The ion beam mixing prepared SiC films on stainless steel substrates were irradiated by hydrogen ion beam with an energy of 5 keV to a dose of 1×1018 ions/cm2. AES and XPS were used for the characterization of chemical bonding states of C and Si elements in SiC films as well as contamination oxygen before and after hydrogen ion irradiation in order to study the effect of hydrogen ion irradiation on SiC films and to understand oxygen behaviors in the SiC films prepared with ion beam mixing. The results show that contamination oxygen can react with silicon to form silicon oxides, and more oxygen entered into the films during hydrogen ion irradiation. In addition, oxygen also reacts with carbon related hydrogen to form species including carbon, hydrogen and oxygen.
X-ray diffraction (XRD) analysis on different polished surfaces normal to the hot pressing direction reveals that the phase compositions of the polished surfaces from the outside to the inside are pure TiC, Ti3AlC2+TiC, pure Ti3AlC2 and Ti2AlC+Ti3AlC2, no matter elemental powder or TiC is used as raw materials. It is found that ternary-layered carbide Ti2AlC samples synthesized at 1500°C by hot-pressing sintering are inhomogeneous and have a gradient structure. Electron probe X-ray micro-analysis (EPMA) indicates that the Al content along the hot pressing axis is parabolic, it is the highest in the center and the lowest at the both ends, while the Ti content is constant along the axis. The experimental result reveals that the evaporation of Al in samples in an open system during hot pressing sintering results in a gradient structure.
The tinting phenomena of iron oxide contained glasses were studied from aspects of the electronic configuration, the iron ions coordination fields and the ions structure in glass. Several iron ion tinting forms at different redox or COD (chemical oxygen demand) conditions and their influential factors were given necessary explanations. The results reveal that the Fe3+−O−Fe2+ structure is the real tinting reason of iron involved glasses, whereas the Si4+−O−Fe3+ and Si4+−O−Fe2+ formulations modify the glass colours. Under oxidizing melting condition, the amount of 4/6-coordinated Fe3+ increases and makes the glass colour yellowish. Conversely, reducing melting condition makes the 6-coordinated Fe2+ increased and gives much blue tint to the glass. The conventional tank furnace melting the very strong reducing condition, which is of high COD glass batch, is not suitable. The high ratio of ferrous/ferric in glass can be obtained with a new refining technology which contains no or little amount of refining agent.
Natural water absorbent konjac flour participates in synthesizing biodegraded and polyurethane foamed drape, which is used to release urea slowly. The experimental results indicate that the slowly-releasing velocity of urea nitrogen and the degrading velocity of the drape can be controlled by regulating the thicknesses of drapes, the amount of konjac flour and the water content. In addition, the biodegradability of the drape was investigated by burying the specimens in earth afterwards, and results show this drape can be degraded naturally.
Films were made from the wheat glutens treated with 5%, 10%, 15%, 20%, 25% and 30% (wt% of gluten) of sodium dodecyl sulfite (SDS) in order to improve the properties of the films. Glycerol was used as a plasticizer. An addition of SDS in wheat glutens prior to forming films significantly increased the elongation at break (E) (P<0.05) and reduced notably the water vapor permeability (WVP) (P<0.05). In contrast, a decrease in the tensile strength (TS) of the films from gluten containing-SDS was found. Moreover, a significant decrease in Po2 and Pco 2 of films from gluten treated with SDS was noticed. Although SDS-treated gluten film was slightly more yellow and darker than control one, it was not visually detrimental. It is indicated that the treatment with SDS prior to forming films greatly enhances the mechanical properties of wheat gluten films. The obivous improvement in water vapor permeability and extensibility of gluten films means that the use of SDS is a potential choice for improving properties of gluten filsm. The edible film was used to preserve tomatoes. The experimental results show that the shelf life of tomatoes coated with the edible film is extended, and the nutritional quality is kept well.
The biomimetic approach was applied to study the in vitro biomineralization of series of the chitosan films crosslinked by glutaraldehyde. The deposited calcium phosphate coatings were studied using scanning electron microscopy and energy dispersive X-ray analysis. Initially, the treatment in simulated body fluid (SBF) results in the formation of single layer of calcium phosphate particles over the film surface. As immersion time in SBF increases, further nucleation and growth produce a simulated calcium phosphate coating. The Cal P molar ratio of the calcium phosphate increases with the immersion time, showing a rapid formation of calcium-deficient phosphate material from the phase of octac 1 alcium phosphate. The different glutaraldehyde crosslinking degree influences the morphology and magnitude of the calcium phosphate coatings on the surface of the chitosan films.
A series of transparent casting polyurethane resins (TCPU) were synthesized from cycloaliphatic diisocyanate (IPDI or H12MDI), polyol, chain extender, crosslinking agents, catalyst and special aids (T), which were characterized by FTIR. The thermal stabilities of the obtained TCPU were examined by DSC and TGA, the glass transition temperature (Tg) was in the range of 95–110°C, the initial decomposition temperature (5% weight loss) was 250–265°C, and 10% weight loss at the temperature was in the range of 260–286°C in nitrogen atmosphere. The morphologies of the fractured surfaces of TCPU were revealed by a scanning electron microscope (SEM). The crystalline-amorphous characters of TCPU were studied by WAXD, the result shows that TCPU possesses amorphous glassy characters. The optical properties of TCPU were studied by a UV-7500 visible light absorbance measurement. All the samples exhibited excellent optical properties and possessed light transmittance in the range of 91%–93%.
A novel photosensitive prepolymer of trimethylolpropane triglycidylether triacrylate was synthesized by utilizing trimethylolpropane triglycidylether and acrylic acid as two starting materials, triphenyl phosphine as catalyst and p-hydroxyanisole as inhibitor. The optimum synthesis conditions were that the concentration of triphenyl phosphine was 0.85wt% of reactants, the concentration of p-hydroxyanisole was 0.3wt% of reactants, and the reaction temperature was at 90–110°C. Benzil dimethyl ketal of a UV-cured initiator was added to the synthesized trimethylolpropane triglycidylether triacrylate to prepare a kind of UV-cured coating. The mechanical properties of the UV-cured films were determined, giving 28. 43 MPa of tensile strength, 965. 59 MPa of Young’s modulus and 4.10% of elongation at tear.
Mesoporous silicon oxynitrides MCM-41 were synthesized successfully. The resulting materials not only have high nitrogen contents and good structural characteristics of MCM-41 (high surface area, narrow pore size distribution and good order), but also are amorphous. The composition and structure of the materials were investigated by CNH element analysis, XPS, Si MAS NMR, XRD, HRTEM and N2 sorption, respectively. Mesoporous silicon oxynitrides MCM-41 with a high nitrogen content are still non-crystal (amorphous).
In order to enhance the mucosal immunity of anti-caries DNA vaccine, chitosan-DNA microparticles for musocal vaccination were prepared by a coacervation method. The physicochemical structure of microparticles was investigated by a scanning electron microscope (SEM) and a cofocal laser scanning microscope (CLSM). For in-vitro studies, Hela cell was transfected by chitosan-DNA microparticles. The expression of proteins was measured by the immunohistochemical methods, and the cytotocity of chitosan in Hela cell line was determined by the MTT assay. The experimental results show that the microparticles are about 2–6 μm in size and spherical in shape. The encapsulation efficiency is 99%, and the DNA is almost captured in the micropraticles. Plasmid loaded into chitosan microparticles is distributed throughout these particles. The number of positive staining cells of chitosan-pGJA-P transfected cell is more than that of naked plasmid transfect cells, but less than that of Lipofect-DNA complex group. Chitosan was found to be less cytotoxic compared with lipofectin (p<0.01).
With processes of arc melting, inductive melting and copper mold suction casting, a plate Febased bulk amorphous alloy Fe60Co8Zr10Mo5W2B15 with a thickness of 1 mm was prepared. The surfaces and fractures of the cast bulk amorphous alloy were aglean and with typical metallic luster. The glass transition temperature (Tg), supercooled liquid region (δTx) and reduced glass transition temperature (Tg) of prepared Fe-based amorphous alloy are 884 K, 63 K, and 0.611 respectively. The fracture toughness of the cast bulk amorphous alloy is at the level of 1.6 MPa·m1/2.
The influence of a key process variable on the mold filling characteristics of AZ91 Mg-alloy was studied in the low pressure EPC process. The applied flow quantity of insert gas from 1 to 5 m3/h associated with the pressurizing rate in the low pressure EPC casting process was considered for rectangle and Lr shape plate casting. The experimental results show that there is an optimal flow quantity of insert gas for good mold filling characteristics in AZ91 Mg-alloy low-pressure EPC process. The optimal flow quantity of insert gas for the specimens is 3 to 4 m3/h. Either less or higher than the optimal flow quantity of insert gas would lead to misrun defects or folds, blisters and porosity defects. The practice of hub casting confirmed that the low-pressure EPC process with an optimal processing variable exemplified as 4 m3/h gas flow quantity was capable of producing complicated magnesium castings without misrun defects.
By introducing a vibrating, force field into the extrusion process of polymer melt, an experimental equipment of constant velocity type dynamic rheometer of capillary (CVDRC) was designed. A set of experimental procedures was established, by which the dynamic rheological parameters of polymer can be acquired, and a set of data management methods to undergo time-domain or frequency-domain analysis was set up for dynamic rheological data of polymer melt. Meantime, the characterization formula of polymer melt’s rheological behavior in a vibrating force field was set up. The instantaneous value of capillary entry pressure, capillary volume flow rate and their phase difference were measured and analyzed, and the melt apparent viscosity, which describes the rheological behavior of polymer melt in a vibrating force field, was obtained.
A phenomenological model based on phase separation between ferromagnetic metallic and paramagnetic insulating domains was applied to analyze the electrical transport and colossal magnetoresistance for mixed-valent manganites of RE2/3 AE1/3 MnO3. The results show that the model can yield results in agreement with experimental observations in these manganites. The present approach provides a simple picture to visualize the reason that the temperature dependence of resistance (with and without applied magnetic fields) in these compounds has the peculiar shape, without invoking any complicated concept.
The synthesis and characterization of aluminum-pillared rectorite were studied. The synthesis was conducted with both conventional heating and microwave irradiation. Microwave irradiation was found to enhance the intercalation and ion-exchange during synthesis, and to be able to produce the rectorite with a larger d001 and a better uniformity. The specific surface area is 180 m2/g and basal spacing is 3.2 nm. The texture change and thermal and hydrothermal stability of cross-linked rectorite were examined using XRD, FTIR, nitrogen-adsorption and TGA. The experimental results show that the aluminum-pillared rectorite, after calcined at 800 °C for 3 hours, can keep the basal aluminum-silicate texture and would not disperse in water at room or an elevated temperature. The aluminum-pillared rectorite shows a high specific surface area, good thermal and hydrothermal stability, and is promising in applications as catalyst carriers and adsorbents for waste treatment.
The influence mechanism of the nano-apatite on the human hepatocellular carcinoma in vitro was investigated. Using the homogeneous precipitation method, the nano-apatite was synthesized at room temperature, and it was characterized with transmission electron microscopy (TEM) and the Zataplus. The influence on the expression of the c-myc and p53 gene in the human hepatocellular carcinoma cell lines were tested with the TEM and hybridization in situ. The TEM and the Zataplus analyses show that the nano-apatite is distributed homogenously in size and needle-shaped sizes, which ranges from 67.5 nm to 88.3 nm. It is found that the nanoapatitet increases the volume of the human hepatocellular carcinoma cells, makes extensive cytoplasmic vacuolization, the mitochondria swelling, chromatin, in nucleus dispersed partially and condensed around the nuclear membranes. The interspace in nuclear membranes were separated and even the cytoplasm dissolved. It is also found that the expression of the c-myc gene is inhibited, but the p53 is enhanced. The experimental results demonstrate that the nano-apatite enables the oncosis of the human hepatocellular carcinoma cells by down-regulation of the expression of the c-myc and up-regulation of the expression of the p53 in vitro.
The nanostrutured mesoporous silica materials MCM-41 with different pore sizes were synthesized by adding 1,3,5-trimethylbenzene (TMB) as assistant agent in the reactant mixture. The obtained samples were investigated by XRD, HRTEM, FTIR and N2 adsorptions. It is shown that the pore sizes, ordered degree and specific surface are increase effectively with the incremental addition of TMB in an appropriate range, but the (100) peak intensity of XRD pattern becomes weakened and the ordered degree decreases when the additive quantity continued to increase. With the addition of TMB in an appropriate range, the effective surfactant ion pair packing parameter, g=V/a0l, is mediated in the range of 1/3-1/2 with the increment of V and l, indicating that mesoporous silica is a well-ordered hexagonal structure. However, when the addition of TMB increases, g value becomes larger, which leads to a less long-range ordered structure for the uneven condissolution of TMB.
The phenomenon of crystallization was implemented in the synthetic V-bearing steelwork slag based on the composition of factory slag from the Masteel Co., and the possibility of undercooling as a technique to precipitate V-concentration phase was demonstrated. The effect of 20 wt% Al2O3 additive introduced into the slag on intensifing the precipitation was also investigated. X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX) were used to investigate the slag after heat treatment. It is demonstrated that gehlenite and grossite are the major crystalline phases. Whitlockite with a high content of V2O5 (called V-concentration phase hereafter) nucleates homogenously and hetergenously and grows with decreasing undercooling. At 1548 K, the crystals of V-concentration phase grow up as the duration of time, with a medium grain size of 25 μm at 300 min holding time.
The density of liquid Ni−Ta alloys was measured by using a modified sessile drop method. It is found that the density of the liquid Ni−Ta alloys decreases with the increasing temperature, but increases with the increase of tantalum concentration in the alloys. The molar volume of liquid Ni−Ta binary alloys increases with the increase of temperature and tantalum concentration.
According to the theory of the stochastic trajectory model of particle in the gas-solid two-phase flows, the two-phase turbulence model between the blades in the inner cavity of the FW-Φ150 horizontal turbo classifier was established, and the commonly-used PHOENICS code was adopted to carried out the numerical simulation. It was achieved the flow characteristics under a certain condition as well as the motion trace of particles with different diamenters entering from certain initial location and passing through the flow field between the blades under the correspondent condition. This research method quite directly demonstrates the motion of particles. An experiment was executed to prove the accuracy of the results of numerical simulation.
Silicon dioxide sol was synthesized by silicon in the presence of alkali catalyst. SiO2 nanoparticles (size in 8–15 nm) aqueous dispersion was prepared by using dispersion and surface modification in situ. The effects of reaction time, temperature, medium pH value, dispersant and surface-modifier on their diameters, sizes distribution and dispersion stability were also studied. The experimental results show that the preparation method can effectively resolve the dispersion stability of SiO2 nanoparticles in water.
When raw materials were preheated to 1000–1300°C by electricity and microwave was inputted for 1 min 5 s-4 mins, then alunminate clinkers were obtained. The f-CaO contents, XRD patterns and lithofacies analysis show that the microwave processing accelerates the clinkering reaction, and Fe2O3 is contributed to the aluminate cement clinkering. The appearance of liquid phase in process of microwave heating increases the microwave absorbability of materials greatly.
The influence of anti-freezing admixture on the alkali aggregate reaction in mortar was analyzed with accelerated methods. It is confirmed that the addition of sodium salt ingredients of anti-freezing admixture accelerates the alkali silica reaction to some extent, whereas calcium salt ingredient of anti-freezing admixture reduces the expansion of alkali silica reaction caused by high alkali cement. It is found that the addition of the fly ash considerably suppresses the expansion of alkali silica reaction induced by the anti-freezing admixtures.
In order to unclose the dynamics of SPS densification, a special sintering sample (Cu/Ti wires compact) was designed. Characters of the shrinkage rates during sintering process and microstructures of products fabricated by the spark plasma sintering (SPS) and hot-press sintering were investigated. The experimental results reveal that a higher temperature field is formed at the connected area and conductive net of the compact. These high-temperature parts deformed more easily than other parts, which is believed to be the main cause of SPS fast densification, according to a hard-core and soft-hell material model.
For the purpose of reducing the volumetric shrinkage and volumetric shrinkage variation, the process in injection molding of aspheric plastic lens was simulated, and several process parameters which include holding pressure, melt temperature, mold temperature, fill time, holding pressure time and cooling time were optimized by using an orthogonal experimental design method. Finally, the optimum process parameters and the influence degree of process parameters on the average volumetric shrinkage and the volumetric shrinkage variation are obtained.
TiB2 ceramics powder was synthesized from B2O3−TiO2−Mg system. The effects of TiB2 addition as diluent on the combustion synthesis process were investigated. The results of thermodynamic calculation and experiments show that the increase of TiB2 content ranging from 0 to 20wt% can reduce the adiabatic temperature Tad from 3100 K to 2896 K and combustion temperature Tc from 2139 K to 1621 K respectively. The particle size and half width of the particle distribution are also increased with the addition of TiB2 increasing from 0 to 20wt%. The combustion product is a mixture of TiB2, MgO, and other intermediate phases. The leached product contains mainly TiB2, TiO2 and TiN, and its oxygen content is 7.77wt%.
A model was presented to describe the microstructure evolution during the directional solidification process. In this model, the problem of different properties in the solid and liquid phase was solved by making the properties continuous at the solid/liquid interface. Furthermore, a random noise was incorporated to reflect the anisotropic growth. Moreover, the averaging solute conservation was developed to keep the total solute conservation in the interface region. A simple ingot was simulated by this method, the model can represent the microstructure evolution, solute concentration redistribution, micro-segregation and the columnar-to-equiaxed transition.
The flow field in a cold model of 2500 t/d five-stage cyclone preheater and precalciner system was numerically simulated. Renault stress model (RSM) turbulent model was adopted to simulate the flow field, and a hybrid mesh scheme was selected to generate calculation mesh. With the first order upwind difference, finite-volume method was used to convert turbulent equations into difference equations pressure-velocity coupling which were solved by the classic simple algorithm, and during the course of numerical solution, mesh self-adapting technology was applied. The main flow field structures of the whole system and each part of the cold model were studied by analyzing the simulation results.
Electrical emission (EM) signals, which are generated from the concrete specimens under three-point bending tests, were conducted. It is shown that electrical emission phenomena are related to cracking of the specimens, cohesive failure, contact-separation etc. The simultaneous appearance of electric emission signals and visible cracks during the flexure loading of beams was also observed.
The antibacterial effect of carrying silver B2O3−SiO2−Na2O glass material was studied by means of antibacterial ring, nephelometery, MIC value, thin film attachment and microcalorimetry, respectively. The experimental results of five kinds of antibacterial test methods are almost identical and can verify that carrying silver B2O3−SiO2−Na2O glass material exerts an excellent antibacterial performance. Antibacterial ring and nephelometery are simple, quick, but the precision is restrictive. MIC value, thin film attachment method and microcalorimetry can quantitatively compare the antibacterial effects of the antibacterial glass material. Compared with the traditional microbe test methods, the microcalorimetry can analyze the inhibiting effect of the cell’s growth and metabolism on the antibacterial glass material by monitoring the thermal effect continuously and automatically.
The components of expansive soil were analyzed with EDAX, and it is shown that the main contents of expansive soil in the northern Hubei have some significant effects on engineering properties of expansive soil. Furthermore, the soil modified by lime has an obvious increase of Ca2+ and an improvement of connections between granules so as to reduce the expansibility and contractility of soil. And it also has a better effect on the modified expansive soil than the one modified by pulverized fuel ash.
New mathematical diffusion models for solid state homogenization of dendrite segregation were presented to calculate the concentration evolution of alloying elements during solid-state homogenization of dendrite segregation in any cross section of a three-dimensional dendrite system. With mathematical accumulation, all the individual concentration profiles of every dendrite can be accumulated to form a concentration equation, which may be required by sine model or not. Then diffusion homogenization processes for any cross sections of dendrites in solid state can be calculated from the equation. The only assumption of the new models was that any individual concentration profile in a dendrite system could be simulated by Gauss equation of Fick-2 law.
The permeability of lightweight aggregate concrete was studied. Some efforts were taken to increase the resistance of lightweight aggregate concrete (LC) to water penetration by using the mineral admixtures of fly ash, granulated blast furnace slag or silica fume. Accelerated chloride penetrability test and liquid atmosphere press method were used to study the anti-permeability of lightweight aggregate concrete. The experimental results show that fly ash, granulated blast furnace slag and silica fune can decrease the permeability of lightweight aggregate concrete, but the effect of granulated blast furnace slag is poor. According to the SEM and pore structure analyzing results, an interface self-reinforcing effect model was presented and the reinforced mechanism of mineral mixture on LC was discussed according to the model described by authors.
With the loading test equipment of corrosion fatigue specially designed, the corrosion fatigue characteristics of high performance concrete (HPC) withstanding the interaction of third point fatigue loading and Na2SO4 solution were investigated and analyzed. The experimental results indicate that water-binder ratio evidently influences the corrosion fatigue characteristics of HPC, and a moderate quantitative fine mineral admixture enhances the corrosion fatigue resistance of HPC. The effect is more significant when fly ash and silica fume are added.
A systematic research on the pyrolysis process of polymethysilicone (SAR-2) and the thermostability of the pyrolysis residue was made by the thermogravimetric analysis, DTA and infrared spectroscopy. The experimental results indicate that the pyrolysis residue of SAR-2 converted into the amorphous SiCxO4−x phase above 900°C, the residue at 1200°C is the most thermostable and antioxidant. It is suitable to be used as polysilicone preceramic.
Modified recycled aggregates were prepared with three different cement-admixture grouts. The physical properties, such as water absorption, apparent density, crushing index, slump and compressive strength of the recycled aggregate and the recycled concretes were tested, and the tests for the compression-deformation behavior of the concretes were also performed. The experimental results show that the cement-Kim powder grout is satisfied for enhancing the recycled concrete, and the modification of the recycled aggregate with the grouts can improve the toughness and the deformation ability of the concretes.