Advanced Materials Research Vol. 662

Abstract: The isothermal solubility of the ternary system K+,Mg2+/B4O72-—H2O at 25°C has been studied and the phase diagram is determined. The results show that the system is of the simple eutonic type and can be in metastable equilibrium state within 8—16 hours. The phase diagram consists of two solubility branches corresponding to the crystallization areas of K2B4O7•4H2O and MgB4O7•9H2O. The composition of the eutonic point is MgB4O7,0.5279%(Wt%) and K2B4O7,13.9629%(Wt%) respectively. The replicate experiments proved that the phase transformation of hungtsaoite (MgB4O7•9H2O) occurs after a 20 hours epuilibrium.

Abstract: The connected pipe thread will be loosed under the pressure impact and vibration effects. Based on the analysis of the sealing mechanism of pipe thread, the essence of the pipe thread loosening is caused by fretting damage and fatigue. The following three methods are used to reduce the damage: the processing requirements of internal and external screw thread tooth type and size will be improved；the deformations which are made by a screwing torque to the external thread of the material itself will fill the gap in each part after internal and external screw thread are screwed together;plasticity sealing filler are put between internal and external screw thread.

Abstract: The Ag-Pb Deposit in A He Lan was located in the eastern of the East Kunlun with complex structure, strong magma activity and rich mineral resource. The silver lead-zinc bodies were hosted in Yanshanian biotite adamellite (Jηγ) and blackmica granite diorite (Jγδ) and controlled by the fracture zone. The orebodies produced in vein and lenticular with a length of 200m-820m, the average thickness of 0.42m-6.77m. The ore minerals were mainly galena and limonite and the gangue minerals were quartz, feldspar and biotite. The ore textures mainly contained xenomorphic granular, metasomatie-relict, entrapped, interspersed and cataclastic etc. And the major structures were crumb(granular), veinlet and block in the ore area. The ores were the zinc-lead-silver type rich in lead-silver and poor in zinc. The surrounding rocks were biotitemonzogranite (Jηγ) and the stones were the biotitemonzogranite cataclasite and breccia.

Abstract: Being a new whisker products with high performance to price ratio, magnesium borate whiskers with a length of 10 - 50μm and a diameter of 0.5 - 2μm were prepared by molten salt and characterized by XRD, FT - IR, SEM and chemical titration. The experiments show that the synthesis conditions are as follows: raw materials ratio: Mg:B:flux =1:11.05:1-3.5(mol); reaction temperature: 800 - 950°C;reaction time:6 - 10hours; flux: NaCl、KCl or NaOH.

Abstract: The samples with the nominal composition of (1-x)La0.67Ca0.33MnO3/xLaMnO3 with x=0.00, 0.05, 0.15 and 0.25 were fabricated using a special experimental method. The electrical transport behaviour and magnetoresistance (MR) were studied for the composites in magnetic fields H=0.3T, 3T. Experimental results show that with the increasing LaMnO3 doping level, the metal–insulator（M-I） transition temperature TP shifts to lower temperature and the resistivity increases sharply in zero magnetic field. Meanwhile, a significant enhancement in MR is observed for the composites especially in the low temperature range（below TP）. Specially, the maximum MR at 3 T increased from 35% for the pure La0.67Ca0.33MnO3 to 92% for the sample with x=0.25. We suggest that such enhancement in MR is attributed to the strong ferro-antiferromagnetic coupling effects in the composite system, which increase the magnetic disorder at the grain surface and boundary, will improve the spin-polarized tunneling process of the conducting electron between adjacent grains, and thus enhance the MR effects.

Abstract: The chemical composition of biodiesel was analyzed by gas chromatography-mass spectrometry. The cold filter plugging point of biodiesel was measured according to GB/T 20828-2007. The cold flow properties of biodiesel were investigated on the basis of the crystallization theory, including chemical composition and molecular structure. Biodiesel might be considered a pseudobinary mixture, namely, high-melting-point saturated fatty acid methyl esters and low–melting-point unsaturated ones. Bilayer crystal structure of biodiesel was founded. Bilayer structure with headgroups aligned next to each other inside the crystal and away from nonpolar bulk liquid was large platelet lamellae. The results showed that biodiesel was mainly composed of saturated fatty acid methyl esters (C14:0～C24:0 ) and unsaturated ones(C16:1～C22:1、C18:2 and C18:3 ). The cold flow properties for biodiesel were determined mainly by the amount and molecular structure of saturated fatty acid methyl esters. The long-straight-chain saturated fatty acid methyl esters tend to have relatively poor cold flow properties. The cold flow properties worsen with increasing the amount and carbon chain length of straight-chain saturated fatty acid methyl esters. The ways of adjusting biodiesel composition and treating with depression of cold filter plugging point were given; they could improve cold flow properties.

Abstract: Flower-cluster-like hydroxyapatite (HA) microspheres were synthesized through biomimetic method using Ca(NO3)2∙4H2O and (NH4)3PO4∙3H2O as reagents and N-Dodecyl-N, N-dimethyl-3-ammonio-1-propanesulfonate(DDAPS) as template. With increasing the amount of DDAPS, the morphology of HA varies from irregular floccule-like to long-rod-like, then growth into flower cluster microspheres. The possible formation mechanism of morphology change is also discussed.

Abstract: A new approach with adaptive network-based fuzzy inference systems (ANFIS) based on experimental designs was used to model and characterize the tribological behaviors of diamond-like carbon (DLC) films deposited by a magnetron sputtering system. An orthogonal array experiment was introduced and the effects of deposited parameters on the films were systematically explored. The films were analyzed by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). In this study, a group of highly developed hillock-like textures appeared and a lower wear volume loss became visible in the DLC films. Furthermore, the predicted values and experimental results, in which the ANFIS effectively predicts the tribological behaviors of the DLC films, are similar. It was experimentally confirmed the ANFIS predictions agreed with the experiments. Therefore, the experimental results demonstrate the tribological properties on DLC multilayer films are accurately predicted by ANFIS, thereby justifying the reliability and feasibility of the approach.

Abstract: Nickel layers with tensile or pressure residual stress were prepared by electroforming technique from two kinds of electrolyte. Subsequent heat treatment was adopted to get the stress released. The coefficients of thermal expansion (CTEs) were measured with a thermal dilatometer and the relationship between residual stress and the measured CTEs was revealed both from experimental results and theoretical analysis.

Abstract: Biotransformation of persistent organic pollutants (POPs) may be affected by many factors such as biostimulation and bioaugmentation whether beneficial or not. Served as natural healthy medical stone, feed additive and also filters for their adsorption capability in water purification function, was used widely in China. In this paper, PCB 118 was selected as typical polychlorinated biphenyl to study maifanite additive influence on the degradating efficiency of marine fungi for POPs. The results of controlled trials by two penicillium fungus showed thatthe degradation rates of PCB 118 were higher with maifanite as promoting additive than mediums without maifanite. Significant differences were found in further analysis of zeta potential of maifanite in solutions from pH 2 to pH 9 suggesting different adsorption capability of maifanite at different pH levels.