Papers by Keyword: Growth

Abstract: Formation behavior of texture during high temperature compression of AZ80 is investigated on the specimens produced from the extruded bar and rolled plate. Special attention is paid on the formation of (0001) (compression plane) texture. Before deformation, (0001) is distributed frequently parallel to the compression plane in the specimen produced from the rolled plates, while (0001) is frequently normal to the compression plane in the specimen produced from the extruded bar. The deformation is performed at temperatures and strain rates ranging from 673K to 723K and 1.0×10^-4s^-1 to 5.0×10^-2s^-1, respectively. It is found that fiber textures are formed by the deformation and the main component of the texture varies depending on the deformation conditions. The sharpness of (0001) texture after deformation in the specimen produced from extruded bar is much weaker than that in the specimen produced from rolled plate. It is concluded that the growth of (0001) grains during deformation is the basic process for the (0001) texture evolution.

Abstract: In this paper, the influence of the BNx implanted buffer layer on growth and residue stress of c-BN films were mainly investigated. The experiment results showed that the introduce of BNx implanted buffer interlayer can increase the c-BN content in the films and reduce the residue stress obviously. When the nitrogen dose was 9.6×1017 N+/cm2, the residue stress of c-BN films reached the least value of 3.0GPa. AFM showed that the surface of the c-BN film on the BNx implanted buffer layer is low in roughness and small in grain size. XPS analysis results show an interfacial mixing in the buffer layer have an even N/B distribution. And the surface of buffer interlayer was mainly in BN phase, which is the main reason to improve the growth conditions and reduce the residue stress of c-BN films.

Abstract: The effect of color shading-nets (red net, blue net and silver net) and ordinary black net on plant growth and nutrient uptake of flowering Chinese cabbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee) were studied, with no net shading as the control. The results indicated that, compared with the control, red net covering increased plant height, leaf area and stem diameter of flowering Chinese cabbage. Red and blue nets covering enhanced the above ground fresh weight, while the silver and black nets covering decreased the above ground fresh weight. Shading net covering significantly improved the nitrogen (N) and potassium (K) content of flowering Chinese cabbage, while it had no significant effect on the phosphorus (P) content. Red and blue nets covering enhanced mineral nutrients uptake, while it was decreased under silver and black nets covering. Red and blue nets covering promoted plant growth and nutrients uptake of flowering Chinese cabbage and could be widely applied in leaf vegetable production.

Abstract: The mold-shell interface plays a very important role during the earliest stages of metal casting processes. Heat is extracted from the molten metal through this interface resulting in the growth of the shell. Small spatial variations in heat extraction can lead to shell morphological instability where certain regions of the solidification front grow preferentially over others. This may cause cracks in the shell which can greatly reduce the integrity of the final cast product. Mold coating at the mold-shell interface is one of the most important factors controlling the heat transfer and, hence, it has very important role on the solidification rate and development of microstructure. In this paper, a linear perturbation method is used to solve a two-dimensional heat conduction problem in which a liquid, becomes solidified by heat transfer to a planar mold of finite thickness. The influence of physical parameters such as the coating material thickness, conductivity and thermal contact resistance on the growth of solidified shell thickness is investigated. The present work can form the thermal part of a subsequent investigation of related thermo elastic stress problems.

Abstract: Periploca sepium Bunge. was tested for salinity tolerance in pot experiments using three levels of salinity, 50, 100, and 200mmol/L.It was observed that the plant growth parameters and net photosynthetic rate (Pn), stomatal conductance (Gs) were enhanced under low salinity levels (50mm/L NaCl.),which reduced strongly with increasing salinity levels. Under 100mmol/L NaCl and 200mmol/L NaCl stress, the decline of Pn was mainly caused by non-stomatal factors.The water use efficiency (WUE), apparent light use efficiency (LUE) , apparent CO2 use efficiency (CUE) were enhanced under low salinity levels (50mm/L NaCl.), the maximum WUE was observed at 100mmol/L NaCl, the minimum WUE was observed at 200mmol/L NaCl, the LUE, CUE were reduced repectively by 52%,47% at 200mmol/L NaCl compared to control.Activities of the antioxidive enzymes superoxide dismutase (SOD), peroxidase (POD),and catalase (CAT) were enhanced by salts treatment (50mm/L NaCl.), but CAT activity decreased under 200 mmol/L NaCl salt stress. Malondialdehyde (MDA) concentration was non-significant versus the control under low salinity levels (50mm/L NaCl.),the largest concentration exposing to 200 mmol/L NaCl. These results suggest a possible use of Periploca sepium Bunge in Yellow River Delta regions,where salinity is often the common major abiotic stress for plants.

Abstract: The effect of activated water on the growth of epidermal cells of newborn mice is studied by cell culture in vitro. To investigate the influence of activated water on the growth of cells, parameters of water are measured. Then, biological mechanism about how the water effects on cells is discussed. It shows that activated water has the promoter action to growth of cells comparing with non-activated water by detecting optical density (OD) at 570 nm with the MTT colorimetry. Statistically, the probability P, less than 0.01, is obvious. We believe that water cluster has become smaller and small water clusters are beneficial for transporting nutrients.

Abstract: The high-pressure crystallized bisphenol-A polycarbonate (BAPC) and BAPC / dioctyl phthalate (DOP) blend samples were prepared in a piston-cylinder apparatus, and the recovered specimens were investigated using scanning electron microscopy (SEM). As for the fracture surfaces without etching technique applied, the detailed information of the crystal morphologies of BAPC was not shown, though the outlines of such aggregations as spherulites and cylindrulite were still exposed due to the high-temperature degradation during the long time crystallization. However, the delicate internal structures of these aggregates were revealed clearly by the introduction of a facile etching method. The used etchant, dimethylacetamide, was capable of dissolving only amorphous, but not crystalline BAPC at room temperature. With the employed selective etching technique, BAPC spherulites with fine structures and different characteristics were observed. Spatial dendrites of the polymer were also disclosed in BAPC samples plasticized with DOP after a deep etching process. Furthermore, by controlling the etching process, unique hierarchical structures, composed of nano-structured micrometer-sized crystalline entities of BAPC, was created on the fracture surfaces. The study presented here suggested that selective etching is a more effective route to reveal the inner structures of polymer crystals, as well as to fabricate new surface active materials, such as a super-hydrophobic surface with self-cleaning effect.

Abstract: The cube texture in rolled and annealed fcc metals and alloys has long fascinated metallurgists because of its high symmetry and extreme sharpness. This paper demonstrates and analyses the texture perfection that is developed in a copper sample. Reasons that have been advanced to explain the development of the texture during recrystallisation and grain growth are discussed. Orientation selectivity is favoured during growth but more particularly in the nucleation stage. Especial attention is paid to the rapid recovery which cube oriented crystals undergo on heating after plane strain deformation and which is the basis for its uniquely preferential nucleation. Various metallurgical factors are known to affect the strength of the cube texture in practice and explanations for some of these are presented.

Abstract: Cast iron components in combustion engines, such as cylinder blocks and heads, are exposed for long periods of time to elevated temperatures and subjected to large numbers of heating and cooling cycles. In complex components, these cycles can lead to localized cracking due to stresses that develop as a result of thermal gradients and thermal mismatch. This phenomenon is known as Thermo-Mechanical Fatigue (TMF). Compacted Graphite Iron (CGI) provides a suitable combination of thermal and mechanical properties to satisfy the performance of engine components. However, TMF conditions cause microstructural changes, accompanied by the formation of oxides at and close to the surface, which together lead to a growth in size of the cast iron. These microstructural changes affect the mechanical properties and accordingly the thermo-mechanical fatigue properties. The aim of this research is to provide insight into the microstructure evolution of CGI, with its complex morphology, under TMF conditions. For this, optical and scanning electron microscopy observations are made after cyclic exposure to air at high temperature, both without and with mechanical loading. It was found that the oxide layers, which develop at elevated temperatures, crack during the cooling cycle of TMF. The cracking results from tensile stresses developing during the cooling cycle. Therefore, paths for easy access of oxygen into the material are formed. Fatigue cracks that develop also show oxidation at their flanks. In order to quantify the oxide layers surrounding the graphite particles, Energy Dispersive X-Ray Analysis (SEM-EDX) and Electron Probe Micro Analysis (EPMA) are used.

Abstract: The effect of water stress on growth and quality of bunching onion（Allium fistulosum L. var. caespitosum Makino）was studied in hydroponics by PEG treatments (10%, 15%, 20%). The results showed that the growth of bunching onion was significantly affected by water stress induced by PEG. Plant height, pseudo-stem weight, total plant weight decreased with PEG concentration increased, the inhibitions in 10% PEG and 20% PEG were greater than in 15% PEG. The root/shoot ratio increased in PEG treatments. Concentrations of allicin and pyruvic acid significantly increased at 10, 17 days after PEG treatments. With PEG concentration increased, concentrations of soluble protein increased.