Advanced Materials Research Vol. 664

Abstract: To establish a methode for predicting the integral sensitivity of transmission-mode GaAs photocathodes, the relationship between X-ray relative diffraction intensity and integral sensitivity of GaAlAs/GaAs photocathode material is researched. After thermocompression bonding Si₃N₄/GaAlAs/GaAs/GaAlAs/GaAs epitaxial material to glass window in the vacuum condition, and chemically etching the GaAlAs buffer-layer and GaAs substrate, the glass/Si₃N₄/GaAlAs/GaAs photocathode module is formed. The X-ray relative diffraction intensity of the photocathode module is tested and calculated respectively, then the photocathode surface was activated in the ultrahigh vacuum chamber using the Cs-O activation technique. Following that, the integral sensitivity of the transmission-mode GaAs photocathode is measured by the spectral response measurement instrument in situ. It is found that the GaAlAs/GaAs photocathode material and photocathode module have similar X-ray relative diffraction shapes. The higher the similar degree of X-ray relative diffraction shape is, the bigger the X-ray relative diffraction intensity of photocathode module is, which results in the better photoemission capability and higher photocathode integral sensitivity. This method can be used as an evaluation criterion for the quality of transmission-mode GaAs photocathode module material.

Abstract: Silk fibroin is native fibrous protein extracted from silk. It has good mechanical properties because of its unique amino acid composition, complex of sequence characterization and the transform of crystalline structure under different condition. The characteristics of silk fibroin makes it better biological biocompatibility and biodegradability and have been used widely as biomaterials in the field of tissue engineering. Based on the introduction of its properties, the researches on the amino acid composition, sequence characteristics, molecular conformation, and its performance were reviewed in this paper.

Abstract: The Si-SiC nanocomposites have been synthesized by self-propagating high temperature synthesis (SHS) from natural precursors. The effects of difference amount of added NaCl from 0 to 0.75 moles to the reactants on the Si-SiC conversion and particle size were investigated. The reaction were carried out in a SHS reactor under static argon gas at the pressure of 0.5 MPa. The nanocomposite results have been characterized by scanning electron microscope, Transmission Electron Microscopy and X-ray diffraction. The results showed that the production of nano-composite materials using SHS process is feasible and agree well with the thermodynamics calculations.

Abstract: The removal of ammonia nitrogen in simulated wastewater with 90mg/L NH₄Cl was researched by ammonia stripping, electrochemical oxidation and the combination of the ammonia stripping and electrochemical oxidation. It is shown that the reduction of ammonia is enlarged with increasing of wastewater’s alkalinity during stripping. And the removal rates of ammonia nitrogen are 2.1% at pH2 and 43.1% at pH7 which is not related to the stripping time. The ammonia removal is higher efficiency in pH12 which is in the range of 45.1% and 61.4% when the stripping time is changed from 40 to 100 min. The removal rate of ammonia nitrogen is increased with the extension of electrolysis time by the way of the electrochemical oxidation. For 100min electrolysis, the ammonia removal in the cathodic and anodic compartments are 55.8% and 86.9%, respectively. Moreover, by using the ammonia stripping and electrochemical oxidation simultaneously, the ammonia removal in the cathodic and anodic compartments are up to 91.8% and 99.8% for 100min, respectively. The combining of the ammonia stripping with electrochemical oxidation technology has obviously synergistic effect in purifying ammonia nitrogen wastewater.

Abstract: The degradation of phenol was demonstrate with a novel two-layer type cathode (TTC). For the fabrication of TTC, chitosan was firstly deposited on foam nickel, then one piece of the resulting foam-Ni film and one piece of nanographite(Nano-G) composite film were fasten to obtain the two-layer type nano-G︱foam-Ni cathode. The electrolysis phenol was conducted by self-made cathode and the Ti/IrO₂/RuO₂ anode in the diaphragm cell. The results showed that in the diaphragm electrolysis system with the aeration conditions, the degradation rate of phenol reached 97.15% under 120min’s electrolysis, when current density was 39 mA/cm², initial pH value was 12 and electrolyte concentration was 0.1 mol/L. This two-layer type cathode could be reused without catalytic activity decrease, suggesting its potential application in the wastewater treatment.

Abstract: The Cu-deficient Cu(In,Ga)Se₂ (CIGSe) absorber layer for thin film solar cells was prepared by paste printing its powders followed by sintering at 550  650oC for 1 h with the assistance of sintering aid of 10% Te or 5% Sb₂S₃ to enhance densification. The variations of crystallinity, microstructure, composition, and electrical properties of resistivity, Hall mobility, and carrier concentration of CIGSe absorber layer with sintering temperature at different sintering aids were investigated. The advantage of this sintering process is the stability in composition and free of the problem of constituent vaporization. The major disadvantage of the CIGSe layer with 5% Sb₂S₃ as a sintering aid was a 5-time decrease in electrical mobility. Power conversion efficiencies of our devices with sintered CIGSe as an absorber layer were evaluated.

Abstract: In this study, the acute toxicity of brominated flame retardants decabromodiphenyl ether (decaBDE) on green alga Scenedesmus obliqnus has been investigated. Under laboratory conditions, low dosage of decaBDE (0.1, 0.2, 1, 5, 10 μg/L) can inhibit the growth of Scenedesmus obliqnus. The max inhibition rate was 27.39% by 10 μg/L decaBDE on day one. Chlorophyll contents were significantly inhibited by decaBDE. At the concentration of 10 μg/L, the inhibition rates of chlorophyll a and chlorophyll b were 68.1% and 86.0%, respectively. These results indicated that decaBDE pose toxicity on Scenedesmus obliqnus in the environment.

Abstract: The production cost of amorphous alloys by vacuum induction melting (VIM) was very high. In order to reduce the cost, in this paper, alloys were prepared in alkaline crucible protected with different slags by Air induction melting (AIM). The comparison was found out between VTM and ATM in the research by using optical microscope (OM), scanning electron microscope (SEM), EDS, etc. Experimental results showed that Fe-Si-B alloys can be prepared by AIM with economic and technical feasibility.

Abstract: XX Fe based alloy was the raw material to make amorphous strip by means of vacuum induction melting (VIM) which cost too much. To reduce the cost, an air induction melting (AIM) method was studied in this paper. In smelting process of the experiments, two kinds of crucible and different slag were used to prepare different samples. The inclusions in the samples were studied by using optical microscope (OM), scanning electron microscope (SEM) and energy spectrum analysis (ESA).The results showed that, by using alkaline crucible and appropriate slag, inclusions in the XX Fe based alloy can be controlled in a relatively low range.

Abstract: In this paper, X-ray computed tomography was applied to obtain the aggregate images of asphalt concrete sample. Fourier analysis was utilized to describe the surface characteristics of the aggregates. With complex Fourier series function, the shape of the aggregates was quantified. The results indicate that Fourier morphological analysis can be used to mathematically represent the shape of particles in 2D micromechanical simulation of asphalt concrete.