Advanced Materials Research Vols. 287-290

Abstract: Bentonite has been regarded as buffer material for high-level radioactive waste (HLW) disposal all over the world, plenty of decay heat released from HLW is conducted through butter material, therefore, thermal conduction of compacted bentonite is very important. This study presents compacted GMZ Na-bentonite(with 8.9% water content, 1.8 g/cm³ compacting density) temperature and relative humidity change pattern with time and position variation taking intermittent warming method and using thermal conduction equipment, it is designed according to the conceptual model of HLW geological disposal repository. The results show that the temperature achieve a balance quickly, the temperature of compacted bentonite block which the distance is 2 cm to heat source reaches the first about 55°C balance stage after about 40 hours, radial temperature gradient (G_T) increases with the temperature rising, average of G_T during the first stage is 0.85°C/cm, average of G_T during the second balance stage about 82°C is 1.57°C/cm; Affected by temperature, relative humidity increase rapidly at the beginning with the temperature rising, when the temperature reaches equilibrium, the relative humidity decreases slowly, the higher temperature of the compacted bentonite block is, the lower relative humidity is, the radial gradient of relative humidity (G_HR) increase with heating time, average of G_HR during the first stage about 55 °C is 1.32%/cm, average of G_HR during the second stage about 82°C is 1.89 %/cm.

Abstract: With the development of industry, water pollution is increasingly severe. The research and development of oil-absorbing materials plays an important role in solving the ecological environment protection. Various oil-absorbing materials are introduced. Then, the new oil-absorbing materials are introduced mainly, including classification, production methods, oil-absorbing mechanism and properties. The limitations of the new oil-absorbing materials are pointed. And the development direction of oil-absorbing materials should be toward the high efficiency, low-cost, environmentally friendly and biodegradable.

Abstract: Self-propagating High-temperature Synthesis (SHS) was used to prepare complex oxide La_0.7Sr_0.3MnO₃, which is used as the cathode in solid oxide fuel cells (SOFCs). Experiments show that La_0.7Sr_0.3MnO₃ can be prepared via SHS under moderate conditions from a mixture of La₂O₃-SrO₂-Mn-NaClO₄-KMnO₄，using NaClO₄-KMnO₄ as dual oxidants. The proper addition of the second phase oxidant KMnO₄ makes the combustion wave movement stable. The product powders have an average particle size of 1-2μm and the particles are small aggregate. Pellets were sintered at 900 °C, 30 MPa for 10 min by spark plasma sinter (SPS). The electrical conductivity of sintered sample was 170 S•cm^-1 at 1000 °C in air.

Abstract: The mechanical and tribological behaviors of the carbon/carbon (C/C) composites were evaluated by three-point bending and sliding wear tests. The effect of carbon fiber content on their mechanical behavior was also investigated. To produce the C/C composites, the precursor was introduced to the preforms by impregnating with phenolic solution. The C/C preforms were densified by thermal gradient chemical vapor infiltration. Results indicated that, the C/C composites show excellent mechanical and tribological properties. A kind of high performance brake materials was obtained.

Abstract: In this article, we synthesized a porphyran-like complex composed of iron chloride and carbon nitride polymer (CNP) as a new photocatalyst with visible light response. Several chemical reactions were carried out to confirm it to be a complex, while FTIR, XRD, XRF were used to further prove its structure. According to the UV-Visible diffuse reflectance spectra, the absorption had been extended to visible light region. Photodegradation of methyl orange (MO) on this novel Fe-CNP complex confirmed it possesses high activity under visible light irradiation.

Abstract: Magnesium borate (Mg₂B₂O₅) whisker was successfully synthesized by high temperature flux method using Magnesium chloride, boric acid, sodium hydroxide and sodium chloride as raw materials.The as-prepared product was characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy(SEM), Transmission Electron Microscope (TEM) and X-Ray Photoelectron Spectrometry (XPS). The results showed that the as-prepared sample had triclinic structure and consisted of whisker-like particles with an average diameter about 1.25 μm and length up to 40μm. XPS results confirmed that the molar ratio of each atom agreed with the stoichiometric composition of Mg₂B₂O₅. The growth mechanism was briefly discussed.

Abstract: The novel bis(2, 4-dihydro-2H-3-(4-N-maleimido) phenyl-1, 3-benzoxazine)isopropane (BMIPBI) was synthesized from maleic anhydride, p-nitroaniline, formaldehyde and 2,2-bis(4-hydr -oxyphenyl)propane by a few steps reactions via the N-(4-nitrophenyl)maleimide(NPMI), N-(4-amin -ophenyl)maleimide(APMI),1,3,5-three(4-(maleimido)phenyl)-1,3,5-triazine(TMIPT)intermediate production. The chemical structures of BMIPBI were confirmed by ¹H-NMR, FT-IR and EA. The results show that the production was the target object BMIPBI. The synthesized condition had been studied too. The BMIPBI was a loosened yellow solid and the yield of product was 58.8%.

Abstract: Phase change material (PCM) can absorb or release a large quantity of latent heat when it changes phase from solid state to liquid state or vice versa, and has very important applications in thermal energy storage systems. One of the combination methods is incorporating PCM in porous building materials, which are suitable matrix materials for PCM. In this paper, two kinds of ceramsite manufactured from East Lake sludge and paraffin were selected to form phase change composites by using the vacuum impregnation method. Differential scanning calorimeter (DSC) analysis was used to evaluate the phase change behavior. The result showed that the peak temperature (TP) and latent heat of the melting process of the paraffin in ceramsite A and B was a little higher than that of the bulk paraffin.

Abstract: This paper introduces material nonlinear finite element method and the establishment of finite element equation and realizes accurate modeling and calculation of folding rudder using material nonlinear finite element method. According to calculation and analysis, it is shown that the stress in contact part is relatively large due to stress concentration and material enters plastic deformation area. The influence of material nonlinearity on deformation calculation cannot be neglected. In this paper, deformation calculation results well coincide with experimental results.

Abstract: Through experimental study on three HRB400 steel bar reinforced concrete columns subjected to low cyclic reversed loading, the failure patterns, hysteretic curves and skeleton curves were obtained. The influence of longitudinal high-strength reinforcement ratio upon the hysteretic characteristics, ductile behavior and ability of energy dissipation were analyzed. The results show that the main failure pattern was bending failure; and with the increscent of the longitudinal high-strength reinforcing steel bar ratio, the columns can endure larger seismic loads and displacement; the seismic performance of the whole reinforced concrete columns can be effectively improved by arranging reasonable high-strength steel bars.