Preparation and characterization of DLC/SiO2/Al2O3 nanofiltration membrane

High quality ceramic thin films were fabricated by thin film deposition process in semiconductor field in order to fabricate high performance carbon/SiO ₂ /Al ₂ O₃ membrane. α-Al ₂ O ₃ substrate was used as a supporting material. A severe thermal stress and rough surface for active ceramic top layer such as zeolite were observed. To overcome thermal stress, intermediate layer of SiO₂ and diamond-like carbon (DLC) thin film were used. SiO ₂ and DLC thin films on porous alumina support were deposited using plasma-enhanced chemical vapour deposition (PECVD). Homogeneous and smooth surfaces and interfaces of DLC/SiO ₂ /Al ₂ O ₃ membrane were observed by FESEM. The phases of DLC and SiO ₂ thin films were identified by X-ray diffraction pattern. Gas permeabilities of the nanofiltration membrane with DLC/SiO ₂ /Al ₂ O ₃ were observed at various annealing temperatures. Mixed gas permeability of the membrane with 1 μm-thick SiO₂ and 2 μm-thick DLC thin film annealed at 200 °C was ～18 ccm at 1018 mb back pressure.     

Microstructure evolution and mechanical properties of Ti-B-N coatings deposited by plasma-enhanced chemical vapor deposition

Ternary Ti-B-N coatings were synthesized on AISI 304 and Si wafer by plasma-enhanced chemical vapor deposition (PECVD) technique using a gaseous mixture of TiCl4,BCl3,H2,N2,and Ar.By virtue of X-ray diffraction analysis,X-ray photoelectron spectroscopy,scanning electron microscope,and high-resolution transmission electron microscope,the influences of B content on the microstructure and properties of Ti B N coatings were investigated systematically.The results indicated that the microstructure and mechanical properties of Ti-B-N coatings largely depend on the transformation from FCC-TiN phase to HCP-TiB2 phase.With increasing B content and decreasing N content in the coatings,the coating microstructure evolves gradually from FCC-TiN/a-BN to HCP-TiB2 /a-BN via FCC-TiN+HCP-TiB2/a-BN.The highest microhardness of about 34 GPa is achieved,which corresponds to the nanocomposite Ti-63%B-N (mole fraction) coating consisting of the HCP-TiB2 nano-crystallites and amorphous BN phase.The lowest friction-coefficient was observed for the nanocomposite Ti-41%B-N (mole fraction) coating consisting of the FCC-TiN nanocrystallites and amorphous BN phase     

Fast and Simple Motion Tracking Unit with Motion Estimation

Surveillance system using active tracking camera has no distance limitation of surveillance range compared to supersonic or sound sensors. However, complex motion tracking algorithm requires huge amount of computation, and it often requires expensive DSPs or embedded processors. This paper proposes a novel motion tracking unit based on different image for fast and simple motion tracking. It uses configuration factor to avoid noise and inaccuracy. It reduces the required computation significantly, so as to be implemented on Field Programmable Gate Array(FPGAs) instead of expensive Digital Signal Processing(DSPs). It also performs calculation for motion estimation in video compression, so it can be easily combined with surveillance system with video recording functionality based on video compression. The proposed motion tracking system implemented on Xilinx Vertex-4 FPGA can process 48 frames per second, and operating frequency of motion tracking unit is 100 MHz.     

Security Analysis and Improvement of Authentication Scheme Based on a One-way Hash Function and Diffie-Hellman Key Exchange Using Smart Card

A new authentication scheme based on a one-way hash function and Diffie-Hellman key exchange using smart card was proposed by Yoon et al.in 2005.They claimed that the proposed protocol is against password guessing attack.In this paper,the author demonstrate that Yoon's scheme is vulnerable to the off-line password guessing attack by using a stolen smart card and the DoS attack by computational load at the remote system.An improvement of Yoon's scheme to resist the above attacks is also proposed.     

THE EFFECTS OF THERMAL AND NONTHERMAL PROCESSING METHODS ON APPLE CIDER QUALITY AND CONSUMER ACCEPTABILITY

Due to increased concern about the safety of fruit, vegetable and juice products, the FDA has mandated that these must undergo a 5‐log reduction in pathogens. The development of various processing methods for juice products has caused the need to determine the effects of these methods on said products. The effect of thermal pasteurization, UV irradiation and ozone treatment on apple cider quality and consumer acceptability was studied over 21 days. Thermally pasteurized samples were different in color and less preferred in all areas of consumer acceptability. UV‐irradiated samples were lower in soluble solids for the first 7 days and showed no significant difference in consumer acceptability. Ozone‐treated cider had greater sedimentation, lower sucrose content and a decrease in soluble solids by day 21. UV irradiation allows for a more cost‐effective method to produce safe apple cider with minimal quality and consumer acceptability differences.     

Improved lateral force calibration based on the angle conversion factor in atomic force microscopy

A novel calibration method is proposed for determining lateral forces in atomic force microscopy (AFM), by introducing an angle conversion factor, which is defined as the ratio of the twist angle of a cantilever to the corresponding lateral signal. This factor greatly simplifies the calibration procedures. Once the angle conversion factor is determined in AFM, the lateral force calibration factors of any rectangular cantilever can be obtained by simple computation without further experiments. To determine the angle conversion factor, this study focuses on the determination of the twist angle of a cantilever during lateral force calibration in AFM. Since the twist angle of a cantilever cannot be directly measured in AFM, the angles are obtained by means of the moment balance equations between a rectangular AFM cantilever and a simple commercially available step grating. To eliminate the effect of the adhesive force, the gradients of the lateral signals and the twist angles as a function of normal force are used in calculating the angle conversion factor. To verify reliability and reproducibility of the method, two step gratings with different heights and two different rectangular cantilevers were used in lateral force calibration in AFM. The results showed good agreement, to within 10%. This method was validated by comparing the coefficient of friction of mica so determined with values in the literature.     

Dynamic behaviour of domains during poling by acoustic emission measurements in La-modified PbTiO3 ferroelectric ceramics

In order to study the dynamic behaviour of domains during poling, the acoustic emission (AE) characteristics of two La-modified PbTiO3 ferroelectric ceramics in which 90° and 180° domains were respectively dominant have been investigated. One sample was a 15 mol% La-doped ceramic with a high tetragonality ratio (c/a=1.021) and the other was a 24 mol% La-doped ceramic where the tetragonality ratio was close to unity (c/a=1.007). The acoustic emission behaviour of the former sample consisted of both burst as well as continuous emission, with the latter sample mainly showing continuous emission. Energy distributions made it possible to distinguish between the AE signals resulting from 90° and 180° domain switching. From the observed results, it was confirmed that most of the AE occurred due to 90° domain switching. By introducing an alternative switching behaviour for the 90° domains, the behaviour of the AE generation during poling could be explained.     

Advances in J‐integral estimation of circumferentially surface cracked pipes

This paper describes enhanced J‐integral estimation schemes for pipes with circumferential semi‐elliptical cracks subjected to tensile loading, global bending and internal pressure. These schemes are given in two different forms to cover the wide ranges of geometries and material parameters; the modified GE/EPRI method and the modified reference stress method. In the former method, new plastic influence functions for fully plastic J‐integral estimation are developed based on extensive three‐dimensional finite element calculations. In the latter method, new optimized reference loads are suggested and utilized to predict the J values. To verify the feasibility of these two schemes, J‐integral values obtained from further detailed FE analyses are compared to those from the proposed schemes. Because the estimated J‐integrals agree fairly well with the detailed FE analysis results, the new solutions can be applied for accurate structural integrity assessment of different size pipes with a circumferential surface crack.