Advanced Materials Research Vols. 239-242

Abstract: Silk/PLA mixture is a new textile material, and it combines the outstanding characteristics of silk and PLA fibers. During the wet process, this mixture is subjected to some problems owing to the poor resistance of PLA fiber to alkali. The silk component in this mixture can be dyed with acid dyes under acidic condition, and with reactive dyes under alkaline condition. In the present work, silk/PLA mixture was dyed with Everzol ED reactive dyes in the case of the use of sodium carbonate and sodium bicarbonate as alkalis for the fixation of dyes. The alkali dosage and dyeing temperature on the uptake of dyes by this mixture were discussed. Also, the dyeing rates, building-up properties and color fastness of reactive dyes were determined. It was found that Everzol ED reactive dyes exhibited good dyeing properties for silk/PLA mixture under weakly alkaline condition in the presence of sodium bicarbonate.

Abstract: With zinc acetate and sodium hydroxide used as raw materials, while polyethylene glycol employed as dispersant agent, ultrafine zinc oxide flowers were successfully synthesized by hydrothermal method. The influence of the concentration of PEG20000 on the morphologies of ZnO flowers was discussed. The as-synthesized ZnO flowers consisted of microrods with hexagonal morphologies. The crystal structure and ultraviolet absorbing performance of ZnO flowers were also characterized using XRD, UV-VIS absorption spectrum. The results indicate that ZnO flowers are hexagonal wurtzite structure with high purity. There is a strong excition absorption peak at 300 nm in UV-VIS absorption spectrum and blue shift existed obviously.

Abstract: This study investigates the applicability of p-type NiO in the working (or counter) electrode of a dye-sensitized solar cell (DSSC). The working electrode was designed and fabricated by depositing a film of TiO₂/NiO composite particles, which were prepared by mixing the Ni powder with TiO2 particles using dry mixing method. The counter electrode was fabricated by depositing a NiO film on top of a Pt film, which has been deposited on a FTO glass using an ion-sputtering coater (or E-beam evaporator). This study shows that the power conversion efficiency of the DSSC with TiO₂/NiO composite particles (3.80%) substantially exceeds that of the conventional DSSC (3.16%) due to the effects of the NiO barrier and the n-p junction. Aside from this, the power conversion efficiency of a DSSC with a Pt(E)/NiO counter electrode (4.28%) substantially exceeds that of a conventional DSSC with a Pt(E) counter electrode on which a Pt film was deposited using an E-beam evaporator. This result is attributed to the fact that the NiO film coated on the Pt(E) counter electrode improves the electrocatalytic activity of the counter electrode.

Abstract: Electrochemical migration (ECM) tests and rapid whisker growth on Sn-3.0Ag-0.5Cu solder candidates doped with Zn and Bi on Cu-plated FR-4 printed circuit board were conducted by applying constant voltage. The results showed that dendritic shape were different when the doped metals were different. When Zn was doped in SAC solder, dendrites looked like tree trunk, while that of Bi doping looked like rose, which was due to the different composition of SAC candidates. Comparing the length of dendrites at the same condition, it could be concluded that dendrite growth might be suppressed by Bi addition, which the contrary effect suitable to Zn addition. EDAX results showed that the main content on dendrites was Sn with or without Bi doping, while the main content was Zn, Sn, and Ag with Zn doping and Zn/Bi dopings. Whisker growth test verified that Sn accounted for a majority (larger than 95wt.%), no difference could be seen on whiskers of SAC solder candidates although the contents of SAC solder candidate were differently. The whisker growth rate were not different although the doped metals were different largely. Both dendrite growth and rapid whisker growth of SAC solder candidates doped with Zn and Bi were harmful to micro/nanoelectronic packaging attributing to bridge short circuit in PWBs industries.

Abstract: For the preparation of the self-healing phase B_xC with BCl₃-CH₄-H₂ precursors, the production has been examined as a function of the initial gas ratios of BCl₃/(BCl₃+CH₄) and H₂/(BCl₃+CH₄) at given temperature and pressure. The results show that the composition of the condensed phase is quite sensitive to the molar ratio of BCl₃/(BCl₃+CH₄) and H₂/(BCl₃+CH₄). The ideal condition for the deposition of B_xC is that the ratio of BCl₃/(BCl₃+CH₄) is 0.8 and the H₂/(BCl₃+CH₄) ratio ranges from 10 to 10^5.2. The carbon or boron-rich material is mainly controlled by the ratios of BCl₃/(BCl₃+CH₄) and H₂/(BCl₃+CH₄). The deposition condition of carbon-rich phase should be in low BCl₃/(BCl₃+CH₄) (0.0~0.8) and H₂/(BCl₃+CH₄) (10^-2<10²) ratios, whereas that of the boron-rich phase needs high BCl₃/(BCl₃+CH₄) (0.8~1.0) and H₂/(BCl₃+CH₄) (10⁴~10⁵) ratios.

Abstract: Flexible functional layer of asphalt sands setting between concrete pavement slab and base can change the contact state of different layers and reduce the friction coefficient between slab and base and the thermal stress of pavement slab can be decreased. This functional layer can also protect the base from void disease produced by infiltration and erosion of rain water and snow water. This paper mainly focuses on the impact of parameters variation of contact state of pavement structural layer, slab length and flexible asphalt functional layer thickness and modulus for concrete pavement thermal stress to provide some basis for the selection of flexible functional layer of concrete pavement structure. Calculation results show that interlayer friction coefficient has relatively obvious effect on thermal stress of pavement structure; setting a functional layer can reduce the slab thermal stress evidently. Slab thermal stress and base thermal stress increase non-linear with the growth of slab length. The thickness variation of the functional layer has a slight impact on the concrete slab thermal stress. The higher the modulus of the functional layer is, the greater the slab thermal stress is.

Abstract: Reflective topcoat and thermal insulation mid-coat composite coatings system was used in this work. The effect of the content of the hollow glass micro-beads and rutile titanium dioxide on the heat insulation performance and the reflectivity of the coatings were investigated, respectively. The heat insulation performance and the reflectivity of the thermal insulation reflective composite coatings (TIRCCs) were characterized by self-prepared experimental device. The results showed the good heat insulation property, and the insulated temperature reached 12-15°C, and the reflectivity was up to 95%. The anti-corrosion and anti-penetration of the TIRCCs were studied by electrochemical impedance spectroscopy (EIS) technique. The results showed that the resistance of the TIRCCs still be maintained at 10⁸Ω·cm² after 30 days in the 3.5% aqueous solution of sodium chloride. So The TIRCCs can be used on the surface of the steal structure for decreasing the temperature and enhancing anti-corrosion properties.

Abstract: The functionalized porous hybrid silica as a separation medium was synthesized by using Cetyltrimethyl Ammonium Bromide(CTAB) as template, (3-aminopropyl) triethoxysilane (APTES) and tetraethyl orthosilicate (TEOS) as reactive monomer, with the existence of ammonia, reacting for 80 h at 80°C. The influences of the main reactants ratio and the pH of reaction on the structure of the materials were investigated through the characterization by Fourier-Transform infrared spectrometer (FTIR), scanning electron microscope (SEM) and pore structure measurements. And the best reaction conditions were optimized. The monolithic column made by this porous hybrid silica has been applied to separate benzylideneacetone and o-chlorotoluene, which are the main composition in electroplating additive.

Abstract: Cobalt oxyhydroxide nanocrystals were synthesized in an aqueous solution in the cavity of the apoferritin from horse spleen (HsAFr), and two-dimensional CoOOH-ferritin nanodots were prepared by simple touch method on modified silicon surface. In the synthesis, CoOOH nanocrystals are encapsulated and growth is restricted to the internal dimension of the protein cavity. The obtained nanodots were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), absorption and photoluminescence (PL) measurements. From the results, it was concluded that CoOOH nanocrystals were successfully synthesized in the core of ferritin and the monolayer of CoOOH-ferritin could be obtained on the surface of modified silicon surface. In addition, CoOOH quantum dots(QDs) in ferritin core provided the PL emission peak. Accordingly, the CoOOH-ferritin arrays can be employed as a potential useful biosensor material for PL technique.

Abstract: Rate-dependent hysteresis existing in the magnetostrictive actuator usually causes undesirable inaccuracies or oscillations and even instability of the controlled system. So an intelligent modeling method, which is based on modified online least squares support vector machines (MOLS-SVM), is proposed in this paper to describe the rate-dependent hysteresis in magnetostrictive actuator. The model is fast and does not require tremendous computational efforts. The data measured in the experiment are used for modeling. The results obtained by using the proposed model are in good agreement with experimental results.