Applied Mechanics and Materials Vols. 333-335

Abstract: An acid self-diverting agent compound by betaine type surfactant and quaternary ammonium salt type surfactant was synthesized and evaluated. Found that when the pH value was higher than 1, acid viscosity rose rapidly, and the pH value up to 3, acid viscosity reached its maximum value (300mPa s), and can effectively made the acid diverse.When the pH value was 6, the system completely gelouted, easy to flowback; When added the self-diverting additives, acid system had better temperature resistance; With the elevated of concentration of the self-diverting agent, the apparent viscosity of acid increased, when the concentration of the self-diverting agent was more than 5%, the acid apparent viscosity increased little, gradually stabilized, but all above 300mPas, meet the industry standard requirements.

Abstract: A novel method of preparing CNT/sodium silicate composite film is put forward. By grinding and mechanical ball milling to get a homogeneous mixture, solidifying to form composite film and then exposing the CNTs on the surface of the film with their roots still in the sodium silicate by selective etching, the composite film was fabricated. Thanks to the wettability and adhesion between CNTs and sodium silicate the mechanical property of the film is improved. And the surface morphology of it is well-distributed and controllable. Such composite film is suitable to be applied in electrochemical sensor and field emission cathode.

Abstract: The nanostructure of α phase polyoctylfluorene thin film was characterized using normal X-ray diffraction, one-dimensional out-of-plane grazing incidence X-ray diffraction and two-dimensional grazing incidence X-ray diffraction with lab diffractometer and synchrotron diffractometer. The results show that using grazing incidence X-ray diffraction the weak diffraction signal of thin film can be observed after the elimination of background signals. Incorrect (h10) diffraction signals can be collected by lab diffractometer due to its low collimation and resolution, which can be overcome by using synchrotron diffractometer with high collimation and resolution that reveal the actual microstructure of polyoctylfluorene thin film.

Abstract: Considering the mechanical properties of X70 pipeline steel after repeated welding heat cycles, preheating and interpass temperature controlling are often adopted in the welding technology, which widely increase the welding construction time and lower the construction efficiency, thus improve the construction cost of pipelines. According to the present welding process of X70 pipeline steel, non-preheating welding technology was proposed in this paper. The experiment results show that the properties of the weld joint of X70 pipeline steel with non-preheating achieves the requirement of specified standard. Furthermore, this method simplifies the welding construction processes and improves the construction efficiency. Key Words:X70 Steel; Non-Preheating; Welding Technology

Abstract: Objective: Through the test of air conditioning cooling water circulation system and the electrical conductivity of iron corrosion velocity, find out the method of corrosion control measures; Methods: Rotating hanging plate method and conductivity meter and other cooling water test air conditioning system in different conductivity of metal iron corrosion rate; Conductivity results: Air-conditioning cooling water circulation system of more than 1900 μs/cm, metal corrosion rate less than 0.05mm/a, shall meet the relevant standards. Conclusion: Through the addition of corrosion inhibitor, scientific emission and control of circulating cooling water pH, conductivity decreased circulating water cooling, can reduce the corrosion of iron, to ensure the safe and stable operation of cooling water pipe and equipment.

Abstract: We perform a first-principles simulation to research the electronic and optical properties of wurtzite Zn_1-xCo_xO. The simulations are based on the Perdew-Burke-Ernzerhof form of generalized gradient approximation within the density functional theory. Calculations are carried out in different concentrations. With increasing Co concentration, the band gap of Zn_1-xCo_xO decreases due to the shift of valence band. Besides, it is shown that the insertion of Co atom leads to redshift of the optical absorption edge. Meanwhile, the optical constants of pure ZnO and ZnCoO alloys such as loss function, refractive index and reflectivity, are discussed.

Abstract: Nanometer sized Cu₂O is synthesised by nucleation crystallization separation and redox methods, with NaBH₄ as reducing agent. It takes several researching methods, such as XRD,SEM,EDS and UV-vis, etc, to study the structure, composition and spectral features of the product. The results show that, comparing with traditional methods, the Cu₂O particles produced by nucleation crystallization separation and redox methods have following features: similar appearances, small particle size, and narrow distribution, etc. The photocatalytic experiment shows that, this kind of Cu₂O has excellent photocatalytic activity over four nitrophenol.

Abstract: A new hydrocyclone and gas-flotation device was designed and tested for the treatment of the wash water containing the flocs. The device separates particles and removes flocs simultaneously. The gas-generator equipment can produce a large number of micro-bubbles, and the bubbles adhere to the impure flocs particles. This makes the density of the bubble-floc less than that of water, and their buoyancy enables particle separation and removal of suspended flocs. To achieve a high efficiency of flocs removal and particle separation, some of the factors that influence the separation efficiency (such as the gas-liquid pressure difference, gas-liquid ratio, underflow split ratio, water pressure, inlet flow rate, and the contact time of the gas and particles, bubble size, and number of bubbles) were investigated. The results showed that there is an optimum combination of multi-dimensional parameters; good particle separation and a high efficiency of flocs removal were achieved.

Abstract: Synthesis multilayered cage-like nanozinc oxide by hydrothermal method. The structure, composition and morphology of the composite precursor and the calcination were studied by means such as XRD, SEM, EDS and TG, etc, and the formation mechanism was preliminarily discussed. The result shows, the molar ratio of C₆H₁₂O₆/Zn²⁺ significantly affects the appearance and regularity of the cage structure and the thickness of the cage wall. The cage wall has porous structure feature, and might has unique photocatalytic property.

Abstract: The stability of tunnel surrounding rock is a key scientific issue in the design and construction of the tunnel engineering. Taking the load pattern of incremental form, the distribution law of stress and displacement field of the Osaka mountain tunnel after excavation was calculated based on the D-P yield criterion; Basing on the comprehensive heat and mass transfer theory, the temperature field in the surrounding rock was calculated and the variation of stress and displacement field after the surrounding rock experiencing the free-thaw cycles. All of the results can provide some references for the design and safe construction of the tunnel engineering under the action of freeze-thaw environment in cold regions.