Advanced Materials Research Vols. 616-618

Abstract: In this research, Ag/C catalysts was respectively prepared by application of the polymeric complex protection for Ag(I) in different content of Ag. According to the characterizations by X-ray diffraction and scanning electron microscope, it was proved that the particle size of Ag , which was obtained by application of the polymeric complex protection for Ag(I), was related to the mass ratio of PVP and silver nitrate, the concentration of silver nitrate and sodium borohydride. Simultaneously the electrocatalytic activity of Ag/C catalysts is discussed through the polarization curves.

Abstract: This paper presents the results of the reaction between metallic iron mesh rolls and NO in the presence of CO₂/O₂ at different temperatures. All experiments were carried out in a ceramic tube controlled by the temperature programmed electrical furnace. About 99% NO reduction was achieved when temperature was above 700°C in the absence of CO₂/O₂. Results showed that CO₂ in the flue gas had little effect on the NO reduction. NO reduction efficiencies were observed to exceed 95% for all CO₂ concentrations at above 700°C. The addition of O₂, however, caused a sudden drop by about 76% in NO reduction efficiency. Scanning electron microscope (SEM) results showed that the oxidation of iron in O₂ atmosphere led to a more continuous and impervious oxide layer than that in CO₂ atmosphere. Results using X-ray diffraction (XRD) to detect the iron samples after reactions revealed that FeO, Fe₃O₄, Fe and Fe₂O₃ were formed in CO₂ atmosphere, but Fe₃O₄ and Fe₂O₃ were formed when O₂ was added.

Abstract: This paper provides a comprehensive overview of the R&D status and advances of the cleaning of hydrogen sulfide from coal gas streams using zinc-based sorbents including ZnO, ZnFe2O4, Zn2TiO4 and supported zinc-based sorbents. The characteristics of single oxides sorbents, complex zinc-base sorbents and supported zinc-based sorbents are compared, including the preparation processes,desulfurization behavior and desulfurization precision, etc. Supported zinc-based sorbents are regarded as prospective sorbents in industrial applications due to their better desulfuization precision and regeneration properties. Char supported zinc-based sorbents have good performance during desulfurization at medium temperatures.

Abstract: In this paper, AlN ceramics doped with additive Sm₂O₃ has been synthesized by HPHT method. Furthermore, we have studied the impact of Sm2O3 on sintering AlN ceramic. The results show that the relative density of AlN ceramics increased at first, but decreased later with increasing Sm₂O₃. Compared with pressureless sintering, the time required to complete sintering AlN ceramic was shorter, and the sintering temperature was lower. And the growth model of AlN ceramics was pointed out and the proper explanation of its related phenomena were given in detail.

Abstract: Mesoporous silica aerogels with a high surface area and narrow pore size distribution were prepared from tetraethylorthosilicate (TEOS) precursor at ambient pressure by using a water miscible ionic liquid (IL) [Hmim]Br as a template. The aerogels were characterized by scanning electron microscopy (SEM) and N2 gas adsorption-desorption isotherms (BET and BJH analyses), and the effect of the IL on gel structure was also studied. The results showed that IL plays an important role in regulating the nanostructure of the aerogels, in particular, pore sizes and their distribution. By increasing the IL/Si molar ratio from 4 to 7, the specific surface area of the resultant aerogel increased from 822.38 to 992.43 m2/g, while the pore volume decreased from 1.568 to 1.031 cm3/g. More importantly, the pore size distribution became narrower with minimum average pore radius centralized at 20 nm as the IL/Si molar ratio of 7. Compared with other IL templating methods previously reported, notable attributes of this method include gelation at a much wider range of the IL/Si molar ratios (up to 7) and the formation of homogeneous porous structure whose size can be up to meso-scale (2 nm - 50 nm).

Abstract: Based on the classical cast theory and modern hot continuous rolling theory, in order to improve further the thickness precision of casting and control quality, so the dynamic mathematical model of strip-cast Looper system was established, which is nonlinear, strong coupling and uncertainty. According to the actual data, the comparative complete transfer function of Looper system is calculated. And the QDRNN-PID control strategy is put forward to subtract the coupling effect of Looper system. The simulation results prove that this control strategy can obtain a better control effect of Looper system after decoupling.

Abstract: The Co_1-xNi_xCr₂O₄ (x=0.1, 0.2 and 0.3) solid solutions were successfully synthesized by low-temperature combustion synthesis method. The crystal structure and optical properties of the samples were investigated. The samples displayed single phase spinel structure with 30 nm in grain size. Infrared absorption peaks at about 525 and 630 cm-1 corresponded to the vibration of octahedron group ([CrO6] / [NiO6]) and tetrahedron group ([CoO4] / [NiO4]) respectively. Due to the electronic transition of 4A2(F) → 4T1(P) of Co²⁺, 4A2g → 4T2g of Cr³⁺, 3T1g(F) → 3T1g(P) and 3A2g(F) → 3T1g(F) of Ni²⁺, absorption peaks at about 578, 618 and 670 nm were observed in the visible region, making the color center be green. The degree of lightness, greenness and chroma increased, whereas the degree of blueness decreased, making the color of the samples transit from pale green to brilliant green as x value increased.

Abstract: Erbium doped ZrO₂ (ZrO₂:Er³⁺) nanocrystals are fabricated by a butadinol low thermal crystallization method.The emitting mechanism of Er3+ is researched. Er3+ level of the stark split were calculated with the crystals field theory, and the two levels of the spectral lines have been further recognition. It can be indicated that 980nm stimulates Er3+ upconverting. One process is continuous absorption of two 980nm photons. Another is electronic transfer to metastability level after absorbing 980 nm photons, then reuptake 980 nm photons.

Abstract: India is veritable emporium of medicinal and aromatic trees. It has been estimated those trees occurring in India are commonly useful. Adansonia Digitata AnD is useful for different purpose like in bio- medical, chemical industries etc. The study of elastic behaviour of a solid is very important in fundamental and technical research. Strength and stiffness assessment of Adansonia Digitata AnD fruit shell and dried fruit pulp was a crucial task in the rehabilitation of Adansonia Digitata And fruit structure and its mechanical property Unsatisfactory results given by traditional procedures, therefore we applied non-destructive technique NDT. Solid bodies are not absolutely rigid by the application of suitable forces. We used the composite piezoelectric oscillator technique to calculate elastic behaviour of Adansonia Digitata AnD fruit part (fruit shell and dried fruit pulp) by the frequency 123.4 KHz of quartz crystal. In the present study Ultrasonic Inspection is a very useful and versatile NDT method to calculate the Ultrasonic Longitudinal Velocity and elastic constant of Adansonia Digitata AnD fruit shell and dried fruit pulp in the longitudinal direction with ultrasonic frequency at room temperature 308 K. We have measured the resonant frequencies of the specimen’s fs. The specimen’s were collected from Mandu, Dhar Dist. (M.P.) India known as mandav ki imali. Characterization of the samples was made by scanning electron microscope (SEM) Model JEOL JSM5400.The resonant frequencies of the specimens were measured by Ultrasonic Interferometer (for solids) dual frequency Mittal Enterprises, New Delhi.

Abstract: With the enhancement of environmental awareness and the development of coking technology, large domestic coking plant With the enhancement of environmental awareness and the development of coking technology, large domestic coking plant With the enhancement of environmental awareness and the development of coking technology, large domestic coking plant will use CDQ technology to deal with Coke. So a great number of coke powder will be produced in coking enterprises every day. This paper use coke power, the waste of coking enterprises, as raw material to produce activated carbon with good adsorption property by chemical activation. The surface chemical composition and surface area of the activated carbon were investigated. The effects of activation conditions on the characteristics of the activation carbons were studied.As a result, activated carbon with an iodine adsorption capacity of 1020mg/g, a methylene blue adsorption capacity of 365 mg/g and a specific surface area of 1600 m2/g was obtained. These adsorption capacities were almost the same as ordinary activated carbon on the market.