Advanced Materials Research Vols. 160-162

Abstract: In order to investigate the supramolecular assembly and in situ coordination of special amphiphiles with aromatic moieties and without long alkyl chain, a tri-pyridine-based derivative was designed and synthesized. The spreading behaviors of the Langmuir films fabricated from pure water and the subphase containing K2PtCl4 were studied in details. It was found that the compound could form interesting Langmuir films through the interfacial coordination with Pt(II) ions. While well-dispersed nano particles were observed for the films transferred from pure water surface, dense coiled nanofibers could be obtained from Pt(II) subphase, which could be ascribed to the matching direction of coordination and - stacking of aromatic moieties. The transferred LB films were characterized by a series of methods. A rational packing mode was proposed.

Abstract: Cu-Fe-Al composites containing various amounts of graphite additives are prepared by induction sintering method. The mechanical properties of the composites with 0-8 wt. % graphite are measured using the mechanical tester, while the friction and wear properties are evaluated using MRH-3 friction-wear tester. Material components are found by EDS. The worn surface morphologies of the composites are analyzed by means of scanning electron microscopy (SEM). The experimental results show that the composite containing graphite have porous microstructure. The mechanical and tribological properties of composites are related to the induction frequencies and the contents of the graphite as the solid lubricant. The increased graphite content results in reduced mechanical properties and increased friction and wear properties. The composite with 4 wt. % graphite additives and induction frequencies of 35Hz have the lower the friction coefficients and wear rate. Meanwhile, wear mechanism of materials have been changed from abrasive wear to grain wear due to the glaze layer.

Abstract: In order to use existing conditions with requiring no additional cost to improve the seismic capacity of tunnel in soft soil, the impact of grout on seismic performance of tunnel is studied and analyzed in the current paper. The compression modulus of grout could vary to the proportion of materials. The test results show which materials benefit for the compression modulus enhancing. And the results show relative displacement between top and bottom of tunnel, which is an important seismic performance index, decreases with the Es of grout increasing in certain range. Though the Es of grout should be larger than the Es of soil around the tunnel, it is unnecessary to pursue the over high Es of grout. It is necessary to take it into consideration for grout selection so that the tunnel could have better seismic capacity.

Abstract: Most of the synthetic biodegradable polymers are hydrophobic and lack of bioactivity. In contrast, native polymers, such as starch are bioactive and hydrophilic, but starch alone cannot be processed easily. In this paper, the PLGA fibers were modified with starch using coaxial electrospinning to improve its hydrophilicity and biocompatibility. To observe the bioactivity changes of the composite fibers, the fibers were submerged in the SBF for one week. Meanwhile, degradation rate of fibers was tested in PBS. Results showed that the hydrophilicity and degradation rate of fibers were improved after adding starch into the PLGA fibers.

Abstract: Building material industry which belongs to High-carbon is facing severe challenges and great opportunity when coping with global climatic change. Low-carbon is an inevitable trend that economy grows. Low-carbon economy is the backbone for economic transition and also the right way for people move towards future .By means of structural adjustment and technology innovation building material industry is destined to achieve full vitality in the transition to the low-carbon economy.

Abstract: A novel protein delivery system with incorporating PLGA microspheres into porous PNIPAAm hydrogel for sustained delivery of proteins was successfully developed. Distribution of PLGA microspheres in the hydrogel was determined by SEM, and the in vitro protein release characteristics of combination system were investigated by UV-vis spectroscopy. The SEM results showed that PLGA microspheres were encased into the interconnected porous structure of PNIPAAm hydrogel. In vitro release of BSA from combination system exhibited a less burst release followed by a slower sustained release for 20 days. The slow release after the initial burst release was due to the low permeability of BSA in PLGA microspheres. The controlled release of BSA encapsulated within microspheres embedded in scaffolds was better controlled when compared to delivery from PNIPAAm hydrogels alone. The combination systems showed great promise for application in protein delivery.

Abstract: The compressive behaviors of aluminum foam under impact loading are investigated using FEM simulations. The plastic deformation takes place locally and an enhancement of force occurs at the impact end of the samples. By further investigation, this shock enhancement is found decreasing with relative density, but increasing with impact velocity. We also estimate the shock wave velocity. It is found that shock wave velocity increases significantly with impact velocity, but changes slightly with relative density. It is noted that the influence of the sample length on both the shock enhancement and the shock wave velocity is negligible. Finally, the relations of shock enhancement and shock wave velocity with impact velocity are obtained.

Abstract: These new synthesized diazeniumdiolates obtained from D-gluconic acid-bearing chitosan derivatives (SBC) with different molecular weight (280 kDa and 880 KDa) and D-gluconic acid-bearing O-carboxymethyl chitosan derivatives (880 KDa) (SBCS) were used as the NO donor species. Compared with SBC with much higher molecular weight (880 KDa), the SBC with the lower molecular weight (280 kDa) exhibited a high storage capacity for NO (up to 408 nmol NO/mg), greatly increasing the “payload” of released NO with the molecular weight of SBC decreasing. The NO release durations (0.326 h) observed for secondary amine on the SBC with the lower molecular weight (280 kDa) were slightly higher than that of SBC diazeniumliolates with the higher molecular weight (880 kDa), which was only 0.294h. The release duration of SBCS-NO adducts (0.381h) was obviously longer than that of SBC-NO adducts, when they have the same molecular weight (880 kDa).

Abstract: Caprolactam modified casein(CA-CPL) was prepared by using casein and caprolactam firstly. Caprolactam modified casein/waterborne polyurethane composite (CA-CPL/WPU) was prepared from CA-CPL and WPU. Effect of compounding conditions, such as the WPU dosage, compounding temperature and compounding time on CA-CPL/WPU performance were investigated. The results indicated that: CA-CPL/WPU achieved superior comprehensive performance when the WPU dosage was 50%, the compounding temperature and the compounding time was 80°Cand 2 h respectively. Viscosity of CA-CPL/WPU decreased firstly with the increasing amount of WPU When the WPU dosage was lower than 30%, and then increased gradually when the WPU dosage was higher than 30%. The more the dosage of WPU used in the reaction, the less dilution stability CA-CPL/WPU had. Acidic resistance, alkali resistance and electrolyte resistance of CA-CPL/WPU seemed to be invariable after WPU was introduced , but water resistance and softness of the film were improved. FT-IR and DLS results indicated that via the compounding process, certain hydrogen bonding interaction in CA-CPL/WPU took place and the obtained CA-CPL/WPU had a small Z-average size and polydispersity.

Abstract: A more comprehensive,systematic experimentical ground tests of the expansion process of expandable casing were performed. In the tests, 6 5 1/2"N80 casings were selected, of which five had been carried out expansion tests , another one casing was used to test the collapse strength , not been expanded. In the course of the tests,some important parameters of the expandable casing were measured before and after expansion,including the inner and outer diameter, wall thickness, ovality, wall thickness of inequality and the axial deformation, etc..These data provide a reliable basis for the mechanism research of the N80 casing expansion. After expansion tests, these six casing pipes had been performed the collapsing tests in Xi'an Tubular Goods Research Institute of CNPC.The test results show that after expansiong the collaps strength of expandable casing get decreased compared with unexpanded casing which provides a practical basis and reference for the design of expandable casing.