Advanced Materials Research Vols. 282-283

Abstract: Localized flaws such as corrosions in petroleum pipelines often cause fragility, impairing integrity and shortening service lifetime of the structures. There has been much interest recently in monitoring the integrity of the pipe structures. Ultrasonic guided waves provide a highly efficient technique for rapid pipe inspection because they can be made to propagate significant distances in pitch-catch configurations. Crosshole tomographic geometry is formed in such pitch-catch configurations when transmits and receivers are respectively laid along two parallel circumferential belts around the pipe. Considering the pipe as an unwrapped plate, we investigate the adapation of the tomographic reconstruction in seismology to the guided wave inspection of a pipe. Various effects such as transducer arrangement, mesh precision, sampling interval and iterative algorithm on tomographic reconstruction are analyzed. The results provide a theoretical basis for quantitative detection of pipeline flaw using guided wave tomography.

Abstract: Nowadays, with the rapid development of technology and the rapid popularization of Internet applications, many Chinese businesses are attracted by huge profits and market space of e-commerce, beginning to join the area of e-commerce. How to keep effective customer, attract more members of the e-commerce website and expand the market effectively, is the problem that all the managers most concerned about. Through studying and comparing common customer segmentation models, this article is proposing a integrated model that combines the techniques of generalized association rules and decision tree. This model is used for customer segmentation for e-commerce websites. It can help managers understand customers, develop markets, and support decision-making.

Abstract: Basing on the experiment and design data of the two solar desalination systems by bubbling humidification, the GOR (gain output ratio), R (electric power consumption of unit freshwater output) and C (freshwater production cost) are calculated and compared. It's obtained when the humidifying temperature is increased, GOR is increased, while R and C are decreased; if the humidifying temperature increased by 10°C, C would be reduced by half. The electric power consumptions of the systems mainly depend on the blower’s consumption, while the electric power consumed by seawater pumps is little. It is the guide and basis for reducing the freshwater production cost and further improving the rationality of process.

Abstract: Signal enhancement of ultrasonic guided waves is studied using time reversal technique. The defect in pipe is detected by activating single mode guided waves L(0,2) at the center frequency of 70 kHz. Time-reversal technique is used to further enhance the defect detection capability. A method to identify the defect is described on a finite element model. Numerical results show that the time reversal technique has the ability to evidently enhance the amplitude of damage reflected wave and improve the detection efficiency of defect.

Abstract: The synthesis of NdFeO₃ perovskites in a reverse microemulsion and its photocatalytic property for visible light degradation reaction of methylene blue were investigated, respectively. When the irradiation time prolonged from o to 90 minutes, the degradation rate for methylene blue could achieve 60%. XRD pattern shows that a well-crystallized perovskite structure is observed for the NdFeO₃ sampled prepared. The TEM characterization result indicates that the dimension of NdFeO₃ nanopowders is in the range of 35~45 nm, which is consistent with the calculation result using the Scherrer equation.

Abstract: Nano-titanium dioxide (TiO₂) was synthesized by sol-gel method and was used as photocatalyst for photocatalytic oxidation desulfurization of fuel oil. Et₃NHCl·FeCl₃ was synthesized as low-viscosity ionic liquid (IL) and used as efficient extractant and oxygen in air was used as oxidant. Nano-TiO₂ was analysis by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The factors influencing the desulfurization rate of model oil such as oil ratio, the amount of titanium dioxide, the air pass into the volume and photocatalytic time. The results show that the desulfurization rate could reach 98.5% in 3h under below conditions: TiO₂ amount was 0.1g/100mL, air flow was 500 ml / min and V(IL):V(oil)=1:1.

Abstract: In this paper, basing on fundamental equations of double films and mass transfer theory, the theoretical expression of air humidification flux is deduced; according to the expression, the major factors influence the humidification flux on single hole bubbling are water temperature, air temperature, air flow rate, partial pressure of initial vapour in air, diameter of bubble, etc. High-speed camera technology is used to photograph the experiment of single hole bubbling humidifyication; according to the results of experimental measurement and photographing, the humidification flux is calculated under different diameters of sieve holes, water levels and air flow rates, and found it's related to the bubble diameter, it provides an effect method to calculate humidification flux by visual experimental data.

Abstract: The control of chaotic synchronization is the kernel technology in chaos-based secure communication. Those control methods have to transmitting control signal which increase the security risks of the communication system. Attacker can reconstruct the chaotic system or estimate parameters by using the information of the chaotic system. In this paper we propose a hybrid Super Chen chaotic synchronization scheme control which contains both continuous chaotic system with oscillating parameters and discrete chaotic system. If oscillating parameters satisfyingwhen , we proved that two systems can get synchronized without control signal transmitting.

Abstract: Most properties of Super Chen’s chaotic system satisfy with the requirements of secure communication and cryptography. Implusive stabilzation for control and synchronization of Super Chen’s chaotic systems can be applied in secure communication. Super Chen’s Chaotic synchronization control can be the kernel technology in chaos-based secure commu-nication. In this paper we propose a hybrid Super Chen chaotic synchronization scheme control which contains both continuous chaotic system with a sort of oscillating parameters and discrete chaotic system. If oscillating parameters approach to 0, we proved that two systems can get synchronized without control signal transmitting.

Abstract: Aldehyde dehydrogenases (ALDHs) represent a protein superfamily of NAD(P)⁺-dependent enzymes that oxidize a wide range of endogenous and exogenous aliphatic and aromatic aldehydes. The conserved sequence of aldehyde dehydrogenase gene (ALDH) was amplified from Fraxinus velutina by RT-PCR. The results demonstrated that the conserved sequence was 718 bp in length, which was deduced coding 229 amino acids. Homology analysis showed that the deduced amino acids sequence of FvALDH shared 56.9%%-73% identity with aldehyde dehydrogenase from other plants. We examined the expression pattern of the FvALDH gene in leaf treated with NaCl stress for defferent time using semi-quantitative RT-PCR. The results showed that the expression of FvALDH was increased after the first decreased, and then in a steady state with the time went on.