Low-cost porous calcined dolomite microspheres were prepared by simple spray drying and subsequent calcination. Effects of calcination temperature on phase evolution and adsorption properties of MB were investigated systematically. Results showed that microspheres treated at 400 °C kept mainly calcium carbonate (CaMg (CO₃)) phase with some small pores, showing better removal efficiency for MB. With the dosage of 20 g/L under the starting concentration of 100 mg/L, the removal efficiency of the microspheres reached 95.6%. The adsorption kinetics data followed the pseudo-second-order kinetic model, and the isotherm data fit the Langmuir isotherm model. The low-cost microsphere could be applied as a promising absorbent for dyes in wastewater filtration and adsorption treatment.

Chemically functionalized carbon nanotubes were combined with PVC to enhance both toughness and strength by simply mixing long alkyl chain modified multi-wall carbon nanotubes (abbreviated as MWNTs) or Ester-functionalized soluble MWNTs (abbreviated as eMWNTs) with PVC in Tetrahydrofuran (THF)/Cyclohexanone (CH) solution to obtain good dispersity solution. The MWNTs modified with 1-Bromohexadecane can effectively increase the intermolecular force with PVC by hydrogen bond. The obtained nanocomposite has a regular shape with homogeneously dispersed particles. PVC/2 wt% eMWNTs has been proved to possess excellent thermal stability. The intermolecular force between eMWNTs and PVC endows the as-fabricated nanocomposite with enhanced toughness and strength, indicating that our method is promising for wide use in PVC/eMWNTs nanocomposition.

Novel visible light magnetically separable graphene-based BiOBr composite photocatalysts were prepared for the first time. The structures, morphologies and optical properties were characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction and ultraviolet-visible spectroscopy, respectively. The photocatalytic activity of the resulting samples was evaluated by degradation of tetracycline under visible light irradiation. An appropriate amount of introduced graphene can significantly enhance the photocatalytic activities. The enhanced activities were mainly attributed to the enhanced light absorption and the interfacial transfer of electrons. The corresponding photocatalytic mechanism was proposed based on the results.

Polytetrafluoroethylene (PTFE) is a commonly used seal material for oil-free engine that is well known for its excellent tribological properties. In this work, the nano-ZrO₂ particles were used as the friction modifiers to improve the friction and wear performance of PTFE-PPS composites. The friction and wear characteristics of PTFE/PPS-nano-ZrO₂ composites were investigated by a block-on-ring tester under dry friction sliding condition. The worn surfaces, counterpart transfer films and wear debris were studied by scanning electron microscopy and X-ray photoelectron spectroscopy. It was found that the increase of nano-ZrO₂ content could effectively reduce the coefficient of friction and enhance the anti-wear ability of PTFE-PPS composites. Especially, the best tribological properties of the composites were obtained when the particle content of nano-ZrO₂ was 10 vol%, the anti-wear performance of composite is 195 times better than that of the unfilled PTFE-PPS composite. Under different conditions, the coefficient of friction of PTFE/PPS-nano-ZrO₂ composites was more affected by the applied load while the wear rate was more affected by the sliding velocity.

Al-matrix composites reinforced with 56.5 vol% SiC were prepared by powder metallurgy with different amounts of additives and surface modifications of SiC_p. The crystalline phase, morphology, elements on the surface of SiC_p and the interface between SiC_p and Al were characterized by XRD, SEM, EDS and EPMA. The results show that it is favorable for the reaction between TiO₂-C on the surface of SiC_p and Al at the SiC_p-Al interface at 1 050 °C. Besides, the process of Na₃AlF₆ melting, dissolving and then contacting with Al₂O₃ formed the NaF-AlF₃-Al₂O₃ system, which generated OAlF²⁻, promoting the dessolution of Al₂O₃ film on the surface of Al powder. Na₃AlF₆ meets the needs of chemical reaction in TiO₂-C-Al system at the SiC_p-Al interface in the way of offering more molten Al. After 0.75 wt% Na₃AlF₆ was added into raw materials, the whole TiO₂-C film and most SiO₂ film were destroyed and the interfacial bonding between SiC_p and Al was keeping good, in which no obvious void and crack were observed. Meanwhile, no brittle Al₄C₃ phase formed in the system. At this time, the flexure strength and density of samples presented optimal values, reaching up to 106.5 MPa and 90.77% respectively.

The parameters for the electro-deposition of Cu were optimized in order to increase the compressive properties of close cell aluminum. Different values of deposition voltages and times were considered to vary the amount of deposited Cu. The surface morphology of the coating was observed by SEM and the compressive properties were evaluated by MTS. The results show that the coating is more homogeneous and compact with increasing voltage in a certain range, and beyond which, the coating quality decreases apparently. The reason is dedicated to the discharge rate of Cu²⁺ and nucleus formed in unit time. The compression results show three experienced stages: elastic deformation stage, collapse deformation stage and densification stage. After the electro-deposition of Cu, the elasticity modulus is increased obviously and the platform stress is also increased. Under the same strain, the stress of the aluminum foam with coating is reinforced comparing with the aluminum foam without coating. Furthermore, the platform area is widened apparently. In addition, Cu-SiC nanocomposite coatings are electrodeposited in alumium foams for further improving the mechanical characterization.

The effect of spherical particle size on the surface morphology, electrochemical property and processability of lithium iron phosphate was systematically studied. Spherical lithium iron phosphate with different particle size distributions controlled with ball time of precursor slurry was prepared by spray drying method. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), charge and discharge measurements and EIS. The electrochemical performances of the sample materials were measured by coin cells and 14500 batteries. XRD shows that the spherical lithium iron phosphate with different particle sizes all have good crystal structure due to the perfect mixing of the raw materials and rapid drying. The lithium iron phosphate microsphere with different particle sizes self-assembled with submicron primary particles has a core-shell structure. The longer ball time the precursors are, the smaller the active material particles are prepared. The electrode material with 6 h ball time of precursor slurry has the best physical properties and the processability. The composite has a uniform particle size and higher tap density of 1.46 g/cm³, which delivers a discharge capacity of 167.6 mAh/g at a discharge rate of 0.5 C. The results were confirmed by the 14 500 mA·h cylindrical batteries, which delivers a discharge capacity of 579 mAh at 0.5 C. And low-temperature performance with capacity of 458.5 mA h at −20 °C under a discharge rate of 0.5 C is the 79.2% of the same discharge rate at 25 °C. Otherwise, the 14500 batteries also exhibit excellent cycling performance and the capacity maintains 93% after 2 000 cycles.

Fluoride nanoparticles with multiform crystal structures and morphologies were successfully synthesized by a facile, effective, and environmentally friendly coprecipitation method. Transmission electron microscopy (TEM) was used to characterize the nanoparticles. The nanoparticles were modified by PEI, CTAB, PAA and Ci, respectively. It was feasible for function by -COOH and -NH₂ groups, due to the surface modification. Moreover, different surface modifications of the nanoparticles were examined. The possible formation mechanisms for fluoride nanoparticles with surface modification were presented in detail. More importantly, it is expected to be widely applied to biomedicine.

Zn₂SnO₄/few-layer boron nitride nanosheets (FBNNS) hybrids were synthesized via a one-step hydrothermal method. The structures, morphology, optical properties, electron transformation and separation of the as-prepared products were characterized by X-ray diffraction, transmission electrical microscopy, UV-vis diffuse reflectance spectroscopy and electrochemical impedance spectroscopy, respectively. Rhodamine B was used to evaluate the photocatalytic activities of the as-prepared samples under visible light illumination. The photocatalytic mechanism was also explored. Experimental results showed that the degradation efficiency of rhodamine B was firstly increased and then decreased with increasing the usage amount of FBNNS. When it was 9 wt% based on the weight of Zn₂SnO₄, the degradation efficiency of the as-prepared Zn₂SnO₄/FBNNS-9 wt% composites reached to the maximum of 97.5% in 180 min, which was higher than 39.2 % of pure Zn₂SnO₄. Moreover, the holes played mainly active roles in photocatalytic reaction process. In addition, the as-prepared hybrids could enhance the separation efficiency of photoexcited carriers compared to pure Zn₂SnO₄.

Ag/La_0.5Mg_0.5MnO₃/p⁺-Si resistance switching device for nonvolatile memory application was fabricated by sol-gel method. The thickness effects of La_0.5Mg_0.5MnO₃ (LMMO) films on current-voltage (I–V) characteristics, resistance switching behaviour and endurance characteristics of Ag/LMMO/p⁺-Si device were investigated. The same crystallisation and phase structure were confirmed in the LMMO films with increased film thickness. The Ag/LMMO/p⁺-Si device exhibits the typical bipolar resistive switching behaviour. As the LMMO thickness and the stable repetition switching cycle numbers increase, V _Set, and V _Reset of the device will increase, but the R _HRS/R _LRS will decrease. The Ag/LMMO/p⁺-Si device with 165 nm thick LMMO films exhibit the best performance, in which the R _HRS/R _LRS exceeds 10⁴ for 1 000 switching cycles, and its degradation is invisible for more than 10⁶ s.

The vanadium oxide/reduced graphene oxide (V₂O₅/rGO) composite catalyst which determined the selective catalytic reduction activity (SCR) of NO with NH₃ was prepared by a simple solvothermal method. The physicochemical properties of the catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman, X-ray energy spectrometer (XPS) and N₂ sorption isotherm measurement (BET). Results of NH₃-SCR showed that the NO conversion of V₂O₅/rGO catalyst could reach 54.3% at 100 °C. And the removal of NO increased to 74.6% when the temperature was up to 220 °C. By characterizing the microstructure and morphology of the V₂O₅/rGO catalysts prepared by in-situ growth and mechanical mixing methods, it was further shown that V₂O₅ nanoparticles were highly dispersed and in situ growth on the rGO surface. Based on X-ray energy spectrometer, V₂O₅/rGO catalyst had good low temperature denitrification performance due to the chemical adsorption oxygen and low-valent vanadium oxide contained in V₂O₅/rGO catalyst, which was beneficial to the redox reaction between V₂O₅ and graphene.

Al₂O₃ hollow microspheres without noticeable aggregation have been prepared via a facile templating route with urea-mediated precipitation. The precipitation process is different from the surface-adsorption method which is confined to the adsorption capacity of the template surface. TEM and SEM images indicate that most of these Al₂O₃ hollow microspheres with shell thickness of tens of nanometers and diameters in a narrow range of 100–200 nm consist of a shell of closely packed nanoparticles. The optimal amount of H₂O and EtOH are 40 and 120 mL, respectively. The specific surface area, average pore size and pore volume of the Al₂O₃ hollow microspheres (calcinated at 600 °C) are 328.52 m²/g, 17.496 nm and 1.985 cm³/g, respectively. As the calcination temperature increases from 600 to 1 100 °C, the phase composition changes from γ-Al₂O₃ to θ-Al₂O₃ and α-Al₂O₃, and the surface morphology appears to change from a relatively rough surface formed by nanoparticles to a smooth surface formed by lamellar, which lead to the closure of pore channels and the reduction of specific surface.

The isothermal absorption properties and kinetic model of Cr (VI) and Cr (III) onto ettringite were investigated using the batch adsorption method. IR analysis was used to study the difference and mechanism of the adsorption of chromium ions with different valence states. The results show that the adsorption of Cr(III) onto ettringite at 20 °C agrees with Langmuir’s isothermal model. The ion binding stability was significantly greater than that of Cr (VI). While the adsorption of Cr(VI) onto ettringite agrees with Freundlich’s isothermal model, the D-R model fits the adsorption isotherms of two types of valence Cr (R ²> O.994). It can be concluded that the adsorption of Cr (III) onto ettringite is mainly by chemical adsorption and that the adsorption of Cr (VI) onto ettringite is mainly by physical adsorption. Dynamic model fitting and model parameter analyses show that the adsorption of Cr (III) onto ettringite agrees with the pseudo second order kinetics model given by Lagergren. The formation of chemical bonds is the main factor causing the fast adsorption. Cr (VI) adsorption is mainly dominated by liquid film diffusion, and the adsorption rate is much slower than that of Cr (III) adsorption.

Hydration heat behavior and kinetics of blended cement containing up to 20% MSWI fly ash were investigated based on its hydration heat evolution rate measured by isothermal calorimeter. Kinetics parameters, N and K, and hydration degree, Ca(OH)₂ content, were also calculated and analyzed. According to the experimental results, the induction period was elongated, the second heat evolution peak was in advance, and the third hydration heat peak could be detected due to MSWI fly ash pozzolanic reaction. The hydration reaction rate was controlled by nucleation kinetics in the acceleration period and then by diffusion in the decay period, but in the deceleration period, the hydration experienced a dual controlling reaction of autocatalytic chemical reaction and diffusion. The hydration rate of blended cement was faster. Ca(OH)₂ content increased before 14 days.

The influences of nano silica (NS) on the hydration and microstructure development of steam cured cement high volume fly ash (40 wt%, CHVFA) system were investigated. The compressive strength of mortars was tested with different NS dosage from 0 to 4%. Results show that the compressive strength is dramatically improved with the increase of NS content up to 3%, and decreases with further increase of NS content (e g, at 4%). Then X-ray diffraction (XRD), differential scanning calorimetry-thermogravimetry (DSCTG), scanning electron microscope (SEM), energy disperse spectroscopy (EDS), mercury intrusion porosimeter (MIP) and nuclear magnetic resonance (NMR) were used to analyze the mechanism. The results reveal that the addition of NS accelerates the hydration of cement and fly ash, decreases the porosity and the content of calcium hydroxide (CH) and increases the polymerization degree of C-S-H thus enhancing the compressive strength of mortars. The interfacial transition zone (ITZ) of CHVFA mortars is also significantly improved by the addition of NS, embodying in the decrease of Ca/Si ratio and CH enrichment of ITZ.

The influence of replacement level of calcined coal-series kaolin (CCK) on hydration of ordinary Portland cement (OPC) was studied by X-ray diffraction(XRD)/Rietveld method. X-ray diffraction/Rietveld method was used to quantify the crystalline phase composition of the hydrated samples. Additionally, the morphology of hydrated samples was observed by scanning electron microscopy (SEM). The results showed that, calcium hydroxide (CH), ettringite (AFt) and amorphous phase content in hydrated samples decreased as the replacement level of CCK increased, while AFm and strätlingite increased, which was caused by the combination of dilute, physical and pozzolanic effects. The hydration of anhydrous cement phases was accelerated by physical effect but hindered by the retardation effect of CCK. The role of each effects was discussed in detail to analyze the mechanism of OPC hydration with CCK addition. The SEM images showed that the shortening of AFt at 1 day and the denser texture at 28 days was observed with CCK addition, which was caused by the physical and pozzolanic effects, respectively.

Concrete creep under both static and cyclic loading conditions was investigated. Four groups of high-strength high-performance concrete (HSHPC) prism specimens were fabricated, and three of these specimens were loaded periodically by the MTS Landmark Fatigue Testing Machine System. Creep characteristics and creep coefficients of HSHPC under static loading and cyclic loading, respectively, were obtained and compared. The experimental results show that the creep strains under cyclic loading with a mean stress of 0.4 f _cp and an amplitude of 0.2 f _cp increase significantly compared with the creep strains under static loading, and the maximum value was 1.2–2.3 times at early stages. In addition, the creep coefficient increases nonlinearly with the number of cyclic loading repetitions. The influence coefficient for cyclic loading γ _cyc=1.088×(N/N ₀)^0.078 was introduced based on the previous HSHPC creep model, and then the modified creep model under cyclic loading was established. Finally, the residual method, the CEB coefficient of variation method and the B3 coefficient of variation method were applied to evaluate the modified creep model. The statistical results demonstrate that the modified creep model agrees well with the experimental measurements. Hence, it has important theoretical and practical values for accurately predicting the deflection of concrete bridges under cyclic traffic loading.

In order to inhibit and remove the thin ice and extend the lifetime of the damaged bridge, the self-healing mechanism and hydrophobic performance of asphalt modified by siloxane and polyurethane (ASP) were studied by dynamic shear rheology (DSR), fluorescence microscope (FM), atomic force microscope (AFM), the fracture-healing-re-fracture test and molecular simulations. The experimental results indicated that the self-healing capability of ASP increased with increasing heating time and temperature. Furthermore, the addition of siloxane could improve the reaction energy barrier and complex modulus, and it is believed that the self-healing is a viscosity driven process, consisting of two parts namely crack closure and properties recovery. Contact angle of ASP increased with the increasing siloxane content and it deduced that the siloxane could improve the hydrophobic performance of ASP and the ASP molecule model could simulate well the self-healing mechanism and hydrophobic performance of ASP.

The thermodynamic stability of sulfate ions on synthesized calcium aluminosilicate hydrate (C-A-S-H) microstructure with different Ca/Si ratios and Al/Si ratios was investigated by XRD, SEM-EDS, ²⁹Si and ²⁷Al nuclear magnetic resonance (NMR) and thermodynamic modeling. The results indicate that sulfate attack leads to both decalcification and dealumination for C-A-S-H gels, and the amount of corrosion products (gypsum and ettringite) decreased gradually with decreasing Ca/Si ratios of C-A-S-H. Sulfate ions can also promote the polymerization degree of C-A-S-H gels, improving its resistance to sulfate attack. Moreover, the 4-coordination aluminum (Al[4]) in C-A-S-H, 5-coordination aluminum (Al[5]), 6-ccordination aluminum (Al[6]) in TAH (third aluminum hydrate) and Al[6] in monosulfate or C-A-H (calcium aluminate hydrate) can be transformed into Al[6] in ettringite by sulfate attack. Furthermore, through thermodynamic calculation, the decrease of Ca/Si ratios and increase of Al/Si ratios can improve the thermodynamic stability of C-A-S-H gels under sulfate attack, which agrees well with the experiment results.

The interfacial transition zone (ITZ) between the aggregates and the bulk paste is the weakest zone of ordinary concrete, which largely determines its mechanical and transporting properties. However, a complete understanding and a quantitative modeling of ITZ are still lacking. Consequently, an integrated modeling and experimental study were conducted. First, the theoretical calculation model of the ITZ volume fraction about the rotary ellipsoidal aggregate particles was established based on the nearest surface function formula. Its calculation programs were written based on Visual Basic 6.0 language and achieved visualization and functionalization. Then, the influencing factors of ITZ volume fraction of the ellipsoidal aggregate particles and the overlapping degree between the ITZ were systematically analyzed. Finally, the calculation models of ITZ volume fraction on actual ellipsoidal aggregate were given, based on cobblestones or pebbles particles with naturally ellipsoidal shape. The results indicate that the calculation model proposed is highly reliable.

A modified Bridgman directional solidification technique was used to prepare Fe-Al-Ta eutectic in situ composites at different growth rates ranging from 6 to 80 µm/s. The directionally solidified Fe-Al-Ta eutectic composites are composed of two phases: Fe(Al,Ta) matrix phase, and Fe₂Ta(Al) Laves phase. Solidification microstructure is affected by solidification rate. Microstructure of the Fe-Al-Ta eutectic alloy grown at 6.0 µm/s is broken-lamellar eutectic. Eutectic colonies are formed with the increase of the solidification rate. Microstructures are mainly composed of the lamellar or fibrous eutectic at the center of the colony and coarse lamellar eutectic zone at the boundary. Meanwhile, the inter-lamellar spacing (or the inter-rod spacing) is decreased. The spacing adjustments are also observed in Fe-Al-Ta eutectic alloy. The solid/liquid interface evolves from planar interface to shallow cellular interface, then to deep cellular, and finally to shallow cellular planar with the increase of the solidification rate.

In order to explore the application of magnetron co-sputtering in fabricating the amorphous alloy, Zr-contained amorphous films were prepared by this technique and investigated by scanning electron microscope, energy disperse spectroscopy and X-ray diffraction. The results show that the co-sputtered films are in fully amorphous state or with amorphous-nanocrystalline structure. The XRD patterns of the Zr-Cu and Zr-Ni amorphous films exhibit a double-peak phenomenon. There is a shift of diffusive peak with changing the sputtering current which is possibly attributed to the change of Zr-Ni and Zr-Cu intermetallic like short range orders. In addition, Zr-Cu-Ni ternary co-sputtered films have a sharper peak at high angle. The sputtering yield of element during co-sputtering ranks as Cu>Ni>Zr, which can be ascribed to the contribution of melting and boiling temperature, atomic size and electrical conductivity of elements.

The effects of different Bi contents on the properties of Sn solders were studied. The interfacial reaction and growth behavior of intermetallic compounds (IMCs) layer (η-Cu₆Sn₅ + ε-Cu₃Sn) for various soldering time and the influence of Bi addition on the thermal behavior of Sn-xBi solder alloys were investigated. The Cu₆Sn₅ IMC could be observed as long as the molten solder contacted with the Cu substrate. However, with the longer welding time such as 60 and 300 s, the Cu₃Sn IMC was formed at the interface between Cu₆Sn₅ and Cu substrate. With the increase of soldering time, the thickness of total IMCs increased, meanwhile, the grain size of Cu₆Sn₅ also increased. An appropriate amount of Bi element was beneficial for the growth of total IMCs, but excessive Bi (⩾ 5 wt%) inhibited the growth of Cu₆Sn₅ and Cu₃Sn IMC in Sn-xBi/Cu microelectronic interconnects. Furthermore, with the Bi contents increasing (Sn-10Bi solder in this present investigation), some Bi particles accumulated at the interface between Cu₆Sn₅ layer and the solder.

Low melting point alloy is a potential high-temperature heat transfer medium because of the high thermal conductivity, low solidus temperature and wide range of use temperature. Consequently, we investigated the possibility of using Sn–Bi–Zn–Ga alloys as heat storage and heat transfer material. Moreover, we investigated the microstructure and phase compositions by electron probe micro-analysis (EPMA) and X-ray diffusion (XRD). Results show that the new structures and phases are formed in the alloy matrix with Ga additions, which lead to the improvement of the thermal properties. An extensive thermophysical characterization of the Sn–Bi–Zn–Ga alloys has been performed by differential scanning calorimeter (DSC) analysis. The addition of Ga lowers the peak temperature and increases the heat capacity of the alloys. The thermal expansion of the test alloys increases with increasing temperature and the densities decreases with Ga additions. As the density, specific heat capacity and thermal diffusivity change with temperature and physical state, the thermal conductivity of the alloys first decreases and then increases. These results demonstrate the feasibility of using Sn–Bi–Zn–Ga alloys as the high-temperature heat transfer fluid.

A 40Cr steel was formed into a chain-wheel using a warm extrusion technology. The surface roughness and micro-structure, micro-hardness and phases of the extruded samples at different temperatures were analyzed using a three-dimensional optical microscope (OM), micro-hardness tester, and X-ray diffraction (XRD), respectively. The morphologies, chemical element distributions and phases of worn tracks at the extrusion temperatures of 550, 650 and 750 °C were analyzed using a scanning electron microscopy (SEM), energy disperse spectroscopy (EDS), and XRD, respectively. The friction-wear behaviors of extruded samples under oil-lubrication condition were observed using a wear test. And the effects of extrusion temperatures on the wear mechanism were discussed. The results show that residual austenite and pearlite exist on the sample at the extrusion temperature of 550 °C with the corresponding grain size and surface micro-hardness of 32.7 nm and 370.33 HV, respectively. The average coefficient of friction (COF) of extruded sample at the temperature of 550 °C is 0.196 5, and the wear mechanism is fatigue and abrasive wear. While the acicular martensite exists on the extruded samples at the extrusion temperatures of 650 and 750 °C, the corresponding grain sizes are 30.0 and 29.1 nm, respectively. The average COF (coefficient of friction) of extruded sample at the temperatures of 650 and 750 °C are 0.187 4 and 0.163 6, respectively, and the wear mechanism is abrasive wear. As a result, the friction performance of extruded sample at the temperatures of 650 and 750 °C is better than that at the temperature of 550 °C.

The industrial trials of two cooling modes, i e, water cooling in forepart + air cooling in later part (WAC) and air cooling in forepart + water cooling in later part (AWC), were carried out for a Ti-Nb microalloyed steel. The average cooling rates and coiling temperature were the same for two modes. The continuous cooling transformation (CCT) curve of the tested steel was drawn. The effects of the cooling mode on the microstructure, precipitates, and properties of the steels were investigated. Results show that the strength of the steel in the WAC mode is significantly larger than that in the AWC mode, mainly because the smaller the grain size, the more and finer the grain precipitates. Therefore, when the average cooling rate is constant, the fast cooling in the forepart is an effective method to increase the strength of steels. However, the increase in the strength is accompanied by the decrease in toughness, so that the toughness of the steel should be considered when changing the cooling mode.

The tribological properties of Nickel-based composites containing Ti₃SiC₂ and Ag₂W₂O₇ fabricated by spark plasma sintering against Si₃N₄ balls were investigated using a ball-on-disk tribometer from room temperature to 600 °C. The tribolayers formed on the friction surface and their effects on the tribological properties of composites at different temperatures were discussed based on the worn surface characterization. The results show that Ag₂W₂O₇ is decomposed into metallic silver and CrWO₄ during the high-temperature fabrication process. The composite with the addition of 20 wt% Ti₃SiC₂ and 5 wt% Ag₂W₂O₇ exhibits a friction coefficient of 0.33–0.49 and a wear rate of 7.07×10⁻⁵–9.89×10⁻⁵ mm³/(Nm) over a wide temperature range from room temperature to 600 °C. The excellent tribological properties at a wide temperature range are attributed to the formation of a glaze layer at low temperature and a tribooxide layer at high temperature, which can provide a low shearing strength for the synergistic effects of Ag and tribooxides.

The dynamic tensile behaviors of a newly developed Ti-6Al-2Sn-2Zr-3Mo-1Cr-2Nb-Si alloy (referred as TC21 in China) over a wide range of strain rates from quasi-static to dynamic regimes (0.001–1 200 s⁻¹) at different temperatures were experimentally investigated. A split Hopkinson tension bar apparatus and a static material testing system were utilized to study the stress-strain responses under uniaxial tension loading condition. The experimental results indicate that the tensile behavior of TC21 titanium alloy is dependent on the strain rate and temperature. The values of initial yield stress increase with increasing strain rate and decreasing temperature. The effects of strain rate and temperature on the initial yield behavior are estimated by introducing two sensitivity parameters. The phenomenological-based constitutive model, Johnson-Cook model, is suitably modified to describe the rate-temperature dependent constitutive behavior of TC21 titanium alloy. It is observed that the modified model is in good agreement with the experimental data subjected to the investigated range of strain rates and temperatures.

The functional groups on graphene sheets surface affect their dispersion and interfacial adhesion in polymer matrix. We compared the mechanical property of polymethymethacrylate (PMMA) microcellular foams reinforced with graphene oxide (GO) and reduced graphene oxide (RGO) to investigate this influence of functional groups. RGO sheets were fabricated by solvent thermal reduction in DMF medium. UV-Vis, FT-IR and XPS analyses indicate the difference of oxygen-containing groups on GO and RGO sheets surface. The observation of SEM illustrates that the addition of a smaller number of GO or RGO sheets causes a fine cellular structure of PMMA foams with a higher cell density(about 10¹¹ cells/cm³) and smaller cell sizes (about 1–2 µm) owing to their remarkable heterogeneous nucleation effect. Compared to GO reinforced foams, the RGO/PMMA foams own lower cell density and bigger cell size in their microstructure, and their compressive strength is lower even when the reinforcement contents are the same and the foam bulk density is higher. These results indicate that the oxygen-containing groups on GO sheets’ surface are beneficial to adhere CO₂ to realize a larger nucleation rate, and their strong interaction with PMMA matrix improves the mechanical property of PMMA foams.

The damage mechanism and energy dissipation of the Polyethylene (PE) laminates in impacting was investigated. It was found that the dissipated energy of the impacting sphere bullet by the 1-mm-thick PE plate firstly increased with the impacting velocity increasing from 50 to about 300 m/s, and then decreased with the impacting velocity increasing up to 600 m/s. According to the measured deformation and damage degree, a numerical simulation of the dissipated energy was made and obvious offset was found with the experimental results. The quasi-static properties of the PE fibers, decreasing with increase in tensile velocity, may be the main reason for the offset.

A 1-octadecanol (OD)/1,3:2,4-di-(3,4-dimethyl) benzylidene sorbitol (DMDBS)/expander graphite (EG) composite was prepared as a form-stable phase change material (PCM) by vacuum melting method. The results of field emission-scanning electron microscopy (FE-SEM) showed that 1-octadecanol was restricted in the three-dimensional network formed by DMDBS and the honeycomb network formed by EG. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) results showed that no chemical reaction occurred among the components of composite PCM in the preparation process. The gel-to-sol transition temperature of the composite PCMs containing DMDBS was much higher than the melting point of pure 1-octadecanol. The improvements in preventing leakage and thermal stability limits were mainly attributed to the synergistic effect of the three-dimensional network formed by DMDBS and the honeycomb network formed by EG. Differential scanning calorimeter (DSC) was used to determine the latent heat and phase change temperature of the composite PCMs. During melting and freezing process the latent heat values of the PCM with the composition of 91% OD/3% DMDBS/6% EG were 214.9 and 185.9 kJ·kg⁻¹, respectively. Its degree of supercooling was only 0.1 °C. Thermal constant analyzer results showed that its thermal conductivity (κ) changed up to roughly 10 times over that of OD/DMDBS matrix.

Colloidal semiconductor nanoparticles (quantum dots, QDs) have attracted a lot of interests in numerous biological and medical applications due to their potent fluorescent properties. However, the possible toxic effects of quantum dots remain an issue of debate. In this study, we aimed to evaluate the cytocompatibility of bovine serum albumin (BSA) conjugated zinc oxide QDs for C2C12 cells. In the experiment, ZnO QDs were synthesized by using BSA as the structure directing agent, and the morphology and crystal phase of ZnO QDs were determined by transmission electron microscopy, X-ray diffractograms and Fourier transform infrared spectrograph techniques. The inverted fluorescence microscope results showed that ZnO QDs were distributed inside the cells. The toxicity of ZnO QDs was assessed by MTT methods, which revealed that ZnO QDs were highly cytocompatible in the concentration less than 200 µM. However, when the concentration of QDs was higher than 1 000 µM ZnO QDs showed significantly toxicity, which was ascribed to generation of free zinc and formation of reactive oxygen species (ROS). Furthermore, the morphological observations exhibited that cells treated with ZnO QDs showed altered morphology, depolymerized cytoskeleton and irregular-shaped nuclei. This study provides helpful guidances on the future safe use and manipulation of QDs to make them suitable tools in nanomedicine.

One interpenetrating network hydrogel based on sodium alginate (SA) and polyvinyl alcohol (PVA) was synthesized by combining the raw materials of PVA and SA with the double physical crosslinking methods of freezing thawing and Ca²⁺ crosslinking. The PVA-SA composite hydrogel have been characterized by scanning electron microscopy for surface morphology, infrared spectroscopy for investigating the chemical interactions between PVA and SA, X-ray diffraction for studying the PVA-SA composite structure property and thermal gravimetric for understanding the PVA-SA composite thermal stability. The swelling behavior and the degradation rate of the PVA-SA composite hydrogel were studied in simulated gastrointestinal fluid. Using bovine serum albumin (BSA) and salicylic acid as the model drugs, the release behavior of the PVA-SA composite hydrogel on macromolecular protein drugs and small molecule drug were evaluated. The results showed that the water absorption and degradation ability of the PVA-SA composite hydrogel was much better compared to the pure SA hydrogel or pure PVA hydrogel. The hydrogel exhibited remarkable pH sensitivity and the network was stable in the simulated intestinal fluid for more than 24 h. With the advantages such as mild preparation conditions, simple method, less reagent and none severe reaction, the PVA-SA composite hydrogel is expected to be a new prosperous facile sustained drug delivery carrier.

A novel phosphoprotein separation material was developed, which is constructed by a magnetic mesoporous Fe₃O₄@TiO₂ (Fe₃O₄@mTiO₂) microsphere and a 5-aminoisophthalic acid (AIPA) monolayer that provides additional binding sites toward phosphate groups. The results of characteristic experiments demonstrated that Fe₃O₄@mTiO₂-AIPA had good dispersability, high magnetic susceptibility, and satisfactory grafting ratio of AIPA, ascribed to the large specific surface area of the inorganic substrate. Taking advantages of these features, Fe₃O₄@mTiO₂-AIPA was successfully utilized to separate α-casein (a typical phosphoprotein) and bovine serum albumin (BSA, a typical non-phosphoprotein) from their mixtures (molar ratio = 1:2). Through adjusting pH and polarity of solutions, the BSA and α-casein were respectively enriched in washing fraction and elution fraction. This result displays the good potential of Fe₃O₄@mTiO₂-AIPA for application in phosphoprotein enrichment.