In order to improve the gaseous and electrochemical hydrogen storage kinetics of the Mg₂Nitype alloy, the elements Cu and Nd were added in the alloy. The nanocrystalline and amorphous Mg₂Ni-type alloys with the composition of (Mg₂₄Ni₁₀Cu₂)_100-xNd _x (x = 0, 5, 10, 15, 20) were prepared by melt spinning technology. The effects of Nd content on the structures and hydrogen storage kinetics of the alloys were investigated. The characterization by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) reveals that all the as-cast alloys hold multiphase structures, containing Mg₂Ni-type major phase as well as some secondary phases Mg₆Ni, Nd₅Mg₄₁, and NdNi, whose amounts clearly grow with increasing Nd content. Furthermore, the as-spun Nd-free alloy displays an entire nanocrystalline structure, whereas the as-spun Nd-added alloys hold a mixed structure of nanocrystalline and amorphous structure and the amorphization degree of the alloys visibly increases with the rising of the Nd content, suggesting that the addition of Nd facilitates the glass forming in the Mg₂Ni-type alloy. The measurement of the hydrogen storage kinetics indicates that the addition of Nd significantly improves the gaseous and electrochemical hydrogen storage kinetics of the alloys. The addition of Nd enhances the diffusion ability of hydrogen atoms in the alloy, but it impairs the charge-transfer reaction on the surface of the alloy electrode, which makes the high rate discharge ability (HRD) of the alloy electrode first mount up and then go down with the growing of Nd content.

Perfluorosulfonic acid/ceramic nanocomposite membranes were investigated as electrolytes for polymer electrolyte membrane fuel cell applications under low relative humidity. Different nanosized ceramics (SiO₂, ZrO₂, TiO₂) with diameters in the range of 2-6 nm were synthesized in situ in Nafion solution through a sol-gel process and the formed nanosized ceramics were well-dispersed in the solution. The nanocomposite membranes were formed through a casting process. The nanocomposite membrane showes enhanced water retention ability and improved proton conductivity compared to those of pure Nafion membrane. The mechanical strength of the formed nanocomposite membranes is slightly less than that of pure Nafion membrane. The experimental results demonstrate that the polymer ceramic nanocompsite membranes are potential electrolyte for fuel cells operating at elevated temperature.

The magnetization of Hg_0.89Mn_0.11Te single crystal grown by vertical Bridgman method was studied by using superconducting quantum interference device magnetometer (SQUID Magnetometer). First, magnetization measurements were done under various magnetic field strengths from -20 kOe to 20 kOe at 5 K, 15 K, and 77 K, respectively. Then, the magnetizations were measured with continuous changes of temperature in the range from 5 K to 300 K under the magnetic field of 0.1 kOe and 10 kOe, respectively. The modified Brillouin function was well fitted with the data of magnetization vs. magnetic field strength. The analysis indicated that there was an antiferromagnetic exchange coupling among Mn²⁺ ions. The results of reciprocal susceptibility vs. temperature fit Curie-Weiss law very well at the temperatures above 40 K, but deviate from the law from 5 K to 40 K, which shows that the antiferromagnetic exchange coupling among Mn²⁺ ions increases in the lower temperature range below 40 K. The experimental result was explained by extending higher-order terms in the calculation of susceptibility and fitted by a power law function. The measurements reveal that Hg_0.89Mn_0.11Te possesses paramagnetic properties at temperatures from 5 K to 300 K.

We comprehensively study the co-precipitation preparation of aluminum doped zinc oxide (AZO) nanoparticles, ceramic target and thin film deposition. The When the calcination temperature exceeded 700 °C, ZnAl₂O₄ phase appeared. The resistivity and relative density of the AZO target pressed from nanoparticles were 3×10^-3 Ω∙cm and 99.1%, respectively. The minimum resistivity of AZO thin films prepared by DC sputtering of the ceramic target reached 4.1×10^–4 Ω∙cm with the mobility of 33 cm²/v∙s and the carrier concentration of 4.5 ×10²⁰ cm^-3. The average optical transmittance of the AZO thin films in the visible wavelength range (400-800 nm) was more than 80%.

The aim of this work was to investigate the size-related magnetism for the single-domain CoFe₂O₄ nano-particles synthesized using the hydrothermal method. The effects of the reaction temperature and the reaction time on the lattice constants, particle morphologies, and the room-temperature magnetic properties were studied from the X-ray diffraction, the transmission electron microscope, and the vibrating-sample magnetometer. The experimental results show that the samples are composed of CoFe₂O₄ nano-particles with an average crystallite size (D) smaller than 40 nm, and the magnetic properties of the samples can be manipulated in a wide range: the M _S values vary from smaller than 50 emu/g to close to 80 emu/g, and the H _C values are between about 200 Oe and 2000 Oe. Additionally, the relationship between H _C and 1/D ^3/2 satisfies linearship, showing the characteristic of single-domain structure. These results indicate that the single-domain CoFe₂O₄ nano-particles with size controlled between the superparamagnetic critical size and single-domain critical size can be easily prepared using this hydrothermal method.

Polyaniline nanotubes and PANI-ZnO nanocomposites were prepared by the simplified Template-Free method. The experimental results indicated that the average diameter of Polyaniline nanotubes was approximately 150-200 nm. The average crystallite size of ZnO in PANI-ZnO composites was 27 nm. Moreover, the as-prepared samples were characterized by scanning electron microscopy (SEM), FT-IR spectroscopy(FTIR) and X-ray diffraction (XRD). Photocatalytic properties of the obtained samples were investigated by the photodegradation analysis of orange II and methylene orange dye. The as-prepared PANIZnO nanocomposites exhibited much higher photocatalytic activity than pure PANI nanotubes. During 2 h photocatalytic courses under UV irradiation, the degradation ratios of Orange II and methyl orange using PANIZnO nanocomposites were 90.3% and 84.5%, respectively. Furthermore, this method can be extended to prepare other organic-inorganic semiconductor composites based composite catalysts.

A novel chemical technique combined with unique plasma activated sintering (PAS) was utilized to prepare consolidated copper matrix composites (CMCs) by adding Cu-SnO₂-rGO layered micro powders as reinforced fillers into Cu matrix. The repeating Cu-SnO₂-rGO structure was composed of inner dispersed reduced graphene oxide (rGO), SnO₂ as intermedia and outer Cu coating. SnO₂ was introduced to the surface of rGO sheets in order to prevent the graphene aggregation with SnO₂ serving as spacer and to provide enough active sites for subsequent Cu deposition. This process can guarantee rGO sheets to sufficiently disperse and Cu nanoparticles to tightly and uniformly anchor on each layer of rGO by means of the SnO₂ active sites as well as strictly control the reduction speed of Cu²⁺. The complete cover of Cu nanoparticles on rGO sheets thoroughly avoids direct contact among rGO layers. Hence, the repeating structure can simultaneously solve the wettability problem between rGO and Cu matrix as well as improve the bonding strength between rGO and Cu matrix at the well-bonded Cu-SnO₂-rGO interface. The isolated rGO can effectively hinder the glide of dislocation at Cu-rGO interface and support the applied loads. Finally, the compressive strength of CMCs was enhanced when the strengthening efficiency reached up to 41.

A resistance random access memory (RRAM) with a structure of Ag/ZnMn₂O₄/p-Si was fabricated by magnetron sputtering method. Reliable and repeated switching of the resistance of ZnMn₂O₄ films was obtained between two well-defined states of high and low resistance with a narrow dispersion and 3V switching voltages. Resistance ratio of the high resistance state and low resistance state was found in the range of around 10³ orders of magnitude and up to about 10³ test cycles. The retention time of Ag/ZnMn₂O₄/ p-Si device is longer than 10⁶ seconds and the resistance ratio between two states remains higher than 10³ at room temperature, showing a remarkable reliability performance of the RRAM devices for nonvolatile memory application. The equivalent simulation circuits for HRS (high resistance state) and LRS (low resistance state) were also studied by impedance spectroscopy.

Here, a new idea was proposed for template-free synthesis of hierarchical m-ZrO₂ nanorods and “their” possible formation mechanism based on a series of chemical reactions by simple hydrothermal method. The traditional preparation methods of hierarchical ZrO₂ nanorods involved inexpensive equipment, complicated process, and high production cost. The as-synthesized products composed of many nanorods with 180-200 nm in diameter and 5-7 μm in length. The final product after annealing involved hierarchical monoclinic ZrO₂ (m-ZrO₂) nanorods, namely, the big nanorod was made up of many small nanorods with 40-50 nm in diameter and 500-600 nm in length. The experimental results were useful in understanding the chemical properties of ZrB₂ and ZrO₂ and the design of the derivatives for m-ZrO₂ nanomaterials.

The influence law of clay on mortar fluidity mixed with polycarboxylate superplasticizer was studied. Several methods of inhibiting clay adsorption of polycarboxylate superplasticizer were discussed. The experimental results show that clay has significant effect on the dispersion of polycarboxylate superplasticizer and montmorillonite clay has more significant impact on mortar fluidity than other clays. The pH value and the salts of the solution can affect the adsorption of clay to polycarboxylate superplasticizer. The incorporation of a small amount of sodium hydroxide solution, sodium silicate or cationic surfactants can improve the effect of the clay on the dispersion of polycarboxylate superplasticizer.

Based on molecular mechanics and the deformation characteristics of the atomic lattice structure of graphene, a modified molecular structure mechanics method was developed to improve the original one, that is, the semi-rigid connections were used to model the bond angle variations between the C-C bonds in graphene. The simulated results show that the equivalent space frame model with semi-rigid connections for graphene proposed in this article is a simple, efficient, and accurate model to evaluate the equivalent elastic properties of graphene. Though the present computational model of the semi-rigid connected space frame is only applied to characterize the mechanical behaviors of the space lattices of graphene, it has more potential applications in the static and dynamic analyses of graphene and other nanomaterials.

TiO₂ was employed as the waste form for disposal of simulated nuclide Sr. Preparation of Sr bearing rutile was explored under different sintering temperatures and Sr contents. The optimal treatment temperature was confirmed as 1 300 °C for the incorporation of SrO in rutile TiO₂. Perovskite type SrTiO₃ was prepared as the resultant product. The limited containment capacity of SrO in rutile was speculated to be 56.5wt%. As the SrO content increases, the as-synthesized sample exhibits more porosity because SrTiO₃ phase demonstrates higher density than rutile and SrO. The 28 day normalized leaching rate (LRi) of Sr and Ti will decrease congruously as the SrO incorporation increases. The LR_Sr value is lower than 0.1 g·m^-2·d^-1, which is about 3 orders of magnitude higher than the LR_Ti value.

In order to reduce shrinkage and improve the mechanical properties of dental composite resins, we designed a hybrid resin formulation containing a novel matrix resin, BisS-GMA [bisphenol-Sbis( 3-methacrylato-2-hydroxypropyl)ether], and epoxy modified by a spiro-orthocarbonate (SOC) expanding monomer. Then, we tested the effects of an iodonium salt, diphenyliodonium hexafluorphosphate (DPIHFP), on the properties of the hybrid resin with seven different concentrations. The hybrid resin was polymerized by a ternary photo-initiator system. The volumetric shrinkage (VS), degree of conversion (DC) and compressive strength (CS) were assessed using AcuVol™, FTIR and a universal testing machine, respectively. The VS, DC and CS were improved with increasing DPIHFP concentration, but a high concentration of DPIHFP had a negative influence on the mechanical properties of the hybrid resin and offered no added improvement in the VS and DC. The best performance of a composite resin containing BisS-GMA and SOC-modified epoxy was achieved with 2wt% DPIHFP. The results also indicated that the resin containing BisS-GMA was superior to that containing Bis-GMA in terms of VS, DC and CS.

A water-conducting polyacrylamide/montmorillonite coating was prepared by solutionblending. The coating was coated on fiber and then composited with polymer to form a composite film material that used for water saving and tree planting in arid and desert regions. The coating’s water-conducting characteristics and dynamic self-adjusting behavior were investigated by Fourier transform infrared (FTIR) spectroscopy, thermal analysis (TG-DTA), and environmental scanning electron microscopy (ESEM).The results showed that the coating’s water-conducting rate increased but water-retention capacity weakened with increasing montmorillonite content. The water-loss rate was positively related to temperature and negatively related to soil moisture. Water potential greatly influenced the water-conducting rate of the coating during its water conduction process. When the coating was at a low water potential, the montmorillonite particles interconnected and water was conducted quickly via montmorillonite layers, whereas when the coating was at a high potential, the montmorillonite particles disconnected and water was conducted slowly via the swelled polyacrylamide net structure. The rate can be regulated by changing the proportion of polyacrylamide and montmorillonite to guarantee a reasonable water supply for trees and make trees easier to survive. Thus, the survival rate of trees can be increased and the use of water resources can be significantly reduced.

It was aim to investigate the interfacial microstructure and shear performance of Ti/Cu clad sheet produced by explosive welding and annealing. The experimental results demonstrate that the alternate distribution of interfacial collision and vortex of flyer layer forms in the interface a few of solidification structure. TEM confirms that the interfacial interlayer contains obvious lattice distortion structure and intermetallic compounds. It interprets the explosive welding as the interfacial deformation and thermal diffusion process between dissimilar metals. The interfacial shear strength is very close to the Cu matrix strength, which is determined by the mixture of the mechanical bonding and metallurgical bonding. Several cracks exist on the shear fracture owing to the intermetallic compound in the interfacial solidification structure and also the probable welding inclusion.

A series of V₂O₅ with various morphologies was prepared by the hydrothermal method and loaded on the modified active coke (AC) which was prepared by the impregnation methods. The prepared samples were characterized by BET, Boehm titration test, XRD, SEM and EDS. The SEM exhibited that the morphologies of the samples prepared were significantly different from each other. Then the samples prepared were studied on the selective catalytic reduction (SCR) of NO with ammonia in the presence of oxygen. The SCR activity measurements were undertaken in a fixed-bed unit with a sieve plate in the middle. From the contrastive experiments, the results showed that linear V₂O₅/AC had the best denitration performance and the denitration rate was up to 57.41%. It was speculated that the linear V₂O₅ with the crystal faces (110) may show the best performance in SCR. And the durability results also showed that linear V₂O₅/AC produced a denitration rate of 47.7% after three regenerations.

P(BA-GMA) (PBG), having various molecular weights, was synthesized by in situ polymerization of butyl acrylate (BA) and glycidyl methacrylate (GMA), and further used as a modifier to improve the comprehensive properties of the epoxy curing system. The copolymers were characterized by gel permeation chromatography (GPC). The effects of various molecular weights of copolymers on the mechanical properties, thermal performance, and phase behavior of the curing system were carefully evaluated. The experimental results of differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) showed that glass transition temperature decreased and the tan δ peak shifted to a lower temperature with decreasing molecular weight of copolymer. Mechanical properties analysis of curing films showed that the impact strength and fracture toughness increased significantly upon the addition of PBG, indicating good toughness of the modified epoxy resins. From scanning electron microscopy (SEM) studies of the fracture surfaces of ER/PBG systems, the fracture behavior of epoxy matrix was changed from brittleness to toughness.

In-service structural health monitoring (SHM) technologies are critical for the utilization of composite aircraft structures. We developed a Lamb wave-based in-service SHM technology using built-in piezoelectric actuator/sensor networks to monitor delamination extension in a full-scale composite horizontal tail. The in-service SHM technology combine of damage rapid monitoring (DRM) stage and damage imaging diagnosis (DID) stage allows for real-time monitoring and long term tracking of the structural integrity of composite aircraft structures. DRM stage using spearman rank correlation coefficient was introduced to generate a damage index which can be used to monitor the trend of damage extension. The DID stage based on canonical correlation analysis aimed at intuitively highlighting structural damage regions in two-dimensional images. The DRM and DID stages were trialed by an in-service SHM experiment of CFRP T-joint. Finally, the detection capability of the in-service SHM technology was verified in the SHM experiment of a full-scale composite horizontal tail. Experimental results show that the rapid monitoring method effectively monitors the damage occurrence and extension tendency in real time; damage imaging diagnosis results are consistent with those from the failure model of the composite horizontal tail structure.

We investigated the effect of structural factor and amide grafted multi-walled carbon nanotubes (MWNTs-NH₂) on crushing characteristics of filament wound CFRP tube under quasi-static compression conditon. It was found that CFRP tubes sequentially showed the brittle fracturing mode, the local buckling fracturing mode and transverse shearing fracturing mode with increasing winding angle, respectively, with the characterizations by mechanical testing, SEM and optical microscopy. Moreover, crack propagation initiated by pre-crack and subsequent failure in the tube were strongly dependent on pre-crack angle due to deflection and penetration competition of crack evolution. The simulated compression failure behavior correlated well with the experimental results, revealing that the Chang-Chang failure criterion was effective in representing the quasistatic crushing characteristics of the tube. In addtion, the MWNTs-NH₂ were sucessfully obtained by multistep functionization. The compressvie properties of the tubes were significantly improved by the addition of the MWNTs-NH₂ due to their uniform dispersion and high interfacial chemical reactivity, whereas the as-received MWNTs and other functionalized MWNTs were not as effective.

SiCp/2024 aluminum alloy matrix composite was prepared by powder metallurgy method. Effects of heat treatment on the microstructure and mechanical properties of composite were investigated by SEM, EDS, XRD, HREM, tensile and hardness tests. The experimental results showed that SiC particles distributed uniformly in the matrix and were in good combination with matrix. The tensile strength and hardness were improved significantly after heat treatment. With the increase of solid solution temperature, the alloy phases dissolved in the matrix gradually. When the solid solution temperature arrived at 505 °C, the alloy phases dissolved thoroughly, and the composite exhibited the highest tensile strength and hardness (δ _b=360 MPa, HBS=104). The main strengthening phase was Al₂Cu, which was granular and distributed dispersively in the matrix. Effect of T6 was better than that of T4 at the same solid solution temperature.

Poly (urea-formaldehyde) (UF) microcapsules with epoxy resin E-51 as core material used as self-healing materials were prepared by interfacial polymerization method. The surface of UF microcapsules was modified by γ-(2,3-epoxypropoxy) propytrimethoxysilane (KH-560). The interfacial interactions between UF microcapsules and KH-560 were studied by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectrometric analysis (XPS) of microcapsules. The surface topography of microcapsules was characterized by scanning electron microscopy (SEM). The thermal stability and mechanical properties were evaluated. FTIR and XPS results showed that there were physical and chemical combinations between the silicon coupling agent and the microcapsules surface. The thermal stability and mechanical property analysis showed that the addition of KH-560 could greatly improve the thermal stability, tensile property and elastic property. SEM results indicated that the addition of KH-560 could improve the bonding between the surface of microcapsules and resin matrix and improve the ability of self-healing.

In order to improve the comprehensive utilization of solid waste such as iron tailings and waste glass and so on, mechanical property test of cement tailings mortar mixed waste glass and curing mechanism research were conducted in the key materials mechanics lab of Liaoning province. The experimental results show that adding waste glass particles can improve the grain size distribution of tailings. The effect is proportional to the content. The compressive strength of tailings mortar has increased significantly. The fineness modulus of tailings mortar mixture adding waste glass powder was gradually reducing with the increase of the dosage of waste glass powder, but the compressive strength of the mixture has gradually enhanced with the increase of the dosage. Microscopic analysis shows that the waste glass particles in the mortar mainly play a role of coarse aggregate and glass powder after grinding fine below a certain size shows strong volcanic activity, which can act hydration with tailings, at the same time glass powder also, plays a role in fine aggregate filling. Therefore, all of glass particles and glass powder can be used as the additive material for improving and optimizing the mechanical property of tailings mortar.

Cadmium sulphoselenide was synthesized continuous substitution solid solution and the only known pigment to yield bright red color on ceramic decoration. Encapsulated cadmium sulphoselenide pigments could yield abundant hues from yellow to red with high opacity at high temperature. The color generation has a linear function relation with the substitution rate. The encapsulation formation process of zirconium silicate encapsulated cadmium sulphoselenide was shown. Insufficient encapsulation efficiency and potential hazard to human and environment had limited the industrial application of cadmium sulphoselenide red pigment. Ink-jet printing decoration required fine size cadmium sulphoselenide red pigment on ceramic decoration. The review mainly focused on the synthesis techniques and industrial application of cadmium sulphoselenide red pigment.

The aim of this study was to improve the capacity for crack-repair in concrete by developing a new way. The self-healing agent based on biological carbonate precipitation was developed. Crack-healing capacity of the cement paste specimens with this biochemical agent was researched. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the precipitation in cracks. The healing efficiency was evaluated by measuring the water permeability after crack healing as well.The experimental results show that the applied biochemical agent can successfully improve the self-healing capacity of the cement paste specimens as larger cracks can be healed. The cracks with a width of 0.48 mm in the specimens with the biochemical agent are nearly fully healed by the precipitation after 80d repair. SEM and XRD analysis results demonstrate that the white precipitation in cracks is calcium carbonate, which displays spherical crystal morphology. Meanwhile, the water permeability test result shows that the biochemical agent can significantly decrease the water permeability of the cement paste specimens, the water permeability of specimens with the biochemical agent respectively decreases by 84% and 96% after 7 d and 28 d immersion in water, however the control specimens only respectively decrease by 41% and 60%, which indicates that the bacteria-based concrete appears to be a promising approach to increase concrete durability.

We prepared concretes (RC0, RC30, and RC100) with three different mixes. The poresize distribution parameters of RAC were examined by high-precision mercury intrusion method (MIM) and nuclear magnetic resonance (NMR) imaging. A capillary-bundle physical model with random-distribution pores (improved model, IM) was established according to the parameters, and dry-shrinkage strain values were calculated and verified. Results show that in all pore types, capillary pores, and gel pores have the greatest impacts on concrete shrinkage, especially for pores 2.5-50 and 50-100 nm in size. The median radii are 34.2, 31, and 34 nm for RC0, RC30, and RC100, respectively. Moreover, the internal micropore size distribution of RC0 differs from that of RC30 and RC100, and the pore descriptions of MIM and NMR are consistent both in theory and in practice. Compared with the traditional capillary-bundle model, the calculated results of IM have higher accuracy as demonstrated by experimental verification.

Effects of the strain rate on cement paste, mortar and concrete were studied. A modified SHPB testing technique with flattened Brazilian disc (FBD) specimen was developed to measure the dynamic tensile stress-strain curve of materials. A pulse-shaped split Hopkinson pressure bar (SHPB) was employed to determine the dynamic tensile mechanical responses and failure behavior of materials under valid dynamic testing conditions. Quasi-static experiments were conducted to study material strain rate sensitivity. Strain rate sensitivity of the materials was measured in terms of the stress-strain curve, elastic modulus, tensile strength and critical strain at peak stress. Empirical relations between dynamic increase factor (DIF) and the material properties were derived and presented.

Ion transport of sandwich cementitious materials (SCM) exposed to chloride environment was investigated by accelerated diffusion method and natural diffusion method. Pore structure and micromorphology of SCM were investigated by MIP and SEM-EDS. In comparison with the monolayer structural high performance concrete (HPC), conductive charge for 6 hours, chloride diffusion coefficient, and apparent chloride diffusion coefficient of SCM were decreased by 30%-40%, two orders of magnitude and 40%-50%, respectively. Pore structure of ultra low ion permeability cementitious materials (ULIPCM) prepared for the facesheet is superior to that of HPC prepared for the core. As for porosity, the most probable pore radius, the content of pores with radius ≥ 50 nm and the surface area of pores, the order is ULIPCM<HPC. The modifying degree of interfacial transition zone of the facesheet is much more than that of the core.

In order to further understand the wear mechanisms of cemented carbide cutter head of conical pick, six wornout cutter heads were investigated detailedly through scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). Abrasion wear and tipping were found to be the main wear mechanisms of the worn out cutter heads. Thermal stress and impact load played important roles in the wearing process of cutter heads. The intermixed mineral particles in the worn out areas aggravated the wear on the surface of cemented carbide. The spherical particles and vine-like structures were found to distribute in the wornout areas arbitrarily, and the compositions of which were detected using EDS.

The surface morphology, cross-sections, and joint break force (JBF) of joints welded under different electrode forces were studied. The defects, such as electrode sticking, notch, and excessive expulsions, were observed in the joints. No desirable joints were achieved with the consideration of weld geometries and joint performances. From the cross-sectional morphology, the joint evolution during the RMW of Pt alloy and 316 LVM SS wires was developed, which involved cold collapse and heat promoted set-down of Pt alloy wire, unbalanced heating at interface, molten phase squeezed out, and defect formation. Finally, the defect formation was also discussed.

The purpose of this study was to evaluate the antibacterial properties of experimental nano silver-containing cements (NSCs) using rat caries disease model. Nano silver base inorganic antibacterial powder was added to the reinforced glass ionomer cement at three different weight ratios to obtain a series of nano silver-containing cements, then two orthodontic cement products and three NSC samples were implanted into rat caries disease model, and their antibacterial properties were evaluated by the scanning electron microscope(SEM). Moreover, the rat caries disease model were established by inoculating cariogenic bacteria S mutans into antibiotics treated rat mouths and feeding with cariogenic diet. The tested materials were bonded on the surface of the buccal half crowns of the upper first premolar, and then fixed under the rats’front teeth lingual side to acquire enough retention. The SEM results indicated that the growth of streptococcus mutans was very active in group of Transbond XT. One month later, S mutans scattered on the GC Fuji ORTHO LC surface, and then the number significantly increased and arranged in chains after three months. In groups of NSC2, NSC3 and NSC4, the number of S mutans presented the downward trend and tended to disperse individually with the increase of silver nanoparticle content. We may conclude that the incorporation of silver nanoparticle enhanced GC Fuji ORTHO LC the adhesion restrain and killing effect to S mutans.

The aim of this study was to fabricate composite gel beads based on natural polysaccharides. Hyaluronic acid (HA) and Chitosan (CS) were successfully admixed with Ca²⁺/alginate (SA) gel system to produce SA/HA/CS gel beads by dual crosslinking: the ionic gelation and the polyelectrolyte complexation. The preparation procedure was that the weight ratio of SA (2%, m/v) to HA (2%, m/v) was kept at 2:1, then the mixture was dripped into the Ca²⁺ solution for ion-crosslinking, and finally polyelectrolyte crosslinked with 2% low molecular weight CS (LMW-CS) for 1.5 hours. The optimal formulation was achieved by adjusting the concentration and the weight ratio of SA, HA and LMW-CS. Due to the incorporation of HA and LMWCS, the swelling ratio of the beads at pH 7.4 was increased up to 120, and the time for the maximum swelling degree was prolonged to 7.5 h. The swelling behavior was obviously improved compared to the pure SA/Ca²⁺ system. The preliminary results clearly suggest that the SA/HA/CS gel beads may be a potential candidate for biomedical delivery vehicles.

The specific binding of receptor to ligand covalently attached to surface with different surface densities was studied using streptavidin-biotin model pair. Biotinylated substrates with different spacer thicknesses as formed through a simple reaction between amine immobilized surfaces and N-hydroxysucciimide groups at the end of biotin modified PEG in anhydrous organic solutions (“grafting to” technique). The amount of the specifically adsorbed protein was measured as a function of spacer thickness between hard surface and biotin moieties. It has been shown that the amount of specifically adsorbed streptavidin decreases with the increase spacer thickness and the protein adsorbs onto the functionalized surfaces in a single molecular manner. It provides an interesting model system for studying single molecular interactions.

Nanocomposites (PMSEPE/Q₈M₈ ^H) were prepared via solution blending of octakis(dimethylsiloxy)octasilsesquoixane (Q₈M₈ ^H) into poly(dimethylsilyleneethynylenephenyleneethynyle ne) (PMSEPE). PMSEPE/Q₈M₈ ^H nanocomposites were characterized by Fourier transform infrared (FT-IR) spectroscopy, rheological measurement, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). The experimental results show that the hydrosilylation reaction in PMSEPE/Q₈M₈ ^H nanocomposites occurs slowly exceeding 180 °C. PMSEPE/Q₈M₈ ^H nanocomposites can be cured at temperatures less than 260 °C and the cube structure of Q₈M₈ ^H keeps stable during the curing process. POSS domains are evenly dispersed in the cured nanocomposite. However, serious aggregation of POSS occurs at 15% Q₈M₈ ^H content. The thermal and thermooxidative stabilities of PMSEPE/Q₈M₈ ^H nanocomposites obviously depend on the content of Q₈M₈ ^H. The incorporation of Q₈M₈ ^H can effectively enhance the thermal and thermooxidative stabilities of cured PMSEPE. PMSEPE/Q₈M₈ ^H nanocomposites can be the candidates for applications in high temperature environment.

A new fiber optic sensor based on the oxidation of 2,4-dichlorophenol (DCP) catalyzed by iron(II) phthalocyanine (Fe(II)Pc) was developed for the determination of DCP. The optical oxygen sensing film containing fluorescence indicator Ru(bpy)₃Cl₂ was used to detect the consumption of oxygen in solution. Moreover, a lock-in amplifier was used to determine the lifetime of the sensor head by detecting its phase delay change. The results reveal that the sensor has a linear detection range of 1.0×10^-6 - 9.0×10^-5 mol/L and a response time of 5 min. The sensor also has high selectivity, good repeatability and stability. It can be used effectively to determine DCP concentration in real samples.

We applied LDHs to modify the bitumen by melt blending, and studied the viscoelasticity of LDHs modified bitumen by means of dynamic shear rheometer (DSR). The creep test was used to evaluate the viscoelastic behavior. The experimental results indicated that, due to the addition of the LDHs, the viscoelastic properties of modified bitumen were superior to those of pristine bitumen. Therefore, the LDHs would be an alternative to modifiers used in the bitumen to improve the UV-aging resistance during the service of asphalt pavement.

Carbon aerogels were synthesized via ambient pressure drying process using resorcinolformaldehyde as precursor and P123 to strengthen their skeletons. CO₂ activation technology was implemented to improve surface areas and adjust pore size distribution. The synthesis process was optimized, and the morphology, structure, adsorption properties and electrochemical behavior of different samples were characterized. The CO₂-activated samples achieved a high specific capacitance of 129.2 F/g in 6 M KOH electrolytes at the current density of 1 mA/cm² within the voltage range of 0-0.8 V. The optimized activation temperature and duration were determined to be 950 °C and 4 h, respectively.

The microstructure evolution and formability of Ti-10V-2Fe-3Al alloy related to the initial microstructures and processing variables were investigated during hot forming process. The experimental results show that the α-phase growth is controlled by solute diffusion during the heat treatment processes. Four different microstructures were established by combinations of several heat treatments, and Ti-10V-2Fe-3Al alloy shows excellent formability both above and below the β transus temperature. The alloy possesses low deformation resistance and active restoration mechanism during the deformation. A constitutive equation describing the hot deformation behavior of Ti-10V-2Fe-3Al alloy was obtained. Higher flow stress was observed for the acicular morphology of α phase in microstructures with large aspect ratios as compared with that of small aspect ratios. Due to the dynamic recovery in soft β phase, and the dynamic recrystallization and breakage of acicular α-phase, flow softening occurred significantly during deformation. Dynamic recrystallization also occurred especially in the severely deformed regions of forged parts.

The structural stability, thermodynamic and optical properties of delafossite CuAlO₂ were investigated using the norm-conserving pseudopotential technique based on the first-principle density-functional theory. The ground-state properties obtained by minimizing the total energy were in favorable agreement with previous works. By using the quasi-harmonic Debye model, the thermodynamic properties including the Debye temperature Θ_D, heat capacity C _V, thermal expansion coefficient α, and Grüneisen parameter γ were successfully obtained in the temperature range from 0 to 1 000 K and pressure range from 0 to 80 GPa, respectively. The optical properties including dielectric function ε(ω), absorption coefficient α(ω), reflectivity coefficient R(ω), and refractive index n(v) were also calculated and analyzed.