Finding of Gray Points on the Surface of the Sn-Fe Alloy Layer and Its Effects on the Corrosion Resistance of the Alloy Layer

After removing tin coating of tinplates offered by some steel works, we discovered massive, highly disperse gray points outspreading along rolling direction on the surface of the alloy layer. Morphology of the alloy layer was observed by scanning electron microscope (SEM), and many cavities of the alloy layer were found out in the gray point. After analyzing the composition of the alloy layer, we found that content of Fe in the gray points was more than that in the normal alloy layer. Moreover, corrosion resistance of the alloy layer declines with increase of amount of gray points. In addition, the hot-humidity testing was carried out for some plates whose surface has many gray points. After 14 days, there were many rust points occurring in the edge of gray points and in the small gray points. The morphology of rust points was observed by atomic force microscope (AFM). The reason why rust points generated in the edge of gray points and in the small gray points was discussed.     

Macroscopic Studies on the Properties of the Anodic Oxide Films on Titanium

The effect of fluoride ions on the formation and dissolution behaviour of anodic oxide films on Ti has been investigated in acidic fluoride media (pH=1) using impedance and galvanostatic techniques. A5 the fluoride ion concentration and temperature increase the rate of oxide film formation decreases while the dissolution process increases. oxide film formed at high tem-perature and formation voltage was found to contain more defect sites in the film than that formed at a lower one. Activation energies are calculated during the oxide film formation and dissolution and found to be 20.76 and 28.72 kJ/mol, respectively. Formation rate and reciprocal capacitance data are reported as a function of polarizing current density. Values are recorded for the electrolytic parameters A and B. Potentiostatic curves are derived from the galvanostatic results.     

Influence of Additive Silica on the Laser Melting of the Ceramic Coatings

The influence of additive silica on the microstructure of plasma sprayed Al2O3 and Al2O3 13 wt pct TiO2 ceramic coatings at laser melting has been investigated in this study ,At the laser melting ,additive silica in Al2O3ceramic coating can reduce the stress of cooling shrinkage generated during solidification ,Moreover,silica can render finer size of grains of the melting layer and form continuous glassy matter around the grain boundaries so as to reduce further the cooling stresses and to suppress the formation and spreading of cracks ,On the other hand,at the laser melting,TiO2 reacts with Al2O3 and transforms into TiAl2O5,The latter new phase has great and anisotropic coefficients of thermal expansion leading to big and asymmetrical stresses and thus to form cracks in the melting layer of Al2O3 13 wt pct TiO2 coating ,Due to the fact that the influence of additive silica on the suppression of the formation of cracks is rather limited and cannot counterbalance the negative effect of TiAl2O5,thus the melting layer of Al2O3 13 wt pct TiO2 coating doped with 3 wt pct SiO2 cracks also ,Nevertheless,TiO2 can greatly develop the wear resistance of the ceramic coating as sprayed or laser melted.     

In vitro study on the influence of strontium-doped calcium polyphosphate on the angiogenesis-related behaviors of HUVECs

Angiogenesis is of great importance in bone tissue engineering, and has gained large attention in the past decade. Strontium-doped calcium polyphosphate (SCPP) is a novel biodegradable material which has been proved to be able to promote in vivo angiogenesis during bone regeneration. An in vitro culture system was developed in the present work to examine its influence on angiogenesis-related behaviors of human umbilical vein endothelial cells (HUVECs), including cell adhesion, spreading, proliferation and migration. The effects of microtopography, chemical property and the ingredients in the degradation fluid (DF) on cell behaviors were discussed. The results showed that cells attached and spread better on SCPP scaffold than on calcium polyphosphate (CPP), which might partially result from the less rough surface of SCPP scaffold and the less hydrogel formed on the surface. In addition, cell proliferation was significantly improved when treated with SCPP DF compared with the treatment with CPP DF. Statistical analysis indicated that Sr(2+) in SCPP DF might be the main reason for the improved cell proliferation. Moreover, cell migration, another important step during angiogenesis, was evidently stimulated by SCPP DF. The improved in vivo angiogenesis by SCPP might be assigned to its better surface properties and strontium in the DF. This work also provides a new method for in vitro evaluation of biodegradable materials' potential effects on angiogenesis.     

Influence of Turbulence on the Deposition of Particles from a Gas‐Dispersed Flow on the Wall

Simulation of the scattering and deposition of dispersedphase particles in the region of interaction of a turbulent flow with an obstacle is considered. The regimes and distinctive features of deposition of particles in the vicinity of a critical point are investigated under different conditions. The sedimentation coefficient of the impurity is calculated as a function of the parameters of unperturbed flow and the particle size. The results of the calculations are compared to the data obtained without allowance for the influence of the fluctuations of the carrierflow velocity on the motion of the impurity.     

Investigation of the Dynamics of Evaporation of Condensed Bodies on the Basis of the Law of Spectral‐Radiation Intensity of Particles

The fundamentals of radiation theory and the mechanism of evaporation of condensed bodies are presented. The distribution functions of particles of a body by energies and by the intensity of their transition from one energy level to another in the process of evaporation have been obtained based on the law of spectralradiation intensity of the body particles. The temperature dependence of the resulting vapor flow on the outer surface of a massive condensed body and a thin layer in equilibrium and nonequilibrium states, which, in the limit, transforms to the known Hertz–Knudsen formula, has been found.     

Study on the Methods of Equipment Maintenance Management

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Computerized Simulation on the Structure of Cryolite-Alumina Melts

Monte Carlo calculations were performedon liquid ionic solution of saturated aluminain cryolite melt containing a total of 205 ions.The local structure and radial distributionfunctions of the melt were computerized by MonteCarlo method at 1283 K. It has been found thatthere exist the complex ionic clusters suchas AlOF_3~(2-), AlOF_4~(3-), AlF_4~-, AlF_5~(2-), AlOF_2~- etc.,as well as oxygen-bridge and flourine-bridgeionic clusters. In the melt studied, Al~(3+) ionstend to have preferential even coordinationnumber of 4F~- ions.     

Effects of TiO2 addition on the sintering of ZrO2·TiO2 compositions and on the retention of the tetragonal phase of zirconia at room temperature

The production of tetragonal zirconia polycrystalline (TZP) ceramics and the identification of factors controlling retention of the tetragonal phase in the ZrO₂·TiO₂ system have been investigated. In this binary system, it was not possible to retain tetragonal zirconia polycrystals at room temperature for a range of compositions sintered above 1200 °C. A decrease in the martensitic transformation temperature of zirconia with titania addition was observed, but the effect was insufficient to retain the tetragonal phase at room temperature. In solid solution, the TiO₂ additions act to suppress ZrO₂ densification, this leading to grain growth when attempts are made to attain higher densities. The use of fine powders, fast firing or sintering in reducing conditions altered densification but was not able to generate a final grain size sufficiently small to avoid spontaneous tetragonalmonoclinic transformation on cooling. Based on the results obtained for ZrO₂·MO_x systems, the main factors involved in the retention of tetragonal zirconia at room temperature are discussed in an attempt to incorporate thermodynamical and the stress field effects.     

Study on the effects of Cr2O3 on the reduction behavior of γ-Fe2O3

XRD and TG reduction analysis show that -Fe₂O₃ Fe-Cr catalysts, which contains 0.0 to 14.0 wt %. Cr₂O₃ and prepared by coprecipitating method, consist of crystalline -Fe₂O₃ and non-crystalline Fe₂O₃. Between 150–450 °C, three reduction stages are observed in the catalyst. The first stage is non-crystalline Fe₂O₃ reduced to non-crystalline Fe₃O₄, the second is crystalline -Fe₂O₃ to crystalline Fe₃O₄ and the third is non-crystalline Fe₂O₃ reduced to non-crystalline FeO. About 5 wt %. Cr₂O₃ can enter the lattices of -Fe₂O₃ to form solid solution. With the increasing of Cr₂O₃ content, the relative abundance of non-crystalline Fe₂O₃ and the amount of soluble Cr₂O₃ in non-crystalline increases, while the crystalline size of -Fe₂O₃ decreases.     

Study on the Modification of Nanodiamond with DN-IO

Fourier transform infrared spectroscopy （FT-IR） and ζ-potential were introduced to study the effect of different modification parameters on the surface properties of nanodiamond （ND）. Results showed that under stirring grinding grinding conditions, ND hard aggregates were smashed and some active spots on them reacted with surfactant molecules, which led to the increase in its ζ-potential and stability. Different models of surface modification were also given in this study.     

Properties of hydrothermally modified silica gels — Effect of the parameters of porous structure on the course of the modification process

The effect of the parameters of globular structure (diameter of globules and number of their contact points) on the course of a texture modification process has been examined. Modification of silica gels was carried out in an autoclave at elevated pressure in the temperature range 110–300°C and in a water vapour atmosphere. Silica gels having specific surface area of 64–830 m²/g and predominant pore radii of 40–1000 Å were modified. The mechanism of hydrothermal treatment is relatively complex. It depends, among other things on different parameters of globular texture, the temperature of a process and on the presence of different admixtures in the adsorbent being modified. Above 200°C the course of hydrothermal modification depends only slightly on the nature of the silica gel (narrow or wide porous).     

Effects of the Composition of Electrodeposited Fe-Ni-P Alloy on the Thermostability and Magnetic Properties

The magnetic properties, structure defects of electrodeposited Fe-Ni-P alloys with various compositions and the thermostability at amorphous state have been studied by DSC, positron annihilation and electronic integrating instrument methods. The results show that the thermostability of amorphous Fe-Ni-P alloys increases with Fe content. Emergence and recrystallization of stable phases defer as the P content of the coating increases. The minimum Hc, Br and Ph occur at 9.4 P (wt pct) content. Maximum Hc, Br and Ph occur at the weight ratio of Fe to Ni equaling to 1/9.     

Distinct element analysis of the effect of temperature on the bulk crushing of α-lactose monohydrate

Cryogenic milling could reduce the ductility in the milling operations of semi-brittle and relatively ductile pharmaceutical particles. However, to achieve a better application of this technology, it is necessary to establish the relationship between the influence of temperature on the mechanical properties and breakage characteristics of the single particle and the bulk crushing behavior of these types of material. The focus of this paper is on the analysis of bulk crushing behavior of α-lactose monohydrate particles in response to temperature variations, based on single particle mechanical properties and side crushing strength at different temperatures and the use of distinct element analysis. The effect of temperature on the side crushing strength of the particles has been quantified by quasistatic side crushing tests. The experimental results show a significant increase in the strength of the single particles by decreasing the temperature. These results are used in the distinct element analysis to simulate the bulk crushing behavior of pharmaceutical particles as affected by the temperature. The predictions are compared with the experimental results, for which a reasonable agreement is found for the ambient temperature case. There are some differences for the case of −20°C, due to lack of reliable data for Young's modulus.     

Pentaerythritol crystallization – Influence of the process conditions on the granulometric properties of crystals

The quality of crystals depends on many factors that determine their granulometric properties. In order to obtain crystals of desired size distribution, proper selection of the operating conditions is of a great importance. Commonly, the unseeded cooling crystallization is controlled by selecting the appropriate cooling profile. The crystallization process can also be controlled by adding a certain number of seed crystals of a uniform size in the crystallizer at the saturation temperature. This paper investigates the influence of the process conditions (mixing intensity, cooling profile, batch time, saturation temperature and seeding) on the granulometric properties of pentaerythritol obtained by batch cooling crystallization. All investigated process conditions influence the crystal size distribution (seeded and unseeded experiments). On the other hand, the shape of crystals was the same for all experimental conditions. Optimal cooling profile, lower retention time, higher mixing rate, and smaller initial seed surface area improves the final crystal size distribution.     

Studies on the Future of the Standardization for Tropical Agricultural Machinery

Tropicalcropsmainlyrepresentedbynaturalrubber,sisalhemp,sugarcane,cassava,coffee,pepperandcoconut,andtropicalfruitsrepresentedbypineapple,mango,banana,longan,litchiarespecialeconomicalcropsintropicalandsubtropicalregionsinourcoun-try.Tropicalagriculturalmachineryisthemachineryusedforplanting,managing,harvestingandprocess-ingtropicalcropsandfruits.Inrecentyears,tropicalagriculturalmachineryhasbeengrowingveryfast,andhasasignificantlypositiveeffectonthegrowthofagriculturaleconomyintropicalregions…     

Effect of Heat Treatment on the Corrosion Characteristics of Al-Li Alloys

Experiments were conducted to study the general room temperature corrosion characteristics of heat-treated and non-heat-treated Al-Li alloys with different Li compositions. Corrosion rate was measured using both the polarisation method and the weight-loss method. It was observed that the samples with higher Li content had lower corrosion resistance than those with lower Li content. Moreover, for all the specimens tested, it was fOund that heat treatment at 180℃ for 2 h (for the purpose of precipitation hardening) severely reduced the corrosion resistance,whereas heat treatment at 180℃ for 6 h significantly increased the corrosion resistance.