated that the MAO coating predomlnantly consisted of MgO, Mg2SiO4 and YzO3. The composite coating markedly improved the corrosion resistance of the alloy. The rise in solution pH for the MAO/PLA coating was tailored to a favorable range of 7.5-7.8 The neutrallzation caused by the alkalinity of MAO and Mg substrate and acidification of PLA was probed. The reSult designates that MAOI PLA composite coating on Mg-1.21Li-1.12Ca-1.0Y alloys may be a promising biomedical coating.     

Origin of high mechanical quality factor in CuO-doped （K,Na）NbO3-based ceramics

The origin of a high mechanical quality in CuO-doped （K, Na）NbO3-based ceramics is addressed by considering the correlations between the lattice positions of Cu ions and the hardening effect in K0.48Na0.52＋xNbO3-0.01CuO ceramics. The Cu ions simultaneously occupy K/Na and Nb sites of these ceramics with x = 0 and 0.02, only occupy the K/Na site of the ceramics with x= -0.02, and mostly form a secondary phase of the ceramics with x = -0.05. The Cu ions lead to the hardening of ceramics with an increase of Ec and Qm by only occupying the K/Na site, together with the formation of double hysteresis loops in un-poled compositions. A defect model is proposed to illuminate the origin of a high Qm value, that is, the domain stabilization is dominated by the content of relatively mobile O2- ions in the ceramics, which has a weak bonding with CUK/Na defects.     

Modifying the Properties of Tungsten Based Plasma Facing Materials with Single-Wall Carbon Nanotubes

Tungsten is one of the best candidates for plasma-facing components in fusion reactors owing to its unique properties. But disadvantages such as its brittleness and high ductile-to-brittle transition temperature have restricted its fusion energy application. Single-walled carbon nanotubes （SWCNTs） have the potential to be used as reinforcements due to their excellent mechanical properties. A new method of modifying the properties of tungsten by doping with SWCNTs was introduced. An efficient way of dispersing SWCNTs into the tungsten matrix with strong interfaces by heterocoagulation and ultrasonication was employed, and hot explosive compaction （HEC） technology was selected to compact and sinter the composite powders. The sintering properties, microstructure, densification effect, thermal conductivity, hardness and fracture toughness of the obtained SWCNTs/W bulk samples were tested, and compared with pure tungsten. The influences of SWCNTs on these properties and the main toughening mechanism of SWCNTs in a tungsten matrix were discussed.     

Enhanced photodynamic therapy of mixed phase TiO2（B）/anatase nanofibers for killing of HeLa cells

Photodynamic therapy （PDT）, which is a procedure that uses photosensitizing drug to apply therapy selectively to target sites, has been proven to be a safe treatment for cancers and conditions that may develop into cancers. Nano-sized TiO2 has been regarded as potential photosensitizer for UV light driven PDT. In this study, four types of TiO2 nanofibers were prepared from proton tri-titanate （H2T3O7） nanofiber. The as-obtained nanofibers were demonstrated as efficient photosensitizers for PDT killing of HeLa cells. MTT assay and flow cytometry （FCM） were carried out to evaluate the biocompatibility, percentage of apoptotic cells, and cell viability. The non-cytotoxicity of the as-prepared TiO2 nanofibers in the absence of UV irradiation has also been demonstrated. Under UV light irradiation, the TiO2 nanofibers, particularly the mixed phase nanofibers, displayed much higher cell-killing efficiency than Pirarubicin （THP）, which is a common drug to induce the apoptosis of HeLa cells. We ascribe the high cell- killing efficiency of the mixed phase nanofibers to the bandgap edge match and stable interface between TiO2（B） and anatase phases in a single nanofiber, which can inhibit the recombination of the photogenerated electrons and holes. This promotes the charge separation and transfer processes and can produce more reactive oxygen species （ROS） that are responsible for the killing of HeLa cells.     

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.     

Effect of Fe Content on the Interfacial Reliability of SnAgCu/Fe-Ni Solder Joints

Fe-Ni films with compositions of Fe-75Ni, Fe-50Ni, and Fe-30Ni were used as under bump metallization （UBM） to evaluate the interracial reliability of SnAgCu/Fe-Ni solder joints through ball shear test, high temperature storage, and temperature cycling. The shear strengths for Fe-75Ni, Fe-5ONi, and Fe-3ONi solder joints after reflow were 42.57, 53.94 and 53.98 MPa, respectively, which were all satisfied the requirement of industrialization （〉34.3 MPa）. High temperature storage was conducted at 150, 175 and 200 ℃. It was found that higher Fe content in Fe-Ni layer had the ability to inhibit the mutual diffusion at interface region below 150 ℃, and the growth speed of intermetallic compound （IMC） decreased with increasing Fe concentration. When stored at 200 ℃, the IMC thickness reached a limit for all three films after 4 days, and some cracks occurred at the interface between IMC and Fe-Ni layer. The activation energies for the growth of FeSn2 on Fe-30Ni, Fe-5ONi, and Fe-75Ni films were calculated as 246, 185, and 81 kJ/mol, respectively. Temperature cycling tests revealed that SnAgCu/Fe-5ONi solder joint had the lowest failure rate （less than 10%）, and had the best interfacial reliability among three compositions.     

Study of photocurrent generation in InP nanowire-based p＋-i-n＋ photodetectors

We report on electrical and optical properties of p＋-i-n＋ photodetectors/solar cells based on square millimeter arrays of InP nanowires （NWs） grown on InP substrates. The study includes a sample series where the p＋-segment length was varied between 0 and 250 nm, as well as solar cells with 9.3% efficiency with similar design. The electrical data for all devices display clear rectifying behavior with an ideality factor between 1.8 and 2.5 at 300 K. From spectrally resolved photocurrent measurements, we conclude that the photocurrent generation process depends strongly on the p~-segment length. Without a p＋-segment, photogenerated carriers funneled from the substrate into the NWs contribute strongly to the photocurrent. Adding a p＋-segment decouples the substrate and shifts the depletion region, and collection of photogenerated carriers, to the NWs, in agreement with theoretical modeling. In optimized solar cells, clear spectral signatures of interband transitions in the zinc blende and wurtzite InP layers of the mixed-phase i-segments are observed. Complementary electroluminescence, transmission electron microscopy （TEM）, as well as measurements of the dependence of the photocurrent on angle of incidence and polarization, support our interpretations.     

Ageing mechanisms and reliability of graphene-based electrodes

The development of flexible transparent electrodes for next generation devices has been appointed as the major topic in carbon electronics research for the next five years. Among all candidate materials tested to date, graphene and graphene based nanocomposites have shown the highest performance. Although some incipient anti-oxidation tests have been reported, in-deep ageing studies to assess the reliability of carbon-based electrodes have never been performed before. In this work, we present a disruptive methodology to assess the ageing mechanisms of graphene electrodes, which is also extensible to other carbon- based and two-dimensional materials. After performing accelerated oxidative tests, we exhaustively analyze the yield of the electrodes combining nanoscale and device level experiments with Weibull probabilistic analyses and tunneling current simulation, based on the Fowler-Nordheim/Direct-Tunneling models. Our experiments and calculations reveal that an ultra-thin oxide layer can be formed on the pristine surface of graphene. We quantitatively analyze the consequences of this layer on the properties of the electrodes, and observed a change in the conduction mode at the interface （from Ohmic to Schottky）, an effect that should be considered in the design of future graphene-based devices. Future mass production of carbon-based devices should include similar reliability studies, and the methodologies presented here （including the accelerated tests, characterization and modeling） may help other scientists to move from lab prototypes towards industrial device production.     

水泥行业能源管理体系标准进展及实施探索(英文)简

The energy-saving management of China＇ s cement industry has gradually improved in recent years; however, cement industry still faces big pressure of facilitating energy conservation and emission reduction. Based on the current development of cement industry, the paper summarizes and analyzes the application and promotion of energy management system （EnMS） standardization in cement industry, then gives a brief introduction to the implementation of related standards and at last explores the positive function of energy management system in enhancing enterprises＇ energy management and improving energy performance.     

Structure and quality controlled growth of InAs nanowires through catalyst engineering

In this study, the structure and quality controlled growth of InAs nanowires using Au catalysts in a molecular beam epitaxy reactor is presented. By tuning the indium concentration in the catalyst, defect-free wurtzite structure and defect-free zinc blende structure InAs nanowires can be induced. It is found that these defect-free zinc blende structure InAs nanowires grow along 〈110〉 directions with four low-energy {111} and two {110} side-wall facets and adopt the （111） catalyst/nanowire interface. Our structural and chemical characterization and calculations identify the existence of a catalyst supersaturation threshold for the InAs nanowire growth. When the In concentration in the catalyst is sufficiently high, defect-free zinc blende structure InAs nanowires can be induced. This study provides an insight into the manipulation of crystal structure and structure quality of III-V semiconductor nanowires through catalyst engineering.     

Construction and Characterization of an Ultrasonic Array Using Different Backing Materials to Evaluate Crosstalk

The construction and characterization of an ultrasonic array using different backing materials are presented. In the construction of these arrays PZT piezoelectric elements are used as sensors. The objective of this paper is to evaluate the propagation of crosstalk in different materials to find an optimum material to be used in the construction of the array. Rexolite, copper and brass were the materials used in this work due to their ideal propagation characteristics and taking into account the geometry and dimensions of the array, these three different materials were studied to verify which one of them offered the best option to determine the propagation of the phenomenon of crosstalk. Simulations made using a finite elements software （COMSOL） showed that the various modes of response of the array can be determined, and using frequency generators, drivers and digital oscilloscopes is possible to validate the simulations presented in this work.     

Direct vapor phase growth process and robust photoluminescence properties of large area MoS2 layers

There has been growing research interest in the use of molybdenum disulfide in the fields of optoelectronics and energy harvesting devices, by virtue of its indirect-to-direct band gap tunability. However, obtaining large area thin films of MoS2 for future device applications still remains a challenge. In the present study, the amounts of the precursors （S and MOO3） were varied systematically in order to optimize the growth of highly crystalline and large area MoS2 layers by the chemical vapor deposition method. Careful control of the amounts of precursors was found to the key factor in the synthesis of large area highly crystalline flakes. The thickness of the layers was confirmed by Raman spectroscopy and atomic force microscopy. The optical properties and chemical composition were studied by photoluminescence （PL） and X-ray photoelectron spectroscopy. The emergence of strong direct excitonic emissions at 1.82 eV （A-exciton, with a normalized PL intensity of -55 × 10^3） and 1.98 eV （B-exciton, with a normalized PL intensity of -5 × 10^3） of the sample at room temperature clearly indicates the high luminescence quantum efficiency. The mobility of the films was found to be 0.09 cm^2/（V.s） at room temperature. This study provides a method for the controlled synthesis of high-quality two-dimensional （2D） transition metal dichalcogenide materials, useful for applications in nanodevices, optoelectronics and solar energv conversion.     

On-chip detection of a single nucleotide polymorphism without polymerase amplification

A nanoparticle-assembled photonic crystal （PC） array was used to detect single nucleotide polymorphism （SNP）. The assay platform with PC nanostructure enhanced the fluorescent signal from nanoparticle-hybridized DNA complexes due to phase matching of excitation and emission. Nanoparticles coupled with probe DNA were trapped into nanowells in an array by using an electrophoretic particle entrapment system. The PC/DNA assay platform was able to identify a 1 base pair （bp） difference in synthesized nucleotide sequences that mimicked the mutation seen in a feline model of human autosomal dominant polycystic kidney disease （PKD） with a sensitivity of 0.9 fg/mL （50 aM）-sensitivity, which corresponds to 30 oligos/array. The reliability of the PC/DNA assay platform to detect SNP in a real sample was demonstrated by using genomic DNA （gDNA） extracted from the urine and blood of two PKD-wild type and three PKD positive cats. The standard curves for PKD positive （PKD＋） and negative （PKD-） DNA were created using two feline-urine samples. An additional three urine samples were analyzed in a similar fashion and showed satisfactory agreement with the standard curve, confirming the presence of the mutation in affected urine. The limit of detection （LOD） was 0.005 ng/mL which corresponds to 6 fg per array for gDNA in urine and blood. The PC system demonstrated the ability to detect a number of genome equivalents for the PKD SNP that was very similar to the results reported with real time polymerase chain reaction （PCR）. The favorable comparison with quantitative PCR suggests that the PC technology may find application well beyond the detection of the PKD SNP, into areas where a simple, cheap and portable nucleic acid analvsis is desirable.     

A modified spontaneous emulsification solvent diffusion method for the preparation of curcumin-loaded PLGA nanoparticles with enhanced in vitro anti-tumor activity

To improve the anti-tumor activity of hydrophobic drug curcumin, we prepared curcumin-loaded PLGA nanoparticles （PLGA-Cur NPs） through a modified spontaneous emulsification solvent diffusion （modified-SESD） method. The influence of main preparation parameters was investigated, such as the volume ratio of binary organic solvents and the concentration of surfactant. Results indicated that the synthesized regular spherical PLGA NPs with the average diameter of 189.7 nm exhibited relatively higher yield （58.9%）, drug loading （11.0% （w/w）） and encapsulation efficiency （33.5%）, and also a controllable drug release profile. In order to evaluate the in vitro cytotoxicity of the prepared NPs, MTT assay was conducted, and results showed that the NPs could effectively inhibit HL60 and HepG2 cells with lower IC50 values compared with free curcumin. Furthermore, confocal microscopy together with flow cytometry analysis proved the enhanced apoptosis-inducing ability of PLGA-Cur NPs. Polymeric NP formulations are potential to be used for hydrophobic drug delivery systems in cancer therapy.     

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.     

Functionally Graded Dual-nanoparticulate-reinforced Aluminium Matrix Bulk Materials Fabricated by Spark Plasma Sintering

Functionally graded（FG） carbon nanotubes（CNT） and nano-silicon carbide（nSiC） reinforced aluminium（Al）matrix composites have been successfully fabricated using high-energy ball milling followed by solid-state spark plasma sintering processes.The CNTs were well-dispersed in the Al particles using the nSiC as a solid mixing agent.Two different types of multi-walled CNTs were used to add different amounts of CNTs in the same volume.The ball milled Al—CNT—nSiC and Al—CNT powder mixtures were fully densified and demonstrated good adhesion with no serious microcracks and pores within an FG multilayer composite.Each layer contained different amounts of the CNTs,and the nSiC additions showed different microstructures and hardness.It is possible to control the characteristics of the FG multilayer composite through the efficient design of an Al—CNT—nSiC gradient layer.This concept offers a feasible approach for fabricating the dualnanoparticulate-reinforced Al matrix nanocomposites and can be applied to other scenarios such as polymer and ceramic systems.     

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.     

Two-dimensional semiconductors with possible high room temperature mobility

We have calculated the longitudinal acoustic phonon limited electron mobility of 14 twvo-dimensional semiconductors with composition of MX2, where M （= Mo, W, Sn, Hf, Zr and Pt） is the transition metal, and X is S, Se and Te. We treated the scattering matrix by the deformation potential approximation. We found that out of 14 compounds, MoTe2, HfSe2 and ZrSe2 are promising regarding to their possible high mobility and finite band gap. The phonon limited mobility can be above 2,500 cm^2·V^-1·s^-1 at room temperature.     

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.     

Structural Morphological and Optical Properties of SnSb2S4 Thin Films Grown by Vacuum Evaporation Method

SnSb2S4 thin films were prepared from powder by thermal evaporation under vacuum of 1.33 × 10^-4 Pa （ 10^-6 Torr） on unheated glass substrates. The effect of thickness on the structural, morphological and optical properties of SnSb2S4 thin films was investigated. Films thickness measured by interference fringes method varied from 50 to 700 nm. X-ray diffraction analysis revealed that all the SnSb2S4 films were polycrystalline in spite without heating the substrates and the crystallinity was improved with increasing film thickness. The microstructure parameters： crystallite size, strain and dislocation density were calculated. It was observed that the crystallite size increased and the crystal defects decreased with increasing film thickness. In addition, by increasing the film thickness, an enhancement in the surface roughness root-mean-square （RMS） increased from 2.0 to 6.6 nm. The fundamental optical parameters like band gap, absorption and extinction coefficient were calculated in the strong absorption region of transmittance and reflectance spectrum. The optical absorption measurements indicated that the band （Eg） gap of the thin films decreased from 2.10 to 1.65 eV with increasing film thickness. The refractive indexes were evaluated in transparent region in terms of envelope method, which was suggested by Swanepoul. It was observed that the refractive index increased with increasing film thickness.