We derived revised effective diffusion energy barriers following the Boltzmann distribution assumption for impurity atoms in a bulk material under the impact of various kinds of point defects to reveal the insights of migration mechanisms. The effective diffusion energy barriers of copper impurities in bulk zirconium were calculated through the first principle method under the presented hypothesis. Our results (ΔE _|| =1.27 eV, ΔE _⊥=1.31 eV) agreed well with the experimental results (ΔE _|| =1.54 eV, ΔE _⊥=1.60 eV), which validated bulk diffusion as the major mechanism for copper diffusion in zirconium. The effective diffusion energy barriers could be used for estimating whether the defects will accelerate the diffusion or slow them down by acting as traps of the impurity atoms. On the other hand, the first principle results of the impurity diffusion via defects could be further used as inputs of larger scale computational simulations, such as MC (Monte Carlo) or Phase Field calculations.

The regular distribution of micro-droplets splitting from thin ferrofluid layer is systematic experimentally investigated, as the layer is placed in a vertical magnetic field. In this work, the field is applied in an instant manner and a slow manner, respectively; the field strength is linear increased. With instantly raising the field, it is observed that the ferrofluid layer is split into several regularly distributed micro-droplets, and that the number of micro-droplets is linear to the magnetic field strength and the thickness of the liquid layers. When the field is slowly increased, a liquid ring together with several micro-droplets appears from the ferrofluid layer splitting. A spatial drift of the micro-droplets is also observed in the process of increasing the magnetic field. Our results are useful for manipulating the splitting regularities of ferrofluid layers by magnetic field, which may be used in non-contact segmentation, and magnetically manipulated drug carriers for targeting the therapy, etc.

A molecular structural mechanics approach combining with finite element analysis (MSM/ FEA) was applied to study the microstructure and tensile behaviors of bamboo-like carbon nanotubes (BCNTs). The mathematical model of tensile behaviors of BCNTs was established based on molecular structural mechanics theory. The deformations of BCNTs, with different diameters and compartments set based on the experimental investigation on BCNT structures synthesized by chemical vapor depositon, under tensile load, were analyzed with ANSYS programmed. Results show that the BCNTs have good tensile properties, and those Young’s modulus can reach 0.84 Tpa. Through the analysis, it can be found that the Young’s modulus of BCNTs depends on the diameters and the length of compartment, which is in good agreement with our experimental tests for the tensile performances of individual BCNT.

Tungsten doped (W-doped) TiO₂ mesoporous nanobeads, possessing high surface area and superior scattering effect, were used for photoanode preparation. The W-doping would induce a positive shift of the TiO₂ conduction band, and enhance the driving force for electron injection and collection efficiencies. The electrochemical impedance spectra indicated a retarded charge recombination and increased electron diffusion length after W-doping. By fine-tuning the W-doping concentration to 0.25%, aqueous DSCs produced a significant improved the open circuit voltage of 712 mV and a short circuit current of 7.05 mA·cm^-2, leading to an overall increased power conversion efficiency of 3.40% at 1 000 W·m^-2 simulated irradiation, which is roughly 25% enhancement compared to that without W-doping photoanode.

MoS₂-decorated C₃N₄ (C₃N₄/MoS₂) nanosheets hybrid photocatalysts were prepared by a simple sonication-impregnation method. Face-to-face lamellar heterojunctions were well established between two dimension (2D) C₃N₄ and MoS₂ nanosheets. The effects of MoS₂ content on the light absorption, charge transfer and photocatalytic activity of the hybrid samples were investigated. Characterization results show that MoS₂ nanosheets are well anchored on the face of C₃N₄ nanosheets and the composites have well dispersed layered morphology. After loading with MoS₂, the light absorption of composites was much improved, especially in visible-light region. The photocatalytic activities of C₃N₄/MoS₂ samples were evaluated based on the H₂ evolution under visible light irradiation (λ > 400 nm). When the loading amount of MoS₂ was increased to 5 wt%, the highest H₂ evolution rate (274 μmol·g^-1·h^-1) was obtained. Compared with samples obtained from direct impregnation method, sonication pretreatment is favorable for the formation of 2D layered heterojuctions and thus improve the photocatalytic activity. Slightly deactivation of C₃N₄/MoS₂ composites could be observed when recycled due to the mild photocorrosion of MoS₂. Based on the band alignments of C₃N₄ and MoS₂, a possible photocatalytic mechanism was discussed, where MoS₂ could efficiently promote the separation of the photogenerated carriers of C₃N₄.

The K _xNa_(1-x)NbO₃ (x = 0.45, 0.46, 0.47, 0.48, 0.49, 0.50) lead-free piezoelectric ceramics was fabricated by conventional solid-state sintering method. It was found that the ratio of alkaline metal would affect the microstructure, bulk density, and optimum sintering temperatures of ceramics. Meanwhile, the electrical properties were also influenced by modulating the K/Na ratio, exhibiting corresponding composition-dependent properties. The optimum electrical properties of K _xNa_(1-x)NbO₃ such as piezoelectric constant d ₃₃ = 115 pC/N, mechanical quality factor Q _m = 20, Curie temperature T _c = 365 °C, ε ^T ₃₃/ε₀= 588.1, dielectric loss tan δ = 0.024, bulk density (ρ) = 3.08 g/cm³, remnant polarization (P _r) = 8.87 μC/cm² and coercive field (E _c) = 13.79 kV/cm were obtained at x = 0.46.

A facile deposition method has been developed for large-scale synthesis of visible-light-driven AgBr/montmorillonite composite catalyst for the first time. The as-synthesized samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and Brunauer-Emmett-Teller (BET) surface area analysis, respectively. Through the combined action of adsorption and photodegradation, the as-prepared AgBr/montmorillonite composite exhibited a higher removal efficiency for rhodamine B (RhB) than that of Na-montmorillonite and AgBr. For the methyl orange (MO) removal, the AgBr/montmorillonite composite possessed a superior photocatalytic performance compared with Namontmorillonite and AgBr. The enhanced photocatalytic activity of AgBr/montmorillonite composite can be attributed to the effective separation of the electron-hole pairs. In AgBr/montmorillonite suspension, the superoxide radicals are the main reactive oxygen species for dye degradation under visible light illumination.

Toxic Cu(II) and Ni(II) ions in aqueous solutions were adsorbed by microporous activated carbon (AC). The adsorption isotherm and kinetics correlation coefficients indicate that the adsorption of Cu(II) and Ni(II) ions on the AC fits the pseudo second-order rate model and Langmuir adsorption model. The used AC adsorbents containing the adsorbed Cu and Ni ions were used as colorant in glass preparation. The coloration effect of Cu ions was influenced by the carbon absorbent included in the glass batch due to the reduction phenomenon, while the coloration of Ni ions was not affected.

Magnesium ion-exchanged a-zirconium phosphates (Mg-α-ZrP) with particle sizes of 600 and 80 nm were prepared through the sealed ion-exchange and one-step hydrothermal synthesis methods, respectively. It was found that larger particles of Mg-α-ZrP had a higher load-carrying capacity than that of smaller particles, whereas smaller Mg-α-ZrP particles had better anti-wear properties than that of larger Mg-α- ZrP particles under mild loads. The correlation between the particle size of the sample and the surface roughness of the friction pair thus seems to be a key factor influencing the performance.

TiO₂ nanopowders with different nitrogen (N) dopant concentrations were first synthesized by sol-gel method. XRD, TEM, HRTEM, XPS, UV-vis DRS were used to characterize the effects of N doping on the microstructures and optical properties of TiO₂. The results indicated that the prepared TiO₂ only contained anatase phase with a slight distortion, and the N doping improved the dispersity of TiO₂. The N doping leaded to more defects in TiO₂, capturing the charge carriers and inhibiting the combination of electrons and holes. Also, the N-doped TiO₂ was composed of Ti, O and N. Further, N was doped into the TiO₂ lattice by substituting for O, forming the oxidized nitrogen in the form of Ti–N–O or Ti–O–N bond, and Ti was present in the form of Ti⁴⁺ in TiO₂. Finally, the absorbance of N-doped TiO₂ was obviously improved in both UV and visible light region. Optical absorption edges of N-doped TiO₂ samples showed obvious red shift, which expanded spectral absorption range of TiO₂ and improved the utilization efficiency of visible light. It is concluded that N element was successfully doped into TiO₂ crystal lattice, and the N dopant concentration of 3.0% was designed to modify TiO₂.

The electronic structure and the magnetic properties of Fe₂Si bulk have been calculated by the first-principle density function theory method. The band structure shows that the hexagonal Fe₂Si bulk is ferromagnetic which is a metal structure under spin-up, and a semiconductor with the band gap of 0.518 eV under spin-down. The density of states shows the Fe¹ 3d–spin and Fe³ 3d–spin in the electronic system are the main factors that is the source of the ferromagnetic properties of Fe₂Si bulk. The electronic structure Si-ions is 3s ² 3p ⁶ and that of Fe-ions is e _g ²↑e _g ^*1↓t _2g ³↑. The molecular magnetic moment of Fe₂Si is 2.00 μB. The potential diagram of Fe₂Si bulk shows the formation of covalent and ionic bonds between the Fe atom and the Si atom, it leads to the center charge of Fe is polarized and off center position. These special properties of Fe₂Si bulk are mainly caused by d-d exchange and p-d hybridization. The results offer a certain reference for the magnetic semiconductor Fe₂Si material.

To improve both oxygen evolution efficiency and stability at high temperatures, Mn, Mn+Mo, Mn+Mo+V, and Mn+Fe+V oxide electrodes were prepared on a Ti substrate, with an intermediate layer of IrO₂, by an anodic deposition method. The crystal structure, surface morphology, pore size distribution, specific surface area, and voltammetric charge were then characterized for each electrode. The results demonstrated that for Mn-O electrodes, the preferential orientation of the (100) crystal plane and the mesopore structure played negative roles in the oxygen evolution reaction. On the basis of the electrocatalytic properties of MnO₂- based electrodes in seawater, the outer surface voltammetric charge at a scan rate of 500 mV·s⁻¹ was shown to effectively indicate whether oxygen evolution reactions were preferred over chlorine evolution reactions. The Mn-O electrode exhibited oxygen evolution efficiency of only 47.27%, whereas the Mn+Mo, Mn+Mo+V and Mn+Fe+V oxide electrodes displayed oxygen evolution efficiency of nearly 100%. This means that adding Mo, V, and Fe elements to the electrode can improve its crystal structure and morphology as well as further enhancing its oxygen evolution efficiency.

To verify the effect of Al₂O₃ particle content and size as an abrasive on resin matrix friction materials for mining equipment, the tribological performance of friction materials was studied by using a blockon- ring tribotester over a wide range of applied load and sliding speed. The testing conditions simulated brake conditions of mining equipment. The antiwear property of nano-Al₂O₃ was superior to that of micro- Al₂O₃ for friction materials. The friction coefficients of specimens increased with the increase of nano-Al₂O₃ content. The wear rates decreased with increasing nano-Al₂O₃ content. The wear rates of specimens containing nano-Al₂O₃ was about 2–8 times lower than that of specimen with micro-Al₂O₃. The specimen with 10.5 vol% nano-Al₂O₃ showed the best tribological properties. The wear mechanism of specimens with nano-Al₂O₃ was abrasive wear and plastic deformation.

Ti, Al, graphite and diamond powders were used as raw materials to prepare Ti₂AlC matrixbonded diamond composite using self-propagating high-temperature synthesis (SHS) method. The effect of diamond size and content on the fabrication of Ti₂AlC-bonded diamond material was investigated. Results showed that Ti₂AlC matrix-bonded diamond composites could be obtained by SHS. The phase composition and microstructure of the Ti₂AlC-bonded diamond material were influenced by the diamond content and size. When the diamond (93 μm) additive amounts were 10% and 20%, the product phases included Ti₂AlC, TiC and Al3Ti. However, excess Ti and Al persisted in the sample that contained 30% diamond. Diamond bonded well with the matrix in the sample that contained 10% diamond. Moreover, addition of coarse diamond particles with sizes of 93 and 125 μm produced a mainly Ti₂AlC matrix. However, diamond adequately reacted with Ti to form TiC when finer diamond particles (5 and 10 μm) were used.

Non-spherical colloidal silica nanoparticle was prepared by a simple new method, and its particle size distribution and shape morphology were characterized by dynamic light scattering (DLS) and the Focus Ion Beam (FIB) system. This kind of novel colloidal silica particles can be well used in chemical mechanical polishing (CMP) of sapphire wafer surface. And the polishing test proves that non-spherical colloidal silica slurry shows much higher material removal rate (MRR) with higher coefficient of friction (COF) when compared to traditional large spherical colloidal silica slurry with particle size 80 nm by DLS. Besides, sapphire wafer polished by non-spherical abrasive also has a good surface roughness of 0.460 6 nm. Therefore, non-spherical colloidal silica has shown great potential in the CMP field because of its higher MRR and better surface roughness.

A simulation study was carried out by using dissipative particle dynamics (DPD) method to explore the effects of properties of coating chains, such as length, density, rigidity of polymer chains, as well as the distance between nanoparticles on bonding reaction of coating chains grafted onto nanoparticles. The results show that bonding ratios of coated chains strongly depend on the length and density of coating chains. For nanoparticles with different coating densities, the optimum chain length for bonding reaction are varied. The rigidity of coating chains exhibits vigorous effects on bonding reaction that highly depends on chain lengths. DPD simulation can be used to study the bonding reaction between coated nanoparticles, which may help experimental synthesis of nanocomposites with excellent properties.

The physical and mechanical properties of self-compacting geopolymer concrete (SCGC) using chemically synthesized nano-geopolymer cement was investigated. Nano-geopolymer cement was synthesized using nano-silica, alkali activator, and sodium aluminate in the laboratory. Subsequently, nine nanogeopolymer cement sbased SCGC mixes with varying nano-geopolymer cement content, alkali activator content, coarse aggregate (CA) content, and curing temperature were produced. The workability-related fresh properties were assessed through slump flow diameter and slump flow rate measurements. Mechanical performances were evaluated through compressive strength, splitting tensile strength, and modulus of elasticity measurements. In addition, rapid chloride penetration test, water absorption, and porosity tests were also performed. It was assessed that all mix design parameters influenced the fresh and hardened properties of SCGC mixes. Based on test results, it was deduced that nano-geopolymer cement SCGC performed fairly well. All the SCGC mixes achieved the 28-day compressive strength in the range of 60–80 MPa. Additionally, all mixes attained 60% of their 28-day strength during the first three days of elevated temperature curing. FTIR and SEM analyses were performed to evaluate the degree of polymerization and the microstructure respectively for SCGC mixes.

Influences of alkali oxides doping on the crystal structure, defects and hydration behavior of tricalcium silicate C₃S were investigated by X-ray powder diffraction with the Rietveld method, inductively coupled plasma optical emission spectroscopy, thermoluminescence and isothermal calorimetry. All the samples were stabilized as T1 form C₃S. Changes in the crystal structure of C₃S could mainly be monitored by changes in lattice parameters, which were closely correlated with the incorporation concentration and substitution types of alkalis. Although alkalis were incorporated at trace level in C₃S, the thermoluminescence and hydration behavior of C₃S were significantly influenced. Initial hydration activity was dramatically increased and highly related to the intensity of the irradiation-induced thermoluminescence peaks at low temperatures due to their direct correlation with defects. The oxygen vacancy sites resulting from the substitution of alkalis for Ca could readily account for the acceleration of the initial hydration of C₃S.

In order to consume the Yellow River sediment as much as possible and improve the longterm stability of the Yellow River, Yellow River sediment was utilized as the main raw material to produce a composite material. Ca(OH)₂ was used as alkali-activator to activate the active SiO₂ and Al₂O₃ compositions in Yellow River sediment. 10 wt% slag was added into the mixture to further improve the strength of the composites. The effect of activity rate of the Yellow River sediment and dosage of Ca(OH)₂ on the compressive strength of the Yellow River sediment-slag composite material at different curing ages was researched. XRD, SEM/ EDS, light microscope and FTIR were used to further explore the products and the microstructure of the composite material. Results showed that the active ratio of sediment had a great influence on the compressive strength of specimen. In addition, the compressive strength of specimen increased with the increase of Ca(OH)₂ dosage and curing age. When the dosage of Ca(OH)₂ was more than 5 wt% as well as the curing age reached 90 days, the compressive strength of the composite material could meet the engineering requirement. In the alkali-activated process, the main product was hydrated calcium silicate (C-S-H) gel, which filled up the gaps among the sediment particles and decreased the porosity of the specimen. Moreover, the CaCO₃ produced by the carbonization of the C-S-H gel and excess Ca(OH)₂ also played a role on the strength.

The present work presents the microstructure of β-Ca₂SiO₄ (β-C₂S) after accelerated carbonation. The synthesis procedure of β-C₂S was examined first, and the crystalline and amorphous structure, the distribution and the pore structure of β-C₂S carbonation products were also determined by X-ray diffraction (XRD) quantitative analysis, simultaneous thermal analyzer (TG/DTA), Fourier transform-infrared spectroscopy (FT-IR), high resolution ²⁹Si magic angle spinning nuclear magnetic resonance (29Si NMR), N₂-sorption techniques, and scanning electron microscopy (SEM), respectively. Test results indicate that carbonation products are dramatically formed in the initial 2 h. The main carbonation products are crystalline calcite and amorphous three-dimensional network silica gels, which contain nanometer-sized pores. The calcite, silica gels and un-carbonated β-C₂S are distributed hierarchically.

To evaluate the property and degradation characteristics of concrete prepared with aggregate contained montmorillonite, concretes were prepared with aggregates contained montmorillonite, and then concrete slump loss, compressive strength, electric flux, the resistance to carbonization, freezing-thawing and sulfate attack were evaluated. The results show that montmorillonite appearance alters concrete slump loss and compressive strength. But montmorillonite increases electric flux and compactness. The carbonization, freezingthawing and sulfate attack results indicate that montmorillonite enhances carbonization depth, increases mass loss after 300 cycle freezing-thawing, as well as mass loss after sulfate attack. Overall, it is adverse to the concrete resistance to the carbonization, freezing-thawing and sulfate attack.

2198 and 5A90 Al-Li alloys were anodized with a constant DC potential in 18%H₂SO₄ solution (Solu.A) and the mixture solution of 18%H₂SO₄+5%C₂H₂O₄ (Solu.B) at room temperature. 12 and 11 V was optimized as the applied oxidation potential for 2198 and 5A90 alloys, respectively. Cross-sectional morphology, surface morphology and elements distribution of anodic oxidation coatings were observed by scanning electron microscope equipped with energy dispersive X-ray analysis (SEM/EDX). Corrosion resistance was tested by potentiodynamic polarization plot in 3.5%NaCl solution. The results showed that the thicknesses of coatings obtained at the selected potential in Solu.A and Solu.B were about 50 μm/110 μm for 2198 alloy and 80 μm/110 μm for 5A90 alloy. In both solutions, anodic oxidation coatings of 2198 alloy were primarily composed of Al oxides; those of 5A90 alloy were mainly consisted of Al oxides and a small amount of Mg oxides. The results of potentiodynamic polarization showed that anodic oxidation coatings of 2198 and 5A90 Al-Li alloys had better corrosion resistances than that of untreated alloys.

Three as-cast and as-extruded Mg-5Zn-xY-0.6Zr (x=5 wt%, 8 wt%, 11 wt%) alloys were prepared, and the effects of Y content on the microstructures and mechanical properties of the alloys were investigated. The results show that the investigated Mg-Zn-Y-Zr alloys mainly consist of α-Mg, X-Mg₁₂YZn and minor amount of W-Mg₃Y₂Zn₃ phases. The volume fraction of X-Mg₁₂YZn phase increases and that of W-Mg₃Y₂Zn₃ phase decreases with the rising of Y content in the alloys. The as-extruded Mg-5Zn-11Y-0.6Zr alloy owns the optimal ultimate tensile strength and yield strength of 429 and 351 MPa, respectively. Mg-5Zn-5Y-0.6Zr alloy owns the maximum elongation of 13.6%.

Long (15 - 40 μm), thin (diameter of 20 ± 5 nm), and well-dispersed CuNWs Cu nanowires were prepared. The high-resolution TEM and selected area electron diffraction showed that the CuNWs were single-crystalline. To investigate the growth mechanism, we examined the microstructure of these CuNWs at different reaction time. It was found that the CuNWs were actually formed through the self-assembling of Cu nanoparticles along the [110] direction. The transparent electrodes fabricated using the CuNWs achieved a high transparency of 76 % at 31±5 Ω/□.

Mg-6Zn-xCe (x = 0, 0.6, 1.0, 2.0) alloy ingots with diameter of 50 mm were extruded into bars with diameter of 12 mm at 300 °C. The microstructures were analyzed by X-ray diffraction, optical microscopy, scanning electron microscopy and transmission electron microscopy, and mechanical properties were tested at room temperature. The results showed that major intermetallic composition in as-cast Mg-6Zn and Mg-6Zn-0.6Ce alloys was Mg₄Zn₇ phase, during extrusion Mg₄Zn₇ phase was dissolved into matrix and then precipitated as MgZn₂. In as-cast and as-extruded Mg-6Zn-1Ce and Mg-6Zn-2Ce alloys the major intermetallic composition was T phase. The microstructure of as-extruded alloy was refined due to complete dynamic recrystallization, the average grain size decreased with increasing Ce content, which were 12.1, 11.7, 11.0 and 10.0 mm, respectively. High density MgZn₂ precipitated in Mg-6Zn and Mg-6Zn-0.6Ce alloys. The broken T phase particles were distributed linearly along extrusion direction. Mg-6Zn-0.6Ce alloy exhibited a high yield strength of 226.3 MPa that was about 24 MPa higher than Mg-6Zn alloy. However, with increasing Ce contents, the strengths were decreased slightly because the effects of precipitation strengthening of MgZn₂ and solid solute strengthening of Zn were weakened though the strengthening effect of T phase was enhanced.

PEO ceramic coatings including ZrO₂-Al₂O₃-SiO₂ in three phases were prepared on an Al- 12.5%Si alloy in electrolyte solutions containing ZrO₂ nanoparticles. The microstructures and phases of the coatings were analyzed by SEM and XRD, and the heat insulation performance and the thermal shock resistance of the coatings were investigated. The compactness of the coating increased significantly and the hindrance of the Si element on plasma electrolytic oxidation process was effectively weakened. The growth rate of the coating was improved substantially with the addition of ZrO₂ nanoparticles. The PEO ceramic coatings are primarily composed of SiO₂ and high temperature steady phases such as α-Al₂O₃ and c-ZrO₂. Both the content of c-ZrO₂ and the heat-insulating property of the coating increased significantly. The ceramic coatings with special microstructure and composition formed in the solutions containing ZrO₂ nanoparticles possess excellent heat insulation performance and thermal shock resistance

The formation and growth behavior of intermetallic compound (IMC) layers after introducing an electroless Ni-W-P metallization into the Sn-3.0Ag-0.5Cu (SAC305) solder joint during soldering and aging were investigated. The soldering was performed at 250 °C for 10 min, followed by air cooling and aging treatment at 150 °C up to 15 days. The results show that the scallop-like Cu₆Sn₅ IMC layer and planar-like Cu₃Sn formed between solder and Cu substrate during soldering and aging. The Ni₃P and (Ni,Cu)₃Sn₄ compounds were formed between electroless Ni-W-P layer and solder, and Cu substrate was not damaged and kept a smooth interface. When the isothermal aging treatment was applied, the total thickness of IMCs which formed at the SAC₃0₅/Cu and SAC₃0₅/Ni-W-P/Cu interface increased with increasing aging time. Kirkendall voids emerged at the Cu₃Sn and the Ni₃P layers, but the voids emerged at the Ni₃P layer in the form of crack. The amount of Kirkendall voids increased and the crack elongated with increasing aging time. The Cu₆Sn₅ and (Ni,Cu)₃Sn₄ grains grew by merging adjacent grains. In the process of growth, the growing interfacial compounds filled the free space, and new columnar dendrite grain of (Ni,Cu)₃Sn₄ constantly generated during aging treatment. After 15 days aging, the Ni-W-P barrier layer was still remained, which indicated that the Ni-W-P layer can be a good barrier layer between the solder alloys and Cu substrate.

The microstructure and texture evolution of Fe-33Mn-3Si-3Al twinning induced plasticity (TWIP) steel were studied by the scanning electron microscope (SEM) and X-ray diffraction (XRD) at room temperature. After quasi-static tensile, the texture evolution of different strain was observed. It was shown that the Goss and Brass components increased within the strain range of less than 0.6. Whereas, the main components were decreased when the strain levels were greater than 0.6. This behavior was attributed to the low stacking fault energy (SFE) and was related to the strain energy of this high manganese steel. At high strain levels, the high strain energy may contribute to the Brass components transition to the A (rot-Brass) components.

Polyaniline (PANI)/Ce(NO₃)₃ composite with short fiber-like shape was synthesized successfully in a poly (2-arcylamido-2-methylpropane sulfonic acid) aqueous solution. A comparison of SEM images found that short fiber-like composites can be obtained by controlling the dosage of Ce(NO₃)₃. The length and diameter of short fiber-like PANI/Ce(NO₃)₃ composite was about 630 and 200 nm, respectively. A special conjugated structure had formed via Ce³⁺ ions and–NH–group in the quinonoid ring of PANI, which was characterized by means of Fourier transform infrared (FTIR) spectroscopy, Ultraviolet-visible (UV-Vis) spectroscopy and X-ray photoelectron spectroscopy (XPS). Short fiber-like PANI/Ce(NO₃)₃ composite exhibited a high conductivity, a large capacitance and an enhanced anticorrosion property. Linear four-probe method confirmed that the electrical conductivity of composites was improved with the presence of Ce³⁺ ions. The corrosion potential of PANI/Ce(NO₃)₃ composite increased to -79 mV at 10 wt% of Ce(NO₃)₃. Meanwhile, the minimum density of corrosion current (1.4 μA/cm²) was also achieved.

Polymer-based composite was investigated by embedding calcium copper titanate (CaCu₃Ti₄O₁₂; CCTO) fillers into polytetrafluoroethylene(PTFE) matrix. The dielectric performances of the composite were investigated within the frequency range from 100 Hz to 1 MHz. It is indicated that dielectric permittivity (ε) and dielectric loss (tanδ) increase gradually as the filler content increases. Dielectric permittivity for the composite with 50 vol% CCTO filler loading is 33.5, approximately 16 times higher than that of pure PTFE (ε = 2.1) at 100 Hz. As the frequency increases, the dielectric loss decreases rapidly and reaches stability, and then remains low when the frequency rises to 1 MHz. The values for dielectric permittivity and dielectric loss in the microwave frequency (8-13 GHz) are lower than that in low frequency of 10 kHz for the composites because of different polarization modes. Several theoretical models were implemented to compare the experimental results with the theoretical calculations and the modified Lichtenecker equation was found to fit the best.

A series of poly (ethylene oxide) (PEO) membranes with star-like structures for CO₂/ H₂ separation were prepared by the photo-polymerization method. The structure of PEO membrane was characterized by Fourier transform infrared spectroscopy (FTIR). The thermal property and inter-segmental distance of polymer chain were investigated by differential scanning calorimetry and wide-angle X-ray diffraction, respectively. The density was determined by hydrostatic weighing method. The gas permeability, solubility and diffusivity of CO₂ and H₂ were investigated in the star-like PEO membranes. The relationship between gas permeation performances and physical properties was also discussed. The membrane exhibits outstanding CO₂ permeability (about 9.7×10^-11 cm³ (STP) cm/cm²/s/Pa) and CO₂/H₂ selectivity (about 11) compared with other membranes.

To elucidate the mechanism of brominated natural rubber (BNR), eight BNR samples with different bromine content were prepared from latex in different bromination time, and the microstructures were characterized by Fourier transform infrared spectroscopy (FTIR) and ¹H-NMR spectroscopy, respectively. The hardness of BNR increased and its nature transformed from elastomer to resin with the increase of bromine content. Unlike chlorinated natural rubber (CNR), FTIR showed that there were no carbonyl groups on the molecular chains of BNR. ¹H-NMR spectroscopy revealed that the reaction activity of bromine and the secondary hydrogen atom of BNR were much higher than those of the primary one. The brominated substitution took place in the hydrogen atom of CH₃ and CH₂ groups firstly, then in the late period of bromination the bond of C=C was transferred to the saturated bond of C-C due to the Markovnikov addition of hydrogen bromide. Based on these findings, the mechanism of BNR from latex could be deduced as a free radical reaction and the detailed bromination process was presented.

Composite nanofiber membranes based on biodegradable poly(lactic acid) (PLA) and cellulose nanofibrils (CNF) were produced via electrospinning. The influence of CNF content on the morphology, thermal properties, and mechanical properties of PLA/CNF composite nanofiber membranes were characterized by field scanning electron microscopy (FE-SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA), respectively. The results show that the PLA/CNF composite nanofibers with smooth, free-bead surface can be successfully fabricated with various CNF contents. The introduction of CNF is an effective approach to improve the crystalline ability, thermal stability and mechanical properties for PLA/CNF composite fibers. The Young’s moduli and tensile strength of the PLA/CNF composite nanofiber reach 106.6 MPa and 2.7 MPa when the CNF content is 3%, respectively, which are one times higher and 1.5 times than those of pure PLA nanofiber. Additionally, the water contact angle of PLA/CNF composite nanofiber membranes decreases with the increase of the CNF loading, resulting in the enhancement of their hydrophilicity.

A simple route to synthesize the polyaniline (PANI) nanofibers with diameter about 150 nm was reported. In this strategy, the PANI nanofibers were fabricated by electrochemical deposition by using two-electrode configuration in 0.01 M aniline and 0.01 M H₂SO₄ electrolytes. The as-prepared materials were characterized by scanning electron microscopy (SEM), infrared spectroscopy (FTIR), Raman spectroscopy and thermogravimetric analysis (TGA). The electrochemical properties of the PANI nanofibers electrode as supercapacitor materials were investigated. The PANI nanofibers electrode showed high capacitance of 485 F·g^-1 at 0.1 A·g^-1, and the decrease in the specific capacitance is about 3.5% in 1 000 cycles. The results indicate that the PANI nanofibers electrode shows high stability and retains its electrochemical capacitance property over 1 000 cycles, suggesting PANI nanofibers have promising applications in high-performance supercapacitors.

A series of solar radiation tests for the polytetrafluoroethylene(PTFE) bulk and film samples were carried out using Q-SUN XE-3-HSC type Solar Radiation Simulator, with the test parameters as follows: radiation intensity is 1 120 W/m², temperature is 55 °C and humidity is 70% RH. Surface morphology, composition and microstructure of the PTFE samples before and after radiation tests were characterized contrastively. Effect of solar radiation on the tribology and wetting properties of PTFE were also studied by tribometer and contact angle tester, respectively. The results show that, for radiated PTFE, surface roughness, the relative content of C element, the friction coefficients and the contact angle with water increased in varying degrees. In conclusion, the obvious change in PTFE samples can be mainly attributed to break of (CFx)-C bonds after bombardment of high energy UV photons, which causes the loss of F-rich groups, oxidation, crosslinking and restructuring of active unsaturated groups.

The bovine hydroxyapatite (BHA) was applied to prepare biological tissue engineering scaffolds by the method of extrusion freeforming. To achieve this goal, BHA were added to sodium alginate (SA) solution to form a slurry system in appropriate proportion. The resulting mixtures were fabricated to be a kind of controllable and porous scaffolds followed with cross-linking in 5% calcium chloride (CaCl₂) solution for 24 h. After that, the scaffolds were sintered in air at 1 000, 1 100, 1 200 and 1 300 °C for 5 h. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) studies were performed on the scaffolds to analyze its microstructure and constituent. To explore the effect of sintering temperature on scaffolds, the compressive strength, volume shrinkage and water absorptivity of BHA-SA composite scaffolds after sintering were investigated. The research tests indicated the feasibility of applying BHA powder to 3D printing. Besides, the scaffolds sintered in a respectively lower temperature possess much more pores and performed higher water absorptivity, which means better cellular affinity. And scaffolds sintered between 1 100 and 1 200 °C presents higher compressive strength.

Polyethyleneimine (PEI) functionalized Fe₃O₄ MNPs were synthesized by a modified hypothermal oxidative hydrolysis method. The magnetic nanoparticles showed positively charged surface, strong magnetic responsivity and uniform particle size distribution at 56.1±0.6 nm. Aggregation of these magnetic nanoparticles were observed on the surface of different type of bacteria. Magnetic capturing of bacteria were facilitated by these magnetic nanoparticles. The capturing efficiency could reach 90% after two rounds of interactions of 5 minutes. The mechanism and process of interactions between bacteria and polyethyleneimine functionalized Fe₃O₄ magnetic nanoparticles were explored and discussed. The present study not only provides insight into interactions between Fe₃O₄@PEI MNPs and bacterial cells, but also opens a new avenue for designing and applying Fe₃O₄@PEI MNPs as biosensors in microbiology, medicine, and environmental science.

Toxicity of MgO and ZnO nanoparticles at concentrations of 250, 500 or 1 000 mg/L for Citrus maxima seedlings was investigated to evaluate the potentiality of their use as nano-fertilizers. Uptake and translocation of metal oxide nanoparticles and lipid peroxidation were measured and compared with those of plants exposed to the highest equivalent concentrations of Mg²⁺ and Zn²⁺. MgO nanoparticles were translocated from roots to shoots, while translocation of ZnO nanoparticles was low. Exposure to Mg²⁺ and MgO at all concentrations entailed severe toxicity and strong oxidative stress. ZnO nanoparticles showed only mild toxicity, while Zn²⁺ caused leaf vein chlorosis and strong oxidative stress to plant shoots. In conclusion, the toxicity of MgO nanoparticles to the plant resulted from the dissolved Mg²⁺ concentration, while that of ZnO nanoparticles was not correlated with the dissolved Zn²⁺ concentration. Our findings are significant for development and application of MgO and ZnO nanoparticles as nano-fertilizers in agriculture.

Transparent hydroxyapatite (HAp) ceramics with the grain size ranging 86–1 300 nm were successfully synthesized by spark plasma sintering (SPS) at 925–1 200°C. All the sample achieved final density higher than 99.7%. The phase stability was identified by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The experimental results indicate that there is no decomposition or dehydroxylation during the SPS processes. The influences of microstructure refinement on the hardness were investigated using Hall- Petch (H-P) relationship, and the hardness of transparent HAp ceramic increases with the decrease of grain size. It is demonstrated that the grain boundaries and defects play important roles on the hardness.