Evaporation behavior of low carbon ferromanganese alloy melt at reduced pressure

The distillation of an industrial Fe-Mn alloy at a high temperature and under a low pressure was suggested as an efficient method for manufacturing high purity manganese in our study. This study examined the evaporation behavior of a low carbon ferromanganese alloy melt at reduced pressure. The melt temperature, pressure, initial specific surface area of the melt and reaction time were considered as experimental variables. The evaporation ratio of manganese increased sharply in the initial reaction and remained relatively constant under various experimental conditions. The evaporation rate of manganese increased with an increasing temperature and the initial specific surface area of the melt and decreasing pressure. The activation energy of the manganese evaporation reaction decreased with a decreasing pressure. The initial specific surface area of the melt had a lesser effect than pressure. An empirical equation was derived for the rate of manganese evaporation from a low carbon ferromanganese alloy melt.     

Fabrication of a two-step Ni stamp for blind via hole application on PWB

This study examined imprint lithography with a two-step Ni stamp to solve the laser process problems and simultaneously form a blind via and layer pattern. The Ni stamp was fabricated by electroplating on a dry-etched Si mold, made from a SOI (silicon on insulator) wafer, and pattern replication. For the pattern transfer of the Ni stamp, hot embossing was performed on SU8-coated BT and Si wafer substrates. The residual layer was of a uniform thickness with an embossed shape of acceptable squareness.     

Representations of finite fields and the Naini-Seberry partitioning problem

Safavi-Naini and Seberry suggested a subliminal channel based on partitioning a set /spl Gamma/ of the generator matrices of error-correcting codes. We give a systematic procedure to partition /spl Gamma/ into E/sub i/'s with |E/sub i/|=2/sup m/ for any m, which is more efficient than the method in Yang, C-N et al., (1997).     

Morphology-dependent antibacterial activities of Cu2O

Cubic and octahedral Cu₂O microcrystals were synthesized by the reduction of a copper-ligand complex solution with glucose under microwave irradiation using ethylenediaminetetraacetic acid (EDTA) and N,N,N′,N′-tetramethyl ethylenediamine (TMEDA) as ligands. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) confirmed that the surfaces of the cubic and octahedral of Cu₂O microcrystals had {100} and {111} lattice planes. The antibacterial activity of the Cu₂O microcrystals against E. coli was examined using optical density (OD) methods. The antibacterial activity of the cubic Cu₂O crystals was superior to that of the octahedral Cu₂O crystals. The mechanism of the specific morphology-controlled synthesis of Cu₂O and their morphology-dependent antibacterial activity are discussed.     

Near-field optical recording with nanocomposite cover-layer for numerical aperture of 1.85

Near-field optical recording media with a nanocomposite cover-layer were prepared and tested using a gap servo, near-field recording system with an effective numerical aperture of 1.85. The refractive index of the nanocomposite cover-layer, which has a smooth surface, is 1.86, yielding a successful gap servo operation. However, the recording density cannot be maximized due to the refractive index of the cover-layer being lower than the required value for the effective numerical aperture. A recording density of 95?GB per disc can be achieved with a nanocomposite cover-layer having a refractive index of 1.86. The readout signal from 110?GB is not clear due to the reduced eventual numerical aperture in conjunction with the limited refractive index of the cover-layer.     

Effect of surface treatment of ramie fiber on the interfacial adhesion of ramie/acetylated epoxidized soybean oil (AESO) green composite

Recently, many researchers have attempted to convert soybean oil into useful polymers. One of the ways to make soybean oil into a matrix of green composites is to modify its triglyceride structure to obtain the acrylated epoxidized soybean oil (AESO) through epoxidization and acrylation. In this study, the effects of ramie fiber surface treatments such as acetylation, silane, and peroxide treatments on the chemical, morphological, and interfacial adhesion properties of a ramie/AESO green composite were studied. Surface-treated fibers were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and dynamic contact angle analysis. The crystallinity and thermal stability of chemically treated fibers were investigated by wide angle X-ray diffraction and thermogravimetric analyzer. It was demonstrated that surface treatments lead to several morphological changes, including the formation of micro-cracks and removal of impurities by acetylation and peroxide treatment as well as surface smoothing by silane treatment. Surface energy of acetylated fiber decreased with treatment time and showed the lowest value for silane treated fiber. The interfacial shear strength (IFSS) of a fiber/AESO composite was investigated through the microbond test. The IFSS of silane treated ramie was higher than that of others. The result indicates that silane treated fibers improve the interfacial property, which is the most important characteristic for the end use of green composites.     

Correlation of microstructure with the wear resistance and fracture toughness of hardfacing alloys reinforced with complex carbides

A correlation was made of the microstructure, wear resistance, and fracture toughness of hardfacing alloys reinforced with complex carbides. The hardfacing alloys were deposited twice on a low-carbon steel substrate by a submerged arc welding (SAW) method. In order to investigate the effect of complex carbides, different fractions of complex carbide powders included inside hardfacing electrodes were employed. Microstructural analysis of the hardfaced layer showed that cuboidal carbides, in which a TiC carbide core was encircled by a WC carbide, and rod-type carbides, in which W and Ti were mixed, were homogeneously distributed in the bainitic matrix. In the surface layer hardfaced with FeWTiC powders, more complex carbides were formed, because of the efficient melting and solidification during hardfacing, than in the case of hardfacing with WTiC powders. As the volume fraction of complex carbides, particularly that of cuboidal carbides, increased, the hardness and wear resistance increased. In-situ observation of the fracture process showed that microcracks were initiated at complex carbides and that shear bands were formed between them, leading to ductile fracture. The hardness, wear resistance, and fracture toughness of the hardfacing alloys reinforced with complex carbides were improved in comparison with high-chromium white-iron hardfacing alloys, because of the homogeneous distribution of hard and fine complex carbides in the bainitic matrix.     

胎圈钢丝锡含量和胶料类型对橡胶界面形态的影响

钢丝帘线／橡胶界面的粘合层对改善粘合性能和保持轮胎稳定性的作用已得到广泛关注。近几十年来,对镀黄铜钢丝帘线粘合性能及其帘线／橡胶界面开展了很多研究。然而,对镀青铜胎圈钢丝粘合和橡胶界面方面研究很少。     

Surface hardening of a gray cast iron used for a diesel engine cylinder block using high-energy electron beam irradiation

This study investigates the effects of high-energy electron-beam (1.4 MeV) irradiation on surface hardening and microstructural modification in a gray cast iron currently used for a diesel engine cylinder block. The gray cast-iron samples were irradiated in air using an electron accelerator. Afterward, their microstructure, hardness, and wear properties were examined. The original microstructure, which contained graphite flakes in a pearlitic matrix, was changed to martensite, ledeburite, and retained austenite, along with complete or partial dissolution of the graphite. This microstructural modification occurred only when the surface was irradiated with an input-energy density over 1.1 kJ/cm², and it greatly improved the surface hardness and wear resistance. In order to investigate the complex microstructures, thermal analysis and simulation testing were also carried out. The results indicated that the irradiated surface was heated to the austenite-temperature region and then quenched to room temperature, which was enough to obtain surface hardening through martensitic transformation. The thermal analysis results matched well with the microstructures of the thermally simulated samples.