As pore-forming materials, the coated poly-p-hydroxybenzoate(short for PHB) and h-BN can be applied in the preparation of abradable seal coatings at high temperature. The characteristics of coating such as morphology, thermal stability and composition were studied by SEM, EDS and FTIR. The results show that the modified PHB will change the remained carbon amount, porosity and pore morphology of the coating, which can affect the properties of coatings. If the pore is small enough in uniform distribution, the coating with 5 MPa bond strength, 30–55 HR45Y superficial hardness and certain of carbon can be suitable to well abradability.

High-temperature thermal storage material is one of the critical materials of solar thermal power generation system. Andalusite, kaolin, talc, λ-Al₂O₃ and partially stabilized zirconia were used as the raw materials, and in-situ synthesis of cordierite was adopted to fabricate thermal storage material for solar thermal power generation via pressureless sintering. The phase compositions, microstructures and thermal shock resistances of the sintered samples were analyzed by XRD, SEM and EDS, and the corresponding mechanical properties were measured. The results show that the major phases of the samples are mullite and zirconium silicate, and the pores distribute uniformly. After being sintered at 1 460 °C, A4 sample exhibits a better mechanical performance and thermal shock resistance, its loss rate of bending strength after 30 cycles thermal shock is 3.04%, the bulk density and bending strength are 2.86 g·cm⁻³ and 139.66 MPa, respectively. The better thermal shock resistance of the sample is closely related to the effect of zirconium silicate, such as its uniform distribution, nested growth with mullite, low thermal expansion coefficient, high thermal conductivity, etc. This ceramic can be widely used as one of potential thermal storage materials of solar thermal power generation system.

ZnO thin films were deposited on graphite substrates by ultrasonic spray pyrolysis method with Zn(CH₃COO)₂·2H₂O aqueous solution as precursor. The crystalline structure, morphology, and optical properties of the as-grown ZnO films were investigated systematically as a function of deposition temperature and growth time. Near-band edge ultraviolet (UV) emission was observed in room temperature photoluminescence spectra for the optimized samples, yet the usually observed defect related deep level emissions were nearly undetectable, indicating that high optical quality ZnO thin films could be achieved via this ultrasonic spray pyrolysis method. Considering the features of transferable and low thermal resistance of the graphite substrates, the achievement will be of special interest for the development of high-power semiconductor devices with sufficient power durability.

Monoclinic metahewettite CaV₆O₁₆·3H₂O has been fabricated via thermal hydrolysis of calcium vanadate (Ca₁₀V₆O₂₅). High purity calcium vanadate precipitate, featuring column structure with surface area of 8.61 m²/g, can be obtained by reacting sodium orthovanadate (Na₃VO₄) with calcium oxide at 90 °C for 2 h. By acidification of calcium vanadate in hot water at pH of 1.0–3.0, the monoclinic metahewettite crystals with uniform particle distribution, layered structure and nonporous structure can be fabricated. With the well crystallized layered structure, CaV₆O₁₆·3H₂O may be a potential cathode material for secondary batteries as well as super capacitor materials.

The Zn_1−xCu _xO polycrystalline materials were prepared by doping CuO into wurtzite ZnO through solid state reaction. The high concentration of copper doping in ZnO exhibited remarkable room temperature ferromagnetism. The Experiments showed that the magnetization saturation rose with the increase of Cu content. For the low Cu content sample, the hysteresis loop was slightly tilted which indicated that the diamagnetism coexisted in this sample. The temperature dependence of magnetization of Zn_1−xCu _xO revealed that the magnetic exchange coupling depended on the doping concentration of Cu and there were many different local environments for magnetism. The measured hysteresis loop and temperature dependence of magnetization were overall performance of the magnetism coming from a wide distribution of ferromagnetic exchange couplings.

The chloride ion transmission model considering diffusion and convection was established respectively for different zones in concrete by analyzing chloride ion transmission mechanism under the drying-wetting cycles. The finite difference method was adopted to solve the model. The equation of chloride ion transmission model in the convection and diffusion zone of concrete was discreted by the group explicit scheme with right single point (GER method) and the equation in diffusion zone was discreted by FTCS difference scheme. According to relative humidity characteristics in concrete under drying-wetting cycles, the seepage velocity equation was formulated based on Kelvin Equation and Darcy’s Law. The time-variant equations of chloride ion concentration of concrete surface and the boundary surface of the convection and diffusion zone were established. Based on the software MATLAB the numerical calculation was carried out by using the model and basic material parameters from the experiments. The calculation of chloride ion concentration distribution in concrete is in good agreement with the drying-wetting cycles experiments. It can be shown that the chloride ion transmission model and the seepage velocity equation are reasonable and practical. Studies have shown that the chloride ion transmission in concrete considering convection and diffusion under the drying-wetting cycles is the better correlation with the actual situation than that only considering the diffusion.

We evaluated the cure behavior of multi-walled carbon nanotubes (MWCNTs) based thermally conductive adhesive by comprehensively thermal analysis, which presented extremely complicated variability of conversion ratio α as a function of temperature with synergistic action of positive effect and negative volumeblocking effect of MWCNTs and cross-linked network of cured polymer molecules. Due to the decomposition of MWCNTs and degradation of polymer, the mass drop is dramatically obvious over the temperature range of 330–370 °C. Binary resins filled with acid -treated MWCNTs present similar reaction interval as neat epoxy and matrix resins, which is distinct from the material filled with raw MWCNTs. The alteration of the crystalline temperature and cure temperature of resins is attributed to heterogeneous nucleation of MWCNTs in matrix resins. The -COOH group of acid-treated MWCNTs reacts with epoxy groups and thus generates cross-linking, accelerates the reaction rate and reduces the cure temperature.

Montmorillonite supported titanium (Ti-MMT) or antimony catalyst (Sb-MMT) has been a hot area of research on preparing polyethylene terephthalate/montmorillonite (PET/MMT) nanocomposites by in situ polymerization. So removal of Ti or Sb from Ti-MMT or Sb-MMT is not expected during in situ polymerization. Studies on immobilization of Ti or Sb on Ti-MMT or Sb-MMT are seldom reported. In this work, a series of montmorillonite supported catalysts of titanium (Ti-MMT) or antimony (Sb-MMT) and cointercalated montmorillonite of titanium and antimony (Ti/Sb-MMT) were prepared by (1) the reaction of sodium bentonite suspension with intercalating solution containing titanium tetrachloride and/or antimony chloride, and (2) drying or calcinating the products at different temperature (100, 150, 240, 350 and 450 °C). The physicochemical properties of these MMT supported catalysts were studied by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), inductively coupled plasma optical emission spectrometer (ICPOES), N2 adsorption/desorption isotherms, UV-visible diffuse reflectance spectroscopy(UV-vis) and transmission electron microscopy (TEM). The immobile character of Ti or Sb on MMT supported catalysts was evaluated by a two-step method in deionized water or ethylene glycol. Several results were obtained, i e, (a) during the preparation, with an increase in drying or calcinating temperature, the amount of titanium and/or antimony species remained on these MMT supported catalysts decreased, (b) the experiments about immobile character of Ti or/and Sb showed that with an increase in drying or calcinating temperature, the immobilization of Ti and/or Sb species remained on these MMT supported catalysts increased gradually, (c) Ti-MMT calcinated at 450 °C had the biggest pore volume, which means Ti-MMT had the best adsorption application prospect.

The thermal performance of nano fluid containing Ag NPs with different stabilizers was studied in detail. The wall temperature distributions of the heat pipe containing pure water and a small amount of PAN/Ag, PVP/Ag, L-cys/Ag, and OA/Ag were determined, respectively. With the addition of a small amount of Ag NPs in the pure water, the heat pipe wall temperature became lower than that of pipes filled with pure water. The efficiency under the same conditions was ranked as PVP/Ag > L-cys/Ag > PAN/Ag > OA/Ag. After adding a small amount of CNT in the mixture, the effect was enhanced further. As more CNT became dispersed in the working fluid, the opposite effect was observed. Therefore, the optimal amount is 4 mg/L CNT in nano-fluid. Ag nano fluid could form the multi-scaled surface with higher wettability and spreadability. The wettability of nano-fluid was improved with the addition of a small amount of CNT in the mixture. However, the spreadability of the mixture would decrease significantly in the presence of more CNT.

Polyaniline (PANI) composite nanotubes (90–130 nm in diameter) containing titanium dioxide (TiO₂) nanoparticles (about 10 nm in diameter) were synthesized through a self-assembly process in the presence of â-naphthalenesulfonic acid (â-NSA) as the dopant. It was found that PANI-TiO₂ composites and PANI nanotubes both behaved with significant photocatalytic activities towards AZO dyes, during 2 h photocatalytic processes under natural light, the degradation ratio was 94.2% and 97.2% respectively (methyl orange and orange II). The morphology of such products was characterized by SEM. The specific surface area of such composite nanotubes was 14.7 m²/g compared to normal polyaniline which was 0.27 m²/g. IR and X-ray diffraction characterizations showed that the chemical chain of the composite nanotubes was identical to that of the doped PANI. It may provide a new way for photodegradation of organic contaminants by using conjugated polymer with dimensional structure.

GeS₄ bulk glasses were prepared by the melt-quench technique and the samples were irradiated by 532-nm linearly polarized light. After the laser treatment, the photo-induced changes of the samples were investigated by UV-1601 spectrophotometer and optical second-order nonlinear tester. The results show that the transmittance of the samples around 532 nm obviously decreases and Bragg reflector forms, which is due to the production of photon-generated carriers. With the increase of laser pulse energy or the extension of irradiation duration, the Bragg reflector increases and gradually tends to be stable. These can be ascribed to the excitationcapture process of the carriers. After irradiation, the relaxation phenomenon results from the release of part of the absorbed energy in the glass matrix. And the fitting equation of the relaxation process is consistent with a conventional Kohlrausch stretched exponential function. The origin of the second harmonic generation (SHG) is because of the dipole reorientation caused by the photo-induced anisotropy in the glass.

An effective and reproducible preparation of silica sol nanospheres via a modified sol-gel process has been described. Monodisperse and stable silica sol nanospheres with uniformsize were successfully obtained through the optimized synthesis in which the mixture of tetraethyl orthosilicate (TEOS) and ethanol was followed by the addition of water and ammonium hydroxide (NH₃) separately, and the size of silica sol spheres was strictly controlled in the range of 25–119 nm with a narrow size distribution by fine adjustment of several reaction parameters. Results showed that in the presence of low concentration of TEOS, spheres size rose first and reached maximum when H₂O concentration was up to 66 g/L. However, the diameter of silica sol spheres decreased above 66 g/L of H₂O concentration. Furthermore, it was also found that the size and size distribution of silica sol nanospheres were affected by NH₃ concentration. As NH₃ concentration increased from 15 to 35 g/L, the diameter declined from 83 to 64 nm. Nevertheless, higher NH₃ concentration would result in relatively broad size distribution, and gelation occurred when NH₃ concentration reached 44 g/L. In addition, the effect of the different feed rates of NH₃ on the size growth of silica sol nanospheres was also discussed.

The single fiber fragmentation test (SFFT) was used to measure the interfacial shear strength (IFSS) of sized and unsized CF800/epoxy resin monofilament composite in order to evaluate the effect of sizing respectively. Besides, the interfacial reinforcing mechanism was explored by analyzing the surface morphology of the carbon fibers, the wettability between the carbon fibers and the epoxy resin, and the chemical characteristics of the fiber surface. Moreover, the effect of sizing on heat and humidity resistance of interface was investigated by aging test. The results show that sizing improves IFSS of CF800/epoxy resin monofilament composite by 59% through increasing the functional groups containing oxygen and through enhancing wettability, while after sizing the heat and humidity resistance of interface is decreased.

An energetic salt, sodium nitroformate (NaNF), was synthesized and characterized by elemental analysis, IR and UV spectra, and its crystal structure was first determined by single crystal X-ray diffraction. The structure exhibits two types of π-π stacking interactions between the nitroformate anions, i e, the parallel-displaced and T-shaped configurations. Furthermore, the thermal decomposition mechanism was investigated by DSC, TG-DTG and FTIR techniques. The kinetic parameters of the thermal decomposition were also calculated by using Kissinger’s and Ozawa-Doyle’s methods. The results show that NaNF has a good thermal stability, which is attributed to the π-π stacking interactions.

We researched the electric heating property from butyl rubber-loaded boron carbide composite. The effects of boron carbide content on bulk resistivity, voltage-current characteristic, thermal conductivity and thermal stability of boron carbide / butyl rubber (IIR) polymer composite were introduced. The analysis results indicated that the bulk resistivity decreased greatly with increasing boron carbide content, and when boron carbide content reached to 60%, the bulk resistivity achieved the minimum. Accordingly, electric heating behavior of the composite is strongly dependent on boron carbide content as well as applied voltage. The content of boron carbide was found to be effective in achieving high thermal conductivity in composite systems. The thermal conductivity of the composite material with added boron carbide was improved nearly 20 times than that of the pure IIR. The thermal stability test showed that, compared with pure IIR, the thermal stable time of composites was markedly extended, which indicated that the boron carbide can significantly improve the thermal stability of boron carbide / IIR composite.

The durability of silane-modified mortar, a cementitious composite, in acid rain environment was investigated given its extensive usage as a structural material. The results indicated that the addition of silane decreased the compressive strength of the cementitious composite. Wetting angle was increased by incorporating silane into the matrix. Decrease in both water absorption ability and coefficient of capillary suction confirmed hydrophobicity as induced by silane addition. Results of mechanical testing, scanning electron microscopy and X-ray diffraction showed that the sulfuric acid resistance of mortar was enhanced by silane. Based on these results, it is revealed that silane addition inhibits the diffusion of water, and consequently, sulfate ion diffusion rate decreases, thereby resulting in reduction in the rate of corrosion of cementitious composites by sulfuric acid.

The effects of polyacrylamide (PAM) and polyvinyl alcohol (PVA) on morphology and structure of calcium silicate hydrate with C/S 1.0–1.7 prepared via precipitation in solution were investigated by XRD, FT-IR and TEM techniques. The results show that incorporation of the polymers decreased the order degree, increased the interlayer spacing and disturbed the layered stacking of C-S-H. Interlayer spacing expansion depended on C/S ratios and type of polymer. Interlayer spacing expansion had a minimum at C/S 1.0 and a maximum at C/S 1.3 and 1.5. Interlayer spacing expansion of PAM was bigger than that of PVA with the same C/S. C-S-H added with PVA mainly exhibited foil-like and fibrillar morphology. The fibrils were of variable length from a few tens of nanometers to a few hundreds of nanometers. Fibrils or foils seemed to be longer in the presence of PVA.

Limestone in cement could be a source of CO₃ ²⁻ needed for thaumasite formation which will result in thaumasite form of sulfate attack (TSA) probably. TSA has more deterioration than ettringite or gypsum form of sulfate attack because it targets the calcium silicate hydrates (C-S-H) which is the main binder phase in all Portland cement-based materials. By means of physical and mechanical property testing as well as erosion phases analysis, magnesium sulfate attack of cement-based material containing 35% limestone powder by mass at 5 ± 2 °C is investigated. The compressive strength and flexural strength of mortar specimen immersed in MgSO₄ solution increase firstly, then decrease rapidly with the immersing age. Relative dynamic elastic modulus of mortar specimen changes in a phased process. After immersing in MgSO₄ solution for 15 weeks, the main erosion phases in paste specimen change from four phases compounds, three phases compounds to two phases compounds from surface to inside. Deterioration course of limestone cement-based material exposed to magnesium sulfate aggressive environment appears progressive damage layer by layer, and every layer probably suffers four stages, which are property strengthening stage, initial degradation stage, thaumasite formation stage and cementation loss stage, respectively.

To study the influence of multi-wall carbon nanotubes (MWCNTs) on the mechanical and microstructural properties of cementitious composites, 0.00, 0.02, 0.08, 0.10, and 0.20 wt% of multi-wall carbon nanotubes were added into cement mortar, in which the cement-sand ratio was 1:1.5. The flexural and compressive strengths of cement mortar at the age of 3, 7, 28 and 90 d and the fracture performance at the age of 28 d were determined, its 2D micrograph was tested by means of SEM, and the 3D defects distribution was firstly determined with or without CNTs by means of XCT (X-ray computerized tomography). The results showed that 0.08 wt% of CNTs improved the compressive strength and flexural strength by 18% and 19%, respectively, and a significant improvement of its fracture property was observed. Moreover lower addition of carbon nanotubes to cement mortars can improve its microstructure and decrease the defects significantly compared to the cement mortar without CNTs. With the increase of the content of CNTs, the mechanical properties of cement mortars presented to be declined largely due to the agglomeration of CNTs.

Defects of cement-based materials can be restored by microbial carbonate precipitation, but in order to accelerate the completion of the mineralization process, previous studies all adopt the approach of immersion in bacterial liquid, which can not be applied for in situ repair. We investigated micro-environment, basophil-domestication of microorganism and effective absorption of micro-organisms by cement-based materials, and adopted spray technology to conduct in situ repairs on the defects on the surface of cement-based materials and enhance the repair process operability. Through microbial carbonate precipitation in the defects by spraying bacteria liquid, 100 μm thickness of calcium carbonate film can be deposited on sample surface and in defects holes’ microenvironment within 3 to 5 days. The capillary water absorption coefficient of specimen surface is 77% lower than the value before repair. The repairing effect is remarkable which makes it possible to conduct on-site repairs.

In polymer modified cementitious materials, it is hard to set up a chemical connection between the added polymer and the cement moiety. In this study FS (functional silane) was adopted to form this connection as a bridge component which has the functional group forming bonds with polymer. To testify the connection between FS and cement moiety, Q ²/Q ¹ ratio (Q ^x: intensity ratio) investigation was carried out by the means of quantitative solid state 29Si MAS NMR. The results show that the Q ²/Q ¹ ratio has increased with the addition of FS which indicates that the silicon chain length has increased, and the quantity of silicon atoms at site of Q ², chain site, has enhanced, showing that the silicon atom of FS has connected to the silicon chain of cement moiety by the bond “-Si-O-Si-” formation.

The degradation mechanisms of cementitious materials exposed to sulfate solutions have been controversial, despite considerable research. In this paper, two methodologies of image analysis based on scanning electron microscope and chemical mapping are used to analyse Portland cement mortars exposed to sodium sulfate solution. The effects of sulfate concentration in solution and water to cement ratio of mortar, which are considered as the most sensitive factors to sulfate attack, are investigated respectively by comparing the macro expansion with microstructure analysis. It is found that the sulfate concentration in pore solution, expressed as sulfate content in C-S-H, plays a critical role on the supersaturation with respect to ettringite and so on the expansion force generated.

Recent achievements in concrete hydration exothermic models based on Arrhenius equation have improved computation accuracy for mass concrete temperature field. But the properties of the activation energy and the gas constant (E _a/R) have not been well studied yet. From the latest experiments it is shown that E _a/R obviously changes with the hydration degree without fixed form. In this paper, the relationship between hydration degree and E _a/R is studied and a new hydration exothermic model is proposed. With those achievements, the mass concrete temperature field with arbitrary boundary condition can be calculated more precisely.

The effect of curing regime on degree of Al³⁺ substituting for Si⁴⁺ (Al/Si ratio) in C-S-H gels of hardened Portland cement pastes was investigated by ²⁹Si magic angel spinning (MAS) nuclear magnetic resonance (NMR) with deconvolution technique. The curing regimes included the constant temperature (20, 40, 60 and 80 °C) and variable temperature (simulated internal temperature of mass concrete with 60 °C peak). The results indicate that constant temperature of 20 °C is beneficial to substitution of Al³⁺ for Si⁴⁺, and Al/Si ratio changes to be steady after 180 d. The increase of Al/Si ratio at 40 °C is less than that at 20 °C for 28 d. The other three regimes of high temperature increase Al/Si ratio only before 3 d, on the contrary to that from 3 to 28 d. However, the 20 °C curing stage from 28 to 180 d at variable temperature regime, is beneficial to the increase of Al/Si ratio which is still lower than that at constant temperature regime of 20 °C for the same age. A nonlinear relation exists between the Al/Si ratio and temperature variation or mean chain length (MCL) of C-S-H gels, furthermore, the amount of Al³⁺ which can occupy the bridging tetrahedra sites in C-S-H structure is insufficient in hardened Portland cement pastes.

Tributyl citrate (TBC) plasticizer has been selected to prepare the novel plasticized PC under different time and temperature. The TBC plasticization effect on PC T _g, mechanical properties and morphology has been investigated by DMTA, DSC, tensile test and SEM. The results show that the TBC content in PC is controlled by plasticization time and temperature. The mass-loss test has confirmed a less lost rate of TBC in PC. The T _g declines gradually with increasing TBC content. The tensile modulus and strength of the plasticized PC also decrease with the increase of TBC content, and an approximate linear relationship is found to exist between the TBC content and the tensile modulus and strength. The SEM images show that significant changes have taken place on the surface and in the cross-section of plasticized thin PC sheet.

A new kind of composite buffering material was made by filling the voids of honeycomb paperboard with polyurethane. Drop tests were performed to evaluate the dynamic energy absorption capacity of the material. Based on the tests results, we analyzed the mechanical behaviors of the material under different conditions and obtained the inherent influencing laws of some factors on the material’s dynamic buffering performance. It was shown that the dynamic buffering performance varied directly with impact velocity, and inversely with the void diameter, thickness and buffering area of the composite material.

A chemical system for facile and accurate detection of 2,4-dichlorophenol (DCP) via iron (II) phthalocyanine (Fe(II)Pc) catalyzed chromogenic reaction is reported for the first time. In this system, DCP could be oxidized by dioxygen with the catalysis of Fe(II)Pc and then coupled with 4-aminoantipyrine (4-AAP) to generate pink antipyrilquinoneimine dye. Control experiments showed that the addition of ethanol could obviously enhance the catalytic activity of heterogeneous Fe(II)Pc catalysts because of the partial dissolution of Fe(II)Pc nanocubes, which was confirmed by the SEM analysis. On the basis of the detection results of DCP in the range from 2×10⁻⁵ to 9×10⁻⁴ mol/L, we obtained a regression equation (A = 0.187 5 + 0.01 209C (R ²=0.995 6)) with the detection limit (3σ) of 3.26×10⁻⁶ mol/L, which could be successfully used in detecting the real samples.

The effect of fast cooling rate on the microstructure and mechanical properties of low-carbon high-strength steel annealed in the intercritical region was investigated using a Gleeble 1500 thermomechanical simulator and a continuous annealing thermomechanical simulator. The results showed that the microstructure consisted of ferrite and bainite as the main phases with a small amount of retained austenite and martensite islands at cooling rate of 5 and 50 °/s, respectively. Fast cooling after continuous annealing affected all constituents of the microstructure. The mechanical properties were improved considerably. Ultimate tensile strength (UTS) increased and total elongation (TEL) decreased with increasing cooling rate in all specimens. The specimen 1 at a cooling rate of 5 °/s exhibited the maximum TEL and UTS×TEL (20% and 27 200 MPa%, respectively) because of the competition between weakening by presence of the retained austenite plus the carbon indigence by carbide precipitation, and strengthening by martensitic islands and precipitation. The maximum UTS and YS (1 450 and 951 MPa, respectively) were obtained for specimen 2 at a cooling rate of 50 °/s. This is attributed to the effect of dispersion strengthening of finer martensite islands and the effect of precipitation strengthening of carbide precipitates.

The evolution of hardness homogeneity in commercially pure titanium processed by equal channel angular pressing (ECAP) for up to 4 passes following route C at room temperature using a die of 90°C was investigated by recording the microhardness on the cross-sectional and longitudinal planes of each billet. The results show that the hardness increases significantly after the first pass although there is a region of lower hardness on the cross-section running in a band near the bottom surface of the billet, and then increases by very small amounts in subsequent passes. With increasing numbers of passes, the lower hardness region near the bottom surface disappears and the microhardness values are distributed homogeneously throughout the cross-sectional and longitudinal planes after 4 passes of ECAP. The microhardness values in the central regions of the billet are slightly lower than those of the top and bottom surfaces. The results show that good homogeneity may be achieved throughout the billets after 4 passes of ECAP following route C.

Copper patinas are generally regarded as aesthetically pleasing and are supposed to protect copper against further corrosion. The preparation of artificial sulphate patina on bronzes has been realized by immersing the bronze into CuSO₄ solution. The effect of immersion time on the formation of the patina has been investigated. The sulphate patina obtained with immersion time of 500 h in CuSO₄ solution consists of flat area and crystals. The flat area in the patina is mainly made of cuprite, whereas the crystals are mainly composed of brochantite. The electrochemical measurement of sulphate patina in simulated acid rain with pH 3.1 shows that the protective effectiveness of patina decreases with time and the dissolution of patina is the key factor leading to the degradation of patina. The investigation of the formation mechanism of sulphate patina shows that the cuprite layer forms on the surface of bronze in the initial patination. Then, crystal brochantite grows on the surface of cuprite by the oxidation of cuprite and the incorporation of CuSO₄ solution.

Plasma nitriding was used to improve the corrosion performance of anchor steel. The microstructure, phase constitution, microhardness and corrosion resistance of the nitrided layer were systematically studied. The results show that the nitrided layer is continuous and dense, and consists of Fe₄N and Fe₃N in the outmost surface. The microhardness of the nitrided sample is improved because of the formation of nitrides in the outer side continuous layer and the inner parts. The nitrided layer on the surface of anchor steel can effectively improve the corrosion resistance of the anchor steel.

To investigate the transformation behavior of TRIP steel retained austenite under cyclic load, cyclic V-bending deformation of low carbon Si-Mn TRIP600 was studied by experiment and finite element in this paper. The results showed that, under cyclic V-bending deformation, retained austenite in TRIP steel transformed into martensite gradually with the increasing of bending times, and for the symmetrical characteristic, upper surface and lower surface presented the same transformation tendency. From the first to the fourth V-bending deformation, retained austenite volume fraction decreased nearly linearly and then attained saturation step by step. Compressive stress state was helpful for martensite transformation than tension stress state with V-bending deformation, and strain magnitude was the determining factor for retaining austenite martensitic transformation. With the increasing of bending times effective stress increased and the relationship between maximum effective stress and bending times was nearly linear. Effective stress and effective strain distribution were non-uniform, the maximum effective stress and effective strain were present in the center of the samples. The relationships between retained austenite and V-bending times, and retained austenite with effective strain were set up as Eqs.(1)–(5). The relationship was typical quadric function, decreased linearly for the initial deformation and attained saturation finally.

Hot compression tests of low carbon steel were carried out on Gleeble-3500 system in the temperature range from 750 to 900 °C and in the strain rate range from 0.001 to 1.0 s⁻¹, and the associated microstructural evolution was studied by observations with a metallographic microscope. The results show that the stress-strain curves exhibit a peak stress at critical strain, after which the flow stresses decrease monotonically until reaching high strains, showing a dynamic flow softening. The peak stress level decreases with increasing deformation temperature and decreasing strain rate, which can be represented by the Zener-Hollomon parameter Z in the hyperbolic sine equation. The flow stress increases with increasing strain rate and decreasing deforming temperature. The flow stress can be described by constitutive equation in hyperbolic sine function and can also be described by a Zener-Hollomon parameter Z. With increasing deformation temperature and decreasing strain rate, the grain size as well as the volume fraction of the recrystallized grains increase. The safe region for hot working of the alloy has been determined according to the processing map and microstructure at the true strain of 0.5, which is the deformation temperature of 840–940 °C and the strain rate of 0.001–1.0 s⁻¹.

Copper-nickel nanoparticle was directly prepared by flow-levitation method (FL) and sintered by vacuum sintering of powder (VSP) method. Several characterizations, such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), differential thermal analysis (DTA), and energy-dispersive X-ray spectroscopy (EDX) were used to investigate the prepared nanostructures. The results of the study show that flmethod could prepare high purity Cu-Ni nanocrystals of uniform spheres with size distribution between 20 and 90 nm. After sintering the bulk nanocrystalline copper-nickel has obvious thermal stability and the surface Webster hardness increases with the rising sintering temperature. At the temperature of 900 °C, the specimen shows higher surface Webster hardness, which is about two times of traditional materials. When the sintering temperature arrives at 1 000 °C the relative density of bulk nanocrystals can reach 97.86 percent. In this paper, the variation tendency of porosity, phase and particles size of bulk along with the changing of sintering temperature have been studied.

Mg films of various thicknesses were deposited on Si(111) substrates at room temperature by resistive thermal evaporation method, and then the Mg/Si samples were annealed at 40 °C for 4 h. The effects of Mg film thickness on the formation and structure of Mg₂Si films were investigated. The results showed that the crystallization quality of Mg₂Si films was strongly influenced by the thickness of Mg film. The XRD peak intensity of Mg₂Si (220) gradually increased initially and then decreased with increasing Mg film thickness. The XRD peak intensity of Mg₂Si (220) reached its maximum when the Mg film of 380 nm was used. The thickness of the Mg₂Si film annealed at 400 °C for 4 h was approximately 3 times of the Mg film.

To explore the effect of strontium on the structure of as-cast A356 alloy, the strontium was incorporated to the alloy by metallothermic reduction of SrO where the mineral was added to the melt through the submerged powders injection technique. The evaluation of the modification of the eutectic silicon and the chemical analysis of samples were done using optical microscopy (OP) and inductively coupled plasma (ICP), respectively, while microstructural analyses by scanning electron microscopy (SEM), and the injection time was variable. Magnesium was added to the melt to increase the reactivity and reduce the surface tension of the molten aluminum. It was possible to increase the strontium content from 0 to 0.027% after 20 minutes treatment. This concentration was sufficient to bring about full modification structure of eutectic silicon of as cast alloy A 356 and the acceptable quality metallurgical of alloy.

Schwann cells play a key role in peripheral nerve growth and regeneration. The aim of this study was to evaluate the effects of RGD peptides on Schwann cell behavior, and to identify the effects of the modified PDLLA films with RGD in vivo. The results revealed that RGD coating with the concentration of 100–500 ug/mL promoted the cell proliferation and boosted the cell migration. Molecularly, RGD coating also enhanced the expression of the proliferation related genes (c-fos and c-jun) and the cell behavior related genes (actin, tublin, tau and MAP1) at first stages of the seeding, which is similar to the effects from laminin coating. In vivo, RGD addition improved the recovery efficiency of the transected nerve in regard of the more survived Schwann cells in vivo and the formation of more mature myelin sheath. Taken together, RGD peptides are good candidates to enhance the biocompatibility of the biomaterials and facilitate the peripheral nerve regeneration by prompting responses in Schwann cells.

The arginine-glycine-aspartic (RGD) acid peptide was grafted to the surface of apatite-wollastonite (AW) ceramic in an effort to improve its cell adhesion, proliferation and osteoinduction. RGD peptide was covalently immobilized onto the surface of AW ceramic via the synthetic cross linker AAPTS-E and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC). The modified surfaces were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The chemical analysis indicated that RGD peptide had been immobilized onto the AW surface successfully. The growth of osteoblast-like cells (MG63) showed that modifying the AW surface with RGD peptide enhanced the cell adhesion and proliferation. And the histological evaluation of RGD-AW showed that the bone regeneration and remodeling process were significantly enhanced compared to the original AW ceramics after 2, 4 and 8 weeks implantation in rabbit’s femoral condyles.

To gain a better understanding of the anticancer effects of hydroxyapatite (HAP) nanoparticles in vivo and in vitro, the effects of the interaction of HAP nanoparticles with hepatoma cells were explored. HAP nanoparticles were prepared by homogeneous precipitation and characterized by laser particle analysis and transmission electron microscopy (TEM). HAP nanoparticles were observed to be uniformly distributed, with rod-like shapes and diameters in the range of 42.1–87.1 nm. Overnight attached, suspended, and proliferating Bel-7402 cells were incubated with HAP nanoparticles. Inverted microscopy observation revealed that HAP nanoparticles with a cell membrane showed good adsorption. TEM demonstrated that HAP nanoparticles were present on the surface of cells, continuously taken up by cells through endocytosis, and transported in vesicles close to the nucleus. Fluorescence microscopy showed that the concentrations of intracellular Ca²⁺ labeled with Fluo-3 calcium fluorescent probe were significantly enhanced. In addition, inverted microscopy observation revealed that suspended cells treated with HAP nanoparticles did not adhere to the culture bottle, resulting in cell death. After the overnight attached cells were treated with HAP nanoparticles for 96 h with increasing doses of HAP nanoparticles, inverted microscopy observation revealed that cell proliferation was slowed and cell-cell adhesion was weakened. Feulgen staining and image analysis indicated that the nuclear DNA content of the cells was markedly reduced, and argyrophilic nucleolar organizer region (AgNOR) staining and image analysis indicated that the number of AgNORs was significantly decreased. Therefore, hepatoma cells brought about the adsorption, uptake, transport and degradation of HAP nanoparticles. In addition, HAP nanoparticles affected hepatoma cells with regard to cell-cell adhesion, cell and extracellular matrix adhesion, and DNA and protein synthesis; thus inhibiting cell proliferation. This understanding of the effects of interaction between HAP nanoparticles and hepatoma cells is useful for further study of the anticancer mechanisms of HAP nanoparticles.