TaSi2 nanowires: A potential field emitter and interconnect

TaSi2 nanowires have been synthesized on a Si substrate by annealing NiSi2 films at 950 degrees C in an ambient containing Ta vapor. The nanowires could be grown up to 13 microm in length. Field-emission measurements show that the turn-on field is low at 4-4.5 V/microm and the threshold field is down to 6 V/microm with the field enhancement factor as high as 1800. The metallic TaSi2 nanowires exhibit excellent electrical properties with a remarkable high failure current density of 3 x 10(8) A cm(-2). In addition, effects of annealing temperatures and capability of metal silicide mediation layer on the growth of nanowires are addressed. This simple approach promises future applications in nanoelectronics and nano-optoelectronics.     

Preparation and characterization of colored electronic ink nanoparticles by high temperature-assisted dyeing for electrophoretic displays

The charged polymer nanoparticles of poly(methyl methacrylate-co-ethylene glycol dimethacrylate) were prepared by emulsifier-free emulsion copolymerization and aminolysis. Coloring on the nanoparticles was achieved by high temperature-assisted disperse dyeing. In the presence of a charge control and stabilizing agent, the colored PMMA nanoparticles showed the electrophoretic mobility because of the amine groups on their surfaces. The morphology and material characteristics of the colored polymeric nanospheres were also investigated.     

Selective growth of vertically-aligned ZnO nano-needles

Vertically-aligned zinc oxide (ZnO) nano-needles have been selectively grown on the Si (100) substrates using chemical vapor transport and condensation method without metal catalyst. The selective nucleation of nano-needles was achieved by the controlled treatment of substrate surface using zinc acetate aqueous solution. The nano-needles were selectively grown on the zinc acetate treated area, while the nano-tetrapod structures were formed on the non-treated area. The nano-needles have uniform tip-diameter and length, about 10 nm and 2-3 microm, respectively. The angle of the ZnO nano-needles from the substrate was 90 +/- 0.2 degrees. The structural and optical properties of nano-needles and nanotetrapod structures were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and photoluminescence (PL). The results showed that ZnO nano-needles grow along the c-axis of the crystal plane due to the c-oriented ZnO nanoseeds formed by zinc acetate treatment. The nano-needles have strong ultraviolet emission peak of 3.29 eV with green emission of 2.3 eV at room temperature. This selective growth technique of vertical nano-needles using aqueous solution method has potential applications in the field emission devices or optoelectronic devices hybridized with silicon based electronic devices.     

Sintering behavior and mechanical properties of WC–10Co,WC–10Ni and WC–10Fe hard materials produced by high-frequency induction heated sintering

The comparison of sintering behavior and mechanical properties of WC–10 wt.%Co, WC–10 wt.%Ni and WC–10 wt.%Fe hard materials produced by high-frequency induction heated sintering (HFIHS) method was accomplished using ultra-fine powder of WC and binders (Co, Ni, Fe). The advantage of this process allows very quick densification to near theoretical density and prohibition of grain growth in nano-structured materials. Highly dense WC–10Co, WC–10Ni and WC–10Fe with a relative density of up to 99% could be obtained with simultaneous application of 60 MPa pressure and induced current within 1 min without significant change in grain size. The hardness and fracture toughness of the dense WC–10Co, WC–10Ni and WC–10Fe composites produced by HFIHS were investigated.     

电镀及表面处理工业的目标、趋势及远景

可持续发展、产品稳定性及各种新的环保法律法规使电镀业面临新的挑战.本文介绍了几种新的环保技术--包括生物除油剂、电解除油自动添加系统、先进的离子交换系统及长效珍珠镍工艺等--的应用状况,探讨了电镀行业可持续发展策略.指出建立技术中心、开发新技术、发展绿色工艺是电镀业未来的发展方向.     

Combustion characteristics of the heat pellet prepared from the Fe powders obtained by spray pyrolysis

Fe powders for thermal batteries were prepared by reduction of iron oxide powders obtained by spray pyrolysis. The iron oxide powders prepared by spray pyrolysis had fine size, spherical shape and high surface area. The morphologies of the Fe powders were affected by the preparation temperatures of the iron oxide powders. The Fe powders obtained from the iron oxide powders prepared by spray pyrolysis at 900 and 1000 °C had slightly aggregated structure of the primary powders with several microns sizes. The powders had pure Fe phases at reducing temperatures between 600 and 800 °C. The heat pellets with diameter of 18.2 mm were prepared using Fe powders and potassium perchlorate (KClO₄). The porosity of the prepared heat pellet was about 40%. The break strength of the heat pellet was 0.9 kgf. The ignition sensitivity of the heat pellet was 4 W. The maximum burn rate of the heat pellet obtained from the Fe powders were 8.6 cm s^?1.     

Development of fibroblast culture in three-dimensional activated carbon fiber-based scaffold for wound healing

This work developed a novel bi-layer wound dressing composed of 3D activated carbon fibers that allows facilitates fibroblast cell growth and migration to a wound site for tissue reconstruction, and the gentamicin is incorporated into a poly(γ-glutamic acid)/gelatin membrane to prevent bacterial infection. In an in vitro, field emission scanning electron microscopy shows that rat skin fibroblasts appeared and spread on the surface of activated carbon fibers, and penetrated the interior and exterior of the 3D activated carbon fiber construct to a depth of roughly 200 μm. An in vivo analysis shows that fibroblast cells containing the proposed 3D scaffold had the potential of a biologically functionalized dressing to accelerate wound closure. Additionally, fibroblasts migrated to the wound site in a bi-layer wound dressing containing fibroblasts, enhancing fibronectin and type I collagen expression, resulting in faster skin regeneration than that achieved with a Tegaderm? hydrocolloid dressing or gauze.     

A simple drug anchoring microfiber scaffold for chondrocyte seeding and proliferation

The structural properties of microfiber meshes made from poly(2-hydroxyethyl methacrylate) (PHEMA) were found to significantly depend on the chemical composition and subsequent cross-linking and nebulization processes. PHEMA microfibres showed promise as scaffolds for chondrocyte seeding and proliferation. Moreover, the peak liposome adhesion to PHEMA microfiber scaffolds observed in our study resulted in the development of a simple drug anchoring system. Attached foetal bovine serum-loaded liposomes significantly improved both chondrocyte adhesion and proliferation. In conclusion, fibrous scaffolds from PHEMA are promising materials for tissue engineering and, in combination with liposomes, can serve as a simple drug delivery tool.     

IL-6 is an independent risk factor for resistance to erythropoiesis-stimulating agents in hemodialysis patients without iron deficiency

Anemia is a common complication in dialysis patients because of their relative erythropoietin deficiency. Despite treatment with erythropoiesis-stimulating agents (ESAs), some patients experienced ESA hyporesponsiveness. We evaluated the clinical and laboratory factors that affect ESA hyporesponsiveness and investigated the relationships between hepcidin, inflammatory markers, and the iron profiles of hemodialysis patients. Sixty-eight patients receiving hemodialysis at a single institution were evaluated in a cross-sectional study. The patients were divided into tertiles based on the ESA hyporesponsiveness index (EHRI), defined as the weekly ESA dose per kilogram of body weight divided by the hemoglobin level. The mean EHRI values for each tertile were 3.3 ± 1.2 (T1), 10.2 ± 2.9 (T2), and 24.5 ± 11.6 (T3). The mean serum erythropoietin levels were significantly higher in the Q3 and Q4 groups. Thus, patients with ESA hyporesponsiveness showed relative resistance to erythropoietin therapy. In univariate and multivariate analyses, patients in the third tertile of EHRI showed significantly higher mean interleukin-6 (IL-6) levels. Serum C-reactive protein (CRP) levels showed a similar trend, but the differences were not significant. Serum hepcidin levels tended toward lower mean values in the third tertile of EHRI. No relationship was observed between hepcidin and inflammatory markers or iron status. In conclusion, IL-6, but not CRP, is a strong predictor of ESA hyporesponsiveness in hemodialysis patients who have sufficient iron. It may be difficult to use hepcidin as an independent clinical marker because of the many factors that influence it and their interactions.