Advanced Materials Research Vols. 183-185

Abstract: The sulfur-doped Y-junction carbon nanotubes (S-YCNTs) were prepared by chemical vapor deposition of carbon disulfide using Fe as catalyst. Sulfur can be incorporated into the nanotubes with an identifiable amount, forming sulfur-doped carbon nanotubes. The growth of asymmetrical Y-branches in the nanotubes may be related to the presence of sulfur from precursor. The structure and morphology of S-YCNTs can be controlled by processing parameters. The S-YCNTs were characterized by SEM, TEM, EDX, and XPS, respectively. The growth mechanism of S-YCNTs was discussed in terms of the role of sulfur from carbon feedstock.

Abstract: In this research, a kind of Ionic Soil Stabilizer (ISS for short) is used as great extension of Ministry of Water Resources of the People’s Republic of China. Based on the red clay of Hanyan district of Wuhan reinforced by Ionic Soil Stabilizer, the red clay soil is treated by different matches of ISS and water at first, then is tested in the Atterberg limits test, dirct shear test and surface tension test. The results show that the plastic index decreases, and the cohesion increases after mixing the ISS into the red clay. In addition, Once ISS is dissolved in water, it can reduce the surface tension of water, and with the concentration increasing, the surface tension decreased. Finally the mechanism how ISS reinforces the red clay is analyzed by the aspect of the structure of pair-electricity layer and the Zeta potential.

Abstract: The physicochemical properties of nickel laterite ore powder were investigated by XRD, SEM and TG/DSC characterization techniques. The mechanical properties including repose angle and friction angle were measured by powder performance tester and direct shear apparatus. The result of XRD showed that the main phases of nickel laterite ore powder were lizardite and quartz. The SEM indicated that the internal structure of nickel laterite ore powder was loose relatively, samdwich and granular structures were found in microstructure. The results of TG/DSC indicated that the crystal water was removed at 610°C, and cristallographic transformation of antigorite to forsterite was occurred at 820°C. Repose angle and friction angle were influenced intensively by moisture content. Repose angle increased with the increasing of moisture content, dynamic repose angle was less than that of static repose angle, the fluidity of nickel laterite ore powder could be improved by the decreasing of moisture content. Internal friction angle and wall friction angle decreased with the increasing of moisture content because water acted as the lubrication action in mineral powder materials and decreased the friction coefficient of mineral powder materials.

Abstract: In this paper, a master/slave telenanomanipulation control system with force feedback is established with the micro-positioner (Attocube) working in scanning electron microscope (SEM) as the slave side and the haptic device (Omega3) as the master side. An improved virtual coupling (IVC) algorithm is introduced based on nanoscale virtual coupling (NSVC) by adding a proportional- plus-integral (PI) velocity controller in the haptic interface. The stability and performance of the established system are discussed. This method leads to an explicit design procedure for virtual coupling networks which give greatest performance while guaranteeing stability both on moving carbon nanowires in SEM and measuring force at the point of device-human contact.

Abstract: To reveal the pressure-transfer characteristics of the granular materials in the Solid Granule Medium Forming process, the stainless steel balls with diameter of 1 mm were selected as medium to conduct the axial compression experiment. The particle compression process was simulated by discrete element method, and then the variation law of the microstructure was analyzed from the perspective of force chain. The results showed that: In the gradual compression process of granule medium, its force chains distribution changes from the initial circular shape to the elliptical shape. As the stress increases, the force chains get denser and denser. In addition, the lateral pressure coefficient changes in power law with the compressive stress and it tends to be constant when the internal force chains structure gets stable.

Abstract: A mobile robot with autonomous recognition and automatic clearing small advertisements on the ground is presented. It’s the service-oriented robot for cleaning of small advertisements. The robot body is designed according to the design requirements of clearing and the control strategies for tracing and recognition small advertisements are proposed. The key issue of the robot is the hardware design for moving clean assisted by vision system and corresponding recognition methods. The results show the feasibility of the hardware structure, circuit design and program algorithm.

Abstract: Ni coatings with different grain sizes and preferred orientations were produced by the control of current density during a direct current electrodepositing process. The effects of grain size reduction and preferred orientation on the oxidation behavior in air at 600°C and 960°C of Ni coatings were investigated respectively. An important and interesting result is that after oxidation at 600°C, the Ni coating obtained at lower current density has a better oxidation resistance, whereas after oxidation at 960°C, the Ni coating obtained at higher current density has a more compact scale and a better oxidation resistance. For the Ni coatings oxidation at 600°C, the oxidation behavior was mainly influenced by grain size, whereas in the case of the Ni coatings oxidation at 960°C, the oxidation behavior was only slightly influenced by grain size. The changes in oxidation behavior of Ni coatings at 960°C can be attributed to the different preferred orientation and the corresponding oxidation mechanism.

Abstract: The photodegradation of reactive green KE-4BD solution is investigated using N-doped titania (N-TiO₂) under visible light irradiation. N-TiO₂ is prepared using ammonia or urea as a nitrogen source and characterized by X-ray diffraction, Brunauer-Emmett-Teller methods, and UV-visible diffuse reflectance spectra. The effects of the initial dye concentration and pH on photocatalytic degradation are studied, and the direct correlation between pH, dye concentration, and the rate of degradation are determined. Experimental results show that aqueous solutions of KE-4BD degrade easily in weakly acidic conditions in the presence of N-doped TiO₂ (1 g/L) as a photocatalyst. The optimized dye concentration for photolysis is 150 mg/L. The complete degradation of KE-4BD could be achieved under visible light irradiation, and the dye molecules could be partly decomposed into inorganic substances.

Abstract: Surfactant-modified zeolites (SMZ) with different coverage types were prepared by loading the cetylpyridinium bromide (CPB) onto the surface of the natural zeolite collected from Jinyun County, Zhejiang Province, China. The adsorption behavior of Cr(VI) on SMZ was investigated. Natural zeolite and SMZ with CPB monolayer coverage were inefficient for the removal of Cr(VI) from aqueous solution. However, SMZ with CPB patchy bilayer or bilayer coverage was efficient in the removal of Cr(VI) and the Cr(VI) adsorption capacity of SMZ increased with its CPB loading. The Cr(VI) adsorption capacity of SMZ showed a maximum at pH 3-6 and decreased with increasing pH from 6 to 11. The presence of competing anions such as chloride, sulfate and bicarbonate ions reduced the Cr(VI) adsorption capacity of SMZ. The adsorption process was strongly dependent on ionic strength, indicating that anionic exchange and electrostatic interaction were the main mechanisms that govern the adsorption of Cr(VI) on SMZ.

Abstract: The feasibility of producing biodiesel from Xanthoceras sorbiflia Bunge seed oil was studied. Biodiesel was prepared from refined Xanthoceras sorbiflia Bunge seed oil using methanol and sodium hydroxide in an alkali-catalyzed transesterification process. The refining process consisting of alkali deacidifying was developed to produce biodiesel from crude Xanthoceras sorbiflia Bunge seed oil. The acid value of oil was reduced from the initial 1.28mg- KOH/g-oil to below 1.0 mg-KOH/g-oil in 1 h under the conditions of NaOH 18% , excess alkali quantity 0.2wt% of oil at 30°C. The yield of biodiesel developed by refined Xanthoceras sorbiflia Bunge seed oil was higher than 89% in 60 min using NaOH catalyst that amount approximately1wt.% compared to Xanthoceras sorbiflia Bunge seeds oil as catalyst and a molar ratio of methanol to oil 6:1 at 60°C.