Advanced Materials Research Vols. 152-153

Abstract: By the researches and analyses of the fermentation type in the bio-hydrogen production system, ethanol-type fermentation bacteria had the largest H2-production capability, butyric acid type fermentation bacteria took the second place, and propionic acid-type fermentation bacteria had the least H2-poduction capability. When the organic loading rate (OLR) is 24kgCOD/m3•d, HRT is 8h and temperature is 35 °C, the highest hydrogen production capability corresponding were 4.2, 1.3 and 0.018 mol•kg MLVSS−1•d−1, so ethanol-type fermentation was optimal type for hydrogen production.

Abstract: In order to reduce the random noise influence on empirical mode decomposition (EMD), the original data is adaptively denoised by lifting wavelet transform to strain mode aliasing, avoid the pseudo mode functions and improve the quality in EMD. The method is employed to analyze the rotor oil whirl vibration signal. Obtaining intrinsic mode functions (IMFs), the instantaneous frequency and amplitude can be calculated by Hilbert transform. Hilbert marginal spectrum can exactly provide the energy distribution of the signal with the change of instantaneous frequency. Thus, the characteristics information of the rotor oil whirl vibration signal can be extracted effectively. Experimental result demonstrate the validity of the proposed method.

Abstract: Polymer composites inserted with high volume fraction of NiMnGa powders were fabricated and their magnetic-field-induced strain (MFIS) was investigated. It is found that MFIS of NiMnGa/polymer composites increases with the increase of volume fraction of NiMnGa powders in composites. Large MFIS of 950 ppm has been obtained along the orientation magnetic field while only 220 ppm was on the perpendicular orientation magnetic field.

Abstract: Photodegradation of ammonia by mixed-phase TiO2 nanoparticles, synthesized by the oxidation of TiCl4 in turbulent propane/air flame chemical vapor deposition (CVD) process, has been investigated experimentally by using a tubular photoreactor with thin TiO2 films coated on the reactor wall by sedimentation. Effects of ammonia initial concentration from 2-40mg/m3, relative humidity from 30-75%, rutile mass fraction from 20-50% of TiO2 nanoparticles on degradation degree are examined under the conditions of 38g/cm2 catalyst loading, 24mW/cm2 UV irradiation of 254nm, and 5.7sec residence time in the reactor. Results show that photocatalytic activity is higher when rutile mass fraction is from 0.2 to 0.4, corresponding higher PL intensity, and 60% conversion is achieved at initial ammonia concentration of around 5mg/m3 and 70% relative humidity. Based on experimental results, separation of photoinduced electron (e-) and hole (h+) pairs by rutile phase is discussed.

Abstract: The new reinforced concrete composite wall (RCCW) with inner insulating layer of polystyrene panel was developed to improve the durability of external thermal insulation plate on walls. The composite structure and construction method of the RCCW is briefly introduced in this paper. The thermal insulation behaviors such as conduct heat coefficient and total heat resistance of RCCW are tested by the protection chest method, the measured and calculated results of thermal insulation properties of the RCCW are compared with each other, the effect of heat-bridge resulted from connected concrete supports of specimen and bottom side concrete of specimen covering inner insulating layer on the test results is discussed.

Abstract: Recent research data on chondroitin sulfate have suggested that they have many new biological functions such as anti-atherogenesis, anticoagulation, prevention and cure of arthritis, protection and repair of neuron during CNS development, morphogenesis and cell division. They are widely applied to functional food, clinical medicine and biomaterial. However, these bioactivities and applications are dependent on their fine structure with different monosaccharide unit and sulfation patterns. This review provides information on intimate relationship between these biological functions and the structure. Moreover, we overviewed the newly analytical methods about the composition and fine structure of them, including chromatometry, high performance liquid chromatography, mass spectrum and nuclear magnetic resonance before and after enzymolysis.

Abstract: The microstructure, CVN toughness and micro-hardness of an X120 pipeline steel were investigated by metalloscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) etc. It showed that the microstructure evolved from lathe martensite, lathe bainite to granular bainite and polygonal ferrite, the size of M-A islands increased. With cooling velocity increasing, the CVN toughness at -20 was fluctuating, and reaching its peak in the steel cooled in oil had the best toughness, while the steel cooled in furnace was brittle at -20 . With cooling velocity decreasing, the micro-hardness of the steel decreased, whereas, the micro-hardness of the steel cooled in furnace increased slightly.

Abstract: The boron-doped nanocrystalline diamond films were prepared on Si(100) substrates by microwave plasma chemical vapor deposition in gas mixture of CH4/H2/trimethylboron (TMB) with B/C ratio in the range of 0-1900ppm. The dependencies of surface morphology, microstructure, phase composition and field electron emission properties on the B/C ratio were systematically investigated by scanning electron microscope, X-ray diffractometer, visible and UV Raman spectroscopy. The results show that the diamond grains gather together forming ball-like clusters with inhomogeneous size, the doped boron atoms can promote the growth of plane (111) surface and terminate the diamond growth sites, resulting in the reduction of growth rate with the increase of B/C ratio in the gas mixture. The two peaks located at approximately 500 and 1220cm-1 resulted from Fano interference were observed in the visible Raman spectra for the heavily boron-doped nanocrystalline diamond film, and the sp2/sp3 ratio of carbon bonds increased with B/C ratio increasing in gas mixture. The field electron emission performances of the boron-doped nanocrystalline diamond films were obviously dependent on B/C ratio in the gas mixture, and boron doping can improve their field electron emission properties remarkably. The low turn-on electric field of 7.6V/μm was achieved for the boron-doped nanocrystalline diamond film deposited at B/C ratio of 1900ppm.

Abstract: On the basis of Cam-clay Model, a proposal constitutive model on porous elasto-plastic geo-material was derived for the argillaceous shale, which was porous and easy to decompose with water, and then the mechanical behavior in an argillaceous shale tunnel was simulated. According to the mix theory, the argillaceous shale was analyzed as a three-phase mixture coupling with solid-liquid-air, and the effective stress was introduced to set up a proposal constitutive model. The constitutive laws relate: the evolution of the constitutive effective stress with imposed solid matrix deformation, the degree of saturation with suction stress, and the relative flow vector with intrinsic pressure for the water and air phases. Based on the FORTRAN language, a Finite Element Method program was coded, with a material subroutine named POROSTONE for the argillaceous shale elasto-plastic model, and then a soft argillaceous shale tunnel was simulated. At last, a compared analysis was derived with the data in-situ. Some results are revealed as follows: the porous elasto-plastic model works well and are in good agreement with the measured data in-situ; the deformation velocity is fast during the prophase of the tunnel excavating, compared with the later, but the steady time is long; some assistant measures, especially the lock-foot anchor should be set to enhance the steady state due

Abstract: The fire retardants were used in flexible polyurethane foam (PUF) to get fire retardant PUF, whose kinetic parameters activation energies (E) were calculated by Ozawa integral method and the Kissinger differential method. The results show that the correlation coefficient (R) is above 0.95, which shows good reliability of the two methods for solving E. E for the fire retardant foam is decreased by 80 kJ•mol-1, which shows that the fire retardant can catalyze decomposition and carbonization of flexible PUF.