A series of nanocrystalline V-doped (0.0–3.0 at.%) TiO₂ catalysts have been successfully prepared by the one-step solution combustion method using urea as a fuel. The obtained powders were characterized by XRD, SEM, Raman, XPS and UV-Vis DRS. The effects of V doping concentration on the phase structure and photocatalytic properties were investigated. XRD, Raman, and XPS show that V doping diffuses into TiO₂ crystal lattice mainly in the form of V⁵⁺ and causes a phase transition from anatase to rutile. V doping can widen the light absorption range of TiO₂, with the absorption threshold wavelength shifting from 425 to 625 nm. The photocatalytic activity of V-doped TiO₂ powders were evaluated by the photocatalytic degradation of methyl orange (MO) under visible light irradiation. It is found that V doping enhances the photocatalytic activity under visible light irradiation and the optimal degradation rate of MO is about 95.8% with 1.0 at% V-doped TiO₂.

Pure alumina ceramic tube and 95 alumina ceramic (the ceramic with 95.84% alumina) tube were prepared by using self-prepared alumina micrometer powder without agglomeration as raw material. The ceramic green was shaped by isostatic pressing and sintered at different temperature from 800 to 1 600 °C for 2 h. The 95 ceramic tube sintered at 1 550 °C for 2 h had mean particle size of 4 μm, bend strength of 437 MPa and volume density of 3.714 g/cm³. Shape memory effect during sintering was observed. XRD results showed that no phase transition occurred during shape memory process, which indicated that shape memory effect was not caused by phase transition. Several probable causes of the alumina ceramic shape memory effect were discussed in this paper.

Li-doped ZnO thin films had been grown by radio frequency magnetron sputtering and then annealed under various annealing temperatures. The characteristics of ZnO films were examined by XRD, FESEM, Hall measurement and optical transmission spectra. Results showed that p type conduction was observed in Li doped ZnO films annealed at 500–600 °C and the p type ZnO films possessed a good crystalline with c-axis orientation, dense surface, and average transmission of about 85% in visible spectral region.

Diatomite was used as raw material to prepare sodium silicate with a modulus of 3.1 by alkali dissolution method and the resulted sodium silicate solution was employed as a precursor. Methyl methacrylate monomers were introduced in wet gels through solution-immersion, and upon heating at 70 °C, the mesoporous surfaces throughout the skeletal framework were coated with the polymer layer. PMMA modified silica aerogels were successfully synthesized via ambient pressure drying. The properties were investigated by FTIR, NMR, TGA, nitrogen adsorption-desorption, FESEM and nano-indentation, etc. Results indicate that with the increasing of PMMA incorporated into silica aerogels, the bulk density and the BET surface area increase, the porosity decreases. Through the observation of FESEM, it is found that the interconnecting pores and the big pores add, the pore size distribution expands from 5–17 to 28–150 nm. By comparison, the PMMA modified silica aerogels achieve a 52-fold increase in hardness and a 10-fold increase in modulus.

In order to investigate the anti-leaching capability of pyrochlore Gd₂Zr₂O₇ immobilized An³⁺, trivalent neodymium was used as the simulacrums for radioactive wastes with trivalence, Gd_2−xNd _xZr₂O₇(0.0⩽x⩽2.0) series samples were successfully synthesized by high temperature solid reaction and using Gd₂O₃, ZrO₂ powders as starting materials. The experiments of long-term chemical stability were conducted in synthetic seawater at 40 and 70 °C. The XRD diffractive data and extraction ratio of as-received samples were collected with the help of X-ray diffraction (XRD) instrument and inductively coupled plasma mass spectrometry (ICP-Mass). The results indicate that the phases of as-received compounds keep the single phase of pyrochlore. The extraction ratio of Gd³⁺, Zr⁴⁺ and Nd³⁺ in waste forms is increasing with the increase of immersion time in synthetic seawater. The extraction ratio of waste forms at 70 °C is higher than at 40 °C. The highest extraction ratio of Gd³⁺, Zr⁴⁺ and Nd³⁺ after 42 days is near 0.025 8, 0.003 8 and 0.045 2 μg·mL⁻¹, respectively.

The Si₃N₄-BN composites have been prepared via die pressing and precursor infiltration and pyrolysis route using borazine as precursor, and the effect of sintering additives on properties of the composites has been investigated. After sintering additives are adopted, the α to β phase transition of Si₃N₄ and the mechanical properties of the composites at both room temperature and high temperature are all increased with small extent. When using Y₂O₃+Al₂O₃ as additives, the phase transition of Si₃N₄ and the mechanical properties of the composites have better results. The β-Si₃N₄ content is 17.47%. The flexural strength, elastic modulus and fracture toughness of the composites are 188.74 MPa, 84.34 GPa and 2.96 MPa·m^1/2, respectively. After exposed at 1 000 °C in the air for 15 min, the flexural strength of the composites is 154.62 MPa with a residual ratio of 81.92%. The elongated β-Si₃N₄ grains appear in all composites with different sintering additives. Relatively more rod like β-Si₃N₄ grains can be observed in composites with Y₂O³⁺Al₂O₃ as additives, making it to possess better mechanical properties.

Solid superacid SO₄ ²⁻/ZrO₂-SiO₂ was prepared by dip-impregnation method, and its catalytic activity was tested with esterification of p-nitrobenzoic acid and methanol. The optimum conditions were also found, that is, the molar ratio between silica and zirconia was 10:1, the calcination temperature was 550 °C and the soaked consistency of H₂SO₄ was 1.0 mol·L⁻¹. Under the conditions that the ratio of methanol to acid(mL/g) was 12:1, the amount of catalyst was 0.5 g, the reaction time was 5 h and the stirring speed was 800 r·min⁻¹, the yield of methyl p-nitrobenzoate could reach up to 90.5%. Then the characterizations of cataslyst, including the acidity and types of acidic centers, specific surface area and surface structure was respectively examined by Hammett indicator, in-situ pyridine IR, BET method, FT-IR(KBr), transmission electron microscope (TEM), and X-ray diffraction (XRD). The results showed that the catalyst SO₄ ²⁻/ZrO₂-SiO₂ was superacid with high specific surface area due to H _o<-12.70. It contained acidic sites of Lewis and Brψnsted, and its surface structure changed after esterification. The zirconia crystal was mainly tetragonal and silica crystal was not found.

In this work, n-type amorphous silicon oxide thin films were deposited by RF-PECVD method using a gas mixture of SiH₄, CO₂, H₂, and PH₃. The deposition rate, refractive index, band gap, crystalline volume fraction, and conductivity of the silicon oxide thin films were determined and analyzed. The film with refractive index of 1.99, band gap of 2.6eV and conductivity of 10⁻⁷ S/cm was obtained, which was suitable for the intermediate reflector layer.

In order to improve the tribological properties of ceramic composites, Al₂O₃/TiC-Al₂O₃/TiC/CaF₂ self-lubricating laminated ceramic composites were prepared by vacuum hot pressing sintering. Experiments were conducted to get mechanical properties and the friction and wear properties were also measured with friction and wear tester. The worn surfaces were observed by scanning electron microscope (SEM) and energy dispersion spectrum (EDS). The wear resistance properties and the self-lubricating effect of ceramic composites were analyzed. Results show that the Al₂O₃/TiC-Al₂O₃/TiC/CaF₂ self-lubricating laminated ceramic composites layers are well-defined with a higher bonding strength and the mechanical performances are uniform enough to overcome the anisotropy of weak laminated ceramic composites. In addition, the fracture toughness of Al₂O₃/TiC layers is also improved. Its friction coefficient and wear rates decrease with the increase of rotation speed and load. Al₂O₃/TiC-Al₂O₃/TiC/CaF₂ self-lubricating laminated ceramic composites have good wear resistance because of the tribofilm formed by the CaF₂ solid lubricants. The wear mechanisms of Al₂O₃/TiC/CaF₂ layers are abrasive wear and Al₂O₃/TiC layers are adhesive wear.

Ca_1−xRb _xCu₃Ti₄O₁₂ (x=0, 0.01, 0.02 and 0.03) ceramics were synthesized by the sol-gel method. Doping Rb⁺ reduces dielectric loss, which reaches minimum when x=0.02. By measuring properties of electrical conduction, larger leakage current density and height of grain-boundary Schottky potential barrier (ϕ_B) were found in the doped samples, and ϕ_B became maximum when x=0.02. These results are attributed to the increase in the amount of oxygen vacancies and the formation of Cu-rich/Ti-poor grain-boundary layers, and it can be concluded that the dielectric loss in CCTO ceramic can be reduced by manipulating the composition and electrical properties of grain boundary.

Prepreg properties including cure kinetics, cure shrinkage, and coefficient of thermal expansion were analyzed. A simulation method based on “element birth and death” method of Finite element analysis (FEA) was presented to simulate the cutting process and predict the machining deformation for composite laminates and stiffened panels. The comparisons between the simulation results and experimental data showed good agreement. It is found that residual stresses are the main source of machining deformation for composites and machining deformation is expected to happen only if there are stress gradients along the machining direction. There is no machining deformation for composite laminates due to its uniform stresses distribution in plane, while machining deformation can be observed obviously for T-shape stiffened composite panels. Attention should be paid to machining deformation to avoid the mismatch during assembly.

A new method to predict the ultimate strength of fiber reinforced composites under arbitrary load condition is introduced. The micromechanics strength theory is used to perform the final failure prediction of composite laminates. The theory is based on unit cell analytic model which can provide the ply composite material properties by only using the constituent fiber and matrix properties and the laminate geometric parameters without knowing any experimental information of the laminates. To show that this method is suitable for predicting the strength of composite laminates, the micromechanics strength theory is ranked by comparing it with all the micro-level and the best two macro-level theories chosen from the World Wide Failure Exercise. The results show that this method can be used for predicting strength of any composite laminates and provide a direct reference for composite optimum design.

A novel powder catalyst Cu-Cr-O applied to the synthesis of carbon nanotubes (CNTs) was developed, which was prepared via ammonia precipitation method. Techniques of thermo-gravimetric/differential scanning calorimeter (TG-DSC), X-ray diffraction (XRD) as well as scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have been employed to characterize the thermal decomposition procedure, crystal phase and micro structural morphologies of the as-synthesized materials, respectively. The results show that carbon nanotubes are successfully synthesized using Cu-Cr-O as catalyst when the precursors are calcined at 400, 500, 600, and 700 °C. The results indicate that the calcination of the Cu-Cr-O catalyst at 600 °C is an effective method to get MWCNT with few nano-tube defects or amorphous carbons.

This paper presents the way to harvest mechanical energy from asphalt pavement by piezoelectric generator. Results show that the potential energy in asphalt pavement can be up to 150 kW/h per lane per kilometre. Part of the mechanical energy can be harvested by piezoelectric transducers. The performance of seven typical transducers is examined through finite element analysis. Results show that PZT piles and multilayer, cymbal and bridge can work in asphalt pavement environment. PZT piles and multilayer have higher energy converting rate. However, the total harvested energy is small if these transducers are embedded directly in pavement. A prototype pavement generator is developed using PZT piles to increase the harvested energy. The generator can harvest more than 50 kW/h energy from the pavement under heavy traffic. 8–16 PZT piles are recommended for one generator. Round shape is suggested for the PZT piles to reduce the concentration of stress. And multilayer structure is recommended for PZT piles to decrease the electric potential of generator. The generator can be extended as sensor in the asphalt pavement, which can be used to monitor the traffic, pavement stress and temperature.

Cracks can deteriorate mechanical properties and/or durability of concrete. A few studies have shown that, cracks can autogenously heal under a certain conditions besides the traditional passive repair with a deliberate external intervention. For underground concrete structures, the presence of water, as a necessity for chemical reactions of the healing additives, is beneficial to healing concrete. In this paper, a natural healing method by mineral additives was developed according to the chemical and physical characteristics of underground environment. The healing capacity of three different crystalline mineral materials classified namely, carbonate, calcium sulphoaluminate expansive agent and natural metakaolin due to permeation-crystallization, expansion and pozzolanic reaction, has been assessed from the mechanical properties, referring to the relative elastic modulus, the strength restoration, and the water permeability of the healed specimens. In addition, the morphology of the healing products in the vicinity of the crack was observed. The results indicate that the specimens incorporated with the three mineral additives show different healing capacity according to the improved mechanical properties and permeability. The permeability of the host matrix decreased a lot after crack healing by natural metakaolin followed by carbonate whereas no noticeable improvement of water permeability has been observed for the specimens mixed with expansive agent. The specimens incorporated with carbonate show the best mechanical restoration in terms of relative elastic modulus and compressive strength. Although the dominate element is CaCO₃ by reaction of CO₃ ²⁻, either from the dissolved CO₂ or from the additives, and Ca²⁺ in the cementitious system to fill the cracks, the healing capacity depends greatly on the morphology and the properties of the newly formed products.

Circulating fluidized bed combustion (CFBC) ash exhibits the desirable pozzolanic activity which makes it a potential supplementary cementitious material to replace cement for concrete production. However, the high unburnt carbon content and porous surface structure of CFBC ash may adsorb water reducer and thereby significantly reduce the efficiency of water-reducing agents. The adsorption mechanism of polycarboxylate superplasticizer in CFBC ash-Portland cement paste was investigated by ultraviolet-visible spectrophotometer, and the conception of “invalid adsorption site” of CFBC ash was presented. The results show that the adsorption behavior of polycarboxylate superplasticizer in coal ash-Portland cement paste can be described by Langmuir isothermal adsorption equation. The adsorption capacity of CFBC ash-Portland cement paste is higher than that of pulverized coal combustion (PCC) fly ash-Portland cement paste. Moreover, the adsorption amount of polycarboxylate superplasticizer increases with the ratio of ash-to-cement in the paste. At last, the fluidity of CFBC ash-Portland cement paste is lower than that of the PCC fly ash paste. This work suggests that when CFBC ash is used as concrete admixture, the poor flowability of the cementitious system due to the high adsorption of water and water-reducing agent should be taken into consideration.

The characters of basalt fiber are analyzed and compared with commonly used fibers. The rheological behaviors of the basalt fiber reinforced asphalt mastic are investigated by the dynamic shear rheological tests and the repeated creep tests. The results show that basalt fiber has excellent reinforced performances, such as high asphalt absorption ratio, low water absorption ratio, high tensile strength, high elastic modulus and high temperature stability. The rutting factor of the fiber reinforced asphalt mastic is higher than the plain asphalt mastic and the reinforced effects are more remarkable under high temperature. The rheological performances of the asphalt mastic demonstrate a good linear relationship between different temperature and loading frequency. The creep stiffness modulus of the asphalt mastic at different loading time can be expressed by power function. Improved Burgers model is used to represent the rheological behaviors of the asphalt mastic with basalt fiber and the model parameters are estimated.

The quality of compaction is important to the performance of hot mixed asphalt (HMA) pavement. Most premature failures of asphalt pavement are concerned with poor compaction. Compaction characteristic of HMA mixtures were studied. Compaction tests were done with typical widely used HMA mixtures, including dense gradation asphalt mixtures with different nominal maximum aggregate size (AC13,AC20,AC25), and mixtures with different gradation (AC13, SMA13,Sup13 and OGFC13). HMA mixtures were sampled at different compaction temperature and Marshall blow numbers, varying between 60 and 175 °C and between 15 and 75 lows, respectively. The compaction characteristics of these mixtures were evaluated. The results showed that the Marshall stability and volumetric properties were significantly affected by the compaction temperature. Mixtures with the same NMAS but different type of gradation need different compaction energy to get the designed density.

In order to quantitatively describe the local corrosion process of steel bars in cracked concrete area, a new two-staged utility model is established, and the effect of transverse cracks on the reinforcement corrosion is analyzed from the angle of long-term service performance evaluation for reinforced concrete structure. Moreover, based on the principle of spectral analysis for environmental action of concrete, an equivalent relationship is established between the corrosion rate in the natural environment and that under the standard temperature and relative humidity condition according to the principle of equivalent annual corrosion depth. Comparison between the inspection results from some references and the calculated values by the two-staged utility model validates the feasibility of the proposed model. The model was applied to Chinese Railway Track System (CRTS)II ballastless track slab with transverse dummy joints, from which satisfactory results of corrosion degree of steel bars were obtained.

The traditional alumina-silicate raw materials, for example, clays, in the precalcining technique of cement production, have been replaced by low grade and high silica content sandstones, shales, and industrial waste residues, including fly ashes, slag, and others. The results are the change of compositions and characteristics of raw materials applied and a great effect on cement calcination process and clinker formation. In this work, the cement clinker formation process of different alumina-silicate raw materials to replace clay raw material was studied by chemical analysis, X-ray diffraction, differential thermal analysis, and high temperature microscope based on the characteristics of the alumina-silicate raw materials. The formation heat of the clinker was determined by the acid dissolution method. Influence of different alumina-silicate raw materials on the clinker burnability and formation process was studied. The results show that the changing of alumina-silicate raw materials, especially using industrial waste residues, can reduce the formation temperature of high temperature liquid phases, improve the burnability of raw materials, reduce the formation temperature and formation heat of clinker. And this study also observed the formation temperature and transformation of high temperature liquid phases in the heating process of raw materials by high temperature microscope.

The reaction models and the quantitative calculation on the volume fraction of hydration products for binary ground granulated blast-furnace slag (GGBFS) cement system are presented, in which two important factors are taken into account, i e, the reactivity of GGBFS influenced by its chemical compositions and the partial replacement of aluminum phase in calcium silicate hydrate (C-S-H) gel. A simplified treatment is further suggested towards the quantification. In particular, when the replacement level of GGBFS is lower than 70%, the ratio of calcium over silica (C/S) is set at 1.5 or at 1.2 otherwise. The validity of the proposed model is addressed in terms of the contents of calcium Portlandite and non-evaporable water.

Crushable ceramic foams are more suitable to be used as an arrestor material applied in engineered materials arresting system (EMAS) for airport runway for their properties of widely controllable strength, negligible crushing-rebounding behavior, durability, and chemically-inert composition, comparing with traditional concrete foams. The synthesis of ceramic foams adopted direct-foaming method and used an animal protein as foaming agent. Kaolin, talc powder and alumina were the main raw materials. Effects of the ratios of raw materials, calcination temperatures, heating rates, holding time, viscosities of polyvinyl alcohol (PVA) solution as well as the amounts of protein foaming agent and water on microscopic structure, densities, compressive strength and open porosities of ceramic foams were investigated systematically. The results indicate that ceramic foams with typical pore sizes 100–300 μm, open porosities from 73.1% to 91.5%, densities from 0.25 to 0.62 g·cm⁻³, compressive strength from 0.19 to 4.89 MPa, are obtained by properly adjusting the parameters mentioned above. And the mechanical strength meets the requirement for the EMAS for airport runway. In addition, good correlations are observed among compressive strength, open porosity, microscopic structure, and crystal phase. Furthermore, the possibility of producing the general dimensions of such aircraft arresting components with the proposed method was also discussed.

The primary objective of this paper was to study the mechanical properties and durability of the cement stabilized gravel by different compact method. The influence of rubber particle content on mechanical properties of samples was studied by compaction tests and freezing thawing recycle tests. Pore structure and fractal characteristic of mixture were analyzed quantitatively using mercury intrusion porosimetry (MIP). X-ray diffraction (XRD) was adopted to identify the composition phases. The morphology analysis in micro scale and elemental analysis of samples were carried out by scanning electron microscope (SEM). The optimum compressive strengths of rubber cement stabilized gravel (RCSG) with static compaction method and with vibratory compaction method were obtained by controlling compaction degree and vibration time, respectively. From the compaction tests, the vibratory compaction method is preferred compared with the static compaction method as better compressive strength can be improved by about 340%–360%. Besides, test results also reveal that compressive strength of samples with vibratory compaction method or static compaction method will decrease with the rubber particle bulk content increasing. The freezing thawing recycle tests indicate that freezing thawing resistance has been improved (frozen stability coefficient K has been increased from 0.89 to 0.97) by the addition of rubber particles. MIP tests show that the mean pore diameter and porosity of mixture have been increased from 70 to 250 nm and 9% to 24% respectively, with the rubber particles content increasing. Component analysis shows that the calcium silicate hydrate (CSH) is the predominant hydrate product with or without the addition of rubber particles.

The fatigue property of asphalt mixtures under complicated environment (low-temperature bending performance, chloride penetration, freezing-thawing cycle and their coupling effect) and the improvement effect for relevant property of basalt fiber-reinforcing asphalt mixture under complicated environment are studied. Two grading types of asphalt mixtures, AC-16I and AC-13I, are chosen, whose optimum asphalt-aggregate ratio and optimum dosage of basalt fiber are determined by the Marshall test. The standard specimens are made firstly, and then the low temperature bending tests of asphalt mixture and basalt fiber-reinforced asphalt mixture under the coupling effect of the chloride erosion and freezing-thawing cycle have been carried out. Finally, the fatigue property tests of asphalt mixture and basalt fiber-reinforced asphalt mixture under complex environment are performed on MTS material testing system. The results indicate that the tensile strength, the maximum curving tensile stress, the curving stiffness modulus, and fatigue properties of asphalt mixture are influenced by the coupling effect of the chloride erosion and freezing-thawing cycle. The low-temperature bending performance and fatigue property of asphalt mixtures under complicated environment can be greatly improved by adding moderate basalt fiber. The dense gradation asphalt mixture possesses stronger ability to resist adverse environmental effects under the same condition.

Synthesis of autoclaved aerated concrete (AAC) has been carried out with carbide slag addition, and the carbide slag could be used as a main material to produce the AAC with the compressive strength about 2 MPa and the density below 0.6 g·cm⁻³. In this study, quartz sand acted as frame structure phase in the matrix, and quartz addition also influenced the Si/Ca of starting material. Tobermorite and CSH gel were formed readily at 62%, which seemed to enhance the compressive strength of samples. Curing time seemed to affect the morphology of phase produced, and specimen with the plate-like tobermorite formed at 10 h appeared to have a better compressive strength development than the fiber-like one at 18 h. The higher curing temperature seemed to favor the tobermorite and CSH gel formation, which also exerted a significant effect on the strength development of the samples. On the micro-scale, the formed CSH gel was filled in the interface of the matrix, and the tobermorite appeared to grow in internal-surface of the pores and interstices. The tobermorite or/and CSH formation seemed to densify the matrix, and therefore enhanced the strength of the samples.

Ti-based composite coatings reinforced by in situ synthesized TiB and TiC were deposited on Ti₆Al₄V substrates by laser cladding. The effects of Y₂O₃ on the microstructure and cracking susceptibility of the coatings were investigated in details. It is shown that a small amount of Y₂O₃ addition can significantly refine the microstructure of the coatings by hastening spheroidization of the primary phase structure. The maximum refinement in microstructure was obtained with the optimum (2 wt%) addition of Y₂O₃. Moreover, it can increase the volume fraction of TiC and reduce the residual stress of the coatings due to the decrease in lattice distortion of the α(Ti) matrix. All of these factors lead to the reduction in cracking susceptibility of the coatings containing Y₂O₃ on the premise that the hardness of the coatings is improved. The fracture toughness of the coatings without and with Y₂O₃ (2 wt%) is 8.32 and 17.36 MPa·m^1/2, respectively. Scanning electron microscope examination reveals a transition of the fractured surfaces from cleavage fracture to quasi-cleavage fracture resulting from the Y₂O₃ addition.

Fly ash/A1-Mg composites are fabricated by powder metallurgical method. The morphology and structure of fly ash/A1-Mg composites are characterized by scanning electron microscope (SEM) and X-ray diffraction, respectively. The influences of different fly ash content on the friction and wear behavior of the composites are investigated at a constant sliding velocity of 400 r/min and the worn mechanism of composites is discussed. The results indicate that the friction coefficient is steadily lower than that of Al alloy matrix at the lower fly ash content and loads. For the fly ash/A1-Mg composites, the wear mechanism is characterized as abrasive wear and adhesive wear under small normal load and at low fly ash content, and it is characterized as delamination wear and abrasive wear transferred onto the counterpart under high normal load and at high fly ash content.

Incremental forming is a novel die-less sheet forming process. There is a need for special means to retain lubricant at the tool/sheet interface during forming. To fulfill the stated aim, a porous ceramic film was developed on pure Ti substrate, and it was done through an electrochemical depsition process known as plasma electrolytic oxidation. The film with preferred pore size could be realized after several attempts by varying the processing parameters. In order to characterize the film, a variety of tests including microstructure, film-substrate bond strength and tribological properties tests were conducted. On-job performance of the film was also examined by forming Ti components employing a range of forming conditions. It was found that the proposed method of lubrication was effective, and the plasma eletrolytic oxidation process can be employed to fabricate films on pure Ti sheet to provide means of lubrication during incremental forming.

The fabrication of high volume fraction (HVF) M₇C₃ (M=Cr, Fe) reinforced Fe-based composite coating on ASTM A36 steel plate using plasma transferred arc (PTA) welding was studied. The results showed that the volume fraction of carbide M₇C₃ was more than sixty percent, and the relative wear resistance of the coating tested on a block-on-ring dry sliding tester at constant load (100 N) and variable loads (from 100 to 300 N) respectively was about 9 and 14 times higher than that of non-reinforced α-Fe coating. In addition, under constant load condition the friction coefficients (FCs) of two coatings increased first and then decreased with increasing sliding distance. However, under variable loads condition the FCs of non-reinforced α-Fe based coating increased gradually, while that of HVF M7C3 reinforced coating decreased as the load exceeded 220 N. The worn surface of non-reinforced α-Fe based coating was easily deformed and grooved, while that of the HVF M₇C₃ reinforced coating was difficult to be deformed and grooved.

Dense Nb/Nb₅Si₃ composites were fabricated via spark plasma sintering technology using Nb, Si, and Al elemental powders as raw materials. The microstructures of the synthesised composites were analyzed through scanning electron microscopy, X-ray diffraction, and electron probe microanalysis. The results show that the composites consisted of residual Nb particle phase and Nb₅Si₃ phase. The microstructure of the Nb/Nb₅Si₃ in situ composites was evidently affected by Al addition, which prompted the formation of the Al₃Nb₁₀Si₃ phase. In addition, the Rockwell hardness of the composites decreased with the increase in Al additions. The Rockwell hardness of Nb-20Si is 60HRC, which decreased to approximately 52.7 HRC when the Al content increased to 15 at%. The oxidation resistance of the Nb/Nb₅Si₃ in situ composites significantly improved with the increase in Al addition.

C_f/Cu composite was prepared by vacuum melting infiltration. Ti and Cr were doped to the Cu alloy to improve the wettability between Cu and carbon. The microstructure was investigated by XRD, SEM and EDS. The arc erosion rate of Cf/Cu composite was investigated in vacuum. The results showed that the Ti and Cr could improve the wettability between Cu and C/C preform and the infiltration ability of Cu into C/C preform greatly. A TiC interface formed between the fibers and matrix. The good bonding between the fiber and matrix guaranteed that part of the Cu matrix can still be bonded on the fibers even when the material was exposed to the plasma. Consequently, the carbon fibers were protected from the erosion. In comparison, Cu was completely consumed by the arc erosion. Hence, the graphite was eroded and presented a cauliflower-like morphology. Therefore, the prepared C_f/Cu had better ability to resist the arc erosion, compared with common Cu-C material.

ZrO₂-Y₂O₃ ceramic coating was produced by plasma electrolytic oxidation (PEO) on ZAlSil₂Cu₃Ni₂ alloy. The microstructure and phase composition of the coating were investigated by SEM and XRD. The results show that adding an appropriate amount of yttrium ion can improve the growing rate of ceramic coating at different oxidation stages and decrease arc voltage. The thickness of ZrO₂-Y₂O₃ coating is 16 μm thicker than that of ZrO₂ coating and the maximum oxidation rate improves by 0.6 μm/min. In addition, the arc voltage decreases from 227 to 172 V. It can be seen that the rate of oxidation firstly increases to some extent and then decreases with the content of yttrium ion increasing. The growth rate reaches the maximum while the content of yttrium ion is 0.05 g·L⁻¹. The maximum thickness is 90 μm.Compared to ZrO₂ coating, the micropores of ZrO₂-Y₂O₃ coating are less and the ceramic layer is repeatedly deposited by ZrO₂ and Y₂O₃ ceramic particles. Meanwhile, the binding force between coating and substrate is better and the coating is uniform and compact. The ceramic layer is mainly composed of c-Y0.15Zr0.85O1.93□0.07, m-ZrO₂, α-Al₂O₃, γ-Al₂O₃ and Y₂O₃. It is indicated that ZrO₂ has been fully stabilized by yttrium ion through the formation of solid solution.

First-principles calculations have been carried out to investigate the structural stabilities, electronic structures and elastic properties of Mg₁₇Al₁₂, Al₂Ca and Al₄Sr phases. The optimized structural parameters are in good agreement with the experimental and other theoretical values. The calculated formation enthalpies and cohesive energies show that Al₂Ca has the strongest alloying ability, and Al₄Sr has the highest structural stability. The densities of states (DOS), Mulliken electronic populations, and electronic charge density difference are obtained to reveal the underlying mechanism of structural stability. The bulk modulus, shear modulus, Young’s modulus, and Poisson’s ratio are estimated from the calculated elastic constants. The mechanical properties of these phases are further analyzed and discussed. The Gibbs free energy and Debye temperature are also calculated and discussed.

Striped bone morphogenetic protein-2 (BMP-2) patterns are created on polystyrene (PS) surfaces by microcontact printing (μCP) to investigate the influences of the protein patterns on bovine chondrocytes behaviors. Due to the excellent ability of BMP-2 to recruit cells and the limited ability of blank PS areas to bind cells, bovine chondrocytes preferentially attach on the protein areas, leading to formation of cell patterns and elongated cell morphologies to some degree. The BMP-2 protein stripe can guide bovine chondrocytes adhesion and alignment. The pattern dimensions can significantly affect the cell adhesion and spread. The protein stripe width mainly controls the cell elongation and orientation while the pattern spacing mainly affects the cell spread towards neighboring stripes. Therefore, the cell morphology and distribution direction can be controlled by precisely designing the pattern shapes and sizes. We believe that the present study could find applications for surface modification of biomaterials’ surfaces to create the bioactive patterns to control chondrocytes adhesion, spreading and even cell function. It may be helpful for the development of novel biomaterials for cartilage repair.

In order to accelerate the chronic wounds healing, we investigated the healing effects of bioactive glass and Yunnan baiyao ointments in streptozotocin-induced diabetic rats. The ointments were prepared by mixing 45S5 bioactive glass powder (16% weight) with Vaseline and different weight percentages of Yunnan baiyao. Full-thickness defect wounds were created on the back of 130 SD rats and were randomly divided into 8 groups. The wound healing rates were calculated at 4, 7, 10, 14 and 21 days after surgery. The samples were harvested for further observations. Considering the wound closure rate, group 6 (with 5% Yunnan baiyao) has better wound healing performance than other diabetic groups. The lower inflammatory response was observed by gross observation and confirmed by the results of H&E staining and TEM observation. Besides, the proliferation of fibroblasts, the formation of granulation tissue, as well as the vascularization, were improved in group 6 compared to other diabetic groups. All results suggest that bioactive glass and Yunnan baiyao ointments can accelerate the recovery of diabetes-impaired skin wounds, and comparing to other diabetic groups, group 6 (with 5% Yunnan baiyao) has better healing effect.

Heparin was covalently immobilized onto polyurethane surface via a PEG spacer by a microwave-assisted approach to improve blood compatibility. Firstly, amino-terminated poly(ethylene glycol) (APEG) was rapidly grafted onto PU surface within 20 min by a two-step method involving microwave-assisted MDI-functionalization and subsequent microwave-assisted APEG coupling. Then, heparin was covalently immobilized through an amide linkage by the direct coupling of the carboxylic acid of heparin with the amino group of APEG on PU surface using carbodiimide coupling reaction. The surface structure and properties were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and water contact angle measurements. The results revealed that heparin-immobilized PU surface had slightly increased roughness and significantly improved hydrophilicity in comparison to the original PU surface. The anticoagulant activity of films was evaluated by whole blood clotting time (CT) and prothrombin time (PT). Complement activation was assessed by detecting complement fragment 3a concentrations of serum exposed to the films. The results revealed that the microwave-assisted heparin-immobilized PU films had excellent antithrombogenicity and suppressed complement activation, indicating improved blood compatibility.

The rheological behavior of a low epoxy resin system-SR8100/SD8734 for RTM in aviation industry was studied with viscosity experiments. The dual-Arrhenius rheological model and the improved engineering viscosity model were introduced and compared with the experimental data. The results indicated that the viscosity in the earlier stage calculated by dual-Arrhenius model matched the experimental data. As rising to 400 m·Pas, the viscosity calculated by the improved engineering model was closer to the experimental data. The processing windows of the resin system for RTM were determined by combining the two models, which could predict the rheological behavior of the resin system in a more credible way. 30–45 °C was the optimum processing temperature.

To obtain water-insoluble silk fibroin (SF) materials, polyethylene glycol diglycidyl ether (PEG-DE) was selected as a crosslinking agent to prepare SF films (blends). The reaction conditions were optimized for the crosslinking of the SF molecules. The hot water stability of the blends was measured using BCA protein assay and gravimetric analysis. The molecular conformation and crystalline structure of the blends were analyzed by FTIR and XRD, respectively. When the mass ratio of SF:PEG-DE was 1.0:0.8, the hot water loss rate of the SF blends was minimized. PEG-DE could induce SF molecules to form β-sheets during the gel reaction process, resulting in improved crystallinity and hot water dissolved resistance of the blend films. In order to demonstrate the cytotoxicity of the chemical reagents used to crosslink SF, L929 cells were seeded on the blend film (SF:PEG-DE = 1:1) and cultured for 3 days. Cells of L929 readily adhered and spread in the fusiform on the blend film resulting in high cell viability. The extracted liquid from the SF porous film did not inhibit cell proliferation, as estimated by the MTT assay.

Several 1-vinyl-3-alkylimidazolium halogens [VRIM]X, which are functional materials with ethylenic bonds, were synthesized using the microwave-assisted synthesis method. Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance spectroscopy were carried out to analyze the resultant structures. The electrochemical properties and solubility of [VRIM]Br were investigated and discussed in detail. The temperature dependence of pure [VRIM]Br over a wide temperature range of 298.15–323.15 K fitted the Arrhenius equation well. At certain low concentrations, the electrical conductivity of the [VRIM]Br solution significantly increased with increasing solution concentration. The electrical conductivities of the [VRIM]Br observed in water, methanol, and ethanol showed the trend σ _water > σ _methanol > σ _ethanol. Conductometry showed that the critical micelle concentrations of the bromines in water, methanol, and ethanol were 6.8–6.9 × 10⁻⁶, 1.4–1.5 × 10⁻⁵, and 1.9–2.0×10⁻⁵ mol·L⁻¹, respectively; these results indicate that [VRIM]Br is an excellent surfactant. The solubility of [VRIM]X in common solvents was determined at 293.15 K, and results indicated that a decrease in solubility could be observed with decreasing dielectric constant of the solvent, elongation of the alkyl chain of the cation, and increasing anion size. Solubility parameters were also determined according to the Hildebrand-Scoff equation.