Advanced Materials Research Vols. 317-319

Abstract: In this paper, using Bresenham line algorithm and uniform acceleration , uniform deceleration control algorithm, Combining compensation control about Z-axis motion on cylindrical surface, the author has writed a complete linear motion control program by integer addition, subtraction, logic operations. The program applies to specific numerical marking machine, you can part the plane, cylindrical surface marking.

Abstract: Instruction compression technique overcomes the drawbacks of traditional VLIW architectures with low density in the instruction cache. However, the separated long instruction word was arranged into two cache line. It comes to be a bottleneck problem for VLIW architecture processor performance because these split long instruction word can not be fetched and issued simultaneously. A novel two-level instruction issue window mechanism is proposed in this paper. It solves the instruction fetch and issue problem in separating instruction words. It provides more effective and continuous instruction flow, and stores one iteration of the loop body to support software pipeline technique, which improves VLIW DSP processor performance effectively. Proposed machanism was synthesized to evaluate its overall costs, and the performance speedup result for DSP/IMG library bencharks using the cycle accurate simulator are presented.

Abstract: In this paper, a reformative scatter difference discriminant criterion (SDDC) with fuzzy set theory is studied. The scatter difference between between-class and within-class as discriminant criterion is effective to overcome the singularity problem of the within-class scatter matrix due to small sample size problem occurred in classical Fisher discriminant analysis. However, the conventional SDDC assumes the same level of relevance of each sample to the corresponding class. So, a fuzzy maximum scatter difference analysis (FMSDA) algorithm is proposed, in which the fuzzy k-nearest neighbor (FKNN) is implemented to achieve the distribution information of original samples, and this information is utilized to redefine corresponding scatter matrices which are different to the conventional SDDC and effective to extract discriminative features from overlapping (outlier) samples. Experiments conducted on FERET face databases demonstrate the effectiveness of the proposed method.

Abstract: The nominal yield ratio, true yield ratio and static toughness of five materials X80, X65, X60, X46 and Q235 have been tested in this paper. The yield ratio of pipeline steel is rising with the increase of strength level, which is inevitable for the high strength pipeline steel. Based on the analysis of static toughness calculated by the true stress-strain curve, it is indicated that the deformation energy of X80 pipeline steel after the necking process in the course of static tension is high comparatively, and the deformation energy of X80 pipeline steel before the necking process is closed to that of the pipeline steel X46 and X60 with low yield ratio. It is showed that the increase of yield ratio did not lead to the decline of the static toughness.

Abstract: The effect of chemical constitution, casting technique and heat treatment parameters on microstructure, properties and wearing resistance of the bimetal composite were primarily researched by SEM, EDAX, TEM etc.. The results showed that the higher impact toughness at bimetal combination region than corresponding part of the high carbon steel was obtained. The impact toughness was 23J/cm2 and the hardness of resistant surface was HRC59. The high carbon steel region initiated the impact fracture, however its abrasion resistance was substantially improved over double than Mn13.

Abstract: Considering the condition that the longevity of hammerhead of single roll crusher is short, both technologies of welding stick with high chromium cast iron and prevent-split board were used to overlay-weld the hammerhead unitarily. The results are found that the longevity of the hammerhead improved is 8 times longer than that before the experiment.

Abstract: Prediction and control of the microstructure to improve product performance are very important for the industry practice. In this study, microstructure evolutions of 30Cr2Ni4MoV steel under different conditions were simulated by changing the process parameters using the Deform 3D software. Effects of the forming process parameters on the microstructure were revealed: (1) the higher the temperature and the lower the strain rate, the smaller the strain are needed for the dynamic recrystallization; (2) when strain is enough, the higher the strain rate, the easier the uniform and small grain size can be obtained; (3) under a certain strain rate, the grain size increases as the deformation temperature increases. The microstructure of metal can be predicted and controlled according to the effects of hot forming process parameters on the microstructure evolution.

Abstract: The removable partial denture framework is very complex in shape with many curved surfaces, which is a very important assistant tool in prosthodontics. Generally, frameworks are fabricated by single piece basing on mould by traditional cast technology, which has many shortages of multiple steps, time cost and defects such as sand adheres, inner holes, cracks and segregation etc. As a novel method, selective laser melting (SLM) rapid prototyping technology has the advantages of short manufacturing cycle, high precision and flexibility, simple fabrication arts, which can be used to replace the conventional cast technology in the areas of prosthodontics. A SLM system was designed and developed by ourselves, which is consisted of an Yb-fiber laser, an optical scanner, a powder coating device, a gas purification system and a control system, the process parameters were investigated systematically and optimized, finally fabricated removable partial denture frameworks with stainless steel and titanium materials successfully by using the SLM system under optimized parameters. The tests showed that the frameworks have an average dimension precision of ±0.172mm. The wearing experiments on the plaster mouth molds demonstrated the removable partial denture frameworks fabricated by SLM can be fully applied to clinic after some post- processing procedures.

Abstract: In this research, TP304 was treated by shot blasting under the pressure of 0.65MPa. The stainless steel shots used in the shot blasting experiment were in different sizes, separately with diameter 0.6mm and 1.2mm. To investigate the effect of shot blasting on the oxidation resistance behavior, steam oxidation experiments have been conducted to both original and shot blasting treating TP304s in 650°C and 25MPa. Then oxidation kinetics curve of each sample was measured by discontinuous weight method, morphology of oxide film was observed through SEM(scanning electron microscope), the component of the oxidation was measured by XRD(X-ray Diffraction), and the variation of Cr content in the oxide film was analyzed by EDS(energy-dispersive X-ray spectroscopy). According to the results, Oxidation kinetics curve in high temperature and pressure, expressed in original and shot blasting treating TP304s, both follow the principle of quasi-parabola and shot blasting can largely enhance TP304’s steam oxidation resistance in high temperature and pressure.

Abstract: The aim of this study was to manufacture the ternary solid dispersions composed of nifedipine, Eudragit^® E and adsorbent. Dissolution enhancement of nifedipine was also investigated. The inert solid carriers were added in the mixtures of nifedipine and Eudragit^® E at varying ratios. The physicochemical properties of ternary systems, compared to physical mixtures, were analyzed using powder x-ray diffraction (PXRD) and differential scanning calorimetry (DSC). The dissolution of nifedipine from ternary systems was compared to the drug alone. The influence of drug:polymer: adsorbent ratio and type of adsorbent on the dissolution rate of the drug was also evaluated. The PXRD and DSC results of the systems with high amount of polymer showed that the drug was present in an amorphous form. On the other hand, the diffraction patterns and DSC thermograms of the physical mixtures revealed that to some extent the drug was present in a crystalline form. The results from this study demonstrated that an improvement in dissolution rate of nifedipine with Eudragit^® E and adsorbents was obtained.