Key Engineering Materials Vols. 575-576

Abstract: Titanium (Ti) and its alloys have been widely used in orthopedic and dental applications. The bonding between Ti implants and tissues is significantly important in the clinical applications, which is highly relative to the characteristics of implant surface with surface improvement by various coatings such as hydroxyapatite (HA). Meanwhile, the characteristics of modified implants surface can induce special biological response of osteogenic cells to improve the bone-implant bonding. In this paper, in order to improve Ti bioactivity and enhance its osteointegration, calcium phosphate (CaP)/titanate coatings were prepared on Ti with nanoscale surface topographies by a two-step hydrothermal process. Firstly, titanium meshes were treated in sodium hydroxide solutions at two temperatures (200 °C or 240 °C). Then, the treated meshes were immersed in calcium phosphate solutions containing various concentrations of cyclohexane-hexacarboxylic acid (H6L) under hydrothermal conditions. After this two-step process, calcium phosphate deposits, confirmed to be apatite/titanate by energy dispersive X-ray spectroscopy, were successfully formed on the treated Ti mesh surface. These results suggested that this two-step hydrothermal method can be successfully applied to fabricate robust and hierarchical nanostructured coatings of CaP/titanate on Ti implants.

Abstract: Ta-doped TiO₂ films were deposited on surface of nano-grained 316L stainless steel by RF magnetron sputtering technology at room temperature. The surface morphology and friction/ wear properties of TiO₂ films with different Ta-doped content were investigated. The results showed that the proper amount of Ta-doped could refine TiO₂ film particles. The 23% Ta-TiO₂ film on the surface of SNG-316L possessed the lowest friction coefficient (0.147), the best wear-resisting performance and the best friction performance.

Abstract: The 2-thiol benzothiazole was blended in Polyvinylidene fluoride (PVDF) membrane to prepare a kind of PVDF modified ultrafiltration membrane that could be used to remove mercury ion in water treatment. The water flux and retention rate of BSA of obtained PVDF modified ultrafiltration membrane was 222 L/m²·h and 92.33% respectively. The membrane performance were characterized by infrared spectroscopy (FT-IR) and water contact angle measurement. The results showed that, the PVDF modified membrane presented better adsorption ability for mercury ion than the traditional PVDF membrane. After 4 phases of adsorption/desorption, the modified membrane maintained a mercury ion adsorption amount of 0.264 mg/cm² and the desorption rate could reached 94%.

Abstract: The Friedel-Crafts acylation reaction between 5-cyanoindole and 4-chlorobutyryl chloride was conducted in ionic liquid 1-buty-3-methylimidazolium chloroaluminate ([bmiCl/AlCl₃), the major product was 5-cyano-3-(4-chlorobuty) indole. The structure of the product was characterized by Mass and ¹H NMR spectra. When the molar ratio of AlCl₃ to [bmiCl in [bmiCl/AlCl₃ is at 1:1 or less, no 5-cyano-3-(4-chlorobuty) indole could be obtained. The suitable molar ratios of AlCl₃ to [bmiCl in [bmiCl/AlCl₃ were from 2:1 to 3:1, the yields of the major product were from 68% to 70%, respectively. When the molar ratio of [bmiCl/AlCl₃ to 5-cyanoindole was less than 2:1, the acylation reaction was difficult to carry out, because 5-cyanoindole would be not totally dissolve in [bmiCl/AlCl₃ under the situation.

Abstract: Bentonite is applied in the simulative waste water containing Zn (II) ions in this paper, and the influences of initial pH value, temperature, adsorption time, Zn (II) concentration on the adsorption performance have been tested, and thermodynamic and kinetic equation are fitted. The results show that Zn (II) adsorption capacity increases firstly and then tends to balance as the pH increases. The higher the temperature is, the better adsorption capacity is. Zn (II) adsorption occurs within 60 minutes. Langmuir equation is used to fit adsorption thermodynamic equation, which indicates that the adsorption can occur spontaneously, and it is an endothermic and entropy increasing process. In addition, a kinetic equation is more suitable for the description of Zn (II) adsorption mechanism, and adsorption activation energy calculated is 6.90 kJ/mol.

Abstract: Mono-modified β-cyclodextrins ligands, L¹ (6-mono-(N-aminoethyl) amino-β-cyclodextrin) and L² (6-mono-(N-(pyridin-2-yl) ethylamino)-β-cyclodextrin), and their platinum (II) complexes, 1 ([Pt (L¹)Cl₂]·8H₂O) and 2 ([Pt (L²)Cl₂]·4H₂O), were successfully synthesized. As revealed by UV-Vis and CD spectroscopic studies, both complexes mainly adopt a non-intercalative mode with DNA. The interaction between platinum complex 1 and DNA was obviously observed in agarose Gel Electrophoresis. Meanwhile, two ligands L¹, L² and platinum complex 2 have no obvious interaction with DNA. The difference interaction between complexes 1, 2 and DNA should be ascribed to their different structures.

Abstract: Placement for the treatment of coronary atherosclerotic heart disease (CHD) underwent four revolutionary simple balloon dilatation era, bare-metal stent era, drug stent era and completely biodegradable stent era. Completely biodegradable stent is Current research focus. A computer based search of EMbase (1980-01/2011-12), MEDLINE(1966-01/2011-12), CBM(1978-01/2011-08), PubMed (1999-01/2011-12) and CNKI (1999-01/2011-12) was performed. The keywords weredegradable,stents,biocompatibilityin Chinese and English. Indicators including endothelialization degree of coronary artery and incidence of in-stent restenosis were evaluated. 36 articles were included in the final analysis among 262 articles . We systematically evaluated the biocompatibility of vascular stents constructed different biomaterials in these articles and concluded degradable stents may temporarily support vessel wall, smoothly keep blood flow,inhibit thrombosis in an early stage and newborn endomembrane proliferation in later stage and effectively prevent acute vascular occlusion and reduce incidence of restenosis following stent implantation. Biodegradable stents have good biocompatibility and broad application prospects.

Abstract: in order to solve the problem of three-phase static inverter output waveform distortion, detailed analyzed of the voltage distortion caused by the deadband effect and the resulting harmonic components. The control method is proposed to set the deadband time combining with the voltage compensation, while in order to improve the inverter output, the converter output to design a trap filter and a low pass filter cascaded filtering circuit. Simulated analysis the entire system though Saber, using the digital chip TMS320F2812 to achieve appropriate compensation strategies, simulation results and experimental results have all proved the effectiveness of the design method.

Abstract: For the purpose of maximizing the thermal emittance variation of La (Sr, Ca) MnO₃ thin films in the temperature range 173-373 K, thin film optical mechanism and mathematical optimization method were used to determine the thin film structure, including substrate type, thin film chemical composition and the optimized film thickness. The optimization results indicate the variation amplitude of La (Sr, Ca) film infrared emittance reaches to 0.62, which is 35% more than that of ceramic type smart radiation materials. The designed thin film structure can be used to enhance the thermal control efficiency of spacecraft greatly.

Abstract: Among various inorganic antibacterial materials, TiO2 photocatalysis antibacterial materials possess unique properties including long lifespan, nontoxicity, high temperature resistance as well as high physical and chemical stability. More significantly, they are largely involved in many photocatalytic effects such as degradation of organics, purification of air, sewage disposal and self-cleaning.