Jianzhong Yao

Ductile Fe-Nb-B bulk metallic glass with ultrahigh strength

The authors report a simple Fe-based Fe(71)Nb(6)B(23) ternary bulk metallic glass with a record high strength of 4.85 GPa as well as an appreciable compressive plastic strain of 1.6%. This finding is associated with the unique attribute of the alloying element Nb, which favors the formation of a networklike structure and holds high Poissons ratio. A fracture feature with a combination of vein pattern and nanoscale corrugations under compression is clearly characterized in this glass. The fractographic observations correlate well with the observed improvements in plasticity. (c) 2008 American Institute of Physics.

Characterization of Fusarium graminearum inhibitory lipopeptide from Bacillus subtilis IB

Bacillus subtilis strain IB exhibiting inhibitory activity against the Fusarium head blight disease fungus Fusarium graminearum was isolated and identified. The major inhibitory compound was purified from the culture broth through anion exchange, hydrophobic interaction, and reverse phase high-performance liquid chromatography (RP-HPLC) steps. It was a 1,463-Da lipopeptide and had an amino acid composition consisting of Ala, Glx, Ile, Orn, Pro, Thr, and Tyr at a molar ratio of 1:3:1:1:1:1:2. Electrospray ionization mass spectrometry/mass spectrometry (ESI MS/MS) analyses of the natural and the ring-opened peptides showed the antagonist was fengycin, a kind of macrolactone molecule with antifungal activity produced by several Bacillus strains. Fluorescence microscopic analysis indicated this peptide permeabilized and disrupted F. graminearum hyphae.

The influence of Nb and Zr on glass-formation ability in the ternary Fe-Nb-B and Fe-Zr-B and quaternary Fe-(Nb,Zr)-B alloy systems

Glass-forming ability (GFA) in relation to microstructure evolution in the ternary Fe-Nb-B and Fe-Zr-B and quaternary Fe-(Nb,Zr)-B systems was systematically studied in a three-dimensional composition space. Through navigating, it was revealed that alloys with the optimum glass-forming ability (GFA) are coupled with composition regions surrounded by competing crystalline phases. Alloys Fe71Nb6B23, Fe77Zr4B19, and Fe-71(Nb0.8Zr0.2)(6)B-23 were illustrated to be the best glass formers in the ternary Fe-Nb-B and Fe-Zr-B systems and the quaternary Fe-(Nb,Zr)-B system, respectively, with a critical size for amorphous formation up to 2 mm. They were compared with the theoretical predictions on the basis of an efficient dense-packing model, and good agreements were obtained.

Product Distribution From Flash Pyrolysis of Coal in a Fast Fluidized Bed

The flash pyrolysis of Huolinhe coal was carried out in a fast-entrained bed reactor. The investigation focuses on the effects of pyrolysis temperature and particle size on pyrolysis product distributions and gas and liquid compositions. Increasing temperature results in an increase of the gaseous product. There is an optimum temperature on the maximum liquid yield, which is around 650°C. An increase in particle size leads to a decrease of liquid products. Some amount of phenol group was found in the liquid products, which may produce the chemicals with high value. The results provide fundamental data and optimal conditions to maximize light oils yields for the coal topping process.Copyright

Local slip velocity in a downer

Abstract Based on the EMMS model, the local slip velocity between gas and solid is systematically analyzed and a theoretical correlation of local slip velocity with local voidage for a downer is derived as follows: u s ( r ) u t = D 8 / 7 ( 1 - ɛ mf ) - 2 / 7 [ 1 - ɛ ( r ) ɛ ( r ) ] 8 / 7 ɛ ( r ) 47 / 14 ɛ ( r ) - ɛ mf ɛ ( r ) . Using this correlation, the local gas-solid slip velocity in a downer is calculated. The calculated results are well consistent with experimental data. In addition, the variation of the local slip velocity with its corresponding solid holdup is also discussed.

The conversion of acetol during the concentration process from wood vinegar

Acetol, as one of the components of biomass pyrolysis liquid, is a high value-added compound for medicine synthesis. If acetol can be extracted from the renewable pyrolysis liquid, much environmental and economic benefit may be obtained; but the instability of acetol makes its concentration difficult. To clarify what compounds are formed from acetol during the distillation process, the components in different distillation systems were analysed and the mechanisms of the conversions were speculated on. It was found that acetol may undergo aldol self-condensation reactions followed by a series of intramolecular dehydrations to form five-ring or six-ring compounds.

Radial Hydrodynamics of High Velocity Gas-Solid Down-Flow Fluidized Beds

Experiments have been carried out in a gas-solids co-current down-flow circulating fluidized beds. The radial profiles of particle velocity and solid concentrations were measured by a fiber optical probe. Local solid flux was calculated based on the measured local particle velocity and solid concentration. The influence of gas velocity and solid recirculation rate on the radial flow structure has been examined. The experimental results show that the radial flow structure at high gas velocity has its own prominent characteristics in comparison with that at low gas velocity.Copyright