Advanced Materials Research Vols. 562-564

Abstract: La_1-xSr_xMnO₃ (LSMO) (x=0.1, 0.2, 0.3, 0.4)powders were synthesized by high temperature solid phase method, and the crystal structure and morphology were characterized by XRD and SEM. Results indicated that the pure perovskite type LSMO could be obtained after sintered at the temperature of 1000°C for 6h. The average particle size of the powders decreases with the increasing concentration of Strontium.

Abstract: Mg-Zn-Sr alloy sheet; biomaterial; aging treatment; tensile property Abstract. The microstructures and mechanical properties of a novel biodegradable Mg-Zn-Sr alloy sheet aged at 175°C had been studied. The results indicate that the grain size of the casting alloy Mg-Zn-Sr is changed with the change of content of element Sr, and while it is 1.0 (wt.)%, smaller average grain size is gained which is 38μm, as well as it is increased to 1.5 (wt.)%, the grain size is coarsen obviously. The phase precipitated in the alloy sheet is sufficient and distributed in the uniform style at 175°C for 8h which gained the preferable mechanical properties, which the tensile strength reaches 230MPa, hardness 76.1HV as well as prolongation ratio 12.7%.

Abstract: CuO microspheres with a diameter range of 1~3 μm are successfully synthesized with 1 m mol CuCl2 as copper source and 3 m mol Na2CO3 as auxiliary salt at 180 °C for 24 h via the easy hydrothermal method. The phase, the morphologies and optical absorption properties of the samples have been characterized and analyzed by XRD (X-ray diffraction), SEM (Scanning electron microscope) and ultraviolet-visible absorption spectroscopy (UV-VIS), respectively. XRD analysis shows that the phase of as obtained samples is CuO. SEM analysis confirms that the increase of the the auxiliary salt is in favor of the synthesis of CuO microrods. And UV-VIS measurements show that CuO microspheres have a good optical absorption property.

Abstract: Flower-like β-Ni(OH)₂ and nanoflakes have been successfully synthesized with nickel nitrate as nickel source and stronger ammonia water as precipitant via the hydrothermal method. The phase and the morphologies of the samples have been characterized and analyzed by XRD (X-ray diffraction) and SEM (Scanning electron microscope), respectively. XRD shows that the phase of the samples is β-Ni(OH)₂. SEM confirms that The low reaction temperature is propitious to the synthesis of flower-like β-Ni(OH)₂, and with the increase of the reaction time the nanoflakes of flower-like β-Ni(OH)2 become much thinner. However, The high temperature is in favor of the synthesis of β-Ni(OH)₂ nanosflakes, and with the further increase of the reaction temperature.

Abstract: By adding iron oxide to the unitary magnesium oxide, a compound curing agent is made. Studies showed that the tensile strength of phosphate no-baked sand was increased more than 60% by adding the compound curing agent to hardener and the store stability of phosphate no-baked sand was also improved. Changing the percentage of the iron oxide, it showed that the addition quantity of iron oxide and the property of sand wasn't linearity. The highest tensile strength was obtained by 20% content of iron oxide based on total hardener. But a better sand store stability at room temperature and normal humidity air was gained by 30% iron oxide. Putting this no-baked sand under high humidity (more than 90%) condition for 24 hours, the no-baked sand become flexible and the tensile strength is decreased.

Abstract: The paper introduces a new atomization mechanism combining the centrifugal, the oscillating and the impact breakage atomization as a trinity, breaking through the traditional single atomization model. The atomization mechanism here makes full use of the comprehensive effects of the centrifugal atomization, the oscillating atomization and the impact breakage atomization, synthesizing the superiorities of the three as an organic and powerfully efficient whole, and making their mutual reactions stronger step by step. The impact breakage atomization is a new auxiliary mechanism among the three, which can improve the atomizing process of droplets considerably after the centrifugal and the oscillating atomization, producing much better an atomizing result. It is very convenient, simple and direct to fulfill the three-in-one. This atomization mechanism can achieve the goal of even atomization and much tinier droplets and be energy-efficient with low cost as well. Therefore it is a highly practical and useful method.

Abstract: A novel synthetic copolymer (PAA) for bone repair was prepared by melt condensation polymerization with 6-aminohexanoic acid (He) and 4R-hydroxy-L-proline (Hyp). The structure and thermal property were characterized by infrared spectrometer (IR), nuclear magnetic resonance (H1NMR) and differential scanning calorimeter (DSC). The results indicated that the PAA had amide linkages in their polymer chains. The Tg of PAA was 57.56°C and significantly higher than that of nylon6, 50.46°C. Meanwhile, the intrinsic viscosity and mechanical properties were investigated at different He/Hyp ratios. It revealed that appropriate introduction of Hyp group could control the degree of polycondensation and adjusted mechanical properties of PAA obviously close to natural bone. The prepared polymers had about 2.12~18.21 % weight loss after 8-week soaking in PBS, showed degradable properties which was essentials to new bone growth. The copolymer of He and Hyp with ratios of 90/10 had 6.57 % weight loss and maintained the yield compressive strengths with about 67.51 MPa after 8 weeks, which exhibited a compatible mechanical properties and degradation speed for bone repair.

Abstract: Combination of vinyl carbazole and thiophene groups’ excellent thermal properties and optical properties, a novel polymer named poly(2,7-bi-2-thienyl-9-vinyl-9-H-carbazole) was synthesized via radical polymerization and Suzuki reaction. The polymer was characterized using Fourier transform infrared spectrometer(FT-IR), gel permeation chromatography(GPC), differential scanning calorimetry(DSC), and X-Ray fluorescence spectrometer(XRF). It was found that this π-conjugated polymer containing vinyl carbazole and thiophene groups gave a high glass transition temperature (Tg=251°C). This feature made poly(2,7-bi-2-thienyl-9-vinyl-9-H-carbazole) possessing an excellent thermal performance.

Abstract: The profile error of the gear surface of worm produces a great impact to gear characteristic. So, it is necessary to calculate the profile error of the gear surface. In order to develop the manufacturing accuracy of the complex tooth surface of the worm pair, a method to measure the error of the worm was designed in this paper. The profile error of the worm can be calculated based on geometrical operation. To meet the need of quality-controlling and the intelligent machining, the 3-D measuring technology method was adopted to measure the surface of the worm. And through the calculation, analysis and reconstruction, the real outline of the worm pair is redrew. A whole theoretical solid model of worm’s meshing surface with grid can be obtained based on the mathematical modeling. And it is possible to give the data of the recorrection and the feedback by analysing the profile error.

Abstract: The method of mill tool wear condition evaluation based on the extension theory is put forward by the paper. Through researching, the author firstly designs mill tool wear monitoring system which can acquire milling force signal, AE signal, vibration signal and main motor power signal. Based on the matter-element of classics, joint domain and evaluation, and deducting the dependent functions, at last the objective and reasonable evaluation results are got. It is proved that the extension theory is the valid and reliable in evaluating the mill tool wear condition.