Advanced Materials Research Vols. 152-153

Abstract: Konjac Glucomannan(KGM) was denatured by Carboxylmethylation to prepare Carboxymethyl konjac glucomannan(CMKGM) as coating material of 5-aminosalicylic acid(5-ASA) tablets. The 5-ASA release properties of the tablets were measured in vitro in the gastrointestinal tract simulation environment and in buffer solutions with β-mannase of pH 6.8 at 37 ± 0.5 degrees. The properties of the CMKGM were analyzed by FTIR spectra, viscosity measurement and swelling measurement. The integrality of the 5-ASA was investigated by ultraviolet spectrometry. The viscosity and swelling showed that CMKGM has lower swelling and lower viscosity compared to KGM. 5-ASA was released least in stimulating gastric environment and in pH 6.8 phosphate buffers,while the preparation was fast released in pH 6.8 phosphate buffers with β-mannase. The preparation was released 14% after 4 hours in pH 6.8 phosphate buffers , at the same time the preparation in pH 6.8 phosphate buffers with 0.2u ml-1 β-mannase was released 97% in 12 hours.The results suggested that CMKGM may be a useful carrier of 5 –ASA for colon-specific delivery. It has a potential use for advanced controlled release.

Abstract: The temperature and strain distributions of the mockup composed of Be, Cu-alloy with distinct structural material (SS316L and China Low Activation martensitic steel (CLAM)) were calculated and analyzed during thermal cycling, based on a high heat flux (HHF) test recently reported with heat flux of 1.5MW/m2. The calculated temperature and strain results, in which SS316L is as the structural material, showed a good agreement with HHF test. By substituting CLAM steel for SS316L the contrast analysis indicates that the thermo-mechanical property for CLAM steel is better than that of SS316 at the same condition. Furthermore, the temperature and strain distributions of the FW were calculated under the condition of normal ITER operation: the surface heat flux is about 0.5MW/m2 and volumetric heating due to neutron radiation is on the order of 15~20 MW/m2.

Abstract: Two-step method is used to research stress and its distribution in 64×64 InSb infrared focal plane array (IRFPA) employing finite element method. First, a small 8×8 InSb IRFPA is studied by changing indium bump diameters from 24μm to 36μm, with indium bump thickness 20μm and InSb thickness 10μm, the simulated results show that von Mises stress in InSb chip is dependent on indium bump diameters, the varying tendency is just like the letter V, here when indium bump diameters is set to 30μm, the smallest von Mises stress is achieved and its distribution in InSb chip is uniform at contacting areas. Then, InSb IRFPA array scale is doubled once again from 8×8 to 64×64 to learn the effect from array size, thus, the stress and its distribution of 64×64 InSb IRFPA is obtained in a short time. Simulation results show that von Mises stress maximum in InSb chip and Si readout integrated circuit almost do not increases with array scale, and the largest von Mises stress is located in InSb chips. Besides, stress distribution on the bottom surface of InSb chip is radiating, and decreases from core to four corners, and stress value at contacting area is smaller than those on its surrounding areas, contrary to stress distribution on top surface of InSb chip.

Abstract: Tea polyphenol loaded alginate-chitosan microspheres were prepared by ionic gelation method for controlling tea polyphenol release by using various combinations of chitosn and Ca2+ as cation and alginate as anion.Scanning electron microscopy were used to investigate the surface characteristics of tea polyphenol loaded microspheres. These microencapsulated beads were evaluated as a pH-sensitive system for delivery of tea polyphenol. The main advantage of this system is that all procedures used were performed in aqueous medium which may preserve the tea polyphenol bioactivity. At pH7.4, the amounts of tea polyphenol released increased significantly as compared to those released at pH1.2. It is evident that the rate of tea polyphenol release could be controlled by changing the chitosan and the calcium chloride concentrations.

Abstract: Two fractions, such as Fr1-3 and Fr2-2, were obtain after separating and purifing crude kiwifruit glycoprotein by using Sepharose Cl-6B gel column and DEAE Sepharose Cl-6B ion exchange column. In the UV and Infrared Spectroscopy of Fr1-3 and Fr2-2, the characteristic absorption peaks of sugar and protein were both found.The molecular weight of Fr1-3 is 30497，the molecular weight of Fr2-2 is 28567. Both of Fr1-3 and Fr2-2 have 17 amino acids, However, the amino acid content of them is different.

Abstract: As a new biomaterial, recombinant spider silk protein has attracted much attention in tissue engineering. The pNSR-16/ BL21(DE3)pLysS strains fermented and produced the recombinant spider silk protein, which was then cast into scaffolds. NIH-3T3 cells were cultivated with extractions of the scaffolds in vitro. The cytotoxicity of scaffolds was analyzed with a MTT assay. The performances of cells adhesion, growth and expression on the scaffolds were observed with SEM, HE staining and immunohistochemistry. Compared with the control, the extract fluid of materials culturing the NIH-3T3 cells was not apparently different. NIH-3T3 cells could adhere and grow on the scaffolds and secret FGF-2. The pNSR-16 recombinant spider silk protein scaffolds has satisfactory cytocompatibility and the scaffolds are ideal scaffold material for tissue engineering.

Abstract: The semi-solid A356 alloy slurry is prepared by slightly electromagnetic stirring with Ti-based refiner. The effects of the refiner on the morphology and the grain size of the primary phase in the slurry are researched. The results indicate that the slurry with particle-like and rosette-like primary phases can be prepared by slightly electromagnetic stirring with the refiner. Compared with the A356 alloys without the refiner, the grain size and particle morphology of primary phase as well as the distribution of the grain with particle-like or rosette-like along radial in the ingot in A356 are markedly improved by the refiner.

Abstract: To improve the wear resistance of ductile cast iron, plasma beam remelt-solidified hardening on the surface is adopted. Scanning electron microscope and micro-hardness tester is used to analyze the microstructure and performance for plasma beam remelt-solidified layer of nodular cast iron. The results show that micromelted-solidified hardening of the nodular cast iron surface can be obtained when the operating current is up to 50A. Along with the operating current increases, the width and depth of remelt-solidified layer and hardened layer increase, but the hardness goes down. After the hardening, graphite phase in remelt-solidified region is vanishing. The microstructure of remelt-solidified region is tiny ledeburite and remained austenite and of transformation hardening region is acicular martensite, remained austenite，spheroid graphite and ferrite .In transition region, martensite shell around nodular graphite appears, which is advantageous to enhance the wear resistance. From the surface to inner, the microhardness declines first and then increases, after achieving the maximum value the hardness slowly drops. The highest microhardness appears at the second-surface layer which has a certain distance to the surface.

Abstract: TiNbSn alloy has high specific strength, low modulus of elasticity, excellent corrosion resistance, no side effects, such as toxic and exhibits shape memory effects after appropriate technical processing. This alloy may substitute as NiTi shape memory alloy to become the new generation of biological materials. It has been reported the studies of this alloy, such as the component and proportion, processing technology, mechanical properties and corrosion resistance. Based on the previous research, the bio-metal material, Ti-10Nb-5Sn alloy was heated and cooled repeatedly in a heater system located in TEM chamber and, at the same time, was observed in situ using a high resolution transmission electron microscope to study the memory property of the alloy and the mechanism of the transformation between austenite β and martensite phase. The results show that, during heating stage from 295K to 400K, the martensite began to dissolve at 355K, and the martensite disappeared completely at 385K, meanwhile, the austenite was created. During cooling stage from 400K to 295K, the martensite begins to take shape at 353K and the transformation was completed at 333K. The alloy can memory the room and high temperature structures, showing two-way memory functions. The high-temperature austenite of Ti-10Nb-5Sn alloy shows body-centered cubic β phase with the unit cell parameter a=0.3283nm; the martensite at room temperature shows orthorhombic NbTi4 phase (M) with the unit cell parameters a=0.3152nm, b=0.4854nm, c=0.4642nm. The orientation relationship between M phase and β phase is , , , , and . The crystal plane , as the habit plane, transforms into during the transformation from β to M phases. The martensite transformation mechanism is that the and transform to and through the tiny migration of atoms.

Abstract: The particle-reinforced composite solder is prepared by adding 1 μm Ag, 1 μm Ni and 8 μm Cu into Sn0.7Cu eutectic solder which serve as the base material in current research. The formation of a thin layer of intermetallics around the particle-reinforced will promote the closer integration between base-solder and particle-reinforced, and thus form the particle-reinforced composite solder. The appropriate reinforcement particles were selected and the effects of reinforcement particles on physical properties, mechanical properties and solderability of the composite solder were studied. The spreading property of Ni (3 vol %) particle-reinforced Sn0.7Cu based composite solder was the worst among Sn0.7Cu based composite solders. The spreading property of the Cu particle-reinforced Sn0.7Cu based composite solder was worse than those of Ag particle-reinforced Sn0.7Cu based composite solders. So the conclusion is drawn that Ag particles are considered as the most appropriate reinforced particles for Sn0.7Cu based composite solders.