Applied Mechanics and Materials Vols. 395-396

Abstract: The intergenic spacer 1 (IGS1) region in rRNA gene of Auricularia auricula was PCR-amplified and sequenced, and the sequence was analyzed by using bioinformatics technology. The two-way sequencing results were spliced by DANMAN software and used MEGA5.10 to analyze sequence variability, calculate genetic distance and construct phylogenetic tree. The amplified fragment length of intergenic spacer 1 (IGS1) gene was about 954bp ~1162bp, GC content of 51.90 to 52.02%, 73 nucleotide variable sites, 16 parsimony informative sites. Variable sites were mainly concentrated in the201~232bp and 714~884bp region. IGS1 sequences have great extent Compared with other 9 species from the GenBank according to the analysis of distance matrix, the genetic relationship between strains and the related known species from systematic dendrogram, IGS1 sequence analysis supports the traditional classification of Auricularia based on morphology. IGS1sequences variation could distinguish the difference between Araucaria species, it could be used as a supplement study genetic diversity method.

Abstract: Used sequence diversity of chloroplast rbcL gene sequence to analyze Lilium phylogeny, structured model of the rbcL protein secondary structure and tertiary structure form Lilium superbum. There were 26 variable sites and 12 parsimony-informative sites by analyzing 1378bp rbcL sequences of 17 Lilium species. The main nucleotide variable type was base transversion. The main variable region form 560bp to 852bp and form1200bp to1371bp. Structured phylogeny tree with N-J method, four types of the 17 Lilium species were clustered, respectively Asian hybrid group, American hybrid group (two branches), and longiflorum hybrids group. Longiflorum hybrid system (nine Lilium species ) was divided into four sub-categories. Structured protein secondary structure of rbcL protein of Lilium superbum, there were 18 alpha helixes, 17 beta sheets and some turn angles. The hydrophobic analysis was hydrophilic protein. 3D model was structured by homology comparative SWISS-Model online. The scores of most amino acid residues in the 3D conformation of the rbcL protein were positive and within are asonable range.

Abstract: According to a company's actual process of producing coatings, Finite Element Method is adopted to simulate and analyze the variation rules of various fields and mechanical parameters during the preparing process of solar spectrum selective absorbing coating for medium-high temperature application using magnetron sputtering. The results show that during the process of magnetron sputtering, magnetic fields uniformly distribute around the target and the sputtering etching area can be a wide range of 180°. In the spaces for magnetron sputtering, the magnetic flux is maximum at the contact between the and the core, and the magnetic flux density distributes uniformly between the magnetic steel and the target; the magnetic induction distribute uniformly within the120°direction of the target and forming two planar track typed etched channels; when the cylindrical target rotates at a proper speed, a large area of coating in uniform thickness can be deposited on the matrix. The results provide theoretical guidance for actual production of preparing medium-high temperature selective absorbing coating of uniform thickness and excellent quality.

Abstract: In this paper, MCrAlY bonding layer was prepared through high velocity-oxygen fuel spray on the AZ91 magnesium alloy surface. 8wt%YSZ ceramic layer was deposited on the surface of bonding layer through atmospheric plasma spraying. The coatings were characterized by XRD and SEM. The hardness of the coating was tested. The coefficients of thermal expansion of the coating were measured through TMA. It was found that there were un-melted 8YSZ particles surrounded by melted particles layer by layer. Parts of ZrO₂ transited from cubic to tetragonal. The microhardness of the YSZ coating and bonding layer were 832.1Hv_0.3 and 700.3Hv0.3, respectively. The coefficients of thermal expansion of the magnesium alloy, MCrAlY layer and YSZ coating were 42.46 ×10^-6·k^-1, 15.26 ×10^-6·k^-1, 9.28 ×10^-6·k^-1, respectively. The bonding coat matched the magnesium alloy substrate and the YSZ coating well. The dimension of AZ91 magnesium alloy sample was very stabilized before and after coating deposition.

Abstract: The hot-dip galvanizing coating can promote the anti-corrosion performance of the bolts in outdoor steel structure engineering. But the anti-corrosion performance cannot match that of the steel due to the centrifugal process. In this paper, the anti-corrosion performance of four kinds of bolts obtained from different company was researched by the neutral salt spray test method. The results show that the anti-corrosion performance of the all four bolts was unsatisfactory. The reasons were studied through testing the thickness of the coating, coating uniformity, surface morphology and elemental composition. The results show that the causes are the lower thickness of the hot-dip coatings, too much defects on the surface of the coatings and the elemental composition impurity.

Abstract: 4Cr13 martensitic stainless steel coatings with different amount of V/Nb were prepared on the surface of the Q235 low-carbon steel by high velocity arc spraying (HVAS). The microstructure and properties of the coatings were characterized and tested by scanning electron microscope (SEM), X-ray diffraction (XRD), optical microscope, microhardness tester and wear tester. And the wear mechanisms of the coatings have been studied. The results showed that optimal percentage of V/Nb could improve performance of the coatings. The coatings had good forming properties, uniformity of microstructure and compact structure.The highest value of adhesion strength was up to about 36.80 Mpa. The hard particles could incease the hardness and wear resistanc of the coatings.The average microhardness was about 523 HV_0.1, higher than that of 4Cr13 coatings, and the abrasive wear resiatance was enhanced because of the added elements V and Nb. Key words: alloying coatings; 4Cr13; V/Nb; high velocity arc spraying (HVAS); abrasive behaviour

Abstract: This study investigated the use of nanoscale bilayers assembly film for hydrophilic surface modification on stainless steel plates and observed its effects on the evaporation of acetone and ethanol on the plates. This study first established the nanoscale bilayers assembly technique, and then performed hydrophilic surface modification on stainless steel plates by changing the surface structure, producing different contact angles. The relationship between the number of bilayers (10, 20, and 30) and the resulting contact angle was empirically determined; results indicated that 20-bilayer modification yielded the best result, reducing the contact angle from 70° (unmodified surface) to 12°. Beyond 20 bilayers, at 30 bilayers, the samples show no significant changes or improvements to contact angle or hydrophilicity. Results from evaporation time tests showed that, compared to the evaporation time of ethanol and acetone on unmodified flat stainless steel surface, this decreased contact angle can improve the evaporation time by 100%, clearly indicating that hydrophilic surface modifications causes significant improvement in evaporation.

Abstract: An arc-sprayed oxidation protective barrier coating system on austenitic stainless steel is composed of an inner Ni-Cr-Ti alloy layer and a pure aluminum outer layer. The high-temperature oxidation behavior of the coatings on 304N substrate was investigated during isothermal exposures in air at 1100°C. Experiments showed that interdiffusion of alloying elements within the protective coatings occurred, and the elements, Cr,Ni and Al, were also diffusing into the substrate metal. As test time proceeded, aluminum nitrides were generated in situ in the substrate, which had a layer-like distribution. The nitrides generated play the roles as element diffusion barriers, and together with the surface alumina they provide a long-term effective anti-oxidant protection to the steel substrate. The coatings on 304N substrate were not deteriorated and the substrate was protected well, being exposed to 1100°C for 350 hours. The analysis results of oxidation kinetics showed that the specific mass changes of the coated specimens were much smaller than those without coatings.

Abstract: Ice jet technology shows a promising prospect of application in surface cleaning and de-painting engineering because of its environmentally friendly feature. The main objective of this work is to present a deeply experimental study on the organic paint removal from aluminum alloy 2A12 substrates and the surface damage development using ice jets. The effects of ice blasting pressure and blasting time on de-painting and damage to the substrate were mainly concerned. It was shown that at blasting pressure of 0.2MPa, organic paint coatings were stripped from the 2A12 substrates. The paint coatings, moreover, were removed more effectively with increasing blasting pressure. Little changes of the roughness of the blasted substrate surface were observed. SEM images showed little plastic deformation at the blasting pressure of 0.5MPa existed on the surface. Whereas, a few of impact craters due to impact of high-velocity ice particles appeared at 0.7MPa for 7 seconds of exposure time with its number increasing obviously for 15seconds.

Abstract: In order to know the coating effect and application of color ink-jet paper, the coating formula and printing quality of ink-jet paper were deeply studied. First of all, the coating liquid was prepared by dispersing and mixing the nanometer pigment, the adhesive and the other additives. Then the properties of ink-jet paper were tested and their surface profiles were characterized and evaluated with scanning electron microscope. Finally, the coating paper samples and the base papers were all printed with color ink-jet printer and measured with a spectrodensitometer. The study result showed that it can gain well coating and printing quality when the ratio of SiO₂ and TiO₂ is 3:1 and the content of PVA adhesive is 50%, especially paper whiteness is obviously higher than that before the coating.