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The effects of Zr addition on the microstructural evolution and mechanical properties of FeCrAl alloys were investigated. Fine Fe2Zr particles with their sizes ranging from 0.5 to 1.2 μm were observed when the alloying element Zr was introduced in FeCrAl alloy. The addition of Zr led to the formation of Fe2Zr particles either within the grains or on the grain boundaries, and this was found to enhance the strength of the FeCrAl alloys. Moreover, the Fe2Zr particles stabilized the microstructures by promoting recrystallization nucleation and retarding grain growth. The critical size of the Fe2Zr particles for stimulating recrystallization nucleation and the activation energy of grain boundary migration during recrystallization were determined. The effects of Fe2Zr particles on particle-stimulated nucleation behavior and recrystallization grain growth dynamics are discussed.

The principle and control method of PCS circuit based on DSP2812 are introduced.The unified model of equations and simulation is built based on the topology of the circuit.The real-time simulation and directly generation of the control code is implemented using Embedded Coder of MATLAB toolbox.The integrated control and simulation design of control algorithm and dynamic process of PCS are implemented.

This article presents a double closed loop control system for three-phase voltage sourcePWM rectifier based on a real-time workshop(RTW), introduces the debugging method of 64-bitRTW platform. Then the simulation model is converted into the real-time code, and downloaded tothe platform controlled of DSP TMS320F2812 to verify the feasibility. The experimental resultsagrees the simulation results. This method greatly reduces the project development cycle and cost.

AbstractThe establishment of standardised methods for monitoring the oriental fruit moth Grapholitha molesta(Busck) (Lepidoptera: Tortricidae) requires the identification of factors that significantly affect trap catch efficacy. We examined the effects of trap height, trap location, and inter-trap spacing on trap catches in a conventional peach orchard. Traps were placed at heights of up to 3.0 m above the ground and sets of nine traps were positioned in grids with inter-trap distances of 10–50 m to determine the optimum trap height, location, and spacing. Traps were checked daily over 10 days for males during four periods corresponding to peak moth flight. Moth catches were higher when traps were placed toward the tops (2.5 m) and outside the canopy (3.0 m). Moth catches in traps located upwind and outside tended to be higher than in the central trap for all inter-trap distances. When inter-trap distances were shorter than 30 m, interference between traps occurred. Our results provide an efficient trap distribution for monitoring G. molestain peach orchards.

The nonlinear ionization process was discussed in detail induced by femtosecond pulse in Lithum Niobate (LN) crystal. The MPI provides “seed” electrons for avalanche ionization process, and avalanche becomes significant when the density of electron created by MPI over 1020 cm-3. Recombination process leads to an obvious drop of electron density and then a dynamic equilibrium is achieved between the generation of electron and the recombination process, and the density is dependent on the incoming field.

In this paper, the background of ultrasonic vibration internal grinding (UIG) technology was described; the main parameters of the UIG technology were summarized. The recent development of the UIG mechanism, system and ultrasonic vibration internal honing technology was overviewed. The development trend and future prospect of the UIG technology were proposed based on above analysis.

With the development of manufacturing automation and intelligent increasing speed, the construction in plant management information has been important tasks to promote business innovation ability, improve competitiveness and manufacturing execution. In this paper, UML (Unified Modeling Language) and object-oriented modeling technology were applied to model the static structure and dynamic behavior of the plant management information from requirement analysis to system implementation, including functional requirement model, static structural model, asset management time sequence chart, system physical model and so on. The visualized system analysis method and technology better planned the system design and improved the efficiency of the system development. It will play a guiding role in the object-oriented software development.

Background & Aims: Phospholipase activity may play a role in the pathogenicity of Helicobacter pylori. Furthermore, some drugs that are effective against H. pylori infection are phospholipase inhibitors. Scrutiny of the H. pylori 26695 genome sequence revealed the presence of a putative protein with homology to Esherichia coli outer membrane phospholipase A (PldA). The aim of this study was to investigate the role of this putative PldA in the pathogenicity of H. pylori.Methods: An isogenic pldA mutant was constructed and analyzed for in vitro phospholipase A"2 and hemolytic activity. Adherence of the mutant to human gastric adenocarcinoma cells and the ability to colonize mice were also investigated. Results: The pldA mutant showed a marked reduction in phospholipase A"2 and hemolytic activity compared with the wild-type strain. The mutant was unable to colonize mice at 2 and 8 weeks, but it did induce a significant immune response. In contrast, the ability of the mutant to adhere to human gastric adenocarcinoma cells was unaffected. Conclusions: The results suggest a role for PldA in colonization of the gastric mucosa and possibly tissue damage after colonization. GASTROENTEROLOGY 1999;117:1098-1104

Possible cadmium (Cd) exposure-associated changes in urinary levels of low-molecular-weight proteins mere studied in nonsmoking and nondrinking female members of the general Japanese population (378 subjects with no known occupational heavy metal exposure) who lived at 19 study sites (all without any known environmental heavy metal pollution) in 13 prefectures throughout Japan. The external Cd dose was evaluated in terms of daily Cd intake via food (Cd-F), whereas Cd levels in blood (Cd-B) and urine (Cd-U) were taken as internal dose indicators. When the subjects were classified according to Cd-F into three groups with "low" (20.4 μg/day as a geometric mean of 97 women), "middle" (35.0 μg/day, 120 women) and "high" (67.0 μg/day, 66 women) exposure, both Cd-B and Cd-U increased in parallel with the changes in Cd-F. However, there were no dose-dependent changes in β2-microglobulin or retinol-binding protein levels in urine. α1-Microglobulin levels appeared to increase, but the distribution of the cases above the two cutoff levels of 9.6 and 15.8 μg/mg creatinine among the three Cd-F groups did not show any bias. Overall, it was concluded that there was no apparent Cd exposure-associated elevation in urinary low-molecular-weight protein levels in the study population.

This survey was conducted in Seoul, Pusan, Chunan, and Haman in Korea to clarify cadmium and lead burden in the general Korean populations in terms of dietary intake of cadmium and lead and the concentrations of the two metals in blood. People who participated in the study were 141 healthy nonsmoking women aged 21-56 years. Determination of cadmium and lead in 24-hr food duplicates and blood samples was carried out by graphite furnace atomic absorption spectrophotometry. The geometric means for the four sites in combination were 21.2 µg/day for dietary cadmium, 20.5 µg/day for dietary lead, 1.27 ng/ml for blood cadmium, and 44.3 ng/ml for blood lead. Cadmium intake from boiled rice accounted for 23% of total daily cadmium intake. The counterpart value for lead intake from boiled rice was 12%. Blood cadmium levels and dietary cadmium intake were lower and blood lead level and dietary lead intake were higher in Korean women than in Japanese women. The values for dietary cadmium are similar to, and the values for dietary lead are somewhat lower than, the levels reported from Europe and the United States. Dietary intake was the main source of cadmium exposure, whereas lead exposure was from both ambient air and foods in the Korean population.Copyright 1995, 1999 Academic Press

The length of point rainfall records necessary to characterise the long-term cumulative distributions is studied and some conclusions drawn. Evidence of a periodical component in annual rain statistics, correlated with sun activity, is presented.

A new architecture is presented for a multibit oversampled σ-Δ A/D convenor. A novel feedback arrangement is employed to reduce the sensitivity of the overall resolution to the nonlnearity of the multibit DAC. Simulations confirm the improved performance achieved by the proposed structure.