Key Engineering Materials Vols. 480-481

Abstract: Objective: In order to prepare for the national competition, change on blood plasma ANP of female boxer in training period was tested. Methods: In six weeks preparing for the training period, test blood plasma ANP on Monday morning in the first, third, fifth, seventh weeks respectively. Results: The analysis revealed: (1) The basis ANP was in lower limit of normal values, with in-depth training, ANP increased gradually, and the levels were significant differences (P<0.01); (2) Subjects grouped according to athletic performance , there was positive correlation between plasma ANP concentration and years of specialized training on elite athletes, correlation coefficient was 0.82, but plasma ANP concentration was not relevant with years of specialized training in general athletes. Conclusions: The longer the training period, the more adaptable remodeling made in heart endocrine capacity, and the higher ANP concentration in resting state.

Abstract: Through the metal inert gas welding (MIG) experiment, the effects of the different welding parameters on the microstructure, the weld configuration and the mechanical properties of the joint of the magnesium (Mg) alloy AZ31B were analyzed. The results indicate that with the increase in the welding current, the microstructure change of the weld is characterized by the grain coarsening, and the microstructure change of the heat affected zone is characterized by the grain coarsening and the broadening of the heat affected zone. An exorbitant welding current is inimical to the weld configuration. With the increase in the welding speed, the welding linear energy decreases, inducing the formation of the finer equiaxed grains in the weld. Moreover, the grains in the heat affected zone are also with the trend of the refinement, and thus the mechanical properties of the joint increase. The optimal welding current and speed in our experiment are 160-170A and 400-450mm/min, respectively.

Abstract: Low-calcium fly ash is paid much attention for its wide use in engineering, the research and application technology of it are very mature, but as to high-calcium fly ash concrete, the researches on stability, mechanical property and durability of it are very less , The existing researches are still inadequate for practice of engineering. As to this problem, using small shek kip hydropower project as example, the volume stability of high-calcium fly ash concretes with different fly ash dosages are tested, then the optimal dosage of the high-calcium fly ash is determined; based on this, the impacts of high-calcium fly ash on the performance of mechanical properties , impermeability and frost resistance of concrete are studied; Finally, macro performance is analyzed from a micro-mechanism point of view through taking the electron micrograph. As the study shows, the optimal dosage of high-calcium fly ash should be taken as 20% -25%; for the concrete with special requirements, the dosage can be relaxed to 30% when the high-calcium fly ash achieves high quality. The compressive strength of high-calcium fly ash concrete is higher than the low-calcium fly ash concrete. Strength development advantage of high-calcium fly ash concrete reflects at the early age, this advantage takes the trend of weakening as the development of age. Concrete mixed with high-calcium fly ash has good performance in impermeability. The high-calcium fly ash has high activity, the high-calcium fly ash and secondary hydration reaction products can be filled into the pore capillary and cracks of the concrete structure, improving the pore structure, thereby increasing the density of cement paste. High-calcium fly ash concrete has good performance in frost resistance. The destructive effects of freeze-thaw cycles on cement structure has connection with the microstructure of cement and impermeability , the improvement of impermeability avoids the water entering into the concrete, reduces the risk of destruction caused by frost heave.The study on micro-mechanism proves well the macro-phenomena above.

Abstract: Effect of Lithium Chloride (LiCl) and Sodium Propionate (CH3CH2COONa) on growth of Lactobacillus acidophilus, Bifidobacterium bifidum, Lactobacillus bulgaricus, Lactobacillus casei and Lactobacillus rhamnosus was studied by measuring optical density at 600nm (OD600) and pH using MRS media as the control. The addition of each substance (%, w/v) was 0.025%, 0.05%, 0.1%, 0.2% and 0.3%. Results were as follows: addition of LiCl has the significant inhibition on growth of Lactobacillus acidophilus, Bifidobacterium bifidum and Lactobacillus bulgaricus at incubation 12h. The optimum selective concentration of LiCl in MRS media was 0.1% both for Lactobacillus acidophilus and Lactobacillus bulgaricus. Lactobacillus rhamnosus can tolerate the substances mentioned above. Sodium Propionate has no effect for any of five strains.

Abstract: Effect of steroidal saponins fromFructus tribuli on growth of Bifidobacterium bifidum BB01, BB03 and Lactobacillus acidophilus LA09 was studied by measuring optical density at 600nm (OD600) and pH using MRS media as the control. The concentration of steroidal saponins (w/v) added in was 0.05%, 0.10%, 0.15%, 0.20% and 0.25%. Results were as follows: addition of steroidal saponins could improve the buffer ability of MRS and promote the growth of Bifidobacterium bifidum BB01 and BB03. The optimum concentration of nutrient supplement in MRS media was 0.20% at incubation 24h for Bifidobacterium bifidum BB01 and 0.25% at incubation 24h for Bifidobacterium bifidum BB03. Addition of steroidal saponins on Lactobacillus acidophilus LA09 didn’t play an obvious role in promoting growth when it was in high level.

Abstract: Magnetic Shape Memory Alloys（MSMA）have attracted considerable attention due to their potential application in actuators driven by temperature and magnetic field . Research on shape memory alloys found that the Heusler alloys of MSMA body-centered cubic lattice structure were occured giant strains by magnetic fields[1-4]. Japanese scholars found the new magnetic Shape Memory Alloys Ni-Mn-In and Ni-Co-Mn-In Heusler alloys completely under the control of the magnetic shape fields in 2005[5-7]. In applied MSMA fields, the Ni-Mn-In Heusler alloys start the possibility of using shape memory effect only driven by magnetic field. However, the high brittleness of polycrystalline intermetallic compounds hinders the practical use. Until now, the investigated alloys are ongoing research to resolve, the investigation was carried out to employ rapid quenching by melt spinning to produce Mn–Ni–In Heusler alloys by JLSánchez Llamazares et al [8], and the ribbons of Ni-Mn-In Heusler alloys grain preferential texture. We use the rare earth Gd to improve machining performance of the new alloys, and study the change of microstructure and magnetic properties of alloys which may be a subject of significant scientific and technological interests.

Abstract: Through measuring the respiratory function of 17 outstanding U-Half Pipe snowboard athletes, compared with the normal students，to understand the basic conditions of their respiratory system. The results showed that: there were higher levels in the expiratory volume (EV) and expiratory reserve volume (RV) of female snowboard skiers than that of normal students; there were higher levels in small airway ventilation and pulmonary ventilation (PV) of outstanding U-Half Pipe snowboard athletes than that of normal students; the FEV1/FVC of outstanding U-Half Pipe snowboard athletes were below 80%.

Abstract: In SMT production line, different types of components may have the same shape but providing different functions. The only difference between these components is the text on surface of a component indicating its type. Therefore, not only geometry defect inspection but also text detection is needed in component inspection to avoid wrong use of components. Traditional algorithms based on pixel comparison of text image are time consuming and sensitive to tiny change of the text as well. A concise text detection algorithm based on color projection is proposed. The algorithm transfers two-dimensional color image to one-dimensional curve for comparison by projection of the text image, which greatly reduces the computing amount, increases speed and makes the algorithm less sensitive to displacement or rotation of the text. Experiments show that the algorithm can ensure effective real-time text detection.

Abstract: Chemical control of post-emergency weeds in dichondra turfgrass is always a difficult problem. Herbicides application in dichondra turf to control postemergency weeds must be highly selectively because of heavy similarity between dichondra turfgrass and broadleaf weeds. Chemical control experiment was conducted to screening effectively herbicides. The results indicated that SHIBAGEN 300~450/ hm2 can control post-emergency broadleaf weeds and purple nutsedge, shortleaf nutsedge, goosegrass，crabgrass and barnyardgrass effectively. And SHIBAGEN possessed both pre-emergency elimination and postemergency stem-leaf killing results, and its residual effect can lasted up to 90 days. Methsulfuron-methyl 45g/ hm2 control broadleaf weeds significantly, and can mix with shibagen herbicides to magnify control spectrum.

Abstract: A biochip for building up self assembled ferromagnetic structures was designed. The magnetic structures are self assembling onto magnetic seeding points which are arranged in a periodic hexagonal structure on the bottom of the chip. The individual shapes of the ferromagnetic structures can be controlled by an applied external magnetic field. This periodic arrangement of adaptable ferromagnetic structures is well suited for selective and dynamic cell trapping. A biochip designed for lab experiments and a simulation model for optimizing the magnetic structures is presented.